JPS62144174A - 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 an N type semiconductor contg. amorphous silicon contg. H as the principal component and P 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 a toner,
This is a method of transferring and fixing a toner image onto transfer paper to obtain 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 and optical materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide; Organic photosensitive materials are known,
The photosensitive layer is used as a single layer or as a stack. However, these conventionally used photosensitive layers are
There are still problems to be solved in terms of durability, heat resistance, photosensitivity, etc.

In recent years, photoreceptors using amorphous silicon as the photosensitive layer have been known, and various attempts have been made to improve them. This photoreceptor using amorphous silicon is one in which an amorphous film of silicon is formed on a conductive substrate using silane (SiH) gas using a glow discharge decomposition method. 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 disadvantage that dark decay is large and a sufficient charging potential cannot be obtained even when charged. That is, an amorphous silicon photoreceptor is charged, imagewise exposed to form an electrostatic latent image,
During subsequent development, the surface charge on the photoreceptor will attenuate until the image exposure process or even the charge on the areas that have not been exposed to light during the development process, making it impossible to obtain the charging potential necessary for development. . This attenuation of the charging potential is likely to change due to the influence of environmental conditions, and particularly in high temperature environments, 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 an electrophotographic photoreceptor whose charging characteristics are not affected by changes in 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 discovered that a conductive substrate,
The above object is achieved by providing an intermediate layer between the photoconductive layer and the photoconductive layer made of amorphous silicon, and using a dried and cured product of a solution containing at least one organic aluminum compound as the intermediate layer. I found it. As the photoconductive layer, an N-type semiconductor mainly composed of amorphous silicon and containing phosphorus atoms as impurities is used, which further contains at least one type of carbon atoms, nitrogen atoms, or oxygen atoms. .

Thus, according to the present invention, in an electrophotographic photoreceptor comprising an intermediate layer and a photoconductive layer sequentially laminated on a conductive substrate, the photoconductive layer is mainly made of amorphous silicon containing hydrogen atoms. The intermediate layer is made of an N-type semiconductor containing phosphorus atoms as impurities, and further contains at least one type of carbon atoms, nitrogen atoms, or oxygen atoms, and the intermediate layer
There is provided an electrophotographic photoreceptor characterized by being made of a dried and cured product of a solution containing at least one type of organoaluminum compound.

Examples of organoaluminum compounds 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, and aluminum Mu5ec-butoxide, aluminum-n-
Examples include butoxide.

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. Compounds generally called silane coupling agents are suitable as the organosilicon compound, such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-glycidoxypropyltrimethoxy Silane, r-methacryloxypropyltrimethoxysilane, N-β (aminoethyl) T-aminopropyltrimethoxysilane, N-β (aminoethyl) T-aminopropylmethyldimethoxysilane, T-chloropropyltrimethoxysilane, 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, and then drying and curing. The drying and curing temperature can be set at any temperature between 100 and 400°C. The thickness of the surface layer finally obtained can also be set arbitrarily, but a thickness of 0.1 to 10 .mu.m, particularly 1 .mu.m or less, is suitable.

The photoconductive layer mainly composed of amorphous silicon is S i I+
Using one type of hydrogen silicon gas such as 4.5izHs, 513He, 514H1°, etc. or a mixture thereof as a raw material,
It is formed on a substrate 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 Vap
Silane (S
A method of glow discharge decomposition of iH<) gas, etc. (glow discharge method) is preferable from the viewpoint of controlling the hydrogen content in the film. Further, in this case, in order to more efficiently contain hydrogen, hydrogen (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 an N-type semiconductor mainly composed of amorphous silicon containing hydrogen atoms and containing phosphorus atoms as impurities. For this addition of phosphorus atoms, phosphine (PH3) gas is usually used as a raw material. In this case, the phosphorus atom additive is 0.0
It is about 1 to 1000 ppm.

Further, in the electrophotographic photoreceptor according to the present invention, the photoconductive layer is mainly composed of amorphous silicon containing hydrogen atoms, and is composed of an N-type semiconductor containing phosphorus atoms as impurities, and further contains carbon atoms, nitrogen atoms, etc. Contains only one type of atoms or oxygen atoms.The inclusion of such atoms increases the dark resistance of the photosensitive layer, increases the photosensitivity, and further increases the chargeability (per unit film thickness). This is preferable from the viewpoint of increasing the charging potential).

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, silicon hydride gas, which is the main raw material, and hydrogen gas, if desired, are used in a plasma CVD apparatus, and together with these gases, Glow-discharge decomposition may be carried out by introducing a gaseous compound containing the necessary elements. As mentioned 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 10
The temperature is 0 to 400°C. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon is 1 to 100 μm, especially 10 to 5 μm.
It is preferable to set it to 0 μm.

Conductive (Ki) As the substrate, metals such as aluminum, nickel, chromium, stainless steel, or brass, plastic sheets or glass with a conductive film, or paper treated with conductivity can be used. The shape of the substrate can be any shape, such as a cylinder, a flat plate, or an endless belt.

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 Affi 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 (
SiH,) gas per minute at 300p with 120CC1 hydrogen dilution
pm Phosphine (PH3) gas 30ccSLQ per minute
O% ethylene (C2H,) gas per minute 15c5 more 1
After introducing 00% hydrogen (N2) gas at a rate of 75 cc per minute and maintaining the internal pressure in the reaction tank at Q, 5 Torr,
High frequency power of 13.56 MHz was applied to generate glow discharge, and the output of the high frequency power source was maintained at 85W. In this way, to a cylindrical shape! 25μ thick on the board
A photoreceptor having a photoconductive layer made of an N-type semiconductor mainly composed of amorphous silicon and containing phosphorus atoms and carbon atoms as impurities was obtained. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a negative corona charging method, an image density sufficient for practical use was not obtained.

Example 1: A solution consisting of 1 part by weight of aluminum trisacetylacetonate and 30 parts by weight of isopropyl alcohol was dip coated onto the same cylindrical/1/2 substrate as in Comparative Example 1, and
It was dried and cured in an oven at 0.degree. C. for 2 hours to provide a 0.1 .mu.m thick intermediate layer. 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 negative corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed.

Comparative Example 2: A cylindrical Afl 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 (S) was placed in the reaction chamber.
iH,) 120cc of gas per minute.

Hydrogen dilution of 300ppm phosphine (PH3) gas at 33cc/min, 100% nitrogen (N2) gas at 90cc/min
c. Furthermore, 100% hydrogen (N2) gas was introduced at a rate of 10 cc per minute to maintain an internal pressure of 0.5 Torr in the reaction tank, and then 13.56 MHz high-frequency power was applied to generate glow discharge. The output of the high frequency power supply is 85
I kept it at W. In this way, the cylindrical A, Il! A photoreceptor having a photoconductive layer on a substrate with a thickness of 25 μm and consisting of an N-type semiconductor mainly composed of amorphous silicon and containing phosphorus atoms and nitrogen atoms as impurities is rated as 1st class. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a negative corona charging method, an image density sufficient for practical use was not obtained.

Example 2: Aluminum-5 was applied to the same cylindrical Δβ substrate as in Comparative Example 2.
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 having the same content as that of Comparative Example 2 was provided with approximately the same thickness as Comparative Example 2. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a negative corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed.

Comparative Example 3: A cylindrical A1 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.
H,) gas at 12 Qcc per minute.

Hydrogen dilution of 300ppm phosphine (PH3) gas at 300C/min, 100% acid accumulation (0□) gas at 1.0%/min
cc, and 89cc of 100% hydrogen (N2) gas per minute.
After maintaining the internal pressure in the reaction tank at 0.5 Torr, high frequency power of 13.56 MHz was applied to generate glow discharge, and the output of the high frequency power supply was increased to 8 Torr.
It was maintained at 5W. In this way, a photoreceptor was obtained having a photoconductive layer having a thickness of 25 μm and consisting of an N-type semiconductor mainly composed of amorphous silicon and containing phosphorus atoms and carbon atoms as impurities on a cylindrical Aβ substrate. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a negative 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 A42 substrate as in Comparative Example 3. death,
Slow drying and curing was performed in an oven at 250° C. for 2 hours to form an intermediate layer with a thickness of 0.2 μm. 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 negative corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed.

The electrophotographic photoreceptor of the present invention maintains the excellent properties of a photoreceptor made of amorphous silicon, such as high mechanical strength, high durability, high heat resistance, and high photosensitivity. , it has a high charge retention ability without being affected by the external environment or the number of times of use, and can provide images of excellent quality.

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 an N-type semiconductor containing a phosphorus 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.