JPH07244389A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To stabilize characteristics over a long period of time by incorporating a specified aniline compd. or phenylenediamine compd. as an antioxidant into an electric charge transferring layer. CONSTITUTION:A photosensitive layer 5 consisting of an electric charge generating layer 2 and an electric charge transferring layer 3 is formed on an electric conductive substrate 1 and an aniline compd. represented by formula I or a phenylenediamine compd. represented by formula II is incorporated as an antioxidant into the electric charge transferring layer 3 to obtain the objective photoreceptor. In the formula I each of R1 and R2 is optionally substd. aryl, alkyl or allylene and R3 is H, halogen, hydroxyl, amino or alkyl. In the formula II, each of R4-R6 is optionally substd. aryl, alkyl of allylene and each of R7 and R8 is H, halogen, hydroxyl, amino or alkyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive layer of an electrophotographic photoreceptor, and more particularly, an antioxidant used in a charge transport layer,
Charge transport materials and binders.

[0002]

2. Description of the Related Art Electrophotographic photoreceptor (hereinafter referred to as photoreceptor)
Has a structure in which a photoconductive layer having photoconductivity is laminated on a conductive substrate. An organic photoconductor containing an organic compound as a functional component responsible for charge generation and transport, particularly a charge generation layer
Laminated organic photoconductors that have functional layers such as charge transport layers are easy to design functionally, have high productivity by coating method, and are excellent in safety. Applications have been actively studied in recent years. Particularly, in the case of using a distyryl compound having a triphenylamine skeleton as a charge transporting substance and using polycarbonate as a binder for a hole transporting layer, a photoreceptor having excellent responsiveness can be expected due to its high hole mobility.

However, when this laminated organic photoreceptor is used for a long time under practical conditions, problems such as a decrease in charging potential, an increase in residual potential, and a decrease in sensitivity occur. Some external factors can be cited as the causes of these. That is, it is exposed to ozone generated in the discharge / charging process and exposed to strong external light during maintenance. The influence of these external factors on the above-mentioned various characteristics can be confirmed by an experimental method such as leaving the photoconductor in an ozone atmosphere or irradiating a predetermined amount of light.

In order to solve the above problems, various attempts have been made to incorporate additives known as antioxidants and ultraviolet absorbers into the photoreceptor. Among them, it has been reported that an antioxidant having a so-called phenol structure is effective. For example, there are JP-A-62-105151, JP-A-63-1836, and the like, but the current situation is that a technology capable of satisfying all required performances has not yet been established.

[0005]

As described above, the organic material has many advantages that the inorganic material does not have, but at the same time, it has not been possible to sufficiently satisfy all the characteristics required for the organic photoreceptor. The current situation is that, particularly when used for a long time under practical conditions, there are problems such as a decrease in charging potential, an increase in residual potential, and a decrease in sensitivity.

The present invention has been made in view of the above problems, and by using a novel organic material which has never been used as an antioxidant, a charge transporting material or a binder in a photosensitive layer, An object of the present invention is to provide a photoconductor for electrophotography, which realizes the stabilization of the characteristics.

[0007]

According to the present invention, the above-mentioned object is to provide a photosensitive layer formed on a conductive substrate at least comprising a charge generation layer and a charge transport layer, and the charge transport layer is represented by the following general formula: An aniline compound represented by (I) or at least one phenylene diamine compound represented by the following general formula (II) is contained as an antioxidant.

The charge-transporting layer contains at least one distyryl compound represented by the following general formula (III) and at least one diamine compound represented by the following general formula (IV) as a charge-transporting substance. This is achieved by the charge transport layer containing a bisphenol A-biphenyl copolymerized polycarbonate represented by the following structural formula (V) as a binder.

[0009]

[Chemical 6]

[Wherein R ₁ and R ₂ represent a substituted or unsubstituted aryl group, an alkyl group or an arylene group, and R ₃ represents a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or an alkyl group. ]

[0011]

[Chemical 7]

[Wherein R ₄ , R ₅ and R ₆ represent a substituted or unsubstituted aryl group, an alkyl group or an arylene group,
R ₇ and R ₈ represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or an alkyl group. ]

[0013]

[Chemical 8]

[Wherein R ₉ , R ₁₀ , R ₁₁ and R ₁₂ represent a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl or aryl group, and R ₁₃ and R ₁₄ represent a hydrogen atom and a halogen. Represents an atom, an alkyl group, and an alkoxy group. ]

[0015]

[Chemical 9]

[Wherein R ₁₅ and R ₁₆ represent a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl group or an aryl group, and R ₁₇ represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. . ]

[0017]

[Chemical 10]

[0018]

The inventors of the present invention conducted extensive experiments on various organic materials in order to achieve the above-mentioned object, and as a result of carrying out a number of experiments on these compounds, the technical elucidation thereof has not been sufficiently conducted. Even if the photoreceptor is left in an ozone atmosphere or given a history of strong light irradiation, the potential characteristics or the sensitivity characteristics do not change, and the potential characteristics or the sensitivity characteristics remain unchanged even after long-term use by an actual electrophotographic apparatus. It was confirmed that there was no change with time. That is, it has been found that the organic material forming the photosensitive layer has a function of preventing oxidative deterioration due to ozone generated in the charging process or photodegradation due to exposure to strong external light during maintenance. .

Further, the technical knowledge first revealed in the present invention is that an aniline antioxidant represented by the general formula (I) or a phenylene diamine antioxidant represented by the general formula (II) is charged. The fact is that the addition to the transport layer can prevent the above-mentioned oxidative deterioration and photodegradation or significantly delay the progress thereof. In particular, by adding this antioxidant to a mixture of a distyryl compound having a triphenylamine skeleton and an amine compound or a phenylenediamine compound as a charge transport material, excellent stabilization of the photoreceptor characteristics is realized. Is to do. Further, they have found that the stability of the repeated charging potential is dramatically improved when bisphenol A-biphenyl copolymerized polycarbonate is used as the resin binder.

[0020]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a negatively charged laminated type photoreceptor, which comprises a conductive substrate 1, a charge generation layer 2 and a charge transport layer 3.
FIG. 2 shows a positive charging laminated type photoreceptor, which is composed of a conductive substrate 1, a charge transport layer 3, a charge generation layer 2 and a protective layer 4. FIG. 3 shows a positively charged single layer type photoreceptor, which is composed of a conductive substrate 1 and a photosensitive layer 5.

The case of application to a negatively charged laminated type photoreceptor will be described below. However, this embodiment does not limit the scope of the claims of the present invention. As the conductive substrate 1, a conductive substrate such as an aluminum cylinder or an aluminum vapor-deposited film may be used alone, or the surface of the conductive substrate may be anodized, or the surface of the conductive substrate may be modified with a resin film. In this embodiment, as the conductive substrate 1, a cylindrical substrate made of aluminum having a thickness of 1 mm, a length of 310 mm and an outer diameter of 60 mm was washed and dried. Materials for the polymer dispersion film used for surface modification include casein, polyvinyl alcohol, nylon, polyamide,
Insulating polymers such as melanin and cellulose, conductive polymers such as polythiophene, polypyrrole, and polyaniline, or those polymers containing metal oxide powders and low-molecular compounds are used.

The charge generating layer 2 is composed of a charge generating agent and a resin binder. As the charge generating agent, various phthalocyanine compounds, azo compounds, polycyclic quinone compounds, squarylium compounds and their derivatives can be used. As the resin binder of the charge generation layer 2, polycarbonate, polyester, polyamide, polyurethane,
Epoxy polyvinyl butyral, polyvinyl acetal, phenoxy resin, silicone resin, acrylic resin,
A vinyl chloride resin, a vinylidene chloride resin, a vinyl acetate resin, a homer resin, a cellulose resin, or a copolymer thereof, and a halogen compound or a cyanoethyl compound are used.

The charge transport layer 3 is composed of a charge transport agent and a resin binder. As the charge transfer agent, the distyryl compound represented by the general formula (III) or the diamine compound represented by the formula (IV) is used alone or in combination as the organic charge transfer agent. As the resin binder of the charge transport layer 3, polycarbonate, polystyrene, polyphenylene ether, acrylic resin or the like can be used.

As the antioxidant to be added to the charge transport material coating solution, the aniline antioxidant represented by the general formula (I) and the phenylenediamine antioxidant represented by the general formula (II) are used. Specific examples of the compound represented by the general formula (I) are as follows.

[0025]

[Chemical 11]

Specific examples of the compound represented by the general formula (II) are as follows.

[0027]

[Chemical 12]

Specific examples of the compound represented by the general formula (III) are as follows.

[0029]

[Chemical 13]

[0030]

[Chemical 14]

[0031]

[Chemical 15]

[0032]

[Chemical 16]

[0033]

[Chemical 17]

[0034]

[Chemical 18]

Specific examples of the compound represented by the general formula (IV) are as follows.

[0036]

[Chemical 19]

Specific examples of the bisazo compound used in the charge generation layer of this example are as follows.

[0038]

[Chemical 20]

[0039]

[Chemical 21]

[0040]

[Chemical formula 22]

[0041]

[Chemical formula 23]

[0042]

[Chemical formula 24]

[0043]

[Chemical 25]

[0044]

[Chemical formula 26]

[0045]

[Chemical 27]

[Example 1] 4 parts by weight of a polyamide having a number average molecular weight of 100,000 (trade name: T171, manufactured by Daicel-Huls) and 1 part by weight of a styrene-maleic acid resin (trade name: Suprapearl AP, manufactured by BASF Japan Ltd.) Was dissolved in a mixed solvent of 200 parts by weight of methanol and 100 parts by weight of 1-butanol to prepare a resin film 0.1 μm on the conductive substrate 1 by a dipping method using a resin film coating solution prepared to form a support. It was made.

As the charge generating agent, the compound No. (VI-
1 part by weight of the bisazo compound shown in 27) and 1 part by weight of diallyl phthalate resin (trade name: DAP K, manufactured by Osaka Soda) as a binder resin are mixed with 150 parts by weight of methyl ethyl ketone, and the mixture is kneaded with a mixer for 3 hours to obtain a coating solution. Was adjusted and coated on the support by a dipping method, and the charge generation layer 2 was formed so that the film thickness after drying was 1 μm.

On the charge generating layer 2 thus obtained, the compound No. 650 parts by weight of the compound shown in (III-7), the compound No. (IV-1)
100 parts by weight of the compound shown in FIG. (IV-
250 parts by weight of the compound shown in 2), 1000 parts by weight of the bisphenol A-biphenyl copolymerized polycarbonate (trade name: BP-Pc, manufactured by Idemitsu Kosan) shown in the structural formula (V), and the compound No. 3 as an antioxidant. 15 parts by weight of the compound shown in (I-1) is dissolved in 700 parts by weight of dichloromethane, a charge transport layer coating solution is prepared and applied by a dipping method, and a charge transport layer is formed so that the film thickness after drying is 15 μm. Three
To form a photoconductor. [Example 2] The charge transporting material of Example 1 was replaced with compound No.
(III-7), Compound No. A photoconductor was produced in the same manner as in Example 1 except that (III-13) was used. [Example 3] The charge transporting material of Example 1 was compound No.
(III-7), Compound No. A photoconductor was produced in the same manner as in Example 1 except that (III-22) was used. [Example 4] The charge transport material of Example 1 was used as compound No.
(III-7), Compound No. A photoconductor was prepared in the same manner as in Example 1 except that (III-26) was used. [Example 5] The antioxidant of Example 1 was used as the compound No. (I
-1) instead of Compound No. A photoconductor was produced in the same manner as in Example 1 except that (II-1) was used. [Example 6] The antioxidant of Example 2 was compounded with compound No. (I
-1) instead of Compound No. A photoconductor was produced in the same manner as in Example 1 except that (II-1) was used. [Example 7] Bisphenol A-biphenyl copolymerized polycarbonate (trade name: BP-Pc, manufactured by Idemitsu Kosan Co., Ltd.) as a binder in the charge transport layer coating solution was replaced with 1000 parts by weight of bisphenol Z polycarbonate (trade name: P).
A photoconductor was prepared in the same manner as in Example 1 except that 1000 parts by weight of CZ300, manufactured by Mitsubishi Gas Chemical Co., Inc. was added. [Example 8] Bisphenol A-biphenyl copolymerized polycarbonate (trade name: BP-Pc, manufactured by Idemitsu Kosan Co., Ltd.) was replaced by 1000 parts by weight as a binder in the charge transport layer coating solution, and bisphenol A polycarbonate (trade name: PARNLIGHT L-). A photoconductor was prepared in the same manner as in Example 1 except that 1000 parts by weight of 1225, manufactured by Teijin Kasei) was added. [Comparative Example 1] Compound No. in the charge transport layer coating solution. (I-
A photoconductor was prepared in the same manner as in Example 1 except that the compound shown in 1) was not added. [Comparative Example 2] Compound No. in the charge transport layer coating solution. (I-
A photoconductor was prepared in the same manner as in Example 2 except that the compound shown in 1) was not added. [Comparative Example 3] Compound No. in the charge transport layer coating solution. (I-
A photoreceptor was prepared in the same manner as in Example 1 except that 40 parts by weight of a hindered phenol compound represented by the following structural formula (VII) was added instead of the compound represented by 1). [Comparative Example 4] Compound No. 4 in the charge transport layer coating solution. (I-
A photoreceptor was prepared in the same manner as in Example 2 except that 40 parts by weight of the hindered phenol compound represented by the following structural formula (VII) was added instead of the compound represented by 1). [Comparative Example 5] Compound No. 5 in the charge transport layer coating solution. (I-
A photoconductor was prepared in the same manner as in Example 7 except that the compound shown in 1) was not added. [Comparative Example 6] Compound No. 6 in the charge transport layer coating solution. (I-
A photoconductor was prepared in the same manner as in Example 8 except that the compound shown in 1) was not added.

[0049]

[Chemical 28]

The electrophotographic characteristics of the photoreceptor thus obtained were evaluated. For the purpose of evaluating potential fluctuations during continuous use, various photoconductors are installed in a copying machine or laser printer with fixed outputs of the charging mechanism, exposure mechanism, and static elimination mechanism, and in an atmosphere of normal temperature and normal humidity (20 ° C, 60RH). And then A
A running test of three sheets of 50,000 sheets was performed, and after measuring the white paper potential (Vw) and the black paper potential (Vb) at the start of running, the potential change amounts (ΔVw, ΔVb) at the end of running were measured.

For the purpose of evaluating ozone resistance, each photoreceptor was exposed to an environment of ozone concentration of 100 ppm for 4 hours, and the half-exposure amount before and after the exposure was measured and compared. Further, 1000 (lx) of light was applied to each photoconductor for the purpose of evaluating the strong light fatigue resistance.
After irradiation for a certain time, after measuring the initial charging potential (Vs) before irradiation under a constant charging condition, the charging potential change amount (ΔV
s) was measured. The results are shown in Table 1.

[0052]

[Table 1] As is clear from the above results, the compound No. (I
A photoreceptor containing no aniline compound shown in -1) or a phenylenediamine compound shown in (II-1) has significantly deteriorated photoreceptor characteristics due to ozone exposure or strong light irradiation, and running in an actual machine. The potential fluctuation due to the test deviates from the practical range. Further, as is clear from the results of Examples 1 to 8 and Comparative Examples 3 to 4, the aniline-based compound or the phenylenediamine-based compound was compared with the hindered phenol compound, and as a result, the sensitivity and the stability of charging ability were excellent. showed that. Example 1
From the results of 8 to 8, it is confirmed that the aniline-based compound or the phenylenediamine-based compound according to the present invention can exert the results in the organic photoreceptor having a wide range of structures and material compositions. Further, as can be seen from the results of Example 1 and Examples 7 to 8, when bisphenol A-biphenyl copolymerized polycarbonate was used as the resin binder, excellent stability was exhibited.

[0053]

According to the present invention, at least one of the aniline compounds represented by the general formula (I) or the phenylenediamine compounds represented by the formula (II) is used as a charge transport layer formed on a conductive substrate. Included as an antioxidant,
At least one kind of the distyryl compound represented by the general formula (III) and at least one kind of the diamine compound represented by the following general formula (IV) are contained as a charge transport material, and further represented by the structural formula (V). By including bisphenol A-biphenyl copolymerized polycarbonate as a binder, the effects as described in the examples are obtained, and there is no characteristic change under ozone atmosphere or strong light irradiation, and characteristic stability in long-term continuous use. It is possible to produce an electrophotographic photoreceptor having excellent properties.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view of a negatively charged laminated electrophotographic photoconductor according to the present invention.

FIG. 2 is a structural sectional view of a positively charged laminated electrophotographic photoconductor according to the present invention.

FIG. 3 is a structural sectional view of a positively charged single-layer type electrophotographic photoreceptor according to the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Charge Generation Layer 3 Charge Transport Layer 4 Protective Layer 5 Photosensitive Layer

Claims (3)

[Claims] 1. A photosensitive layer formed on a conductive substrate comprises at least a charge generation layer and a charge transport layer, and the charge transport layer is an aniline compound represented by the following general formula (I) or the following general formula (I): An electrophotographic photoreceptor comprising at least one kind of phenylene diamine compound represented by II) as an antioxidant. 2. The photoreceptor according to claim 1, wherein the charge transport layer comprises at least one distyryl compound represented by the following general formula (III) and at least one diamine compound represented by the following general formula (IV). An electrophotographic photoreceptor comprising a seed as a charge transport material. 3. The photoconductor according to claim 1, wherein:
An electrophotographic photoreceptor, wherein the charge transport layer contains a bisphenol A-biphenyl copolymerized polycarbonate represented by the following structural formula (V) as a binder. [Chemical 1] [Wherein R ₁ and R ₂ represent a substituted or unsubstituted aryl group, an alkyl group or an arylene group, and R ₃ represents a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or an alkyl group. ] [Chemical 2] [Wherein R ₄ , R ₅ and R ₆ represent a substituted or unsubstituted aryl group, an alkyl group or an arylene group, and R ₇ and R ₈ represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or an alkyl group. ] [Chemical 3] [Wherein R ₉ , R ₁₀ , R ₁₁ and R ₁₂ represent a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl group or an aryl group, and R ₁₃ and R ₁₄ represent a hydrogen atom, a halogen atom and an alkyl group. Represents a group and an alkoxy group. ] [Chemical 4] [Wherein R ₁₅ and R ₁₆ represent a hydrogen atom, a halogen atom, an alkoxy group or an optionally substituted alkyl group or an aryl group, and R ₁₇ represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. ] [Chemical 5]