JPS62273558A - 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 a p-type semiconductor which contains an amorphous silicon contg. hydrogen atom as a main component, and boron 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 p-type semiconductor comprising the amorphous silicon as the main component, and boron 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 electrophotography is a method in which an electrostatic latent image is formed by charging a photoreceptor and image exposure, and after developing this latent image with a developer, the toner image is transferred and fixed onto a transfer paper to obtain a copy. Are known. The photoreceptor used in this electrophotographic method basically has a photosensitive layer laminated on a conductive substrate. Conventionally, the materials constituting the photosensitive layer 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, and are used with 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 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 cloud surroundings of 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 1!1 types of organic tin compounds. The photoconductive layer is mainly made of amorphous silicon,
A p-type semiconductor containing boron 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. The surface layer is made of a p-type semiconductor containing phosphorus atoms as impurities, and further contains at least 11 endogenous carbon atoms, nitrogen atoms, or oxygen atoms, and the surface layer contains at least one type of organic tin (Sn) compound. Provided is an electrophotographic photoreceptor comprising a dried and cured product of a solution containing:

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 tetrabutoxide, 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,
γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β(
Aminoethyl>T-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
Examples include aminepropyltriethoxysilane, 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. Although the final thickness of the surface layer 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 SiH, 5I
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 2H6, S +3Hs, Si<H+o, or a mixture thereof as a raw material. .

Among them, plasma CVD (Chemical Vapo
sila (SiH) by the
,) Method of decomposing gas etc. by glow discharge (glow discharge method)
is preferable from the viewpoint of controlling the hydrogen content in the film. 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 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 (B2Hs) gas is usually used as a raw material, and by adding 0.011 atomic % of boron atoms, 1 amorphous silicon, which is a p-type semiconductor, is provided.

Furthermore, in the electrophotographic photoreceptor according to the present invention, the photoconductive layer further contains at least one of carbon atoms, nitrogen atoms, and oxygen atoms. 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. 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 alternating current discharge, the frequency is usually 0.1 to 3. OMHz, degree of vacuum during discharge is Q, l~5 Torr, substrate heating temperature is 100~4
It is 00℃. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon is 1 to 100 μm, particularly 10 to 50 μm.
It is preferable that

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 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 per minute at 120cc1000pp of hydrogen dilution
m Shiboraf CB2 H6) gas at 30cc/min, 1
00% 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, the cylindrical AI! Thickness 2 on the board
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 image quality was evaluated using a positive 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 a p-type semiconductor mainly composed of amorphous silicon and containing boron and carbon as impurities, which was produced by the same method and under the same conditions as Comparative Example 1, tin bis was applied. A solution consisting of 1 part by weight of acetylacetonate, 1 part by weight of methyltrimethoxysilane, 20 parts by weight of methyl alcohol, and 30 parts by weight of inpropyl alcohol was applied by dip coating, and dried and cured in an oven at 250°C for 2 hours to give a 0.2μ A thick intermediate layer was formed. 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 contents as in Comparative Example 1 was provided with approximately the same thickness as in Comparative Example 1.

When the thus obtained photoreceptor was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density that was satisfactory for practical use was obtained at the initial stage.

Further, although the copying operation was repeated 50,000 times, no decrease in image fi by 1 degree was observed. This photoreceptor was heated at 30°C and 85%RH.
Image quality was evaluated under the following environment, but no image flow was observed, indicating high resolution.

Comparative Example 2: A β 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 12 Qcc per minute.

1000ppm of hydrogen dilution Sibolaf (B2 H1+
) gas at 30cc per minute, and 100% nitrogen (N2)
Gas was introduced at 90cc per minute, and 100% hydrogen (H2) gas was introduced at IQcc per minute, and the inside of the reaction tank was maintained at 0.5 Torr.
After maintaining the internal pressure of 13.56 MHz, a 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 Af
A photoreceptor was obtained having a photoconductive layer on a substrate having a thickness of 25 μm and consisting of a p-type semiconductor mainly composed of amorphous silicon and containing boron and nitrogen 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 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 2: Tin tetrapropoxide was deposited on a photoreceptor having a photoconductive layer made of a p-type semiconductor mainly composed of amorphous silicon and containing boron and nitrogen, which was produced by the same method and under the same conditions as Comparative Example 2. A solution consisting of 2 parts by weight, 1 part by weight of dimethyldimethoxysilane, and 40 parts by weight of ethyl alcohol was applied by dip coating, and dried and cured at 250° C. for 2 hours to form an intermediate layer with a thickness of 0.3 μm. 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 content 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, the image density at the initial stage was not a problem for practical use. Also, the copy operation is
Although the test was repeated 10,000 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 3: A cylindrical All-in-one fund 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 per minute with 120CC1 hydrogen dilution lOQOpp
m Siboraf (B2H8) gas per minute 3Qc5 and 1
00% oxygen (02) gas per minute. Occ, 1 more
After introducing 00% hydrogen (H2) gas at a rate of 89 cc per minute and maintaining the internal pressure in the reaction tank at Q, 5 Torr, 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 85W. In this way, a photoreceptor having a photoconductive layer having a thickness of 25 μm and consisting of a p-type semiconductor mainly composed of amorphous silicon and containing boron and oxygen as impurities was formed on a cylindrical Aβ substrate.
etc.

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 could not be 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: Tin tetrabutoxide 2 A solution consisting of parts by weight, T-acryloxypropyltrimethyne silane 1 part II, 20 parts by weight methyl alcohol, and 30 parts by weight of ethyl alcohol was applied by dip coating,
It was dried at 250° C. for 2 hours to form 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 content 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. The image quality of this photoreceptor was evaluated in an environment of 30° C. and 85% RH, but no image flow was observed and a high resolution of 1 quadrant 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 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. The surface layer is made of a p-type semiconductor containing boron atoms, and further contains at least one type of carbon atoms, nitrogen atoms, or oxygen atoms, and the surface layer
An electrophotographic photoreceptor comprising a dried and cured product of a solution containing at least one type of organic tin compound.