JP2008076520A - Electrophotographic photoreceptor, and process cartridge and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor excellent in mechanical durability, sensitivity and oxidation resistance of the surface, suppressing an image defect caused by deposition of a discharge product, and maintaining the characteristics at a high level with time, and to provide a process cartridge and an image forming apparatus using the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor comprises a photosensitive layer, an intermediate layer and a surface layer stacked in this order on a conductive substrate, wherein both of the intermediate layer and the surface layer contain a group 13 element and at least one of oxygen and nitrogen, and at least one of the kind and the composition ratio of the included element differs between the intermediate layer and the surface layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member used in a copying machine or the like for forming an image by an electrophotographic method, and a process cartridge and an image forming apparatus using the same.

  In recent years, electrophotographic methods have been widely used for copying machines, printers, and the like. An electrophotographic photosensitive member (hereinafter sometimes referred to as a “photosensitive member”) used in an image forming apparatus using such an electrophotographic method is exposed to various contacts and stress in the apparatus. Although this causes degradation, on the other hand, high reliability is required as the image forming apparatus is digitized and colorized.

  For example, when paying attention to the charging process of the photoreceptor, there are the following problems. First, in the non-contact charging method, the discharge product adheres to the photoconductor, causing image blur and the like. Therefore, in order to remove the discharge products adhering to the photosensitive member, for example, a system in which particles having an abrasive function are mixed in the developer and scraped off by the cleaning unit may be employed. In this case, the surface of the photoreceptor is deteriorated due to wear. On the other hand, in recent years, the contact charging method has been widely used. Even in this method, the wear of the photosensitive member may be accelerated.

From such a background, the electrophotographic photoreceptor is required to have a longer life. In order to extend the life of the electrophotographic photoreceptor, it is necessary to improve the wear resistance, and therefore it is required to increase the hardness of the photoreceptor surface.
However, in a photoconductor whose surface is made of amorphous silicon having a high hardness, adhesion of discharge products and the like are liable to occur, and image blurring and image blurring are likely to occur, and this phenomenon is particularly remarkable at high humidity. The same applies to the surface layer of the organic photoreceptor having the organic photosensitive layer.

In order to suppress the occurrence of such a problem, a carbon-based material is often used as the surface layer of the photoreceptor.
For example, a method of forming an amorphous silicon carbide surface protective layer on a photosensitive organic layer using a catalytic CVD method (see, for example, Patent Document 1), in amorphous carbon for the purpose of improving moisture resistance and printing durability. (See, for example, Patent Document 2), a technique using diamond-bonded amorphous carbon nitride (see, for example, Patent Document 3), and a technique using a non-single-crystal hydrogenated nitride semiconductor (see, for example, Patent Document 2). For example, see Patent Document 4).

  However, in the case of a carbon-based film, for example, a hydrogenated amorphous carbon film (aC: H) or a film (aC: H, F) obtained by fluorinating the film, if the hardness of the film is improved, the film Tends to be colored. Therefore, when a surface layer made of a carbon-based film is worn by use, the light transmission amount of the surface layer increases with time, and the sensitivity of the photosensitive layer provided inside the surface layer increases. There was a problem. In addition, if the surface layer wear in the surface direction is uneven, the sensitivity of the photosensitive layer also becomes non-uniform, so that there is a problem that image unevenness is likely to occur particularly when a halftone image is formed. .

  On the other hand, as a general characteristic of carbon-based thin film materials, it is known that there is a trade-off relationship between improvement in hardness and improvement in transparency. When focusing on the carbon bonds in the film, it is necessary to increase the diamond-type sp3 bonding property in order to increase the hardness. However, in these films, there is a graphite-type sp2 that absorbs light. In addition to unavoidable bonding, it is possible to suppress the presence of graphite-type sp2 bonds by adding hydrogen to the film, etc., but the transparency improves but the film quality becomes an organic film and the hardness decreases. Because it will do.

  In recent years, research and development of carbon nitride films have also been carried out, but they have not reached the hardness and characteristics higher than those of conventionally known carbon-based thin films such as diamond films and diamond-like carbon films. In order to obtain a harder and denser film, heating at about 1000 ° C. is required at the time of film formation, and the discharge power must be increased. However, film formation methods based on such high temperature and high energy discharge conditions are difficult to apply to organic photoreceptors that are easily damaged by heat and discharge, such as organic photoreceptors, and are not practical. .

Thus, the conventional carbon-based thin film is insufficient as a surface layer of a photoreceptor in terms of both hardness and transparency. On the other hand, the hydrogenated amorphous silicon carbide film (a-SiC: H) is excellent in this respect. However, image blur and image drift are likely to occur due to adhesion of discharge products, etc., and it is necessary to use a drum heater to suppress these occurrences.
Furthermore, although the hydrogenated nitride semiconductor is excellent in hardness and transparency, it lacks water resistance in a high humidity environment and is inferior in practicality.

For these problems, for example, it has been proposed to use magnesium fluoride for the surface layer (see, for example, Patent Document 5). However, since magnesium fluoride dissolves in water and acid, the moisture resistance in a high humidity atmosphere is insufficient.
Further, in Patent Document 4, a surface layer of an electrophotographic photoreceptor using a non-single crystal group III nitride compound semiconductor using remote plasma is proposed. However, when a non-single crystal group III nitride compound semiconductor is used as the surface layer of the organic photoreceptor, there is a problem that the surface of the organic polymer is damaged by heat because the substrate temperature and the surface temperature at which the semiconductor grows are different. However, it was impossible to make use of the transparent and smooth characteristics of the original organic polymer film. Even if the electrical characteristics are good, in the case of an electrophotographic photoreceptor, the surface is exposed to contact by corona discharge, development with toner, cleaning, etc., so that the printing durability is insufficient.

On the other hand, a method of forming a surface layer by a coating method has been proposed in contrast to the method of forming a surface layer using film formation in the gas phase as described above. Among these, in order to improve the wear resistance, it is known to use a surface layer using a polymer compound having a siloxane bond. However, a surface layer made of such a material has a lower hardness than a surface layer formed using vapor phase film formation. For this reason, when the surface of the photoconductor is scratched or worn out over time, the adhesion of the surface is increased, and the lifetime of the photoconductor is reduced by the toner adhering to the surface of the photoconductor. There's a problem.
JP 2003-316053 A JP-A-2-110470 JP 2003-27238 A Japanese Patent Laid-Open No. 11-186571 JP 2003-29437 A

  As described above, as the surface layer of the photoreceptor, both high hardness and excellent transparency can be achieved, and image defects due to adhesion of discharge products can be suppressed. Furthermore, these characteristics are improved over time. Although it is required to be maintained at a level, it has been difficult to achieve all these characteristics at a high level with conventionally known materials.

An object of the present invention is to solve the above problems.
That is, the present invention is excellent in mechanical durability and oxidation resistance of the surface, can suppress image defects due to adhesion of discharge products, is excellent in sensitivity, and further, these characteristics at a high level with time. It is an object of the present invention to provide an electrophotographic photosensitive member that can be easily maintained, and a process cartridge and an image forming apparatus using the same.

The above object is achieved by the present invention described below. That is, the present invention
<1> A photosensitive layer, an intermediate layer, and a surface layer are laminated in this order on a conductive substrate,
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the types and composition ratios of the contained elements in the intermediate layer and the surface layer is different. An electrophotographic photoreceptor.

<2> The layer thickness including the surface layer and the intermediate layer is 0.1 μm or more and less than 5 μm, and is in the range of 0.5 to 10% with respect to the layer thickness of the photosensitive layer. This is an electrophotographic photoreceptor.

<3> The electrophotographic photosensitive member according to <1>, wherein the surface layer contains hydrogen.

<4> The electrophotographic photosensitive member according to <1>, wherein the photosensitive layer includes an organic material.

<5> An electrophotographic photosensitive member formed by laminating a photosensitive layer, an intermediate layer, and a surface layer in this order on a conductive substrate, and at least one selected from a charging unit, a developing unit, and a cleaning unit. As one,
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the types and composition ratios of the contained elements in the intermediate layer and the surface layer is different. Process cartridge.

<6> An electrophotographic photosensitive member constituted by laminating a photosensitive layer, an intermediate layer, and a surface layer in this order on a conductive substrate, charging means for charging the surface of the electrophotographic photosensitive member, and the charged An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, a developing means for developing the electrostatic latent image as a toner image with a developer containing toner, and the toner image on a recording medium. And at least a transfer means for transferring,
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the types and composition ratios of the contained elements in the intermediate layer and the surface layer is different. An image forming apparatus.

  As described above, according to the present invention, the surface has excellent mechanical durability and oxidation resistance, can suppress image defects due to adhesion of discharge products, and has excellent sensitivity. Can be easily maintained at a high level over time, and a process cartridge and an image forming apparatus using the same can be provided.

Hereinafter, the present invention will be described in detail.
<Electrophotographic photoreceptor>
The electrophotographic photoreceptor of the present invention is constituted by laminating a photosensitive layer, an intermediate layer, and a surface layer in this order on a conductive substrate, and each of the intermediate layer and the surface layer includes a group 13 element, oxygen, and It contains at least one of nitrogen, and the composition ratio of the contained elements in the intermediate layer and the surface layer is different.

  Since the surface layer in the photoconductor of the present invention contains an oxide or nitride of a group 13 element, the surface of the photoconductor is protected against an oxidizing atmosphere generated by a charger or ozone or nitrogen oxide in the image forming apparatus. It is difficult to oxidize itself, and the deterioration of the photoreceptor due to oxidation can be prevented. Moreover, since it is excellent in mechanical durability and oxidation resistance as mentioned above, it is easy to maintain these characteristics at a high level over a long period of time. In addition, the surface of the photoreceptor exposed to rubbing by a cleaning blade is excellent in abrasion resistance, and the occurrence of scratches on the surface of the photoreceptor can be suppressed, and good sensitivity can be easily obtained.

However, since the surface layer is a hard inorganic thin film, especially when the photosensitive layer is made of an organic material, the thermal expansion coefficient of the photosensitive layer and the surface layer are different, and the strain characteristics with respect to stress are greatly different. In some cases, mechanical stress may occur between the two layers. Further, when the film thickness is increased in order to improve the mechanical characteristics, there is an increase in the residual potential and the like, and the electrical characteristics deteriorate and there is a problem in image density and uniformity.
The inventors of the present invention have intensively studied the above problem and solved the above problem by providing an intermediate layer containing elements of the same type as the surface layer in different types and composition ratios between the surface layer and the photosensitive layer. I found out that

  Specifically, since the intermediate layer in the present invention similarly contains at least one of group 13 elements and oxygen and nitrogen contained in the surface layer described later, the adhesion with the surface layer is good, and In addition, the thermal expansion coefficient and elastic modulus of the intermediate layer can also be made closer to the photosensitive layer than the surface layer by changing the composition of the contained elements, and also serves as a buffer between the intermediate layer and the photosensitive layer. . Note that the intermediate layer may contain only a group 13 element and nitrogen, or may contain oxygen. Moreover, it is preferable that oxygen is less than the amount of oxygen contained in the surface layer. Further, it may be composed of a group 13 element and oxygen, and is particularly preferable because the residual potential can be controlled by reducing the electric resistance by making the amount of oxygen smaller than that of the surface layer.

Hereinafter, the structure of the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the photoreceptor of the present invention. In FIG. 1, 1 is a conductive substrate, 2 is a photosensitive layer, 2A is a charge generation layer, 2B is a charge transport layer, 3 Represents a surface layer and 5 represents an intermediate layer. 4 is an undercoat layer. 1 has a layer structure in which a charge generation layer 2A, a charge transport layer 2B, an intermediate layer 5, and a surface layer 3 are laminated in this order on a conductive substrate 1, and the photosensitive layer 2 has a charge generation. It is composed of two layers, a layer 2A and a charge transport layer 2B.

FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor of the present invention. In FIG. 2, 6 represents a photosensitive layer, and the other parts are the same as those shown in FIG.
The photoreceptor shown in FIG. 2 has a layer structure in which a photosensitive layer 6, an intermediate layer 5, and a surface layer 3 are laminated in this order on a conductive substrate 1, and the photosensitive layer 6 is shown in FIG. 1 and FIG. This is a layer in which the functions of the charge generation layer 2A and the charge transport layer 2B are integrated.
The photosensitive layers 2 and 6 may be formed from an organic polymer, may be formed from an inorganic material, or may be a combination thereof.

(Middle layer)
The intermediate layer 5 in the present invention is disposed between the photosensitive layer 2 and the surface layer 3. In particular, an electrophotographic photosensitive member having a surface layer of an inorganic thin film containing a group 13 element and at least one of nitrogen and oxygen, which will be described later, includes the group 13 element and at least one of nitrogen and oxygen in the present invention. By providing the intermediate layer, the mechanical stress due to the difference in hardness and expansion coefficient between the surface layer 3 and the photosensitive layer 2 can be reduced, and the charge transport layer is formed by irradiation with plasma electrons or ion UV during film formation. Fatigue such as (CTL) can be prevented. In addition, the electrical characteristics and mechanical and chemical stability can be separated from each other, the residual potential can be lowered, and cycle characteristics and environmental fluctuations can be improved.

Further, it is possible to prevent the photosensitive layer 2 from being affected by short-wavelength light such as corona discharge and ultraviolet rays from various light sources when a photoreceptor is used in the image forming apparatus. In particular, when there is no intermediate layer in the present invention, when the surface layer 3 is made thick, the cleaner system, paper, transfer mechanism, etc., which are applied cumulatively at the time of print output due to the stress inherent in the CTL immediately after film formation Due to the mechanical stimulation, micro cracks and defects are generated on the surface of the photosensitive layer, and it is possible to prevent problems such as image density unevenness caused by deterioration of charge transportability and non-uniform transport.
As a result, it has excellent mechanical durability and oxidation resistance on the surface, can suppress image defects due to adhesion of discharge products, has excellent sensitivity, and has excellent uniformity in image output characteristics over time. An electrophotographic organic photoreceptor that can be easily maintained at a high level can be provided.

The intermediate layer 5 is formed to include a group 13 element and at least one of nitrogen and oxygen, but may be a stack of a group 13 element and a nitrogen compound and a group 13 element and oxygen compound. Specifically, for example, a stacked layer of a compound of Ga and nitrogen and a compound of Al and oxygen, or a stacked layer of a compound of Ga and nitrogen and a compound of Ga and oxygen may be used. Further, a laminate of Ga and oxygen and a compound of Ga and nitrogen may be used.
In any case, it is desired that the intermediate layer 5 in the present invention has high hardness and excellent transparency, but has a thermal expansion coefficient intermediate between the surface layer 3 and the photosensitive layer 2, and the photosensitive layer. 2 and those having good adhesiveness are preferred.

Specifically, as the group 13 element contained in the intermediate layer 5, at least one element selected from B, Al, Ga, and In can be used, and two or more elements selected from these elements can be used. Combinations of elements can also be used.
In this case, the combination of the contents of these atoms in the intermediate layer is not limited, but among the above four elements, In is absorbed in the visible light region, and elements other than In are in the visible light region. Since there is no absorption, it is possible to arbitrarily adjust the sensitive wavelength range of the intermediate layer 5 with respect to light by appropriately selecting the group 13 element to be used. For example, as the constituent element of the intermediate layer 5, it is necessary to select an element so as not to absorb as much light as possible with respect to the exposure wavelength and the erase wavelength of the electrophotographic apparatus provided with this photoreceptor.

  In the present invention, both the surface layer 3 and the intermediate layer 5 contain a group 13 element and nitrogen or oxygen, but both layers differ in at least one of the type and composition ratio of the contained elements. Specifically, in order to obtain the preferable characteristics, the intermediate layer 5 is formed of a nitride when the surface layer 3 is an oxide with respect to the types of elements contained in the surface layer 3, For the nitride surface layer 3, the intermediate layer 5 is preferably a nitride having a different group 13 element. With respect to the composition ratio of the contained elements, the intermediate layer 5 is different from the oxide surface layer 3. The oxygen concentration is preferably lower than that of the surface layer 3. In this case, even when the oxygen concentration is slightly different within a few percent, it includes the case where the visible absorption spectrum and electrical conductivity are different.

More specifically, for example, when the surface layer 3 includes a compound of Ga and nitrogen, the intermediate layer 5 includes a compound of Al and nitrogen, and when the surface layer 3 includes a compound of Ga and oxygen, the intermediate layer 5 is intermediate. The layer 5 preferably contains a compound of Ga and nitrogen or a compound of Al and nitrogen (which may contain oxygen).
In addition, when the surface layer 3 contains the compound of Ga, oxygen, and nitrogen, it is preferable that the intermediate | middle layer 5 is a compound containing the same element (however, the composition ratio of both layers differs in this case).

When the intermediate layer 5 contains nitrogen, oxygen, and a group 13 element, the atomic ratio of these elements is preferably 0.5: 1 to 3: 1. If it is out of this range, there are few portions where tetrahedral bonds or three-dimensional bonds are formed, and it becomes ionic molecule-bonded, so that sufficient chemical stability and hardness cannot be obtained.
When the intermediate layer 5 contains oxygen and a group 13 element, the ratio of the number of atoms contained is preferably 0.1: 1 to 3: 1. Below 0.1, the electrical resistance is low and the latent image cannot be held. When the ratio is 3: 1 or more, defects are increased in the film, and sufficient chemical stability and hardness cannot be obtained.

  In addition, the composition of the group 13 element, nitrogen, and oxygen in the thickness direction of the intermediate layer 5 may be uniform, but the nitrogen concentration distribution increases toward the substrate in the thickness direction of the intermediate layer 5. The oxygen concentration distribution may decrease toward the substrate side, and when nitrogen and oxygen are included at the same time, the nitrogen concentration distribution decreases toward the substrate side and the oxygen concentration distribution is You may increase toward the base material side.

  The intermediate layer 5 may contain only the group 13 element and nitrogen and / or oxygen, but may contain other elements such as hydrogen as necessary, particularly hydrogen. It is preferable that In this case, hydrogen increases electrical stability, chemical stability and mechanical stability by compensating for dangling bonds and structural defects generated by the combination of Ga element, nitrogen and oxygen, and high. In addition to hardness and transparency, a high water repellency and low friction coefficient on the surface of the intermediate layer film can be obtained.

When hydrogen is contained in the intermediate layer, the hydrogen content in the intermediate layer is preferably in the range of 0.1 atomic% to 40 atomic%, and more preferably in the range of 0.5 to 30 atomic%.
When the hydrogen content is less than 0.1 atomic%, structural disturbances remain built in the film, which may cause electrical instability and insufficient mechanical characteristics. In addition, when it exceeds 40 atomic%, the probability of hydrogen bonding to two or more atoms of group 13 elements and nitrogen atoms increases, and a three-dimensional structure cannot be maintained, and hardness and chemical stability (especially water resistance) Etc. may be insufficient.

The amount of hydrogen contained in the intermediate layer 5 is 0.1 atomic% or more and 50 atomic% or less with respect to the entire two main elements (Group 13 element and oxygen or Group 13 element and nitrogen) constituting the intermediate layer 5. Is preferable, and the range of 1 atomic% to 40 atomic% is more preferable.
In the present invention, the hydrogen content in the intermediate layer means a value obtained by hydrogen forward scattering (HFS). The measurement method will be described later.

Further, the intermediate layer may contain carbon, but the content in this case is preferably 15 atomic% or less. If the carbon content exceeds 15 atomic%, carbon is present in the intermediate layer as —CH ₂ , —CH ₃ , so that the amount of hydrogen contained in the intermediate layer increases. As a result, in the atmosphere of the intermediate layer In some cases, the chemical stability or the like is insufficient.

  In the present invention, the content of group 13 elements and elements such as nitrogen, oxygen, and carbon in the intermediate layer means values obtained by Rutherford back scattering (RBS) including distribution in the film thickness direction. The measurement method will be described later.

Whether the intermediate layer 5 is crystalline / non-crystalline is not particularly limited, and may be microcrystalline, polycrystalline, or amorphous.
The intermediate layer 5 may be amorphous containing microcrystals or microcrystalline / polycrystalline containing amorphous materials in terms of stability and desirable hardness, but the smoothness of the intermediate layer surface From the viewpoint of friction, it is preferably amorphous. Crystallinity / amorphous property can be determined by the presence or absence of a point or a line in a diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement. Amorphousness can also be determined by the absence of a sharp peak specific to the diffraction angle even by X-ray diffraction spectrum measurement.

  Various dopants can be added to the intermediate layer 5 in order to control the conductivity type and the conductivity. When the conductivity of the intermediate layer 5 is controlled to n-type, for example, one or more elements selected from Si, Ge, and Sn can be used, and when controlled to p-type, for example, Be, One or more elements selected from Mg, Ca, Zn, and Sr can be used. Further, such an intermediate layer 5 which is not usually doped has many n-types, and an element used for p-type conversion can be used in order to further increase the dark resistance.

The intermediate layer 5 of the present invention has a bond defect, a dislocation defect, a grain boundary defect, etc. in its internal structure regardless of whether the crystallinity / non-crystallinity is microcrystalline, polycrystalline or amorphous. Tend to be included. For this reason, hydrogen and / or a halogen element may be contained in the semiconductor film in order to inactivate these defects. Hydrogen and halogen elements in the intermediate layer are taken into bond defects, etc., which eliminates reactive sites and performs electrical compensation, thereby suppressing traps related to carrier diffusion and movement in the semiconductor film. Is done.
When the intermediate layer 5 as described above is provided below the surface layer 3 of the photoconductor, the residual potential on the surface of the photoconductor due to the internal accumulation of charges when charging and exposure are repeated and the cycle up thereof are increased. And charging characteristics can be further stabilized.

  Although the details of the method for forming the intermediate layer 5 will be described later, the intermediate layer 5 in the present invention is obtained, for example, by a reaction between a compound containing gallium and a compound containing nitrogen or oxygen. When the substrate temperature is from room temperature to 100 ° C., the reaction is preferably caused by using plasma. Compounds containing these elements may be introduced into the plasma at the same time, or compounds containing gallium may be introduced and decomposed downstream of the non-film forming reactive plasma containing nitrogen or oxygen to decompose nitrogen or oxygen on the substrate. You may make it react with oxygen. It is preferable to use the following surface layer manufacturing method because continuous film formation is achieved.

The formed intermediate layer 5 may be an insulating layer, but in this case, the thickness of the intermediate layer needs to be determined from the relationship with the residual potential. In the case of a semiconductive layer, the volume resistivity is preferably in the range of 10 ⁺⁸ to 10 ⁺¹³ Ωcm so as not to interfere with the formation of the electrostatic latent image.
In addition, it is preferable that the thickness of the intermediate | middle layer 5 shall be the range of 0.01-1 micrometer, More preferably, it is the range of 0.02-0.7 micrometer.

(Surface layer)
The surface layer 3 in the present invention is a layer formed on the intermediate layer and containing a group 13 element and at least one of nitrogen and oxygen as in the intermediate layer.
The surface layer 3 is a group 13 oxide containing a group 13 element, nitrogen or oxygen, a group 13 nitride semiconductor, etc., and has high hardness and excellent transparency. Similarly to the intermediate layer 5, when oxygen is included, it has excellent oxidation resistance even in oxygen in the atmosphere or in an oxidizing atmosphere, and changes in physical properties over time are extremely small. Further, a semiconductor film having such a composition can be formed on a photosensitive layer containing an organic material by using a method for producing a surface layer described later.

Since the surface layer 3 in the present invention is a layer containing a group 13 element and at least one of nitrogen and oxygen like the intermediate layer 5, the surface layer 3 is fundamental except that the formation conditions and the layer thickness of the layer are different. The properties are the same as those described in the intermediate layer.
Examples of the compound contained in the surface layer 3 include a compound containing a group 13 element and oxygen, a compound containing a group 13 element and nitrogen, and a compound containing a group 13 element, oxygen and nitrogen.

When the surface layer 3 contains a group 13 element and oxygen, the oxygen content is preferably more than 15 atomic%. When the oxygen content is 15 atomic% or less, the semiconductor film becomes unstable in an oxygen-containing atmosphere, and hydroxyl groups are generated by oxidation. Therefore, physical properties such as electrical characteristics and mechanical characteristics change over time. May cause. In addition, the electric resistance is lowered and the electrostatic latent image cannot be held.
From the viewpoint of ensuring oxidation resistance, it is preferable that the oxygen content is large. However, since the number of molecular bonds between elements in the surface layer film is two-dimensionally arranged, the hardness is insufficient. It may become a fragile film. In the case of forming only from a group 13 element and oxygen, if it is 15 atomic% or less, the electric resistance is low and the electrostatic latent image cannot be retained.

  Further, the oxygen content in the surface layer is more preferably 28 atomic% or more, and further preferably 37 atomic% or more. In practice, the oxygen content is preferably 65 atomic% or less. Even in this case, the nitrogen content in the surface layer is preferably 1 atomic% or more. The surface layer may contain 1 atomic% or more of nitrogen.

  The content of elements such as group 13 elements and oxygen on the outermost surface of the surface layer can be determined by XPS (X-ray photoelectron spectroscopy). For example, it can be measured by using JPS9010MX manufactured by JEOL Ltd. as an XPS measuring apparatus, using an MgKα ray as an X-ray source, and irradiating at 10 kV, 20 mA. In this case, the photoelectron is measured in steps of 1 eV, and the element content is 3d5 / 2 for Ga element, 1s for O, and 1s for N, and obtained from the area intensity of the spectrum and the sensitivity factor. be able to. Note that Ar ion etching is performed at 500 V for about 10 seconds before measurement.

On the other hand, when the surface layer 3 contains a group 13 element and nitrogen, the film thickness of the surface layer 3 is 0.01 μm or more and less than 5 μm, and the center line average roughness (Ra) of the formed surface is 0.1 μm. The following is preferable.
When the center average roughness (Ra) of the surface exceeds 0.1 μm, a cleaning failure due to a blade or a brush occurs in the cleaning process in the electrophotographic apparatus (image forming apparatus), and the toner remains on the surface. Since the charging, developing process, and transfer process are performed, the resolution is lowered, the image density is further lowered, and image unevenness and ghost are likely to occur. Naturally, when the center average roughness (Ra) exceeds 0.1 μm, the lower photosensitive layer 2 is damaged, and thus the sensitivity may be lowered and the remaining power may be increased.
The center average roughness (Ra) of the surface is preferably 0.07 μm or less, and more preferably 0.05 μm or less.

On the other hand, when the thickness of the surface layer 3 is less than 0.01 μm, it is easily affected by the photosensitive layer 2 and the mechanical strength is insufficient. On the other hand, when the thickness is 5 μm or more, the residual potential increases due to repeated charging and exposure, and mechanical internal stress on the photosensitive layer increases, which may cause peeling or cracking.
The thickness of the surface layer is preferably in the range of 0.03 to 3 μm, more preferably in the range of 0.05 to 2 μm.

In addition, the centerline average roughness (Ra) of the surface uses a surface roughness shape measuring device Surfcom 550A manufactured by Tokyo Seimitsu Co., Ltd., with a cutoff value of 75%, a measuring distance of 1.0 mm, and a scanning speed of 0.12 mm / sec. Are measured in the axial direction at 10 arbitrary positions on the photoconductor and averaged.
The thickness of the surface layer is a cross-sectional photograph of a semiconductor film taken with a stylus type step difference measuring device (manufactured by Tokyo Seimitsu Co., Ltd., surface roughness meter) and a scanning electron microscope (manufactured by Hitachi, S-400). Was measured in combination.

Specifically, as the group 13 element contained in the surface layer 3, at least one element selected from B, Al, Ga, and In can be used, and two or more elements selected from these elements can be used. Combinations of elements can also be used.
In this case, the combination of the contents in the surface layer of these atoms is not limited, but among the above four elements, in the case of In, absorption is in the visible light region, and elements other than In are in the visible light region. Since there is no absorption, it is possible to arbitrarily adjust the sensitive wavelength range of the surface layer film to light by appropriately selecting the group 13 element to be used. For example, when the semiconductor film of the present invention is used as a surface layer of a photoconductor, an element that absorbs as much light as possible with respect to the exposure wavelength and the erase wavelength of an electrophotographic apparatus equipped with this photoconductor is used. It is necessary to select.

The atomic ratio of nitrogen and / or oxygen and the group 13 element in the surface layer 3 is preferably 0.5: 1 to 3: 1. If it is outside this range, there are few portions where tetrahedral bonds are formed, and it becomes ionic molecule-bonded, so that sufficient chemical stability and hardness cannot be obtained.
The composition in the thickness direction of the surface layer 3 may be uniform, but as long as it contains a group 13 element and oxygen, the composition has a gradient structure in the thickness direction of the film or has a multilayer structure It may be. Further, it has a nitrogen concentration distribution in the thickness direction of the surface layer 3 and may increase toward the substrate side, and the oxygen concentration distribution may decrease toward the substrate side. The concentration distribution may decrease toward the substrate side, and the oxygen concentration distribution may increase toward the substrate side.

  The surface layer 3 may contain only a group 13 element and oxygen and / or nitrogen. However, when the surface layer and the intermediate layer made of only oxygen and the group 13 element are made only of oxygen and the group 13 element. Requires that the interface between the surface layer and the intermediate layer is discontinuous, and the oxygen concentration in the intermediate layer is lower than that in the surface layer. Furthermore, the surface layer 3 may contain a fourth element such as hydrogen as necessary in addition to the group 13 element, oxygen, and nitrogen, and particularly preferably contains hydrogen. In this case, hydrogen compensates for dangling bonds and structural defects generated by the combination of the group 13 element, nitrogen, and oxygen, thereby increasing electrical stability, chemical stability, and mechanical stability. In addition to high hardness and transparency, high water repellency and a low friction coefficient on the surface layer film surface can be obtained.

Here, when hydrogen is contained in the surface layer film, the hydrogen content in the surface layer film is preferably in the range of 0.1 atomic% to 40 atomic%, and in the range of 0.5 to 30 atomic%. The inside is more preferable.
When the hydrogen content is less than 0.1 atomic%, structural disturbances remain built in the film, which may cause electrical instability and insufficient mechanical characteristics. In addition, when it exceeds 40 atomic%, the probability of hydrogen bonding to two or more atoms of group 13 elements and nitrogen atoms increases, and a three-dimensional structure cannot be maintained, and hardness and chemical stability (especially water resistance) Etc. may be insufficient.
The amount of hydrogen contained in the surface layer film is 0.1 atomic% or more and 50 atomic% or less with respect to the entire two main elements (group 13 element and oxygen or group 13 element and nitrogen) constituting the surface layer film. Is preferable, and the range of 1 atomic% to 40 atomic% is more preferable.

The amount of hydrogen can be determined by hydrogen forward scattering (hereinafter sometimes referred to as “HFS”) as follows (the same applies to the measurement of the amount of hydrogen in the intermediate layer).
HFS used NEC 3SDH Pelletron as an accelerator, CE & A RBS-400 as an end station, and 3S-R10 as a system. For the analysis, the CE & A HYPRA program was used. The measurement conditions of HFS are as follows.
-He ++ ion beam energy: 2.275 eV
Detection angle: Grazing Angle 30 ° with respect to 160 ° incident beam

The HFS measurement can pick up the hydrogen signal scattered in front of the sample by setting the detector at 30 ° to the He ++ ion beam and the sample at 75 ° from the normal. At this time, the detector is preferably covered with a thin aluminum foil to remove He atoms scattered together with hydrogen. The quantification is performed by comparing the hydrogen counts of the reference sample and the sample to be measured after normalization with the stopping power.
As a reference sample, a sample obtained by ion implantation of H into Si and muscovite were used. It is known that muscovite has a hydrogen concentration of about 6.5 atomic%. Note that H adsorbed on the outermost surface can be obtained by subtracting the amount of H adsorbed on the clean Si surface.

  The amount of hydrogen in the layer can also be estimated from the intensity of a group 13 element-hydrogen bond or NH bond by infrared absorption spectrum measurement. In the case of measuring by an infrared absorption spectrum, the film may be formed on an infrared transmission substrate under the same conditions as those at the time of film formation, or may be peeled off from the photoreceptor and measured as a KBr tablet. In the case where the photosensitive layer is an organic photoreceptor, the residue can be used by dissolving in an organic solvent. In the case of amorphous silicon, the surface may be scraped off or the whole may be peeled off.

For this infrared absorption spectrum measurement, Perkin Elmer's Sectum One Fourier Transform Infrared Absorption Measuring Instrument System B S / N ratio 30000: 1, resolution 4 cm ⁻¹ was used. A sample deposited on a 10 mm × 10 mm silicon wafer was measured after being placed on a sample stage with a beam condenser. For reference, a silicon wafer that was not deposited was used.
For example the half width of GaN absorption to the intersection and the peak apex of the line drawn perpendicularly from the GaN absorption peak linear extrapolated to a lower wavenumber side by connecting the valley of the absorption of 1100 cm ^-1 and 800 cm ^-1 as a baseline As the total absorption intensity, the line width in the lateral direction of absorption at this half intensity position was defined as the half-value width.

The surface layer may contain carbon, but the content in this case is preferably 15 atomic% or less. If the carbon content exceeds 15 atomic%, carbon is present in the surface layer film as —CH ₂ , —CH ₃ , so that the amount of hydrogen contained in the surface layer film increases. Chemical stability in the atmosphere may be insufficient.

The content of elements such as group 13 elements and nitrogen, oxygen, carbon, etc. in the surface layer can be determined by Rutherford backscattering (RBS) including distribution in the film thickness direction as described above (the intermediate The same applies to the measurement of group 13 elements in the layer).
RBS used NEC 3SDH Pelletron as an accelerator, CE & A RBS-400 as an end station, and 3S-R10 as a system. The analysis used the CE & A HYPRA program.
The RBS measurement conditions are: He ++ ion beam energy is 2.275 eV, detection angle is 160 °, and Grazing Angle is about 109 ° with respect to the incident beam.

Specifically, the RBS measurement was performed as follows.
First, a He ++ ion beam is incident on the sample perpendicularly, a detector is set at 160 ° with respect to the ion beam, and the backscattered He signal is measured. The composition ratio and the film thickness are determined from the detected energy and intensity of He. In order to improve the accuracy of obtaining the composition ratio and the film thickness, the spectrum may be measured at two detection angles. Accuracy can be improved by measuring and cross-checking at two detection angles with different depth resolution and backscattering dynamics.
The number of He atoms back-scattered by the target atom is determined only by three factors: 1) the atomic number of the target atom, 2) the energy of the He atom before scattering, and 3) the scattering angle. The density is assumed by calculation from the measured composition, and this is used to calculate the film thickness. The density error is within 20%.

Even when the intermediate layer and the surface layer are continuously formed on the photosensitive layer as in the present invention, the elemental composition of each of the surface layer and the intermediate layer is obtained without destroying the surface layer portion by the above measurement method. Can be measured.
The content of each element in the entire surface layer can be measured by secondary electron mass spectrometry or XPS (X-ray photoelectron spectroscopy).

Whether the surface layer 3 is crystalline or non-crystalline is not particularly limited, but may be microcrystalline, polycrystalline, or amorphous.
The surface layer film may be amorphous containing microcrystals or microcrystalline / polycrystalline containing amorphous because of stability and hardness, but the surface layer film surface smoothness and friction From this point, it is preferably amorphous. Crystallinity / amorphous property can be determined by the presence or absence of a point or a line in a diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement. Amorphousness can also be determined by the absence of a sharp peak specific to the diffraction angle even by X-ray diffraction spectrum measurement.

  Various dopants can be added to the surface layer 3 in order to control the conductivity type and the conductivity. When the conductivity of the surface layer film is controlled to n-type, for example, one or more elements selected from Si, Ge, and Sn can be used, and when controlled to p-type, for example, Be, One or more elements selected from Mg, Ca, Zn, and Sr can be used. Further, such a surface layer which is not usually doped has many n-types, and an element used for p-type conversion can be used in order to further increase the dark resistance.

  The surface layer 3 in the present invention has a bond defect, a dislocation defect, a crystal grain boundary defect, etc. in its internal structure regardless of whether the crystallinity / non-crystallinity is microcrystalline, polycrystalline or amorphous. Tend to be included. For this reason, hydrogen and / or a halogen element may be contained in the surface layer film in order to inactivate these defects. Hydrogen and halogen elements in the surface layer are incorporated into bonding defects, etc., which eliminates reactive sites and performs electrical compensation. Therefore, traps related to the diffusion and movement of carriers in the surface layer film are generated. It is suppressed.

Next, preferable characteristics and the like of the surface layer 3 other than the above-described composition will be briefly described.
As described above, the surface layer 3 may be either amorphous or crystalline. However, in order to improve the adhesion to the photosensitive layer (or the intermediate layer) and to improve the sliding of the surface of the photosensitive member, the surface layer 3 is used. 3 is preferably amorphous. Further, the lower layer (photosensitive layer side) of the surface layer 3 may be microcrystalline, and the upper layer (photosensitive member surface side) may be amorphous.

  The surface layer 3 may be one in which charges are injected into the surface layer during charging. In this case, charges must be trapped between the surface layer 3 and the photosensitive layer 2. Further, electric charges may be trapped on the surface of the surface layer 3. For example, when the photosensitive layer 2 is a function-separated type as shown in FIG. 1, if the surface layer 3 injects electrons with negative charge, the surface of the charge transport layer on the surface layer side may function as a charge trap. Alternatively, the intermediate layer 5 may function as charge injection blocking and trapping. The same applies to the case of positive charging.

  The thickness of the surface layer 3 is preferably in the range of 0.1 μm to 1 μm. If the thickness is 0.1 μm or less, it is easily affected by the photosensitive layer, and the mechanical strength may be insufficient. On the other hand, when the thickness is 1 μm or more, the residual potential increases due to repeated charging and exposure, and mechanical internal stress on the photosensitive layer increases, which may cause peeling or cracking.

The surface layer 3 may also function as a charge injection blocking layer or a charge injection layer. In this case, as described above, the surface layer 3 can function as a charge injection blocking layer or a charge injection layer by adjusting the conductivity type of the surface layer film to n-type or p-type.
When the surface layer 3 also functions as a charge injection layer, charges are trapped on the surface of the intermediate layer 5 and the photosensitive layer 2 (surface on the surface layer side). In the case of negative charging, the n-type surface layer 3 functions as a charge injection layer, and the p-type surface layer functions as a charge injection blocking layer. In the case of positive charging, the n-type surface layer 3 functions as a charge injection blocking layer, and the p-type surface layer functions as a charge injection layer.
In order to maintain the electrostatic latent image, a high resistance i-type surface layer film may be formed as the surface layer.

(Formation of surface layer and intermediate layer)
Next, a method for forming the surface layer and the intermediate layer in the present invention will be described. For the formation of the surface layer and the intermediate layer, a known vapor deposition method such as a plasma CVD (Chemical Vapor Deposition) method, a metal organic vapor phase epitaxy method, a molecular beam epitaxy method, vapor deposition or sputtering can be used. It is preferable to use a phase growth method.

In this case, the substance containing nitrogen and / or the substance containing oxygen is used as an active species by activating means for activating the substance containing nitrogen and the substance containing oxygen into an energy state or an excited state necessary for the reaction, It is preferable to form the surface layer and the intermediate layer in the present invention on the photosensitive layer by reacting the active species with an organometallic compound containing a group 13 element that is not activated.
Accordingly, when the photosensitive layer contains an organic material, the surface layer and the intermediate layer having the above-described characteristics can be formed as the surface layer of the photosensitive member without causing thermal damage to the photosensitive layer. . In forming the surface layer and the intermediate layer, the surface of the photosensitive layer may be previously cleaned with plasma.

Note that the formation of the surface layer and the intermediate layer as described above is usually performed by using a substance containing nitrogen, a substance containing oxygen, a gas composed of an organometallic compound containing a group 13 element, or a gas obtained by vaporizing them. In the reaction chamber (film formation chamber) in which (the photosensitive layer is formed on the conductive substrate) is disposed, the gas containing each component is supplied to the reaction chamber and the reaction finished gas It is carried out while exhausting from the reaction chamber. From such a viewpoint, it is preferable to introduce an organometallic compound containing a group 13 element downstream of an activating means for activating a substance containing nitrogen and a substance containing oxygen.
As a result, the substance containing nitrogen and the substance containing oxygen activated on the upstream side of the position where the organometallic compound containing the group 13 element is introduced merge on the downstream side of the activating means, and thus are activated. It is possible to react an organometallic compound containing no group 13 element with a substance containing activated nitrogen and / or a substance containing oxygen.

  In the present invention, the surface layer and the intermediate layer are formed when the intermediate layer is formed on the photosensitive layer, for example, when the photosensitive layer of the photoreceptor contains an organic charge generating material or an organic material such as a binder resin. The maximum temperature of the substrate surface is preferably 100 ° C. or less, preferably 50 ° C. or less, and the maximum temperature of the substrate surface is preferably closer to room temperature. When the temperature exceeds 100 ° C., the base material may be deformed or the physical properties may be deteriorated due to decomposition of the organic material contained in the photosensitive layer.

Hereinafter, the method for forming the surface layer and the intermediate layer will be described in more detail by taking as an example the case of forming the intermediate layer and the surface layer of the photoreceptor.
FIG. 3 is a schematic diagram showing an example of a film forming apparatus used for forming the intermediate layer and the surface layer of the photoreceptor of the present invention. FIG. 3A is a schematic view when the film forming apparatus is viewed from the side. A cross-sectional view is shown, and FIG. 3B is a schematic cross-sectional view taken along line A1-A2 of the film formation apparatus shown in FIG. In FIG. 3, 10 is a film forming chamber, 11 is an exhaust port, 12 is a substrate rotating unit, 13 is a substrate holder, 14 is a substrate, 15 is a gas introducing unit, and 16 is a gas introduced from the gas introducing unit 15. A shower nozzle having an opening, 17 is a plasma diffusion unit, 18 is a high-frequency power supply unit, 19 is a flat plate electrode, 20 is a gas introduction tube, and 21 is a high-frequency discharge tube unit.

In the film forming apparatus shown in FIG. 3, an exhaust port 11 connected to a vacuum exhaust apparatus (not shown) is provided at one end of the film forming chamber 10, and the side of the film forming chamber 10 where the exhaust port 11 is provided. On the opposite side, a plasma generator comprising a high-frequency power supply unit 18, a plate electrode 19 and a high-frequency discharge tube unit 21 is provided.
This plasma generator is disposed in a high-frequency discharge tube portion 21, a high-frequency discharge tube portion 21, a flat plate electrode 19 provided with a discharge surface on the exhaust port 11 side, and disposed outside the high-frequency discharge tube portion 21. The high-frequency power supply unit 18 is connected to the surface of the electrode 19 opposite to the discharge surface. The high-frequency discharge tube portion 21 is connected to a gas introduction tube 20 for supplying gas into the high-frequency discharge tube portion 21, and the other end of the gas introduction tube 20 is a first not shown. Connected to the gas supply.

  Note that the plasma generator shown in FIG. 4 may be used instead of the plasma generator provided in the deposition apparatus shown in FIG. FIG. 4 is a schematic diagram showing another example of the plasma generating apparatus that can be used in the film forming apparatus shown in FIG. 3, and is a side view of the plasma generating apparatus. In FIG. 4, 22 represents a high frequency coil, 23 represents a quartz tube, and 20 is the same as that shown in FIG. This plasma generator comprises a quartz tube 23 and a high-frequency coil 22 provided along the outer peripheral surface of the quartz tube 23. One end of the quartz tube 23 is formed with a film forming chamber 10 (not shown in FIG. 4). It is connected. The other end of the quartz tube 23 is connected to a gas introduction tube 20 for introducing gas into the quartz tube 23.

A rod-shaped shower nozzle 16 substantially parallel to the discharge surface is connected to the discharge surface side of the flat plate electrode 19, and one end of the shower nozzle 16 is connected to a gas introduction tube 15. A second gas supply source (not shown) provided outside the film forming chamber 10 is connected.
In addition, a substrate rotating unit 12 is provided in the film forming chamber 10 so that the cylindrical substrate 14 faces the longitudinal direction of the shower nozzle and the axial direction of the substrate 14 substantially in parallel. It can be attached to the base rotating part 12 via the holder 13. In film formation, the base member 14 can be rotated in the circumferential direction by rotating the substrate rotating unit 12. In addition, as the base material 14, a photoconductor previously laminated up to the photosensitive layer, or a photoconductor laminated up to the intermediate layer on the photosensitive layer is used.

Formation of the surface layer and the intermediate layer (hereinafter, these may be collectively referred to as “surface layer etc.”) can be carried out, for example, as follows. First, N ₂ gas, H ₂ gas, He gas, and oxygen gas are introduced into the high-frequency discharge tube 21 from the gas introduction tube 20, and a 13.56 MHz radio wave is applied from the high-frequency power supply unit 18 to the plate electrode 19. Supply. At this time, the plasma diffusion portion 17 is formed so as to spread radially from the discharge surface side of the flat plate electrode 19 to the exhaust port 11 side. Here, the four types of gases introduced from the gas introduction pipe 20 flow through the film forming chamber 10 from the plate electrode 19 side to the exhaust port 11 side. The plate electrode 19 may be one in which the electrode is surrounded by a ground shield.
Next, trimethylgallium gas diluted with hydrogen as a carrier gas is introduced into the film forming chamber 10 through the gas inlet tube 15 and the shower nozzle 16 located downstream of the flat plate electrode 19 serving as the activating means. A non-single-crystal film containing gallium, nitrogen, and oxygen can be formed on the surface of the base material 14.

The formation temperature of the surface layer and the like at the time of film formation is not particularly limited, but when an amorphous silicon photoconductor is manufactured, the surface temperature of the cylindrical substrate 14 may be formed within a range of 50 ° C. to 350 ° C. Preferably, when producing an organic photoreceptor, the surface of the cylindrical substrate 14 is preferably formed at a temperature in the range of 20 ° C to 100 ° C.
In the case of producing an organic photoreceptor, the temperature of the surface of the substrate 14 during film formation of the surface layer or the like is preferably 100 ° C. or less, more preferably 80 ° C. or less, and particularly preferably 50 ° C. or less. Even if the temperature of the surface of the substrate 14 is 100 ° C. or less at the beginning of film formation, if the temperature becomes higher than 150 ° C. due to plasma, the photosensitive layer may be damaged by heat. It is preferable to control the surface temperature of the base material 14 in consideration.

The temperature of the surface of the base material 14 may be controlled by heating and / or cooling means (not shown in the drawing), or may be left to a natural temperature increase during discharge. When heating the base material 14, a heater may be installed outside or inside the base material 14. When the substrate 14 is cooled, a cooling gas or liquid may be circulated inside the substrate 14.
In order to avoid an increase in the temperature of the surface of the base material 14 due to electric discharge, it is effective to adjust a high energy gas flow hitting the surface of the base material 14. In this case, conditions such as the gas flow rate, discharge output, and pressure are adjusted so as to achieve the required temperature.

As the gas containing a group 13 element, an organic metal compound containing indium or aluminum or a hydride such as diborane may be used instead of trimethylgallium gas, and two or more of these may be mixed.
For example, in the initial stage of formation of the surface layer or the like, a film containing nitrogen and indium is formed on the base material 14 by introducing trimethylindium into the film formation chamber 10 through the gas introduction tube 15 and the shower nozzle 16. If the film is formed, this film is generated when the film is continuously formed, and it is possible to absorb ultraviolet rays that deteriorate the photosensitive layer. For this reason, damage to the photosensitive layer due to generation of ultraviolet rays during film formation can be suppressed.

In addition, a dopant can be added to the surface layer or the like in order to control the conductivity type. As a dopant doping method at the time of film formation, SiH ₃ and SnH ₄ are used for n-type, and biscyclopentadienyl magnesium, dimethyl calcium, dimethyl strontium, dimethyl zinc, diethyl zinc, etc. are used for p-type. Can be used in the gas state. In order to dope the dopant element into the surface layer, a known method such as a thermal diffusion method or an ion implantation method may be employed.
Specifically, a surface layer of any conductivity type such as n-type or p-type is introduced by introducing a gas containing at least one dopant element into the film forming chamber 10 through the gas introduction pipe 15 and the shower nozzle 16. Can be obtained.

Note that when an organometallic compound containing a hydrogen atom is used as a supply material for the group 13 element and a surface layer mainly including a group 13 atom, a nitrogen atom, and oxygen is formed, active hydrogen is contained in the film formation chamber 10. Preferably it is present. The active hydrogen may be supplied from hydrogen atoms used as a carrier gas or hydrogen atoms contained in an organometallic compound.
For example, in the film forming apparatus as shown in FIG. 3, when hydrogen gas and nitrogen gas or oxygen gas are introduced into the film forming apparatus from different positions, the activated state of the hydrogen gas and the nitrogen gas or oxygen gas A plurality of plasma generators may be provided so that the gas activation state can be independently controlled. On the other hand, in terms of simplification of the apparatus, a gas containing simultaneously nitrogen atoms and hydrogen atoms such as NH ₃ is used as a supply material of hydrogen and nitrogen or oxygen gas, or nitrogen gas and hydrogen gas are used. It is preferable to use a gas mixed with or a gas containing oxygen and hydrogen at the same time, such as H ₂ O, to activate it with plasma.

  Further, when a rare gas such as helium or hydrogen is used in combination as a carrier gas, the etching effect of the film grown on the surface of the base material 14 by a rare gas such as helium and hydrogen can be used even at a low temperature of 100 ° C. or lower. And an amorphous group 13 element with less hydrogen and nitrogen and / or oxygen can be formed.

By the method as described above, activated hydrogen, nitrogen, oxygen, rare gas and group 13 atom are present in the vicinity of the surface of the substrate 14, and further, the activated rare gas or hydrogen is converted into an organometallic compound. It has the effect of desorbing hydrogen of hydrocarbon groups such as methyl groups and ethyl groups as molecules. Therefore, on the surface of the base material 14, a surface layer made of a hard film having a low hydrogen content and forming a three-dimensional bond of nitrogen and / or oxygen and a group 13 element is formed at a low temperature.
Such a hard film is transparent because Ga, N, and O form sp3 bonds like carbon atoms constituting diamond, unlike sp2 bondable carbon atoms contained in silicon carbide. Furthermore, the film is transparent and hard, and the film surface has water repellency and low friction.

The plasma generating means of the film forming apparatus shown in FIG. 3 uses a high-frequency oscillation device, but is not limited to this. For example, a microwave oscillation device, an electrocyclotron resonance method, or a helicon plasma is used. A type of apparatus may be used. In the case of a high-frequency oscillation device, it may be inductive or capacitive.
Furthermore, two or more of these devices may be used in combination, or two or more of the same types of devices may be used. In order to prevent the temperature of the surface of the base material 14 from rising due to plasma irradiation, a high-frequency oscillation device is preferable, but a device for preventing heat irradiation may be provided.

  When two or more types of different plasma generators (plasma generating means) are used, it is necessary to be able to generate discharges simultaneously at the same pressure. In addition, a pressure difference may be provided between the discharge region and the film formation region (the portion where the base is installed). These apparatuses may be arranged in series with respect to the gas flow formed in the film forming apparatus from the part where the gas is introduced to the part where the gas is discharged. You may arrange | position so that it may oppose.

For example, when two types of plasma generating means are installed in series with respect to the gas flow, the film forming apparatus shown in FIG. 3 is taken as an example, and a discharge is caused in the film forming chamber 10 using the shower nozzle 16 as an electrode. 2 can be used as a plasma generator. In this case, a high-frequency voltage can be applied to the shower nozzle 16 via the gas introduction part 15 to cause discharge in the film forming chamber 10 using the shower nozzle 16 as an electrode. Alternatively, instead of using the shower nozzle 16 as an electrode, a cylindrical electrode is provided between the base material 14 in the film forming chamber 10 and the plasma generation region 19, and film formation is performed using this cylindrical electrode. It is also possible to cause discharge in the chamber 10.
In addition, when two different types of plasma generators are used under the same pressure, for example, when using a microwave oscillator and a high-frequency oscillator, the excitation energy of the excited species can be greatly changed, and the film quality can be controlled. It is valid. Moreover, you may perform discharge near atmospheric pressure. When discharging near atmospheric pressure, it is desirable to use He as a carrier gas.

In forming the surface layer and the like, other than the above-described methods, a normal metal organic vapor phase epitaxy method or a molecular beam epitaxy method can be used. Use of active hydrogen or active oxygen is effective for lowering the temperature. In this case, as the nitrogen raw material, a gas or liquid such as N ₂ , NH ₃ , NF ₃ , N ₂ H ₄ , methyl hydrazine, or the like, or a gas bubbled with a carrier gas can be used. As the oxygen source, oxygen, H ₂ O, CO, CO ₂ , NO, N ₂ O, or the like can be used.

  In the present invention, the intermediate layer and the surface layer are formed by placing a base material 14 having a photosensitive layer formed on a conductive substrate in the film forming chamber 10 and introducing mixed gases having different compositions to form the intermediate layer and the surface layer. The surface layer may be formed continuously or may be formed up to the intermediate layer and then placed again in the film forming chamber 10 as the base material 14.

As film formation conditions, for example, when discharging is performed by high-frequency discharge, it is preferable that the frequency is in the range of 10 kHz to 50 MHz in order to perform high-quality film formation at a low temperature. Further, the output depends on the size of the substrate, but is preferably in the range of 0.01 to 0.2 W / cm ² with respect to the surface area of the substrate. The rotation speed of the substrate is preferably in the range of 0.1 rpm to 500 ppm.
The film formation conditions for the intermediate layer and the surface layer may be the same, but for example, since the intermediate layer is formed at a low temperature, the output may be slightly lower, and the surface layer may be formed with a higher output.

  Regarding the intermediate layer and the surface layer formed as described above, the combined thickness of these layers is 0.1 μm or more and less than 5 μm, and is in the range of 0.5 to 10% of the layer thickness of the photosensitive layer described later. Preferably there is. Basically, in the photosensitive member, the surface layer portion is less susceptible to the strain due to stress when the photosensitive layer is thicker than the surface layer portion.

When the layer thickness is larger than 10% of the photosensitive layer thickness, the influence of the distortion of the photosensitive layer as a whole increases, and cracks may occur in the surface layer portion. Further, the residual potential becomes higher than the sum of the individual residual potentials. If it is less than 0.5%, the film thickness of the surface layer portion including the durability may be insufficient.
The layer thickness ratio is more preferably in the range of 0.7 to 7%.

(Conductive substrate and photosensitive layer)
The photoreceptor of the present invention is not particularly limited as long as the layer structure is such that a photosensitive layer, an intermediate layer, and a surface layer are laminated in this order on a conductive substrate, and is necessary between the conductive substrate and the photosensitive layer. Depending on the case, an undercoat layer or the like may be provided. Further, the photosensitive layer may be two or more layers, and further may be a function separation type. Further, the photoreceptor of the present invention may be a so-called amorphous silicon photoreceptor in which the photosensitive layer contains silicon atoms.

  In the case of an amorphous silicon photoreceptor, if the surface layer or the like according to the present invention is used as a surface layer portion, image blur at high humidity can be prevented, and both durability and high image quality can be achieved. In particular, the photosensitive layer is preferably a so-called organic photoreceptor containing an organic material such as an organic photosensitive material. In the case of an organic photoreceptor, wear tends to occur. However, if the surface layer or the like in the present invention is used for the surface layer portion, wear can be suppressed.

First, an outline of a preferred configuration when the photoreceptor of the present invention is an organic photoreceptor will be described.
The organic polymer compound forming the photosensitive layer may be thermoplastic or thermosetting, or may be formed by reacting two types of molecules. The intermediate layer provided between the photosensitive layer and the surface layer has the properties of the surface layer and the photosensitive layer (in the case of the function separation type, charge transport) from the viewpoints of hardness, expansion coefficient, elasticity adjustment, and adhesion improvement. Those exhibiting intermediate characteristics with respect to both physical properties of the layer) are preferred. The intermediate layer may function as a layer that traps charges.

  In the case of an organic photoreceptor, the photosensitive layer may be a function-separated type that is divided into a charge generation layer and a charge transport layer as shown in FIG. 1, or may be a function-integrated type as shown in FIG. In the case of the function separation type, a charge generation layer may be provided on the surface side of the photoreceptor, or a charge transport layer may be provided on the surface side.

When a surface layer or the like is formed on the photosensitive layer by the above-described method, the surface layer or the like is formed on the surface of the photosensitive layer in order to prevent the photosensitive layer from being decomposed by irradiation with short-wave electromagnetic waves other than heat. A short wavelength light absorption layer such as ultraviolet rays may be provided in advance. In addition, a layer having a small band gap can be formed first in the initial stage of forming the surface layer or the like so that the short wavelength light is not irradiated onto the photosensitive layer. As a composition of such a layer having a small band gap provided on the photosensitive layer side, for example, the group 13 element ratio including In is preferably Ga _X In _(1-X) (0 ≦ X ≦ 0.99). It is. The same conditions as described above are used for oxygen and nitrogen.

In addition, a layer containing an ultraviolet absorber (for example, a layer formed by coating a layer dispersed in a polymer resin) may be provided on the surface of the photosensitive layer.
In this way, by providing a protective layer on the surface of the photoconductor before forming the surface layer, etc., ultraviolet rays when forming the surface layer, etc., corona discharge when the photoconductor is used in the image forming apparatus, It is possible to prevent the photosensitive layer from being affected by short-wavelength light such as ultraviolet rays from various light sources.

Next, an outline of a preferable configuration when the photoconductor of the present invention is an amorphous silicon photoconductor will be described.
The amorphous silicon photoreceptor may be a positively charged photoreceptor or a negatively charged photoreceptor. An undercoating layer for preventing charge injection and improving adhesion can be formed on a conductive substrate, and then a photoconductive layer and a surface layer can be used. For the surface layer, an intermediate layer may be provided on the surface of the photosensitive layer, and a surface layer may be further provided on the surface, or a surface layer may be provided directly on the surface of the photosensitive layer.
The uppermost layer (surface layer side layer) of the photosensitive layer may be p-type amorphous silicon or n-type amorphous silicon, and an intermediate layer (charge injection blocking) between the photosensitive layer and the surface layer. as layers), for _{example, Si X O 1-X:} H, Si X N 1-X: H, Si X C 1-X: H, amorphous carbon layer may be formed.

  Next, the details of the conductive substrate and the photosensitive layer constituting the electrophotographic photosensitive member of the present invention and the details of the undercoat layer and the protective layer provided as necessary will be described. The case of an organic photoreceptor having the above will be described.

-Conductive substrate-
Conductive substrates include metal drums such as aluminum, copper, iron, stainless steel, zinc, nickel; aluminum, copper, gold, silver, platinum, palladium, titanium, nickel on a substrate such as sheet, paper, plastic, glass, etc. -Deposited metal such as chromium, stainless steel, copper-indium; Deposited conductive metal compound such as indium oxide and tin oxide on the substrate; Laminated metal foil on the substrate; Carbon black Indium oxide, tin oxide-antimony oxide powder, metal powder, copper iodide, and the like are dispersed in a binder resin and applied to the substrate to conduct a conductive treatment. The shape of the conductive substrate may be any of a drum shape, a sheet shape, and a plate shape.

  When a metal pipe base is used as the conductive base, the surface of the metal pipe base may be a raw pipe, but the base surface may be roughened by surface treatment in advance. It is. Such roughening can prevent grain-like density unevenness due to interference light that can be generated inside the photosensitive member when a coherent light source such as a laser beam is used as the exposure light source. Examples of the surface treatment method include mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing and the like.

  In particular, from the viewpoint of improving adhesion to the photosensitive layer and improving film forming properties, it is preferable to use an anodized surface of the aluminum substrate as described below as the conductive substrate.

Hereinafter, a method for producing a conductive substrate having an anodized surface will be described. First, pure aluminum or aluminum alloy (for example, alloy numbers 1000, 3000, and 6000 series aluminum or aluminum alloy defined in JISH4080) is prepared as a substrate. Next, an anodizing process is performed. The anodizing treatment is performed in an acidic bath of chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., and a treatment using a sulfuric acid bath is often used. The anodizing treatment is, for example, sulfuric acid concentration: 10 mass% to 20 mass%, bath temperature: 5 ° C. to 25 ° C., current density: 1 A / dm ^{2 to} 4 A / dm ² and electrolysis voltage: 5 V to 30 V. The treatment time is 5 to 60 minutes, but is not limited thereto.

  The anodized film formed on the aluminum substrate in this way is porous, has high insulating properties, and has a very unstable surface. Therefore, its physical properties change over time after the film is formed. It has become easier. In order to prevent the change of the physical property values, the anodized film is further sealed. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Of these methods, the method of immersing in an aqueous solution containing nickel acetate is most often used.

  On the surface of the anodic oxide film that has been subjected to the sealing treatment in this way, an excessive amount of metal salt or the like attached by the sealing treatment remains. If such metal salts etc. remain excessively on the anodic oxide film of the substrate, not only will the quality of the film formed on the anodic oxide film be adversely affected, but generally low resistance components tend to remain. For this reason, when an image is formed by using this substrate as a photosensitive member, it becomes a cause of background stains.

  Therefore, following the sealing process, an anodic oxide film is cleaned to remove metal salts and the like attached by the sealing process. The cleaning treatment may be performed by cleaning the substrate once with pure water, but the substrate is preferably cleaned by a multi-step cleaning process. At this time, a cleaning liquid that is as clean as possible (deionized) is used as the cleaning liquid in the final cleaning step. Moreover, it is more preferable to perform physical rubbing cleaning using a contact member such as a brush in any one of the multi-step cleaning steps.

  The film thickness of the anodized film on the surface of the conductive substrate formed as described above is preferably in the range of about 3 μm to 15 μm. On the anodized film, there is a layer called a barrier layer along the porous extreme surface of the porous anodized film. The thickness of the barrier layer is preferably in the range of 1 nm to 100 nm in the photoreceptor used in the present invention. As described above, an anodized conductive substrate can be obtained.

  The conductive substrate thus obtained has a high carrier blocking property in the anodized film formed on the substrate by anodization. Therefore, it is possible to prevent point defects (black spots, background stains) that occur when a photoconductor using this conductive substrate is mounted on an image forming apparatus and reversal development (negative / positive development) is performed, It is possible to prevent a current leakage phenomenon from a contact charger that is likely to occur during contact charging. Further, by subjecting the anodized film to a sealing treatment, it is possible to prevent a change in physical property values with time after the preparation of the anodized film. In addition, by washing the conductive substrate after the sealing treatment, metal salts and the like attached to the surface of the conductive substrate can be removed by the sealing treatment, and a photoconductor produced using this conductive substrate is provided. When an image is formed by the image forming apparatus, it is possible to sufficiently prevent the occurrence of background stains.

-Undercoat layer-
Next, the undercoat layer will be described. The material constituting the undercoat layer is acetal resin such as polyvinyl butyral; polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate In addition to polymer resin compounds such as resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atoms, etc. Examples thereof include organometallic compounds.
These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, an organometallic compound containing zirconium or silicon is preferably used because it has a low residual potential and a small potential change due to the environment and a small potential change due to repeated use. In addition, the organometallic compound can be used alone or in combination of two or more, or further mixed with the above-described binder resin.

  As organic silicon compounds (organometallic compounds containing silicon atoms), vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , Γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N Examples include -β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. Among these, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyl Silane coupling agents such as trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferably used.

  Examples of organic zirconium compounds (zirconium-containing organometallic compounds) include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, Zirconium phosphonate, zirconium octoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organotitanium compounds (organometallic compounds containing titanium) include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene. Examples include glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of organoaluminum compounds (aluminum-containing organometallic compounds) include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  Moreover, as a solvent used for the undercoat layer forming coating solution for forming the undercoat layer, known organic solvents, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, methanol, ethanol, n-propanol, Aliphatic alcohol solvents such as iso-propanol and n-butanol, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, tetrahydrofuran, dioxane and ethylene Examples thereof include cyclic or linear ether solvents such as glycol and diethyl ether, and ester solvents such as methyl acetate, ethyl acetate, and n-butyl acetate. These solvents can be used alone or in admixture of two or more. As a solvent that can be used when two or more solvents are mixed, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  The undercoat layer is formed by first preparing an undercoat layer forming coating solution prepared by dispersing and mixing an undercoat layer coating agent and a solvent, and applying the prepared solution to the surface of the conductive substrate. As a coating method for the coating solution for forming the undercoat layer, it is possible to use usual methods such as a dip coating method, a ring coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method. it can. In the case of forming the undercoat layer, it is preferable that the film thickness be in the range of 0.1 μm to 3 μm. By setting the film thickness of the undercoat layer within such a film thickness range, it is possible to prevent an increase in potential due to desensitization and repetition without excessively strengthening the electrical barrier.

  By forming the undercoat layer on the conductive substrate in this way, it is possible to improve wettability when applying and forming a layer formed on the undercoat layer, and as an electrical blocking layer. The function of can be sufficiently fulfilled.

The surface roughness of the undercoat layer formed as described above is 1 / (4n) times the exposure laser wavelength λ used (where n is the refractive index of the layer provided on the outer peripheral side of the undercoat layer) to It is possible to adjust to have a roughness within a range of about 1 time. The surface roughness is adjusted by adding resin particles to the coating solution for forming the undercoat layer. As a result, when a photoreceptor prepared by adjusting the surface roughness of the undercoat layer is used in an image forming apparatus, an interference fringe image caused by a laser light source can be more sufficiently prevented.
As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used. In addition, the surface of the undercoat layer can be polished to adjust the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used. Note that in a photoconductor used in an image forming apparatus having a positively charged configuration, laser incident light is absorbed near the surface of the photoconductor and further scattered in the photoconductive layer. Not strongly required.

  It is also preferable to add various additives to the coating solution for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting substances such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, tita Umukireto compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β Examples include silane coupling agents such as-(aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. Is not limited to these There.

  Specific examples of the zirconium chelate compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate. , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Specific examples of the titanium chelate compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium. Examples thereof include salts, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Specific examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These additives can be used alone, but can also be used as a mixture or polycondensate of a plurality of compounds.

In addition, it is preferable that the above-described undercoat layer forming coating solution contains at least one electron accepting substance. Specific examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-di Examples include nitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are more preferably used. As a result, the photosensitivity layer can be improved in photosensitivity and the residual potential can be reduced, and the photosensitivity deterioration when repeatedly used can be reduced. The undercoat layer includes a photoconductor containing an electron accepting substance. The density unevenness of the toner image formed by the image forming apparatus can be sufficiently prevented.

  Moreover, it is also preferable to use the following dispersion-type undercoat layer coating agent instead of the above-described undercoat layer coating agent. Accordingly, accumulation of residual charges can be prevented by appropriately adjusting the resistance value of the undercoat layer, and the thickness of the undercoat layer can be increased. In particular, leakage during contact charging can be prevented.

Examples of the coating agent for the dispersion type undercoat layer include metal powders such as aluminum, copper, nickel, and silver, conductive metal oxides such as antimony oxide, indium oxide, tin oxide, and zinc oxide, carbon fiber, carbon Examples thereof include a conductive resin such as black or graphite powder dispersed in a binder resin. As the conductive metal oxide, metal oxide fine particles having an average primary particle size of 0.5 μm or less are preferably used. If the average primary particle size is too large, local conductive path formation is likely to occur, current leakage is likely to occur, and as a result, fogging or large current leakage from the charger may occur. The undercoat layer needs to be adjusted to an appropriate resistance value in order to improve leakage resistance. Therefore, the metal oxide fine particles described above preferably have a powder resistance of about 10 ² Ω · cm to 10 ¹¹ Ω · cm.

  In addition, if the resistance value of the metal oxide fine particles is lower than the lower limit of the above range, sufficient leakage resistance cannot be obtained, and if it is higher than the upper limit of the range, a residual potential may be increased. Therefore, among these, metal oxide fine particles such as tin oxide, titanium oxide, and zinc oxide having a resistance value within the above range are more preferably used. Moreover, 2 or more types of metal oxide fine particles can be mixed and used. Furthermore, the resistance of the powder can be controlled by subjecting the metal oxide fine particles to a surface treatment with a coupling agent. As the coupling agent that can be used at this time, the same material as the coating liquid for forming the undercoat layer described above can be used. Moreover, these coupling agents can also be used in mixture of 2 or more types.

For the surface treatment of the metal oxide fine particles, any known method can be used, but a dry method or a wet method can be used.
In the case of using the dry method, first, the metal oxide fine particles are dried by heating to remove surface adsorbed water. By removing the surface adsorbed water, the coupling agent can be uniformly adsorbed on the surface of the metal oxide fine particles. Next, while the metal oxide fine particles are stirred with a mixer having a large shearing force or the like, the coupling agent dissolved directly or in an organic solvent or water is dropped and sprayed together with dry air or nitrogen gas to be uniformly treated. . When adding or spraying the coupling agent, it is preferably performed at a temperature of 50 ° C. or higher. After adding or spraying the coupling agent, baking is preferably performed at 100 ° C. or higher. Due to the effect of baking, the coupling agent can be cured to cause a solid chemical reaction with the metal oxide fine particles. Baking can be carried out in an arbitrary range as long as the temperature and the time at which desired electrophotographic characteristics are obtained.

  In the case of using the wet method, first, the surface adsorbed water of the metal oxide fine particles is removed as in the dry method. As a method for removing the surface adsorbed water, in addition to the heat drying similar to the dry method, a method of removing with stirring and heating in a solvent used for the surface treatment, a method of removing by azeotropy with the solvent, and the like can be performed. Next, the metal oxide fine particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and a coupling agent solution is added and stirred or dispersed. Is done. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

It is essential that the amount of the surface treatment agent with respect to the metal oxide fine particles is an amount capable of obtaining desired electrophotographic characteristics. The electrophotographic characteristics are affected by the amount of the surface treatment agent attached to the metal oxide fine particles after the surface treatment. In the case of a silane coupling agent, the amount of adhesion is determined from the Si intensity (derived from the silane coupling agent) measured by fluorescent X-ray analysis and the main metal element strength of the metal oxide used. The Si intensity measured by this fluorescent X-ray analysis is preferably in the range of 1.0 × 10 ⁻⁵ times or more and 1.0 × 10 ⁻³ times or less of the main metal element strength of the metal oxide used. If it falls below this range, image quality defects such as fog are likely to occur, and if it exceeds this range, density reduction due to an increase in residual potential may easily occur.

Examples of the binder resin contained in the dispersion type undercoat layer coating agent include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, Known polymer resin compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, In addition, a charge transporting resin having a charge transporting group, a conductive resin such as polyaniline, and the like can be given.
Of these, resins insoluble in the coating solvent for the layer formed on the undercoat layer are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used. The ratio of the metal oxide fine particles to the binder resin in the dispersion type undercoat layer forming coating solution can be arbitrarily set within a range in which desired photoreceptor characteristics can be obtained.

Examples of the method for dispersing the metal oxide fine particles surface-treated by the above-described method in the binder resin include a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, and a roll mill. And a method using a medialess disperser such as a high-pressure homogenizer. Further, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which the fine liquid is penetrated and dispersed in a high pressure state.
The method of forming the undercoat layer with this dispersion-type undercoat layer coating agent can be carried out in the same manner as the method of forming the undercoat layer using the above-described undercoat layer coating agent.

-Photosensitive layer: Charge transport layer-
Next, the photosensitive layer will be described below in this order, divided into a charge transport layer and a charge generation layer.
Examples of the charge transport material used for the charge transport layer include those shown below. That is, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]- Pyrazoline derivatives such as 3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl) phenylamine, N, N-bis (3,4-dimethylphenyl) biphenyl Aromatic tertiary amino compounds such as -4-amine, dibenzylaniline, 9,9-dimethyl-N, N-di (p-tolyl) fluorenon-2-amine, N, N′-diphenyl-N, N Aromatic tertiary diamino compounds such as' -bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-diamine, 3- (4'-dimethylamino) 1,2,4-triazine derivatives such as phenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenyl Aminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, 1-pyrenediphenylhydrazone, 9-ethyl-3-[(2methyl-1-indolinylimino) methyl Carbazole, 4- (2-methyl-1-indolinyliminomethyl) triphenylamine, 9-methyl-3-carbazole diphenylhydrazone, 1,1-di- (4,4′-methoxyphenyl) acrylaldehyde diphenylhydrazone , Β, β-bis (methoxyphenyl) vinyldiphenyl Hydrazone derivatives such as drazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, p- (2,2-diphenyl) Hole transport materials such as α-stilbene derivatives such as vinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof are used. Or the polymer etc. which have the group which consists of the said compound in a principal chain or a side chain are mentioned. These charge transport materials can be used alone or in combination of two or more.

  Any binder resin can be used for the charge transport layer, but the binder resin is preferably compatible with the charge transport material and has an appropriate strength.

  Examples of this binder resin include various polycarbonate resins and copolymers thereof, such as bisphenol A, bisphenol Z, bisphenol C, and bisphenol TP, polyarylate resins and copolymers thereof, polyester resins, methacrylic resins, acrylic resins, Polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, silicone Resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-acrylic copolymer resin, ethylene-alkyd resin, poly-N-vinylcarbazole resin, polyvinyl butyral resin, polyphenylene ether resin, etc. And the like. These resins can be used alone or as a mixture of two or more.

  The molecular weight of the binder resin used for the charge transport layer is appropriately selected depending on the film thickness of the photosensitive layer and the film forming conditions such as the solvent, but is usually preferably within the range of 3000 to 300,000 in terms of viscosity average molecular weight. A range of 10,000 to 200,000 is more preferable.

  The charge transport layer can be formed by applying and drying a solution in which the charge transport material and the binder resin are dissolved in an appropriate solvent. Examples of the solvent used for forming the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, methylene chloride, chloroform and ethylene chloride. Halogenated aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof can be used. The blending ratio between the charge transport material and the binder resin is preferably in the range of 10: 1 to 1: 5. The thickness of the charge transport layer is generally preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 40 μm.

The charge transport layer and / or the charge generation layer, which will be described later, are used for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, light, or heat generated in the image forming apparatus. Additives such as stabilizers may be included.
Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones or their derivatives, organic sulfur compounds, and organic phosphorus compounds.

  As specific examples of antioxidants, phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′- Di-t-butyl-4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t- Butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4'-thio- Bis- (3-methyl-6-tert-butylphenol), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene- -(3 ', 5'-di-t-butyl-4'-hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5- Methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 3-3 ′, 5′-di-t-butyl-4′- And hydroxyphenyl) stearyl propionate.

  Among hindered amine compounds, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2 , 2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Condensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetramethyl- 4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2- n-Butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N— (1,2,2,6,6, -pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

Organic sulfur-based antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis- (Β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.
Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfeft, tris (2,4-di-t-butylphenyl) -phosfte, and the like.

  Organic sulfur and organophosphorus antioxidants are called secondary antioxidants, and when used in combination with primary antioxidants such as phenols or amines, the antioxidant effect is increased synergistically. Can do.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-di-hydroxy-4-methoxybenzophenone.
As the benzotriazole light stabilizer, 2-(-2′-hydroxy-5′methylphenyl-)-benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″) , 6 ″ -tetra-hydrophthalimido-methyl) -5′-methylphenyl] -benzotriazole, 2-(-2′-hydroxy-3′-t-butyl 5′-methylphenyl-)-5-chlorobenzo Triazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl-)-5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl- ) -Benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl-)-benzotriazole Etc.
Other light stabilizers include 2,4, di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like.

The charge transport layer can be formed by applying a solution obtained by dissolving the charge transport material and the binder resin described above in an appropriate solvent and drying the solution. Examples of the solvent used for preparing the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, and halogens such as methylene chloride, chloroform and ethylene chloride. Cyclic aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof can be used.
In addition, a small amount of silicone oil can be added to the charge transport layer forming coating solution as a leveling agent for improving the smoothness of the coating film to be formed.

  The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5 by mass ratio. In general, the thickness of the charge transport layer is preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 30 μm.

  The coating solution for forming the charge transport layer can be applied by dip coating, ring coating, spray coating, bead coating, blade coating, roller coating, knife coating, curtain coating, depending on the shape and application of the photoreceptor. It can be performed using a coating method such as a coating method. The drying is preferably performed by heating after touch-and-drying at room temperature. The heat drying is desirably performed in a temperature range of 30 ° C. or higher and 200 ° C. or lower for a time in the range of 5 minutes to 2 hours.

-Photosensitive layer: Charge generation layer-
The charge generation layer is formed by depositing a charge generation material by a vacuum deposition method or by applying a solution containing an organic solvent and a binder resin.

Examples of charge generation materials include amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, and other selenium compounds; inorganic photoconductors such as selenium alloy, zinc oxide, and titanium oxide; Sensitized, various phthalocyanine compounds such as metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, tin phthalocyanine, gallium phthalocyanine; Various organic pigments such as salts; or dyes are used.
In addition, these organic pigments generally have several types of crystals. In particular, phthalocyanine compounds have various crystal types including α type and β type. Any of these crystal forms can be used as long as it is a pigment capable of obtaining characteristics.

  Of the charge generation materials described above, phthalocyanine compounds are preferred. In this case, when the photosensitive layer is irradiated with light, the phthalocyanine compound contained in the photosensitive layer absorbs photons and generates carriers. At this time, since the phthalocyanine compound has a high quantum efficiency, the absorbed photons can be efficiently absorbed to generate carriers.

Furthermore, among the phthalocyanine compounds, phthalocyanines as shown in the following (1) to (3) are more preferable. That is,
(1) At least 7.6 °, 10.0 °, 25.2 °, 28.0 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material Crystalline hydroxygallium phthalocyanine having a diffraction peak at the position.
(2) At least 7.3 °, 16.5 °, 25.4 °, 28.1 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material Crystalline chlorogallium phthalocyanine having a diffraction peak at the position.
(3) Diffraction peaks at positions of at least 9.5 °, 24.2 °, and 27.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material. A crystalline form of titanyl phthalocyanine.

  Since these phthalocyanine compounds have not only high photosensitivity but also high stability of photosensitivity, a photoreceptor having a photosensitive layer containing these phthalocyanine compounds is required to have high-speed image formation and reproducibility. It is suitable as a photoreceptor for a color image forming apparatus.

  Note that the peak intensity and position may slightly deviate from these values depending on the crystal shape and measurement method. However, if the X-ray diffraction patterns are basically the same, the same crystal type is assumed. I can judge.

  Examples of the binder resin used for the charge generation layer include the following. That is, polycarbonate resin such as bisphenol A type or bisphenol Z type and copolymers thereof, polyarylate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin Vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like.

  These binder resins can be used alone or in admixture of two or more. The mixing ratio of the charge generation material and the binder resin (charge generation material: binder resin) is preferably in the range of 10: 1 to 1:10 by mass ratio. The thickness of the charge generation layer is generally preferably in the range of 0.01 μm to 5 μm, and more preferably in the range of 0.05 μm to 2.0 μm.

The charge generation layer may contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like. Examples of the electron accepting material used in the charge generation layer include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, and o-dinitrobenzene. M-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, peak phosphoric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable.

As a method for dispersing the charge generating material in the resin, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, and a colloid mill can be used.
Known organic solvents as coating solution solvents for forming the charge generation layer, for example, aromatic hydrocarbon solvents such as toluene and chlorobenzene, fats such as methanol, ethanol, n-propanol, iso-propanol, and n-butanol Aromatic alcohol solvents, ketone solvents such as acetone, cyclohexanone and 2-butanone, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or straight chain such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether And ether solvents such as methyl ether, methyl acetate, ethyl acetate, and n-butyl acetate.

  These solvents can be used alone or in combination of two or more. When two or more kinds of solvents are mixed and used, any solvent that can dissolve the binder resin as the mixed solvent can be used. However, when the photosensitive layer has a layer structure in which the charge transport layer and the charge generation layer are formed in this order from the conductive substrate side, charge generation is performed using a coating method that easily dissolves the lower layer, such as dip coating. When forming the layer, it is desirable to use a solvent that does not dissolve the lower layer such as the charge transport layer. In addition, when the charge generation layer is formed by using a spray coating method or a ring coating method having a relatively low erosion property of the lower layer, the selection range of the solvent can be expanded.

<Process cartridge and image forming apparatus>
Next, a process cartridge and an image forming apparatus using the photoreceptor of the present invention will be described.
The process cartridge of the present invention is not particularly limited as long as it uses the photoconductor of the present invention, and specifically, at least one selected from the photoconductor of the present invention, a charging unit, a developing unit, and a cleaning unit. It is preferable to have a structure that can be attached to and detached from the main body of the image forming apparatus.

  Further, the image forming apparatus of the present invention is not particularly limited as long as it uses the photoreceptor of the present invention. Specifically, the photoreceptor of the present invention, a charging unit for charging the surface of the photoreceptor, An exposure unit (electrostatic latent image forming unit) that forms an electrostatic latent image by exposing the surface of the photoreceptor charged by the charging unit, and a toner image is formed by developing the electrostatic latent image with a developer containing toner. And a transfer means for transferring the toner image to a recording medium. The image forming apparatus of the present invention may be a so-called tandem machine having a plurality of photoconductors corresponding to the toners of the respective colors. In this case, it is preferable that all the photoconductors are the photoconductors of the present invention. The toner image may be transferred by an intermediate transfer system using an intermediate transfer member.

  FIG. 5 is a schematic configuration diagram showing a basic configuration of a preferred embodiment of the process cartridge of the present invention. The process cartridge 100 is mounted with a charging unit 108, a developing unit 111, a cleaning unit 113, an opening 105 for exposure, and a static eliminator 114 together with the electrophotographic photosensitive member 107, and is combined using a case 101 and a mounting rail 103. It is an integrated one. The process cartridge 100 is detachably attached to an image forming apparatus main body including a transfer unit 112, a fixing device 115, and other components not shown, and the image forming apparatus together with the electrophotographic apparatus main body. It constitutes.

  FIG. 6 is a schematic configuration diagram of a basic configuration of an embodiment of the image forming apparatus of the present invention. The image forming apparatus 200 shown in FIG. 6 is charged by an electrophotographic photosensitive member 207, a charging unit 208 that charges the electrophotographic photosensitive member 207 by a contact method, a power source 209 connected to the charging unit 208, and a charging unit 208. An exposure unit 210 that exposes the electrophotographic photosensitive member 207, a developing unit 211 that develops a portion exposed by the exposure unit 214, and a transfer unit 212 that transfers an image developed on the electrophotographic photosensitive member 7 by the developing unit 211. A cleaning device 213, a static eliminator 214, and a fixing device 215.

  The process cartridge of the present invention and the cleaning means for the photoreceptor of the image forming apparatus are not particularly limited, but a cleaning blade is preferable. The cleaning blade is likely to damage the surface of the photosensitive member and promote wear compared to other cleaning means. However, since the process cartridge and the image forming apparatus of the present invention use the photoconductor of the present invention as the photoconductor, it is possible to suppress the occurrence of scratches and wear on the surface of the photoconductor even during long-term use. it can.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
<Example 1>
(Preparation of electrophotographic photoreceptor)
First, an organic photoreceptor was produced by laminating an undercoat layer, a charge generation layer, and a charge transport layer in this order on an Al substrate by the procedure described below.

-Formation of undercoat layer-
20 parts by mass of a zirconium compound (trade name: Organotix ZC540 manufactured by Matsumoto Pharmaceutical Co., Ltd.), 2.5 parts by mass of a silane compound (trade name: A1100 manufactured by Nippon Unicar Co., Ltd.), a polyvinyl butyral resin (trade name: S-REC BM- manufactured by Sekisui Chemical Co., Ltd.) S) A solution obtained by stirring and mixing 10 parts by mass and 45 parts by weight of butanol was applied to the surface of an Al substrate having an outer diameter of 84 mm, and dried by heating at 150 ° C. for 10 minutes, thereby subtracting a film thickness of 1.0 μm. A layer was formed.

-Formation of charge generation layer-
Next, a mixture obtained by mixing 1 part by mass of chlorogallium phthalocyanine as a charge generation material with 1 part by mass of polyvinyl butyral (trade name: S-REC BM-S manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by mass of n-butyl acetate. Dispersion with a glass bead with a paint shaker for 1 hour gave a dispersion for forming a charge generation layer.
This dispersion was applied on the undercoat layer by an immersion method and then dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

-Formation of charge transport layer-
Next, 2 parts by mass of a compound represented by the following structural formula (1) and 3 parts by mass of a polymer compound (viscosity average molecular weight: 39000) represented by the following structural formula (2) are used as chlorobenzene 20 A charge transport layer forming coating solution was obtained by dissolving in mass parts.

  This coating solution is applied onto the charge generation layer by an immersion method, heated at 110 ° C. for 40 minutes to form a 20 μm-thick charge transport layer, and the undercoat layer, the charge generation layer, and the charge transport layer are formed on the Al substrate. An organic photoreceptor (hereinafter, sometimes referred to as “non-coated photoreceptor”) in which the layers were laminated in this order was obtained.

-Formation of intermediate layer-
The formation of the intermediate layer on the surface of the non-coated photoreceptor was performed using a film forming apparatus having the configuration shown in FIG.
First, the non-coated photoreceptor was placed on the substrate holder 13 in the film forming chamber 10 of the film forming apparatus, and the film forming chamber 10 was evacuated through the exhaust port 11 until the pressure reached about 0.1 Pa. Next, a gas in which nitrogen gas and hydrogen gas are mixed at a ratio of 1: 2 is supplied into a high-frequency discharge tube portion 21 provided with an electrode 19 having a diameter of 50 mm from the gas introduction tube 20 (nitrogen gas 100 sccm, hydrogen gas). 200 sccm) was introduced, and a radio wave of 13.56 MHz was set at an output of 100 W by the high-frequency power supply unit 18 and a matching circuit (not shown in FIG. 4), and matching was performed with a tuner to discharge from the electrode 19. The reflected wave at this time was 0 W.
Next, a mixed gas containing trimethylgallium gas using hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. is supplied from the shower nozzle 16 to the plasma diffusion portion 17 in the film formation chamber 10 through the gas introduction portion 3 at 3 sccm. Introduced. At this time, the reaction pressure in the film forming chamber 10 measured with a Baratron vacuum gauge was 40 Pa.

  In this state, the non-coated photoreceptor was rotated for 60 minutes while rotating at a speed of 10 rpm to form a GaN film having a thickness of 0.15 μm, and an organic photoreceptor having an intermediate layer provided on the surface of the charge transport layer was obtained. .

Moreover, when the infrared absorption spectrum measurement of the sample film | membrane formed into a film | membrane on Si substrate on the conditions similar to the above was implemented, the peak resulting from a Ga-H bond, a Ga-N bond, and a N-H bond was confirmed. From these facts, it was found that the intermediate layer contained gallium, nitrogen, hydrogen and oxygen. The intensity ratio of the absorption peak due to the N—H bond and the Ga—H bond to the Ga—N bond was 0.05 and 0.1, respectively, and the FWHM of the GaN absorption peak was 200 cm ^−1. It was.

-Formation of surface layer-
Following the formation of the intermediate layer, a gas obtained by mixing nitrogen gas, helium gas, hydrogen gas, and oxygen gas is supplied from the gas introduction tube 20 into the high-frequency discharge tube portion 21 provided with the electrode 19 having a diameter of about 100 sccm ( Nitrogen gas 100 sccm, helium gas 150 sccm, hydrogen 200 sccm, oxygen 0.3 sccm) are introduced, and a radio wave of 13.56 MHz is set to an output of 100 W by a high frequency power supply unit 18 and a matching circuit (not shown in FIG. 1). Matching was performed and discharging was performed from the electrode 19. The reflected wave at this time was 0 W.
Next, a mixed gas containing trimethylgallium gas using hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. is supplied from the shower nozzle 16 to the plasma diffusion portion 17 in the film formation chamber 10 through the gas introduction portion 3 at 3 sccm. Introduced. At this time, the reaction pressure in the film forming chamber 10 measured with a Baratron vacuum gauge was 40 Pa.

  In this state, a non-coated photoreceptor having an intermediate layer formed thereon is rotated for 60 minutes while rotating at a speed of 1 rpm, and a photoreceptor (on which a GaON film containing 0.25 μm of hydrogen is formed as a surface layer on the intermediate layer) 1) was obtained. In the film formation, the non-coated photoconductor was not heat-treated. In addition, in order to monitor the temperature at the time of film formation, the color of the thermotape previously attached to the surface of the non-coated photoreceptor before film formation was confirmed after film formation, and was 45 ° C.

-Analysis and evaluation of surface layer and intermediate layer-
When forming the surface layer, a sample film was formed on the intermediate layer using the Si substrate on which the intermediate layer was formed at the same time. About this sample film | membrane, the composition of the film | membrane was measured using Rutherford back scattering (RBS) and hydrogen forward scattering (HFS). As a result, it is found that gallium, nitrogen, and hydrogen are 38 atomic percent, 40 atomic percent, and 22 atomic percent for the intermediate layer, respectively, and gallium, nitrogen, oxygen, and hydrogen are each 35 atomic percent for the surface layer. 18 atomic%, 30 atomic%, and 17 atomic%. Oxygen was distributed throughout the surface layer, and the carbon contained in the surface layer was below the detection limit (0.5 atomic%). In addition, in the diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement A blurred ring was seen in the halo pattern, and the formed film was found to be an amorphous microcrystalline film.

-Surface characteristics-
·hardness
Hardness is the occurrence of scratches on the film surface when the corner of the Si crystal having a size of 5 × 10 mm is lightly pressed and rubbed against a sample film of about 10 × 10 mm formed on the Si crystal substrate used in the composition analysis. The condition was visually evaluated according to the following criteria.
A: No scratches are generated.
◯: When the observation angle of the film surface after rubbing is changed, a scratched after rubbing is observed, but there is no practical problem.
X: Scratches that can be easily confirmed visually are observed on the film surface.

-Slip The sensory evaluation of the slip when the surface of the photoconductor before the print test was rubbed with a clean tissue (Bencot). The evaluation criteria are as follows.
(Double-circle): There is no feeling which sticks between a bencott and a photoreceptor surface, and a slide is very good.
○: There may be a slight squeezing between the bencott and the surface of the photoreceptor, but basically the sliding is good.
X: There is a feeling of being caught between the bend and the surface of the photoreceptor, and the bend may be broken in some cases.

・ Initial water resistance
Initial water resistance was evaluated by immersing a sample film formed on a Si substrate immediately after film formation in pure water for 10 seconds and then pulling it up and observing the surface state of the film with the naked eye. The evaluation criteria are as follows.
A: No change is observed on the film surface before and after immersion in pure water.
○: A slight change may be seen on the surface of the film before and after immersion in pure water, but it is difficult to distinguish from scale.
X: The surface of the film is seen before and after being immersed in pure water, and the surface after immersing the surface of the film after immersion is seen.

・ Initial contact angle
The initial contact angle is purely applied to a sample film formed on a Si substrate immediately after film formation in a 23 ° C./55% RH environment using a contact angle measuring device CA-X roll type (manufactured by Kyowa Interface Science Co., Ltd.). It was measured by dropping water. In addition, the average value at the time of repeating the measurement three times at different locations was determined as the contact angle.

(Evaluation)
Next, the electrophotographic characteristics of the organic photoreceptor provided with the intermediate layer and the surface layer were evaluated. First, exposure light (light source: semiconductor laser, wavelength 780 nm, output 5 mW) is used for the above-described non-coated photoconductor before formation of the surface layer and the photoconductor provided with the surface layer. The residual potential of the surface after irradiation was measured in a state where the surface was negatively charged to −700 V by a scorotron charger while rotating at 40 rpm while scanning the surface. As a result, it was found that the non-coated photoreceptor is -20V, while the organic photoreceptor provided with the surface layer is -60V or less and has a good temperature and humidity dependency and a good level.
In addition, for the influence on the sensitivity, the wavelength of the light source was evaluated from the infrared region to the entire visible region, but there was almost no difference between the non-coated photoreceptor and the photoreceptor provided with the surface layer, and the surface layer was provided. It was found that there was no decrease in sensitivity due to the above.
Further, a peel test was performed on the surface of the photoreceptor provided with the surface layer to peel off the attached adhesive tape. The surface layer did not peel at all, and it was found that the adhesion was good.

  Next, the photoconductor provided with the intermediate layer and the surface layer is attached to the DocuCenter Color 500 manufactured by Fuji Xerox Co., Ltd., and a continuous 20000 print test is performed under a high temperature and high humidity environment (28 ° C., 80% RH). The following evaluation was performed. As a reference for image quality evaluation, a non-coated photoconductor was also attached to the DocuCenter Col0r 500 to form a similar image.

-White stripe-
The white streak defect on the image was evaluated for the images before and after the completion of printing 20,000 sheets. The evaluation criteria are as follows.
○: White streak-like image defects are hardly seen.
X: Many white streak-like image defects that are thought to be caused by scratches on the photoreceptor are observed.

-Image density-
After printing 1000 sheets, 100 solid images with an area coverage of 100% were printed continuously, and when it was confirmed that the image density was lowered at first glance, the density was lowered.

-Image blur-
The image blur was wiped off only a part of the surface of the photoreceptor to remove the water-soluble discharge product after the 20,000-sheet print test.
Thereafter, a halftone image (image density of 30%) is printed, and whether or not a density difference corresponding to a location where the surface of the photoreceptor is wiped and a location where the surface is not wiped can be visually confirmed in the halftone image. When the density difference can be easily confirmed at a glance, it is determined that the image blur has occurred.

-Scratch-
The surface of the photoreceptor after the print test was visually observed to check for the presence of scratches on the surface.
The above results are summarized in Table 1.

<Example 2>
In the production of the electrophotographic photosensitive member of Example 1, the surface layer was formed by introducing an amount of gas mixed with nitrogen gas, helium gas, hydrogen gas and oxygen gas from the gas introduction pipe 20 to about 450 sccm (nitrogen gas). A photoconductor (2) was obtained in the same manner as in Example 1 except that the gas was changed to 100 sccm, helium gas 150 sccm, hydrogen 200 sccm, oxygen 0.6 sccm).

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (2) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 3>
In the production of the electrophotographic photosensitive member of Example 1, first, an intermediate layer is formed by mixing a gas obtained by mixing nitrogen gas, helium gas, hydrogen gas, and oxygen gas into the high-frequency discharge tube portion 21 from the gas introduction tube 20. About 450 sccm (nitrogen gas 100 sccm, helium gas 150 sccm, hydrogen gas 200 sccm, oxygen gas 0.02 sccm) was introduced, and a mixed gas containing trimethylgallium gas containing hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. An intermediate layer was formed in the same manner as in Example 1 except that 3 sccm was introduced into the plasma diffusion portion 17 in the substrate 10.

  Next, the surface layer is formed by introducing an amount of gas mixed with nitrogen gas, helium gas, hydrogen gas and oxygen gas from the gas introduction pipe 20 to about 450 sccm (nitrogen gas 100 sccm, helium gas 150 sccm, hydrogen 200 sccm, oxygen 0.8 sccm) except that 4 sccm of a mixed gas containing trimethylgallium gas using hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. is introduced into the plasma diffusion portion 17 in the film forming chamber 10. A surface layer was formed in the same manner as in Example 1 to obtain a photoreceptor (3).

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (3) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 4>
In the production of the electrophotographic photosensitive member of Example 1, first, an intermediate layer is formed by mixing a gas obtained by mixing nitrogen gas, helium gas, hydrogen gas, and oxygen gas into the high-frequency discharge tube portion 21 from the gas introduction tube 20. About 450 sccm (nitrogen gas 100 sccm, helium gas 150 sccm, hydrogen gas 200 sccm, oxygen gas 0.03 sccm) is introduced, and a mixed gas containing trimethylgallium gas containing hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. An intermediate layer was formed in the same manner as in Example 1 except that 3 sccm was introduced into the plasma diffusion portion 17 in the substrate 10.

  Next, the surface layer is formed by introducing an amount of gas mixed with nitrogen gas, helium gas, hydrogen gas and oxygen gas from the gas introduction pipe 20 to about 450 sccm (nitrogen gas 100 sccm, helium gas 150 sccm, hydrogen 200 sccm, oxygen 1.0 sccm) except that 4 sccm of a mixed gas containing trimethylgallium gas using hydrogen gas as a carrier gas and maintained at a pressure of 101 kPa at 0 ° C. is introduced into the plasma diffusion part 17 in the film forming chamber 10. A surface layer was formed in the same manner as in Example 1 to obtain a photoreceptor (4).

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (4) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 5>
In the production of the electrophotographic photosensitive member of Example 3, the intermediate layer was formed by introducing a gas mixed with hydrogen gas, helium gas, and oxygen gas from the gas introduction pipe 20 to about 400 sccm (hydrogen 200 sccm, helium 200 The intermediate layer was formed in the same manner as in Example 1 except that the oxygen was changed to 0.02 sccm. Further, the surface layer is formed except that the amount of gas mixed from hydrogen gas, helium gas and oxygen gas introduced from the gas introduction pipe 20 is changed to about 400 sccm (hydrogen 200 sccm, helium 200, oxygen 0.8 sccm). In the same manner as in Example 1, a photoreceptor (5) was obtained.

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (5) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 6>
In the production of the electrophotographic photoreceptor of Example 3, the surface layer was formed by changing the amount of gas mixed with hydrogen gas and nitrogen gas from the gas introduction pipe 20 to about 350 sccm (hydrogen 200 sccm, nitrogen 150 sccm). A photoconductor (6) was obtained in the same manner as in Example 1 except that.

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (6) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 7>
In the production of the electrophotographic photoreceptor of Example 1, first, the intermediate layer was formed so that the flow rate of the trimethylgallium mixed gas was 5 sccm, and the intermediate layer was formed in the same manner as in Example 1. At this time, the film thickness was 0.5 μm.

  Next, the formation of the surface layer was introduced so that the flow rate of the trimethylgallium mixed gas was 4 sccm, and the surface layer was formed in the same manner as in Example 1 to obtain a photoreceptor (7). The surface layer was 1.8 μm, and the thickness of the surface layer and the intermediate layer was 2.3 μm.

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (7) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 8>
In the production of the electrophotographic photosensitive member of Example 5, first, the intermediate layer was formed in the same manner as in Introduction Example 5 so that the flow rate of the trimethylgallium mixed gas was 3 sccm. However, the film thickness was 0.05 μm.

  Next, the formation of the surface layer was introduced so that the flow rate of the trimethylgallium mixed gas was 3 sccm, and the surface layer was formed in the same manner as in Example 5 except that the oxygen flow rate was different from 0.2 sccm. Obtained. The surface layer was 0.4 μm.

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (8) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Example 9>
In the production of the electrophotographic photoreceptor of Example 5, first, the intermediate layer was formed so that the flow rate of the trimethylgallium mixed gas was 3 sccm, and the intermediate layer was formed in the same manner as in Example 5. However, the film thickness was 0.35 μm.

  Next, the formation of the surface layer was introduced so that the flow rate of the trimethylgallium mixed gas was 3 sccm, and the surface layer was formed in the same manner as in Example 5 to obtain a photoreceptor (9). The surface layer was 0.05 μm.

In the evaluation of Example 1, the evaluation was performed in the same manner except that the photoconductor (9) was used instead of the photoconductor (1).
The results are shown in Table 1 including analysis of the surface layer and the like.

<Comparative Example 1>
In Example 1, the flow rates and ratios of the gas containing trimethylgallium (TMG), nitrogen gas, helium gas, hydrogen gas, and oxygen gas are changed so that the entire film thickness is the same without forming the intermediate layer. Except for the above, film formation was performed in the same manner as in Example 1 to prepare a photoreceptor (10) having a surface layer formed thereon.
Evaluation was performed in the same manner as in Example 1 using the photoreceptor (10). The results are shown in Table 1.

<Comparative example 2>
In Example 4, the flow rates and ratios of the gas containing trimethylgallium (TMG), nitrogen gas, helium gas, hydrogen gas, and oxygen gas are changed so that the entire film thickness is the same without forming the intermediate layer. Except for the above, film formation was performed in the same manner as in Example 1 to prepare a photoconductor (11) having a surface layer formed thereon.
Evaluation was performed in the same manner as in Example 1 using the photoreceptor (11). The results are shown in Table 1.

  As shown in Table 1, in the photoconductor of the example provided with the intermediate layer, the image density does not decrease even in the repeated print output under the high temperature and high humidity environment as compared with the photoconductor without the intermediate layer of the comparative example. I understood it.

FIG. 2 is a schematic cross-sectional view illustrating an example of a layer configuration of a photoreceptor of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor of the present invention. 1 is a schematic diagram illustrating an example of a film forming apparatus used for forming an intermediate layer and a surface layer of a photoconductor of the present invention. It is a schematic diagram which shows an example of the plasma generator which can be used for this invention. It is a schematic block diagram which shows an example of the process cartridge of this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive substrate, 2,6 Photosensitive layer, 2A Charge generation layer, 2B Charge transport layer, 3 Surface layer, 4 Undercoat layer, 5 Intermediate layer, 10 Film-forming chamber, 11 Exhaust port, 12 Base rotation part, 13 Base Holder, 14 Base material, 15 Gas introduction part, 16 Shower nozzle, 17 Plasma diffusion part, 18 High frequency power supply part, 19 Flat plate electrode, 20 Gas introduction pipe, 21 High frequency discharge pipe part, 22 High frequency coil, 23 Quartz tube, 101 Case, 103 mounting rail, 105 opening, 107, 207 electrophotographic photosensitive member, 108, 208 charging means, 111, 211 developing means, 112, 212 transfer means, 113, 213 cleaning device, 114, 214 static eliminator, 115, 215 Fixing device, 210 exposure means

Claims (6)

It is configured by laminating a photosensitive layer, an intermediate layer, and a surface layer in this order on a conductive substrate,
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the types and composition ratios of the contained elements in the intermediate layer and the surface layer is different. An electrophotographic photosensitive member characterized by the above.   2. The layer thickness of the surface layer and the intermediate layer is 0.1 μm or more and less than 5 μm, and is in the range of 0.5 to 10% with respect to the layer thickness of the photosensitive layer. The electrophotographic photoreceptor described in 1.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer contains hydrogen.   The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains an organic material. An electrophotographic photoreceptor constituted by laminating a photosensitive layer, an intermediate layer and a surface layer in this order on a conductive substrate, and at least one selected from a charging means, a developing means and a cleaning means, and
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the type and composition ratio of the contained elements in the intermediate layer and the surface layer is different. A process cartridge characterized by that. An electrophotographic photosensitive member constituted by laminating a photosensitive layer, an intermediate layer and a surface layer in this order on a conductive substrate, a charging means for charging the surface of the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member Electrostatic latent image forming means for forming an electrostatic latent image on the surface, developing means for developing the electrostatic latent image as a toner image with a developer containing toner, transfer means for transferring the toner image to a recording medium, Comprising at least
Each of the intermediate layer and the surface layer contains a group 13 element and at least one of oxygen and nitrogen, and at least one of the type and composition ratio of the contained elements in the intermediate layer and the surface layer is different. An image forming apparatus.

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