JPS62273563A - 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 semiconductor comprising an amorphous silicon contg. hydrogen atom as a main component, 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 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. titanium compd. is used as the surface layer. The p-type semiconductor contg. the amorphous silicon as the main component, and boron atom as an impurity is used as the photoconductive layer. The further preferable org. titanium compd. is a titanium complex and titanium alkoxide. The org. titanium compd. is preferably exemplified 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 a firefly layer. 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 (SiH4) gas using a glow discharge decomposition method or the like.
Hydrogen atoms are incorporated into the amorphous silicon film 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, when an amorphous silicon photoreceptor is charged, imagewise exposed to form an electrostatic latent image, and then developed, the surface charge on the photoreceptor is not irradiated with light until the imagewise exposure step or the development step. Even the charge on the parts that are not affected is attenuated, 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.

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 snow surrounding 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 mainly composed of amorphous silicon and 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. Provided is an electrophotographic photoreceptor comprising a p-type semiconductor containing boron atoms as an impurity, the surface layer comprising a dried and cured product of a solution containing at least one organic titanium compound.

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:
Diisopropoquine titanium bis(acetylacetonate)
, polytitanium acetylacetonate, bis(acetylacetonate) titanium oxide, titanium tetramethoxide, titanium tetraethoxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetrabutoxide, titanium tetraisobutokind, etc. can be mentioned.

In order to obtain the electrophotographic photoreceptor of the present invention, a solution of 11 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. As the second organosilicon compound, compounds generally called silane coupling agents are suitable, such as vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, T-glycidoxypropyltrisilane, etc. Methoxysilane, γ
-methacryloxypropyltrimethoxysilane, N-
β (aminoethyl) T-aminopropyltrimethoxysilane, N-β (aminoethyl) T-aminopropylmethyldimethoxysilane, γ-talolopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
T-aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmonomethoxysilane, diphenyldimethoxysilane,
Examples include 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 is processed by coating by spray coating, dip coating, knife coating, roll coating, or the like, followed by drying and curing. The drying and curing temperature can be set at any temperature between 100 and 400°C. 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 SiH, 5I
Using one type of hydrogen silicon gas such as 2H6, S+J= , 51481°, or a mixture thereof as a raw material, 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. Among them, Bladder 7 CV D (Chemical Vapor
Silane (5iH4
) 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 (B2) 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 semiconductor mainly composed of amorphous silicon containing hydrogen atoms. It can be a complete 1-type or n-type semiconductor. For this addition of boron atoms, diborane (B2H8) gas is usually used as a raw material, and 0.01~
n-type semiconductor by adding about l atomic %, 10
By adding about -3 to 10-2 atomic percent, amorphous silicon, which is a complete l-type semiconductor, can be obtained. For the 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 phosphorus atoms in an amount of 10-6 to 10-1 atomic percent. Although the photoconductive layer of the present invention does not contain impurities for controlling the conductivity type, it is well known that when it does not contain boron atoms, amorphous silicon is n-type with a slight tendency to be n-type. It is being

Furthermore, halogen atoms or the like may be contained in the photosensitive layer for the purpose of increasing the dark resistance, photosensitivity, or chargeability (charging potential per unit thickness) of the photosensitive layer.

Furthermore, 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.

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 Q, l ~ 5 Torr, substrate heating temperature is 101
The temperature is 13-400°C. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon is 1 to 100 μm, particularly 10 to 100 μm.
The thickness is preferably 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 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.
H,) gas per minute with loOppm of hydrogen dilution of 120c3
20cc of diborane (BJg) gas per minute, then 100cc of diborane (BJg) gas per minute.
% hydrogen (H2) gas was introduced at a rate of 9 (Lee) per minute, and the internal pressure inside the reaction tank was maintained at 0.5 Torr.
．． A high frequency power source of 57M) Iz was turned on 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 25 μm thick photoconductive layer made of a type 1 semiconductor mainly composed of amorphous silicon and containing boron atoms as impurities on a cylindrical flexible 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, 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.

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

Example 1: On a photoreceptor having a photoconductive layer made of a type 1 semiconductor mainly composed of amorphous silicon and containing boron as an impurity, which was prepared by the same method and under the same conditions as Comparative Example 1, diisopropoxychipone was applied. 1 part by weight of acetylacenate),
A solution consisting of 20 parts by weight of n-butyl alcohol was applied and dried and cured in an oven at 200°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 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℃, 8
Image quality was evaluated under an environment of 5% RH, but no image flow was observed, indicating high resolution. 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 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 (SiH) was placed in the reaction chamber.
,) 120 cc/min of gas, 500 ppm of hydrogen dilution
Diborane (82H6) gas at 20cc/min, and 1
After flowing 00% hydrogen (H2) gas at a rate of 80 cc per minute and maintaining the internal pressure in the reaction tank at 0.5 Torr,
A high frequency power source of 13.56 MHz was turned on 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 boron atoms as impurities on a cylindrical quasi-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, 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. Furthermore, when we evaluated the image quality of this photoreceptor under an environment of 30°C and 85% RH, we found that
Image flow was observed from the beginning.

Example 2: Tetraethyl orthotitanate 1 was deposited on a photoreceptor having a photoconductive layer made of a p-type semiconductor mainly composed of amorphous silicon and containing boron as an impurity, which was produced by the same method and under the same conditions as Comparative Example 2. Parts by weight, isopropyl alcohol 3
A solution consisting of 0 parts by weight was applied and dried and cured in an oven at 200° C. for 1 hour to obtain a photoreceptor having a surface layer with a thickness of 0.3 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 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℃, 8
Image quality was evaluated under an environment of 5% RH, but no image flow was observed, indicating high resolution.

Comparative Example 3: A cylindrical quasi-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 (5IH) was placed in the reaction chamber.
4) 120cc of gas per minute, 300ppm of hydrogen dilution
Phosphine (PH3) gas 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 to maintain the internal pressure in the reaction tank at Q, 5 Torr, then a 13.56 MHz high frequency power source was applied. The output of the high frequency power source was maintained at 85W by turning on the battery to generate a glow discharge. In this way, a thickness of 25 μm was placed on a cylindrical substrate.
A photoreceptor having a photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus 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 negative corona charging method, the image density was found to be 100%, which was acceptable for practical use at the initial stage, but as copying operations were repeated, Image density gradually decreased. Further, when the image quality of this photoreceptor was evaluated in an environment of 30° C. and 85% RH, image flow was observed from the initial stage.

Example 3: Tetrabutyl orthotitanate was deposited on a photoreceptor having a photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing boron as an impurity, which was produced by the same method and under the same conditions as Comparative Example 3. 1 part by weight, 1 part T-acrylogine propyltrimethoxysilane 18'B, 1 part methyl alcohol
A solution consisting of 0 parts by weight and 20 parts by weight of isopropyl alcohol was applied and dried and cured in an oven at 200°C for 1 hour.
．． A photoreceptor having a surface layer with a thickness of 3 μm was obtained. 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 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. This photoreceptor was heated at 30℃, 8
Image quality was evaluated under an environment of 5% RH, but no image flow was observed, indicating high resolution.

(Effects of the Invention) The electrophotographic photoreceptor of the present invention maintains the excellent properties 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)

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