JPH0356968A - Electrophotographic selenium sensitive body - Google Patents

Abstract

PURPOSE:To easily form a surface layer on the surface of a photosensitive layer in good adhesion to it without impairing various characteristics with good wettability to it by forming the surface layer composed of alkoxysilanol and acrylic polyol and having a thickness of 0.3 - 1.0 mum. CONSTITUTION:The photosensitive body is provided on a conductive substrate 1 made of an aluminum alloy with the photosensitive layer 2 made by vapor deposition of As2Se3 and on this layer the surface layer 3 composed of alkoxysilanol and acrylic polyol and having a thickness of 0.3 - 1.0 mum, thus permitting the obtained surface layer 3 to be adjusted in specific resistivity by adding the alkoxysilanol, and accordingly, to be easily formed with good wettability on the photosensitive layer 2 without impairing various characteristics of the photosensitive layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a selenium photoreceptor for electrophotography, and more specifically, the present invention relates to a selenium photoreceptor for electrophotography. The present invention relates to a selenium photoreceptor for electrophotography, which includes a layer made of an organic material that has both the function of preventing reflection of light projected onto the photosensitive layer.

[Prior Art] Photoreceptors used in electrophotographic devices using the Carlson process are broadly classified into those with a functionally separated multilayer structure and those with a single layer structure, based on the structure of their photosensitive layers. In the former, the basic structure is a charge generation layer in which pairs of electrons and holes are generated by the incidence of light for latent image formation, and a charge transport layer that transports the generated charges; in the latter, the charge generation layer , the basic structure is a single layer with charge transport ability.

Most of the electrophotographic devices developed in the past kept the basic structure of the photoreceptor mounted thereon.

In the past, photoreceptors with a protective layer on the surface had been put into practical use, but these were mostly used only in special electrophotographic methods other than the Carlson process. Recently, as demands for image quality have become increasingly strict, electrophotographic devices using the Carlson process are also required to have a photoreceptor with a surface protective layer, and a method of providing a surface protective layer that can also be used in the Carlson process Various proposals have been made.

For example, JP-A-58-139154, JP-A-58
As is known in JP-A-217942 and JP-A-57-16459, a method of providing a cross-linked polymer or copolymer as a protective layer; As is well known, fluororesin. Method of providing silicone {sealant 1 polyester resin 1 aromatic polyamide resin etc. as a protective layer, JP-A-59-
15940, JP-A-59-15941, JP-A-56-21134, and methods of providing an inorganic layer, as well as JP-A-58-130343, JP-A-58-130343.
As is known from Japanese Patent Application Laid-open No. 57-30846, metals,
A method of providing a polymer resin layer containing an inorganic substance such as a metal oxide has been proposed.

[Problem to be solved by the invention]

However, few conventional surface protective layers have yielded satisfactory results, and there have also been cases of property deterioration due to side effects of the surface protective layer.

In other words, the method of using a polymeric fat layer as a protective layer requires a condensation catalyst, which complicates the process, and the substance used for the catalyst may have an adverse effect on the photosensitive layer consisting of a selenium-based material phase. In addition, a baking process is required to form a hardened film, the wettability with the photosensitive layer made of selenium-based material is poor, and advanced techniques and techniques are required for application. Due to this, there was a problem of lowering the sensitivity of the photoreceptor and accelerating the toner filming cycle.

Furthermore, in the method of using an inorganic layer as a protective layer, the technology for uniformly applying the inorganic layer is generally very sophisticated, and it also requires a lot of equipment, which inevitably leads to high costs.

On the other hand, the method of using a polymer resin layer containing an inorganic substance is the most practical, but unless the inorganic substance to be dispersed and the base resin are carefully examined and the blending ratio etc. are not carefully controlled, toner filming may occur. This may lead to early image defects, and furthermore, the film quality may deteriorate due to the addition of inorganic substances, resulting in image defects or film peeling.

Furthermore, in any of the above-mentioned protective layers, absorption of exposure light by the protective layer and further surface reflection may cause a problem in that light reaching the photosensitive layer decreases and sensitivity decreases.

The problem to be solved by this invention is that it can be easily formed on a photosensitive layer made of a selenium-based material with good wettability and without impairing the properties of the photosensitive layer, and that the photosensitive layer can be formed mechanically or chemically. To provide an excellent selenium photoreceptor for electrophotography, which has a surface layer that has both the function of protecting the photosensitive layer and the function of preventing reflection of exposure light projected onto the photosensitive layer, and has high sensitivity and durability that can withstand practical use. There is a particular thing.

[Means to solve the problem]

According to the present invention, the above problem can be solved by applying a photosensitive layer made of a selenium-based material provided on a conductive substrate, which is made of alcoquine/lanol and acrylic polyol and has a thickness of 0.
This problem can be solved by providing a selenium photoreceptor for electrophotography with a surface layer having a thickness of 3 μm or more and less than 1.0 μm.

[Effect]

Acrylic polyol can form a highly hard film that firmly adheres with good wettability without adversely affecting the underlying photosensitive layer made of selenium-based material, and by adding alcoquinranol, the ratio of the film can be increased. Since the resistance can be adjusted, the mixed material of the two has the ability to chemically protect the photosensitive layer without deteriorating electrophotographic properties such as charged potential and residual potential of the photosensitive member. You can shape the layers. In addition, the mixed material of both has good transmittance to light in the wavelength region where the absorption of light is maximum by the selenium-based material used as a charge-generating substance used in the photosensitive layer.

On the other hand, in order to prevent light reflection on the surface of a photosensitive layer made of a selenium-based material, a material having a refractive index between that of the selenium-based material and the refractive index of the air surrounding the photosensitive layer is used. It is preferable to form a film on the surface of the photosensitive layer. In addition, the film thickness may be set to λ/(4./5) or an odd multiple thereof, but considering the light absorption of the anti-reverse film itself, it is optimal to set it to λ/(4./5). , n is the refractive index of selenium-based material 1, and λ is the exposure wavelength). Since the refractive index of the selenium-based material is about 2.4, the optimum film thickness is 0.06 μm to 0.12 μm when visible light is used for exposure.

The refractive index of a mixed material of alkoxysilanol and acrylic polyol is about 1.4 to 1.8;
The surface layer formed with the dielectric material can suitably serve as an antireflection coating for a photosensitive layer made of a selenium-based material. However, since the photoreceptor is used while its surface is rubbed with a blade etc. when forming an image, if this surface layer is a thin film with the optimum thickness for an anti-reflection film as mentioned above, it will last for a short time. This results in wear and tear, resulting in insufficient functionality as a protective layer.

As a result of our pursuit of a film thickness that would be practical as a protective layer and also function as an anti-reflection film, improving the sensitivity of the photoreceptor compared to when no surface layer was provided, we decided to increase the thickness of the surface layer. They found that it is preferable to set the thickness to 0.3 μm or more and less than 1.0 μm.

〔Example〕

FIG. 1 is a schematic cross-sectional view of an actual example of the photoreceptor of the present invention, in which a conductive substrate 1 made of aluminum is coated with
Photosensitive layer 2 consisting of a vapor-deposited film of As2Se with a film thickness of 53 μm
, and further has a surface layer 3 thereon. Surface layer 3 is alkoxine lanol (Tokyo Ohka Kogyo ■tjl OCD
Type 6) and acrylic polyol (Kansai Paint■
It was formed by applying a mixture of PG-60) and PG-60) at a weight mixing ratio of 7:3.

In order to investigate the effect of the surface layer, the characteristics of the photoreceptor before and after the surface layer 3 was formed were investigated. The results are shown in Table J. In Table 1, the charging potential is the surface potential when the photoconductor surface is charged by corona discharge with the corona discharge voltage set so that the photoconductor surface potential is 700V, and the charging ability is (the photoconductor surface potential at the time of charging). It is the ratio of the current flowing into the photoreceptor (X 10') divided by the charged potential, and the sensitivity is the surface potential when the charged photoreceptor surface is irradiated with a constant amount of light.

Table 1 As seen in Table 1, in both Examples 1 and 2, the sensitivity was improved by about 50 V by shaping the surface layer. Further, FIGS. 2 and 3 respectively show the spectral sensitivity characteristics of Example 12, and in both cases, the spectral sensitivity is improved by providing the surface layer. When the reflectance of the photoreceptor surface in Example 1.2 was measured by projecting light with a peak wavelength of 600 nm, it was 0.5 when there was no surface layer.
5, but by providing the surface layer it became 0.35, which was a decrease of 0.02. It is clear that the antireflection function of the surface layer increases the amount of light that reaches the photosensitive layer and increases the sensitivity of the photoreceptor.

In Table 1, the residual potential increases due to the shape of the surface layer, but this is a value that poses no practical problem.

Furthermore, the adhesion of the surface layer was also good, and as a result of an image output test carried out by attaching it to an electrophotographic device, good quality images were obtained without image fading even in a high humidity atmosphere. Furthermore, when a continuous image printing test was conducted, it was found that the printing durability was sufficient for practical use.

When the thickness of the surface layer was less than 1 μm, an increase in the sensitivity of the photoreceptor was observed because the increase in light intensity due to the antireflection function was greater than the decrease in light intensity due to light absorption within the surface layer. Furthermore, it was found that if the thickness of the surface layer was 0.3 μm or more, printing durability sufficient for practical use could be obtained.

In the above examples, the blending ratio of alcoholic silanol and acrylic polyol was 7:3, but the blending ratio is not limited to this. Furthermore, although the photosensitive layer of the photoreceptor was a single layer made of As2Se3, Se, As.
Ses. Of course, the present invention is also effective in the case of a functionally separated multi-N structure photoreceptor having a photoreceptor layer made of a laminated layer of Se/Te alloy, Se/As alloy, or the like.

〔Effect of the invention〕

According to this invention, the surface of the photosensitive layer of a photoreceptor including a photosensitive layer made of a selenium-based material is made of an alkohquinone lanol and an acrylic polyol and has a thickness of 0.3 μm or more and 1.0 μm.
A surface layer of less than m is provided.

This surface layer has good wettability on the photosensitive layer, can be easily formed with good adhesion without impairing various properties of the photosensitive layer, and has the ability to mechanically and chemically protect the photosensitive layer. To obtain an excellent selenium photoreceptor for electrophotography that has a function of preventing reflection of exposure light projected onto the photosensitive layer, and has high sensitivity and durability sufficient for practical use by providing such a surface layer. I can do it.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of the photoreceptor of the present invention;
FIGS. 2 and 3 are diagrams showing the spectral sensitivity characteristics of Examples 1 and 2, respectively. 1 conductive substrate, 2 photosensitive layer, 3 surface layer. Figure 1 Wavelength (nm); Reverse length (nm) Figure 2 Figure 3

Claims (1)

[Claims] 1) A surface layer made of an alkoxysilanol and an acrylic polyol and having a thickness of 0.3 μm or more and less than 1.0 μm is provided on a photosensitive layer made of a selenium-based material provided on a conductive substrate. A selenium photoreceptor for electrophotography characterized by: