LIGHTING DEVICE

Abstract

A light illumination device for shining light onto a target object being transported along a first direction, the light illumination device comprising: a light source unit with a plurality of light-emitting diode (LED) components to shine light onto the target object from a second direction perpendicular to the first direction; and a light shielding unit positioned opposite the light source unit with an intermediate conveying passage for the target object to shield the light emitted by the light source unit in order to prevent escape; the light shielding unit includes: a light-absorbing element to absorb the light emitted by the light source unit; a housing to accommodate and hold at least part of the light-absorbing element; and a wind tunnel formed between the housing and the light-absorbing element to allow cooling air to flow.

Description

[Technical field]

[0001] The present disclosure relates to a light illumination device for radiating light onto a target object that is being transported. [Background of the technology]

[0002] Traditionally, printers are known to use UV ink, which is cured by UV light. These printers eject ink from a nozzle onto a printing medium and then shine UV light onto a dot that forms on the medium. This dot is cured by the UV light and deposited onto the medium, thus enabling high-quality printing even on media that are not typically absorbent.

[0003] In a UV light illumination device used in such printers, the use of a light-emitting diode (LED) component as an alternative to a conventional discharge lamp for a light source has recently been implemented in practice to meet the demand for reduced power consumption, long service life and compact size (e.g. patent literature 1).

[0004] The light illumination device disclosed in patent literature 1 has a workpiece placement space within a housing and emits UV light from a plurality of LED components onto a workpiece that passes through the workpiece placement space in order to cure UV-curing resin on the workpiece. RELATED LITERATURE Patent literature

[0005] Japanese Patent Publication No. 2018-118499 [Disclosure] [Technical problem]

[0006] According to the configuration described in patent literature 1, ultraviolet (UV) light is directed onto a workpiece passing through the workpiece placement chamber (i.e., a space within the housing), thus preventing UV light from escaping the workpiece placement chamber to some extent. However, since UV light is directed within the workpiece placement chamber, which is an enclosed space, it is reflected at various points, such as the housing within the workpiece placement chamber or the workpiece itself. Therefore, it is impossible to completely prevent UV light from escaping the workpiece placement chamber. When UV light comes into contact with the housing within the workpiece placement chamber, the housing generates heat, which prevents the UV light from making contact with the housing.

[0007] To address this problem, the present disclosure is directed to provide a light illumination device that completely prevents UV light from escaping from the light illumination device and that prevents heat generation from a housing. [Technical solution]

[0008] To solve the above problem, a light illumination device of the present disclosure is a light illumination device for radiating light onto a target object that is conveyed along a first direction, and comprises a light source unit with a plurality of light-emitting diode (LED) devices to radiate light onto the target object from a second direction perpendicular to the first direction; and a light shielding unit arranged opposite the light source unit with an intermediate conveying passage for the target object to shield the light radiated by the light source unit to prevent escape;wherein the light shielding unit comprises a light-absorbing element to absorb the light emitted by the light source unit, a housing to accommodate and hold at least part of the light-absorbing element, and a wind channel formed between the housing and the light-absorbing element to allow cooling air to flow.

[0009] According to this configuration, because the light shielding unit absorbs the light emitted by the light source unit through the light-absorbing element, it is possible to prevent ultraviolet (UV) light from escaping the lighting device. Furthermore, because cooling air flows between the housing and the light-absorbing element, it is possible to prevent heat generation by the light shielding unit.

[0010] Furthermore, the housing is preferably in the form of a box with an opening on the conveying side and has a first air inlet in at least part of the opening to introduce air from the outside into the wind tunnel. In this case, the housing also preferably has a second air inlet at one end in a third direction perpendicular to the first and second directions to introduce air from the outside into the wind tunnel.

[0011] Furthermore, the enclosure can be configured to have an exhaust fan at the other end of the third direction perpendicular to the first and second directions to expel air inside the wind tunnel to the outside.

[0012] Furthermore, the light-absorbing element is preferably in the form of a box with an opening on the conveying side and is attached to the housing at a predetermined distance from it. In this case, the light-absorbing element also preferably has a black, electroless nickel plating or chrome plating on an inner surface.

[0013] Furthermore, the light source unit and the light shielding unit are preferably connected at one end by a hinge.

[0014] Furthermore, the light emitted by the light source unit is predominantly UV light. [Beneficial effects]

[0015] As described above, according to the present disclosure it is possible to implement a light illumination device that completely prevents UV light from escaping from the light illumination device and that prevents heat generation from the housing. [Description of the drawings] Fig. 1A and Fig. Figure 1B are diagrams showing the configuration of a light illumination device according to an embodiment of the present disclosure. Fig. Figure 2 is a cross-sectional view along line BB of Fig. 1B. Fig. Figure 3 is a cross-sectional view along line AA of Fig. 1A. Fig. Figure 4 is a cross-sectional view along line CC of Fig. 1B. Fig. Figure 5 is an exploded or stretched perspective view of a light shielding unit provided in a light illumination device, according to an embodiment of the present disclosure. Fig. Figure 6 is a diagram showing a variation of a light illumination device according to an embodiment of the present disclosure. [Mode for the invention]

[0016] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Furthermore, the same reference numeral is used in the drawings for identical or equivalent parts, and its description is not repeated here.

[0017] The Fig. 1A and Fig. 1B are diagrams showing the configuration of a light illumination device 1 according to an embodiment of the present disclosure, Fig. 1A is a perspective view and Fig. 1B is a front view. Furthermore, Fig. 2 a cross-sectional view along line BB from Fig. 1B and Fig. Figure 3 is a cross-sectional view along line AA of Fig. 1A. As in the Fig. As shown in Figures 1 to 3, the light illumination device 1 is a device for curing ultraviolet (UV)-curing resin applied to the surface of a conveyed target object P (e.g., a receiving medium, etc.) and comprises a light source unit 10 arranged above the target object P and a light shielding unit 20 arranged opposite the light source unit 10 with an intermediate conveying passage 40 for the target object P. Furthermore, the description defines a longitudinal direction of the UV light along a line emitted by the light source unit 10 as the X-axis direction, a conveying direction of the target object P as the Y-axis direction, and a direction perpendicular to the X-axis and Y-axis as the Z-axis direction.

[0018] As in the Fig. 2 and Fig. As shown in Figure 3, the light source unit 10 emits UV light in a line along the X-axis direction and comprises a substrate 13, a plurality of light-emitting diode (LED) components 14 arranged on the substrate 13, a cooler 15 and a container 11 to hold them.

[0019] Container 11 is a metal box-shaped housing with an opening in a bottom surface (a lower surface in the Fig. 1 to 3) and a glass window 12 is inserted into the opening in the lower surface ( Fig. 2 and Fig. 3) Furthermore, a pair of light-shielding plates 17 are arranged on the bottom surface of the container 11 of this embodiment, with a window 12 positioned between them. Each light-shielding plate 17 is a rectangular, plate-shaped metal element defined in the X-axis and Y-axis directions and is attached to the container 11 such that each extends from the container 11 in the Y-axis direction and in a direction opposite to the Y-axis direction. The surface of each light-shielding plate 17 facing the light-shielding unit 20 (i.e., the surface of the Z-axis direction) has a black electroless nickel plating or chrome plating, and when UV light from the light source unit 10 is reflected away from the target object P, each light-shielding plate 17 thus absorbs the reflected light to prevent leakage from the light-illuminating device 1.

[0020] Substrate 13 is a rectangular wiring substrate made of a material with high thermal conductivity (e.g., aluminum nitride), defined in the X-axis and Y-axis directions. As shown in the Fig. 2 and Fig. As shown in Figure 3, the majority of the LED devices 14 are mounted on the surface of the substrate 13, for example, in an array of 150 (X-axis direction) × 4 (Y-axis direction) using a chip-on-board (COB) system. An anode pattern (not shown) and a cathode pattern (not shown) are formed on the substrate 13 to power each LED device 14, and each LED device 14 is electrically connected to every other LED device 14 in the anode and cathode patterns. The substrate 13 is also electrically connected to a driver circuit (not shown), with no wiring shown, to supply a drive current from the driver circuit to each LED device 14 through the anode and cathode patterns. When the drive power is supplied to each LED device 14, the amount of UV light corresponding to the drive current (e.g.,Wavelength 365 nm) is emitted by each LED component 14, and UV light is emitted in a line parallel to the X-axis direction by the light source unit 10. Furthermore, each LED component 14 of this embodiment is supplied with the controlled drive current to emit an approximately uniform amount of UV light, and the UV light emitted in a line by the light source unit 10 exhibits an approximately uniform light distribution in the X-axis direction.

[0021] The cooler 15 is a so-called air-cooled heat sink, which is arranged in close contact with the rear surface of the substrate 13 to dissipate the heat generated by each LED component 14. The cooler 15 comprises a plurality of heat dissipation fins 16 made of a material with good thermal conductivity, e.g., aluminum or copper, and a cooling fan (not shown), and the majority of the heat dissipation fins 16 are uniformly cooled by an airflow generated by the cooling fan.

[0022] When the light source unit 10 is supplied with power and UV light is emitted by each LED component 14, the temperature rises due to the self-generated heat of the LED components 14 and the emission efficiency decreases significantly, but in this embodiment each LED component 14 is cooled uniformly by the cooler 15 and thus this problem is suppressed.

[0023] The Fig. 4 and Fig. Figure 5 shows diagrams illustrating the configuration of the light shielding unit 20 of this embodiment. Fig. 4 is a cross-sectional view taken along line CC from Fig. 1B is recorded, and Fig. Figure 5 is an exploded perspective view. Furthermore, the light-shielding plates 27 are shown for illustrative purposes. Fig. 5 omitted. As in the Fig. 2 and Fig. As shown in Figure 3, the light shielding unit 20 is positioned opposite the light source unit 10 with the conveying passage 40 arranged between them, in order to shield UV light emitted by the light source unit 10 and prevent leakage. Furthermore, as shown in Figure 3, the light shielding unit 20 is arranged opposite the light source unit 10 with the conveying passage 40 positioned between them. Fig. Figure 3 shows that the light shielding unit 20 and the light source unit 10 are connected by a hinge 50, which is installed at one end along the X-axis, and the other end of the light shielding unit 20 along the X-axis can move about one end in the direction of rotation. Therefore, in this embodiment, when the light shielding unit 20 moves in the direction of rotation, the light shielding unit 20 and the light source unit 10 between them are placed in an open position, which makes it possible to easily install the target object P, e.g., a continuous feed paper, at the conveying passage 40.

[0024] As in the Fig. As shown in Figures 2 to 5, the light-shielding unit 20 comprises a light-absorbing element 22 and a container 21 (a housing) for receiving and holding the light-absorbing element 22. The container 21 is a box-shaped metal element with an opening 21e on the side of the conveying passage 40. Side plates 21a, 21b of the container 21, facing each other in the Y-axis direction, have a plurality of through-holes 21g for attaching the light-absorbing element 22. A side plate 21c in the X-axis direction of the container 21 has an air inlet 21f for introducing air from the outside, and a side plate 21d opposite side plate 21c has an exhaust fan 30 for expelling air from the container 21 to the outside. Furthermore, as shown in the Fig. 2 and Fig. Figure 4 shows a pair of light-shielding plates 27 installed in the side plates 21a, 21b of the container 21 of this embodiment. Each light-shielding plate 27 is a metal rod-shaped element with an approximately L-shaped cross-section in the YZ plane, and the planes 27a of the light-shielding plates 27 are attached to the top (the side opposite the Z-axis direction) of the side plates 21a, 21b such that they face the light-shielding plates 17. The surface of the planes 27a of each light-shielding plate 27 facing the light-shielding plates 17 (i.e., the surface of the side opposite the Z-axis direction) has a black electroless nickel plating or chrome plating, and when UV light from the light source unit 10 within the light-shielding unit 20 is reflected, each light-shielding plate 27 thus absorbs the reflected light to prevent leakage from the light-illuminating device 1.

[0025] Furthermore, the light-absorbing element 22 is a box-shaped metal element with an opening 22e on the side of the conveying passage 40, and a plurality of cylindrical protrusions 23 are attached to the side plates 22a, 22b of the light-absorbing element 22, which face each other in the Y-axis direction. In addition, the upper sides of the side plates 22c, 22d of the light-absorbing element 22, which face each other in the X-axis direction (opposite to the Z-axis direction), project beyond the side plates 22a, 22b, and the projections are wider than the underside, forming steps 22f and 22g, respectively. As in Fig. As shown in Figure 5, the light-absorbing element 22 of this embodiment is inserted into the opening 21e of the container 21 and secured. When the light-absorbing element 22 is inserted into the opening 21e of the container 21, its position in the Z-axis direction is determined by the contact of the steps 22f, 22g of the side plates 22c, 22d with the upper (the side opposite the Z-axis direction) cross-section of the side plates 21a, 21b of the container 21. Furthermore, in this case, the position of each protrusion 23 corresponds to the position of each through-hole 21g, and the light-absorbing element 22 is secured by a fastening screw (not shown) inserted into each through-hole 21g. Fig. 4 and Fig. 5), attached to the container 21. When the light-absorbing element 22 is fixed in the container 21, a connection is made between the light-absorbing element 22 and the container 21 (i.e., between the side plate 21a and the side plate 22a, between the side plate 21b and the side plate 22b, between a bottom plate 21h and a bottom plate 22h) ( Fig. 2) a space S was formed.

[0026] The inner surface of the light-absorbing element 22 of this embodiment has a black electroless nickel plating or chrome plating to absorb UV light from the light source unit 10, and, as indicated by the dashed arrow in Fig. As indicated in Figure 2, UV light from the LED components 14 enters the space between side plate 22a and side plate 22b. Accordingly, UV light from the light source unit 10 is absorbed by the light-absorbing element 22 upon contact, even if it partially extends outside the target object P, thus preventing light from escaping the lighting device 1. Furthermore, in this embodiment, as indicated by the dashed arrow in Figure 2, Fig. 3 specified to irradiate the target object P uniformly, the irradiation width of the X-axis direction of the light source unit 10 being longer than the width of the X-axis direction of the target object P, however, UV light which does not hit the target object P is absorbed by the light-absorbing element 22 upon contact, thereby preventing escape from the light illumination device 1.

[0027] Therefore, in this embodiment, the light-shielding unit 20 is positioned opposite the light source unit 10 with the conveying passage 40 arranged between them, thus preventing UV light emitted by the light source unit 10 from escaping. However, as described above, when UV light from the light source unit 10 is radiated onto the light-shielding unit 20, the temperature of the light-shielding unit 20 itself increases. To solve this problem, in this embodiment, space S is formed between the light-absorbing element 22 and the container 21 so that cooling air can flow into space S. More precisely, the side plate 21c of the container 21 has the air inlet 21f to introduce air from the outside into space S, and the exhaust fan 30 is arranged in the side plate 21d of the container 21 to discharge air from within space S to the outside, thus allowing cooling air to flow into space S. This means that room S acts as a kind of wind tunnel.

[0028] This means that when air from room S is expelled by rotation of the exhaust fan 30, room S has a negative pressure inside and air is introduced through a gap (a first air inlet) between the light-absorbing element 22 and the container 21 (see the solid arrow in Fig. 2) flows in the X-axis direction within room S and is discharged by the exhaust fan 30. When the air of room S is discharged by rotation of the exhaust fan 30, air is also drawn in through the air inlet 21f (a second air inlet) (see the solid arrow of Fig. 3) Introduced into space S, the air flows in the X-axis direction within space S and is discharged by the exhaust fan 30. Therefore, in this embodiment, the light-shielding unit 20 forms a wind tunnel between the light-absorbing element 22 and the container 21 to intensively cool the light-absorbing element 22, which is a heat source. Furthermore, the wind tunnel formed between the light-absorbing element 22, which is a heat source, and the container 21 (i.e., by fixing the light-absorbing element 22 to the housing by the protrusions 23) increases the thermal resistance between the light-absorbing element 22 and the container 21, thus preventing heat from being transferred from the light-absorbing element 22 to the container 21.

[0029] While this embodiment has been described above, the present disclosure is not limited to the configuration described above and various modifications may be made within the scope of the technical intent of the present disclosure.

[0030] For example, in this embodiment, the light shielding unit 20 and the light source unit 10 are connected by the hinge 50, which is installed at one end along the X-axis, and the other end along the X-axis of the light shielding unit 20 can rotate about one end, although the present disclosure is not limited to this. The light shielding unit 20 and the light source unit 10 can be formed in one piece, and the light shielding unit 20 and the light source unit 10 can be separated from each other along the Z-axis.

[0031] Although the inner surface of the light shielding unit 20 of this embodiment has a black electroless nickel plating or chrome plating to absorb UV light from the light source unit 10, an element for absorbing UV light can also be added to the inner surface of the box-shaped light shielding unit 20.

[0032] Furthermore, in this embodiment, the light-absorbing element 22 is fixed to the container 21 by the humps 23, although the fixing method is not limited to this. Any other method can be used to fix the light-absorbing element 22 in such a way that a wind tunnel is formed between the light-absorbing element 22 and the container 21 to allow cooling air to flow through it. (Variation)

[0033] Fig. Figure 6 is a diagram showing a variation of the light illumination device 1 according to an embodiment of the present disclosure. A light illumination device 1A according to this variation differs from the light illumination device 1 of this embodiment in that the shape of a light-absorbing element 22A, which is incorporated in a light-shielding unit 20A, is different.

[0034] In more detail, this includes, as in Fig. As shown in Figure 6, the light-absorbing element 22A of this variation comprises a pair of planes 22z formed by bending the upper part of the side plates 22a, 22b outwards (i.e., in the Y-axis direction and in a direction opposite to the Y-axis direction) so that the planes 22z face the light-shielding plates 17. Furthermore, the surface of the planes 22z facing the light-shielding plates 17 has a black electroless nickel plating or chrome plating. Thus, when UV light from the light source unit 10 is reflected within the light-shielding unit 20, the planes 22z absorb the reflected light to prevent leakage from the light-illuminating device 1A.

[0035] This means that in the light-absorbing element 22A of this variation there is an equivalent to the planes 27a of the light-shielding plates 27 of this embodiment ( Fig.2) (i.e., the pair of planes 22z) is formed in one piece, and the pair of planes 22z of the light-absorbing element 22A, which face the light-shielding plates 17, is received and supported in the housing. For this reason, this variation is better than this embodiment, as it is not necessary to install the light-shielding plates 27 separately, resulting in a simpler assembly process.

[0036] Furthermore, it should be understood that the disclosed embodiments are illustrative in all aspects and not limiting. The scope of this disclosure is defined by the attached claims and not by the preceding description, and is intended to include all modifications within the attached claims and their equivalent meaning and scope. [Detailed description of the main elements] 1... Light illuminating device 1A... Light illuminating device 10... Light source unit 11... Containers 12... windows 13... Substrat 14... LED component 15... Cooler 16... Heat dissipation fin 17... Light shielding plate 20... Light shielding unit 20A... Light shielding unit 21... Housing 21a... Side panel 21b... Side panel 21c... side panel 21d... side panel 21e... Opening 21f... Air intake 21g... through hole 21h... Base plate 22... Light-absorbing element 22A... Light-absorbing element 22a... Side panel 22b... side panel 22c... side panel 22d... side panel 22e... Opening 22f... level 22g... level 22h... Base plate 22z... level 23... humps 27... Light shielding plate 27a... Level 30... Exhaust fan 40... Conveyor cycle 50... hinge P... Target object S... room

Claims

[1] Light illumination device for shining light onto a target object being transported along a first direction, the light illumination device comprising: a light source unit with a plurality of light-emitting diode (LED) components to shine light onto the target object from a second direction perpendicular to the first direction; and a light shielding unit positioned opposite the light source unit with an intermediate conveying passage for the target object to shield the light emitted by the light source unit in order to prevent escape; the light shielding unit includes: a light-absorbing element to absorb the light emitted by the light source unit; a housing to accommodate and hold at least part of the light-absorbing element; and a wind tunnel formed between the housing and the light-absorbing element to allow cooling air to flow. [2] Light illumination device according to claim 1, wherein the housing is in the form of a box with an opening on the conveying side and has a first air inlet in at least a part of the opening to introduce air from outside into the wind tunnel. [3] Light illumination device according to claim 2, wherein the housing has a second air inlet at one end in a third direction perpendicular to the first direction and the second direction to introduce air from outside into the wind tunnel. [4] Light illumination device according to claim 2 or claim 3, wherein the housing has an exhaust fan at the other end in the third direction perpendicular to the first direction and the second direction for discharging air inside the wind tunnel to the outside. [5] Light illumination device according to any one of claims 1 to 4, wherein the light-absorbing element is in the form of a box with an opening on the conveying side and is attached to the housing at a predetermined distance from the housing. [6] Light illumination device according to claim 5, wherein the light-absorbing element has a black electroless nickel plating or chrome plating on an inner surface. [7] Light illumination device according to claims 1 to 6, wherein the light source unit and the light shielding unit are connected at one end by a hinge. [8] Light illumination device according to any one of claims 1 to 7, wherein the light emitted by the light source unit is ultraviolet light.

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