JPH0743556B2 - Method of manufacturing heat fixing roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a heat fixing roller used in a heat fixing unit of an electronic copying machine or the like.

(Prior Art) Conventionally, as a heat roller or a press roller used in a heat fixing portion of an electronic copying machine, a metal cylinder covered with silicone rubber, fluororubber or the like has been generally used. In order to improve the releasability of the roller from the toner, a silicone rubber material should be impregnated with silicone oil in advance, or a fluororesin layer should be provided on the rubber layer by electrostatic coating or coating with a heat shrinkable tube. Is being done.

Among these rollers, the roller in which the fluororesin layer is provided on the silicone rubber layer is cheaper than the fluororubber roller, and the roller with the toner is better than the roller in which the silicone rubber material is impregnated with silicone oil. It has excellent releasability and is easy to maintain and manage, and is widely used.

(Problems to be Solved by the Invention) In the case of providing a fluororesin layer by powder electrostatic coating, in order to make the coating into an integrated film after spraying the powder coating,
A firing process is required. Therefore, there is a problem that the rubber layer as the base layer is exposed to a high temperature during the firing process and may be deteriorated. On the other hand, in the method of coating the heat-shrinkable tube, after the tube is coated, hot air is blown to shrink the tube and bring it into close contact with the rubber layer, so that the rubber layer is less likely to deteriorate than in the case of powder. However, since it is difficult to uniformly heat and shrink the tube, there is a problem that the film thickness becomes non-uniform and undulation is likely to occur on the surface of the tube after shrinking.

That is, for example, PTFE (polytetrafluoroethylene)
Although the dispersion was fired at around 380 ° C for several tens of minutes, deterioration of the rubber layer was unavoidable under such heating conditions.

The present invention has been made to solve such conventional problems, and an object thereof is to provide a method of manufacturing a heat fixing roll capable of firing a coating layer by a fluororesin dispersion without deterioration of a comb layer. To do.

[Structure of the Invention] (Means for Solving Problems) That is, in the method for manufacturing a heat fixing roller of the present invention, a rubber layer is formed on the outer periphery of the roller core shaft, and a fluororesin film is formed on the rubber layer. In this regard, a fluororesin dispersion is coated on the rubber layer, and after preliminary drying, the coated surface is brought into pressure contact with a heating body heated to a temperature equal to or higher than the melting point of the fluororesin, and the heating body is heated. It is characterized in that the surface or the coated surface is rolled to heat.

The fluororesin dispersion used in the present invention includes PTFE dispersion as well as PFA (perfluoroalkyl vinyl ether) dispersion at 300 ° C.
Those using a fluororesin having the above heat resistant temperature are suitable.

The preliminary drying in the method of the present invention is for removing the water and the surfactant on the coated surface prior to firing, and any heating means can be adopted.

A heating roll is suitable as the heating element in the present invention, but a flat heating element such as an endless belt can be used as long as the rubber roller can be rolled on it. The heating temperature of the heating element is preferably in the range of 360 ° C to 550 ° C (preferably 400 ° C to 450 ° C) when using, for example, PTFE dispersion.

The film-forming property can be improved by economically increasing the contact pressure between the heating element and the roller to be fired.

Table 1 shows the relationship between the three illustrated pressure increase patterns and the film forming property.

As shown in Table 1, when the contact pressure increase rate is increased with time as in the pattern C, the film forming property becomes very good and voids are not seen.

On the contrary, when the pressure is applied all at once immediately after the start of the pressure contact as in the pattern A, the film forming property is deteriorated because the fluororesin adheres to the high temperature heating body and the applied surface is disturbed. Conceivable.

(Example) Hereinafter, the Example of this invention is described.

Example P on silicone rubber roller (diameter 40mm, roller length 330mm)
After applying TFE dispersion, according to the method of the present invention, about 100 ℃ 10 minutes, then 250 ℃ 20 minutes pre-drying is performed to remove water and surfactants, then 400-450.
Roller heating element heated to ℃ (diameter 40 mm, roller length 34
(0 mm) for one round, and the surface of this heating body was rolled and pressed under heating contact, whereby a heat fixing roller having a good film-forming property and a good adhesive property with a rubber layer was obtained.

Table 2 shows the relationship between the presence or absence of pressure during firing and the adhesiveness.

As is clear from this table, the heat fixing roller heated by being brought into pressure contact also had good adhesiveness between the rubber layer and the PTFE coating.

In this example, as the PTFE and the dispersion, three kinds of commercially available products whose physical properties are shown in Table 3 were used, and similar results were obtained in all cases.

Although PTFE is used as the fluororesin in the above examples, the present invention is not limited to this and PFA or the like can also be used.

EFFECTS OF THE INVENTION As described above, according to the method for manufacturing a heat fixing roller of the present invention, it is possible to uniformly form a thin fluorine layer resin film firmly adhered to the rubber layer, so that the releasability from the toner is improved. -It is possible to manufacture heat fixing rollers of excellent quality that have excellent paper passing properties, good heat fixing efficiency, and long product life.

[Brief description of drawings]

The drawing is a graph showing the relationship between the contact pressure between the roller and the heating body and time.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayoshi Murakami 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Showa Electric Wire & Cable Co., Ltd. (72) Toshimitsu Iwata 2 Sadae Oda, Kawasaki-ku, Kanagawa No. 1-1 No. 1 Showa Electric Wire & Cable Co., Ltd. (56) Reference JP 62-191130 (JP, A) JP 62-200381 (JP, A) JP 62-21162 (JP, A) Special Kai 62-227463 (JP, A) JP 62-23179 (JP, A) JP 57-89785 (JP, A)

Claims (2)

[Claims] 1. A rubber layer is formed on the outer circumference of a roller core shaft, and a fluororesin coating is formed on the rubber layer. After the fluororesin dispersion is coated on the rubber layer and pre-dried, Heat of the fluororesin coating characterized in that the coated surface is brought into pressure contact with a heating body heated to a temperature equal to or higher than the melting point of the fluororesin, and the surface of the heating body or the coated surface is heated by rolling. Method of manufacturing fixing roller. 2. The method for producing a heat fixing roller according to claim 1, wherein the temperature of the heating element is 360 ° C. to 550 ° C.