JPH0572775A - Electrophotographic photoreceptor - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an electrophotographic photoreceptor using a metal-free phthalocyanine having excellent electrophotographic characteristics. [Structure] The present invention relates to an electrophotographic photoreceptor using a metal-free phthalocyanine prepared by adding the following compound such as hemimellitic acid during synthesis as a charge generating material. By this method, τ type metal-free phthalocyanine could be synthesized in one step. Further, the electrophotographic properties of the τ-type metal-free phthalocyanine were better than those of the conventional α-type metal-free phthalocyanine which was subjected to crystal transition by milling.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an electrophotographic photosensitive member using a metal-free phthalocyanine having excellent electrophotographic characteristics.

[0002]

2. Description of the Related Art Conventional electrophotographic photoreceptors are selenium,
Inorganic photoconductors such as selenium alloys, zinc oxide, cadmium sulfide and tellurium have been mainly used. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost, and they have begun to be used as light sources for electrophotography. Therefore, it is not suitable to use the material having sensitivity in the short wavelength region, which has been used up to now, for the semiconductor laser, and the long wavelength region (760 nm
Above, it has become necessary to develop materials with high sensitivity. Recently, active research has been conducted on laminated organic photoconductors using organic materials, particularly phthalocyanine having a large absorption in the long wavelength region. For example, as the charge generation material, X-type metal-free phthalocyanine (X-H ₂ Pc), τ-type metal-free phthalocyanine (τ-H ₂ Pc), divalent metal phthalocyanine is ε-type copper phthalocyanine (ε-CuPc).
Has sensitivity in the long wavelength region. As the trivalent or tetravalent metal phthalocyanine, chloroaluminum phthalocyanine (A
1PcCl), chlorogallium phthalocyanine (GaP
cCl), chloroindium phthalocyanine (InPc
Cl), vanadium phthalocyanine (VOPc) and titanium phthalocyanine (TiOPc) have been actively studied (Japanese Patent Laid-Open Nos. 57-39484 and 57-57).
166959, JP-A-59-36254, JP-A-5
9-204045, etc.). However, materials up to the present have had problems in electrophotographic sensitivity, chargeability, dark decay, electrophotographic characteristics during repeated use, and image stability.
Among them, metal-free phthalocyanine is a material having high chargeability and excellent stability. Τ-H with high electrophotographic characteristics
_In order to obtain ₂ Pc, it is necessary to undergo a crystal transition from β type through α type in the crude synthesis stage, and many steps are required. Impurities mixed in each step deteriorate electrophotographic characteristics. It was one of the causes. .. As described above, there are still few practical charge generating agents having high sensitivity in the oscillation wavelength region of semiconductor lasers, and their development is awaited at present. Light emitting diode (LED) as light source for printer
Is also used, and its oscillation wavelength is around 650 nm. The phthalocyanine compound has a large absorption around 650 nm, and is expected as a charge generation material for LEDs.

[0003]

SUMMARY OF THE INVENTION The present invention is an electrophotographic photoreceptor using a metal-free phthalocyanine obtained by a specific synthesis method, and using this compound as a charge generating agent, excellent exposure sensitivity characteristics and wavelength are obtained. Another object is to obtain an electrophotographic photosensitive member having, in addition to the characteristics, deterioration resistance characteristics during repeated use over a long period of time, printing durability, and image stability.

[0004]

The present invention is characterized in that in an electrophotographic photosensitive member comprising a charge generating agent on a conductive support, the charge generating agent is the present metal-free phthalocyanine compound. It is an electrophotographic photoreceptor. The metal-free phthalocyanine of the present invention is reacted in the presence of phthalic acid, phthalodinitrile, isoindolenin and / or a derivative thereof, copper or a compound thereof, and a compound represented by the general formula (1) in an inert organic solvent. The obtained metal-free phthalocyanine is at least one of τ, modified τ, η and modified η type. General formula (1)

[0005]

[Chemical 2]

[In the formula, X _{1 to} X ₃ represent a hydrogen atom, an alkyl group, an allyl group, a carboxyl group, or a group derived from them. Y _{1 to} Y ₃ represent a carboxyl group, a nitro group and / or a group derived from them. X and Y may be the same or different, and Y may be ring-closed with two or more groups to form an imide or an acid anhydride. ]

Further, phthalic acid, phthalodinitrile,
In the presence of isoindolenine and / or a derivative thereof, copper or a compound thereof, a compound represented by the general formula (1),
An electrophotographic photoreceptor, which is a copper phthalocyanine obtained by adding a phthalocyanine derivative when the reaction is carried out in an inert organic solvent. Examples of the compound represented by the general formula (1) include benzene-1,2,3-tricarboxylic acid (hemimellitic acid), benzenehexacarboxylic acid (mellitic acid) and benzene-1,2,4-tricarboxylic acid (trimellitic acid). Acid), but is not limited thereto. Further, on the electroconductive support, in an electrophotographic photoreceptor comprising a charge generating agent and a charge transporting agent, the charge generating agent is the present copper phthalocyanine compound,
An electrophotographic photosensitive member characterized in that the charge transport material is at least one of a hydrazone derivative and a butadiene derivative or a hole transporting resin.

The organic solvent used in the present invention is α
A reaction-inert high boiling point solvent such as -chloronaphthalene, ethylene glycol, dialkyl ether, quinoline, sulfolane and dichlorobenzene is preferable. The synthesized metal-free phthalocyanine crude is acid, alkali, acetone, methyl ethyl ketone, tetrahydrofuran, pyridine, quinoline, sulfolane, α-chlornaphthalene, toluene, dioxane, xylene, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, trichloropropane, N ,. N'-dimethylacetamide,
It is obtained by purification with N-methylpyrrolidone, N, N'-dimethylformamide and the like. Examples of the purification method include solvent washing, recrystallization method, Soxhlet extraction method and hot suspension method. It is also possible to purify by sublimation. The purification method is not limited to these. Normally, τ type, which has the highest photoconductivity among metal-free phthalocyanines, is transferred to τ type by mechanical grinding method of α-type metal-free phthalocyanine. Was difficult. However, the present invention succeeded in obtaining a metal-free phthalocyanine having a required crystal form by one-step synthesis and having a small crystal grain size. The phthalocyanine derivative used in the present invention contains a metal-free or metal phthalocyanine having a substituent on at least one benzene nucleus in one molecule of phthalocyanine.

The charge-generating layer using the metal-free phthalocyanine produced by the above method is a uniform layer having a high light absorption efficiency, and the charge-generating layer can be formed between particles of the pigment, between the charge-generating layer and the charge-transporting layer. Since there are few voids between the photosensitive layer and the undercoat layer or the conductive substrate, the electrophotographic photoreceptor satisfies many requirements such as stability of potential and sensitivity during repeated use, clear printed images, and printing resistance. I was able to get The n-type photoreceptor is generally produced by laminating an undercoat layer, a charge generation layer, and a charge transport layer in this order on a conductive substrate. Further, the p-type photoreceptor is one in which a charge transport layer and a charge generation layer are laminated in this order on a conductive substrate or an undercoat layer. Alternatively, it may be prepared by adding a charge generating agent and an appropriate resin, and if necessary, a charge transporting agent, to a conductive substrate or an undercoating layer, followed by dispersion coating. If necessary, the photoreceptor may be provided with an overcoat layer for the purpose of protecting the surface from active gas and preventing filming by toner. The metal-free phthalocyanine of the present invention is used for all of the above photoconductors.
The coating of the charge generation layer of the photoreceptor is performed using a spin coater, an applicator, a spray coater, a dip coater, a roller coater, a curtain coater, a bead coater, etc., and drying is performed at room temperature to 200 ° C. for 10 minutes to 6 hours. Perform under static or blast conditions. The thickness of the film after drying is 0.01 to 5 μm, preferably 0.1 to 1 μm.

The resin used when forming the charge generation layer can be selected from a wide range of insulating resins. Also, poly-N
It can also be selected from organic photoconductive polymers such as vinylcarbazole, polyvinylanthracene and polysilanes. Preferably, polyvinyl butyral, polyarylate, polycarbonate, polyester, phenoxy, acrylic, polyamide, urethane, epoxy, silicone,
Insulating resins such as polystyrene, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, phenol and melamine resin can be mentioned. The resin contained in the charge generation layer is preferably 100% by weight or less, but not limited to this. You may use resin in combination of 2 or more types. Further, if necessary, the resin may not be used. The solvent used when forming the charge generation layer is preferably selected from those which do not affect the undercoat layer or the charge transport layer. Specifically, aromatic hydrocarbons such as benzene and xylene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol and ethanol, esters such as ethyl acetate and methyl cellosolve, carbon tetrachloride, chloroform and dichloromethane. , But are not limited to, aliphatic halogenated hydrocarbons such as dichloroethane and trichloroethylene, aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene, ethers such as tetrahydrofuran and dioxane, and the like. The charge transport layer is formed by dissolving the charge transport agent alone or in a resin. The charge transport agent used in the present photoreceptor may be any type of compound as long as it is a compound capable of transporting charges, but one or more compounds selected from hydrazone compounds and styryl compounds are desirable. .. Two or more types of charge transport materials can be used in combination. The resin that can be used for the charge transport layer can be selected from those described as the resin for the charge generation layer. The coating method can be the same as that for the charge generation layer. The film thickness after drying is 5 to 50 μm, preferably 15 to 25 μm.

As the undercoat layer, resins such as polyamides, casein, polyvinyl alcohol, gelatin, polyvinyl butyral, and metal oxides such as aluminum oxide are used. The material of the present invention is not only used as an electrophotographic photosensitive member in a copying machine or a printer, but also as a solar cell, a photoelectric conversion element, an electroluminescence (E
It is also suitable as an L) element and an absorbing material for an optical disc.

[0012]

EXAMPLES Examples of the present invention will be specifically described.
In the examples, “part” means “part by weight”. Example 1 30 parts phthalic anhydride, 48 parts urea and meritic acid
26 parts are heated and stirred in 230 parts of sulfolane at 230 ° C. for 15 hours. After cooling to 100 ° C. or lower, it is washed with 250 parts of 60 ° C. hot water. Then, reslurry in 500 parts of 2% hydrochloric acid, stir at 60 ° C. for 1 hour, and filter to 2
3.0 parts of τ-type metal-free phthalocyanine was obtained. Example 2 Synthesis and purification was carried out in the same manner as in Example 1 except that 30 parts of phthalonitrile, 1.26 parts of hemimellitic acid, and 230 parts of sulfolane were used as raw materials, and then 22.
1 part of modified τ type metal-free phthalocyanine was obtained. Example 3 20.3 parts of τ-type metal-free phthalocyanine was synthesized and purified in the same manner as in Example 1 except that 35 parts of 2-aminoiminoisoindolenine was used instead of 30 parts of phthalonitrile. Obtained. Examples 4 to 6 As a synthetic additive, the phthalocyanine derivative 1 shown in Table 1 was used.
By the same method as in Example 1 except that parts were used, 22.1, 23.0 and 20.5 parts of η-type metal-free phthalocyanine were obtained in order.

Table 1

[Table 1]

Example 7 23.4 parts of metal-free phthalocyanine was obtained by synthesis and purification in the same manner as in Example 1 except that τ type metal-free phthalocyanine was used as an additive at the time of synthesis. Comparative Example 1 30 parts of phthalic anhydride and 48 parts of urea were added to sulfolane 230.
The mixture is heated and stirred at 230 ° C for 15 hours. After cooling to 100 ° C. or lower, it is washed with 250 parts of 60 ° C. hot water. Next, it was reslurried in 500 parts of 2% hydrochloric acid, stirred at 60 ° C. for 1 hour, and then filtered to obtain 20.0 parts of β-type metal-free phthalocyanine crude. 20 parts of this metal-free phthalocyanine crude is gradually dissolved in 98% sulfuric acid and stirred. Subsequently, this sulfuric acid solution is poured into 8000 parts of water to precipitate crystals. The crystals were washed with distilled water until no acid remained, to obtain 19 parts of α-type copper phthalocyanine. 10 parts of this α-type metal-free phthalocyanine was crystallized together with 60 parts of diethylene glycol in a ball mill for 30 hours to form a τ-type crystal transition, and then washed to obtain 9.5 parts of τ-type metal-free phthalocyanine.

Next, a method for producing an electrophotographic photosensitive member using the metal-free phthalocyanine prepared in Examples and Comparative Examples as a charge generating agent will be described. Copolymerized nylon (Amilan CM-8000; manufactured by Toray Industries, Inc.) 10 parts ethanol 1
After mixing with 90 parts by a ball mill for 3 hours, the coating solution is applied with a wire bar onto a sheet obtained by vapor-depositing aluminum on a polyethylene terephthalate (PET) film. After drying, a sheet having an undercoat layer having a film thickness of 0.5 micron was obtained. After 2 hours of ball milling 2 parts of metal-free phthalocyanine, 97 parts of tetrahydrofuran and 1 part of polyvinyl butyral resin (BH-3; manufactured by Sekisui Chemical Co., Ltd.)
Was dispersed in a ball mill for 6 hours together with the dissolved resin liquid.
This dispersion was applied onto the undercoat layer and dried to form a charge generation layer having a thickness of 0.3 μm. Using the hydrazone derivative (2) or the butadiene derivative (3) as a charge transport agent, 1 part of the charge transport agent and 1 part of a polycarbonate resin (Panlite K-1300; Teijin Chemicals Ltd.) were mixed and dissolved in 8 parts of dichloromethane. This coating solution was applied onto the charge generation layer and dried, and then a charge transport layer having a film thickness of 20 μm was formed, and its electrophotographic characteristics were measured. In addition, poly (methylphenylsilylene), which is a hole-transporting resin
When (PMPS) was used, the resin alone was used to form a charge transport layer having a thickness of 20 μm.

[0016]

[Chemical 3]

[0017]

[Chemical 4]

The electrophotographic characteristics of the photoconductor were measured by the following methods. Static mode 2, by an electrostatic copying paper tester (EPA-8100; manufactured by Kawaguchi Electric Co., Ltd.)
Corona charging is -5.2 (kV), 1 (μW) 780n
The half-exposure sensitivity (E1 / 2) was examined from the time when the charge amount was reduced to 1/2 of the initial amount by irradiating m monochromatic light.

Table 2

[Table 2]

From the results shown in Table 2, the photoconductors using the metal-free phthalocyanine of the Examples have good electrophotographic characteristics such as chargeability and sensitivity, and show high sensitivity even in the semiconductor laser wavelength region of 760 nm or more. there were. From the above results, the electrophotographic photoreceptor using the metal-free phthalocyanine of the present invention as a charge generating agent was a photoreceptor having excellent electrophotographic characteristics.

[0021]

By using the metal-free phthalocyanine synthesized according to the present invention as the charge generating material, an electrophotographic photoreceptor having excellent electrophotographic characteristics could be obtained.

Front page continuation (72) Inventor Naoki Sato 2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A charge generating agent is reacted in an inert organic solvent in the presence of phthalic acid, phthalodinitrile, isoindolenin and / or a derivative thereof, and a compound represented by the following general formula (1). An electrophotographic photosensitive member, which is the obtained metal-free phthalocyanine. General formula (1) [In the formula, X _{1 to} X ₃ are a hydrogen atom, an alkyl group, an allyl group,
It represents a carboxyl group or a group derived from them. Y _{1 to} Y ₃ represent a carboxyl group, a nitro group and / or a group derived from them. X and Y may be the same or different, and Y may be ring-closed with two or more groups to form an imide or an acid anhydride. ] 2. The electrophotographic photosensitive member according to claim 1, wherein the metal-free phthalocyanine obtained by the reaction is at least one of τ, modified τ, η and modified η type. 3. A phthalocyanine derivative is added when the reaction is carried out in an inert organic solvent in the presence of phthalic acid, phthalodinitrile, isoindolenin and / or a derivative thereof, and a compound represented by the general formula (1). An electrophotographic photoreceptor comprising the metal-free phthalocyanine according to claim 1 or 2 obtained as described above. 4. A phthalocyanine is added when reacting in the presence of phthalic acid, phthalodinitrile, isoindolenin and / or a derivative thereof, a compound represented by the general formula (1) in an inert organic solvent. An electrophotographic photoreceptor comprising the obtained metal-free phthalocyanine according to claim 1 or 2. 5. An electrophotographic photoreceptor comprising a charge generating agent and a charge transporting agent on a conductive support, wherein the charge generating agent is the metal-free phthalocyanine compound according to claim 1. An electrophotographic photoreceptor characterized in that the charge transport agent is at least one of a hydrazone derivative and a butadiene derivative or a hole transporting resin.