JPS61158361A - Heat roller for fixing of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To obtain the titled roller having excellent nonadhesiveness of the roller surface for a toner, capable of obtaining distinctness of the printed image, and without generating any cracks or stripping by forming the roller with an elastic layer consisting of silicone rubber, an intermediate layer obtained by curing and binding a mixture of fluororubber and fluororesin, and the surface layer of the roller obtained by calcining and binding a PFA resin. CONSTITUTION:An elastic layer 2 consists of silicone rubber formed and fixed on a core metal 1, and an intermediate layer 3 is obtained by mixing fluororubber and fluororesin in 95/5-50/50 weight ratio, and curing and binding the mixture onto the elastic layer 2. The surface layer 4 of the roller is obtained by calcining and binding a PFA resin in <=100mu thickness onto the intermediate layer 3. The silicone rubber having about 20-50 deg. rubber hardness and having high heat resistance enough to resist the temp. of calcination of the PFA resin to form the surface layer of the roller 4 is required as the silicone rubber of the elastic layer 3. The intermediate layer 3 is interposed between the elastic layer 2 and the surface layer 4 of the roller to bridge both layers.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the Invention) The present invention relates to an improvement of a fixing heat roller for an electronic copying machine. The object of the present invention is to provide a heat roller for fixing which does not cause cracks or flakes on the surface of the roller.

For fixing toner print images in electronic copying machines, a set of a heated roller and a pressure roller that are circumferentially circumferentially connected with a constant nip radius is widely used. In order to prevent toner from remaining on the roll surface of the heat roller and causing offsets, non-adhesive materials such as silicone rubber and fluororesin have been widely used for the layer forming this surface. However, those that use silicone rubber for the layer forming the roll surface,
Since the silicone rubber has appropriate soft elasticity, the fixed toner III image is clear, but there is a drawback that it is somewhat lacking in non-adhesion to toner. On the other hand, those made of fluororesin have excellent non-adhesive properties, but because of the high hardness of the fluororesin, they tend to cause three-knobs when feeding the paper, and the print image lacks clarity. .

In order to deal with these circumstances, recently, fluorinated resin tubes have been coated on the elastic layer made of silicone rubber as an O-ru surface, and instead of coating fluorinated ileal tubes, fluorinated resin paint has been baked. It has also been proposed to use fluororubber for the elastic layer and a composite rubber made by adding aminosilane to fluororubber and fluororesin for the roll surface layer.

However, for coated fluorine-N resin tubes, it is difficult to process thin tubes, and so far it has not been possible to obtain tubes with a wall thickness of less than 200 μm. It has the disadvantage of high altitude. 1 due to baking of fluorine 8I fat paint
Although it is possible to obtain a roll surface layer made of a fluororesin with a diameter of 00 μm or less, the adhesion to the silicone rubber that forms a good elastic base layer is not good, so cracks and interlayer peeling due to fatigue tend to occur. Furthermore, when using the composite rubber as described above for the roll surface layer, it is necessary to incorporate various inorganic fillers in order to maintain the strength, and therefore, a decrease in non-adhesiveness is unavoidable.

(Structure of the Invention) The present invention has been made in order to eliminate the above-described drawbacks regarding the formation of the roll surface layer of the heated roller in the constant roller of an electronic copying machine, and the present invention will be described below with reference to the illustrated embodiments. That is, 2 is an elastic layer made of silicone rubber molded and fixed onto the core metal 1. 3 is the middle layer, which contains 95:5 to 50:5 of fluororubber and fluororesin.
The mixture was mixed at a weight ratio of 0 and hardened and bonded onto the elastic layer 2. 4 is the O-Ra surface layer, and P is on the intermediate layer 3.
FA [fat is baked and bonded to a thickness of 100 μm or less.

Silicone rubber with elasticity R1J2 has a rubber hardness of 2.
The roller surface layer 4 is made of PFAN resin at about 0° to 50″.
A material with high heat resistance is required to withstand the firing process used to form the material. The intermediate layer 3 includes the elastic layer 2 and the roller surface layer 4.
When forming the O-lar surface layer 4, firing is performed at a slightly higher temperature than 300 to 310°C, which is the melting point of PFAar resin. , when the mixture of fluororubber and fluororesin is in a liquid state, as shown in FIG.
The fluororubber component 31 gathers on the heat-receiving side, which is the upper side in the figure, while a large amount of the fluororubber component 31 gathers on the elastic layer 2 side. In this case, fluoride! Naturally, the fat component 32 of 11 is strongly fused to the roller surface layer 4 made of PFAN fat, while the fluororubber component 31 has a high affinity for the silicone rubber of the elastic layer 2, so the intermediate layer 3 is Surface layer 4 and elastic layer 2
to form a strong bridging bond. That is, when the releasability of the roller surface layer 4 of the O-Lar according to the manufacturing example described below was examined by a tensile test, the roller surface ff14 could not be peeled off from the elastic layer 2, and the elastic layer was destroyed at that time. The reason why the weight ratio of the mixture of fluororubber and fluororesin in the intermediate layer 3 was set at 95:5 to 50:50 is that if the fluororesin is less than 5%, the bonding with the roller surface layer is insufficient.
Moreover, if it exceeds 50%, the bondability with the elastic layer 2 will be insufficient. Furthermore, if the wall thickness of the a-lar surface rib 4 made of PFAaN resin exceeds 100μ, even if silicone rubber with low rubber hardness is used for the elastic layer 2, the effective hardness of the 0-lar will be high, and therefore, the toner image will be Since the sharpness of the roller is lost, the thickness of the roller surface layer when the roller is completed is 1
Must be less than 00μ.

As mentioned above, the effect of interposing the intermediate layer 3 is that it serves as a strong bridging bonding medium between the roller surface layer 4 and the elastic layer 2. PFAaM when firing the roller surface R34 made of PFAN resin or when using the finished roller product in a copying machine.
Another notable effect of the intermediate layer 3 is that it alleviates the thermal fatigue of the fat and prevents the occurrence of cracks. This means that the thermal expansion coefficient of silicone rubber is 2~10XlO-4/℃, PFAJ
The coefficient of thermal expansion of lt fat is 1.2Xlo'/'C, while fluororubber and fug! , the coefficient of thermal expansion of MM fat in the above mixing range is 1, which is between them.
It will be well understood from the fact that 5~a, ox to '/'c.

(Manufacturing example) Outer diameter 38.92 layers 1 Length 300 layers, iron core 1
An elastic W! made of silicone rubber (YJX-34-062, manufactured by CJ Etsu Silicone Co., Ltd.) is attached to the mandrel 1. J2
mold. Next, apply "fluororubber paint" on the elastic core 2.
A mixture of fluororubber and fluororesin (Daikin Industries, Ltd. +1; LS-213) was coated to a thickness of 20 μm and dried 8 m. It was painted, baked at 340"C for 10 minutes, and polished to form a roller with a diameter of 40 ml.

(Effects of the Invention) Thus, according to the present invention, since the roller surface layer 4 is formed of a fluororesin, it is naturally excellent in non-adhesiveness, and since the thickness of the fluorine M fat in the roller surface layer 4 is small, it is effective. The hardness is small and the soft elasticity of the silicone rubber of the elastic layer 2 is not lost, so the toner image after fixing is clear.

Since the elastic layer 2 and the a-ra surface layer 4 are firmly connected by the middle 8-fu 3, no nrJJ flakes occur and no
- Despite the thinness of the roller surface layer 4, no thermal fatigue or cracks occur during the flIa process or during use, and therefore the roller has a long service life.

Therefore, the present invention significantly contributes to improving the performance of electronic copying machines.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the heat roller according to this invention, Figure 2
The figure shows the heat zero to explain the bridging bond between the roller surface layer and the elastic layer.
- is a partial axial cross-sectional view of the roller. 1 is a core metal, 2 is an elastic layer, 3 is an intermediate layer, 31 is a fluororubber component, 32 is a fluororesin component, 4 is a roller surface layer, and 5 is a heater.

Claims (1)

[Claims] The elastic layer 2 made of silicone rubber molded and fixed on the core 1 has a ratio of 95:5 to 50: of fluororubber and fluororesin.
An electronic roller consisting of an intermediate layer 3 in which a mixture of 50% by weight is hardened and bonded onto an elastic layer 2, and a roller surface layer 4 in which a PFA resin is baked and bonded to the intermediate layer 3 to have a thickness of 100μ or less. Heat roller for fusing in copying machines.