| abstract |
The present invention relates to a composite tubular article for use as the fixing belt in an image-forming device such as a copying machine etc., particularly as a fixing belt suited for thermal fixing, and also relates to a process for producing the same. n Conventionally known as an image-fixing belt is a belt consisting of a polyimide resin as the inner layer and a fluoroplastic as the outer layer. However, this fixing belt has problems that clear images cannot be obtained because the thickness of each layer is uneven, and that unglossed, so-called matt images cannot be obtained because the belt surface is smooth. n This invention provides a composite tubular article comprising a tubular inner layer made of a polyimide resin and a tubular outer layer made of a fluoroplastic, the outer circumferential surface of the fluoroplastic tubular outer layer having a surface roughness of 1 to 10 μm. The invention further provides, as a production process for the same, a process in which the outer layer is formed by use of a cylinder having an inner circumferential surface with a surface roughness of 1 to 10 μm, and a polyimide-resin tubular inner layer is formed on the inner circumferential surface of the outer layer by converting a poly(amic acid) into a polyimide, or a process in which an inner layer formed by converting a poly(amic acid) into a polyimide is immersed in or sprayed with a fluoroplastic solution in which a particulate material of 5 μm or smaller has been dispersed, thereby to form an outer layer. |