JP3387403B2 - Light curing device and light curing system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocuring device and a photocuring system for curing an ultraviolet curable coating agent applied on the surface of an optical fiber.

[0002]

2. Description of the Related Art Optical fibers are often provided with a protective coating on their outer surfaces in order to prevent damage or reinforce their outer surfaces. Further, when connecting the bundled optical fibers, a coating for coloring is often applied to the surface in order to easily identify the optical fibers. And, as the coating agent, an ultraviolet curable resin is usually used,
The coating agent applied to the surface of the optical fiber is cured by a photocuring device that irradiates light including ultraviolet rays.

The photo-curing device used for such a purpose has an elliptic cylindrical reflecting mirror whose inner surface is a mirror surface, and a pair of electrodes facing each other inside, and a linear light emitting portion between both electrodes is reflected. It is composed of a long arc type discharge lamp located on the first focal axis of the mirror, and is arranged such that the discharge lamp has a vertical posture. On the other hand, the optical fiber that is the work is designed to travel from the upper side to the lower side on the second focal axis of the reflecting mirror. Then, light including ultraviolet rays of this discharge lamp is condensed on an optical fiber by an elliptic cylindrical reflecting mirror to cure the coating agent applied on the surface of the optical fiber. Such a photo-curing device is disclosed, for example, in JP-A-62-229202 and JP-A-2-1.
It is disclosed in Japanese Patent No. 11475.

[0004]

By the way, in order to improve productivity, it is required to increase the traveling speed (also referred to as a drawing speed) of an optical fiber, and recently several hundreds of them have been demanded.
The wire is drawn at a high speed of about m to 1000 m / min. Therefore, the time required for the optical fiber to pass through the photo-curing device is shortened, and the exposure time is shortened. Therefore, in order to obtain an exposure amount sufficient for curing the coating agent, it is necessary to lengthen the light emitting portion of the discharge lamp to secure the exposure time required for curing.

If the drawing speed of the optical fiber is always constant, one discharge lamp having a long light emitting section may be used in order to cope with the high drawing speed. However, the drawing speed of the optical fiber is accelerated from the start of drawing to a predetermined speed, and is decelerated from the predetermined speed to the stop. That is, the drawing speed of the optical fiber is not always constant but changes. Therefore, it becomes necessary to change the illuminance of the discharge lamp according to the change in the drawing speed of the optical fiber. Even if it is attempted to cope with this change in illuminance by switching the input power of the discharge lamp, there is a limit, and it is difficult to adjust the optimum exposure amount according to the drawing speed only by switching the input power. Further, the length of the light emitting portion of one discharge lamp is also limited, and it is difficult to manufacture a discharge lamp having a very long light emitting portion because the electric input per unit length of the arc tube is large.

For this reason, a plurality of photocuring devices are stacked to form a photocuring system, and the sum of the lengths of the light emitting portions of each discharge lamp is increased to cope with a high drawing speed of an optical fiber. When the drawing speed is slow, the discharge lamps of some devices are turned off, and the discharge lamps are sequentially turned on as the drawing speed becomes faster. Conversely, when the drawing speed becomes slower. Responds to changes in the drawing speed by sequentially turning off.

Conventionally, in the above-mentioned photo-curing system, as the discharge lamp, for example, a rod-shaped metal halide lamp having a large output of ultraviolet rays, that is, a large input power per unit length of the arc tube is used. The part is between a pair of electrodes arranged to face each other in the arc tube,
Between the tip of the electrode and the end of the discharge lamp, that is, the tube end of the arc tube, the seal part following the tube end, the base attached to the seal part, and the like are non-light emitting parts. For example, when using a metal halide lamp with a light emitting part of 250 mm,
The total length is about 350 mm, and the ratio of the light emitting portion to the entire lamp length is about 70%.

When such a discharge lamp is incorporated in a photocuring device, the ratio of the light emitting portion to the entire length of the device becomes about 60%. As described above, since the ratio of the light emitting portion of the discharge lamp to the traveling direction of the optical fiber is low, stacking a plurality of such photo-curing devices to form a photo-curing system results in an extremely large height direction of the entire system. There is a defect.

Therefore, the present invention provides a photo-curing device in which the ratio of the light-emitting portion of the discharge lamp to the total length of the device is large and a plurality of photo-curing systems are stacked so that the height of the entire system does not increase. To aim. Also,
An object of the present invention is to provide a photo-curing device capable of accurately positioning the light emitting portion of the discharge lamp on the focal axis of the reflecting mirror and adjusting the non-light emitting portion of the discharge lamp to the optimum temperature.

[0010]

In order to achieve the above object, the invention of claim 1 is such that an elliptic cylindrical reflecting mirror whose inner surface is a mirror surface and a pair of electrodes are arranged inside the arc tube so as to face each other. , The light emitting portion between the electrodes is composed of a discharge lamp located on the first focal axis of the reflecting mirror, and by the light of this discharge lamp,
In a photo-curing device that cures a coating agent applied to the surface of an optical fiber that travels on the second focal axis of a reflecting mirror, a non-light emitting portion on the end side of the electrode tip of a discharge lamp with respect to a light emitting portion between both electrodes. By bending at a substantially right angle,
The ratio of the light emitting portion of the discharge lamp to the entire length of the device is increased, and a supporting member having a V-shaped concave portion is arranged on the inner surface of the reflecting mirror, and the outer surface of the arc tube of the discharge lamp is arranged on the supporting member. The non-luminous portion is bent even if the non-luminous portion is bent by inscribed in the concave portion for positioning, and further by pressing the arc tube of the discharge lamp into the concave portion of the supporting member by the elastic member arranged at the back of the reflecting mirror. Nevertheless, the light emitting portion of the discharge lamp can be accurately positioned on the focal axis of the reflecting mirror. In this discharge lamp, for example, as in the invention of claim 2, the non-light emitting portions at both ends are bent in the same direction on the same plane.

[0011]

Next, as in the invention of claim 4, an opening is formed in the reflecting mirror for passing the non-light emitting portion of the discharge lamp, and cooling air passing through this opening cools the non-light emitting portion of the discharge lamp. The non-light emitting portion of the discharge lamp is covered with a wind shield member for cooling air, and further, as in the invention of claim 5, the wind shield member is provided for cooling the metal foil embedded in the seal portion of the discharge lamp. When the opening is provided, the non-light emitting portion of the discharge lamp can be cooled to the optimum temperature.

According to the inventions of claims 3 and 6,
When a plurality of the photo-curing devices according to claim 1 to 4 are arranged in the traveling direction of the optical fiber to form a system,
The height direction of the entire system does not increase, and it is possible to support the drawing speed of the optical fiber from low speed to high speed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. 1 and 2 schematically show an embodiment of a photo-curing device of the present invention, in which a casing 1 is divided into two parts, one of which is a cooling air inlet 11
Is formed, and the discharge port 12 is formed on the other side. The reflecting mirror 2 which is also divided into two is arranged in the casing 1. The reflecting mirror 2 is an elongated elliptic cylinder whose inner surface is a mirror surface, and its focal axis is oriented in the vertical direction. Further, the reflecting mirror 2 is provided with a plurality of cooling air passage holes 21. Here, the height of the casing 1 is about 280.
mm.

The long arc type discharge lamp 3 is a reflecting mirror 2.
Although disposed inside, the linear light emitting portion of the discharge lamp 3 is located on the first focal axis of the reflecting mirror 2. On the other hand, the optical fiber F whose surface is coated with a coating agent made of an ultraviolet curable resin travels on the second focal axis of the reflecting mirror 2 from above to below. The optical fiber F is a quartz tube 7 in which oxygen gas has flowed inside and is in an oxygen poor state.
Is covered with. This is because when the coating agent is cured with light including ultraviolet rays, the curing reaction does not easily proceed in the presence of oxygen.

As described above, since the light emitting portion of the discharge lamp 3 is located on the first focal axis of the reflecting mirror 2 and the optical fiber F runs on the second focal axis of the reflecting mirror 2, the discharge lamp 3 emits light. Light including ultraviolet rays is condensed on the optical fiber F to cure the coating agent applied on the surface. At this time, the cooling air that has flowed in through the suction port 11 passes through the passage hole 21 of the reflecting mirror 2.
Through which the discharge lamp 3 is cooled, and the discharge lamp 3 is discharged through the passage hole 21 and the discharge port 12 of the other reflecting mirror 2.

The discharge lamp 3 is a metal halide lamp having a rated power consumption of 7 kW, and as shown in FIG. 3, a pair of electrodes 34, 34 are arranged inside the arc tube 31 so as to face each other. Further, the arc tube 31 is filled with a gas containing one or more metals. Therefore, the electrodes 34, 3
The light emitting portion L is between the tips of 4 and the length of the light emitting portion L is 250
mm.

Here, unlike the ordinary discharge lamp, the arc tube 31 has its tube ends 32 bent substantially at right angles. That is, both pipe end portions 32, 32 are bent in the same direction on the same plane. Therefore, the electrodes 34,
34 also has a distal end bent in an L shape. A molybdenum foil 35 is embedded in the seal portion 33 following the tube end portion 32, and one end of the electrode 34 is welded to the molybdenum foil 35. A base 36 is attached to the seal portion 33, and a lead wire 37 electrically connected to the molybdenum foil 35 extends from the end surface of the base 36. It should be noted that a discharge lamp in which the tube ends 32, 32 are bent in different directions and the overall shape is a crank shape may be used due to the relationship of lamp mounting and wiring.

As described above, since the tube ends 32 are bent substantially at right angles, the outer surface 36a of the base 36 becomes the end of the discharge lamp 3, and the total length of the discharge lamp 3 is about 270.
mm. A portion between the tip of the electrode 34 and the outer surface 36a of the base 36 is a non-light emitting portion N in the axial direction of the light emitting portion L, and the length of the non light emitting portion N is about 10 mm. That is, the length of the non-light emitting portion N is extremely shorter than that of a normal discharge lamp, and the ratio of the light emitting portion to the entire lamp length is about 93%. Therefore, in the photocuring device incorporating such a discharge lamp 3, the height of the casing 1 can be set to about 280 mm, and the ratio of the light emitting portion of the discharge lamp to the entire length of the device can be set to 90%.

In the conventional photo-curing device, since the discharge lamp is rod-shaped, the axis of the base at both ends coincides with the axis of the light emitting portion. Therefore, by holding this base, it was possible to fix the light emitting unit so as to be located on the focal axis of the reflecting mirror. Further, when the discharge lamp is turned on, the arc tube thermally expands, but the arc tube expands on the focal axis of the reflecting mirror. Therefore, even if the arc tube expands, the light emitting portion does not deviate from the focal axis of the reflecting mirror.

However, in the photocuring device of the present invention,
In the discharge lamp 3, since the tube ends 32 and 32 are bent substantially at right angles to the light emitting part L, if the bases 36 and 36 are held, the tube end 32 and the seal part 33 will also be reflective mirrors at the time of lighting. Since it expands in the direction perpendicular to the focal axis of the reflector, the light emitting portion deviates from the focal axis of the reflecting mirror. Further, it is difficult to bend the tube ends 32, 32 at a right angle to the light emitting part L on the same plane, and the bending angle varies. Therefore, if the discharge lamp is fixed while holding the bases 36, 36, the position of the light emitting portion between the electrodes 34, 34 does not completely coincide with the focal axis of the reflecting mirror.

Therefore, in the photocuring device of the present invention,
As shown in FIGS. 1 and 4, an opening 22 is provided in the inner bottom portion 2a of the reflecting mirror 2 and a tube end portion 32 of the discharge lamp 3 is inserted therein.
Then, a plurality of supporting members 4 made of quartz glass and having a V-shaped recess 41 are arranged on the bottom 2a of the reflecting mirror 2, and the arc tube 31 of the discharge lamp 3 is supported in a state of being fitted into the recess 41. It is brought into contact with the member 4 so that the light emitting portion between the electrodes 34 and 34 is located on the first focal axis of the reflecting mirror 2. The holding member 5 is attached to the base 36. That is, the holding portion 51 of the holding member 5 holds the base 36, and the holding portion 52 is brought into contact with the upper end surface of the base 36. Then, the elastic member 6 composed of a coil spring is arranged between the holding member 5 and the holding piece 13 of the casing 1, and the arc tube 31 is pressed against the support member 4 by the elastic force of the elastic member 6.

With such a lamp holding structure, even if the tube end portion 32 and the seal portion 33 expand in the direction perpendicular to the focal axis of the reflecting mirror at the time of lighting, the expansion is absorbed by the elastic member 6, so that the discharge lamp 3 Does not deviate from the focal axis of the reflecting mirror 2. Even if the bending angle of the pipe end portion 32 is not uniform and the pipe end portion 32 is not bent at a right angle on the same plane, the positioning is performed by the support member 4,
The light emitting portion of the discharge lamp 3 can be located on the focal axis of the reflecting mirror 2.

The opening 22 into which the tube end portion 32 of the discharge lamp 3 is inserted has an inner diameter larger than the outer diameter of the end portion 32 to form a gap. Then, the cooling air passes through the gap to cool the seal portion 33 and the pipe end portion 32. However, when the pipe end portion 32 is overcooled due to a large amount of air, it is preferable to cover the pipe end portion 32 with the tubular wind shield member 8 as shown in FIG. When the tube end portion 32 is supercooled, the enclosed metal gas condenses at the tube end portion 32 and the lamp performance deteriorates.

However, it is preferable that the seal portion 33 in which the molybdenum foil 35 is embedded is sufficiently cooled to prevent the molybdenum foil 35 from being oxidized, and therefore, the wind shield member 8 is cooled to cool the seal portion 33. It is preferable to provide the opening 81. That is, by appropriately determining the size of the wind shield member 8 and the number and position of the openings 81, the seal portion 33 and the pipe end portion 32 are
Can be adjusted so that each is cooled to the optimum temperature.

An example of using such a photo-curing device as a system is shown in FIG. The fiber material is melted in the fiber material melting furnace, and the optical fiber is drawn from the nozzle. This drawing speed is as high as several 100 m / min. A coating agent applying device is arranged under the nozzle, and a coating agent made of an ultraviolet curable resin is applied to the surface of the optical fiber. A plurality of photo-curing devices, for example, four photo-curing devices are stacked under the coating agent applying device. Here, since the ratio of the light emitting portion of the discharge lamp to the height of each photocuring device is large, the height direction of the entire system does not increase, and it is possible to operate even in a building with a low ceiling. Then, as described above, the coating agent applied to the surface of the optical fiber is cured by these photocuring devices, and is wound by the winding hobbin. In addition, another coating agent applying device and a plurality of photocuring devices may be arranged under the photocuring device to perform multi-layer coating.

Here, when the optical fiber is drawn at a high speed and a constant speed, the discharge lamps of all the photo-curing devices are turned on at full power (rated power), which is sufficient even for a high drawing speed. It is possible to secure a long exposure time. However, when the drawing speed at the start-up is slow, the discharge lamps of some devices are turned off, and as the drawing speed becomes faster, the ultraviolet ray output from the discharge lamp is changed from low output to high output. , The input power of the discharge lamp is adjusted, and the discharge lamp is sequentially turned on. When the drawing speed becomes slow, the input power of the discharge lamp is adjusted so that the ultraviolet light output from the discharge lamp is changed from high output to low output, and the drawing speed is changed by sequentially turning off the light. However, the exposure time can be made almost constant.

[0028]

As described above, the present invention uses the discharge lamp in which the non-light-emitting portion on the end side of the electrode tip is bent substantially at right angles to the light-emitting portion between the electrodes. The ratio of the light emitting portion of the discharge lamp to the ratio becomes large, and even if a plurality of light emitting units are stacked to form a photo-curing system, the photo-curing device in which the height direction of the entire system does not increase can be obtained. Even though the non-light emitting part of the discharge lamp is bent, the light emitting part of the discharge lamp should be accurately positioned on the focal axis of the reflecting mirror, and the non-light emitting part of the discharge lamp should be adjusted to the optimum temperature. It is possible to use a photocuring device capable of

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram of a discharge lamp.

FIG. 4 is a perspective view of a main part of the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a light curing system.

[Explanation of symbols]

1 casing 11 suction port 12 outlet 2 reflector 21 Cooling air passage hole 22 opening 2a The bottom of the reflector 3 discharge lamp 31 arc tube 32 pipe end 33 Seal part 34 electrodes 35 molybdenum foil 36 base 37 lead wire L light emitting part N Non-light emitting part 4 Support members 41 recess 5 holding member 51 Holding section 52 Holding part 6 elastic members 7 Quartz tube 8 Wind shield 81 Opening of wind shield F optical fiber

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 6/44 301 B05C 9/12 C03C 25/02

Claims (6)

(57) [Claims] 1. An elliptic cylindrical reflecting mirror whose inner surface is a mirror surface,
A pair of electrodes are arranged inside the arc tube so as to face each other, and a light emitting portion between the electrodes is a discharge lamp positioned on the first focal axis of the reflecting mirror. In a photo-curing device for curing a coating agent applied to a surface of an optical fiber traveling on a second focal axis, the discharge lamp has a non-light emitting portion on an end side of an electrode tip with respect to a light emitting portion between both electrodes. A support member having a V-shaped concave portion is arranged on the inner surface of the reflecting mirror, bent substantially at a right angle, and the outer surface of the arc tube of the discharge lamp is positioned so as to be inscribed in the concave portion of the support member. The photo-curing device, wherein the arc tube of the lamp is pressed into contact with the recess of the supporting member by an elastic member arranged on the back of the reflecting mirror. 2. The photocuring device according to claim 1, wherein the non-light emitting portions at both ends of the discharge lamp are bent in the same direction on the same plane. 3. A photocuring system comprising a plurality of the photocuring devices according to claim 1 arranged in a traveling direction of an optical fiber. 4. An elliptic cylindrical reflecting mirror whose inner surface is a mirror surface,
A pair of electrodes are arranged inside the arc tube so as to face each other, and a light emitting portion between the electrodes is a discharge lamp positioned on the first focal axis of the reflecting mirror. In a photo-curing device for curing a coating agent applied to a surface of an optical fiber traveling on a second focal axis, the discharge lamp has a non-light emitting portion on an end side of an electrode tip with respect to a light emitting portion between both electrodes. The reflector is bent at a substantially right angle, and an opening through which the non-light emitting portion of the discharge lamp passes is formed in the reflecting mirror, and the cooling air passing through the opening cools the non-light emitting portion of the discharge lamp. The photocuring device is characterized in that the portion is covered with a wind shielding member against cooling air. 5. The photo-curing device according to claim 4, wherein the wind shield member is provided with an opening for cooling the metal foil embedded in the seal portion of the discharge lamp. 6. A photo-curing system comprising a plurality of the photo-curing devices according to claim 4 arranged in the traveling direction of an optical fiber.