JPS62144175A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To reduce the dark decay of electrostatic charge potential by interposing an intermediate layer between an electrically conductive substrate and a photoconductive layer of amorphous silicon and using a dried and hardened substance of a soln. contg. at least one kind of org. aluminum compound as the material of the intermediate layer. CONSTITUTION:A photoconductive layer is made of a P type semiconductor contg. amorphous silicon contg. H as the principal component and B as an impurity and further contains at least one among C, N and O. An intermediate layer is made of a dried and hardened substance of a soln. contg. at least one kind of org. aluminum compound. The compound used may be trisacetylacetonatoaluminum. Such atoms are preferably contained because they are effective in increasing the dark resistance, photosensitivity and electrostatic chargeability (electrostatic charge potential per unit film thickness) of a photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor, and particularly to an electrophotographic photoreceptor using amorphous silicon in the photosensitive layer.

In the conventional electrophotographic method, an electrostatic latent image is formed by charging a photoreceptor and exposing it to light, and after developing this latent image with a developer called Tonani,
This is a method of transferring and fixing a toner image onto transfer paper to produce a copy. The photoreceptor used in this electrophotographic method basically has a photosensitive layer laminated on a conductive substrate. Conventionally, the materials constituting the photosensitive layer include inorganic photosensitive materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide, or polyvinylcarbazole, trinitrofluorenone, bisazo pigments, phthalocyanine, etc.
Organic photosensitive materials such as pyrazoline and hydrazone are known, and are used as a single layer or FL''I layer as a photosensitive layer.However, these conventionally used photosensitive layers lack durability and heat resistance. , there are still problems to be solved in terms of photosensitivity, etc.

In recent years, photoreceptors using amorphous silicon as the photosensitive layer have been known, and various attempts have been made to modify them. This photoreceptor using amorphous silicon has an amorphous silicon film formed on a conductive substrate using a glow discharge decomposition method using 7-run (SI84) gas. Hydrogen atoms are incorporated into the material to exhibit photoconductivity. This amorphous silicon photoreceptor has a photosensitive layer that has a high surface hardness, is resistant to scratches, is resistant to abrasion, has high heat resistance, and has excellent mechanical strength. Furthermore, amorphous silicon has a wide spectral sensitivity range and has excellent photosensitivity, such as high photosensitivity. However, on the other hand, photoreceptors using amorphous silicon have the disadvantages of large dark decay (and insufficient charging potential even when charged). , when an electrostatic latent image is formed by imagewise exposure and then developed, the surface charge on the photoreceptor is attenuated until the imagewise exposure process or even the charge on the part that has not been exposed to light during the development process. As a result, the charging potential necessary for development is not available.The attenuation of this charging potential is also susceptible to changes due to the influence of environmental conditions, and especially in high temperature and high humidity, the charging potential decreases significantly.

Furthermore, when an amorphous silicon photoreceptor is used repeatedly, its charging potential gradually decreases. If a copy is made using a photoreceptor with such a large dark attenuation of the charged potential, the copy will have low image density and poor reproducibility of halftones.

OBJECTS OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks of photoreceptors using amorphous silicon.

Furthermore, the object of the present invention is to use amorphous silicon, and
An object of the present invention is to provide an electrophotographic photoreceptor in which the dark decay of the charged potential is extremely small.

Another object of the present invention is to provide a photoreceptor for electrophotography whose charging characteristics are not affected by changes in the snow surrounding the external environment.

Another object of the present invention is to provide an electrophotographic photoreceptor with excellent image quality even after repeated use.

Furthermore, another object of the present invention is to provide an electrophotographic photoreceptor having excellent electrophotographic properties such as mechanical strength, durability, heat resistance, and photosensitivity.

Structure of the Invention As a result of extensive research, the present inventor has found that conductivity) 5. An intermediate layer is provided between the photoconductive layer and the photoconductive layer made of amorphous silicon, and the intermediate layer contains at least one type of organoaluminum compound. It has been found that the above object can be achieved by the photoconductive layer.The photoconductive layer is a P-type semiconductor mainly composed of amorphous silicon and containing boron atoms as impurities, and further contains carbon atoms, nitrogen atoms, or oxidized atoms. One containing at least 1+ heavy atoms is used.

Thus, according to the present invention, in an electrophotographic photoreceptor comprising an intermediate layer and a photoconductive layer sequentially formed on a conductive substrate, the photoconductive layer is made of amorphous silicon containing Mizuki atoms. A solution comprising a P-type semiconductor containing boron atoms as an impurity and further containing at least one type of carbon atom, nitrogen atom, or oxygen atom, and the intermediate layer containing at least one type of organoaluminum compound. Provided is an electrophotographic photoreceptor comprising a dry cured product.

Examples of the organic aluminum compound □ used to form the intermediate layer of the electrophotographic photoreceptor of the present invention include aluminum trisacetylacetonate, aluminum methoxide, aluminum ethoxide, aluminum isopropoxide, aluminum-n-propoxide, aluminum-5ec-butoxide, aluminum-n
-butoxide, etc.

In order to obtain the electrophotographic photoreceptor of the present invention, a solution of one or more of the above organoaluminum compounds dissolved in a suitable solvent is coated. Further, at this time, a solution obtained by mixing these organoaluminum compounds with an organosilicon compound may be used. As this organosilicon compound, compounds generally called Nran coupling agents are suitable, such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, T-glycidoxypropyltrimethquine, etc. Nran, T-mequaacryloxypropyltrimethoxyrane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) T-aminopropylmethyldimethoxysilane, r-chloropropyltrimethoxyrane, γ-mercaptopropyltrimethoxysilane, T-aminopropyltriethoxysilane,
Methyltrimethoxysilane, dimethyldimethoxylan,
Examples include trimethylmonomethoxysilane, diphenyldimethoxysilane, diphenyljethoxysilane, and monophenyltrimethoxysilane. When such silane coupling agents are mixed and used, it is preferable that the silane coupling agents account for 5 to 50% of the total solid weight.

Thus, a solution containing an organoaluminum compound and optionally an organosilicon compound is applied onto the photoconductive layer.
The electrophotographic photoreceptor of the present invention can be obtained by coating by spray coating, dip coating, knife coating, roll coating, or the like, followed by dry curing. The dry smoke curing temperature can be set at any temperature between 100 and 100°C. The thickness of the final surface layer (i) can also be set arbitrarily, but preferably 0.1 to 10 .mu.m, particularly 1 .mu.m or less.

The photoconductive layer mainly composed of amorphous silicon is S i II
, , Si2+-16,513HIl, 314H+o, etc., or a mixture thereof as a raw material, and is formed on the IF by a method such as a glow discharge method, a sputtering method, an ion blating method, or a vacuum evaporation method. . Among them, plasma CVD (Chemical
A method of glow discharge decomposition of silane (SiH=) gas, etc. by the Vapor Deposition method (
The glow discharge method) is preferable from the viewpoint of controlling the amount of hydrogen contained in the film. Further, in this case, in order to more efficiently contain hydrogen, water 1 (H2) gas may be separately introduced into the plasma CVD apparatus at the same time as silane gas or the like.

The photoconductive layer of the electrophotographic photoreceptor of the present invention is a P-type semiconductor mainly composed of amorphous silicon containing hydrogen atoms and containing boron atoms as impurities. For this addition of boron atoms, diborane (B2H6) gas is usually used as a raw material.

In this case, the amount of boron atoms added is 0.01 to 1 at%
That's about it.

Further, in the electrophotographic photoreceptor according to the present invention, the photoconductive layer is made of a P-type semiconductor mainly composed of amorphous silicon containing hydrogen atoms and containing boron atoms as impurities,
Furthermore, it contains at least one type of carbon atom, nitrogen atom, or acid atom. The content of such atoms is
In particular, an increase in the dark resistance of the photosensitive layer film, an increase in photosensitivity, and furthermore,
This is preferable from the viewpoint of increasing charging ability (charging potential per unit film thickness).

Furthermore, it is also possible to add an element such as germanium (Ge) to the photoconductive layer film for the purpose of increasing the sensitivity of the photoreceptor in the long wavelength range. Further, by adding halogen atoms, it is also possible to increase the dark resistance.

Thus, in order to prepare the photoconductive layer of the electrophotographic photoreceptor of the present invention, hydrogen silicon gas as the main raw material and hydrogen gas as desired are used together with these gases in a plasma CVD 9 apparatus. , a gaseous compound containing necessary elements may be introduced to perform glow discharge decomposition. As described above, effective discharge conditions for forming a photoconductive layer made of amorphous silicon by the plasma CVD method include, for example, in the case of AC discharge, the frequency is usually 0.1 to 30 MHz, and the vacuum during discharge. The temperature is 0.1 to 5 Torr, and the substrate heating temperature is 100 to 4
0i]°C. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon is 1-100 μm, particularly 10-50 μm.
It is preferable to set it to m.

As the conductive substrate, a metal such as aluminum, nickel, chromium, stainless steel, or brass, a plastic sheet or glass having a conductive film, or paper treated to be conductive can be used. Moreover, the shape of the conductive substrate can be any shape such as a cylindrical shape, a flat plate shape, an endless belt shape, or the like.

EXAMPLES Next, the electrophotographic photoreceptor of the present invention will be further explained with reference to comparative examples and examples of the present invention.

Comparative Example 1: A cylindrical/1 substrate was installed at a predetermined position in a reaction chamber of a capacitively coupled plasma CVD apparatus, the substrate temperature was maintained at a predetermined temperature of 250°C, and 100% silane (S) was placed in the reaction chamber.
i H4) gas at 120CG/min, hydrogen dilution lOO
Oppm Sibolaf (B2H6) gas at 30cc per minute,
100% ethylene (C2H,) gas was introduced at a rate of 15 cc per minute, and 100% hydrogen (H2) gas was introduced at a rate of 75 cc per minute, and the internal pressure inside the reaction tank was maintained at 0.5 Torr. high-frequency power was applied to generate glow discharge, and the output of the high-frequency power source was maintained at 85W. In this way, a thickness of 2
A photoreceptor was obtained having a photoconductive layer having a thickness of 5 μm and consisting of a P-type semiconductor mainly composed of amorphous silicon and containing boron atoms and carbon atoms as impurities. When the photoreceptor thus ranked first was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density sufficient for practical use was not obtained.

Example 1: The same cylindrical A1 substrate as in Comparative Example 1 was coated with a solution consisting of 1 part by weight of aluminum trisacetylacetonate and 30 parts by weight of isopropyl alcohol for 25 hours.
It was dried and cured in an oven at 0° C. for 2 hours to provide an intermediate layer with a thickness of 0.1 μm. Next, on this intermediate layer, by the same method as in Comparative Example 1, a photoconductive layer mainly composed of amorphous silicon having the same content as in Comparative Example 1 was provided with approximately the same thickness as in Comparative Example 1. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. In addition, although the copying operation was repeated 50,000 times, no decrease in image density was observed. was maintained at a predetermined temperature of 250°C, and 100% silane (Si
H,) gas at 12 Qcc per minute.

Hydrogen dilution of 11000pp diborane (82H6) gas at 30cc/min, 100% nitrogen (N2) gas at 90cc/min
cc, plus 100% hydrogen (H2) gas per minute at IQcc
After maintaining the internal pressure in the reaction tank at 5 Torr, high frequency power of 13.56 MHz was applied to generate a glow discharge, and the output of the high frequency power source was maintained at 85 W. In this way, the cylindrical A, &
A photoreceptor was obtained having a photoconductive layer having a thickness of 25 μm on a substrate and consisting of a P-type semiconductor mainly composed of amorphous silicon and containing boron atoms and nitrogen atoms as impurities. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method, was it suitable for practical use? ) The image density was poor.

Example 2: Same cylindrical shape A as Comparative Example 2! Aluminum-5 on the board
A solution consisting of 1 part by weight of eC-butoxide and 40 parts by weight of ethyl alcohol was applied by dip coating and dried and cured in an oven at 250°C for 2 hours to provide an intermediate layer with a thickness of 0.2 μm. next,
Comparative Example 2 was applied onto this intermediate layer by the same method as Comparative Example 2.
A photoconductive layer mainly composed of amorphous silicon with the same content as Comparative Example 2! The film thickness was approximately the same. When the photoreceptor obtained in this way was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image of 613, which had no practical problems at the initial stage, was obtained.
degree was obtained. In addition, despite repeated copying attempts 50,000 times, no decrease in image density was observed.

Comparative Example 3: A cylindrical Aβ substrate was installed at a predetermined position in the reaction chamber of a capacitively coupled plasma CVD apparatus, the substrate temperature was maintained at a predetermined temperature of 250°C, and 100% silane (Si) was placed in the reaction chamber.
)(,)Gas 1000p of cumulative dilution with 12QCC1 water per minute
pm Jibora: / (B21-16) force 30c per minute
c. 100% acidic (02) gas was introduced at a rate of 1.0cc per minute, and 100% water (H2) gas was introduced at a rate of 89cc/min, and the internal pressure in the reaction tank was maintained at 0.5 Torr. After that, a high frequency power of 13.56 M, Hz was applied to generate a glow discharge, and the output of the high frequency power source was maintained at 85 W. In this way, a cylindrical AA substrate with a thickness of 2
A photoreceptor was obtained having a photoconductive layer having a thickness of 5 μm and consisting of a P-type semiconductor mainly composed of amorphous silicon and containing boron atoms and carbon atoms as impurities. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density sufficient for practical use was not obtained.

Example 3: A solution consisting of 1 part by weight of aluminum-5ec-butoxide, 1 part by weight of methyltrimethoxysilane, 30 parts by weight of isopropyl alcohol, and 30 parts by weight of ethyl alcohol was applied by dip coating to the same cylindrical Afl substrate as in Comparative Example 3. death,
Dry smoke curing was performed in an oven at 250° C. for 2 hours to provide a 0.2 μm thick intermediate layer. Next, on this intermediate layer, by the same method as in Comparative Example 3, a photoconductive layer mainly composed of amorphous silicon having the same contents as in Comparative Example 3 was provided with approximately the same thickness as in Comparative Example 3. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. In addition, although copying and drying was repeated 50,000 times, the image density decreased (unreadable).

Effects of the Invention The electrophotographic photoreceptor of the present invention maintains the excellent properties of photoreceptors made of amorphous silicon, such as high mechanical strength, high durability, high heat resistance, and high photosensitivity. It has a high charge retention ability and can provide high-quality images regardless of the period or number of uses.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising an intermediate layer and a photoconductive layer sequentially laminated on a conductive substrate, wherein the photoconductive layer is mainly composed of amorphous silicon containing hydrogen atoms as an impurity. The intermediate layer is made of a P-type semiconductor containing a boron atom, and further contains at least one type of carbon atom, nitrogen atom, or oxygen atom, and the intermediate layer contains at least one organic aluminum compound.
1. A photoreceptor for electrophotography, characterized in that it is made of a dried and cured product of a solution containing various types of photoreceptors.