Abstract: A support for photographic paper is produced by a method including the steps of coating one or two surfaces of a substrate sheet with a resinous melt includes a water-proof thermoplastic polymer and a pigment, by a melt-extrude-coating method, and solidifying the coating layer of the resinous melt on the substrate sheet, and wherein at least one melt-kneading procedure is applied to the resinous melt in a melt extruder having a pair of biaxial screws engaged with each other and satisfying the relationship (i)L.gtoreq.20D (I)wherein L is a length of the screws and D is a diameter of the screws, and provided with at least one pair of kneading disks located in at least a portion of the screws.

Abstract: A spark plug having a porcelain insulator affixed with a bushing of a rubber, an oil-impregnated rubber or a thermosetting elastomer such as a silicone resin. The spark plug is connected to an ignition system by a spark plug connecting structure including a plug terminal attached to the extremity of a high-tension resistance cord so as to seize the electrode of the spark plug, and a plug cap covering the free end portion of the high-tension resistance cord and, the plug terminal. In connecting the spark plug to the ignition system, the plug cap is fitted tightly over the bushing so that the porcelain insulator and the electrode of the spark plug, and the plug terminal are sealed perfectly.