JPH11288111A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of the light fatigue of the photo-receptor due to repeated use and rise of residual potential resulting from it by incorporating a specified amount of trans type or more in a specified butadiene compound. SOLUTION: A photosensitive layer formed on the conductive substrate of the electrophotographic photoreceptor contains at least a charge generating agent and the charge transfer agent of the butadiene compound comprising the trans type of formula I and the cis type of formula II in an amount of trans type of >=60 mol.% of the butadiene compound. This electrophotographic photoreceptor is formed, for example, in the case of the functionally separated type by laminatating a charge generating layer containing a charge generating agent on a conductive substrate and then, a charge transfer layer containing the charge transfer agent, thus forming the photosensitive layer comprising the charge generating layer and the charge transfer layer, thus permitting light fatigue due to repeated use and the resulting rise of residual potential to be prevented.

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 having a photosensitive layer containing a specific butadiene compound as an essential component.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as selenium, selenium / tellurium, diarsenic triselenide, cadmium sulfide, zinc oxide and amorphous silicon have been generally used as photoconductive materials for electrophotographic photoreceptors. However, these photoconductors have drawbacks such as practically poor flexibility, sensitivity to heat and mechanical shock, and high manufacturing cost. In recent years, a photoreceptor using an organic material which has eliminated these disadvantages has been proposed and put to practical use. This organic photoreceptor generally has a so-called function separation type in which a charge generation layer and a charge transfer layer are laminated on a conductive support, and a photosensitive layer serving also as the two layers is laminated on a conductive support. The function and use type is widely known.

As a function-separated type, for example, a photosensitive layer in which a charge generation layer containing a cyanine pigment or the like as an active ingredient and a charge transfer layer containing an organic compound such as a hydrazone-based, pyrazoline-based, or oxadiazole-based compound is laminated. The body is known, and many compounds are known to be effective for both the charge generating agent and the charge transfer agent.

In such a function-separated type photoreceptor, the charge generation agent absorbs light in the charge generation layer to generate carriers, and the generated carriers are injected into the charge transfer layer and move through the charge transfer layer. However, it is important to select a material that allows the charge generating agent to move to the surface without being trapped by impurities or the like in the moving layer. The electrophotographic characteristics of the function-separated type electrophotographic photoreceptor are greatly affected by the combination of the charge generating agent and the charge transfer agent.

[0005]

However, when many compounds are used as a photosensitive layer by combining a charge generation layer and a charge transfer layer, those which satisfy the characteristics and conditions of a photoreceptor that are practically required are: Very little is known from the results of experiments. In particular, few of them satisfy the repetition characteristics of charging and exposure by a known electrophotographic process, and when repeated charging and exposure are performed, the residual potential, which is considered to be caused by accumulation of charge traps in the charge transfer layer, is increased. Fogging easily occurs. Under the influence, in particular, in a reversal developing method used in a printer or the like, a density change due to repetition occurs. These are presumed to be due to light fatigue. The above problem also occurs in a single-layer function-type photoconductor in which a phthalocyanine pigment, a bisazo pigment, or the like is dispersedly applied to a binder resin.

[0006]

Means for Solving the Problems The present inventors have made intensive studies and conducted experiments on an electrophotographic photosensitive member capable of preventing light fatigue of the photosensitive member during repeated use and an increase in residual potential due to the light fatigue. As a result, the above-mentioned problem can be solved by containing the trans form in a specific butadiene compound in a certain amount or more, and it has been found that the characteristics as an electrophotographic photoreceptor are extremely excellent. It has been provided.

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer having at least a charge generating agent, a charge transfer agent, and a binder resin formed on a conductive support. A butadiene compound represented by the trans-form [I] and the cis-form of the formula [II];
Wherein the trans form is 60% by weight or more of the butadiene compound.

Embedded image

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the electrophotographic photosensitive member according to the present invention will be described below in detail. The butadiene compound in which the trans form of the formula [I] according to the present invention is 60% by weight or more of the butadiene compound can be obtained as follows.

That is, a mixture of a cis-isomer and a trans-isomer is obtained by the method described in Japanese Patent Publication No. 21646/1995. This product is obtained by column chromatography, recrystallization or a combination of these treatments to obtain the compound of the formula [I]
1- (p-Diethylaminophenyl) -1,4,4-triphenylbutadiene in which the ratio of the trans-form represented by the formula to the mixture of the cis-form and the trans-form is 60% by weight or more can be synthesized.

The present invention provides, for example, a function in which a charge generation layer containing at least a charge generation agent is formed on a conductive support, and a charge transfer layer containing at least a charge transfer agent is formed thereon. It is applied to a separation type electrophotographic photosensitive member. In this case, a photosensitive layer is formed by the charge generation layer and the charge transfer layer.

The present invention also provides a single-layer electrophotographic photosensitive member in which a charge generating agent and a charge transfer agent are contained in the same layer, and a reverse-stacked electrophotographic photoconductor in which a charge transfer layer and a charge generation layer are stacked in this order. The invention can be applied to a photoreceptor and the like.

Examples of the conductive support usable in the present invention include simple metals such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum and indium, and alloys thereof. Processed products and conductive materials such as the above metals and carbon, which are treated by vapor deposition, plating, etc., to give conductive plastic plates and films, and conductive materials coated with tin oxide, indium oxide, and aluminum iodide. The conductive support can be formed by using various conductive materials, such as conductive glass, without being limited by the type or shape. The conductive support may be in the form of a drum, a rod, a plate, a sheet, or a belt.

Examples of the charge generating agent that can be used in the present invention include inorganic charge generating materials such as selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salt dyes, thiapyrylium salt dyes, and azulhenium salt dyes. Cation dyes such as thiocyanine dyes and quinocyanine dyes; polycyclic quinone pigments such as squarium salt pigments, phthalocyanine pigments, anthantrone pigments, dibenzopyrene quinone pigments, pyranthrone pigments, perylene pigments, and indigo pigments Materials selected from organic charge generating substances such as pigments, quinacridone pigments, azo pigments, and pyrrolopyrrole pigments can be used alone or in combination, and can be used as a vapor deposition layer or a coating layer.

Among the above organic charge generating substances,
Particularly preferably, Chem. Rev .. 1993, 93,
p. 449-486.
I can do it. Of these, phthalocyanine pigments are particularly
Preferred. Here, especially as phthalocyanine pigments
Represents an alkoxy titanium phthalocyanine (Ti (O
R) 2Pc), oxytitanium phthalocyanine (Ti
OPc), copper phthalocyanine (CuPc), metal-free lid
Russian Nin (H_TwoPc), hydroxygallium phthalos
Anine (HOGaPc), vanadyl phthalocyanine (V
OPc), chloroindium phthalocyanine (ClIn
Pc). More specifically,
Α-TiOPc, β-TiOPc, γ-T
iOPc, m-TiOPc, Y-TiOPc, A-type
-TiOPc, B type-TiOPc, TiOPc amorph
As an example. Metal-free phthalocyanine (H_TwoPc)
As α-H_TwoPc, β-type-H_TwoPc, τ₁Type-
H_TwoPc, τ _TwoType-H_TwoPc, x-type -H_TwoPc
It is. These phthalocyanines are mixed and milled.
To form a mixture or form a new mixed crystal system
Can be used. For example, Japanese Patent Application Laid-Open No. 4-371962,
JP-A-5-2278, JP-A-5-2279, etc.
Oxytitanium phthalocyanine and vanadylf
Mixed crystals of tarocyanine, JP-A-6-148917,
Kaihei 6-145550, JP-A-6-271786,
Oxygens described in JP-A-5-297617 and the like
Titanium phthalocyanine and chloroindium phthalos
Mixed crystals of anine can be used. Diffraction spectrum
The following Bragg angle (2θ ± 0.2 °)
Oxytitanium phthalocyanine is preferably used
can do.

In the CuKα X-ray diffraction spectrum, Bragg angles (2θ ± 0.2 °) 7.4 °, 9.3 °, 1
0.6 °, 13.2 °, 15.1 °, 15.7 °, 1
6.1 °, 20.8 °, 23.3 °, 26.3 °, 2
Oxytitanium phthalocyanine having a diffraction peak at 7.1 ° In the CuKα X-ray diffraction spectrum, the Bragg angle (2
θ ± 0.2 °) 9.3 °, 10.6 °, 13.2 °, 1
5.1 °, 16.1 °, 20.8 °, 23.3 °, 2
Oxytitanium phthalocyanine having diffraction peaks at 6.3 ° and 27.1 ° In the CuKα X-ray diffraction spectrum, the Bragg angle (2
θ ± 0.2 °) In the oxytitanium phthalocyanine CuKα X-ray diffraction spectrum having diffraction peaks at 13.6 °, 24.1 °, and 27.3 °, and having a maximum peak at 27.3 °, the Bragg angle (2
θ ± 0.2 °) 7.5 °, 9.0 °, 10.2 °, 2
In the oxytitanium phthalocyanine CuKα X-ray diffraction spectrum having diffraction peaks at 4.1 °, 27.1 °, and 28.5 °, and 27.1 ° being the maximum peak, the Bragg angle (2
θ ± 0.2 °) 7.4 °, 13.0 °, 20.5 °, 2
Oxytitanium phthalocyanine having diffraction peaks at 6.2 ° and 27.0 °

The azo pigments include monoazo pigments, bisazo pigments, trisazo pigments, and tetrakis pigments. Examples of the bisazo pigment include those represented by the following formula (A).

Embedded image Cp ¹ —N = N—Ar—N = N—Cp ² (A) where Ar is represented by the following formula:

Embedded image Cp ¹ and Cp ² are represented by the following equations.

Embedded image (In the formula, R ⁴² , R ⁴³ , R ⁴⁴ and R ⁴⁵ may be the same or different and represent a hydrogen atom, a halogen, a lower alkyl group, a lower alkoxy group, a nitro group or a cyano group.)

The trisazo pigment is represented by the following formula (B).

Embedded image In the formula (B), Ar represents a trifunctional group represented by the following formula.

Embedded image Cp ¹ and Cp ² are the same as defined in formula (A), and Cp ³ is synonymous with Cp ¹ and Cp ² .

Further, a perylene compound or a polycyclic quinone compound represented by the following structural formula is also preferable.

Embedded image Other than these, any material can be used as long as it absorbs light and generates charges with high efficiency.

The charge transfer layer of the electrophotographic photoreceptor of the present invention comprises:
A compound comprising a butadiene compound represented by the trans-form of the formula [I] and the cis-form of the formula [II], wherein the trans-form of the formula [I] is at least 60% by weight of the butadiene compound and a binder. It is formed by applying a solution dissolved in an appropriate solvent to a conductive support or a charge generation layer and drying the solution. On the other hand, it contains a charge generating agent and a butadiene compound represented by a trans form of the formula [I] and a cis form of the formula [II], and the trans form of the formula [I] is 60% of the butadiene compound.
The monolayer type photoreceptor containing the compound of not less than 1% by weight contains a charge generating agent and a butadiene compound represented by a trans-form of the formula [I] and a cis-form of the formula [II];
Is obtained by dissolving or dispersing a compound in which the butadiene compound is 60% by weight or more of the butadiene compound in a suitable solvent together with a binder, on a conductive support, and drying. Further, an electron acceptor type compound (for example, a fluorenone derivative, a quinone derivative, phthalic acid, melitic acid, etc.) and a trans form of the formula [I] and a formula [I
A single-layer type photoreceptor containing a butadiene compound represented by the cis-form of the formula [I] and a compound wherein the trans-form of the formula [I] is at least 60% by weight of the butadiene compound can be obtained in the same manner. it can. Binders generally affect the durability of a photoreceptor by affecting not only electrical properties such as chargeability and sensitivity of the photoreceptor, but also mechanical strength such as adhesive strength, hardness and abrasion resistance of the photoreceptor layer. . In addition, since the production conditions such as the viscosity in the coating liquid and the dispersion stability of the charge generating material are affected, the performance of the photoreceptor may be significantly changed by selecting the binder.

Accordingly, examples of the binder resin used in the present invention include polycarbonate resin, styrene resin, acrylic resin, styrene-acryl resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin, and chlorinated polyether resin. , Vinyl chloride-vinyl acetate resin, polyester resin, furan resin, nitrile resin,
Alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diallylate resin, polysulfone resin, polyethersulfone resin, polyallyl sulfone resin, silicone resin, ketone resin, polyvinyl butyral resin, Polyether resin, phenol resin, EVA (ethylene / vinyl acetate / copolymer) resin,
ABS (acrylonitrile-butadiene-styrene) resin, photo-curable resin such as epoxy arylate and the like can be mentioned. In addition to such insulating polymers, organic photoconductive polymers such as polyvinyl carbazole, polyvinyl anthracene, and polysilane can also be used.

It is particularly preferable to use polycarbonate among these binders. As a polycarbonate that can be suitably used, a bisphenolmethane-type polycarbonate represented by the following general formula (G) can be given. Specifically, bisphenol A type polycarbonate represented by the formula (G-1) (such as Iupilone E series manufactured by Mitsubishi Gas Chemical) and bisphenol Z type polycarbonate resin represented by the formula (G-2) (for example, Mitsubishi Gas And polycarbonates represented by the formulas (G-3) and (G-4), and mixtures or copolymers thereof. It is desirable that these polycarbonates have a high molecular weight so that cracks and scratches do not easily occur when the photosensitive member is formed.

[0022]

Embedded image (In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. R ¹¹ and R ¹² may be cyclically bonded, and R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ ,
R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a phenyl group which may have a substituent, n represents an integer)

[0023]

Embedded image

Examples of the copolymer include those represented by the general formula (G)
Any suitable combination of the monomer units can be used, and preferably, a monomer unit represented by formula (H) is disclosed in JP-A-4-179.
No. 961 discloses a bisphenol / biphenol-type copolymerized polycarbonate resin.

Embedded image (In the formula, R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. R ¹¹ and R ¹² may be cyclically bonded, and R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ ,
R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group which may have a substituent. . R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms. A phenyl group which may have a substituent or a substituent;
²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ may be each independently cyclically bonded. n and m represent an integer. )

Specific examples of the bisphenol / biphenol type polycarbonate resin include, for example, bisphenol A / biphenol type polycarbonate resin represented by the following structural formula (H-1, H-2, H-3 or H-4). (N and m represent integers, and the ratio of n and m may be any ratio, but n / n + m is preferably 0.1 to 0.9, more preferably 0.7 to 0.9) Can be mentioned.

Embedded image

In addition to the above-mentioned polycarbonates, polycarbonates having a repeating unit represented by the following structural formula (i) disclosed in JP-A-6-214412 can be used.

Embedded image Further, a polycarbonate represented by the following general formula (J) disclosed in JP-A-6-222581 can also be used.

Embedded image (Wherein R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, 3 to 8
An alicyclic group having a membered carbon atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group which may be substituted with an alkoxy group having 1 to 4 carbon atoms or a halogen atom, or 1 carbon atom
A benzyl group which may be substituted by an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. n
Represents an integer. )

The binder comprises a butadiene compound represented by a trans-form of the formula [I] and a cis-form of the formula [II], and the trans-form of the formula [I] is 60% by weight of the butadiene compound. % Of the compound and the charge transfer material may be mixed at any ratio, but usually the charge transfer material is 10 to 1000 parts by weight, preferably 30 to 500 parts by weight, per 100 parts by weight of the binder. More preferably 40 to
200 parts by weight. The thickness of the obtained charge transfer layer is generally 2 to 40 μm, but a preferable range is 5 to 40 μm.
m, more preferably 10 to 30 μm. The organic solvent used is not particularly limited, but includes alcohols such as methanol, ethanol and isopropanol, pentane, hexane, heptane, octane, cyclohexane and saturated aliphatic hydrocarbons such as methylcyclohexane,
Ketones such as acetone, methyl ethyl ketone and cyclohexanone, N, N-dimethylformamide, N, N-
Amides such as dimethylacetamide, sulfoxides such as dimethylsulfoxide, tetrahydrofuran, dioxane, ethers such as ethylene glycol dimethyl ether, ethyl acetate, methyl acetate, propyl acetate,
Esters such as butyl acetate, methylene chloride, chloroform, 1,2-dichloroethane, dichloroethylene, trichloroethylene, trichloroethane, aliphatic halogenated hydrocarbons such as carbon tetrachloride, and aromatics such as benzene, toluene, xylene, chlorobenzene, and dichlorobenzene. Compounds and the like can be used alone or in a mixture thereof. When the charge transfer layer is formed by coating, it can be performed by a coating method such as a dip coating method, a spray coating method, a spinner coating method, a wire bar coating method, a blade coating method, a roller coating method, and a curtain coating method. . Drying after application is preferably a method of drying at room temperature and then heating and drying. In general, the heating and drying is preferably performed at a temperature of 30 to 200 ° C. for 5 minutes to 2 hours in a still or blowing condition.

Further, the charge transfer layer in the present invention may contain other charge transfer materials and various additives as necessary. Other charge transfer materials include
For example, a diamine compound represented by the following general formula (K) can be given.

Embedded image (Wherein R ⁵¹ and R ⁵² may be the same or different and represent a hydrogen atom, a halogen atom, a methyl group, a methoxy group or a phenyl group, and Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are the same or different. Represents an α-naphthyl group, β-naphthyl group, phenyl group or p-biphenyl group which may be substituted.) Among them, the following general formulas (K-1) and (K)
-2) and a diamine represented by the formula (K-3) are preferable.

Embedded image

Further, hydrazone compounds represented by the following general formula (L) described in JP-B-55-42380, JP-A-60-340999, JP-A-61-23154, etc., US Pat. No. 3,873,312, etc. , A distyryl compound represented by the following general formula (M), other triphenylmethane derivatives, N, N-diphenyl-N-biphenylamine derivatives, N, N-diphenyl-
Triarylamine derivatives such as N-terphenylamine derivatives, tetraphenylbutadiene-based compounds other than the butadiene compound which are essential components of the present invention, α-phenylstilbene derivatives, bisbutaline described in JP-A-7-173112 Examples include, but are not limited to, dienyltriphenylamine derivatives.

Embedded image (Wherein, R ⁶¹ and R ⁶² may be the same or different and each may have a lower alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent. And R ⁶³ and R ⁶⁴ may be the same or different,
Optionally substituted lower alkyl group, an aryl group which may have a substituent, which may have a substituent indicates the heterocyclic group which may have an aralkyl group or a substituted group, and R ⁶³ R ⁶⁴
May combine with each other to form a ring. R ⁶⁵ represents a hydrogen atom, a lower alkyl group, an aryl group which may have a substituent, an aralkyl group which may have a substituent, a lower alkoxy group, or a halogen atom. R ⁶⁵ and R ⁶¹ and R ⁶⁵
And R ⁶² may combine with each other to form a ring. )

Embedded image (Wherein, R ^{71 to} R ⁷⁴ may be the same or different and represent a lower alkyl group or an aryl group which may have a substituent; Ar ⁵ and Ar ⁷ may be the same or different; And a phenyl group which may be substituted with one or more selected from the group consisting of a lower alkoxy group, an aryloxy group and a halogen atom, and Ar ⁶ is a group consisting of a lower alkyl group, a lower alkoxy group, an aryloxy group and a halogen atom. And represents a monocyclic or polycyclic aromatic or heterocyclic ring having 4 to 14 carbon atoms which may be substituted with one or more members selected from the group.)

The electrophotographic photoreceptor of the present invention is capable of preventing a change in characteristics due to oxidative deterioration of a photoconductive material or a binder resin, prevention of cracks,
For the purpose of improving mechanical strength, the photosensitive layer preferably contains an antioxidant, an ultraviolet absorber and other additives. As the antioxidant used in the present invention, 2,6
-Di-tert-butylphenol, 2,6-di-te
rt-butyl-4-methoxyphenol, 2-tert
-Butyl-4-methylphenol, 2-tert-butyl-4-methoxyphenol, 2,4-dimethyl-6-
tert-butylphenol, 2,6-di-tert-
Butyl-4-methylphenol, butylated hydroxyanisole, stearyl-propionate-β- (3,5-di-tert-butyl-4-hydroxyphenyl), α-
Tocopherol, n-octadecyl-3- (3 ', 5'
-Di-tert-butyl-4'-hydroxyphenyl)
Monophenolic antioxidants such as propionate, 2,
2'-methylenebis (6-tert-butyl-4-methylphenol), 4,4'-butylidene-bis- (3-
tert-butyl-4-methylphenol), 4,4 '
-Thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,
3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3,5-di-ter
Polyphenols such as [t-butyl-4-hydroxyphenyl) propionate] methane and the like are preferable, and one or more of these can be simultaneously contained in the photosensitive layer.

As the ultraviolet absorber, 2- (5-
Methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-tert-butyl) -2-hydroxyphenyl) benzotriazole, 2- (3-ter
t-butyl-5-methyl-2-hydroxyphenyl)-
5-chlorobenzotriazole, 2- (3,5-di-t
tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-
Benzotriazoles such as amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, phenyl salicylate, and p-tert salicylate
Salicylic acids such as -butylphenyl and salicylic acid-p-octylphenyl are preferred.
More than one species can be simultaneously contained in the photosensitive layer.

Also, an antioxidant and an ultraviolet absorber can be added at the same time. These additives may be added to any layer in the photosensitive layer, but are preferably added to the outermost surface layer, particularly to the charge transfer layer. The antioxidant is preferably 3 to 20% by weight based on the binder resin, and the amount of the ultraviolet absorber is preferably 3 to 20% by weight based on the binder resin. Further, when both the antioxidant and the ultraviolet absorber are added, the addition amount of both components is preferably 5 to 40% by weight based on the binder resin.

Various additives other than the above-mentioned antioxidants and ultraviolet absorbers can be added to the photosensitive layer. For example,
Hindered amine light stabilizers such as bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, antioxidants such as diphenylamine compounds, biphenyl compounds, m-terphenyl, m-di-tert-butyl Examples include plasticizers such as phenyl and dibutyl phthalate, surface lubricants and surfactants such as silicone oils, graft-type silicone polymers and various fluorocarbons, and potential stabilizers such as dicyanovinyl compounds and carbazole derivatives. An undercoat layer having a barrier function, an adhesive function, a function of covering the surface of the support, and the like can be provided between the photosensitive layer and the conductive support prepared as described above. Materials for forming the undercoat layer include aluminum oxide, polyvinyl alcohol, nitrocellulose, casein, gelatin, ethylene-acrylic acid copolymer, polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyamide resin such as nylon, and polyurethane. Resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, and the like. These materials may be used alone, or two or more materials may be mixed and laminated. Further, an undercoat layer in which a metal compound, a metal oxide, carbon, silica, resin powder, and the like are dispersed in a resin can also be used. Further, various pigments, an electron accepting substance, an electron donating substance, and the like can be contained for improving characteristics. The thickness of the undercoat layer is suitably from 0.1 to 5 μm, preferably from 0.5 to 3 μm.

On the surface of the photosensitive layer, an organic thin film such as a polyvinyl formal resin, a polycarbonate resin, a fluorine resin, a polyurethane resin, or a silicon resin, or a thin film composed of a siloxane structure formed by a hydrolyzate of a silane coupling agent is formed. A film may be provided with a surface protective layer, which is preferable because durability of the photoreceptor is improved. This surface protective layer may be provided to improve functions other than the enhancement of durability. As described above, the charge transfer layer contains the 1- (p-diethylaminophenyl) -1,4,4-triphenylbutadiene derivative in which the trans form represented by the formula (I) is at least 60% by weight. A photoreceptor can be obtained.

[0035]

Hereinafter, examples of the electrophotographic photosensitive member according to the present invention will be described in detail along with comparative examples. In addition, the charge transfer agent compound used in Comparative Example 2 is a known compound and is shown in Table 1.

[0036]

[Table 1]

Example 1 On a cylindrical drum made of aluminum having a diameter of 30 mm, polyvinyl butyral was used as a binder resin, and a Bragg angle (2θ ± 0.2 °) 7.4 ° in the CuKα X-ray diffraction spectrum. 3 °, 1
0.6 °, 13.2 °, 15.1 °, 15.7 °, 1
6.1 °, 20.8 °, 23.3 °, 26.3 °, 2
A dispersion of oxytitanium phthalocyanine having a crystal peak at 7.1 ° is applied by dip coating to a thickness of 0.1 μm,
A charge generation layer was formed.

Next, a polycarbonate Z resin (manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a binder resin, 91.0% by weight of a trans form of the formula [I] and a cis form 9.0 of the formula [II] as a charge transfer agent. % By weight of a butadiene compound and 2,6-di-tert-butyl-4-methylphenol as an antioxidant were added to a binder resin / trans-form of formula [I] /antioxidant=1.0/ It was dissolved in chloroform at a weight ratio of 1.0 / 0.1 to prepare a coating solution.

After this coating solution was applied by dip coating, the coating solution was dried at a temperature of 100 ° C. for 1 hour to form a charge transfer layer having a thickness of 20 μm. An electrophotographic photoreceptor was manufactured by the method described above.

Example 2 The trans form of the charge transfer agent of Example 1 was replaced with 91.0% by weight of the trans form of the formula [I] and 9.0% by weight of the cis form of the formula [II]. An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the weight ratio was changed to 13.8% by weight.

Example 3 Transform 83.2 of the charge transfer agent of Example 1 was replaced with 91.0% by weight of the trans form of the formula [I] and 9.0% by weight of the cis form of the formula [II]. An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the weight ratio was changed to 16.8% by weight.

Example 4 The trans-form 68.4 of the charge transfer agent of Example 1 was replaced with 91.0% by weight of the trans-form of the formula [I] and 9.0% by weight of the cis-form of the formula [II]. An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the content was changed to 31.6% by weight and the cis-form was 31.6% by weight.

COMPARATIVE EXAMPLE 1 The charge transfer agent of Example 1 was replaced by 91.0% by weight of the trans form of the formula [I] and 9.0% by weight of the cis form of the formula [II], but by the trans form of 56.9. An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the weight ratio was changed to 43.1% by weight.

Comparative Example 2 In place of the butadiene compound charge transfer agent comprising the trans form of the formula [I] and the cis form of the formula [II] in Example 1, the comparative compound No. 1 of Table 1 was used. Binder resin / Comparative compound no. An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the weight ratio of 1 / antioxidant was 1.0 / 1.0 / 0.1.

The electrophotographic photosensitive members produced in Examples 1 to 4 and Comparative Examples 1 and 2 were subjected to electrophotographic characteristics under the following conditions using a photosensitive drum evaluation apparatus (Model-ELYSIA, manufactured by Trek Japan KK). Was evaluated (dynamic mode characteristics). First, a corona discharge of -5 kV was performed on the photoconductor for 5 seconds. The surface potential at this time was measured (initial potential V01).
Further, charging and discharging were repeated while irradiating light with 300 Lux, and the potential after discharging after 100 cycles was defined as residual potential VR1. Thereafter, charging and discharging were repeated while further irradiating 300 Lux with white light, the residual potential VR2 after 1000 cycles was measured, and the value of | VR2-VR1 | = ΔVR was determined to be a fluctuating potential. The surface potentials at 5 ° C., 25 ° C. and 50 ° C. were measured in the same manner as the above-mentioned initial surface potential measurement, and the charging potential fluctuation ΔVO in an environment of 5 ° C. to 50 ° C. was determined. Table 2 shows the results.

[0046]

[Table 2] VO1: Initial surface potential ΔVO: Difference in fluctuation of surface potential at 5 to 50 ° C. VR1: Initial residual potential (charge elimination is repeated while irradiating 300 Lux of white light, potential after 100 cycles elimination) ΔVR: After 1000 cycles The fluctuating potential obtained by subtracting the initial residual potential from the residual potential IP value: Ionization potential (RIKEN Keiki Co., Ltd. AC
-1)

As can be understood from Examples 1 to 4 in Table 2, in the case where the transformer is contained in an amount of 60% by weight or more, the fluctuation of the charging potential in an environment of 5 to 50 ° C. is suppressed to 20 V or less. , The residual potential fluctuation after 1000 cycles is also 10 V or less. On the other hand, the electrophotographic photosensitive member of Comparative Example 1 could not function as a photosensitive member because the initial and repeated residual potentials increased. Also,
The electrophotographic photosensitive member of Comparative Example 2 had a low initial charging potential,
The fluctuation of the charging potential in an environment of 5 to 50 ° C. is as large as 100 V. As described above, the butadiene compound represented by the formula [I] and the formula [II] contains 60% by weight of the trans form of the formula [I].
If less than 1%, the residual potential sharply rises in a repetition test of 1,000 cycles, whereas 1- (p-diethylaminophenyl) in which the trans form represented by the formula (I) is 60% by weight or more. ) An electrophotographic photosensitive member using a -1,4,4-triphenylbutadiene derivative has a stable film,
It was confirmed that the film was excellent in various characteristics such as high mobility, good sensitivity and low residual potential. This is because the mobility and the ionization potential value differ depending on the content of the trans-form and the cis-form represented by the formula [I] and the formula [II]. It is considered that the influence on the repetition characteristics, such as the increase in the residual potential, became particularly large.

[0048]

As described above, the electrophotographic photoreceptor of the present invention provides an electrophotographic photoreceptor having excellent characteristics for suppressing fluctuations in surface potential and increase in residual potential after repeated use. Things.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Kobayashi 1-4-11 Nishi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Takasago International Co., Ltd. (72) Inventor Mamoru Yamada 1-chome, Nishi-Hachiman, Hiratsuka-shi, Kanagawa No. 4-11 Takasago International Co., Ltd. Research Institute (72) Inventor Yoko Aoki 1-4-11 Nishi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside Takasago International Co., Ltd.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer having at least a charge generating agent, a charge transfer agent and a binder resin formed on a conductive support, wherein the charge transfer agent of the formula [I] is contained in the photosensitive layer. An electrophotographic photoreceptor comprising a trans form and a butadiene compound represented by a cis form of the formula [II], wherein the trans form of the formula [I] is at least 60% by weight of the butadiene compound. Embedded image