JP2861116B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor using an organic photoconductive material.

[Prior art and its problems] With the development of non-impact printing technology in recent years, research and development of an electrophotographic printer using a laser as a light source have been actively conducted. In this laser beam printer, high speed, high sensitivity, long life, and low cost are currently desired.

Generally, selenium (S)
e) Inorganic materials such as cadmium sulfide (CdS), zinc oxide (ZnO), and amorphous silicon (a-Si) are used, but they do not necessarily satisfy the characteristics required for electrophotographic photoreceptors. I can't say. For example, selenium (Se) sufficiently satisfies the charging characteristics, but has drawbacks such as difficulty in processing into a film, and sensitivity to heat and mechanical shock, requiring careful handling. Amorphous silicon (a-Si) has a drawback that manufacturing conditions are difficult and manufacturing costs are high.

In recent years, various photoconductors using organic materials, such as butadiene compounds and oxadiazole compounds, which have eliminated the above-mentioned disadvantages, have been proposed, and some of them have been put to practical use. However, those containing a butadiene compound are effective for suppressing light fatigue, but have drawbacks in electrical characteristics, and those containing an oxadiazole compound as a main component have excellent electrical characteristics even if they have excellent electrical characteristics. There is a problem of fatigue.

On the other hand, in the case of a combination with a charge generation material, since a printer uses an LED or a semiconductor laser as a light source, a material having sensitivity to a relatively long wavelength in the near infrared region is required. An organic material satisfying this requirement is a phthalocyanine dye, which has been vigorously researched and developed.

In order to increase the sensitivity, a stacked photoreceptor using a phthalocyanine deposited film as a charge generation layer has been studied.
Some phthalocyanines having a group Ia or group IV metal as a central metal having relatively high sensitivity have been obtained. References relating to such metal phthalocyanines include, for example, JP-A-57-211149 and JP-A-57-148745.
No. 59-36254, No. 59-44054, No. 59
-30541, 59-31965 and 59-166959. However, the production of the vapor-deposited film requires a high-vacuum evacuation apparatus, and the equipment cost is high. Therefore, the organic photoreceptor as described above must be expensive.

On the other hand, using phthalocyanine not as a vapor deposition film but as a resin dispersion layer and using this as a charge generation layer,
A composite photoreceptor having a charge transfer layer coated thereon has also been studied. Such composite photoreceptors include metal-free phthalocyanine (Japanese Patent Application No. 57-66963) and indium phthalocyanine (Japanese Patent Application No. 59-6693). No. 220493), which are relatively high-sensitivity photoreceptors, but the former has the disadvantage that the sensitivity decreases rapidly in the long wavelength region of 800 nm or more, and the latter has a charge generation layer. In the case where is prepared in a resin dispersion system, it has disadvantages such as insufficient sensitivity when put into practical use.

In recent years, particularly, those using titanyl phthalocyanine having electrophotographic characteristics with relatively high sensitivity have been studied (JP-A-59-49544, JP-A-61-23928, JP-A-61-109056, It is known that there is a difference in characteristics depending on various crystal forms. In order to form these various crystal forms, special purification and special solvent treatment are required. The treatment solvent is different from that used when forming the dispersion coating film. These obtained various crystals, in the growth processing solvent, crystal growth is easy, when the same solvent is used as a coating solvent, the crystal form, the control of the particle size is difficult, there is no stability of the paint, as a result,
This is because the electrostatic characteristics are deteriorated and are not suitable for practical use. For this reason, usually a chlorine-based solvent such as chloroform is used to hardly promote crystal growth when forming a paint, but these solvents do not always have good dispersibility in titanyl phthalocyanine, and the dispersion stability of the paint is not sufficient. Is a problem.

In addition, titanyl phthalocyanine generally has a large ionization potential, and when used with a butadiene compound having a small ionization potential, the difference in ionization potential is large, so that injection of holes from titanyl phthalocyanine to the butadiene compound easily occurs, so that the chargeability is further deteriorated. Disadvantageously, the durability is poor.

The present invention has been made in view of the above-described drawbacks, and satisfies the above-mentioned various characteristics by combining organic photoconductive materials and improving the characteristics such as light fatigue, surface potential reduction due to repeated use, and high sensitivity. It is an object of the present invention to provide a stable electrophotographic photosensitive member.

[Means for Solving the Problems] The present invention includes a photosensitive layer containing a butadiene compound represented by the following general formula [I] and an oxadiazole compound represented by the following general formula [II]. An electrophotographic photoreceptor characterized in that:

(Wherein, R ^{1 to} R ⁴ represent an alkyl group, which may be the same or different from each other) (Wherein, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an acyl group or a cycloalkyl group, and may be the same or different from each other.) The present invention also includes a charge generation material and a charge transfer material. In the electrophotographic photoreceptor, (a) the charge-generating material is a metal-free phthalocyanine nitrogen isoform, a metal phthalocyanine nitrogen isoform, a metal-free phthalocyanine, a metal phthalocyanine, a metal-free naphthalocyanine, or a metal naphthalocyanine (provided that the metal-free phthalocyanine nitrogen The structure, the metal phthalocyanine nitrogen isoform, the metal-free phthalocyanine and the metal phthalocyanine may have a substituent on the benzene nucleus, and the metal-free naphthalocyanine and the metal naphthalocyanine may have a substituent on the naphthyl nucleus.) At least 50 parts by weight of a total of The titanyl phthalocyanine composition crystal containing 100 parts by weight of cysteine is used as an active ingredient, and the composition crystal has an infrared absorption spectrum of 14%.
90 ± 2cm ^-1 , 1415 ± 2cm ^-1 , 1332 ± 2cm ^-1 , 1119 ± 2cm ^-1 ,
1072 ± 2cm- ¹ , 1060 ± 2cm- ¹ , 961 ± 2cm- ¹ , 893 ± 2cm- ¹ ,
(B) a charge transfer material comprising a butadiene compound represented by the above general formula [I] and a butadiene compound represented by the above general formula [I], which has a characteristic strong absorption at 780 ± 2 cm ⁻¹ , 751 ± 2 cm ⁻¹ and 730 ± 2 cm ⁻¹ ; An electrophotographic photoreceptor comprising an oxadiazole compound represented by the general formula [II] as an active ingredient.

According to the present invention, by using the compounds represented by the above general formulas [I] and [II] in combination as the charge transfer material, the disadvantages of the butadiene compound and the oxdiazole compound as the charge transfer material are mutually reduced. Complemented. Furthermore, a titanyl phthalocyanine to which other phthalocyanines or naphthalocyanines compounds and the like described below are added, and a non-crystalline composition of the mixture is treated and crystallized with tetrahydrofuran, showing a novel infrared absorption spectrum, By combining a titanyl phthalocyanine composition crystal with excellent photoconductivity, the difference in ionization potential is also solved, high sensitivity and excellent chargeability, little light fatigue even after repeated use, and excellent durability A photographic photoreceptor is obtained.

 Hereinafter, the present invention will be described in detail.

Butadiene compound of general formula [I] and general formula [II]
Preferred specific examples of the oxadiazole compound are as follows.

The butadiene compound of the general formula [I] is preferably a compound in which all of R ^{1 to} R ⁴ are a methyl group or an ethyl group. [1,1-bis- (p-dimethylaminophenyl) -4,4-
Diphenyl-1,3-butadiene], [1,1-bis- (p-diethylaminophenyl) -4,4-
Diphenyl-1,3-butadiene].

Further, as the oxadiazole compound represented by the general formula [II], R ⁵ and R ⁶ are each one or up to three selected from the group consisting of a hydrogen atom, an alkyl group, an acyl group and a cycloalkyl group. Compounds are preferred. For example, [2,5-bis- (4-dimethylaminophenyl) -1,3,4
-Oxadiazole], [2,5-bis- (4-diethylaminophenyl) -1,3,4
-Oxadiazole], [2,5-bis- (4-n-propylaminophenyl)-
1,3,4-oxadiazole], [2,5-bis- (4-isoamylaminophenyl) -1,
3,4-oxadiazole], [2,5-bis- (4-cyclopentylaminophenyl)
-1,3,4-oxadiazole], [2,5-bis- (4-cyclohexylaminophenyl)
-1,3,4-oxadiazole], [2,5-bis (<4-di-n-propyl> -aminophenyl) -1,3,4-oxadiazole], [2,5-bis- (4-acetylaminophenyl) -1,3,4
-Oxadiazole], [2,5-bis- (4-acetylamino-2-chlorophenyl) -1,3,4-oxadiazole], [2,5-bis- (4- <n-propylamino> -2-chlorophenyl) -1,3,4-oxadiazole], [2,5-bis- (4-ethylaminophenyl) -1,3,4-
Oxadiazole], [2,5-bis- (4-N-ethyl-Nn-propyl-
Aminophenyl) -1,3,4-oxadiazole], [2,5-bis- (4- <N-ethyl-N-acetyl>-
Aminophenyl) -1,3,4-oxadiazole], [2- (4-diethyl-aminophenyl) -5- (4 ′
-Dimethyl-aminophenyl) -1,3,4-oxadiazole], [2- (4-dimethyl-aminophenyl) -5- (4 '
-Amino-3-chlorophenyl) -1,3,4-oxadiazole] [2- (4-mono-n-propyl-aminophenyl)-
5- (4'-dimethyl-aminophenyl) -1,3,4-oxadiazole], [2- (4-mono-n-propyl-aminophenyl)-
5- (4'-mono-ethyl-aminophenyl) -1,3,4
-Oxadiazole].

Among the above substances, butadiene compounds are especially 1,1
-Bis- (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene is preferred, and the oxadiazole compound is particularly preferably 2,5-bis- (4-diethylaminophenyl) -1,3,4- Oxadiazole is preferred.
These butadiene compounds and oxadiazole compounds are known prior to the present application and are each produced by a conventional method.

Next, the phthalocyanine compound used in the present invention,
Naphthalocyanine compounds are “Phthalocyanine compounds” from Moser and Thomas (Reinhold 196
3), and those obtained by known methods such as "phthalocyanine" (CRC Publishing, 1983) and other suitable methods.

For example, titanyl phthalocyanine can be easily synthesized from 1,2-dicyanobenzene (p-phthalodinitrile) or a derivative thereof and a metal or a metal compound according to a known method.

For example, in the case of titanyl phthalocyanines, they can be easily synthesized according to the following reaction formula (1) or (2).

(However, Pc represents a phthalocyanine residue.) As the organic solvent, nitrobenzene, quinoline, α-
High boiling organic solvents which are inert to the reaction of chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenylether, diphenylmethane, diphenylethane, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, etc. are preferred. The reaction temperature is usually from 150 to 300C, preferably from 200 to 250C.

In the present invention, the crude titanyl phthalocyanine compound thus obtained is used as it is or purified by the following method. In the case of purification, treatment with tetrahydrofuran is performed after non-crystallization treatment. At that time, after removing the organic solvent used for the condensation reaction using an appropriate organic solvent such as alcohols such as methanol, ethanol and isopropyl alcohol, and ethers such as tetrahydrofuran and 1,4-dioxane in advance, hot water Processing is preferred. In particular, the pH of the washing solution after hot water treatment is about 5
It is preferred to wash until it reaches ~ 7.

Subsequently, 2-ethoxyethanol, diglyme,
It is more preferable to treat with an electron-donating solvent such as dioxane, tetrahydrofuran, N, N-dimethylformamide, N-methylpyrrolidone, pyridine, and morpholine.

Next, as the phthalocyanine nitrogen isotope, there are various porphines, for example, tetrapyridinoporphyrazine in which one or more of the benzene nucleus of phthalocyanine is replaced with a quinoline nucleus, and the metal phthalocyanine includes
Examples include various substances such as copper, nickel, cobalt, zinc, tin, aluminum, and titanium.

In addition, examples of the substituent of phthalocyanines and naphthalocyanines include an amino group, a nitro group, an alkyl group, an alkoxy group, a cyano group, a mercapto group, and a halogen atom, and a sulfonic acid group, a carboxylic acid group, or a metal salt thereof. ,
Ammonium salts, amine salts and the like can be exemplified as relatively simple ones. Furthermore, various substituents can be introduced into the benzene nucleus via an alkylene group, a sulfonyl group, a carbonyl group, an imino group, etc., and these are conventionally known as an anti-aggregation agent or a crystal conversion inhibitor in the technical field of these conventional phthalocyanine pigments. (For example, see U.S. Pat. Nos. 3,973,981 and 4,088,507) or unknown. Known methods for introducing each substituent are omitted. In addition, those which are not publicly known are described as synthesis examples in Examples.

In the present invention, titanyl phthalocyanine and a metal-free and metal phthalocyanine nitrogen isoform which may have a substituent on a benzene nucleus, a metal-free and metal-free and metal naphthalocyanine which may have a substituent on a metal phthalocyanine or a naphthyl nucleus The composition ratio is preferably 100/50 (weight ratio) or more, but is desirably 100/20 to 0.1 (weight ratio).
And At 100 / 0.1 or more, the crystals contain many single crystals in addition to the mixed crystal composition, and the infrared absorption spectrum and X
In some cases, it is difficult to distinguish the novel material of the present invention from the line diffraction spectrum (hereinafter, these mixed compositions are referred to as titanyl phthalocyanine compositions).

The titanyl phthalocyanine composition of the present invention is obtained by mixing titanyl phthalocyanine and other phthalocyanines,
It can be produced by treating and crystallizing the non-crystalline composition of the mixture with tetrahydrofuran.

The amorphous titanyl phthalocyanine composition can be obtained by a single chemical method or mechanical method, but more preferably by a combination of various methods.

For example, non-crystalline particles can be obtained by weakening agglomeration between particles by a method such as an acid pasting method or an acid slurry method and then grinding by a mechanical treatment method. The equipment used during milling includes kneaders,
Banbury mixer, attritor, edge runner mill, roll mill, ball mill, sand mill, SPEX mill,
Examples include, but are not limited to, homomixers, dispersers, agitators, jaw crushers, stamp mills, cutter mills, micronizers, and the like. The acid pasting method, which is well known as a chemical treatment method, is a method in which a pigment is dissolved or sulfated in 95% or more sulfuric acid and poured into water or ice water to reprecipitate. Is desirably maintained at 5 ° C. or lower, and by slowly injecting sulfuric acid into water stirred at a high speed, amorphous particles can be obtained under even better conditions.

In addition, there are a method in which the crystalline particles are directly ground by a mechanical processing device for an extremely long time, a method in which the particles obtained by the acid pasting method are treated with the above-mentioned solvent and the like and then ground.

Amorphous particles can also be obtained by sublimation. For example,
Each raw material obtained by various methods under vacuum is 500 ~ 6
It can be obtained by sublimation by heating to 00 ° C. and promptly co-evaporation deposition on a substrate.

The amorphous titanyl phthalocyanine composition obtained as described above is treated in tetrahydrofuran,
Obtain new stable crystals. As a method for treating tetrahydrofuran, 5-300 parts by weight of tetrahydrofuran is added to 1 part by weight of the amorphous titanyl phthalocyanine composition in various stirring tanks, followed by stirring. The temperature can be either heating or cooling, but if heated, the crystal growth will be faster,
Also, it becomes slow at low temperatures. As the stirring tank, in addition to a usual stirrer, an ultrasonic ball mill, a sand mill, a homomixer, a disperser, an agitator, a micronizer, or the like, which is used for dispersion, or a mixer such as a concal blender V-type mixer is appropriately used. Used, but not limited to.

After these stirring steps, filtration, washing and drying are usually performed to obtain stabilized titanyl phthalocyanine composition crystals. At this time, a resin or the like can be added to the dispersion liquid as required without filtering and drying, and the dispersion can be made into a coating. When used as a coating film of an electrophotographic photoreceptor or the like, the process is omitted and it is extremely effective.

FIG. 1 shows the infrared absorption spectrum of the titanyl phthalocyanine composition of the present invention thus obtained. The titanyl phthalocyanine composition has an absorption wave number (cm ⁻¹ , including an error of ± 2) of 1490, 1415, 1332,
It shows characteristic strong peaks at points 1119, 1072, 1060, 961, 893, 780, 751, and 730.

FIG. 2 shows an X-ray diffraction pattern using CuK rays. This titanyl phthalocyanine composition showed the maximum diffraction peak at 27.3 degrees in the X-ray diffraction diagram at a Bragg angle 2θ (including an error range of ± 0.2 degrees), and 9.7
Degree, 24.1 degree shows strong peak, 27.3 degree shows maximum peak, 7.4 degree, 22.3 degree, 24.1 degree, 25.3 degree, 28.5 degree
Some show extremely strong peaks. It is considered that these differences are generally attributable to the fact that the intensity of the diffraction line is substantially proportional to the size of each crystal face, so that the degree of growth of each crystal face of the same structure crystal is different.

The titanyl phthalocyanine composition of the present invention is a very stable and excellent crystal which does not show a large change in the infrared absorption spectrum even when the crystal growth is promoted by further heating and stirring in tetrahydrofuran.

The electrophotographic photoreceptor of the present invention is preferably formed by laminating an undercoat layer, a charge generation layer and a charge transfer layer in this order on a conductive substrate, but in the order of an undercoat layer, a charge transfer layer and a charge generation layer. A laminate may be used, or a charge generation material and a charge transfer material may be dispersedly coated with an appropriate resin on an undercoat layer. Further, these undercoat layers can be omitted as necessary.

The charge transfer layer of the electrophotographic photoreceptor of the present invention comprises a butadiene compound of the general formula [I] (hereinafter referred to as butadiene) and an oxadiazole compound of the general formula [II] (hereinafter referred to as oxadiazole). Is dissolved in a suitable solvent together with a resin (binder), and if necessary, various additives such as a photoconductive substance which absorbs light to generate an electric charge, a sensitizing dye, an electron absorbing material or a plasticizer are added. It can be prepared by applying a coating solution obtained by addition to a conductive substrate, drying the coating solution, and forming a photosensitive layer (charge transfer layer) having a thickness of usually 5 to 30 μm.

The resin used for the charge transfer layer is silicon resin, ketone resin, polymethyl methacrylate, polyvinyl chloride,
Acrylic resin polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber and other insulating resins, poly-N-vinyl carbazole,
Polyvinyl anthracene, polyvinyl pyrene and the like are used.

The amount of the mixture of the butadiene of the general formula [I] and the oxadiazole of the general formula [II] is 2 parts per 100 parts by weight of the resin.
A suitable range is 0 to 300 parts by weight, preferably 50 to 200 parts by weight. Further, the ratio (mixing ratio) of butadiene and oxadiazole is 10 to 2000 parts by weight, preferably 50 to 1000 parts by weight, based on 100 parts by weight of butadiene. These resins may be used alone or in combination of two or more.

The coating method is performed using an apparatus such as a spin coater, an applicator, a spray coater, a bar coater, an immersion coater, a doctor blade, a roller coater, a curtain coater, and a bead coater.
μm, preferably 10 to 20 μm.

By dissolving the titanyl-based phthalocyanine composition crystal according to the present invention in a suitable solvent together with a suitable resin as a charge generating agent, it is possible to obtain a charge generating layer with extremely good dispersibility and extremely high photoelectric conversion efficiency. .

Coating is performed using a spin coater, an applicator, a spray coater, a bar coater, an immersion coater, a doctor blade, a roller coater, a curtain coater, a bead coater device, and drying is desirably heated to 40 to 200 ° C. for 10 minutes. Perform under static or blast conditions for up to 6 hours. The film thickness after drying is 0.01 to 5 μm, preferably
Coating is performed so as to be 0.1 to 1 μm.

As the resin that can be used when forming the charge generation layer by coating, a wide range of insulating resins can be selected.
It can be selected from organic photoconductive polymers such as N-vinyl carbazole, polyvinyl anthracene and polyvinyl pyrene. Preferably, polyvinyl butyral, polyarylate (such as a condensation polymer of bisphenol A and phthalic acid),
Polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinyl pyridine, cellulose resin, urethane resin, epoxy resin, silicone resin, polystyrene, polyketone, polyvinyl chloride, polyvinyl chloride, vinyl acetate Examples thereof include insulating resins such as coalescing, polyvinyl acetal, polyacrylonitrile, phenol resin, melamine resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The amount of the resin contained in the charge generation layer is 100% by weight or less, preferably 40% by weight or less. These resins may be used alone or in combination of two or more.

The solvent for dissolving these resins differs depending on the type of the resin, and is preferably selected from those which do not affect the charge generation layer and the undercoat layer during coating. Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin, monochlorobenzene and dichlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol, ethanol and isopropanol, and ethyl acetate and methyl cellosolve. Esters, carbon tetrachloride, aliphatic halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, and trichloroethylene; ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether;
Amides such as N-dimethylformamide and N, N-dimethylacetamide, and sulfoxides such as dimethyl sulfoxide are used.

Further, as the charge generating material, not only the titanyl phthalocyanine composition crystal described above, but also a known photoconductive material, that is, an inorganic material such as Se, Se-Te alloy, Se-As alloy, CdS, ZnO, or Cu, Al Phthalocyanines containing metals such as, In, Ti, Pb, and V, and organic materials such as metal-free phthalocyanines, chlorodians, azo-based pigments, bisazo-based pigments, and cyanine-based pigments, alone or as a mixture of two or more. Useful to use.

In addition to these various types, an undercoat layer can be provided on the conductive substrate for the purpose of preventing a decrease in chargeability and improving adhesion. As the undercoat layer, alcohol-soluble polyamides such as nylon 6, nylon 66, nylon 11, nylon 610, copolymerized nylon, and alkoxymethylated nylon, casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, gelatin, polyurethane, Metal oxides such as polyvinyl butalal and aluminum oxide are used. It is also effective to include conductive particles such as metal oxides and carbon black in the resin.

The thickness of the undercoat layer is 0.1 to 5 μm, preferably
About 0.4 to 3 μm is appropriate.

The electrophotographic photoreceptor of the present invention has an absorption peak at a wavelength near 800 nm as shown in the spectral sensitivity characteristic diagram of FIG. 4, and is used not only as an electrophotographic photoreceptor in copiers and printers but also in solar cells. It is also suitable as a photoelectric conversion element and an absorbing material for optical disks.

[Examples] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples unless it exceeds the gist. In the examples, parts are parts by weight.

Production of Phthalocyanines Synthesis Example 1 After 20.4 parts of o-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated and reacted in 50 parts of quinoline at 200 ° C. for 2 hours, the solvent was removed by steam distillation, followed by a 2% aqueous hydrochloric acid solution. The product was purified with a 2% aqueous sodium hydroxide solution, washed with methanol and N, N-dimethylformamide, and dried to obtain 21.3 parts of titanyl phthalocyanine (TiOPc).

Synthesis Example 2 14.5 parts of aminoiminoisoindolenine was heated in 50 parts of quinoline at 200 ° C. for 2 hours. After the reaction, the solvent was removed by steam distillation, and the mixture was purified with a 2% aqueous hydrochloric acid solution and subsequently with a 2% aqueous sodium hydroxide solution. After that, the resultant was sufficiently washed with methanol and N, N-dimethylformamide, and dried to obtain 8.8 parts of metal-free phthalocyanine (yield: 70%).

Synthesis Example 3 20 parts of o-naphthalodinitrile were added to 50 parts of quinoline in 200 parts.
After heating at 4 ° C. for 4 hours, the reaction mixture was purified with a 2% aqueous hydrochloric acid solution, washed with methanol and N, N-dimethylformamide, and dried to obtain 15 parts of a metal-free naphthalocyanine.

Production of Electrophotographic Photoreceptor Example 1 1 part of titanyl phthalocyanine obtained in Synthesis Example 1 and 0.05 part of metal-free phthalocyanine obtained in Synthesis Example 2 were gradually dissolved in 30 parts of 98% sulfuric acid at 5 ° C. Allow the mixture for about 1 hour,
Stir while keeping the temperature below 5 ° C. Subsequently, the sulfuric acid solution is slowly poured into 500 parts of ice water with high-speed stirring, and the precipitated homogeneous composition is filtered. This is washed with distilled water until no acid remains, to obtain a wet cake. The cake (assuming an amount of phthalocyanine contained of 1 part) was stirred in 100 parts of tetrahydrofuran for about 1 hour, filtered and washed with tetrahydrofuran to give a pigment content of 0.95 parts.
Part of the titanyl phthalocyanine composition crystal in tetrahydrofuran dispersion was obtained. After drying partially, the infrared absorption spectrum and the X-ray diffraction image were examined. As a result, the infrared absorption spectrum was the same as FIG. 1, and the X-ray diffraction pattern was as shown in FIG.

Next, 1.5 parts by dry weight of this composition, 1 part of butyral resin (BX-5, manufactured by Sekisui Chemical) and tetrahydrofuran (TH
F) The paint was prepared using an ultrasonic disperser so as to have 80 parts. This dispersion is applied to a polyamide resin (CM-8000 manufactured by Toray)
Has a dry film thickness of 0.2 on an aluminum plate coated with 0.5 μm
It was applied to a thickness of μm to obtain a charge generation layer. As a result of examining the infrared absorption spectrum and X-ray diffraction at this time, the results were as shown in FIG. 1 and FIG.

Further, as a charge transfer agent, 1,1-bis- (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene which is the butadiene compound (b) of the above general formula [I] is used.
70 parts, 2,5-bis- (4-diethylaminophenyl) -1, an oxadiazole compound (d) of the general formula [II],
30 parts of 3,4-oxadiasol, 100 parts of polycarbonate resin (Z-200 manufactured by Mitsubishi Gas Chemical Company) and 2,4-bis-
(N-octylthio) -6- (4-hydroxy-3,5-
A solution prepared by dissolving 10 parts of di-t-butylanilino) -1,3,5-triazine in 500 parts of a toluene / THF (1/1) mixed solution was applied to a dry film thickness of 15 μm to form a charge transfer layer. Formed.

Thus, an electrophotographic photosensitive member having a laminated photosensitive layer was obtained. The half-life exposure amount (E _1/2 ) of this photoreceptor was measured by an electrostatic copying paper test apparatus (EPA-8100, Kawaguchi Electric Works). That is, it was charged by a corona discharge of -5.5 kV in a dark place, and then exposed to white light with an illuminance of 5 lux, and the exposure amount E _1/2 (lux · sec) required to attenuate to half the surface potential was determined. .

Example 2 On the charge generation layer used in Example 1, a butadiene compound (b) of the general formula [I] was used as a charge transfer layer.
90 parts of 1,1-bis- (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene and 2,5-bis- (4) which is an oxadiazole compound (f) of the general formula [II] -Isoamylaminophenyl) -1,3,4-oxadiazole 1
0 parts, 80 parts of a polycarbonate resin and 30 parts of 2-hydroxy-4-methoxybenzophenone were added to 500 parts of dichloromethane.
An electrophotographic photoreceptor was prepared and measured in the same manner as in Example 1 except that the solution dissolved in the portion was used.

Example 3 An oxadiazole compound (i) was used instead of the oxadiazole compound (f) used in Example 2 above.
Example 2 except that 5-bis-(<4-di-n-propyl> -aminophenyl) -1,3,4-oxadiazole was used.
A photoreceptor was prepared in the same manner as described above.

Example 4 An oxadiazole compound (j) was used instead of the oxadiazole compound (f) used in Example 2 above.
A photoconductor was prepared by the same method as that of Example 2 except that 5-bis- (4-acetylaminophenyl) -1,3,4-oxadiazole was used.

Example 5 On the charge generation layer used in Example 1, a 1,1-butadiene compound (a) of the general formula [I] was used as a charge transfer layer.
Bis- (p-dimethylaminophenyl) -4,4-diphenyl-1,3-butadiene 75 parts, 2,5-bis-(<4-di-oxadiazole compound (i) of the general formula [II] −
A photoconductor was prepared in the same manner as in Example 1, except that a solution prepared by dissolving 25 parts of (n-propyl> -aminophenyl) -1,3,4-oxadiazole and 90 parts of a polycarbonate resin in 600 parts of dichloromethane was used. did.

Example 6 An oxadiazole compound (m) was used in place of the oxadiazole compound (i) used in Example 5 above.
A photoconductor was prepared by the same method as that of Example 5 except that 5-bis- (4-ethylaminophenyl) -1,3,4-oxadiazole was used.

Example 7 2,5-bis- (4- <N-ethyl-N-acetyl> -aminophenyl) which is an oxadiazole compound (o) in place of the oxadiazole compound (i) used in Example 5 Example 5 except for using 1,3,4-oxadiazole
A photoreceptor was prepared in the same manner as described above.

Example 8 A sample was prepared in the same manner as in Example 1 except that 0.05 part of the metal-free naphthalocyanine obtained in Synthesis Example 3 was used instead of 0.05 part of the metal-free phthalocyanine of Example 1, and the infrared absorption spectrum was measured. It was confirmed that this was the same as FIG.

Then, 1,1-bis- (p-diethylaminophenyl)-, a butadiene compound (b) of the general formula [I], was formed as a charge transfer layer on the charge generation layer formed in the same manner as in Example 1 using the same. 4,4-diphenyl-1,3-butadiene 70
Part, 2,5-bis- (4-ethylaminophenyl) -1,3,4-, which is an oxadiazole compound (m) of the general formula [II]
Oxadiazole 30 parts, polycarbonate resin 100 parts,
2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine 10 parts and 2-hydroxy-4-methoxybenzophenone 5 parts A photoreceptor was prepared and measured in the same manner as in Example 1 except that a solution prepared by dissolving in a toluene / THF (1/1) mixed solution (500 parts) was used.

Comparative Example 1 A solution comprising 100 parts of a butadiene compound (b), 100 parts of a polycarbonate resin (Z-200) and 500 parts of a toluene / THF (1/1) mixed solution was applied onto the charge generation layer used in Example 1. A photoconductor was prepared and measured.

Comparative Example 2 A photoconductor was prepared by the same way as that of Comparative Example 1 except that the oxadiazole compound (d) was used instead of the butadiene compound (b).

Comparative Example 3 10 parts of a butadiene compound (b), 90 parts of p-dimethylaminobenzaldehyde- (diphenylhydrazone), a hydrazone compound, 100 parts of a polycarbonate resin (Z-200) and 500 parts of dichloromethane were provided on the charge generation layer used in Example 1. To prepare a photoreceptor coated with a solution consisting of

Comparative Example 4 A photoconductor was prepared by the same way as that of Comparative Example 3 except that the oxadiazole compound (d) was used instead of the butadiene compound (b).

Table 1 shows the results of evaluating various characteristics of the electrophotographic photosensitive members manufactured in Examples 1 to 8 and Comparative Examples 1 to 4 as described in Example 1.

V ₀ : Surface potential (-5.5 KV) E _1/2 : Half exposure DDR1: Dark decay rate (initial) DDR2: 〃 (after 1000 cycles) V ₀ 1: Initial charging potential V ₀ 2: Charging after 1000 cycles Potential VR1: Initial residual potential VR2: Residual potential after 1000 cycles As is clear from Table 1 above, in Comparative Example 1, the fluctuation of the dark decay rate (DDR2) due to repeated use is large, and the surface potential (V ₀ 2) There is a disadvantage that the reduction is large. In the photoreceptor of Comparative Example 2, the change in the dark decay rate is small, but the increase in the residual potential (VR2) due to repeated use is large. This indicates that the use of a butadiene compound or an oxadiazole compound alone is not suitable for a photoreceptor. Also in the photoconductors of Comparative Examples 3 and 4, characteristic deterioration due to repeated use is observed.

The photoreceptors of Examples 1 to 8 using the two components of the butadiene compound and the oxadiazole compound of the present invention have good repetition characteristics such as stable dark decay rate and surface potential and small rise in residual potential. It turns out to be something. Further, by using a titanyl phthalocyanine composition crystal as a material for the charge generation layer and combining it with the above-described charge transfer material, it is possible to obtain a coating having good dispersion and a stable crystal type and a long life, so that uniform film formation is easy. This is useful in the production of a photoreceptor.

[Effects of the Invention] As described above, the electrophotographic photoreceptor of the present invention has a stable dark decay rate and a stable surface potential, and has good repetition characteristics. Therefore, the electrophotographic photoreceptor of the present invention has high photosensitivity to a laser wavelength range and is particularly effective as a high-speed, high-quality printer photoreceptor.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of a titanyl phthalocyanine composition crystal used as a charge generation material of the present invention,
FIG. 2 is an X-ray diffraction pattern thereof, FIG. 3 is an X-ray diffraction pattern in the state of the coating film, and FIG. 4 is a spectral sensitivity characteristic diagram of the electrophotographic photosensitive member obtained according to one embodiment of the present invention.

Claims (2)

(57) [Claims] 1. An electrophotographic photosensitive member comprising a photosensitive layer containing a butadiene compound represented by the following general formula [I] and an oxadiazole compound represented by the following general formula [II]. body. (Wherein, R ^{1 to} R ⁴ represent an alkyl group, which may be the same or different from each other) (Wherein, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an acyl group or a cycloalkyl group, and may be the same or different from each other) 2. An electrophotographic photoreceptor containing a charge generating material and a charge transfer material, wherein: (a) the charge generating material is a metal-free phthalocyanine nitrogen isoform, a metal phthalocyanine nitrogen isoform, a metal-free phthalocyanine, a metal phthalocyanine, a metal-free Naphthalocyanine or metal naphthalocyanine (however, metal-free phthalocyanine nitrogen isoform, metal phthalocyanine nitrogen isoform, metal-free phthalocyanine and metal phthalocyanine may have a substituent on the benzene nucleus, and metal-free naphthalocyanine and metal naphthalocyanine Phthalocyanine may have a substituent on the naphthyl nucleus), and a total of 50 parts by weight or less of a titanyl phthalocyanine composition crystal containing 100 parts by weight of titanyl phthalocyanine as an active ingredient; The composition crystal has an infrared absorption spectrum of 14
90 ± 2cm ^-1 , 1415 ± 2cm ^-1 , 1332 ± 2cm ^-1 , 1119 ± 2cm ^-1 ,
1072 ± 2cm- ¹ , 1060 ± 2cm- ¹ , 961 ± 2cm- ¹ , 893 ± 2cm- ¹ ,
(B) a charge transfer material comprising a butadiene compound represented by the following general formula [I] and a butadiene compound represented by the following general formula [I]: 780 ± 2 cm ⁻¹ , 751 ± 2 cm ^−1, and 730 ± 2 cm ⁻¹ An electrophotographic photoreceptor comprising an oxadiazole compound represented by the general formula [II] as an active ingredient. (Wherein, R ^{1 to} R ⁴ represent an alkyl group, which may be the same or different from each other) (Wherein, R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group, an acyl group or a cycloalkyl group, and may be the same or different from each other)