COMPOSITE TUBULAR ARTICLE AND ITS PRODUCTION METHOD

摘要

This invention relates to a composite tubular article used as a belt which is suitable for fixation on an image forming apparatus such as a duplicating machine, particularly for heat fixation, and to its production method. Conventionally, a belt having a polyimide resin on the inner layer and a fluororesin on the outer layer is known as an image fixing belt but this belt involves the problems that a clear and vivid image cannot be obtained because the thickness of each layer is not uniform and a lusterless or so-called "mat" image cannot be obtained due to a smooth belt surface. To solve the problems with the prior art technique described above, the present invention provides a composite tubular article consisting of a tubular inner layer made of a polyimide resin and a tubular outer layer made of a fluororesin, whereby surface coarseness of the outer peripheral surface of the fluororesin tubular outer layer is from 1 to 10 mu m. As the production method of this article, the present invention provides a method which comprises forming the outer layer by use of a cylinder having an inner peripheral surface having surface coarseness of 1 to 10 mu m and forming the polyimide resin tubular inner layer on its inner peripheral surface by imidation of a polyamidic acid, or a method which comprises dipping the inner layer formed by the imidation of the polyamidic acid in a fluororesin solution in which particles having a particle diameter of up to 5 mu m are dispersed or spraying the solution to the inner layer to form the outer layer.