Optical fiber coating remover, optical fiber coating removal method, and coated optical fiber

Abstract

An optical fiber coating remover (1) comprises an optical fiber fixing part (50) that holds a coated optical fiber (10) in which the periphery of a glass fiber is covered with a coating, and a coating removal part (30) that is provided so as to be capable of coming into contact with and separating from the optical fiber fixing part and removes the coating of the coated optical fiber held by the optical fiber fixing part, the coating removal part (30) has a pair of removal blades (34) that hold the coating of the coated optical fiber therebetween, and in a cross section including the approach direction in which the coating removal part and the optical fiber fixing part approach each other and the direction in which the pair of removal blades hold the coating therebetween, the maximum curvature within 10 mm before and after the portion of the coated optical fiber (10) in contact with the pair of removal blades (34) in a state in which the coated optical fiber is set in the optical fiber coating remover is 0.098 or more, the units of the curvature being 1 / mm.

Description

Optical Fiber Coating Remover, Optical Fiber Coating Removal Method, and Optical Fiber Core 【0001】 The present disclosure relates to an optical fiber coating remover, an optical fiber coating removal method, and an optical fiber core. This application claims priority based on Japanese Patent Application No. 2024-218653 filed on December 13, 2024, and Japanese Patent Application No. 2024-218655 filed on December 13, 2024, and incorporates all the descriptions described in the above Japanese applications. 【0002】 Patent Document 1 discloses an optical fiber coating remover that heats the coating layer of an optical fiber core and at least one of a pair of coating removal blades. 【0003】 Patent Document 2 discloses an optical fiber coating removal method in which an auxiliary medium is arranged on the outer periphery of the coating layer of an optical fiber core. 【0004】 Patent Document 3 discloses an optical fiber coating remover in which a clearance portion is formed between a coating removal blade, a heater, and an elastic member, where the coating layer of the removed optical fiber core accumulates. 【0005】 Patent Document 4 discloses an optical fiber coating remover provided with a coating removal blade formed to accommodate coating removal of various types of optical fibers having various thicknesses. 【0006】 International Publication No. 2018 / 225679, International Publication No. 2018 / 225678, Japanese Patent Application Laid-Open No. 2021-56275, Japanese Patent Application Laid-Open No. 2018-136359 【0007】An optical fiber coating remover according to one aspect of the present disclosure comprises an optical fiber fixing section for holding an optical fiber core whose periphery is covered by a coating, and a coating removal section provided so as to be able to move toward and away from the optical fiber fixing section for removing the coating of the optical fiber core held by the optical fiber fixing section, wherein the coating removal section has a pair of removal blades for gripping the coating of the optical fiber core, and in a cross-section including the approach direction in which the coating removal section and the optical fiber fixing section approach each other and the gripping direction of the pair of removal blades, the maximum curvature within 10 mm before and after the portion of the optical fiber core that contacts the pair of removal blades when the optical fiber core is set in the optical fiber coating remover is 0.098 or more. The unit of curvature is 1 / mm. 【0008】 Figure 1 is a cross-sectional view of the optical fiber core in a direction perpendicular to the longitudinal direction according to this embodiment. Figure 2 is a perspective view illustrating the configuration of the optical fiber coating remover according to this embodiment. Figure 3 is a perspective view showing the optical fiber holder fixing part of the optical fiber coating remover in Figure 2 separated from the coating remover body. Figure 4 is a perspective view showing the state in which the coating has been removed from the optical fiber core set in the optical fiber coating remover in Figure 2. Figure 5 is a schematic diagram showing a part of the configuration of the optical fiber coating remover according to the first embodiment. Figure 6 is the pressure distribution when the part of the optical fiber core that contacts the pair of removal blades is not curved. Figure 7 is the pressure distribution when the part of the optical fiber core that contacts the pair of removal blades shown in Figure 5 is curved. Figure 8 is a schematic diagram showing a part of the configuration of the optical fiber coating remover according to Modification 1 of the first embodiment. Figure 9 is the pressure distribution applied to the optical fiber core by the removal blades in the configuration of Figure 8. Figure 10 is a schematic diagram showing a part of the configuration of the optical fiber coating remover according to Modification 2 of the first embodiment. Figure 11 shows a schematic view of the pair of removal blades, the upper base, and the lower base from the front. Figure 12 is a schematic diagram showing a part of the configuration of an optical fiber coating remover according to the second embodiment. Figure 13 is a schematic diagram showing a part of the configuration of an optical fiber coating remover according to a modified example 1 of the second embodiment. 【0009】Optical fiber coating removers improve coating removal efficiency by using heating elements, auxiliary media, or creating relief areas for the removed coating layer. However, there was still room for improvement in the coating removal efficiency of optical fibers. 【0010】 This disclosure aims to provide an optical fiber coating remover, an optical fiber coating removal method, and an optical fiber core that can improve the coating removal performance of optical fiber cores and enable efficient coating removal work. 【0011】 According to this disclosure, it is possible to provide an optical fiber coating remover, an optical fiber coating removal method, and an optical fiber core that can improve the coating removal performance of optical fiber cores and perform coating removal work well. 【0012】 First, embodiments of the present disclosure will be listed and described. (1) An optical fiber coating remover according to one aspect of the present disclosure comprises an optical fiber fixing part that holds an optical fiber core whose periphery is covered by a coating, and a coating removal part that is provided so as to be able to move toward and away from the optical fiber fixing part and removes the coating of the optical fiber core held by the optical fiber fixing part, wherein the coating removal part has a pair of removal blades that grip the coating of the optical fiber core, and in a cross section including the approach direction in which the coating removal part and the optical fiber fixing part approach each other and the gripping direction of the pair of removal blades, the maximum curvature within 10 mm before and after the portion of the optical fiber core that contacts the pair of removal blades when the optical fiber core is set in the optical fiber coating remover is 0.098 or more. The unit of curvature is 1 / mm. 【0013】 With this configuration, because the optical fiber core is curved, the removal blade bites into the insulation of the optical fiber core at an angle, making it easier for the removal blade to bite into the insulation. Therefore, the ability to remove the insulation from the optical fiber core is improved, and the insulation removal work can be performed smoothly. 【0014】(2) In (1) above, the thickness of the tip of each of the pair of removal blades is 20 μm or more and 40 μm or less, and the clearance between the two removal blades when the two removal blades of the pair of removal blades are closest together may be 126 μm or more and 136 μm or less. 【0015】 This configuration prevents a decrease in the strength of the removal blade, allows the removal blade to easily penetrate the coating, and makes it less likely for the removal blade to come into contact with the glass fiber. 【0016】 (3) In (1) or (2) above, the pair of removal blades has a lower removal blade that contacts the optical fiber core from below, the coating removal section includes a mounting surface on which the optical fiber core is placed, and has a heating section that heats the coating of the optical fiber core, and the distance between the lower removal blade and the heating section may be 100 μm or less. 【0017】 With this configuration, the heating element and the removal blade are close together, so the heated optical fiber core comes into contact with the removal blade without cooling down, making it easier to remove the coating. 【0018】 (4) In any of (1) to (3) above, the optical fiber fixing portion has a main body portion including a mounting surface on which the optical fiber core is placed, and a lid portion that sandwiches the optical fiber core between itself and the main body portion, and the coating removal portion includes a mounting surface on which the optical fiber core is placed, and has a heating portion that heats the coating of the optical fiber core, and in the cross-section, with reference to a virtual line that passes through the center of the clearance between the two removal blades of the pair of removal blades when the two removal blades of the pair are closest together, and extends in the approaching direction in which the coating removal portion and the optical fiber fixing portion approach, the mounting surface of the main body portion is located within a range of 200 μm to 600 μm in the direction closer to the lid portion than the reference, and the mounting surface of the heating portion may be located within a range of 80 μm to 200 μm in the direction further away from the lid portion than the reference. 【0019】With this configuration, by positioning the mounting surface of the main body relative to the reference within the above range, the removal blade closer to the lid of the two removal blades can easily bite into the coating, and it is possible to prevent the glass fiber from breaking due to contact with the removal blade. Furthermore, by positioning the mounting surface of the heating element relative to the reference within the above range, it is possible to prevent the glass fiber from breaking due to contact with the removal blade. Therefore, the coating removal performance of optical fiber cores is improved, and the coating removal work can be performed smoothly. 【0020】 (5) In any of (1) to (4) above, the coating removal section comprises a first base to which one of the pair of removal blades is attached, and a second base to which the other of the pair of removal blades is attached, wherein the first base and the second base each have contact surfaces that abut each other, and the imaginary line passing through the center of the clearance between the two removal blades in the closest position of the pair of removal blades along the contact surface may be offset from the contact surface in the clamping direction of the pair of removal blades. 【0021】 With this configuration, the distance from the contact surface to one removal blade and the distance from the contact surface to the other removal blade are different, so when the optical fiber core is sandwiched between the pair of removal blades, the amount of biting into the coating by the removal blades can be made different. 【0022】(6) In any of (1) to (5) above, the optical fiber fixing portion has a main body portion including a mounting surface on which the optical fiber core is placed, and a lid portion that sandwiches the optical fiber core between itself and the main body portion, and the coating removal portion includes a mounting surface on which the optical fiber core is placed, and has a heating portion that heats the coating of the optical fiber core, and in the cross-section, with reference to a virtual line that passes through the center of the clearance between the two removal blades of the pair of removal blades when the two removal blades of the pair are closest together, and extends in the approaching direction in which the coating removal portion and the optical fiber fixing portion approach, the mounting surface of the main body portion is located within a range of 100 μm to 600 μm in the direction closer to the lid portion than the reference, and the mounting surface of the heating portion may be located within a range of 0 μm to 150 μm in the direction further away from the lid portion than the reference. 【0023】 With this configuration, by positioning the mounting surface of the main body relative to the reference within the above range, the removal blade closer to the lid of the two removal blades can easily bite into the coating, and it is possible to prevent the glass fiber from breaking due to contact with the removal blade. Furthermore, by positioning the mounting surface of the heating element relative to the reference within the above range, it is possible to prevent the glass fiber from breaking due to contact with the removal blade. Therefore, the coating removal performance of optical fiber cores is improved, and the coating removal work can be performed smoothly. 【0024】 (7) In any of (1) to (6) above, the aforementioned surface of the heating section may be located within a range of 0 μm to 50 μm in the direction away from the lid portion than the standard. 【0025】With this configuration, both ends of the portion of the optical fiber core sandwiched between the pair of removal blades are bent toward the cover, causing the optical fiber core to form a V-shape with the portion sandwiched between the pair of removal blades as the center. That is, the optical fiber core extends diagonally downward from the optical fiber fixing part toward the pair of removal blades, and also extends diagonally downward from the heating part toward the pair of removal blades. Therefore, the tips of the removal blades located inside the V-shaped optical fiber core become more likely to bite into the coating not only at the end near the optical fiber fixing part, but also at the end near the heating part. 【0026】 (8) In any of (1) to (7) above, the clearance between the two removal blades of the pair of removal blades when they are closest together is 140 μm or less, and may be greater than the outer diameter of the glass fiber. 【0027】 With this configuration, the removal blade can easily penetrate the coating, while making it less likely for the removal blade to come into contact with the glass fiber. 【0028】 (9) A method for removing the coating of an optical fiber according to one aspect of the present disclosure, wherein the optical fiber core, whose periphery is covered by a coating, is held by an optical fiber fixing part of an optical fiber coating remover, the coating of the optical fiber core is gripped and damaged by a pair of removal blades of the coating removal part, and the coating of the optical fiber core is removed by moving the coating removal part toward and toward the optical fiber fixing part, wherein the optical fiber core is set in the optical fiber coating remover such that, in a cross section including the approach direction in which the coating removal part and the optical fiber fixing part approach each other and the gripping direction of the pair of removal blades, the maximum curvature within 10 mm before and after the part of the optical fiber core that contacts the pair of removal blades is 0.098 or more. The unit of curvature is 1 / mm. 【0029】 With this method, because the optical fiber core is curved, the removal blade bites into the insulation of the optical fiber core at an angle, making it easier for the removal blade to bite into the insulation. Therefore, the ability to remove the insulation from the optical fiber core is improved, and the insulation removal work can be performed smoothly. 【0030】 (10) A method for removing the coating of an optical fiber according to one aspect of the present disclosure involves placing an optical fiber core, whose periphery is covered by a coating, on the mounting surface of the main body of the optical fiber fixing unit, and holding the optical fiber core between the optical fiber fixing unit and the lid, heating the coating of the optical fiber core, which is placed on the mounting surface of the heating unit of the coating removal unit with the heating unit, and using a pair of removal blades of the coating removal unit to grip the coating of the optical fiber core and scratch the coating, and moving the coating removal unit toward and away from the optical fiber fixing unit to remove the coating of the optical fiber core. In the optical fiber coating removal method, the optical fiber fixing part and the heating part are arranged such that, with reference to a virtual line that passes through the center of the clearance between the two removal blades of the pair of removal blades when the two removal blades are closest together and extends in the approach direction in which the coating removal part and the optical fiber fixing part approach each other, the mounting surface of the main body of the optical fiber fixing part is located within a range of 100 μm to 600 μm in the direction closer to the lid than the reference, and the mounting surface of the heating part is located within a range of 0 μm to 150 μm in the direction further away from the lid than the reference. 【0031】 This method allows the mounting surface of the main body to be positioned within the above range relative to the reference, making it easier for the removal blade closer to the lid to bite into the coating, while preventing the glass fiber from breaking due to contact with the blade. Furthermore, positioning the mounting surface of the heating element within the above range relative to the reference prevents the removal blade from breaking due to contact with the glass fiber. Therefore, the coating removal performance of optical fiber cores is improved, and the coating removal work can be performed smoothly. 【0032】 (11) An optical fiber core according to one aspect of the present disclosure is an optical fiber core from which a portion of the coating has been removed using an optical fiber coating remover described in any of (1) to (8) above. 【0033】 This configuration makes it possible to provide optical fiber cores with the coating removed in good condition. 【0034】Specific examples of optical fiber coating removers and optical fiber coating removal methods according to embodiments of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the claims, as indicated by the claims. 【0035】 (Optical Fiber Core) Figure 1 is a cross-sectional view of an optical fiber core 10 from which the coating has been removed by the optical fiber coating remover according to this embodiment. As shown in Figure 1, the optical fiber core 10 has a glass fiber 11 and a coating layer 12. The glass fiber 11 includes a core 11A that propagates light and a cladding 11B that confines the light. 【0036】 The coating layer 12 is formed of a resin material to protect the glass fiber 11. In this example, the coating layer 12 has a primary resin layer 12A that covers the cladding 11B and a secondary resin layer 12B that covers the primary resin layer 12A. As the resins constituting the primary resin layer 12A and the secondary resin layer 12B, for example, polyolefin resins, fluororesins, urethane (meth)acrylate resins, etc., can be used. 【0037】 An ink layer 13 for identification may be added around the coating layer 12. The coating layer 12 and the ink layer 13 correspond to the coating of the optical fiber core 10 of this disclosure. 【0038】 A typical optical fiber core 10 has, for example, a glass fiber diameter of about 125 μm and an outer diameter of about 250 μm. The optical fiber coating remover according to this embodiment can suitably remove coatings from optical fiber cores 10 with smaller outer diameters than typical ones, for example, optical fiber cores 10 with a glass fiber diameter of 80 μm to 125 μm and an outer diameter of 100 μm to 210 μm. 【0039】(Optical Fiber Coating Remover) Next, the optical fiber coating remover 1 according to the present embodiment will be described with reference to FIGS. 2 to 4. FIG. 2 is a perspective view illustrating the configuration of the optical fiber coating remover 1 according to the present embodiment. FIG. 3 is a perspective view showing a state where the optical fiber holder fixing portion 2 of the optical fiber coating remover 1 in FIG. 2 is separated from the coating remover main body 3. 【0040】 As shown in FIG. 2, the optical fiber coating remover 1 has an optical fiber holder fixing portion 2 and a coating remover main body 3. 【0041】 The optical fiber holder fixing portion 2 is connected to the coating remover main body 3. As shown in FIGS. 2 and 3, the optical fiber holder fixing portion 2 is provided so as to be positionally changeable to approach or separate from the coating remover main body 3. 【0042】 Specifically, the optical fiber holder fixing portion 2 is configured to be freely slidable with respect to the coating remover main body 3. The optical fiber holder fixing portion 2 has two slide shafts 21 extending to the coating remover main body 3. The slide shaft 21 is slidably inserted into the sliding hole 3A of the coating remover main body 3. Here, the direction in which the optical fiber holder fixing portion 2 is separated from the coating remover main body 3, that is, the direction in which the optical fiber core wire 10 is pulled out, is referred to as the front of the optical fiber coating remover 1. Also, the direction in which the optical fiber holder fixing portion 2 approaches the coating remover main body 3 is referred to as the rear of the optical fiber coating remover 1. 【0043】 The optical fiber holder fixing portion 2 has a holder mounting portion 22 and a holder pressing lid 23. The holder pressing lid 23 is provided on the upper part of the holder mounting portion 22 so as to be openable and closable. 【0044】 The coating remover main body 3 has a coating removal portion 30. The coating removal portion 30 is disposed at the end to which the optical fiber holder fixing portion 2 is connected. The coating removal portion 30 has an optical fiber mounting portion 31 and an optical fiber pressing lid 32. The optical fiber pressing lid 32 is provided on the upper part of the optical fiber mounting portion 31 so as to be openable and closable. 【0045】The optical fiber holding lid 32 has a plate-shaped optical fiber holding medium 33 at its central part. The optical fiber holding medium 33 sandwiches the optical fiber core wire 10 between it and the optical fiber mounting part 31. The optical fiber holding medium 33 is formed of, for example, silicon rubber. 【0046】 The coating removing part 30 has a pair of removing blades 34 and a pair of base bodies 35. The pair of removing blades 34 make incisions in the coating layer 12 and the ink layer 13 of the optical fiber core wire 10 arranged in the coating removing part 30. 【0047】 The pair of removing blades 34 has an upper removing blade 34A and a lower removing blade 34B. The upper removing blade 34A contacts the optical fiber core wire 10 from above. The lower removing blade 34B contacts the optical fiber core wire 10 from below. 【0048】 The pair of base bodies 35 has an upper base body 35A and a lower base body 35B. The upper removing blade 34A is provided on the upper base body 35A. The lower removing blade 34B is provided on the lower base body 35B. The upper base body 35A is fixed to the front surface of the optical fiber holding lid 32 with screws. The lower base body 35B is fixed to the front surface of the optical fiber mounting part 31 with screws. 【0049】 The coating removing part 30 has a heating part 36. The heating part 36 is arranged on the upper surface of the optical fiber mounting part 31. The heating part 36 has a plate-shaped heater 37 and a heater support member 38 on which the heater 37 is mounted. A heater energization switch (not shown) that is turned ON / OFF by the opening and closing of the optical fiber holding lid 32 is provided in the coating removing part 30. When the optical fiber holding lid 32 is closed, this heater energization switch turns ON and power is supplied to the heater 37. 【0050】The coating stripper body 3 has a power supply unit 40. The power supply unit 40 has a removable cover 41 and an operating unit 42 with various switches. Inside the power supply unit 40 is a circuit board (not shown) that controls the supply of current to the heater 37. The power supply unit 40 can accommodate four to eight 1.2-volt to 1.5-volt batteries as an internal power source. A power cord 43 (see Figure 4) can be inserted into the power supply unit 40, and by inserting the power cord 43, power can be supplied from an external power source. 【0051】 Figure 4 is a perspective view showing the state after the coating (coating layer 12 and ink layer 13) has been removed from the optical fiber core 10 set in the optical fiber coating remover 1 shown in Figure 2. 【0052】 As shown in Figure 4, the optical fiber stripper 1 has an optical fiber holder 50. The optical fiber holder 50 holds the optical fiber core 10 from which the coating at the end is to be removed. By adjusting the mounting position of the optical fiber holder 50 on the optical fiber core 10, the length of the portion of the optical fiber core 10 from which the coating is to be removed can be determined. The optical fiber holder 50 corresponds to the optical fiber fixing portion of this disclosure. 【0053】 The optical fiber holder 50, which holds the optical fiber core 10, is placed on the holder mounting section 22 of the optical fiber holder fixing section 2. With the optical fiber holder 50 placed on the holder mounting section 22, the holder retaining cover 23 is closed, thereby holding the optical fiber holder 50 in place on the optical fiber holder fixing section 2. 【0054】 (First Embodiment) Figure 5 is a schematic diagram showing a part of the configuration of the coating removal section 30 of Figure 2 according to the first embodiment, and shows a cross-section in the longitudinal direction of the optical fiber core 10 that is held by the coating removal section 30. Figure 5 shows the optical fiber retaining cover 32 in a closed state. In addition, components other than the optical fiber holder 550, optical fiber retaining medium 33, pair of removal blades 34, and heater 37 are not shown. 【0055】The longitudinal cross-section of the optical fiber core 10 corresponds to the cross-section including the direction in which the optical fiber holder 50 approaches the coating removal portion 30 and the direction in which the pair of removal blades 34 grip the fiber. Note that hatching has been omitted in Figure 5 for the sake of simplicity. 【0056】 As shown in Figure 5, the pair of removal blades 34 are formed such that, for example, the thickness D1 of the tip of the upper removal blade 34A and the thickness D2 of the tip of the lower removal blade 34B are the same. In this specification, "thickness of the tip of the removal blade 34" means the thickness of the removal blade 34 in the direction that moves the optical fiber holder fixing part 2 toward or away from the coating removal device body 3 (forward or backward in Figure 5). 【0057】 As shown in Figure 5, when the optical fiber retaining cover 32 (see Figure 4) is closed, the upper removal blade 34A and the lower removal blade 34B are closest together, and the clearance between the upper removal blade 34A and the lower removal blade 34B is minimized. At this time, the upper removal blade 34A and the lower removal blade 34B sandwich the coating of the optical fiber core 10 from above and below, biting into the coating of the optical fiber core 10, and making cuts in the coating. In Figure 5, the clearance between the two removal blades 34 when the two removal blades 34 are closest together is shown as L1, and will be referred to as "clearance L1 between the two removal blades 34" in the following explanation. 【0058】 In this specification, "clearance between two removal blades" means the distance between the two removal blades 34 in the direction in which they approach each other (upward and downward in Figure 5). 【0059】 The heater 37 has a heating surface 37A. The portion of the optical fiber core 10 to be stripped of its coating is placed on the heating surface 37A. As shown in Figure 5, when the optical fiber retaining cover 32 is closed, the optical fiber core 10 is sandwiched between the optical fiber retaining medium 33 and the heating surface 37A of the heater 37 and heated by the heater 37. The heating surface 37A corresponds to the mounting surface of the heating unit 36 ​​of this disclosure. 【0060】The heater 37 is positioned near the lower removal blade 34B. For example, the heater 37 is positioned such that the distance between the lower removal blade 34B and the heater 37 in the direction in which the optical fiber holder fixing part 2 approaches the coating removal part 30 is 100 μm or less. In this example, the heater 37 is adjacent to the lower removal blade 34B. By positioning the heater 37 near the lower removal blade 34B in this way, the coating of the heated optical fiber core 10 does not cool down before coming into contact with the pair of removal blades 34, making it easier to remove the coating. 【0061】 The optical fiber stripper 1 is configured to bend in the portion where the optical fiber core set in the optical fiber stripper 1 contacts at least one pair of stripping blades. Specifically, the optical fiber stripper 1 is configured such that the maximum curvature in a range of 10 mm before and after the portion of the optical fiber core set in the optical fiber stripper 1 that contacts the pair of stripping blades is 0.098 or greater. On the other hand, the maximum value of the curvature of the optical fiber core within the above range may be configured to be 0.5 or less. The unit of curvature is 1 / mm. 【0062】 Furthermore, the optical fiber stripper 1 may be configured to curve not only within 10 mm before and after the part of the optical fiber core 10 that contacts the pair of stripping blades 34, but also in the surrounding area. The surrounding area refers, for example, to the area within 20 mm before and after the part of the optical fiber core that contacts the pair of stripping blades 34, but further than 10 mm before and after. The maximum curvature of the optical fiber core in the area within 20 mm before and after the part of the optical fiber core that contacts the pair of stripping blades 34 may be 0.098 or more, and the maximum value of the curvature may be 0.5 or less. The unit of curvature is 1 / mm. 【0063】 For example, by setting the positions of the optical fiber holder 50 and heater 37 relative to the pair of removal blades 34, the portion of the optical fiber core 10 that contacts the pair of removal blades 34 can be curved. 【0064】In this example, the heating surface 37A of the heater 37 is positioned above the lower removal blade 34B when the pair of removal blades 34 are closest together. As a result, the optical fiber core 10 is curved such that the front portion is lower than the rear portion in the portion behind the part that contacts the pair of removal blades 34. 【0065】 The optical fiber holder 50 has a holder body portion 51 and a holder cover portion 52. The holder body portion 51 has a mounting surface 51A on which the optical fiber core 10 is placed. The holder cover portion 52 has a contact surface 52A that contacts the optical fiber core 10. The optical fiber holder 50 holds the optical fiber core 10 by sandwiching it from above and below with the holder body portion 51 and the holder cover portion 52. The holder body portion 51 and the holder cover portion 52 correspond to the body portion and cover portion of this disclosure. The mounting surface 51A is configured to be located above the lower removal blade 34B. As a result, the optical fiber core 10 is curved such that the front portion is above the rear portion in front of the portion that contacts the removal blade 34. 【0066】 (Method for removing optical fiber coating) Next, a method for removing the coating of an optical fiber using the optical fiber coating remover 1 will be described. 【0067】 First, the operator slides the optical fiber holder fixing part 2 of the optical fiber stripper 1 toward the stripper body 3, and with it close to the stripper body 3 (see Figure 2), opens the holder retaining cover 23 and the optical fiber retaining cover 32. 【0068】 Next, the worker sets the optical fiber holder 50, to which the optical fiber core 10 is attached, onto the holder mounting section 22 of the optical fiber holder fixing section 2 (see Figure 4). At this time, as shown in Figure 5, the tip portion of the optical fiber core 10 attached to the optical fiber holder 50 that is located behind the optical fiber holder 50 (the portion to be stripped of its coating) is placed on the heating surface 37A of the heater 37. 【0069】Next, the operator closes the holder retaining cover 23 of the optical fiber holder fixing part 2 and the optical fiber retaining cover 32 of the coating removal device body 3. When the optical fiber retaining cover 32 is closed, as shown in Figure 5, the upper removal blade 34A and the lower removal blade 34B move closer to each other and cut into the coating of the optical fiber core 10. 【0070】 Furthermore, when the optical fiber retaining cover 32 is closed, the heater power switch is turned ON, and the heater 37 is energized. As a result, the coating layer 12 of the portion of the optical fiber core 10 to be removed, which is placed on the heating surface 37A of the heater 37, is rapidly heated and softened by the heater 37. 【0071】 Next, the operator confirms, using the indicator LED on the control unit 42, that the coating on the optical fiber core 10 has reached the optimal temperature for coating removal (for example, 140°C). After confirming the optimal temperature, the operator grasps the coating removal tool body 3 and the optical fiber holder fixing part 2, respectively, and slides the optical fiber holder fixing part 2 in a direction that separates it from the coating removal tool body 3 (forward in Figure 5). 【0072】 In this way, the glass fiber 11 near the end of the optical fiber core 10 is pulled out from the coating layer 12, and only the coating layer 12 and ink layer 13 that have been heated and softened on the tip side of the cuts made by the pair of removal blades 34 are removed, exposing the glass fiber 11. When the coating removal work is completed, the worker opens the optical fiber retaining cover 32, the heater power switch turns OFF, and power to the heater 37 is stopped. 【0073】 According to the optical fiber coating remover 1 and optical fiber coating removal method described herein, the optical fiber core 10 is curved such that the curvature in the area within 10 mm before and after the portion of the optical fiber core 10 that contacts the pair of removal blades 34 is 0.098 or greater. The unit of curvature is 1 / mm. As a result, the removal blades 34 bite into the coating (coating layer 12 and ink layer 13) of the optical fiber core 10 at an angle, thereby widening the area in the coating over which stress is applied by the removal blades 34. 【0074】Figures 6 and 7 show the pressure distribution applied to the optical fiber core 10 by the pair of removal blades (two removal blades) 34 when they are closest together. Figure 6 shows the pressure distribution when the portion of the optical fiber core 10 in contact with the pair of removal blades 34 is not curved. Figure 7 shows the pressure distribution when the portion of the optical fiber core 10 in contact with the pair of removal blades 34, as shown in Figure 5, is curved. In Figures 6 and 7, the pressure intensity is shown by shades of grayscale. This pressure distribution is the result of a simulation based on a 3D model of the coating removal section 30. This simulation is not limiting to the present disclosure. 【0075】 As shown in Figure 6, when the portion of the optical fiber core 10 that contacts the pair of removal blades 34 is not curved, it can be seen that the area in the longitudinal direction of the optical fiber core 10 over which stress is applied to the coating of the optical fiber core 10 is narrow. On the other hand, as shown in Figure 7, when the portion of the optical fiber core 10 that contacts the pair of removal blades 34 is curved, it can be seen that the area in the longitudinal direction of the optical fiber core 10 over which stress is applied to the coating of the optical fiber core 10 is wide. 【0076】 Thus, with the optical fiber coating remover 1 according to this disclosure, the area over which stress is applied to the coating by the pair of removal blades 34 is wide, so the removal blades 34 can easily bite into the coating, and cracks are likely to form in the coating. Therefore, the coating removal performance of the optical fiber core 10 is improved, and the coating removal work can be performed smoothly. 【0077】 (Modification 1) Next, the optical fiber coating remover 1A according to Modification 1 of the first embodiment will be described with reference to Figure 8. Figure 8 is a schematic diagram showing a part of the configuration of the optical fiber coating remover 1A, showing the optical fiber retaining cover 32 in a closed state. Elements that are substantially the same as those described with reference to Figure 5 are given the same reference numerals, and repeated explanations are omitted. 【0078】As shown in Figure 8, the coating removal section 30 of the optical fiber coating remover 1A according to this modified example has a spacer 44. The spacer 44 has an upper spacer 44A and a lower spacer 44B. The upper spacer 44A is positioned between the upper removal blade 34A and the optical fiber holding medium 33. 【0079】 The upper spacer 44A is configured such that its lower surface is positioned above the lower surface of the optical fiber retaining medium 33. A relief section is formed where the coating of the optical fiber core 10 removed by the upper removal blade 34A, the upper spacer 44A, and the optical fiber retaining medium 33 accumulates. The lower spacer 44B is positioned between the lower removal blade 34B and the heater 37. 【0080】 In the optical fiber stripper 1A, the optical fiber core 10 set in the optical fiber stripper 1A is configured to be curved in the portion that contacts at least one pair of stripping blades 34. Specifically, the optical fiber stripper 1A is configured such that the curvature of the portion of the optical fiber core 10 set in the optical fiber stripper 1A that contacts the pair of stripping blades 34 is 0.098 or greater. The unit of curvature is 1 / mm. 【0081】 In this example, the heating surface 37A of the heater 37 is positioned below the lower removal blade 34B when the pair of removal blades 34 are closest together. As a result, the optical fiber core 10 is curved such that the front portion is higher than the rear portion in the portion that contacts the pair of removal blades 34 and the surrounding portion. 【0082】 Therefore, in the optical fiber coating remover 1A according to the modified example 1, the removal blade 34 bites into the coating of the optical fiber core 10 at an angle, so the area in the coating over which stress is applied by the removal blade 34 is widened. 【0083】 Figure 9 shows the pressure distribution applied to the optical fiber core 10 by the removal blade 34 in the structure shown in Figure 8. This pressure distribution is the result of a simulation based on a 3D model of the coating removal section 30. This simulation is not limiting to the present disclosure. 【0084】As shown in Figure 9, in the structure shown in Figure 8, compared to the case where the portion of the optical fiber core 10 that contacts the pair of removal blades 34 shown in Figure 6 is not curved, it can be seen that the area over which stress is applied to the coating of the optical fiber core 10 in the longitudinal direction of the optical fiber core 10 is wider. 【0085】 Thus, in the optical fiber coating remover 1A according to Modification 1, the area over which stress is applied to the coating by the pair of removal blades 34 is wide, so the removal blades 34 can easily bite into the coating, and cracks are likely to form in the coating. Therefore, the coating removal performance of the optical fiber core 10 is improved, and the coating removal work can be performed smoothly. 【0086】 (Variation 2) 【0087】 Next, a modified example 2 of the first embodiment of the optical fiber coating remover 1B will be described using Figure 10. Figure 10 is a schematic diagram showing a part of the configuration of the optical fiber coating remover 1B, and shows the optical fiber retaining cover 32 in a closed state. Note that components other than the optical fiber holder 50, optical fiber retaining medium 33, pair of removal blades 34, and heater 37 are not shown. Elements that are substantially the same as those described with reference to Figure 5 are given the same reference numerals, and repeated explanations are omitted. 【0088】 As shown in Figure 10, the optical fiber holder 50 is configured to be offset upward relative to the pair of removal blades 34 when the optical fiber retaining cover 32 is closed and the two removal blades 34 are closest together. That is, when the two removal blades 34 are closest together, the central axis of the optical fiber core 10 fixed to the optical fiber holder 50 is offset upward relative to the central axis of the optical fiber core 10 sandwiched between the pair of removal blades 34. 【0089】Specifically, as shown in Figure 10, the first virtual line IL1 is used as a reference, passing through the center of the clearance L1 between the two removal blades 34 and extending in the direction in which the optical fiber holder 50 approaches the coating removal section 30. The optical fiber holder 50 is configured such that the mounting surface 51A of the holder body 51 is located within a range of 200 μm to 600 μm in the direction (upward) from the reference, in the direction closer to the holder cover 52. 【0090】 Furthermore, the heater 37 is configured such that the heating surface 37A is located within a range of 80 μm to 200 μm in the direction away from the holder cover 52 (downward) from the first virtual line IL1 which is the reference. 【0091】 By setting the positions of the optical fiber holder 50, heater 37, etc., relative to the pair of removal blades 34 within the above range, the portion of the optical fiber core 10 that contacts the pair of removal blades 34 can be curved. 【0092】 Furthermore, as shown in Figure 10, since the optical fiber holder 50 is offset upward relative to the pair of removal blades 34, the optical fiber core 10 extends diagonally upward from the pair of removal blades 34 toward the optical fiber holder 50. This makes it easier for the tip of the upper removal blade 34A, which is located in the offset direction (especially the front end of the tip), to bite into the coating of the optical fiber core 10. 【0093】 However, the further the optical fiber holder 50 is upward from the pair of removal blades 34, the easier it is for the upper removal blade 34A to bite into the coating. If it is too far away, the upper removal blade 34A will get too close to the optical fiber core 10 and come into contact with the glass fiber 11, making the glass fiber 11 prone to breakage. 【0094】 In contrast, with the optical fiber coating remover 1B, by positioning the mounting surface 51A of the holder body 51 relative to the first virtual line IL1 within the above range, the upper removal blade 34A can easily bite into the coating of the optical fiber core 10, and contact of the upper removal blade 34A with the glass fiber 11 can be prevented. 【0095】Furthermore, as the heating surface 37A of the heater 37 approaches the first virtual line IL1, the optical fiber core 10 is pushed upward by the heater 37 and approaches the upper removal blade 34A. On the other hand, if the heating surface 37A of the heater 37 is too far below the first virtual line IL1, the optical fiber core 10 will get too close to the lower removal blade 34B. Therefore, by keeping the position of the heating surface 37A of the heater 37 within the above range relative to the first virtual line IL1, it is possible to prevent the removal blade 34 from coming into contact with the glass fiber 11 and causing the glass fiber 11 to break. 【0096】 In addition, in the above embodiment, modified example 1, and modified example 2, the thickness D1 and D2 of the tip of each removal blade of the pair of removal blades 34 may be 20 μm or more and 40 μm or less, and the clearance L1 between the two removal blades 34 may be 126 μm or more and 136 μm or less. 【0097】 Here, a narrower tip thickness of the removal blade 34 allows it to penetrate deeper into the coating, but if it is too narrow, the strength of the removal blade 34 decreases. In contrast, by setting the thickness of the tip of the removal blade 34 within the above range, the removal blade 34 can penetrate the coating easily, and the strength of the removal blade 34 does not decrease easily. 【0098】 Furthermore, in order to make it easier for the removal blades 34 to bite into the coating of the optical fiber core 10, it is conceivable to narrow the clearance L1 between the two removal blades 34. However, if the clearance L1 between the two removal blades 34 is too narrow, the removal blades 34 will get too close to the glass fiber 11 and come into contact with it, making the glass fiber 11 prone to breakage. 【0099】 In contrast, by defining the clearance L1 between the two removal blades 34 within the above range, the removal blades 34 can easily bite into the coating of the optical fiber core 10, and the removal blades 34 are less likely to come into contact with the glass fiber 11. 【0100】 In the first embodiment, modified example 1, and modified example 2 described above, the pair of removal blades 34 may be configured such that the amount of penetration of each removal blade 34 into the coating of the optical fiber core 10 is different. 【0101】Figure 11 shows a schematic view of the pair of removal blades 34, the upper base 35A, and the lower base 35B from the front, with the optical fiber retaining cover 32 (see Figure 4) in the closed position. 【0102】 As shown in Figure 11, the upper base 35A has a contact surface 35A1. The lower base 35B has a contact surface 35B1. The upper base 35A and the lower base 35B are configured such that their contact surfaces 35A1 and 35B1 come into contact with each other when the optical fiber retaining cover 32 (see Figure 4) is closed and they are closest to each other. 【0103】 The upper base 35A and the lower base 35B are positioned such that when the two removal blades 34 are closest together, the central axis C of the optical fiber core 10 sandwiched between the pair of removal blades 34 is located on the contact surfaces 35A1 and 35B1 that are in contact with each other. 【0104】 The upper removal blade 34A is provided on the upper base 35A such that its tip 34A1 (lower end in the figure) is located above the contact surface 35A1 of the upper base 35A. The lower removal blade 34B is provided on the lower base 35B such that its tip 34B1 (upper end in the figure) is located below the contact surface 35B1 of the lower base 35B. 【0105】 The first distance L11 between the tip 34A1 of the upper removal blade 34A and the contact surface 35A1 of the upper base 35A is formed to be different from the second distance L12 between the tip 34B1 of the lower removal blade 34B and the contact surface 35B1 of the lower base 35B. That is, the second imaginary line IL2, which passes through the center of the clearance L1 between the two removal blades 34 and runs along the contact surface, is offset in the direction in which the pair of removal blades 34 clamp each other with respect to the contact surfaces 35A1 and 35B1 that are in contact with each other. 【0106】 In this example, the first distance L11 is greater than the second distance L12, and the second virtual line IL2 is shifted upward relative to the contact surfaces 35A1 and 35B1 that are in contact with each other. 【0107】 In this specification, "the distance between the tip of the removal blade 34 and the contact surface of the base 35" means the distance in the clamping direction (upward and downward in Figure 11) of the pair of removal blades 34. 【0108】 With this configuration, since the first distance L11 and the second distance L12 are different from each other, when the optical fiber core 10 is sandwiched between the pair of removal blades 34, the amount of penetration of each removal blade 34 into the coating is different. 【0109】 For example, as shown in Figure 10, when the optical fiber core 10 extends diagonally upward from the pair of removal blades 34 toward the optical fiber holder 50, the upper removal blade 34A is more likely to bite into the coating of the optical fiber core 10 than the lower removal blade 34B. In such a case, by making the second distance L12 smaller than the first distance L11, the amount of biting into the coating of the optical fiber core 10 by the lower removal blade 34B when the optical fiber retaining cover 32 (see Figure 4) is closed becomes greater than the amount of biting into the coating of the optical fiber core 10 by the upper removal blade 34A. This improves the ease with which the lower removal blade 34B can bite into the coating. 【0110】 (Examples) Next, examples of the first embodiment of the present disclosure will be described. However, the present disclosure is not limited to the following examples. 【0111】 (Curvature of optical fiber core) Multiple optical fiber coating removers with different curvatures of the optical fiber cores sandwiched between a pair of removal blades were prepared, and the coating of the optical fiber core 10 was removed using each optical fiber coating remover, and the success rate was compared. Successful coating removal was defined as being able to remove only the coating without damaging the glass fiber 11, and no coating residue being generated around the glass fiber 11 near the cut point made by the removal blade 34. 【0112】 Ten optical fiber cores were stripped of their coatings. Those where the coating was successfully removed from all optical fiber cores (i.e., a 100% success rate) were designated as A. Those where the coating was successfully removed from 70% of all optical fiber cores (i.e., a 70% success rate) were designated as B. Those where the coating was successfully removed from 50% of all optical fiber cores (i.e., a 50% success rate) were designated as C. Those where the coating was not successfully removed from any optical fiber cores (i.e., a 0% success rate) were designated as D. The success rate results are shown in Table 1. 【0113】For the optical fiber core 10 to be stripped of its coating, an optical fiber core with an outer diameter of 125 μm for the glass fiber and an outer diameter of 165 μm for the optical fiber core was used. 【0114】 【0115】 Examples 1 to 3 are examples, and Examples 4 and 5 are comparative examples. As shown in Table 1, for Examples 1 to 3, where the curvature of the optical fiber core was 0.098 or greater, the success rate of coating removal was 75% or greater. In contrast, for Examples 4 and 5, where the curvature of the optical fiber core was 0.071 or greater, the success rate of coating removal was 50% or greater. The unit of curvature is 1 / mm. 【0116】 Multiple optical fiber strippers were prepared with different tip thicknesses D1 and D2 of the stripping blades 34, clearance L1 between the two stripping blades 34, position of the heater 37 relative to the pair of stripping blades 34, and position of the optical fiber holder 50 relative to the pair of stripping blades 34. The stripping of the optical fiber core 10 was performed using each optical fiber stripper, and the success rates were compared. The breakage rate of the glass fiber 11 was also compared. The results of the success rate and breakage rate are shown in Table 2. 【0117】 For the optical fiber core 10 to be stripped of its coating, an optical fiber core with an outer diameter of 125 μm for the glass fiber and an outer diameter of 165 μm for the optical fiber core was used. 【0118】 In Table 2, clearance refers to the clearance L1 between the two removal blades 34 when they are closest together. Heater position refers to the position of the heating surface 37A of the heater 37, and indicates how far away it is from the first virtual line IL1 of the pair of removal blades 34 in the direction closer to the lower removal blade 34B (i.e., downwards). Holder position refers to the position of the mounting surface 51A of the holder body 51 of the optical fiber holder 50, and indicates how far away it is from the first virtual line IL1 of the pair of removal blades 34 in the direction closer to the holder cover 52 (i.e., upwards). 【0119】 【0120】 Examples 1 to 13 are examples, and Examples 14 to 22 are comparative examples. As shown in Table 2, in Examples 1 to 13, the thickness of the tip of the removal blade is 20 μm or more and 40 μm or less, the clearance between the pair of removal blades is 126 μm or more and 136 μm or less, the heater position is in the range of 80 μm or more and 200 μm or less, and the holder position is in the range of 200 μm or more and 600 μm or less. In Examples 1 to 13, the success rate of coating removal was 75% or more, and the fracture rate was 5% or less. 【0121】 In contrast, in Examples 14 and 15, although the clearance between the pair of removal blades was 130 μm, the heater position was 150 μm, and the holder position was 400 μm, the thickness of the tip of the removal blade was 10 μm or 50 μm, which did not fall within the range of 20 μm to 40 μm, the fracture rate was 0%, but the success rate of coating removal was 50% or less. 【0122】 Furthermore, in Examples 16 to 18, where the thickness of the tip of the removal blade is 30 μm, the heater position is 150 μm, and the holder position is 400 μm, but the clearance between the pair of removal blades is 125 μm or 138 μm and does not fall within the range of 126 μm to 136 μm, the success rate of coating removal was 50% or less, or the breakage rate was 80%. Specifically, in Example 16, where the clearance between the pair of removal blades is 125 μm, the success rate of coating removal was 100%, but the breakage rate was 80%. In Example 17, where the clearance between the pair of removal blades is 138 μm, the breakage rate was 0%, but the success rate of coating removal was 50%. In Example 18, where the clearance between the pair of removal blades is 140 μm, the breakage rate was 0%, but the success rate of coating removal was 0%. 【0123】Furthermore, in Examples 19 and 20, where the thickness of the tip of the removal blade was 30 μm, the clearance between the pair of removal blades was 130 μm, and the holder position was 400 μm, but the heater position was not in the range of 80 μm to 200 μm, the success rate of coating removal was 0% or the breakage rate was 40%. Specifically, in Example 19, where the heater position was 60 μm, the breakage rate was 0%, but the success rate of coating removal was 0%. Also, in Example 20, where the heater position was 220 μm, the success rate of coating removal was 75%, but the breakage rate was 40%. 【0124】 Furthermore, in Examples 21 and 22, where the thickness of the tip of the removal blade was 30 μm, the clearance between the pair of removal blades was 130 μm, and the heater position was 150 μm, but the holder position was not in the range of 200 μm to 600 μm, the success rate of coating removal was 0% or the breakage rate was 60%. Specifically, in Example 21, where the holder position was 100 μm, the breakage rate was 0%, but the success rate of coating removal was 0%. Also, in Example 22, where the holder position was 700 μm, the success rate of coating removal was 100%, but the breakage rate was 60%. 【0125】 (Second Embodiment) Next, the optical fiber coating remover 1C according to the second embodiment will be described with reference to Figure 12. Figure 12 is a schematic diagram showing a part of the configuration of the optical fiber coating remover 1C, showing the optical fiber holder fixing part 2 approaching the coating removal part 30 and closing the optical fiber retaining cover 32. Components other than the optical fiber holder 50, optical fiber retaining medium 33, pair of removal blades 34, and heater 37 are not shown. Elements that are substantially the same as those in the first embodiment and its modified examples are given the same reference numerals, and repeated explanations are omitted. The method of removing the optical fiber coating using the optical fiber coating remover 1C is the same as the method of removing the optical fiber coating using the optical fiber coating remover 1 described above, and therefore the explanation is omitted. 【0126】 As shown in Figure 12, the pair of removal blades 34 are formed such that, for example, the thickness of the tip of the upper removal blade 34A and the thickness of the tip of the lower removal blade 34B are the same. 【0127】The optical fiber holder 50 is configured to be offset upward relative to the pair of removal blades 34 when the fiber retaining cover 32 is closed and the two removal blades 34 are closest together. That is, when the two removal blades 34 are closest together, the central axis of the optical fiber core 10 fixed to the optical fiber holder 50 is offset upward relative to the central axis of the optical fiber core 10 sandwiched between the pair of removal blades 34. 【0128】 Specifically, as shown in Figure 12, a virtual line IL is used as a reference, passing through the center of the clearance L1 between the two removal blades 34 and extending in the direction in which the optical fiber holder 50 approaches the coating removal section 30. The optical fiber holder 50 is configured such that the mounting surface 51A of the holder body 51 is located within a range of 100 μm to 600 μm in the direction (upward) from the reference, in the direction closer to the holder cover 52. 【0129】 The heater 37 is positioned near the lower removal blade 34B. For example, the heater 37 is positioned such that the distance between the lower removal blade 34B and the heater 37 in the direction in which the optical fiber holder fixing part 2 approaches the coating removal part 30 is 100 μm or less. In this example, the heater 37 is adjacent to the lower removal blade 34B. By positioning the heater 37 near the lower removal blade 34B in this way, the coating of the heated optical fiber core 10 does not cool down before coming into contact with the pair of removal blades 34, making it easier to remove the coating. 【0130】 The heater 37 is configured such that its heating surface 37A is located within a range of 0 μm to 150 μm in the direction away from the holder cover 52 (downward) from the reference virtual line IL. In this example, when the two removal blades 34 are closest together, the heating surface 37A of the heater 37 is located below the tip of the lower removal blade 34B. For example, when the outer diameter of the optical fiber core 10 is between 100 μm and 210 μm, the heater 37 is configured such that its heating surface 37A is located within a range of 100 μm to 150 μm in the direction away from the holder cover 52 from the reference. 【0131】As described above, according to the optical fiber coating remover 1C of the second embodiment of this disclosure, as shown in Figure 12, the optical fiber holder 50 is offset upward with respect to the pair of removal blades 34. Therefore, the optical fiber core 10 extends diagonally upward from the pair of removal blades 34 toward the optical fiber holder 50. This makes it easier for the tip of the upper removal blade 34A, which is located in the offset direction (especially the front end of the tip), to bite into the coating (coating layer 12 and ink layer 13) of the optical fiber core 10. 【0132】 However, the further the optical fiber holder 50 is upward from the pair of removal blades 34, the easier it is for the upper removal blade 34A to bite into the coating. If it is too far away, the upper removal blade 34A will get too close to the optical fiber core 10 and come into contact with the glass fiber 11, making the glass fiber 11 prone to breakage. 【0133】 In contrast, with the optical fiber coating remover 1C, by positioning the mounting surface 51A of the holder body 51 relative to the virtual line IL within the above range (a range of 100 μm to 600 μm above the reference), the upper removal blade 34A can easily bite into the coating of the optical fiber core 10, and contact of the upper removal blade 34A with the glass fiber 11 can be prevented. 【0134】 Furthermore, if the heating surface 37A of the heater 37 is too far above the virtual line IL, the optical fiber core 10 is pushed upward by the heater 37 and comes too close to the upper removal blade 34A. On the other hand, if the heating surface 37A of the heater 37 is too far below the virtual line IL, the optical fiber core 10 comes too close to the lower removal blade 34B. 【0135】 Therefore, by positioning the heating surface 37A of the heater 37 relative to the virtual line IL within the above range (a range of 0 μm to 150 μm below the reference), it is possible to prevent the removal blade 34 from coming into contact with the glass fiber 11 and causing the glass fiber 11 to break. 【0136】(Modification 1) Next, the optical fiber coating remover 1D according to Modification 1 of the second embodiment will be described with reference to Figure 13. Figure 13 is a schematic diagram showing a part of the configuration of the optical fiber coating remover 1D, and shows the optical fiber retaining cover 32 in a closed state. Elements that are substantially the same as those described with reference to Figure 12 are given the same reference numerals, and repeated explanations are omitted. 【0137】 In the modified example 1, the optical fiber coating remover 1D has a different configuration from the optical fiber coating remover 1C shown in Figure 12, in that the position of the heating surface 37A of the heater 37 is different. 【0138】 Specifically, in the optical fiber stripper 1C shown in Figure 12, when the two stripping blades 34 are closest together, the heating surface 37A of the heater 37 is located below the tip of the lower stripping blade 34B. In contrast, as shown in Figure 13, in the optical fiber stripper 1D, when the two stripping blades 34 are closest together, the heating surface 37A of the heater 37 is located above the tip of the lower stripping blade 34B. 【0139】 For example, the heater 37 is configured such that the heating surface 37A is located within a range of 0 μm to 50 μm away from the holder cover 52 in the direction of the reference virtual line IL. 【0140】 With this configuration, both ends of the portion of the optical fiber core 10 sandwiched between the pair of removal blades 34 are bent upwards towards the holder cover 52, so that the optical fiber core 10 becomes V-shaped with the portion sandwiched between the pair of removal blades 34 as the center. That is, the optical fiber core 10 extends diagonally downwards from the optical fiber holder 50 toward the pair of removal blades 34, and the optical fiber core 10 extends diagonally downwards from the heater 37 toward the pair of removal blades 34. Therefore, the tip of the upper removal blade 34A located inside the V-shaped optical fiber core 10 can easily bite into the coating not only at the end closer to the optical fiber holder 50 (front end) but also at the end closer to the heater 37 (rear end). 【0141】In addition, in the second embodiment and modified example 1 described above, the coating removal section 30 may be configured such that the clearance L1 between the two removal blades 34 is 140 μm or less and is larger than the outer diameter of the glass fiber 11. 【0142】 To make it easier for the removal blades 34 to bite into the coating of the optical fiber core 10, one could consider narrowing the clearance L1 between the two removal blades 34. However, if the clearance L1 between the two removal blades 34 is too narrow, the removal blades 34 will get too close to the glass fiber 11 and come into contact with it, making the glass fiber 11 prone to breakage. 【0143】 In contrast, by defining the clearance L1 between the two removal blades 34 within the above range, the removal blades 34 can easily bite into the coating of the optical fiber core 10, and the removal blades 34 are less likely to come into contact with the glass fiber 11. 【0144】 In the above embodiments and modifications, the configuration may be such that, when the optical fiber core 10 is set in the optical fiber stripper 1, the curvature of the portion of the optical fiber core 10 that contacts the pair of stripping blades 34 is 0.098 or greater. The unit of curvature is 1 / mm. 【0145】 For example, by setting the positions of the optical fiber holder 50 and heater 37 relative to the pair of removal blades 34 within the above range, the portion of the optical fiber core 10 that contacts the pair of removal blades 34 can be curved. 【0146】 Furthermore, the optical fiber stripper 1 may be configured to bend not only in the portion of the optical fiber core 10 that contacts the pair of stripping blades 34, but also in the surrounding portion. The portion that contacts the pair of stripping blades 34 and the surrounding portion refer to the area within, for example, 2 mm before and after the portion that contacts the pair of stripping blades 34. 【0147】 With this configuration, the portion of the optical fiber core 10 that contacts the pair of removal blades 34 is curved, so the removal blades 34 bite into the coating of the optical fiber core 10 at an angle, making it easier for the removal blades 34 to bite into the coating. 【0148】(Examples) Next, examples of the second embodiment of the present disclosure will be described. However, the present disclosure is not limited to the following examples. 【0149】 Multiple optical fiber strippers were prepared, each with different positions for the optical fiber holder fixing part 2 relative to the pair of stripping blades 34, the position of the heater 37, and the clearance L1 between the two stripping blades 34. The stripping of the optical fiber core 10 was performed using each optical fiber stripper, and the success rates were compared. The breakage rate of the glass fiber 11 was also compared. The results of the success rate and breakage rate are shown in Table 3. 【0150】 Successful coating removal means that only the coating can be removed without damaging the glass fiber 11, and that no coating residue is generated around the glass fiber 11 near the cut made by the removal blade 34. 【0151】 Ten optical fiber cores were stripped of their coatings. Those where the coating was successfully removed from all optical fiber cores (i.e., a 100% success rate) were designated as A. Those where the coating was successfully removed from 70% of all optical fiber cores (i.e., a 70% success rate) were designated as B. Those where the coating was successfully removed from 50% of all optical fiber cores (i.e., a 50% success rate) were designated as C. Those where the coating was not successfully removed from any optical fiber cores (i.e., a 0% success rate) were designated as D. 【0152】 For the optical fiber core 10 to be stripped of its coating, an optical fiber core with an outer diameter of 125 μm for the glass fiber 11 and an outer diameter of 165 μm for the optical fiber core 10 was used. 【0153】In Table 3, the heater position refers to the position of the heating surface 37A of the heater 37. The heating surface 37A of the heater 37 is defined with respect to the virtual line IL of the pair of removal blades 34, with the direction approaching the lower removal blade 34B (i.e., downward) being positive and the direction approaching the upper removal blade 34A (i.e., upward) being negative. The holder position refers to the position of the mounting surface 51D of the holder body 51 of the optical fiber holder 50, indicating how far away it is from the reference virtual line IL in the direction approaching the lid (i.e., upward). The clearance refers to the clearance L1 between the two removal blades 34 when the two removal blades 34 are closest together. 【0154】 【0155】 Examples 31 to 54 are examples, and examples 55 to 69 are comparative examples. As shown in Table 3, in examples 31 to 54, the heater position is in the range of 0 μm to 150 μm, the holder position is in the range of 100 μm to 600 μm, and the clearance between the pair of removal blades is 140 μm or less. In examples 31 to 54, the success rate of coating removal was 75% or more, and the fracture rate was 3% or less. Furthermore, in examples 31 to 42, where the heater position is in the range of 0 μm to 50 μm, the success rate of coating removal was 100%. 【0156】 In contrast, in Examples 55, 57, 59, and 61, where the clearance between the pair of removal blades was 140 μm or less, the heater position was within the range of 0 μm to 150 μm, but the holder position was at 0 μm, the fracture rate was 0%, but the success rate of coating removal was 50% or less. Furthermore, in Examples 56, 58, 60, and 62, where the clearance between the pair of removal blades was 140 μm or less, the heater position was within the range of 0 μm to 150 μm, but the holder position was at 700 μm, the success rate of coating removal was 100%, but the fracture rate was 10% or more. 【0157】Furthermore, in Example 63, where the clearance between the pair of removal blades was 140 μm or less, the holder position was at 300 μm, but the heater position was at -30 μm, the coating removal success rate was 100%, but the breakage rate was 10%. Also, in Examples 64 and 65, where the clearance between the pair of removal blades was 140 μm or less, the holder position was at 300 μm, but the heater position was at 170 μm or 200 μm, the coating removal success rate was 75%, but the breakage rate was 10% or more. 【0158】 Furthermore, in Examples 66 to 69, where the holder position was 300 μm or 600 μm and the heater position was 0 μm or more and 100 μm or less, but the clearance between the pair of removal blades was 145 μm, the fracture rate was 0%, but the success rate of coating removal was 0%. 【0159】 Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Furthermore, the number, position, shape, etc. of the components described above are not limited to the above embodiments and can be changed to a number, position, shape, etc. that is suitable for carrying out the present invention. 【0160】<Note> The following describes aspects of the present disclosure. [1] An optical fiber fixing part that holds an optical fiber core whose periphery is covered with a coating of glass fiber, and a coating removal part that is provided so as to be able to move toward and away from the optical fiber fixing part and removes the coating of the optical fiber core held by the optical fiber fixing part, wherein the optical fiber fixing part has a main body part including a mounting surface on which the optical fiber core is placed, and a lid part that sandwiches the optical fiber core between itself and the main body part, and the coating removal part has a pair of removal blades that sandwich the coating of the optical fiber core, and a heating part including a mounting surface on which the optical fiber core is placed and that heats the coating of the optical fiber core. [1] An optical fiber coating remover, wherein, in a cross-section including the approach direction between the coating removal portion and the optical fiber fixing portion and the clamping direction of the pair of removal blades, when a virtual line passing through the center of the clearance between the two removal blades when the two removal blades of the pair of removal blades are closest together, and extending in the approach direction as the coating removal portion and the optical fiber fixing portion approach, the aforementioned mounting surface of the main body portion is located within a range of 100 μm to 600 μm in the direction closer to the lid portion than the reference, and the aforementioned mounting surface of the heating portion is located within a range of 0 μm to 150 μm in the direction further away from the lid portion than the reference. [2] The optical fiber coating remover according to [1], wherein the aforementioned mounting surface of the heating portion is located within a range of 0 μm to 50 μm in the direction further away from the lid portion than the reference. [3] The optical fiber coating remover according to [1] or [2], wherein the clearance between the two removal blades when the two removal blades are closest together is 140 μm or less, and is larger than the outer diameter of the glass fiber. [4] The optical fiber stripper according to any one of [1] to [3], wherein in the cross-section, the curvature of the portion of the optical fiber core that contacts the pair of stripping blades when the optical fiber core is set in the optical fiber stripper is 0.098 or more, and the unit of curvature is 1 / mm. [5] The optical fiber stripper according to any one of [1] to [4], wherein the pair of stripping blades has a lower stripping blade that contacts the optical fiber core from below, and the distance between the lower stripping blade and the heating section is 100 μm or less.[6] An optical fiber coating removal method in which an optical fiber core, whose periphery is covered with a coating, is placed on the mounting surface of the main body of the optical fiber fixing unit, the optical fiber core is held between the optical fiber fixing unit and the lid, the coating of the optical fiber core is heated by the heating unit while the coating of the optical fiber core, which is placed on the mounting surface of the heating unit of the coating removal unit, is clamped onto the coating of the optical fiber core by a pair of removal blades of the coating removal unit and scratches the coating, and the coating removal unit is moved toward and away from the optical fiber fixing unit to remove the coating of the optical fiber core, wherein the A method for removing the coating from an optical fiber, wherein the optical fiber fixing part and the heating part are arranged such that, with reference to a virtual line that passes through the center of the clearance between the two removal blades of a pair of removal blades when the two removal blades are in their closest position, and extends in the approaching direction in which the coating removal part and the optical fiber fixing part approach each other, the aforementioned mounting surface of the main body of the optical fiber fixing part is located within a range of 100 μm to 600 μm in the direction closer to the lid than the reference, and the aforementioned mounting surface of the heating part is located within a range of 0 μm to 150 μm in the direction further away from the lid than the reference. [7] An optical fiber core from which a portion of the coating has been removed using an optical fiber coating remover according to any one of [1] to [5]. 【0161】10 Optical fiber core 11 Glass fiber 11A Core 11B Cladding 12 Coating layer 12A Primary resin layer 12B Secondary resin layer 13 Ink layer 1 Optical fiber coating remover 1A Optical fiber coating remover 1B Optical fiber coating remover 1C Optical fiber coating remover 1D Optical fiber coating remover 2 Optical fiber holder fixing part 21 Slide shaft 22 Holder mounting part 23 Holder retaining cover 3 Coating remover body 3A Sliding hole 30 Coating removal part 31 Optical fiber mounting part 32 Optical fiber retaining cover 33 Optical fiber retaining medium 34 Removal blade 34A Upper removal blade 34A1 Tip 34B Lower removal blade 34B1 Tip 35 Base 35A Upper base 35A1 Contact surface 35B Lower base 35B1 Contact surface 36 Heating section 37 Heater 37A Heating surface 38 Heater support member 40 Power supply unit 41 Cover 42 Operation unit 43 Power cord 44 Spacer 44A Upper spacer 44B Lower spacer 50 Optical fiber holder 51 Holder body 51A Mounting surface 52 Holder cover 52A Contact surface D1 Thickness of the tip of the upper removal blade D2 Thickness of the tip of the lower removal blade IL Virtual line IL1 First virtual line IL2 Second virtual line L1 Clearance between the two removal blades L11 First distance L12 Second distance

Claims

1. An optical fiber stripper comprising: an optical fiber fixing section for holding an optical fiber core whose periphery is covered with a coating; and a coating removal section provided so as to be able to move toward and away from the optical fiber fixing section for removing the coating from the optical fiber core held by the optical fiber fixing section, wherein the coating removal section has a pair of removal blades for gripping the coating from the optical fiber core, and in a cross-section including the approaching direction in which the coating removal section and the optical fiber fixing section approach each other and the gripping direction of the pair of removal blades, the maximum curvature within 10 mm before and after the portion of the optical fiber core that contacts the pair of removal blades when the optical fiber core is set in the optical fiber stripper is 0.098 or greater, and the unit of curvature is 1 / mm.

2. The optical fiber coating remover according to claim 1, wherein the thickness of the tip of each of the pair of removal blades is 20 μm or more and 40 μm or less, and the clearance between the two removal blades of the pair of removal blades when they are closest together is 126 μm or more and 136 μm or less.

3. The optical fiber coating remover according to claim 1 or claim 2, wherein the pair of removal blades have a lower removal blade that contacts the optical fiber core from below, the coating removal section includes a mounting surface on which the optical fiber core is placed, and has a heating section for heating the coating of the optical fiber core, and the distance between the lower removal blade and the heating section is 100 μm or less.

4. The optical fiber fixing portion comprises a main body portion including a mounting surface on which the optical fiber core is placed, and a lid portion that sandwiches the optical fiber core between itself and the main body portion; the coating removal portion comprises a mounting surface on which the optical fiber core is placed, and a heating portion that heats the coating of the optical fiber core; and in the cross-section, with reference to a virtual line extending in the approaching direction in which the coating removal portion and the optical fiber fixing portion approach each other, the mounting surface of the main body portion is located within a range of 200 μm to 600 μm in the direction closer to the lid portion than the reference, and the mounting surface of the heating portion is located within a range of 80 μm to 200 μm in the direction further away from the lid portion than the reference, the optical fiber coating remover according to any one of claims 1 to 3.

5. The optical fiber coating remover according to any one of claims 1 to 4, wherein the coating removal section comprises a first base to which one of the pair of removal blades is attached, and a second base to which the other of the pair of removal blades is attached, the first base and the second base each have contact surfaces that abut each other, and a virtual line passing through the center of the clearance between the two removal blades when the two removal blades of the pair of removal blades are closest together, along the contact surface, is offset relative to the contact surface in the clamping direction of the pair of removal blades.

6. The optical fiber fixing portion comprises a main body portion including a mounting surface on which the optical fiber core is placed, and a lid portion that sandwiches the optical fiber core between itself and the main body portion; the coating removal portion comprises a mounting surface on which the optical fiber core is placed, and a heating portion that heats the coating of the optical fiber core; and in the cross-section, with reference to a virtual line extending in the approaching direction in which the coating removal portion and the optical fiber fixing portion approach each other, passing through the center of the clearance between the two removal blades of the pair of removal blades when the two removal blades are closest together, the mounting surface of the main body portion is located within a range of 100 μm to 600 μm in the direction closer to the lid portion than the reference, and the mounting surface of the heating portion is located within a range of 0 μm to 150 μm in the direction further away from the lid portion than the reference, the optical fiber coating remover according to any one of claims 1 to 5.

7. The optical fiber coating remover according to claim 6, wherein the aforementioned mounting surface of the heating section is located within a range of 0 μm to 50 μm in a direction away from the lid portion than the aforementioned standard.

8. The optical fiber coating remover according to any one of claims 1 to 7, wherein the clearance between the two removal blades of the pair of removal blades when they are closest together is 140 μm or less and is greater than the outer diameter of the glass fiber.

9. A method for removing the coating of an optical fiber, wherein the optical fiber core, whose periphery is covered by a coating, is held by an optical fiber fixing part of an optical fiber coating remover, and the coating of the optical fiber core is removed by gripping the coating of the optical fiber core with a pair of removal blades of the coating removal part, damaging the coating, and moving the coating removal part toward and toward the optical fiber fixing part, wherein the optical fiber core is set in the optical fiber coating remover such that, in a cross section including the approach direction in which the coating removal part and the optical fiber fixing part approach each other and the gripping direction of the pair of removal blades, the maximum curvature within 10 mm before and after the part of the optical fiber core that contacts the pair of removal blades is 0.098 or more, and the unit of curvature is 1 / mm.

10. A method for removing the coating of an optical fiber, wherein an optical fiber core, whose periphery is covered with a coating, is placed on the mounting surface of the main body of the optical fiber fixing unit, and the optical fiber core is held between the optical fiber fixing unit and the lid, and while the coating of the optical fiber core, which is placed on the mounting surface of the heating unit of the coating removal unit, is heated by the heating unit, the coating of the optical fiber core is gripped by a pair of removal blades of the coating removal unit and damaged, and the coating removal unit is moved toward and away from the optical fiber fixing unit, wherein, with reference to a virtual line that passes through the center of the clearance between the two removal blades of the pair of removal blades when the two removal blades of the pair of removal blades are in their closest state and extends in the approach direction in which the coating removal unit and the optical fiber fixing unit approach each other, the mounting surface of the main body of the optical fiber fixing unit is located within a range of 100 μm to 600 μm in the direction toward the lid than the reference, A method for removing the coating of an optical fiber, wherein the optical fiber fixing part and the heating part are arranged such that the mounting surface of the heating part is located within a range of 0 μm to 150 μm in a direction away from the lid part from the reference.

11. An optical fiber core from which a portion of the coating has been removed using an optical fiber coating remover according to any one of claims 1 to 8.

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