JP4137628B2 - Method for manufacturing foam roller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a foam roller used in, for example, a printer, and more particularly to a method of directly vulcanizing and foaming an unvulcanized rubber foam by heating with pressurized steam.
[0002]
[Prior art]
Conventionally, a roller used for a charging roller, a developing roller, a transfer roller, or the like of a copying machine or a printer is provided with a cylindrical roller body on the outer periphery of a metal or resin shaft. It is formed of an elastic body made of a foamed material such as rubber or elastomer.
As a method for producing the above-mentioned foaming roller, methods such as mold vulcanization using a hot platen press, direct steam vulcanization using a vulcanizing can, hot air vulcanization, microwave vulcanization, etc. However, direct steam vulcanization using a vulcanizing can in which heat is uniformly applied to a workpiece (foam) to be vulcanized is often used. In this direct steam vulcanization method, as shown in FIG. 3, an unvulcanized rubber foam 10 molded in advance in a roll shape is sealed in a vulcanizing can 21 previously maintained at a predetermined temperature, and then a boiler is used. 22 or the like, heating steam is introduced into the vulcanizing can 21 to raise the temperature in the vulcanizing can 21 to the vulcanization temperature of the unvulcanized rubber foam 10, and the temperature and pressure of the heating steam The unvulcanized rubber foam 10 is vulcanized and foamed.
In order to uniformly foam the unvulcanized rubber foam 10, it is necessary to balance the foaming reaction and the vulcanization reaction of the unvulcanized rubber foam 10. The temperature rise rate in the vulcanized can 21 is controlled, or the temperature in the vulcanized can 21 is maintained for a predetermined time at a temperature lower than the reaction temperature of the foaming agent contained in the unvulcanized rubber, and then the unvulcanized rubber foam 10. Attempts have been made to raise the temperature in the vulcanizing can 21 up to the vulcanization temperature.
[0003]
[Problems to be solved by the invention]
However, since the above method controls only the temperature in the vulcanized can 21, uniform foaming cannot be obtained if the internal temperature of the unvulcanized rubber foam 10 that is a workpiece is uneven. There was a problem. Specifically, when the size of the workpiece to be processed is changed or the number of workpieces is different, even if the temperature in the vulcanized can 21 is a predetermined temperature, the internal temperature of the unvulcanized rubber foam 10 is maintained. Unevenness is likely to occur. Therefore, in order to foam the unvulcanized rubber foam 10 uniformly, it is necessary to perform fine temperature control for each processing lot.
[0004]
The present invention has been made in view of conventional problems, and provides a method for manufacturing a foam roller that can uniformly foam an unvulcanized rubber foam regardless of the work size and the number of works. Objective.
[0005]
[Means for Solving the Problems]
According to a first aspect of the present invention is a method of manufacturing a foamed roller which is heated vulcanizing and foaming the pre-roll shape molded the unvulcanized rubber foam having a shaft insertion hole directly pressurized steam In addition, a thermocouple is attached to the surface of the unvulcanized rubber foam and the inner wall side of the shaft insertion hole, and the unvulcanized rubber foam is placed at a temperature higher than the reaction temperature of the foaming agent contained in the unvulcanized rubber. At low temperature, vulcanized and foamed after preheating until the temperature difference between the center and surface of the unvulcanized rubber foam measured by each thermocouple is within a predetermined temperature. It is what. In other words, the unvulcanized rubber foam is preheated and then vulcanized and foamed so that the temperature of the unvulcanized rubber foam itself is uniform, not the environmental temperature such as the temperature inside the vulcanized can. By doing so, the uniformity of the foamed cells can be improved, so that the unvulcanized rubber foam can be uniformly foamed.
According to a second aspect of the invention, Te manufacturing method odor of the foam roller according to claim 1, as the temperature difference between the central portion and the surface of the upper Symbol unvulcanized rubber foam is within 15 ° C., the The unvulcanized rubber foam is preheated.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are diagrams showing a method of manufacturing a foam roller according to the present embodiment. In the figure, 10 is a workpiece, an unvulcanized rubber foam previously formed into a roll shape, and 21 is the above-mentioned A vulcanized can for vulcanizing and foaming the unvulcanized rubber foam 10, 22 is a boiler for introducing heated steam into the vulcanized can 21, and 23 a and 23 b are surfaces of the unvulcanized rubber foam 10. And the inner wall side of the shaft insertion hole 10S provided in the unvulcanized rubber foam 10 for measuring the temperature at the center and the surface of the unvulcanized rubber foam 10 respectively. , 24 is a temperature difference measuring device for calculating the temperature difference between the center and the surface of the unvulcanized rubber foam 10 from the output difference between the thermocouples 23a and 23b, and 25 is in the vulcanizing can 21. Temperature that is installed and measures the temperature of the vulcanizing can 21 Based on the temperature data in the vulcanizing can 21 output from the measuring means 21T and the data on the temperature difference between the center and the surface of the unvulcanized rubber foam 10 output from the temperature difference measuring device 24. A heating control device 26 that controls the boiler 22 and adjusts the temperature and pressure of the heated steam introduced into the vulcanizing can 21, transfers the unvulcanized rubber foam 10 into the vulcanizing can 21, It is a conveying device for taking out the unvulcanized rubber foam 10 from the vulcanized can 21 and conveying it.
[0007]
As a method of attaching the thermocouples 23a and 23b, for example, as shown in FIG. 2 (a), in the case where the shaft insertion hole 10S penetrates the unvulcanized rubber foam 10, one thermocouple is used. The pair 23a is fixed to the surface of the unvulcanized rubber foam 10 with the heat-resistant tape 31, and the other thermocouple 23b is attached to the outer peripheral side of the central portion of the dummy shaft 32. The dummy shaft 32 is attached to the unvulcanized rubber foam. What is necessary is just to insert in the shaft insertion hole 10S provided in 10. In the case where the shaft insertion holes 10p and 10q are provided at both ends of the unvulcanized rubber foam 10, as shown in FIG. 2B, the shaft is inserted into one shaft insertion hole 10p. A method of inserting a thermocouple 23b for measuring the temperature of the central portion of the unvulcanized rubber foam 10 in the protective tube 33 is conceivable. A dummy shaft 32 'is inserted into the other shaft insertion hole 10q. Thereby, the temperature of the center part and the surface of the said unvulcanized rubber foam 10 can be measured correctly.
[0008]
Next, the manufacturing method of the foaming roller by this invention is demonstrated.
First, after attaching thermocouples 23a and 23b to the surfaces of a plurality of unvulcanized rubber foams 10 to be foamed and the shaft insertion holes 10S of the unvulcanized rubber foams 10, respectively, The vulcanized rubber foam 10 is set in the vulcanizing can 21 by the conveying device 26, and the temperature difference measuring device 24 is connected to the cords of the thermocouples 23 a and 23 b with the lid member 21 F of the vulcanizing can 21 as a relay point. Are attached to input terminals (not shown). Next, heating steam from the boiler 22 is introduced into the vulcanizing can 21, and the inside of the vulcanizing can 21 is set to a predetermined temperature T 1 (for example, lower than the reaction temperature of the foaming agent contained in the unvulcanized rubber foam 10). , 110 ° C.) and preheating the unvulcanized rubber foam 10. At this time, the heating control device 25 controls the temperature inside the vulcanizing can 21 to be the temperature T1, and the center portion and the surface of the unvulcanized rubber foam 10 output from the temperature difference measuring device 24. Whether or not the temperature difference ΔT is less than a predetermined value (for example, 10 ° C.) is monitored. If the temperature difference ΔT is larger than the predetermined value, the temperature in the vulcanizing can 21 is left as it is. The boiler 22 is controlled so that the temperature and pressure of the heating steam introduced into the vulcanizing can 21 are adjusted.
[0009]
When the temperature difference ΔT becomes a predetermined value (for example, 10 ° C.) or less, the boiler 22 is controlled so that the temperature in the vulcanizing can 21 is set to a predetermined vulcanization / foaming temperature. The temperature is increased at a predetermined temperature increase rate up to T2 (for example, 150 ° C.). Thereafter, the unvulcanized rubber foam 10 is vulcanized / foamed while being held at the vulcanization / foaming temperature T2 for a predetermined time. After completion of the vulcanization / foaming treatment, the water vapor in the vulcanization can 21 is discharged from an exhaust valve (not shown), and the unvulcanized rubber foam 10 is taken out.
Thereby, since the temperature of the unvulcanized rubber foam 10 itself at the time of preheating can be made uniform, the uniformity of the foamed cells can be increased, and the unvulcanized rubber foam can be uniformly foamed. At this time, the temperature difference ΔT is preferably within 15 ° C., particularly preferably within 10 ° C.
For example, when the temperature difference ΔT between the center portion and the surface of the unvulcanized rubber foam 10 is 30 ° C., the average cell diameter of the vulcanized / foamed sponge rubber is 200 μm (distribution width; 500 μm). The cell wall thickness distribution width was also 150 μm and the variation of the foamed cells was large, but when the temperature difference ΔT was 10 ° C., the cell diameter was 100 μm on average (distribution width; up to 150 μm), and the cell The distribution width of the wall thickness was 70 μm, and the uniformity of the foamed cells could be greatly improved.
In addition, since the temperature of the unvulcanized rubber foam 10 itself is directly measured by the thermocouples 23a and 23b and preheating is performed, the unvulcanized rubber foam 10 regardless of the workpiece size and the number of workpieces. Can be uniformly foamed.
[0010]
The plurality of unvulcanized rubber foams 10 to be vulcanized / foamed preferably have the same workpiece size. In this case, it is not necessary to attach the thermocouples 23a and 23b to all the unvulcanized rubber foams 10. For example, when processing a plurality of unvulcanized rubber foams 10 in a row, it is sufficient to attach the thermocouples 23a and 23b only to the unvulcanized rubber foams 10 located at both ends and the center. is there. In the case of multi-stage arrangement, the thermocouples 23a and 23b may be attached only to the unvulcanized rubber foam 10 located at both ends and the center of each stage.
[0011]
As raw materials for the unvulcanized rubber foam 10 of the present invention, polyurethane rubber, silicone rubber, butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber A rubber composition using epichlorohydrin rubber or the like as a base rubber is exemplified. As the foaming agent, organic foaming agents such as azodicarbonamide, dinitrosopentamethylenetetraamine, and oxybisbenzenesulfenylhydrazide can be used.
Further, examples of the vulcanizing agent include sulfur and metal oxides, and examples of the vulcanization accelerator include thiazole-based, sulfonamide-based, and thyrium-based.
In addition, known foaming aids, vulcanization acceleration aids, reinforcing agents, inorganic fillers, and the like can be added as necessary.
[0012]
【The invention's effect】
As described above, according to the present invention, in the method of manufacturing a foam roller in which an unvulcanized rubber foam provided with a shaft insertion hole formed in advance in a roll shape is directly heated with pressurized steam to vulcanize and foam. In addition, a thermocouple is attached to the surface of the unvulcanized rubber foam and the inner wall side of the shaft insertion hole, and the unvulcanized rubber foam is placed at a temperature higher than the reaction temperature of the foaming agent contained in the unvulcanized rubber. At low temperature, vulcanization / foaming was performed after preheating until the temperature difference between the center and surface of the unvulcanized rubber foam measured by each thermocouple was within a predetermined temperature. The uniformity of the cells can be improved, and the unvulcanized rubber foam can be uniformly foamed. In addition, the unvulcanized rubber foam can be uniformly foamed regardless of the workpiece size and the number of workpieces.
[Brief description of the drawings]
FIG. 1 is a diagram showing a method for manufacturing a foam roller according to the present embodiment.
FIG. 2 is a diagram showing an example of a thermocouple mounting position.
FIG. 3 is a diagram showing a conventional method for manufacturing a foam roller.
[Explanation of symbols]
10 Unvulcanized rubber foam, 10S, 10p, 10q Shaft insertion hole,
21 vulcanizing can, 21T temperature measuring means, 22 boiler,
23a, 23b thermocouple, 24 temperature difference measuring device, 25 heating control device,
26 transport device, 31 heat-resistant tape, 32, 32 'dummy shaft,
33 Protection tube.

Claims (2)

In a method of manufacturing a foam roller in which an unvulcanized rubber foam having a shaft insertion hole formed in advance in a roll shape is directly heated with pressurized steam to vulcanize and foam, the surface of the unvulcanized rubber foam and the above The thermocouple was attached to each of the inner wall side of the shaft insertion hole, and the unvulcanized rubber foam was measured by the thermocouple at a temperature lower than the reaction temperature of the foaming agent contained in the unvulcanized rubber. A method for producing a foaming roller, characterized in that the unvulcanized rubber foam is preheated until the temperature difference between the center portion and the surface is within a predetermined temperature and then vulcanized and foamed. 2. The foam roller according to claim 1 , wherein the unvulcanized rubber foam is preheated so that a temperature difference between a center portion and a surface of the unvulcanized rubber foam is within 15 ° C. 3. Production method.

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