JP3237428B2 - Electrophotographic photoreceptor - Google Patents

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 comprising a photosensitive layer containing an organic material and used in an electrophotographic printer, a copying machine or the like.

[0002]

2. Description of the Related Art A photoreceptor for electrophotography employs a structure in which a photoconductive photosensitive layer is laminated on a conductive substrate. Organic photoreceptors for electrophotography containing an organic compound as a functional component responsible for charge generation and transport, especially for multi-layer electrophotography with a high material selectivity and stacking functional layers such as a charge generation layer and a charge transport layer In recent years, photoreceptors have been actively studied for application to various printers including copiers because of their advantages such as easy functional design, high productivity by coating method, and excellent safety.

In recent years, in particular, a photoreceptor using an organic material, which has advantages such as flexibility, thermal stability, and film forming property, has been put to practical use. Further, a novel azo compound as a charge generating substance, a novel stilbene derivative as a charge transporting substance, and the like have been developed to increase the sensitivity and are used in a copying machine having a high copying speed. However, when the 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 of these causes are external factors. That is, being exposed to ozone generated in the discharge charging process,
And it is 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 photosensitive member in an ozone atmosphere or irradiating a predetermined amount of light.

[0004] In order to solve the above-mentioned problems, various attempts have been made to add additives such as antioxidants and ultraviolet absorbers to the photosensitive layer (for example, JP-A-62-105).
No. 151, JP-A-63-18366), at present, a technique that can satisfy all the required performances has not yet been established.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above points, and has as its object to stabilize ozone and ultraviolet rays by optimizing additives, and to stabilize the characteristics of electrophotography for a long period of time. It is to provide a photoreceptor.

[0006]

According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate according to the present invention.
Chemical formula [I-2], chemical formula [I-3] or chemical formula [I
-4].

The kina alkaloid represented by the chemical formula [I-1] is cinchonine, the kina alkaloid represented by the chemical formula [I-2] is cinchonidine, the kina alkaloid represented by the chemical formula [I-3] is quinine, and the chemical formula [I-4] Is a quinidine.

[0008]

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[0009]

It has been confirmed that the potential characteristics and the sensitivity characteristics do not change with time even when the photoreceptor is left in an ozone atmosphere or subjected to stress such as intense light irradiation by the above means. This is because the organic substance forming the photosensitive layer is not oxidized and deteriorated by ozone generated in the charging process, and is not deteriorated by photoreaction even when exposed to strong external light during maintenance. This is estimated as follows. That is, the additive reacts with a radical (which acts as a trap) formed by the reaction of ozone or ultraviolet light with an organic substance (particularly a charge transporting substance), and converts the radical into a stable compound.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a positively charged single-layer type electrophotographic photoconductor according to an embodiment of the present invention. This photoconductor is composed of a conductive substrate 1 as a support and a photosensitive layer 20. The photosensitive layer 20 contains the charge generating substance 3, the charge transporting substance 5, and the additive 2.

FIG. 2 is a sectional view showing a negatively charged laminated electrophotographic photosensitive member according to an embodiment of the present invention. This photoreceptor comprises a conductive substrate 1, a charge generation layer 4, and a charge transport layer 6. The charge generation layer 4 and the charge transport layer 6 constitute the photosensitive layer 21. The charge transport layer 6 contains the additive 2.

FIG. 3 is a sectional view showing a positively-charged laminated electrophotographic photosensitive member according to an embodiment of the present invention. This photoreceptor comprises a conductive substrate 1, a charge transport layer 6, a charge generation layer 4, and a coating layer 7.
It is composed of The charge transport layer 6, the charge generation layer 4, and the coating layer 7 constitute the photosensitive layer 22. The charge transport layer 6 contains the additive 2.

As the conductive substrate 1 as a support, a conductive substrate alone such as an aluminum cylinder or an aluminum vapor-deposited film, an alumite-ized surface of the conductive substrate, or a surface modification with a resin film or the like is used. What has been used is used. In the present embodiment, as the conductive substrate, an aluminum-made cylindrical substrate having a thickness of 1 mm, a length of 310 mm, and an outer diameter of 60 mm was washed and dried. As the material of the polymer dispersion film used for surface modification, casein, polyvinyl alcohol, nylon, polyamide,
An insulating polymer such as melanin or cellulose, a conductive polymer such as polythiophene, polypyrrole, or polyaniline, or a mixture of these polymers with a metal oxide powder or a low molecular compound is used.

The photosensitive layer 20 comprises a charge generating substance 3, a charge transporting substance 5, an additive 2, and a binder. Charge generation substance 3
The charge transport material 5 and the additive 2 will be described later. As the binder, for example, bisphenol Z-type polycarbonate (trade name PCZ300: manufactured by Mitsubishi Gas Chemical) represented by the chemical formula (VIII-6) is used. The charge generation layer 4 is composed of the charge generation substance 3 and a binder resin. As the charge generating substance 3, chemical formulas (II-1) to (II-6)
Various phthalocyanine compounds shown in the formula (II-
7) to various azo compounds represented by the chemical formulas (II-18), various polycyclic quinone compounds represented by the chemical formulas (II-19) to (II-26), and the chemical formulas (II-27) to (II-34) ) And derivatives thereof. Examples of the binder resin for the charge generation layer 4 include polycarbonate, polyester, polyamide, polyurethane, epoxy polyvinyl butyral, polyvinyl acetal, phenoxy resin, silicone resin, acrylic resin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, and homal resin. Cellulose resins, their copolymers, their halides, and cyanoethyl compounds are used.

[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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The charge transport layer 6 is composed of the charge transport material 5, the additive 2, and a binder resin. Specific examples of the charge transport material 5 include various hydrazone compounds represented by the chemical formulas (III-1) to (III-10) and derivatives thereof, and various butadiene compounds represented by the chemical formulas (IV-1) to (IV-8) -Based compounds and derivatives thereof, various amine-based compounds represented by the chemical formulas (V-1) to (V-14) and derivatives thereof, and various styryl-based compounds represented by the chemical formulas (VI-1) to (VI-10) and the like Derivative, chemical formula (VII-1) to chemical formula (VII-1)
Various distyryl compounds and their derivatives shown in 6) can be used alone or in combination.

[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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As the resin binder for the charge transporting layer, polycarbonate, polystyrene, polyphenylene ether, acrylic resin, etc. represented by the chemical formulas (VIII-1) to (VIII-6) can be used. The additive 2 added to the charge transport layer 6 has the chemical formula [I-
1], a kina alkaloid represented by the chemical formula [I-2], the chemical formula [I-3] or the chemical formula [I-4] is used. When the above-mentioned additives are used in combination with the compounds represented by the chemical formulas (IX-1) to (IX-49), a greater effect of preventing oxidation deterioration and light deterioration can be obtained. The effect of these additives is especially the bisphenol A type as a binder.
It is effective when biphenyl copolymerized polycarbonate is used.

[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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The coating layer has a function of receiving and holding a charge of corona discharge in a dark place, has a function of transmitting light which the charge generation layer is sensitive to, and has a function of transmitting light which is sensitive to the charge generation layer. It is necessary that the surface charge is neutralized and extinguished in response to the charge injection. As the coating material, an organic insulating film forming material such as polyamide, or a mixture of such an organic material and an inorganic material such as SiO ₂ , or a material such as a metal or a metal oxide that reduces electric resistance may be used. it can.

The case where the present invention is applied to a negatively-charged laminated photoreceptor will be described below. However, this embodiment does not limit the scope of the invention. Example 1 A polyamide having a number average molecular weight of 100,000 (trade name: T171,
4 parts by weight of Daicel-Hulls Co., Ltd. and styrene-maleic acid resin (trade names: Suprapearl AP, BASFJapan Lt)
d.) 1 part by weight of a resin coating solution prepared by dissolving 1 part by weight of a mixed solvent of 200 parts by weight of methanol and 100 parts by weight of 1-butanol was used to dip a 0.1 μm-thick resin film on the above-mentioned cylindrical substrate. And a conductive substrate as a support was produced.

1 part by weight of the bisazo compound represented by the chemical formula (II-14) as a charge generating substance, and 1 part by weight of a diallyl phthalate resin (trade name: DAP K, manufactured by Osaka Soda) as a binder resin were mixed with 150 parts by weight of methyl ethyl ketone. Then, the mixture was kneaded with a mixer for 3 hours to prepare a coating solution to prepare a coating solution for the charge generation layer. 1000 parts by weight of a compound represented by the chemical formula (V-8) and 1000 parts by weight of a bisphenol A type-biphenyl copolymer polycarbonate (trade name: BP-Pc: manufactured by Idemitsu Kosan) represented by the chemical formula (VIII-5) as a charge transporting substance; 20 parts by weight of cinchonine represented by the chemical formula (I-1) was dissolved in 7000 parts by weight of dichloromethane to prepare a charge transport layer coating solution.

Using the above coating solution, a charge generating layer and a charge transporting layer were sequentially formed on a support by a dipping method to prepare a photoreceptor. Example 2 A photoconductor was prepared by the same way as that of Example 1 except that the charge transport material of Example 1 was changed to the compound represented by the chemical formula (VII-1). Example 3 In the same manner as in Example 1 except that the charge transport material of Example 1 was replaced with a mixture of 500 parts by weight of the compound represented by the chemical formula (III-6) and 500 parts by weight of the compound represented by the chemical formula (IV-1) To produce a photoreceptor. Example 4 In the same manner as in Example 1 except that the charge transport material of Example 1 was changed to a mixture of 500 parts by weight of the compound represented by the chemical formula (V-1) and 500 parts by weight of the compound represented by the chemical formula (V-11) To produce a photoreceptor. Example 5 In the same manner as in Example 1 except that the charge transport material of Example 1 was replaced with a mixture of 200 parts by weight of the compound represented by the chemical formula (V-1) and 800 parts by weight of the compound represented by the chemical formula (VII-1) To produce a photoreceptor. Example 6 A photoconductor was prepared by the same way as that of Example 1 except that the additive of Example 1 was changed to cinchonine represented by the chemical formula (I-2). Example 7 A photoconductor was prepared by the same way as that of Example 1 except that the additive of Example 1 was changed to quinine represented by the chemical formula (I-3). Example 8 A photoconductor was prepared by the same way as that of Example 1 except that the additive of Example 1 was changed to quinidine represented by the chemical formula (I-4). Example 9 The additive of Example 1 was obtained by adding 20 parts by weight of cinchonine represented by the chemical formula (I-1) and cinchonidine 2 represented by (I-2)
A photoconductor was prepared in the same manner as in Example 3, except that the mixture was changed to 0 parts by weight. Example 10 A photoconductor was prepared in the same manner as in Example 4, except that the additive of Example 1 was replaced with a mixture of 20 parts by weight of cinchonine represented by the chemical formula (I-1) and 20 parts by weight of quinine represented by (I-3). Was prepared. Example 11 A photoconductor was prepared in the same manner as in Example 5, except that the additive of Example 1 was replaced with a mixture of 20 parts by weight of cinchonine represented by the chemical formula (I-1) and 20 parts by weight of quinidine represented by (I-4). Was prepared. Example 12 Bisphenol A type-biphenyl copolymer polycarbonate (trade name BP-Pc: manufactured by Idemitsu Kosan Co., Ltd.) as a binder of Example 1 was replaced with bisphenol Z type polycarbonate represented by chemical formula (VIII-6) (trade name PCZ300: Mitsubishi Gas) A photoreceptor was produced in the same manner as in Example 1 except that the photoreceptor was replaced. Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1, except that the cinchonine represented by the chemical formula (I-1) was not added. Comparative Example 2 A photoconductor was prepared in the same manner as in Example 3, except that the cinchonine represented by the chemical formula (I-1) was not added. Comparative Example 3 A photoconductor was prepared in the same manner as in Example 4, except that the cinchonine represented by the chemical formula (I-1) was not added. Comparative Example 4 A photoconductor was prepared in the same manner as in Example 5, except that the cinchonine represented by the chemical formula (I-1) was not added. Comparative Example 5 Cinchonine represented by Chemical Formula (I-1) and Chemical Formula (I-
Example 9 except that cinchonidine shown in 2) was not blended.
A photoreceptor was prepared in the same manner as described above. Comparative Example 6 Cinchonine represented by Chemical Formula (I-1) and Chemical Formula (I-
A photoconductor was prepared in the same manner as in Example 10, except that the quinine shown in 3) was not blended. Comparative Example 7 Cinchonine represented by Chemical Formula (I-1) and Chemical Formula (I-
A photoconductor was prepared by the same way as that of Example 11 except that quinidine shown in 4) was not added.

The electrophotographic characteristics of the photoreceptors produced in the above Examples and Comparative Examples were evaluated. In order to evaluate potential fluctuations during continuous use, various photoconductors were mounted on a copier in which the operating conditions of the charging mechanism, exposure mechanism, and static elimination mechanism were fixed, and A3 paper was used in an atmosphere of normal temperature and normal humidity (20 ° C., 60 RH). 50,000 sheets of running test are performed and the potential of blank paper at the start of running (Vw)
And the black paper potential (Vb) were measured, and each potential change amount (ΔVw, ΔVb) at the end of running was obtained. Further, for the purpose of evaluating the ozone resistance, each photoconductor was exposed to an environment having an ozone concentration of 100 ppm for 4 hours, and the half-life exposure before and after the exposure was measured and compared.

Further, for the purpose of evaluating the resistance to strong light fatigue, each photoreceptor is irradiated with light of 1000 lux for 1 hour, the initial charging potential (Vs) before irradiation under a constant charging condition is measured, and after the irradiation is completed. The charge potential change amount (ΔVs) was obtained. Table 1 shows the results.

[0043]

[Table 1]

As can be seen from Table 1, photoreceptors which do not contain the quina alkaloids represented by the chemical formulas [I-1], [I-2], [I-3] or [I-4] according to the comparative examples The characteristics of the photoreceptor deteriorate due to exposure to ozone or irradiation with strong light, and the potential fluctuation due to a running test in an actual machine deviates from a practical range. The effect of preventing deterioration when bisphenol A type-biphenyl copolymerized polycarbonate is used as a binder is large.

[0045]

According to the present invention, the chemical formula [I-1], the chemical formula [I-2] and the chemical formula [I] are used as additives in the photosensitive layer.
-3] or the kina alkaloid represented by the chemical formula [I-4], so that an electrophotographic photoreceptor having stable characteristics over a long period of time without deterioration of photoreceptor characteristics due to ozone exposure or intense light irradiation can be obtained. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a positively charged single-layer type electrophotographic photoconductor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a negatively charged laminated electrophotographic photoconductor according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a positively-charged laminated electrophotographic photoconductor according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive substrate 2 additive 3 charge generating substance 4 charge generating layer 5 charge transporting substance 6 charge transporting layer 7 coating layer 20 photosensitive layer 21 photosensitive layer 22 photosensitive layer

────────────────────────────────────────────────── (5) References JP-A-3-23463 (JP, A) JP-A-62-29882 (JP, A) JP-A-47-34585 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) G03G 5/05 CAS

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, wherein the photosensitive layer has a chemical formula [I-
1], a photoreceptor for electrophotography, comprising a kina alkaloid represented by the chemical formula [I-2], the chemical formula [I-3] or the chemical formula [I-4]. Embedded image