JP4600111B2 - Electrophotographic photosensitive member, process cartridge and image forming apparatus using the same - Google Patents

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 photosensitive member is required to have a longer lifetime. In order to extend the life of the electrophotographic photosensitive member, it is necessary to improve the wear resistance. Therefore, it is required to increase the hardness of the surface of the photosensitive member.
However, in the photoreceptor whose surface is made of amorphous silicon having a high hardness, adhesion of discharge products and the like are likely 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 for forming an amorphous silicon carbide surface protective layer on a photosensitive organic layer using a catalytic CVD method (see Patent Document 1), and a trace amount in amorphous carbon for the purpose of improving moisture resistance and printing durability. Technology (see Patent Literature 2), technology using diamond-bonded amorphous carbon nitride (see Patent Literature 3), technology using non-single-crystal hydrogenated nitride semiconductor (see Patent Literature 4) Proposed.

  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 Patent Document 5). However, since magnesium fluoride dissolves in water and acid, the moisture resistance in a high humidity atmosphere 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 is a problem.
JP 2003-316053 A Japanese Patent Laid-Open No. 2-110470 JP 2003-27238 A Japanese Patent Laid-Open No. 11-186571 JP 2003-29437 A

As described above, the surface layer of the photoreceptor can achieve both high hardness and excellent transparency, and can suppress image defects caused by adhesion of discharge products. However, it is difficult to make all these properties compatible at a high level with the conventionally known materials as described above.
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.

<1>
In an electrophotographic photoreceptor including a conductive substrate, a photosensitive layer, and a surface layer, and the photosensitive layer and the surface layer are laminated in this order on the conductive substrate.
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 by performing XPS measurement by irradiating the outermost surface with 10 kV, 20 mA using MgKα rays as an X-ray source. An electrophotographic photosensitive member characterized by containing at least atomic% .

<2>
The electrophotographic photosensitive member according to <1>, wherein a concentration distribution of oxygen contained in the surface layer in the thickness direction of the surface layer decreases toward the photosensitive layer side.

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

<4>
The electrophotographic photosensitive member according to <1>, wherein the surface layer is amorphous.

<5>
The electrophotographic photosensitive member according to <1>, wherein the surface layer contains hydrogen.

<6>
The electrophotographic photosensitive member according to <1>, wherein the photosensitive layer contains silicon atoms.

<7>
The electrophotographic photosensitive member according to <1>, wherein the photosensitive layer includes an organic photosensitive material.

<8>
An electrophotographic photosensitive member comprising a conductive substrate, a photosensitive layer, and a surface layer, wherein the photosensitive layer and the surface layer are laminated in this order on the conductive substrate; a charging unit; a developing unit; a cleaning unit; In the process cartridge which integrally has at least one selected from the group consisting of static elimination means and is detachable from the image forming apparatus main body,
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 by performing XPS measurement by irradiating the outermost surface with 10 kV, 20 mA using MgKα rays as an X-ray source. A process cartridge characterized by at least atomic percent .

<9>
An electrophotographic photoreceptor comprising a conductive substrate, a photosensitive layer, and a surface layer, wherein the photosensitive layer and the surface layer are laminated in this order on the conductive substrate, and charging the surface of the electrophotographic photoreceptor A charging means; an exposure means for exposing the surface of the electrophotographic photosensitive member charged by the charging means to form an electrostatic latent image; and developing the electrostatic latent image with a developer containing toner to form a toner image. In an image forming apparatus comprising: a developing unit that forms; and a transfer unit that transfers the toner image to a recording medium.
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 atoms by XPS measurement by irradiating the outermost surface X-ray source with MgKα ray at 10 kV and 20 mA. % Or more of the image forming apparatus.

  As described above, according to the present invention, the surface is excellent in mechanical durability and oxidation resistance, can suppress image defects caused by adhesion of discharge products, and has excellent sensitivity. It is possible to provide an electrophotographic photosensitive member that can be easily maintained at a high level over time, and a process cartridge and an image forming apparatus using the same.

(Electrophotographic photoreceptor)
Electronic photosensitive member (hereinafter sometimes referred to as "photosensitive member") has a conductive substrate, a photosensitive layer, and a surface layer, and the photosensitive layer and the surface layer on the conductive substrate In the electrophotographic photoreceptor laminated in this order, at least the outermost surface of the surface layer contains oxygen and a group 13 element, and the content of the oxygen in the outermost surface exceeds 15 atomic%. .

“At least the outermost surface layer” means an extremely thin layer having a depth of at least several nanometers from the surface (specifically, a range of about 1 to 50 nm from the surface). Means a layer corresponding to the measurement range in the depth direction when the solid surface is measured by XPS (X-ray photoelectron spectroscopy). Note that the layer containing the group 13 element, oxygen, and the main constituent element preferably has a thickness of 0.5 nm or more in the depth direction from the surface of the surface layer, and preferably has a thickness of 10 nm or more. Is more preferable.
At least the outermost surface of the surface layer is the most important part for preventing the photoconductor from being worn and preventing scratches. In addition, the two elements contained in the outermost surface constitute an oxide of a group 13 element excellent in hardness and transparency. Therefore, the photoreceptor of the present invention is excellent in surface abrasion resistance, suppresses generation of scratches, and easily obtains good sensitivity. Further, since the outermost surface contains an oxide of a group 13 element, the surface of the photoconductor itself is difficult to be oxidized in an oxidizing atmosphere generated by a charger, such as ozone or nitrogen oxide, in the image forming apparatus. It is possible to prevent deterioration of the photoconductor due to the above. In addition, since the adhesion of the discharge product on the outermost surface can be suppressed, the occurrence of image defects can also be suppressed. Moreover, since it is excellent in mechanical durability as mentioned above, it is easy to maintain these characteristics at a high level over a long period of time. In addition, it is more preferable that the outermost surface is composed of an oxide of a group 13 element.

Sensitive light body, the entire surface layer, oxygen may be made of 13 group element and only, but other elements of nitrogen and hydrogen, etc. besides this be included, as required for the surface layer It may be. By using such a third element, the composition, structure, and various physical properties of the surface layer can be controlled more easily and flexibly, so that the above-described effects can be easily achieved at a higher level.
In particular, as the third element, the surface layer preferably contains nitrogen. In this case, the bond between the group 13 element and nitrogen can provide high hardness and transparency, and sufficient mechanical durability can be obtained. Furthermore, as will be described later, it is also preferable that the surface layer contains hydrogen from the viewpoint that structural defects in the surface layer can be suppressed.

Further, the composition in the thickness direction of the surface layer may have an inclined structure or may be composed of two or more multilayer structures.
Further, the oxygen concentration distribution in the thickness direction of the surface layer may be uniform or non-uniform, but preferably decreases toward the photosensitive layer side (that is, increases toward the surface side of the photoreceptor). Further, in the vicinity of the surface side of the photoreceptor, it is composed of oxygen and a group 13 element, and in the vicinity of the photoreceptor layer side of the photoreceptor, it is composed of elements other than oxygen and a group 13 element (that is, does not include oxygen). Is preferred.
By having such an oxygen concentration distribution, it is possible to achieve a higher level of both mechanical durability, oxidation resistance, image defects and sensitivity due to adhesion of discharge products, and to improve these characteristics. It is easy to maintain for a long period of time, and this effect is further exhibited particularly when the other element than oxygen is nitrogen. In addition, the distribution profile of the oxygen concentration in the surface layer thickness direction is not particularly limited, and may be, for example, linear, curved, or stepped.

  In addition, when nitrogen is contained in the surface layer, the content is preferably 60 atomic percent or less, and more preferably 50 atomic percent or less. When the nitrogen content exceeds 60 atomic%, the water resistance of the surface layer becomes insufficient, so that it may lack practicality. Further, the nitrogen concentration distribution in the surface layer thickness direction may be uniform or non-uniform, but is preferably not substantially contained in the outermost surface.

As the group 13 element contained in the surface layer, specifically, at least one element selected from B, Al, Ga, and In can be used. The content of these atoms in the surface layer needs to be selected so as not to absorb as much light as possible used for exposure of the surface of the photoreceptor, but generally it is preferably within the following range.
That is, the content of these atoms in the surface layer when using B, Al and Ga atoms is preferably in the range of 0.1 atomic% to 50 atomic%, and in the range of 5 atomic% to 40 atomic%. More preferably, it is within. When the content of B, Al, or Ga atoms is less than 0.1 atomic%, it may be difficult to form the surface layer itself. On the other hand, if the content exceeds 50 atomic%, the transparency of the surface layer is lowered, the amount of light incident on the photosensitive layer is reduced, and the sensitivity of the photoreceptor may be lowered.
The content in the case of using In atoms as the group 13 element is preferably 0.1 atomic% to 50 atomic%, and more preferably 5 atomic% to 40 atomic%. If they are out of these ranges, the same problem as described above may occur.
Moreover, it is preferable that content of oxygen exceeds 15 atomic%, 20 atomic%-60 atomic% are preferable, and 25 atomic%-50 atomic% are more preferable. When the oxygen content is less than 15 atomic%, the oxidation resistance of the surface of the photoreceptor becomes insufficient, and when used in an image forming apparatus, the characteristics of the photoreceptor deteriorate or sufficient mechanical properties are obtained. May not be secured.

Of the elements described above, the content of elements other than nitrogen, particularly the content of group 13 elements and oxygen, is preferably satisfied at least at the outermost surface of the surface layer. The oxygen content on the outermost surface needs to exceed 15 atomic%. If the content is less than 15 atomic%, the moisture resistance, water resistance, and oxidation resistance on the surface of the photoreceptor are insufficient, and deterioration of the characteristics of the photoreceptor is unavoidable when used in an image forming apparatus. Characteristics cannot be secured.
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.
Further, for the content of each element in the entire surface layer, secondary electron mass spectrometry, Rutherford backscattering, or the like can be used.

The surface layer may be microcrystalline, polycrystalline, or amorphous, but is preferably amorphous from the viewpoint of improving the smoothness of the photoreceptor surface. The 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.
As will be described in detail later, the surface layer is laminated on the photosensitive layer using a vapor phase film formation method, so that the cross section may have a columnar structure depending on the film formation conditions and the like. However, from the viewpoint of the slipperiness of the photoreceptor surface, it is preferable not to have such a columnar structure.

  Various dopants can be added to the surface layer in order to control the conductivity type. When controlling the conductivity to n-type, for example, one or more elements selected from Si, Ge, Sn can be used, and when controlling to p-type, for example, Be, Mg, Ca, One or more elements selected from Zn and Sr can be used.

  The surface layer tends to contain many bonding defects, dislocation defects, crystal grain boundary defects, etc. in its internal structure in any case of microcrystal, polycrystal or amorphous. For this reason, hydrogen and / or a halogen element may be contained in the surface layer in order to inactivate these defects. Hydrogen and halogen elements in the surface layer are taken into bond defects in the crystal, defects at the grain boundaries, etc., and have a function of eliminating the reactive sites and performing electrical compensation. For this reason, when light is irradiated to the photoreceptor, light is absorbed in the surface layer to generate carriers, and traps related to diffusion and movement of carriers generated in the photosensitive layer are suppressed. The charging characteristics of the body surface can be further stabilized.

  When hydrogen is used, the amount of hydrogen contained in the surface layer is preferably in the range of 0.1 atomic% to 60 atomic% with respect to the entire two main elements (group 13 element, oxygen) constituting the surface layer. More preferably, it is in the range of 1 atomic% to 50 atomic%. This hydrogen amount can be measured in absolute value by HFS (Hydrogen Forward Scattering), and can also be estimated from an infrared absorption spectrum.

-Layer structure of photoconductor-
Next, the layer structure of the photoreceptor of the present invention will be described.
The photoreceptor of the present invention is not particularly limited as long as the layer structure is such that a photosensitive layer and a surface layer are laminated in this order on a conductive substrate, and an undercoat is provided between these three layers as necessary. An intermediate layer such as a layer may be provided. Further, the photosensitive layer may be two or more layers, and further may be a function separation type. Furthermore, the photoreceptor of the present invention may be a so-called amorphous silicon photoreceptor in which the photosensitive layer contains silicon atoms, or a so-called organic photoreceptor in which the photosensitive layer contains an organic polymer such as an organic photosensitive material. Hereinafter, specific examples of the layer structure of the photoreceptor of the present invention will be described in more detail 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.
The photoreceptor shown in FIG. 1 has a layer structure in which a charge generation layer 2A, a charge transport layer 2B, and a surface layer 3 are laminated in this order on a conductive substrate 1, and the photosensitive layer 2 includes the charge generation layer 2A and the charge layer. The transport layer 2B is composed of two layers.
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, 4 represents an undercoat layer, 5 represents an intermediate layer, and the others are shown in FIG. It is the same as that.
The photoreceptor shown in FIG. 2 has a layer structure in which an undercoat layer 4, a charge generation layer 2A, a charge transport layer 2B, an intermediate layer 5, and a surface layer 3 are laminated on a conductive substrate 1 in this order.
FIG. 3 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor of the present invention. In FIG. 3, 6 represents a photosensitive layer, and the others are the same as those shown in FIGS. It is.
3 has a layer structure in which an undercoat layer 4, a photosensitive layer 6, and a surface layer 3 are laminated in this order on a conductive substrate 1, and the photosensitive layer 6 is illustrated in FIGS. The charge generation layer 2A and the charge transport layer 2B shown in FIG.
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.

-Organic photoconductor-
Next, an outline of a preferable 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. Further, an intermediate layer may be provided between the photosensitive layer and the surface layer from the viewpoints of adjusting hardness, expansion coefficient, elasticity, and improving adhesion. The intermediate layer preferably exhibits intermediate characteristics with respect to both the physical properties of the surface layer and the photosensitive layer (charge transport layer in the case of the function separation type). In the case where an intermediate layer is provided, the intermediate layer may function as a layer for trapping 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 FIGS. 1 and 2, or may be a function-integrated type as shown in FIG. Good. 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 the surface layer is formed on the photosensitive layer by the method described later, in order to prevent the photosensitive layer from being decomposed by irradiation with short-wave electromagnetic waves other than heat, the surface of the photosensitive layer is formed before the surface layer is formed. 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 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, Ga _x In _(1-x) N (0 ≦ X ≦ 0.99) containing In is suitable.

Further, a layer containing an ultraviolet absorber (for example, a layer formed by applying a layer dispersed in a polymer resin or the like may be provided on the surface of the photosensitive layer.
As described above, by providing an intermediate layer on the surface of the photoreceptor before forming the surface layer, ultraviolet rays when forming the surface layer, corona discharge when the photoreceptor is used in the image forming apparatus, and various types of The influence on the photosensitive layer by short wavelength light such as ultraviolet rays from the light source can be prevented.

-Amorphous silicon photoconductor-
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 or improving adhesion can be formed on a conductive substrate, and then a photosensitive 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 the layer), for example, Si _x O (1- _x ): H, Si _x N (1- _x ): H, Si _x C (1- _x ): H, an amorphous carbon layer may be formed.

-Surface layer and formation method thereof-
Next, preferable characteristics of the surface layer other than the above-described composition and the method for forming the surface layer will be described in more detail.
As described above, the surface layer may be either amorphous or crystalline. However, in order to improve the adhesion with the photosensitive layer (or the intermediate layer) and improve the sliding of the surface of the photoreceptor, The lower layer (photosensitive layer side) is preferably microcrystalline, and the upper layer (photoreceptor surface side) is preferably amorphous.

  The surface layer may trap the charges diffused / moved from the photosensitive layer on the surface of the surface layer or may have a characteristic of trapping inside the surface layer. Alternatively, the charge may be positively injected. In the case of injection into the surface layer, it is necessary to have a structure in which charges are trapped at the interface between the photosensitive layer and the surface layer. For example, when the photosensitive layer is a function-separated type as shown in FIGS. 1 and 2, when the surface layer injects electrons with a negative charge, the surface of the charge transport layer on the surface layer side functions as a charge trap. An intermediate layer may be provided between the charge transport layer and the surface layer for blocking and trapping charge injection. The same applies to the case of positive charging.

The surface layer may also function as a charge injection blocking layer or a charge injection layer. In this case, as described above, the surface layer can also function as a charge injection blocking layer or a charge injection layer by adjusting the conductivity type of the surface layer to n-type or p-type.
When the surface layer also functions as a charge injection layer, charges are trapped on the surface of the intermediate layer or the photosensitive layer (surface on the surface layer side). In the case of negative charging, the n-type surface layer 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 functions as a charge injection blocking layer, and the p-type surface layer functions as a charge injection layer.

  Next, a method for forming the surface layer will be described. The formation of the surface layer is not particularly limited as long as at least the outermost surface can be formed so as to contain oxygen and a group 13 element. The entire surface layer directly contains oxygen and a group 13 element on the photosensitive layer. It can be formed to include. Here, when the surface layer is formed by laminating two or more layers having different compositions on the photosensitive layer, at least a layer containing oxygen and a group 13 element is formed when the uppermost layer is formed. . For example, a layer containing a group 13 element and nitrogen and a layer containing a group 13 element and oxygen can be stacked in this order on the photosensitive layer.

It is also possible to form a surface layer by once forming a film containing a group 13 element and an element other than oxygen as a main component on the photosensitive layer and then oxidizing the film from the surface. In this case, a film containing, in particular, a group 13 element and nitrogen as main components is formed on the photosensitive layer, and this film is oxidized to form a surface layer containing oxygen and a group 13 element at least on the outermost surface. can do.
As an oxidation treatment method in this case, any method of natural oxidation by leaving it in the atmosphere or forced oxidation using ozone or the like may be used, but it is used by being incorporated in an image forming apparatus as a photoreceptor. It is necessary to carry out sufficient oxidation treatment beforehand. The oxidation treatment is particularly preferably performed under intentional and controlled conditions in order to suppress variations in surface layer characteristics within the surface of the photoreceptor and quality variations between the photoreceptors.

For example, when natural oxidation is used, the oxidation is more likely to proceed in a high humidity environment. Therefore, the leaving environment when natural oxidation is performed is preferably 40% or higher, and 50% or higher. More preferably, it is more preferably 70% or more.
In addition, when the time of natural oxidation is short, if the layer near the outermost surface is not sufficiently oxidized and is used as a photoreceptor, the original performance cannot be exhibited, and the surface layer is significantly worn away. And may not be practical. From such a viewpoint, the time for performing the natural oxidation treatment is preferably 3 hours or more, preferably 10 hours or more, and more preferably 24 hours or more.

  In addition to natural oxidation, for example, forced oxidation using ozone or plasma in an oxygen atmosphere can be used as the oxidation treatment method. Such oxidation treatment can be performed in a shorter time than natural oxidation, and by selecting the oxidation conditions, a position deeper than natural oxidation (more on the photosensitive layer side) in the depth direction of the film thickness. It is easy to perform forced oxidation up to the position). Further, since the oxidation treatment can be completed in a short time, it is also useful when a film containing a group 13 element and nitrogen as main components is likely to be altered by reacting with moisture in the atmosphere.

Next, the method for forming the surface layer will be described more specifically. In forming the surface layer, a known vapor deposition method such as a plasma CVD method, a metal organic chemical vapor deposition method, or a molecular beam epitaxy method can be used. Hereinafter, a specific example will be described with reference to a drawing of an apparatus used for forming the surface layer.
FIG. 4 is a schematic diagram showing an example of a film forming apparatus used for forming the surface layer of the photoreceptor of the present invention, and FIG. 4A is a schematic cross-sectional view when the film forming apparatus is viewed from the side. FIG. 4B is a schematic cross-sectional view taken along line A1-A2 of the film formation apparatus illustrated in FIG. In FIG. 4, 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, 16 is a shower nozzle, 17 is a plasma diffusion unit, and 18 is a high frequency. A power supply unit, 19 is a flat plate electrode, 20 is a gas introduction tube, and 21 is a high-frequency discharge unit.

In the film forming apparatus shown in FIG. 4, an exhaust port 11 connected to a vacuum exhaust device (not shown) is provided at one end of the film forming chamber 10, and the side on which the exhaust port 11 of the film forming chamber 10 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 unit 21 is provided.
This plasma generator is disposed within the high-frequency discharge unit 21, the high-frequency discharge unit 21, the flat plate electrode 19 provided with a discharge surface on the exhaust port 11 side, and disposed outside the high-frequency discharge unit 21. It is comprised from the high frequency electric power supply part 18 connected to the surface on the opposite side to a discharge surface. The high-frequency discharge unit 21 is connected to a gas introduction tube 20 for supplying gas into the high-frequency discharge unit 21, and the other end of the gas introduction tube 20 is a first gas (not shown). Connected to the supply source.

  Note that the plasma generator shown in FIG. 5 may be used instead of the plasma generator provided in the deposition apparatus shown in FIG. FIG. 5 is a schematic diagram showing another example of the plasma generating apparatus that can be used in the film forming apparatus shown in FIG. 4, and is a side view of the plasma generating apparatus. In FIG. 5, 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. 5). 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, and the substrate holder 13 is arranged 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 is adapted to be attached to the base rotating part 12 via During film formation, the substrate 14 can be rotated in the circumferential direction by rotating the substrate rotating unit 12. As the substrate 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.

The formation of the surface layer can be performed, for example, as follows. First, N ₂ is introduced into the high-frequency discharge unit 21 from the gas introduction tube 20, and a 13.56 MHz radio wave is supplied from the high-frequency power supply unit 18 to the plate electrode 19. 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.
Next, trimethylgallium gas diluted with hydrogen using hydrogen as a carrier gas is introduced into the film forming chamber 10 through the gas introduction tube 15 and the shower nozzle 16, thereby hydrogen, nitrogen and gallium are introduced into the surface of the substrate 14. A containing film can be formed.

Here, in order to introduce oxygen into the film, a method of incorporating oxygen atoms during film formation or a method of oxidizing with oxygen after film formation can be used.
In the former case, a surface layer containing oxygen, nitrogen, and a group 13 element can be formed by mixing nitrogen gas with an oxygen gas or a gas containing oxygen such as N ₂ O or H ₂ O. . Further, oxygen gas or a gas containing oxygen such as N ₂ O or H ₂ O is mixed with a rare gas such as He or Ar to generate plasma, which is reacted with an organometallic gas such as trimethylgallium gas. It is also possible to form a surface layer containing
On the other hand, in the latter case, it can be performed in a vacuum or in the atmosphere. In the case of performing in vacuum, for example, oxygen can be taken into the film by performing high frequency discharge using oxygen gas diluted with a rare gas or the like. Furthermore, as another method for incorporating oxygen into the film, a known method such as a thermal diffusion method or an ion implantation method can be employed. Alternatively, the substrate 14 on the surface of which a film containing hydrogen and containing nitrogen and gallium is formed can be oxidized by simply exposing it to air in the atmosphere or exposing it to an oxygen atmosphere at atmospheric pressure.

The formation temperature of the surface layer at the time of film formation is not particularly limited, but it is preferably 50 to 350 ° C. when producing an amorphous silicon photoreceptor, and from 20 ° C. when producing an organic photoreceptor. It is preferable to form at 100 ° C.
In the case of producing an organic photoreceptor, the substrate temperature during the formation of the surface layer is preferably 150 ° C. or less, and more preferably 100 ° C. or less. Even when the substrate temperature is 150 ° C. or lower, if the temperature is higher than 150 ° C. due to the influence of plasma, the photosensitive layer may be damaged by heat. Therefore, the substrate temperature should be set in consideration of such influence. Is preferred.
The substrate temperature may be controlled by a method not shown, or may be left to a natural temperature rise during discharge. When heating the substrate 14, a heater may be installed outside or inside the substrate 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 substrate temperature due to the discharge, it is effective to adjust the high-energy gas flow that strikes the surface of the substrate 14. In this case, conditions such as the gas flow rate, discharge output, and pressure are adjusted so as to achieve the required temperature.

In addition, when hydrogen is added to the surface layer, hydrogen gas can be introduced from the gas introduction pipes 15 and 20. In this case, it can be mixed and introduced together with a gas containing an essential component constituting the surface layer such as nitrogen or trimethylgallium gas.
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 forming the surface layer, trimethylindium is introduced into the film formation chamber 10 through the gas introduction tube 15 and the shower nozzle 16, thereby forming a film containing nitrogen and indium on the substrate 14. In this case, this film can be absorbed when the film is continuously formed, and the ultraviolet rays that deteriorate the photosensitive layer can be absorbed. 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 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.

When an organometallic compound containing hydrogen atoms is used as a supply material for group 13 atoms and a film mainly containing group 13 atoms, hydrogen atoms, and nitrogen atoms is formed, active hydrogen and activated nitrogen activated by plasma are It can be obtained as described below.
For example, in a film forming apparatus as shown in FIG. 4, when hydrogen gas and nitrogen gas are introduced into the film forming apparatus from different positions, the hydrogen gas activation state and the nitrogen gas activation state are A plurality of plasma generators may be provided so that each can be controlled independently. In contrast to this, as a supply material for hydrogen and nitrogen, a gas containing both nitrogen atoms and hydrogen atoms, such as NH ₃ , or a mixture of nitrogen gas and hydrogen gas is used. It may be activated by plasma.
Furthermore, as a hydrogen source of hydrogen activated by plasma, it is also possible to use hydrogen produced free by activating an organometallic compound containing hydrogen atoms once introduced into the film forming apparatus.

By the method described above, activated hydrogen, nitrogen, and group 13 atoms are present on the substrate, and the activated hydrogen is further converted into carbonized carbon such as methyl group or ethyl group constituting the organometallic compound. It has the effect of desorbing hydrogen of a hydrogen group as a molecule. Therefore, a surface layer made of a hard film in which hydrogen, nitrogen, and a group 13 element form a three-dimensional bond is formed on the surface of the substrate.
Unlike the sp2-bonding carbon atoms contained in silicon carbide, such a hard film is transparent because Ga and N form sp3 bonds like the carbon atoms constituting the tiremond. In addition, this hard film can be made into a film containing oxygen by natural oxidation or an oxidation treatment such as oxygen or ozone after the film is formed. This film is transparent and hard, and the surface of the film is water repellent or slippery. High friction and low friction.

The plasma generating means of the film forming apparatus shown in FIG. 4 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. You may use the apparatus of a system. 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.

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. 4 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 tube 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 14 in the film forming chamber 10 and the plasma diffusion portion 17, and this film is used to form the film forming chamber. It is also possible to cause a discharge in 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.

In forming the surface layer, in addition to the above-described methods, a normal metal organic vapor phase epitaxy method or molecular beam epitaxy method can be used. However, in the film formation by these methods, active nitrogen and / or Alternatively, it is effective to use active hydrogen. 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.

-Conductive substrate and photosensitive layer-
Next, regarding 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 intermediate layer provided as necessary, the electrophotographic photosensitive member of the present invention has a function separation type. The case of an organic photoreceptor having the above photosensitive layer 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, JIS 1000 series, 3000 series, 6000 series aluminum or aluminum alloy) 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 to 20% by mass, bath temperature: 5 to 25 ° C., current density: 1 to 4 A / dm ² , electrolytic voltage: 5 to 30 V, treatment time: about 5 to 60 minutes. It is performed under conditions, but is not limited to this.

  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 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 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 properties 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. When forming the undercoat layer, it is preferable to form it so that the film thickness is in the range of 0.1 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 electron-withdrawing substituents 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, it is preferable that the above-mentioned metal oxide fine particles have a powder resistance of about 10 ² 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 to} 1.0 × 10 ⁻³ times 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'dimethylaminophenyl) 1,5,6-di- (4'-methoxyphenyl) -1,2,4-triazine, 1,2,4-triazine derivatives, 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 razone, 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 it is usually preferably within the range of 3000 to 300,000 in terms of viscosity average molecular weight. Within the range of ~ 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 compounding ratio of the charge transport material and the binder resin is preferably in the range of 10: 1 to 1: 5. The film thickness of the charge transport layer is generally preferably in the range of 5 to 50 μm, more preferably in the range of 10 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.

Among organic sulfur antioxidants, 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 compounding 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 to 50 μm, more preferably in the range of 10 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. to 200 ° C. 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 A crystalline form of chlorogallium phthalocyanine having a diffraction peak in 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, silicon-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 to 5 μm, and more preferably in the range of 0.05 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, 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 with a relatively low erosion property of the lower layer, the selection range of the solvent can be expanded.

-Intermediate layer-
As the intermediate layer, for example, when charging the surface of the photosensitive member with a charger, the charged electric charge is prevented from being injected from the surface of the photosensitive member to the conductive substrate of the photosensitive member which is the counter electrode. Therefore, a charge injection blocking layer can be formed between the surface protective layer and the charge generation layer as necessary.
As the material for the charge injection blocking layer, it is possible to use general-purpose resins such as silane coupling agents, titanium coupling agents, organic zirconium compounds, organic titanium compounds, other organometallic compounds, polyesters, and polyvinyl butyral as listed above. it can. The film thickness of the charge injection blocking layer is appropriately set within the range of about 0.001 to 5 μm in consideration of the film forming property and the carrier blocking property.

(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. Specifically, the process cartridge includes a group consisting of the photoconductor of the present invention, a charging unit, a developing unit, a cleaning unit and a charge eliminating unit. It is preferable that at least one selected from the above is integrally formed and 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 that forms an electrostatic latent image by exposing the surface of the photoreceptor charged by the charging unit, a developing unit that develops the electrostatic latent image with a developer containing toner, and a toner image It is preferable to have a configuration provided with a transfer means for transferring 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.

  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
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, whereby a film thickness of 1.0 μm was subtracted. 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 the compound represented by the following structural formula (1) and 3 parts by mass of the polymer compound (weight average molecular weight 39000) represented by the following structural formula (2) are dissolved in 20 parts by mass of chlorobenzene. Thus, a coating liquid for forming a charge transport layer was obtained.

  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 surface layer-
The surface layer was formed on the surface of the non-coated photoconductor 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 H ₂ gas are mixed at a ratio of 1: 1 is supplied from the gas introduction tube 20 into the high-frequency discharge part 21 provided with the flat plate electrode 19 having a diameter of 50 mm (1000 sccm (nitrogen gas 500 sccm, hydrogen gas Gas (500 sccm) was introduced, and a radio wave of 13.56 MHz was 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 with a tuner, and discharging was performed from the plate 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 is supplied from the shower nozzle 16 to the plasma diffusion portion 17 in the film forming chamber 10 through the gas introduction pipe 15 at a flow rate of 0. It introduced so that it might become 3 sccm. 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 photoconductor was formed for 60 minutes while rotating at a speed of 5 rpm to form a film having a thickness of 0.2 μm. In the film formation, the non-coated photoconductor was not heat-treated. Further, the color of the thermo-tape previously attached to the inner peripheral surface of the non-coated photoreceptor before film formation was confirmed after film formation and found to be 35 ° C.
Subsequently, the non-coated photoconductor after film formation is left in a normal room temperature and normal humidity environment (temperature of about 25 ° C., humidity of about 50%) for 24 hours, and is subjected to oxidation treatment by natural oxidation, and the surface of the charge transport layer An organic photoreceptor provided with a surface layer was obtained.

-Analysis and evaluation of surface layer-
At the time of film formation on the surface of the non-coated photoreceptor, infrared absorption spectrum measurement of the film formed on the Si substrate at the same time was carried out on the film immediately after film formation. As a result, Ga-H bond, Ga-N bond and N-H bond were obtained. The resulting peak was confirmed. In addition, even when the film formed on the Si substrate was measured for the film after the oxidation treatment in the same manner as described above, the peak intensity due to these three bonds decreased to 1/2 of the Ga-H bond. The peak was confirmed at the same intensity. From these results, it was found that the surface layer contained gallium, nitrogen, and hydrogen.
In addition, the surface of the film formed on the Si substrate was measured by XPS (X-ray photoelectron spectroscopy) after being left for about 24 hours after film formation in a normal temperature and humidity environment similar to the above and in an environment where contamination is difficult to adhere. As a result, oxygen was 60 atomic%, Ga was 40 atomic%, and nitrogen was not recognized. In addition to this result, the resolution in the depth direction by XPS measurement is about several nanometers on the outermost surface, and from the result of the infrared absorption spectrum in which the entire surface layer is the object of measurement, at least the outermost surface of the surface layer is oxygen-rich. It is in a nitrogen-poor state, and the oxygen atom concentration in the surface layer thickness direction decreases toward the charge transport layer side (the nitrogen atom concentration increases toward the charge transport layer side). all right.

Furthermore, when the hydrogen content in the film was measured by HFS (Hydrogen Forward Scattering) for the sample after XPS measurement, it was 35 atomic% and obtained by RHEED (reflection high-energy electron diffraction) measurement. The diffraction image showed no dots or lines, indicating that the film was amorphous.
The film formed on the Si substrate immediately after the film was dissolved when immersed in water, but the film after being left in a normal room temperature and humidity environment for 1 week did not dissolve even when immersed in water. There was no damage even when rubbed with steel.
From the above analysis and evaluation results, the surface layer formed through film formation and oxidation treatment is amorphous and has a composition containing oxygen in addition to hydrogen, nitrogen, and gallium. It was found that the film had a distribution in which the concentration of oxygen atoms relative to the direction was richest on the outermost surface and decreased toward the charge transport layer side.

-Evaluation-
Next, the electrophotographic characteristics of the organic photoreceptor provided with this surface layer were evaluated. First, exposure light (light source: semiconductor laser, wavelength 780 nm, output 5 mW) is applied to the uncoated photoreceptor before the surface layer formation and the photoreceptor provided with the surface layer by a scorotron charger. The residual potential on the surface of the photoconductor after irradiation was measured while scanning the surface of the photoconductor rotated at 40 rpm in a charged state. As a result, it was found that the organic photoreceptor provided with the surface layer was -50 V or less, which was practically no problem, while the non-coated photoreceptor was -20 V.
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 this surface layer was attached to DocuCenter Color 500 manufactured by Fuji Xerox Co., Ltd., and 10000 continuous prints were evaluated under a high temperature and high humidity environment (28 ° C., 80%). As a reference for image quality evaluation, a non-coated photoconductor was also attached to the DocuCenter Color 500 to form a similar image.
As a result, a resolution of 10 lines / mm is obtained for an image that is clear and has no image blur at the halftone dot portion, similar to the image at the initial stage of the print test formed using the non-coated photoconductor both at the initial stage of the print test and after the end of the print test. Could get. Further, when the surface of the photoreceptor after the print test was visually observed, no scratch was generated, and the wear was 0 μm. Also, no adhesion of discharge products was confirmed. On the other hand, in the non-coated photoconductor, scratches were generated on the surface of the photoconductor after the print test, and discharge products were also adhered. Wear was 0.3 μm.
From the above results, it was found that the photoconductor provided with the surface layer has improved durability and is practically satisfactory in terms of image quality such as sensitivity and image blur.

( Reference example )
For the non-coated photoreceptor produced in the same manner as in Example 1, a surface layer was formed by the following procedure using an apparatus having the same 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, nitrogen gas and H ₂ gas are mixed at a ratio of 3: 1, and the gas is supplied from the gas introduction tube 20 into the high-frequency discharge part 21 provided with the plate electrode 19 having a diameter of 50 mm (1000 sccm (nitrogen gas 750 sccm, hydrogen gas A gas of 250 sccm) was introduced, and a radio wave of 13.56 MHz was set to an output of 100 W by the high frequency power supply unit 18 and a matching circuit (not shown in FIG. 1), and matching was performed with a tuner to discharge from the plate electrode 19. The reflected wave at this time was 0 W.
Next, a mixed gas containing trimethylaluminum gas using hydrogen gas as a carrier gas is supplied from the shower nozzle 16 to the plasma diffusion portion 17 in the film forming chamber 10 through the gas introduction pipe 15 at a flow rate of 1. It introduced so that it might become 0 sccm. The plasma is arranged in a slit shape through 17 diffusion portions. 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 formed for 20 minutes while rotating at a speed of 10 rpm to form a film having a thickness of 0.2 μm. In the film formation, the heat treatment was not performed as in Example 1.
Subsequently, a mixed gas of helium and oxygen (helium 100 sccm, oxygen 10 sccm) is introduced into the high-frequency discharge unit 21 from the gas introduction tube 20 to the non-coated photoreceptor after film formation, and the high-frequency power supply unit 18 and With a matching circuit (not shown in FIG. 1), a 13.56 MHz radio wave was set to an output of 100 W, matching was performed with a tuner, discharge was performed from the plate electrode 19, and oxidation treatment was performed for 10 minutes. Thereafter, the photoreceptor on which the surface layer having been subjected to the oxidation treatment was formed was taken out from the film forming chamber 10.

-Analysis and evaluation of surface layer-
At the time of film formation / oxidation treatment on the surface of the non-coated photoreceptor, infrared absorption spectrum measurement of the film formed / oxidation treatment on the Si substrate was carried out, resulting from Al—H bond, Al—N bond and N—H bond. The peak to be confirmed was confirmed. From these results, it was found that the surface layer contained Al, N, and hydrogen.
Further, the surface of the film formed on the Si substrate was measured by XPS (X-ray photoelectron spectroscopy). As a result, oxygen was 70 atomic%, Al was 30 atomic%, nitrogen was not observed, and the film had the most It was found that aluminum oxide was formed on the surface. In addition to this result, the resolution in the depth direction by XPS measurement is about several nanometers on the outermost surface, and from the result of the infrared absorption spectrum in which the entire surface layer is the object of measurement, at least the outermost surface of the surface layer is oxygen-rich. It is in a nitrogen-poor state, and the oxygen atom concentration in the surface layer thickness direction decreases toward the charge transport layer side (the nitrogen atom concentration increases toward the charge transport layer side). all right.

Furthermore, when the hydrogen content in the film was measured by HFS (Hydrogen Forward Scattering) for the sample after XPS measurement, it was 40 atomic% and was obtained by RHEED (reflection high-energy electron diffraction) measurement. The diffraction image showed no dots or lines, indicating that the film was amorphous. The film formed on the Si substrate was transparent and was not damaged even when rubbed with stainless steel.
From the above analysis and evaluation results, the surface layer formed through film formation and oxidation treatment is amorphous and has a composition containing oxygen in addition to hydrogen, nitrogen, and aluminum. It was found that the film had a distribution in which the concentration of oxygen atoms relative to the direction was richest on the outermost surface and decreased toward the charge transport layer side.

Next, the electrophotographic characteristics of the organic photoreceptor provided with this surface layer were evaluated. First, the surface after irradiating the surface of the photoreceptor with the exposure light in the same manner as in Example 1 for the non-coated photoreceptor before the surface layer formation and the photoreceptor provided with the surface layer. The residual potential of was measured. As a result, it was found that the organic photoreceptor provided with the surface layer was -30 V or less, which was practically no problem, while the non-coated photoreceptor was -20 V.
As for the influence on the sensitivity, the wavelength of the light source was evaluated over the entire visible region from the infrared region, but there was almost no difference between the non-coated photoreceptor before the surface layer formation and the photoreceptor provided with the surface layer, It was found that there was no decrease in sensitivity due to the provision of the surface layer.
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 surface layer was attached to DocuCenter Color 500 manufactured by Fuji Xerox Co., Ltd., and print evaluation was performed in the same manner as in Example 1.
As a result, it is possible to obtain a clear image with 10 lines / mm and no image blur, which is the same as the image in the initial stage of the print test formed using the non-coated photoconductor both at the initial stage of the print test and after the end of the print test. I was able to. Further, when the surface of the photoreceptor after the print test was visually observed, no scratch was generated, and the wear was 0 μm. No adhesion of discharge products was confirmed. On the other hand, in the non-coated photoconductor, scratches were generated on the surface of the photoconductor after the print test, and discharge products were also adhered.
From the above results, it was found that the photoconductor provided with the surface layer has improved durability and is practically satisfactory in terms of image quality such as sensitivity and image blur.

(Example 2 )
-Formation of surface layer-
On the same Al substrate as used in Example 1, a 3 μm-thick charge injection blocking layer made of n-type Si ₃ N, an i-type amorphous silicon photosensitive layer having a thickness of 20 μm, and a p-type A device having the structure shown in FIG. 4 similar to that of the first embodiment is formed on the surface of a negatively charged amorphous silicon photosensitive member in which a charge injection blocking surface layer made of Si ₂ C and having a thickness of 0.5 μm is formed in this order. A film containing hydrogen, nitrogen and gallium was formed under the same conditions as in Example 1.
Subsequently, the amorphous silicon photoconductor subjected to the film forming process was attached to a rotating device equipped with a corotron charger and rotated at 40 rpm. In a bright room under a room air atmosphere (temperature 25 ° C., humidity 50%), a voltage of −6 kV was applied to the corotron charger and exposed to an ozone atmosphere for 1 hour to oxidize the surface to form a surface layer.
At the time of film formation / oxidation treatment on the amorphous silicon photoreceptor, a sample in which only a similar film (surface layer) was formed using a Si wafer substrate was also produced.

When an infrared absorption spectrum of a film obtained by film formation / oxidation treatment on a Si substrate was measured, peaks due to Ga—H bonds, Ga—N bonds and N—H bonds were confirmed, and in the surface layer It was found that gallium, nitrogen and hydrogen were contained.
Further, when measured by XPS (X-ray photoelectron spectroscopy), it was found that oxygen was 70 atomic%, Ga was 30 atomic%, nitrogen was not recognized, and gallium oxide was formed on the outermost surface. . In addition to this result, the resolution in the depth direction by XPS measurement is about several nanometers on the outermost surface, and from the result of the infrared absorption spectrum in which the entire surface layer is the object of measurement, at least the outermost surface of the surface layer is oxygen-rich. It is in a nitrogen-poor state, and the oxygen atom concentration in the surface layer thickness direction decreases toward the charge transport layer side (the nitrogen atom concentration increases toward the charge transport layer side). all right.

Furthermore, the hydrogen content in the film was measured by HFS (Hydrogen Forward Scattering) and found to be 35 atomic%. The diffraction image obtained by the RHEED (reflection high-energy electron diffraction) measurement is completely dotted. No lines were observed and the film was found to be amorphous.
From the above analysis and evaluation results, the surface layer formed through film formation and oxidation treatment is amorphous and has a composition containing oxygen in addition to hydrogen, nitrogen, and gallium. It was found that the film had a distribution in which the concentration of oxygen atoms relative to the direction was richest on the outermost surface and decreased toward the charge transport layer side.

-Evaluation-
Next, the electrophotographic characteristics of the amorphous photoreceptor provided with this surface layer were evaluated. First, exposure light (light source: semiconductor) is applied to the amorphous photoreceptor before forming the surface layer (hereinafter sometimes referred to as “non-coated amorphous photoreceptor”) and the amorphous photoreceptor provided with the surface layer. The residual potential on the surface of the photoreceptor after irradiation was measured while scanning the surface of the photoreceptor rotated at 40 rpm with a scorotron charger charged with a laser, a wavelength of 650 nm, and an output of 5 mW. As a result, it was found that the non-coated amorphous photoconductor is -20V, while the amorphous silicon photoconductor provided with the surface layer is -60V or less, which is a practically acceptable level.
As 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 amorphous photoconductor and the amorphous silicon photoconductor provided with the surface layer. It was found that there was no decrease in sensitivity due to the provision of
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. Further, the surface property was smoother and more slippery than the non-coated amorphous silicon photoreceptor.

Next, the photoconductor provided with this surface layer is attached to DocuCenter Color 500 manufactured by Fuji Xerox Co., Ltd., which is prepared for an amorphous silicon photoconductor, and 2000 continuous prints are performed under a high temperature and high humidity environment (28 ° C. and 85%). Evaluation was performed. As a reference for image quality evaluation, a non-coated amorphous silicon photoconductor was also attached to the DocuCenter Color 500 prepared for the above amorphous silicon photoconductor to form a similar image.
As a result, it is possible to obtain an image with a resolution of 10 lines / mm that is clear and free from image blur, similar to the image in the initial stage of the print test formed using the non-coated amorphous silicon photoconductor both at the initial stage of the print test and after the end of the print test. I was able to. Further, when the surface of the amorphous silicon photoreceptor provided with the surface layer after the print test was visually observed, no scratch was generated, no adhesion of the discharge product was confirmed, and the initial slip was maintained. On the other hand, in the non-coated amorphous silicon photoconductor, discharge products adhered to the surface of the photoconductor after the print test, and an image blur with a resolution of 1 line / mm or less was generated.
From the above results, the amorphous silicon photoconductor provided with the surface layer is equivalent to the non-coated amorphous silicon photoconductor in terms of hardness as compared with the non-coated amorphous silicon photoconductor, and also in terms of sensitivity and discharge. It was found that image blur due to product adhesion could be prevented and that it could withstand long-term use.

(Comparative Example 1)
For the non-coated photoreceptor produced in the same manner as in Example 1, a surface layer was formed by the following procedure using an apparatus having the same 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, 100 sccm of methane gas is introduced from the gas introduction pipe 20 into the high frequency discharge unit 21 provided with the flat plate electrode 19 having a diameter of 50 mm, and the high frequency power supply unit 18 and a matching circuit (not shown in FIG. 1) A 56 MHz radio wave was set to an output of 300 W, matching was performed with a tuner, and discharge was performed from the plate electrode 19. The reflected wave at this time was 0 W.
At this time, the reaction pressure in the film forming chamber 10 measured with a Baratron vacuum gauge was 13 Pa.

In this state, the non-coated photoconductor was formed for 60 minutes while rotating at a speed of 10 rpm to form a diamond-like carbon film having a thickness of 0.2 μm. In the film formation, the heat treatment was not performed as in Example 1. Thereafter, the photoreceptor provided with the diamond-like carbon film as a surface layer was taken out from the film forming chamber 10.
The surface of the photoreceptor was dark brown.

Next, the electrophotographic characteristics of the organic photoreceptor provided with this surface layer were evaluated. First, photosensitivity after irradiating the surface of the non-coated photoconductor before forming the surface layer and the photoconductor provided with the surface layer with light for exposure in the same manner as in Example 1. The residual potential on the body surface was measured. As a result, the non-coated photoreceptor was -20V, while the organic photoreceptor provided with the surface layer was -100V, and the residual potential was increased.
In addition, the influence on the sensitivity was evaluated by measuring the wavelength of the light source from the infrared region to the entire visible region, but the non-coated photoconductor before the surface layer was formed and the photoconductor provided with the surface layer from the short wavelength to the long wavelength. The sensitivity was greatly reduced, and 1/10 and 780 nm long wavelength was desensitized by 1/3 at short wavelength.

Next, the photoconductor provided with the surface layer was attached to DocuCenter Color 500 manufactured by Fuji Xerox Co., Ltd., and print evaluation was performed in the same manner as in Example 1.
As a result, it was found that the printed image had a low contrast and the image density was insufficient, and image blurring was observed after the print test was completed, which is problematic in terms of image quality.

FIG. 2 is a schematic cross-sectional view illustrating an example of a layer configuration of a photoreceptor of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of the layer structure of the photoreceptor of the present invention. FIG. 6 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 a surface layer of a photoreceptor according to the invention. It is a schematic diagram which shows the other example of the plasma generator which can be utilized in the film-forming apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive substrate 2 Photosensitive layer 2A Charge generation layer 2B Charge transport layer 3 Surface layer 4 Undercoat layer 5 Intermediate layer 6 Photosensitive layer 10 Film forming chamber 11 Exhaust port 12 Substrate rotating unit 13 Substrate holder 14 Substrate 15 Gas introduction tube 16 Shower Nozzle 17 Plasma diffusion unit 18 High frequency power supply unit 19 Flat plate electrode 20 Gas introduction tube 21 High frequency discharge unit 22 High frequency coil 23 Quartz tube

Claims (4)

In an electrophotographic photoreceptor including a conductive substrate, a photosensitive layer, and a surface layer, and the photosensitive layer and the surface layer are laminated in this order on the conductive substrate.
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 by performing XPS measurement by irradiating the outermost surface with 10 kV, 20 mA using MgKα rays as an X-ray source. An electrophotographic photosensitive member characterized by being at least atomic% .   The electrophotographic photosensitive member according to claim 1, wherein a concentration distribution of oxygen contained in the surface layer in the thickness direction of the surface layer decreases toward the photosensitive layer side. An electrophotographic photosensitive member comprising a conductive substrate, a photosensitive layer, and a surface layer, wherein the photosensitive layer and the surface layer are laminated in this order on the conductive substrate; a charging unit; a developing unit; a cleaning unit; In the process cartridge which integrally has at least one selected from the group consisting of static elimination means and is detachable from the image forming apparatus main body,
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 by performing XPS measurement by irradiating the outermost surface with 10 kV, 20 mA using MgKα rays as an X-ray source. A process cartridge characterized by at least atomic percent . An electrophotographic photoreceptor comprising a conductive substrate, a photosensitive layer, and a surface layer, wherein the photosensitive layer and the surface layer are laminated in this order on the conductive substrate, and charging the surface of the electrophotographic photoreceptor A charging means; an exposure means for exposing the surface of the electrophotographic photosensitive member charged by the charging means to form an electrostatic latent image; and developing the electrostatic latent image with a developer containing toner to form a toner image. In an image forming apparatus comprising: a developing unit that forms; and a transfer unit that transfers the toner image to a recording medium.
At least the outermost surface of the surface layer contains oxygen and gallium, and the oxygen content is 60 by performing XPS measurement by irradiating the outermost surface with 10 kV, 20 mA using MgKα rays as an X-ray source. An image forming apparatus comprising at least atomic percent .

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