Light irradiation device

Abstract

The present invention provides a compact light irradiation device with a configuration that allows for uniform cooling of multiple LEDs without exhausting air in the transport direction. [Solution] The light irradiation device comprises a light source unit having a substrate and a plurality of light sources arranged on the surface of the substrate, a heat dissipation unit having a plurality of heat dissipation fins and thermally coupled to the back side of the substrate, a housing that houses the heat dissipation unit, and a cooling fan that generates cooling air to cool the heat dissipation unit inside the housing, wherein the housing has a partition plate that divides the space inside the housing and forms a first space where the heat dissipation unit is arranged and a second space, a communication port that connects the first space and the second space so that the base ends of the plurality of heat dissipation fins are exposed to the second space, an intake port formed on the upper surface of the housing that communicates with the first space, and an exhaust port formed on the side of the housing that communicates with the second space.

Description

Technical Field

[0005] ,

[0004] , ,

[0001] The present invention relates to a light irradiation device that is disposed on the downstream side of a recording head that applies ink onto a printing medium and cures the ink on the printing medium.

Background Art

[0002] Conventionally, a printing apparatus that performs printing using a UV ink that cures by irradiation with ultraviolet light has been known. In such a printing apparatus, after ink is applied from the nozzles of the head to the medium, the dots formed on the medium are irradiated with ultraviolet light. By the irradiation with ultraviolet light, the dots are cured and fixed on the medium, so that good printing can be performed even on a medium that is difficult to absorb liquid.

[0003] In an ultraviolet light irradiation device used in such a printing apparatus, in recent years, due to the demands for reduction of power consumption, extension of service life, and downsizing of the apparatus size, instead of a conventional discharge lamp, an apparatus that uses an LED (Light Emitting Diode) element as a light source has been put into practical use. <000​​​​​Furthermore, when using LEDs as a light source, as in the light irradiation device described in Patent Document 1, most of the power input is converted into heat, leading to problems such as reduced luminous efficiency and lifespan due to the heat generated by the LEDs themselves. In addition, the heat generated by the LEDs causes the light irradiation device itself (i.e., the housing) to become hot, making it impossible to place surrounding components close together, resulting in the overall device becoming larger. For this reason, such light irradiation devices use cooling devices with heat sinks or cooling fans to efficiently cool the LEDs.

[0006] For example, Patent Document 2 describes a light irradiation device equipped with multiple LEDs arranged on a substrate along the width direction of the printing medium, multiple heat dissipation fins arranged on the back surface of the substrate to release heat from the LEDs, a cooling fan, and the like. The cooling air generated by the cooling fan is configured to pass between the multiple fins, thereby efficiently cooling the LEDs. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-252720 [Patent Document 2] Japanese Patent Publication No. 2019-057471 [Overview of the project] [Problems that the invention aims to solve]

[0008] Thus, to suppress the heat generated by LEDs, it is effective to use heat dissipation components such as heat sinks. However, in a configuration in which multiple LEDs are arranged in a row, such as the light irradiation device in Patent Document 2, if cooling air is flowed along the direction of the LED arrangement, the temperature of the air rises as the cooling air (i.e., air) moves. As a result, the cooling efficiency differs between the heat sink on the air intake side and the heat sink on the exhaust side, making it impossible to cool each LED uniformly. If each LED is not cooled uniformly (i.e., if the temperature is not roughly uniform), variations in light intensity will occur due to temperature differences between each LED, and variations will also occur in the curing of UV-curable ink on the printing medium.

[0009] Furthermore, when the light irradiation device is incorporated into a printing apparatus, as described in Patent Document 1, it is desirable that the light irradiation device be as small as possible, since it is positioned between each recording head aligned in the transport direction. Also, since the high-temperature air exhausted from the light irradiation device can change the viscosity of the ink inside the recording head if it hits an adjacent recording head, there is a need for a light irradiation device that does not exhaust air in the transport direction.

[0010] The present invention has been made in view of the above circumstances, and its object is to provide a compact light irradiation device having a configuration that enables uniform cooling of multiple LEDs without exhausting air in the conveying direction. [Means for solving the problem]

[0011] To achieve the above objective, the present invention provides a light irradiation device that is positioned downstream in the first direction of a recording head that applies ink to a printing medium being transported in a first direction, and is a light irradiation device for curing ink on a printing medium, comprising: a substrate defined by a second direction perpendicular to the first direction and the first direction; a plurality of light sources arranged in a line along the second direction on the surface of the substrate and emitting light in a third direction perpendicular to the first and second directions; a light source unit that irradiates the printing medium with line-shaped light; and a plurality of heat dissipation fins erected at predetermined intervals along the second direction, which are thermally coupled to the back side of the substrate. The device comprises a heat dissipation unit, a housing for the heat dissipation unit, and a cooling fan within the housing that generates cooling air to cool the heat dissipation unit. The housing is characterized by having a partition plate that divides the space inside the housing in a first direction, forming a first space where the heat dissipation unit is located and a second space, a communication port that connects the first space and the second space and extends in a second direction so that the base ends of a plurality of heat dissipation fins are exposed in the second space, an intake port formed on the end face of the housing in a direction opposite to the third direction so as to communicate with the first space, and an exhaust port formed on the end face of the housing in a direction opposite to the second direction so as to communicate with the second space.

[0012] With this configuration, the heat dissipation fins arranged in the first space are uniformly cooled by the cooling air from the cooling fan, thus suppressing variations in light intensity between each light source. Furthermore, since the exhaust port is formed on the end face in the second direction of the housing, hot air is not exhausted in the direction of transporting the printing medium. In addition, since the intake port is formed on a different surface from the exhaust port (i.e., the end face in the direction opposite to the third direction of the housing), hot air is not drawn in, and the heat dissipation fins arranged in the first space can be cooled stably.

[0013] From another perspective, the present invention is a light irradiation device positioned downstream in the first direction of a recording head that applies ink to a printing medium being transported in the first direction, and is a light irradiation device for curing the ink on the printing medium, comprising: a substrate defined by a second direction perpendicular to the first direction and the first direction; a plurality of light sources arranged in a line along the second direction on the surface of the substrate and emitting light in a third direction perpendicular to the first and second directions; a light source unit that irradiates the printing medium with line-shaped light; and a plurality of heat dissipation fins erected at predetermined intervals along the second direction, and thermally coupled to the back side of the substrate. The device comprises a heat-generating component, a housing that houses the heat-dissipating component, and a cooling fan within the housing that generates cooling air to cool the heat-dissipating component. The housing is characterized by having a partition plate that divides the space inside the housing in a first direction, forming a first space where the heat-dissipating component is located and a second space, a communication port that connects the first space and the second space and extends in a second direction so that the base ends of a plurality of heat-dissipating fins are exposed in the second space, an intake port formed on the end face of the housing in a direction opposite to the second direction so as to communicate with the second space, and an exhaust port formed on the end face of the housing in a direction opposite to the third direction so as to communicate with the first space.

[0014] Furthermore, it is desirable that N cooling fans (where N is an integer greater than or equal to 2) be provided along the second direction, so as to be opposite the multiple heat dissipation fins in the third direction.

[0015] Furthermore, it is desirable that the partition plate consists of a pair of plates arranged to sandwich the heat dissipation section from a first direction, and that two second spaces are formed within the housing, flanking the first space.

[0016] Furthermore, in the second space, partition plates can be provided that divide the communication opening into multiple regions along the second direction and straighten the cooling air passing through the communication opening. In this case, it is desirable that (N-1) partition plates be provided so that the communication opening is divided into N regions corresponding to N cooling fans.

[0017] Further, a light shielding unit can be provided which is connected to the housing so as to sandwich the conveyance path of the irradiation object from the third direction and shields light so that the light emitted from the light source unit does not leak to the outside. In this case, it is desirable that the light shielding unit has a hollow box-shaped main body portion with a light shielding surface formed at a position facing the light source unit. In this case, the housing has a first opening communicating with the second space at an end portion in the second direction of the end surface in the third direction, and the main body portion has a second opening communicating with the internal space of the main body portion at a position facing the first opening, and it is desirable that the main body portion has a third opening formed so as to communicate with the internal space on the end surface in the second direction. In this case, it is desirable that the internal space has a heat sink thermally coupled to the light shielding surface.

[0018] Further, a filter can be provided which is arranged so as to cover the air inlet and adsorbs ink mist.

Advantages of the Invention

[0019] As described above, according to the present invention, a small-sized light irradiation device capable of uniformly cooling a plurality of LEDs without exhausting air in the conveyance direction is realized.

Brief Description of the Drawings

[0020] [Figure 1] It is an external view of the light irradiation device according to the first embodiment of the present invention. [Figure 2] It is an external view of the light irradiation device according to the first embodiment of the present invention. [Figure 3] It is a diagram for explaining the internal configuration of the light irradiation device according to the first embodiment of the present invention. [Figure 4] It is a schematic diagram for explaining the configuration of the light source unit and the heat radiating member provided in the light irradiation device according to the first embodiment of the present invention. [Figure 5] [[ID=三十二]] [[ID=三十三]] [Figure 6] [[ID=三十四]]It is a diagram for explaining the internal configuration of the light irradiation device according to the third embodiment of the present invention. <00**********93> [Figure 7] ​It is an external view of a light irradiation device according to a fourth embodiment of the present invention. [Figure 8] It is an external view of a light irradiation device according to a fourth embodiment of the present invention. [Figure 9] It is a diagram for explaining the internal configuration of a light irradiation device according to a fourth embodiment of the present invention. [Figure 10] It is a diagram for explaining the internal configuration of a light irradiation device according to a fifth embodiment of the present invention. [Figure 11] It is an external view of a light irradiation device according to a sixth embodiment of the present invention.

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0022] (First Embodiment) FIGS. 1 and 2 are diagrams showing the configuration of a light irradiation device 1 according to the first embodiment of the present invention. FIG. 1(a) is a perspective view, and FIG. 1(b) is a front view. Further, FIG. 2(a) is a plan view of the light irradiation device 1, FIG. 2(b) is a bottom view, and FIG. 2(c) is a left side view. As shown in FIGS. 1 and 2, the light irradiation device 1 of the present embodiment is a light source device that is incorporated into a printing device or the like and cures ultraviolet curable ink or ultraviolet curable resin. It is disposed above an irradiation object P (for example, a recording medium or the like) that is conveyed in one direction, and emits linear ultraviolet light to the irradiation object P. In FIG. 1(a), only the light irradiation device 1 is shown for convenience of explanation, but in an actual printing device or the like, a plurality of recording heads that respectively apply different color inks are arranged in the conveyance direction of the irradiation object P, and the light irradiation device 1 is disposed in a narrow space on the downstream side of each recording head. In this specification, the conveyance direction of the irradiation object P is defined as the X-axis direction (first direction), the arrangement direction of LED (Light Emitting Diode) elements 210 described later is defined as the Y-axis direction (second direction), and the direction in which the LED elements 210 emit ultraviolet light is defined as the Z-axis direction for explanation.

[0023] As shown in Figures 1 and 2, the light irradiation device 1 of this embodiment includes a box-shaped housing 100 that is long in the Y-axis direction and houses a light source unit 200 and the like. The housing 100 has a glass window 105 on its bottom surface from which ultraviolet light is emitted. On the left side of the housing 100, there is an exhaust port 101 formed of multiple small holes for exhausting air from inside the housing 100, and on the top surface of the housing 100, there are six intake ports 103 for supplying air into the housing 100, with a cooling fan 300 positioned corresponding to each intake port 103. The light irradiation device 1 is electrically connected to a power supply unit (not shown) and power is supplied from the power supply unit.

[0024] Figure 3 is a diagram illustrating the internal configuration of a light irradiation device 1 according to an embodiment of the present invention. Figure 3(a) is a cross-sectional view along line BB of Figure 2(a), Figure 3(b) is a cross-sectional view along line CC of Figure 2(b), and Figure 3(c) is a cross-sectional view along line AA of Figure 1(b). In Figure 3, some components, such as the internal wiring cables of the light irradiation device 1, are omitted for clarity.

[0025] As shown in Figure 3, the light irradiation device 1 of this embodiment is housed in a housing 100 and comprises six light source units 200 arranged in the Y-axis direction, six heat dissipation members 400 arranged in the Y-axis direction, six LED drive circuits 500, etc. Each light source unit 200, each heat dissipation member 400, and each LED drive circuit 500 has exactly the same configuration.

[0026] Figure 4 is a schematic diagram illustrating the configuration of the light source unit 200 and heat dissipation member 400 of this embodiment, where Figure 4(a) is a view from the Z-axis direction and Figure 3(b) is a view from the X-axis direction. As shown in Figure 4, the light source unit 200 comprises a rectangular plate-shaped substrate 205 defined in the X-axis and Y-axis directions, and a plurality (for example, 10) LED elements 210 having the same characteristics, and is fixed on one end face (the end face in the Z-axis direction) of the heat dissipation plate 410 of the heat dissipation member 400.

[0027] Multiple LED elements 210 are arranged in a line on the surface of a substrate 205 at predetermined intervals in the Y-axis direction, with their optical axes aligned in the Z-axis direction, and are electrically connected to the substrate 205. The substrate 205 is also electrically connected by wiring cables (not shown) extending from an LED drive circuit 500, and each LED element 210 is supplied with a drive current from the LED drive circuit 500. When a drive current is supplied to each LED element 210, ultraviolet light (for example, wavelength 365 nm) with an intensity corresponding to the drive current is emitted from each LED element 210, and a line-shaped ultraviolet light extending in the Y-axis direction and having a predetermined line width in the X-axis direction is emitted from the light source unit 200. As shown in Figure 4, in this embodiment, six light source units 200 are arranged in a line in the Y-axis direction, and the line-shaped ultraviolet light emitted from each light source unit 200 is continuous in the Y-axis direction.

[0028] The heat dissipation member 400 is a member that dissipates heat emitted from the light source unit 200. The heat dissipation member 400 in this embodiment consists of a rectangular plate-shaped metal (e.g., copper, aluminum) heat sink 410 and a plurality of heat dissipation fins 420 brazed to the other end face of the heat sink 410 (the face opposite to the surface on which the light source unit 200 is placed) (Figure 4(b)). The heat dissipation fins 420 are rectangular plate-shaped metal (e.g., copper, aluminum, iron, magnesium, or alloys containing these) members that are erected at predetermined intervals along the Y axis so as to protrude from the heat sink 410 in a direction opposite to the Z axis, and dissipate the heat transferred to the heat sink 410 into the air. As will be described in more detail later, in this embodiment, the cooling fan 300 draws air into the housing 100 from the outside, the drawn-in air flows between the heat dissipation fins 420 as cooling air, and the air heated by the heat dissipation fins 420 is quickly exhausted through the exhaust port 101.

[0029] As shown in Figure 3(c), the housing 100 of this embodiment includes a partition plate 110 that divides the space inside the housing 100 in the X-axis direction, forming a first space α where the heat dissipation member 400, LED drive circuit 500, and cooling fan 300 are arranged, and a second space β adjacent to the first space α. A communication opening 120 is formed on the Z-axis side of the partition plate 110, connecting the first space α and the second space β so that the base ends (Z-axis side) of the multiple heat dissipation fins 420 are exposed to the second space β. As shown in Figure 3(a), in this embodiment, six communication openings 120 are formed along the Y-axis direction corresponding to the six heat dissipation members 400, but these can also be connected to form a single communication opening 120 extending in the Y-axis direction. As will be described in detail later, the first space α and the second space β of this embodiment function as wind tunnels through which cooling air flows to cool the heat dissipation fins 420.

[0030] In this embodiment, the drive current supplied to each LED element 210 is adjusted so that it emits ultraviolet light of a substantially uniform intensity, and the linear ultraviolet light emitted from the light source unit 200 has a substantially uniform light intensity distribution in the Y-axis direction.

[0031] When a drive current flows through each LED element 210 and ultraviolet light is emitted from each LED element 210, the temperature of the LED element 210 rises due to self-heating. However, the heat generated by each LED element 210 is quickly conducted (transferred) to the heat dissipation fins 420 via the substrate 205 and the heat sink 410, and the heat is dissipated into the surrounding air from each heat dissipation fin 420. The air heated by the heat dissipation fins 420 is then quickly exhausted through the exhaust port 101 by the cooling air flowing over the surface of each heat dissipation fin 420.

[0032] In this embodiment, the configuration involves six light source units 200 and heat dissipation members 400 arranged in a line along the Y-axis. However, if the LED elements 210 of each light source unit 200 have different temperatures, variations in light intensity will occur. Therefore, in order to achieve uniform light intensity, the six heat dissipation members 400 must be cooled uniformly, which presents a challenge. Furthermore, when the light irradiation device 1 is incorporated into a printing device or the like, it is located in a very narrow space between each recording head. Additionally, if the high-temperature air exhausted from the light irradiation device 1 hits the recording head, it will alter the viscosity of the ink inside the recording head. This presents a challenge in that the air cannot be exhausted in the transport direction. To address these challenges, in this embodiment, six cooling fans 300 are arranged in the first space α so as to face the six heat dissipation members 400. The direction of the cooling airflow is also changed between the first space α and the second space β, and the air is exhausted from an exhaust port 101 provided on the left side of the housing 100 (i.e., in a direction opposite to the Y-axis).

[0033] The following describes the cooling action of the cooling air flowing within the housing 100 and the heat dissipation member 400, which are key features of the present invention. Each solid arrow in Figure 3 indicates the direction of the cooling air within the housing 100.

[0034] As shown in Figure 3(b), the light irradiation device 1 of this embodiment is equipped with six cooling fans 300 in an intake port 103 formed on the upper surface (the side opposite to the Z-axis direction) of the housing 100, facing the six heat dissipation members 400. Also, as shown in Figure 3(a), an exhaust port 101 is formed on the left side of the housing 100. When the six cooling fans 300 rotate, air from outside the housing 100 is drawn in by the cooling fans 300, generating a cooling airflow in the Z-axis direction in the first space α of the housing 100. This cooling airflow then flows in the Z-axis direction while cooling the LED drive circuit 500 located in the first space α, and is supplied between the heat dissipation fins 420 of the heat dissipation members 400 facing each cooling fan 300 (Figures 3(b) and 3(c)). The cooling air that reaches the heat dissipation fin 420 is deflected at the base end of the heat dissipation fin 420 (i.e., the heat sink 410) in a direction opposite to the X-axis direction, and flows through the communication port 120 into the second space β. When the cooling air flows into the second space β, the pressure inside the second space β becomes positive, so the air inside the housing 100 is exhausted from the exhaust port 101 (Figure 3(a)). In other words, cooling air is generated inside the housing 100, as shown by the solid arrows in Figure 3.

[0035] As described above, in this embodiment, six cooling fans 300 are provided facing the six heat dissipation members 400, so that the amount of air flowing between each heat dissipation fin 420 is substantially uniform, and each heat dissipation member 400 is cooled substantially uniformly. Furthermore, in this embodiment, the direction of the cooling air is changed by the second space β and exhausted from the exhaust port 101 provided on the left side of the housing 100 (i.e., the side opposite to the Y-axis direction), so even if the light irradiation device 1 is placed in the narrow space of the printing device, hot air will not be exhausted toward the recording head or the like which is close in the transport direction. In addition, since the surface on which the intake port 103 is formed (the side opposite to the Z-axis direction) and the surface on which the exhaust port 101 is formed (the side opposite to the Y-axis direction) are different, hot air is not drawn into the housing 100, and the heat dissipation fins 420 placed in the first space α can be cooled stably. Furthermore, it is desirable that the opening area of ​​the exhaust port 101 be larger than the opening area of ​​the communication port 120 so that the air in the second space β is efficiently exhausted from the exhaust port 101.

[0036] The above describes this embodiment, but the present invention is not limited to the above configuration, and various modifications are possible within the scope of the technical idea of ​​the present invention.

[0037] For example, although the light irradiation device 1 of this embodiment has been described as comprising six light source units 200 arranged in a line along the Y-axis and a heat dissipation member 400, the number of light source units 200 and heat dissipation members 400 can be appropriately set according to the required specifications. Alternatively, instead of a configuration comprising multiple light source units 200 and heat dissipation members 400, a configuration comprising one light source unit 200 extending in the Y-axis direction and a heat dissipation member 400 can also be used.

[0038] In this embodiment, six cooling fans 300 are provided facing the six heat dissipation members 400, but it is sufficient if all heat dissipation members 400 are cooled evenly, and the number of cooling fans 300 can be appropriately set according to the amount of heat generated by the LED elements 210 and the capacity of the cooling fans 300. In addition, the cross-sectional area of ​​the first space α of the housing 100 may be increased near the top surface of the housing 100 to further increase the total opening area of ​​the air intake ports 103. For example, the partition plate 110 may be bent near the top surface of the housing 100 so that the air intake ports 103 can be arranged across the entire top surface of the housing 100.

[0039] Furthermore, although the cooling fan 300 in this embodiment has been described as supplying air into the housing 100, it is not necessarily limited to this configuration, and the cooling fan 300 can also be used as an exhaust fan. In this case, the exhaust port 101 in this embodiment functions as an intake port, and the direction of the cooling air in Figure 3 is reversed.

[0040] (Second embodiment) Figure 5 is a cross-sectional view illustrating the internal configuration of a light irradiation device 2 according to a second embodiment of the present invention. Figure 5(a) is a cross-sectional view corresponding to Figure 3(a) of the first embodiment, and Figure 5(b) is a cross-sectional view corresponding to Figure 3(c) of the first embodiment. As shown in Figure 5, the light irradiation device 2 of this embodiment differs from the light irradiation device 1 of the first embodiment in that it is equipped with five partition plates 112 arranged in the second space β so as to partition each of the multiple communication openings 120 (i.e., so as to partition into multiple regions along the second direction) and rectifies the cooling air passing through the communication openings 120. When the partition plates 112 are arranged in the second space β in this way, the cooling air that reaches the heat dissipation fins 420 flows into the second space β through the communication openings 120 and is deflected by the partition plates 112 in a direction opposite to the Z-axis direction (Figure 5(b)). Therefore, the flow of cooling air flowing into the second space β from each communication port 120 is not affected by the cooling air from adjacent communication ports 120, and the flow of cooling air in the second space β is stable.

[0041] (Third embodiment) Figure 6 is a cross-sectional view illustrating the internal configuration of a light irradiation device 3 according to a third embodiment of the present invention. Figure 6(a) is a cross-sectional view corresponding to Figure 3(a) of the first embodiment, and Figure 6(b) is a cross-sectional view corresponding to Figure 3(c) of the first embodiment. As shown in Figure 6(b), the light irradiation device 3 of this embodiment differs from the light irradiation device 1 of the first embodiment in that the partition plate 110 consists of a pair of plates 110a and 110b arranged to sandwich the heat dissipation member 400 from the X-axis direction, two second spaces β are formed within the housing 100 with a first space α in between, and the cooling fan 300 is positioned close to the heat dissipation member 400. In this way, with the pair of plates 110a and 110b arranged within the housing 100, air from outside the housing 100 is taken in from the intake port 103, flows through the first space α of the housing 100 in the Z-axis direction, and is supplied between the heat dissipation fins 420 of the heat dissipation member 400 facing each cooling fan 300. The cooling air that reaches the heat dissipation fins 420 is deflected at the base end of the heat dissipation fins 420 in the X-axis direction and in directions opposite to the X-axis direction, and flows through the communication port 120 into the two second spaces β (Figure 6(b)). When the cooling air flows into each second space β, the pressure inside each second space β becomes positive, and the air inside the housing 100 is exhausted from the exhaust port 101 which is in communication with each second space β (Figure 6(a)). In other words, cooling air is generated inside the housing 100, as shown by the solid arrows in Figure 6.

[0042] Thus, in this embodiment, two second spaces β are formed on either side of the first space α. As a result, the opening area (sum of opening areas) of the communication port 120 is larger compared to the first embodiment. Consequently, the airflow rate of the cooling air can be increased compared to the first embodiment, and the heat dissipation fins 420 arranged in the first space α can be cooled more stably.

[0043] (Fourth embodiment) Figures 7 and 8 show the configuration of a light irradiation device 4 according to the fourth embodiment of the present invention, where Figure 7(a) is a perspective view and Figure 7(b) is a front view. Also, Figure 8(a) is a plan view of the light irradiation device 4, Figure 8(b) is a bottom view, and Figure 8(c) is a left side view. Furthermore, Figure 9 illustrates the internal configuration of the light irradiation device 4, where Figure 9(a) is a cross-sectional view along line LL of Figure 8(a), Figure 9(b) is a cross-sectional view along line MM of Figure 8(b), and Figure 9(c) is a cross-sectional view along line KK of Figure 7(b). As shown in Figures 7 to 9, the light irradiation device 4 of this embodiment differs from the light irradiation device 2 of the second embodiment in that it includes a light-shielding unit 600 that is positioned opposite the housing 100 across the transport path 50 for the object to be irradiated P. Furthermore, the light irradiation device 4 of this embodiment differs from the light irradiation device 2 of the second embodiment in that it has openings 108 (first openings) that communicate with the second space β at both ends in the Y-axis direction of the bottom surface (end surface in the Z-axis direction) of the housing 100.

[0044] As shown in Figures 7 to 9, the light-shielding unit 600 is positioned opposite the housing 100 across the transport path 50 and is a device that shields ultraviolet light emitted from the light source unit 200 from leaking to the outside. Furthermore, as shown in Figure 8, the light-shielding unit 600 and the housing 100 are connected by a hinge 150 provided at one end in the Y-axis direction, and the other end of the light-shielding unit 600 in the Y-axis direction is configured to be movable in the rotational direction around the one end. In this embodiment, as the light-shielding unit 600 moves in the rotational direction, the space between the light-shielding unit 600 and the housing 100 is opened, making it possible to easily place the object to be irradiated P, such as continuous paper, on the transport path 50.

[0045] As shown in Figures 7 to 9, the light-shielding unit 600 has a hollow box-shaped metal body 601. A light-shielding surface 602 is formed on the body 601 at a position facing the light source unit 200 to block ultraviolet light from the light source unit 200, and an opening 608 (second opening) is formed at a position facing the opening 108, communicating with the internal space γ of the body 601. In addition, an exhaust port 603 (third opening) formed of multiple small holes is formed on the left side of the body 601 to exhaust air from inside the body 601. Furthermore, the internal space γ of the body 601 is equipped with a heat sink 620 that is thermally coupled to the light-shielding surface 602. Rectangular plate-shaped heat dissipation fins 621 are formed on the heat sink 620, which are erected at predetermined intervals along the X-axis so as to protrude in the Z-axis direction, and dissipate the heat transferred to the heat sink 620 into the air.

[0046] In this embodiment as well, when the six cooling fans 300 rotate, air from outside the housing 100 is drawn in by the cooling fans 300, generating a cooling airflow in the Z-axis direction in the first space α of the housing 100. The cooling airflow then flows in the Z-axis direction while cooling the LED drive circuit 500 located in the first space α, and is supplied between the heat dissipation fins 420 of the heat dissipation member 400 facing each cooling fan 300 (Figures 9(b) and 9(c)). The cooling air that reaches the heat dissipation fins 420 is deflected in a direction opposite to the X-axis direction at the base end of the heat dissipation fins 420 (i.e., the heat sink 410), flows through the communication opening 120 into the second space β, and is further deflected in a direction opposite to the Z-axis direction by the partition plate 112 (Figure 9(c)). When the cooling air flows into the second space β, the pressure inside the second space β becomes positive, so the air inside the second space β is exhausted from the exhaust port 101, and at the same time, a portion of the air inside the second space β (i.e., a portion of the cooling air) enters the internal space γ through the openings 108 and 608. The cooling air that enters the internal space γ then flows between the heat sink 621 fins 621, cools the heat sink fins 621, and is exhausted from the exhaust port 603 (Figure 9(a)).

[0047] As described above, the light irradiation device 4 of this embodiment includes a light-shielding unit 600 that shields ultraviolet light from the light source unit 200. However, since the light-shielding surface 602 becomes hot when exposed to ultraviolet light, a portion of the cooling air inside the housing 100 is introduced into the internal space γ of the main body 601 of the light-shielding unit 600, thereby cooling the light-shielding surface 602. Therefore, according to the configuration of this embodiment, it is possible to prevent the light-shielding surface 602 from becoming hot.

[0048] In this embodiment, the main body 601 is configured to have a heat sink 620 thermally coupled to the light-shielding surface 602 in its internal space γ. However, if the light-shielding surface 602 can be sufficiently cooled by the cooling air passing through the internal space γ, it is not necessarily required to provide the heat sink 620.

[0049] Furthermore, the surface of the light-shielding surface 602 can be coated with a black electroless nickel plating or chromium plating that absorbs ultraviolet light from the light source unit 200.

[0050] Furthermore, it is desirable that the total opening area of ​​exhaust ports 101 and 603 be larger than the opening area of ​​the communication port 120, so that the air in the second space β is efficiently exhausted from exhaust ports 101 and 603.

[0051] Furthermore, in this embodiment, the light irradiation device 4 is provided with openings 108 (first openings) that communicate with the second space β at both ends in the Y-axis direction of the bottom surface (end surface in the Z-axis direction) of the housing 100, and an opening 608 (second opening) that communicates with the internal space γ of the main body 601 is formed at a position opposite to the opening 108 of the light shielding unit 600. However, the openings 108 (first openings) and 608 (second openings) do not necessarily need to be provided at both ends in the Y-axis direction; it is sufficient to provide one on the downstream side in the Y-axis direction.

[0052] (Fifth embodiment) Figure 10 is a cross-sectional view illustrating the internal configuration of the light irradiation device 5 according to the fifth embodiment of the present invention. Figure 10(a) is a cross-sectional view corresponding to Figure 9(a) of the fourth embodiment, and Figure 10(b) is a cross-sectional view corresponding to Figure 9(c) of the fourth embodiment. As shown in Figure 10(b), the light irradiation device 5 of this embodiment is configured by attaching the light shielding unit 600 of the fourth embodiment to the light irradiation device 3 of the third embodiment. Note that the light irradiation device 5 of this embodiment differs from the light irradiation device 4 of the fourth embodiment in that it has one opening 108 (first opening) and one opening 608 (second opening) on ​​the downstream side in the Y-axis direction.

[0053] Similar to the light irradiation device 3 of the third embodiment, the light irradiation device 5 of this embodiment has a pair of plates 110a and 110b that sandwich the heat dissipation member 400 from the X-axis direction, and two second spaces β are formed within the housing 100 with a first space α in between. When each cooling fan 300 rotates, air from outside the housing 100 is taken in from the intake port 103, flows through the first space α of the housing 100 in the Z-axis direction, and is supplied between the heat dissipation fins 420 of the heat dissipation member 400 that are facing each cooling fan 300. The cooling air that reaches the heat dissipation fins 420 is deflected at the base end of the heat dissipation fins 420 in the X-axis direction and in opposite directions to the X-axis direction, and flows through the communication port 120 into the two second spaces β (Figure 10(b)). As the cooling air flows into each second space β, the pressure inside each second space β becomes positive. As a result, the air inside the housing 100 is exhausted from the exhaust port 101, which is connected to each second space β, and a portion of the air inside each second space β (i.e., a portion of the cooling air) enters the internal space γ through the openings 108 and 608 (Figure 10(a)). The cooling air that enters the internal space γ then flows between the heat dissipation fins 621 of the heat sink 620, cooling the heat dissipation fins 621, and is exhausted from the exhaust port 603 (Figure 10(a)). In other words, cooling air is generated inside the housing 100, as indicated by the solid arrows in Figure 10.

[0054] As described above, the light irradiation device 5 of this embodiment includes a light-shielding unit 600 that shields ultraviolet light from the light source unit 200. However, since a portion of the cooling air inside the housing 100 flows through the internal space γ of the main body 601 of the light-shielding unit 600, it is possible to prevent the light-shielding surface 602 from becoming hot. Furthermore, in this embodiment, as in the third embodiment, two second spaces β are formed on either side of the first space α, so the opening area (sum of opening areas) of the communication port 120 is larger compared to the fourth embodiment. Therefore, the amount of cooling air can be increased compared to the fourth embodiment, and the heat dissipation fins 420 arranged in the first space α and the heat dissipation fins 621 arranged in the internal space γ can be cooled more stably.

[0055] (Sixth embodiment) Figure 11 shows the configuration of a light irradiation device 6 according to a fourth embodiment of the present invention, where Figure 11(a) is a plan view of the light irradiation device 6 and Figure 11(b) is a left side view. As shown in Figure 11, the light irradiation device 6 of this embodiment differs from the light irradiation device 1 of the first embodiment in that it is equipped with a filter 700 that covers the cooling fan 300 and the air intake port 103 on the upper surface of the housing 100. The filter 700 is, for example, a paper filter and has the function of adsorbing ink mist around the air intake port 103.

[0056] According to the configuration of this embodiment, even if the light irradiation device 6 is placed in a space filled with ink mist, the filter 700 can adsorb the ink mist, thereby preventing the ink mist from entering the housing 100.

[0057] Similar to the first embodiment, the cooling fan 300 in this embodiment has been described as supplying air into the housing 100, but the cooling fan 300 can also be used as an exhaust fan. In this case, since the exhaust port 101 functions as an intake port, the filter 700 should be positioned to cover the exhaust port (intake port) 101.

[0058] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0059] 1:Light irradiation device 2:Light irradiation device 3:Light irradiation device 4:Light irradiation device 5:Light irradiation device 6:Light irradiation device 50: Conveyor path 100: Cabinet 101: Exhaust vent 103: Air intake 105: Window section 108 :Aperture 110: Partition plate 110a: Plate 110b: Plate 112: Partition plate 120: Communication port 150: Hinge 200: Light source unit 205: Circuit board 210: LED element 300: Cooling fan 400: Heat dissipation component 410: Heat sink 420: Heat dissipation fins 500: LED driver circuit 600: Light-blocking unit 601: Main body 602: Shading mask 603: Exhaust vent 608 :Aperture 620: Heatsink 621: Heat dissipation fins 700: Filter P: Object to be irradiated α :first space β :Second space γ :Inner space

Claims

1. A light irradiation device is positioned downstream in the first direction of a recording head that applies ink to a printing medium being transported in a first direction, and cures the ink on the printing medium, A light source unit comprising a substrate defined by a second direction perpendicular to the first direction and the first direction, and a plurality of light sources arranged in a line along the second direction on the surface of the substrate and emitting light in a third direction perpendicular to the first and second directions, wherein the light source unit irradiates the printing medium with line-shaped light, The heat dissipation portion has a plurality of heat dissipation fins erected at predetermined intervals along the second direction and is thermally coupled to the back side of the substrate, A housing that houses the heat dissipation unit, The enclosure contains a cooling fan that generates cooling air to cool the heat dissipation section, Equipped with, The aforementioned enclosure is A partition plate divides the space within the housing in the first direction, forming a first space where the heat dissipation unit is located, and a second space. A communication opening is provided that connects the first space and the second space and extends in the second direction, such that the base ends of the plurality of heat dissipation fins are exposed to the second space, An air intake port is formed on the end face of the housing in a direction opposite to the third direction so as to communicate with the first space, An exhaust port is formed on the end face of the housing in a direction opposite to the second direction so as to communicate with the second space, It has, The light irradiation device is characterized in that the partition plate consists of a pair of plates arranged to sandwich the heat dissipation section from the first direction, and two second spaces are formed within the housing, flanking the first space.

2. A light irradiation device is positioned downstream in the first direction of a recording head that applies ink to a printing medium being transported in a first direction, and cures the ink on the printing medium, A light source unit comprising a substrate defined by a second direction perpendicular to the first direction and the first direction, and a plurality of light sources arranged in a line along the second direction on the surface of the substrate and emitting light in a third direction perpendicular to the first and second directions, wherein the light source unit irradiates the printing medium with line-shaped light, The heat dissipation portion has a plurality of heat dissipation fins erected at predetermined intervals along the second direction and is thermally coupled to the back side of the substrate, A housing that houses the heat dissipation unit, The enclosure contains a cooling fan that generates cooling air to cool the heat dissipation section, Equipped with, The aforementioned enclosure is A partition plate divides the space within the housing in the first direction, forming a first space where the heat dissipation unit is located, and a second space. A communication opening is provided that connects the first space and the second space and extends in the second direction, such that the base ends of the plurality of heat dissipation fins are exposed to the second space, An air intake port is formed on the end face of the housing in a direction opposite to the second direction so as to communicate with the second space, An exhaust port is formed on the end face of the housing in a direction opposite to the third direction so as to communicate with the first space, It has, The light irradiation device is characterized in that the partition plate consists of a pair of plates arranged to sandwich the heat dissipation section from the first direction, and two second spaces are formed within the housing, flanking the first space.

3. The light irradiation device according to claim 1 or 2, characterized in that the cooling fans are provided in N (where N is an integer of 2 or more) along the second direction so as to be opposite the plurality of heat dissipation fins in the third direction.

4. The light irradiation device according to any one of claims 1 to 3, characterized in that the second space is provided with partition plates arranged so as to divide the communication opening into a plurality of regions along the second direction, and for rectifying the cooling air passing through the communication opening.

5. The light irradiation device according to claim 4, referring to claim 3, characterized in that the partition plate is provided in (N-1) in such a way that the communication opening is divided into N regions corresponding to the N cooling fans.

6. The light irradiation device according to any one of claims 1 to 5, characterized in that it comprises a light-shielding unit connected to the housing so as to sandwich the transport path of the printing medium from the third direction, and which shields the light emitted from the light source so as not to leak to the outside.

7. The light irradiation device according to claim 6, characterized in that the light shielding unit has a hollow box-shaped main body portion with a light shielding surface formed at a position facing the light source portion.

8. The housing has a first opening that communicates with the second space at the end of the third end face in the second direction, The main body is, Opposite the first opening, there is a second opening that communicates with the internal space of the main body, A third opening is formed on the end face of the main body in the second direction so as to communicate with the internal space, The light irradiation device according to claim 7, characterized by having the following features.

9. The light irradiation device according to claim 8, characterized in that the internal space has a heat sink thermally bonded to the light-shielding surface.

10. The light irradiation device according to any one of claims 1 to 9, characterized in that it comprises a filter arranged to cover the air intake port and adsorbs ink mist.

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