JPS62145252A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having a very small dark decay of the electrostatic potential by providing an intermediate layer between the electroconductive substrate and the photoconductive layer composed of a non- crystalline silicon, and by incorporating a dry cured material of a solution contg. an org. stannic compd. to the intermediate layer. CONSTITUTION:The photoconductive layer is composed of an i-type semiconductor having the non-crystalline silicon contg. hydrogen atom, as a main component. and at least one kind of a carbon atom, a nitrogen atom or an oxygen atom. The intermediate layer is composed of the dry cured material of the solution contg. the org. stannic compd. As the used org. stannic compd, stannic bisacetylacetonate, etc is examplified. The dry curing temp. of said compd. is 100-400 deg.C. The thickness of the film of the surface layer is preferable to be <=1mum.

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,
Transfer the toner image to transfer paper and fix it.

This method is used to obtain copies. 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, etc.
Organic photosensitive materials such as phthalocyanine, pyrazoline, and hydrazone are known, and are used as a single layer or a stack of photosensitive layers. However, these conventionally used photosensitive layers have problems that still need 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 has an amorphous film of silicon formed on a conductive substrate using silane (SiH2) gas using a glow discharge decomposition method. Hydrogen atoms are incorporated 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 depending on the influence of environmental conditions, and in particular, the charging potential decreases significantly in a high temperature and high humidity environment.

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 can be 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 tin compound as the intermediate layer. I found it. The photoconductive layer is an l-type semiconductor mainly composed of amorphous silicon,
Further, a material containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms is used.

Thus, according to the present invention, in an electrophotographic photoreceptor in which an intermediate layer and a photoconductive layer are sequentially laminated on a conductive substrate, the photoconductive layer is mainly made of amorphous silicon containing hydrogen atoms. The intermediate layer further contains at least one of carbon atoms, nitrogen atoms, and acid atoms, and the intermediate layer contains at least one organic tin compound.
Provided is an electrophotographic photoreceptor characterized by being made of a dried and cured product of a solution containing various types of electrophotographic photoreceptors.

Examples of the organic tin compound used to form the intermediate layer of the electrophotographic photoreceptor of the present invention include tin bisacetylacetonate, tin tetramethoxide, tin tetraethoxide, tin tetraisopropoxide, and tin tetrabutoxide. , tin tetra-3ec-butoxy, and the like.

In order to obtain the electrophotographic photoreceptor of the present invention, a solution of one or more of the above-mentioned organic tin compounds dissolved in a suitable solvent is coated. Further, at this time, a solution in which an organosilicon compound is mixed with these organotin compounds may be used. Compounds generally called silane coupling agents are suitable as the organosilicon compound, such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane,
γ-glycidoxypropyltrimethoxysilane, T-methacryloxypropyltrimethoxysilane, N-β(
(aminoethyl)r-aminopropyltrimethoxysilane, N-β(aminoethyl)T-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, T-mercaptopropyltrimethoxysilane, T-
Examples include aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldi, °toxysilane, 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 organotin compound and optionally an organosilicon compound is applied onto the photoconductive layer by methods such as spray coating, dip coating, knife coating or roll coating, followed by drying and curing. An electrophotographic photoreceptor of the invention is obtained. Dry curing temperature is 100~
Any temperature between 400°C can be set.

Although the thickness of the surface layer finally obtained can be set arbitrarily, it is preferably 0.1 to 10 μm, particularly 1 μm or less.

The photoconductive layer mainly composed of amorphous silicon is S i II
4.5i21(,,5izl(a, Si+[(+o), etc., or a mixture thereof, can be used as a raw material for the glow discharge method, sputtering method, ion blating method, vacuum evaporation method, etc. It is formed on a substrate by a plasma CVD (Chemical CVD) method.
A method (glow discharge method) in which silane (SiH, ) gas or the like is decomposed by glow discharge using a vapor deposition 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.

In addition, in this photoconductive layer mainly composed of amorphous silicon,
In order to make the layer more of a type 1 semiconductor, a trace amount of boron 1 (B
) can be added. For this addition of boron atoms, boron (B2Ha) gas is usually used as a raw material.

In this case, the amount of boron atoms added is about 10 to 1100 pp.

Further, in the electrophotographic photoreceptor according to the present invention, the photoconductive layer is made of an l-type semiconductor mainly composed of amorphous silicon containing hydrogen atoms, and further includes at least one of carbon atoms, nitrogen atoms, and oxygen atoms. Contains one type. The inclusion of such atoms is particularly preferable from the viewpoint of increasing the dark resistance of the photosensitive layer, increasing the photosensitivity, and further increasing the charging ability (charging potential per unit film thickness).

Furthermore, it is also possible to add an element such as germanium (6c) to the photoconductive layer film for the purpose of increasing the sensitivity of the photoreceptor in the long wavelength region. 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 performed 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 degree of vacuum during discharge is O,l ~5 Torr, substrate heating temperature 100~40
It is 0°C. Therefore, the thickness of the photoconductive layer mainly composed of amorphous silicon is preferably 1 to 100 .mu.m, particularly 10 to 50 .mu.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 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,) gas per minute at 120cc100pp of hydrogen dilution
m diborane (B2H6) gas at 20CG/min, 100
% ethylene (C2)1. ) Gas was introduced at 12 cc per minute, and 100% hydrogen (B2) gas was introduced at a rate of 880 C per minute, and the internal pressure inside the reaction tank was maintained 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, a thickness of 25 μm was placed on a cylindrical AI substrate.
A photoreceptor having a photoconductive layer made of a type 1 semiconductor mainly composed of amorphous silicon and containing carbon atoms as an impurity was obtained.

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 density that was acceptable for practical use was initially obtained, but as copying operations were repeated, it gradually deteriorated. The image density decreased.

Example 1: A solution consisting of 1 part by weight of tin tris acetylacetonate, 1 part by weight of methyltrinatoxysilane, 20 parts by weight of methyl alcohol, and 30 parts by weight of isopropyl alcohol was applied by dip coating to the same cylindrical Atl substrate as in Comparative Example 1. 25
It was dry-hardened in an oven at 0° 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 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. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed. At the same time, copying tests conducted using the negative corona charging method also gave good results, similar to those using the positive charging method.

Comparative Example 2: A substrate was installed in a cylindrical shape 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 (Si) was placed in the reaction chamber.
H4) gas at 12 Qcc per minute.

Hydrogen diluted 100ppm diborane (B, H,) gas at 20cc/min, 100% nitrogen (N2) gas at 85cc/min
c. Furthermore, 100% hydrogen (B2) gas was introduced at a rate of 15 cc per minute to maintain an internal pressure of Q, 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, a photoreceptor was obtained having a photoconductive layer having a thickness of 25 μm and consisting of an l-type semiconductor mainly composed of amorphous silicon and containing nitrogen atoms as impurities on a cylindrical Aβ substrate. The photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method.
At the initial stage, a practically acceptable image density was obtained, but as copying operations were repeated, the image density gradually decreased.

Example 2: On the same cylindrical/l substrate as in Comparative Example 2, 2 parts by weight of tin tetraisopropoxy, 1 part by weight of dimethylcytoxysilane,
A solution consisting of 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 0.3 μm thick. Next, on this intermediate layer, by the same method as in Comparative Example 2, a photoconductive layer mainly composed of amorphous silicon having the same contents as in Comparative Example 2 was provided with approximately the same thickness as in Comparative Example 2.

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. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed. At the same time, copying tests conducted using the negative corona charging method also gave good results, similar to those using the positive charging method.

Comparative Example 3: A cylindrical/1 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 diluted 100ppm diborane (B21(6) gas at 20cc/min. 1100% oxygen (02) gas at 1.0cc/min.
0cc, and 100% hydrogen (B2) gas at 99c/min
After maintaining the internal pressure in the reaction tank at 0.5 Torr, a high frequency power of 13.56 MHz was applied to generate a glow discharge, and the output of the high frequency power supply was increased to 85 W by 1.5 Torr. I have an IF. In this way, the cylindrical Δ
A photoreceptor was obtained having a photoconductive layer having a thickness of 25 μm and consisting of an l-type semiconductor mainly composed of amorphous silicon and containing carbon atoms as impurities on a β substrate. 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, the image density was found to be i, which was acceptable for practical use at the initial stage, but as copying operations were repeated, The image source gradually decreased once.

Example 3: 2 parts by weight of tin tetrabutoxide, 1 part by weight of T-acryloxypropyltrimethoxysilane, and 20 m''fL of methyl alcohol were added to the same cylindrical Aβ substrate as in Comparative Example 3.
A solution consisting of 30 mff18'E of ethyl alcohol was applied by dip coating, dried and cured in an oven at 250°C for 2 hours,
A 0.2 μm thick intermediate layer was provided. 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, it was found that the image density at the initial stage was not a problem for practical use. No decrease in image density was observed even after repeating this process 10,000 times.At the same time, copying tests conducted using the negative corona charging method also gave good results, similar to those using the positive charging method.

Effects of the Invention The electrophotographic photoreceptor of the present invention retains the excellent properties of a photoreceptor made of amorphous silicon, such as high mechanical strength, high durability, high heat resistance, and high photosensitivity, and is also resistant to the external environment. It has a high charge retention ability and can provide images of excellent quality without being affected by the 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 made of amorphous silicon containing hydrogen atoms. type semiconductor, further containing at least one type of carbon atom, nitrogen atom, or oxygen atom, and characterized in that the intermediate layer is made of a dried and cured product of a solution containing at least one type of organic tin compound. A photoreceptor for electrophotography.