JP2007254386A - Triarylamine derivative, method for producing the same and electronic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic photoreceptor having excellent solubility and compatibility, and good sensitivity, and capable of maintaining the sensitivity for a long time. <P>SOLUTION: The triarylamine derivative is represented by general formula (I) (wherein, R<SP>1</SP>to R<SP>8</SP>are each hydrogen, a halogen, an alkyl group, an alkoxy group, an aryl group or an aryloxy group; Ar is a heterocyclic group, a condensed polycyclic hydrocarbon group, a ring-aggregated hydrocarbon group, a condensed heterocyclic group or a ring-aggregated heterocyclic group). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a triarylamine derivative, a method for producing the same, and an electrophotographic photosensitive member.

  Conventionally, as an electrophotographic photoreceptor for wet development used in an image forming apparatus or the like, an organic photoreceptor made of an organic photoreceptor material such as a charge transport agent, a charge generator, and a binder resin (binder resin) has been used. . Such an organic photoreceptor is advantageous in that it is easy to manufacture and has a wide degree of freedom in structural design because it has various options for the photoreceptor material as compared with an inorganic photoreceptor.

  Among these organophotoreceptor materials, the charge transport material having a predetermined charge mobility is represented by the following formula:

(In the formula, Rr ^{1 to} Rr ² are each an alkyl group, an alkoxy group, etc.)
A symmetric stilbene compound represented by the formula is known (for example, see Patent Documents 1 and 2).
JP-A-5-113678 (Claims) Japanese Patent Laid-Open No. 4-253055 (Claims)

  However, since the compounds described in Patent Documents 1 and 2 have insufficient charge mobility, when used as a charge transport material in an electrophotographic photosensitive member, the sensitivity is insufficient and the compound is dissolved in a solvent. There is a problem that the compatibility and the compatibility with the binder resin are poor.

  The present invention has been made in view of the above problems, and is a triaryl that is excellent in solubility in a solvent and compatibility with a binder resin, has good sensitivity, and can maintain predetermined sensitivity for a long time. An object is to provide an amine derivative, a method for producing the same, and an electrophotographic photoreceptor.

  Surprisingly, the present inventors use a triarylamine derivative that is asymmetric with a conjugated double bond as the center as a charge transporting material, thereby being excellent in solubility in a solvent and compatibility with a binder resin. The present invention has been completed by discovering that a predetermined sensitivity can be maintained over a long period of time and a predetermined sensitivity can be maintained.

  That is, the triarylamine derivative of the present invention has the general formula (I)

(In the formula, R ^{1 to} R ⁸ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group or a substituted group. Aryloxy group which may be substituted, Ar is a heterocyclic group which may be substituted, condensed polycyclic hydrocarbon group which may be substituted, ring assembly hydrocarbon group which may be substituted, substituted A condensed heterocyclic group which may be substituted, a ring assembly heterocyclic group which may be substituted)
It is represented by.

  In addition, the production method of the triarylamine derivative of the present invention has the following reaction formula:

(In the formula, X is a halogen atom, R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, or a substituted one. An aryl group which may be substituted or aryloxy which may be substituted, Ar is a heterocyclic group which may be substituted, a condensed polycyclic hydrocarbon group which may be substituted, or a ring assembly carbon which may be substituted A hydrogen group, an optionally substituted condensed heterocyclic group, and an optionally substituted ring assembly heterocyclic group)
Wherein the amine derivative (8) is reacted with the halogenated aryl compound (5).

  Further, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member provided with a photosensitive layer containing at least a binder resin and a charge transporting agent on a conductive substrate, wherein the charge transporting agent is the above-described general one. It contains a triarylamine derivative represented by the formula (I).

  According to the triarylamine derivative of the present invention and the method for producing the same, the photosensitive layer has an asymmetric arylamino group with respect to a conjugated bond in the molecule as represented by the general formula (1). The solubility and the compatibility with the binder resin can be made excellent, and the durability and solvent resistance can be improved easily and reliably.

  Further, according to the electrophotographic photoreceptor using such a triarylamine derivative, crystallization of the charge transport material in the photoreceptor can be effectively prevented. In addition, the charge mobility can be increased, the sensitivity can be maintained, and the predetermined sensitivity can be maintained for a long time. As a result, it is possible to realize high speed and high performance of various image forming apparatuses such as copying machines and printers.

  The triarylamine derivative of the present invention is represented by the general formula (I) described above.

In the general formula (I), examples of the halogen atom in R ^{1 to} R ⁸ include fluorine, chlorine, bromine and iodine atoms. Examples of the alkyl group include those having 1 to 6, preferably 1 to 4 carbon atoms. Specific examples include methyl, ethyl, propyl, t-butyl, n-butyl, pentyl, heptyl and the like. The alkoxy group suitably has the same number of carbon atoms as the alkyl group, and specific examples include methoxy, ethoxy, propoxy, butoxy and the like. Examples of the aryl group include those having 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms. For example, a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, and the like can be given. Of these, a phenyl group is preferred. Examples of the aryloxy group include those having 6 to 14 carbon atoms, preferably 6 to 10 carbon atoms. For example, a phenoxy group, a naphthoxy group, etc. are mentioned.

The alkyl group in R ¹ to R ^8, an alkoxy group, an aryl group, the aryloxy group, the substituents may be substituted. Although a substituent is not specifically limited, A halogen atom, an alkyl group, an alkylene group, an alkoxy group etc. are mentioned. Examples of the alkylene group include ethylene, propylene, butylene and the like, and other than the above, the same as those described above. Moreover, although one substituent may be sufficient, 2 or more, for example, 2-5, is suitable.

In particular, R ^{1 to} R ⁸ are preferably a hydrogen atom, a halogen atom, a lower alkyl having 1 to 4 carbon atoms, or a lower alkoxy having 1 to 4 carbon atoms.

In the phenyl group to which the nitrogen atom is bonded, at least one substituent is preferably substituted in the ortho position with respect to the nitrogen atom. For example, it is preferable that any one of R ^{1 to} R ³ , any one of R ^{4 to} R ^6, any one of R ⁷ or R ⁸ is substituted in the ortho position with respect to the nitrogen atom.

  Examples of the heterocyclic group in Ar include saturated or unsaturated 5- to 6-membered heterocyclic rings, and examples thereof include those containing 1 to 2 nitrogen atoms, sulfur atoms or oxygen atoms as heteroatoms. Specific examples include divalent groups such as furan, thiophene, pyrrole, oxazole, thiazole, imidazole, pyrazole, pyran, pyridine, pyrimidine, pyrroline, pyrazoline, piperidine and the like.

  The condensed polycyclic hydrocarbon group includes those having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples include indene, naphthalene, azulene, fluorene, phenanthrene, anthracene, naphthacene, pyrene, and triphenylene.

  Examples of the ring assembly hydrocarbon group include those having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples include biphenyl, terphenyl, 2-phenylnaphthyl, 1,2'-binaphthyl and the like.

  Examples of the condensed heterocyclic group include those having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples include divalent groups such as indole, benzofuran, tyndridine, chromene, quinoline, purine, indazole, carbazole and the like.

  Examples of the ring assembly heterocyclic group include those having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Specific examples include 2,3'-bifuran and 2,2'-bipyrazin-6-yl.

  These substituents may further have a substituent. Examples of the substituent include the same substituents as exemplified above.

  Examples of the triarylamine derivative of the present invention include the compounds shown below.

  Such a triarylamine derivative can be produced, for example, by the following production method.

(In the formula, X is a halogen atom, R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, or a substituted one. An aryl group which may be substituted or aryloxy which may be substituted, Ar is a heterocyclic group which may be substituted, a condensed polycyclic hydrocarbon group which may be substituted, or a ring assembly carbon which may be substituted A hydrogen group, an optionally substituted condensed heterocyclic group, and an optionally substituted ring assembly heterocyclic group)
That is, the triarylamine derivative represented by the general formula (I) can be obtained by coupling the halogenated aryl derivative represented by the formula (8) to the amine derivative represented by the formula (8).

  When the aryl halide derivative (5) is reacted with the amine derivative (8), for example, it is suitable to add at a molar ratio of about 1 to 5: 1, preferably about 2: 1. In these reactions, it is preferable to use sodium alkoxides such as sodium sodium ethoxide and sodium butoxide, metal hydrides such as sodium hydride and potassium hydride, and the like as the base. Further, it is preferable to use a catalyst such as (2-biphenyl) dicyclohexylphosphine or tris (dibenzylideneacetone) dipalladium. Although reaction time is not specifically limited, For example, about 1 to 10 hours is suitable. The reaction temperature is preferably about 80 to 180 ° C, and more preferably about 100 to 150 ° C. As the solvent used in this reaction, those which do not affect the reaction are suitable, for example, ethers such as diethyl ether, tetrahydrofuran and dioxane; halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane; Aromatic hydrocarbons such as benzene, toluene and xylene, dimethylformamide and the like.

The halogenated aryl derivative represented by (5) and the amine derivative represented by (8) can be produced as the halogenated aryl derivative 5 and the amine derivative 8 , respectively, by the following production method. In the following reaction formula, for ease of explanation, the aryl halide derivative 5 and the amine derivative 8 have specific substituents R ^{1 to} R ⁸ and Ar, respectively, and are bonded at specific positions. A compound having a substituent corresponding to the above definition can be synthesized in the same manner.

(Wherein X ′ is a halogen atom)
For example, first, the aryl halide derivative 1 is reacted with triethyl phosphite 2 in a suitable solvent. In this case, the halogenated benzene derivative 1 and triethyl phosphite 2 are preferably reacted at a molar ratio of about 1: 1 to 4, and more preferably about 1: 1 to 2. The reaction temperature is usually about 80 to 180 ° C., and the reaction time is suitably about 1 to 10 hours. Examples of the solvent used for the reaction include the same solvents as described above.

  Subsequently, the halogenated benzaldehyde 4 is reacted with the obtained phosphoric ester derivative 3 by a wittig reaction. In this case, the phosphate ester derivative 3 and the halogenated benzaldehyde 4 are preferably reacted at a molar ratio of about 1: 1 to 3, and more preferably about 1: 1 to 2. The reaction temperature is usually about −30 to 20 ° C., and the reaction time is suitably about 5 minutes to 4 hours. As a reagent used for the wittig reaction, the above-mentioned bases can be used. Thereby, the halogenated aryl derivative 5 can be obtained.

  The diarylamino derivative 8 can be obtained by coupling the halogenated benzene compound 7 to the arylamino derivative 6. In this case, it is suitable to react the arylamino derivative 6 and the halogenated benzene compound 7 in a molar ratio of, for example, about 1 to 5: 5 to 1, preferably about 1: 1. In these reactions, it is preferable to use sodium alkoxides such as sodium sodium ethoxide and sodium butoxide, metal hydrides such as sodium hydride and potassium hydride, and the like as the base. Moreover, you may use the catalyst mentioned above. Although reaction time is not specifically limited, For example, about 1 to 10 hours is suitable. The reaction temperature is preferably about 80 to 180 ° C, and more preferably about 100 to 150 ° C. Moreover, as a solvent used in this reaction, those which do not affect the reaction are suitable, and the same solvents as mentioned above can be mentioned.

  The electrophotographic photoreceptor of the present invention is generally constituted by forming a photoreceptor layer on a conductive substrate. The conductive substrate may be any material as long as the substrate itself has conductivity or the surface of the substrate has conductivity. For example, a metal such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass, or a plastic material on which these metals are deposited or laminated, Examples thereof include a plastic material in which conductive fine particles such as carbon black are dispersed, glass coated with aluminum iodide, tin oxide, indium oxide and the like. The shape of the conductive substrate may be any of a sheet shape, a drum shape, and the like according to the structure of the image forming apparatus to be used, but preferably has a sufficient mechanical strength in use.

  The photoreceptor layer may be a single layer type or a laminated type in which functions are separated by two or more layers. The thickness of the single-layer type photoreceptor layer is usually a value in the range of 5 to 100 μm, preferably a value in the range of 10 to 50 μm. In the multilayer type photoreceptor layer, for example, the charge generation layer is about 0.01 to 5 μm, preferably about 0.1 to 3 μm, and the charge transport layer is about 2 to 100 μm, preferably about 5 to 50 μm.

  In the electrophotographic photosensitive member, a barrier layer may be formed between the conductive substrate and the photosensitive layer as long as the characteristics of the photosensitive member are not impaired, and a protective layer is formed on the surface of the photosensitive layer. It may be.

1. Single layer type photoreceptor The photosensitive layer comprises at least a triarylamine derivative of the general formula (I) as a charge transport agent (for example, a hole transport agent), a binder resin, and optionally a charge generator and / or other It can be formed by dissolving or dispersing the charge transport agent in an appropriate solvent, coating the obtained coating solution on a conductive substrate, and drying. The single-layer type photoreceptor can be applied to both positive and negative charge types with a single configuration, has a simple layer configuration, and is excellent in productivity.

(1) Hole transport agent The electrophotographic photoreceptor of the present invention contains a triarylamine derivative of the general formula (I) as a hole transport agent. This compound is as described above.

  In addition, a conventionally known hole transport agent may be used in combination. For example, N, N, N ′, N′-tetraphenylbenzidine derivative, N, N, N ′, N′-tetraphenylphenylenediamine derivative, N, N, N ′, N′-tetraphenylnaphthylenediamine derivative, N, N, N ′, N′-tetraphenylphenanthrylenediamine derivatives, oxadiazole compounds such as 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, 9- (4-diethylaminostyryl) styryl compounds such as anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, indoles Compounds, oxazole compounds, isoxazole compounds, thiazole compounds Things, thiadiazole compounds, imidazole compounds, pyrazole compounds, and nitrogen-containing cyclic compounds such as triazole compounds, and condensed polycyclic compounds. Specifically, HTM-1 to HTM-13 described in JP-A-2006-8670 and JP-A-2005-306744 can be used.

  The hole transport agent is preferably contained in an amount of 10 to 80 parts by weight with respect to 100 parts by weight of the binder resin from the viewpoint of improving sensitivity and preventing crystallization to obtain appropriate film forming characteristics. .

(2) Electron transport agent Any known electron transport agent may be used as the electron transport agent. For example, naphthalenecarboxylic acid diimide derivatives, naphthoquinone derivatives, azoquinone derivatives, diphenoquinone derivatives, benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7-tetranitro-9-fluorenone derivatives , Dinitroanthracene derivatives, dinitroacridine derivatives, nitroantharaquinone derivatives, dinitroanthraquinone derivatives, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, anhydrous succinate Examples include acid, maleic anhydride, dibromomaleic anhydride and the like. These can be used alone or in combination of two or more. Specific examples include compounds represented by the following formulas (ET-1 to ET-3).

  From the viewpoint of improving sensitivity, preventing crystallization and obtaining appropriate film formability, the electron transfer agent is suitably contained in an amount of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.

  In addition, when determining the addition amount of an electron transport agent, it is preferable to consider the addition amount of a hole transport agent mentioned above. For example, from the viewpoint of improving sensitivity, the addition ratio (total ETM / total HTM) of the electron transport agent (total ETM) is set to 0.25 to 1.3 with respect to the hole transport agent (total HTM). Is preferred.

(3) Charge generator As the charge generator, metal-free phthalocyanine (τ type or x type), titanyl phthalocyanine (α type or Y type), hydroxygallium phthalocyanine (V type), and chlorogallium phthalocyanine (II type), Phthalocyanine pigments such as oxo titanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyrylium Organic photoconductors such as pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon Inorganic photoconductive agent materials such as These can be used alone or in combination of two or more. By using these compounds as charge generating agents, sensitivity characteristics, electrical characteristics, stability, and the like can be further improved when a hole transport agent and an electron transport agent are used in combination. Specific examples include phthalocyanine pigments (CGM-A to CGM-D) described in JP-A-2006-8670 and JP-A-2005-306744.

  The charge generator increases the quantum yield and also maintains the extinction coefficient for light having an absorption wavelength in the red and infrared to near-infrared regions, improving the sensitivity, electrical properties, stability, etc. of the electrophotographic photoreceptor. From the viewpoint of making it, it is appropriate to contain 0.2 to 40 parts by weight with respect to 100 parts by weight of the binder resin.

In the case of using a charge generating agent, for example, C.I. A dispersion aid such as I Pigment Orange 16 may be added. When a dispersion aid is added, the dispersibility of the charge generating agent in the solution can be improved, and the pot life of the coating solution can be extended.
In this case, it is appropriate to add 30 to 200 parts by weight with respect to 100 parts by weight of the total charge generating agent.

(4) Binder Resin The binder resin is not particularly limited as long as it is used as a binder resin in the field, and various types can be used. For example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorination Polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, polyamide resin, polyurethane resin, polycarbonate resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone Thermoplastic resins such as resin, polyvinyl butyral resin, polyether resin, polyester resin; silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resins; epoxy acrylic Over bets, urethane - interest photocurable resin and the like such as acrylate.

(5) Additives In addition to the above-mentioned components, the photosensitive layer contains various conventionally known additives such as antioxidants, radical scavengers, singlet quenchers, and the like within a range that does not adversely affect the electrophotographic characteristics. Deterioration inhibitors such as char and ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like may be added. In order to improve the sensitivity of the photoreceptor layer, for example, known sensitizers such as terphenyl, halonaphthoquinones, acenaphthylene and the like may be used in combination with the charge generator.

(6) Manufacturing method The photosensitive layer is formed by a known method such as a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser, etc. together with the above-described charge generator, charge transport agent, binder resin and the like in an appropriate solvent. It can be formed by preparing a dispersion liquid by dispersing the mixture using, and applying it to the surface of the conductive substrate by a known means and drying it.

  As the solvent for preparing the dispersion, various organic solvents can be used. For example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; benzene , Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane, dioxolane Ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylformamide, dimethyl ester Examples include til sulfoxide. These solvents can be used alone or in admixture of two or more.

  Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge transport agent or charge generator and the smoothness of the surface of the photoreceptor layer.

2. Multilayer Photoreceptor A multilayer photosensitive layer is formed by forming a charge generation layer containing a charge generation agent on a conductive substrate by means of vapor deposition or coating, and a hole transport agent on the charge generation layer. It is produced by applying a coating solution containing a binder resin and drying it to form a charge transport layer. Alternatively, a charge transport layer may be formed on the conductive substrate, and a charge generation layer may be formed thereon. However, since the charge generation layer is much thinner than the charge transport layer, it is more preferable to form the charge transport layer on the charge generation layer for protection.

  Depending on the order in which the charge generating layer and the charge transport layer are formed and the type of the charge transport agent used in the charge transport layer, the laminate type photoreceptor is selected as a positive or negative charge type. For example, when a charge generation layer is formed on a conductive substrate and a charge transport layer is formed thereon, when a hole transport agent is used as the charge transport agent in the charge transport layer, the photoreceptor is negatively charged. Become a mold. In this case, the charge generation layer may contain an electron transport agent. By adopting the laminated type, the residual potential of the photoreceptor can be greatly reduced and the sensitivity can be improved.

  As the charge generating agent, hole transporting agent, electron transporting agent, binder resin and the like, basically the same ones as those for the single layer type photoreceptor can be used. However, in the case of a multilayer photoreceptor, the amount of charge generator added is preferably 0.5 to 150 parts by weight with respect to 100 parts by weight of the binder resin constituting the charge generation layer.

  The electrophotographic photoreceptor of the present invention can be used, for example, by the image forming apparatus shown in FIG.

  The electrophotographic photosensitive member 1 is configured by forming a photosensitive layer 11 on a support base 10, and its axis 13 is connected to a driving means 14 via a gear and a pulley in one direction (arrow A). The direction of rotation is at a constant speed.

  A main charging unit 2, an exposure unit 3, a developing unit 4, and a transfer unit 5 are provided in this order along the driving direction, that is, the rotation direction, around the photoreceptor 1.

  Further, as shown in FIG. 1, a separation unit 6, a charge removal unit 7, and a cleaning unit 9 may be provided as necessary.

  Further, the image forming apparatus is provided with a fixing unit 12 for fixing the toner image to the transfer medium 8 onto which the toner image has been transferred.

  When forming an image, first, the surface of the electrophotographic photosensitive member 1 is uniformly charged by the charging means 2. Next, the surface of the electrophotographic photosensitive member 1 is exposed along the exposure axis 31 by the exposure means 3 to form an electrostatic latent image corresponding to the original image.

  Thereafter, the developing means 4 develops the toner attached to the portion corresponding to the electrostatic latent image.

  Subsequently, the toner image on the surface of the photoreceptor 1 is transferred onto the transfer medium 8 conveyed (in the direction of arrow B) by the transfer unit 5. After the transfer, the transfer medium 8 is separated from the electrophotographic photosensitive member 1 by the separating unit 6 and then toner-fixed by the fixing unit 12.

  After the transfer, the toner that cannot be transferred to the transfer medium 8 and remains on the surface of the electrophotographic photosensitive member 1 is removed by the cleaning means 9.

  Thereafter, the residual potential on the surface of the electrophotographic photosensitive member 1 is removed by the neutralizing light 71 from the neutralizing unit 7 and charged by the charging unit 2 again.

  Examples of the triarylamine derivative and the electrophotographic photoreceptor of the present invention will be described below.

[Examples 1 to 3]
(Synthesis of triarylamine derivatives)
First, the following manufacturing process

According to the above, compound 1 (120 g, 0.57 mol) and triethyl phosphite 2 (113 g, 0.68 mol) were weighed in a 1 L two-necked flask and reacted at 150 ° C. for 2 hours. After cooling, excess triethyl phosphite was distilled off under reduced pressure, and the residue was purified by crystallization with chloroform / hexane = 100 ml / 500 ml to obtain white crystals 3 (134 g, yield 75.4%).

  Next, the obtained white crystals 3 (20 g, 0.064 mol) were placed in a 500 mL two-necked flask at 0 ° C., and purged with argon. Further, 100 mL of dry THF, 28% sodium methoxide (14 0.8 g, 0.077 mol) was added and stirred for 30 minutes. Thereafter, chlorobenzaldehyde 4 (11.3 g, 0.081 mol) dissolved in 50 ml of dry THF was introduced and stirred at room temperature for 12 hours. The obtained reaction solution was poured into ion exchange water, extracted with toluene, and the organic layer was washed 5 times with ion exchange water. Subsequently, the obtained organic layer was dried over anhydrous sodium sulfate, and then the solvent was distilled off. The residue was purified with toluene / methanol = 100 ml / 200 ml to obtain white crystals 5 (15.9 g, yield 83%).

  In addition to the above reaction, in a 1 L two-necked flask, chlorobenzene 7 (45 g, 0.4 mol), 2- (dicyclohexylphosphino) biphenyl (0.35 g, 1 mmol), trisdibenzylideneacetone dipalladium ( 0.458 g, 0.5 mmol), t-BuONa (28.83 g, 0.3 mol), compound 6 (54.1 g, 0.4 mol), and 400 ml of o-xylene, and substituted with argon. The mixture was stirred at 0 ° C. for 3 hours and then cooled to room temperature. The organic layer in the reaction solution was washed with ion-exchanged water three times, anhydrous sodium sulfate and activated clay were added to the organic layer, dried and adsorbed, and xylene was distilled off under reduced pressure. The obtained residue was purified by column chromatography (developed with chloroform / hexane) to obtain white crystals (yield 73.3 g, yield 86.7%) as compound 8.

  Next, the following reaction formula

As shown in FIG. 1, a 500 mL two-necked flask was charged with compound 5 (12 g, 0.04 mol), 2- (dicyclohexylphosphino) biphenyl (0.07 g, 0.2 mmol), trisdibenzylideneacetone dipalladium ( 0.092 g, 0.1 mmol), t-BuONa (5.78 g, 0.06 mol), compound 8 (16.9 g, 0.0802 mol), 200 ml of o-xylene, and substituted with argon. The mixture was stirred at 0 ° C. for 3 hours and then cooled to room temperature. The organic layer in the reaction solution was washed with exchanged water three times, anhydrous sodium sulfate and activated clay were added to the organic layer, dried and adsorbed, and xylene was distilled off under reduced pressure. The obtained residue was purified by column chromatography (developed with chloroform / hexane) to give yellow crystals (yield 17.7 g, yield 68%) as compound HT-1.

(Preparation of electrophotographic photoreceptor)
60 parts by weight of the obtained triarylamine derivative (compound represented by HT-1 in the above formula) as a hole transporting agent and 5 X-type metal-free phthalocyanine (CGM-A) as a charge generating agent 100 parts by weight of a Z-type polycarbonate resin as a binder resin, 0.1 part by weight of KF-96-50CS (Shin-Etsu Chemical Co., Ltd.), which is a dimethyl silicone oil as a leveling agent, and tetrahydrofuran as a solvent Added to 800 parts by weight. Subsequently, it was mixed and dispersed for 50 hours using a ball mill to prepare a coating solution for the photosensitive layer. The obtained coating solution is applied on a conductive base material (aluminum tube) having a diameter of 30 mm and a length of 254 mm by dip coating, and dried with hot air at 100 ° C. for 30 minutes. An electrophotographic photosensitive member having a single-layer type photosensitive layer having a thickness of 25 μm was obtained.

(Evaluation)
The initial electric characteristics, that is, the initial surface potential (Vo) and the residual potential (Vr) of the obtained electrophotographic photosensitive member were measured.

  First, using a drum sensitivity tester (manufactured by GENTEC), the surface potential was charged to +700 V, and the initial surface potential (Vo) was measured.

Next, in the charged state, the surface of the photoreceptor is irradiated with monochromatic light (half-width: 20 nm, light intensity: 1.5 μJ / cm ² ) having a wavelength of 780 nm extracted from the light of the halogen lamp using a bandpass filter. (Irradiation time 1.5 seconds) The surface potential at the time when 0.5 seconds passed from the start of exposure was measured, and this was defined as the residual potential (Vr). The obtained results are shown in Table 1.

[Examples 4 to 6]
In Example 1, instead of the chloromethyl compound of Compound 1, the following compound 1-2

Compound HT-2 was synthesized in the same manner as in Example 1 except that was used (yield: 40.3%), and an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Examples 7 to 9]
In Example 1, instead of the chloromethyl compound of Compound 1, the following Compound 1-3, and instead of the arylamino derivative 6 of Compound 6, the following Compound 6-2

Compound HT-3 was synthesized in the same manner as in Example 1 except that was used (yield: 31.2%), and an electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1 to 9]
In Comparative Examples 1 to 9, as a hole transport material, the following formula

An electrophotographic photoreceptor was prepared and evaluated substantially in the same manner as in Example 1 except that the compound shown in 1 was used. The results are shown in Table 1.

  According to Table 1, a triarylamine derivative having an asymmetric arylamino group with respect to a conjugated bond in the molecule is used as a charge transport material, so that it has excellent solubility in a solvent and compatibility with a binder resin. It was confirmed that good sensitivity was maintained for a long time.

  The triarylamine derivative of the present invention can be used, for example, in various fields as a charge transport material requiring compatibility and sensitivity with a binder resin. In addition to maintaining the sensitivity, it can be used in various fields such as a solar cell and an electroluminescence element in addition to the electrophotographic photosensitive member of various image forming apparatuses such as a copying machine and a printer.

FIG. 2 is a schematic diagram for explaining an image forming apparatus provided with the electrophotographic photosensitive member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive member 2 Main charging means 3 Exposure means 4 Development means 5 Transfer means 6 Separation means 7 Electric discharge means 8 Transfer medium 9 Cleaning means 10 Support base 11 Photosensitive layer 12 Fixing means 13 Axis center 14 Driving means 31 Exposure shaft 71 Removal Lightning

Claims (4)

Formula (I)

(In the formula, R ^{1 to} R ⁸ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group or a substituted group. Aryloxy group which may be substituted, Ar is a heterocyclic group which may be substituted, condensed polycyclic hydrocarbon group which may be substituted, ring assembly hydrocarbon group which may be substituted, substituted A condensed heterocyclic group which may be substituted, a ring assembly heterocyclic group which may be substituted)
A triarylamine derivative represented by:   The triarylamine derivative according to claim 1, wherein in the phenyl group to which the nitrogen atom of the triarylamine derivative of the formula (I) is bonded, at least one substituent is substituted in the ortho position with respect to the nitrogen atom. The following reaction formula

(In the formula, X is a halogen atom, R ^{1 to} R ⁸ are the same or different and are a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, or a substituted one. An aryl group which may be substituted or aryloxy which may be substituted, Ar is a heterocyclic group which may be substituted, a condensed polycyclic hydrocarbon group which may be substituted, or a ring assembly carbon which may be substituted A hydrogen group, an optionally substituted condensed heterocyclic group, and an optionally substituted ring assembly heterocyclic group)
A method for producing a triarylamine derivative represented by the formula: wherein the amine derivative (8) is reacted with the halogenated aryl compound (5). An electrophotographic photosensitive member provided with a photosensitive layer containing at least a binder resin and a charge transfer agent on a conductive substrate, wherein the charge transfer agent is represented by the following general formula (I)

(In the formula, R ^{1 to} R ⁸ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, an optionally substituted aryl group or a substituted group. Aryloxy group which may be substituted, Ar is a heterocyclic group which may be substituted, condensed polycyclic hydrocarbon group which may be substituted, ring assembly hydrocarbon group which may be substituted, substituted A condensed heterocyclic group which may be substituted, a ring assembly heterocyclic group which may be substituted)
An electrophotographic photoreceptor comprising a triarylamine derivative represented by the formula:

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