METHOD FOR COATING ULTRAVIOLET-CURABLE RESIN ON LINEAR BODY

摘要

PROBLEM TO BE SOLVED: To prevent a clouding from occurring on an ultraviolet-curing cylindrical body consisting of a quartz tube or the like and thereby decrease the replacement frequency of the cylindrical body by coating titanium dioxide on the inner face of an ultraviolet-transmitting cylindrical body through which a linear body coated with an ultraviolet-curable resin passes. SOLUTION: Ultravilet rays emitted from an ultraviolet rays bulb 4 are made to reflect by a reflector 3 to be emitted to an ultraviolet-curing cylindrical body 2 in a curing device 1, so that an ultraviolet-curable resin applied to an optical fiber 10 passing through the interior of the cylindrical body 2, is cured. In this case, an inert gas is purged through the ultraviolet-curing cylindrical body 2 by regulating the flow rate with the help of a flow rate regulator 8 to create a mixed gas atmosphere of air and the inert gas. Further a shutter 7 is arranged at the inlet 5 and the outlet 6 of the curing device 1 to regulate the internal oxygen concentration of the ultraviolet- curing cylindrical body 2. Besides a titanium dioxide is applied to the inner face of the cylindrical body 2 and at the same time, the oxygen concentration in the cylindrical body 2 is set at 0.1 or more and below the oxygen concentration of an atmosphere and then ultraviolet rays are emitted.