JPH0439076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for manufacturing a heat fixing roller used in a fixing device of a silicone oil supply type electrophotographic copying machine.

(Technical Background of the Invention and Problems Thereof) Conventionally, in dry electrophotography, heat fixing is used as a means for fixing a powder image transferred from a transfer drum or the like onto a support such as paper, by applying pressure using a constant pressure. A commonly used method is to press and fix a powder image onto a support by passing it between a roller and a pressure roller.

As the coating layer of the heat fixing roller used in such means, tetrafluoroethylene, silicone rubber, fluorocarbon, etc. are used.
Silicone rubber is used as the heat-resistant elastic material for the pressure roller, and during fixing, an offset prevention liquid such as silicone oil is applied to the surface of the heated fixing roller.

Among the heat fixing rollers mentioned above, those whose surfaces are coated with silicone rubber at a certain thickness have elastic surfaces, so they do not crush unfixed toner during fixing, and therefore produce good copies. Due to the benefits it provides, it has recently become widely used.

Furthermore, the coating layer made of silicone rubber has a wide range of roller temperature tolerance, and the toner image is less likely to be crushed, so it has the advantage of producing high-quality copies.
On the other hand, it is easily eroded by silicone oil and swells rapidly.

For this reason, fixing is carried out while applying silicone oil to a coating layer made of silicone rubber (Japanese Patent Publication No. 56-9704). During long-term use, the coating layer swells, the roll diameter increases, and the linear speed becomes faster than initially.

Furthermore, when copying is performed for a long period of time using sheets of different sizes, the degree of swelling differs between the center and both ends of the roll, which causes wrinkles in the copy paper.

Furthermore, in order to eliminate the above-mentioned drawbacks, after forming a silicone rubber coating layer, it is immersed in silicone oil to swell to a state at or close to swelling equilibrium, and the swollen part is ground to form a specified outer layer. It is also known to finish the paper to the same diameter (Japanese Patent Publication No. 58-30337), but it has the disadvantages that the swelling time is long, silicone oil is easily absorbed by the paper during paper passing, and the outer diameter of the paper passing part becomes narrower. are doing.

Furthermore, the scraps produced during the grinding process must be thrown away, which is economically disadvantageous.

(Object of the invention) The present invention has been made in view of the circumstances,
The purpose of this is to provide a method for manufacturing a heat fixing roller that minimizes changes in roller diameter caused by swelling with silicone oil, to prevent various defects caused by changes in roller diameter, and to improve the durability of the roller itself. This is an attempt to improve one's abilities.

(Summary of the Invention) The present invention involves forming a coating layer mainly composed of silicone rubber via a primer layer on the outer periphery of the core metal, polishing it to almost the final finished outer diameter, and then immersing it in silicone oil. The coating layer has an equilibrium swelling value.
It is characterized by stopping swelling at 40-80% and then finishing it to a predetermined outer diameter.

By performing polishing in the present invention after the primary vulcanization and before the secondary vulcanization, the thickness to be subjected to the secondary vulcanization is reduced accordingly, so that the secondary vulcanization time can be further shortened. Furthermore, to coat the silicone rubber layer, after applying the primer on the core bar and pre-baking it at a temperature below 130℃ for 30 minutes, apply silicone rubber with the same composition as the silicone rubber on the surface of the primer.
If the silicone rubber layer is formed after preheating to above ℃, the time required to form the silicone rubber layer can be shortened by preheating the core metal, and since the primer is prebaked, the functional groups in the primer will not react with the silicone rubber. This further improves adhesion.

Note that polishing in the present invention includes grinding.

Next, an embodiment of the method of the present invention will be described.

Example 1 After applying a primer to an aluminum metal core (diameter 29 mm), air dry it and apply silicone rubber to its outer periphery.
After coating TSE270-6U (manufactured by Shin-Etsu Chemical Co., Ltd.) to a thickness of 1.5 mm, primary vulcanization was performed at 150°C for 30 minutes, followed by secondary vulcanization at 200°C for 1 hour.

Thereafter, the coating layer was ground to an outer diameter of 30.0 mm, and this was left in dimethyl silicone oil 100CS (25°C) set at 180°C ± 2°C for 8 hours. After cooling, the outer diameter was measured to be 30.4 mm (70% of the equilibrium swelling value). This swollen roller was polished to produce a heat fixing roller with an outer diameter of 30.0 mm.

Next, while applying silicone oil liquid to the surface of the coating layer of this heat fixing roller, the surface temperature is adjusted.
When the copy paper was fixed at 180℃, there were no wrinkles at all, and the outer diameter after 20,000 sheets was 30.03mm.
It was hot.

Example 2 A roller was manufactured in the same manner as in Example 1 up to the primary vulcanization part, and immediately after the primary vulcanization, it was ground to 30.0 mm.
After setting the outer diameter to 200°C for 50 minutes,
Thereafter, a roller was manufactured in the same manner as in Example 1.
When a fixing test was conducted in the same manner as in Example 1, the outer diameter after passing 20,000 sheets was 30.03 mm, and
The coating layer did not peel off even after 80,000 sheets were printed.

Example 3 In Example 1, air drying was not performed, but the temperature was 130°C or lower, for example.
After pre-baking at 100°C for 20 minutes, apply the same type of rubber as the silicone rubber to be coated onto the primer surface to a thickness of 0.1 mm, preheat it to 135°C or higher, and then manufacture the roller in the same manner as in Example 1. did.

A fixing test was conducted in the same manner as in Example 1, and almost the same results were obtained.

Further, leave it at 260℃ for 6 hours and test for adhesive failure (ASTM standard D1002-64; tensile shear test)
When I tried this, it broke between the rubber and the rubber.

Conventional Example In Example 1, the oil immersion time was set to 36 hours (approximately 100% of the equilibrium swelling value), and the roller was polished once after the oil immersion to produce a roller having an outer diameter of 30.0 mm. When a fixing test was conducted in the same manner as in Examples 1 to 3, the outer diameter after 20,000 sheets was 30.1 mm, and the coating layer peeled off at 70,000 sheets, and furthermore, in the adhesive failure test, it was destroyed by the primer and the rubber surface. .

(Effects of the Invention) As is clear from the above embodiments, the method for manufacturing a heat fixing roller of the present invention has a method for manufacturing a heat fixing roller in which there is little change in the diameter of the roller in the radial direction of the roller after paper passes, and the diameter of the roller in the axial direction of the roller is small. It is characterized by little variation.

Claims (1)

[Scope of Claims] 1. A coating layer mainly composed of silicone rubber is formed on the outer periphery of the core metal via a primer layer, and after polishing to almost the final finished outer diameter, this is immersed in silicone oil to remove the above coating. The swelling value of the layer is 40~80
1. A method for manufacturing a heat fixing roller for a silicone oil supply type electrophotographic copying machine, which comprises stopping swelling at a temperature of 1.5%, and then finishing the roller to a predetermined outer diameter. 2. The method of manufacturing a heat fixing roller for a silicone oil supply type electrophotographic copying machine according to claim 1, wherein polishing is performed after primary vulcanization and before secondary vulcanization.