JPH09255372A - Resin coating device for optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin coating device for optical fibers capable of coating an optical fiber with a resin while preventing the occurrence of unequal thicknesses even if there is some nonuniformity in the flow of the resin heading toward the optical fiber within a coating die. SOLUTION: A fiber aligning die 27 is disposed between a nipple 25 and the coating die 26 next thereto. A resin supplying flow passage 28 for the aligning die is disposed between the nipple 25 and the fiber aligning die 27. The resin is supplied from this resin supplying flow passage 28 for the aligning die to the die hole 30 of the next coating die 26 through the die hole 29 of the fiber aligning die 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber resin coating device for coating an optical fiber with a resin.

[0002]

2. Description of the Related Art In order to prevent uneven thickness of a coating resin when coating a resin on an optical fiber with an optical fiber resin coating apparatus,
Conventionally, a device for making the resin flow uniform in the optical fiber resin coating device has been devised.

A typical example thereof has a structure in which several resin reservoirs and resin throttles are provided in the coating die.

An example thereof is shown in FIG. This optical fiber resin coating apparatus includes a nipple 1 and a coating die 2, and an optical fiber 4 that has passed through a nipple hole 3 of the nipple 1 comes into contact with a resin 6 in a die hole 5 of the coating die 2 and the optical fiber 4 is covered with the resin 6. In this case, in the die hole 5 of the coating die 2, between the resin supply port 7 and the outer resin reservoir 8a, the resin narrowing portion 9, the inner resin reservoir 8b, and between the nipple 1 and the coating die 2. The resin 6 is supplied through the resin supply channel 10 for the coating die.

[0005]

However, even with such a structure, it is practically difficult to make the circumferential flow of the resin 6 in the die holes 5 of the coating die 2 uniform. Further, when the coating die 2 is to be positioned, the optical fiber 4 is centered so as to pass through the center of the die hole 5 of the coating die 2 so that the optical fiber 4 is supplied through the nipple hole 3 which is a space. Since it is often accompanied by vibration due to the relationship between them, there is a very difficult problem.
Further, considering the processing accuracy of the coating die 2, it is difficult to make the flow of the resin 6 in the die hole 5 uniform in the circumferential direction of the optical fiber 4. Due to the nonuniform flow of the resin 6 described above, when the linear velocity is increased, the disturbance due to the nonuniform flow of the resin exceeds the centering force of the coating die 2, and the optical fiber 4 is coated. Resin 6
However, there is a problem in that the degree of uneven thickness is large.

An object of the present invention is to provide an optical fiber resin coating apparatus capable of coating resin while preventing uneven thickness even if there is some unevenness in the resin flow toward the optical fiber in the coating die. Especially.

[0007]

DISCLOSURE OF THE INVENTION The present invention is an optical fiber comprising a nipple and a coating die, and an optical fiber which has passed through the nipple hole of the nipple is coated with resin in a predetermined thickness in the die hole of the coating die. The present invention is to improve a resin coating device for a vehicle.

In the optical fiber resin coating apparatus according to the present invention, the fiber alignment die is provided between the nipple and the next coating die, and the alignment die resin is provided between the nipple and the fiber alignment die. A supply channel is provided, and the resin is supplied from the resin supply channel for the alignment die through the die hole of the fiber alignment die into the die hole of the next coating die. .

In this way, the resin is supplied into the die hole of the coating die from the die hole of the fiber alignment die directly above the resin die to the center of the die hole of the coating die, and the fiber adjustment is performed. A vertical circulating flow is generated around the optical fiber in the die hole of the core die, and the circulating flow is substantially uniformed in the circumferential direction of the optical fiber. Also,
With such a structure, the resin flow in the confluence of the optical fiber and the resin and the circulating flow of the resin in the taper portion in the die hole of the coating die can be separated by the fiber alignment die, and the upper and lower resins can be separated. It is possible to prevent mutual interference of the flows. Further, since the resin is supplied to the die hole of the fiber aligning die from the resin supply flow path for the aligning die, the optical fiber passes through the die hole filled with the resin, the vibration is attenuated by the resin, and the resin Since the optical fiber is aligned to some extent in the die hole of the coating die and enters the die hole of the next coating die, even if there is some unevenness in the resin flow in the die hole of the coating die, it is canceled. The resin can be coated while preventing the occurrence of uneven thickness. Therefore, even if the linear velocity of the optical fiber is increased, the resin can be coated while preventing uneven thickness.

In this case, it is preferable to provide a resin supply passage for the coating die between the fiber alignment die and the subsequent coating die, separately from the resin supply passage for the centering die.

In this way, when the resin supply is started,
It is possible to prevent air from forming in the outer periphery of the entrance of the die hole of the coating die under the fiber alignment die.
Therefore, it is possible to prevent air from being caught in the coating resin. Further, the resin pressure in the die hole of the coating die can be adjusted by the size of the resin supply channel for the coating die, and the resin can be coated at the optimum pressure.

Further, according to the present invention, the nipple and the N-stage coating die are provided, and the optical fiber passing through the nipple hole of the nipple is coated with N layers of resin at a predetermined thickness in the die holes of the N-stage coating die. The resin coating device for an optical fiber is targeted for improvement.

In the optical fiber resin coating apparatus according to the present invention, the fiber alignment die is provided between the nipple and the subsequent coating die, and the alignment die resin is provided between the nipple and the fiber alignment die. A supply flow path is configured, and the resin is supplied from the resin supply flow path for the centering die through the die hole of the fiber centering die into the die hole of the next coating die. To do.

In this way, the resin is supplied from the die hole of the fiber alignment die to the center of the die hole of the next coating die, and the periphery of the optical fiber is surrounded by the die hole of the fiber alignment die. A vertical circulating flow occurs in the optical fiber, and the circulating flow is substantially uniform in the circumferential direction of the optical fiber. Further, with such a structure, the resin flow in the confluence portion of the optical fiber and the resin and the circulating flow of the resin in the taper portion in the die hole of the coating die can be separated by the fiber alignment die. It is possible to prevent mutual interference of the resin flows. Further, since the resin is supplied to the die hole of the fiber aligning die from the resin supply flow path for the aligning die, the optical fiber passes through the die hole filled with the resin, the vibration is attenuated by the resin, and the resin Since the optical fiber is aligned to some extent in the die hole of the coating die and enters the die hole of the next coating die, even if there is some unevenness in the resin flow in the die hole of the coating die, it is canceled. The resin can be coated while preventing the occurrence of uneven thickness. Therefore, even if the linear velocity of the optical fiber is increased, the N of the resin is prevented while preventing the occurrence of uneven thickness.
Layer coating can be performed.

In this case as well, it is preferable to provide a resin supply channel for the coating die between the fiber centering die and the next coating die separately from the resin supply channel for the fiber alignment die.

In this way, when the resin supply is started,
It is possible to prevent air from forming in the outer periphery of the entrance of the die hole of the coating die under the fiber alignment die.
Therefore, it is possible to prevent air from being caught in the coating resin. Further, the resin pressure in the die hole of the coating die can be adjusted by the size of the resin supply channel for the coating die, and the resin can be coated at the optimum pressure.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Example) This example shows an example in which the resin coating device for an optical fiber of the present example is applied to the optical fiber drawing device shown in FIG.

In the optical fiber drawing apparatus, the optical fiber preform 11 is heated and melted in the drawing furnace 12 and spun to obtain the optical fiber 4. The optical fiber 4 is cooled by the fiber cooling device 14 after passing through the outer diameter measuring device 13, and then passed through the first-stage optical fiber resin coating device 15 to coat the resin of the first layer. In addition, 16 is an optical fiber resin coating device 15
Is a die holder that supports. The outer diameter measuring device 13 measures the outer diameter of the optical fiber 4, and measures the take-up speed of the fiber take-off machine and the supply speed of the optical fiber preform 11 described later so that the outer diameter of the optical fiber 4 becomes constant. Adjust.

The obtained primary coated fiber 4A is passed through the first-stage resin curing device 17 to cure the coating resin of the primary coated fiber 4A. In the resin curing device 17, an ultraviolet lamp is used when the coating resin is an ultraviolet curing resin.

Next, the primary coated fiber 4A is passed through the second-stage optical fiber resin coating device 18 to coat the second layer resin. Reference numeral 19 denotes a die holder that supports the resin coating device 18 for the optical fiber.

The obtained secondary coated fiber 4B is cooled by the second stage coated fiber cooling device 20 and then passed through the second stage resin curing device 21 to cure the coating resin of the secondary coated fiber 4B. Let

The secondary coated fiber 4B passing through the second-stage resin curing device 21 is wound on a winding bobbin 24 via a capstan 22 as a fiber pulling machine and a guide pulley 23.

In this example, the present invention is applied to the resin coating device 15 for the optical fiber at the first stage of such an optical fiber drawing device.

The resin coating device 15 for the optical fiber is shown in FIG.
As shown in FIG. 3, a nipple 25 and a coating die 26 are provided, and a fiber alignment die 27 is provided between the nipple 25 and the next coating die 26. A resin supply channel 28 for the centering die is provided between the nipple 25 and the fiber centering die 27. The resin is supplied from the resin supply flow path 28 for the centering die through the die hole 29 of the fiber centering die 27 into the die hole 30 of the coating die 26. Further, a resin supply channel 31 for the coating die is provided between the fiber alignment die 27 and the next coating die 26.

In the resin supply passage 28 for the centering die, the resin reservoir 33 outside the resin supply port 32 and the resin throttle 3 are provided.
4, the inner resin reservoir 35, and the fiber alignment die 2
The resin is supplied through the communication hole 36 of No. 7. Further, the resin is also supplied to the coating die resin supply channel 31 via the resin reservoir 35 inside.

Such an optical fiber resin coating device 15
The optical fiber 4 is supplied through the nipple hole 37 of the nipple 25.

In this example, a part of the nipple 25 and the fiber aligning die 2 are provided in the recess 38 provided in the coating die 26.
The mutual positioning is performed by fitting the whole 7 together. In addition, the positioning between these is
It is also possible to fit and position each of the upper and lower parts.

Next, the optical fiber resin coating apparatus 1
The operation of coating the resin on the optical fiber 4 with reference numeral 5 will be described.

In this device, the resin hole 33 of the fiber aligning die 27 is inserted into the die hole 29 of the fiber aligning die 27 from the resin supply port 32, the resin throttle portion 34, the inner resin reservoir 35, the communicating hole 36, and the aligning die. The resin is supplied through the resin supply channel 28. The resin is supplied to the die hole 30 of the next coating die 26 through the die hole 29 of the fiber alignment die 27.

The resin comes into contact with the optical fiber 4 passing through the nipple hole 37 at the center of the resin supply channel 28 for the centering die. The height (thickness) of the resin supply channel 28 for the centering die is
It is optimized depending on the linear velocity of the optical fiber 4 and the viscosity of the resin (at a linear velocity of 100 to 1500 m / min and a height of about 0.3 to 2.0 mm). Next, the optical fiber 4 enters the die hole 29 of the fiber alignment die 27. Dice hole 29 of the fiber alignment die 27
Of the optical fiber 4 via the resin due to the taper portion 29a and the land portion 29b in the land portion 29b of the die hole 29.
Align almost the center. Due to this centering effect, the optical fiber 4 is formed in the flow path inside the nipple 25 and the fiber centering die 27.
The optical fiber 4 can be guided almost to the center of the die hole 29 of the fiber alignment die 27 even if the resin flow toward the side becomes uneven. In addition, the centering effect of the coating die 26 is added, and the influence of disturbance can be further reduced. Furthermore, the resin in the alignment die resin supply channel 28 and the resin in the die hole 29 of the fiber alignment die 27 can damp the vibration of the optical fiber 4.

The optical fiber guided by the centering force of the fiber centering die 27 is the fiber centering die 2
The resin enters the die hole 30 of the coating die 26 which is mechanically coaxial with the center of the resin 7, and the resin is primarily coated to a predetermined coating diameter.

When the optical fiber resin coating device 15 has such a structure, the coating die 26 has a die hole 30 in which the fiber aligning die 27 is located directly above the die hole 30.
The resin is supplied from the center of the die hole 30 of the coating die 26 to the die hole 30 of the coating die 26.
The flow of the resin in the inside in the circumferential direction and the flow of the resin in the circumferential direction of the optical fiber 4 can be made substantially uniform. In addition, with such a structure, the resin alignment flow at the junction between the optical fiber 4 and the resin and the resin circulation flow in the taper portion of the die hole 30 of the coating die 26 can be separated by the fiber alignment die 27. It is possible to prevent mutual interference between the upper and lower resin flows. Further, since the resin is supplied to the die hole 29 of the fiber alignment die 27 from the resin supply flow path 28 for the alignment die, the optical fiber 4 passes through the die hole 29 filled with the resin, and the vibration is attenuated by the resin. In addition, the optical fiber 4 is centered to some extent in the die hole 29 through the resin and enters the die hole 30 of the next coating die 26. Therefore, in the die hole 30 of the coating die 26, Even if there is some non-uniformity in the flow of the resin, it is canceled and the resin can be coated while preventing the occurrence of uneven thickness. Therefore, even if the linear velocity of the optical fiber 4 is increased, it is possible to coat the resin while preventing uneven thickness.

Further, as in this example, when the resin supply flow passage 31 for the coating die is provided between the fiber alignment die 27 and the next coating die 26, the fiber alignment die 27 is started at the start of the resin supply. Under the die hole 3 of the coating die 26
It is possible to prevent air accumulation from forming on the outer circumference of the 0 inlet. Therefore, it is possible to prevent air from being caught in the coating resin. Further, depending on the size of the resin supply flow path 31 for the coating die, the die hole 3 of the coating die 26 may be formed.
The resin pressure within 0 can be adjusted, and the resin can be coated at the optimum pressure. The height (thickness) of the resin supply flow path 31 for the coating die for this example is 0.5 to 5 when the linear velocity of the optical fiber 4 is 100 to 1500 m / min.
Adjusted to about 3.0 mm.

The outer diameter of the optical fiber 4 is controlled to 125 μm,
The die holes 30 of the coating die 26 and the second stage of the resin coating device 15 for the first stage optical fiber are arranged so that the coating diameters of the first layer and the second layer of the resin on the outer periphery are 195 μm and 250 μm, respectively. The die hole of the coating die in the optical fiber resin coating device 18 was selected, and the optical fiber 4 was drawn. Regarding the uneven thickness of the resin coating of the first layer in the first-stage resin coating device for optical fiber 15 with respect to the linear velocity, the optical fiber 4 is different between the conventional resin coating device for optical fiber and the resin coating device for optical fiber 15 of the first example. Table 1 shows the results of comparison of the eccentricities when the resin was coated on.

[0035]

[Table 1] Further, although the optical fiber resin coating device 15 shown in FIG. 2 is used as the second-stage optical fiber resin coating device 18, it is possible to similarly improve the eccentricity of the resin coatings of the first layer and the second layer. did it.

(Second Example) FIG. 3 shows a second example of the optical fiber resin coating apparatus 15 according to the present invention.

In the optical fiber resin coating apparatus 15 of the present embodiment, the resin dip prevention member 39 is inserted from the fiber alignment die 27 into the entrance of the die hole 30 of the coating die 26 to thereby cover the coating die 26. The shape of the die hole 30 on the inlet side is streamlined.

With this structure, it is possible to prevent an air pocket and resin stagnation from being formed at the entrance of the die hole 30 of the coating die 26 without providing the resin supply flow path 31 for the coating die as in the first example. can do.

(Third Example) This example shows an example in which the optical fiber resin coating apparatus of the present example is applied to the optical fiber drawing apparatus shown in FIG.

In the optical fiber drawing apparatus, the optical fiber preform 11 is heated and melted in the drawing furnace 12 and spun to obtain the optical fiber 4. After this optical fiber 4 is cooled by the fiber cooling device 14 after passing through the outer diameter measuring device 13, it is passed through the collective two-layer coating type optical fiber resin coating device 40 to remove the resin of the first layer and the second layer. To cover. Reference numeral 41 is a die holder supporting the optical fiber resin coating device 15.
The outer diameter measuring device 13 measures the outer diameter of the optical fiber 4, and measures the take-up speed of the fiber take-off machine and the supply speed of the optical fiber preform 11 described later so that the outer diameter of the optical fiber 4 becomes constant. Adjust.

The obtained secondary coated fiber 4B is passed through a plurality of resin curing devices 42 to cure the coating resin of the secondary coated fiber 4B. In the resin curing device 42, an ultraviolet lamp is used when the coating resin is an ultraviolet curing resin.

The obtained secondary coated fiber 4B is wound on a winding bobbin 24 via a capstan 22 as a fiber pulling machine and a guide pulley 23.

In the present embodiment, the present invention is applied to such a collective two-layer coating type optical fiber resin coating apparatus 40 for an optical fiber drawing apparatus.

As shown in FIG. 5, the collective two-layer coating type optical fiber resin coating device 40 includes a nipple 25 and two stages of coating dies 26 and 41. The nipple 25 and the next coating die 26 are provided. A fiber alignment die 27 is provided between and. Nipple 25 and fiber alignment die 27
A resin supply flow path 28 for a centering die is provided between and. The resin is supplied from the resin supply flow path 28 for the centering die through the die hole 29 of the fiber centering die 27 into the die hole 30 of the coating die 26.

In the resin supply flow path 28 for the centering die, the resin reservoir 33 outside the resin supply port 32 and the resin throttle 3 are provided.
4, and the resin is supplied through the inner resin reservoir 35.

The second-stage coating die 41 is arranged below the first-stage coating die 26 in an overlapping manner. The coating die 4
In the die hole 42 of No. 1, from the resin supply port 43 to the outside resin reservoir 44, the resin throttle portion 45, and the inside resin reservoir 4
The resin is supplied via 6.

Although not shown, the nipple 25, the fiber aligning die 27, and the coating dies 26 and 41 of the optical fiber resin coating device 40 of such a collective two-layer coating type are fitted with positioning irregularities on the facing surfaces. The mutual positioning is performed by a case or the like for positioning them with respect to each other.

The optical fiber 4 is supplied through the nipple hole 37 of the nipple 2 to the optical fiber resin coating device 40 having such a structure.

Next, the operation of collectively coating the optical fiber 4 with two layers of resin by the one-layer two-layer coating type optical fiber resin coating device 40 will be described.

In this apparatus, the resin hole 33 of the fiber aligning die 27 is inserted into the die hole 29 of the fiber aligning die 27 from the resin supply port 32, the resin narrowing portion 34, the inner resin reservoir 35, and the resin supply flow path for the aligning die. The resin is supplied via 28. The resin is supplied to the die hole 30 of the next coating die 26 through the die hole 29 of the fiber alignment die 27. The resin supply port 4 is provided in the die hole 42 of the second-stage coating die 41.
3, the resin is supplied through the outer resin reservoir 44, the resin throttle 45, and the inner resin reservoir 46.

The resin comes into contact with the optical fiber 4 that has passed through the nipple hole 37 at the center of the resin supply passage 28 for the centering die. The height (thickness) of the resin supply channel 28 for the centering die is
It is optimized depending on the linear velocity of the optical fiber 4 and the resin viscosity. In this example, this height was adjusted to about 0.3 to 2.0 mm according to the linear velocity. Next, the optical fiber 4 enters the die hole 29 of the fiber alignment die 27. The fiber alignment die 2
No. 7 die hole 29 and taper portion 29a and land portion 2
9b to insert the optical fiber 4 through the resin into the die hole 29
The center of the land portion 29b is aligned. Due to this centering effect, most of the adverse effects due to the non-uniformity of the resin flow in the vicinity of the nipple hole 27 can be canceled. in addition,
The eccentricity can be further reduced by the centering effect of the taper portion 29a of the fiber centering die 27. Further, the resin supply flow path 28 for the alignment die and the die hole 2 of the fiber alignment die 27.
The resin in 9 damps the vibration of the optical fiber 4.

The optical fiber 4 guided by the centering force of the fiber centering die 27 enters the die hole 30 of the first-stage coating die 26 which is mechanically coaxial with the center of the fiber centering die 27. Thus, the resin is primarily coated to a predetermined coating diameter.

The primary coated optical fiber is guided to the die hole 42 of the second coating die 41 which is mechanically coaxial with the center of the coating die 26. The die hole 42
The entered optical fiber 4 is secondarily coated with a resin to a predetermined coating diameter to form a second coated fiber 4B.

The height (thickness) of the alignment die resin supply channel 28 is optimized by the linear velocity of the optical fiber 4 and the viscosities of the resins of the first and second layers. In this example, this height was adjusted within the range of 0.5 to 3 mm depending on the linear velocity.

When the collective two-layer coating type optical fiber resin coating device 40 has such a structure, the fiber aligning die 27 immediately above the die hole 30 of the coating die 26 is provided.
The resin is supplied from the die hole 29 of the coating die 26 to the center of the die hole 30 of the coating die 26.
The resin flow in the die hole 30 in the circumferential direction and the resin flow in the circumferential direction of the optical fiber 4 can be made substantially uniform. In addition, with such a structure, the resin alignment flow at the junction between the optical fiber 4 and the resin and the resin circulation flow in the taper portion of the die hole 30 of the coating die 26 can be separated by the fiber alignment die 27. It is possible to prevent mutual interference between the upper and lower resin flows. Further, since the resin is supplied to the die hole 29 of the fiber alignment die 27 from the resin supply flow path 28 for the alignment die, the optical fiber 4 passes through the die hole 29 filled with the resin, and the vibration is attenuated by the resin. In addition, the optical fiber 4 is aligned to some extent in the die hole 29 through the resin and enters the die hole 30 of the next coating die 26. Therefore, the resin in the resin flow path near the nipple hole 37 Even if there is some non-uniformity in the flow of the resin, it is canceled and the primary coating of the resin can be performed while preventing uneven thickness.

The optical fiber 4 that has passed through the coating die 26 in the first stage and the resin in the first layer around the optical fiber 4 are in the coating die in the second stage mechanically coaxial with the coating die 26 in the first stage. Since it is guided to the die hole 42 of 41, uneven thickness of the resin coating of the second layer can be reduced.

For the above reasons, the uneven thickness of the resin coating of the first layer and the second layer can be remarkably improved.

When the fiber alignment die having the above-described structure is interposed between the first-stage coating die 26 and the second-stage coating die 41, the resin coatings of the first layer and the second layer are coated. The uneven thickness can be further reduced.

Therefore, according to this example, even if the linear velocity of the optical fiber 4 is increased, the resin can be coated while preventing the occurrence of uneven thickness.

The outer diameter of the optical fiber 4 is controlled to 125 μm,
The die holes 30 of the first-stage coating die 26 in the collective two-layer coating type optical fiber resin coating apparatus 40 are adjusted so that the coating diameters of the first and second layers of resin on the outer circumference are 198 μm and 248 μm, respectively. And the die hole 42 of the coating die 41 of the second stage were selected, and the optical fiber 4 was drawn. Regarding the uneven thickness of the resin coatings of the first layer and the second layer in the collective two-layer coating type optical fiber resin coating apparatus 40 for the linear velocity, the conventional optical fiber resin coating apparatus and the optical fiber of the third example Table 2 shows a result of comparison of eccentricity when the optical fiber 4 is coated with resin by the resin coating device 40.

[0061]

[Table 2] (Fourth example) This example shows a modification of the collective two-layer coating type optical fiber resin coating apparatus 40 shown in FIG.
The parts corresponding to those in FIG. 5 are designated by the same reference numerals.

In the collective two-layer coating type optical fiber resin coating apparatus 40 of this example, the fiber alignment die 27 and the next coating die 2 are provided separately from the resin supply flow path 28 for the alignment die.
A resin supply flow path 31 for the coating die is provided between the resin and the resin.

In the resin supply passage 31 for the coating die, the resin is supplied from the resin supply port 32 through the communication passage 47, the outer resin reservoir 48, the resin throttle 49, and the inner resin reservoir 50. Are being supplied.

Even with such a structure, the same effect as in the third example can be obtained.

Particularly as in this example, the fiber alignment die 2
If a resin supply flow path 31 for the coating die is provided between the resin 7 and the next coating die 26, the die hole 30 of the coating die 26 is provided under the fiber alignment die 27 at the start of the resin supply.
It is possible to prevent the formation of air pools on the outer circumference of the inlet of the. Therefore, it is possible to prevent air from being caught in the coating resin. Further, depending on the size of the resin supply flow path 31 for the coating die, the die hole 30 of the coating die 26 is formed.
The resin pressure inside can be adjusted, and the resin can be coated at the optimum pressure. The height (thickness) of the resin supply flow path 31 for the coating die of this example was adjusted in the range of 0.5 to 3 mm according to the linear velocity.

Even in the collective two-layer coating type optical fiber resin coating apparatus 40 shown in FIG. 5, as in the optical fiber resin coating apparatus 15 shown in FIG. 3, at the entrance of the die hole 30 of the coating die 26, By inserting the resin pool prevention member 39 from the fiber alignment die 27, the coating die 26
The shape of the die hole 30 on the inlet side may be streamlined.

With such a structure, the coating die 26
The circulation of the resin inside is smooth, and the resin does not stagnate, so there is no concern that the resin will deteriorate even after long-term use.

In the above example, the one-step taper-shaped fiber alignment die, which is the most preferable shape, is used, but the shape of the holes of the fiber alignment die is not limited to this, and for example, multistage It may have a tapered shape or a shape without a land portion.

[0069]

In the resin coating apparatus for an optical fiber according to the present invention, the resin is provided in the die hole of the coating die from the die hole of the fiber alignment die directly above the die hole to the center of the die hole of the coating die. Since it is being supplied,
It is possible to make the flow of the resin in the die hole of the coating die in the circumferential direction and the flow of the resin in the circumferential direction of the optical fiber substantially uniform. Also, due to the presence of the fiber alignment die,
It is possible to separate the resin flow in the confluence of the optical fiber and the resin from the circulating flow of the resin in the taper in the die hole of the coating die, and prevent mutual interference of the upper and lower resin flows. Further, since the resin is supplied from the resin supply flow path for the alignment die to the die hole of the fiber alignment die, the optical fiber passes through the die hole filled with the resin, the vibration is attenuated by the resin, and The optical fiber is aligned to a certain extent in the die hole through the resin and enters the die hole of the next coating die, so that there is some unevenness in the resin flow in the die hole of the coating die. Even if it is canceled, the resin can be coated while preventing uneven thickness. Therefore, even if the linear velocity of the optical fiber is increased, the resin can be coated while preventing uneven thickness.

In this case, if a resin supply flow path for the coating die is provided between the fiber aligning die and the next coating die, when the resin supply is started, the die hole of the coating die is formed under the fiber aligning die. It is possible to prevent air accumulation on the outer circumference of the inlet. Therefore, it is possible to prevent air from being caught in the coating resin. Further, the resin pressure in the die hole of the coating die can be adjusted by the size of the resin supply channel for the coating die, and the resin can be coated at the optimum pressure.

Further, according to the present invention, also in the resin coating device for the optical fiber which is provided with the nipple and the N-stage coating die and coats the resin with N layers, the fiber alignment die is provided between the nipple and the next coating die. By providing it, the same effect can be obtained.

Also in this collective N-layer coating type optical fiber resin coating apparatus, if the resin supply channel for the coating die is provided between the fiber aligning die and the next coating die, the fiber is started at the start of the resin supply. It is possible to prevent air from forming in the outer periphery of the entrance of the die hole of the coating die under the aligning die. Therefore, it is possible to prevent air from being caught in the coating resin. Further, the resin pressure in the die hole of the coating die can be adjusted by the size of the resin supply channel for the coating die, and the resin can be coated at the optimum pressure.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an example of an optical fiber drawing device using an optical fiber resin coating device of the present invention.

FIG. 2 is a vertical sectional view of a first example of a resin coating device for an optical fiber according to the present invention used in FIG.

FIG. 3 is a longitudinal sectional view of a second example of the optical fiber resin coating apparatus according to the present invention used in FIG.

FIG. 4 is a vertical sectional view showing a schematic configuration of another example of an optical fiber drawing device using the resin coating device for an optical fiber of the present invention.

5 is a vertical cross-sectional view of a third example of the resin coating device for an optical fiber according to the present invention used in FIG.

FIG. 6 is a vertical sectional view of a fourth example of the resin coating device for an optical fiber according to the present invention used in FIG.

FIG. 7 is a vertical cross-sectional view of a conventional resin coating device for an optical fiber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 nipple 2 coating die 3 nipple hole 4 optical fiber 4A primary coating fiber 4B secondary coating fiber 5 die hole 6 resin 7 resin supply port 8a outer resin reservoir 8b inner resin reservoir 9 resin throttle 10 resin for coating die Supply channel 11 Optical fiber base material 12 Drawing furnace 13 Outer diameter measuring instrument 14 Fiber cooling device 15 First stage resin coating device for optical fiber 16 Die holder 17 First stage resin curing device 18 Second stage resin coating device for optical fiber 19 Die holder 20 Coated fiber cooling device 21 Second stage resin curing device 22 Capstan 23 Guide pulley 24 Winding bobbin 25 Nipple 26 Covering die 27 Fiber aligning die 28 Resin feed flow path for aligning die 29 Dice hole 30 Dice hole 31 Resin supply channel for coating die 32 Resin supply port 33 Outside Resin accumulation part 34 resin narrowing part 35 inner resin accumulation part 36 communication hole 37 nipple hole 38 recess 39 resin accumulation prevention member 40 resin coating device for collective two-layer coating type optical fiber 41 die holder 42 resin curing device 43 resin supply Mouth 44 Outer resin reservoir 45 Resin throttle 46 Internal resin reservoir 47 Communication passage 48 Outer resin reservoir 49 Resin throttle 50 Inner resin reservoir

Claims (4)

[Claims] 1. A resin coating device for an optical fiber, comprising: a nipple and a coating die, wherein an optical fiber passing through a nipple hole of the nipple is coated with a resin having a predetermined thickness in the die hole of the coating die, A fiber aligning die is provided between the nipple and the subsequent coating die, and a aligning die resin supply flow path is provided between the nipple and the fiber aligning die, and the aligning die resin is provided. A resin coating device for an optical fiber, characterized in that the resin is supplied from a supply channel through a die hole of the fiber alignment die into the die hole of the next coating die. 2. The resin coating apparatus for an optical fiber according to claim 1, wherein a resin supply passage for a coating die is provided between the fiber aligning die and the coating die subsequent thereto. . 3. A nipple and N stages of coating dies are provided,
In an optical fiber resin coating device, an optical fiber that has passed through a nipple hole of the nipple is coated with N layers of resin in a die hole of the N-stage coating die with a predetermined thickness, respectively. A fiber alignment die is provided between the die and the die, and a resin supply flow path for the alignment die is formed between the nipple and the fiber alignment die. A resin coating device for an optical fiber, characterized in that the resin is supplied into a die hole of the next coating die through a die hole of a core die. 4. The resin coating apparatus for an optical fiber according to claim 3, wherein a resin supply flow path for the coating die is provided between the fiber aligning die and the subsequent coating die. .