Gas purging device and ultraviolet irradiation device

Abstract

To provide a gas purging apparatus forming a gas purge chamber of an inert gas atmosphere on a transportation path of a workpiece, the apparatus capable of preventing an inflow of air into or an outflow of the inert gas from the gas purge chamber without increasing the size of the whole apparatus.SOLUTION: A gas purging apparatus is used for an ultraviolet light radiation apparatus configured to irradiate a workpiece moving in a prescribed transportation direction with ultraviolet light, and for forming an inert gas atmosphere on a transportation path of the workpiece. The gas purging apparatus includes: a gas purge chamber disposed on the transportation path and to be packed with an inert gas; an opening configured to guide the workpiece in and out; a casing configured to form a window part to bring the ultraviolet light into the gas purge chamber; a labyrinth structure disposed at the opening and configured to apply a resistance to a gas flowing in the opening; and a gas suction part disposed outside the labyrinth structure when viewed from the gas purge chamber and configured to suck in the gas outside the gas purge chamber. The labyrinth structure and the gas suction part are integrally formed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a gas purge device and an ultraviolet irradiation device used for ultraviolet curing treatment and the like.

Background Art

[0002] For example, when performing ultraviolet curing treatment on resins, paints, inks, adhesives, etc., a gas purge device is used to suppress the inhibition of the photo radical polymerization reaction by oxygen (oxygen inhibition). This gas purge device forms a gas purge chamber filled with an inert gas. By placing a workpiece in this gas purge chamber and performing ultraviolet irradiation, the influence of oxygen inhibition can be suppressed and the curing quality can be improved.

[0003] As this type of gas purge device, for example, as shown in Patent Document 1, there is one that is provided on the conveyance path of a workpiece such as a film conveyed in a predetermined direction, and is configured such that the workpiece is continuously introduced and discharged from an opening provided in the gas purge chamber. This type of gas purge device has a problem that external air containing oxygen flows into the gas purge chamber through the opening, so it is easily affected by oxygen inhibition. Also, the inert gas in the gas purge chamber may flow out to the outside through the opening, which may lead to a large consumption of the inert gas. Therefore, in Patent Document 1, a labyrinth structure is provided at the opening to reduce the inflow and outflow of gas through the opening. Also, in this Patent Document 1, an exhaust structure is provided outside the labyrinth structure to suck in and recover the inert gas flowing out from the gas purge chamber.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In gas purging systems applied to transported workpieces as described above, further reduction of gas inflow and outflow through openings is required to further reduce the impact of oxygen inhibition on UV curing and to further reduce the consumption of inert gas. However, adding new equipment configurations to reduce gas inflow and outflow would lead to an increase in the size of the gas purging system.

[0006] This invention has been made in view of the above problems, and its main objective is to suppress the inflow of air into the gas purge chamber and the outflow of inert gas in a gas purge device that forms a gas purge chamber with an inert gas atmosphere on the transport path of a workpiece, without increasing the overall size of the device. [Means for solving the problem]

[0007] In other words, the gas purging device according to the present invention is used in an ultraviolet irradiation device that irradiates ultraviolet light onto a workpiece moving along a predetermined transport direction, and is for forming an inert gas atmosphere on the transport path of the workpiece, and comprises a casing that is provided on the transport path and filled with inert gas, an opening for bringing the workpiece out or into the casing and a window for taking ultraviolet light into the gas purging chamber, a labyrinth structure provided in the opening to apply resistance to the gas flowing through the opening, and a gas intake section provided outside the labyrinth structure as viewed from the gas purging chamber and for drawing in gas from outside the gas purging chamber, wherein the labyrinth structure and the gas intake section are integrally provided.

[0008] Furthermore, the ultraviolet irradiation device of the present invention is characterized by comprising the gas purging device and an ultraviolet irradiator that irradiates ultraviolet light into the gas purging chamber through the window. [Effects of the Invention]

[0009] According to the present invention configured in this way, in a gas purging device that forms a gas purging chamber with an inert gas atmosphere on the workpiece transport path, it is possible to suppress the inflow of air into the gas purging chamber and the outflow of inert gas without increasing the overall size of the device. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram showing the overall configuration of a system including an ultraviolet irradiation device according to one embodiment of the present invention. [Figure 2] A schematic diagram showing the overall configuration of the ultraviolet irradiation device according to this embodiment. [Figure 3] This figure shows the configuration near the introduction-side opening of the ultraviolet irradiation device in the same embodiment. [Figure 4] This figure shows the configuration of the sealing member of the ultraviolet irradiation device according to the same embodiment. [Figure 5] A schematic diagram showing the overall configuration of a system including an ultraviolet irradiation device of another embodiment. [Figure 6] A schematic diagram showing the overall configuration of an ultraviolet irradiation device in another embodiment. [Figure 7] A diagram showing the configuration of a sealing member in another embodiment of an ultraviolet irradiation device. [Figure 8] This figure shows the configuration near the introduction-side opening of an ultraviolet irradiation device in another embodiment. [Modes for carrying out the invention]

[0011] An ultraviolet irradiation device 300 equipped with a gas purging device 100 according to one embodiment of the present invention will be described below with reference to the drawings.

[0012] The ultraviolet irradiation device 300 of this embodiment is for irradiating a film-like workpiece W, which is transported in a predetermined direction by a transport mechanism C, with ultraviolet light. As shown in Figure 1, this transport mechanism C is a so-called roll-to-roll type equipped with a plurality of transport rollers R, such as an unwinding roller and a winding roller, and the ultraviolet irradiation device 300 is used by being positioned on the transport path between two transport rollers R. The workpiece W is, for example, made by coating a substrate such as paper or film with paint, adhesive, ink, etc. In the following, the direction in which the workpiece W is transported is also called the transport direction, the direction perpendicular to the irradiated surface of the workpiece W is also called the height direction, and the direction perpendicular to both the transport direction and the height direction is also called the width direction.

[0013] Specifically, as shown in Figure 2, the ultraviolet irradiation device 300 comprises a gas purging device 100 that forms a gas purging chamber 1s with an inert gas atmosphere on the transport path of the workpiece W, and an ultraviolet irradiator 200 that irradiates ultraviolet light into the gas purging chamber 1s.

[0014] Specifically, the gas purging device 100 comprises a casing 1 that forms a gas purging chamber 1s, an opening 1a, and a window section 1w; an inert gas supply mechanism 2 that supplies inert gas into the casing 1; a labyrinth structure 3 provided in the opening 1a of the casing 1; and an exhaust mechanism 4 provided on the outside of the labyrinth structure 3 as viewed from the gas purging chamber 1s.

[0015] The casing 1 is provided on the transport path between a pair of transport rollers R and is configured to cover the workpiece W from both sides in the height direction (the side to be irradiated and the back side). The casing 1 is box-shaped and has a gas purge chamber 1s formed inside. The casing 1 in this embodiment comprises an upper casing 11 that covers the side to be irradiated of the workpiece W and a lower casing 12 that covers the back side of the workpiece W. The upper casing 11 and the lower casing 12 are arranged so that their openings face each other, and the gas purge chamber 1s is formed by the opposing inner wall surfaces of each. The ends of the gas purge chamber 1s along the width direction are closed by side plates of the casing 1 (not shown).

[0016] At both ends of the gas purge chamber 1s along the conveying direction, a pair of openings 1a (an introduction side opening 1a1 and a discharge side opening 1a2) for introducing and discharging the work W are formed. One end of this opening 1a along the conveying direction opens to the gas purge chamber 1s, and the other end opens to the outside of the gas purge chamber 1s (that is, the air atmosphere). The work W continuously conveyed from the upstream side is introduced into the gas purge chamber 1s through the introduction side opening 1a1, passes through the gas purge chamber 1s, and is discharged from the discharge side opening 1a2 and conveyed to the downstream side.

[0017] On the upper wall 11a of the casing 1 forming the gas purge chamber 1s, a window portion 1w for taking ultraviolet rays into the gas purge chamber 1s is formed. This window portion 1w includes an opening formed in a rectangular shape in plan view formed on the upper wall 11a and a plate member covering this opening. This plate member is made of a material that transmits ultraviolet rays, such as quartz glass.

[0018] The inert gas supply mechanism 2 supplies an inert gas such as N2 gas into the gas purge chamber 1s. This inert gas supply mechanism 2 includes a gas supply source (not shown) provided outside the gas purge chamber 1s and a gas supply pipe 21 connected to the gas supply source and supplying the inert gas into the gas purge chamber 1s through one or more inert gas supply ports 2a provided in the gas purge chamber 1s. The gas supply pipe 21 has a straight pipe portion extending along the width direction in the gas purge chamber 1s, and the inert gas supply port 2a is formed by a through hole penetrating the pipe wall of this straight pipe portion. In this embodiment, the inert gas supply port 2a is provided so as to supply the inert gas to the irradiated surface side of the work W (that is, between the work W and the upper wall 11a) in the vicinity of the opening 1a in the gas purge chamber 1s. By supplying the inert gas from the inert gas supply port 2a, the inside of the gas purge chamber 1s becomes a positive pressure inert gas atmosphere.

[0019] The labyrinth structure 3 suppresses the outflow of the inert gas from the gas purge chamber 1s and the inflow of air into the gas purge chamber 1s by applying resistance to the gas flowing through (passing through) the opening 1a. This labyrinth structure 3 is provided at each of the introduction-side opening 1a1 and the lead-out-side opening 1a2 of the casing 1. Further, in the gas purge device 100 of the present embodiment, the labyrinth structure 3 is provided on both the irradiated surface side and the back surface side of the work W at each opening 1a.

[0020] Specifically, as shown in FIGS. 3 and 4, this labyrinth structure 3 is composed of a plurality of protruding portions 31 and a plurality of grooves 32 arranged alternately along the conveyance direction. The protruding portion 31 functions as a throttle portion that narrows the gas flow path at the opening 1a, and protrudes toward the surface of the work W along the height direction to form a convex shape. The plurality of protruding portions 31 are arranged side by side along the conveyance direction. The groove 32 functions as an expansion chamber that widens the gas flow path at the opening 1a, and is formed between the protruding portions 31 so as to form a concave shape that recedes from the surface of the work W along the height direction. Both the protruding portion 31 and the groove 32 are formed in an elongated shape extending along the width direction. Each protruding portion 31 constituting the labyrinth structure 3 is formed such that the heights of the tip surfaces from the surface of the work W are aligned (substantially the same).

[0021] More specifically, this labyrinth structure 3 is formed in a block-shaped seal member 3m made of, for example, a metal material, which is arranged with a gap from the surface of the work W at the opening 1a. This seal member 3m has a facing surface facing the surface of the work W, and a plurality of protruding portions 31 and grooves 32 are formed on this facing surface. The seal member 3m of the present embodiment is configured to be able to vary its position along the height direction, whereby the gap dimension between the surface of the work W and the labyrinth structure 3 can be adjusted.

[0022] The exhaust mechanism 4 draws in and exhausts air from outside the gas purge chamber 1s that flows into the opening 1a, and inert gas that flows out to the outside from the opening 1a. Specifically, this exhaust mechanism 4 comprises a gas intake section 41 provided adjacent to the outside of the labyrinth structure 3, and an exhaust duct 42 that exhausts the gas drawn in by the gas intake section 41. In this embodiment, the gas intake section 41 is provided corresponding to each of the multiple labyrinth structures 3 provided at each opening 1a of the casing 1. The exhaust duct 42 is connected to an exhaust fan (not shown) provided on the downstream side.

[0023] As shown in Figures 3 and 4, the gas intake section 41 is integrally provided with the labyrinth structure 3. Specifically, the gas intake section 41 has a plate-shaped extension member 411 that extends further outward along the transport direction from the outermost protrusion (referred to as the outer protrusion) 311 of the labyrinth structure 3, and a plurality of intake holes 41h that penetrate the extension member 411 in the thickness direction. This extension member 411 is formed from a single component that is integrated with the sealing member 3m, which includes the outer protrusion 311, and thus the gas intake section 41 and the labyrinth structure 3 form an integrated structure composed of common components.

[0024] The intake hole 41h opens onto the opposing surface 411s of the extension member 411 that faces the surface of the workpiece W, and this opening functions as an intake port for drawing in gas. The opposing surface 411s of the extension member 411 is formed such that its height from the surface of the workpiece W is the same as (approximately identical to) the height from the surface of the workpiece W of the tip of the projection 31 of the labyrinth structure 3. In other words, the height of the opening end of the intake hole 41h on the workpiece W side is approximately the same as the height of the tip of the projection 31 of the labyrinth structure 3.

[0025] Each intake hole 41h has an elongated shape that extends along the width direction. Multiple intake holes 41h are arranged at intervals along the width direction and in multiple rows (three rows in this case) at intervals along the conveying direction. When viewed from the height direction, these multiple intake holes 41h may be formed in a staggered pattern along the conveying direction, or in a grid pattern aligned along the conveying direction.

[0026] The gas purging device 100 also includes an oxygen concentration measuring mechanism (not shown) for measuring the oxygen concentration in the gas purging chamber 1s. This oxygen concentration measuring mechanism includes an oxygen concentration meter located outside the gas purging chamber 1s and a gas suction pipe whose downstream end is connected to the oxygen concentration meter and which draws in gas from one or more measuring gas suction ports located inside the gas purging chamber 1s.

[0027] Furthermore, the gas purging device 100 is further equipped with a heat sink 6 attached to the casing 1. This heat sink 6 promotes heat dissipation from the casing 1, which heats up when irradiated with ultraviolet light. The heat sink 6 is provided in the region of the inner wall surface of the casing 1 that faces the window portion 1w. Specifically, this heat sink 6 is composed of a plurality of flat heat dissipation fins 61. These plurality of heat dissipation fins 61 stand perpendicular to the inner wall surface of the casing 1, and are provided so that the main heat dissipation surface with a large surface area is substantially parallel to the transport direction.

[0028] The ultraviolet irradiator 200 is constructed using an ultraviolet light source such as a UV-LED, and is a surface-type irradiator that emits ultraviolet light from a rectangular light-emitting surface, for example. The ultraviolet irradiator 200 is mounted on a mounting part provided on the casing 1 of the gas purging device 100, such that its light-emitting surface faces the window portion 1w of the gas purging device 100.

[0029] With the gas purging device 100 and ultraviolet irradiation device 300 using the same configured in this embodiment, the gas intake section 41 provided on the outside of the opening 1a is integrally provided with the labyrinth structure 3. Therefore, the gas intake section 41 itself can function as if it were a second labyrinth structure extending to the outside of the labyrinth structure 3. In other words, the intake port of the gas intake section 41 can function as an expansion chamber that widens the gas flow path, thereby suppressing the inflow of air into the gas purging chamber 1s and the outflow of inert gas. Moreover, since the structure of the existing gas intake section 41 can be utilized rather than adding a new device configuration, the overall size of the device can be kept down.

[0030] Furthermore, since the intake holes 41h of the gas intake section 41 are arranged at intervals along the conveying direction, regions where the flow path widens and regions where it narrows alternate along the conveying direction, thereby further enhancing the labyrinth effect of the gas intake section 41.

[0031] <Other Embodiments> However, the present invention is not limited to the embodiments described above.

[0032] For example, the ultraviolet irradiation device 300 and gas purging device 100 in the above embodiment were installed and used between the two transport rollers R of the transport mechanism C, but are not limited to this. The ultraviolet irradiation device 300 and gas purging device 100 in other embodiments may be used by being attached to the transport rollers R, as shown in Figures 5 to 7, and irradiate the surface of the workpiece W that is wound (or unwound) on the circumferential surface of the transport rollers R with ultraviolet light.

[0033] As shown in Figure 6, the casing 1 of this embodiment has an open bottom surface facing the circumferential surface of the conveyor roller R, and its inner wall surface is positioned to cover a portion of the circumferential surface of the conveyor roller R. The inner wall surface of the casing 1 and the circumferential surface of the conveyor roller covered by it form a gas purge chamber 1s. Both ends of the gas purge chamber 1s along the width direction are closed by side plates of the casing 1 (not shown).

[0034] In this embodiment, the opposing surface of the sealing member 3m has a curved shape that follows the circumferential surface of the conveying roller R, and the labyrinth structure 3 is formed by a plurality of protrusions 31 and a plurality of grooves 32 that are alternately formed on the opposing surface in the conveying direction (the direction of rotation of the roller). The opposing surface 411s of the extension member 411 also has a curved shape that follows the circumferential surface of the conveying roller R, and a plurality of intake holes 41h are formed so as to open into this opposing surface 411s. In this embodiment as well, as shown in Figure 7, the plurality of intake holes 41h are arranged in multiples with spacing along the width direction and in multiple rows (in this case, 3 rows) with spacing along the conveying direction.

[0035] Even with the gas purging device 100 configured in this way, as shown in Figures 5 to 7, the effects of the present invention described above can be achieved.

[0036] Furthermore, in each of the above embodiments, the gas intake section 41 and the labyrinth structure 3 formed an integrated structure made of a common material, but this is not limited to this. In other embodiments, the gas intake section 41 and the labyrinth structure 3 may be separate structures made of independent materials, as long as they are provided in close proximity and integrally.

[0037] Furthermore, in each of the above embodiments, the opposing surface 411s of the extension member 411 were formed to be at the same height as the tip of the protruding portion 31 of the labyrinth structure 3, but this is not limited to this. For example, as shown in Figure 8, the opposing surface 411s of the extension member 411 may be formed at a position set back in the height direction from the tip of the protruding portion 31 of the labyrinth structure 3. In this case, a second protruding portion 412 may be provided at the outer end of the extension member 411 along the conveying direction, projecting toward the surface of the workpiece W along the height direction. This second protruding portion is a long plate-shaped member extending along the width direction, and is configured such that the height of its tip is at the same height as the tip of the outer rib 311.

[0038] In each of the above embodiments, the intake hole 41h had an elongated shape, but it is not limited to this. In other embodiments, the intake hole 41h may have any shape, such as a round hole or a square hole.

[0039] Furthermore, although the intake holes 41h were provided in multiple locations along the width direction in each of the above embodiments, this is not limited to this. If the intake holes 41h have a shape that extends along the width direction, they do not need to be provided in multiple locations along the width direction. In yet another embodiment, the intake holes 41h do not need to be arranged in multiple locations along the conveying direction.

[0040] Furthermore, in the above embodiment, the inert gas supply port 2a was provided to supply inert gas only to the side of the workpiece W that is irradiated, near the opening 1a in the gas purge chamber 1s, but it is not limited to this. In other embodiments, the inert gas supply port 2a may be provided to supply inert gas to the back side of the workpiece W as well, near the opening 1a in the gas purge chamber 1s.

[0041] In other embodiments, the window portion 1w does not include a plate member to cover the opening formed in the upper wall 11a, and may consist only of the opening. In this case, it is preferable to configure the opening constituting the window portion 1w to be airtightly sealed with the light-emitting surface of the ultraviolet irradiator 200 or the like.

[0042] Furthermore, in other embodiments, the workpiece W may not be in the form of a film, but may be in any shape, such as a sheet or a plate.

[0043] Furthermore, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from its spirit.

[0044] <Modes of gas purging devices and ultraviolet irradiation devices included in this specification> Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0045] (Aspect 1) A gas purging device used in an ultraviolet irradiation device that irradiates ultraviolet light onto a workpiece moving along a predetermined transport direction, for forming an inert gas atmosphere on the transport path of the workpiece, comprising: a casing provided on the transport path and filled with an inert gas, an opening for bringing the workpiece out or into the casing and a window for taking ultraviolet light into the gas purging chamber, a labyrinth structure provided in the opening to apply resistance to the gas flowing through the opening, and a gas intake section provided outside the labyrinth structure as viewed from the gas purging chamber and for drawing in gas from outside the gas purging chamber, wherein the labyrinth structure and the gas intake section are integrally provided.

[0046] With this design, the gas intake section located outside the opening is integrated with the labyrinth structure, allowing the gas intake section itself to function as a second labyrinth structure extending outside the labyrinth structure. In other words, the gas intake section can function as an expansion chamber that widens the gas flow path, thereby suppressing the inflow of air into the gas purging chamber and the outflow of inert gas. Moreover, since it utilizes the existing gas intake section structure rather than adding a new device configuration, the overall size of the device can be kept down.

[0047] (Aspect 2) The gas purging device according to aspect 1, wherein the gas intake section has a plurality of intake holes arranged along the transport direction. With this design, the intake holes in the gas intake section are arranged at intervals along the conveying direction, so that areas where the flow path widens and areas where it narrows alternate along the conveying direction, further enhancing the labyrinth effect of the gas intake section.

[0048] (Aspect 3) The gas purging device according to aspect 2, wherein the labyrinth structure is composed of a plurality of protrusions that project toward the surface of the workpiece and are arranged in line along the conveying direction, and grooves formed between the plurality of protrusions, and the plurality of intake holes are formed in an extension member that extends further outward from the outermost protrusion in the labyrinth structure along the conveying direction. With this configuration, a gas intake section having multiple intake holes can be integrated with the labyrinth structure.

[0049] (Aspect 4) The gas purging device according to aspect 3, wherein the plurality of intake holes open to the opposing surface of the extension member that faces the surface of the workpiece, and the height of the opposing surface from the surface of the workpiece is substantially the same as the height of the tip of the projection of the labyrinth structure from the surface of the workpiece. With this configuration, the gap between the opposing surface of the extension member and the workpiece surface can be reduced, further decreasing the inflow of air into the opening and the outflow of inert gas.

[0050] (Aspect 5) The gas purging device according to any one of aspects 2 to 4, wherein the intake hole has an elongated shape that extends in a direction perpendicular to the conveying direction. In this way, by making the intake port elongated in the width direction, a labyrinth effect can be achieved across the width direction.

[0051] (Aspect 6) A gas purging device according to any one of aspects 2 to 5, wherein the intake holes are arranged in each row at intervals in a direction intersecting the workpiece transport direction. In this way, the areas where the flow path widens and the areas where the flow path narrows can be further increased, allowing the labyrinth effect to be more strongly exerted in the gas intake section.

[0052] (Aspect 7) A gas purging device according to any one of aspects 1 to 6, wherein the labyrinth structure and the gas intake section are made of a common material and form an integrated structure. By integrating the labyrinth structure and the gas intake section into a single unit, space can be further reduced, resulting in a more compact device configuration.

[0053] (Aspect 8) A gas purging device according to any one of aspects 1 to 7, wherein a plurality of plate-shaped heat dissipation fins are provided in a region of the inner wall surface of the casing facing the window portion, so as to be substantially parallel to the transport direction. In this configuration, multiple plate-shaped heat dissipation fins are provided in the area facing the window. This allows ultraviolet light that is irradiated onto the inner wall surface of the casing and reflected without being absorbed (i.e., without being converted into thermal energy) to be irradiated onto the surface of the heat dissipation fins and absorbed. This reduces unwanted ultraviolet light that is reflected from the inner wall surface of the casing and irradiated onto the back surface of the workpiece. Furthermore, by providing the heat dissipation fins in the area that is most likely to become hot when ultraviolet light is irradiated into the gas purging chamber, the casing can be cooled effectively. Moreover, by arranging multiple heat dissipation fins approximately parallel to each other along the conveying direction, gas can flow efficiently between the multiple heat dissipation fins, enabling efficient heat dissipation.

[0054] (Aspect 9) An ultraviolet irradiation device comprising a gas purging device according to any one of aspects 1 to 8 and an ultraviolet irradiator that irradiates ultraviolet light into the gas purging chamber through the window. Such an ultraviolet irradiation device can achieve the same effects as the gas purging device described above. [Explanation of Symbols]

[0055] 300...UV irradiation device 100... Gas purging device 1. Casing 1s ···Gas purging room 1a...opening 1w ···Window section 3. Labyrinth structure 4. Exhaust mechanism 41...Gas intake section 41h... Intake vent 200...UV irradiator W ···Work C ··· Conveying device R ··· Conveyor roller

Claims

1. This device is used in an ultraviolet irradiation device that irradiates ultraviolet light onto a workpiece moving along a predetermined transport direction, and is used to form an inert gas atmosphere on the transport path of the workpiece. A casing provided on the transport path, comprising a gas purge chamber filled with inert gas, an opening for bringing the workpiece out or into the casing, and a window for bringing ultraviolet light into the gas purge chamber, A labyrinth structure is provided in the opening and applies resistance to the gas flowing through the opening, The system includes a gas intake section for drawing in gas from outside the gas purging chamber, which is integrally provided with the labyrinth structure on the outside of the labyrinth structure as viewed from the gas purging chamber, A gas purging device having a second labyrinth structure in the gas suction section that applies resistance to the gas flowing along the transport path.

2. The gas purging device according to claim 1, wherein the gas intake section has a plurality of intake holes arranged along the conveying direction.

3. The labyrinth structure is composed of a plurality of protrusions that project toward the surface of the workpiece and are arranged in line along the transport direction, and grooves formed between the plurality of protrusions. The gas purging device according to claim 2, wherein the plurality of intake holes are formed in an extension member provided so as to extend further outward along the transport direction from the outermost projection in the labyrinth structure.

4. The plurality of intake holes open to the opposing surface of the extension member that faces the surface of the workpiece, The gas purging device according to claim 3, wherein the height of the opposing surface from the surface of the workpiece and the height of the tip of the projection of the labyrinth structure from the surface of the workpiece are substantially the same.

5. The gas purging device according to claim 2, wherein the intake hole has an elongated shape that extends in a direction perpendicular to the conveying direction.

6. The gas purging device according to claim 2, wherein a plurality of intake holes are arranged in each row at intervals in a direction intersecting the workpiece transport direction.

7. The gas purging device according to claim 1, wherein the labyrinth structure and the gas intake section are made of a common material and form an integrated structure.

8. The gas purging device according to claim 1, wherein a plurality of plate-shaped heat dissipation fins are provided in a region of the inner wall surface of the casing facing the window portion, so as to be substantially parallel to the conveying direction.

9. A gas purging device according to any one of claims 1 to 8, An ultraviolet irradiation device comprising an ultraviolet irradiator that irradiates ultraviolet light into the gas purging chamber through the aforementioned window.

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