JPH05232719A - Electrophotographic sensitive member - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive member, i.e., photoreceptor, which exhibits a high sensitivity and excellent repetitive characteristics when it is used repeatedly in the electrophotographic processes. CONSTITUTION:An electrophotographic sensitive member is formed by providing an electric charge generating layer and an electric charge moving layer on an electroconductive support, wherein the feature is such that phthalocyanine compound as given by a formula as shown is included in the electric charge generating layer in the extent 0.005 to 1 parts by weight to 100 parts by weight electric charge generating substance. In formula, R represents halogen atom, cyano radical, or nitro radical while M a hydrogen atom or a metal atom, and (n) is the valency of the M atom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member having high sensitivity and excellent repeatability.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member,
Those having a photosensitive layer containing an inorganic photoconductor as a main component such as selenium, cadmium sulfide, zinc oxide, and silicon have been widely known. However, these are not always satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. Further, selenium and cadmium sulfide are particularly toxic and therefore, they are limited in production and handling.

On the other hand, an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductive compound as a main component is relatively easy to manufacture, inexpensive, easy to handle, and generally selenium photosensitive. It has many advantages such as superior thermal stability as compared with the body, and has received much attention in recent years.

As such an organic photoconductive compound,
Poly-N-vinylcarbazole is well known, and an electrophotographic photosensitive material having a photosensitive layer containing as a main component a charge transfer complex formed from this and a Lewis acid such as 2,4,7-trinitro-9-fluorenone. The body is Japanese public Sho 50-10496
It is described in Japanese Patent Publication No. However, this photoreceptor was not always satisfactory in sensitivity, film-forming property and durability.

On the other hand, an electrophotographic photosensitive material containing a low molecular weight organic photoconductor in which a charge transfer agent typified by triphenylamines, stilbenes and hydrazones and a charge generating agent such as phthalocyanine and an azo compound are combined. The body is proposed. By combining these with an appropriate binder, and further combining a compound having a high charge generation ability and a compound having a high charge transfer ability, for example, as a laminated type photoreceptor, a compound having a sensitivity close to that of an inorganic photoreceptor such as selenium has appeared. There is. As a result, in the fields of copying machines, printers, etc., photoconductors containing such organic photoconductive compounds as a main component have made great progress.

On the other hand, when such an organic photoreceptor is subjected to complicated processes such as charging, exposure and charge elimination in a copying machine,
The compound not only plays a role of generating and transferring an electric charge, but also receives a stimulus such as ozone and light in a high electric field. Therefore, as the process is repeated, many problems remain in use, such as a decrease in initial potential after charging and an increase in residual potential after static elimination.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member which has a remarkably small variation in charging potential and residual potential upon repeated use in an electrophotographic process and which has high sensitivity.

[0008]

As a result of various studies to achieve the above object, the present inventors have found that in a laminated electrophotographic photoreceptor having a charge generation layer and a charge transfer layer, the charge generation layer is It was found that it is effective to add the phthalocyanine compound represented by the general formula 1 to the charge generating substance in a very small amount ratio, and the present invention has been completed.

The present invention is an electrophotographic photosensitive member comprising a charge generating layer and a charge transfer layer provided on a conductive support, wherein the phthalocyanine compound represented by the general formula 1 is added to 100 parts by weight of the charge generating substance. On the other hand, the electrophotographic photosensitive member is characterized in that it is contained in the charge generation layer in an amount of 0.005 to 1 part by weight.

In Chemical Formula 1, R represents a halogen atom, a cyano group or a nitro group, M represents a hydrogen atom or a metal atom, and n represents the valence of the M atom.

With respect to the reason why the fluctuations of the charging potential and the residual potential become extremely small when the photoconductor in which the phthalocyanine compound of Chemical formula 1 in the present invention is added to the charge generation layer is repeatedly used in the electrophotographic process. Is not yet fully understood, it is considered that the outermost substituent R of the phthalocyanine compound has a great effect. R needs to be a substituent having a high electron withdrawing property, and it is considered that this electron withdrawing group controls the electronic state in the charge generation layer. Therefore, R is preferably a chloro group, a cyano group, a nitro group or the like, more preferably a cyano group or a nitro group. As M,
2 hydrogen atoms, or Ti, V, Cr, Fe, Cu,
It is selected from Zn, Ga, Al, Pb, Ge, Sn, In, Co and the like, and when M is a metal atom, n is determined by the kind of the selected atom. n usually has a value of 2, 3 or 4. These phthalocyanine compounds can be easily synthesized by a method known to those skilled in the art.

There is an appropriate range for the amount of the phthalocyanine compound added to the charge generation layer, and if the amount added exceeds the range, the dark conductivity of the photoreceptor becomes large and the chargeability becomes low. Moreover, the effect becomes small if the addition amount is small. The phthalocyanine compound is contained in an amount of 0.005 to 1 part by weight based on 100 parts by weight of the charge generating substance. It is preferably contained in the range of 0.005 to 0.1 parts by weight.

Hereinafter, each component of the present invention will be described in detail. First, as the electroconductive support on which the photosensitive layer of the photoconductor is formed, any of those known in electrophotographic photoconductors can be used. Specifically, for example, gold, silver,
Examples thereof include platinum, titanium, aluminum, copper, zinc, iron, drums, sheets, belts made of metal oxides or the like subjected to conductive treatment, laminates of these thin films, vapor depositions and the like.

Further, metal powder, metal oxide, carbon black, carbon fiber, copper iodide, charge transfer complex, inorganic salt,
Drums, sheets, belts, etc. made of plastic, ceramics, paper, etc., which have been coated with a conductive substance such as an ion-conductive polymer electrolyte together with a suitable binder and embedded in a polymer matrix and have been subjected to a conductivity treatment, such as Drums, sheets, belts and the like of plastics, ceramics, papers, etc., which are made conductive by containing such a conductive substance can be mentioned.

The photosensitive layer is of a laminated type in which the charge generating substance and the charge transfer substance are separated into separate layers and sealed in a binder. A blocking layer may be provided between the photosensitive layer and the conductive support in order to control the injection of charges from the photosensitive layer to the conductive support, and the surface of the photosensitive layer improves the durability of the photoreceptor. Therefore, a surface layer may be provided.

Examples of the charge generating substance used include azo pigments represented by monoazo pigments, polyazo pigments, metal complex salt azo pigments, pyrazolone azo pigments, stilbene pigments and thiazole azo pigments, perylene anhydrides and perylene imides. Representative perylene pigments, anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, violanthrone derivatives, and anthraquinone or polycyclic quinone pigments such as isoviolanthrone derivatives, metal phthalocyanines, metal salts. Phthalocyanine pigments such as phthalocyanine, metal-free phthalocyanine, and metal-free naphthalocyanine, pigments such as porphyrin derivatives, and triphenylmethane dyes represented by methyl violet, quinone dyes such as quinizarin. Pyrylium salt, thiapyrylium salt,
Examples include dyes such as benzopyrium salts.

Of these, bisazo pigments, trisazo pigments, and phthalocyanine pigments having high carrier generation efficiency are preferable because they give high sensitivity and provide an excellent photoconductor. For example, in the case of a bisazo pigment, JP-A Nos. 62-286058, 63-32557, 63-243948, 64-21453, 64-21455 and 64-21455. -94350 gazette, the same 1-20026.
The compounds described in JP-A No. 7 and JP-A No. 1-220757 can be used.

In the function-separated laminated type photoreceptor, at least the charge-generating substance and the binder resin are mixed to form the charge-generating layer. As the binder resin, styrene, vinyl acetate, acrylic acid ester, a polymer or copolymer of a vinyl compound such as methacrylic acid ester, silicon resin, phenoxy resin, butyral resin, formal resin, phenolic resin, polycarbonate, polyarylate, polyamide , Thermosetting resin such as polyimide, epoxy resin, urethane resin, and photocurable resin. The binder is used in an amount of 1 to 1000 parts by weight, preferably 1 to 400 parts by weight, based on 100 parts by weight of the charge generating material. The thickness of the charge generation layer is 0.1 to 20.
μm is preferred.

The charge transfer material used in the charge transfer layer includes a hole transfer material and an electron transfer material. Examples of the former include, for example, oxadiazoles disclosed in JP-B-34-5466, triphenylmethanes disclosed in JP-B-45-555, and JP-B-52-4188.
Disclosed in Japanese Patent Publication No. 55-42
Hydrazones disclosed in JP-A-380, JP-A-56
Examples include oxadiazoles disclosed in JP-A-123544, triarylamines disclosed in JP-B-58-32372, and stilbenes disclosed in JP-A-58-198043. You can On the other hand, examples of the electron transport material include chloranil, tetracyanoethylene, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitroxanthone,
1,3,7-trinitrodibenzothiophene and the like. These charge transfer substances can be used alone or in combination of two or more.

Among these charge transfer substances, hydrazone compounds and stilbene compounds are preferable because they have high charge (hole) mobility and provide an excellent photoconductor. For example, in the case of a hydrazone compound, the above-mentioned Japanese Patent Publication Sho 55
No. 42380, and Japanese Patent Laid-Open No. 1-100
No. 555, No. 2-10367, and No. 2-511.
No. 63, No. 2-96767, No. 2-1832.
No. 60, No. 2-184856, No. 2-184.
No. 858, No. 2-184859, No. 2-22
The hydrazone compounds described in Japanese Patent No. 6160 can be used.

As the binder resin used in the charge transfer layer, polystyrene, acrylic resin typified by polymethylmethacrylate, polycarbonate having bisphenol A or Z skeleton, polyarylate, polyphenylene ether, polyether sulfone, polyamide, polyimide, A polyester resin or the like can be used.

In the charge transfer layer, the binder is used in the range of 10 to 400 parts by weight based on 100 parts by weight of the charge transfer material. The thickness of the charge transfer layer is preferably 5 to 100 μm.

The electrophotographic photoreceptor of the present invention may contain an antioxidant such as 2,6-ditertiarybutylparacresol and DL-α-tocopherol in order to prevent deterioration of the constituent organic compounds due to oxidation. .. Further, a well-known plasticizer may be used in order to improve film-forming property, flexibility and mechanical strength.

Further, in the case of the electrophotographic photoreceptor of the present invention, a pigment is dispersed in a solvent, and a dye, a binder and a charge transfer substance are dissolved before use. Solvents used are halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, trichloroethane and trichlorethylene, aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as dioxane, tetrahydrofuran and dimethoxyethane, methyl cellosolve and dimethyl cellosolve. ,
A solvent such as a cellosolve-based solvent such as methyl cellosolve acetate or a mixed solvent of two or more kinds thereof or, if necessary, a solvent such as alcohols, acetonitrile, N, N-dimethylformamide, and methyl ethyl ketone can be further added and used. Further, when coating on a drum, a dipping coating method or the like is used.

[0025]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 100 parts by weight of the bisazo pigment of formula 2, 0.05 parts by weight of octacyanophthalocyanine (structural formula 3), and 100 parts by weight of phenoxy resin (PKHJ manufactured by Union Carbite) were added to 10000 parts by weight of dimethoxyethane. Mix and disperse with glass beads in paint conditioner for 2 hours. The pigment dispersion thus obtained was applied onto an aluminum vapor-deposited film (Metal Me manufactured by Toray Industries, Inc.) with an applicator and dried at 80 ° C. for 15 minutes to form a charge generation layer having a thickness of about 0.2 μm.

[0027]

[Chemical 2]

[0028]

[Chemical 3]

Next, 10 parts by weight of the hydrazone compound of Chemical formula 4 and polyarylate resin (U-polymer manufactured by Unitika) 1
0 part by weight was dissolved in 200 parts by weight of dichloromethane, and this solution was applied onto the film of the above charge generating substance by an applicator and dried at 80 ° C. for 60 minutes to form a charge transfer layer having a dry film thickness of 20 μm. ..

[0030]

[Chemical 4]

The laminated electrophotographic photoreceptor thus prepared was stored at room temperature in a dark place for one day and then subjected to electrophotographic characteristic evaluation by an electrostatic recording test apparatus (SP-428 manufactured by Kawaguchi Denki Co., Ltd.). The measurement conditions are as follows: corona applied voltage: -6 kV, static mode No. 3, illumination light (white light) illuminance: 2l
It was ux. As a result, the charging voltage was −695 V and the half-exposure amount was 1.8 lux · second, which was a very high value.

Next, this photosensitive member was attached to an aluminum drum base tube, and the repeated characteristics of charging exposure were evaluated by a drum photosensitive member evaluation device (Cynthia 90 manufactured by Gentec Co., Ltd.). The measurement is a corona applied voltage: -6.5k
V, the process speed was 160 mm / sec, and the charging and photo-erasing were repeated 5000 times in the TCCD2 mode. Photostatic elimination was performed using a tungsten lamp array. Table 1 shows the measurement results of the surface potential after charging, that is, the charging potential, and the surface potential after photo-eliminating, that is, the residual potential. It can be seen that the changes in charging potential and residual potential are extremely small.

[0033]

[Table 1]

Examples 2 to 5 and Comparative Examples 1 to 3 Laminated photoreceptors were prepared in the same manner as in Example 1 except that the addition amount of octacyanophthalocyanine was changed as shown in Table 2, and the same measurement as in Example 1 was carried out. Under the conditions, the half-exposure amount of the photoconductor and the repeating characteristics were tested. The results are shown in Table 3.

[0035]

[Table 2]

[0036]

[Table 3]

From these results, it can be seen that the photoconductors of the present invention shown in the examples are superior to the comparative examples in electrophotographic characteristics, particularly in stability of charging potential due to repeated use.
In the case of the second embodiment, the initial value of the charging potential is slightly lower than that of the other embodiments, but it is in a practically acceptable range. Further, as shown in Comparative Example 3, when the addition amount of the phthalocyanine compound is excessively increased, the initial value of the charging potential becomes low, which adversely affects.

Examples 6 to 8 Laminated photoreceptors were prepared in the same manner as in Example 1 except that the azo pigments (Chemical Formulas 5 and 7) and the metal-free phthalocyanine pigment (Chemical Formula 6) shown in Table 3 were used as the charge generating substances. Then, under the same measurement conditions as in Example 1, the half-exposure amount of the photoconductor and the repeating property test were conducted. The results are shown in Table 4.

Comparative Examples 4 to 6 Comparative Example 1 (conditions in which octacyanophthalocyanine was not added) except that the azo pigments (Chemical Formulas 5 and 7) and the metal-free phthalocyanine pigment (Chemical Formula 6) shown in Table 3 were used as the charge generating substances. A laminated photoconductor was prepared in the same manner as in Example 1), and the half-exposure amount of the photoconductor and the repeating characteristics were tested under the same measurement conditions as in Example 1. The results are shown in Table 4.

[0040]

[Table 4]

[0041]

[Chemical 5]

[0042]

[Chemical 6]

[0043]

[Chemical 7]

[0044]

[Table 5]

Example 9 As an electric charge generating substance, 100 parts by weight of the azo pigment of Chemical formula 7, 0.03 parts by weight of tetranitrocopper phthalocyanine (structural formula 8), and 100 parts by weight of butyral resin (# 3000-K manufactured by Electrochemical Co., Ltd.) were used. Was mixed with 10000 parts by weight of tetrahydrofuran and dispersed with glass beads for 2 hours by a paint conditioner. The pigment dispersion liquid thus obtained was applied to an aluminum thin plate (JIS
# 1050) and was dried at 80 ° C. for 15 minutes to form a charge generation layer having a film thickness of about 0.2 μm.

Next, the stilbene compound represented by the chemical formula 9
0 parts by weight, polycarbonate resin (Z-Made by Mitsubishi Gas Chemical Co., Inc.
200) 10 parts by weight is dissolved in 160 parts by weight of dichloroethane, and this solution is applied onto the film of the carrier generating substance by an applicator and dried at 80 degrees for 60 minutes to obtain a dry transfer film thickness of 20μ. Layers were formed. The photoreceptor thus produced was subjected to the same repeated test as in Example 1. The results are shown in Table 5.

Example 10 A laminated photoreceptor was prepared in the same manner as in Example 9 except that the hydrazone compound represented by Chemical formula 10 was used in place of the stilbene compound, and the half of the photoreceptor was obtained under the same measurement conditions as in Example 1. The exposure amount and the repeating characteristic were tested. The results are shown in Table 5.

[0048]

[Chemical 8]

[0049]

[Chemical 9]

[0050]

[Chemical 10]

[0051]

[Table 6]

[0052]

As is apparent from the above, according to the present invention, it is possible to provide an electrophotographic photoreceptor having high sensitivity and excellent repetitive characteristics.

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a charge generation layer and a charge transfer layer provided on the conductive support, wherein the phthalocyanine compound represented by the following general formula 1 is 0.1. An electrophotographic photosensitive member characterized by being contained in the charge generation layer in an amount of 005 parts by weight to 1 part by weight. [Chemical 1] (In Chemical Formula 1, R represents a halogen atom, a cyano group or a nitro group, M represents a hydrogen atom or a metal atom, and n represents the valence of the M atom.)