JPS62273555A - 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. aluminium 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. aluminium compd. is used as the surface layer. The n-type semiconductor comprising the amorphous silicon as the main component and the phosphorous atom as the impurity is used as the photoconductive layer. The further preferable org. aluminium compd. is an aluminium complex and an aluminium alkoxide. The org. aluminium compd. is exemplified by further preferably aluminium trisacetyl 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 Industrial Application Field The present invention relates to an electrophotographic photoreceptor, particularly 1. an electrophotographic photoreceptor using amorphous silicon for photosensitivity; related.

In the conventional electrophotographic method, an electrostatic latent image is formed by charging a photoreceptor and exposing the image to light, and after developing this latent image with a developer, the toner image is transferred to a transfer paper and fixed to form a copy. It is known as a method of obtaining The basic structure of the photoreceptor used in this electrophotographic method is that a photosensitive layer is 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 high photosensitivity (
It also has excellent 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,
Next, during development, the surface charge on the photoreceptor decreases until the exposure step (or even the charge on the part that has not been exposed to light) until the development step, and the charge potential required for development decreases. is not obtained. 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 outer hole 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 dry cured product of a solution containing at least one type of organoaluminum 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. Drying of a solution consisting of an n-type semiconductor containing phosphorus atoms as impurities, further containing at least one type of carbon S atoms, oxygen atoms, or nitrogen atoms, and the surface layer containing at least one type of organoaluminum compound. There is provided an electrophotographic photoreceptor characterized by being made of a cured product.

Although various organic aluminum compounds can be used to form the surface layer of the electrophotographic photoreceptor of the present invention, aluminum complexes and aluminum alkoxides are particularly preferred. Preferred examples of these include aluminum trisacetylacetonate, aluminum methoxide, aluminum ethoxide, aluminum isobropoquine, aluminum-n-
propoxide, aluminum-Sec-butoxide,
Examples include aluminum-n-butoxide.

In preparing the electrophotographic photoreceptor of the present invention, a solution containing one or more of the above organoaluminum compounds dissolved in a suitable solvent is applied. Also, at this time,
A solution obtained by mixing these finite aluminum compounds with an organosilicon compound may also be used. Compounds generally called silane coupling agents are suitable as the organosilicon compound, such as vinyl) IJ dichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, and T-glycidquinpropyltrimethoxy. Silane, r-methacryloxypropyltrimethoxysilane, N-β(aminoethyl)T-aminepropyltrimethoxysilane, N-β(aminoethyl)r-
Aminopropylmethyldimethoxysilane, r-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, T-aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmonomethoxysilane, diphenyldimethoxysilane, Examples include diphenylshedoxinlan, monophenyltrimethoxysilane, and the like. When such a silane coupling agent is mixed and used, the silane coupling agent accounts for 5 to 50% of the total solid weight.
It is better to make it so that

Thus, a solution containing an organoaluminum 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. Although the thickness of the final surface layer can be set arbitrarily, it is preferably 0.1 to 10 μm.

The photoconductive layer mainly composed of amorphous silicon is SiH S+2
Using one type of hydrogen silicon gas such as Hs, 5IJs% 514H+O, 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 by a method such as a vacuum evaporation method. Among them, Bladder 7 CV D (Chemical Vapo
Silane (S+
H< ) A method of decomposing gas or 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.

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 phosphorus atoms in an amount of 0.01 to 11,000 pp.

Further, the electrophotographic photoreceptor according to the present invention further contains at least one type of carbon atom, nitrogen atom, or oxygen atom. The content of such atoms is
In particular, an increase in the dark resistance of the photosensitive layer film, an increase in photosensitivity, and furthermore,
This is preferable from the viewpoint of increasing charging ability (charging potential per unit film thickness).

Furthermore, it is also possible to add elements 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, in a plasma CVD apparatus, silicon hydride gas, which is the main raw material, and hydrogen gas, if desired, are added together with these gases. Glow discharge decomposition may be performed by introducing a gaseous compound containing the necessary elements. As mentioned above, plasma CVD? , 4, effective discharge conditions for forming a photoconductive layer made of amorphous silicon include, for example, in the case of alternating current discharge, the frequency is usually 0.1 to 30! , IHz, vacuum degree during discharge is 0, 1 to 5 Torr, substrate heating temperature is 1
00-400°C. Therefore, the film thickness of the photoconductive layer mainly composed of amorphous silicon: well, 1 to 100 μm, especially 10 μm.
It is suitable that the thickness is 50 μm.

As the conductive substrate, metals such as aluminum, nickel, chromium, stainless steel, or brass, plastic 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 arbitrary shape, such as a cylinder, a flat plate, or an endless belt.

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 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.
84) 129cc of gas per minute, 300% of hydrogen dilution
ppm phosphine (PH,) gas at 30cc per minute
, and 100% ethylene (C2H4) gas at 15 cc/min, and 100% hydrogen (N2) gas at 7 cc/min.
After inflowing at 5 cc and maintaining the reactor at an internal pressure of 0.5 Torr, 13.56! , 1Hz high-frequency power is applied to generate a glow discharge, and the output of the high-frequency power supply is increased to 8.
It was maintained at 5W. In this way, a photoreceptor was obtained having a 25 μm thick photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus and carbon as impurities on a cylindrical AI2 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 sufficient for practical use was not obtained. In addition, this photoreceptor was
When image quality was evaluated under an environment of 85% RH and 85% RH, image flow was observed.

Example 1゜ Aluminum trisacetylacetate was deposited 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 prepared by the same method and under the same conditions as Comparative Example 1. A solution consisting of 1 part by weight of f-81 and 30 parts by weight of isopropyl alcohol was applied by dip coating, and the mixture was heated at 250°C for 2 hours.
After drying and curing for a period of time, a photoreceptor having a surface layer with a thickness of 0.1 μm 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, the image density was increased by 1 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. 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 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.
)I4) 12 Qcc of gas per minute, 300p of hydrogen dilution
pm Bosphin (PH3) gas was introduced at 3 Qcc per minute, 100% nitrogen (N2) gas was introduced at 9 Qcc per minute, and 100% hydrogen (N2) gas was introduced at IQcc per minute.
After maintaining the internal pressure in the reaction tank at Q, 5 Torr, 13.
High frequency power of 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 having a 25 μm thick photoconductive layer made of an n-type semiconductor mainly composed of amorphous silicon and containing phosphorus and nitrogen as impurities was obtained, which was formed on a cylindrical Al 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 flow was observed from the initial stage.

Example 2: On a photoreceptor having a photoconductor 1 made of an n-type semiconductor mainly made of amorphous silicon and containing phosphorus and nitrogen, which was produced by the same method and under the same conditions as Comparative Example 2, an aluminum-S
A solution consisting of 1 part by weight of ea-butoxide and 40 parts by weight of ethyl alcohol was applied by dip coating and dried and cured at 200 DEG C. for 1 hour to form a photoreceptor having a 0.2 .mu.m thick surface layer. The smooth surface layer has properties similar to ceramics,
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 positive corona charging method, an image density that was acceptable for practical use was obtained at the initial stage. In addition, the image quality of this photoreceptor, which had been copied 50,000 times without any decrease in image density, was evaluated in an environment of 30°C and 85% R11, but no image bleeding was observed. showed the 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% furan (Sl) was placed in the reaction chamber.
) + 4 > 120cc of gas per minute, 30 Q of hydrogen dilution
ppm phosphine (PH3) gas 33cc per minute
, and 100% oxygen (02) gas per minute. Qc
c. Furthermore, 100% hydrogen (H2) gas was introduced at a rate of 39 cc per minute to maintain the internal pressure in the reaction tank at 0.5 Torr, and then 13.56 MHz high frequency power was applied to generate a glow discharge and high frequency Power supply output was maintained at 35 W. In this way, a 25 μm thick amorphous silicon was deposited on a cylindrical Af substrate, with phosphorus as an impurity and
Furthermore, a photoreceptor having a photoconductive layer made of an n-type semiconductor containing oxygen was obtained.

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: Zirconium tetrabutoxide was deposited 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 produced by the same method and under the same conditions as Comparative Example 3. On top, aluminum-Sec
- Dip-coating a solution consisting of 1 part by weight of butoxide, 1 part by weight of methyltrimethoxysilane, 30 parts by weight of isopropyl alcohol, and 30 parts by weight of ethyl alcohol,
The photoreceptor was dried and cured at ℃ for 1 hour to obtain a photoreceptor having a surface layer of 0.2 μm thick. 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 in an environment of 30° C. and 85% RHO, 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 that is not affected by the number of times it is used 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 mainly composed of amorphous silicon containing hydrogen atoms and contains impurities. Drying and curing of a solution consisting of an n-type semiconductor containing phosphorus atoms and further containing at least one type of carbon atom, nitrogen atom, or oxygen atom, wherein the surface layer contains at least one type of organoaluminum compound. An electrophotographic photoreceptor characterized by being made of a material.