JP2007042390A - Electric contact material manufacturing method and electric contact material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric contact material manufacturing method and an electric contact material capable of appropriately setting amount of graphite on the surface of a metal body. <P>SOLUTION: A photosensitive drum 13 is charged with electricity by a static charging mechanism 14, the photosensitive drum 13 after the static charging is rotated for a given number of times, and then, an exposure mechanism 15 irradiates light on the photosensitive drum 13 to form a latent electrostatic image on the surface of the drum 13. The photosensitive drum 13 is further rotated with a prescribed angle, a development mechanism 16 develops charged graphite particles on the photosensitive drum, and the graphite particles are adhered to the latent electrostatic image of the photosensitive drum. Next, a part with the graphite particles adhered of the photosensitive drum 13 is made rotated up to a position where it faces a sample 11, and a transfer mechanism 17 transfers the graphite particles to the sample 11 by giving reverse charge on the rear surface of the sample 11. Then, the graphite particles transferred to the sample 11 are fixed to the sample surface by a fixing mechanism 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrical contact material manufacturing method and electrical contact material used for, for example, a switching contact of an electrical circuit.

  Conventionally, as an electrical contact material used for a switching contact of an electrical circuit, for example, a sintered silver-graphite alloy as disclosed in Patent Documents 1 to 3 has been widely used. Graphite originally has little weldability, is extremely chemically stable, and has a very high lubricating action. Therefore, since a silver-graphite alloy containing graphite becomes a highly wear-resistant member, if a silver-graphite alloy is used as an electrical contact material, it is not necessary to use a lubricant such as grease or oil. -Graphite alloys are used as greaseless sliding contact materials.

Here, when a sintered material is used, silver can contain a large amount of graphite, but if the graphite content relative to silver increases, the strength of the electrical contact material decreases and becomes brittle. . Therefore, when considering the strength aspect of the electrical contact material, a method of producing an electrical contact material containing graphite by plating silver containing graphite on a base material such as copper, for example, is employed. .
JP 2002-53919 A JP-A-1996-13065 JP 63-7345 A

  By the way, in the electrical contact material containing graphite, for example, if the amount of graphite on the surface of the metal body is too large, the amount of the metal body exposed on the surface of the metal body is reduced, which is not preferable as the electrical contact material. Therefore, it is necessary to provide a balance between the slidability of graphite and the metal contact of the metal body. For this purpose, the amount of graphite on the surface of the metal body needs to be set to an appropriate amount. However, regardless of whether the graphite-containing electrical contact material is made of a sintered material or plated, it is difficult to distribute graphite particles on the surface of the metal body. Was desired.

  An object of the present invention is to provide an electrical contact material manufacturing method and an electrical contact material capable of setting an appropriate amount of graphite on the surface of a metal body.

  In order to solve the above-described problems, in the invention described in claim 1, an electrostatic latent image is formed on the surface of the photoconductor by the procedure of charging the photoconductor that can rotate around the center point and the amount of light that is exposed to the photoconductor. A procedure for forming an image, a procedure for developing graphite particles imparted with charge to the photoconductor on which the electrostatic latent image has been formed, and a metal body that is a transfer destination of the graphite particles, Applying a reverse charge from the back side of the body to transfer the graphite particles developed on the photoconductor to the metal body, and fixing the graphite particles transferred to the metal body on the surface of the metal body The gist is to provide a procedure.

  According to the present invention, the surface of the photosensitive member is first charged, the charged photosensitive member is rotated by a predetermined amount, the charged portion is disposed at a position where light can be received, the charged portion is exposed, and the electrostatic latent image is exposed. Form an image. Subsequently, the photosensitive member after the electrostatic latent image is formed is further rotated by a predetermined amount, the electrostatic latent image portion is disposed at a position where graphite development is possible, and the graphite particles are developed on the electrostatic latent image. Then, the photoconductor after the graphite development is further rotated by a predetermined amount, the development site is arranged at a position where the graphite can be transferred, and a reverse charge is applied from the back side of the metal body, so that the graphite developed on the photoconductor Transcript to. After the graphite transfer, the graphite transferred to the metal body is fixed to the metal body. By performing the above processing continuously in accordance with the rotation of the photoconductor, the graphite particles are dispersed on the surface of the metal body, and it is fixed to the metal body.

  By the way, the process of charging a photoconductor, exposing it, developing the particles on the photoconductor and transferring the particles to the transfer target is a technology that can uniformly disperse the particles to be transferred onto the transfer target. It is. Therefore, if the graphite particles are dispersed on the metal body using this treatment, the graphite particles can be dispersed almost uniformly on the metal body, so that the amount of graphite on the surface of the metal body is less likely to vary. It becomes possible to make the amount of graphite on the surface of the metal body an appropriate amount. Therefore, since the wear resistance of the metal body is determined by the amount of graphite on the surface of the metal body, if the amount of graphite on the surface of the metal body is an appropriate amount, the wear resistance of the metal body (electrical contact material) is set to a suitable value. Is done.

  In the invention according to claim 2, in the invention according to claim 1, the procedure for fixing the graphite particles to the metal body is a procedure for subjecting the metal body to a high temperature treatment to melt the surface of the metal body. It is a summary.

  According to this invention, in addition to the effect of the invention described in claim 1, when the metal body is subjected to a high temperature treatment, the surface of the metal body is melted, so that the periphery of the graphite is filled with the molten metal body. Therefore, for example, graphite that is simply caught on the metal body is firmly fixed to the metal body, and thereby the graphite is fixed to the metal body. Therefore, it becomes difficult for graphite to fall off from the metal body, and the wear resistance of the electrical contact material is improved.

  According to a third aspect of the present invention, in the first aspect of the invention, the procedure for fixing the graphite particles to the metal body is performed by applying a pressure treatment to the surface of the metal body. The gist is that it is a procedure for plastic deformation.

  According to the present invention, in addition to the effect of the invention of the first aspect, when the metal body is subjected to pressure treatment, the surface of the metal body is plastically deformed, so that the periphery of the graphite is filled with the plastic body. Therefore, for example, graphite that is simply caught on the metal body is firmly fixed to the metal body, and thereby the graphite is fixed to the metal body. Therefore, it becomes difficult for graphite to fall off from the metal body, and the wear resistance of the electrical contact material is improved. Further, when the metal body is subjected to pressure treatment, the surface of the metal body is hardened and the hardness is increased, which is effective in further improving wear resistance.

  The invention according to claim 4 is summarized in that, in the invention according to any one of claims 1 to 3, the graphite particles are coated with an insulating film made of a resin.

  According to this invention, in addition to the action of the invention according to any one of claims 1 to 3, the graphite particles are easily charged when the graphite particles are coated with an insulating film. The charging property is improved. Therefore, the graphite can be easily attached to the photoreceptor, and the effect of uniformly dispersing the graphite is further enhanced.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the metal body is formed by forming a graphite-containing metal plating on a part of or the entire surface of the base material. The gist is that the graphite is transferred to the surface of the metal plating.

  According to this invention, in addition to the action of the invention according to any one of claims 1 to 4, for example, even if a treatment for increasing the amount of graphite is performed, the amount of graphite increases in the metal plating. Therefore, since the material component of the base material remains as it is, the strength of the base material does not decrease, and the strength of the electrical contact material using the base material as a base material is sufficiently ensured.

  In the invention according to claim 6, the metal is formed on a part or the whole of the surface of the base material, and the graphite is solidified and rubbed against a rough portion of the surface of the metal plating, thereby the graphite is The gist is to fix to the surface of the metal plating.

  According to the present invention, when the graphite is fixed to the metal plating by rubbing the bar with the graphite hardened on the surface of the metal plating, for example, if the strength and the number of times the bar is rubbed are changed, the amount of graphite corresponding to the metal plating is changed. It will be attached to the surface. Therefore, if a method of rubbing a bar material in which graphite is hardened against metal plating, an appropriate amount of graphite can be fixed to the metal plating by a simple operation. Therefore, since the wear resistance of the metal plating is determined by the amount of graphite on the plating surface, if the amount of graphite on the plating surface is an appropriate amount, the wear resistance of the metal body (electrical contact material) is set to a suitable value. .

  According to a seventh aspect of the present invention, a photosensitive drum rotatable around a support shaft is charged, an electrostatic latent image is formed on the surface of the photosensitive drum by the amount of light exposed to the photosensitive drum, and the electrostatic By developing the charged graphite particles on the photoconductor on which the latent image has been formed and transferring the metal body to which the graphite particles are transferred, by applying a reverse charge from the back side of the metal body, It is an electrical contact material produced by transferring the graphite particles developed on a photosensitive drum to the metal body, and fixing the graphite particles transferred to the metal body on the surface of the metal body. To do. According to the present invention, an effect similar to that of the first aspect can be obtained.

  In the invention according to claim 8, the metal is formed on a part or the whole of the surface of the base material, and the graphite is solidified and rubbed against a rough portion of the surface of the metal plating, thereby the graphite is The gist is that the electrical contact material is manufactured by fixing on the surface of the metal plating. According to the present invention, an effect similar to that of the second aspect can be obtained.

  According to the present invention, the amount of graphite on the surface of the metal body can be set to an appropriate amount.

(First embodiment)
Hereinafter, a first embodiment of an electrical contact material manufacturing method and an electrical contact material embodying the present invention will be described with reference to FIGS.

(Plating treatment)
FIG. 1 is a schematic configuration diagram showing a schematic configuration of the electroplating apparatus 1. The electroplating apparatus 1 applies a DC voltage between the base material 2 and an electrode (not shown) immersed in the plating solution 4 while the base material 2 to be plated is immersed in the plating solution 4 in the plating basket 3. In this apparatus, a direct current is passed through the base material 2 to form a metal plating layer on the surface of the base material 2. At this time, the base material 2 becomes a cathode (minus), the electrode becomes an anode (plus), and metal ions in the plating solution 4 are attracted to the base material 2, thereby forming metal plating on the base material 2. In this example, a solution in which silver cyanide is melted is used as the plating solution 4, and silver plating 8 (see FIG. 2) is formed as metal plating on the surface of the base material 2 such as copper.

  The base material 2 is wound around a roll and installed outside the plating basket 3. Through holes 5a and 5b are respectively formed in the lower portions of the pair of side walls 5 of the plating basket 3, and the base material 2 is introduced into the plating bowl 3 from one through hole 5a during plating and plated while being conveyed. Then, it is continuously led out from the other through hole 5b to the outside of the plating rod 3. Further, the plating solution 4 leaking from the through holes 5 a and 5 b is stored in a storage portion 6 below the plating basket 3, and the plating solution 4 is pumped up to the plating basket 3 by the pump device 7. The silver plating 8 corresponds to metal plating.

(Graphite dispersion treatment)
FIG. 3 is a schematic configuration diagram showing a schematic configuration of the electrical contact material manufacturing apparatus 9. The electrical contact material manufacturing apparatus 9 uses light to attach graphite particles (hereinafter referred to as graphite particles 10) to a photoreceptor and forms a silver plating 8 on a base material 2 (hereinafter referred to as a sample 11). It is an electrophotographic manufacturing apparatus that manufactures the electrical contact material 12 (see FIG. 8B) by transferring graphite particles. In addition, the electrical contact material manufacturing apparatus 9 employs a drum type in which the graphite particles 10 are attached to the photosensitive drum 13 that can rotate around the center point O. The photosensitive drum 13 corresponds to a photosensitive member.

  The electrical contact material manufacturing apparatus 9 includes a charging mechanism 14 for charging the photosensitive drum 13, an exposure mechanism 15 for exposing the charged photosensitive drum 13, and a developing mechanism 16 for developing the graphite particles 10 on the exposed photosensitive drum 13. It has. The electrical contact material manufacturing apparatus 9 is also transferred with a transfer mechanism 17 that transfers the graphite particles 10 on the photosensitive drum 13 to the sample 11, and a fixing mechanism 18 that fixes the graphite particles 10 attached to the sample 11 to the sample 11. A cleaning mechanism 19 is provided for removing the graphite particles 10 that have not been removed from the photosensitive drum 13.

  The charging mechanism 14 is a mechanism that uniformly charges the entire surface of the photosensitive drum 13 by a charging unit such as a charging roller, and charges the photosensitive drum 13 to the positive electrode or the negative electrode depending on the model. The charging mechanism 14 charges the photosensitive drum 13 when the photosensitive drum 13 rotates. For example, when the charging mechanism 14 is a negative charge type, the surface of the photosensitive drum 13 is charged to the negative electrode as shown in FIG. Become.

  As shown in FIG. 5, the exposure mechanism 15 irradiates a photosensitive drum 13 that has been charged with light such as an LED (Light Emitting Diode) or a laser, with a graphite transfer pattern, so that an electrostatic latent image 20 is formed on the surface of the photosensitive drum 13. It is a mechanism that forms. The electrostatic latent image 20 is a portion where a charge opposite to the portion not irradiated with light is generated due to the charge of the portion irradiated with light falling to the ground. Adheres. Further, the graphite transfer pattern corresponds to a spraying range (spreading area) of the graphite particles transferred to the sample 11 and can be appropriately changed using the input device 21 of the electrical contact material manufacturing apparatus 9.

  In addition, since the strength of the electrostatic latent image 20 changes depending on the amount of exposure light, the amount of graphite attached to the photosensitive drum 13 (electrostatic latent image 20) changes accordingly in the subsequent development process. Accordingly, by adjusting the amount of exposure light using the input device 21, the transfer amount of the graphite particles 10, that is, the density of the transferred graphite particles 10 can be adjusted by changing the strength of the electrostatic latent image 20. Is possible. That is, when the electrostatic latent image 20 is strongly charged, the transfer amount of the graphite particles 10 increases. On the other hand, when the electrostatic latent image 20 is weakly charged, the transfer amount of the graphite particles 10 decreases.

  The developing mechanism 16 agitates the graphite particles 10 with a developer unit or the like, for example, and charges the graphite particles 10 to the opposite side of the electrostatic latent image 20, and attaches the charged graphite particles 10 to the photosensitive drum 13. It is a mechanism to make. Since the charged graphite particles 10 are charged to the opposite side of the electrostatic latent image 20 (in this example, the negative electrode), when the photosensitive drum 13 passes through the developing mechanism 16, the photosensitive drum 13 has a structure as shown in FIG. It adheres to the electrostatic latent image 20.

  The developing mechanism 16 has a charge adjusting function for adjusting the strength of charging of the graphite particles 10. Here, if the charge intensity applied to the graphite particles 10 changes, the amount of graphite attached to the photosensitive drum 13 during development changes. Accordingly, it is possible to adjust the transfer amount of the graphite particles 10 by adjusting the charging strength of the graphite particles 10 using the input device 21. Here, when the charge of the graphite particles 10 is strong, the transfer amount of the graphite particles 10 increases. On the other hand, when the charge of the graphite particles 10 is weak, the transfer amount of the graphite particles 10 decreases.

  As shown in FIG. 7, when the photosensitive drum 13 having the graphite particles 10 attached passes through the position opposite to the sample 11, the transfer mechanism 17 transports the sample 11 and reverse charges from the back surface of the sample 11 (in this example, the positive electrode). ) To transfer the graphite particles 10 to the surface 8a of the silver plating 8. As a result, on the surface 8a of the silver plating 8, as shown in FIG. 8A, the graphite particles 10 are dispersed on the silver plating 8 in a distribution range corresponding to the graphite transfer pattern. Note that not all of the graphite particles 10 on the photosensitive drum 13 are transferred to the sample 11, but a part (for example, about 80%) is transferred to the sample 11, and the rest is attached as residual graphite on the photosensitive drum 13. It becomes a state.

  The fixing mechanism 18 is a mechanism for fixing the graphite particles 10 transferred to the sample 11 to the sample 11 (silver plating 8) by, for example, fusion, fusion welding, pressure welding, or the like. As the fixing process, for example, the surface 8a of the silver plating 8 is melted to fill the unevenness on the plating surface to fix the graphite, and the surface 8a is applied to the surface 8a of the silver plating 8 by applying pressure. There is a pressure treatment in which graphite is fixed by plastic deformation. When this type of fixing treatment is performed, the graphite particles 10 are strongly fixed to the silver plating 8 as shown in FIG. 8B, and the graphite is less likely to fall off from the electrical contact material 12 as a product. Effective for ensuring wear resistance.

  The cleaning mechanism 19 is a mechanism for removing the graphite particles 10 remaining on the photosensitive drum 13 without being transferred to the sample 11 and preparing for the next transfer. Since the graphite particles 10 are electrically attached to the photosensitive drum 13, the cleaning mechanism 19 removes the attached charges of the graphite particles 10 attached to the photosensitive drum 13 with a charger or light, so that the graphite particles 10 are removed. It is easy to detach from 13. After removing the adhered charge of the remaining graphite particles 10, the cleaning mechanism 19 removes the graphite particles 10 remaining on the photosensitive drum 13 using a cleaner brush.

  By the way, the process of charging the photosensitive drum 13, exposing it, developing the graphite particles 10 on the photosensitive drum 13, transferring it to the sample 11 and fixing it is also understood from the fact that it is used in a laser printer or the like. Thus, this is a technique capable of uniformly dispersing the graphite particles 10 on the sample 11. Therefore, if the graphite particles 10 are dispersed on the sample 11 using this process, the graphite particles 10 are almost uniformly dispersed on the surface of the sample 11. For this reason, it is difficult for the amount of graphite dispersed on the surface of the sample 11 to vary, and the amount of graphite on the surface of the sample 11 can be made appropriate. Further, since the wear resistance of the electrical contact material 12 is determined by the amount of graphite on the surface, if the amount of graphite on the surface is an appropriate amount, the wear resistance of the electrical contact material 12 is between the sliding property and the metal contact. It becomes a suitable value balanced.

  Furthermore, if the charge intensity of the photosensitive drum 13 is changed in the exposure process or the charge intensity of the graphite particles 10 is changed in the development process, the amount of graphite transferred to the sample 11 changes. It is possible to arbitrarily set the amount of graphite sprayed on the sample 11 by changing the setting of the charging intensity. Therefore, the user can arbitrarily (freely) control the amount of graphite sprayed on the sample 11, and the set amount of graphite can be evenly sprayed on the sample 11.

  Here, the surface graphite area ratio S is appropriately determined depending on the amount of graphite on the plating surface table. FIG. 9 is a graph showing the relationship between the surface graphite area ratio S and the number of times of durability N. The endurance number N of the contact material 12 is determined. Accordingly, the durability number N differs depending on the target product specifications. However, in order to ensure sufficient wear resistance, the durability number N is secured 1 million times as can be seen from the graph of FIG. It is desirable to set the surface graphite area ratio S to .45 or more.

(Laser processing)
FIG. 10 is a schematic configuration diagram showing a schematic configuration of the laser device 22. The laser device 22 as the fixing mechanism 18 is a device that melts a workpiece by irradiating the workpiece with a laser as a high temperature treatment (reflow treatment). The laser device 22 includes a processing chamber 23 for containing the electrical contact material 12 in a sealed state, a laser irradiation unit 24 attached in the processing chamber 23, and a vacuum pump 25 for reducing the processing chamber 23 to a vacuum (non-oxidizing atmosphere). And. The laser device 22 includes a drive mechanism 26 that reciprocates the laser irradiation unit 24 in a predetermined direction, and a conveyance mechanism 27 that conveys the workpiece in a direction orthogonal to the reciprocation direction of the laser irradiation unit 24.

  Next, the procedure for melting the electrical contact material 12 with the laser device 22 will be described. When performing the laser processing, the electrical contact material 12 cut into a flat plate of a predetermined area after the plating processing is processed in the processing chamber 23 of the laser device 22. Then, the inside of the processing chamber 23 is depressurized to a vacuum state by the vacuum pump 25. Note that the processing chamber 23 is not necessarily in a vacuum state, and a non-oxidizing atmosphere is sufficient.

  After the inside of the processing chamber 23 is in a vacuum state, the laser irradiation unit 24 starts the forward movement by the drive mechanism 26, and in the course of the forward movement, irradiates the electric contact material 12 set in the processing chamber 23 with the laser. Then, the first line is melted on the surface 8 a of the silver plating 8. Here, since the melting point of silver is about 962 ° C. and the melting point of the graphite particles 10 is about 3550 ° C., the melting temperature by the laser irradiation unit 24 is lower than the melting point of the base material 2 and only the silver plating 8 is melted. Therefore, it is set to about 1000 ° C to 1500 ° C.

  When the laser irradiation unit 24 finishes one forward movement, the transport mechanism 27 transports the electrical contact material 12 by a predetermined amount. Subsequently, the laser irradiation unit 24 starts to move backward, and in the process of moving backward, the silver plating 8 is irradiated with laser to melt the second line on the surface 8a of the silver plating 8. When the laser irradiation unit 24 completes one backward movement, the transport mechanism 27 transports the electrical contact material 12 again by a predetermined amount, and thereafter, the laser irradiation by the laser irradiation unit 24 and the electrical contact material 12 are performed in the same manner as described above. The conveyance is repeated until laser irradiation is performed on all the lines of the silver plating 8.

  Therefore, since the surface 8a of the silver plating 8 is melted, the melted silver component flows into the gaps between the graphite particles 10, and the melted silver component is uneven in the silver plating 8 as shown in FIG. The graphite particles 10 are filled with a silver component. Therefore, the molten silver component strongly fixes the graphite particles 10 in the silver plating 8 around the periphery, and the fixability of the graphite particles 10 is enhanced. This makes it difficult for the graphite particles 10 to fall off the silver plating 8 and improves the wear resistance of the silver plating 8 (electrical contact material 12).

(Heat treatment by furnace)
FIG. 11 is a schematic configuration diagram showing a schematic configuration of the furnace device 28. The method of melting the surface 8a of the silver plating 8 is not limited to the laser processing described above, and may be, for example, a heat treatment using a furnace device 28 as the fixing mechanism 18. The furnace apparatus 28 is an apparatus that puts a workpiece into a furnace 29 and heats the inside of the furnace 29 to melt the workpiece. The furnace device 28 includes a processing chamber 30 that houses the electrical contact material 12 in a sealed state, a heat source 31 that raises the temperature in the processing chamber 30, and a vacuum pump 32 that places the processing chamber 30 in a vacuum (non-oxidizing atmosphere) state. And.

  Next, the procedure for melting the electrical contact material 12 in the furnace device 28 will be described. When the heat treatment by the furnace 29 is performed, the electrical contact material 12 cut into a flat plate having a predetermined area after the plating process is processed in the furnace 29. Then, the inside of the processing chamber 30 is decompressed to a vacuum state by the vacuum pump 32. Note that the processing chamber 30 is not necessarily in a vacuum state as in the case of the laser processing, and a non-oxidizing atmosphere is sufficient. Various heat sources 31 such as a high-frequency heating heat source are employed.

  After the inside of the processing chamber 30 is in a vacuum state, when the power source is turned on to the heat source 31 and the temperature of the processing chamber 30 is increased, the surface 8a of the silver plating 8 is melted. Here, the melting temperature of the heat treatment in the furnace 29 is set to about 1000 ° C. to 1500 ° C. for the same reason in the case of the laser treatment. Accordingly, even when the furnace 29 is used, the surface 8a of the silver plating 8 is melted, whereby the fixability of the graphite particles 10 is increased, and the wear resistance of the silver plating 8 is improved as in the case of laser processing.

(Pressure treatment)
FIG. 12 is a schematic configuration diagram showing a schematic configuration of the pressure treatment device 33. The pressure processing device 33 as the fixing mechanism 18 is a device that plastically deforms the surface of the workpiece by pressing the workpiece with a roller or the like. The pressurizing apparatus 33 includes a support base 34 on which the electrical contact material 12 is placed, a roller 35 capable of rotating, and a roller 35 that is pressed against the electrical contact material 12 with a predetermined pressure in a predetermined direction. And a drive mechanism 36 that moves in the direction of arrow A in FIG.

  Next, the procedure of pressurizing the electrical contact material 12 with the pressurizing apparatus 33 to plastically deform the surface of the electrical contact material 12 will be described. When performing the pressurizing process, the plate is cut into a predetermined area after plating. The made electrical contact material 12 is set on the support base 34. Then, the drive mechanism 36 presses the roller 35 against the electrical contact material 12 with a predetermined pressure, and in this state, the drive mechanism 36 moves the roller 35 in the direction of arrow A1 in FIG. Apply pressure to. At this time, the pressure value (predetermined pressure) applied to the surface 8a of the silver plating 8 by the roller 35 is set to a value such that the surface 8a of the silver plating 8 is plastically deformed.

  Accordingly, since the surface 8a of the silver plating 8 is plastically deformed by the pressurizing process, the plastically deformed silver component is buried around the graphite particles 10 as shown in FIG. Accordingly, the plastically deformed silver component strongly fixes the graphite particles 10 in the silver plating 8 around the periphery, and the fixability of the graphite particles 10 is enhanced. This makes it difficult for the graphite particles 10 to fall off the silver plating 8 and improves the wear resistance of the silver plating 8 (electrical contact material 12). Further, when the graphite particles 10 in the silver plating 8 are fixed by the pressure treatment, the surface hardness of the silver plating 8 is increased by the pressure treatment, so that the graphite particles 10 are firmly fixed to the silver plating 8. Thus, the wear resistance of the silver plating 8 is further increased.

(Insulation coating treatment)
FIG. 13 is a longitudinal sectional view of the graphite particle 10. The graphite particles 10 may be coated with, for example, an insulating film 37 around the graphite particles 10. The insulating film 37 is made of, for example, a resin material and has a property of being easily charged. Accordingly, the graphite particles 10 coated with the insulating film 37 are easily charged due to the action of the insulating film 37 during the development process. For example, the amount of graphite that is not charged and cannot be attached to the photosensitive drum 13 is reduced. Effective for uniform dispersion. Further, if the heat treatment is performed in the fixing step, the insulating film 37 melts and adheres to the silver plating 8, so that the fixability of the graphite particles 10 is improved.

According to the configuration of the first embodiment, the following effects can be obtained.
(1) Since the graphite particles 10 are dispersed on the sample 11 using an electrophotographic system capable of uniformly transferring the transferred material, the graphite particles 10 are uniformly dispersed on the silver plating 8 of the sample 11 Therefore, an appropriate amount of graphite particles 10 without variation can be distributed on the silver plating 8. In addition, since the wear resistance of the electrical contact material 12 is determined by the amount of graphite on the surface, if the amount of graphite on the surface is an appropriate amount, the wear resistance of the electrical contact material 12 can be reduced between slidability and metal contact. Can be set to a suitable value balanced.

  (2) The amount of graphite transferred to the sample 11 changes if the amount of light is changed in the exposure process or the charge level of the graphite particles 10 is changed in the development process. Therefore, the charge level of the graphite particles 10 is set. By changing, the amount of graphite sprayed on the sample 11 can be arbitrarily set. Therefore, the user can freely control the wear resistance value of the electrical contact material 12, and various types of electrical contact materials 12 can be manufactured according to the target product specifications.

  (3) When a high temperature treatment is used in the fixing step, the surface 8a of the silver plating 8 is melted by the high temperature treatment, but the melted silver component fills the unevenness on the surface 8a of the silver plating 8 and The graphite particles 10 are strongly fixed on the surface 8a. Accordingly, since many graphite particles 10 are strongly attached to the silver plating 8, the fixability of the graphite particles 10 to the silver plating 8 can be improved. Therefore, if the fixability of the graphite particles 10 increases, the wear resistance of the silver plating 8 (electrical contact material 12) can be improved.

  (4) When pressure treatment is used in the fixing step, the surface 8a of the silver plating 8 is plastically deformed by the pressure treatment, but the plastically deformed silver component is buried around the graphite particles 10 at that time, The plastically deformed silver component strongly fixes the graphite particles 10 in the silver plating 8 around. Accordingly, since many graphite particles 10 are strongly attached to the silver plating 8, the fixability of the graphite particles 10 to the silver plating 8 can be improved. Therefore, if the fixability of the graphite particles 10 increases, the wear resistance of the silver plating 8 (electrical contact material 12) can be improved. Further, when the graphite particles 10 in the silver plating 8 are fixed by the pressure treatment, the surface hardness of the silver plating 8 is increased by the pressure treatment, so that the graphite particles 10 are firmly fixed on the silver plating 8. Thus, the wear resistance of the silver plating 8 can be further increased.

  (5) When the graphite particles 10 coated with the insulating film 37 are used, since the insulating film 37 acts and the graphite particles 10 are easily charged during the development process, for example, the graphite particles 10 are attached to the photosensitive drum 13 without being charged. This reduces the amount of graphite and has an effect on uniform dispersion of graphite. Further, if the heat treatment is performed in the fixing step, the insulating film 37 melts and adheres to the silver plating 8, so that the fixability of the graphite particles 10 can be further enhanced.

  (6) The silver plating 8 is formed on the surface of the base material 2, and the graphite particles 10 are dispersed and fixed on the plating to distribute the graphite particles 10 on the plating surface. Therefore, even if the process of increasing the amount of graphite particles 10 is performed, the amount of graphite particles 10 increases on the silver plating 8, so that the material component of the base material 2 remains as it is. Therefore, even if the graphite particles 10 are increased, the strength of the base material 2 remains the same. Therefore, the strength of the electrical contact material 12 based on the base material 2 is not affected by the graphite increase, and the electrical contact material. The strength of 12 can be sufficiently secured.

(7) Since the silver plating 8 has high electrical conductivity as its plating characteristic, the metal plating applied to the electrical contact material 12 is the silver plating 8 to provide the electrical contact material 12 having high electrical conductivity. be able to.
(Second Embodiment)
Next, a second embodiment of the electrical contact material manufacturing method and electrical contact material embodying the present invention will be described with reference to FIGS. This example is different from the first embodiment only in the method of applying an appropriate amount of graphite particles 10 to the sample 11 (silver plating 8), and the same parts as those in the first embodiment are denoted by the same reference numerals. Detailed description will be omitted, and only different parts will be described.

(Rubbing of graphite rod)
FIG. 14 is an explanatory diagram of a graphite fixing method using the graphite rod 38. By the way, in order to rub the graphite rod 38 against the silver plating 8, the surface 8a of the silver plating 8 needs to be rough. However, since the matte plating has a rough surface, the silver plating 8 of the present example. The matte plating is adopted. Thus, if matte plating is used for the silver plating 8, the uneven shape of the surface 8a of the silver plating 8 becomes rough as shown in FIG. 14, and the graphite particles 10 are easily caught. The graphite rod 38 corresponds to a bar material.

  By the way, the reason why the uneven shape on the surface of the matte plating is rough is that, for example, when forming a glossy plating by electroplating, an additive for smoothing the unevenness of the plated surface is mixed. Since seed additives do not enter, it is considered that metal ions in the plating solution 4 are unevenly accumulated on the base material 2 during plating. Therefore, in the case of matte plating, the surface of the base material 2 has a variation in the accumulation of silver, which forms the surface irregularities of the silver plating 8.

  The graphite rod 38 is a rod obtained by hardening graphite particles (graphite) 10 with an adhesive or the like, and has a cylindrical shape in this example. When this graphite rod 38 is rubbed against the surface 8 a of the silver plating 8, the graphite particles 10 are caught on the surface irregularities of the silver plating 8 and are fixed to the surface 8 a of the silver plating 8 as shown in FIG. 15. Therefore, it becomes possible to fix the graphite particles 10 to the silver plating 8 by a simple method, which is effective in simplifying the work when dispersing the graphite particles 10 in the silver plating 8 and shortening the work time. .

  By the way, in the method of dispersing and fixing powdery graphite particles on the surface 8a of the silver plating 8, since the graphite particles are powdery, the possibility of flying off the surface 8a due to wind or the like cannot be denied. However, the method in which the solid graphite rod 38 is rubbed against the silver plating 8 to fix the graphite particles 10 to the silver plating 8 fixes the solid graphite mass to the silver plating 8, so that the graphite particles fly away by wind or the like. There is also an advantage that is unlikely to be such a situation. Note that after the graphite particles 10 are rubbed against the silver plating 8, the fixing property of the graphite particles 10 may be improved by subjecting the silver plating 8 to a high temperature treatment or a heat treatment.

(Overcurrent application processing)
FIG. 16 is a schematic configuration diagram showing a schematic configuration of the electroplating apparatus 1 having another configuration. The method of roughening the surface 8a of the silver plating 8 is not limited to the matte plating of the silver plating 8, and a method of flowing an overcurrent in the initial stage of electroplating may be used. This will be described below. In the electroplating apparatus 1 of this example, the plating rod 3 is divided into two regions by an intermediate partition wall 39, and the base material 2 is composed of the first plating rod 3a and the second plating rod 3b at the time of electroplating. It is immersed in the plating solution 4 in each basket in order. In the electroplating apparatus 1 of this example, an overcurrent is passed through the base material 2 by the first plating rod 3a in which the base material 2 is first hidden, and the base material 2 is applied by the second plating rod 3b in which the base material 2 is subsequently hidden. A process of forming a metal plating on the surface of the base material 2 is performed by passing a normal current.

  A through hole 39a is provided in the lower portion of the partition wall 39 of the plating basket 3, and the base material 2 is introduced into the first plating bowl 3a from one through hole 5a (the right side shown in FIG. 16) during plating. It is led out to the outside of the second plating rod 3b from the other through hole 5b (left side shown in FIG. 16) through the through hole 39a of the wall 39.

  When the silver plating 8 is formed on the base material 2 by the electroplating apparatus 1, an overcurrent is passed at the initial stage of the electroplating to form the silver plating 8. In this process, first, the base material 2 in an amount necessary for plating is introduced into the first plating rod 3a through the through hole 5a while being wound up in order. When a necessary amount of the base material 2 is set on the first plating rod 3a, the state is maintained, and an overcurrent flows between an electrode (not shown) immersed in the first plating rod 3a and the base material 2. . At this time, the current value of the overcurrent that flows through the base material 2 is set to a value that is, for example, 3 to 5 times the normal current value (that is, the current value that flows through the base material 2 by the second plating rod 3b). Has been. When an overcurrent is applied to the base material 2 by electroplating, the plating speed increases during the overcurrent application period, so that when the silver component adheres to the base material 2, it adheres to the base material 2 in a biased state. The silver plating 8 is formed on the base material 2 with a large uneven shape on the surface 8a.

  After passing the overcurrent for a predetermined time, the process of flowing the overcurrent to the base material 2 is stopped, and the portion plated with the first plating rod 3a is subsequently introduced into the second plating rod 3b through the through hole 39a. Is done. When the portion plated with the first plating rod 3a is set on the second plating rod 3b, the state is maintained, and between the electrode (not shown) immersed in the second plating rod 3b and the base material 2 A normal value current is passed through. When a current of normal value is passed through the base material 2 for a predetermined time, a silver component is newly stacked on the layer of silver plating 8 formed by passing an overcurrent, and finally the silver having the required layer thickness is stacked. A plating 8 is formed on the base material 2.

  When the silver plating 8 having the required layer thickness is formed, the process of supplying a normal current to the base material 2 is stopped, and the portion plated with the second plating rod 3b is subsequently passed through the through hole 5b. It leads out to the exterior of 2 plating cage | basket 3b. Then, the electroplating in which an overcurrent is passed in an initial stage and then a normal current is passed is repeatedly performed until the silver plating 8 is formed in all the portions of the base material 2 wound in a roll shape. The manufactured base material 2 is handled as the sample 11.

  By the way, when the silver plating 8 is formed at a normal current value in the electroplating, the silver plating 8 with the surface unevenness not so large is formed. However, in this example, an overcurrent is passed in the initial stage of electroplating, and the silver plating 8 having large surface irregularities is formed on the base material 2 in advance, and the silver component is attached thereto at a normal current value. Even when electroplating is performed at a low current value, since the silver component is previously stacked on the silver plating 8 having large unevenness, the surface of the finally formed silver plating 8 has a large uneven shape.

(Base material surface treatment)
FIG. 17 is a perspective view showing a working state when the surface 2a of the base material 2 is roughened. The method of enlarging the surface unevenness of the silver plating 8 is replaced with a method of flowing an overcurrent at the initial stage of electroplating, and a base material in which the surface 2a of the base material 2 is roughened in advance and the surface 2a is roughened. There is also a method of enlarging the surface unevenness of the silver plating 8 by electroplating 2. In order to roughen the surface 2a of the base material 2 in advance, for example, a file or shot blasting may be used. However, the method is not particularly limited as long as the surface unevenness of the base material 2 can be roughened.

  When electroplating is performed on the base material 2 having a rough surface 2a, the silver component in the plating solution 4 is sequentially stacked on the surface 2a of the base material 2 to form a layer of silver plating 8. Therefore, the silver plating 8 is the surface of the base material 2. It is formed in a shape along the shape. Therefore, if the unevenness of the surface 2a of the base material 2 is large, the silver plating 8 formed on the surface 2a of the base material 2 is also formed with a large surface unevenness.

(Etching-re-plating process)
FIG. 18 is an explanatory diagram when the sample 11 subjected to the silver plating 8 is etched. The method of enlarging the surface irregularities of the silver plating 8 is not limited to the method of flowing an overcurrent in the initial stage of electroplating or the method of roughening the surface 2a of the base material 2 in advance, but the sample 11 on which the silver plating 8 has been applied. It is also possible to etch the film and re-plat it. In this process, first, the silver plating 8 is formed on the base material 2 by electroplating with the above-described processing contents, and a sample 11 having the silver plating 8 on the surface layer is prepared.

  Then, as shown in FIG. 18, the sample 11 is immersed in an etching solution 41 in the etching trough 40, and the sample 11 is subjected to an etching process. At this time, since the surface 8a of the silver plating 8 is melted by the etching solution 41 and becomes rough, the surface 8a of the silver plating 8 changes from a state where the surface unevenness is not so large to a state where the surface unevenness becomes large.

  After the etching process, the sample 11 is again electroplated. That is, the etched sample 11 is set again in the electroplating apparatus 1, a direct current voltage is applied between the sample 11 and the electrode in the plating solution 4, and a silver component is laminated on the surface of the sample 11. To re-form the silver plating 8. The re-plating plating conditions (for example, the current value applied during plating) may be the same as or different from the initial electroplating.

  When the electroplating is again applied to the silver plating 8 having a large surface irregularity, the silver component in the plating solution 4 is sequentially stacked on the surface 8a of the silver plating 8 to form a laminated state. It is formed in a shape along the surface shape of the later silver plating 8. Therefore, in this example, since the silver plating 8 is re-plated on the surface of the silver plating 8 whose surface unevenness is roughened by etching, the surface layer of the final silver plating 8 is in a state where the surface unevenness is large.

According to the configuration of the second embodiment, in addition to the effects (3), (4), and (7) described in the first embodiment, the following effects can be obtained.
(8) A graphite rod 38 in which the graphite particles 10 are hardened is prepared, and the graphite particles 10 are adhered to the silver plating 8 by rubbing the graphite rod 38 against the silver plating 8, so that an appropriate amount of the graphite particles 10 can be easily applied. It can be fixed to the silver plating 8.

In addition, embodiment is not limited to the said structure, For example, you may change to the following aspects.
The sample 11 is not limited to a material obtained by simply applying the silver plating 8 to the base material 2, but may be a material in which the silver plating 8 containing the graphite particles 10 is formed on the base material 2 as shown in FIG. 19, for example. In order to manufacture the sample 11, first, graphite powder 10 having a particle diameter of, for example, about 1 to 20 μm is mixed in the plating solution 4. When a DC voltage is applied between the base material 2 and the electrode after the graphite is mixed, the silver plating 8 adheres to the base material 2. At this time, powdered graphite particles 10 are also taken in together with silver, as shown in FIG. The silver plating 8 contains graphite particles 10 in a dispersed state. In this case, the surface graphite area ratio S is further improved, and the wear resistance of the silver plating 8 is further improved.

The sample 11 is not limited to a material in which the silver plating 8 or graphite-containing silver plating is formed on the base material 2, but may be simply copper or nickel, for example.
-Fixing processing is not limited to high temperature processing or pressure processing. For example, a heat roll type in which the graphite particles 10 are fused to the sample 11 (silver plating 8) by heat and pressure, or the graphite particles 10 are fixed to the sample 11 (silver plating 8) by chemical change using a chemical solution. A chemical formula or the like may be adopted.

  -When metal plating is formed by electroplating, the metal plating is not limited to silver plating 8, but for example, gold plating, electroless nickel plating, chrome plating, nickel plating, solder plating, tin plating, zinc plating, etc. may be adopted. Good.

The plating method of the base material 2 is not limited to electroplating, and for example, chemical plating, hot dipping, physical vapor deposition, chemical vapor deposition, permeation plating, etc. may be employed.
The electric contact material manufacturing apparatus 9 is not limited to the drum type in which the photosensitive drum 13 rotates around the center point O, and may be, for example, a belt type in which a belt-shaped photosensitive belt member connected to one rotates.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(1) A photoreceptor that can rotate around a center point, a charging mechanism that charges the photoreceptor, an exposure mechanism that forms an electrostatic latent image on the surface of the photoreceptor by the amount of light that is exposed to the photoreceptor, and an electric charge A developing mechanism that develops the graphite particles imparted to the photoconductor, and a reverse charge applied from the back side of the metal body when the metal body that is the transfer destination of the graphite particles is transported. An electrical contact material manufacturing apparatus comprising: a transfer mechanism for transferring the graphite particles to the metal body; and a fixing mechanism for fixing the graphite particles transferred to the metal body to the surface of the metal body. .

The schematic block diagram which shows schematic structure of the electroplating apparatus in 1st Embodiment. Sectional drawing of the sample by which silver plating was formed on the surface. The schematic block diagram which shows schematic structure of an electrical contact material manufacturing apparatus. Explanatory drawing when charging a photosensitive drum. Explanatory drawing at the time of exposing the photosensitive drum after charging. Explanatory drawing at the time of developing a graphite particle on the photosensitive drum after exposure. Explanatory drawing at the time of transferring the graphite particle developed on the photosensitive drum to a sample. (A) is sectional drawing of the sample at the time of covering graphite powder to silver plating, (b) is sectional drawing of the sample after fixing graphite particle | grains to silver plating. The graph which shows the relationship between the surface graphite area ratio and its durability. The schematic block diagram which shows schematic structure of a laser apparatus. The schematic block diagram which shows schematic structure of a furnace apparatus. The schematic block diagram which shows schematic structure of a pressure processing apparatus. Sectional drawing of the graphite particle by which the resin film was coated on the surface. Explanatory drawing of the graphite particle fixing method in 2nd Embodiment. Sectional drawing of the electrical contact material after fixing graphite to silver plating. The schematic block diagram which shows schematic structure of the electroplating apparatus of another structure. The perspective view which shows the working state at the time of roughening the surface of a base material. Explanatory drawing at the time of etching the sample which gave silver plating. Sectional drawing of the sample to which the silver plating containing graphite was given.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Base material, 8 ... Silver plating as metal plating, 10 ... Graphite particle, 11 ... Sample as metal body, 12 ... Electrical contact material, 13 ... Photosensitive drum as photoconductor, 20 ... Electrostatic latent image, 37 ... insulating film, 38 ... graphite rod as bar, O ... center.

Claims (8)

Charging the rotatable photoreceptor around the center point; and
A procedure of forming an electrostatic latent image on the surface of the photoconductor by the amount of light exposed to the photoconductor;
A procedure for developing graphite particles imparted with electric charge to the photoreceptor on which the electrostatic latent image has been formed;
A procedure of transferring the graphite particles developed on the photoconductor to the metal body by applying a reverse charge from the back side of the metal body when transporting the metal body as a transfer destination of the graphite particles;
And a method of fixing the graphite particles transferred to the metal body on the surface of the metal body.   The method for producing an electrical contact material according to claim 1, wherein the procedure for fixing the graphite particles to the metal body is a procedure for subjecting the metal body to a high temperature treatment to melt the surface of the metal body. .   2. The electricity according to claim 1, wherein the procedure of fixing the graphite particles to the metal body is a procedure of plastically deforming the surface of the metal body by applying a pressure treatment to the surface of the metal body. Contact material manufacturing method.   The electrical contact material manufacturing method according to claim 1, wherein the graphite particles are coated with an insulating film made of a resin.   5. The metal body is formed by forming a graphite-containing metal plating on a part of or the entire surface of a base material, and the graphite is transferred to the surface of the metal plating. The electrical contact material manufacturing method as described in any one of them.   Forming metal plating on a part or the entire surface of the base material, and rubbing a bar material in which graphite is hardened to a rough portion of the surface of the metal plating, thereby fixing the graphite to the surface of the metal plating. A method for producing an electrical contact material characterized by the above.   An electrostatic latent image is formed on the surface of the photoconductive drum by charging the photoconductive drum rotatable around the support shaft, and the photoconductive drum is formed on the surface of the photoconductive drum. The graphite particles developed on the photosensitive drum are developed by developing a charged graphite particle and applying a reverse charge from the back side of the metal body when transporting the metal body to which the graphite particles are transferred. An electrical contact material produced by transferring particles to the metal body and fixing the graphite particles transferred to the metal body on the surface of the metal body.   By forming a metal plating on a part of or the entire surface of the base material and rubbing a bar material in which graphite is hardened against a rough portion of the surface of the metal plating, the graphite is fixed on the surface of the metal plating. Manufactured electrical contact material.

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