JP5645554B2 - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor and an image forming apparatus.

  After the surface of an image carrier such as an electrophotographic photosensitive member is charged by a charging roll as a charging means, the surface of the photosensitive drum is subjected to image exposure to form an electrostatic latent image, and the electrostatic latent image is developed. 2. Description of the Related Art Conventionally, an image forming method called a Carlson process, in which a toner image is formed by an apparatus and a toner image is formed and an image is formed by transferring and fixing the toner image on a transfer material, has been widely used.

  When an image is formed by using an image forming apparatus such as a copying machine or a printer using the Carlson process, an image defect called a so-called white spot phenomenon may occur in the formed image. The white spot phenomenon is caused by, for example, a micro image defect having a size of about φ0.5 to 2.5 mm in which toner particles are not attached, such as in a black pattern image. It is a phenomenon.

  For example, the following Patent Document 1 describes a technique for suppressing the occurrence of white spots by adjusting the AC voltage applied by the charging means.

Japanese Patent Application Laid-Open No. 2006-267939

  In recent years, there has been a demand for higher resolution and higher accuracy of the formed image, and there has been a demand for sufficiently suppressing the white spot phenomenon. However, as described in Patent Document 1, even when the voltage applied to the electrophotographic photoreceptor by the charging means is controlled, the white spot phenomenon cannot be sufficiently suppressed in many cases. This is presumably because the main factor of the white spot phenomenon exists in addition to the charged state of the electrophotographic photoreceptor. Conventionally, the main factors other than the charged state have not been sufficiently elucidated, and the white spot phenomenon has not been sufficiently suppressed.

  The present invention has been made to solve such problems.

  In order to solve the above problems, a conductive substrate, a photoconductive layer containing amorphous silicon formed on the conductive substrate, a coating layer containing amorphous silicon carbide formed on the photoconductive layer, and An electrophotographic photoreceptor comprising a polyolefin resin attached to a surface of a coating layer is provided.

  A step of forming a photoconductive layer containing amorphous silicon on the surface of the conductive substrate; a step of forming a coating layer containing amorphous silicon carbide on the photoconductive layer; and The present invention also provides a method for producing a photoreceptor for electrophotography, comprising a step of bombarding and a step of attaching a polyolefin resin to the surface of the multi-layer after the ion bombardment.

Further, the electrophotographic photosensitive member described above, a charging means for charging the surface of the electrophotographic photosensitive member with static electricity, and exposing the electrostatically charged electrophotographic photosensitive member to exposure light, the electrophotographic photosensitive member. Exposure means for forming an electrostatic latent image on the surface of the photosensitive member; toner is supplied to the surface of the electrophotographic photosensitive member on which the electrostatic latent image is formed; and a toner image corresponding to the latent image is transferred to the electronic image A developing unit formed on the surface of the photographic photosensitive member; a transfer unit that transfers the toner image onto a transfer material; and a cleaning unit that removes the toner remaining on the surface of the electrophotographic photosensitive member after the transfer. An image forming apparatus including the image forming apparatus is also provided.

  According to the electrophotographic photoreceptor and the image forming apparatus of the present invention, it is possible to suppress the occurrence of the white spot phenomenon.

FIG. 3 is a perspective view illustrating a basic configuration of the electrophotographic photosensitive member of the present invention and showing a state where an insertion portion is notched. FIG. 2 is a schematic top view schematically showing a surface state of the electrophotographic photosensitive member shown in FIG. 1. 1 is a schematic sectional side view of an embodiment of a plasma CVD apparatus used for producing an electrophotographic photoreceptor of the present invention. FIG. 4 is a schematic top sectional view of the plasma CVD apparatus shown in FIG. 3. It is an example of the voltage applied when producing the electrophotographic photoreceptor shown in FIG. It is an example of the voltage applied when producing the electrophotographic photoreceptor shown in FIG. 1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. FIG. 8 is a partially enlarged view of a developing device provided in the image forming apparatus provided in FIG. 7. The measured values of surface free energy and the values of surface work and hydrogen bond energy before mounting the image forming apparatus are shown for a plurality of electrophotographic photoreceptors including the electrophotographic photoreceptor of one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view for explaining the basic configuration of the electrophotographic photoreceptor 1 (hereinafter referred to as the photoreceptor 1) of the first embodiment, and shows a state where a part of the photoreceptor 1 is cut away. Show. FIG. 2 is a schematic top view schematically showing the surface state of the photoreceptor 1.

  In this figure, a conductive substrate 10 made of aluminum or the like is provided as a substrate. A plurality of layers made of an amorphous material are stacked on the conductive substrate 10. In the present embodiment, a charge injection blocking layer 12 made of amorphous silicon or the like is formed on the surface of the conductive substrate 10. A photoconductive layer 14 made of amorphous silicon or the like is provided on the charge injection blocking layer 12.

  On the photoconductive layer 14, an intermediate layer 16 made of SiC: H containing amorphous silicon, carbon atoms, and hydrogen atoms is provided.

  Although it does not restrict | limit especially as a constituent material of the electroconductive base | substrate 10, Metal materials, such as Al, SUS, Zn, Cu, Fe, Ti, Ni, Cr, Ta, Sn, Au, Ag, and those alloys It is preferable to make it from a material.

  Moreover, the material which carried out the electroconductive process by vapor-depositing transparent conductive materials, such as the metal mentioned above, ITO, and SnO2, on the surface of electrical insulators, such as resin, glass, and ceramics, can also be used. The use of an Al alloy is preferable in that the cost is reduced, the weight can be reduced, and the adhesion with a photoconductive layer or charge injection blocking layer, which will be described later, is improved and the reliability is improved.

  The charge injection blocking layer 12 is preferably provided between the conductive substrate 10 and the photoconductive layer 14 as necessary, and is preferably provided to block charge injection from the conductive substrate 10. That is, the charge injection blocking layer 12 controls the flow of charges in a predetermined direction, and more precisely controls the lateral flow of electrons in the coating layer 18, whereby the photoconductor 1 with further excellent resolution can be obtained. .

  The charge injection blocking layer is formed of an amorphous silicon-based material such as amorphous silicon (a-Si) as described above (hereinafter sometimes referred to as a-Si-based material). It is preferable to use an amorphous silicon material of an alloy to which C, N, O or the like is added. By doing so, it is possible to stably obtain electrophotographic characteristics excellent in high photoconductivity characteristics, high-speed response characteristics, repeat stability, heat resistance, durability, etc., and further with the coating layer formed of an amorphous silicon-based material. Excellent consistency.

  Here, as an a-Si material of an alloy obtained by adding C, N, O, etc. to a-Si, a-SiC, a-SiN, a-SiO, a-SiGe, a-SiCN, a-SiNO , A-SiCO and a-SiCNO. The photoconductive film made of these a-Si materials is formed by, for example, a glow discharge decomposition method, various sputtering methods, various vapor deposition methods, an ECR method, a photo CVD method, a catalytic CVD method, and a reactive vapor deposition method. In forming the film, hydrogen (H) or a halogen element (F or Cl) is used for terminating the dangling bond in a range of 1 to 40 atomic% when the entire film is 100 atomic%. can do.

  Further, in the formation of the photoconductive film, in order to obtain desired characteristics of the electrical characteristics such as the dark conductivity and photoconductivity of each layer and the optical band gap, a group 13 element of the periodic table (hereinafter, Or a group 15 element of the periodic table (hereinafter abbreviated as “Group 15 element”), or the content of an element such as C, N, or O is adjusted. Thus, the various characteristics described above can be adjusted. In addition, as the Group 13 element and the Group 15 element, boron (B) and phosphorus (P) are used in that the semiconductor characteristics can be changed sensitively with excellent covalent bonding, and the excellent photosensitivity can be obtained. It is desirable to use it. When the group 13 element and the group 15 element are contained together with elements such as C and O, the content of the group 13 element is 0.1 to 20000 ppm, and the content of the group 15 element is 0.1 to 10,000. Preference is given to ppm.

  When elements such as C and O are not contained or contained in a small amount, the content of the group 13 element is 0.01 to 200 ppm, and the content of the group 15 element is 0.01 to 100 ppm. Preferably there is. Further, these elements may be provided with a gradient in the layer thickness direction, and in this case, the average content of the entire layer may be within the above range.

  Although the above-described a-Si-based materials have the same range of constituent elements and constituent ratios in the photoconductive layer described later, the charge injection blocking layer has more Group 13 elements than the photoconductive layer. In addition, the conductivity may be adjusted by adding a Group 15 element or a higher resistance by adding more C, N, or O.

  The thickness of the charge injection blocking layer is set to a value in the range of 0.5 to 12 μm. If the film thickness of the electrification injection blocking layer is within this range, it can be formed relatively easily with a uniform thickness, and a sufficient charge injection blocking effect for the conductive substrate can be exhibited.

As shown in FIG. 1, the photoconductive layer (first layer) 14 is mainly composed of an amorphous silicon-based material and is made of a photoconductive material. Therefore, it is preferable to contain at least one element selected from the group consisting of, for example, a hydrogen atom and a halogen atom in addition to the amorphous silicon-based material. That is, by adding such atoms, the charge mobility in the photoconductive layer can be accurately controlled within a predetermined range.

  In addition, as in the case of the charge injection blocking layer described above, an a-Si based material of an alloy obtained by adding C, N, O or the like to a-Si, if necessary, or a group 13 element or a group 15 element is contained. Thus, electrical characteristics such as conductivity and photoconductivity and optical band gap can be adjusted.

  Further, for the photoconductive layer, microcrystalline silicon (μc-Si) may be included in the a-Si-based material, and when this μc-Si is included, dark conductivity and photoconductivity are increased. Therefore, there is an advantage that the degree of freedom in designing the photoconductive layer is increased. Such μc-Si can be formed by adopting the film formation method described above and changing the film formation conditions.

  For example, in the glow discharge decomposition method, it can be formed by setting the temperature and high-frequency power of the conductive substrate to be higher and increasing the flow rate of hydrogen as a dilution gas. Further, an impurity element similar to that described above may be added to the photoconductive layer containing μc-Si.

  The film thickness of the photoconductive layer is set to a value in the range of 1 to 100 μm, for example. By setting the film thickness of the photoconductive layer within this range, it can be relatively easily formed to have a uniform thickness, and sufficient photoconductivity can be exhibited. In this respect, the thickness of the photoconductive layer is more preferably set to a value in the range of 5 to 50 μm, and further preferably set to a value in the range of 8 to 20 μm.

  Moreover, it is preferable that an intermediate | middle layer contains a-SiC: H containing an amorphous silicon type material, a carbon atom, and a hydrogen atom. The reason for this is that an a-Si photosensitive member having such an intermediate layer is excellent in resolution due to a synergistic effect with a coating layer to be described later, and has little image flow even when a heaterless system is employed. It is because it can be obtained.

  In configuring the intermediate layer, the constituent material may contain a group 13 element or a group 15 for adjusting electrical characteristics.

  In addition to the amorphous silicon (a-Si), various materials can be used for the intermediate layer. For example, as an a-Si-based material, amorphous silicon nitride (a-SiN), amorphous silicon oxide (a-SiO), amorphous silicon oxycarbide (a-SiCO), amorphous silicon oxynitride (a-SiNO), etc. A high resistance material may be used. These are formed by the same thin film forming means as a-Si. In forming the film, hydrogen or halogen (F, Cl) is used in the film for dangling bond termination or for adjusting the hardness or resistance value. It is preferable to contain 1 to 160 atomic% with respect to the total number of silicon atoms and carbon atoms.

  A covering layer 18 containing amorphous silicon, carbon atoms, and hydrogen atoms is provided on the intermediate layer 16. A resin structure 19 made of a polyolefin resin is attached to the surface of the coating layer 18. In the present embodiment, the resin structure 19 is dispersed and attached to the entire surface of the coating layer 18. The coating layer 18 has a thickness in the range of 1000 to 1500 mm, for example. The covering layer 18 is composed mainly of a-SiC: H containing an amorphous silicon-based material, carbon atoms, and hydrogen atoms.

In the present embodiment, the polyolefin resin is, for example, a polystyrene resin. Polyolefin resins such as polypropylene and polystyrene are also contained in toner particles in image forming apparatuses, for example. The polyolefin resin contained in the toner particles is contained as a wax component that improves the sliding property between the cleaning blade and the photosensitive member in an image forming apparatus described later.

  The present inventor considered the relationship between the polyolefin resin contained in the toner particles and the white spot phenomenon, and found that the polyolefin resin contained as a wax component in the toner particles may cause the white spot phenomenon. Obtained. That is, when a conventional electrophotographic photoreceptor is mounted on an image forming apparatus and continuously used, the wax component of the toner particles locally adheres to a specific portion of the photoreceptor, and this portion is It has been found that the portion becomes a poorly charged portion and a white spot generating portion where toner particles do not adhere. The specific part of the photoconductor is a part where the polyolefin resin is likely to adhere chemically and physically, such as a part where surface dangling bonds are locally high and adhesive strength is high, or a part where the surface roughness is locally large. Say.

  Immediately after the photoconductor is manufactured, the entire outermost surface of the photoconductor is in a state where it is relatively difficult for the polyolefin resin to adhere to it, and even if the polyolefin resin does not adhere to the surface, about several thousand to tens of thousands By repeating this image formation, the wax component made of polyolefin resin or the like contained in the toner particles adheres to the surface of the photoreceptor. At this time, the wax component adheres from a specific portion that is relatively easily adhered to the surface of the photoreceptor, but after the wax component is once adhered, the ease with which the wax component adheres to the specific portion increases rapidly. This is because the resin structures that are polymers are easily bonded to each other.

  In the conventional photoconductor, when the image formation of several thousand to several tens of thousands of images was performed, the difference in the amount of the wax component deposited between the specific portion and the other portions was large. This unevenness of the adhesion amount is considered to affect the white spot phenomenon.

  The surface of the photoreceptor is used in a state where it is in sliding contact with a cleaning blade, which will be described later. By continuously performing image formation, the wax component (polyolefin resin, etc.) of the toner particles adheres to the cleaning blade itself. . It is known that when the amount of the wax component adhering to the cleaning blade and the amount of the wax component adhering to the surface of the photoreceptor exceeds a certain level, the occurrence of white spot phenomenon is extremely reduced in the subsequent image formation. It has been. For example, it is known that a combination of a photoreceptor and a cleaning blade that has undergone image formation of several hundred thousand sheets or more results in a so-called “familiar state” and the occurrence of white spot phenomenon is significantly reduced. In this familiar state, the adhesion of the wax component on the surface of the photoconductor becomes an adhesion amount of a certain amount or more as a whole, and the adhesion amount on the cleaning blade also becomes an adhesion amount of a certain amount or more as a whole, It can be considered that the occurrence of the white spot phenomenon is remarkably reduced due to this.

  At the time of image formation of thousands to tens of thousands of images, this “familiarity” is not sufficient, and the uneven adhesion amount of the polyolefin resin on the surface of the photoreceptor is large, and unevenness occurs in the sliding contact state with the blade. It is thought that this leads to a local defect in the adhesion state of the toner particles. Based on such considerations, the inventor of the present application examines a photoreceptor that can sufficiently suppress the occurrence of the white spot phenomenon from the start of use in an image forming apparatus, and confirms the present invention by performing various experiments. It has gained.

  In the photoreceptor 1 according to an embodiment of the present invention, a resin structure 19 made of a polyolefin resin is attached in advance to the entire surface of the coating layer 18. That is, the surface of the photosensitive member 1 does not have a portion where the wax component is easily attached locally, but the resin structure 19 is preliminarily adhered as a whole, and the wax component is uniformly adhered as a whole. It is in an easy state.

For this reason, even when image formation is repeatedly performed by the image forming apparatus, the wax component does not adhere to the surface at a stretch and may settle to a surface state close to a so-called “familiar state” from an early stage after the start of image formation. it can. By using the photoreceptor 1, the occurrence of white spot phenomenon in image formation can be sufficiently suppressed. In the state after argon bombardment, the surface of the coating layer 18 has a hydrogen bond energy of 7 (mN / m) or more and a surface free energy of 45 (mN / m) or more. The argon bombarding process of the coating layer 18 and the process of attaching the polyolefin resin to the coating layer 19 will be described in detail later.

  The photoreceptor 1 can be manufactured by appropriately setting the numerical conditions of the film formation parameters so as to obtain desired characteristics by a vacuum deposited film forming method. In the photoreceptor 1 of this embodiment, specifically, a DC pulse plasma CVD method is employed. The method for producing the electrophotographic photoreceptor of the present invention is not particularly limited, and specifically, AC discharge plasma such as glow discharge method (low frequency plasma CVD), high frequency plasma CVD method, microwave plasma CVD method and the like. A CVD method may be used, or a direct current discharge plasma CVD method, an ECR plasma CVD method, a sputtering method, a vacuum deposition method, an ion plating method, a photo CVD method, a catalytic CVD (HOT wire CVD) method, or the like may be used. Good.

  The charge injection blocking layer 12, the photoconductive layer 14, the intermediate layer 16, and the coating layer 18 in the photoreceptor 1 are formed by using, for example, the plasma CVD apparatus 2 shown in FIGS. FIG. 3 is a schematic cross-sectional side view of an embodiment of a plasma CVD apparatus used for manufacturing the photoreceptor 1. FIG. 4 is a schematic top sectional view of the plasma CVD apparatus shown in FIG.

  The plasma CVD apparatus 2 accommodates the support 3 in a vacuum reaction chamber 4 and further includes a rotating means 5, a source gas supply means 6 and an exhaust means 7.

  The support 3 serves to support the conductive substrate 10 and functions as a first conductor. The support 3 is formed in a hollow shape having a flange portion 30 and is entirely formed of a conductive material similar to the conductive base 10 as a conductor. The support 3 is formed to have a length that can support the two conductive substrates 10, and is detachable from the conductive support 31. Therefore, in the support 3, the two conductive substrates 10 can be taken in and out of the vacuum reaction chamber 4 without directly touching the surfaces of the two supported conductive substrates 10.

The conductive column 31 is entirely formed of a conductive material similar to that of the conductive substrate 10 and is insulated from the plate 42 described later at the center of the vacuum reaction chamber 4 (cylindrical electrode 40 described later). It is fixed via a material 32.

  A DC power supply 34 is connected to the conductive support 31 via a conductive plate 33. The operation of the DC power supply 34 is controlled by the control unit 35. The control unit 35 is configured to supply a pulsed DC voltage to the support 3 via the conductive support 31 by controlling the DC power supply 34 (see FIGS. 5 and 6).

  A heater 37 is accommodated inside the conductive support 31 via a ceramic pipe 36. The ceramic pipe 36 is for ensuring insulation and thermal conductivity. The heater 37 is for heating the conductive substrate 10. As the heater 37, for example, a nichrome wire or a cartridge heater can be used.

  Here, the temperature of the support 3 is monitored, for example, by a thermocouple (not shown) attached to the support 3 or the conductive support 31, and the heater 37 is turned on / off based on the monitoring result of the thermocouple. By turning off, the temperature of the conductive substrate 10 is maintained within a certain range selected from a target range, for example, 200 ° C. or more and 400 ° C. or less.

  The vacuum reaction chamber 4 is a space for forming a deposited film on the conductive substrate 10, and is defined by a cylindrical electrode 40 and a pair of plates 41 and 42. The cylindrical electrode 40 functions as a second conductor, and is formed in a cylindrical shape surrounding the support 3. The cylindrical electrode 40 is formed of a conductive material similar to that of the conductive substrate 10 and is joined to a pair of plates 41 and 42 via insulating members 43 and 44.

  The cylindrical electrode 40 is formed in such a size that the distance D1 between the conductive substrate 10 supported by the support 3 and the cylindrical electrode 40 is 10 mm or more and 100 mm or less.

  The cylindrical electrode 40 is provided with a gas inlet 45 and a plurality of gas blowing holes 46, and is grounded at one end thereof. The cylindrical electrode 40 is not necessarily grounded, and may be connected to a reference power source different from the DC power source 34. When the cylindrical electrode 40 is connected to a reference power supply different from the DC power supply 34, the reference voltage in the reference power supply applies a negative pulse voltage (see FIG. 5) to the support 3 (conductive base 10). When it does, it is set to -1500V or more and 1500V or less, and when applying a positive pulse voltage (refer FIG. 6) with respect to the support body 3 (conductive base | substrate 10), it is set to -1500V or more and 1500V or less. .

The gas inlet 45 is for introducing a raw material gas to be supplied to the vacuum reaction chamber 4, and is connected to the raw material gas supply means 6. The plurality of gas blowing holes 46 are for blowing the source gas introduced into the cylindrical electrode 40 toward the conductive substrate 10, and are arranged at equal intervals in the vertical direction in the figure, and in the circumferential direction. Are arranged at equal intervals. The plurality of gas blowing holes 46 are formed in a circular shape having the same shape, and the hole diameter is, for example, not less than 0.5 mm and not more than 2.0 mm.

  Of course, the diameter, shape, and arrangement of the plurality of gas blowing holes 46 can be changed as appropriate. The plate 41 is for selecting whether the vacuum reaction chamber 4 is opened or closed. By opening and closing the plate 41, the support 3 can be taken in and out of the vacuum reaction chamber 4. ing. The plate 41 is made of a conductive material similar to that of the conductive substrate 10, but the adhesion preventing plate 47 is attached to the lower surface side.

  This prevents a deposited film from being formed on the plate 41. The deposition preventing plate 47 is also formed of a conductive material similar to that of the conductive substrate 10, but the deposition preventing plate 47 is detachable from the plate 41. Therefore, the deposition preventing plate 47 can be cleaned by removing it from the plate 41 and can be used repeatedly.

  The plate 42 serves as a base for the vacuum reaction chamber 4 and is formed of a conductive material similar to that of the conductive substrate 10. The insulating member 44 interposed between the plate 42 and the cylindrical electrode 40 has a role of suppressing occurrence of arc discharge between the cylindrical electrode 40 and the plate 42.

  The plate 42 and the insulating member 44 are provided with gas discharge ports 42A and 44A and a pressure gauge 49. The exhaust ports 42A and 44A are for exhausting the gas inside the vacuum reaction chamber 4, and the pressure gauge 49 connected to the exhaust means 7 is for monitoring the pressure in the vacuum reaction chamber 4. Various known ones can be used.

As shown in FIG. 3, the rotating means 5 is for rotating the support 3, and includes a rotation motor 50 and a rotational force transmission mechanism 51. When film formation is performed by rotating the support 3 by the rotating means 5, the conductive substrate 10 is rotated together with the support 3, so that the source gas is decomposed evenly with respect to the outer periphery of the conductive substrate 10. It becomes possible to deposit components.

  The rotary motor 50 applies a rotational force to the conductive substrate 10. The operation of the rotary motor 50 is controlled so as to rotate the conductive substrate 10 at 1 rpm or more and 10 rpm or less, for example. Various known motors can be used as the rotary motor 50.

  The rotational force transmission mechanism 51 is for transmitting and inputting the rotational force from the rotary motor 50 to the conductive substrate 10, and includes a rotation introduction terminal 52, an insulating shaft member 53, and an insulating flat plate 54. The rotation introduction terminal 52 is for transmitting a rotational force while maintaining the vacuum in the vacuum reaction chamber 4. As such a rotation introduction terminal 52, vacuum seal means such as an oil seal or a mechanical seal can be used with a rotary shaft having a double or triple structure.

  As shown in FIG. 3, the source gas supply means 6 includes a plurality of source gas tanks 60, 61, 62, 63, a plurality of pipes 60A, 61A, 62A, 63A, valves 60B, 61B, 62B, 63B, 60C, 61C. , 62C, 63C, and a plurality of mass flow controllers 60D, 61D, 62D, 63D, which are connected to the cylindrical electrode 40 via a pipe 64 and a gas inlet 45.

Each of the source gas tanks 60 to 63 is filled with, for example, B2H6, H2 (or He), CH4, or SiH4. The valves 60 </ b> B to 63 </ b> B, 60 </ b> C to 63 </ b> C and the mass flow controllers 60 </ b> D to 63 </ b> D are for adjusting the flow rate, composition, and gas pressure of each raw material gas component introduced into the vacuum reaction chamber 4.

  Of course, in the source gas supply means 6, the type of gas to be filled in each source gas tank 60 to 63, or the number of the plurality of source tanks 60 to 63 depends on the type or composition of the film to be formed on the conductive substrate 10. What is necessary is just to select suitably according to.

  The exhaust means 7 is for exhausting the gas in the vacuum reaction chamber 4 to the outside through the gas exhaust ports 42 </ b> A and 44 </ b> A, and includes a mechanical booster pump 71 and a rotary pump 72. These pumps 71 and 72 are controlled by the monitoring result of the pressure gauge 49. That is, the exhaust means 7 can maintain the vacuum reaction chamber 4 in a vacuum based on the monitoring result of the pressure gauge 49, and can set the gas pressure in the vacuum reaction chamber 4 to a target value. The pressure in the vacuum reaction chamber 4 is, for example, 1.0 Pa or more and 100 Pa or less.

  Next, a method for forming a deposited film using the plasma CVD apparatus 2 will be described taking as an example the case where the photoreceptor 1 (see FIG. 1) is manufactured.

  First, when forming a deposited film (a-Si film) on the conductive substrate 10, the plate 41 of the plasma CVD apparatus 2 was removed and a plurality of conductive substrates 10 (two in the drawing) were supported. The support 3 is set inside the vacuum reaction chamber 4 and the plate 41 is attached again.

  In supporting the two conductive bases 10 with respect to the support 3, the lower dummy base 38A, the conductive base 10, the intermediate dummy base 38B, the conductive, The base body 10 and the upper dummy base body 38C are sequentially stacked.

  As each of the dummy bases 38A to 38C, a conductive or insulative base whose surface is subjected to a conductive treatment is selected according to the use of the product. Usually, a cylinder made of the same material as that of the conductive base 10 is used. What was formed in the shape is used.

  Next, the vacuum reaction chamber 4 is sealed, the conductive substrate 10 is rotated by the rotating means 5 via the support 3, the conductive substrate 10 is heated, and the vacuum reaction chamber 4 is depressurized by the exhaust means 7.

  The conductive substrate 10 is heated, for example, by supplying electric power to the heater 37 from the outside to cause the heater 37 to generate heat. The heat generated by the heater 37 raises the temperature of the conductive substrate 10 to a target temperature. The temperature of the conductive substrate 10 is selected depending on the type and composition of the film to be formed on the surface. For example, when forming an a-Si film, the temperature is set to a range of 250 ° C. or higher and 300 ° C. or lower, and the heater 37 It is kept substantially constant by turning on / off.

  On the other hand, the vacuum reaction chamber 4 is depressurized by exhausting the gas from the vacuum reaction chamber 4 through the gas discharge ports 42A and 44A by the exhaust means 7. The degree of decompression of the vacuum reaction chamber 4 is determined by monitoring the pressure in the vacuum reaction chamber 4 with a pressure gauge 49 (see FIG. 2), while the mechanical booster pump 71 (see FIG. 2) and the rotary pump 72 (see FIG. 2). By controlling the operation, the pressure is set to about 10 −3 Pa, for example.

Next, when the temperature of the conductive substrate 10 reaches a desired temperature and the pressure in the vacuum reaction chamber 4 reaches a desired pressure, the source gas is supplied to the vacuum reaction chamber 4 by the source gas supply means 6, and
A pulsed DC voltage is applied between the cylindrical electrode 40 and the support 3.

  As a result, glow discharge occurs between the cylindrical electrode 40 and the support 3 (conductive substrate 10), the source gas component is decomposed, and the decomposed component of the source gas is deposited on the surface of the conductive substrate 10. On the other hand, in the exhaust means 7, the gas pressure in the vacuum reaction chamber 4 is maintained in the target range by controlling the operations of the mechanical booster pump 71 and the rotary pump 72 while monitoring the pressure gauge 49.

  The supply of the raw material gas to the vacuum reaction chamber 4 is performed by controlling the mass flow controllers 60D to 63D while appropriately controlling the open / closed states of the valves 60B to 63B and 60C to 63C. Introducing into the cylindrical electrode 40 through the pipes 60 </ b> A to 63 </ b> A and 64 and the gas introduction port 45 at a desired composition and flow rate. The source gas introduced into the cylindrical electrode 40 is blown out toward the conductive substrate 10 through a plurality of gas blowing holes 46.

  Then, the charge injection blocking layer 11, the photoconductive layer 12, and the surface protective layer are formed on the surface of the conductive substrate 10 by appropriately switching the composition of the source gas by the valves 60B to 63B, 60C to 63C and the mass flow controllers 60D to 63D. 13 are sequentially stacked.

  The application of a pulsed DC voltage between the cylindrical electrode 40 and the support 3 is performed by controlling the DC power supply 34 by the control unit 35. In general, when high-frequency power over the 13.56 MHz RF band is used, ion species generated in the space are accelerated by the electric field and attracted in the direction according to the positive / negative polarity. Since the electric field continuously inverts, before the ionic species reach the conductive substrate 10 or the discharge electrode, recombination is repeated in the space to become a silicon compound such as gas or polysilicon powder again. Exhausted.

  On the other hand, a pulsating DC voltage is applied so that the conductive substrate 10 side has either positive or negative polarity to accelerate cations to collide with the conductive substrate 10, and the impact causes fine irregularities on the surface. When film formation is performed while sputtering, a film having a surface with very little unevenness can be obtained.

  In such a plasma CVD method, in order to obtain an ion sputtering effect efficiently, it is necessary to apply power that avoids continuous reversal of polarity. In addition to the pulse-shaped rectangular wave, a triangular wave DC power and DC voltage are useful. The same effect can be obtained with AC power adjusted so that all voltages have either positive or negative polarity. The polarity of the applied voltage can be freely adjusted in consideration of the film forming speed determined by the density of the ion species and the polarity of the deposited species depending on the kind of the source gas.

  Here, in order to efficiently obtain the ion sputtering effect by the pulse voltage, the potential difference between the support 3 (conductive substrate 10) and the cylindrical electrode 40 is set within a range of 50 V or more and 3000 V or less, for example. In consideration of the film rate, it is preferably in the range of 500V to 3000V.

  More specifically, when the cylindrical electrode 40 is grounded, the control unit 35 has a negative pulse shape within a range of −3000V to −50V with respect to the support (conductive column 31). A DC potential V1 is supplied (see FIG. 5), or a positive pulsed DC potential V1 within a range of 50V to 3000V is supplied (see FIG. 6).

  On the other hand, when the cylindrical electrode 40 is connected to a reference electrode (not shown), the pulsed DC potential V1 supplied to the support (conductive column 31) is determined from the target potential difference ΔV based on the reference power source. Is the difference (ΔV−V2) obtained by subtracting the potential V2 supplied by the above. The potential V2 supplied by the reference power source is set to −1500 V or more and 1500 V or less when a negative pulse voltage (see FIG. 5) is applied to the support 3 (conductive substrate 10). When a positive pulse voltage (see FIG. 6) is applied to the conductive substrate 10), it is set to -1500V or more and 1500V or less.

  The control unit 35 also controls the DC power supply 34 so that the frequency (1 / T (sec)) of the DC voltage is 300 kHz or less and the duty ratio (T1 / T) is 20% or more and 90% or less.

  The duty ratio in the present invention is one cycle (T) of a pulsed DC voltage (the moment when a potential difference is generated between the conductive substrate 10 and the cylindrical electrode 40 as shown in FIGS. 5 and 6). To the time until the next moment when the potential difference occurs). For example, a duty ratio of 20% means that the potential difference occurrence (ON) time in one cycle when applying a pulsed voltage is 20% of the entire cycle.

  Even if the a-Si film, a-SiC film, and aC film obtained by utilizing this ion sputtering effect have a relatively small thickness, the surface has small fine irregularities and high smoothness.

  Here, in forming the charge injection blocking layer 12, the photoconductive layer 14, the intermediate layer 16, and the coating layer 13, the mass flow controllers 60D to 63D and the valves 60B to 63B and 60C to 63C in the source gas supply means 6 are controlled. The raw material gas having the target composition is supplied to the vacuum reaction chamber 4 as described above.

For example, in the formation of the charge injection blocking layer 12, a mixed gas of a Si-containing gas such as SiH4 (silane gas), a dopant-containing gas such as B2H6, and a diluent gas such as hydrogen (H2) or helium (He) is used as the source gas. Used. As the dopant-containing gas, in addition to the boron (B) -containing gas, a nitrogen (N) or oxygen (O) -containing gas can also be used.

In the formation of the photoconductive layer 12, a mixed gas of a Si-containing gas such as SiH4 (silane gas) and a diluent gas such as hydrogen (H2) or helium (He) is used as a source gas. In the photoconductive layer 12, hydrogen gas is used as a diluting gas so that hydrogen (H) and halogen elements (F, Cl) are contained in the film at 1 atom% or more and 40 atom% or less for dangling bond termination, Alternatively, a halogen compound may be included in the source gas.

  In addition, in order to obtain desired characteristics such as electrical characteristics such as dark conductivity and photoconductivity and optical band gap, the source gas includes a periodic table group 13 element (hereinafter referred to as “group 13 element”). Or a group 15 element of the periodic table (hereinafter abbreviated as “group 15 element”), and elements such as carbon (C) and oxygen (O) are included to adjust the above characteristics. You may let them.

  The group 13 element and the group 15 element are desirable in that boron (B) and phosphorus (P) are excellent in covalent bonding and can change the semiconductor characteristics sensitively, and that excellent photosensitivity can be obtained. .

  When the group 13 element and the group 15 element are contained together with elements such as carbon (C) and oxygen (O) in the charge injection blocking layer 11, the content of the group 13 element is 0.1 ppm or more and 20000 ppm. Hereinafter, the content of the Group 15 element is adjusted to be 0.1 ppm or more and 10,000 ppm or less.

  Further, when the group 13 element and the group 15 element are contained in the photoconductive layer 12 together with elements such as carbon (C) and oxygen (O), or the charge injection blocking layer 11 and the photoconductive layer 12 When elements such as carbon (C) and oxygen (O) are not included, the group 13 element is adjusted to 0.01 ppm to 200 ppm, and the group 15 element is adjusted to 0.01 ppm to 100 ppm. . In addition, by changing the content of the Group 13 element or the Group 15 element in the source gas with time, the concentration of these elements may be provided with a gradient over the layer thickness direction. In this case, the content of the Group 13 element and the Group 15 element in the photoconductive layer 12 may be such that the average content in the entire photoconductive layer 12 is within the above range.

  The photoconductive layer 12 may contain microcrystalline silicon (μc-Si) in the a-Si material. When this μc-Si is included, the dark conductivity and photoconductivity are increased. Therefore, there is an advantage that the degree of freedom in designing the photoconductive layer 22 is increased.

  Such μc-Si can be formed by adopting the film formation method described above and changing the film formation conditions. For example, the glow discharge decomposition method can be formed by setting the temperature and DC pulse power of the conductive substrate 10 to be high and increasing the flow rate of hydrogen as a dilution gas.

  Further, in the photoconductive layer 12 containing μc-Si, the same elements as described above (Group 13 element, Group 15 element, carbon (C), oxygen (O), etc.) may be added. Good.

  In the formation of the coating layer 13, in the formation of the coating layer 18, the composition ratio of Si and C in the source gas is changed in time series during the film formation process. As the a-SiC-based source gas, a mixed gas of a Si-containing gas such as SiH 4 (silane gas) and a C-containing gas such as CH 4 is supplied. For example, the ratio of the flow rate of SiH4 gas to the flow rate of CH4 gas is set to SiH4: CH4 = 1: 2 at the beginning of film formation, and the CH4 ratio is gradually increased during film formation. When the coating layer 18 is formed, the magnitude of the pulse voltage is relatively high, for example, −300V to −450V. By making the magnitude of the voltage relatively high, the hardness of the coating layer having a relatively large C atom number ratio can be made relatively large.

When the formation of the coating layer 18 is completed, an argon gas is supplied to the vacuum reaction chamber 4 to perform an argon bombardment process. For example, the argon gas flow rate is 450 sccm, the pressure is 0.5 torr, the DC current value is 0.4 A, and the voltage value is 320 V. Etching with argon ions is performed for 20 seconds.

  In argon bombardment, argon ions are struck against the surface of the coating layer 18, whereby the surface of the coating layer 18 immediately after formation is physically etched. By this argon bombardment, hydrogen atoms bonded to Si atoms and C atoms on the surface of the coating layer 18 are removed, dangling bonds of Si atoms and C atoms appear on the surface, and the surface of the coating layer 18 is chemically highly active. It becomes a state. Further, microscopic irregularities having a molecular level are uniformly formed on the surface of the coating layer 18 by physical etching with argon ions.

    When the argon bombardment is completed, the conductive substrate 10 is extracted from the support 3 and a polyolefin resin is adhered to the surface. In this attaching process, for example, resin particles containing polystyrene or the like are applied to the surface of the coating layer 18 after argon bombardment, and then the resin particles on the surface of the coating layer 18 are physically removed with a wiping tool such as a wiper cloth. Wipe off. By this treatment, the polyolefin resin component contained in the resin particles is attached to the entire surface of the coating layer 18. The entire surface of the coating layer 18 is chemically and physically activated by argon bombardment, and the polyolefin resin structure is adhered to the entire surface.

  In addition, you may perform the adhesion process of the olefin resin to the coating layer 18 using the following image forming apparatuses 100. FIG.

  7 and 8 are a schematic diagram of the image forming apparatus 100 including the photoconductor 1 and a partially enlarged view of the developing device 120 including the photoconductor 1.

  First, as shown in FIGS. 7 and 8, the image forming apparatus 100 includes a developing device 120, a photosensitive member 121, a developing roller 122, a transfer roller 123, cleaners 125 and 126, a charger 127, a developing device 128, a light source (LED). ) 130, a transfer material conveying means 112, and a fixing means 113 are basically provided. The image forming apparatus 100 includes developing devices 120a, 120b, 120c, and 120d corresponding to four colors, and is an example of a tandem color printer.

  In the image forming apparatus 100, the photosensitive member 121 shown in FIGS. 7 and 8 is rotated in the direction of the arrow, and a uniform corona charging is performed on the surface of the photosensitive member 121 by the main charger 127. The irradiated light is irradiated to a document (not shown). Next, the reflected light is guided onto the surface of the photoconductor 121 via a mirror system, a lens system, a filter, and the like, and is projected to form an electrostatic latent image.

  Therefore, the toner image can be formed by supplying the toner 125 from the toner container 111 in the developing device 120 to the electrostatic latent image. On the other hand, the transfer material such as paper and plastic supplied to the photoconductor 121 through the transfer material conveying means 112 including the transfer material passage and the registration roller is transferred to the transfer roller 123 having a transfer / separation charger and the photoconductor. In the gap 121, an electric field having a polarity opposite to that of the toner is applied from the back surface, whereby the toner image on the surface of the photoconductor 121 is transferred to the transfer material and separated from the photoconductor 121 side.

Next, the separated transfer material reaches the fixing device 113 to fix the toner image, and the transfer material is discharged out of the device. Note that residual toner that does not contribute to transfer and remains on the surface of the photoreceptor 121 at the transfer portion reaches the cleaners 125 and 126 and is cleaned by a cleaning blade or the like provided therein. The photoconductor 121 renewed by the above cleaning is further subjected to the same cycle after being given a static elimination exposure from a static elimination light source (not shown). The cleaning blade is made of urethane rubber, and the angle with the photosensitive member is set to be relatively small at about 10 °.

  In the production of the photoconductor 1, the photoconductor after argon bombardment is mounted on the image forming apparatus 100, and toner particles containing a wax component such as polystyrene are adhered to the entire surface, and then physically scraped by a cleaning blade. Thus, the polyolefin resin may be adhered to the entire surface of the coating layer 18.

  A conductive substrate was prepared by mirror-finishing and cleaning the outer peripheral surface of an extraction tube having an outer diameter of 30 mm, a length of 359 mm, and a thickness of 1.5 mm made of an aluminum alloy.

  This was set in the film forming apparatus shown in FIG. 2, and photoconductors A to C including a charge injection blocking layer, a photoconductive layer, an intermediate layer, and a coating layer were manufactured according to the film forming conditions of the above embodiment.

  Each photoconductor was mounted on the above-described image forming apparatus 100 through the following processing to form a so-called black solid image in which toner was adhered to the entire surface, and the number of white spots in the formed image was measured. The number of white spots is a number that can be visually confirmed, and the number of white spots having a size of about φ0.125 mm or more was measured.

  The photoreceptor A does not perform any surface treatment of the coating layer. The photoreceptor B is obtained by performing a bombarding process using H2 gas and then attaching a polyolefin resin to the entire surface using an image forming apparatus. In addition, the photoreceptor C is obtained by performing an argon bombarding process under the conditions of the above-described embodiment and then attaching a polyolefin resin to the entire surface using an image forming apparatus.

  As a result, the number of white spots was 57 on Photoreceptor A where the surface treatment of the coating layer was not performed. Further, in the photoconductor B subjected to the bombard process using H 2 gas, the number of white spots was as small as 10. Further, in the photoconductor C subjected to the argon bombarding process, the number of white spots was more significantly reduced to one. This is because, in the bombardment treatment using hydrogen gas, hydrogen atoms on the surface of the coating layer are removed, and at the same time, hydrogen atoms newly adhere to the coating layer, so the dangling bonds on the surface of the coating layer were argon bombarded. This is probably because there are relatively few cases. In addition, hydrogen ions have a relatively small mass and a relatively small physical etching state compared to argon ions, which is considered to be one of the causes of less white spot reduction after the argon bombardment process.

  The graph shown in FIG. 9 shows, for each of the photoconductors A to C, measured values of surface free energy before mounting the image forming apparatus, and values of surface work and hydrogen bond energy. For the photoconductors B and C, values in a state where the polyolefin resin after the bombardment treatment is not attached are shown.

The value of the surface free energy was measured using a CX-roll type contact angle meter manufactured by Kyowa Interface Science Co., Ltd. and a surface free energy analysis software type EG-11. More specifically, first, by using a CX-roll type contact angle meter manufactured by Kyowa Interface Science Co., Ltd., the values of the surface free energy of the liquid (dispersion force component, dipole component and hydrogen bond component) are already known The contact angle of the toner pellets was measured by a droplet method in a room where the room temperature was controlled in the range of 20 to 24 ° C. using pure water, methylene iodide, and α-bromonaphthalene. Then, based on the surface free energy data of the photoreceptor, the surface work value, the surface free energy value, and the hydrogen bond energy value were calculated based on the extended Fowkes theory. .

  The photoreceptor C has a larger surface free energy (45 mN / m) and a hydrogen bond energy of 7 (mN / m) than the photoreceptors A and B. It can be seen that the surface of the coating layer is generally in a state in which the polyolefin resin or the like easily adheres due to argon bombardment. Thus, by performing the polyolefin resin adhesion treatment after argon bombardment, the polyolefin resin is sufficiently adhered to the surface of the coating layer, and the white spot treatment is sufficiently suppressed.

  The electrophotographic photoreceptor and the image forming apparatus of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various improvements and modifications may be made without departing from the spirit of the present invention. Of course it is good.

1 Photoconductor for electrophotography (photoconductor)
2 Plasma CVD apparatus 3 Support body 4 Vacuum reaction chamber 5 Rotating means 6 Raw material gas supply means 7 Exhaust means 10 Conductive substrate 12 Charge injection blocking layer 14 Photoconductive layer 16 Intermediate layer 18 Covering layer 19 Resin structure 100 Image forming apparatus 120 Development device

Claims (6)

A conductive substrate, a photoconductive layer containing amorphous silicon formed on the conductive substrate, a coating layer containing amorphous silicon carbide formed on the photoconductive layer, and a polyolefin adhered to the surface of the coating layer With resin ,
The electrophotographic photoreceptor , wherein the surface of the coating layer is ion bombarded with argon . A conductive substrate, a photoconductive layer containing amorphous silicon formed on the conductive substrate, a coating layer containing amorphous silicon carbide formed on the photoconductive layer, and a polyolefin adhered to the surface of the coating layer With resin,
The electrophotographic photoreceptor, wherein the coating layer has a hydrogen bond energy on the surface of 7 (mN / m) or more. A conductive substrate, a photoconductive layer containing amorphous silicon formed on the conductive substrate, a coating layer containing amorphous silicon carbide formed on the photoconductive layer, and a polyolefin adhered to the surface of the coating layer With resin,
The electrophotographic photoreceptor, wherein the coating layer has a surface free energy of 45 (mN / m) or more. Forming a photoconductive layer containing amorphous silicon on the surface of the conductive substrate;
Forming a coating layer containing amorphous silicon carbide on the photoconductive layer;
A step of ion bombarding the surface of the multilayer with argon;
And a step of attaching a polyolefin resin to the surface of the multi-layered layer after the ion bombardment treatment.   In the step of attaching the polyolefin resin, resin particles containing a polyolefin resin as a main component are attached to the surface of the multi-layer, and then the resin particles are removed so that the polyolefin on the surface of the multi-layer 6. The method for producing an electrophotographic photoreceptor according to claim 5, wherein a resin is adhered. The electrophotographic photoreceptor according to any one of claims 1 to 3 ,
Charging means for charging the surface of the electrophotographic photoreceptor with static electricity;
Exposure means for irradiating the electrophotographic photoreceptor charged with static electricity with exposure light to form an electrostatic latent image on the surface of the electrophotographic photoreceptor;
A developer for supplying toner to the surface of the electrophotographic photoreceptor on which the electrostatic latent image is formed, and forming a toner image corresponding to the latent image on the surface of the electrophotographic photoreceptor;
A transfer portion for transferring the toner image onto a transfer material;
An image forming apparatus comprising: a cleaning unit that removes the toner remaining on the surface of the electrophotographic photoreceptor after the transfer.

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