JP2003270825A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor containing an arylidene derivative excellent in charge carrier transport characteristic in a photosensitive layer and having high sensitivity, low residual potential, excellent electrostatic charge performance and excellent repetitive characteristics and to provide an image forming apparatus in which an image fog does not occur even when images are repeatedly formed. <P>SOLUTION: An arylidene derivative represented by formula (1) (where R<SP>1</SP>is hydrogen, an alkyl or aryl; R<SP>2</SP>-R<SP>5</SP>are each cyano or alkoxycarbonyl; and X is a condensed polycyclic hydrocarbon) is incorporated into the photosensitive layer of an electrophotographic photoreceptor used in an image forming apparatus. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-sensitivity electrophotographic photoreceptor containing an arylidene derivative having a high charge-transporting ability, and an image for an electrostatic copying machine, a facsimile, a laser beam printer, etc., using the photoreceptor. Forming apparatus

[0002]

2. Description of the Related Art In the above image forming apparatus, various organic photoconductors having sensitivity in the wavelength region of the light source used in the apparatus are used. This organic photoconductor is easier to manufacture than conventional inorganic photoconductors, and has a wide range of choices for photosensitive materials such as charge transport agents, charge generation agents, and binder resins, and has a high degree of freedom in functional design. Therefore, it has been widely used in recent years.

As a compound used as a charge (electron) transfer agent used in an organic photoconductor, a compound represented by the general formula (2) is described in JP-A-2000-314970.

[0004]

[Chemical 4]

(In the formula, R ¹⁰¹ represents a hydrogen atom, an alkyl group or an aryl group, R ¹⁰² and R ¹⁰³ represent a halogen atom, an alkyl group, an alkoxy group, an aralkyl group, an alkylthio group or an aryl group, and a and b are 1 Indicates an integer from ~ 4,
When a is 2 or more, the plurality of R ¹⁰² may be the same or different, and when b is 2 or more, the plurality of R ¹⁰³ may be the same or different. ), An arylidene derivative having a molecular skeleton represented by Further, there is described an electrophotographic photoreceptor in which the arylidene derivative is contained in a single-layer type or laminated type photosensitive layer and used as a charge (electron) transfer agent.

[0006]

However, the general formula
Since the arylidene derivative (2) is not yet sufficient in the charge transport property, the photoreceptor using this compound has insufficient sensitivity to light and the residual potential of the photoreceptor becomes high. This becomes remarkable when images are repeatedly formed. Further, the charging performance is significantly deteriorated due to deterioration of the photoconductor during repeated use. For these reasons, when an image is formed using a conventional photoconductor, image fog is liable to occur, especially during repeated image formation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems and to provide an electrophotographic photoreceptor having high sensitivity, low residual potential, excellent charging performance and excellent repetitive characteristics.

Another object of the present invention is to provide an image forming apparatus in which image fog does not occur even when image formation is repeated.

[0009]

[Means for Solving the Problems] The inventors of the present invention have conducted research to solve the above problems, and among the arylidene derivatives, a compound represented by the general formula (1):

[0010]

[Chemical 5]

(Wherein R ¹ is a hydrogen atom, an alkyl group or an aryl group, R ^{2 to} R ⁵ are cyano groups or alkoxycarbonyl groups, and X is a condensed polycyclic hydrocarbon). The present inventors have completed the present invention by discovering the fact that they have a higher charge transporting property than conventional arylidene derivatives.

That is, the electrophotographic photoreceptor of the present invention is a photosensitive material containing an arylidene derivative represented by the above general formula (1) (hereinafter referred to as arylidene derivative (1)), a charge generating agent and a binder resin. It is characterized by having layers.

Further, the electrophotographic photosensitive member of the present invention has the general formula (1-1) of the arylidene derivative (1):

[0014]

[Chemical 6]

(In the formula, R ^{1 to} R ⁵ are the same as above, and R ⁶ and R ⁷ represent a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group or an alkylthio group,
m and n represent an integer of 1 to 6, and when m is 2 or more, multiple R ⁶
May be the same or different, and when n is 2 or more, multiple R ⁷
May be the same or different. A compound represented by the formula (hereinafter referred to as arylidene derivative (1-1)) or the general formula (1-2):

[0016]

[Chemical 7]

(In the formula, R ^{1 to} R ⁵ are the same as above, and R ⁸ and R ⁹ represent a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group or an alkylthio group,
p and q are integers from 1 to 8, and when p is 2 or more, multiple R ⁸
May be the same or different, and when q is 2 or more, multiple R ⁹
May be the same or different. The compound represented by the formula (hereinafter referred to as arylidene derivative (1-2)) may be contained in the photosensitive layer.

In these arylidene derivatives, since the carbon ring forming the ketone structure is a condensed polycyclic hydrocarbon, the π-electron conjugated system of the molecule is expanded, and the charge transporting property is improved as compared with the conventional arylidene derivative. In particular, arylidene derivatives
(1-1) and the arylidene derivative (1-2) are a π-electron conjugated system having a naphthalenone structure or anthrone structure in the molecule and a π group continuing from a phenyl group at the terminal of the molecule to an azo group, a carbon atom, a carbocycle and an oxo group. Due to the electron-conjugated system, the π-electron conjugated system has a two-dimensional spread, and thus has excellent charge transportability.

From the above, the arylidene derivative (1), particularly the arylidene derivative (1-1) or the arylidene derivative (1-
By using 2) as a charge (electron) transfer material in the electrophotographic photoreceptor, an electrophotographic photoreceptor having high sensitivity and good durability can be obtained.

Since the electrophotographic photoreceptor of the present invention contains the arylidene derivative (1) in the photosensitive layer, it has a high rate of transporting charges (electrons) generated by the charge generating agent and is excellent in photosensitivity. . Furthermore, it is also excellent in charging performance during repeated use. As a result, according to the electrophotographic photoreceptor of the present invention, the residual potential is lower than that when the conventional arylidene derivative is used as a charge transfer agent, and high sensitivity is obtained,
Repeatability is improved.

The image forming apparatus of the present invention has an electrophotographic photosensitive member containing the arylidene derivative (1) in the photosensitive layer and a driving means for driving the photosensitive member in a fixed direction. Further, a charging means, an exposing means, a developing means, and a transferring means are provided in this order along the driving direction of the photoconductor. Therefore, in the image forming apparatus,
It is possible to obtain a good image without image fogging even when the image formation is repeatedly performed.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The arylidene derivative of the present invention
(1), the electrophotographic photosensitive member and the image forming apparatus will be described in detail. <Arylidene derivative (1)> In the general formula (1), the general formula (1-1) and the general formula (1-2), X is a condensed polycyclic hydrocarbon, and specific examples thereof include a pentalene structure, an indene structure, Azlen structure, naphthalene structure, heptalene structure, biphenylene structure, indacene structure, acetylnaphthylene structure, fluorene structure, phenalene structure, phenanthrene structure, anthracene structure, etc. Examples of the skeleton include groups having two bonds at arbitrary two positions. Of the above, the naphthalene structure and the anthracene structure are preferable because the π-electron conjugated system of the quinone derivative (1) is two-dimensionally spread and the compatibility with the resin is excellent.

General formula (1), general formula (1-1) and general formula (1-
Specific examples of the substituents R ^{1 to} R ⁹ defined in 2) are as follows.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl,
Neopentyl, n-hexyl, n-heptyl, n-nonyl, n-
Examples thereof include alkyl groups having 1 to 12 carbon atoms such as decyl, n-undecyl and n-dodecyl. Among them, methyl, ethyl, n-
An alkyl group having 1 to 6 carbon atoms such as propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl is preferable.

As the alkoxy group, for example, methoxy,
Ethoxy, propoxy, isopropoxy, butoxy, t-
Examples thereof include alkoxy groups having 1 to 6 carbon atoms such as butoxy, pentyloxy and hexyloxy.

Examples of the aryl group include aryl groups having 6 to 14 carbon atoms in the aryl moiety such as phenyl, tolyl, xylyl, biphenylyl, o-terphenyl, naphthyl, anthryl and phenanthryl.

As the aralkyl group, for example, benzyl,
Benzhydryl, trityl, phenethyl, 1-phenylethyl, 3-phenylpropyl, 4-phenylbutyl, 5-phenylpentyl, 6-phenylhexyl, etc. have 1 to 6 carbon atoms in the alkyl portion or 6 to 6 carbon atoms in the aryl portion. There is an aralkyl group which is 14.

Examples of the alkylthio group include those in which the alkyl portion is the same as the above, an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.

The above-mentioned aryl group, aralkyl group and condensed polycyclic hydrocarbon may have a substituent, and specific examples thereof include hydroxyalkyl group, alkoxyalkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl group,
Halogen-substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, halogen atom, amino group,
Hydroxy group, optionally esterified carboxyl group, cyano group, etc., the same halogen atom as above,
Examples thereof include an alkyl group, an alkoxy group, an aryl group and an aralkyl group. The substitution position of these substituents is not particularly limited.

Specific examples of such an arylidene derivative include, but are not limited to, general formulas (1-1-1) to
Compound represented by (1-1-32) (hereinafter, arylidene derivative
Describe as (1-1-1) to (1-1-32). ), General formula (1-2-1) ~ (1
-2-32) compound (hereinafter referred to as an arylidene derivative (1
Describe it as -2-1) to (1-2-32). ) And the like. In the formula, Me represents a methyl group, Et represents an ethyl group, i-Pr represents an isopropyl group, t-Bu represents a t-butyl group, and sec-Bu represents a s-butyl group.

[0032]

[Chemical 8]

[0033]

[Chemical 9]

[0034]

[Chemical 10]

[0035]

[Chemical 11]

[0036]

[Chemical 12]

[0037]

[Chemical 13]

[0038]

[Chemical 14]

[0039]

[Chemical 15]

<Electrophotographic Photoreceptor> The electrophotographic photoreceptor of the present invention comprises a supporting substrate and a photosensitive layer containing the arylidene derivative (1), a charge generating agent and a binder resin. As the arylidene derivative (1), any one derivative may be used, or two or more derivatives may be used in combination.

The photosensitive layer includes a single-layer type photosensitive layer and a laminated type photosensitive layer, but any of these can be applied to the present invention.

Of these, the single-layer type photosensitive layer is composed of only a photoconductive layer containing a charge transport agent, a charge generating agent and a binder resin in the same layer. To form the photosensitive layer, a charge generating agent is used as a charge transporting agent (hole transporting agent and electron transporting agent,
Details will be described later. ) And a binder resin are dissolved or dispersed in an appropriate organic solvent to prepare a coating liquid, which is applied on a supporting substrate by a means such as coating and then dried. By dispersing the arylidene derivative (1) as a charge transporting agent in the above coating liquid, a photosensitive layer excellent in charge transporting ability can be formed.

In the present invention, since the arylidene derivative (1) having an electron transporting property is used as the charge transporting agent, a negatively charging type photosensitive layer is obtained. However, when a hole transporting agent is used in combination, it is of a dual charging type or a positive charging type.

The single-layer type photosensitive layer described above has a simple layer structure and is excellent in productivity, can suppress film defects when forming a layer, and can reduce optical interfaces between layers to improve optical characteristics. There are advantages.

On the other hand, the laminated type photosensitive layer is constituted by laminating a charge transport layer containing a charge transport agent and a charge generation layer containing a charge generator on a supporting substrate. Further, a photoconductive layer containing a charge transporting agent together with the charge generating agent may be combined with the charge transporting layer and the charge generating layer. Each layer is CV
It can be formed by a vapor phase growth method such as D method or a method such as coating.

For the laminated photosensitive layer, various combinations are conceivable depending on the order of forming the charge generating layer, the charge transporting layer and the like and the type of the charge transporting agent (hole transporting agent or electron transporting agent) contained in both layers. However, in the present invention, it is necessary that at least one of the charge transport layer and the photoconductive layer contains the electron transporting arylidene derivative (1).

Therefore, specific examples of the laminated type photosensitive layer are as follows. (a) A positive charging type photosensitive layer in which a charge generation layer or a photoconductive layer is formed on a supporting substrate, and a charge transport layer containing the arylidene derivative (1) is laminated thereon. (b) A negative charging type photosensitive layer in which a charge transporting layer containing the arylidene derivative (1) is formed on a supporting substrate, and a charge generating layer or a photoconductive layer is laminated thereon. (c) A laminated photosensitive layer in which a charge generation layer or a photoconductive layer is formed on a supporting substrate, and a charge transport layer containing the arylidene derivative (1) and a hole transport agent is laminated thereon. (d) A laminated photosensitive layer in which a charge transport layer containing the arylidene derivative (1) and a hole transport agent is formed on a supporting substrate, and a charge generation layer or a photoconductive layer is laminated thereon.

The photosensitive layers of the above (c) and (d) are composed of the kind of hole transporting agent contained in the charge transporting layer and the arylidene derivative.
Depending on the compounding ratio of (1) and the hole transfer agent, it is determined to be positive, negative or both charging types.

A charge generation layer, a charge transport layer, and a photoconductive layer can be added to the layer structures (a) to (d) as required. At this time, it is sufficient that at least one of the charge transport layer and the photoconductive layer contains the arylidene derivative (1).

Of the above, the charge transport layer and the photoconductive layer are generally much thicker than the charge generation layer. For this reason, when these layers are formed on the outermost surface, the electrical characteristics do not easily change even if the photosensitive layer is worn during repeated image formation. Therefore, in the laminated photosensitive layer, the above (a) or
The configuration of (c) is preferable. However, this is not the case when a resin layer or an inorganic layer for the purpose of protecting the photosensitive layer is formed on the outermost surface of the photoreceptor.

The above-mentioned laminated type photoreceptor has a charge generation,
Since the functions such as charge transport are separated in each layer, there is an advantage that waste of constituent materials is small and sensitivity is easily improved.

Since the electrophotographic photoreceptor of the present invention contains the arylidene derivative (1) in the photosensitive layer, the residual potential of the photoreceptor is low as compared with the case where the conventional arylidene derivative (1) is used. , The sensitivity is improved.

The materials and constitution of the electrophotographic photosensitive member of the present invention will be described below. (Charge Generating Agent) The charge generating agent used in the single-layer type or laminated type photosensitive layer is, for example, a powder of an inorganic photoconductive material such as an amorphous inorganic material [eg, a-silicon, a-carbon, etc.], Metal-free phthalocyanine, metal (eg titanium,
Copper, aluminum, iron, cobalt, nickel, indium, gallium, tin, zinc, vanadium, etc.) or various oxides such as phthalocyanine coordinated with a metal oxide (TiO, etc., which is an oxide of the above metals) Phthalocyanine pigments composed of crystals, azo pigments, bisazo pigments, perylene pigments, anthanthrone pigments, indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments,
Various conventionally known pigments such as dithioketopyrrolopyrrole pigments can be used.

The charge generating agents may be used alone or in combination of two or more so that the photosensitive layer has sensitivity in the wavelength region of exposure. (Electron Transfer Material) In the electrophotographic photosensitive member of the present invention, other conventionally known electron transfer material may be contained in the photosensitive layer together with the arylidene derivative (1) of the present invention which is an electron transfer material.

As a specific example, a benzoquinone compound,
Diphenoquinone compounds [eg 2,6-dimethyl-2 ', 6'
-t-butylbenzoquinone, etc.), naphthoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, fluorenone compounds (eg 2,4,7-trinitro-9-fluorenone etc.) , Dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride,
2,4,7-Trinitrofluorenone imine compounds, ethylated nitrofluorenone imine compounds, tryptoanthrin compounds, tryptoanthrin imine compounds, azafluorenone compounds, dinitropyridquinazoline compounds, thioxanthene compounds , 2-phenyl-1,4-benzoquinone compound, 2-phenyl-1,4-naphthoquinone compound, 5,12-naphthacenequinone compound, α-cyanostilbene compound, 4′-nitrostilbene compound, and Examples thereof include electron transfer agents such as salts of anion radicals and cations of benzoquinone compounds.

These charge transfer agents can be used alone or in combination of two or more kinds. (Hole Transporting Agent) As the hole transporting agent, any of various conventionally known hole transporting compounds can be used. Specific examples include benzidine compounds, phenylenediamine compounds, naphthylenediamine compounds, phenanthrylenediamine compounds, oxadiazole compounds [eg 2,5-di (4-methylaminophenyl) -1,3 , 4-oxadiazole, etc.], styryl compounds [eg 9- (4-diethylaminostyryl) anthracene], distyryl compounds, carbazole compounds [eg poly-N-vinylcarbazole], pyrazoline compounds [eg 1-
Phenyl-3- (p-dimethylaminophenyl) pyrazolin, etc.], hydrazone compounds [eg diethylaminobenzaldehyde diphenylhydrazone, etc.], triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, Thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, butadiene compounds, pyrene-hydrazone compounds, acrolein compounds, carbazole-hydrazone compounds,
Quinoline-hydrazone compounds, stilbene compounds,
Examples include stilbene-hydrazone compounds, diphenylenediamine compounds and organic polysilane compounds.

The above hole transfer agents may be used alone or in combination of two or more. Further, when using a hole transporting agent having film-forming properties such as polyvinylcarbazole, the binder resin is not always necessary. (Binder resin) Examples of the binder resin include styrene-based polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers,
Acrylic polymer, styrene-acrylic copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, polyamide, polycarbonate, polyarylate , Thermoplastic resins such as polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, silicone resin, epoxy resin, phenol resin,
Examples thereof include urea resins, melamine resins, unsaturated polyesters, alkyd resins, polyurethanes, other crosslinkable thermosetting resins, and photocurable resins such as epoxy-acrylate and urethane-acrylate. These can be used alone or in combination of two or more.

Among the hole transport agents exemplified above, poly-N
-When a high molecular weight hole transport material such as vinylcarbazole or an organic polysilane compound is used, the compound can also function as a binder resin, and the usual binder resin exemplified above can be omitted. (Other materials) In the photosensitive layer, in addition to the above-mentioned respective components, various conventionally known additives such as antioxidants, radical scavengers, singlet quenchers, in addition to the above-mentioned respective components, Deterioration inhibitors such as UV absorbers, softeners,
A plasticizer, a surface modifier, a filler, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor and the like can be added. Further, in order to improve the sensitivity of the photosensitive layer, a known sensitizer such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generating agent. (Supporting Substrate) As the supporting substrate on which the photosensitive layer is formed, various conductive materials can be used,
For example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass or other metal simple substance, the metal is a vapor deposited or laminated plastic material, Examples thereof include glass coated with aluminum iodide, tin oxide, indium oxide and the like.

The shape of the supporting substrate may be any of a sheet, a belt, a drum, etc., depending on the structure of the image forming apparatus used, and whether the substrate itself is electrically conductive,
Alternatively, it suffices if the surface of the substrate has conductivity. Further, the supporting substrate is preferably one having sufficient mechanical strength when used. (Formation of photosensitive layer) The photosensitive layer is formed, for example, by a plasma CVD method,
It can be formed by various conventionally known vapor deposition methods such as a chemical vapor deposition method such as photo CVD method, a sputtering method, a vacuum vapor deposition method, a physical vapor deposition method such as an ion plating method, or a coating method.

Among these, the coating method may be formed as follows.

In the single-layer type photosensitive layer, the charge generating agent is added in an amount of 0.1 to 50 parts by weight, particularly 0.5 to 100 parts by weight, based on 100 parts by weight of the binder resin.
In the proportion of 30 parts by weight, the electron transfer agent is 5 to 100 parts by weight, especially 10 parts by weight.
It is preferable that each of them is contained in a proportion of 80 parts by weight. When the hole transport material is contained, the binder resin 100
The content is preferably 5 to 500 parts by weight, more preferably 25 to 200 parts by weight, based on parts by weight. Further, the content ratio of the electron transfer agent is the content ratio of the arylidene derivative (1) when only the arylidene derivative (1) is used, and when the arylidene derivative (1) is used in combination with another electron transfer agent. It is the total content ratio of both.

When the electron transfer agent and the hole transfer agent are used in combination, the total amount thereof is 20 to 500 with respect to 100 parts by weight of the binder resin.
Weight parts, especially 30 to 200 weight parts are preferred.

The thickness of the single-layer type photosensitive layer is 5 to 100 μm, particularly 10
It is preferably about 50 μm.

In the charge-generating layer of the laminated type photosensitive layer, the charge-generating agent is added in an amount of 5 to 1000 with respect to 100 parts by weight of the binder resin.
It is preferable to contain it in an amount of 30 parts by weight, especially 30 to 500 parts by weight. In the case where the photoconductive layer contains a charge transfer material in the charge generation layer, 100 parts by weight of the binder resin, 1 to 200 parts by weight, particularly 5 to 100 parts by weight when the electron transfer material is contained. It is preferable to contain it in a ratio of parts. When the hole transfer agent is contained, 1 to 500 parts by weight of the hole transfer agent, particularly
It is preferably contained in a proportion of 25 to 200 parts by weight. When the electron transfer agent and the hole transfer agent are used in combination, the total amount thereof is preferably 10 to 500 parts by weight, and particularly preferably 30 to 200 parts by weight, based on 100 parts by weight of the binder resin.

In the charge transport layer, the binder resin 100
1 to 250 parts by weight, especially 5 to 1 part by weight of the electron transfer agent, relative to parts by weight.
When the hole transfer agent is contained at a ratio of 50 parts by weight, the hole transfer agent is preferably contained at a ratio of 10 to 500 parts by weight, particularly 25 to 200 parts by weight.

Here, the content ratio of the electron transfer agent is such that when only the arylidene derivative (1) is used, the content ratio of the arylidene derivative (1) and when the arylidene derivative (1) is used in combination with another electron transfer agent. Is the total content of both.

When the electron transfer agent and the hole transfer agent are used in combination, the total amount thereof is 10 to 500 with respect to 100 parts by weight of the binder resin.
Weight parts, especially 30 to 200 weight parts are preferred.

The thickness of the laminated photosensitive layer is 0.01 for the charge generation layer.
~ 5μm, especially about 0.1 ~ 3μm, the charge transport layer 2 ~ 100μm,
Particularly, about 5 to 50 μm is preferable.

The characteristics of the photoconductor are provided between the single-layer or laminated organic photosensitive layer and the conductive substrate, or between the charge generation layer and the charge transport layer constituting the laminated photosensitive layer. You may form an intermediate | middle layer, a protective layer, and a barrier layer in the range which does not interfere.

When each layer constituting the photoconductor is formed by a coating method, the charge generating agent, charge transporting agent, binder resin and the like exemplified above may be used together with the above-mentioned organic solvent such as tetrahydrofuran in a known method. For example, a coating solution may be prepared by dispersing and mixing using a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser, etc., and the coating solution may be applied and dried by a known means.

Examples of the organic solvent for preparing the coating liquid include alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, benzene, toluene and xylene. Aromatic hydrocarbons, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, cyclohexanone 1 or 2 such as ketones, ethyl acetate, esters such as methyl acetate, dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide, etc. Or more, and the like.

Further, in order to improve the dispersibility of the charge transporting agent or the charge generating agent and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent or the like may be added to the coating liquid. <Image Forming Apparatus> FIG. 1 schematically shows an example of the image forming apparatus embodied in the present invention. Reference numeral 1 denotes the above-mentioned electrophotographic photosensitive member (a photosensitive layer 11 is formed on a supporting substrate 10), and its shaft center 13 is connected to a driving means 14 via a gear and a pulley, and is in one direction ( It rotates at a constant speed in the direction of arrow A). Around the photoreceptor 1, the main charging means is arranged along the driving direction, that is, the rotation direction.
2, exposure means 3, developing means 4, and transfer means 5 are provided in this order. Further, as shown in FIG. 1, a separating means 6, a charge removing means 7, and a cleaning means 9 may be provided as needed.

Further, the image forming apparatus of the present invention is provided with the fixing means 12 for fixing the toner image to the transfer medium 8 onto which the toner image has been transferred.

In forming an image, the surface of the photoreceptor 1 is first uniformly charged by the charging means 2. Next, the surface of the photoconductor 1 is exposed by the exposure means 3 along the exposure axis 31, and an electrostatic latent image corresponding to the original image is formed. Since the image forming apparatus uses the electrophotographic photosensitive member described above, the potential (hereinafter, referred to as surface potential) of the photosensitive member 1 with respect to the ground portion quickly drops to the value of the bright potential. Then, the non-image area which has not been exposed is stabilized at the value of the dark potential with almost no decrease in the surface potential.

Thereafter, the developing means 4 develops the toner by adhering it to the portion corresponding to the electrostatic latent image. Then, the transfer medium conveyed (in the direction of arrow B) by the transfer means 5.
The toner image on the surface of the photoconductor 1 is transferred onto the surface 8. The transfer medium 8 after the transfer is separated from the photoconductor 1 by the separating unit 6, and then fixed by the fixing unit 12 with toner.

After the transfer, the photoconductor 1 cannot be completely transferred to the transfer medium 8.
The toner remaining on the surface is removed by the cleaning means 9. After that, the residual potential on the surface of the photoconductor 1 is removed by the discharging means 7.
It is removed by the static elimination light 71 from and is charged again by the charging means 2.

As the charging means 2, a conventionally known method, for example, a method of applying a high voltage to a charge wire provided close to the surface of the photosensitive member 1 to perform corona discharge, or a charging member such as a conductive roller or a charging brush is used. A method of contacting the surface of the photoconductor 1 to give a charge to the photoconductor 1 or the like is applied. In order to keep the surface potential at the main charging portion constant, a method of bringing a charging member into contact with the surface of the photoreceptor 1 or providing a grid electrode between the charge wire of the main charger and the photoreceptor 1 for corona discharge It is preferable to use the method of performing.

The main charging voltage applied from the charging means 2 to the photosensitive member 1 varies depending on the characteristics of the photosensitive member 1 and the toner, developing conditions, etc., but in the case of a general positive charging type photosensitive member, the surface of the photosensitive member 1 is It may be set so that the potential difference with respect to the ground part of + 300V to + 1000V.

As the exposure means 3, a laser beam having a wavelength at which the photoconductor 1 is sensitive is generally used. Specifically, light having a wavelength at which the charge generating agent absorbs may be used.
For example, when a phthalocyanine pigment is used as the charge generating agent, a laser beam having a wavelength of about 600 nm to 850 nm, a perylene pigment of about 400 to 600 nm, and a bisazo pigment of about 600 to 700 nm is used.

The exposure dose should be set so that the bright potential is as low as possible. Specifically, the light potential of the photoconductor 1 has the same polarity as the potential with respect to the ground portion of the main charged photoconductor 1, and in addition, preferably 0 to 50 V, more preferably 0 to 10 V, exposure The amount should be set.

As the developing means 4, a conventionally known contact or non-contact developing device can be used, and either a dry method or a wet method may be used. The developer used in the developing means 4 may be either a one-component system or a two-component system.

As the transfer means 5, any conventionally known contact transfer or non-contact transfer method can be applied. Specifically, a transfer voltage is applied to the photoconductor 1 via the transfer medium 8 by a charger, a roller, a brush, a plate, or the like.

As the separating means 6, similar to the charging means 2,
Corona discharge using a charge wire, one using a conductive roller, and the like can be used, and among these, corona discharge is preferably used. The separation voltage applied to the photoconductor 1 by the separation means 6 is generally alternating current.

When the charge eliminating means 7 is provided, conventionally known charge eliminating lamps such as an LED array and a fluorescent tube can be used. The charge-eliminating lamp may be one that emits a light having a wavelength at which the photoconductor 1 has a sensitivity and emitting a sufficient amount of light to remove residual charges on the surface of the photoconductor 1.

When the cleaning means 9 is provided, it is possible to use a conventionally well-known mechanism such as a blade system, a fur brush system, a roller cleaning system, etc., which has a simple toner removal efficiency.

As the fixing means 12, conventionally known heat fixing, pressure fixing, heat pressure fixing, flash fixing or the like may be used.

[0087]

EXAMPLES The present invention will be described below based on Examples and Comparative Examples. Example 1 3.5 parts by weight of an X-type metal-free phthalocyanine as a charge generating agent, and a general formula (4) as a hole transporting agent:

[0088]

[Chemical 16]

70 parts by weight of a distyryl compound represented by: 40 parts by weight of an arylidene derivative (1-1-24) as an electron transfer agent,
0.1 part by weight of silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent and general formula as a binder resin
(Five):

[0090]

[Chemical 17]

100 parts by weight of a polycarbonate (viscosity average molecular weight 30,000) consisting of repeating units represented by: was dissolved and dispersed in 450 parts by weight of tetrahydrofuran as a solvent with an ultrasonic disperser to prepare a coating liquid for the photoconductive layer. did. Then, this coating solution was applied onto an aluminum tube with a fluororesin blade and dried at 110 ° C for 40 minutes to give a film thickness of 2
A single-layer type photoreceptor of Example 1 was manufactured by forming a photosensitive layer of 5 μm. [Comparative Example 1] An arylidene derivative (1-1
-24) instead of general formula (2-1):

[0092]

[Chemical 18]

A single-layer type photoreceptor of Comparative Example 1 was produced in the same manner as in Example 1 except that the compound represented by [Comparative Example 2] An arylidene derivative (1-1
-24) instead of general formula (2-2):

[0094]

[Chemical 19]

A single-layer type photoreceptor of Comparative Example 2 was prepared in the same manner as in Example 1 except that the compound represented by Example 2 3.5 parts by weight of Y-type titanyl phthalocyanine as a charge generating agent, a general formula (6):

[0096]

[Chemical 20]

2 parts by weight of the bisazofluorene pigment represented by: and the compound 5 represented by the above general formula (4) as a hole transfer agent.
0 parts by weight, an arylidene derivative (1-1-2
4) 40 parts by weight, 0.1 part by weight of silicone oil (KF-96-50CS manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent, and general formula (7) to general formula (9) as a binder resin:

[0098]

[Chemical 21]

Polycarbonate composed of repeating units represented by
(7): 0.3%, General formula (8): 15%, General formula (9): 84.3%. Dissolve 100 parts by weight of viscosity average molecular weight of 5,000) in 750 parts by weight of tetrahydrofuran as a solvent with an ultrasonic disperser.
It was dispersed to prepare a coating liquid for the photoconductive layer. Then, this coating solution was applied onto an aluminum tube with a fluororesin blade and dried at 110 ° C. for 40 minutes to form a photosensitive layer having a film thickness of 25 μm, and a single-layer type photoreceptor of Example 2 was produced. did. [Comparative Example 3] An arylidene derivative (1-1
-24) was replaced with the compound represented by the general formula (2-1), and a single-layer type photoreceptor of Comparative Example 3 was produced in the same manner as in Example 2. [Comparative Example 4] An arylidene derivative (1-1
-24) was used instead of the compound represented by the general formula (2-2), and a single-layer type photoreceptor of Comparative Example 4 was produced in the same manner as in Example 2. [Example 3] 1 part by weight of Y-type titanyl phthalocyanine as a charge generating agent was mixed with ethyl cellosolve 39 as a dispersion medium.
It was added to parts by weight and was subjected to primary dispersion using an ultrasonic disperser. To this dispersion was further added a solution prepared by dissolving 1 part by weight of polyvinyl butyral (BM-1 manufactured by Sekisui Chemical Co., Ltd.) as a binder resin in 9 parts by weight of ethyl cellosolve, and again using an ultrasonic disperser. Secondary dispersion was carried out to prepare a coating liquid for the charge generation layer in the laminated photosensitive layer. Next, this coating solution was applied onto a φ30 alumite tube using a fluororesin blade and dried at 110 ° C. for 5 minutes to form a charge generation layer having a film thickness of 0.5 μm.

Next, as a binder resin, 95 parts by weight of a polycarbonate (viscosity average molecular weight 30,000) consisting of the repeating unit of the above general formula (5) and a polyester resin (RV manufactured by Toyobo Co., Ltd.) are used.
200) 5 parts by weight, 60 parts by weight of the distyryl compound of the above general formula (4) as a hole transfer agent and 5 parts by weight of an arylidene derivative (1-1-24) as an electron transfer agent, and 800 parts by weight of tetrahydrofuran as a dispersion medium. And mixed and dispersed to obtain a coating liquid for the charge transport layer. Then, this coating solution is applied onto the charge generation layer using a fluororesin blade,
The laminate was dried at 30 ° C. for 30 minutes to form a charge transport layer having a film thickness of 30 μm, and the laminated type photoreceptor of Example 3 was produced. [Comparative Example 5] An arylidene derivative (1-1
-24) was replaced with the compound represented by the above general formula (2-1), and in the same manner as in Example 3, a multi-layer type photoreceptor of Comparative Example 5 was produced. [Comparative Example 6] An arylidene derivative (1-1
-24) was replaced with the compound represented by the above general formula (2-2), and in the same manner as in Example 3, a laminated type photoreceptor of Comparative Example 6 was produced. <Evaluation of Photoreceptor> The single-layer photoreceptors obtained in Examples 1 and 2 and Comparative Examples 1 to 4 were mounted on an electrostatic copying machine [FS-1000 + modified machine manufactured by Kyocera Corp.] and initially After setting, the surface potential upon charging and the bright potential after exposure were measured. Next, the charging-exposure-static elimination operation was performed continuously for 2 hours to measure the surface potential during charging, and the difference from the initial measured value was obtained.

After that, the image was output, and the image fog on the blank portion was visually evaluated according to the following criteria.

A: No image fogging occurred.

◯: Fogging of the image was slightly recognized, but it was at a level where there was no practical problem.

Δ: Image fogging was at a level that could be recognized at a glance.

X: The occurrence of image fogging was remarkable.

Further, the laminated type photoreceptors obtained in Example 3 and Comparative Examples 5 to 6 were used as electrostatic copying machines [LBP-450 manufactured by Canon Inc.].
[Remodeled machine] and evaluated in the same manner as above.

The electrostatic copying machine was set as follows.・ Charging: Use a scorotron (initial surface potential of about 450V) for a single-layer photoconductor and a charging roller (initial surface potential of about -650V) for a layered photoconductor, and experiment without adjusting the initial machine settings. Was done. ) ・ Exposure: Laser light ・ Development: Reverse development ・ Transfer: Transfer roller ・ Cleaning: Cleaning blade method ・ Electrification: Elimination lamp (LED) ・ Separation: Charge wire ・ Fixing: Thermal pressure fixing The above electrical characteristics and image evaluation results Shown in Table 1.

[0108]

[Table 1]

From Table 1, it can be seen that the photoconductor of Example 1 has a low bright potential remaining on the surface of the photoconductor after exposure and a small decrease in the surface potential after 2 hours of operation, so that a good image without image fog was obtained. . Comparative Examples 1-2 in which only the electron transfer material of Example 1 was changed
The photoconductor of No. 1 has a higher bright potential than the photoconductor of Example 1, and the decrease in surface potential after the operation for 2 hours is large, so that the occurrence of image fogging was observed.

Further, in the photoconductor of Example 2, the bright potential remaining on the photoconductor surface after exposure was low, and the decrease of the surface potential after the operation for 2 hours was small, so that a good image without image fog was obtained. The photoconductors of Comparative Examples 3 to 4 in which only the electron transfer agent of Example 2 was changed had a bright potential higher than that of the photoconductor of Example 2, and the surface potential drop after the operation for 2 hours was large, so that the occurrence of image fogging occurred. Admitted.

Further, since the photoconductor of Example 3 has a low bright potential remaining on the photoconductor surface after exposure and a small decrease in the surface potential after the operation for 2 hours, a good image without image fog was obtained. The photoconductors of Comparative Examples 5 to 6 in which only the electron transfer agent of Example 3 was changed had a bright potential higher than that of the photoconductor of Example 3, and the surface potential drop after the operation for 2 hours was large, so that the occurrence of image fogging occurred. Admitted.

[0112]

INDUSTRIAL APPLICABILITY As described in detail above, the electrophotographic photoreceptor of the present invention contains the arylidene derivative (1) in the photosensitive layer, and therefore is excellent in charge transportability, photosensitivity and charging performance. As a result, the electrophotographic photoreceptor of the present invention has a lower residual potential, higher sensitivity, and improved repetitive properties than those obtained when a conventional arylidene derivative is used as a charge (electron) transfer agent.

Since the image forming apparatus of the present invention uses the electrophotographic photosensitive member containing the arylidene derivative (1) in the photosensitive layer, it is possible to obtain a good image without image fog even when the image formation is repeated.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention.

Claims (3)

[Claims] 1. A compound represented by the general formula (1): (In the formula, R ¹ is a hydrogen atom, an alkyl group or an aryl group,
R ^{2 to} R ⁵ are cyano groups or alkoxycarbonyl groups, and X is a condensed polycyclic hydrocarbon. An electrophotographic photosensitive member having a photosensitive layer containing an arylidene derivative represented by the formula (4), a charge generating agent and a binder resin. 2. The arylidene derivative is represented by the general formula (1-
1): [Chemical 2] (In the formula, R ^{1 to} R ⁵ are the same as above, R ⁶ and R ⁷ represent a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group or an alkylthio group, and m and n are 1
When R is ⁶ or more, a plurality of R ⁶ may be the same or different, and when n is 2 or more, a plurality of R ⁷ may be the same or different. ) Or general formula (1-2): (In the formula, R ^{1 to} R ⁵ are the same as above, R ⁸ and R ⁹ represent a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group or an alkylthio group, and p and q are 1
When p is 2 or more, a plurality of R ⁸ may be the same or different, and when q is 2 or more, a plurality of R ⁹ may be the same or different. 2. The electrophotographic photosensitive member according to claim 1, which is represented by: 3. The electrophotographic photosensitive member according to claim 1, and a driving unit that drives the photosensitive member in a fixed direction, and a charging unit, an exposing unit, a developing unit, along the driving direction of the photosensitive member,
An image forming apparatus characterized in that transfer means are provided in this order.