JPS62273552A - 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 comprises an amorphous silicon contg. hydrogen atom as a main component, and also contg. boron atom as the impurity and by constituting a surface layer from a dried curing material of a solution contg. at least one kind of an org. titanium compd. CONSTITUTION:The photoconductive layer composed of the amorphous silicon is coated on the conductive substrate. The surface layer is laminated on the photoconductive layer. The dried curing material of the solution contg. at least one kind of the org. titanium compd. is used as the surface layer. The p-type semiconductor which contains the amorphous silicon as the main component, and also contains boron atom and at least one kind of the atom selected from carbon atom, nitrogen atom and oxygen atom as an impurity is used as the photoconductive layer. The org. titanium compd. is further preferably exemplified by a titanium complex and a titanium alkoxide. The preferable example of the titanium compd. is diisopropoxytitanium bis(acetyl acetonate) etc. 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

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

(Prior Art) In electrophotography, 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 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.

(Problems to be Solved by the Invention) 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 particularly in a high temperature and high humidity environment, the charging potential decreases considerably.

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.

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.

(Means and effects for solving the problem) The present inventor:
As a result of intensive research, we found that a photoconductive layer made of amorphous silicon was coated on a conductive substrate, a surface layer was further laminated thereon, and at least one kind of organic titanium compound was used as the surface 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 p-type semiconductor is used which is mainly composed of amorphous silicon and contains as impurities boron atoms and at least one of carbon atoms, nitrogen atoms, and oxygen atoms.

Thus, according to the present invention, in an electrophotographic photoreceptor comprising a photoconductive layer and a surface layer sequentially laminated on a conductive substrate, the photoconductive layer is mainly composed of amorphous silicon containing hydrogen atoms. It is made of a p-type semiconductor containing boron atoms as impurities, and further contains at least one kind of carbon atoms, nitrogen atoms, and oxygen atoms, and the surface layer is made of a solution containing at least one kind of organic titanium compound. Provided is an electrophotographic photoreceptor comprising a dry cured product.

Although various organic titanium compounds can be used to form the surface layer of the electrophotographic photoreceptor of the present invention, complexes and titanium alkoxides are particularly preferred. Preferred examples of organic titanium compounds include:
Diisopropoxy titanium bis(acetylacetonate)
, polytitanium acetylacetonate, bis(acetylacetonate) titanium oxide, titanium tetraethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutoxide, etc. can be mentioned.

In order to obtain the electrophotographic photoreceptor of the present invention, a solution of one or more of the above organic titanium compounds dissolved in a suitable solvent is coated. Further, at this time, a solution in which an organosilicon compound is mixed with these organotitanium compounds may be used. Compounds generally called silane coupling agents are suitable as the organosilicon compound, and examples thereof include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, and r-glycidoxypyltrimethoxysilane. , γ
-methacryloxypropyltrimethoxine run, N-
β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) T-aminopropylmethyldimethoxy7rane, γ-chloropropyltrimethoxysilane, T-mercaptopropyltrimethoxysilane,
Examples include T-aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, triethylmonomethoxysilane, 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 organozirconium 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 5ifl 5i
Using one type of hydrogen silicon gas such as 2Hs, 5i3H, Si<H+o1, or a mixture thereof as a raw material, a glow discharge method, a sputtering method, an ion blating method,
It is formed on a substrate using a vacuum evaporation method or the like. Among them, Plug 7 CV D (Chemical Vapor D
silane (SiH,) by eposition method
The method of decomposing gas etc. by glow discharge (glow discharge method) is
It 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 (B2H6) gas is usually used as a raw material, and amorphous silicon, which is a p-type semiconductor, can be obtained by adding about 0.011 atomic percent.

Further, 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 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 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 μm, particularly 10 to 50 μm.

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) Next, the electrophotographic photoreceptor of the present invention will be further described with reference to comparative examples and examples of the present invention.

Comparative Example 1: A cylindrical Af substrate was installed at a predetermined position in the reaction chamber of a capacitively coupled plasma CVD apparatus, and the substrate temperature was maintained at a predetermined temperature of 250°C.
i H,) gas at 120 cc/min, hydrogen dilution t O
Oppm diborane (B2H6) gas 20CC1 per minute
and 100% ethyl L/7 (C2H4) gas at 1 min.
5cc, plus 100% hydrogen (N2) gas at 75c/min
After maintaining the internal pressure in the reaction tank at Q and 5 Torr, 13.56 MHz alternating frequency power was applied to generate a glow discharge, and the output of the high frequency power supply was increased to 85 W.
maintained. 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 further containing boron and carbon 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 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 1: On a photoreceptor having a photoconductive layer made of a p-type semiconductor mainly composed of amorphous silicon and containing boron and carbon, which was produced by the same method and under the same conditions as Comparative Example 1, diisopropoxy titanium bis A solution consisting of 1 part by weight (acetylacetonate) and 20 parts by weight of n-butyl alcohol was applied by dip coating,
The photoreceptor was dried and cured at 250° C. for 1 hour to obtain a photoreceptor having a surface layer with a thickness of 0.4 μm. The surface layer thus obtained had properties similar to ceramics, with almost no loss in surface hardness, wear resistance, and heat resistance, which are the excellent properties of amorphous silicon.

When this photoreceptor was placed in a copying machine and the image quality was evaluated using a positive corona charging method, an image density of 1 was given at the initial stage, which was not a problem for practical use. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed. This photoreceptor is 30
Image quality was evaluated under an environment of 85% RH and 85% RH, but no image flow was observed, indicating high resolution.

Comparative Example 2: A cylindrical A1 substrate was installed at a predetermined position in the reaction chamber of a volume-heavy coupled plasma CVD apparatus, the substrate temperature was maintained at a predetermined temperature of 250°C, and 100% silicon 57 (Si) was placed in the reaction chamber.
H4) gas tooppm of 120CC1 hydrogen dilution per minute
Diborane (82H6) gas at 20 CC1 and 1 per minute
00% nitrogen (N2) gas per minute at 9 Qcc, then 10
After flowing 0% hydrogen (N2) gas at a rate of 15 cc per minute and maintaining the internal pressure in the reaction tank at Q, 5 Torr, 13.56
MHz alternating frequency power 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 which had a photoconductive layer on a cylindrical Al substrate with 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.

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

Example 2: Tetraethyl ortho 1 part by weight of titanate, 3 parts by weight of isopropyl alcohol
A solution consisting of 0 parts by weight 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. this.

The surface layer thus obtained had properties similar to ceramics, with almost no loss in surface hardness, wear resistance, and heat resistance, which are the excellent properties of amorphous silicon.

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

Comparative Example 3: 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% unrun (S) was carried out in the reaction chamber.
IH4) 120cc gas per minute, 1000p hydrogen dilution
pm Sibolaf (B2H6) gas at 3 Qcc per minute and 100% oxygen gas at l, Qcc per minute, then 100
% hydrogen (H2) gas was introduced at a rate of 89 cc per minute to maintain an internal pressure of 0.5 Torr in the reaction tank.
MHz alternating frequency power 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 a p-type semiconductor mainly composed of amorphous silicon and containing boron and oxygen 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 positive 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: P made mainly of amorphous silicon and containing boron and oxygen as impurities, prepared by the same method and under the same conditions as Comparative Example 4.
A solution consisting of 1 part by weight of tetrabutyl orthotitanate, 1 part by weight of r-acryloxypropyltrimethoxysilane, 10 parts by weight of methyl alcohol and 20 parts by weight of isopropyl alcohol is applied onto a photoreceptor having a photoconductive layer consisting of a type semiconductor. was coated by dip coating and dried and cured at 250°C for 2 hours to obtain a photoreceptor having a surface layer with a thickness of 0.3 μm.

The surface layer obtained in this way has properties similar to ceramics, and has excellent surface hardness and
There was almost no loss in abrasion resistance and heat resistance.

When this photoreceptor 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 found to be i, which was not a problem for practical use. Further, although the copying operation was repeated 50,000 times, no decrease in image density was observed. This photoreceptor is 30
Image quality was evaluated under an environment of 85% RH and 85% RH, but no image flow was observed, indicating high resolution.

(Effects of the Invention) The electrophotographic photoreceptor of the present invention maintains the characteristics of a photoreceptor made of amorphous silicon, such as high mechanical strength, high durability, high heat resistance, and high photosensitivity, and furthermore, It has a high charge retention ability without being affected by the external environment or the number of times it is used, and can provide images of excellent quality.

Claims (1)

[Claims] An electrophotographic photoreceptor comprising a photoconductive layer and a surface layer sequentially laminated on a conductive substrate, wherein the photoconductive layer is mainly made of amorphous silicon containing hydrogen atoms and contains no impurities. Drying of a solution comprising a p-type semiconductor containing a boron atom, and further containing at least one type of a carbon atom, a nitrogen atom, and an oxygen atom, wherein the surface layer contains at least one type of organic titanium compound. An electrophotographic photoreceptor comprising a cured product.