JPS62273557A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having a very small dark attenuation of the electrostatic charge potential by constituting a photoconductive layer from an n-type semiconductor which contains an amorphous silicon contg. hydrogen atom as a main component, and phosphorous atom as an impurity, and by constituting a surface layer from a dried curing material of a solution contg. at least one kind of an org. stannic compd. CONSTITUTION:The photoconductive layer composed of the amorphous silicon is coated on a conductive substrate, and the surface layer is laminated on the photoconductive layer. The dried curing material of the solution contg. at least one kind of the org. stannic compd. is used as the surface layer. The n-type semiconductor comprising the amorphous silicon as the main component, and phosphorous atom as the impurity is used as the photoconductive layer. The further preferable org. stannic compd. is a stannic complex and a stannic alkoxide. At the time of obtaining the titled body, one or >=2 kinds of the org. stannic compds. are dissolved a suitable solvent, and the obtd. solution is coated on the substrate. Thus, the high mechanical strength, the high durability, the high heat-resisting property and the high photosensitivity of the titled body are maintained, and the high electric charge holding power of the titled body is obtd., without being affected by the surroundings of an outside and the number of using, thereby obtaining the picture image having excellent quality.

Description

3. Detailed Description of the Invention Field of Industrial Application The present invention relates to an electrophotographic photoreceptor, and particularly to an electrophotographic photoreceptor using amorphous silicon in the photosensitive layer.

Conventional technology Electrophotography involves charging a photoreceptor and forming an electrostatic latent image by exposing it to light. After developing this latent image with a developer, the toner image is transferred to transfer paper and fixed to obtain a copy. The photoreceptor used in this electrophotographic method basically consists of a photosensitive layer laminated on a conductive substrate.
Conventionally, inorganic photosensitive materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide have been used as materials constituting photoreceptors. Alternatively, organic photosensitive materials such as polyvinylcarbazole, trinitrofluorenone, bisazo pigments, phthalocyanine, pyrazoline, and hydrazone 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 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 coated a photoconductive layer made of amorphous silicon on a conductive substrate, further laminated a surface layer thereon, and as the surface layer. It has been found that the above object can be achieved by using a dried and cured product of a solution containing at least one type of organic tin compound. As the photoconductive layer, an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus atoms as an impurity is used.

Thus, according to the present invention, in an electrophotographic photoreceptor in which a photoconductive layer and a surface layer are sequentially laminated on a conductive substrate, the photoconductive layer is mainly made of amorphous silicon containing hydrogen atoms. It is made of an n-type semiconductor containing phosphorus atoms as impurities, and further does not contain at least one type of nitrogen atom, carbon atom, or oxygen atom, and the surface layer contains at least one type of organic tin (Sn) compound. An electrophotographic photoreceptor is provided that is made of a dried and cured product of a solution.

Although various organic tin compounds can be used to form the surface layer of the electrophotographic photoreceptor of the present invention, tin complexes and tin alkoxides are particularly preferred. Preferred examples of these include tin bisacetylacetonate, tin tetramethoxide, tin tetraethoxide, tin tetraisopropoxide, tin tetraethoxide, and tin tetra-5ec-butoxide.

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, γ-methacryloxypropyltrimethoxysilane, N-β(
(aminoethyl) T-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, T-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, r-
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 cuff pulling agent accounts 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 final surface layer can be set arbitrarily,
0.1 to 10 μm is suitable.

The photoconductive layer mainly composed of amorphous silicon is 5IH4,5i
It is formed on a substrate by a method such as a glow discharge method, a sputtering method, an ion blasting method, or a vacuum evaporation method using one type of hydrogen silicon gas such as 2Hs, 513Ha, 3i4H+o, or a mixture thereof as a raw material. Among them, plasma CVD (Chemical Vapor D)
Silane (S+H,
) A method of decomposing gas etc. 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.

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, and amorphous silicon, which is an n-type semiconductor, is obtained by adding 0.01 to 1003 ppm of phosphorus atoms.

Further, the electrophotographic photoreceptor according to the present invention further contains at least one type of carbon atom, nitrogen atom, or oxygen atom. 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).

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 range. Furthermore, by adding atomic atoms, the dark resistance can be increased.

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 0.1 to 5 Torr, and the substrate heating temperature is lOO~
The temperature is 400°C. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon is 1 to 100 μm, especially 10 to 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 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 t, and 100% silane (S) was placed in the reaction chamber.
IH4) Gas at 120cc per minute.

Hydrogen diluted 300ppm phosphine (PH,) gas was introduced at a rate of 30cc/min, 100% ethylene (C2H-) gas at a rate of 15cc/min, and 100% hydrogen (H2) gas was introduced at a rate of 75cc/min into the reaction tank. 0.5To
After maintaining the internal pressure at rr, high-frequency power of 13.56 MHz was applied to generate glow discharge, and the output of high-frequency power 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 phosphorus and carbon atoms as impurities on a cylindrical AI 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 that could withstand practical use was not obtained. In addition, this photoreceptor was
When image quality was evaluated under an environment of 0° C. and 85% RH, image flow was observed.

Example 1: On a photoreceptor having a photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus and carbon, which was produced by the same method and under the same conditions as Comparative Example 1, tin bisacetylacetate was applied. A solution consisting of 1 part by weight of Nate, 1 part by weight of methyltrimethoxysilane, 20 parts by weight of methyl alcohol, and 30 parts by weight of isopropyl alcohol was applied by dip coating, and the solution was heated at 200°C.
The photoreceptor was dried and cured for 1 hour in an oven to obtain a photoreceptor having a surface layer with a thickness of 0.2 μm. The obtained surface layer had properties similar to ceramics, and the excellent properties of amorphous silicon, such as surface hardness, wear resistance, and heat resistance, were hardly impaired.

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 image quality of this photoreceptor was evaluated under an environment of 30° C. and 85% RH, but no image flow was observed, indicating high resolution.

Comparative Example 2: A cylindrical A1 was installed at a predetermined position in the reaction chamber of a capacitively coupled plasma CVD apparatus, the substrate temperature was maintained at the predetermined temperature of 250°C, and 100% non-run (S) was carried out in the reaction chamber.
iH,) 300pp of gas diluted with 120CC1 hydrogen per minute
m phosphine (Pi(3) gas at 30 cc/min and 100% hydrogen (H2) gas at 90 cc/min, and 1
After introducing 00% hydrogen (H2) gas at a rate of 1 Qcc per minute and maintaining an internal pressure of Q and 5 Torr in the reaction tank, 13.5
High frequency power of 6 MHz was applied to generate glow discharge, and the output of the high frequency power source was maintained at 8.5 W. In this way, a photoreceptor was obtained on a cylindrical AI substrate, 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 and nitrogen as impurities.

When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a negative corona charging method, it was found that an image density that was acceptable for practical use could not be obtained.

Further, when the image quality of this photoreceptor was evaluated in an environment of 30° C. and 85% RH, flow of one image was observed.

Example 2: Tin tetrine propoxide was applied onto a photoreceptor having a photoconductive layer made of a p-type semiconductor mainly composed of amorphous silicon and containing phosphorus, which was produced by the same method and under the same conditions as Comparative Example 2. A solution consisting of 2 parts by weight of dimethyldimethoxysilane, 1 part by weight of dimethyldimethoxysilane, and 40 parts by weight of ethyl alcohol was applied by dip coating, and dried and cured at 200° C. for 1 hour to obtain a photoreceptor having a surface layer with a thickness of 0.3 μm. The treated surface layer had properties similar to ceramics, and the excellent properties of amorphous silicon, such as surface hardness, wear resistance, and heat resistance, were hardly impaired.

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. Although the copying operation was repeated 50,000 times, no decrease in image density was observed. This photoreceptor was evaluated for image quality in an environment of 30°C and 85% RH, but no image bleeding was observed. It showed high resolution.

Comparative Example 3: A cylindrical Al 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.
H4) gas at 12 Qcc per minute.

Hydrogen diluted 100 ppm phosphine (PH3) gas was introduced at 33 cc per minute, 100% oxygen (02) gas was introduced at 1, Qcc per minute, and 100% hydrogen (H2) gas was introduced at 39 cc per minute into the reaction tank. After maintaining Q at an internal pressure of 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 85 W. 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 and oxygen as impurities, on a cylindrical β 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 that could withstand practical use was not obtained.

Further, when the image quality of this photoreceptor was evaluated in an environment of 30° C. and 85% RH, image smearing was observed.

Example 3: On a photoreceptor having a photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus and oxygen as impurities, which was prepared by the same method and under the same conditions as Comparative Example 3, tin tetra A solution consisting of 2 parts by weight of butoxide, 1 part by weight of γ-acryloxypropyltrimethoxysilane, 20 parts by weight of methyl alcohol, and 30 parts by weight of ethyl alcohol was applied by dip coating, dried and cured at 200° C. for 1 hour, and 0.05% by weight was applied. 2μ
A photoreceptor having a surface layer with a thickness of m was obtained. The obtained surface layer had properties similar to ceramics, and the excellent properties of amorphous silicon, such as surface hardness, wear resistance, and heat resistance, were hardly impaired.

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 image quality of this photoreceptor was evaluated under an environment of 30° C. and 85% RH, but no image flow was observed, indicating high resolution.

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 regardless of the number of uses.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photoconductive layer and a surface layer sequentially laminated on a conductive substrate, wherein the photoconductive layer is mainly composed of amorphous silicon containing hydrogen atoms and contains impurities. A dry cured product of a solution consisting of an n-type semiconductor containing phosphorus atoms, further containing at least one type of carbon atom, nitrogen atom, or oxygen atom, and the surface layer containing at least one type of organic tin compound. An electrophotographic photoreceptor comprising: