JP2006168125A - Rubber roller and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a rubber roller which is excellent in the adhesiveness to the contact surface of the rubber roller constituted by providing an elastomer layer comprising a rubber composition on the outer periphery of a core metal, constituted so as to obtain uniform electrical characteristics on the surface of the elastomer layer regardless of a place, has excellent durability, made more simple, conserved in space and low in cost, and the rubber roller obtained by this manufacturing method. <P>SOLUTION: The manufacturing method of the rubber roller, which has at least one elastomer layer comprising a rubber composition bonded on the outer periphery of its core metal, has a process for applying an adhesive to the core metal preheated to 100-200°C and a process for bonding the core metal and the rubber composition. The rubber roller obtained by this manufacturing method is also disclosed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber roller and a manufacturing method thereof, and more particularly to a manufacturing method of a rubber roller such as a charging roller and a transfer roller used in an image forming apparatus such as electrophotography, and a rubber roller obtained by the method.

  Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, the surface of an electrophotographic photosensitive member is uniformly charged, and an image is projected onto the electrophotographic photosensitive member from an optical system, and a portion exposed to light. A latent image is formed by erasing the charge of the toner, and then printing is performed by forming (developing) a toner image by adhesion of toner and transferring the toner image onto a recording medium such as transfer paper. Various conductive rollers are used as such charging members and transfer members.

  Examples of such a conductive rubber composition for a conductive rubber roller include a conductive rubber composition in which a conductive filler such as conductive carbon black is dispersed in a rubber component such as EPDM, and a more uniform electric resistance. In order to obtain a conductive rubber roller having a conductive rubber composition, a conductive rubber composition using a rubber component having a low electrical resistance to some extent (for example, epichlorohydrin rubber or NBR) is known.

  By the way, when manufacturing these conductive rubber rollers, the following methods are known. An unvulcanized conductive rubber composition is formed into a tube shape with an extruder, vulcanized with a steam vulcanizer, hot-air oven, microwave vulcanizer, etc., and an adhesive is applied to the resulting conductive rubber tube. A method of obtaining a target roller by a tube press-fitting method by press-fitting the coated metal core, or by extruding the unvulcanized rubber composition using an extruder for cost reduction. After passing the conductive shaft through the crosshead die of the extruder, placing the unvulcanized conductive rubber composition on the outer periphery of the core metal coated with adhesive, and forming a roller shape, through the vulcanization process Methods for manufacturing are known.

  Furthermore, since uniform charging and uniform transfer are required, the conductive rubber roller needs to reduce resistance unevenness, and the conductive elastic layer is required to have roller shape accuracy. Therefore, a method is known in which a desired accuracy is obtained by polishing the rubber composition layer of a conductive rubber roller with a cylindrical grinder.

  However, depending on the material of these rubber rollers, in an environment of high temperature and high humidity, the elastic layer expands and floats up from the metal core, resulting in poor adhesion, or chatter due to stress during polishing due to insufficient adhesion. This is a cause of image defects.

Then, in order to solve the above problems, a method is known in which an adhesive is applied to the outer periphery of the core bar and then used after being baked (see, for example, Patent Document 1). However, if the method is used after baking, the baking temperature condition is limited due to the heat resistance of the adhesive, and the baking time becomes long because the temperature is raised from room temperature. In addition, it is necessary to prevent the metal cores from touching each other during the baking process. Further, even if the baking time is too long, the adhesive is deteriorated and the adhesive strength is lowered. Therefore, it is necessary to manage time and temperature for each one. Therefore, it is disadvantageous in the manufacturing process.
Japanese Patent Laid-Open No. 10-293440

  The object of the present invention has been made in the background of such circumstances, and the problem to be solved is the contact surface of a rubber roller in which an elastic body layer made of a rubber composition is provided on the outer periphery of a core metal. It is a rubber roller manufacturing method that has excellent adhesiveness and has uniform electrical characteristics regardless of location on the surface of the elastic layer, and has excellent durability, and more easily, space-saving and low-cost manufacturing method of the rubber roller And providing a rubber roller obtained by the method.

  According to the present invention, there is provided a method for producing a rubber roller having an elastic layer made of at least one rubber composition bonded on the outer periphery of a core metal, the adhesive being applied to the core metal preheated at 100 ° C. to 200 ° C. There is provided a method for producing a rubber roller, comprising the steps of: applying a core and a step of adhering the core metal and the rubber composition.

  Further, according to the present invention, there is provided a rubber roller used in an image forming apparatus, which is obtained by the above-described method for manufacturing a rubber roller.

  As apparent from the above description, according to the present invention, when the adhesive is applied on the outer periphery of the core metal, the core metal temperature is set to 100 ° C. to 200 ° C. After applying the adhesive to the core, before placing the unvulcanized conductive rubber composition on the outer periphery of the core metal to form a roller shape, the process of heating the core metal coated with the adhesive on the outer periphery is omitted. Excellent adhesion between the elastic body layer of the rubber roller and the cored bar provided with an elastic body layer made of a rubber composition on the outer periphery of the gold, and uniform electrical characteristics can be obtained regardless of the location in the elastic body layer. It was a rubber roller manufacturing method with excellent durability, and a simple, space-saving and low cost rubber roller manufacturing method could be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  The method for producing a rubber roller according to the present invention is a method for producing a rubber roller having an elastic body layer composed of at least one rubber composition bonded on the outer periphery on the outer periphery of the core metal, and preheating at 100 ° C. to 200 ° C. A method of manufacturing a rubber roller, comprising: applying an adhesive to the cored bar, and bonding the cored bar and the rubber composition.

  That is, a major feature of the present invention is that the baking process is omitted by preheating the core metal at 100 ° C. to 200 ° C. before applying the adhesive to the core metal. If the core temperature is less than 100 ° C, adhesive peeling or chattering will occur as in the case of no preheating, and if it exceeds 200 ° C, the adhesive will deteriorate, resulting in lower adhesion. To do. The temperature of the core before application of the adhesive is preferably 100 ° C to 170 ° C, more preferably 110 ° C to 130 ° C. The temperature of the core metal may be within the above range, and the heating time is arbitrary.

  The rubber composition of the elastic layer of the rubber roller according to the present invention preferably contains epichlorohydrin rubber.

  At least epichlorohydrin-based rubber was added because of the addition of a conductive agent such as carbon black for resistance adjustment by including epichlorohydrin-based rubber known as a low-resistance rubber among various rubbers as described above. This is because a rubber having a more stable resistance can be obtained. However, epichlorohydrin rubber expands in an environment of high temperature and humidity, and the elastic layer is lifted from the core metal, resulting in poor adhesion, but this can be improved by the present invention.

  The adhesive used in the present invention preferably contains at least a lower alcohol or a ketone as a diluent solvent. Examples of lower alcohols include methanol and ethanol, and examples of ketones include methyl ethyl ketone and methyl isobutyl ketone.

  The adhesive that bonds the rubber composition and the metal core contains a synthetic resin, a filler for imparting conductivity, and the like. As a solvent suitable for dissolving or dispersing them, lower alcohols and the like Ketones are widely used. When such a solvent is used, a pseudo hydrogen bond is formed between the adhesive layer and the metal core. However, the ketones and lower alcohols in the adhesive solvent are easily compatible with water. It is believed that adhesion failure occurs at that portion, but the effect of preventing adhesion failure can be remarkably exhibited by preheating the cored bar of the present invention at 100 ° C. to 200 ° C. .

  In the present invention, the core metal coated with the adhesive is passed through the crosshead die, the unvulcanized rubber composition is extruded, the rubber composition is disposed on the outer periphery of the core metal, and then heated at 100 ° C. to 250 ° C. Thus, it is preferable to simultaneously perform vulcanization of the rubber composition and adhesion of the rubber composition to the metal core.

  There are various types of methods for forming the elastic layer of the rubber roller, and any method can be selected as long as it is suitable for satisfying the electrical characteristics and dimensional accuracy required for the member for the image forming apparatus. The rubber composition is extruded into a tube shape, and after vulcanization, the unvulcanized rubber composition is extruded using a method in which the rubber composition is press-fitted into a core metal or an extruder, and at the same time, the conductive shaft is continuously extruded from the extruder. There is a method in which an unvulcanized conductive rubber composition is placed on the outer periphery of a core metal coated with an adhesive by passing through a crosshead die to form a roller shape, and then manufactured through a vulcanization process. The latter is preferred for the production of rubber rollers because it is suitable for space saving and continuation of the production line. Various methods such as a steam vulcanization can and a hot stove are known as the vulcanization method, but the hot stove is preferable to the continuation rather than the steam vulcanization can.

  The rubber-metal adhesive used in the present invention is not particularly limited, and examples thereof include phenol-based, epoxy-based, polyolefin-based vulcanized adhesives, hot-melt adhesives, and the like. Preferred are vulcanized adhesives.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the examples, “part” means “part by mass”.

“Applying adhesive to the core”
N15 [Phenolic, manufactured by Toyo Chemical Laboratories Co., Ltd.] is diluted with an equal amount of methyl ethyl ketone, and Ty-ply BN (manufactured by Road Far East) is diluted with an equal amount of methyl ethyl ketone / methanol = 1/1, electroless nickel It was applied to a steel cored bar having a diameter of 6 mm and a length of 240 mm. In Examples 1, 2, and 3, preheating was performed until the core metal temperatures were 180 ° C., 150 ° C., and 120 ° C., respectively, and then the adhesive N15 was applied. In Examples 4, 5, and 6, the core metal temperatures were 180 ° C., respectively. After preheating up to 150 ° C., 150 ° C., and 120 ° C., an adhesive Ty-ply BN was applied.

  In Comparative Example 1, the adhesive N15 is applied to the core metal that has not been preheated. In Comparative Example 2, the adhesive Ty-ply BN is applied to the core metal that has not been preheated. In Comparative Example 3, the core metal is not preheated. Adhesive N15 was applied to the core metal and baked at 120 ° C. for 3 minutes in an electric furnace. In Comparative Example 4, adhesive N15 was applied to a core metal that was not preheated, and was then heated at 120 ° C. for 20 minutes in the electric furnace. I baked it. In Comparative Example 5, the adhesive N15 was applied after preheating until the core metal temperature reached 210 ° C., and in Comparative Example 6, the adhesive N15 was applied after preheating until the core metal temperature reached 90 ° C.

  Details of the adhesive used this time are shown in Table 1.

"Production of rubber composition"
Epichlorohydrin rubber [Brand name: Epichromer CG102, manufactured by Daiso Corporation] 100 parts Zinc oxide [Brand name: Zinc oxide type II, Hakusuitec Co., Ltd.] 5 parts Stearic acid [Brand name: Stearic acid S, Kao Corporation] 1 part Carbon Black [Brand name: Asahi # 15 Asahi Carbon Co., Ltd.] 5 parts Calcium carbonate [Brand name: Silver W Shiraishi Kogyo Co., Ltd.] 40 parts Dibenzothiazyl disulfide [Brand name: Noxeller DM Ouchi Shinsei Chemical Co., Ltd. ] 1 part Tetramethylthiuram monosulfide [trade name: Noxeller TS, manufactured by Ouchi Shinsei Chemical Co., Ltd.] 1 part sulfur [trade name: Sulfax 200S, manufactured by Tsurumi Chemical Co., Ltd.] 1 part of a closed kneader and an open roll machine An unvulcanized rubber composition was obtained by performing kneading using the rubber composition.

"Production of rubber roller"
Using an extruder, extrude the unvulcanized rubber composition prepared as described above and simultaneously preheat continuously, then pass the core metal coated with adhesive through the crosshead die continuously Thus, an unvulcanized rubber composition was disposed on the outer periphery of the core metal to form a roller shape. This was heated in a hot air oven at 180 ° C. for 1 hour to produce a rubber roller having an outer diameter of 12 mm having a vulcanized rubber layer. Further, a cutter blade was inserted at a position of 15 mm from both ends and the rubber layers at both ends were peeled off and then polished by a grinding machine to obtain a rubber roller having an outer diameter of 9 mm.

<Evaluation method>
Regarding the peeling of the elastic layer, the elastic layer of the roller left for 24 hours after polishing is cut in the longitudinal direction of the rubber roller with a cutter blade, and the elastic layer is peeled off from the cored bar at 10 locations per rubber roller with a pliers. The number of peels having a maximum diameter of 100 μm or more was visually observed at 10 times each with Video Micro 20 times, and rank evaluation was performed as follows:
◎: No peeling in 10 pieces ○: Less than 1 mm in 10 pieces peeled within 3 places △: Within 10 places, 1 mm or more and less than 3 mm pieces peeled out ×: 10 pieces in 3 pieces or more peeled or 100 μm or more There are countless rubber rollers

  With respect to chatter during polishing, 10 samples that were allowed to stand for 24 hours after polishing were each visually observed and ranked in the following manner.

◎: All 10 out of 10 have no chatter ○: There are 1-2 out of 10 chatter, but chatter is slight △: 3-5 out of 10 have chatter, but no chatter ×: 10 6 or more of them have chatter or one that has severe chatter

  Table 2 shows the evaluation results of Examples and Comparative Examples.

  In the method for producing a rubber roller having an elastic layer made of at least one rubber composition bonded on the outer periphery of the core metal according to Table 2, an adhesive is applied to the core metal preheated at 100 ° C. to 200 ° C. What was produced with the manufacturing method of the rubber roller which has a process and the process which adhere | attaches a metal core and this rubber composition has an effect in the chatter at the time of peeling of an elastic body layer and grinding | polishing.

  In Comparative Example 4, after applying the adhesive to the metal core, a baking process at 120 ° C. for 20 minutes was performed to suppress the elastic layer peeling and chatter during polishing. Since a process is required, it is disadvantageous in manufacturing cost and manufacturing space.

Claims (6)

  A process for producing a rubber roller having an elastic layer composed of at least one rubber composition bonded on the outer periphery of a core metal, the method comprising applying an adhesive to the core metal preheated at 100 ° C to 200 ° C And a step of adhering the cored bar and the rubber composition.   The method for producing a rubber roller according to claim 1, wherein the rubber composition contains epichlorohydrin rubber.   The method for producing a rubber roller according to claim 1 or 2, comprising at least a lower alcohol or a ketone as a diluent solvent for the adhesive.   The method for producing a rubber roller according to any one of claims 1 to 3, wherein the rubber composition is vulcanized on an outer periphery of a core metal coated with the adhesive.   By passing the core metal coated with the adhesive through a crosshead die and extruding an unvulcanized rubber composition, placing the rubber composition on the outer periphery of the core metal, and heating at 100 ° C. to 250 ° C. The method for producing a rubber roller according to any one of claims 1 to 4, wherein vulcanization of the rubber composition and adhesion of the rubber composition and the core metal are simultaneously performed.   A rubber roller used in an image forming apparatus, wherein the rubber roller is obtained by the method for producing a rubber roller according to claim 1.