JPS5953548B2 - Fusing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing device for thermally fixing a heat-fusible powder image on a copying material in an electrophotographic copying machine or the like.

More specifically, the present invention relates to a fixing device that is improved so as to constantly supply an appropriate amount of anti-offset liquid to a moving heating element. In recent years, electrophotographic copying apparatuses have shown a trend toward higher speeds.

When fixing electrophotography, the fixing method that supplies heat from a heating element such as an infrared ray, a hot plate, or a ribbon heater to the copying material via a poor conductor of heat such as air has very poor thermal efficiency and requires large equipment. Therefore, the frequency of use is decreasing. Instead of these methods, the heated roller fixing method, which fixes the powder image to the copying material by bringing a heating body into direct contact with the toner powder image, has good thermal efficiency, is highly safe, and requires a small device.
It is becoming more frequent. Conventionally, in a thermal roller fusing device, a certain type of R is applied on the surface of the fusing roller.
By providing a releasable material such as TV (room temperature vulcanization) silicone rubber or by supplying an anti-offset liquid to the surface of the fixing roller, it is possible to offset the powder image from the copying material to the fixing roller and prevent the copying material from wrapping around the roller. We are trying to prevent this. However, the offset prevention performance of RTV silicone rubber rollers deteriorates over time, and in our experiments, the rubber roller surface was heated to 180°C.
After about 400 hours of use in a heated state, the anti-offset ability of the rubber roller decreased to the point where it was no longer practical.

Therefore, after a certain period of time, the rubber roller needs to be replaced.

Therefore, in high-speed copying machines, the replacement frequency is high, which is impractical. In addition, as a method of supplying anti-offset liquid such as silicone oil to the surface of the fixing roller, a conventional method has generally been used in which a heat-resistant felt impregnated with silicone oil is brought into contact with the fixing roller. When the felt comes into contact with the fusing roller, the felt becomes saturated with oil, resulting in an excessive amount of oil being applied to the roller, causing slippage between the rollers, or silicone oil adhering to the copying material, causing damage to the copying material. This caused serious troubles, such as the texture of the surface of the copying material after copying was completed and the ink's compatibility when adding ink to the copying material.

Therefore, in order to prevent over-application, it is necessary to keep the felt in an unsaturated state at all times. The amount of oil in the felt is regulated and overcoating is prevented by appropriately rotating the oil pumping roller so that the oil is supplied to the felt.

1. Also, in order to prevent overcoating when one end of the felt is directly immersed in an oil tank (the felt becomes saturated), conventionally, a plunger or the like is used to move the felt toward and away from the fixing roller as appropriate. This prevents over-application.
1. However, in any of the above cases, a means for blocking the oil transfer path from the oil tank to the fixing roller is required, resulting in a disadvantage that the apparatus becomes large and complex, and control is difficult. The aim of the present invention is to overcome all the drawbacks of the above-mentioned conventional methods.

The present invention has a simple structure and is designed to constantly supply an appropriate amount of anti-offset liquid to the surface of a fixing roller.

That is, the present invention provides a fixing device that fixes a toner image support with a fixing roller, and is provided with a coating device for supplying an anti-offset liquid to the fixing roller, wherein the coating device is provided with a non-absorbing liquid on the coating member. It is characterized by having a liquid control member formed by dispersing and fixing a liquid substance. This is a fixing device with a special feature.

Ming? 1. The fixing device of the present invention will be described in detail with reference to the drawings. Figure 1 shows an embodiment of the present invention, in which 1 is a hollow bolt made of a material with good thermal conductivity such as aluminum or copper. This is a fixing roller in which a tube 2 is thinly coated with a release material 3 such as silicone rubber or Teflon (tetrafluoroethylene resin).

Both rollers 1 and 4 are pressed against each other with appropriate pressure and rotate in the direction of the arrow. A copying material 5C made of paper holding a heat-fusible toner powder image T is conveyed in the direction of the arrow, and is moved to the roller 1.
, 4. The fixing roller 1 is heated by a halogen lamp 7 which is a heat source disposed inside.
At the contact portion with the pressure roller 4, sufficient heat is applied to melt the toner powder image T. Further, the surface temperature of the fixing roller 1 is always controlled within a constant temperature range by a temperature detection element 9 such as a thermistor. 10
is an input guide 11 for conveying the copy material to the rollers,
Reference numeral 12 denotes a separation claw for reliably separating the copy material after fixing, and is made of a heat-resistant, releasing resin such as Teflon, or a metal surface coated with a releasing material such as Teflon, or is in contact with a roller. About 1 mm of the tip is made of a heat-resistant resin with excellent strength, and the other parts are made of a heat-resistant, mold-releasing resin such as Teflon.

Reference numeral 13 denotes an offset prevention liquid storage tank for storing an offset prevention liquid 14 such as silicone oil, and the offset prevention liquid 14 in the tank is supplied to the fixing roller 1 via a coating member 15.

The application member 15 is made of Nomex (high temperature resistant polyamide fiber)
, a heat-resistant and oil-resistant felt such as Teflon (fluorinated ethylene resin fiber),
The anti-offset liquid is absorbed and retained within the felt by capillary action.

The felt 18 is supported by a support plate 20, and the support plate 20 is rotatably supported by a fulcrum 21. A liquid control member 22 for controlling the amount of anti-offset liquid supplied is provided on the surface of the felt 19 applied to the fixing roller 1.

The liquid control member 22 is provided on the surface of the felt 19, as shown in FIG. It is formed by coating with.

For example, after immersing felt in a dispersion of powder such as Teflon, or after applying a dispersion of Teflon powder to felt, the felt is baked at 230°C for 15 minutes to coat the surface and inside of the felt with Teflon powder. Formed by sticking together. Various methods can be selected for fixing the non-liquid-absorbing substance to the felt. The area ratio of felt and non-absorbent material on the felt surface that comes into contact with the fixing roller is 1:
A ratio of 3 to 1:6 is desirable, and by changing this ratio, the amount of anti-offset liquid supplied to the fixing roller can be changed as desired. FIG. 3 shows another embodiment of the present invention, in which a liquid control member 22 is disposed between a felt 18 and an applicator roller 30 made of silicone rubber, and is made of metal, glass, Teflon, metal or It consists of a mesh made of glass coated with Teflon and having a large number of openings, and this mesh is provided in the felt 18. The opening ratio of the mesh is preferably 15% to 35%. Note that punching metal may be used instead of mesh. The amount of anti-offset liquid supplied to the fixing roller can be controlled by changing the aperture ratio of the mesh or punching metal. As described above, according to the present invention, there is no need to provide a means for blocking the movement path of the anti-offset liquid as in the past, and it is possible to supply the necessary minimum amount of anti-offset liquid to the heating element with a simple configuration. The fixing operation is always stable, the amount of anti-offset liquid consumed is small, and it is economically superior.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a fixing device showing an embodiment of the present invention;
FIG. 2 shows an enlarged view of the main part, and FIG. 3 shows a configuration diagram of another embodiment. DESCRIPTION OF SYMBOLS 1... Fixing roller 4... Pressure roller 15... Coating member, 22... Liquid control member.

Claims (1)

[Scope of Claims] 1. A fixing device that fixes a toner image support with a fixing roller, the fixing device being equipped with a coating device for supplying an anti-offset liquid to the fixing roller, wherein the coating device is not attached to the coating member. A fixing device comprising a liquid control member formed by dispersing and fixing a liquid-absorbing substance. 2. The fixing device according to claim 1, wherein the liquid control member is provided in contact with the surface of the fixing roller. 3. The fixing device according to claim 1, wherein the coating means includes a coating roller that supplies the anti-offset liquid to the surface of the fixing roller, and the liquid control member is brought into contact with the coating roller. 4. The fixing device according to any one of claims 1 to 3, wherein the non-liquid substance is an oil-resistant powder and is fixed to the application member by firing.