JPH05185534A - Manufacture of heat-resistant roller - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and toner mold release characteristics and prolong the lifetime of a roller, etc., while simplifying a process and reducing the working cost by kneading fluororesin powder and a vulcanizing agent with a silicone rubber and forming a surface layer in specified thickness on the outer circumference of a roller mandrel. CONSTITUTION:A heating roller 1 as a heat-resistant roller is installed to the fixing device 3 of a copier 2, and a heating section 14 is disposed at the central section of the roller l while a press roller 5 is pressure-welded to a circumferential surface section. A form 7 having an unfixed toner 6 is carried between both rollers 1, 4 by a belt 8. There are a single layer type and a two layer type in the heating roller 1. Fluororesin powder 14 is kneaded with a silicone rubber 13 and an unvulcanized layer is formed outside a roller mandrel 12 in the single layer type heating roller 1, and the unvulcanized layer is heated and vulcanized, thus forming a surface layer 15 as one layer. 2-50 pts.wt. is blended with the 100 pts.wt. silicone rubber in fluororesin powder, and mean particle size is set in 2-50mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant roller manufacturing method, for example, a heating roller or a pressure roller of a fixing unit of an image forming apparatus such as a copying machine, a platen roller of a facsimile machine, or a heat-resistant silicone of an office automation equipment. The present invention relates to a method for manufacturing a heat resistant roller such as a rubber roller.

[0002]

2. Description of the Related Art Generally, as a heating roller of a fixing unit of a copying machine, there is a heating roller in which a silicone rubber layer is formed on an aluminum metal core by coating and cured. A conventional heat-resistant roller using silicone rubber is disclosed in JP-A-63-
There is one described in Japanese Patent No. 142382. This is a case where the silicone rubber layer has two layers, and an inner layer formed by applying and drying a specific room temperature curable silicone rubber liquid, and an outer layer made of a room temperature curable silicone rubber are formed on the outer side of this inner layer.

In particular, in the case of a copying machine using color toners, the color toners have a stronger adhesive property when melted than the normal toners. Therefore, in order to prevent the adhesion and deposition of the toners, a special silicone rubber compound is added as an outer layer. Things are used. However, silicone rubber is generally weaker in strength than other rubber materials, easily scrapes the roller surface due to paper dust, and tends to cause uneven glossiness of an image, and has insufficient abrasion resistance and toner releasability. There are some which are mixed with additives such as titanium white, but the effect is small.

Further, as a conventional method for manufacturing a heat-resistant roller, there is, for example, a method described in JP-A-60-31855. This relates to a pressure roller of a fixing device, and as shown in FIG. 4, a silicone rubber is kneaded and adhered to the outer periphery of an aluminum cored bar to be integrally molded. A fluorine mixed solution in which a curing agent and a silane-based solvent are mixed is uniformly applied to a mixture of a fluorocarbon resin and a fluororesin, and then heat-treated to form a fluororesin layer.

[0005]

However, in such a conventional method for manufacturing a heat-resistant roller, the fluororesin layer uses fluororubber whose material is expensive, and the solvent is expensive silane-based solvent. Is used. Therefore, the cost is high, and since a silane-based solvent is used,
There is a problem that it adversely affects the environment.

The present invention has been made against the background of such a conventional technique, and a fluorocarbon resin powder and a vulcanizing agent are kneaded with silicone rubber to form an unvulcanized layer with a predetermined thickness on the outer periphery of the roller core metal. By forming the resin, heat vulcanizing it, and forming the surface layer, it has good wear resistance, good toner releasability, and can greatly extend the roller life. Also, the process is simple and small, and it is cheap and environmentally friendly. Moreover, the fluororesin powder can be dispersed well by setting the amount of the fluororesin powder to 2 to 50 parts by weight with respect to 100 parts by weight of the silicone rubber. It is an object of the present invention to provide a heat-resistant roller manufacturing method capable of further improving the wear resistance of the roller and the toner releasability by setting the thickness to 50 μm.

[0007]

The invention according to claim 1 is
A predetermined amount of silicone rubber, fluororesin powder and vulcanizing agent are individually weighed, and the fluororesin powder and vulcanizing agent are kneaded with the silicone rubber, and then an unvulcanized layer is formed on the outer periphery of the roller core metal to a predetermined thickness. Then, it is heated and vulcanized to form a surface layer.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the amount of the fluororesin powder is 2 to 50 parts by weight with respect to 100 parts by weight of the silicone rubber. In addition to the constitution of claim 1 or 2, the invention of claim 3 has an average particle size of 2 to 50 μm in the fluororesin powder.
It is characterized by being.

Here, the fluororesin material is silicon rubber 100
The amount of 2 to 50 parts by weight is used because the effect of the present invention is small when the amount is less than 2 parts by weight, and when the amount exceeds 50 parts by weight, dispersion is poor and roller scratches are likely to occur. The average particle size of the fluororesin powder is 2 to 50 μm because it is 2 μm.
If it is less than 50 μm, the effect of the present invention is small, and if it exceeds 50 μm, the dispersion is deteriorated.

[0010]

In the invention described in claim 1, since the silicone rubber, the fluororesin powder and the vulcanizing agent are weighed and kneaded, an unvulcanized layer is formed on the roller die and heat-vulcanized to form the surface layer. The manufacturing process is few and simple, and since expensive fluororubber is not used, it is inexpensive, and since no silane solvent is used, there is no environmental pollution, and abrasion resistance and releasability are also good.

According to the second aspect of the present invention, the amount of the fluororesin powder is 2 to 50 parts by weight, so that the dispersion in the silicone rubber is good and the roller is not scratched. In the invention of claim 3, since the average particle diameter of the fluororesin powder is 2 to 50 μm,
Dispersion in silicone rubber is good and roller scratches do not occur.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of a method for manufacturing a heat resistant roller according to claims 1 to 3 of the present invention. FIG. 1 is a diagram showing a copying machine 2 which uses a fixing device 3 having a heat roller 1 which is a heat resistant roller manufactured by the method for manufacturing a heat resistant roller of the present invention. The outline will be described below with reference to FIG. The heating roller 1 has a heating unit 4 at the center, and a pressure roller 5 is pressed against the heating roller 1 with a constant pressing force. The paper 7 having the unfixed toner 6 transferred from the photoconductor of the copying machine 2 is conveyed by the conveyance belt 8 so as to pass between the heating roller 1 and the pressure roller 5. At this time, the unfixed toner 6 on the paper 7 is fused and fixed between the roller nips.
The pressure roller 5 is often made of silicone rubber or silicone rubber coated with a fluororesin.

The heating roller 1 includes one layer and two layers. As shown in FIG. 1 (b), the one-layer heating roller 1 is manufactured on the outer side of a cylindrical roller cored bar 12 by the method for manufacturing a heat-resistant roller according to the present invention according to the flow of the manufacturing process shown in FIG. The heating roller 1 is formed by forming a single unvulcanized layer in which a fluororesin powder 14 is kneaded in a silicone rubber 13 and heat-treated to form a single surface layer 15. As shown in FIG. 3, in the two-layer heating roller 1, a silicone rubber layer having a strong adhesive force with the roller core metal 12 is provided on the outer side of the roller core metal 12 as the inner layer 21, and a surface layer 15 is provided on the outer side of the inner layer 21. A surface layer 15 made of a silicone rubber 13 containing a fluororesin powder is provided to improve releasability and wear resistance. Also,
In the case of two layers, it is possible to lower the apparent hardness of the roller as a whole by softening the rubber of the inner layer 21, and it is also possible to improve the fixing rate by increasing the nip width with the pressure roller 5. ..

Next, 11 kinds of one-layer heating rollers 1, that is, Examples 1 to 6 and Comparative Examples 1 to 5 were manufactured by the method for manufacturing a heat-resistant roller according to the present invention, and comparative tests were conducted. This will be described with reference to 1. FIG. 2 shows a flow of manufacturing steps of the one-layer heating roller 1 of the present invention. First, in each of the samples, a silicone rubber 13, a fluororesin powder 14 having an average particle size of 1.5 to 60 μm, a vulcanizing agent, etc. are prepared,
Sample Nos. 1 and 2 shown in Table 1, respectively. According to the above, a predetermined amount (addition amount) is weighed by an ordinary weighing machine. As the silicone rubber 13, a heat vulcanizing type silicone rubber (DY-32-904U manufactured by Toray Dow Corning Silicone Co., Ltd.) was used.

In compounding and kneading, as shown in Table 1, the fluororesin powder has an average particle size of 20 μm and a surface area of 10 m ² / g.
Apparent density 350 ~ (measured by normal nitrogen adsorption method)
400 g / L (measured according to American standard ASTM-1457)
As a curing agent which is a vulcanizing agent, RC-4 (manufactured by Toray Dow Corning Silicone Co., Ltd.) was added in an amount of 0.8 part by weight. The amount of fluororesin powder added varied from 0, 1, 5, 20, 40, 100 parts by weight to 100 parts by weight of silicone rubber. In addition, assuming that the average particle size of the fluororesin powder is changed, the average particle size is 1.5 μm, 3 μm, 10 μm, 50 μm.
m and 60 μm were used by weighing 20 parts by weight with respect to 100 parts by weight of silicone rubber. Next, these silicone rubber 13, fluororesin powder 14 and curing agent were kneaded by an open roll until they were sufficiently dispersed. When the fluororesin was dispersed in the silicone rubber, the processability was also poor when the average particle size of the fluororesin was as large as 60 μm or when the addition amount was as large as 100 parts by weight. These compounded rubbers after kneading were coated with a predetermined thickness on the outer periphery of the roller cored bar prepared in advance to form an unvulcanized layer, which was vulcanized at a temperature of 160 ° C. for 15 minutes. Further, secondary vulcanization was performed at a temperature of 180 ° C. for 24 hours to form a heating roller 1 having a surface layer 15 made of a fluororesin-containing silicone rubber. If necessary, the surface may be ground.

Each of these heating rollers 1 was attached to the fixing device 3 of the copying machine 2 described above, and plain paper was passed through for test evaluation. The evaluation was carried out by measuring the abrasion resistance of the heating roller 1 in the state of occurrence of roller scratches on the roller surface, 10,000 sheets, 50,000 sheets, 10 sheets.
At the time of 10,000 sheets, the judgment is confirmed with a microscope of 100 times,
The releasability of the toner was visually evaluated by checking the surface stains on the roller after passing 1,000 sheets. In addition, comprehensive judgment results are shown based on these roller stains and roller scratches.

The judgment results were judged to be excellent, good and bad, and in the table, the state of occurrence of roller stains and roller scratches is shown by ⊚, ◯ and ×, and in the comprehensive judgment, excellent, good and bad are shown. In the table, in Examples 1 to 6, the overall judgment was excellent or good, but the others were not (un). In addition, when the orientation of the fluororesin was utilized during the trial manufacture of the roller to perform the orientation in a certain direction, good results were obtained for the roller scratches and the releasability.
In addition, it is possible to use an injection molding machine to orient the fluororesin in the roller axis direction, and it goes without saying that a special construction method is required to orient the fluororesin in the direction perpendicular to the roller axis (core bar). Nor.

[0018]

[Table 1]

[0019]

According to the invention of claim 1, the wear resistance is improved by forming a surface layer of a predetermined thickness on the outer periphery of the roller core metal by kneading fluorocarbon resin powder and a vulcanizing agent into silicon rubber. And the toner releasability is good, the roller life can be greatly improved, the process is simple and small, the working cost can be reduced, and the environmental pollution can be eliminated.

According to the second aspect of the present invention, the amount of the fluororesin powder is 2 to 50 parts by weight with respect to 100 parts by weight of the silicone rubber, whereby the fluororesin powder can be dispersed well.
Workability can be improved and abrasion resistance can be improved. According to the invention of claim 3, the average particle diameter of the fluororesin powder is 2
By setting the thickness to 50 μm, the dispersion is good, the abrasion resistance of the roller and the releasability of the toner can be further improved, and the quality of the copied image can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a heating roller obtained by a method for manufacturing a heat-resistant roller according to claims 1 to 3 of the present invention, FIG. 1A is an overall sectional view of a fixing device of a copying machine to which the heating roller is applied, (B) is a sectional view of the heating roller.

FIG. 2 is a diagram showing a flow of steps in a method for manufacturing the heat resistant roller shown in FIG.

FIG. 3 is a cross-sectional view showing another example of the heating roller by the method for manufacturing a heat resistant roller according to claims 1 to 3 of the present invention.

FIG. 4 is a diagram showing a conventional heat-resistant roller manufacturing method.

[Explanation of symbols]

 1 Heat resistant roller manufacturing method 12 Roller core 13 Silicone rubber 14 Fluororesin powder

Claims (3)

[Claims] 1. A silicone rubber, a fluororesin powder and a vulcanizing agent are respectively weighed and weighed, and the fluororesin powder and the vulcanizing agent are kneaded with the silicone rubber. A method for producing a heat-resistant roller, which comprises forming a vulcanized layer and vulcanizing by heating to form a surface layer. 2. The heat-resistant roller manufacturing method according to claim 1, wherein the fluororesin powder is contained in an amount of 2 to 50 parts by weight based on 100 parts by weight of the silicone rubber. 3. The fluororesin powder has an average particle size of 2 to 50 μm.
The method for manufacturing a heat resistant roller according to claim 1 or 2, wherein