Optical fiber manufacturing apparatus and optical fiber manufacturing method

Abstract

The equipment configuration of the optical fiber manufacturing apparatus in the pass line from the capstan to the bobbin is simplified. [Solution] On the pass line from the capstan 17 that takes in the optical fiber G2 to the bobbin B located downstream of the capstan 17, only a guide roller 18 for guiding the optical fiber G2, a dancer roller unit 100 for applying tension to the optical fiber G2, and a tension measuring unit 19 for measuring the tension of the optical fiber G2 are provided. The guide roller 18 is rotatably mounted on a fixed shaft FS attached to a fixed wall FW. The dancer roller unit 100 has a dancer roller 110 for winding the optical fiber G2 and a tension adjustment mechanism 120 for adjusting the tension applied to the optical fiber G2 by the dancer roller 110. At least one of the bobbin motor that rotates the bobbin B or the tension adjustment mechanism 120 is driven and controlled by a tension control device 21 based on the tension applied to the optical fiber G2 as measured by the tension measuring unit 19, so that the tension applied to the optical fiber G2 becomes a predetermined tension.

Description

Technical Field

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[0001] The present invention relates to an optical fiber manufacturing apparatus and an optical fiber manufacturing method.

Background Art

[0002] Conventionally, as an optical fiber manufacturing apparatus for winding a resin-coated optical fiber wound around a bobbin by being drawn from a drawing furnace that heats and softens a glass base material, on a pass line from a capstan that draws the optical fiber to a bobbin provided downstream of the capstan, a screening device that applies a screening tension to the optical fiber in a screening process to measure the tension of the optical fiber, and a dancer roller device that adjusts the tension of the optical fiber are provided (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described optical fiber manufacturing apparatus, since two devices, a screening device and a dancer roller device, are provided on the pass line from the capstan to the bobbin, the optical fiber manufacturing apparatus has become complicated.

[0005] Therefore, the present invention solves the problems of the prior art as described above. That is, the object of the present invention is to simplify the device configuration of the optical fiber manufacturing apparatus in the pass line from the capstan to the bobbin.

Means for Solving the Problems

[0006] The optical fiber manufacturing apparatus of the present disclosure is an optical fiber manufacturing apparatus that winds a resin-coated optical fiber drawn from a drawing furnace that heats and softens a glass base material onto a bobbin, wherein only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided on a pass line from a capstan that takes in the optical fiber to the bobbin provided downstream of the capstan, the guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, the dancer roller unit has a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller, and at least one of the bobbin motor that rotates the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device based on the tension applied to the optical fiber measured by the tension measuring unit so that the tension applied to the optical fiber becomes a predetermined tension.

[0007] Furthermore, the optical fiber manufacturing method of the present disclosure is an optical fiber manufacturing apparatus that winds a resin-coated optical fiber drawn from a drawing furnace that heats and softens a glass base material onto a bobbin, wherein only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided on the pass line from the capstan that takes in the optical fiber to the bobbin located downstream of the capstan, the guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, and the dancer roller unit includes a dancer roller for winding the optical fiber, A method for manufacturing an optical fiber using an optical fiber manufacturing apparatus, the apparatus comprising: a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller, wherein at least one of the bobbin motor for rotating the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device so that the tension applied to the optical fiber becomes a predetermined tension, the apparatus comprising: a tension measurement step in which the tension measuring unit measures the tension applied to the optical fiber; and a tension adjustment step in which the tension control device drives and controls at least one of the bobbin motor or the tension adjustment mechanism based on the tension applied to the optical fiber measured by the tension measuring unit.

[0008] In this context, "screening test" refers to "an test to determine whether or not an optical fiber breaks when a certain tension is applied to it." [Effects of the Invention]

[0009] According to the above, the equipment configuration of the optical fiber manufacturing apparatus in the pass line from the capstan to the bobbin can be simplified. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an optical fiber manufacturing apparatus according to the first embodiment of this disclosure. [Figure 2] This is a side view showing an example of the installation state of the guide rollers shown in Figure 1. [Figure 3]Figure 1 is a side view showing an example of a dancer roller unit. [Figure 4] This is a schematic diagram of an optical fiber manufacturing apparatus according to a second embodiment of this disclosure. [Figure 5] Figure 4 is a side view showing an example of a dancer roller unit. [Modes for carrying out the invention]

[0011] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described. The optical fiber manufacturing apparatus of the present disclosure is an optical fiber manufacturing apparatus that winds a resin-coated optical fiber drawn from a drawing furnace that heats and softens a glass base material onto a bobbin, wherein only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided on a pass line from a capstan that takes in the optical fiber to the bobbin provided downstream of the capstan, the guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, the dancer roller unit has a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller, and at least one of the bobbin motor for rotating the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device based on the tension applied to the optical fiber measured by the tension measuring unit so that the tension applied to the optical fiber becomes a predetermined tension. Thus, on the pass line from the capstan that takes in the optical fiber to the bobbin located downstream of the capstan, only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided. The guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, and the dancer roller unit has a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller. As a result, the only roller unit with a drive source on the pass line from the capstan to the bobbin is the dancer roller unit, thus eliminating the need for conventionally provided rollers. This eliminates the need for motors to drive the cleaning roller and tension help roller, simplifying the equipment configuration of the optical fiber manufacturing apparatus in the pass line from the capstan to the bobbin. Furthermore, since at least one of the bobbin motor that rotates the bobbin or the tension adjustment mechanism is driven and controlled by the tension control device based on the tension applied to the optical fiber measured by the tension measuring unit, and the tension of the optical fiber is adjusted to a predetermined tension, the tension of the optical fiber can be adjusted to a predetermined tension simply by the tension control device driving and controlling at least one of the bobbin motor or the tension adjustment mechanism, allowing the tension applied to the optical fiber to be changed even during drawing.

[0012] In the optical fiber manufacturing apparatus described above, (2) a bobbin switcher is provided to switch the winding destination of the optical fiber drawn from the drawing furnace to either the bobbin that winds the optical fiber while performing a screening inspection or the bobbin that winds the optical fiber after the screening inspection is completed, and the tension control device sets the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber during the screening inspection. In this way, the tension control device sets the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber during the screening inspection. This allows the tension applied to the optical fiber to change without stopping the drawing of the optical fiber when the screening inspection is completed, thereby improving the manufacturing efficiency of the optical fiber.

[0013] In the optical fiber manufacturing apparatus described above, (3) the tension adjustment mechanism of the dancer roller unit is an air cylinder that applies vertical thrust to the dancer roller perpendicular to the axial direction of the rotation axis of the dancer roller. This allows the dancer roller to move in only one direction, vertically, and the installation layout of the tension adjustment mechanism to be space-saving, thus making it easy to miniaturize optical fiber manufacturing equipment.

[0014] In the optical fiber manufacturing apparatus described above, (4) the tension adjustment mechanism of the dancer roller unit includes a torque-applying motor having a drive shaft extending substantially parallel to the rotation axis of the dancer roller and an encoder for detecting the rotational position of the drive shaft, and an arm member having one end connected to the rotation axis of the dancer roller and the other end connected to the drive shaft of the torque-applying motor. As a result, when the torque-applying motor is rotated, torque is applied to the dancer roller via the arm member, making it easy to estimate the position of the dancer roller from the encoder of the torque-applying motor, and enabling low-cost position detection of the dancer roller.

[0015] The optical fiber manufacturing method of the present disclosure is an optical fiber manufacturing apparatus for winding a resin-coated optical fiber drawn from a drawing furnace that heats and softens a glass base material onto a bobbin, wherein only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided on a pass line from a capstan that takes in the optical fiber to the bobbin provided downstream of the capstan, the guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, and the dancer roller unit includes a dancer roller for winding the optical fiber, A method for manufacturing an optical fiber using an optical fiber manufacturing apparatus, the apparatus comprising: a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller, wherein at least one of the bobbin motor for rotating the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device so that the tension applied to the optical fiber becomes a predetermined tension, the apparatus comprising: a tension measurement step in which the tension measuring unit measures the tension applied to the optical fiber; and a tension adjustment step in which the tension control device drives and controls at least one of the bobbin motor or the tension adjustment mechanism based on the tension applied to the optical fiber measured by the tension measuring unit. Thus, on the pass line from the capstan that takes in the optical fiber to the bobbin located downstream of the capstan, only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided. The guide roller unit is rotatably mounted on a fixed shaft attached to a fixed wall, and the dancer roller unit has a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller. As a result, the only roller unit with a drive source on the pass line from the capstan to the bobbin is the dancer roller unit, The motors previously required to drive the screening roller and tension help roller are no longer needed, simplifying the configuration of the optical fiber manufacturing apparatus in the pass line from the capstan to the bobbin. Furthermore, because the system includes a tension adjustment step in which the tension control device drives at least one of the bobbin motor or tension adjustment mechanism based on the tension applied to the optical fiber measured by the tension measuring unit, the tension of the optical fiber can be adjusted to a predetermined tension simply by the tension control device driving at least one of the bobbin motor or tension adjustment mechanism, allowing the tension applied to the optical fiber to be changed even during drawing.

[0016] In the above-described method for manufacturing optical fibers, (6) the optical fiber manufacturing apparatus further comprises a bobbin switcher that switches the winding destination of the optical fiber drawn from the drawing furnace to either the bobbin that winds the optical fiber while performing a screening inspection or the bobbin that winds the optical fiber after the screening inspection is completed, and further comprises a bobbin switching step that switches the winding destination of the optical fiber from the bobbin that winds the optical fiber while performing a screening inspection to the bobbin that winds the optical fiber after the screening inspection is completed, and sets the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber while performing a screening inspection. By further including a bobbin switching step of switching from a bobbin for winding the optical fiber while screening the take-up destination of the optical fiber to a bobbin for winding the optical fiber after the screening inspection is completed, and setting the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber while screening the inspection, when the screening inspection is completed, the tension applied to the optical fiber changes without stopping the drawing of the optical fiber, so that the manufacturing efficiency of the optical fiber can be improved.

[0017] [Details of Embodiments of the Present Disclosure] Hereinafter, specific examples of an optical fiber manufacturing apparatus and an optical fiber manufacturing method according to the present disclosure will be described.

[0018] <First Embodiment of Optical Fiber Manufacturing Apparatus> First, based on FIGS. 1 to 3, a first embodiment of an optical fiber manufacturing apparatus according to the present disclosure will be described. FIG. 1 is a schematic diagram of an optical fiber manufacturing apparatus according to the first embodiment of the present disclosure, FIG. 2 is a side view showing an example of the installation state of the guide rollers shown in FIG. 1, and FIG. 3 is a side view showing an example of the dancer roller unit shown in FIG. 1.

[0019] As shown in FIG. 1, an optical fiber manufacturing apparatus (optical fiber manufacturing apparatus) 10 includes, at the most upstream position, a drawing furnace 11 that heats and softens a glass母材 G for an optical fiber.

[0020] This drawing furnace 11 has a cylindrical furnace core tube 11a into which the glass母材 G is supplied inside, a heating element 11b surrounding the furnace core tube 11a, and a gas supply unit 11c that supplies purge gas to the furnace core tube 11a. The upper part of the glass母材 G is gripped by a母材 feed unit F, and the glass母材 G is fed into the furnace core tube 11a using the母材 feed unit F. In the drawing furnace 11 configured in this way, when the lower end portion of the glass base material G is heated by the heating element 11b and drawn downward, a glass fiber G1, which will become the central portion of the optical fiber G2, is formed.

[0021] The optical fiber manufacturing apparatus 10 is equipped with a cooling unit 12 downstream of the drawing furnace 11. The glass fiber G1 drawn downward from the drawing furnace 11 is cooled by the cooling unit 12.

[0022] The cooling unit 12 is supplied with a cooling gas, such as helium gas. Furthermore, the cooling unit 12 may use a cooling method that utilizes a cooling gas other than helium gas, as long as it can cool the glass fiber G1 without contact.

[0023] The optical fiber manufacturing apparatus 10 is equipped with an outer diameter measuring unit 13 downstream of the cooling unit 12. The glass fiber G1, cooled by the cooling unit 12, has its outer diameter measured by the outer diameter measuring unit 13 and is then sent downward.

[0024] The outer diameter measuring unit 13 is configured to measure the outer diameter of the glass fiber G1 using, for example, laser light. The outer diameter measuring unit 13 may be configured using a method other than the laser method, as long as it can measure the outer diameter of the glass fiber G1 in a non-contact manner.

[0025] The optical fiber manufacturing apparatus 10 includes a coating unit 14 downstream of the outer diameter measuring unit 13. The glass fiber G1, whose outer diameter has been measured by the outer diameter measuring unit 13, is coated with, for example, a urethane acrylate resin, which is an ultraviolet-curing resin. When this urethane acrylate resin is irradiated with ultraviolet light and hardened, it becomes an optical fiber G2 with the glass fiber G1 coated with resin.

[0026] The optical fiber manufacturing apparatus 10 is equipped with a roller 15 directly below the coating unit 14 on the downstream side. After passing through the covering unit 14, the optical fiber G2 has its direction of travel changed by the roller 15 directly below it.

[0027] The direct-below roller 15 is positioned directly below the drawing furnace 11 and guides the optical fiber G2 as it is drawn out of the drawing furnace 11 and travels along the vertical direction. The roller 15 directly below is provided with grooves of a predetermined shape, such as a V-shaped fiber running groove in cross-section, and the optical fiber G2 is guided by contacting the inner wall surface of these grooves.

[0028] The optical fiber manufacturing apparatus 10 is equipped with a guide roller 16 downstream of the direct roller 15. After passing the roller 15 directly below, the optical fiber G2 has its direction of travel changed by the guide roller 16.

[0029] The guide roller 16 is also provided with grooves of a predetermined shape, such as a V-shaped fiber running groove in cross-section, and the optical fiber G2 is guided by contacting the inner wall surface of these grooves.

[0030] The optical fiber manufacturing apparatus 10 is equipped with a capstan 17 that takes in the optical fiber G2 after it has passed through the guide roller 16.

[0031] The optical fiber manufacturing apparatus 10 is equipped with a plurality (two in this embodiment) of guide rollers 18 downstream of the capstan 17. After passing through the capstan 17, the optical fiber G2 has its direction of travel changed by the guide roller 18.

[0032] As shown in Figure 2, the guide roller 18 is rotatably mounted on a fixed shaft FS attached to a fixed wall FW. This guide roller 18 is also provided with grooves of a predetermined shape, such as a V-shaped fiber running groove in cross-section, and the optical fiber G2 is guided by contacting the inner wall surface of these grooves.

[0033] The optical fiber manufacturing apparatus 10 is equipped with a dancer roller unit 100 downstream of the guide roller 18. The optical fiber G2, having passed through the guide roller 18, is subjected to tension by the dancer roller unit 100 and sent downstream.

[0034] As shown in Figure 3, the dancer roller unit 100 includes a dancer roller 110 for winding the optical fiber G2, and an air cylinder 120 which serves as a tension adjustment mechanism for adjusting the tension applied to the optical fiber G2 by the dancer roller 110.

[0035] The air cylinder 120 has a movable part 121 connected to the rotation axis 111 of the dancer roller 110, allowing the dancer roller 110 to move freely in the vertical direction (in a direction perpendicular to the axial direction of the rotation axis 111 of the dancer roller 110). In other words, the air cylinder 120 imparts vertical thrust to the dancer roller 110.

[0036] The optical fiber manufacturing apparatus 10 is equipped with a tension measuring unit 19 downstream of the dancer roller unit 100 for measuring the tension of the optical fiber G2. The tension of the optical fiber G2, which has passed through the dancer roller unit 100, is measured by the tension measuring unit 19.

[0037] The optical fiber manufacturing apparatus 10 is further equipped with a guide roller 18 downstream of the tension measuring unit 19. After passing through the tension measuring unit 19, the optical fiber G2 has its direction of travel changed by the guide roller 18.

[0038] The optical fiber manufacturing apparatus 10 is equipped with a bobbin changer 20 on the downstream side of the guide roller 18, to which a plurality (two in this embodiment) of bobbins B are attached. Therefore, the optical fiber G2, which has been drawn from the drawing furnace 11 and coated with resin, is wound onto the bobbin B.

[0039] The bobbin switcher 20 is a device that switches the winding destination of the optical fiber G2 between bobbin B (inspection bobbin Bt) which winds the optical fiber G2 while performing a screening inspection, and bobbin B (normal use bobbin Bn) which winds the optical fiber G2 after the screening inspection is completed. The device is equipped with bobbin motors (not shown) to rotate both the inspection bobbin Bt and the normal use bobbin Bn.

[0040] Furthermore, the optical fiber manufacturing apparatus 10 is electrically connected to the dancer roller unit 100, the tension measuring unit 19, and the bobbin changer 20, and includes a tension control device 21 that drives and controls the air cylinder 120 and the bobbin motor of the bobbin changer 20 based on the tension measurement results of the tension measuring unit 19.

[0041] With the optical fiber manufacturing apparatus 10 configured in this way, only a guide roller 18 for guiding the optical fiber G2, a dancer roller unit 100 for applying tension to the optical fiber G2, and a tension measuring unit 19 for measuring the tension of the optical fiber G2 are provided on the pass line from the capstan 17 that takes in the optical fiber G2 to the bobbin B located downstream of the capstan 17. The guide roller 18 is rotatably mounted on a fixed shaft FS attached to a fixed wall FW, and the dancer roller unit 100 has a dancer roller 110 for winding the optical fiber G2 and an air cylinder 120 which is a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller 110. As a result, the only roller unit with a drive source in the pass line from the capstan 17 to the bobbin B is the dancer roller unit 100, which eliminates the need for motors that were previously required to drive the screening roller and the tension help roller, thus simplifying the apparatus configuration of the optical fiber manufacturing apparatus in the pass line from the capstan 17 to the bobbin B. Furthermore, the air cylinder 120 is driven and controlled by the tension control device 21 based on the tension applied to the optical fiber G2 measured by the tension measuring unit 19, so that the tension of the optical fiber G2 becomes a predetermined tension. As a result, the tension of the optical fiber G2 can be adjusted to a predetermined tension simply by the tension control device 21 driving and controlling at least one of the air cylinders 120, making it possible to change the tension applied to the optical fiber G2 even during wire drawing.

[0042] Furthermore, by setting the tension control device 21 to a winding tension applied to the optical fiber G2 after the screening inspection is completed to a tension smaller than the tension applied to the optical fiber G2 during the screening inspection, the tension applied to the optical fiber changes without stopping the drawing of the optical fiber G2 when the screening inspection is completed, thereby improving the manufacturing efficiency of the optical fiber G2.

[0043] Furthermore, since the tension adjustment mechanism of the dancer roller unit 100 is an air cylinder 120 that applies vertical thrust to the dancer roller 110 perpendicular to the axial direction of the rotation axis 111 of the dancer roller 110, the movement direction of the dancer roller 110 is limited to one direction, vertical, and the installation layout of the tension adjustment mechanism is made space-saving, so the optical fiber manufacturing apparatus 10 can be easily miniaturized.

[0044] <Method for manufacturing optical fibers according to the first embodiment of the optical fiber manufacturing apparatus> Next, a method for manufacturing optical fibers using the optical fiber manufacturing apparatus 10 will be described.

[0045] The optical fiber manufacturing method using the optical fiber manufacturing apparatus 10 described above can be broadly divided into two main parts: (1) a screening process and (2) a normal process.

[0046] (1) Screening process In the screening process, the tension control device 21 drives the bobbin motor of the bobbin changer 20 to wind the optical fiber G2 onto the inspection bobbin Bt. In this screening process, a tension measurement step is performed in which the tension measuring unit 19 measures the screening tension applied to the optical fiber G2 while the tension control device 21 drives and controls the air cylinder 120 to apply a predetermined tension to the optical fiber G2.

[0047] If the tension applied to optical fiber G2 is higher than the predetermined screening tension as a result of the tension measurement step, it is determined that there is no quality defect in optical fiber G2, and the screening process is terminated.

[0048] (2) Normal process In the normal process, a bobbin switching step is first performed in which the winding destination of the optical fiber G2 is switched from the inspection bobbin Bt to the normal bobbin Bn, and the winding tension applied to the optical fiber G2 is set to a tension smaller than the screening tension applied to the optical fiber G2 in the screening process (when the optical fiber G2 is wound onto the inspection bobbin Bt). Then, the tension control device 21 drives the bobbin motor of the bobbin switcher 20 to wind the optical fiber G2 onto the standard bobbin Bn.

[0049] At this time, based on the tension applied to the optical fiber G2 during winding as measured by the tension measuring unit 19, the tension control device 21 drives and controls the air cylinder 120 to perform a tension adjustment step that adjusts the tension applied to the optical fiber G2.

[0050] According to the optical fiber manufacturing method configured in this way, the tension adjustment step includes a tension control device 21 that drives and controls the air cylinder 120 based on the tension applied to the optical fiber G2 measured by the tension measuring unit 19. As a result, the tension of the optical fiber is adjusted to a predetermined tension simply by the tension control device 21 driving and controlling the air cylinder 120, making it possible to change the tension applied to the optical fiber G2 even during drawing.

[0051] Furthermore, by including a bobbin switching step that switches the winding destination of the optical fiber G2 from an inspection bobbin Bt, which winds the optical fiber G2 while screening, to a normal bobbin Bn, which winds the optical fiber G2 after the screening inspection is completed, and sets the winding tension applied to the optical fiber G2 after the screening inspection is completed to a tension smaller than the tension applied to the optical fiber G2 while screening inspection is completed, the tension applied to the optical fiber G2 changes without stopping the drawing of the optical fiber G2 when the screening inspection is completed, thereby improving the manufacturing efficiency of the optical fiber G2.

[0052] <Second Embodiment of Optical Fiber Manufacturing Apparatus> Next, a second embodiment of the optical fiber manufacturing apparatus used in the optical fiber manufacturing method according to this disclosure will be described with reference to Figures 4 and 5. Figure 4 is a schematic diagram of an optical fiber manufacturing apparatus according to the second embodiment of this disclosure, and Figure 5 is a side view showing an example of the dancer roller unit shown in Figure 4. Furthermore, the optical fiber manufacturing apparatus (optical fiber manufacturing apparatus) 10A of the second embodiment is a modified version of the optical fiber manufacturing apparatus 10 of the first embodiment, with a modified dancer roller unit. Since many elements are common to the optical fiber manufacturing apparatus 10 of the first embodiment, a detailed explanation of the common items will be omitted.

[0053] As shown in Figure 5, the dancer roller unit 200 in the second embodiment consists of a dancer roller 210 for winding the optical fiber G2 and a tension adjustment mechanism 220 for adjusting the tension applied to the optical fiber G2 by the dancer roller 210. The tension adjustment mechanism 220 includes a torque-applying motor (e.g., a servo motor) 221 having a drive shaft 221a extending substantially parallel to the rotation axis 211 of the dancer roller 210 and an encoder (not shown) for detecting the rotational position of the drive shaft 221a, and an arm member 222 having one end connected to the rotation axis 211 of the dancer roller 210 and the other end connected to the drive shaft 221a of the torque-applying motor 221.

[0054] In the optical fiber manufacturing apparatus 10A described above, the tension control device 21 is electrically connected to the dancer roller unit 200, the tension measuring unit 19, and the bobbin changer 20, and controls the torque application motor 221 and the bobbin motor of the bobbin changer 20 based on the tension measurement results of the tension measuring unit 19.

[0055] With the optical fiber manufacturing apparatus 10A configured in this way, the tension adjustment mechanism of the dancer roller unit 200 includes a torque-applying motor 221 having a drive shaft 221a extending substantially parallel to the rotation axis 211 of the dancer roller 210, and an arm member 222 having one end connected to the rotation axis 211 of the dancer roller 210 and the other end connected to the drive shaft 221a of the torque-applying motor 221. As a result, when the torque-applying motor 221 is rotated, torque is applied to the dancer roller 210 via the arm member 222. Therefore, the position of the dancer roller 210 can be easily estimated from the encoder of the torque-applying motor 221, and the position of the dancer roller 210 can be detected at low cost.

[0056] <Method for manufacturing optical fibers according to a second embodiment of the optical fiber manufacturing apparatus> Next, we will explain how to manufacture optical fibers using the optical fiber manufacturing apparatus 10A.

[0057] (1) Screening process In the tension measurement step of the screening process, the tension control device 21 drives and controls the torque-applying motor 221 to apply a predetermined screening tension to the optical fiber G2, and the tension measurement unit 19 measures the tension applied to the optical fiber G2.

[0058] If the tension applied to optical fiber G2 is higher than the predetermined screening tension as a result of the tension measurement step, it is determined that there is no quality defect in optical fiber G2, and the screening process is terminated.

[0059] (2) Normal process In the normal process, a bobbin switching step is first performed in which the winding destination of the optical fiber G2 is switched from the inspection bobbin Bt to bobbin B, and the winding tension applied to the optical fiber G2 is set to a tension smaller than the screening tension applied to the optical fiber G2 in the screening process (when the optical fiber G2 is wound onto the inspection bobbin Bt). Then, the tension control device 21 drives the bobbin motor of the bobbin changer 20 to wind the optical fiber G2 onto the normal bobbin Bn.

[0060] At this time, based on the tension applied to the optical fiber G2 during winding as measured by the tension measuring unit 19, the tension control device 21 drives and controls the torque applying motor 221 to perform a tension adjustment step that adjusts the tension applied to the optical fiber G2.

[0061] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited to those described above. Furthermore, the elements of the embodiments described above can be combined to the extent that it is technically possible, and such combinations are also included within the scope of the present invention insofar as they include the features of the present invention.

[0062] For example, in the first embodiment, the tension control device 21 controlled the air cylinder 120 to adjust the tension applied to the optical fiber G2. However, to adjust the tension applied to the optical fiber G2, the tension control device 21 may control only the bobbin motor, or it may control both the bobbin motor and the air cylinder 120. Similarly, in the second embodiment, the tension control device 21 controlled the torque-applying motor 221 to adjust the tension applied to the optical fiber G2. However, to adjust the tension applied to the optical fiber G2, the tension control device 21 may control only the bobbin motor, or it may control both the bobbin motor and the torque-applying motor 221. [Explanation of Symbols]

[0063] 10, 10A ··· Optical fiber manufacturing equipment 11 ··· Wire-drawing furnace 11a ··· Core tube 11b ··· Heating element 11c ··· Gas supply unit 12 ··· Cooling unit 13 ··· Outer diameter measurement unit 14 ··· Coating unit 15 ··· Direct roller 16 ··· Induction roller 17 ··· Capstan 18 ··· Guide roller 19 ··· Tension measurement unit 20 ··· Bobbin changer 21 ··· Tension control device 100, 200 ··· Dancer roller unit 110, 210 ··· Dancer roller 111, 211 ··· Rotating shaft 120 ··· Air cylinder (tension adjustment mechanism) 121 ··· Movable part 220 ··· Tension adjustment mechanism 221 ··· Torque applying motor 221a ··· Drive shaft 222 ··· Arm member B ··· Bobbin Bt ··· Inspection bobbin Bn ··· Normal bobbin F ··· Base material feeding unit G ··· Glass base material G1 ··· Glass fiber G2 ··· Optical fiber FW ··· Fixed wall Fs ··· Fixed shaft

Claims

1. An optical fiber manufacturing apparatus that winds optical fibers, which are drawn from a drawing furnace that heats and softens a glass base material and are coated with resin, onto a bobbin, On the pass line from the capstan that takes in the optical fiber to the bobbin located downstream of the capstan, only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided. The guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, The dancer roller unit includes a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller. An optical fiber manufacturing apparatus in which at least one of the bobbin motor that rotates the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device based on the tension applied to the optical fiber measured by the tension measuring unit so that the tension applied to the optical fiber becomes a predetermined tension.

2. A bobbin switcher is provided to switch the winding destination of the optical fiber drawn from the aforementioned drawing furnace to either the bobbin that winds the optical fiber while performing a screening inspection, or the bobbin that winds the optical fiber after the screening inspection is completed. The optical fiber manufacturing apparatus according to claim 1, wherein the tension control device sets the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber during the screening inspection.

3. The optical fiber manufacturing apparatus according to claim 1 or claim 2, wherein the tension adjustment mechanism of the dancer roller unit is an air cylinder that applies vertical thrust to the dancer roller perpendicular to the axial direction of the rotation axis of the dancer roller.

4. An optical fiber manufacturing apparatus according to claim 1 or 2, wherein the tension adjustment mechanism of the dancer roller unit includes a torque-applying motor having a drive shaft extending substantially parallel to the rotation axis of the dancer roller and an encoder for detecting the rotational position of the drive shaft, and an arm member having one end connected to the rotation axis of the dancer roller and the other end connected to the drive shaft of the torque-applying motor, thereby applying a moment to the dancer roller.

5. A manufacturing apparatus for optical fibers, comprising winding a resin-coated optical fiber drawn from a drawing furnace that heats and softens a glass base material onto a bobbin, wherein only a guide roller for guiding the optical fiber, a dancer roller unit for applying tension to the optical fiber, and a tension measuring unit for measuring the tension of the optical fiber are provided on a pass line from a capstan that takes in the optical fiber to the bobbin located downstream of the capstan, the guide roller is rotatably mounted on a fixed shaft attached to a fixed wall, the dancer roller unit has a dancer roller for winding the optical fiber and a tension adjustment mechanism for adjusting the tension applied to the optical fiber by the dancer roller, and at least one of the bobbin motor that rotates the bobbin or the tension adjustment mechanism is driven and controlled by a tension control device so that the tension applied to the optical fiber is a predetermined tension, A tension measurement step in which the tension measuring unit measures the tension applied to the optical fiber, A method for manufacturing an optical fiber, comprising: a tension adjustment step in which the tension control device drives and controls at least one of the bobbin motor or the tension adjustment mechanism based on the tension applied to the optical fiber measured by the tension measuring unit.

6. The optical fiber manufacturing apparatus further includes a bobbin changer that switches the winding destination of the optical fiber drawn from the drawing furnace to either the bobbin that winds the optical fiber while performing a screening inspection or the bobbin that winds the optical fiber after the screening inspection is completed. The method for manufacturing an optical fiber according to claim 5, further comprising a bobbin switching step, which involves switching the winding destination of the optical fiber from a bobbin that winds the optical fiber while performing the screening inspection to a bobbin that winds the optical fiber after the screening inspection is completed, and setting the winding tension applied to the optical fiber after the screening inspection is completed to a tension smaller than the screening tension applied to the optical fiber while performing the screening inspection.

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