Abstract: A method of manufacturing and mass-producing a seamless heat-resistant resinous tube with a uniform tube wall thickness and circumference, which includes the steps of coating the precursor solution of a tube material to the surface of a core at a thickness greater than the tube wall thickness; passing a metallic die having a wider inside diameter than the diameter of the core along the outside of the core by utilizing the resistant force of the precursor solution without restricting the metallic die or the core, thus forming a tube around the core; treating the tube around the core to give it strength as a tube; and separating the tube from the core.

Abstract: A heat-resistant fabric coated or impregnated with tetrafluoroethylene resin is baked at such a temperature for such a period of time that only the resin layer is baked without impairing the strength of the fabric substrate because the substrate is not subjected to a high temperature for a long time.

Abstract: An improved composite rubber material having a baked layer of fluorine resin of 10 microns to about 1 millimeter in thickness is proposed. The coated layer of fluorine resin is baked at a temperature over 400.degree. C. for not more than 7 minutes. This assures that the fluorine resin is baked without deteriorating the rubber material.

Abstract: A release agent applicator for a copying machine in which voids in the release agent contained in the applicator are substantially eliminated, thus providing an improved spreading performance of the release agent onto a fixing roll of the copying machine. The release agent applicator is made of a porous polyethylene tetrafluoride tube, the pores of which are partially closed except in areas where the release agent is to ooze out onto the fixing roll. Those partially closed pores in the tube are partially closed by a flattening operation so that they cannot draw release agent thereinto by capillary action.

Abstract: An electrochromic display device and apparatus for producing such a device including a display electrode, a confronting electrode, and an electrolyte-impregnated porous layer disposed between the electrodes. The porous member has an average pore diameter of 0.1 to 50 .mu.m with porous spaces occupying at least 30% by volume of the porous member. Pigment is held in the porous spaces to an extent of 1 to 50% by volume of the porous spaces. With this construction, the display device provides an excellent display background.