JPS6236223B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a fixing roller, and in particular provides a method for easily manufacturing a silicone rubber fixing roller impregnated with silicone oil and having high dimensional accuracy. Conventionally, fixing rubber rollers used in copying machines such as electrophotographic copying machines have been known to have a heat-resistant silicone rubber layer formed to a certain thickness on the outer circumferential surface of a metal shaft (metal roll). It is being In order to manufacture such a fixing roller made of silicone rubber, a silicone rubber composition (RTV) that hardens at room temperature is used as the silicone rubber material, or a silicone rubber composition that becomes a rubber elastic body by curing under pressure and heat is used. In the former RTV, this composition is formed on the surface of a metal shaft to a desired thickness by an appropriate method such as using a doctor knife, calendar molding method, or transfer molding method, and then heated at room temperature. Alternatively, the composition may be cured by slight heating, and then its surface may be polished and finished. In the latter HTV, heat and pressure processing may be performed using a mold, or the composition may be applied to the surface of the shaft to a desired thickness. A commonly used method is to cover the material, wrap it tightly with cotton cloth, cure it by steam curing, and then finish the surface by polishing. However, the method using RTV requires a complicated process for forming a silicone rubber layer on the surface of the metal shaft, and the rubber layer inherently has poor mechanical strength, making it difficult to withstand long-term use. There is a drawback that there is no On the other hand, the method using HTV has problems in that the steps are similarly complicated and impregnation with silicone oil is accompanied by great difficulty. In other words, the hardened layer (silicone rubber layer) of this polished HTV needs to be impregnated with silicone oil to prevent toner offset (uneven fixation, stains on printing paper). 100-200 in advance to carry out impregnation.
The method used is to swell the silicone rubber layer by contacting it with silicone oil heated to a temperature of °C for 8 to 72 hours, but in this case, it is quite difficult to uniformly penetrate the silicone oil into the silicone rubber layer. Another disadvantage is that a troublesome step is required to ensure the required dimensional accuracy by polishing the surface of the swollen silicone rubber layer again. The present invention solves such conventional disadvantages and disadvantages.
The present invention aims to provide a method for easily manufacturing a silicone rubber fixing roller impregnated with silicone oil and having high dimensional accuracy.This method involves dipping a silicone rubber hollow tube in an organic solvent solution of silicone oil to This method is characterized by impregnating rubber with silicone oil, inserting it into a metal shaft, and then subjecting it to heat treatment. In particular, the organic solvent is aliphatic or aromatic hydrocarbons and halogenated hydrocarbons. A method of using a solvent selected from: According to the method of the present invention, (1) it is extremely easy to form a silicone rubber layer on the surface of a metal shaft, and (2) silicone oil can easily penetrate into the silicone rubber layer at room temperature, resulting in a uniform coating. (3) Especially in the silicone oil-impregnated layer, the concentration gradient of the amount of oil impregnated depending on the penetration depth from the surface is extremely small (the amount of impregnation is uniform), and during impregnation, the silicone oil is mixed into the silicone rubber. Since the impregnation penetrates from both the inside and outside of the hollow tube, the impregnation time is shorter than that of conventional methods. (4) The silicone rubber hollow tube to be inserted is reliably manufactured with the desired dimensional accuracy using methods such as extrusion molding. The smoothness of the surface is not impaired even after impregnation with silicone oil, so polishing is not necessarily required. (6) It also has the advantage that dimensional changes and distortions are less likely to occur even when silicone oil is supplied. The method of the present invention will be explained in detail below. In the method of the present invention, a silicone rubber hollow tube that is inserted into a metal shaft that serves as a support for a rubber roller is prepared in advance. By extrusion molding a conventionally known pressurized and heat-curable silicone rubber composition containing as a main component, a hollow tube with a desired inner diameter, constant wall thickness, and smooth surface can be obtained. . The silicone rubber hollow tube obtained as described above is then immersed in an organic solvent solution of silicone oil, thereby impregnating the silicone rubber with silicone oil. It is required that it stably penetrates into the rubber and exhibits the effect of preventing toner offset, and from this point of view, this product has a viscosity of approximately 5 to 2000 at 20°C.
A silicone oil exhibiting centistokes (preferably 20 to 500 centistokes), such as dimethyl silicone oil, is desirable. The organic solvent for dissolving the silicone oil is preferably one that is a good solvent for the silicone oil and has the ability to swell the silicone rubber, such as solvents selected from aliphatic or aromatic hydrocarbons and halogenated hydrocarbons. Examples include cyclohexane, benzene, toluene, xylene, carbon tetrachloride, trichloroethylene, and gasoline. If the concentration of silicone oil dissolved in these organic solvents is too low, it will be difficult to achieve the desired amount of silicone oil impregnated into the silicone rubber, whereas if it is too high, it will be difficult to achieve the desired amount of silicone oil impregnated into the silicone rubber. Therefore, it is desirable that this amount be approximately 20 to 60% by weight (preferably 30 to 50% by weight). When the silicone rubber hollow tube is immersed in this silicone oil solution in an organic solvent, the silicone rubber is swollen by the swelling action of the organic solvent, and as a result, the silicone oil quickly permeates into the silicone rubber. The temperature during dipping may be room temperature, and heating is not particularly required. The content of silicone oil in the silicone rubber varies depending on the hardness of the rubber, the quality of the material, etc., but it is usually desirable to keep it at 5 to 15% by weight. After impregnating with silicone oil as described above, it is inserted into a metal shaft that serves as a support, and then heated to remove most of the solvent and impregnate silicone oil at the desired concentration. A silicone rubber fusing roller is obtained. In addition, when inserting a silicone rubber hollow tube, it is effective to apply adhesive to the surface of the metal shaft in advance if necessary, and this will further strengthen the metal shaft and silicone rubber hollow tube. It can be fixed and integrated. Since the fixing roller thus obtained has a smooth surface and excellent dimensional accuracy, it is not particularly necessary to polish it again. Next, examples of the present invention will be given. Example 1 By extrusion molding, the inner diameter is 24 mm, the outer diameter is 34 mm, and the length is
We made a 300mm silicone rubber hollow tube with a JIS hardness of 50. 1 of dimethyl silicone oil with a viscosity of 50 centistokes at 25°C and trichlorethylene:
The silicone rubber hollow tube was immersed in the 1 (weight) mixed solution and kept at 20° C. for 24 hours to obtain a swollen silicone rubber hollow tube having an inner diameter of 30 mm and an outer diameter of 51 mm. Next, this swollen silicone hollow tube was inserted into a metal shaft with a diameter of 30 mm, and the trichlorethylene was evaporated off in a vacuum dryer at 100°C. The silicone oil content in the silicone rubber was 13% by weight, and the JIS hardness of the silicone rubber was A silicone rubber fusing roller No. 46 was obtained. This fixing roller had an extremely smooth surface and did not require any polishing. Reference Example A cured silicone rubber sheet having a thickness of 20 mm was made using the same silicone rubber composition used to make the silicone rubber hollow tube of Example 1 above.
A test piece of this rubber sheet (height 5cm, width 10cm,
20 mm thick) was immersed in the same trichloroethylene solution of methyl silicone oil as in the previous example at 20°C for 24 hours. This was then taken out and the trichlorethylene was removed by evaporation in a vacuum dryer at 100°C, and the surface hardness (JIS) of this silicone oil-containing rubber was 46. For this rubber, the depth from the surface in the thickness direction is 1
When the JIS hardness of the sliced surface was measured at each section of mm, 2 mm, 2.5 mm, 3 mm and 4 mm, the results shown in the table were obtained. However, the measurements were made at two locations, one near the center and one near the ends of the test piece. In addition, in the comparative example in the table, a silicone rubber test piece was impregnated with silicone oil by immersing it only in silicone oil (same as in Example 1) heated to 150°C for about 20 hours, and the amount of silicone oil impregnated was almost the same. This is a case where they are made to be about the same level.

[Table] Example 2 Before inserting the swollen silicone rubber hollow tube obtained in the same manner as in Example 1 into a metal shaft, 2 parts by weight of 2,4-dichloroperbenzoate and a silicone rubber system were added to the surface of the metal shaft in advance. Adhesive (KE-701Bu: Shin-Etsu Chemical product name) 100
After uniformly applying the mixture with parts by weight, a swollen silicone rubber hollow tube was inserted, and then heated at 50°C and 10mmHg.
It was dried under reduced pressure. Next, a polyester heat-shrinkable tube was placed on the outside of this rubber hollow tube, and then heat treated in a dryer at 200° C. for 1 hour. Due to this heating, the shrink tube contracts and pressure is applied to the entire rubber hollow tube, and in this state the adhesive layer cures.
Complete adhesive integration of the metal shaft and rubber hollow tube was achieved. The thus obtained silicone rubber fixing roller had a silicone rubber JIS hardness of 46, had uniform hardness on the entire surface, was smooth, and had excellent durability.

Claims (1)

[Claims] 1. After immersing a silicone rubber hollow tube in an organic solvent solution of silicone oil to impregnate the silicone rubber with silicone oil, the tube is inserted into a metal shaft and then subjected to heat treatment. A method for manufacturing a fixing roller characterized by: 2. The fixing device according to claim 1, wherein the organic solvent solution of silicone oil is a solution of silicone oil in at least one organic solvent selected from aliphatic or aromatic hydrocarbons and halogenated hydrocarbons. How to manufacture rollers. 3. Claim 1, characterized in that when inserting a silicone rubber hollow tube into a metal shaft after impregnating it with an organic solvent solution of silicone oil, an adhesive layer is provided on the metal shaft in advance. Method of manufacturing the fusing roller described.