JPH0135348B2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention is based on a plain paper copy.
Copy) (PPC) This relates to a device that applies a release agent such as silicone oil to the fixing roll of a copying machine.

(Prior art and its problems) Basically, the fixing mechanism in a PPC copying machine is to pass the toner transferred onto the paper between a heated fixing roll and an elastic pressure roll such as a rubber roll while applying heat. It consists in crimping and baking. In such a mechanism, when a paper surface with toner attached passes between a heated fixing roll and an elastic pressure roll, the paper itself adheres to the roll and wraps around the roll, preventing complete printing. Problems such as toner transferred to the copy paper adhering to the fixing roll, resulting in double copies of the image (so-called offset phenomenon) and equipment failure, occur.
Therefore, various studies have been made in the past regarding this point, but the final method has been to apply a mold release agent to the fixing roll and the elastic roll for mold release.

However, it is very difficult to apply this mold release agent evenly and in the right amount to the roll, and if too much mold release agent is used, the paper surface becomes stained or discolored, and at the same time, the mold release agent is consumed rapidly. It takes time and effort to lubricate the roll, and too much mold release agent can solidify on the roll surface, causing unexpected breakdowns. Furthermore, if the amount of release agent is too small, the above-mentioned offset phenomenon will naturally occur, and the release properties of the roll surface will deteriorate, causing the paper to wrap around the roll. Incidentally, heat-resistant oil such as silicone oil is mainly used as a mold release agent.

For this reason, conventional release agent applicators with various structures have been developed and proposed, but these are not necessarily sufficient.

Therefore, the applicant of this patent has developed a mold release agent applicator that is economical, ensures uniform application of mold release agent, consumes the minimum amount of mold release agent, and can be installed even in extremely narrow spaces. In addition, he invented and applied for a patent on the following product, which has a simple shape, is very inexpensive, and is disposable.

That is, as shown in FIGS. 1 and 2, the toner image is passed between the fixing roll 14 and the pressure roll 15 on the copy paper 16.
A fixing roll 14 in a fixing device that heats and fixes
A porous tetrafluoroethylene resin tube 7 whose both ends are heat-pressed or sealed with a plug is brought into contact with the generatrix direction of the roll, and a mold release agent 6 is applied with the porous tetrafluoroethylene resin tube. It is characterized by making it do so.

In the above case, since the porous tube 7 is soft, it is supported by the support 1 (FIG. 1) or 4 (FIG. 2). Further, in the porous tube, the pores other than the necessary openings from which the mold release agent is leached are filled with fluororubber or other material by, for example, coating. This is to make the discharge amount of the mold release agent a predetermined amount and uniform. Furthermore, a mold release agent is placed in the porous tube either beforehand or afterward.

In Figures 1 and 2, 2 is a closed portion of the porous tetrafluoroethylene resin tube, 3 is an open hole of the porous tetrafluoroethylene resin tube, and 5 is an injection port.

However, even with the above, the following problems still exist. That is, it is necessary to close the pores of the porous tube other than the exudation part.

(Structure of the Invention) In view of this point, the present inventor invented a mold release agent coating device that can perform this process more easily, and filed a patent application on the same day as the present application.

That is, by using a divided support that forms a lumen with an opening whose width is smaller than the maximum width of the lumen, the supports are combined, both ends are sealed, and a mold release agent is placed inside; or A porous tube of tetrafluoroethylene resin to be inserted is held in the inner cavity with the part that will become the mold release agent leaching part protruding from the opening, and the part that will become the mold release agent leaching part that protrudes from the opening of the porous tube. This is a release agent applicator in which the pores in the other parts are closed by contact between the porous tube and the inner wall of the support body.

As mentioned above, this device is extremely excellent as a mold release agent applicator, and the device in which the mold release agent is pre-filled can be disposable. However, the only drawback is that the amount of mold release agent applied is not constant.

The present invention was developed to solve this problem as well, and in the mold release agent application device of the patent application filed on the same date, a porous tube of tetrafluoroethylene resin is coated with a pore size that is smaller than the diameter of the pores. The first feature is that an air intake port with a large pore diameter is provided in the porous tube and the support so that air can be taken into the porous tube. The air intake is on the opposite side of the porous tube from the protruding portion.

As a result of the above, there is little change in the amount of the release agent applied over time.

Furthermore, a second feature of the present invention is that the air intake port of the porous tube and the air intake port of the support plate are provided at different positions.

The above prevents the release agent in the tube from leaking out due to thermal expansion or the like when the tube is set in the fixing device.

The present invention will be explained in detail below with reference to the illustrative drawings.

Figures 3 and 4 show the mold release agent application device of the present invention,
20 indicates a porous tube of tetrafluoroethylene resin, which is obtained by extruding a tetrafluoroethylene resin mixture containing a liquid lubricant into a tube shape, stretching it, and then sintering it. No. 13560 and Japanese Patent Application No. 50-155226, the micropores have a uniformly controlled pore size, preferably have a pore size of 0.1 to 10 μm, have a porosity of 50 to 85%, and an outer diameter of 5 to 50 μm.
A polytetrafluoroethylene resin porous tube having a structure with a wall thickness of 0.1 to 5 mm is used, for example, a pore front tube manufactured by Sumitomo Electric.

21 is a support which is divided into two parts. The third rate
It may be divided into upper and lower sections as shown in the figure, or it may be divided into left and right sections as shown in FIG. The support body 21 is a porous tube 2
The maximum width B of the lumen 22 that encloses the 0 is larger than the width A of the opening 23 from which the release agent exudation part of the porous tube projects (A<B). As a result, the support closes the pores in the portion of the porous tube other than those protruding from the opening, and at the same time supports the porous tube.

In the above, the air intake port 24 has a diameter larger than the pore diameter of the porous tube, for example, 2 to 3 mmφ,
25 are a porous tube 20 and a support 21 in advance, respectively.
It is provided in It is preferable that the large-diameter air intakes be provided at different positions, especially in the longitudinal direction. When the above positions are shifted, the groove 26 extending from the air intake port 25 of the support body to the air intake port 24 of the porous tube is, for example, a 3 to 4 mm wide groove on the support body 2.
1.

According to the above method, since air is introduced into the porous tube through the large-diameter air intake port, it is possible to obtain a product in which the amount of applied mold release agent does not change significantly over time, as shown in the experimental examples described later. Also, if the large diameter air intake port is placed at a different position between the porous tube and the support, the grooves provided in the support between them will prevent release agent from escaping from the tube due to thermal expansion when set in the fixing machine. It provides a place to escape and returns to the inside of the tube along the groove, preventing the release agent from leaking to the outside.

Experimental examples of the present invention will be described below. Put 30,000 CS of silicone oil into the Sumitomo Electric pore front tube. The difference in the amount of oil applied when the air intake hole is not made and when it is made is shown in Figures 6 and 7. Incidentally, the amount of oil discharged was determined by checking the change in the overall weight of the coating device using the fixing machine shown in FIG. In Fig. 5, 27 is an oil application device, 28 is a blade, 29 is a peeling claw, 14 is a fixing roller (heating temperature 180°C), 1
5 is a rubber pressure roller, 16 is a copy paper, and 19 is a toner.

In the case without air holes as shown in FIG. 6, the internal pressure increases due to initial oil expansion, resulting in a large discharge amount, and as time passes, the pressure inside the tube decreases and the discharge amount decreases.

When there are air holes as shown in Fig. 7, the amount of oil discharged is a little high at the beginning, but it soon stabilizes.

(Effects of the Invention) As described above, the porous tube according to the present invention is supported by the support and at the same time, by contact thereof, the pores in the porous tube other than the release agent leaching part can be easily closed. In the mold release agent application device, a uniform amount of mold release agent can be obtained regardless of the passage of time.

Furthermore, when the air intake port is shifted in position between the tube and the support and a groove is provided between them on the support side, it is possible to prevent the release agent from leaking to the outside.

[Brief explanation of drawings]

Figures 1 and 2 illustrate explanatory diagrams of the mold release agent application device developed earlier by the present inventor, where Figure 1 is a front view (Figure a) and cross-sectional view (Figure b), and Figure 2 is a front view. It is a diagram.
3 and 4 illustrate explanatory diagrams of the mold release agent application device of the present invention, FIG. 3 is a cross-sectional view (Figure a) and a plan view (Figure B), FIG. The figure is an explanatory diagram of the apparatus used in the experimental example of the present invention, and Figures 6 and 7 are explanatory diagrams of the experimental example of the present invention. Examples are shown in which the porous tube has an air intake port. DESCRIPTION OF SYMBOLS 1...Support, 2...Closed part of tetrafluoroethylene resin porous tube, 3...Opening part of tetrafluoroethylene resin porous tube, 4...Support, 5...Inlet, 6
...Mold release agent, 7.Tetrafluoroethylene resin porous tube, 14..Fixing roll (heating roll), 15..Elastic pressure roll, 16..Copy paper, 19..Toner, 2.
0...Tetrafluoroethylene resin porous tube, 21...
Support, 22...Inner cavity, 23...Opening, 24,2
5...Air intake port, 26...Groove, 27...Oil applicator, 28...Blade, 29...Peeling claw.

Claims (1)

[Scope of Claims] 1. Using a divided support body forming a lumen with an opening in which the width A of the opening is smaller than the maximum width B of the lumen part, the support bodies are combined and both ends are sealed and the interior is sealed. A polytetrafluoroethylene resin porous tube containing or containing a mold release agent is held in the inner cavity with the part that will become the mold release agent leaching part protruding from the opening, and the tube is made to protrude from the opening of the porous tube. In the case where the pores in the part other than the part that becomes the release agent leaching part are closed by the contact between the porous tube and the inner wall of the support, an air vent with a pore diameter larger than the pore diameter of the porous tube is used. A mold release agent coating device for a copying machine, characterized in that an inlet is provided in a porous tube and a support so that air can be taken into the porous tube through an air intake port having a large pore diameter. 2 Using a divided support that forms a lumen with an opening where the width A of the opening is smaller than the maximum width B of the lumen, the supports are combined, both ends are sealed, and a release agent is placed inside. A porous tube of tetrafluoroethylene resin is held in the inner cavity with the part that will become the release agent leaching part protruding from the opening, and the part that will become the release agent leaching part that protrudes from the opening of the porous tube. In a device in which the pores in other parts are closed by contact between the porous tube and the inner wall of the support body, the air intake port with a pore diameter larger than that of the pores in the porous tube and the support body is closed. 1. A release agent coating device for a copying machine, characterized in that the release agent applicator is provided in a porous tube at a shifted position so that air can be taken into the porous tube through an air intake port having a large hole diameter. 3. A release agent coating device for a copying machine according to claim 2, wherein a groove is provided in the support from the air intake of the support to the air intake of the porous tube. 4. A release agent coating device for a copying machine according to claim 2, wherein the air intake port of the support body and the air intake port of the porous tube are provided with positions shifted in the longitudinal direction.