JPH09151182A - Dibenzofurandiamine derivative and electrophotographic photoreceptor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new dibenzofurandiamine derivative excellent in electron charge transporting ability and stability and suitable as a positive hole transporting agent, etc., in electrophotographic photoreceptor, solar cell, electroluminescence element, etc. SOLUTION: This compound is represented by formula I [R<1> to R<5> are each a halogen, a (substituted)alkyl, a (substituted)alkoxy, a (substituted)aryl or (substituted)aralkyl; (a), (b), (c) and (d) are each 0-5; (e) is 0-6], e.g. N,N,N',N'- tetra(m-tolyl)-3,7-dibenzofurandiamine. Furthermore, the compound of formula I is obtained by reacting, e.g. 3,7-dibenzofurandiamine of formula II with 3- iodotoluene of formula III at a molar ratio of 1:4 in a solvent such as nitrobenzene in the presence of a catalyst such as potassium carbonate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel dibenzofurandiamine derivative suitably used as a charge transport material (hole transport material) and electrophotography used in an image forming apparatus such as an electrostatic copying machine or a laser printer. Regarding the photoconductor.

[0002]

Conventionally, various organic compounds such as carbazole-based compounds, oxadiazole-based compounds, pyrazoline-based compounds, hydrazone-based compounds, stilbene-based compounds, phenylenediamine-based compounds, and benzidine-based compounds have been used as charge transfer agents. It has been known.

Electrophotographic photoreceptors using these organic compounds, that is, organic photoreceptors, include single-layer photoreceptors in which a charge transport agent is dispersed in a binder resin together with a charge generating agent,
There is a multi-layer type photoreceptor including a charge transport layer in which a charge transport agent is dispersed in a binder resin and a charge generation layer in which a charge generator is dispersed in a binder resin. These organic photoconductors are easier to manufacture than inorganic photoconductors using inorganic semiconductor materials, and there are various options for photoconductor materials such as charge transport agents, charge generation agents, and binder resins. The flexibility of functional design is high and it has been widely used in recent years.

Typical examples of the above charge transfer agent include m-phenylenediamine derivatives represented by the following general formula (2).

[0005]

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(In the formula, R ^A , R ^B , R ^C and R ^D are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an aryl group.)

[0007]

The above m-phenylenediamine derivative (2) has excellent charge transporting ability,
There is a problem that the chemical stability is insufficient. In particular, the m-phenylenediamine derivative (2) becomes a highly reactive singlet excited state upon irradiation with light, causing a photochemical reaction to deteriorate. As a result, there arises a problem that the charge transport ability is lowered. This is the HOMO level (Highest Occupied Molecular) related to charge transport.
Orbital (highest occupied level) electrons are localized at the carbon atoms at the 4th and 6th positions of the benzene ring that make up the central skeleton of the molecule, which increases the chemical reactivity of this part. is there.

Therefore, an electrophotographic photosensitive member using the above-mentioned m-phenylenediamine derivative (2) as a charge transport material is
By repeating the steps of charging, exposing and discharging, there arise problems such as a decrease in sensitivity, an increase in charge amount, and insufficient durability. Further, when the m-phenylenediamine derivative (2) is used as a charge transport agent, there is a problem that the abrasion resistance of the photosensitive layer is insufficient.

Therefore, an object of the present invention is to provide a novel compound which is excellent in charge transporting ability and is also excellent in chemical stability particularly when irradiated with light. Another object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity, little deterioration upon repeated exposure, and excellent abrasion resistance.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above-mentioned problems, and as a result, the general formula (1)
:

[0011]

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(Wherein R ¹ , R ² , R ³ , R ⁴ and R
⁵ are the same or different, a halogen atom, an alkyl group,
An alkoxy group, an aryl group or an aralkyl group is shown.
The alkyl group, alkoxy group, aryl group and aralkyl group may have a substituent. a, b, c and d
Are the same or different and each represents an integer of 0 to 5, and e represents an integer of 0 to 6. When a to e are 2 or more, the respective substituents may be different from each other. The dibenzofurandiamine derivative represented by) has a large conjugated dibenzofuran in the central skeleton of the molecule, so that the range of existence of electrons at the HOMO coordinate position is larger than that of the m-phenylenediamine derivative (2). Has a good mobility and has a better charge transporting ability, and it is chemically reactive like the central benzene ring in the m-phenylenediamine derivative (2) due to the delocalization of electrons at the HOMO level. The present invention has been completed by discovering a new fact that a portion having a high temperature is eliminated and the chemical stability is particularly excellent at the time of light irradiation.

In the dibenzofurandiamine derivative (1) of the present invention, the distribution of electrons becomes flat due to the delocalization of electrons in the HOMO position, so that the dibenzofurandiamine derivative (1) (charge-transporting agent) is used. When it is contained in the photosensitive layer together with the charge generating agent, the interaction with the charge generating agent, that is, the charge (particularly holes) generated by the charge generating agent
The action of pulling out is strengthened. Furthermore, since the central skeleton of the dibenzofurandiamine derivative (1) of the present invention is dibenzofuran, which has a large conjugated system and is rigid, by using such a derivative (1) as a charge transfer agent, the charge generation of the charge generating agent can be improved. It is possible to obtain an electrophotographic photoreceptor having high efficiency, excellent sensitivity, little deterioration upon repeated exposure, that is, high durability against exposure, and excellent abrasion resistance of the photosensitive layer.

That is, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate,
The photosensitive layer contains a dibenzofurandiamine derivative represented by the general formula (1). Furthermore, when the photosensitive layer is a single-layer type photosensitive layer containing at least a charge generating agent and an electron transporting agent, the sensitivity of the photoreceptor can be further improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION First, the dibenzofurandiamine derivative (1) of the present invention will be described in detail. Substituent R ¹
Examples of the halogen atom corresponding to ~ R ⁵ include fluorine, chlorine, bromine, iodine and the like. The alkyl group has, for example, 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-pentyl and n-hexyl.
The base is given. Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, t
Examples thereof include butoxy, n-pentyloxy, and n-hexyloxy groups having 1 to 6 carbon atoms. Examples of the aryl group include groups such as phenyl, naphthyl, anthryl and phenanthryl. As an aralkyl group,
Examples include groups such as benzyl, benzhydryl, phenethyl and trityl. The alkyl group may be substituted with a halogen atom or the like, and the alkoxy group, the aryl group and the aralkyl group may be substituted with a halogen atom, an alkyl group or the like. The number of substituents which may be substituted on the alkyl group, the alkoxy group, the aryl group and the aralkyl group and the substitution position thereof are not particularly limited.

When the symbols a to e defining the number of the above substituents R ^{1 to} R ⁵ are 2 or more, the respective substituents may be different from each other. That is, for example, a symbol a indicating the number of substituents R ¹
When 2 is 2, one of the phenyl groups substituting the nitrogen atom of the dibenzofurandiamine derivative (1) includes a methyl group and an ethyl group, an n-propyl group and a phenyl group, a t-butyl group and chlorine, and the like. Different groups may be substituted.

Dibenzofurandiamine derivative of the present invention
Specific examples of (1) include compounds represented by the following formulas (1-1) to (1-8).

[0018]

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[0019]

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[0020]

[Chemical 6]

Dibenzofurandiamine derivative of the present invention
The synthesis method of (1) will be described by taking the dibenzofurandiamine derivative represented by the above formula (1-1) as an example. Reaction process formula (I):

[0022]

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That is, a dibenzofurandiamine derivative
(1-1) is a starting material 3,7-dibenzofurandiamine (3) and 3-
Iodotoluene is used in a ratio of 1: 4 (molar ratio), and this starting material is added to a solvent such as nitrobenzene together with a catalyst such as potassium carbonate or copper and stirred, and the mixture is stirred under an atmosphere of an inert gas such as nitrogen or argon. It is obtained by refluxing at.

Next, the electrophotographic photoreceptor of the present invention will be described in detail. The electrophotographic photoreceptor of the present invention has the general formula
A photosensitive layer containing one or more dibenzofurandiamine derivatives represented by (1) is provided on a conductive substrate. The photosensitive layer includes a so-called single-layer type photosensitive layer and a laminated type photosensitive layer, and the present invention is applicable to both of them.

The single-layer type photosensitive layer has a single photosensitive layer provided on a conductive substrate, and the photosensitive layer contains at least a charge generating agent and a dibenzofurandiamine derivative (1) as a charge transporting agent. It is composed of a binder resin containing. The photoreceptor having a single-layer type photosensitive layer, that is, the single-layer type photoreceptor is applicable to both positive charging and negative charging, but it is particularly preferable to use the positive charging type.

The single-layer type electrophotographic photoconductor of the present invention has a significantly lower residual potential of the photoconductor than the conventional single-layer type electrophotographic photoconductor and has improved sensitivity. Furthermore, when the photosensitive layer of the single-layer type electrophotographic photoreceptor of the present invention further contains an electron transfer agent, transfer of electrons between the charge generation agent and the hole transfer agent can be efficiently performed, The sensitivity of the photoconductor is further improved.

The laminated type photosensitive layer comprises at least a charge generation layer and a charge transport layer provided in this order on a conductive substrate, and the charge transport layer is represented by the general formula (1) as a charge transport agent. It contains the dibenzofurandiamine derivative represented. On the contrary, the charge transport layer may be formed on the conductive substrate, and the charge generation layer may be formed thereon.

The laminated electrophotographic photoreceptor of the present invention has a greatly reduced residual potential and improved sensitivity as compared with the conventional laminated electrophotographic photoreceptor. Further, the dibenzofurandiamine derivative (1) may be contained in the charge generation layer for the purpose of further improving the sensitivity of the photoreceptor.
The charge generating agent, electron transporting agent and binder resin used in the electrophotographic photoreceptor of the present invention are as follows. [Charge Generating Agent] As the charge generating agent, for example, a general formula (CG
1):

[0029]

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Metal-free phthalocyanine represented by the general formula
(CG2):

[0031]

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A titanyl phthalocyanine represented by the general formula (CG3):

[0033]

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(In the formula, R ^20A and R ^20B are the same or different and each represents a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, alkanoyl group or aralkyl group having 18 or less carbon atoms). Perylene pigments of the general formula (CG4):

[0035]

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(In the formula, Q is a group (Q-1) to (Q-8):

[0037]

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[0038]

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Wherein Cp ¹ and Cp ² are the same or different, and the groups (Cp-1) to (Cp-11):

[0040]

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[0041]

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Is shown. ) And bisazo pigments represented by. The symbols indicating the substituents and the number of the substituents in the groups (Q-1) to (Q-8) are as follows. R ²¹ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group. ω is 0 or 1.

R ^22A , R ^22B , R ^22C , R ^22D and R
^22E is the same or different and is a hydrogen atom, a halogen atom,
An alkyl group, an alkoxy group, an aryl group or an aralkyl group is shown. R ²³ represents a hydrogen atom, a chlorine atom or an ethyl group which may have a hydroxyl group. Substituents in the above groups (Cp-1) to (Cp-9) are as follows.

R ³⁰ represents an acyl group having an amino group. R ³¹ represents an atomic group necessary for being condensed with a benzene ring to form an aromatic ring, a polycyclic hydrocarbon or a heterocycle. R ³² represents an oxygen atom, a sulfur atom or an imino group. R ³³ represents an alkylene group or an arylene group.

R ³⁴ represents an alkyl group, an aryl group, an aralkyl group or a heterocyclic group. R ³⁵ is an alkylene group, an arylene group, or the above general formulas (Cp-7) to (Cp-10).
It represents an atomic group necessary for forming a heterocycle with the two nitrogen atoms therein. R ^36a represents an acyl group having a hydrogen atom, an alkyl group, an aryl group, an amino group, a cyano group, a carboxyl group, an alkoxycarbonyl group or an amino group.

R ^36b represents an alkyl group or an aryl group. The substituents exemplified as R ^{30 to} R ³⁵ , R ^36a and R ^36b are further a halogen atom, a hydroxyl group, a nitro group, an amino group, a cyano group, an alkyl group, an alkenyl group, an alkoxy group, an aryl group, a carbonyl group and a carboxyl group. It may have a substituent such as a group.

In the charge generation agent exemplified above, the alkyl, alkoxy group, aryl group and aralkyl group include the same groups as described above. 18 carbon atoms
The following substituted or unsubstituted alkyl group is a group containing octyl, nonyl, decyl, dodecyl, tridecyl, pentadecyl, octadecyl, etc. in addition to the above-mentioned alkyl group having 1 to 6 carbon atoms. Examples of the cycloalkyl group include, for example, cyclopropyl, cyclobutyl, cyclopentyl,
Examples thereof include groups having 3 to 8 carbon atoms such as cyclohexyl, cycloheptyl, and cyclooctyl. Examples of the alkanoyl group include groups such as formyl, acetyl, propionyl, butyryl, pentanoyl, and hexanoyl.
Examples of the alkenyl group include groups having 2 to 6 carbon atoms such as vinyl, allyl, 2-butenyl, 3-butenyl, 1-methylallyl, 2-pentenyl and 2-hexenyl groups, and further have an aryl group. May be. Examples of the alkylene group include groups such as ethylene, trimethylene, propylene and tetramethylene. Examples of the arylene group include groups such as phenylene, naphthylene and phenanthrylene.

Examples of the acyl group having an amino group include groups such as carbamoyl, glycyl, carbazoyl, sulfamoyl, oxamoyl, succinamoyl, allofanoyl, hydantoyl, anthraniloyl and phthalamoyl. Examples of the heterocyclic group include thienyl, furyl, pyranyl, pyrrolyl, pyrrolidinyl, imidazolyl, 2H-imidazolyl, pyrazolyl, triazolyl, tetrazolyl, thiazolyl, isothiazolyl,
Examples include groups such as oxazolyl, isoxazolyl, pyridyl, piperidinyl, piperidino, 3-morpholinyl, and morpholino. These groups may be fused with an aromatic ring.

Examples of the aromatic ring formed by the condensation of R ³¹ and the benzene ring include naphthalene, anthracene, phenanthrene, pyrene, chrysene and naphthacene. Examples of polycyclic hydrocarbons include carbazole, benzocarbazole, dibenzofuran and the like. Examples of the heterocycle include benzofuran, benzothiophene, indole, indoline, carbazole, chromene, benzopyran, xanthene, quinoline, phenanthridine, acridine, benzimidazole, indazole, quinoxaline, quinazoline, cinnoline, phthalazine, thianthrene, phenoxathiin, Examples include phenoxazine, phenothiazine and phenazine.

Examples of the aromatic heterocyclic group formed with two nitrogen atoms in R ³⁵ include benzimidazole, benzo [f] benzimidazole, dibenzo [e, g] benzimidazole, benzopyrimidine and the like. The group is raised. These groups may have the same substituents as described above. In addition to the above charge generating agent, as represented by the following general formulas (CG5) to (CG12), dithioketopyrrolopyrrole pigment (CG5) and metal-free naphthalocyanine pigment (C
G6), metal naphthalocyanine pigment (CG7), squaraine pigment (CG8), trisazo pigment (CG9), indigo pigment (CG1)
0), azurenium pigment (CG11), cyanine pigment (CG12) and the like.

[0051]

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[0052]

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[0053]

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[0054]

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Substituents in the above general formulas (CG5) to (CG12) are as follows. R ^25A , R ^25B , R
^25C , R ^25D , R ^25E , R ^25F , R ^25G , R ^25H , R
^25J , R ^25K , R ^25L , R ^25M , R ^25N and R ^25P are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ^26A and R ^26B are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group.

R ^27A , R ^27B , R ^27C , R ^27D , R ^27E
And R ^27F are the same or different and each represents a hydrogen atom, an alkyl group or an aryl group. M represents a titanium atom or a vanadium atom, and Z represents an oxygen atom or a sulfur atom. Cp ³ , Cp ⁴ and Cp ⁵ are the same or different and represent the groups represented by the above groups (Cp-1) to (Cp-11).

In the present invention, in addition to the charge generators exemplified above, for example, selenium, selenium-tellurium, amorphous silicon, pyrylium salts, ansanthuron pigments, triphenylmethane pigments, threne pigments, toluidine pigments, Conventionally known charge generating agents such as pyrazoline pigments and quinacridone pigments can be used. The charge generating agents exemplified above can be used alone or in combination of two or more so as to have an absorption wavelength in a desired region.

Among the charge generating agents exemplified above, particularly preferable charge generating agents include phthalocyanine pigments such as X-type metal-free phthalocyanine and oxotitanyl phthalocyanine,
Examples include perylene pigments and bisazo pigments. The phthalocyanine pigment is suitably used for a digital optical system image forming apparatus having sensitivity in a wavelength region of 700 nm or more. On the other hand, the perylene-based pigment and the bisazo-based pigment are suitably used for an analog optical image forming apparatus having sensitivity in the visible region. [Electron Transfer Agent] Examples of the electron transfer agent include compounds represented by the following general formulas (ET1) to (ET14).

[0059]

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[0060]

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[0061]

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[0062]

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The symbols representing the substituents and the number of the substituents in the above general formulas (ET1) to (ET14) are as follows. R ^70A , R ^70B , R ^70C and R ^70D are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a cycloalkyl group or an amino group. However, two of R ^{70A to} R ^70D are the same group. Of the groups exemplified above, the substituent other than the hydrogen atom may further have a substituent.

R ^71A , R ^71B and R ^71C are the same or different and each represents a halogen atom, an alkyl group, an alkoxy group,
An aryl group, an aryloxy group or an aralkyl group is shown. Of these groups, the substituents other than the halogen atom may further have a substituent. γ, δ and ε are the same or different and each is an integer of 0 to 5. R ⁷² , R ^73A , R
^73B and R ⁷⁴ are the same or different and each represents an alkyl group. Γ is an integer of 1 to 4, and α is an integer of 0 to 4.

Δ is 1 or 2. R ^75A and R
^75B is the same or different and is a hydrogen atom, a halogen atom,
It represents an alkyl group, an alkoxy group, an aryl group, an aralkyloxycarbonyl group, a hydroxyl group, a nitro group or a cyano group. Q is an oxygen atom, group: = N-CN or group: = C
(CN) ₂ is shown.

R ⁷⁶ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent. R ^77A and R ^77B are the same or different and each represent a hydrogen atom, a halogen atom, a cyano group, a nitro group,
An alkyl group, an aryl group, an alkoxycarbonyl group or an N-alkylcarbamoyl group is shown. Among the groups exemplified above, the alkyl group, aryl group, alkoxycarbonyl group and N-alkylcarbamoyl group may further have a substituent. Θ and Λ are the same or different and are 1 to 3
Is an integer.

R ^78A and R ^78B are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group which may have a substituent or an alkoxycarbonyl group which may have a substituent. . Θ and Λ are the same or different and are integers of 1 to 3. R ^79A and R
^79B are the same or different and each represents an aryl group which may have a substituent or a heterocyclic group which may have a substituent.

R ⁸⁰ represents an amino group, a dialkylamino group, an alkyl group, an alkoxy group or a phenyl group. R ⁸¹
Represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group. These groups may further have a substituent. In the electron transfer agent, when the symbols α, γ, δ, ε, ω, Γ, Θ or Λ are 2 or more,
Alternatively, when the code Δ is 2, the substituents associated with the code may be different from each other.

In the electron transfer agent exemplified above, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group,
As the aryl group, aralkyl group and heterocyclic group,
The same groups as described above can be mentioned. Further, examples of the substituent which may be substituted on the above group include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group and the like.

In addition to the electron transfer agents exemplified above, for example, benzoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromoanil, 2,4,7-trinitro-9- Dicyanomethylene fluorenone, 2,
Electrons such as 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride A conventionally known electron transporting substance such as an attracting material or a polymer of these electron attracting materials can be used. [Binder Resin] As the binder resin for dispersing the components such as the hole transport agent, the charge generating agent and the electron transport agent, various resins conventionally used in the photosensitive layer can be used. Examples of such resins include styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic copolymers, styrene-acrylic acid copolymers, polyethylene,
Ethylene-vinyl acetate copolymer, chlorinated polyethylene,
Polyvinyl chloride, polypropylene, ionomer, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate,
Thermoplastic resin such as polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, polyester resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin and other crosslinkable thermosetting resin Resins, and photocurable resins such as epoxy acrylate and urethane-acrylate. These may be used alone or
A mixture of more than one species is used. Among the binder resins exemplified above, styrene-based polymers, acrylic-based polymers, styrene-
Acrylic copolymer, polyester, alkyd resin, polycarbonate, polyarylate and the like are more preferably used.

In the electrophotographic photosensitive member of the present invention, a hole-transporting agent represented by the following general formulas (HT1) to (HT9) is added together with the dibenzofurandiamine derivative represented by the general formula (1). You may use together.

[0072]

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[0073]

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[0074]

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[0075]

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Substituents in the above general formulas (HT1) to (HT9) are as follows. R ^45A , R ^45B , R
^47A , R ^47B , R ^47C , R ^48A , R ^48B , R ^48C , R
^48D , R ^49A , R ^49B , R ^49C , R ^49D , R ^49E , R
^51A , R ^51B , R ^51C , R ^52A , R ^52B , R ^52C , R
^53A , R ^53B , R ^53C , R ^53D , R ^55A , R ^55B , R
^55C and R ^55D are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent.

R ^46A , R ^46B , R ^46C and R ^46D are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent. R ⁵⁰ represents a hydrogen atom or an alkyl group. R ^54A ,
^R54B , ^R54C , ^R54D , ^R54E and ^R54F are the same or different and each represents an alkyl group, an alkoxy group or an aryl group. These groups may have a substituent. θ is 1 to
It is an integer of 10 and λ, μ, ξ, π, σ and φ are the same or different and are 1 or 2.

The group A has the following formula:

[0079]

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The group (A1), (A2) or (A3) represented by In the above hole transport material, reference numerals λ, μ, ξ,
When π, σ or φ is 2, the substituents associated with the sign may be different from each other. In the hole transport material exemplified above, examples of the halogen atom, the alkyl group, the alkoxy group and the aryl group include the same groups as described above. The substituent that may be substituted on the above groups is the same as described above.

In addition to the hole transporting agents exemplified above, for example, 2,5-di (4-methylaminophenyl) -1,3,3
Oxadiazole compounds such as 4-oxadiazole,
Styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, and hydrazone compounds. , Triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, etc., nitrogen-containing cyclic compounds, condensed polycycles Conventionally known hole transporting substances such as formula compounds can be used.

Next, a method for manufacturing the electrophotographic photosensitive member of the present invention will be described. In order to obtain a single-layer type electrophotographic photoreceptor, the dibenzofurandiamine derivative (1) of the present invention is dissolved or dispersed in a suitable solvent together with a charge generating agent, a binder resin, etc., and the coating solution thus obtained, It may be applied on the conductive substrate by a means such as application and dried. Also,
The coating solution may contain a hole-transporting agent other than the above-mentioned dibenzofurandiamine derivative (1), the electron-transporting agent exemplified above, and the like.

In the single-layer type photoreceptor, the charge generating agent is
0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, may be added to 100 parts by weight of the binder resin,
The hole transport material is used in an amount of 5 to 50 with respect to 100 parts by weight of the binder resin.
It may be added in an amount of 0 parts by weight, preferably 25 to 200 parts by weight. Further, when the electron transfer agent is blended, the blending amount is appropriately 5 to 100 parts by weight, preferably 10 to 80 parts by weight, relative to 100 parts by weight of the binder resin. The thickness of the single-layer type photosensitive layer is 5 to 100 μm, preferably 10 to 50 μm.

In order to obtain a laminated type electrophotographic photosensitive member, first, a charge generating layer containing a charge generating agent is formed on a conductive substrate by means such as vapor deposition or coating, and then, on this charge generating layer, Dibenzofurandiamine derivative of the present invention
A coating liquid containing (1) and a binder resin may be applied by a means such as coating and dried to form the charge transport layer.
In the multi-layer type photoreceptor, the charge generating agent and the binder resin constituting the charge generating layer can be used in various ratios, but the charge generating agent is added in an amount of 5 to 100 parts by weight of the binder resin.
It is suitable to blend in a proportion of 1000 parts by weight, preferably 30 to 500 parts by weight. When the charge transfer layer contains a hole transfer agent, the hole transfer agent is contained in an amount of 10 to 500 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the binder resin.
It is suitable to blend in parts by weight.

The electron-transporting agent and the binder resin constituting the charge-transporting layer can be used in various proportions within the range that does not hinder the transport of charge and the range that does not crystallize, but in the charge-generating layer by light irradiation. In order to easily transport the generated charges, the charge transfer agent containing the dibenzofurandiamine derivative (1) of the present invention is added in an amount of 10 to 5 with respect to 100 parts by weight of the binder resin.
It is suitable to blend in an amount of 00 parts by weight, preferably 25 to 100 resin. When the electron transport agent is contained in the charge transport layer, it is appropriate to add the electron transport agent in an amount of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the laminated photosensitive layer is about 0.01 to 5 μm, preferably 0.1 to 5 μm for the charge generation layer.
The thickness is about 3 μm, and the thickness of the charge transport layer is about 2 to 100 μm, preferably about 5 to 50 μm.

In the case of a single-layer type photosensitive member, between the conductive substrate and the photosensitive layer, and in the case of the laminated type photosensitive member, between the conductive substrate and the charge generating layer, the conductive substrate and the charge generating layer. A barrier layer may be formed between the transport layer and the charge generation layer and the charge transport layer as long as the characteristics of the photoreceptor are not impaired.
Further, a protective layer may be formed on the surface of the photoconductor.

Various additives known per se, such as an antioxidant, a radical scavenger, and a singlet quencher, are added to each of the single-layer type and laminated type photosensitive layers as long as they do not adversely affect the electrophotographic characteristics. A deterioration inhibitor such as an ultraviolet absorber, a softening agent, a plasticizer, a surface modifier, a bulking agent, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor and the like can be added. Also, in order to improve the sensitivity of the photosensitive layer,
For example, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

As the conductive substrate used in the photoreceptor of the present invention, various conductive materials can be used. For example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium. , Cadmium, titanium,
Examples include simple metals such as nickel, palladium, indium, stainless steel, and brass, plastic materials obtained by vapor deposition or laminating of the above metals, and glass coated with aluminum iodide, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. In addition, it is preferable that the conductive substrate has sufficient mechanical strength when used. The photosensitive layer according to the invention is manufactured by applying a coating solution obtained by dissolving or dispersing a resin composition containing the above-described components in a solvent onto a conductive substrate and drying the coating solution.

That is, the above-mentioned charge generating agent, charge transporting agent, binder resin and the like are used together with an appropriate solvent by a known method such as a roll mill, a ball mill, an attritor, a paint shaker or an ultrasonic disperser. The coating liquid may be prepared by dispersing and mixing, and the coating liquid may be coated and dried by a known means. As a solvent for preparing the coating liquid, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol, n-hexane, octane, aliphatic hydrocarbons such as cyclohexane, benzene, Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, cyclohexanone, etc. Ketones, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like. These solvents can be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge transporting material and the charge generating material and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent and the like may be used.

[0092]

Examples Synthesis of dibenzofurandiamine derivative Synthesis example 1 N, N, N ', N'-tetra (m-tolyl) -3,7-
Synthesis of dibenzofurandiamine (1-1) 3,7-dibenzofurandiamine (3) as starting material
9.91 g and 33.6 g of 3-iodotoluene were used. This starting material was added to 300 mL of nitrobenzene together with 27.6 g of potassium carbonate and 2 g of copper powder, and the mixture was refluxed for 24 hours and reacted under a nitrogen atmosphere with vigorous stirring. Water generated during the reaction is azeotropically removed with nitrobenzene, the reaction solution is cooled, and then the inorganic substances are filtered off,
Nitrobenzene was distilled off by steam distillation. The residue thus obtained was dissolved in cyclohexane, separated and purified by silica gel chromatography, and then cyclohexane was distilled off to obtain a white precipitate. The white precipitate was recrystallized from n-hexane to obtain 9.77 g (yield 35%) of the compound represented by the formula (1-1).

The elemental analysis results of the compound (1-1) are as follows. Calculated value (%) C: 85.99 H: 6.13 N: 5.02 Measured value (%) C: 85.89 H: 6.09 N: 5.01 Synthesis example 2 N, N′-di ( m-tolyl) -N, N'-di (4'-ethyl-4-biphenylyl) -3,7-dibenzofurandiamine (1-3) synthesis 3,7-dibenzofurandiamine (3) and acetyl chloride : 2 (molar ratio) to obtain a diacetylated product of 3,7-dibenzofurandiamine, and then the diacetylated product and 3-iodotoluene are reacted at a ratio of 1: 2 (molar ratio). Deacetylated. Then, the obtained N, N′-di (m-tolyl) -3,7-dibenzofurandiamine and 4-ethyl-4′-iodobiphenyl were reacted at a ratio of 1: 2 (molar ratio) to obtain A compound represented by the formula (1-3) was obtained.

The elemental analysis results of the compound (1-3) are as follows. Calculated value (%) C: 87.76 H: 6.28 N: 3.79 Measured value (%) C: 87.73 H: 6.24 N: 3.77 Synthetic Example 3 N, N, N ′, Synthesis of N'-tetra (m-tolyl) -1-methyl-3,7-dibenzofurandiamine (1-4) In place of 3,7-dibenzofurandiamine (3), 1-methyl-3,7-dibenzofurandiamine In the same manner as in Synthesis Example 1 except that was used, a compound represented by the above formula (1-4) was obtained.

The elemental analysis results of the compound (1-4) are as follows. Calculated value (%) C: 85.82 H: 6.50 N: 4.89 Measured value (%) C: 85.80 H: 6.50 N: 4.86 Synthesis Example 4 N, N'-di ( m-tolyl) -N, N'-di (2,4-
Synthesis of xylyl) -3,7-dibenzofurandiamine (1-7) In the same manner as in Synthesis Example 2 except that 4-iodo-1,3-xylene was used instead of 4-ethyl-4′-iodobiphenyl. A compound represented by the above formula (1-7) was obtained.

The elemental analysis results of the compound (1-7) are as follows. Calculated value (%) C: 85.67 H: 6.85 N: 4.76 Measured value (%) C: 85.65 H: 6.83 N: 4.73 Production of electrophotographic photosensitive member And in the comparative example, the charge generating agent,
A metal-free phthalocyanine represented by the formula (CG1),
The titanyl phthalocyanine represented by the formula (CG2), the formula (C
G3-1):

[0097]

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Perylene pigments represented by the formulas (CG4-1), (C
G4-2) and (CG4-3):

[0099]

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Any of the bisazo pigments represented by: was used. As the hole-transporting agent, the dibenzofurandiamine derivative of the present invention obtained in Synthesis Examples 1 to 4 and a compound represented by the formula (2-1):

[0101]

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A phenylenediamine derivative represented by: was used. The electron transfer agent has the formula (ET-1):

[0103]

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The diphenoquinone derivative represented by: was used. Further, the following tests were conducted on the electrophotographic photoreceptors obtained in Examples and Comparative Examples to evaluate the sensitivity and durability of the photoreceptors. (Initial electrical characteristic test) An applied voltage was applied to the surface of the electrophotographic photosensitive member obtained in each of the examples and comparative examples by using a drum sensitivity tester manufactured by GENTEC, and the surface was ± 700 ± 20V. Surface potential Vo (V)
Was measured. Then, this photosensitive member is irradiated with light for 1.5 seconds to be exposed to light, and the time required for the surface potential to be reduced to _1/2 is measured to obtain a half-exposure amount E _1/2 (μJ / cm ² ). I asked. Further, the surface potential (residual potential) Vr (V) of the photoconductor after 0.5 seconds from the start of exposure was measured. The smaller the half-exposure amount E _1/2 and the residual potential Vr, the better the sensitivity of the electrophotographic photosensitive member.

The conditions of light irradiation differ depending on the electrophotographic photosensitive member for digital light source and the electrophotographic photosensitive member for analog light source. In the case of a digital light source, a monochromatic light (halogen lamp, light intensity: 8 μJ / cm ² ) having a wavelength of 780 nm (reverse value width 20 nm) was irradiated using a bandpass filter. On the other hand, in the case of an analog light source, white light from a halogen lamp (light intensity: 8 lux) was applied. In addition, the magnitude of the applied voltage is + for the single-layer type electrophotographic photoconductor.
700 ± 20V, -700 ± for laminated electrophotographic photoreceptor
It is 20V. (Repeat Characteristic Test) After the electrophotographic photoreceptors obtained in the respective examples and comparative examples were used to form images 20,000 times,
By the same method as the initial electrical characteristic test, the surface potential Vo
And the residual potential Vr was measured. Next, the differences ΔVo (V) and ΔVr (V) from the respective initial values were obtained, and the electrical characteristics after repeated exposure were evaluated. In addition, ΔVo
The smaller the value of ΔVr and the smaller the value of ΔVr, the smaller the deterioration even after repeated exposure and the more stable the electrical characteristics.

The apparatus used for image formation is a laser beam printer (model TC-650 manufactured by Mita Kogyo Co., Ltd.) in the case of a photoconductor for a digital light source. On the other hand, in the case of a photoreceptor for an analog light source, an electrostatic copying machine (model number DC2556 manufactured by Mita Industry Co., Ltd.) was used. (Measurement of Abrasion Amount) Using the electrophotographic photoreceptors obtained in the respective examples and comparative examples, after image formation was carried out 20,000 times by the same method as the above-mentioned repeated characteristic test, the abrasion amount (μ
m) was measured. The smaller the amount of abrasion, the better the durability of the photoconductor. Examples 1 to 8 and Comparative Examples 1 and 2 (single-layer type electrophotographic photoreceptor for digital light source) 5 parts by weight of a charge generating agent, 100 parts by weight of a hole transferring material and 100 parts by weight of a binder resin (polycarbonate) were used as a solvent. By mixing and dispersing with 800 parts by weight of (tetrahydrofuran) in a ball mill for 50 hours, a coating solution for a single-layer type photosensitive layer was prepared. Next, this coating solution is applied onto a conductive base material (aluminum tube) by a dip coating method, and the temperature is 110 ° C.
Was dried with hot air for 30 minutes to prepare a single-layer type electrophotographic photosensitive member having a photosensitive layer having a film thickness of 25 μm.

Table 1 shows the types of the charge generating agent and the hole transferring material used in the above Examples and Comparative Examples, and the results of the electrical characteristic test. In the table below, the types of charge generating agents and hole transporting agents are indicated by chemical formula numbers.

[0108]

[Table 1]

Examples 9 to 20 and Comparative Examples 3 to 6 (single-layer type electrophotographic photoconductor for analog light source) The same procedure as in Examples 1 to 8 or Comparative Examples 1 and 2 except that the charge generating agent is different. A layer type electrophotographic photoreceptor was manufactured.
Table 2 shows the types of the charge generating agent and the hole transferring material used and the results of various tests.

[0110]

[Table 2]

Examples 21 to 28 (single-layer type electrophotographic photoreceptor for digital light source) In addition to 5 parts by weight of the charge generating agent, 100 parts by weight of the hole transferring material and 100 parts by weight of the binder resin (polycarbonate), an electron was further added. Example 1 except that 30 parts by weight of the transport agent was blended.
A single-layer type electrophotographic photosensitive member was manufactured in the same manner as described in Nos. 8 to 8. Table 3 shows the types of the charge generating agent, hole transporting agent, and electron transporting agent used and the results of various tests. In the table below, electron transfer agents are indicated by their chemical formula numbers.

[0112]

[Table 3]

Examples 29 to 40 (single-layer electrophotographic photoreceptor for analog light source) Single-layer electrophotographic photoreceptors were manufactured in the same manner as in Examples 21 to 24 except that the charge generating agent was different. Table 4 shows the types of the charge generating agent, hole transporting agent and electron transporting agent used and the results of various tests.

[0114]

[Table 4]

Examples 41 to 48, Comparative Examples 7 to 8 (multilayer electrophotographic photoreceptor for digital light source) 2.5 parts by weight of a charge generating agent and 1 part by weight of a binder resin (polyvinyl butyral) were used as a solvent (tetrahydrofuran). 1
5 parts by weight were mixed and dispersed in a ball mill to prepare a coating solution for the charge generation layer. Then, this coating solution is applied on a conductive substrate (aluminum tube) by a dip coating method, dried with hot air at 110 ° C. for 30 minutes, and a film thickness of 0.
A 5 μm charge generation layer was formed.

Next, 1 part by weight of the hole transfer material and 1 part by weight of a binder resin (polycarbonate) were mixed and dispersed in a ball mill together with 10 parts by weight of a solvent (tetrahydrofuran) to prepare a coating solution for the charge transfer layer. did. Next, this coating solution was applied onto the charge generation layer by a dip coating method and dried with hot air at 110 ° C. for 30 minutes to form a charge transport layer having a film thickness of 20 μm, and a laminated electrophotographic photoreceptor was manufactured. .

Table 5 shows the types of charge generating agents and hole transferring agents used in the above Examples and Comparative Examples and the results of various tests.
Shown in

[0118]

[Table 5]

Examples 49 to 60, Comparative Examples 9 to 12 (Layered Electrophotographic Photosensitive Member for Analog Light Source) Laminated type similar to Examples 41 to 48 or Comparative Examples 7 to 8 except that the charge generating agent is different. An electrophotographic photoreceptor was manufactured. Table 6 shows the types of the charge generating agent and the hole transferring material used and the results of various tests.

[0120]

[Table 6]

As is apparent from Tables 1 to 6, Examples 1 to 6 using the dibenzofurandiamine derivative (1) of the present invention
The electrophotographic photoconductor of No. 0 has excellent sensitivity as compared with the electrophotographic photoconductor of the comparative example using the conventional phenylenediamine derivative, has little deterioration even after repeated exposure, and has stable electric characteristics. There is. Furthermore, it has excellent abrasion resistance.

Further, as is clear from Tables 3 and 4, the electrophotographic photoreceptors of Examples 21 to 40 in which the dibenzofurandiamine derivative (1) and the electron transfer agent were used in combination were more sensitive and sensitive than other examples. Excellent stability of electrical characteristics.

[0123]

The dibenzofurandiamine derivative of the present invention
(1) has a high charge transporting ability and is also excellent in stability. Therefore, the dibenzofurandiamine derivative (1) of the present invention can be suitably used as a charge transfer agent, especially a hole transfer agent in, for example, an electrophotographic photoreceptor, a solar cell, an electroluminescence device and the like.

Further, the electrophotographic photosensitive member of the present invention is superior in sensitivity characteristics to the conventional photosensitive member, and is excellent in stability after repeated exposure and is also excellent in abrasion resistance. . Furthermore, when an electron transfer agent is used in combination, more excellent sensitivity characteristics are exhibited. Therefore, the electrophotographic photosensitive member of the present invention has a unique effect that it contributes to high speed and high performance of various image forming apparatuses such as electrostatic copying machines and laser beam printers.

Claims (3)

[Claims] [Claim 1] General formula (1): (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are the same or different and each represents a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group. The alkyl group, the alkoxy group, the aryl group And the aralkyl group may have a substituent, and a, b, c and d are the same or different and are integers of 0 to 5, and e is an integer of 0 to 6.
When ~ e is 2 or more, the respective substituents may be different from each other. ) The dibenzofurandiamine derivative represented by the following formula. 2. An electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate, wherein the photosensitive layer is a compound represented by the general formula:
An electrophotographic photoreceptor containing the dibenzofurandiamine derivative represented by (1). 3. The electrophotographic photosensitive member according to claim 2, wherein the photosensitive layer is a single-layer type photosensitive layer further containing at least a charge generating agent and an electron transporting agent.