JPH03267977A - Production of fluororesin coated roll - Google Patents

Abstract

PURPOSE:To improve the adhesion of a fluororesin tube to a metallic core shaft by coating the core shaft with an oxide film formed on the surface by heating in the air with the fluororesin tube, heating and melt-bonding the tube by irradiation with IR from the vicinity of the surface of the tube. CONSTITUTION:A metallic core shaft 4 with an oxide film formed on the surface by heating in the air is coated with a fluororesin tube 3 and this tube 3 is heated and melt-bonded by irradiation with IR 1 from the vicinity of the surface of the tube 3. By this heating at a high temp., oil, hydroxide, etc., sticking to the surface of the core shaft 4 can be nearly perfectly removed and the oxide film formed on the surface of the core shaft 4 ensures a great affinity for the tube 3, accordingly the adhesion of the tube 3 to the core shaft 4 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a fluororesin-coated roller suitable for use as a fixing roller in a fixing device of a copying machine.

(Prior art) Conventionally, the heat fixing rollers and pressure rollers in electronic copying machines, and the elastic rollers used in laser beam printers, etc., have been coated with a fluororesin that has good releasability from toner. are often used, and one of them is one in which the core shaft is covered with a cylindrical tube made of fluororesin and having a thickness of several tens to hundreds of micrometers.

The manufacturing method for such rollers is to coat a metal core shaft with a primer, cover it with a tube made of PFA (perfluoroalkoxy) resin or PTFE (polytetrafluoroethylene>tM resin), and then coat the primer with a primer. A common method is to place the material in a constant temperature bath, heat it, and fuse it.

However, with this method of heating using a thermostatic oven, it is difficult to heat the rollers uniformly due to the unevenness of heating temperature within the thermostatic oven. This creates a problem in that the adhesion between the two deteriorates. In order to improve adhesion, pretreatments such as blasting the metal core shaft and coating with a primer have been carried out, but sufficient adhesion has not yet been achieved. In addition, heating using a constant temperature bath requires heating time of 2 hours or more and increases power consumption, which is not economical, and requires temperature control, which has the disadvantage of extremely low production efficiency.

(Problems to be Solved by the Invention) In view of the above points, the present invention provides a roller coated with a fluororesin tube, in which the fluororesin tube is completely fused to the core shaft, and the adhesion to the core shaft is strong. Another object of the present invention is to provide a method for manufacturing a fluororesin-coated roller with high production efficiency and shortening the heating time required for fusion.

(Means for Solving the Problems) In other words, in the present invention, when a fluororesin tube is coated on a metal core shaft and then heat-fused, the metal core shaft is heated in the atmosphere to oxidize the surface in advance. The present invention relates to a method for producing a fluororesin-coated roller, which is a metal core shaft on which a coating is formed, and the fluororesin-coated roller is heated and fused by irradiating infrared rays from near the surface of the hindlimb tube covered with the fluororesin tube.

In the present invention, an oxide film is formed in advance on the surface of a metal core shaft made of iron, stainless steel, aluminum, or the like. The oxide film can be formed by heating the metal core shaft in the atmosphere at a temperature of about 300° C. or higher. The heating temperature and time conditions may be appropriately set in consideration of the type of metal, the adhesive strength with the tube, the deterioration of the surface of the metal core shaft, etc.

Fluororesin tubes used in the present invention include PFA, PTFE, and tetrafluoroethylene-hexafluoropropylene copolymer (FEP), which have good releasability from toner and good flexibility.
There are heat-shrinkable and non-heat-shrinkable tubes made of fluororesin. In addition, colored tubes are made of a composition in which these fluororesins are pre-mixed with appropriate pigments (colorants such as red, green, and blue, as well as inorganic fillers such as various metal oxides and carbon black) and uniformly dispersed. can also be used. These tubes have a thickness of several tens of microns to approximately 200 microns
It is preferable to use μ. It is also preferable to use a material whose inner peripheral surface has been roughened in advance by etching, since the adhesion to the core can be further improved.

In the method of the present invention, the above metal core shaft is coated with a fluororesin tube and then heated and fused by irradiation with infrared rays. The wavelength range of the infrared rays to be irradiated is near infrared rays or middle infrared rays, and is about 1 to 25 μm.
is within the range of This is because the absorption band of a colorless and transparent fluororesin tube is around 7 to 11 μm, and the absorption band of the metal core shaft and colored tube is in the near-infrared range, so at least one of the objects to be heated that has these absorption bands is This is a slant that emits infrared rays of the corresponding wavelength.

In the present invention, a fluororesin tube is coated directly or via a primer on the metal core shaft 4 which has been heated in the air at a temperature of about 300° C. or more to form an oxide film on the surface.
For example, as shown in the drawing, a heating furnace 2 has a near-infrared lamp 1 placed near the surface of a fluororesin tube 3.
After supporting the pigment in the pigment, the near-infrared lamp 1 is energized to irradiate the surface of the fluororesin tube 3 with near-infrared rays to heat the pigment and heat-seal the fluororesin tube 3. A plurality of near-infrared lamps 1 are arranged parallel to the longitudinal direction of the roller,
The entire surface of the fluororesin tube 3 can be irradiated with infrared rays. In addition, as a heating furnace for irradiating such infrared rays, for example, a commercially available near-infrared image furnace (
(manufactured by Shinku Riko Co., Ltd.), etc. Heating is performed for several minutes by raising the temperature all at once to a temperature of about 350 to 400°C, at which the fluororesin melts. Note that it is desirable that the near-infrared rays be irradiated while the inside of the heating furnace is depressurized to below atmospheric pressure.

In this way, a small amount of air existing at the interface between the fluororesin tube 3 and the metal core @4 is removed, so that the adhesion is further improved.

(Function) In the method of the present invention, since the metal core shaft is previously subjected to high-temperature heat treatment in the atmosphere, oil and hydroxides adhering to the surface of the core shaft can be almost completely removed. This heat treatment forms an oxide film on the surface, creating a surface condition that has a strong affinity with the fluororesin tube.
The adhesion of the tube to the metal core shaft is greatly improved. Furthermore, since the heating method is based on infrared irradiation, the tube or metal core shaft absorbs infrared rays and is rapidly heated as a whole.
The tube is melted and firmly fused to the core shaft, and the heating time required for heat fusion of the tube is significantly shortened.

(Example) Examples of the present invention will be described.

Example 1 An aluminum core shaft with an outer diameter of 24 m and a body length of 270 mm was heated at a temperature of 300° C. in a constant temperature bath (manufactured by Karihashi Rika Kogyo Co., Ltd.) to form an oxide film on the surface. Next, this was covered with a PFA tube with an inner diameter of 24 mm and a thickness of 30 Bm, and placed in a near-infrared imaging furnace (manufactured by Shinku Riko Co., Ltd.), and a near-infrared lamp was energized to irradiate it with near-infrared rays to heat it at 360°C. The PFA tube was heat-sealed to the aluminum core shaft by heating at a high temperature for 5 minutes. The adhesive strength between the core shaft of the obtained PFA tube-covered roller and the PFA tube was measured and was 40.
It was strong at 0 g/■. Moreover, the tube surface was smooth.

Comparative Example 1 For comparison, a PFA tube-covered roller was manufactured in the same manner as the actual JLSI except that the aluminum core shaft was not heat-treated in advance. The adhesive strength between the core shaft of the obtained roller and the PFA tube was measured and found to be 225 g/■.

(Effects of the Invention) As described above, according to the method for manufacturing a fluororesin-coated roller of the present invention, a roller with strong adhesion between the core shaft and the fluororesin tube, excellent durability, fixing properties, etc. can be produced in a short time. It can be manufactured within

[Brief explanation of drawings]

The drawings are schematic cross-sectional views for explaining the method of manufacturing a fluororesin-coated roller of the present invention. 1...Near infrared lamp 2...Heating furnace 3...Fluororesin tube 4...Metal core shaft

Claims (1)

[Claims] (1) When coating a fluororesin tube on a metal core shaft and then heat-sealing it, the metal core shaft is a metal core shaft on which an oxide film has been previously formed on the surface by heating in the atmosphere, A method for producing a fluororesin-coated roller, which comprises coating the fluororesin tube thereon and then irradiating infrared rays from near the surface of the tube to heat and fuse the tube.