JPS62145249A - 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 a semiconductor having the non-crystalline silicon contg. hydrogen atom, as a main component. 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 solution of the org. stannic compd, optionally, adding the org. silicon comd, is coated on the photoconductive layer by means of a various kinds of the coating method such as a spray coating, a dipping coating, a knife coating or a roll coating, followed by drying and curing it. 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] ZtU 1 crime 1 stand! 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 photoreceptors have been inorganic photosensitive materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide, or organic photosensitive materials such as polyvinylcarbazole, trinitrofluorenone, bisazo pigments, phthalocyanine, pyrazoline, and hydrazone. 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 made by forming an amorphous film of silicon on a conductive substrate using silane (SiH4) 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 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 inventor of the present invention has provided an intermediate layer between a conductive substrate and a photoconductive layer made of amorphous silicon, and has provided an intermediate layer containing at least one type of organic tin compound as the intermediate layer. It has been found that the above object can be achieved by using a dry and cured product of the solution containing the present invention. As the photoconductive layer, a semiconductor mainly composed of amorphous silicon is used.

Thus, according to the present invention, there is provided an electrophotographic photoreceptor in which an intermediate layer and a photoconductive layer are sequentially laminated on a conductive substrate, and the photoconductive layer is made of amorphous silicon containing hydrogen atoms. There is provided an electrophotographic photoreceptor which is mainly made of a semiconductor, and wherein the intermediate layer is made of a dried and cured product of a solution containing at least one organic tin compound.

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 tetrapropoxide, and tin tetrabutoxide. Examples include side, tin ester, 3ec-butoxide, 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,
T-glycidoxypropyltrimethoxysilane, T-methacryloxypropyltrimethoxysilane, N-β(
Aminoethyl) T-aminopropyltrimethoxysilane, N-β(amineethyl)γ-aminopropylmethyldimethoxysilane, T-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, T-
Examples include aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxylane, 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.

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 Sin, 51
2H6, 513H1l, Si<H+. , etc. or a mixture thereof as a raw material, glow discharge method, sputtering method, ion blating method,
It is formed on a substrate by a method such as a vacuum evaporation method. Among them, plasma CVD (Che+n1cal Vapor
Silane (Si
A method of decomposing H<) gas and the like by glow discharge (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.

In addition, diborane (B, H,
, ) gas or phosphine (PH3) gas to add an impurity element such as boron (B) or phosphorus (P) into the photoconductive layer.

Further, in the electrophotographic photoreceptor according to the present invention, the photoconductive layer is made of a semiconductor mainly composed of amorphous silicon containing hydrogen atoms, and further includes at least one of carbon atoms, nitrogen atoms, and oxygen atoms. types may be included. The inclusion of such atoms increases the dark resistance of the photosensitive layer, and
This is preferable from the viewpoint of increasing photosensitivity and further increasing charging ability (charging potential per unit film).

Furthermore, it is also possible to add an element such as germanium (Ge) to the photoconductive layer 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 33 MHz, and the degree of vacuum during discharge is 0.1-5 Torr, substrate heating temperature 100-400℃
It is. 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.

[Example 11] 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 Aβ 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 (Si) was placed in the reaction chamber.
H,) gas at 120 CG per minute.

100ppm diborane (B2H6) gas diluted with hydrogen was introduced at 2 Qcc per minute, and 100% hydrogen (H2) gas was introduced at a rate of 9 Qcc per minute, and the inside of the reaction tank was heated to Q, 5 Torr.
After maintaining the internal pressure at , 13.56 MHz high frequency power was applied to generate glow discharge, and the output of the high frequency power source was maintained at 85 W. In this way, a so-called lubricant with a thickness of 25 μm and mainly composed of amorphous silicon and containing hydrogen atoms and trace amounts of boron atoms as impurities was deposited on a cylindrical Al substrate.
A photoreceptor having a photoconductive layer made of a type semiconductor 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 discharge method, an image density that was acceptable for practical use was initially obtained, but as copying operations were repeated, the image quality gradually deteriorated. The image density decreased.

Example 1: A solution consisting of 1 part by weight of tin bisacetylacetonate, 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 A1 substrate as in Comparative Example 1. and 250℃
The mixture was dried and cured for 2 hours in an oven to provide 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 cylindrical AI 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) 120cc of gas per minute.

500 ppm diborane (B2H6) gas diluted with hydrogen was introduced at a rate of 30 cc per minute, and 100% hydrogen (H2) gas was introduced at a rate of 80 cc per minute, and the inside of the reaction tank was maintained at Q, 5 Torr.
After maintaining the internal pressure at , 13.56 MHz high frequency power was applied to generate glow discharge, and the output of the high frequency power source was maintained at 85 W. In this way, a photoreceptor was obtained having a photoconductive layer having a thickness of 25 μm and consisting of a p-type semiconductor mainly composed of amorphous silicon and containing hydrogen atoms and boron atoms as impurities on a cylindrical Al substrate. 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 2: A solution consisting of 2 parts by weight of tintetraisopropoxy, 1 part by weight of dimethyldimethoxysilane, and 40 parts by weight of ethyl alcohol was applied onto one cylindrical substrate in the same cylindrical shape as in Comparative Example 2 by dip coating, and the solution was placed in an oven at 250°C. After drying and curing for 2 hours, an intermediate layer having a thickness of 0.3 μm was provided. 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. Also, the copy operation is
Although the process was repeated 10,000 times, no decrease in image density was observed.

Comparative Example 3: 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.
H,) gas at 120cc/min, 300ppm diluted with hydrogen
39cc of phosphine (PH,) gas per minute, and 1
00% hydrogen (H2) gas was introduced at a rate of 80 cc per minute, and the internal pressure inside the reaction tank was maintained at 0.5 Torr.
High frequency power of 3.56 MHz was applied to generate glow discharge, and the output of the high frequency power source was maintained at 85W. In this way, a 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 hydrogen atoms and phosphorus atoms as impurities on a cylindrical Al substrate. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona charging method, there was no difference in image density that could be used for practical use.

Example 3: A solution consisting of 2 parts by weight of tin tetrabutoxide, 1 part by weight of T-acryloxypropyltrimethoxysilane, 20 parts by weight of methyl alcohol, and 30 parts by weight of ethyl alcohol was placed on the same cylindrical Al substrate as in Comparative Example 3. Apply by dipping,
It was 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, 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. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed.

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 a semiconductor mainly composed of amorphous silicon containing hydrogen atoms. An electrophotographic photoreceptor comprising: the intermediate layer comprising a dried and cured product of a solution containing at least one type of organic tin compound.