JPS63189872A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve an exposing photosensitive characteristic and wavelength characteristic by incorporating specific nonmetallic phthalocyanines and the compd. satisfying the specific general formula into the electric charge generating layer and charge transfer layer, respectively, which are laminated on a conductive base. CONSTITUTION:This electrophotographic sensitive body is constituted by laminating the charge generating layer and the charge transfer layer on the conductive base. At least one kind of tau, tau', eta, eta' type metallic phthalocyanines are incorporated into said charge generating layer and the compd. satisfying formula I is incorporated into the charge transfer layer, by which the exposing sensitivity characteristic is enhanced and the high sensitivity to a long wavelength region of iota780nm is obtd. The stability in repetitive use and a good photomemory characteristic are obtd. as well. In formula, R1-R4; a hydrogen atom, alkyl group or alkoxy group of 1-10C which may have a substituent, aryl group of 6-12C which may have a substituent, and a residual group with which R1 and R4 or R2 and R4 form a cyclic amino group together with the nitrogen atom bonded thereto.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more specifically,
The present invention relates to an electrophotographic photoreceptor having excellent exposure sensitivity characteristics and wavelength characteristics.

(Conventional technology) Conventionally, selenium has been used as the photoreceptor for electrophotographic photoreceptors.

Inorganic photoconductors such as selenium alloys, zinc oxide, cadmium sulfide and tellurium have been used primarily. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost and are beginning to be used as light sources for electrophotography. But 3
Using semiconductor lasers that emit short-wavelength light in these devices has many problems in terms of lifespan, output, etc. Therefore, the conventionally used materials that are sensitive in the short wavelength region are unsuitable for use in semiconductor lasers, and there is a need to research materials that are highly sensitive in the long wavelength region (780 nm or more). Ta. Recently, organic materials, especially phthalocyanine, which is expected to have sensitivity in the long wavelength region, have been used.
Research into multilayer organic photoreceptors in which these materials are laminated is being actively conducted. Phthalocyanine with high sensitivity in the long wavelength region (
As a Pc)-based material, ε-type copper phthalocyanine (
ε-CuPc), X-type metal-free phthalocyanine (X R
2P c) and τ-type metal-free phthalocyanine are known, but electrophotographic photoreceptors formed in combination with conventional charge transfer agents have problems with sensitivity, stability during repeated use, photomemory properties, etc. It was at a level that could hardly be said to be sufficient for actual use.

(Problems to be Solved by the Invention) The objects of the present invention are to provide an electrophotographic photosensitive material with excellent exposure intensity characteristics, high sensitivity in the long wavelength region of 780 nm or more, stability during repeated use, and good photomemory properties. It's about getting a body.

[Structure of the invention]

(Means and effects for solving the problem) The above object is to provide at least one metal-free phthalocyanine selected from τ, τ', η and η' type metal-free phthalocyanines as a charge generating agent on a conductive support. The charge generation layer used and the charge transfer agent contain a compound represented by the general formula [I].

Alternatively, it can be achieved by an electrophotographic photoreceptor formed by stacking charge transfer layers containing both the compounds represented by the general formula (1) and the general formula [II].

General formula (1) (wherein RI, Rz, Rs and R6 are hydrogen atoms, alkyl groups or alkoxy groups which may have a substituent having 1 to 10 carbon atoms, or 6 to 12 carbon atoms) General formula (n) represents a residue that forms a cyclic amino group with the nitrogen atom to which +R1 and R1, or R1 and R4 are bonded, and is an allyl group that may have a substituent. In the formula, +RS represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, a naphthyl group, a benzyl group, and RI and R2 are
Expresses the same meaning as above. ) τ, τ', η and η' type metal-free phthalocyanine used in the present invention JP-A-57-66963.

It was manufactured by the method disclosed in Japanese Patent No. 5B-183757.

More specifically, the substituents R8 to R4 in the general formula (1) or (I[) used in the present invention include an alkyl group such as a methyl group, an ethyl group, a propyl group, or a substituted alkyl group such as a benzyl group. Examples include alkoxy groups such as methoxy, ethoxy and butoxy groups, allyl groups such as phenyl and naphthyl groups, and substituted allyl groups such as tolyl and methoxyphenyl groups.

The electrophotographic photoreceptor of the present invention preferably has an undercoat layer, a charge generation layer, and a charge transfer layer laminated in this order on a conductive substrate. A laminated one is fine.

Moreover, an overcoat layer made of resin or inorganic oxide can be provided as the uppermost layer, if necessary.

The charge generation layer may be applied without a resin, or if necessary, after dispersion coating one or more of the τ, η and η types in an appropriate resin solution.

Keep dry.

Coating is carried out using a spin coater, applicator, spray coater, bar coater, dip coke, doctor blade, roller coater, curtain coater or bead coater, and drying is carried out using a spin coater, applicator, spray coater, bar coater, dip coater, doctor blade, roller coater, curtain coater or bead coater.

Desirably, drying is carried out by heating at 40 to 200° C. for 10 minutes to 6 hours under stationary or blowing air conditions. After drying, the film is coated to a thickness of 0.01 to 5 microns, preferably O6l to 1 micron.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide variety of insulating resins.

It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably polyvinyl butyral,
Polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide resin, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, silicone Examples include insulating resins such as resin, polystyrene, polyketone resin, polyvinyl chloride, vinyl chloride copolymer, polyvinyl acecool, polyacrylonitrile, phenol resin, melamine resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is suitably 100% by weight or less, preferably 40% by weight or less. Further, these resins may be used alone or in combination of two or more.

The solvent for dissolving these resins varies depending on the type of resin, and it is preferable to select a solvent that does not affect the charge transfer layer and undercoat layer described later during coating.

Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin 5 monochlorobenzene, dichlorobenzene,
Ketones such as acetone, methyl ethyl ketone, and cyclohexanone, methanol, and ethanol.

Alcohols such as isopropanol, ethyl acetate.

Esters such as methyl cellosolve, carbon tetrachloride.

Chloroform, dichloromethane, dichloroethane.

Aliphatic halogenated hydrocarbons such as trichlorethylene, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether.

Amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and sulfoxides such as dimethylsulfoxide are used.

The charge transfer layer is formed by dissolving and dispersing a charge transfer agent alone or a binder resin in a suitable solvent. The charge transfer agent has the general formula [! ] and [■] are used.

The resin used for the charge transfer layer is silicone resin.

Ketone resin, polymethyl meccrylate, polyvinyl chloride, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral.

Insulating resins such as polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, etc.
JN-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, etc. are used.

Coating methods include spin coater and applicator.

Spray coater, bar coater, dip coke.

The coating is carried out using a doctor blade, roller coater, curtain coater, or bead coater, and the film thickness after drying is preferably 5 to 50 microns, preferably 10 to 20 microns.

The compounding ratio of the resin and the compound of general formula (1) is preferably 0.1 to 10 parts by weight of the compound of general formula (I) per 1 part by weight of resin.

Furthermore, when the compounds represented by the general formulas CI) and (II) are used together, the effect can be recognized regardless of the mixing ratio of the compounds represented by the general formulas CI) and (II), but the compound represented by the general formula (1) per part by weight of the compound of the general formula (I
0.1 to 10 parts by weight of the compound I) is desirable. The mixing ratio of the mixture of compounds of general formulas (1) and (I[) to the resin is per 1 part by weight of the resin.

Preferably, the amount of the mixture is 0.1 to 10 parts by weight.

Further, these resins may be used alone or in combination of two or more.

A photoreceptor using the compound of general formula (1) as a charge transfer agent has the advantage of high sensitivity, low photomemory property, and little deterioration due to light. Also.

Due to the high sensitivity, it is also possible to reduce the amount of charge transfer agent in the charge transfer layer, which has a great effect on the durability and environmental resistance of the photoreceptor. In addition, the compound of general formula (II) is mixed with the compound of general formula (1).

In addition to the above-mentioned effects, forming a charge transfer layer improves charging properties and prevents deterioration of characteristics at low temperatures.

It becomes a well-balanced photoreceptor.

Furthermore, the solvent used in forming the charge transport layer of the present invention includes many useful organic solvents.

Examples include aromatic hydrocarbons such as evaporate, benzene, toluene, xylene, chlorobenzene, and naphthalene. Acetone, 2
-Ketones such as butanone. Methylene chloride.

Halogenated aliphatic hydrocarbons such as ethylene chloride and chloroform. Tetrahydrofuran, 1,4-dioxane,
Examples include cyclic or linear ethers such as ethyl ether, and mixed solvents thereof.

In addition to these layers, an undercoat layer can be provided on the conductive substrate for the purpose of preventing deterioration of chargeability, improving adhesion, and the like. Polyethylene as an undercoat layer.

Polypropylene, allyl resin, meccrylic resin.

Vinyl chloride resin, vinyl acetate resin, phenolic resin.

Epoxy resin, polyester resin, alkyd resin.

Polycarbonate resin, polyurethane, salt vinyl acetate resin.

Vinylidene chloride resin, nylon 6, nylon 66°, nylon 11. Nylon 610. Copolymerized nylon.

Alcohol-soluble polyamides such as alkoxymethylated nylon, casein, polyvinyl alcohol.

Nitrocellulose, ethylene-acrylic acid copolymer,
Gelatin, polyurethane, polyvinyl butyral and metal oxides such as aluminum oxide are used. In addition, metal oxides such as zinc monoxide and titanium oxide, silicon nitride,
The conductivity of the undercoat layer can also be adjusted by incorporating conductive and dielectric particles such as silicon carbide and carbon blank into the resin.

The coating thickness is preferably 0.1 to 50 microns, preferably 0.1 to 1 micron.

The support used in the electrophotographic photoreceptor of the present invention includes:

Any material may be used as long as it has conductivity.

Any type of conductive layer conventionally used may be used. Specifically, aluminum and copper.

Metals such as stainless steel, iron, brass, tin, and nickel, as well as paper and plastic using these metals.

The film may be made conductive by performing a process such as vapor deposition or lamination on a polymer film such as polyethylene terephthalate (PET). Also.

Its shape can be sheet-like or cylinder-like.

There is no problem even if it is something else.

LEDs have also been put into practical use as digital light sources for printers.

LEDs in the visible light range are also used, but those that are generally in practical use have a wavelength of 650nm or more, and the standard is 660nm.
It has an oscillation wavelength of m. The electrophotographic photoreceptor is 6
Since it has a spectral sensitivity peak around 50 nm, it is also effective as a material for LEDs.

The material of the present invention has a spectral sensitivity peak at 800 nm or more, and is suitable not only for use as an electrophotographic photoreceptor in copying machines and printers, but also as an absorbing material for solar cells, photoelectric conversion blocking, and optical disks.

Hereinafter, one embodiment of the present invention will be specifically described.

In the examples, parts refer to parts by weight.

Example 1 Copolymerized nylon (Amiran CM-8000 manufactured by Toshi) 10
was mixed with 190 parts of ethanol in a ball mill for 3 hours, and the dissolved coating liquid was applied with a wire bar onto a sheet of polyethylene terephthalate (PET) film with aluminum vapor-deposited and dried at 100°C for 1 hour. A sheet having a subbing layer with a thickness of 0.5 microns was obtained.

Next, 1 part of τ-type metal-free phthalocyanine, 1 part of butyral resin (S-LEC BH-3: manufactured by Tanemizu Kagaku ■) and T
30 parts of HF was dispersed in a ball mill for 4 hours.

This dispersion is applied onto the previously formed undercoat layer.

After drying at 100° C. for 2 hours, a 0.3 micron charge generation layer was obtained.

Furthermore, 1 part of the following compound (a) and 1 part of polycarbonate resin (Panrai L-1250i manufactured by Teikoku Kasei) were mixed and dissolved in methylene chloride for 8 minutes. This liquid was applied onto the charge generation layer and dried at 80° C. for 1 hour to form a charge transfer layer of 15 microns to obtain an electrophotographic photoreceptor.

Compound (a) The electrophotographic photoreceptor obtained in this example was subjected to static mode 2. Corona charging is -5.2KV.

The white light half-reduction exposure sensitivity (E〃 and E'/S) was determined from the surface potential and the time at which the charge amount decreased by A and 1 μm after irradiation with 5 Lux of white light. In addition, the repetition characteristics were evaluated under the conditions of -5.2 KV and a corona linear velocity of 20 m/win.
Repeat the sequence of 3 s exposure at x 1 surface potential.

Residual potential and sensitivity deterioration were measured. Note that the residual potential is the potential (VRs) after 3 seconds of light irradiation.

For photomemory property (PM), one photoreceptor was left under 600 lux for 3 minutes, then left in a dark place for 1 minute, and the electrostatic properties were measured again under the same conditions. Therefore.

The change in the charged potential (vo) of the photoreceptor before 600 lux irradiation and after 600 lux irradiation was defined as photo memory (PM). Therefore, photo memory (P
M) is expressed by the following formula.

PM = Surface potential before exposure to strong illuminance (600 lux) - Surface potential after exposure to strong illuminance Table 1 Initial electrophotographic characteristics Table 2 Initial electrophotographic characteristics One test was carried out based on the results shown in Tables 1 and 2. The electrophotographic photoreceptor obtained in the example has excellent sensitivity and low residual potential, even after 10,000 repeated tests.

Very good results were obtained that were almost the same as the initial characteristics. Furthermore, the photomemory (PM) is small, and it is understood that the photoreceptor is stable against irradiation light.

Example 2 On a PET film coated with an undercoat layer and a charge generation layer in the same manner as in Example 1, 0.5 part of compound Ca) was added.
0.5 part of the following compound (b), polycarbonate resin (
A solution obtained by mixing and dissolving 1 part of Panrai) L-1250 (manufactured by Kijin Kasei) in 8 parts of methylene chloride was applied onto the charge generation layer and dried at 80° C. for 1 hour.

A charge transfer layer of 15 microns was formed, and an electrophotographic photoreceptor was prepared.

Compound (b) Table 3 Initial electrophotographic properties Table 4 The electrophotographic photoreceptor obtained from the initial electrophotographic properties also showed good properties.

Further, the characteristics of the electrophotographic photoreceptors obtained in Examples 1 and 2 were measured at different environmental temperatures. The results are shown in Table 5.

When the compound shown in Table 5 Example 1<a) is used alone, desensitization is greater at the measurement temperature of 10°C than at 25°C room temperature. )
It can be seen that when a mixture of the following is used, there is less desensitization and changes in characteristics due to temperature are small. Therefore, the compound (a
Although the electrophotographic photoreceptor using Compound (a) has excellent electrophotographic properties, the properties deteriorate at low temperatures.
By adding and using compound (b),
Even better characteristics were obtained. Furthermore, the moisture resistance and environmental resistance (deterioration due to Os, NOx, etc.) were also good.

Comparative Examples 1 to 2 Electrophotographic photoreceptors were prepared in the same manner as in Example 1, except that the charge transfer agent shown below was used in place of compound (a).

Tables 6 and 7 show the electrophotographic properties of the electrophotographic photoreceptor using the above charge transfer agent.

Table 6 Initial Electrophotographic Characteristics Compared to Example 1, the residual potential is higher and the sensitivity is inferior. In addition, the photomemory is large and its surface potential decreases due to light irradiation.

Table 7 Initial electrophotographic properties Using τ-type metal-free phthalocyanine as a charge generating agent, the compound (
The photoreceptors of Examples 1 and 2, which used a mixture of materials a) and (b) as a charge transfer agent, had better sensitivity than the photoreceptor of the comparative example, and had less residual potential and less photomemory. . In addition, the repeatability is stable and the repeatability is 10000.
After the test, the value was almost the same as the initial value.

Photomemory is a phenomenon in which when an electrophotographic photoreceptor is irradiated with strong light, the potential retained on the surface of the photoreceptor, which occurs during subsequent charging and exposure processes, changes significantly compared to before the light irradiation. Depending on the intensity of the light, it may be temporary or may not recover permanently. Therefore, if the photomemory property is small, the charging property will be stable even when exposed to irradiation light or natural light when handling the photoreceptor, so when actually used in copiers and printers, it will be extremely stable for electrophotography. characteristics can be obtained, and handling and maintenance as a photoreceptor are also easy. This has the advantage that a stable and high-quality image can be obtained even from a single image point of view.

〔Effect of the invention〕

According to the present invention, an electrophotographic photoreceptor has been obtained which has high sensitivity, is stable during repeated use, has good photomemory properties, and provides stable, high-quality images.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor formed by laminating a charge generation layer and a charge transfer layer on a conductive support, the charge generation layer has τ
, contains at least one metal-free phthalocyanine selected from τ', η and η' type metal-free phthalocyanines,
An electrophotographic photoreceptor characterized in that the charge transfer layer contains a compound represented by the following general formula [I]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. or an alkoxy group, or a carbon number of 6 to
It is an allyl group which may have a substituent of 12, and represents a residue that forms a cyclic amino group together with the nitrogen atom to which R_1 and R_2 or R_3 and R_4 are bonded. ) 2. In an electrophotographic photoreceptor formed by laminating a charge generation layer and a charge transfer layer on a conductive support, the charge generation layer has a τ
, contains at least one metal-free phthalocyanine selected from τ', η and η' type metal-free phthalocyanines,
An electrophotographic photoreceptor characterized in that the charge transfer layer contains both a compound represented by the following general formula [I] and a compound represented by the following general formula [II]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. or an alkoxy group, or a carbon number of 6 to
It is an allyl group which may have a substituent of 12, and represents a residue that forms a cyclic amino group together with the nitrogen atom to which R_1 and R_2 or R_3 and R_4 are bonded. ) General formula [II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_5 represents an alkyl group having 1 to 6 carbon atoms, phenyl group, naphthyl group, benzyl group,
2 represents the same meaning as above. )