JP2003043318A - Method for manufacturing optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber by which a coloring defect of a primary coating is substantially eliminated. SOLUTION: The method is characterized by the fact that, when an optical fiber F2 is manufactured by feeding a blanc fiber F1, which is wound on a feeding bobbin 3, coloring the outer periphery of the blanc fiber F1 with a coloring die 7 and taking up to a take-up bobbin 13, variations in the feeding tension of the blanc fiber F1 is controlled to be within ±10 gf, with a tension control dancer 5 being provided between the feeding bobbin 3 and the coloring die 7.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical fiber for manufacturing an optical fiber having a good surface property. 2. Description of the Related Art Conventionally, a bare fiber is obtained by heating a preform to a high temperature and drawing it softly. The drawn bare fiber is subjected to primary coating (coloring), and then the primary coated optical fiber is wound on a winding bobbin. In the above-mentioned coloring process, as a cause of the defect at the time of manufacturing, there was an excessive fluctuation of the feeding tension. The above-mentioned excessive fluctuation of the feeding tension in the prior art is a fluctuation in the tension caused by the surface tack, and in order to reduce defective coloring, an optical fiber having a small fluctuation in the tension is required. You need to use
The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a method for manufacturing an optical fiber in which primary coating (coloring processing) has almost no defective coloring. According to a first aspect of the present invention, there is provided a method for producing a colored optical fiber, wherein the bare fiber wound around a delivery bobbin is fed out and the bare fiber is fed by a colored die. When producing an optical fiber by coloring the outer periphery of the fiber and winding it on a take-up bobbin, a fluctuation width of the sending tension of the bare fiber by a tension control dancer provided between the sending bobbin and the coloring die. Is controlled within ± 10 gf. Therefore, the tension control dancer provided between the delivery bobbin and the coloring die controls the variation of the delivery tension of the primary-coated (colored) fiber within ± 10 gf, thereby controlling the primary coating. Almost no defective coloring. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an optical fiber manufacturing apparatus 1. In FIG. 1, the delivery bobbin 3 is placed in a heating furnace made of a preform such as carbon or zirconia (zirconium oxide) and heated to a temperature of, for example, about 2000 to 2100 ° C., and is drawn softly to a required fiber diameter at a stretch. After that, a bare fiber F1 having a diameter of 125 μm is wound up. The bare fiber F1 wound on the delivery bobbin 3 is delivered by rotating the delivery bobbin 3. This sent bare fiber F
In 1, the tension is controlled by a tension control dancer 5 of three horizontal sets. The bare fiber F1 that has passed through the tension control dancer 5 is colored on the outer periphery by a coloring die 7, and then is wound on a winding bobbin 13 as an optical fiber F2 through a UV lamp 9 and an outer diameter measuring device 11. The tension of the optical fiber F2 measured by the tension control dancer 5 is taken into the control device 15 so that the tension falls within the range of the tension set in advance by the tension control dancer 5, and the tension is set in the control device 15 in advance. The speed (rotation) of the delivery bobbin 3 is controlled so that the measured tension of the optical fiber F2 falls within a range of ± 10 gf within a predetermined range of the tension by comparing and judging with the tension. is there. That is, using the optical fiber manufacturing apparatus 1 described above, the optical fiber F2 is used.
The fluctuation width of the feeding tension was monitored, and the correlation with the coloring failure frequency was clarified. Table 1 below shows the relationship between the variation in the feeding tension and the frequency of occurrence of defects when the optical fiber F2 of 100 km is colored. In addition, the fluctuation of the feeding tension shown in Table 1 is within 10 gf,
Fluctuations in the actually measured feeding tension in the case of 20 gf or less are shown in FIGS. 2 and 3, for example. [Table 1] As a result, as shown in Table 1, when the variation of the actually measured feeding tension is ± 15 to ± 20 gf,
The number of occurrences of coloring failure was 1 to 3 pieces, whereas the number of occurrences of coloring failure was 0 when the actually measured variation in the feeding tension was ± 5 to ± 10 gf. From this fact, it was found that if the actual fluctuation of the feeding tension was controlled within ± 10 gf, the number of occurrences of coloring failure was almost eliminated. Therefore, the optical fiber manufacturing apparatus 1
When the optical fiber strand F2 is manufactured by using the optical fiber strand F2 measured by the tension control dancer 5, the tension when the optical fiber strand F2 is wound around the winding bobbin 13 falls within a preset tension range. The tension is taken into the control device 17 and is compared with the tension set in advance by the control device 15, and the measured tension of the optical fiber F <b> 2 is within the range of the preset tension variation ± 10 gf. By controlling the speed of the delivery bobbin 3, it is possible to obtain an optical fiber F2 free from occurrence of coloring failure. In addition,
The present invention is not limited to the above-described embodiment,
The present invention can be implemented in other modes by making appropriate changes. As will be understood from the above description of the embodiments of the invention, according to the first aspect of the present invention, the nakedness is controlled by the tension control dancer provided between the delivery bobbin and the coloring die. By controlling the fluctuation width of the fiber sending tension to within ± 10 gf, it is possible to almost eliminate the coloring failure of the primary coating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view of an optical fiber manufacturing apparatus embodying the present invention. FIG. 2 is a chart showing a relationship between a feeding length and a tension fluctuation width when the tension fluctuation width is within ± 10 gf. FIG. 3 is a chart showing a relationship between a feeding length and a tension fluctuation width when the tension fluctuation width is within ± 20 gf. [Description of Signs] 1 Optical fiber raw wire manufacturing device 3 Sending-out bobbin 5 Tension control dancer 7 Coloring die 9 UV lamp 11 Outer diameter measuring device 13 Winding bobbin 15 Controller F1 Bare fiber F2 Optical fiber wire

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Claims (1)

Claims: 1. A bare fiber wound on a delivery bobbin is sent out, colored around the bare fiber by a coloring die, wound around a winding bobbin, and an optical fiber is manufactured. In this case, a method for producing an optical fiber is characterized in that a tension control dancer provided between the delivery bobbin and the coloring die controls a variation width of the delivery tension of the bare fiber to within ± 10 gf.