JPS62273546A - 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 the photoconductive layer from an i-type semiconductor composed of 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 org. zirconium compd. CONSTITUTION:The photoconductive layer composed of the amorphous silicon is coated on a conductive substrate and the surface layer is laminated on said photoconductive layer. The dried curing material of the solution contg. at least one kind of the org. zirconium compd. is used as the surface layer. The i-type semiconductor contg. the amorphous silicon as the main component, and at least one kind of atom selected from carbon atom, nitrogen tom and oxygen atom as an impurity, is used as the photoconductive layer. The photoconductive layer contg. the amorphous silicon as the main component is formed on the substrate by using one kind of a silicon hydride gas such as SiH4 etc., or its mixture as a starting material by a method of glow- discharging method. 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 electrostatic charge holding power of the titled body is obtd. without being affected 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 basic structure of the photosensitive layer used in this electrophotographic method is that the photosensitive layer is laminated on a conductive substrate. Conventionally, the materials constituting photoreceptors have been non-R photosensitive materials such as selenium or selenium alloys, cadmium sulfide, and zinc oxide, or materials such as polyvinylcarbazole, trinitrofluorenone, bisazo pigments, phthalonanine, pyrazoline, and hydrazone. Organic 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, 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 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 for Solving the Problem) As a result of extensive research, the present inventor coated a photoconductive layer made of amorphous silicon on a conductive substrate, and further laminated a surface layer thereon. At the same time, as the surface layer, an organic zirconium compound is added. 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 C.

As the photoconductive layer, an l-type semiconductor mainly composed of amorphous silicon and containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms as impurities is used.

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. The surface layer is made of a type 1 semiconductor containing at least one of carbon atoms, nitrogen atoms, and oxygen atoms as impurities, and the surface layer contains at least 1+ organic zirconium compound! Provided is an electrophotographic photoreceptor comprising a dried and cured product of a solution containing Li.

Although various organic zirconium compounds can be used to form the surface layer of the electrophotographic photoreceptor of the present invention, particularly preferred are zirconium complexes and zirconium alkoxides. Preferred examples of zirconium complexes include zirconium acetoacetonate,
Zirconium tetrakis acetylacetonate, zirconium tetrakis acetylacetonate, zirconium trifluoroacetylacetonate, zirconium trifluoroacetylacetonate, zirconium tetrakis ethyl acetoacetate, zirconium butoxy tris ethyl acetoacetate, zirconium dibutoxy bis ethyl acetoacetate, These are acetylacetone zirconium complexes, such as zirconium tributoxyl ethylacetoacetate, bisacetylacetonate bisethylacetoacetate zirconium, monoacetylacetonate trisethylacetoacetate zirconium, and bisacetylacetonate bisethylacetoacetate zirconium. In addition, zirconium complexes such as zirconium tetrakisethyl lactate and zirconium dibutoxybisethyl lactate can also be used. Preferred examples of zirconium alkoxide include zirconium tetramethoxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, zirconium-n-butoxide, zirconium isobutoxide,
etc.

In order to obtain the electrophotographic photoreceptor of the present invention, a solution of one or more of the above organic zirconium compounds dissolved in a suitable solvent is coated. Further, at this time, a solution obtained by mixing these organic zirconium compounds with an organic silicon compound may be used. As this organosilicon compound, a compound generally called a silane coupling agent is suitable, such as vinyl) IJ chlorane,
Vinyltriethoxysilane, vinyltris(β-methyneethoxy)silane, r-glycidoxypropyltrimethoxysilane, r-methacryloxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-βaminoethyl)T-
Aminopropylmethyldimethoxysilane, T-chloropropyltrimethoxysilane, T-mercaptopropyltrimethoxysilane, T-aminopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxylane, trimethylmonomethoxysilane, diphenyldimethoxysilane, diphenyljetoxysilane Examples include toxysilane, monophenyltrimethoxysilane, and the like. 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, followed by 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 SiH S1□
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 H6, Si*Ha, 5i4H1°, or a mixture thereof as a raw material. Among them,
Plasma CV D (Chemical Vapor D
Shira (SI84) by eposition method
The method of decomposing gas etc. by glow discharge (glow discharge method) is
This 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 l-type semiconductor mainly composed of amorphous silicon containing hydrogen atoms and containing at least 11 types of impurities among carbon atoms, nitrogen atoms, and oxygen atoms. A photoconductive layer of the present invention that does not contain impurities for controlling the conductivity type and has a slight n-type tendency is also a photoconductive layer of the present invention, but it can be made into a complete l-type semiconductor by adding a small amount of boron atoms. Can be done.

This boron atom addition is usually performed using diborane (B2H6
) gas is used as a raw material, and by adding about 10 to 1100 pp, a perfect type 1 semiconductor amorphous silicon can be obtained.

It is also possible to add elements such as germanium (C, e) 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 AC discharge, the frequency is usually 0.1 to 30 MHz, and the vacuum during discharge. The degree is 0.1 to 5 Torr, the substrate heating temperature is 100 to
The temperature is 400°C. 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 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.

(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, the substrate temperature was maintained at a predetermined temperature of 250°C, and 100% silane (Si) was placed in the reaction chamber.
H4) gas per minute 120CC1 hydrogen dilution lOOpp
m diborane (B2H6) gas at 20 cc/min, 100% ethylene (C2H,) gas at 12 cc/min, and 100% hydrogen (N2) gas at 33 cc/min, and the inside of the reaction tank was maintained at 0.5 Torr. After maintaining the internal pressure at , 13.57 MHz alternating frequency power was applied to generate glow discharge, and the output of the high frequency power source was maintained at 85 W. In this way, a film with a thickness of 25 μm was placed on a cylindrical Aβ substrate.
A photoreceptor having a photoconductive layer made of an l-type semiconductor mainly composed of amorphous silicon and containing boron and carbon atoms as impurities was obtained. When the photoreceptor thus obtained was placed in a copying machine and the image quality was evaluated using a positive corona discharge method, an image density that was acceptable for practical use was initially obtained; however,
As the copying operation was repeated, the 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 1; Zirconium acetylacetone was deposited on a photoreceptor having a photoconductive layer made of an l-type semiconductor mainly composed of amorphous silicon and containing boron and carbon as impurities, which was prepared by the same method and under the same conditions as Comparative Example 1. A solution consisting of 1 part by weight, 50 parts by weight of methyl alcohol, and 20 parts by weight of n-butyl alcohol was applied by dip coating, and dried and cured in an oven at 200°C for 1 hour to obtain a photoreceptor having a surface layer of 0.2 μm thickness. 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 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, 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. 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. 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 AA 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 dilution: 10 Qppm diborane (B2H6) gas was introduced at a rate of 20 CC1 per minute, 100% nitrogen (N2) gas was introduced at a rate of 35 cc/min, and 100% hydrogen (N2) gas was introduced at a rate of 15 cc/min. 0.5 Torr
After maintaining the internal pressure of 13.06 M) (z), a glow discharge was generated by applying high frequency power, and the output of the high frequency power source was maintained at 85 W. In this way, the cylindrical A
42 substrate with a thickness of 25 μm, consisting mainly of amorphous silicon and containing boron atoms and nitrogen atoms as impurities.
A photoreceptor with a photoconductive layer made of a type semiconductor was put into a copying machine and the image quality was evaluated using a positive corona charging method. Although an image density with no blemish was obtained, as copying operations were repeated, the image density gradually decreased.Furthermore, when this photoreceptor was evaluated for image quality in an environment of 30°C and 85% RH, it was found that the image density was lower than that at the initial stage. flow was observed.

Example 2: On a photoreceptor having a photoconductive layer made of an l-type semiconductor mainly composed of amorphous silicon and containing boron and nitrogen, which was prepared by the same method and under the same conditions as Comparative Example 2, zirconium tetrabutoxide 1 A solution consisting of 100 parts by weight of ethyl alcohol was applied by dip coating, 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 0.2 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°C.
Image quality was evaluated under an environment of 85% 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 3: A β substrate was installed in a cylindrical shape at a predetermined position in a reaction chamber of a coupled plasma CVD apparatus, the substrate temperature was maintained at a predetermined temperature of 250°C, and 100% silane (S) was placed in the reaction chamber.
IH4) 120cc of gas per minute, ICLOp with hydrogen dilution
pm Diborane (B2H6) gas at 20 cc/min and 100% oxygen (02) gas at 10 cc/min, and 1
After introducing 00% hydrogen (H2) gas at a rate of 99 cc per minute and maintaining the internal pressure in the reaction tank at 0.5 Torr, 13.5
Alternating frequency power of 6 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 l-type semiconductor mainly composed of amorphous silicon and containing boron and oxygen atoms as impurities on a cylindrical AI substrate. Insert the photoreceptor that has been processed in this way into the copying machine,
When the image quality was evaluated using a positive corona charging method, an image density with no practical problems was obtained at the initial stage, but as copying operations were repeated, the image density gradually decreased. Also,
When this photoreceptor was evaluated for image quality under an environment of 30° C. and 85% R), image flow was observed from the initial stage.

Example 3: A material mainly composed of amorphous silicon and containing boron and oxygen as impurities was prepared by the same method and under the same conditions as Comparative Example 3.
1 part by weight of zirconium tetrabutoxide, 1 part by weight of methyltrimethoxysilane, 100 parts by weight of ethyl alcohol,
A solution consisting of 100 parts by weight of inpropyl alcohol was applied by dip coating, dried and cured in an oven at 200°C for 1 hour, and 0.1
A photoreceptor having a surface layer of μ thickness is called f4. 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.
The image quality was evaluated in an environment of , 85% R1, and the image showed high resolution with no noticeable flow. At the same time, the copying test conducted with the negative corona charging method was as good as with the positive charging method. gave good results.

(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 that is not affected by the external environment or the number of times of use, and can provide images of excellent quality.

Claims (2)

[Claims] (1) 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, and contains carbon atoms as impurities. , an i-type semiconductor containing at least one of nitrogen atoms and oxygen atoms, and the surface layer contains at least one organic zirconium compound.
1. A photoreceptor for electrophotography, characterized in that it is made of a dried and cured product of a solution containing various types of photoreceptors. (2) The electrophotographic photoreceptor according to claim (1), wherein the organic zirconium compound is a zirconium complex or a zirconium alkoxide.