JPH0743559B2 - Method of manufacturing heat fixing roller - Google Patents

Description

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

(Prior Art) Conventionally, as a heat fixing roller used in a heat fixing section of an electronic copying machine or the like, a silicone rubber material is coated on a metal core shaft made of aluminum or the like, and toner is further coated on the silicone rubber layer. It is known that a polytetrafluoroethylene resin (hereinafter referred to as PTFE) dispersion is applied and baked to provide a PTFE layer in order to improve the releasability.

And as a method of applying PTFE dispersion,
Methods such as spraying, flowing down, brush coating, electrostatic coating of PTFE dispersion are performed.

By the way, when the heat fixing roller is actually used, since the separation claws are in contact with the surface and a nip is formed between the heat fixing roller and the pressure roller to cause friction, the outermost PTFE layer is uniform and mechanical. It is required to have excellent mechanical properties such as dynamic strength and elongation.

That is, if these properties are insufficient, for example, this PTFE layer is ruptured and the base silicone rubber layer is exposed, the releasability with the toner and the paper passing property are impaired, and separation occurs at the cracked portion. There is a risk that the nail may be caught and peel off the film.

(Problems to be solved by the invention) However, in the conventional method, it is difficult to apply the PTFE dispersion uniformly and in a state where the PTFE particles are densely arranged, and the melt viscosity of PTFE is high, Since the fluidity cannot be expected, there is a problem in that a uniform and excellent PTFE mechanical layer cannot be formed.

Furthermore, the spraying method tends to cause clogging in the spray, and the electrostatic coating method causes the PTFE
There is also a problem that the dispersion efficiency is low because the dispersion is water-based.

Therefore, the present invention is intended to solve such conventional problems, a predetermined amount of PTFE dispersion can be uniformly applied to the surface of the silicone rubber layer, and therefore a uniform and excellent PTFE mechanical layer is obtained. An object of the present invention is to provide a method for manufacturing a heat fixing roller that can be easily formed.

[Structure of the Invention] (Means for Solving the Problems) (a) A silicone rubber roller provided with a silicone rubber layer on the outer periphery of a core shaft is inclined at a predetermined speed with the silicone rubber layer slightly inclined with respect to a horizontal plane. The step of making the polytetrafluoroethylene resin dispersion adhere to the surface of the silicone rubber layer by immersing it in a dipping tank containing the polytetrafluoroethylene resin dispersion while rotating it with (b) this polytetrafluoroethylene resin dispersion A step of applying the polytetrafluoroethylene resin dispersion uniformly on the surface of the silicone rubber layer by idly rotating the adhered silicone rubber roller at a predetermined speed, and (c) Polytetrafluoroethylene resin dispersion on the surface of the silicone rubber layer. The steps of drying and baking It is characterized by doing.

In the present invention, in order to apply the PTFE dispersion more uniformly on the silicone rubber layer, a liquid level adjusting means for finely adjusting the height of the liquid level in the dipping tank is provided,
It is preferable that the idle rotation speed of the roller after the immersion is slower than the rotation speed during the immersion.

Incidentally, as the PTFE dispersion of the present invention, AD-639
Various known PTFE dispersions commercially available (such as Asahi Glass Co., Ltd.) can be used.

(Operation) In the present invention, by holding the silicone rubber roller with a slight inclination in the same direction, and by continuing to rotate the silicone rubber roller for a while even after the immersion of the PTFE dispersion, the surface of the silicone rubber layer is Appropriate amount of PTFE dispersion is evenly applied.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view schematically showing a coating process of PTFE dispersion, which is a feature of the present invention.

In the figure, reference numeral 1 denotes a silicone rubber roller having a crown-shaped silicone rubber layer 1b provided on the outer periphery of the core shaft 1a, which is rotated at a predetermined rotation speed around the core shaft 1a in a state of being inclined at a minute angle θ. It is held by the device.

The reason why the silicone roller 1 is held at a slight angle in this way is that the silicone roller is generally formed in a crown shape in which both ends are slightly swollen compared to the central part in order to obtain a uniform surface pressure. Often, therefore, such a silicone rubber roller 1 has two crown surfaces.
This is because the liquid draining property is improved by holding 1c so as to be inclined in the same direction with respect to the horizontal plane.

FIG. 2 is a view in which the inclination of the silicone rubber roller 1 is slightly exaggerated. Silicone rubber roller 1
If the entire silicone rubber roller 1 is inclined so that the tangent line l ₀ at the end of the right crown surface 1c in FIG. All of them move to the left in the figure, and therefore by attaching an appropriate liquid draining guide 5 to the left end of the silicone rubber roller 1, smooth liquid draining can be performed.

The immersion tank 3 containing the PTFE dispersion 2 is arranged below the silicone rubber roller 1 held in this way. A liquid level adjusting flexible tube 4 having a tip fixed to an elevating device is connected to the side surface of the immersion tank 3, and the tip of the liquid level adjusting flexible tube 4 is moved up and down by the elevating device. By moving it, the liquid level of the PTFE dispersion 2 in the dipping tank 3 can be finely adjusted.

In this embodiment, however, first, the silicone rubber roller 1 is rotatably held on the dipping tank 3 by a slight angle θ, and the dipping tank 3 is driven while rotating at a constant rotation speed (not shown). And the silicone rubber roller 1 is dipped into the PTFE dispersion 2 and then rotated at least once to adhere the PTFE dispersion 2 to the entire surface of the silicone rubber roller 1.

At this time, the tip of the liquid level adjusting flexible tube 4 is raised to a higher position by an elevating device.

Next, the tip of the liquid level adjusting flexible tube 4 is gently lowered to gently lower the liquid level of the dipping tank 3, and the silicone rubber roller 1 is pulled up from the PTFE dispersion 2. At this time, the liquid level is first adjusted. The height of the liquid surface is gradually lowered little by little by the adjusting pipe 4, so that the liquid gradually separates from the surface of the silicone rubber roller 1 to the left side in the figure along the inclined surface. This is to prevent uneven coating due to the liquid pool.
The moment the silicone rubber roller 1 separates from the liquid surface, the liquid draining guide 5 drains the liquid.

After that, the rotation speed of the silicone rubber roller 1 is reduced to about half of the initial speed, and the rotation is continued for several minutes. During this period, the coating layer is made uniform by the surface tension of the coating liquid, and the coating unevenness that appears as spiral streaks is completely prevented.

The silicone rubber roller 1 thus coated with the PTFE dispersion 2 is dried and fired by a conventional method to produce a heat fixing roller.

The following table shows the PTFE of the heat fixing roller obtained by this example.
The tensile strength and elongation of the layer are compared with a PTFE layer formed by a conventional spraying method. The silicone rubber roller used in the examples was a roller having an outer diameter of 60 mm and a length of 320 mm, and AD-639 was used as a PTFE dispersion.
Still another condition is that the rotation speed of the roller during immersion is 3 rpm,
The rotation speed was 5 times, the rotation speed after immersion was 1.5 rpm, and the rotation time was 2 minutes.

Regarding the uniformity of the PTFE layer, when the silicone rubber roller 1 was held horizontally and rotated and immersed only in the PTFE dispersion, there was variation in the range of 10 to 37 μm, whereas the film according to this example The thickness was 19 to 25 μm and showed excellent uniformity.

[Effects of the Invention] As described above, according to the present invention, since it is possible to uniformly apply an appropriate amount of PTFE dispersion to the surface of a silicone rubber roller, it is possible to form a PTFE layer that is uniform and has excellent mechanical properties. It is possible to obtain a high-quality and high-performance heat fixing roller having excellent durability.

[Brief description of drawings]

FIG. 1 is a side view for explaining an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the roller shown in FIG. 1 …… Silicone rubber roller 1a …… Core shaft 1b …… Silicone rubber layer 1c …… Crown surface 2 …… PTFE dispersion 3 …… Immersion tank 4 …… Liquid level height adjustment pipe 5 …… Liquid cutting guide

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Fukahori 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Showa Cable Denki Co., Ltd. (56) Reference JP-A-57-89785 (JP, A) JP 61-124974 (JP, A) JP 63-8777 (JP, A) JP 63-34575 (JP, A) JP 63-113577 (JP, A)

Claims (4)

[Claims] (A) A silicone rubber roller provided with a silicone rubber layer on the outer periphery of a core shaft is made of polytetrafluoro while the silicone rubber layer is slightly inclined in the same direction with respect to a horizontal plane and is rotated at a predetermined speed. A step of immersing it in a dipping tank containing an ethylene resin dispersion to attach the polytetrafluoroethylene resin dispersion to the surface of the silicone rubber layer, and (b) a predetermined silicone roller to which the polytetrafluoroethylene resin dispersion is attached. And a step of uniformly coating the surface of the silicone rubber layer with the polytetrafluoroethylene resin dispersion by spinning at a speed of, and (c) a step of drying and firing the polytetrafluoroethylene resin dispersion on the surface of the silicone rubber layer. Thermal fixing characterized by sequentially performing Method of manufacturing over La. 2. A method of manufacturing a heat fixing roller according to claim 1, wherein the silicone rubber layer is provided in a crown shape on the outer circumference of the core shaft. 3. The method for manufacturing a heat fixing roller according to claim 1, wherein the immersion tank is provided with liquid level adjusting means for finely adjusting the height of the liquid level. 4. The method for producing a heat fixing roller according to claim 1, wherein the idle rotation speed of the roller after immersion is set lower than the rotation speed during immersion.