JP2009080266A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which can suppress irregularity of density in an image, irregularity of photosensitivity in an electrophotographic photoreceptor causing irregularity of color and irregularity of residual potential, which has the excellent and uniform photosensitivity over the whole surface, which has extremely high stability for water and the stability for environmental change and, even when performing image formation at high speed on recording media of a variety of thicknesses and materials while increasing repetition times, which can suppress damage of the surface and is excellent in water resistance, weather resistance and durability. <P>SOLUTION: The electrophotographic photoreceptor has at least a photoconductive layer and a surface layer disposed on a cylindrical conductive base, wherein the surface layer contains magnesium atom, fluorine atom and oxygen atom as principal constitutional atoms and the principal constitutional atoms satisfy a composition formula MgFxOy (1) (in the formula, x denotes a number of ≥1.30 and ≤2.10; and y denotes a number of ≥0.050 and ≤0.500). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor used in an electrophotographic apparatus.

  As a photosensitive member of an electrophotographic photosensitive member (hereinafter also referred to as a photosensitive member) used in an electrophotographic apparatus, an amorphous deposited film containing silicon atoms as main constituent atoms, for example, amorphous silicon containing hydrogen or halogen (hereinafter referred to as amorphous silicon). , Also referred to as a-Si.) The deposited film has high performance, high durability, no pollution, and has been put into practical use. A photoconductor using such an a-Si deposited film has been proposed having various layer configurations in accordance with required performance. Of these, the surface layer is an important layer that imparts characteristics such as abrasion resistance, charge retention, and environmental resistance to the photoreceptor.

  As fine image formation of an electrophotographic apparatus progresses, the wavelength of image exposure is shortened, and a surface layer is required that has a wide band gap that transmits light with less absorption especially for short wavelength light. Since metal fluorides, metal oxides, and metal nitrides generally have high hardness and a relatively large band gap with respect to short-wavelength light, their use for surface layer materials has been studied.

  Specifically, it has been reported that the surface layer using magnesium fluoride suppresses the occurrence of image blur and image flow, and that there is almost no potential fluctuation due to wear (Patent Document 1). In addition, F / Mg (atomic weight ratio) in the surface layer is set to 1.50 to 1.95, and the F content is reduced relative to F / Mg = 2.00 which is the stoichiometric composition ratio of magnesium fluoride. A surface layer (Patent Document 2) that prevents fluctuations in residual potential and generation of scratches has been reported.

  In addition, with the colorization of electrophotographic devices, there is an increasing demand for finer image formation, and electrophotographic images are required to have the same image quality as silver halide photographs, and the demand for color unevenness is becoming more severe than ever. . Nonuniformity of photosensitivity of the photoconductor, that is, nonuniformity in photosensitivity, appears in the resulting image, particularly as uneven density in the halftone part, but in color images, the nonuniformity in density appears as uneven color. Therefore, there is a demand for a photoconductor that has a non-uniform photosensitivity on a higher standard than a black and white image. In recent years, the advancement of electrophotography in the field of light printing, represented by print-on-demand, has been put into practical use. It has been demanded.

  When each layer of such a photoreceptor is manufactured by deposition film growth, the distance and angle from the source of the source material are often different in a photoreceptor having a curved surface with a relatively large area. It is not always easy to control the process uniformly over the entire area. For this reason, although the atomic composition ratio is substantially the same, the film growth process is often not uniform throughout the film. As a result, unevenness in light sensitivity such as transmission of light due to nonuniformity of structural defects or the like occurs in the photoconductor, and in some cases, residual potential unevenness appears, and a good image may not be obtained.

Also, when image formation is repeated at high speed, friction with a separation claw that separates copy paper from the surface of the photoreceptor, entrapment of rarely occurring foreign matter, or a mixture of paper of different thickness and paper quality is used. The surface of the photoreceptor may be damaged due to a change in load or the like. This type of scratch is more frequently generated in a high temperature and high humidity environment where the load increases. In particular, in order to cope with high definition, in an electrophotographic apparatus having an optical system in which the wavelength of image exposure is shortened or the spot diameter is reduced, scratches generated on the photoreceptor are highly likely to appear on the image, Higher scratch resistance and durability are demanded for the photoreceptor than ever before. In such a background, the surface layer provided on the photoreceptor is improved in durability, has no structural defects, suppresses light absorption for short-wavelength light, and increases the transmittance. Is requested.
JP 2003-29437 A JP 2006-106341 A

  An object of the present invention is for an electrophotographic apparatus that suppresses uneven photosensitivity and residual potential unevenness in an electrophotographic photosensitive member that causes density unevenness and color unevenness in an image and has good and uniform photosensitivity over the entire surface. The object is to provide a photoreceptor. Furthermore, it is extremely stable against water, has stability against environmental changes, and can suppress damage to the surface even when image formation is performed at high speed and with a large number of repeated recordings of various thicknesses and materials. An object of the present invention is to provide an electrophotographic photoreceptor excellent in water resistance, weather resistance and durability.

  The inventors of the present invention have made extensive studies on the cause of generation of unevenness in photosensitivity, unevenness in residual potential, and scratches in the surface layer of the electrophotographic photoreceptor. As described above, the surface layer obtained by the growth of the deposited film is caused by the atomic composition, and even if the atomic composition ratio is substantially the same, the structural defect causes uneven photosensitivity and residual potential unevenness. Although it occurs, this non-uniformity in photosensitivity and non-uniformity in residual potential often appear randomly in the circumferential direction. The cause of this appearance is not clear. However, when a single compound is used as a raw material, this phenomenon may occur in any surface layer using any material, regardless of the raw material. When it was set as the 2 or more types of compound mixed, the knowledge that it was suppressed was acquired.

  And the characteristic which a magnesium atom, a fluorine atom, and an oxygen atom provide to a surface layer was verified, and those atomic ratios for obtaining a surface layer exhibiting the characteristics of these atoms were searched.

  Scratch improves when both fluorine atom and oxygen atom are contained at a certain atomic ratio or more with respect to magnesium atom, but fluorine atom is dominant and the atomic ratio of fluorine atom to magnesium atom is too small Not only in the case of being oversized, there is a tendency for scratches to occur. On the other hand, if the oxygen atom is contained at a certain atomic ratio relative to the magnesium atom, the effect on scratches is not improved even if it is contained at a higher atomic ratio. This is presumably because the deposited film becomes brittle when the atomic ratio of fluorine atoms increases due to the difference in binding energy between magnesium atoms and fluorine atoms and between magnesium atoms and oxygen atoms.

  In addition, with regard to unevenness in light sensitivity, an effect appears when both fluorine atoms and oxygen atoms are contained in a certain atomic ratio or more with respect to magnesium atoms. Even when the atomic ratio of either a fluorine atom or an oxygen atom is extremely small, the unevenness in photosensitivity tends to deteriorate. In addition, when the atomic ratio of oxygen atoms exceeds a certain level, unevenness in photosensitivity tends to appear. This is because it is necessary to contain fluorine atoms and oxygen atoms at a certain atomic ratio in order to offset structural defects, and due to the difference in binding energy of fluorine atoms or oxygen atoms to magnesium atoms, If the atomic ratio of atoms increases, defects appear to be generated.

  The residual potential unevenness tends to occur when the atomic ratio of fluorine atoms is large with respect to magnesium atoms. It is expected that this is because the runnability of carriers is impaired by excessive incorporation of fluorine atoms.

  In addition to the influence on these characteristics, when the atomic ratio of oxygen atoms to magnesium atoms exceeds a certain level, the stability to moisture tends to be impaired. This is thought to be due to the appearance of the characteristics of magnesium oxide that causes a basic reaction with water. However, even if it contains a small amount of fluorine atoms, it is much more than the atomic ratio at which oxygen atoms are saturated with respect to magnesium atoms. Such a tendency may appear even at a low atomic ratio. Specifically, this tendency starts to appear in a region where y exceeds 0.2 in the composition formula (1), and becomes more prominent in a region where y exceeds 0.5. In this case, spots due to water droplets are generated on the photosensitive member. For scratches and uneven photosensitivity, when the atomic ratio of fluorine atoms to magnesium atoms is small, the characteristics are improved by increasing the atomic ratio of oxygen atoms, but the occurrence of the above-mentioned spots is not a problem. When y in (1) was in the range of 0.5 or less, no significant effect appeared.

  The inventors have found a specific range of fluorine atom content and oxygen atom content with respect to magnesium atoms, in which the characteristics of each atom are exhibited in the surface layer, and based on this knowledge, the present invention has been completed.

That is, the present invention provides an electrophotographic photoreceptor having at least a photoconductive layer and a surface layer on a conductive substrate, the surface layer containing magnesium atoms, fluorine atoms, and oxygen atoms as main constituent atoms. Constituent atom is composition formula (1)
MgF _x O _y (1)
(Wherein x represents a number of 1.30 or more and 2.10 or less, and y represents a number of 0.050 or more and 0.500 or less). .

  The electrophotographic photoreceptor of the present invention suppresses unevenness in photosensitivity that causes unevenness in density and color in an image and unevenness in residual potential, and has good and uniform photosensitivity over the entire surface. Furthermore, the electrophotographic photoreceptor of the present invention is extremely stable against water, has stability against environmental changes, and forms images by increasing the number of repetitions on recording materials of various thicknesses and materials at high speed. Even when performed, the surface damage can be suppressed, and the water resistance, weather resistance, and durability are excellent.

  The electrophotographic photoreceptor of the present invention has at least a photoconductive layer and a surface layer on a conductive substrate.

  The conductive substrate used for the electrophotographic photoreceptor of the present invention has a strength capable of supporting the photoconductive layer and the surface layer provided thereon. Examples of the material include the following. Metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof such as Al alloy and stainless steel. In addition, a sheet or film of synthetic resin such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, and polyamide. Conductive treatment of at least the surface on which the photoconductive layer is formed, such as glass or ceramic.

  As the conductive substrate, for example, a cylindrical shape having an outer diameter of 30 mm, 60 mm, 80 mm, 100 mm, or a sheet obtained by processing a sheet having a length of 300 mm, 450 mm, 500 mm, or the like into a belt shape can be used.

  The photoconductive layer in the present invention may be either organic or inorganic, as long as it is formed of a material having photoconductive characteristics that can satisfy the performance on electrophotographic characteristics. It is preferable to use as a component. Amorphous silicon is preferable because it has excellent hardness, and even when a surface layer is formed thereon, even when a vacuum process is used, there is little change in the layer due to degassing and the like, and the surface layer formation is not adversely affected.

  The photoconductive layer preferably contains a hydrogen atom or a halogen atom that is bonded to a dangling bond of amorphous silicon. When the photoconductive layer contains a hydrogen atom or a halogen atom, the quality, in particular, photoconductivity and charge retention characteristics are improved. The content of hydrogen atoms and halogen atoms is preferably at least 10 atomic%, particularly preferably at least 15 atomic%, more preferably at most 30 atomic%, particularly at most 25 atomic%, based on the total of silicon atoms, hydrogen atoms and halogen atoms. Preferably there is.

Moreover, it is preferable that the said photoconductive layer contains the atom which controls conductivity as needed. The atoms for controlling the conductivity may be contained in the photoconductive layer in a uniform and uniform distribution state, or may be partially contained in a distribution state that gradually changes in the layer thickness direction. . As an atom for controlling conductivity, an atom used as a so-called impurity in the semiconductor field can be used. Specifically, an atom belonging to Group 13 of the periodic table giving p-type conductivity (hereinafter abbreviated as “Group 13 atom”) or an atom belonging to Group 15 of the periodic table giving n-type conductivity (hereinafter referred to as “15th”). Abbreviated as “group atom”). The content of atoms for controlling conductivity is preferably 1 × 10 ⁻² atom ppm or more, more preferably 5 × 10 ⁻² atom ppm or more, and further preferably 1 × 10 ⁻¹ atom ppm or more with respect to silicon atoms. Further, the content of atoms for controlling conductivity is preferably 1 × 10 ⁴ atom ppm or less, more preferably 5 × 10 ³ atom ppm or less, and further preferably 1 × 10 ³ atom ppm or less.

Further, the photoconductive layer can contain carbon atoms, oxygen atoms or nitrogen atoms. The content (total amount) of carbon atoms, oxygen atoms and nitrogen atoms is 1 × 10 ⁻⁵ atom% or more, particularly 1 × 10 ⁻⁴ atoms, based on the sum of silicon atoms, carbon atoms, oxygen atoms and nitrogen atoms % ^Or more, preferably 1 × 10 ⁻³ atom% or more. The content of carbon atoms, oxygen atoms and nitrogen atoms is 10 atomic% or less, particularly 8 atomic% or less, and further 5 atomic% or less with respect to the sum of silicon atoms, carbon atoms, oxygen atoms and nitrogen atoms. It is preferable.

  The layer thickness of the photoconductive layer is, for example, preferably 15 μm or more, particularly 20 μm or more, from the viewpoint of obtaining desired electrophotographic characteristics, economy, etc., and 60 μm or less, particularly 50 μm or less, The thickness is preferably 40 μm or less. If the thickness of the photoconductive layer is 15 μm or more, an increase in the amount of current passing through the charging member can be suppressed, and deterioration can be suppressed. If the thickness of the photoconductive layer is 60 μm or less, it is possible to suppress an abnormal growth portion of amorphous silicon from being increased, for example, to suppress the horizontal direction from 50 to 150 μm and the height direction from 5 to 20 μm. it can. Thereby, the damage of the member used by rubbing the surface of the photoreceptor can be suppressed, and the formation of a defective image can be suppressed.

  Such a photoconductive layer may be formed from a single layer, or may have a multilayer structure in which the carrier generation layer and the carrier transport layer are separated.

  The photoconductive layer can be formed by forming a deposited film such as a plasma CVD method, a vacuum deposition method, a sputtering method, or an ion plating method.

Hereinafter, a method for forming a photoconductive layer using a plasma CVD method will be described in detail. Desirable source gas for supplying Si that can supply silicon atoms, source gas for supplying H that can supply hydrogen atoms, and source gas for supplying X that can supply halogen atoms in a reaction vessel that can be depressurized inside The gas state is introduced. At this time, a raw material gas capable of supplying atoms for controlling conductivity can be introduced together if necessary. Glow discharge is generated in the reaction vessel, the introduced source gas is decomposed, and silicon atoms are deposited and grown together with hydrogen atoms and other atoms on a conductive substrate previously set in place to form an amorphous silicon film. To do. As the Si supply source gas, silane gases such as silane (SiH ₄ ) and disilane (Si ₂ H ₆ ) can be preferably used. In addition to the above silanes, hydrogen (H ₂ ) gas can also be suitably used as the H supply source gas. Source gases for supplying halogen atoms include halogen compounds such as F ₂ , BrF, ClF, ClF ₃ , BrF ₃ , BrF ₅ , IF ₃ and IF ₇ , and silicon containing halogen atoms such as SiF ₄ and Si ₂ F _6. A compound gas can be mentioned as a preferable one.

The source gas for Group 13 atom supply or the source gas for Group 15 atom supply is a source material that is gaseous at normal temperature and pressure or that can be easily gasified at least under the conditions for forming a photoconductive layer. It is preferable to adopt. The group 13 atom supply source gas is specifically a compound gas such as a boron atom (B), an aluminum atom (Al), a gallium atom (Ga), an indium atom (In), or a thallium atom (Tl). In particular, a gas of a compound of B, Al, and Ga is preferable. Specific examples of the group 15 atom supply source gas include a compound gas such as a phosphorus atom (P), an arsenic atom (As), an antimony atom (Sb), and a bismuth atom (Bi). In particular, a gas of a compound of P or As is preferable. Specific examples include diborane (B ₂ H ₆ ) and phosphine (PH ₃ ).

The source gas for supplying carbon atoms, oxygen atoms, and nitrogen atoms includes methane (CH ₄ ), acetylene (C ₂ H ₂ ), carbon dioxide (CO ₂ ), O ₂ , N ₂ , and ammonia (NH ₃ ). Nitric oxide (NO) or the like can be used.

  These source gases can be diluted with hydrogen gas, helium gas or the like as necessary.

As other reaction conditions, conditions such as the gas pressure in the reaction vessel and the discharge power are appropriately selected as appropriate. For example, the gas pressure may be set to 1 × 10 ⁻² to 1 × 10 ³ Pa, preferably 5 × 10 ^{−2 to} 5 × 10 ² Pa, more preferably 1 × 10 ⁻¹ to 2 × 10 ² Pa. it can. As the discharge power, the ratio of the discharge power [W] to the flow rate [ml / min (normal)] of the gas for supplying Si can be set in the range of 0.5 to 8, preferably 2 to 6. The temperature of a base | substrate can be set, for example to 200-350 degreeC, Preferably it is 210-330 degreeC, More preferably, it is 220-300 degreeC. The above-mentioned ranges can be cited as desirable numerical ranges of the substrate temperature and gas pressure for forming these photoconductive layers. These conditions are not usually determined separately, but it is preferable to determine optimum values based on mutual and organic relevance in order to form a photoreceptor having desired characteristics.

[Surface layer]
The surface layer in the present invention contains magnesium atoms, fluorine atoms and oxygen atoms as main constituent atoms, and the main atoms satisfy the composition formula (1).

MgFxOy (1)
In the formula, x represents a number of 1.30 to 2.10, and y represents a number of 0.050 to 0.500.

  The surface layer contains magnesium atoms, fluorine atoms, and oxygen atoms as main constituent atoms in the above atomic ratio, so that even if the surface layer has a relatively large area and has a curved shape, uneven photosensitivity over the entire surface, Uniform photosensitivity with reduced residual potential unevenness. There is no absorption for short wavelengths, and for example, it has a high light transmittance for exposure light of 405 nm or the like. Moreover, the distortion with respect to external force is disperse | distributed, it has scratch resistance, and durability improves.

  The following can be considered as reasons why the photosensitivity unevenness is suppressed in the surface layer. A thin film of a compound does not always have a bonding form based on the stoichiometric composition of all the constituent atoms, and usually contains defects. Such defects cause light absorption, but this does not necessarily depend on the composition ratio. Even if the composition ratio is substantially the same, a film with many defects absorbs more light than a film with few defects. It is common that there are many.

  In order to reduce light absorption, it is important to reduce defects in the surface layer as much as possible.

  Light absorption in a layer composed of magnesium atoms and fluorine atoms or a layer composed of magnesium atoms and oxygen atoms is also expected to occur in the defect. In the surface layer satisfying the composition formula (1), an oxygen atom is taken into a defect in a bond between a magnesium atom and a fluorine atom, or a fluorine atom is taken into a defect in a bond between a magnesium atom and an oxygen atom. As a result, it is conceivable that defects in the layer composed of magnesium atoms and fluorine atoms or the layer composed of magnesium atoms and oxygen atoms are offset and light absorption is suppressed in the surface layer.

  In the surface layer, it is considered rare that fluorine atoms and oxygen atoms are substituted for each other and bonded to magnesium atoms. For this reason, it is easy to control the atomic ratio of fluorine atoms and oxygen atoms with respect to magnesium atoms in the surface layer, and a surface layer having a specific characteristic with a specific atomic ratio can be easily obtained. By changing the composition of these atoms within the range of the composition formula (1), the characteristics as the surface layer can be easily controlled, these atoms are contained in a specific ratio, and structural defects are suppressed. A film can be formed. For this reason, even on a curved large-area surface where a uniform film formation process is difficult, a film with reduced structural defects can be formed, and a uniform film with reduced photosensitivity unevenness can be obtained. It is considered a thing.

  Further, since the crystal structures of magnesium oxide and magnesium fluoride are different from the rock salt structure and the cubic rutile structure, respectively, it is considered that a certain bond structure is unlikely to appear in a film containing magnesium atoms, fluorine atoms, and oxygen atoms. For this reason, it is considered that the stress can be effectively dispersed with respect to the pressure and stress received from the outside, and the film damage can be suppressed even in an electrophotographic apparatus under severe use conditions.

The main constituent atoms contained in the surface layer satisfy the composition formula (1),
MgFxOy (1)
In the composition formula (1), x represents a number of 1.30 or more and 2.10 or less, y represents a number of 0.050 or more and 0.500 or less, but x is 1.70 or more and 2.00. The following numbers are shown, and y is preferably 0.070 or more and 0.200 or less. In the composition formula (1), when x is an atomic ratio indicating a number of 1.30 to 2.10 and y is a number of 0.050 to 0.500, uneven photosensitivity In addition to reducing residual potential unevenness, the stability to moisture is extremely high. Furthermore, in the composition formula (1), x represents a number of 1.70 or more and 2.00 or less, and y is an atomic ratio indicating a number of 0.070 or more and 0.200 or less in the composition formula (1). The above effects can be obtained more remarkably.
In the composition formula (1), x / 2 + y = 1 stoichiometrically. However, in the main constituent atoms of the surface layer, even if x and y deviate from the stoichiometric value, if 1.70 ≦ x ≦ 2.00 and 0.07 ≦ y ≦ 0.200, It is possible to reduce defects that cause unevenness in photosensitivity and unevenness in residual potential.

  The surface layer may contain other atoms such as a carbon atom, a hydrogen atom, and a nitrogen atom as long as the functions of the main constituent atoms are not impaired in addition to the main constituent atoms. The total content of these atoms in the surface layer is preferably 50 atomic% or less with respect to the content of oxygen atoms.

  The layer thickness of the surface layer may be in a range where desired electrophotographic characteristics and sufficient mechanical strength can be obtained. Specifically, the thickness is preferably 0.1 μm or more in order to suppress the occurrence of residual potential. Also, from the viewpoint of economy, it is preferably 3 μm or less, particularly preferably 1 μm or less.

  The surface layer may be formed by any method, but deposition such as glow discharge (DC or AC CVD method, etc.), sputtering method, vacuum evaporation method, ion plating method, photo CVD method, thermal CVD method, etc. It is preferred to use a film formation method. In particular, the sputtering method can be mentioned as a preferable method because the preparation of the raw materials and the film formation condition control are relatively easy and the target atomic ratio can be obtained with high accuracy.

  As a method for forming a surface layer by sputtering, magnesium metal is used as a target, and fluorine gas and oxygen gas are used as reaction gases to form a deposited film containing magnesium atoms, fluorine atoms, and oxygen atoms. Can be used. By changing the supply amount of the reaction gas, the content of fluorine atoms and oxygen atoms in the surface layer can be adjusted.

  Alternatively, magnesium oxide and magnesium fluoride may be mixed as the target so as to have the atomic composition ratio of the target photoconductive layer side region, and the deposited film may be formed using a sputtering gas. Furthermore, the atomic composition in the deposited film can be adjusted by adjusting the supply amount of the reactive gas using a reactive gas of fluorine gas and oxygen gas together with the sputtering gas.

  When adjusting the atomic composition of the deposited film to be formed by adjusting the supply amount of the reaction gas to be supplied, it is possible to adjust the atomic composition over a wide range, but it is stable for a long time, such as when forming a thick deposited film. In some cases, it is difficult to continue the discharge and the composition of the deposited film varies. This tendency is particularly seen when the supply amount of oxygen gas is large. When the atomic composition of the deposited film to be formed is adjusted by the mixing ratio of the compound used for the target, it is difficult to adjust the wide range of the atomic composition and it is necessary to use a high frequency, but stable discharge is performed for a long time. And a deposited film having a stable composition can be formed. In any case, a deposition film having a stable composition can be formed by appropriately adjusting conditions such as discharge power, pressure, and temperature. Depending on the target deposition film, the target and other conditions can be adjusted. It is preferable to select.

[Photoconductor form]
As an example of the electrophotographic photoreceptor of the present invention, one having a layer structure shown in the schematic configuration diagram of FIG. The electrophotographic photoreceptor shown in FIG. 1 comprises a conductive substrate 13 and a photoconductive layer 12 and a surface layer 11 sequentially laminated on the surface of the conductive substrate 13.

  In addition to the above, the electrophotographic photoreceptor of the present invention can be used as long as it does not impair the functions of the above layers between the conductive substrate and the photoconductive layer and between the photoconductive layer and the surface layer. You may have another layer according to the characteristic. An example thereof is a charge injection blocking layer, and these layers may have an intermediate layer whose composition is continuously changed in order to shift from the lower layer composition to the upper layer composition. .

  The charge injection blocking layer is provided between the conductive substrate and the photoconductive layer or between the photoconductive layer and the surface layer, and blocks charge injection from the conductive substrate or the surface layer to the photoconductive layer. It has a function holding function. The charge injection blocking layer is preferably formed on the basis of the material constituting the photoconductive layer. For example, the charge injection blocking layer for the photoconductive layer is based on amorphous silicon containing hydrogen atoms, halogen atoms, etc., and contains atoms that control the conductivity of group 13 elements, group 15 elements, etc. It can be prepared in the conductivity type. If necessary, the stress is adjusted by containing at least one atom selected from a carbon atom, a nitrogen atom and an oxygen atom, and the adhesion between the conductive substrate, the photoconductive layer and the surface layer is improved. Can also be planned.

[Manufacturing equipment]
An example of a CVD apparatus used for the production of the electrophotographic photoreceptor of the present invention, for example, the production of a conductive layer will be described below. The CVD apparatus shown in the schematic configuration diagram of FIG. 2 is roughly composed of a deposited film forming container 100, an exhaust device 200, and a source gas supply means 300. The source gas supply means 300 includes cylinders 301 to 305, supply valves 306 to 310, pressure regulators 311 to 315, primary valves 316 to 320, mass flow controllers 321 to 325, and secondary valves 326 to 330. The cylinders 301 to 305 are filled with a gas for a vacuum processing process, and the process gas adjusted to a pressure of, for example, about 0.2 MPa by the pressure regulators 311 to 315 through the supply valves 306 to 310 is supplied. Supply is possible.

  An exhaust device 200 is connected to the deposited film forming container 100 through an exhaust pipe 405, a throttle valve 406, and an exhaust valve 407. The exhaust device 200 includes a mechanical booster pump 201 and a rotary pump 202, and the inside of the deposited film forming container 100 is evacuated.

  The deposited film forming container includes, for example, a base plate 136 and a vacuum container 101 on a gantry 121 as shown in a vertical cross-sectional schematic configuration diagram of FIG. 3 and a horizontal cross-sectional schematic configuration diagram of FIG. A holding member 123 for holding the object to be processed 122 is provided substantially at the center in the vacuum vessel 101, and a heater 124 for heating the object to be processed 122 to a desired temperature is provided inside the holding member 123. It has been. A cap 125 is provided on the upper portion of the holding member so that the heater inside the holding member 123 is not exposed to plasma. The vacuum vessel 101 is coupled by an upper lid 126, a base plate 136, and a seal member (not shown) so that the inside can be kept airtight. A plurality of electrodes 127 are provided concentrically around the vacuum vessel 101, a matching box 423 is connected via a branch plate 128, and further connected to a high frequency introduction cable 422 and a high frequency power source 421. The vacuum vessel 101 is formed of a ceramic member such as alumina, and the high frequency power radiated from the electrode 127 is transmitted through the vacuum vessel 101 to generate glow discharge in the vacuum vessel 101. A high frequency shield 129 is provided around the electrode 127 to prevent high frequencies from leaking to the periphery. The base plate 136 is provided with exhaust ports 130 on the same circumference centered on the object 122 to be processed, and these are assembled and connected to the exhaust pipe 405. The gas introduction pipe 131 is provided outside the arrangement circle of the exhaust port 130 on the same circumference with the processing target 122 as the approximate center, and is connected to the source gas supply means 300 via the gas supply path 404. . The gas introduction pipe 131 is provided with a plurality of gas discharge holes (not shown), and supplies the source gas into the vacuum vessel 101.

  A method for preparing a photoconductive layer using such a CVD apparatus will be specifically described. The vacuum vessel 101 is fixed to a base plate 136 installed on the gantry 121 via a seal member (not shown). The conductive substrate 122 that has been degreased and cleaned is placed on the holding member 123 and the cap 125 is placed at the same time, and then the upper lid 126 is placed on the vacuum vessel 101 via a seal member (not shown).

  Next, the exhaust device 200 is moved, the valve 407 is opened, and the inside of the vacuum vessel 101 is exhausted. While viewing the display of the vacuum gauge 111, when the pressure in the vacuum vessel 101 reaches a predetermined pressure of, for example, 1 Pa or less, power is supplied to the heater 124, and the conductive substrate 122 is moved to a desired temperature of, for example, 50 ° C. to 350 ° C. Heat to temperature. At this time, an inert gas such as Ar or He can be supplied from the source gas supply means 300 to the vacuum vessel 101 and heated in an inert gas atmosphere.

  Next, a gas used for forming a deposited film is supplied from the source gas supply means 300 to the vacuum vessel 101. If necessary, the supply valves 306 to 310, the primary valves 316 to 320, and the secondary valves 326 to 330 are opened, and flow rates are set in the mass flow controllers 321 to 325. When the flow rate of each mass flow controller is stabilized, the throttle valve 406 is operated while viewing the display of the pressure gauge 111 to adjust the pressure in the vacuum vessel 101 to a desired pressure. When the pressure is stabilized, high frequency power is applied from the high frequency power source 421 and simultaneously the matching box 423 is operated to generate plasma discharge in the vacuum vessel 101. Thereafter, the high frequency power is quickly adjusted to a desired power, and a deposited film is formed. After the deposited film is formed, the application of the high frequency power is stopped, the supply of the raw material gas is stopped, the throttle valve 406 is opened, and the inside of the vacuum vessel 101 is exhausted to a pressure of 1 Pa or less.

  The formation of the deposited film is completed as described above. For example, when a plurality of deposited films such as the lower charge injection blocking layer and the photoconductive layer are formed, the above operation is repeated to form each layer. In the case of having an intermediate layer, it is also possible to change the raw material gas flow rate, pressure, etc. over a certain period of time to shift to the upper layer deposition conditions. After all the deposited films are formed, a leak valve (not shown) is opened, and the inside of the vacuum vessel 101 is set to atmospheric pressure, and the conductive substrate 122 is taken out.

  Next, an example of a sputtering apparatus used for the production of the electrophotographic photoreceptor of the present invention, for example, the production of the surface layer will be described below. The sputtering apparatus shown in the schematic configuration diagram of FIG. 5 mainly includes a reaction furnace 5100 and a charging furnace 5200.

  The reaction furnace 5100 includes a reaction vessel 5108, a workpiece 122, for example, a holder 5113 that supports a conductive substrate on which a photoconductive layer is formed, a reaction gas nozzle 5103, a rotating shaft 5104, a sputter gas introduction tube 5105, a cathode 5102, and a target 5106. Is provided. The reaction vessel is connected to an exhaust device (not shown) via a valve 5117. The holder is rotatably supported by a rotary shaft seal 5119, and is installed on a rotary shaft 5104 connected to a motor 5118 in the atmosphere. A heater 5114 wound around the rotary shaft 5104 is provided inside, and a workpiece is processed. 122 can be heated to a desired temperature. The object 122 is rotated by a motor 5118 during the formation of the deposited film, so that a uniform deposited film is formed over the entire circumference.

The reactive gas nozzle 5103 includes a gas discharge hole 5116 and is connected to a raw material gas supply means (not shown) via a valve 5115 so that a reactive gas such as F ₂ or O ₂ is supplied from the reactive gas nozzle 5103. It has become. As the source gas supply means, the same source gas supply means 300 as that provided in the CVD apparatus shown in FIG. 2 can be used. The cathode 5102 is supported by the reaction vessel 5108 through an insulating member 5107 and is surrounded by a shield 5111 that is isolated from plasma. The cathode 5102 is provided with cooling water pipes 5131 and 5132 so that the cooling water is circulated and cooled during the sputtering process. Further, the cathode 5102 is connected to a power source 5109 outside the reaction vessel 5108, and for example, a DC power source, a power source having a function of periodically inverting the applied polarity, a high-frequency power source, or the like is applied.

  A sputtering gas introduction pipe 5105 is installed in the vicinity of the cathode 5102 and connected to a sputtering gas supply means (not shown) via a valve 5110, and a sputtering gas such as argon (Ar) is introduced into the discharge region. It is like that.

  A pair of permanent magnets 5129 is formed on the target 5106 so as to form a magnetic field parallel to the target, and is arranged so as to correspond to the length of the object to be processed 122, and in the generatrix direction of the object to be processed 122 by magnetron sputtering. A uniform deposited film is formed.

  The charging furnace 5200 includes a vacuum container 5201, an actuator 5203 for transporting an object to be processed, and a door 5202. The vacuum vessel 5201 is formed with a vacuum separately from the reaction vessel 5108 by an exhaust device connected via a valve 5205, and the vacuum can be released by introducing air via the valve 5204. The reaction vessel 5108 communicates with the valve 5101.

  The actuator 5203 is supported by the vacuum vessel 5201 with the shaft 5207 supported by the vacuum seal 5206. A chucking mechanism 5208 for holding the object to be processed 122 is provided at the tip of the shaft 5207, and the shaft 5207 is expanded and contracted by an actuator so that the object 122 is carried in and out between the charging furnace and the reaction furnace. Yes.

  A method for preparing the surface layer using such a sputtering apparatus will be specifically described. The valve 5117 is opened, and the inside of the reaction vessel 5108 is exhausted by the exhaust device. On the other hand, the workpiece 122 on which the photoconductive layer is formed is put into the charging furnace 5200 through the door 5202, set in the chucking mechanism 5208, the door 5202 is closed, the valve 5205 is opened, and the inside of the charging furnace 5200 is exhausted. When the inside of the reaction vessel 5108 and the charging furnace 5200 reaches a vacuum degree of 0.1 Pa or less, for example, the valve 5101 is opened, the shaft 5207 is extended by driving the actuator 5203, and the workpiece 122 is held in the holder 5113 in the reaction vessel 5108. Install in. Thereafter, the shaft is shortened by driving the actuator, the chucking mechanism is moved back to the charging furnace, and the gate valve 5101 is closed.

  If necessary, the heater 5114 is energized to heat the workpiece 122. When the object to be processed reaches a desired temperature, the sputtering gas and the reactive gas are introduced into the reaction vessel 5108 by opening the valves 5110 and 5115, respectively. When the inside of the reaction vessel 5108 reaches a predetermined pressure, electric power is supplied to the cathode 5102. Apply to cause glow discharge. A target is sputtered to form a deposited film uniformly in the direction of the generatrix of the object to be processed. At this time, the rotating shaft 5104 is rotated by the motor 5118 to rotate the object to be processed, so that the deposited film is uniformly formed in the circumferential direction. When the desired deposited film is formed, the supply of power from the power source 5109 is stopped and the formation of the deposited film is completed.

  In order to form a surface layer composed of a plurality of regions, conditions such as desired gas, pressure, and substrate temperature are set, and then power is applied again to the cathode 5102 to cause glow discharge. At the same time, the valves 5110 and 5115 are closed, and the supply of the reactive gas and the sputtering gas is finished. At the same time, the heater 5114 is turned off, and the reaction vessel 5108 is once evacuated to a pressure of 0.1 Pa or less, for example. open. After the actuator 5203 is driven to extend the shaft 5207 and the workpiece 122 is held by the chucking mechanism 5208, the shaft 5207 is shortened, the workpiece 122 is carried into the charging furnace 5200, and the gate valve 5101 is closed. The valve 5204 is opened, the inside of the vacuum vessel 5201 is vented, the door 5202 is opened, the object 122 is taken out, and a photoconductor is obtained.

  The CVD apparatus shown in FIGS. 2 to 4 and the sputtering apparatus shown in FIG. 5 can be connected by an airtight conveying means, and the photoconductive layer and the surface layer can be formed while maintaining a vacuum state.

[Examples 1 to 3, Comparative Example 1]
The conditions shown in Table 1 using a conductive substrate obtained by mirror-finishing the surface of an aluminum cylinder having a diameter of 80 mm, a length of 358 mm, and a thickness of 3 mm as the conductive substrate, and using the CVD apparatus shown in FIGS. Thus, a photoconductive layer was formed. The power supply used a frequency of 13.56 MHz.

After forming the photoconductive layer, the surface layer was formed using the sputtering apparatus shown in FIG. Magnesium metal was used as the target. O ₂ and F ₂ are used as reactive gases, Ar is used as a sputtering gas, y in the composition formula (1) is set to a substantially constant value, and the value of x is changed. Under the conditions shown in Tables 2 and 3, magnesium is used. A surface layer composed of atoms, oxygen atoms and fluorine atoms was formed to obtain photoreceptors 1 to 4.

  The fluorine gas flow rate shown in Table 3 is the flow rate of the fluorine gas before being diluted with Ar, and was actually introduced together with 9 times the amount of fluorine gas.

  As for x and y shown in Table 3, a sample obtained by cutting a photoreceptor formed under the same conditions into a size of about 12 mm × 12 mm was prepared, and the composition of the surface layer was measured. ESCA (PHI Quantum 2000 Scanning ESCA) was used as a measuring apparatus, and the range of 2 mm × 2 mm was sputtered at 4 kV for 5 minutes to remove the influence of surface deposits, and the values of x and y in MgFxOy were measured.

  Using the following electrophotographic apparatus, the obtained photoreceptor was evaluated for charging performance, charging performance unevenness, photosensitivity, photosensitivity unevenness, residual potential, residual potential unevenness, scratches, and spots. The results are shown in Table 4.

  The cleaning roller of the digital copying machine (iR6000: manufactured by Canon Inc.) was changed from a magnet roller to a urethane rubber sponge roller. The sponge roller was in contact with the photoconductor with a nip width of 5 mm, and a remodeled machine (hereinafter referred to as a remodeled machine) that was remodeled so as to rotate in the forward direction with a circumferential speed difference of 120% with respect to the photoconductor rotation was used. . The transmission wavelength of the image exposure laser was 405 nm.

[Charging ability, uneven charging ability]
A photoconductor was installed in this modified machine, image exposure (laser) was performed, and a high voltage of +6 kV was applied to the charger to perform corona charging. The surface potential (that is, the dark portion charging potential) generated on the photosensitive member at this time was measured by installing a sensor of a surface potential meter (Model 334 manufactured by TREK) at a position corresponding to the developing unit. The same measurement was performed at 20 arbitrary points on the photoconductor, and among the obtained values, the lowest potential value was evaluated as the charging ability. Moreover, the ratio of the minimum value with respect to the maximum value among the obtained measured values was evaluated as uneven charging ability. The larger the value, the greater the uneven charging performance.

[Light sensitivity, uneven light sensitivity]
A photoconductor was installed in the modified machine, and the charging current applied to the charger was adjusted so that the dark portion charging potential at the developing device position was 450V. While maintaining this charging current, image exposure light (laser) was irradiated, and the intensity of the image exposure light was adjusted so that the bright portion surface potential at the developing unit position was 50V. The image exposure light intensity at this time was fixed, and the potential when this was irradiated to other parts of the photoreceptor was measured at 20 arbitrary points on the photoreceptor. Of the obtained measured values, the value having the worst characteristic, that is, the value of the maximum potential was taken as the photosensitivity, and the ratio of the minimum value to the maximum value among the obtained measured values was taken as the photosensitivity unevenness. The larger the value is, the larger the non-uniformity of light sensitivity is.

[Residual potential, residual potential unevenness]
Similar to the photosensitivity measurement, after adjusting the surface potential of the dark area at the position of the developing unit of the photoconductor to 450 V, the surface of the bright area was irradiated with a laser of strong exposure (for example, 1.2 μJ / cm ² ). The potential was measured. The same measurement was performed at 20 arbitrary points on the photosensitive member, and the value having the lowest characteristic, that is, the value having the highest potential was evaluated as the residual potential. Further, the ratio of the minimum value to the maximum value among the obtained measured values was evaluated as the residual potential unevenness. The larger the value, the greater the residual potential unevenness.

After the above evaluation, a test chart consisting of 6-point hiragana characters was placed on the platen, and a durability test was repeated to form an image of 500,000 sheets of A4 copy paper in an environment of an air temperature of 30 ° C. and a humidity of 80% RH. It was. At this time, high-quality paper weighing 64 g / m ² and high-quality paper weighing 80 g / m ² were used as copy paper, and images were formed using a sequence in which 10 sheets were alternately fed.

[Scratches]
After performing the above durability test, a halftone image is output in the same environment as the durability test, the image defect of the scratch appearing on the image, and the presence or absence of the scratch in the image forming range of the photoreceptor surface taken out from the electrophotographic apparatus Were visually examined and evaluated according to the following criteria.
A: No scratches are observed on the surface of the electrophotographic photoreceptor.
○: Scratches are seen on the surface of the electrophotographic photoreceptor, but do not appear on the image.
Δ: Scratches appear on the image, but are fine and slight, and there is no practical problem.
X: Scratches appear on the image and there is a possibility of misreading of characters, etc., which is not practical.

[Stain]
After immersing the photoreceptor in isopropyl alcohol (IPA) and cleaning the surface for 5 minutes by ultrasonic cleaning, the IPA adhering to the surface is blown off with nitrogen blow, and using a dryer set at 110 ° C. for 1 hour or more Dried. After the temperature of the photoconductor reaches 25 ° C., about 0.003 to 0.010 ml of purified water (Kyoei Pharmaceutical Co., Ltd., Japanese Pharmacopoeia purified water) is dripped in the surface image formation region, and 30 seconds have elapsed. The water droplets were wiped off. While visually observing the presence or absence of spots on the surface after wiping off the water droplets, this photoconductor is installed in the above-mentioned remodeling machine, and a halftone image is output under the same conditions as in the above-mentioned durability test. The presence or absence of appearing spots was visually observed and evaluated according to the following criteria. For the evaluation of the stain, another photoconductor was formed with the same formulation as the photoconductor subjected to other evaluations, and only the stain was evaluated.
A: No spots are observed on the surface of the electrophotographic photoreceptor.
○: Spots are seen on the surface of the electrophotographic photoreceptor, but do not appear on the image.
Δ: Spots appear on the image, but they are fine and slight, and there is no practical problem.
X: Spots appear remarkably on the image, and there is a possibility of misreading of characters, etc., which is not practical.

  In the table, the values of charging ability, uneven charging ability, photosensitivity, and residual potential are shown by relative comparison with these values of the photosensitive member 4 being 1.00.

  In these evaluations, if the charging ability is 0.90 or more, it can be said that the photosensitive member has good characteristics. When the charging ability unevenness is 3.70 or less, an image having no practical problem can be obtained, and when it is 2.50 or less, good characteristics with slight unevenness in density are obtained. On the other hand, if it is 1.20 or less, it is possible to obtain good characteristics with substantially no density unevenness on the image.

  With respect to the photosensitivity, there is no practical problem when it is 1.20 or less, and when it is 1.10 or less, good characteristics that can be applied to a wide range of process conditions can be obtained. The result of unevenness in light sensitivity is shown in FIG. In FIG. 6, each value of the photosensitivity unevenness is shown by relative comparison with the value of the photoconductor 4 being 1.00. With respect to unevenness in light sensitivity, an image having no practical problem can be obtained when it is 3.70 or less, and good characteristics with slight unevenness of density can be obtained when it is 2.50 or less. On the other hand, if it is 1.20 or less, it is possible to obtain good characteristics with substantially no density unevenness on the image.

  As for the residual potential, if it is 3.00 or less, it is possible to obtain good characteristics applicable to a wide range of process conditions. The results of the residual potential unevenness are shown in FIG. In FIG. 7, each value of the residual potential unevenness is shown by relative comparison with the value of the photoconductor 4 being 1.00. Although the residual potential unevenness does not directly affect the image characteristics, in many cases, it affects the chargeability unevenness. Therefore, as with the chargeability unevenness, there is no practical problem at 3.70 or less, and 2.50 or less. It is preferable that 1.20 or less is more preferable.

  From the results, it was revealed that the photosensitivity unevenness and the change appear in the scratch depending on the F content. According to FIG. 6, the unevenness of the photosensitivity is 2.50 or less, the F content is 1.30 or more, and the unevenness of the photosensitivity is about 1.20 or less, the F content is about It can be determined that the range is 1.70 or more. There was no obvious change in characteristics other than the photosensitivity unevenness and scratches.

[Examples 4 to 6, Comparative Example 2]
Photoconductive layers were prepared in the same manner as in Example 1, and surface layers were formed in the same manner as in Example 1 except that the conditions shown in Tables 5 and 6 were used. In Examples 4 to 6 and Comparative Example 2, the fluorine gas flow rate was changed so that y in the composition formula (1) of the surface layer became almost constant and x changed.

  The fluorine gas flow rate shown in Table 6 is the flow rate of the fluorine gas alone before being diluted with Ar, and was actually introduced together with Ar four times the fluorine gas amount.

  For the obtained photoreceptor, the values of x and y in the composition formula (1) of the surface layer and the characteristics of the photoreceptor were evaluated in the same manner as in Example 1. The results are shown in Table 7. The results of the photosensitivity unevenness are shown in FIG. 8, and the residual potential unevenness is shown in FIG.

In Table 7, charging ability, charging unevenness, photosensitivity, photosensitivity unevenness, residual potential, and residual potential unevenness are shown as relative values with these values of the photoconductor 4 being 1.00.

From the results, it became clear that changes appear in the charging performance unevenness, scratches, photosensitivity unevenness and residual potential unevenness depending on the F content. Here, since the charging performance unevenness and the photosensitivity unevenness change in the same manner as the residual potential unevenness, it is considered that the charging performance unevenness and the photosensitivity unevenness are affected by the residual potential unevenness. . The F content in which the residual potential unevenness is 2.50 or less is a preferable range in which the concentration unevenness is slight, and the F content in which the residual potential unevenness is 1.20 or less is 2.00 or less. The range is more desirable, and it can be determined that the density unevenness does not substantially occur. No significant changes were observed in the characteristics other than the charging ability unevenness, the photosensitivity unevenness, the residual potential unevenness, and the scratches.
[Examples 7 to 9, Comparative Examples 3 and 4]

  Photoconductive layers were prepared in the same manner as in Example 1, and surface layers were formed in the same manner as in Example 1 except that the conditions shown in Tables 8 and 9 were used. Photoconductors 9 to 13 were prepared. In Examples 7 to 9 and Comparative Examples 3 and 4, the oxygen gas flow rate was changed so that x in the composition formula (1) of the surface layer became substantially constant and y changed.

  The fluorine gas flow rate shown in Table 9 is the flow rate of the fluorine gas alone before being diluted with Ar, and was actually introduced together with 5 times the amount of fluorine gas.

  For the obtained photoreceptor, the values of x and y in the composition formula (1) of the surface layer and the characteristics of the photoreceptor were evaluated in the same manner as in Example 1. The results are shown in Table 10. FIG. 10 shows the results of the photosensitivity unevenness, and FIG. 11 shows the residual potential unevenness. In the photoreceptor 9, the fluorine atom content was detected as an impurity, and y = 0.

In Table 10, charging ability, charging unevenness, photosensitivity, photosensitivity unevenness, residual potential, and residual potential unevenness are shown as relative values with these values of the photoconductor 4 being 1.00.

  From the results, it became clear that changes appear in the scratches and unevenness of photosensitivity depending on the O content. It can be seen that the residual potential unevenness decreases rapidly when the O content exceeds 0.047. This indicates that the effect of offsetting the defects of Mg and F and Mg and O is not necessarily sufficient unless the O content exceeds a certain level. A range where the O content is 0.050 or more where the residual potential unevenness is 2.50 or less is a preferable range in which the concentration unevenness is slight, and an F content where the residual potential unevenness is 1.20 or less is 0.070. The above range is more preferable, and it can be determined that the density unevenness does not substantially occur. There were no significant changes in properties other than scratches and unevenness in light sensitivity.

[Examples 10 to 13]
Photoconductive layers were prepared in the same manner as in Example 1, and surface layers were formed in the same manner as in Example 1 except that the conditions shown in Tables 11 and 12 were used. Photoconductors 14 to 17 were prepared. In Examples 10 to 13, the oxygen gas flow rate was changed so that x in the composition formula (1) of the surface layer became substantially constant and y changed.

  The fluorine gas flow rate shown in Table 12 is the flow rate of the fluorine gas before dilution with Ar, and was actually introduced together with 9 times the amount of fluorine gas.

  For the obtained photoreceptor, the values of x and y in the composition formula (1) of the surface layer and the characteristics of the photoreceptor were evaluated in the same manner as in Example 1. The results are shown in Table 13. FIG. 12 shows the results of the photosensitivity unevenness, and FIG. 13 shows the residual potential unevenness.

In Table 13, charging ability, charging unevenness, photosensitivity, photosensitivity unevenness, residual potential, and residual potential unevenness are shown as relative values with these values of the photoconductor 4 being 1.00.

  From the results, it becomes clear that there is a tendency for spots to occur as the O content increases, and it can be determined that the boundary of the oxygen content with respect to the presence or absence of spots is about 0.200. However, the spots of Examples 12 and 13 were all slight and could not be recognized on the image at all. In addition, no significant change was observed for other characteristics.

[Examples 14 to 16, Comparative Example 5]
Photoconductive layers were prepared in the same manner as in Example 1, and surface layers were formed in the same manner as in Example 1 except that the conditions shown in Tables 14 and 15 were used. Photoconductors 18 to 21 were prepared. In Examples 14 to 16 and Comparative Example 5, the oxygen gas flow rate was changed so that x in the composition formula (1) of the surface layer became substantially constant and y changed.

  The flow rate of the fluorine gas shown in Table 16 is the flow rate of the fluorine gas alone before being diluted with Ar, and was actually introduced together with 4 times the amount of fluorine gas.

  For the obtained photoreceptor, the values of x and y in the composition formula (1) of the surface layer and the characteristics of the photoreceptor were evaluated in the same manner as in Example 1. The results are shown in Table 16. FIG. 14 shows the results of the photosensitivity unevenness, and FIG. 15 shows the residual potential unevenness.

In Table 16, charging ability, charging unevenness, photosensitivity, photosensitivity unevenness, residual potential, and residual potential unevenness are shown as relative values with these values of the photoconductor 4 being 1.00.

  From the results, it was revealed that the photosensitivity unevenness and the stain appear depending on the O content. Further, it can be determined that the boundary of the O content with respect to the region where the unevenness of the photosensitivity is 1.20 or less and the region where the spot is ○ is about 0.500 or less. That is, it has been found that by containing F, MgO characteristics strongly appear and spots are generated from an O content less than 1: 1, which is the stoichiometric composition of MgO. Further, the photosensitivity was slightly deteriorated as the O content was increased, but both were within the range of good characteristics. There was no significant change in characteristics other than light sensitivity unevenness, spots, and light sensitivity.

[Examples 17 and 18]
In the same manner as in Example 1, a photoconductive layer was prepared, and fluorine gas and oxygen gas were not used. Instead of magnesium metal as a reaction gas target, the ratio of MgF ₂ and MgO was changed as shown in Table 18. The conditions shown in Table 17 were used. Other than that was carried out similarly to Example 1, the surface layer was formed, and the photoreceptors 22 and 23 were prepared.

  The magnesium fluoride ratio and the magnesium oxide ratio shown in Table 18 indicate mol% in the entire target.

  For the obtained photoreceptor, the values of x and y in the composition formula (1) of the surface layer and the characteristics of the photoreceptor were evaluated in the same manner as in Example 1. The results are shown in Table 19. The results of the photosensitivity unevenness are shown in FIG. 16, and the residual potential unevenness is shown in FIG.

In Table 19, charging ability, charging unevenness, photosensitivity, photosensitivity unevenness, residual potential, and residual potential unevenness are shown as relative values with these values of the photoconductor 4 being 1.00.

The results show that even when using MgF _2, MgO as a sputtering target, the photosensitive member was obtained with excellent properties.

It is a schematic block diagram which shows an example of the electrophotographic photoreceptor of this invention. It is a figure which shows schematic structure figure of the CVD apparatus used for manufacture of the electrophotographic photoreceptor of this invention. It is a figure which shows the schematic block diagram in the vertical direction of the CVD apparatus shown in FIG. It is a figure which shows the schematic block diagram in the cross direction of the CVD apparatus shown in FIG. It is a figure which shows schematic structure figure of the sputtering device used for manufacture of the electrophotographic photoreceptor of this invention. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. It is a figure which shows the residual electric potential nonuniformity of an example of the electrophotographic photoreceptor of this invention shown in FIG. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. It is a figure which shows the residual electric potential nonuniformity of an example of the electrophotographic photoreceptor of this invention shown in FIG. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. It is a figure which shows the residual electric potential nonuniformity of an example of the electrophotographic photoreceptor of this invention shown in FIG. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. It is a figure which shows the residual electric potential nonuniformity of an example of the electrophotographic photoreceptor of this invention shown in FIG. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. It is a figure which shows the residual electric potential nonuniformity of an example of the electrophotographic photoreceptor of this invention shown in FIG. It is a figure which shows the photosensitivity unevenness of an example of the electrophotographic photoreceptor of this invention. FIG. 17 is a diagram showing unevenness in residual potential of an example of the electrophotographic photoreceptor of the present invention shown in FIG. 16.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrophotographic photoreceptor 11 Surface layer 12 Photoconductive layer

Claims (3)

In an electrophotographic photoreceptor having at least a photoconductive layer and a surface layer on a conductive substrate,
The surface layer contains magnesium atoms, fluorine atoms and oxygen atoms as main constituent atoms, and the main constituent atoms are represented by the composition formula (1)
MgF _x O _y (1)
(Wherein x represents a number of 1.30 or more and 2.10 or less, y represents a number of 0.050 or more and 0.500 or less).   2. The electrophotography according to claim 1, wherein in the composition formula (1), x represents a number of 1.70 or more and 2.00 or less, and y represents a number of 0.070 or more and 0.200 or less. Photoconductor.   3. The electrophotographic photoreceptor according to claim 1, wherein the photoconductive layer contains amorphous silicon as a main component.

Images