JP2007108214A - Rubber roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber roller of high quality whose rubber layer is not apt to peel. <P>SOLUTION: The rubber roller has a columnar base material, having a plating film formed on its surface and the rubber layer formed on the plating film across an adhesive layer, and the adhesive layer is made thicker than the plating film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber roller, and in particular, it is used for a charging rubber roller, a developing rubber roller, a transfer rubber roller, a fixing rubber roller, a paper feeding rubber roller, etc. used in an electrophotographic copying machine or the like. It relates to rubber rollers.

  In an electrophotographic apparatus such as a laser printer or a facsimile, many rubber rollers such as a charging roller, a developing roller, and a transfer roller are used. These rubber rollers are generally configured to include a cylindrical base material that functions as a central axis, and a rubber layer formed on the outer peripheral surface of the cylindrical base material.

  The rubber layer of the rubber roller can be formed, for example, by coating an unvulcanized rubber composition on the outer peripheral surface of a cylindrical base material and performing a vulcanization treatment. However, since both ends of the rubber roller often expose the cylindrical base material so that it can be pivotally attached to the electrophotographic apparatus, it is generally unnecessary after forming a rubber layer on the entire outer peripheral surface of the cylindrical base material. A step of removing the rubber layer of the portion is performed.

  Since such a rubber roller is required to have a rust preventive effect for long-term use while maintaining very high dimensional accuracy, a method of forming a plating film on the surface of a cylindrical base material has been studied. For example, a method is known in which an electroless nickel plating film having a uniform plating film and a low processing cost is formed on the outer peripheral surface of a cylindrical base material (Patent Document 1).

However, since the electroless nickel plating film is rich in chemical activity, the cylindrical base material and the rubber layer are seized at the time of vulcanization treatment, and there is a problem that it is difficult to remove the rubber layer later. As a method for dealing with this problem, there is known a method for preventing seizure between a cylindrical base material and a rubber layer by subjecting an electroless nickel plating film to inactivation treatment such as chromic acid treatment or heat treatment (Patent Literature). 2).
Japanese Patent Publication No. 7-74057 Japanese Patent Publication No. 7-74056

  However, the method of Patent Document 2 has a problem that the rubber layer is easily peeled off because the adhesion between the cylindrical base material and the rubber layer in the obtained rubber roller is lowered.

  In addition, in the methods of Patent Documents 1 and 2, it is necessary to form a plating film by electroless nickel plating, and other plating methods such as electric nickel plating and zinc plating cannot be used, and a plating film according to the application is formed. Can not do it.

  Furthermore, in the methods of Patent Documents 1 and 2, the rubber layer is formed directly without using the adhesive layer, but the adhesion between the cylindrical base material and the rubber layer is higher than when using the adhesive layer. It is low, and the rubber layer may be peeled off depending on the application and use conditions. In the first place, even in the rubber roller in which the rubber layer is formed on the cylindrical base material via the adhesive layer, the adhesiveness between the adhesive layer and the cylindrical base material is not sufficient, and the adhesive layer adhered to the rubber layer, At present, there is a problem of peeling between the cylindrical base material.

  When peeling as described above occurs, for example, when the surface of the rubber layer of the rubber roller after production is ground, the rubber layer becomes idle, resulting in a problem that the dimensional accuracy of the rubber roller is deteriorated. In addition, when a fluororesin tube is formed as a release layer on a rubber layer like a charging roller, there is a problem that the fluororesin tube cannot be formed because the rubber layer is turned over. In addition, when used as a roller that is driven from the outside, such as a developing roller, a toner supply roller, a charging roller, etc., and the surface of which is subjected to torque by friction or pressure contact (hereinafter also referred to as a driving roller), the rubber layer becomes idle. As a result, there is a problem that the performance of the electrophotographic apparatus is adversely affected.

  Accordingly, an object of the present invention is to provide a high-quality rubber roller in which the rubber layer is difficult to peel off, with respect to such problems of the prior art.

  The present invention that achieves the above object provides a rubber roller having a cylindrical base material having a plating film formed on a surface thereof, and a rubber layer formed on the plating film via an adhesive layer. The rubber roller has a thickness equal to or greater than the thickness of the plating film.

  ADVANTAGE OF THE INVENTION According to this invention, a high quality rubber roller with which a rubber layer cannot peel easily can be provided.

  Hereinafter, the present invention will be described in detail.

  The cylindrical base material used for the rubber roller of the present invention may be hollow or solid. The material of the cylindrical base material is not particularly limited, and conventionally known materials can be used as a cylindrical base material for manufacturing rubber rollers such as iron and steel. The magnitude | size of a cylindrical base material can be suitably selected according to the application site | part of a rubber roller, for example, the cylindrical base material of diameter 4-50mm and length 50-400mm can be used.

  The cylindrical base material used for the rubber roller of the present invention has a plating film formed on the surface thereof. The type of plating is not particularly limited as long as it satisfies the function of the rubber roller. For example, inexpensive electroless nickel plating may be used, and electro nickel plating or zinc plating may be used. That is, it can be adapted to conventionally known plating necessary for the function of the cylindrical substrate.

  The thickness of the plating film can be selected as appropriate so that the required rust prevention effect is exhibited. For example, a plating film of 1 to 10 μm can be formed.

  In the rubber roller of the present invention, a rubber layer is formed on the plating film on the surface of the cylindrical base material via an adhesive layer. The adhesive layer may be formed on the entire plating film. However, when the rubber layer is removed later, it is preferable that the adhesive layer is formed only at a portion where the rubber layer is finally formed.

  As the adhesive forming the adhesive layer, a conventionally known adhesive having good adhesion to the rubber layer may be used. For example, a vulcanized adhesive, a hot melt adhesive, or the like can be used.

  The thickness of the adhesive layer needs to be selected so as to be equal to or greater than the thickness of the plating film. This is based on the finding that the pinhole existing in the plating film is the cause as a result of analyzing the mechanism by which the rubber layer of the rubber roller is peeled off.

  In general, before forming a plating film on a cylindrical base material, so-called plating pretreatment such as alkaline degreasing and acid cleaning is performed to remove oil and shaving residue adhering during cutting when the cylindrical base material is produced. . By carefully performing this plating pretreatment, it is possible to prevent the occurrence of pinholes in the plating film to some extent, but it is difficult to eliminate the pinholes completely.

  And, it is difficult for the adhesive to enter inside the pinhole of the plating film, and it will be in a repelled state. That is, in the vicinity of the pinhole, the rubber layer is in direct contact with the cylindrical base material (or the plating film on the surface thereof) without the adhesive layer. Since the adhesive strength of the portion in direct contact is lower than that of the portion having the adhesive layer, the rubber layer is easily peeled off at that portion.

  Here, the depth of the pinhole of the plating film is the maximum thickness of the plating film. Then, by forming the adhesive layer so that the thickness is equal to or greater than the thickness of the plating film, the adhesive penetrates into the pinhole, and a uniform adhesive layer is formed in the vicinity of the pinhole. It was.

  In addition, as a method of making the adhesive easily enter the pinhole, a method of reducing the viscosity of the adhesive or a method of improving the wettability of the adhesive with respect to the plating film can be considered. However, suitable viscosity and wettability differ depending on the combination of the plating film and the adhesive, and need to be adjusted depending on the type of product. Moreover, even if the adhesive easily enters the pinhole by adjusting the viscosity and wettability, the absolute amount of the adhesive must be adjusted in order to fill the entire pinhole with the adhesive. If the adhesive layer is formed so as to have a thickness equal to or greater than the thickness of the plating film as in the present invention, the entire interior of the pinhole is filled with the adhesive regardless of the combination of the plating film and the adhesive. And a uniform adhesive layer can be formed in the vicinity of the pinhole.

  A thicker adhesive layer is preferable from the viewpoint of uniformly forming the adhesive layer, but if it is too thick, there may be a problem in cost and function (adhesiveness). Therefore, the thickness of the adhesive layer is preferably 1 to 5 times the thickness of the plating film, and more preferably 1.5 to 3 times. For example, 30 μm or less is preferable, and 1 to 20 μm is more preferable.

  An adhesive bond layer can be formed by apply | coating an adhesive agent to the cylindrical base material in which the plating film was formed in the surface. Examples of the coating method include bar coating, dip coating, spray coating, roll coating, gravure coating, flexo coating, and flow coating. Then, drying etc. can also be performed as needed. The application amount of the adhesive is appropriately adjusted so that the final adhesive layer has a predetermined thickness.

  In the present invention, it is important to form an adhesive layer having a thickness equal to or greater than the thickness of the plating film, and does not depend on the type of the plating film. That is, electroless plating or electrolytic plating may be used, and a plating method and material suitable for the function and cost of the rubber roller can be selected.

  The rubber composition for forming the rubber layer of the rubber roller of the present invention is not particularly limited as long as it is a composition obtained by adding a vulcanizing agent to the rubber component, and is appropriately selected from the use of the rubber roller. be able to. Examples of the main rubber component include ethylene-propylene-diene copolymer rubber (EPDM), natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), and acrylonitrile. Examples thereof include butadiene rubber (NBR), epichlorohydrin rubber (CO, ECO, GECO), acrylic rubber (ACM), and silicone rubber.

  The vulcanizing agent is not particularly limited as long as it contains a sulfur atom, and for example, sulfur, sulfur donor, triazine thiol, and 2,3-dimethylquinoxaline can be used. Examples of the sulfur donor include tetramethyl thiuram disulfide (TETD), tetrabutyl thiuram disulfide (TBTD), dipentamethylene thiuram disulfide (TRA), 2- (4′-morpholinodithio) benzothiazole (MDB), 4, 4'-dithiodimorpholine etc. are mentioned. The addition amount of the vulcanizing agent is appropriately selected so as to satisfy the characteristics required for the rubber roller.

  If necessary, additives such as a conductive material and a release material can be added to the rubber composition.

  The thickness of a rubber layer can be suitably selected according to the application site | part of a rubber roller, for example, a 0.5-10 mm rubber layer can be formed.

  The rubber layer is formed by applying a vulcanized rubber composition to the surface of a cylindrical base material and vulcanizing it, molding the vulcanized rubber composition into a tube shape and press-fitting it into the cylindrical base material, unvulcanized The rubber composition may be extruded into a cylindrical shape, and at the same time, the cylindrical substrate may be passed through a crosshead die and coated, and then vulcanized.

  The method for vulcanizing the rubber composition is not particularly limited, and can be performed by a conventionally known method such as hot-air furnace vulcanization or far-infrared vulcanization.

  EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited at all by these examples.

<Production method of rubber roller>
First, an electroless nickel plating film was formed on the surface of a cylindrical substrate. Specifically, after the treatment of alkaline degreasing, water washing, pickling and water washing was performed in this order on a steel cylindrical base material having a diameter of 6 mm and a length of 240 mm, a plating film was produced by electroless nickel plating. . As electroless nickel plating solution, commercially available Schumer S751 manufactured by Nippon Kanisen Co., Ltd. (trade name, nickel sulfate hexahydrate, sodium hypophosphite monohydrate, complexing agent, nitric acid as stabilizer) A plating solution in which 10 L (containing an appropriate amount of lead) and 40 L of pure water was mixed was used. In a state where the temperature in the bath of the plating bath containing the plating solution was maintained at 90 ° C., the cylindrical base material was placed in a stainless steel basket and immersed in the plating bath. The immersion time was 15 minutes, and the thickness of the plating film formed on the outer peripheral surface of the cylindrical base material was 5 μm. Thereafter, the plating solution was recovered, and the cylindrical substrate on which the plating film was formed was washed with water (10 seconds with pure water at a flow rate of 3 L / min for 10 seconds) and dried (80 ° C. × 15 minutes).

  Next, a synthetic rubber adhesive (trade name: ThreeBond 3315E, manufactured by Three Bond Co., Ltd.) is finally applied to the outer peripheral surface excluding 10 mm from both end faces of the cylindrical base material on which the plating film is formed, by a roll coating method. A uniform adhesive layer was uniformly applied to a predetermined thickness and dried at 120 ° C. for 10 minutes. Thereafter, an unvulcanized EPDM sulfur vulcanized composition (trade name: EPT4070, manufactured by Mitsui Chemicals, Inc.) is extruded into a cylindrical shape using an extruder, and at the same time, the cylindrical substrate is continuously cross-headed. The unvulcanized rubber composition was coated on the entire outer peripheral surface of the cylindrical base material. Thereafter, vulcanization treatment (conditions: temperature 190 ° C., time 30 minutes) was performed to form a rubber layer on the outer peripheral surface of the cylindrical base material. The overall outer diameter was 11 mm (rubber layer thickness was 2.5 mm).

  Further, while rotating this roller, a cutter blade was put at a position 10 mm from both ends, and the rubber layers at both ends of the columnar base material to which no adhesive was applied were removed. As for the obtained rubber roller, the longitudinal cross-sectional view is shown in FIG. 1, and the rubber layer 4 is formed through the adhesive layer 3 on the cylindrical base material 1 on which the plating film 2 is formed. .

<Evaluation method of presence or absence of peeling of rubber layer>
Apply the force to peel off the rubber layer of the rubber roller obtained by the above method from the cylindrical base material so that it is peeled with a finger, ○ if the rubber layer did not peel ○, about what the rubber layer peeled Regardless of x.

<Examples 1-3>
In Examples 1 to 3, rubber rollers were prepared so that final adhesive layer thicknesses were 5 μm, 7 μm, and 10 μm, respectively. No rubber layer was peeled off in any of the rubber rollers.

<Comparative Examples 1-3>
In Comparative Examples 1 to 3, rubber rollers were prepared so that the final adhesive layer thickness was 1 μm, 2 μm, and 4 μm, respectively. In any rubber roller, there was a site where the rubber layer was peeled off. The more the part which peeled, the more the adhesive thickness was seen. Further, pinholes were found in the plating film at the peeled site.

  The above results are summarized in Table 1. Thereby, it turned out that the rubber roller of this invention is a high quality rubber roller with which peeling of a rubber layer does not generate | occur | produce.

It is sectional drawing of the longitudinal direction of the rubber roller of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical base material 2 Plating film 3 Adhesive layer 4 Rubber layer

Claims (1)

In a rubber roller having a cylindrical base material with a plating film formed on the surface and a rubber layer formed on the plating film via an adhesive layer, the thickness of the adhesive layer is the thickness of the plating film A rubber roller characterized by the above.

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