JP2021162718A - Manufacturing method of plastic optical fiber and manufacturing apparatus of plastic optical fiber - Google Patents

Abstract

To provide a manufacturing method of a plastic optical fiber suppressing a twist of a plastic optical fiber when passing through a measuring instrument.SOLUTION: A manufacturing method of a plastic optical fiber includes passing a plastic optical fiber through: an outer diameter and/or irregularity measuring instrument; and a twist prevention mechanism including a revolving roller having a V-shaped groove on a roll face arranged on an upstream side and a downstream side of the outer diameter and/or irregularity measuring instrument, so as to eliminate a twist of the plastic optical fiber.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a plastic optical fiber and an apparatus for manufacturing a plastic optical fiber.

As an optical transmitter, a plastic optical fiber (Plastic Optical Fiber: hereinafter may be referred to as POF) in which both the core and the cladding are made of plastic is attracting attention. In the POF manufacturing process, the outer diameter measuring instrument and / or the unevenness measuring instrument is used to detect the unevenness (variation of the outer diameter), foreign matter, and the like of the POF. However, if the POF is twisted when passing through the outer diameter measuring instrument and / or the unevenness measuring instrument, accurate detection may not be possible.

Japanese Unexamined Patent Publication No. 2001-048568

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a method for manufacturing a plastic optical fiber in which twisting of the plastic optical fiber when passing through a measuring instrument is suppressed. ..

In the method for manufacturing a plastic optical fiber according to the embodiment of the present invention, the plastic optical fiber is arranged in an outer diameter and / or unevenness measuring instrument, and upstream and downstream of the outer diameter and / or unevenness measuring instrument, in a V shape. It includes passing through an anti-twist mechanism including a rotating roll having a groove on the roll surface to untwist the plastic optical fiber.
In one embodiment, when the total holding angle of the rotating rolls included in the twist prevention mechanism is x (°) and the tension applied to the plastic optical fiber is y (g), the absolute values of each are as follows. Satisfy equations (1) and (2):
40 ≦ x ≦ 400 ・ ・ ・ (1)
−0.15x + 60 ≦ y ≦ −0.15x + 95 ... (2).
In one embodiment, the diameter of the plastic optical fiber is 300 μm or more.
According to another aspect of the present invention, a plastic optical fiber manufacturing apparatus is provided. The manufacturing apparatus includes a transport mechanism for transporting a plastic optical fiber while applying a predetermined tension; an outer diameter and / or an unevenness measuring instrument for measuring the outer diameter and / or unevenness of the plastic optical fiber; the outer diameter and / or An anti-twist mechanism including a rotary roll having a V-shaped groove on the roll surface, which is arranged upstream and downstream of the unevenness measuring instrument; °), When the tension applied to the plastic optical fiber is y (g), the absolute values thereof are configured to satisfy the following equations (1) and (2):
40 ≦ x ≦ 400 ・ ・ ・ (1)
−0.15x + 60 ≦ y ≦ −0.15x + 95 ... (2).

According to an embodiment of the present invention, in a method for manufacturing a plastic optical fiber, a rotating roll having a V-shaped groove on a roll surface in which the plastic optical fiber is arranged upstream and downstream of an outer diameter and / or unevenness measuring instrument. By passing through the twist prevention mechanism including the above, it is possible to suppress the twist of the plastic optical fiber when passing through the measuring instrument. As a result, unevenness (variation in outer diameter) of the plastic optical fiber, foreign matter, and the like can be accurately detected.

It is a schematic block diagram explaining the manufacturing method and manufacturing apparatus of the plastic optical fiber by one Embodiment of this invention. Each of (a) to (c) is a schematic side view showing a specific shape of a roll included in the twist prevention mechanism. It is the schematic explaining the typical deformation example of the transport path in a twist prevention mechanism. It is the schematic explaining the measuring method of the tension which eliminates a twist.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

A. Outline of Manufacturing Method of Plastic Optical Fiber In the manufacturing method of plastic optical fiber according to the embodiment of the present invention, a plastic optical fiber (POF) is used as an outer diameter and / or unevenness measuring instrument, and the outer diameter and / or unevenness measuring instrument. To eliminate the twist of the POF by passing it through an anti-twist mechanism including a rotating roll having a V-shaped groove on the roll surface, which is arranged upstream and downstream of the POF (hereinafter, may be referred to as an untwist process). include. FIG. 1 is a schematic configuration diagram illustrating a method for manufacturing a POF and a manufacturing apparatus according to one embodiment of the present invention. More specifically, with reference to FIG. 1, the above-mentioned manufacturing method is to prepare a preform by the preform manufacturing apparatus 1; to stretch the preform to prepare POF2; / Or pass through the unevenness measuring instrument 4 and the twist prevention mechanisms 31 and 32 arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument 4 to eliminate the twist of the POF; the POF 2 is wound up and rolled 7 Wind up with; The POF2 is conveyed by the take-up roll 5. Further, the POF 2 can be conveyed in a state where a predetermined tension is applied by a tension applying mechanism (for example, a load applying mechanism such as a dancer mechanism) 6. In the illustrated example, the transport path of POF2 changes the direction, but the transport path may be a straight line or may change the direction at a plurality of locations. Hereinafter, each step in the manufacturing method will be described together with the configuration of the corresponding device.

B. Formation of Preform The POF that can be used in the production method according to the embodiment of the present invention can be produced, for example, by preparing a preform in advance and stretching the preform. As used herein, a "preform" is an unstretched POF that typically has a core portion, a clad portion, and an overclad portion. The preform can be produced by the preform production device 1. The preform can be made by any suitable method. That is, the preform manufacturing apparatus 1 may have an arbitrary appropriate configuration depending on the method for producing the preform. Typical examples of the method for producing a preform include a melt extrusion method, a melt spinning method, a melt extrusion dopant diffusion method, and a rod-in-tube method. In these methods, industry-renowned procedures may be employed. For example, according to the melt extrusion method, the material constituting the core portion, the material constituting the clad portion, and the material constituting the overclad portion are each supplied to a concentric three-layer mold, and melt extrusion is performed at a predetermined temperature. By doing so, a preform can be produced. Further, for example, according to another melt extrusion method, the material constituting the core portion and the material constituting the clad portion are each supplied to a concentric two-layer mold, melt extrusion is performed at a predetermined temperature, and further, the melt extrusion is performed. A preform can be produced by using another two-layer mold to join the materials constituting the separately extruded overclad portion to the outside of the flow path of the melt in the core portion and the clad portion. In the melt spinning method, a spinning nozzle (typically, a three-layer nozzle) may be used instead of the mold.

C. Stretching the preform Then the preform is stretched. The stretching temperature of the preform can be appropriately set depending on the constituent materials of the core portion, the clad portion and the overclad portion. The stretching temperature is, for example, 150 ° C. to 310 ° C., preferably 200 ° C. to 260 ° C. The draw ratio is 10 to 600 times in one embodiment, 100 to 600 times in another embodiment, 10 to 300 times in yet another embodiment, and yet another. In the embodiment, it is 100 to 300 times. The stretching speed is preferably 1 m / min to 120 m / min, more preferably 10 m / min to 120 m / min, and even more preferably 10 m / min to 90 m / min.

As described above, POF2 can be produced. In the embodiment of the present invention, the POF (that is, after the stretching is completed) may be subjected to the untwisting treatment described later; the preform is subjected to the untwisting treatment while being stretched, and a predetermined stretching is performed at the time of final winding. May be completed. Therefore, in the present specification, "passing the POF through the anti-twist mechanism" includes both of the above two modes. In the illustrated example, for convenience, the fiber coming out of the preform manufacturing apparatus 1 is drawn as POF2.

D. Outer diameter and / or unevenness measurement The POF2 can pass through the outer diameter and / or unevenness measuring instrument 4 and detect its unevenness (variation in outer diameter), foreign matter, and the like. Since unevenness (variation in outer diameter) of POF, foreign matter and the like adversely affect the light transmission characteristics, it is preferable that the unevenness is as small as possible, the foreign matter is as small as possible, and the number of foreign matter is as small as possible. By passing POF2 through the outer diameter and / or unevenness measuring instrument 4, such unevenness (variation in outer diameter), foreign matter, and the like can be detected. Further, in the embodiment of the present invention, the twisting of the POF when passing through the outer diameter and / or the unevenness measuring instrument 4 is suppressed by the untwisting treatment described later, so that the unevenness (outer diameter) is suppressed in the POF manufacturing process. (Fluctuation), foreign matter, etc. can be detected accurately. In one embodiment, the outer diameter and / or unevenness measuring instrument 4 is an unevenness sensor. It is possible to detect unevenness and foreign matter more accurately by directly detecting the unevenness than by detecting the unevenness from the fluctuation of the outer diameter. The unevenness sensor has, for example, three unevenness detection units arranged in a plane orthogonal to the transport direction of the POF (typically, arranged at equal intervals on the circumference centered on the transport direction). As one set (one unevenness sensor), a plurality of sets (for example, two sets and three sets) can be arranged along the transport direction. With such a configuration, it is possible to reduce the detection omission of unevenness and foreign matter. More details are as follows. As described above, one concavo-convex sensor is configured with three concavo-convex detection units as one set, and each of the three concavo-convex detection units is derived from, for example, two outer diameter measurement sensors arranged along the transport direction of the POF. It is configured. That is, there are six outer diameter measurement sensors in one unevenness sensor. Assuming that these measured values are (D11, D12), (D21, D22), (D31, D32), the absolute value of the difference between the measured values of the respective outer diameter measurement sensors | D11-D12 |, | D21-D22 | Alternatively, it is configured to issue an alarm when any of | D31-D32 | exceeds a predetermined threshold value. Further, as described above, a plurality of unevenness sensors may be arranged along the transport direction in order to eliminate the blind spot for detection in the peripheral direction of the POF. When there are three unevenness detection parts (that is, three light emitting parts and three light receiving parts) in one unevenness sensor, they are arranged at intervals of 60 degrees on the circumference centered on the transport direction of the POF. Therefore, for example, when two unevenness sensors are arranged along the transport direction, each unevenness sensor is arranged at a position shifted by 30 degrees on the circumference. Similarly, for example, when three unevenness sensors are arranged along the transport direction, each unevenness sensor is arranged at a position shifted by 20 degrees on the circumference. For example, if the design diameter of the POF is 470 μm, the threshold can be, for example, 20 μm.

The outer diameter and / or unevenness measuring instrument 4 can be placed at any suitable position in the POF manufacturing process. The outer diameter and / or unevenness measuring instrument 4 may be arranged upstream of the take-up roll 5 as shown in the illustrated example, or may be arranged downstream of the take-up roll 5.

E. Untwisting process In the embodiment of the present invention, the POF2 is untwisted by the twist prevention mechanisms 31 and 32 arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument 4. 2 (a) to 2 (c) are schematic side views showing a specific shape of the rotary roll included in the twist prevention mechanism, respectively. The twist prevention mechanisms 31 and 32 each include a rotary roll 40. The rotary roll 40 typically has a roll body having a V-shaped groove 42 on the roll surface and a rotary shaft 41. As shown in FIGS. 2A to 2C, the V-shaped groove may have a substantially V-shaped cross section. That is, the V-shaped groove may have a V-shape as shown in FIG. 2 (a), and has a shape including an R-shape in which the apex of the V-shape is chamfered as shown in FIG. 2 (b). Also, as shown in FIG. 2C, the V-shaped apex may be a substantially trapezoidal shape with a flat apex, or the cross section may be a shape (not shown) similar to a U-shape. The depth D of the V-shaped groove can be appropriately set according to the total desired holding angle, the number of rotating rolls, the diameter R of the rotating rolls, the width W of the V-shaped groove, the tension applied to the POF, and the like. The width W of the V-shaped groove can also be appropriately set according to the total desired holding angle, the number of rotating rolls, the diameter R of the rotating rolls, the depth D of the V-shaped groove, the tension applied to the POF, and the like. The diameter R of the rotating rolls can also be appropriately set according to the total desired holding angles, the number of rotating rolls, the depth D and width W of the V-shaped groove, the tension applied to the POF, and the like. The depth D of the V-shaped groove is, for example, 2 mm to 10 mm, the width W of the V-shaped groove is, for example, 5 mm to 15 mm, and the diameter R of the rotating roll is, for example, 20 mm to 80 mm. The number of rotating rolls included in the anti-twist mechanism can be appropriately set according to the total desired holding angles. In the illustrated example, three rotating rolls are shown, but the number of rotating rolls may be two, and may be four or more (for example, 4 to 10, preferably 4 to 6). You may.

By passing the POF2 through the twist prevention mechanisms 31 and 32 as described above arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument 4 and subjecting it to the twist elimination treatment, the outer diameter and / or unevenness measuring instrument It is possible to suppress the twist of the POF2 when passing through. As a result, unevenness (variation in outer diameter) of POF, foreign matter, and the like can be accurately detected. Specifically: When an appropriate load (tension) is applied to the POF passing through the rotating roll having the V-shaped groove, the POF is pressed against the V-shaped groove of the rotating roll. As a result, the dynamic friction force (rolling resistance) between the POF and the rotating roll is increased, and the twisting of the POF can be suppressed. This action is more remarkable as the contact angle (area) between the POF and the rotating roll and the load (tension) applied to the POF are larger.

The arrangement positions of the twist prevention mechanisms 31 and 32 are not particularly limited as long as they are arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument 4, respectively. For example, the twist prevention mechanism 32 arranged downstream of the outer diameter and / or unevenness measuring instrument 4 may be arranged between the take-up roll 5 and the tension applying mechanism 6 as shown in the illustrated example, and the outer diameter and / or the outer diameter and / or the twist prevention mechanism 32 may be arranged between the take-up roll 5 and the tension applying mechanism 6. Alternatively, it may be arranged between the unevenness measuring instrument 4 and the take-up roll 5. When the outer diameter and / or unevenness measuring instrument 4 is arranged downstream of the take-up roll 5 (not shown), the twist prevention mechanism 31 may be arranged upstream of the take-up roll 5 with the take-up roll 5. It may be arranged between the outer diameter and / or the unevenness measuring instrument 4. In one embodiment, the twist prevention mechanism 31, the outer diameter and / or unevenness measuring instrument 4, and the twist prevention mechanism 32 may be arranged in order between the take-up roll 5 and the tension applying mechanism 6. With such a configuration, the tension applied to the POF can be precisely and intentionally adjusted.

In one embodiment, the anti-twist mechanisms 31 and 32 may be arranged in the same plane (on a straight transport path) including the transport path. With such a configuration, the possibility of twisting is significantly reduced as compared with the configuration in which the transport path is arranged before and after changing the direction. In another embodiment, the anti-twist mechanisms 31 and 32 may be arranged before and after the transport path changes direction as shown in the illustrated example. With such a configuration, the effect of the untwisting process can be realized even if there are restrictions on the facility where the POF manufacturing apparatus is provided.

The anti-twist mechanisms 31 and 32 may be arranged at intervals of preferably within 1000 mm, more preferably within 500 mm. With such a configuration, twisting of the POF when passing through the outer diameter and / or unevenness measuring instrument 4 can be suppressed more satisfactorily.

In one embodiment, when the total holding angle of the rotating roll 40 included in each of the twist prevention mechanisms 31 and 32 is x (°) and the tension applied to POF2 is y (g), the absolute value of each is The following equations (1) and (2) are satisfied:
40 ≦ x ≦ 400 ・ ・ ・ (1)
−0.15x + 60 ≦ y ≦ −0.15x + 95 ... (2).
With such a configuration, when passing through the outer diameter and / or unevenness measuring instrument, taking into consideration the tension during POF transport according to the purpose and the restrictions on the facility where the POF manufacturing device is provided. The twist of the POF can be satisfactorily suppressed. More details are as follows. If twisting is simply suppressed, a certain effect can be obtained by increasing the total holding angle of the rotating rolls in the twist prevention mechanism. However, if the total holding angle is increased, the mechanism of the POF manufacturing apparatus becomes extremely complicated, and the cost increases remarkably. Further, since the POF transport route is also complicated, the burden on the operator is significantly increased. On the other hand, if the total holding angle is too small, the suppression of twisting may be insufficient when the POF is conveyed with a practical tension. The total hugging angle is preferably 50 ° to 400 °, more preferably 100 ° to 400 °, even more preferably 150 ° to 350 °, and particularly preferably 200 ° to 300 °. When the total holding angle is within such a range, the twist of the POF when passing through the outer diameter and / or unevenness measuring instrument is satisfactorily suppressed with a practically appropriate transport tension while reducing the equipment load. be able to. Practical tension can be, for example, 30g-80g. If the tension is too small, the transfer may become unstable, and winding slack may occur during winding. If the tension is too high, winding tightening may occur during winding. If the twist is simply suppressed, a certain effect can be obtained by increasing the tension. However, according to the present embodiment, the outer diameter and / or the unevenness measuring instrument is passed while avoiding such a problem. The twisting of the POF can be satisfactorily suppressed. The hugging angle is a straight line connecting the center point of the rotary roll and the contact start point between the POF and the rotary roll when the rotary roll is viewed from a cross section perpendicular to the axial direction, and the center point of the rotary roll. It is an angle formed by a straight line connecting the POF and the contact end point of the rotary roll.

As the configuration of the transport path in the twist prevention mechanism, any suitable configuration may be adopted in which the total holding angle of the rotating rolls can be within the above-mentioned suitable range. FIG. 3 is a schematic view illustrating a typical modification of the transport path in the twist prevention mechanism. In any of the configurations shown in FIG. 3, if the total holding angle of the rotating rolls is within the above-mentioned suitable range, the rotating roll passes through the outer diameter and / or the unevenness measuring instrument with a practically appropriate transport tension. The twisting of the POF can be satisfactorily suppressed. Needless to say, even if the configuration is other than the illustrated example, if the total holding angle of the rotating rolls is within the above-mentioned suitable range, the rotating roll passes through the outer diameter and / or the unevenness measuring instrument with a practically appropriate transport tension. The twisting of the POF can be satisfactorily suppressed. The preferred configuration in the illustrated example is (3), (5) or (9). With such a configuration, there is an advantage that the POF can be conveyed linearly (the traveling direction of the POF does not change). Another preferred configuration in the illustrated example is (4), (7) or (8). With such a configuration, even if there are restrictions on the facility where the POF manufacturing apparatus is provided, the untwisting process can be appropriately performed.

The twist prevention mechanisms 31 and 32 may each have the same configuration (typically, the number of rotating rolls, the total holding angle, the transport path), or may have different configurations from each other.

The diameter of POF2 is preferably 300 μm or more, more preferably 400 μm to 1000 μm. In POF having such a diameter, the effect of the embodiment of the present invention is remarkable. For example, in a POF with a diameter of 250 μm, the twist of the POF as it passes through the outer diameter and / or unevenness measuring instrument with a practically appropriate transport tension, regardless of the total holding angle of the rotating rolls in the anti-twist mechanism. Can be suppressed.

In the present specification, the untwisting process has been described as a process in a continuous process from the production of the preform, but it is obvious to those skilled in the art that the untwisting process can be applied to any aspect of the POF manufacturing process. For example, the untwisting process may be applied during pre-shipment and / or post-shipment inspection of the POF and / or at the time of rewinding the POF.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

<Manufacturing example 1>
The purified trichloroethyl methacrylate (TCEMA) and diphenyl sulfide (DPS) as a dopant were mixed in a weight ratio of TCEMA: DPS = 100: 4. Further, dit-butyl peroxide was added as a polymerization initiator and n-lauryl mercaptan was added as a chain transfer agent so that the concentrations in the total weight were 0.03% by weight and 0.2% by weight, respectively. Then, filtration was performed with a membrane filter having a pore size of 0.2 μm. This mixed solution was degassed under reduced pressure while applying ultrasonic waves, and then placed in a polymerization vessel, and the monomer was polymerized over 40 hours while maintaining the temperature of the polymerization vessel at 120 ° C. to obtain a core rod.
On the other hand, purified TCEMA and MMA were mixed in a weight ratio of TCEMA: MMA = 20:80. Further, benzoyl peroxide as a polymerization initiator and n-butyl mercaptan as a chain transfer agent were added so that the concentrations in the total weight were 0.5% by weight and 0.3% by weight, respectively. Then, filtration was performed with a membrane filter having a pore size of 0.2 μm. This mixed solution was degassed under reduced pressure while applying ultrasonic waves, and then placed in a polymerization vessel, and the monomer was polymerized over 40 hours while maintaining the temperature of the polymerization vessel at 120 ° C. to obtain a clad portion rod.
The obtained core portion rod and clad portion rod are formed into a laminated multi-layer shape of the core portion and the clad portion by using a separate extrusion molding machine and a two-layer mold connected to them, and further heated flow. By passing it through the path for a certain period of time, the dopant contained in the core portion was diffused into the clad portion. Further, an overclad material XYLEX X7300CL [product name, manufactured by SABIC Innovative Plastics, polyester-modified polycarbonate] (hereinafter, may be simply referred to as PC) is melted by another extrusion molding machine, and a two-layer mold is used. An overclad portion was formed on the outermost periphery by merging with the flow path of the core portion and the clad portion melt described above. The molten resin discharged from the mold was taken up to obtain an unstretched GI type POF (preform).

<Example 1>
Using the apparatus shown in FIG. 1, the preform obtained in Production Example 1 was stretched and untwisted to finally obtain a POF having a diameter of 490 μm. As the rotary roll in the untwisting mechanism, one having a groove having a V-shaped cross section as shown in FIG. 2A was used. When the upstream and downstream twist relieving mechanisms were configured as shown in FIGS. 3 (1) to (11), the tension at which the twist was relieved was investigated. The results are shown in Table 1.
The tension was measured as follows. As shown in FIG. 4, a tape that serves as a twist mark is attached to the POF, a weight is attached to one POF (left side in the illustrated example), and the other POF (right side in the illustrated example) is viewed from the long direction of the POF. The tape was twisted so as to rotate 360 °, and it was observed whether or not the POF (mark tape) on the left side rotated at that time. By changing the weight of the weight to be attached, the minimum weight at which the left POF (mark tape) does not rotate is defined as the "tension that eliminates twisting". The POF to which the weight is attached is a POF that faces downward. For example, in the configuration shown in (3) of FIG. 3, the POF is rotated by 90 ° and measured so that one POF faces downward. ..

<Reference example 1>
The tension at which the twist was eliminated was examined in the same manner as in Example 1 except that a POF having a final diameter of 250 μm was prepared from the preform obtained in Production Example 1. The results are shown in Table 1.

As is clear from Table 1, according to the embodiment of the present invention, the twisting of the POF when passing through the outer diameter and / or unevenness measuring instrument can be satisfactorily suppressed with a practically appropriate transport tension. Further, as is clear from Reference Example 1, it can be seen that such an effect is an effect peculiar to a POF having a diameter of a predetermined value or more.

The plastic optical fiber obtained by the manufacturing method of the present invention is useful as a component of an optical fiber cable intended for high-speed communication. Furthermore, by changing the shape, optical elements such as optical waveguides, lenses for steel cameras, video cameras, telescopes, eyeglasses, plastic contact lenses, sunlight condensing, etc., concave mirrors, polygons, etc. It can be applied as an optical member of mirrors such as, and prisms such as pentaprisms.

1 Preform making equipment 2 Plastic optical fiber (POF)
4 Outer diameter and / or unevenness measuring instrument 5 Take-up roll 6 Tension application mechanism 7 Take-up roll 31 Twist prevention mechanism 32 Twist prevention mechanism

Claims (4)

An anti-twist mechanism comprising a plastic optical fiber with an outer diameter and / or unevenness measuring instrument and a rotating roll having a V-shaped groove on the roll surface, which is arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument. To untwist the plastic optical fiber, including
Manufacturing method of plastic optical fiber. When the total holding angle of the rotating rolls included in the twist prevention mechanism is x (°) and the tension applied to the plastic optical fiber is y (g), their absolute values are the following equations (1) and (2). ) Satisfying the method for manufacturing a plastic optical fiber according to claim 1.
40 ≦ x ≦ 400 ・ ・ ・ (1)
−0.15x + 60 ≦ y ≦ −0.15x + 95 ... (2). The method for producing a plastic optical fiber according to claim 1 or 2, wherein the diameter of the plastic optical fiber is 300 μm or more. With a transport mechanism that transports plastic optical fibers while applying a predetermined tension;
With an outer diameter and / or unevenness measuring instrument that measures the outer diameter and / or unevenness of a plastic optical fiber;
With an anti-twist mechanism including a rotating roll having a V-shaped groove on the roll surface, arranged upstream and downstream of the outer diameter and / or unevenness measuring instrument;
With
When the total holding angle of the rotating rolls included in the twist prevention mechanism is x (°) and the tension applied to the plastic optical fiber is y (g), the absolute values of the respective absolute values are the following equations (1) and (2). ) Is configured to satisfy the plastic optical fiber manufacturing equipment:
40 ≦ x ≦ 400 ・ ・ ・ (1)
−0.15x + 60 ≦ y ≦ −0.15x + 95 ... (2).

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