JP2009063817A - Conductive roller and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive roller having flexibility and an excellent surface state in combination as a whole and to provide a manufacturing method for the same. <P>SOLUTION: This invention relates to the manufacturing method for the conductive roller having a lamination structure including a conductive sponge layer 2 arranged outside a shaft 1, a conductive solid layer 4 arranged outside the conductive sponge layer 2 and a coating film 5 formed on a surface of the conductive solid layer 4, wherein the shaft 1 is fitted into the conductive sponge layer 2, and a dummy shaft 10 force-fitted into the cylindrical conductive solid layer 4, and after that, the dummy shaft 10 is removed to form the cylindrical solid layer 4, and the conductive sponge layer 2 fitted with the shaft 1 is force-fitted into the cylindrical conductive solid layer 4, and the coating film 5 is formed on the conductive solid layer 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a conductive roller used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine, and a conductive roller manufactured thereby.

  In recent years, characteristics required for conductive rollers used in image forming apparatuses such as electrophotographic apparatuses have been increasing.

  Corona discharge has generally been used as a charging method in a charging device. Corona discharge requires a high applied voltage in order to obtain a desired charge amount, which not only increases the size of the charging device but also generates a large amount of ozone, which poses a problem for environmental health. As a measure for this problem, a so-called contact charging method in which charging is performed by bringing a roller-shaped voltage application member into contact with a photosensitive member has been used in recent years. Since the contact type charging roller can be charged with a lower applied voltage than the corona discharge type, it has an advantage that the amount of ozone generated is extremely small.

  Similarly, in the transfer device, the toner is moved from the photosensitive member, the transfer belt directly or via the transfer belt to the printing paper or the like by using a transfer roller and applying voltage without using corona discharge. A contact transfer method has been proposed.

  On the other hand, in developing devices, a system in which a photoreceptor and a developing roller are arranged so as to contact each other has been used in recent years.

  The charging, transfer, and developing rollers, which are conductive rollers of these contact types, require a predetermined electric resistance value, and ensure uniform contact with the surface of the photosensitive member and the transfer belt in order to stabilize the electric resistance value. Therefore, flexibility (low hardness) is required so as to have a wide nip width. Furthermore, flexibility is required to suppress vibration noise generated by charging, transfer, and vibration between the developing roller and the photosensitive member or transfer belt.

  As a means for flexibility having such a predetermined resistance value, examples of blending a large amount of softeners and plasticizers, examples using a foaming agent, and the like have been proposed and used suitably. .

For example, in Cited Document 1, although the roller uses a foam, the electrical resistance is stable, and even if the contact width required for fixing between the photosensitive member and the shaft is taken, rotation unevenness and damage to the drive gear are caused. In addition, a developing roller having a surface roughness necessary for carrying toner is disclosed.
JP 2001-132858 A

  As the speed and image quality of the image forming apparatus progresses, the above-described conductive roller is required to have not only a predetermined resistance value and flexibility, but also a good surface property (toner releasability). In the above example, it cannot be said that the surface state is good with respect to toner releasability and the like.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a conductive roller having both flexibility as a whole and an excellent surface state, and a method for manufacturing the same. .

  The present invention relates to a laminated structure including a conductive sponge layer disposed outside a shaft, a conductive solid layer disposed outside the conductive sponge layer, and a coating film formed on the surface of the conductive solid layer. A method of manufacturing a conductive roller, wherein a cylindrical shaft is formed by fitting a shaft into a cylindrical conductive sponge layer, pressing the dummy shaft into the cylindrical conductive solid layer, and then removing the dummy shaft. The present invention relates to a method for manufacturing a conductive roller in which a conductive solid layer is formed, a conductive sponge layer fitted with a shaft is press-fitted into a cylindrical conductive solid layer, and a coating film is formed on the surface of the conductive solid layer.

  Moreover, in the manufacturing method of the electroconductive roller of this invention, it is preferable to grind | polish the surface of the electroconductive sponge layer which fitted the shaft.

  Moreover, in the manufacturing method of the electroconductive roller of this invention, it is preferable to grind the outer surface of the electroconductive solid layer which fitted the dummy shaft.

  Moreover, in the manufacturing method of the electroconductive roller of this invention, it is preferable to apply | coat an adhesive agent to the inner surface of a cylindrical electroconductive solid layer.

  In the method for producing a conductive roller of the present invention, the outer diameter of the conductive sponge layer fitted with the shaft is preferably 0.1 to 10% larger than the inner diameter of the cylindrical conductive solid layer. .

In the method for producing a conductive roller of the present invention, the conductive sponge layer has a volume resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω, and the conductive solid layer has a surface resistance value of 1 × 10 ^2. It is preferably ˜1 × 10 ⁹ Ω and the thickness is preferably 0.1 to 2 mm.

The present invention also relates to a conductive roller having a laminated structure in which a conductive sponge layer covering the shaft, a conductive solid layer covering the conductive sponge layer, and a coating film covering the conductive solid layer are stacked. The conductive sponge layer has a volume resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω, and the conductive solid layer has a surface resistance value of 1 × 10 ² to 1 × 10 ⁹ Ω. The present invention relates to a conductive roller that is 0.1 mm to 2 mm and includes an adhesive layer between a conductive sponge layer and a conductive solid layer.

  The method for producing a conductive roller of the present invention can produce a conductive roller using a conductive solid layer having flexibility as a whole and an excellent surface state.

  Moreover, since the manufacturing method of the conductive roller of the present invention is performed before the outer surface of the conductive solid layer is polished before becoming a product as a conductive roller, the accuracy of the outer diameter of the conductive roller is further enhanced. Can be.

  In addition, since the conductive roller of the present invention has an adhesive layer between the conductive sponge layer and the conductive solid layer, there is an affinity between the material of the conductive sponge layer and the material of the conductive solid layer. Even in a low case, unlike the conventional case, the conductive sponge layer and the conductive solid layer can be bonded. In addition, during the operation of the conductive roller, the conductive solid layer can be prevented from floating from the conductive sponge layer, and the conductive solid layer can be prevented from peeling off from the conductive sponge layer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, dimensional relationships such as length, size, and width in the drawings are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensions.

<Method for producing conductive roller>
Hereinafter, the manufacturing method of the conductive roller in the present invention will be described by taking the manufacturing method of the transfer roller as an example.

  FIG. 1A is a side view of a transfer roller as an embodiment of the conductive roller of the present invention, and FIG. 1B is a front view of the transfer roller. FIG. 2 is a flowchart of the transfer roller manufacturing method. FIG. 3 is a schematic diagram showing each manufacturing process of the transfer roller manufacturing method. Hereinafter, description will be made based on FIGS. 1, 2, and 3.

  First, the structure of a transfer roller manufactured as an embodiment of the present invention will be briefly described. As shown in FIG. 1, the transfer roller includes a conductive sponge layer 2 disposed outside the shaft 1, a conductive solid layer 4 disposed outside the conductive sponge layer 2, and a conductive solid layer 4. A laminated structure including the coating film 5 formed on the surface is provided as a basic form. An adhesive layer 3 is formed between the conductive sponge layer 2 and the conductive solid layer 4.

  The thicknesses of the conductive sponge layer 2, the conductive solid layer 4, and the coating film 5 in the transfer roller are within a predetermined allowable range.

  Next, based on FIG. 2 and FIG. 3, the outline of the manufacturing method of this transfer roller is demonstrated. In FIG. 2, the steps in parentheses can be omitted.

  In the manufacturing method of the present embodiment, the conductive sponge layer 2 fitted with the shaft 1 and the cylindrical conductive solid layer 4 are produced. Then, the transfer sponge is completed by press-fitting the conductive sponge layer 2 fitted with the shaft 1 into the cylindrical conductive solid layer 4 to form the coating film 5 on the surface of the conductive solid layer 4. To do. Hereinafter, the details of the production method of the present invention will be described.

≪Production of conductive sponge layer fitted with shaft≫
The conductive sponge layer 2 fitted with the shaft 1 as shown in FIG. 3D is manufactured by press-fitting the shaft 1 into the cylindrical conductive sponge layer 2. Further, as necessary, as shown in FIG. 3 (e), the surface of the conductive sponge layer 2 on which the shaft 1 is appropriately fitted is polished.

  First, the material of the conductive sponge layer 2 is kneaded and then formed into an elongated cylindrical shape as shown in FIG. 3A by extrusion molding, injection molding, press molding or the like by a conventional method. When the material is kneaded, a chemical foaming agent is added. Then, as shown in FIG. 2, the formed material is heated and vulcanized. The vulcanization may be performed separately from the primary vulcanization and the secondary vulcanization. After the vulcanization, a cylindrical conductive sponge layer 2 is prepared by cutting to a desired length as shown in FIG. The cylindrical conductive sponge layer 2 refers to a layer having a circular cross section perpendicular to the longitudinal direction and hollow. In the present invention, a known apparatus can be used in extrusion molding, injection molding, or press molding.

  As the material for the cylindrical conductive sponge layer 2, a polymer material having conductivity can be used. Specifically, the material of the conductive sponge layer 2 is a polymer composition having conductivity by mixing carbon rubber or metal powder into a conductive rubber, thermoplastic elastomer or thermoplastic resin. Foam can be used.

Further, the conductivity of the conductive sponge layer 2 in the transfer roller is preferably adjusted as appropriate so that the volume resistance value of the transfer roller produced by this manufacturing method is 1 × 10 ⁴ Ω to 1 × 10 ⁹ Ω. . FIG. 4 is a schematic diagram for explaining the measuring method of the volume resistance value in the present invention. The conductive roller 32 is pressed into contact with a metal roll 31 having a diameter of 30 mm at both ends of 0.5 kg and a total of 1.0 kg, and the resistance roll 33 is a resistance value measuring machine (manufactured by Trek) while rotating the metal roll 31. The volume resistance value can be calculated by applying a voltage of 1000 V to the metal roll 31 and reading the current value after 5 seconds.

  The cylindrical conductive sponge layer 2 is foamed rubber in this embodiment. Foam rubber refers to rubber having a small apparent density and containing a plurality of bubbles inside. The conductive sponge layer 2 of the present invention may have closed cells or open cells.

  Then, the prepared shaft 1 is press-fitted into the cylindrical conductive sponge layer 2 as shown in FIG. At this time, as shown in FIG. 1A, when viewed from the side, the shaft 1 and the cylindrical conductive sponge layer 2 are parallel so that the shaft 1 is at the center of the conductive sponge layer 2. Press fit. The conductive sponge layer 2 expands when the shaft 1 is press-fitted. When the conductive sponge layer 2 is stretched, the conductive sponge layer 2 is brought into close contact with the shaft 1 by a force for contraction, which is the opposite force. If necessary, the shaft 1 and the sponge layer 2 may be bonded. In this way, the conductive sponge layer 2 is fixed so as to be disposed outside the shaft 1. And the conductive sponge layer 2 which fitted the shaft 1 as shown in FIG.3 (d) is formed.

  Further, as shown in FIG. 3E, the surface of the conductive sponge layer 2 on which the shaft 1 is fitted is polished. However, if the surface is within a predetermined accuracy, it may not be polished. The polishing is performed in order to appropriately align the dimensions. Polishing can be performed by a known method.

<< Production of cylindrical conductive solid layer >>
The cylindrical conductive solid layer 4 is formed by press-fitting a dummy shaft into the cylindrical conductive solid layer 4 to produce the conductive solid layer 4 fitted with the dummy shaft, and the dummy shaft is removed from the conductive solid layer 4. It is made by removing.

  First, the material of the conductive solid layer 4 is kneaded and then formed into an elongated cylindrical shape as shown in FIG. 3F by extrusion molding, injection molding, press molding or the like by a conventional method. Then, as shown in FIG. 2, the formed material is heated and vulcanized. The vulcanization may be performed separately from the primary vulcanization and the secondary vulcanization. After the vulcanization, a cylindrical conductive sponge layer 2 is prepared by cutting to a desired length as shown in FIG. The cylindrical conductive solid layer 4 refers to a layer whose cross section perpendicular to the longitudinal direction is circular and hollow.

As a material for the cylindrical conductive solid layer 4, a polymer material having conductivity can be used. Specifically, the material of the conductive solid layer 4 is made of a conductive rubber, or a polymer composition having conductivity by mixing carbon black or metal powder into a thermoplastic elastomer or thermoplastic resin. Can be used. The material of the conductive sponge layer 2 and the material of the conductive solid layer 4 described above may be different. Further, the conductive solid layer 4 is appropriately adjusted so that the surface resistance value in the transfer roller produced by this production method is 1 × 10 ² to 1 × 10 ⁹ Ω and the thickness is 0.1 to ² mm. It is preferable. FIG. 5 is a schematic diagram for explaining a method for measuring a surface resistance value in the present invention. The conductive roller 32 is installed on the metal shaft 41 by its own weight, and a voltage of 1000 V is applied to the metal shaft 41 on which the conductive roller 32 is installed by a resistance value measuring machine (R8340: manufactured by Advantest Co., Ltd.). The resistance value after 5 seconds is set as the surface resistance value.

  Then, the dummy shaft 10 prepared as shown in FIG. 3H is press-fitted into the cylindrical conductive solid layer 4. At this time, as shown in FIG. 1A, when viewed from the side, the dummy shaft 10 and the cylindrical conductive solid layer 4 are parallel so that the dummy shaft 10 is at the center of the conductive solid layer 4. Press fit. The conductive solid layer 4 is made of a shrinkable material, and the conductive solid layer 4 expands when the dummy shaft 10 is press-fitted. The conductive solid layer 4 has an inner diameter that is substantially the same as the outer diameter of the dummy shaft 10. As described above, the conductive solid layer 4 fitted with the dummy shaft 10 as shown in FIG. 3I is formed.

  Next, as shown in FIG. 3J, the surface of the conductive solid layer 4 fitted with the dummy shaft 10 is polished as appropriate. The polishing is performed to make the thickness uniform and smooth the surface. Polishing can be performed by a known method. However, it is not necessary to polish what is in a predetermined accuracy and surface state.

  Then, as shown in FIG. 3 (k), the dummy shaft 10 is removed from the conductive solid layer 4 on which the dummy shaft 10 is fitted. When removing, for example, the dummy shaft 10 may be pulled out from the conductive solid layer 4. Thereby, the cylindrical conductive solid layer 4 is formed. Here, what is obtained by removing the dummy shaft 10 from the cylindrical conductive solid layer 4 is referred to as “cylindrical conductive solid layer 4” in the present specification.

  And as shown in FIG.3 (l), the adhesive agent 20 used as the adhesive bond layer 3 is apply | coated to the inner surface of this cylindrical conductive solid layer 4. As shown in FIG. Even when the affinity between the material of the conductive sponge layer 2 and the material of the conductive solid layer 4 is low by applying the adhesive 20, unlike the conventional case, the conductive sponge layer 2 and the conductive solid layer 4. Can be glued together. Further, it is possible to prevent the conductive solid layer 4 from floating from the conductive sponge layer 2 and the conductive solid layer 4 from being peeled off from the conductive sponge layer 2 during the operation of the conductive roller. is there. The adhesive 20 is preferably a conductive material.

≪Finish of transfer roller≫
As shown in FIG. 3 (m), the conductive sponge layer 2 fitted with the shaft 1 is press-fitted into the cylindrical conductive solid layer 4 produced by the above-described operation. At this time, the outer diameter of the conductive sponge layer 2 fitted with the shaft 1 is preferably 0.1 to 10% larger than the inner diameter of the cylindrical conductive solid layer 4.

  Further, since the adhesive 20 is applied to the inner surface of the cylindrical conductive solid layer 4, the conductive solid layer 4 and the conductive sponge layer 2 are bonded by heating after press-fitting. The conductive sponge layer 4 fitted with the conductive solid layer 2 fitted with the shaft 1 as shown in FIG.

  Finally, as shown in FIG. 3 (o), a coating film 5 is formed on the surface of the conductive solid layer 4. The coating film 5 can be formed by applying a conductive paint on the surface. Examples of the conductive paint include those obtained by adding a conductive filler to a mixed resin of isoprene-based resin and fluorine-based resin.

The transfer roller is manufactured through the above steps.
In the manufacturing method of this embodiment, the process of grind | polishing the outer surface of the electroconductive solid layer 4 which fitted the dummy shaft 10 can be provided. This step is a step for forming an excellent surface state in the transfer roller, and can be performed more simply than the conventional step of adjusting the surface state. Moreover, the transfer roller using the preferable electroconductive solid layer 4 can be provided.

  The transfer roller manufacturing method according to the present embodiment can produce a transfer roller having flexibility as a whole and an excellent surface state.

<Conductive roller>
A transfer roller as an embodiment of the conductive roller of the present invention will be described below with reference to FIG. The structure of the transfer roller is as described above.

In the transfer roller, the conductive sponge layer 2 has a volume resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω, and the conductive solid layer 4 has a surface resistance value of 1 × 10 ² to 1 × 10 ^9. The thickness is 0.1 mm to 2 mm, and the adhesive layer 3 is provided between the conductive sponge layer 2 and the conductive solid layer 4.

  As the materials for the conductive sponge layer 2, the conductive solid layer 4, and the coating film 5, the same materials as described above can be used as appropriate.

  The conductive sponge layer 2 and the conductive solid layer 4 are bonded via an adhesive layer 3. Therefore, the conductive sponge layer 2 and the conductive solid layer 4 are not integrated by melting each other, and the conductive sponge layer 2 and the conductive solid layer 4 are in contact with the adhesive layer 3. Yes. Even if the affinity between the material of the conductive sponge layer 2 and the material of the conductive solid layer 4 is low due to this structure, the conductive sponge layer 2 and the conductive solid layer 4 can be bonded unlike the conventional case. it can. Further, during the operation of the conductive roller, the conductive solid layer 4 can be prevented from floating from the conductive sponge layer, and the conductive solid layer 4 can be prevented from peeling off from the conductive sponge layer 2.

  In the above embodiment, the transfer roller has been described, but it goes without saying that it can also be applied to a charging roller and a developing roller.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

(A) is a side view of the transfer roller which is one Embodiment of this invention, (b) is a front view of this transfer roller. It is a figure which shows the flowchart of the manufacturing method of the transfer roller which is one Embodiment of this invention. It is a schematic diagram which shows each manufacturing process of the manufacturing method of the transfer roller which is one Embodiment of this invention. It is a schematic diagram explaining the measuring method of the volume resistance value in this invention. It is a schematic diagram explaining the measuring method of the surface resistance value in this invention.

Explanation of symbols

  1 shaft, 2 conductive sponge layer, 3 adhesive layer, 4 conductive solid layer, 5 coating film, 10 dummy shaft, 20 adhesive, 31 metal roll, 32 conductive roller, 33 resistance meter, 41 metal shaft.

Claims (7)

A laminated structure including a conductive sponge layer disposed outside the shaft, a conductive solid layer disposed outside the conductive sponge layer, and a coating film formed on a surface of the conductive solid layer. A method for producing a conductive roller, comprising:
The shaft is fitted into the cylindrical conductive sponge layer,
After pressing the dummy shaft into the cylindrical conductive solid layer, forming the cylindrical conductive solid layer formed by removing the dummy shaft,
The conductive sponge layer fitted with the shaft is press-fitted into the cylindrical conductive solid layer,
The manufacturing method of the electroconductive roller which formed the said coating film on the surface of the said electroconductive solid layer.   The method for producing a conductive roller according to claim 1, wherein a surface of the conductive sponge layer on which the shaft is fitted is polished.   The method for manufacturing a conductive roller according to claim 1 or 2, wherein an outer surface of the conductive solid layer into which the dummy shaft is press-fitted is polished.   The manufacturing method of the electroconductive roller in any one of Claims 1-3 which apply | coats an adhesive agent to the inner surface of the cylindrical said electroconductive solid layer.   5. The conductivity according to claim 1, wherein an outer diameter of the conductive sponge layer fitted with the shaft is 0.1 to 10% larger than an inner diameter of the cylindrical conductive solid layer. Roller manufacturing method. The conductive sponge layer has a volume resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω,
6. The conductive roller according to claim 1, wherein the conductive solid layer has a surface resistance value of 1 × 10 ² to 1 × 10 ⁹ Ω and a thickness of 0.1 to ² mm. Method. A conductive roller having a laminated structure in which a conductive sponge layer covering the shaft, a conductive solid layer covering the conductive sponge layer, and a coating film covering the conductive solid layer are laminated,
The conductive sponge layer has a volume resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω,
The conductive solid layer has a surface resistance value of 1 × 10 ² to 1 × 10 ⁹ Ω and a thickness of 0.1 mm to ² mm.
A conductive roller comprising an adhesive layer between the conductive sponge layer and the conductive solid layer.

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