JP4270559B2 - Manufacturing method of charging device, charging device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a charging device used in an image forming apparatus using electrophotographic technology such as a copying machine or a laser printer. Specifically, the conductive material or the semiconductor material is formed on the substrate using the fine particles as a mask, and then the conductive material or the semiconductor material attached to the surface of the fine particles together with the fine particles is removed from the substrate. The present invention relates to a charging device having regular fine protrusions, a process cartridge equipped with the charging device, and an image forming apparatus.

  In general, in an image forming apparatus using an electrophotographic method, an apparatus that uses corona discharge is often used in the process of forming an electrostatic latent image. In this process of forming an electronic latent image, it is necessary to uniformly charge the surface of the photoconductor. Therefore, a corona charger such as a corotron method or a scorotron method that includes a wire electrode and a shield electrode is often used. It has been.

  However, the corona charger requires a high-voltage power supply, and there are problems that discharges such as ozone and NOx are generated due to an air discharge phenomenon. In particular, ozone is not only harmful to the human body, but if it stays in the image forming apparatus, it oxidizes the surface of the photoconductor, causing a decrease in the sensitivity of the photoconductor and a deterioration in charging ability. This leads to a decrease in image quality and a deterioration in product life.

  For this reason, in order to solve the above problems, ozone generated in the image forming apparatus is forcibly discharged outside the apparatus, and an apparatus called an ozone filter is installed in the middle of discharging ozone out of the apparatus. A method is adopted in which ozone is adsorbed on the ozone filter and the concentration of ozone discharged out of the apparatus is reduced to a level with no problem.

  However, even if the measures described above are taken, the performance of the ozone filter gradually deteriorates due to the adsorption of ozone, and ozone cannot be removed properly over a long period of use. In order to solve this problem, it is possible to provide an ozone filter with a large adsorption capacity or a large-capacity exhaust fan. In this case, however, the size of the image forming apparatus is increased and the cost is increased. Cause a new problem to occur.

  In order to solve the above problem, as a technical document filed prior to the present invention, microprojections regularly arranged on the substrate surface using a high-energy beam such as a focused ion beam or etching. The electron emission material is arranged so as to be in contact with the microprojections, and an island-like structure of conductive fine particles having a regular pattern is formed as an electron emission portion, and the island-like structure in the emission portion region There is an electron-emitting device that can stably emit electrons with little variation by eliminating variation among the devices (for example, see Patent Document 1).

  In addition, a Si oxide film and a tungsten (W) film are sequentially formed on the Si substrate, and a part of the Si oxide film and the W film are etched into a cylindrical shape having a diameter of about 0.8 μm by a normal photoetching process. To expose a part of And gold (Au) particle | grains are installed in the center part of the exposed Si substrate, Au and a part of Si substrate are made to react, and an AuSi alloy is formed. A mixed gas of SiCl4 and hydrogen is brought into contact with the Si substrate for about 25 minutes, an Si pillar having a height of 800 nm is formed by Si epitaxial growth, and then the Si substrate is immersed in aqua regia etc., thereby removing the AuSi alloy, There is one that forms a columnar structure and provides a field emission electron source with a small gate diameter for lowering the voltage (see, for example, Patent Document 2).

  In addition, it is composed of a multilayer structure of a surface film having pores formed by anodizing one side of an aluminum substrate and a cathode electrode layer remaining without being anodized, and a fine fibrous material such as carbon nanotube. The plurality of pores formed in the alumina film, which is the surface layer of the electron source array, are regular and aligned in the direction of elongation. It is arranged along the extending direction of the holes. In addition, there is one in which a multi-layer structure is immersed in a dispersion of a fine fibrous substance and a predetermined magnetic field is applied to orient the fine fibrous substance and be attracted into pores (for example, (See Patent Document 3).

  In addition, an insulating member having a convex shape with a minute height made of an insulating material is provided on the peripheral surface of the charging member disposed opposite to the image forming body, and a discharge electrode is provided in the valley portions between the convex portions of the insulating member. By connecting a power source to the electrode body and applying a direct current voltage without superimposing an alternating current voltage to achieve uniform charging, the amount of ozone generated from the charging member is reduced to the limit. There is a charging device (see, for example, Patent Document 4).

In addition, an image forming apparatus that reduces the amount of ozone generated by corona discharge from a charger by bringing a brush charger into contact with the photosensitive member, attaching a dividing resistor between the power source and the brush charger, and reducing the voltage. Yes (see, for example, Patent Document 5).
JP 9-35621 A Japanese Patent Laid-Open No. 9-274849 JP 2002-100280 A JP-A-8-234538 Japanese Patent Laid-Open No. 9-22164

  However, in Patent Document 1, since the generation of fine protrusions uses a technique such as a high energy beam such as a focused ion beam or etching, the size and arrangement position of the fine protrusions may not be controlled.

  Moreover, although the said patent document 2 can form a micro protrusion in the controlled position, the said patent document 2 is a film-forming process of two types of films, a photolithography process, and a dry etching process. It cannot be realized without complicated steps such as a gold particle installation step, an epitaxial step, and a wet etching step. Furthermore, the main factor that determines regularity and its fine dimensions is the ability of the photolithography process and the etching process, and in order to form a fine pattern, the capital investment must be considerably high. Absent.

  Moreover, the said patent document 3 utilizes the anodic oxidation of aluminum as a pore formation technique. The aluminum anodic oxidation technique is a technique in which regular pores can be easily obtained without using a photolithography process or an etching process. However, it cannot be denied that the technology has many problems that still need to be solved, such as ensuring uniformity, in order to apply to a large area. Furthermore, although the said patent document 3 is characterized by using a carbon nanotube as an electron emission material, a carbon nanotube is an expensive material. Furthermore, although the technical investigation has been made on orienting carbon nanotubes by applying a magnetic field, the yield cannot be expected if the carbon nanotubes are orientated in the state of being placed in pores.

  In addition, in Patent Document 4, it is necessary to form a convex shape with a small height in an electrode body uniformly and in a state without variations. In order to realize this, a highly accurate machine A processing device is required, and it is difficult to ensure accuracy, and an increase in cost is inevitable.

  In addition, since the above Patent Document 5 does not use the discharge phenomenon in the atmosphere, it can be expected to reduce the amount of ozone generated, but the thin brush in contact with the photoreceptor is used for a long period of time. The brush itself is broken, and the broken piece becomes a foreign substance, which not only adversely affects the mechanical parts that form the periphery of the photoconductor, but also causes a charging failure in the area where the broken brush disappears. As a result, it becomes impossible to uniformly charge the entire photoconductor, which greatly affects the image quality.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a charging device manufacturing method, a charging device, a process cartridge, and an image forming apparatus that can be driven at a low voltage.

  In order to achieve this object, the present invention has the following features.

<Method for Manufacturing Charging Device>
  A method for manufacturing a charging device according to the present invention includes:
In a method for manufacturing a charging device that uniformly charges the surface of an image carrier,
  A fine particle array forming step of forming a fine particle array in which substantially spherical fine particles are arranged in a two-dimensional close-packed manner on a conductive substrate;
  A film forming step of forming a conductive material or a semiconductor material on the conductive substrate using the fine particle array as a mask;
  It is characterized by having.

<Charging device>
  The charging device according to the present invention is:
  It was manufactured by the manufacturing method described above.

<Process cartridge>
  The process cartridge according to the present invention includes:
  The charging device described above is provided.

<Image forming apparatus>
  An image forming apparatus according to the present invention includes:
  An image forming apparatus including the process cartridge described above, wherein the process cartridge is detachable from the image forming apparatus.

An image forming apparatus according to the present invention includes:
  The charging device described above is provided.

According to the present invention , the electron emission efficiency is improved and charging at a low voltage is possible. As a result, the generation of ozone is reduced, the deterioration of image quality is prevented, the life of the image carrier is extended, and In addition, it is possible to eliminate the need for the ozone removing device or to reduce the size thereof.

  First, the charging device of the present invention will be described with reference to FIGS.

  The charging device according to the present invention is a charging device that uniformly charges the surface of the image carrier, and includes minute protrusions (304) arranged in an array at equal intervals, and the shape of the minute protrusions (304 ) Has a shape of any one of a substantially triangular prism, a substantially triangular pyramid, a substantially quadrangular prism, and a substantially quadrangular pyramid. As a result, the electron emission efficiency is improved, and charging at a low voltage is possible. As a result, generation of ozone is reduced, image quality is prevented from being deteriorated, the life of the image carrier is extended, and ozone is removed. It becomes possible to make the apparatus unnecessary or downsized. Examples of the image carrier include a photosensitive drum and an intermediate transfer belt, and the photosensitive drum is suitable as the image carrier.

  Hereinafter, an image forming apparatus according to the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the image forming unit in the image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 schematically suggests the configuration of the image forming apparatus according to the present invention.

  As suggested in FIG. 1, the image forming apparatus according to the present invention includes a photoreceptor (101), a charger (102), an exposure unit (103), a developing unit (104), and a paper feeding unit ( 105), a transfer portion (107), a fixing portion (108), a cleaning blade (109), and a charge eliminating portion (110). The image forming process in the image forming apparatus according to the present invention will be described below with reference to FIG.

  In the image forming apparatus according to the present invention, the surface of the photoconductor (101) is uniformly charged by the charger (102), and writing is performed by the optical signal based on the image data from the exposure unit (103). An electrostatic latent image is formed on the surface of (101). Thereafter, toner or the like is supplied from the developing unit (104) to the surface of the photoreceptor (101), and is electrostatically attracted to the surface of the photoreceptor (101). Then, a sheet (106) is fed from the sheet feeding unit (105), and the fed sheet (106) comes into contact with the photoreceptor (101) on the transfer unit (107), and the transfer unit (107) By applying a charge having a polarity opposite to that of the toner, the toner adsorbed on the photosensitive member (101) is transferred to the paper (106), and the toner is formed on the paper (106) as an image by the fixing unit (108). It will become established. The toner remaining on the photoconductor (101) without being completely transferred onto the paper (106) is cleaned by the cleaning blade (109), and the residual potential on the photoconductor (101) is reduced by the charge eliminating unit (110). The photoconductor (101) returns to the initial state and the next image forming process is performed again.

  Next, the charger (102), which is a feature of the present invention, will be described with reference to FIGS. 2 and 3 schematically suggest the outline of the method of manufacturing the charger (102) according to the present invention.

  FIG. 2 suggests that the fine particles (202) are regularly arranged on the conductive substrate (201). As suggested in FIG. 2, the technique of regularly arranging the fine particles (202) two-dimensionally on the conductive substrate (201) can be easily realized by using a known technique that has already been proposed. For example, in the registered patent No. 28828374, a liquid dispersion medium of fine particles is spread on the substrate surface to form a liquid thin film, the liquid dispersion medium is controlled to decrease, and the liquid thickness is equal to or smaller than the particle diameter size, A technique is disclosed in which fine particles are aggregated two-dimensionally by surface tension acting in the lateral direction when the liquid evaporates.

  In addition, FIG. 3 suggests a schematic view of a configuration in which the step of regularly arranging the fine particles (202) on the conductive substrate (201) is viewed from the top.

  As suggested in FIG. 3, since the fine particles (202) arranged on the conductive substrate (201) serve as a mask, the opening (203) in the general photolithography technique is indicated by hatching. It becomes an area part. That is, only the region of the opening (203) is in close contact with the conductive substrate (201), and a conductive material or a semiconductor material is formed.

  As suggested in FIGS. 2 and 3, the conductive material or the semiconductor material is suggested on the substrate (201) in which the fine particles (202) are arranged on the conductive substrate (201), as shown in FIG. A film will be formed. As suggested in FIG. 4, since the conductive material or the semiconductor material (304) is formed using the fine particles (302) as a mask, the conductive material formed on the surface of the fine particles (302) is naturally formed. The material or the semiconductor material (304) enters the “gap” of the fine particles (302) arranged on the conductive substrate (301), and comes into close contact with the conductive substrate (301) so that the conductive material or the semiconductor material (304). Will be deposited.

  As suggested in FIG. 4, after the conductive material or the semiconductor material (304) is formed, part or all of the fine particles (302) are removed by a known means. Note that the fine particles (302) may be removed by wet etching or polishing. For example, in the case where a silicon wafer is used for the conductive substrate (301), silica is used as the fine particles (302), and tungsten is used as the conductive material (304) to form a film, the removal of the fine particles (302) can be performed by using a fluoride. If an acid is used, only the silica fine particles (302) can be easily removed without affecting other materials.

  In addition, when polystyrene is used as the fine particles (302), it is possible to easily remove only the fine particles (302) by using an organic solvent such as toluene or THF (tetrahydrofuran).

  FIG. 5 suggests a schematic view of the state after only the fine particles (302) suggested in FIG. 4 are removed by the above processing. As suggested in FIG. 3, the gaps that become the openings (203) formed by the fine particles (202) regularly arranged on the conductive substrate (201) are naturally formed and formed there. In addition, as shown in FIG. 5, minute protrusions made of a conductive material or a semiconductor material are very regular and have a very uniform shape and size.

  Note that the shape of the minute protrusions (304, 304 ′) formed on the conductive substrate (301) by the film formation method described above is slightly different as suggested in FIGS. 5 (a) and 5 (b). Because of the difference, the shape of the minute protrusions (304, 304 ′) suggested in FIGS. 5A and 5B will be described below.

  In general, when the incident angle of the component contributing to the film formation to the conductive substrate is vertical or close to the vertical and the distribution of the incident angle is small, the shadowed portion of the fine particles Since the probability of arrival of components that contribute to the film formation is low, it is very fine that faithfully reflects the opening (203) when viewed from the top surface of the conductive substrate, as suggested in FIG. Thus, a projection having a proper shape is formed. FIG. 5A shows the situation at this time. FIG. 5A is a diagram suggesting a state in which a substantially triangular prism-shaped protrusion (304) is formed on the conductive substrate (301). As suggested in FIG. 5A, minute protrusions (304) made of a conductive material or a semiconductor material that faithfully reflects the opening of the fine particle mask are regularly formed on the conductive substrate (301). It will be.

  As suggested in FIG. 5A, in the case where it is desired to form the projections (304) having a fine pattern shape on the conductive substrate (301), it is preferable to use the film forming method described above. Note that bias plasma CVD, collimated sputtering, long throw sputtering, ECR sputtering, and the like are suitable as a film forming method for forming the minute protrusions (304) suggested in FIG. 5A on the conductive substrate (301). Therefore, it may be used by appropriately selecting from these film forming methods.

  In addition, when the distribution of the incident angle of the component contributing to the film formation to the conductive substrate is large and the method has a low vertical incident property, the component contributing to the film formation also wraps around the shadowed part of the fine particles Will happen. As a result, the conductive material or the semiconductor material formed in the gap between the fine particles becomes a protrusion having a slightly skirt shape. FIG. 5B shows the situation at this time. A minute protrusion (304 ′) made of a conductive material or a semiconductor material, which is formed on the conductive substrate (301 ′) while slightly passing through the gap of the fine particle mask, has a shape with a slight skirt. Will be formed regularly.

  As suggested in FIG. 5B, the projection (304 ′) having a substantially triangular pyramid shape with a slight skirt is a projection (304 ′) suggested in FIG. ) Is slightly inferior to the method of forming. However, as suggested in FIG. 5 (b), the protrusion (304 ′) having a slightly skirted shape increases the installation area with the conductive substrate (301 ′). The adhesiveness to ') is excellent, and electrical stability can be expected to improve.

  As suggested in FIG. 5 (b), when it is desired to form the protrusion (304 ′) having a slightly skirted shape on the conductive substrate (301 ′), the above-described film formation method may be used. . Note that plasma CVD, thermal CVD, sputtering, ion beam sputtering, and the like are suitable as a film formation method for forming the minute protrusions (304 ′) suggested in FIG. 5B on the conductive substrate (301 ′). Therefore, it may be used by appropriately selecting from these film forming methods.

  Note that the configuration suggested in FIG. 5 is a case where fine protrusions (304, 304 ′) are formed on a conductive substrate (301, 301 ′) by regularly arranging fine particles in a two-dimensional fine shape. As suggested in FIG. 6, fine particles (402) are regularly arranged in a two-dimensional matrix on a conductive substrate (401), and minute protrusions are provided using openings (403) in the same manner as described above. It is also possible to configure. FIG. 7 shows the shape of the protrusion when the opening (403) suggested in FIG. 6 is used.

  FIG. 7A is a diagram suggesting a state in which a substantially quadrangular prism-shaped protrusion (504) is formed on the conductive substrate (501). As suggested in FIG. 7A, a minute protrusion made of a conductive material or a semiconductor material that faithfully reflects the opening (403) of the fine particle mask suggested in FIG. 6 on the conductive substrate (501). (504) will be formed regularly.

  As suggested in FIG. 7A, in the case where it is desired to form the projection (504) having a fine pattern shape on the conductive substrate (501), it is preferable to use the film forming method described above. Note that bias plasma CVD, collimated sputtering, long throw sputtering, ECR sputtering, and the like are suitable as a film forming method for forming the minute protrusions (504) suggested in FIG. 7A on the conductive substrate (501). Therefore, it may be used by appropriately selecting from these film forming methods.

  In addition, when the distribution of the incident angle of the component contributing to the film formation to the conductive substrate is large and the method has a low vertical incident property, the component contributing to the film formation also wraps around the shadowed part of the fine particles Will happen. As a result, the conductive material or the semiconductor material formed in the gap between the fine particles becomes a protrusion having a slightly skirt shape. FIG. 7B shows the situation at this time. A minute protrusion (504 ′) made of a conductive material or a semiconductor material, which is formed on the conductive substrate (501 ′) while slightly passing through the gap of the fine particle mask, has a shape with a slight skirt. Will be formed regularly.

  As suggested in FIG. 7B, the projection (504 ′) having a substantially quadrangular pyramid shape with a slight skirt is a projection (504 ′) suggested in FIG. ) Is slightly inferior to the method of forming. However, as suggested in FIG. 7B, the projection (504 ′) having a slightly skirted shape increases the installation area with the conductive substrate (501 ′), and thus the conductive substrate (501). The adhesiveness to ') is excellent, and electrical stability can be expected to improve.

  As suggested in FIG. 7B, when the projection (504 ′) having a slightly skirted shape is formed on the conductive substrate (501 ′), the above-described film formation method may be used. . Note that plasma CVD, thermal CVD, sputtering, ion beam sputtering, and the like are suitable as a film formation method for forming the minute protrusion (504 ′) suggested in FIG. 7B on the conductive substrate (501 ′). Therefore, it may be used by appropriately selecting from these film forming methods.

  As described above, the charger according to the present invention that uniformly charges the surface of the photoconductor is formed by arranging minute protrusions in an array at equal intervals, and the shape of the minute protrusions is approximately triangular prism or approximately triangular. By forming with a shape of any one of a cone, a substantially quadrangular prism, and a substantially quadrangular pyramid, it becomes possible to exhibit a necessary charging ability at a low voltage. For this reason, it is possible to suppress the generation of ozone, and as a result, it is possible to suppress the generation of substances that degrade the image quality, and it is possible to maintain high image quality. Furthermore, it is possible to reduce the size of the ozone removing mechanism portion mounted on the image forming apparatus, and it is possible to realize low cost. Further, each side surface of the minute protrusion formed on the charger according to the present invention is a concave surface, so that the mechanical strength of each minute protrusion is increased and it is possible to form a highly reliable charger. Become. As a result, the reliability of the entire image forming apparatus can be improved.

  Further, the minute protrusions formed on the charger are obtained by forming a conductive material or a semiconductor material using an aggregate formed by two-dimensionally arranging substantially spherical fine particles as a mask. Therefore, expensive equipment is unnecessary, fine processing is possible using an energy saving process, and it is possible to form a charger with high reliability and durability and excellent electron emission effect. This makes it possible to suppress the generation of ozone and to construct an image forming apparatus having high image quality and high reliability.

  In addition, by using any one of silica, alumina, titanium oxide, zirconium oxide, tantalum pentoxide, gadolinium oxide, yttrium oxide, and polystyrene as the fine particles, fine particles having a shape close to a true sphere and having a small variation in particle size are obtained. A pattern that is easily available and arranged with high accuracy can be easily formed on the substrate, and as a result, a high-quality charger can be formed.

  In addition, by using any one of tungsten, silicon, titanium nitride, and amorphous carbon as the conductive material or semiconductor material, a charger with high reliability and durability and excellent electron emission efficiency is formed. Therefore, it is possible to construct an image forming apparatus that generates less ozone.

  The configurations suggested in FIGS. 5 and 7 suggest the case where all the fine particles have been removed. However, it does not necessarily function as a charger without removing all of the fine particles, and also has different advantages. Will be. That is, the film thickness of the conductive material or semiconductor material to be formed is set to about the radius of the fine particles, and after the film formation, the fine particles are etched from the surface side to remove just about half of the fine particle film. A configuration schematically suggesting the configuration in this case is suggested in FIG.

  As suggested in FIG. 8, the gap between the fine particles (602) arranged on the conductive substrate (601) is filled with a conductive material or a semiconductor material (604), and the fine particle film (602) By removing about half, the gap between the fine particle film (601) remaining in a film thickness of about half is not formed into a shape in which only minute protrusions exist on the conductive substrate (601), but a conductive material or a semiconductor material. (604). As suggested in FIG. 8, by constructing a charger formed by removing fine particles in the thickness direction to the same thickness as that of a conductive material or a semiconductor material, mechanical strength, and It is possible to form a charger having excellent electrical strength.

  Note that the charger formed through the above-described steps easily emits electrons from minute protrusions formed on the conductive substrate by applying a voltage to the conductive substrate. In addition, the shape and size of the minute protrusions are very uniform, and the arrangement positions are regularly arranged, so that even with a large area charger, the electron emission characteristics of the entire surface are uniform. Therefore, the charger is excellent in reliability and durability.

  It should be noted that regular formation of minute protrusion patterns on a conductive substrate can be realized by making full use of the conventional photolithography process and dry etching process. However, trying to make the size of the minute protrusion pattern very small requires a high-resolution photolithography process, and at the same time, a dry etching process that realizes a fine pattern. Not only increases technical difficulties, but also requires very expensive manufacturing equipment.

  However, if the charger is formed by the above-described process, it is possible to determine how fine a protrusion pattern can be formed on the conductive substrate by the size of the fine particles. Fine particles can be easily obtained, and it becomes easy to regularly arrange the spherical fine particles on the conductive substrate.

  In the present invention using such a fine particle array as a mask, the gap between the fine particle arrays is an important dimension determining factor. Therefore, when the gap between the spherical fine particle arrays is about several hundred nm, a regular pattern of about several tens of nm is obtained. It will be easily obtained. Attempting to realize such an extremely fine pattern by a conventional photolithography process is very difficult and inevitably requires a high cost.

  As described above, the present invention forms minute protrusions regularly arranged on a substrate with high controllability by a very simple process using a readily available material and using a technique that can be easily realized. Can be done.

  Furthermore, according to the present invention, high-quality fine particle arrangement can be realized by using a dispersion liquid. That is, even in the case of ultrafine particles that tend to aggregate in the dry state, the advantages of the state of the dispersion are utilized to the maximum, thereby preventing aggregation by improving dispersibility and controlling pH, for example, ions to be added By appropriately selecting and controlling the species, it is possible to use the isoelectric point relationship. As a result, it is possible to form a high-quality fine particle array. This point will be described in detail below.

  In general, when fine particles made of a metal oxide are immersed in water, the fine particles have a positive or negative charge, and when an electric field is present, they move in the direction of the opposing electric field. This phenomenon is an electrophoresis phenomenon. By this electrophoresis phenomenon, it is possible to know the charge of fine particles in water, that is, the presence of an interface potential (zeta potential). This interfacial potential varies greatly depending on the pH of the fine particle-water system. In general, taking the pH of the aqueous system on the horizontal axis and the interfacial potential on the vertical axis, the interfacial potential changes depending on the pH of the aqueous system, and the pH of the aqueous system at which the interface potential “0” is cut is defined as the “isoelectric point”. To do. From this phenomenon, the interface potential on the surface of the metal oxide fine particles generally has a positive polarity on the acidic side and a negative polarity on the alkaline side. However, this isoelectric point varies greatly depending on the material. For example, “2.0” for colloidal silica, “6.7” for titanium oxide (synthetic rutile), and “9.0” for α-alumina are introduced. Has been.

  In other words, the greater the distance from the isoelectric point, the greater the interfacial potential, the more toward the acidic side, the more positive the interface potential, and vice versa. Head for. This can be controlled by pH. The pH can be controlled with good controllability by adding acid or alkali. In the present invention, this phenomenon is actively utilized, and aggregation of fine particles can be effectively prevented in the state of a dispersion. As a result, even when the dispersion liquid is supplied to the substrate, the fine particles are present in a non-aggregated state, so that it is possible to easily realize a high-quality arrangement state in the subsequent arrangement process. This phenomenon is an advantage that cannot be obtained by a dry process.

(Example)
Next, the processing steps described above will be described in detail using the following examples. Since the present invention has a significant feature in the charger (102) itself, a method for manufacturing the charger (102) will be described.

(Example 1)
First, the first embodiment will be described.

(1: Formation of fine particle mask)
A 4-inch P-type single crystal silicon wafer was used as the conductive substrate, and silica having a particle size of 1 μm was used as the fine particles. Silica was dispersed in pure water at a concentration of 5%, and it was dropped on the entire surface of a 4-inch P-type single crystal silicon wafer and dried in an atmosphere at room temperature of 24 ° C. and humidity of 80%. Under these conditions, it has been confirmed by prior experiments that a two-dimensional close-packed silica aggregate can be obtained.

(2: Formation of electron emission material)
In the first embodiment, tungsten is used as the electron emission material. As a forming method, a collimated sputtering method having a tungsten target was used. The collimator was an aggregate of cells having a regular hexagonal shape with the opposite side being ½ inch and having an aspect ratio of “2”. Film formation was performed for 1 minute by this film formation method.

(3: Removal of fine particle mask)
After deposition of the electron emission material, the sample was immersed in 15% hydrofluoric acid for 3 minutes to remove the entire fine particle mask.

(4: Formation of charger)
Electrodes were formed on a substrate having a minute projection array made of an electron emission material obtained by the above steps, and a charger that can insulate necessary portions and apply a high voltage was formed.

(5: Evaluation with actual machine)
The scorotron charger of a general electrophotographic image forming apparatus was removed, and the charger obtained by the above process was mounted to actually output an image. The surface of the photoreceptor could be charged to a desired potential with an applied voltage of about 1/5 that of a scorotron charger. Further, the generation of ozone was reduced to about 1/10 of the case where the scorotron charger was used.

(Example 2)
Next, a second embodiment will be described.

(1: Formation of fine particle mask)
As in the first example, a 4-inch P-type single crystal silicon wafer was used as the conductive substrate, and silica having a particle size of 1 μm was used as the fine particles. Silica was dispersed in pure water at a concentration of 5%, which was dropped on the entire surface of a 4-inch P-type single crystal silicon wafer, and dried in an atmosphere of room temperature 24 ° C. and humidity 80%. Under these conditions, it has been confirmed by prior experiments that a two-dimensional close-packed silica aggregate can be obtained.

(2: Formation of electron emission material)
In the second embodiment, unlike the first embodiment, titanium nitride is used as the electron emission material. Further, a long throw sputtering method having a titanium nitride target was used as a forming method. The distance between the target and the substrate is an apparatus configuration of 600 mm. Film formation was performed for 2 minutes by this film formation method.

(3: Removal of fine particle mask)
As in the first example, after the film formation of the electron emission material, the sample was immersed in 15% hydrofluoric acid for 3 minutes to remove all the fine particle mask.

(4: Formation of charger)
Electrodes were formed on a substrate having a minute projection array made of an electron emission material obtained by the above steps, and a charger that can insulate necessary portions and apply a high voltage was formed.

(5: Evaluation with actual machine)
The scorotron charger of a general electrophotographic image forming apparatus was removed, and the charger obtained by the above process was mounted to actually output an image. The surface of the photosensitive member could be charged to a desired potential with an applied voltage of about 1/5 when a scorotron charger was used. Further, the generation of ozone was reduced to about 1/10 of the case where the scorotron charger was used.

(Example 3)
Next, a third embodiment will be described.

(1: Formation of fine particle mask)
In the third example, unlike the first and second examples, titanium oxide was used as the fine particles, and the dispersion was made acidic. This will be described in detail below.

  Alumina fine particles (average particle size = 2 μm) were dispersed in 15 mg liquid in 500 ml of pure water, and 200 μl of hydrochloric acid was added to control the liquidity to be acidic. The pH of the dispersion was “2.55”. The reason for this is as follows. That is, since the isoelectric point of the titanium oxide fine particles is generally said to be “6.7”, the interface potential is almost “0” in a neutral (pH = 7.0) solution such as pure water. Is close to. Therefore, in order to migrate the titanium oxide fine particles with good controllability, it is effective to increase the interface potential by setting the liquidity to the acidic side or the alkaline side. As in this embodiment, by using a solution system, the liquid property can be controlled, and application to a wide range of materials becomes possible. Unlike the first embodiment, titanium having a size of 50 mm × 50 mm and a thickness of 0.5 mm was used as the conductive substrate. Further, titanium oxide having a particle size of 2 μm was used as the fine particles.

  A dispersion liquid in which titanium oxide fine particles were dispersed was dropped on the entire surface of a titanium substrate having a size of 50 mm × 50 mm and a thickness of 0.5 mm, and dried in an atmosphere at room temperature of 24 ° C. and humidity of 80%. Under these conditions, it has been confirmed in a prior experiment that a two-dimensional close-packed titanium oxide aggregate can be obtained.

(2: Formation of electron emission material)
Similar to the second embodiment, titanium nitride was used as the electron emission material in the third embodiment. However, unlike the second embodiment, an ECR sputtering method using titanium nitride as a target was used as a forming method. Film formation was performed for 2 minutes by this film formation method.

(3: Removal of fine particle mask)
In the third embodiment, an alkali etching technique is used as means for removing only titanium oxide fine particles without damaging titanium as a conductive substrate or titanium nitride as an electron emission material. That is, it was immersed in a 1N aqueous potassium hydroxide solution for 3 minutes to remove all of the titanium oxide fine particles.

(4: Formation of charger)
Electrodes were formed on a substrate having a minute projection array made of an electron emission material obtained by the above steps, and a charger that can insulate necessary portions and apply a high voltage was formed.

(5: Evaluation with actual machine)
The scorotron charger of a general electrophotographic image forming apparatus was removed, and the charger obtained by the above process was mounted to actually output an image. The surface of the photosensitive member could be charged to a desired potential with an applied voltage of about 1/5 when a scorotron charger was used. Further, the generation of ozone was reduced to about 1/10 of the case where the scorotron charger was used.

(Example 4)
Next, a fourth embodiment will be described.

(1: Formation of fine particle mask)
In the fourth example, a 4-inch P-type single crystal silicon wafer was used as the conductive substrate, and polystyrene having a particle diameter of 1 μm was used as the fine particles. Polystyrene was dispersed in pure water at a concentration of 6% and dropped onto the entire surface of a 4-inch P-type single crystal silicon wafer, and dried in an atmosphere at room temperature of 24 ° C. and humidity of 80%. Under these conditions, it has been confirmed by prior experiments that a two-dimensional close-packed silica aggregate can be obtained.

(2: Formation of electron emission material)
In the fourth embodiment, hydrogenated amorphous silicon was used as the electron emission material. The formation method used was a general plasma CVD method using monosilane and hydrogen as source gases. The substrate temperature was 150 ° C. Film formation was performed for 4 minutes by this film formation method.

(3: Removal of fine particle mask)
In the fourth embodiment, metal oxide fine particles as in the above-described embodiments are not used, and therefore removal by acid or alkali is not suitable. Organic solvents are effective. Therefore, acetone was used in the fourth example. It was immersed in acetone for 10 minutes to remove all polystyrene fine particles.

(4: Formation of charger)
Electrodes were formed on a substrate having a minute projection array made of an electron emission material obtained by the above steps, and a charger that can insulate necessary portions and apply a high voltage was formed.

(5: Evaluation with actual machine)
The scorotron charger of a general electrophotographic image forming apparatus was removed, and the charger obtained by the above process was mounted to actually output an image. The surface of the photosensitive member could be charged to a desired potential with an applied voltage of about 1/5 when a scorotron charger was used. Moreover, the generation of ozone was reduced to about 1/10 of the case where the scorotron charger was used.

(Example 5)
Next, a fifth embodiment will be described.

(1: Formation of fine particle mask)
In the fifth example, a 4-inch P-type single crystal silicon wafer was used as the conductive substrate, and polystyrene having a particle diameter of 1 μm was used as the fine particles. Polystyrene was dispersed in pure water at a concentration of 6% and dropped onto the entire surface of a 4-inch P-type single crystal silicon wafer, and dried in an atmosphere at room temperature of 24 ° C. and humidity of 80%. Under these conditions, it has been confirmed by prior experiments that a two-dimensional close-packed silica aggregate can be obtained.

(2: Formation of electron emission material)
In the fifth embodiment, amorphous carbon obtained by ECR-CVD using CO2 and CH4 as raw materials was used as the electron emission material.

(3: Removal of fine particle mask)
In the fifth embodiment, unlike the embodiment described above, a method of removing a part of the fine particle mask is used instead of removing all of the fine particle mask. That is, a container containing THF (tetrahydrofuran) is allowed to stand in a draft chamber, and the sample that has been completed up to the formation of the electron emission material is set on a fixed stand having a precision drive stage. The sample is moved to a position where about half the thickness of the polystyrene fine particle mask is removed and held for 5 minutes. By this step, a structure in which the polystyrene fine particle mask was reduced to about half the original thickness as suggested in FIG. 7 and the gap between the polystyrene fine particle masks was filled with amorphous carbon was obtained.

(4: Formation of charger)
Electrodes were formed on a substrate having a minute projection array made of an electron emission material obtained by the above steps, and a charger that can insulate necessary portions and apply a high voltage was formed.

(5: Evaluation with actual machine)
The scorotron charger of a general electrophotographic image forming apparatus was removed, and the charger obtained by the above process was mounted to actually output an image. The surface of the photosensitive member could be charged to a desired potential with an applied voltage of about 1/5 when a scorotron charger was used. Further, the generation of ozone was reduced to about 1/10 of the case where the scorotron charger was used.

Next, a second embodiment will be described.
In the first embodiment, the charger which is a feature of the present invention is mounted on an image forming apparatus as suggested in FIG. 1, but in the second embodiment, the charger which is a feature of the present invention is mounted on a process. It is characterized by being mounted on a cartridge. The process cartridge according to the second embodiment will be described below with reference to FIGS.

  As suggested in FIGS. 9 to 11, the process cartridge (1) in the second embodiment includes a process cartridge frame (2a, 2b), a photosensitive drum (3) as a latent image carrier, It has a charging module (charging device that is a feature of the present invention) (4), a developing module (5) that is a developing means, and a cleaning module (6) that is a cleaning means. Configured. In the process cartridge (1), the photosensitive drum (3), the charging module (4), the developing module (5), and the cleaning module (6) can be replaced with new ones in module units. Has been built.

  The process cartridge frame (2a, 2b) has an open position in which the first process cartridge frame (2a) and the second process cartridge frame (2b) are centered on the engaging portion (2c). And a closed position are rotatably engaged. In the closed position, the first process cartridge frame (2a) and the second process cartridge frame (2b) are arranged so that the photosensitive drum (3) cannot be removed. It is built to surround. The engaging portion (2c) is provided with a protrusion and a hole in the first process cartridge frame (2a) and the second process cartridge frame (2b), and the protrusion is inserted into the hole. It is constructed so that it can be engaged and held on the protrusion with a C-ring. Furthermore, in the closed position, the frame body position with respect to the hole provided in the place where the first process cartridge frame (2a) and the second process cartridge frame (2b) overlap. The first process cartridge frame (2a) or the second process cartridge frame (2b) is positioned by penetrating with the two pins planted in the fixing member (74) (see FIG. 11). It will be fixed at the same time. Thus, the process cartridge can be easily separated by assembling the process cartridge without integrally forming the first process cartridge frame (2a) and the second process cartridge frame (2b). It is possible to construct the photosensitive drum (3), the charging module (4), the developing module (5), and the cleaning module (6) so that the units can be individually replaced.

  Further, the process cartridge (1) can be configured to be provided with a detecting means. As suggested in FIG. 10, the process cartridge (1) has a temperature for detecting the temperature and humidity in the process cartridge (1). A humidity sensor (21), a potential sensor (22) for detecting the potential of the photosensitive drum (3), and a toner concentration sensor (23) for detecting the amount of toner developed on the photosensitive drum (3) after development. It is also possible to arrange these.

  The temperature / humidity sensor (21) is disposed on the second process cartridge frame (2b) and has a positive temperature characteristic, for example, platinum, tungsten, nichrome, Kanthal, or a negative humidity characteristic, for example, Sic. It is detected by a detection element such as a fine wire such as (carbonized diatom) or TaN (tantalum nitride) or a minute temperature sensitive element such as a thin film or thermistor. In addition, although the temperature / humidity sensor (21) in a present Example was arrange | positioned in the upper part of the 2nd frame (2b) as suggested in FIG. 10, it is not limited to this position, Various It is possible to change and arrange.

  The potential sensor (22) is disposed on the second process cartridge frame (2b), and includes a potential detection unit and a control unit. The potential sensor (22) can detect the surface potential of the photosensitive drum (3) by being arranged at a distance of 1 to 3 mm from the surface of the photosensitive drum (3) of the object to be measured. It is. The potential sensor (22) is located above the first process cartridge frame (2a) and between the charging module (4) and the developing module (5), as suggested in FIG. In addition, it is arranged so as to be on the downstream side of the laser beam to be exposed. At this position, the potential of the photosensitive drum (3) on which a latent image that becomes a patch-like solid black portion is formed is detected, and the detected signal is transmitted to the image forming apparatus main body through a signal line. The control unit provided in the apparatus main body determines the magnitude of the developing bias applied by the developing module (5), and controls the power supply to apply the voltage. This potential sensor (22) can also be constructed to detect the potential of the photosensitive drum (3) as the white background portion and control the light amount and exposure time of the laser beam forming the solid black portion. It is.

  The toner density sensor (23) is arranged on the first process cartridge frame (2a), and visualizes the latent image of the solid black portion formed outside the image forming area on the photosensitive drum (3) with toner. The toner adhesion amount of the solid black portion is optically detected as an image density, and the detection result is transmitted as a signal to a control unit included in the image forming apparatus main body. The toner density sensor (23) is composed of a light emitting element (for example, LED) and a light receiving element, and the light receiving element receives the light amount of the light emitting element reflected from the solid black portion, and is on the photosensitive drum (3). The amount of toner is detected. The toner density sensor (23) detects the amount of toner on the photosensitive drum (3), and is accommodated in the developing module (5) from the table recorded in the control unit provided in the main body of the image forming apparatus. The toner density of the developing developer is determined. The toner density sensor (23) in this embodiment is provided on the downstream side in the developing module (5).

  Each sensor related to the photosensitive drum (3) is arranged in the process cartridge frame (2a, 2b), so that the process means can be easily replaced. In addition, it is possible to reduce the cost of each replaceable process means.

  Further, as suggested in FIG. 10, the process cartridge (1) according to the present invention can be provided with a pre-transfer charge eliminating device (25) and a pre-cleaning charge eliminating device (26). The pre-transfer neutralization device (25) is provided on the upstream side of the transfer region, and the pre-cleaning neutralization device (26) is provided on the downstream side of the transfer region and on the upstream side of the cleaning device, thereby eliminating the charge on the photosensitive drum (3). By fading, transfer or cleaning becomes easy. In particular, the pre-cleaning static eliminator (26) facilitates cleaning of residual toner that has not been transferred onto the photosensitive drum (3). Note that the pre-transfer static eliminator (25) and the pre-cleaning static eliminator (26) are provided with light emitting diodes (LD), LEDs, electroluminescence (EL), fluorescent lamps, etc. as issuing means. In this case, the photosensitive drum (3) is exposed to extinguish charges on the photosensitive drum (3). The issuing means is preferably EL or LD. Furthermore, the structure is simple and it is more preferable to use EL. It is also possible to provide a pre-charge neutralization device upstream of the charging device. Thereby, the residual potential of the photosensitive drum (3) can be erased, and the photosensitive drum (3) can be uniformly charged.

  The process cartridge (1) can be replaced by removing any of the subunits of the photosensitive drum (3), the charging module (4), the developing module (5), and the cleaning module (6). It is configured to be possible. In particular, the charging module (4), the developing module (5), and the cleaning module (6) are all constructed so that they can be detached and attached independently from other modules. ing.

  As described above, the charger according to the present invention can be mounted on the process cartridge. By mounting this process cartridge on the image forming apparatus, it is possible to obtain the same effect as in the first embodiment.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited only to the above-described embodiment, and various modifications are made without departing from the gist of the present invention. Implementation is possible. For example, the present invention has the greatest feature in a charger having a fine projection shape with periodicity, and the ozone filter can be miniaturized by mounting this charger in an image forming apparatus. Is possible. In addition, except for the merit that the power supply of the charger is a low voltage type, it is possible to apply a configuration mounted on a normal image forming apparatus as the configuration of the portion other than the charger. The charger described in the above embodiment is not limited to the image forming apparatus described above, and can be mounted on various image forming apparatuses.

  The charging device according to the present invention can be applied to an image forming apparatus such as a process cartridge, a copying machine, or a printer because the entire surface is uniform and can emit electrons with high efficiency.

FIG. 2 is a diagram suggesting a configuration of an image forming apparatus equipped with a charger that is a feature of the present invention. It is a figure which suggests the state which arrange | positioned the microparticles | fine-particles regularly and two-dimensionally finely on the electroconductive board | substrate. It is a top view suggesting a state where fine particles are regularly arranged in a two-dimensional fine pattern on a conductive substrate. It is a figure which suggests the structure after depositing a conductive material or a semiconductor material on fine particles. FIG. 5 is a diagram suggesting a state after removing only fine particles from the state suggested in FIG. 4, (a) is a diagram in the case of providing a substantially triangular prism-shaped protrusion, and (b) is a substantially triangular pyramid shape. It is a figure at the time of providing this processus | protrusion. It is a figure which suggests the state which arrange | positioned the microparticles | fine-particles regularly on the electroconductive board | substrate in the two-dimensional matrix form. FIG. 7 is a diagram suggesting a state after removing only fine particles from the state suggested in FIG. 6, (a) is a diagram in the case of providing a substantially quadrangular prism-shaped protrusion, and (b) is a schematic quadrangular pyramid. It is a figure at the time of providing the shape protrusion. It is a figure which suggests the case where about half of the fine particle film is removed. It is a figure which suggests the structure of the process cartridge at the time of mounting the charger concerning this invention. It is a schematic sectional drawing which suggests the structure of the process cartridge at the time of mounting the charger concerning this invention. It is a figure which suggests the state at the time of open | releasing each subunit which comprises the process cartridge at the time of mounting the charger concerning this invention from a process cartridge frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Process cartridge 2a, 2b Process cartridge frame 2c Engagement part 3 Photosensitive drum (photosensitive body)
4 Charging module (charger)
5 Development module (developer)
6 Cleaning module (cleaning blade)
DESCRIPTION OF SYMBOLS 21 Temperature / humidity sensor 22 Electric potential sensor 23 Toner density sensor 25 Pre-transfer static elimination apparatus 26 Pre-cleaning static elimination apparatus 101 Photoconductor 102 Charger 103 Exposure part 104 Developing part 105 Paper feed part 106 Paper 107 Transfer part 108 Fixing part 109 Cleaning blade 110 Static neutralization Portion 201, 301, 401, 501, 601 Conductive substrate 202, 302, 402, 602 Fine particle 203, 403 Opening 304, 604 Conductive material or semiconductor material 304, 504 Minute protrusion

Claims (12)

In a method for manufacturing a charging device that uniformly charges the surface of an image carrier,
  A fine particle array forming step of forming a fine particle array in which substantially spherical fine particles are arranged in a two-dimensional close-packed manner on a conductive substrate;
  A film forming step of forming a conductive material or a semiconductor material on the conductive substrate using the fine particle array as a mask;
  A method for manufacturing a charging device, comprising: 2. The charging device according to claim 1, wherein the substantially spherical fine particles are any one of silica, alumina, titanium oxide, zirconium oxide, tantalum pentoxide, gadolinium oxide, yttrium oxide, and polystyrene. Manufacturing method . 2. The method for manufacturing a charging device according to claim 1, wherein the conductive material or the semiconductor material is any one of tungsten, silicon, titanium nitride, and amorphous carbon. After the deposition step, manufacture of the charging device according to claim 1, wherein the electrically conductive material or, until said thickness and the thickness of the same degree of a semiconductor material, and removing the fine particles in the thickness direction Way . The method for manufacturing a charging device according to claim 4 , wherein the fine particles are removed in the thickness direction by wet etching. The method for manufacturing a charging device according to claim 4 , wherein the fine particles are removed in a thickness direction by using mechanical polishing. The fine particle array forming step includes:
2. The method of manufacturing a charging device according to claim 1, wherein a fine particle array that is two-dimensionally arranged in close-packing is formed by supplying a dispersion liquid in which the substantially spherical fine particles are dispersed. When using fine particles made of a metal oxide as the substantially spherical fine particles,
  The pH of the dispersion is controlled to be more acidic or alkaline than the pH at which the interfacial potential of the fine particles composed of the metal oxide to be dispersed becomes zero, and the interfacial potential of the fine particles composed of the metal oxide is increased. A method for manufacturing a charging device according to claim 7. A charging device manufactured by the manufacturing method according to claim 1. A process cartridge comprising the charging device according to claim 9 . 11. An image forming apparatus equipped with the process cartridge according to claim 10 , wherein the process cartridge is detachable from the image forming apparatus. An image forming apparatus comprising the charging device according to claim 9 .

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