JP2000155431A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor having good characteristics and capable of exhibiting expected performance by reducing the content of degenerated components formed by the decomposition of an electric charge transferring material in an electric charge transferring layer to a prescribed value or below. SOLUTION: Since it is actually difficult to perfectly prevent the formation of degenerated components by the decomposition of an electric charge transferring material in a coating fluid for an electric charge transferring layer, it is important that the content of degenerated components is made reasonably low. In order to inhibit the formation of degenerated components, light shielding, preservation and handling at low temperature, the addition of an antioxidant and a UV absorber and the use of a dehydrating agent are effective. The formation of degenerated components is thus inhibited and the amount of degenerated components included in the electric charge transferring layer is reduced to <=1.0% to the electric charge transferring material with respect to peak area ratio in chromatogram by liquid chromatography. It is also important in the production control of a photoreceptor that the amount of degenerated components incorporated by coating into the photosensitive layer of the photoreceptor, in particular the electric charge transferring layer is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor for electrophotography (hereinafter, also simply referred to as "photoconductor").

[0002]

2. Description of the Related Art In electrophotographic technology, an image having both immediateness, high speed, and high resolution can be obtained.
Widely used in fields such as printers and faxes. The photoreceptor used in such electrophotography has conventionally used many inorganic photoconductive materials such as selenium, a selenium alloy, zinc oxide, and cadmium sulfide. Exploiting advantages such as light weight, the development of photoreceptors using organic photoconductive materials has been actively pursued.

Among such organic photoconductors, a so-called function-separated laminated organic photoconductor in which a charge generation layer and a charge transport layer are separated from each other is formed by forming each layer with a material optimal for each function and combining them. , The sensitivity can be greatly improved. Further, it has many advantages such as setting of spectral sensitivity according to a desired wavelength of exposure light, and is used in electrophotographic apparatuses such as copiers, printers, and faxes. With the progress of computerization, these electrophotographic apparatuses are required to have higher speed and higher resolution.

Many of the function-separated laminated organic photoreceptors that are currently in practical use are obtained by sequentially laminating a charge generation layer and a charge transport layer on a conductive substrate. Such a photoreceptor
First, a charge generation material was dispersed and dissolved in an organic solvent together with a binder on a substrate, and a coating solution in which the charge generation material was dissolved was applied and dried to form a charge generation layer, and then the charge transport material was dissolved in the organic solvent together with the binder. The charge transport layer is formed by applying and drying a coating liquid. Basically, with such a layer configuration, basic performance for image formation as a photoreceptor can be exhibited.

[0005]

However, such a coating solution for forming a layer is liable to be deteriorated, and it is often impossible to produce a photoreceptor exhibiting the desired performance. Such alteration of the coating solution is often caused by the decomposition of components in the solution by the action of heat, light, moisture absorption, etc., resulting in the generation of decomposition products and reaction products. In addition, the photoconductor cannot exhibit its intended performance.

In view of the above circumstances, the present invention provides an electrophotographic photoreceptor having good characteristics by clarifying the relationship between the generation of a deteriorated component and the characteristics of the photoreceptor during the production of the photoreceptor. The purpose is to do so.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by reducing the content of the altered component accompanying the decomposition of the charge transport material in the charge transport layer to a predetermined amount or less. The inventors have found that the above object can be achieved, and have completed the present invention.

That is, the electrophotographic photoreceptor of the present invention comprises:
In the electrophotographic photoreceptor having at least the charge transport layer, the content of the altered component accompanying the decomposition of the charge transport material in the components of the charge transport layer has a peak area when analyzed by a liquid chromatography method. It is characterized by a ratio of not more than 1.0% based on the charge transporting material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to an example of a function-separated laminated electrophotographic photosensitive member. Function-separated laminated photoreceptors are generally produced by sequentially laminating a charge generation layer and a charge transport layer on a conductive substrate, and optionally providing an undercoat layer between the substrate and the charge generation layer. Alternatively, a protective layer may be provided on the outermost layer surface.

In the case of a laminated photoreceptor, examples of the charge generating material used for the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, and the like. Various photoconductive materials such as organic pigments such as indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used.These fine particles can be used, for example, polyester resin, polyvinyl acetate, polyacrylate, polymethacrylic Acid ester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin,
It is used in a form adhered with various binder resins such as epoxy resin, urethane resin, cellulose ester and cellulose ether. In this case, the usage ratio of the charge generation material is 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin.
It is generally within the range of parts by weight, and the film thickness is usually 0.1%.
5 μm to 0.6 μm is preferred.

Next, the charge transport layer comprises an enamine compound,
A styryl compound, a hydrazone compound, an amine compound, and a butadiene compound are formed into a solution together with a binder resin compatible with these, for example, polyester, polycarbonate, polystyrene, polyacrylate, polymethacrylate, and the like. Thick 10
It is formed by coating with a thickness of 40 μm. If necessary, the charge transport layer may contain various additives such as an antioxidant, an ultraviolet absorber, and a leveling agent.

[0012] It is practically difficult to completely suppress the formation of altered components due to the decomposition of the charge transport material in the charge transport layer coating solution. Therefore, it is industrially important that the content of the altered component in the photoreceptor is not excessively increased. In order to suppress the formation of such altered components, it is effective to shade, store and handle at a low temperature, add an antioxidant and an ultraviolet absorber, and use a dehydrating agent. In this way, the generation of the altered component can be specifically suppressed, and the amount of the altered component mixed with the charge transporting material is 1.0% or less in the peak area ratio of the chromatogram by the liquid chromatography method. It is necessary to suppress it. It is also important in the production control of the photoreceptor to suppress the amount of altered components taken into the photosensitive layer of the photoreceptor by coating, in particular, into the charge transport layer.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited to these Examples. Example 1 A coating solution was prepared by dispersing and dissolving 1 part by weight of an X-type metal-free phthalocyanine and 1 part by weight of a vinyl chloride copolymer resin (MR110, manufactured by Zeon Corporation) in 100 parts by weight of dichloromethane. The charge generation layer was formed by applying this coating solution on an alumite-treated aluminum cylindrical substrate by dip coating and drying. The film thickness after drying was 0.2 μm.

Next, the following equation (1): Was dissolved in 10 parts by weight of dichloromethane. This solution was immediately applied on the charge generation layer and dried to form a charge transport layer. The film thickness after drying was 20 μm. When the components in the charge transport layer of this photoreceptor were analyzed by liquid chromatography, no altered components due to the decomposition of the charge transport material could be detected.

Example 2 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoconductor was prepared by the same method as that of Example 1 except that the coating was performed after accelerated deterioration of the coating solution by sun exposure. The components in the charge transport layer of this photoreceptor were analyzed by liquid chromatography, spectrum analysis, mass spectrometry and nuclear magnetic resonance, and the following formulas (2) to (4) were obtained. Altered components were detected. When these contents were analyzed by liquid chromatography, the total amount of altered components accompanying the decomposition of the charge transporting material was 0.3% in the peak area ratio with respect to the original charge transporting material.

Example 3 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoconductor was prepared by the same method as that of Example 1 except that the coating was performed after accelerated deterioration of the coating solution by sun exposure. When the components in the charge transport layer of the photoreceptor are analyzed by liquid chromatography, the altered components accompanying the decomposition of the charge transport material have a total peak area ratio of 0.1 to the original charge transport material.
8%.

COMPARATIVE EXAMPLE 1 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoreceptor was prepared in the same manner as in Example 1, except that coating was performed after accelerated deterioration by daylight exposure. When the components in the charge transport layer of this photoreceptor were analyzed by liquid chromatography, the altered components accompanying the decomposition of the charge transport material were 1.5% in total in terms of peak area ratio with respect to the original charge transport material. .

Example 4 The charge transport material was represented by the following formula (5): A photoconductor was prepared by the same method as that of Example 1 except that the amount of compound was 1 part by weight. When the components in the charge transport layer of the photoreceptor were analyzed by liquid chromatography, no altered components due to the decomposition of the charge transport material could be detected.

Example 5 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoconductor was prepared by the same method as that of Example 4 except that coating was performed after accelerated deterioration of the coating solution by sun exposure. The components in the charge transport layer of this photoreceptor were analyzed by liquid chromatography, spectrum analysis, mass spectrometry, and nuclear magnetic resonance, and the following formulas (6) to (8) were obtained. Altered components were detected. When these contents were analyzed by a liquid chromatography method, the total amount of altered components accompanying the decomposition of the charge transporting material was 0.2% in the peak area ratio with respect to the original charge transporting material.

Example 6 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoconductor was prepared by the same method as that of Example 4 except that coating was performed after accelerated deterioration of the coating solution by sun exposure. When the components in the charge transport layer of the photoreceptor are analyzed by a liquid chromatography method, the altered components accompanying the decomposition of the charge transport material have a total peak area ratio of 0.1 to the original charge transport material.
7%.

COMPARATIVE EXAMPLE 2 A coating solution for forming a charge transport layer was applied to a room under a fluorescent lamp.
A photoconductor was prepared by the same method as that of Example 4 except that coating was performed after accelerated deterioration of the coating solution by sun exposure. When the components in the charge transport layer of this photoreceptor are analyzed by liquid chromatography, the altered components accompanying the decomposition of the charge transport material have a total peak area ratio to the original charge transport material of 1.
3%.

The characteristics of the photoreceptor obtained as described above were evaluated. Each photoreceptor was tested for -6
After charging to 00 V, exposure light having a wavelength of 780 nm
Irradiation was performed at an intensity of μW / cm ² , and the surface potential (residual potential) after exposure at 5 μJ / cm ² was evaluated. The results obtained are shown in Table 1 below.

[0023]

[Table 1]

When the residual potential exceeds 50 V, practically, a defect occurs in an image, which results in a failure. However, from the above results, Examples 1 to 6 according to the present invention show Comparative Examples 1 and 2
It can be seen that the photosensitive member has better photoreceptor characteristics as compared with.

[0025]

As described above, in the photoreceptor of the present invention, the content of the altered component accompanying the decomposition of the charge transport material in the components of the charge transport layer is analyzed by liquid chromatography. By setting the peak area ratio to 1.0% or less with respect to the charge transport material, good electric characteristics can be obtained.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having at least a charge transport layer, wherein the content of an altered component accompanying the decomposition of the charge transport material in the components of the charge transport layer is analyzed by a liquid chromatography method. A charge transfer material having a peak area ratio of 1.0% or less.