Wire manufacturing method wire manufacturing apparatus and wire

A method for manufacturing an electric wire comprising a conductive core and a cladding which is made of insulating synthetic resin and clads the core, the method comprising the step of:

• (1) moving straightly the core in a downstream direction;
• (2) cladding an outer periphery of said core with non-colored synthetic resin by extrusion cladding to form said cladding;
• (3) making a part of a rotatable rotor contact an outer surface of the cladding straightly moving and measuring intervals of the cladded core;
• (4) issuing a pulsating signal corresponding to an angle of rotation of the rotor from a measuring means to an exchanging means;
• and
• (5) coloring an outer surface of said cladding of non-colored synthetic resin with a coloring agent, the coloring agent being a liquid coloring material dissolved or dispersed in water or other solvent;
• wherein coloring portions are positioned along the downstream direction;
• the coloring portions color the outer surface of the cladding;
• said coloring step is executed immediately after said extrusion cladding step and before the synthetic resin constituting the cladding hardens, so that the coloring agent sinks into the cladding or bonds to the outer surface of the cladding;
• the outer surface of said cladding is colored with a plurality of colors by a plurality of coloring portions, each coloring portion being capable of applying a single color;
• a length of movement of the cladded core is measured with the measuring means;
• the measured length is determined to be equal to a distance between the coloring portions;
• and
• the color applied to the outer surface is changed when the measured length is equal to the distance so that the colors do not overlap each other on the outer surface of the cladding.

An apparatus for manufacturing an electric wire composed of a conductive core and a cladding which is made of insulating synthetic resin and clads the core, the apparatus comprising:

• an extrusion cladding unit for cladding an outer periphery of said core with non-colored synthetic resin by extrusion cladding to form said cladding;
• and;
• a coloring unit for coloring an outer surface of said cladding of non-colored synthetic resin with a coloring agent, the coloring agent being a liquid coloring material dissolved or dispersed in water or other solvent;
• wherein said coloring unit is arranged downstream of and immediately after said extrusion cladding unit in a direction of moving said core so as to be able to apply coloring agent before the synthetic resin has hardened;
• said coloring unit includes a plurality of coloring portions and an exchanging portion;
• the exchanging portion includes
• a measuring means for measuring an optional position of said electric wire in intervals that relate to the position of the coloring portions and having a rotatable rotor a part of which is in contact with the outer surface of the cladding straightly moving, and
• an exchanging means for selectively operating the coloring portions in relation to the intervals measured by said measuring means based on a distance between the coloring portions, a value of the distance being stored in the exchanging means, and
• the exchanging portion controls the selective operation of coloring portions;
• each coloring portion is capable of coloring the outer surface of the cladding in a single color;
• the coloring portions color the outer surface of the cladding immediately after the extrusion cladding so that the coloring agent sinks into the cladding or bonds to the outer surface of the cladding.