Light irradiation device and printing apparatus

Abstract

The light irradiation device includes a light source, a heat dissipation member, a drive unit, and a rectangular parallelepiped-shaped housing. The housing accommodates the light source, the heat dissipation member, and the drive unit. The housing has a first outer surface, a second outer surface on a side opposite to the first outer surface, a third outer surface, a fourth outer surface on a side opposite to the third outer surface, a fifth outer surface, and a sixth outer surface on a side opposite to the fifth outer surface. The housing has a first opening, a second opening, and a third opening. The first opening opens at least in the first outer surface and allows light from the light source to pass therethrough. The second opening portion opens in a region on the first outer surface side of the third outer surface. The third opening portion opens in a region from the second outer surface to a portion of the third outer surface on the second outer surface side. The heat dissipation component comprises a base part and a plurality of protruding parts. Each of the protrusions protrudes from the base toward the second outer surface. The light source is located on the first outer surface side of the base. A plurality of gaps between the plurality of protrusions are adjacent to the second opening.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Japanese Application No. 2022 - 187077 (filed on November 24, 2022), and the entire disclosure of the Japanese application is incorporated herein by reference for reference purposes. Technical field

[0003] The present invention relates to a light irradiation device and a printing device. Background art

[0004] There are light irradiation devices that house a light source and a substrate for driving the light source in a housing (for example, refer to the descriptions of Patent Documents 1 and 2).

[0005] In this light irradiation device, as the light source, for example, a lamp or a light - emitting diode (LED) that emits light in a specific wavelength region such as ultraviolet or infrared light is used. This light irradiation device is applied, for example, to a printing device that uses a photocurable ink such as an ultraviolet - curable ink (also called UV ink) that cures (also called photocuring) by irradiation with ultraviolet light to print on a recording medium such as paper (also called a printed medium).

[0006] In recent years, various requirements for light irradiation devices have increased, such as miniaturization, simplification of the structure, reduction of failures, and improvement of cooling performance.

[0007] Prior art documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020 - 202346

[0010] Patent Document 2: Japanese Patent No. 6761148 Summary of the invention

[0011] A light irradiation device and a printing device are disclosed.

[0012] One aspect of a light irradiation device includes a light source, a heat dissipation member, a drive unit, and a rectangular parallelepiped-shaped housing. The light source includes a plurality of light-emitting elements. The heat dissipation member is thermally connected to the light source. The drive unit includes a drive circuit that drives the light source. The housing houses the light source, the heat dissipation member, and the drive unit. The housing has a first outer surface, a second outer surface, a third outer surface, a fourth outer surface, a fifth outer surface, and a sixth outer surface. The first outer surface is a rectangular surface. The second outer surface is a rectangular outer surface on the side opposite to the first outer surface in the housing. The third outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface. The fourth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface and is on the side opposite to the third outer surface. The fifth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface and connects the third outer surface and the fourth outer surface. The sixth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface, connects the third outer surface and the fourth outer surface, and is on the side opposite to the fifth outer surface. The housing has a first opening, a second opening, and a third opening. The first opening opens at least on the first outer surface and allows light from the light source to pass through. The second opening opens in a region on the first outer surface side in the third outer surface and connects the internal space of the housing and the external space. The third opening opens in a region of a portion from the second outer surface to the second outer surface side in the third outer surface and connects the internal space and the external space. The heat dissipation member includes a base portion and a plurality of protrusions. The base portion is located in a region on the first outer surface side in the internal space. The plurality of protrusions protrude from the base portion toward the second outer surface along a first direction from the first outer surface toward the second outer surface. The light source is located on the first outer surface side of the base portion. A plurality of gaps between the plurality of protrusions are adjacent to the second opening. The drive unit is located between the plurality of protrusions and the second outer surface in the internal space.

[0013] One aspect of a printing device includes the light irradiation device of the above aspect, a conveyance unit, and a printing unit. The conveyance unit conveys a printing medium irradiated with light from the first opening in a second direction, which is a direction from the third outer surface toward the fourth outer surface or from the fourth outer surface toward the third outer surface. The printing unit is located on a side in a third direction opposite to the second direction of the light irradiation device. The first outer surface is disposed downward. Description of the Drawings

[0014] Figure 1 This is a front view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0015] Figure 2 This is a left view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0016] Figure 3 This is a right view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0017] Figure 4 This is a top view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0018] Figure 5 This is a bottom view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0019] Figure 6 This is a perspective view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0020] Figure 7 This is a perspective view showing an example of the appearance of the light irradiation device according to the first embodiment.

[0021] Figure 8 This schematically shows a cross-sectional view of an example of a hypothetical cross-section of the light irradiation device viewed in the +Y direction at the position VIII-VIII in Figures 2 to 5 This is a cross-sectional view showing an example of the path of the air flow in an example of the light irradiation device according to the first embodiment.

[0022] Figure 9 This is a left view showing an example of the appearance of the heat dissipation member.

[0023] Figure 10 This is a front view showing an example of the appearance of the heat dissipation member.

[0024] Figure 11 This is a cross-sectional view schematically showing the path of the air flow in an example of the light irradiation device according to the first embodiment.

[0025] Figure 12 This is a graph showing an example of the relationship between the lighting time of the LED element, the temperature of the LED element, and the illuminance of the LED light obtained through experiments.

[0026] Figure 13 This is a left view showing an example of the appearance of the light irradiation device when the height of the second opening in the first direction is the first height.

[0027] Figure 14 This is a left view showing an example of the appearance of the light irradiation device when the height of the second opening in the first direction is the second height.

[0028] Figure 15 A left view showing an example of the appearance of a light irradiation device when the height of the second opening in the first direction is the third height.

[0029] Figure 16 A diagram showing an example of simulation results of the relationship between the height of the second opening and the temperature reached by the LED element when the LED element is lit.

[0030] Figure 17 A diagram showing a schematic structure of an example of a printing device according to the first embodiment.

[0031] Figure 18 A top view showing an example of the form of four types of inks attached to the upper surface of the printing medium.

[0032] Figure 19 A front view showing an example of a light irradiation device in a state fixed to a fixed portion of a printing device.

[0033] Figure 20 A right view showing an example of the appearance of a light irradiation device according to another example of the first embodiment.

[0034] Figure 21 A right view showing an example of the appearance of another example of a heat dissipation member.

[0035] Figure 22 A front view showing an example of the appearance of another example of a heat dissipation member.

[0036] Figure 23 A front view showing an example of another light irradiation device in a state fixed to a fixed portion of a printing device. Detailed Description of the Invention

[0037] There is a light irradiation device that houses a light source and a substrate for driving the light source in a housing. In this light irradiation device, as the light source, for example, a lamp or a light-emitting diode (LED) that emits light in a specific wavelength region such as ultraviolet or infrared is used.

[0038] This light irradiation device can be applied, for example, to a printing device that prints on a printing medium such as paper using a photocurable ink such as a UV ink that cures (photocures) by irradiation with ultraviolet light. In this printing device, for example, a form in which the light irradiation device irradiates ultraviolet light onto dot-like UV ink formed on the printing medium by an inkjet method or the like is considered.

[0039] However, in the above-described light irradiation device, heat is generated in the light source and the electronic components on the substrate when light is emitted. Therefore, for example, it is considered to use a heat dissipation member (also referred to as a heat sink) and a cooling fan to cool the light source and the electronic components.

[0040] However, for example, when a cooling fan is provided, it may lead to an increase in the size of the light irradiation device and a complication of the structure. In addition, for example, there is also a possibility of failure of the cooling fan that is rotationally driven. Further, for example, in a printing device, when turbulence occurs in the forced air flow due to the cooling fan, it may affect the ejection of UV ink onto the printing medium based on an inkjet method or the like and the landing of droplets of the UV ink on the printing medium.

[0041] Therefore, regarding the light irradiation device, there is room for improvement in achieving miniaturization, simplification of the structure, reduction of failures, and improvement of cooling performance while taking these factors into account.

[0042] Thus, the inventors of the present invention have created a technology for the light irradiation device that can achieve miniaturization, simplification of the structure, reduction of failures, and improvement of cooling performance while taking these factors into account.

[0043] Regarding this, hereinafter, the first embodiment and various examples will be described with reference to the drawings.

[0044] In the drawings, the same reference numerals are assigned to portions having the same or similar structures and functions, and repeated descriptions are omitted in the following description. Various structures are schematically shown in the drawings. In Figures 1 to 11 , Figures 13 to 15 and Figures 17 to 23 right-handed XYZ coordinate systems are respectively marked. In this XYZ coordinate system, the direction along the light emission direction (also referred to as the emission direction) of the light irradiation device 1 is set as the -Z direction, the first direction along the direction opposite to the emission direction is set as the +Z direction, the second direction along the thickness direction of the light irradiation device 1 is set as the +X direction, and the direction along the width direction of the light irradiation device 1 is set as the +Y direction. Here, in the following description, the second direction is set as the +X direction, but the second direction may also be set as the -X direction. It should be noted that the terms indicating directions such as "up", "down", "left", and "right" used in the description of the present invention are used only for the purpose of clarity of explanation and are not used for the purpose of limiting the structure and operation principle of the light irradiation device 1 and the printing device 100.

[0045] <1. First Embodiment>

[0046] <1-1. Structure of Light Irradiation Device>

[0047] The light irradiation device 1 is a device that irradiates light onto an object (also referred to as the irradiated object). The light irradiation device 1 of the present invention is of a type (also referred to as fanless type) that does not have a cooling fan (air supply section) for cooling the light source 11 and the like. Here, the fanless type light irradiation device includes a light irradiation device that does not have a fan (air supply section) inside the housing 14, a light irradiation device that does not have a fan (air supply section) in contact with the outside of the housing 14, and a light irradiation device that does not have a fan (air supply section) at the opening of the housing 14. In other words, the fanless type light irradiation device can be a light irradiation device that does not have a fan (air supply section) in any one of the inside of the housing 14, the position in contact with the outside of the housing 14, and the opening of the housing 14. The light irradiation device 1 can, for example, irradiate light in a specific wavelength region onto an object.

[0048] Figure 1 It is a front view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 2 It is a left view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 3 It is a right view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 4 It is a top view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 5 It is a bottom view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 6 It is a perspective view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 7 It is a perspective view showing an example of the appearance of the light irradiation device 1 of the first embodiment. Figure 8 It schematically shows at Figures 2 to 5 A cross-sectional view showing an example of a hypothetical cross-section of the light irradiation device 1 viewed in the +Y direction at the position VIII-VIII. Figure 9 It is a left view showing an example of the appearance of the heat dissipation member 12. Figure 10 It is a front view showing an example of the appearance of the heat dissipation member 12. In Figure 1 In order to show the positions of the second opening 140b, the third opening 140c, and the light source 11 respectively, the positions of the outer edges of the second opening 140b, the third opening 140c, and the light source 11 are schematically shown by thin dashed lines as hidden lines. More specifically, in Figure 1 In, the positions of the outer edges of the slit hole portion SL1 in the third opening 140c and the substrate 111 and the light emitting element 112 in the light source 11 are schematically shown by thin dashed lines as hidden lines.

[0049] As Figures 1 to 8As shown, the light irradiation device 1 includes a light source 11, a heat dissipation member (also referred to as a heat sink) 12, a drive unit 13, and a housing 14. The light source 11 includes a plurality of light emitting elements 112. The heat dissipation member 12 is thermally connected to the light source 11. The drive unit 13 includes a circuit (also referred to as a drive circuit) 132 that drives the light source 11. The housing 14 has a rectangular parallelepiped shape and houses the light source 11, the heat dissipation member 12, and the drive unit 13. In Figures 1 to 8 the example of, the light irradiation device 1 includes an optical system 16 and a connector 17.

[0050] <<Housing 14>>

[0051] The housing 14 forms the outer shape of the light irradiation device 1. The housing 14 has a rectangular first outer surface 14a, a rectangular second outer surface 14b, a rectangular third outer surface 14c, a rectangular fourth outer surface 14d, a rectangular fifth outer surface 14e, and a rectangular sixth outer surface 14f. The second outer surface 14b is the outer surface on the side opposite to the first outer surface 14a in the housing 14. The third outer surface 14c is the outer surface that connects the first outer surface 14a and the second outer surface 14b in the housing 14. The fourth outer surface 14d is the outer surface on the side opposite to the third outer surface 14c in the housing 14. The fourth outer surface 14d connects the first outer surface 14a and the second outer surface 14b. The fifth outer surface 14e is the outer surface that connects the first outer surface 14a and the second outer surface 14b and connects the third outer surface 14c and the fourth outer surface 14d in the housing 14. The sixth outer surface 14f is the outer surface on the side opposite to the fifth outer surface 14e in the housing 14. The sixth outer surface 14f connects the first outer surface 14a and the second outer surface 14b and connects the third outer surface 14c and the fourth outer surface 14d.

[0052] The first outer surface 14a has, for example, a pair of long sides (also referred to as the first long sides) respectively along the +Y direction and a pair of short sides (also referred to as the first short sides) respectively along the +X direction. In Figures 1 to 8 the example of, the first outer surface 14a faces the -Z direction. From another perspective, the first outer surface 14a is arranged along a virtual plane parallel to the XY plane.

[0053] The second outer surface 14b has, for example, a pair of long sides (also referred to as the second long sides) respectively along the +Y direction and a pair of short sides (also referred to as the second short sides) respectively along the +X direction. In Figures 1 to 8 the example of, the second outer surface 14b faces the +Z direction. From another perspective, the second outer surface 14b is arranged along a virtual plane parallel to the XY plane.

[0054] The first outer surface 14a and the second outer surface 14b may also have, for example, a plane-symmetrical relationship with respect to a hypothetical plane (also referred to as the first symmetry plane) along a hypothetical plane parallel to the XY plane. From another perspective, for example, the length of the first long side may be the same as the length of the second long side, and the length of the first short side may be the same as the length of the second short side.

[0055] The third outer surface 14c has, for example, two sides (also referred to as the first sides) that face each other and extend along the +Z direction respectively, and two sides (also referred to as the second sides) that face each other and extend along the +Y direction respectively. In Figures 1 to 8 the example, the third outer surface 14c faces the -X direction. From another perspective, the third outer surface 14c is arranged along a hypothetical plane parallel to the YZ plane. One of the two second sides on the -Z direction side may be the same side as one of the first long sides on the -X direction side of the pair of first long sides, or may be arranged along the one first long side. One of the two second sides on the +Z direction side may be the same side as one of the second long sides on the -X direction side of the pair of second long sides, or may be arranged along the one second long side.

[0056] The fourth outer surface 14d has, for example, two sides (also referred to as the third sides) that face each other and extend along the +Z direction respectively, and two sides (also referred to as the fourth sides) that face each other and extend along the +Y direction respectively. In Figures 1 to 8 the example, the fourth outer surface 14d faces the +X direction. From another perspective, the fourth outer surface 14d is arranged along a hypothetical plane parallel to the YZ plane. One of the two fourth sides on the -Z direction side may be the same side as one of the first long sides on the +X direction side of the pair of first long sides, or may be arranged along the one first long side. One of the two fourth sides on the +Z direction side may be the same side as one of the second long sides on the +X direction side of the pair of second long sides, or may be arranged along the one second long side.

[0057] The third outer surface 14c and the fourth outer surface 14d may also have, for example, a plane-symmetrical relationship with respect to a hypothetical plane (also referred to as the second symmetry plane) along a hypothetical plane parallel to the YZ plane. From another perspective, for example, the length of the first side may be the same as the length of the third side, and the length of the second side may be the same as the length of the fourth side.

[0058] The fifth outer surface 14e has, for example, a pair of long sides (also referred to as the third long sides) extending along the +Z direction respectively, and a pair of short sides (also referred to as the third short sides) extending along the +X direction respectively. In Figures 1 to 8In the example, the fifth outer surface 14e faces the -Y direction. From another perspective, the fifth outer surface 14e is arranged along a virtual plane parallel to the XZ plane. One of the pair of third long sides on the -X direction side can be the same side as one of the two first sides on the -Y direction side, or can be arranged along this one first side. One of the pair of third long sides on the +X direction side can be the same side as one of the two third sides on the -Y direction side, or can be arranged along this one third side. One of the pair of third short sides on the -Z direction side can be the same side as one of the pair of first short sides on the -Y direction side, or can be arranged along this one first short side. One of the pair of third short sides on the +Z direction side can be the same side as one of the pair of second short sides on the -Y direction side, or can be arranged along this one second short side.

[0059] The sixth outer surface 14f has, for example, a pair of long sides (also referred to as the fourth long sides) respectively along the +Z direction and a pair of short sides (also referred to as the fourth short sides) respectively along the +X direction. In Figures 1 to 8 the example, the sixth outer surface 14f faces the +Y direction. From another perspective, the sixth outer surface 14f is arranged along a virtual plane parallel to the XZ plane. One of the pair of fourth long sides on the -X direction side can be the same side as one of the two first sides on the +Y direction side, or can be arranged along this one first side. One of the pair of fourth long sides on the +X direction side can be the same side as one of the two third sides on the +Y direction side, or can be arranged along this one third side. One of the pair of fourth short sides on the -Z direction side can be the same side as one of the pair of first short sides on the +Y direction side, or can be arranged along this one first short side. One of the pair of fourth short sides on the +Z direction side can be the same side as one of the pair of second short sides on the +Y direction side, or can be arranged along this one second short side.

[0060] The fifth outer surface 14e and the sixth outer surface 14f can, for example, have a face-symmetric relationship with respect to a virtual plane (also referred to as the third symmetry plane) along a virtual plane parallel to the XZ plane. From another perspective, for example, it can be that the length of the third long side is the same as the length of the fourth long side, and the length of the third short side is the same as the length of the fourth short side.

[0061] Here, the length of each of the first short side of the first outer surface 14a, the second short side of the second outer surface 14b, the third short side of the fifth outer surface 14e, and the fourth short side of the sixth outer surface 14f (also referred to as the first length) is, for example, equivalent to the thickness of the housing 14. The length of each of the first long side of the first outer surface 14a, the second long side of the second outer surface 14b, the second side of the third outer surface 14c, and the fourth side of the fourth outer surface 14d (also referred to as the second length) is, for example, equivalent to the width of the housing 14. The length of each of the first side of the third outer surface 14c, the third side of the fourth outer surface 14d, the third long side of the fifth outer surface 14e, and the fourth long side of the sixth outer surface 14f (also referred to as the third length) is, for example, equivalent to the height of the housing 14.

[0062] The outer shape of the housing 14 is a thin rectangular parallelepiped shape. The dimensions of the housing 14 can be appropriately set according to the specifications and uses of the light irradiation device 1 and the like. For example, the first length (equivalent to the thickness of the housing 14) of each of the first short side of the first outer surface 14a, the second short side of the second outer surface 14b, the third short side of the fifth outer surface 14e, and the fourth short side of the sixth outer surface 14f can be set in a range of about 20 millimeters (mm) to 40 mm. For example, the second length (equivalent to the width of the housing 14) of each of the first long side of the first outer surface 14a, the second long side of the second outer surface 14b, the second side of the third outer surface 14c, and the fourth side of the fourth outer surface 14d can be set in a range of about 80 mm to 120 mm. For example, the third length (equivalent to the height of the housing 14) of each of the first side of the third outer surface 14c, the third side of the fourth outer surface 14d, the third long side of the fifth outer surface 14e, and the fourth long side of the sixth outer surface 14f can be set in a range of about 120 mm to 250 mm. Here, as long as the size relationship of "first length < second length < third length" is satisfied, the first length, the second length, and the third length can also be set to values different from the above numerical ranges.

[0063] Here, for example, the outer shape of the housing 14 does not need to be strictly a rectangular parallelepiped and can be a thin rectangular parallelepiped shape. The housing 14 has, for example, portions of eight vertices (also referred to as vertex portions) respectively formed by three of the first outer surface 14a, the second outer surface 14b, the third outer surface 14c, the fourth outer surface 14d, the fifth outer surface 14e, and the sixth outer surface 14f. The housing 14 has, for example, portions of twelve edges (also referred to as edge portions) respectively formed by two of the first outer surface 14a, the second outer surface 14b, the third outer surface 14c, the fourth outer surface 14d, the fifth outer surface 14e, and the sixth outer surface 14f. One or more of the vertex portions among the eight vertex portions can be set as rounded curved surfaces or chamfered inclined surfaces. For example, regarding the vertex portion, the chamfered inclined surface can be a surface that is inclined with respect to the three outer surfaces surrounding the vertex portion in a form that is obtuse with respect to all of the three outer surfaces. One or more of the edge portions among the twelve edge portions can be set as rounded curved surfaces or chamfered inclined surfaces. For example, regarding the edge portion, the chamfered inclined surface can be a surface that is inclined with respect to the two outer surfaces sandwiching the edge portion in a form that is obtuse with respect to both of the two outer surfaces. Here, for example, the first length can also be the distance between the third outer surface 14c and the fourth outer surface 14d, the second length can also be the distance between the fifth outer surface 14e and the sixth outer surface 14f, and the third length can also be the distance between the first outer surface 14a and the second outer surface 14b.

[0064] In addition, from another perspective, the housing 14 includes a first wall portion 141, a second wall portion 142, a third wall portion 143, a fourth wall portion 144, a fifth wall portion 145, and a sixth wall portion 146.

[0065] The first wall portion 141 has the first outer surface 14a in the housing 14. In other words, the first wall portion 141 is the portion on the first outer surface 14a side in the housing 14. In Figures 1 to 8 the example, the first wall portion 141 is the portion on the -Z direction side in the housing 14. The first wall portion 141 can be, for example, a flat plate-like portion along a virtual plane parallel to the XY plane. The first wall portion 141 is not limited to a flat plate-like portion and can, for example, also have one or more concavities and convexities, etc.

[0066] The second wall portion 142 has the second outer surface 14b in the housing 14. In other words, the second wall portion 142 is the portion on the second outer surface 14b side in the housing 14. In Figures 1 to 8 the example, the second wall portion 142 is the portion on the +Z direction side in the housing 14. The second wall portion 142 can be, for example, a flat plate-like portion along a virtual plane parallel to the XY plane. The second wall portion 142 is not limited to a flat plate-like portion and can, for example, also have one or more concavities and convexities, etc.

[0067] The third wall portion 143 has the third outer surface 14c of the housing 14. In other words, the third wall portion 143 is the portion on the side of the third outer surface 14c in the housing 14. In Figures 1 to 8 the example of, the third wall portion 143 is the portion on the -X direction side in the housing 14. The third wall portion 143 can be, for example, a flat plate-like portion along a virtual plane parallel to the YZ plane. The third wall portion 143 is not limited to the flat plate-like portion, and can have, for example, one or more concavities and convexities.

[0068] The fourth wall portion 144 has the fourth outer surface 14d of the housing 14. In other words, the fourth wall portion 144 is the portion on the side of the fourth outer surface 14d in the housing 14. In Figures 1 to 8 the example of, the fourth wall portion 144 is the portion on the +X direction side in the housing 14. The fourth wall portion 144 can be, for example, a flat plate-like portion along a virtual plane parallel to the YZ plane. The fourth wall portion 144 is not limited to the flat plate-like portion, and can have, for example, one or more concavities and convexities.

[0069] The fifth wall portion 145 has the fifth outer surface 14e of the housing 14. In other words, the fifth wall portion 145 is the portion on the side of the fifth outer surface 14e in the housing 14. In Figures 1 to 8 the example of, the fifth wall portion 145 is the portion on the -Y direction side in the housing 14. The fifth wall portion 145 can be, for example, a flat plate-like portion along a virtual plane parallel to the XZ plane. The fifth wall portion 145 is not limited to the flat plate-like portion, and can have, for example, one or more concavities and convexities.

[0070] The sixth wall portion 146 has the sixth outer surface 14f of the housing 14. In other words, the sixth wall portion 146 is the portion on the side of the sixth outer surface 14f in the housing 14. In Figures 1 to 8 the example of, the sixth wall portion 146 is the portion on the +Y direction side in the housing 14. The sixth wall portion 146 can be, for example, a flat plate-like portion along a virtual plane parallel to the XZ plane. The sixth wall portion 146 is not limited to the flat plate-like portion, and can have, for example, one or more concavities and convexities.

[0071] The housing 14 has an internal space (also referred to as the inner space) 14i surrounded by, for example, a first wall portion 141, a second wall portion 142, a third wall portion 143, a fourth wall portion 144, a fifth wall portion 145, and a sixth wall portion 146. In other words, the first wall portion 141 is on the -Z direction side of the internal space 14i. The second wall portion 142 is on the +Z direction side of the internal space 14i. The third wall portion 143 is on the -X direction side of the internal space 14i. The fourth wall portion 144 is on the +X direction side of the internal space 14i. The fifth wall portion 145 is on the -Y direction side of the internal space 14i. The sixth wall portion 146 is on the +Y direction side of the internal space 14i.

[0072] The housing 14 has a first opening 140a, a second opening 140b, and a third opening 140c.

[0073] The first opening 140a opens at least on the first outer surface 14a. The first opening 140a is an opening (also referred to as the irradiation port) for allowing light from the light source 11 to pass through. In the first embodiment, the first opening 140a penetrates the first wall portion 141 in the thickness direction of the first wall portion 141.

[0074] In Figures 1 to 8 the example of, the first opening 140a is an elongated opening arranged along the +Y direction. The first opening 140a is an elongated rectangular opening having a length direction along the +Y direction when viewed in a plane in the +Z direction. More specifically, the first opening 140a opens in a region from the end portion on the -Z direction side of the fifth outer surface 14e through the first outer surface 14a to the end portion on the -Z direction side of the sixth outer surface 14f. From another perspective, the first opening 140a penetrates the first wall portion 141 in the -Z direction. More specifically, the first opening 140a is in a state of penetrating the housing 14 in a region from the end portion on the -Z direction side of the fifth wall portion 145 through the first wall portion 141 to the end portion on the -Z direction side of the sixth wall portion 146.

[0075] Here, the length of the first opening 140a in the thickness direction (also referred to as the thickness direction) of the housing 14 can be set, for example, to about 20% to 70% of the first length corresponding to the thickness of the housing 14. For example, if the first length of the housing 14 is about 30 mm, the length of the first opening 140a in the thickness direction of the housing 14 can be set to about 8 mm. In Figures 1 to 8In the example, the thickness direction of the shell 14 is along the +X direction which is the second direction. The length of the first opening 140a in the width direction (also referred to as the width direction) of the shell 14 can be set to be the same as the second length corresponding to the width of the shell 14. For example, if the second length of the shell 14 is about 120 mm, the length of the first opening 140a in the width direction of the shell 14 can be set to be about 120 mm. Figures 1 to 8 In the example, the width direction of the housing 14 is the direction along the +Y direction. If the first opening 140a is opened over the entire first outer surface 14a in the width direction of the housing 14, the light irradiation device 1 can be miniaturized. In this case, for example, when a plurality of light irradiation devices 1 are arranged in the width direction of the light irradiation device 1, the distribution of the amount of light emitted from the plurality of light irradiation devices 1 can be more uniform in the width direction of the light irradiation device 1. However, the length of the first opening 140a in the width direction of the housing 14 is not limited to a length that is the same as the second length corresponding to the width of the housing 14. The shape of the first opening 140a can be set to an elongated rectangular shape like the first outer surface 14a, but is not limited thereto. For example, the shape of the first opening 140a can be appropriately set according to the shape of the area in the object (irradiated object) to which light is irradiated by the light irradiation device 1, etc. The shape of the first opening 140a may be, for example, a wavy shape elongated in the width direction of the housing 14, an oblong shape elongated in the width direction of the housing 14, or a shape in which a plurality of circular portions are arranged in the width direction of the housing 14. In addition, the size of the first opening 140a when the first outer surface 14a is viewed in a plan view may be appropriately set within the size range of the first outer surface 14a according to the size of the region in the object (irradiated object) to which the light irradiation device 1 irradiates light, etc. The first opening 140a may be opened in the center portion of the first outer surface 14a including the center point of the first outer surface 14a, or may be opened in the first outer surface 14a at a position offset from the center point of the first outer surface 14a.

[0076] The second opening portion 140b opens in the area on the first outer surface 14a side of the third outer surface 14c. Here, for example, it is assumed that the third outer surface 14c is virtually equally divided into N1 areas (N1 is a natural number greater than 2) in the +Z direction as the first direction. In this case, the area on the first outer surface 14a side of the third outer surface 14c can be included in the area located closest to the first outer surface 14a side among the N1 areas. The natural number N1 can be appropriately set according to the design of the air intake and exhaust and heat dissipation in the light irradiation device 1. The natural number N1 can be, for example, 2, 3, or 4.

[0077] The second opening portion 140b connects the internal space 14i of the shell 14 with the space (also referred to as the external space) 14o outside the shell 14. The second opening portion 140b, for example, has a function as an opening portion (also referred to as an air intake port) for sucking air from the external space 14o of the shell 14 into the internal space 14i. In the first embodiment, the second opening portion 140b penetrates the third wall portion 143 in the thickness direction of the third wall portion 143. The shell 14 has, for example, an end face (also referred to as the first end face) 143e constituting an edge on the first outer surface 14a side of the second opening portion 140b. More specifically, for example, the third wall portion 143 has a first end face 143e constituting an edge on the first outer surface 14a side of the second opening portion 140b.

[0078] exist Figures 1 to 8 In the example, the second opening portion 140b is a rectangular opening portion. More specifically, the second opening portion 140b is a rectangular opening portion having a pair of long sides (also referred to as the fifth long side) along the +Y direction and a pair of short sides (also referred to as the fifth short side) along the +Z direction. From another point of view, the second opening portion 140b penetrates the third wall portion 143 along the +X direction. The length of the fifth long side of the second opening portion 140b can be less than the length of the first long side in the width direction of the shell 14. The length of the fifth short side of the second opening portion 140b can be appropriately set according to the size of the heat dissipation component 12 and the design of the air intake and exhaust and heat dissipation in the light irradiation device 1.

[0079] The third opening portion 140c opens in the area from the second outer surface 14b to the portion of the third outer surface 14c on the second outer surface 14b side. Here, for example, consider a case where the third outer surface 14c is hypothetically divided into N2 (N2 is a natural number greater than 4) equal parts in the +Z direction which is the first direction. In this case, the portion of the third outer surface 14c on the second outer surface 14b side can be included in the portion of the N2 portions that is located closest to the second outer surface 14b side. The natural number N2 can be appropriately set according to the design of the air intake and exhaust and heat dissipation in the light irradiation device 1. The natural number N2 can be, for example, 4, 5, 6, 7, 8, 9, or 10.

[0080] The third opening 140c connects the internal space 14i of the housing 14 to the external space 14o of the housing 14. The third opening 140c functions as an opening (also referred to as an exhaust port) for exhausting air from the internal space 14i of the housing 14 to the external space 14o.

[0081] Here, the third opening 140c may have a plurality of hole portions that open in a region of a portion on the second outer surface 14b side in the direction from the second outer surface 14b to the third outer surface 14c. In Figures 1 to 8 the example, the plurality of hole portions are a plurality of slit-shaped hole portions (also referred to as slit holes) SL1. Each slit hole SL1 opens in a region of a portion on the second outer surface 14b side in the direction from the second outer surface 14b to the third outer surface 14c. From another perspective, each slit hole SL1 penetrates the second wall portion 142 and the third wall portion 143 in a portion from the second wall portion 142 to the third wall portion 143. In other words, a portion from the second wall portion 142 to the third wall portion 143 has a plurality of slit holes SL1 for discharging air from the internal space 14i of the housing 14 to the external space 14o. In this case, the plurality of slit holes SL1 function as exhaust ports.

[0082] The plurality of slit holes SL1 apply a first specified number of slit holes SL1. The first specified number is 2 or more. In other words, the plurality of slit holes SL1 apply 2 or more slit holes SL1. The plurality of slit holes SL1 may be arranged, for example, in the width direction of the housing 14 from the fifth outer surface 14e toward the sixth outer surface 14f. The plurality of slit holes SL1 may be arranged, for example, at a first pitch in the width direction of the housing 14. Each of the plurality of slit holes SL1 has a shape in which a first elongated portion and a second elongated portion are connected in an L shape. The first elongated portion opens on the second outer surface 14b and extends along the thickness direction of the housing 14 from the fourth outer surface 14d toward the third outer surface 14c, and the second elongated portion opens on the third outer surface 14c and extends along the height direction of the housing 14 from the second outer surface 14b toward the first outer surface 14a. Thus, for example, if the third opening 140c is composed of a plurality of slit holes SL1, intrusion of foreign matter from the external space 14o of the housing 14 into the internal space 14i can be reduced. Foreign matter may include, for example, dust, dirt, metal parts, and tools. Here, the plurality of hole portions in the third opening 140c may also be, for example, a plurality of hole portions arranged in a mesh shape.

[0083] In Figure 2 、 Figure 4 with, Figures 6 to 8In the example, the first specified number of slit holes SL1 are arranged in the +Y direction along the width direction of the housing 14. Each slit hole SL1 has a shape in which a first elongated portion and a second elongated portion are connected in an L shape. The first elongated portion opens on the second outer surface 14b and extends along the -X direction, and the second elongated portion opens on the third outer surface 14c and extends along the -Z direction. The first specified number, the first pitch, and the width and length of each slit hole SL1 among the plurality of slit holes SL1 can be appropriately set according to, for example, the design of intake and exhaust and heat dissipation in the light irradiation device 1 and the designability of the appearance, etc.

[0084] The first specified number can be, for example, around 28. In other words, about 28 slit holes SL1 can be used for the plurality of slit holes SL1. The first pitch can be, for example, around 4 mm. The width of each of the plurality of slit holes SL1 can be around 2 mm. The length of the first elongated portion (also referred to as the fourth length) of each slit hole SL1 in the -X direction can be, for example, around 5 mm. The length of the second elongated portion (also referred to as the fifth length) of each slit hole SL1 in the -Z direction can be, for example, around 15 mm. The first specified number is not limited to 28, and can be, for example, other numbers such as around 20 to 40. In other words, for the plurality of slit holes SL1, the number of slit holes SL1 other than 28, such as around 20 to 40, can also be used. The first pitch is not limited to around 4 mm, and can be set to other lengths of around 2 mm to 6 mm according to the first specified number, for example. The length of the first elongated portion (the fourth length) of each slit hole SL1 in the -X direction is not limited to around 5 mm, and can be set to other lengths of around 3 mm to 10 mm according to, for example, the thickness of the housing 14 and the position of the connector 17. The length of the second elongated portion (the fifth length) of each slit hole SL1 in the -Z direction is not limited to around 15 mm, and can be set to other lengths of around 10 mm to 20 mm according to, for example, the size of the housing 14. The width of the slit hole SL1, the length of the first elongated portion (the fourth length), and the length of the second elongated portion (the fifth length) can be the same or different among the plurality of slit holes SL1.

[0085] The arrangement, shape, size, etc. of the second opening 140b and the third opening 140c in the housing 14 can be appropriately set according to, for example, the design of intake and exhaust and heat dissipation in the light irradiation device 1.

[0086] The material of the housing 14 can be, for example, a metal such as aluminum or a plastic.

[0087] The housing 14 can be formed, for example, by connecting multiple components to each other. The multiple components can be connected via the heat dissipation component 12 by being fixed to the heat dissipation component 12, or can be directly connected. The multiple components constituting the housing 14 can also include, for example, a first component, a second component, and a third component. The first component can be, for example, a component including the portion of the third wall portion 143, the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146 on the side of the first wall portion 141 relative to the heat dissipation component 12, and the first wall portion 141. The second component can be, for example, a component including the portion of the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146 from the area along the heat dissipation component 12 to the area along the second wall portion 142. The third component can be, for example, a component including the portion of the third wall portion 143 from the area along the heat dissipation component 12 to the area of the second wall portion 142, and the second wall portion 142.

[0088] The fixation of the multiple components to the heat dissipation component 12 can be achieved, for example, by fastening connection using screws or the like. The fixation of the multiple components to the heat dissipation component 12 is not limited to fastening connection using screws or the like, and can also be achieved in other forms such as bonding, joining, riveting, and fitting. In addition, the direct connection between the multiple components can be achieved in various forms such as fastening connection using screws or the like, bonding, joining, riveting, and fitting.

[0089] The first component, the second component, and the third component can each, for example, also have portions (also referred to as connection portions) for connecting to each other. For example, the third component can include: a plate-shaped first connection portion that extends along a part of the fifth wall portion 145 from the first side on the fifth wall portion 145 side of the third wall portion 143; and a plate-shaped second connection portion that extends along a part of the sixth wall portion 146 from the first side on the sixth wall portion 146 side of the third wall portion 143. In this case, for example, by fastening and connecting the first connection portion to the fifth wall portion 145 using screw fastening or the like and fastening and connecting the second connection portion to the sixth wall portion 146 using screw fastening or the like, the second component and the third component can be connected. The first component can be manufactured, for example, by metal casting processing or by resin molding. The second component and the third component can each be manufactured, for example, by various processing of a metal plate-shaped component or by resin molding. The various processing can include, for example, one or more of stamping, bending, blanking, and cutting processing.

[0090] <<Heat dissipation component 12>>

[0091] The heat dissipation member 12 is a member for dissipating the heat generated by the light source 11 when it emits light. The heat dissipation member 12 is thermally connected to the light source 11. The material of the heat dissipation member 12 is, for example, a metal having excellent thermal conductivity, such as aluminum or copper. The form in which the heat dissipation member 12 is thermally connected to the light source 11 includes not only a form in which the heat dissipation member 12 is directly connected to the light source 11, but also a form in which the heat dissipation member 12 is indirectly connected to the light source 11 via one or more members having excellent thermal conductivity.

[0092] The heat dissipation member 12 includes a base portion 121 and a plurality of protrusions 122 .

[0093] The base 121 is located in the area on the side of the first outer surface 14a in the internal space 14i of the shell 14. For example, consider a case where the internal space 14i is hypothetically divided into N3 (N3 is a natural number greater than 4) equal areas in the +Z direction as the first direction. In this case, the area on the side of the first outer surface 14a in the internal space 14i of the shell 14 can be included in the area located closest to the first outer surface 14a among the N3 areas. The natural number N3 can be appropriately set according to the design of heat dissipation and air intake and exhaust in the light irradiation device 1. The natural number N3 can be, for example, 4, 5, or 6. The base 121 can have, for example, a block shape or a plate shape.

[0094] The base 121 may also be in contact with the inner surface of the housing 14, for example. In this case, for example, the third wall portion 143 may be fixed to the base 121, the fourth wall portion 144 may be fixed to the base 121, the fifth wall portion 145 may be fixed to the base 121, and the sixth wall portion 146 may be fixed to the base 121. The third wall portion 143 has, for example, a surface on the inner space 14i side (also referred to as the first inner surface) Iw1. The fourth wall portion 144 has, for example, a surface on the inner space 14i side (also referred to as the second inner surface) Iw2. Here, for example, the base 121 may be in contact with the first inner surface Iw1 of the third wall portion 143, or may be in contact with the second inner surface Iw2 of the fourth wall portion 144. In other words, the base 121 may also be in contact with the first inner surface Iw1, which is the inner surface on the side of the third outer surface 14c located in the inner space 14i, of the housing 14, or may be in contact with the second inner surface Iw2, which is the inner surface on the side of the fourth outer surface 14d located in the inner space 14i, of the housing 14. In addition, the fifth wall portion 145 has, for example, a surface on the inner space 14i side (also referred to as the third inner surface). The sixth wall portion 146 has, for example, a surface on the inner space 14i side (also referred to as the fourth inner surface). Here, for example, the base 121 may also be in contact with the third inner surface of the fifth wall portion 145, or may be in contact with the fourth surface of the sixth wall portion 146. In other words, the base 121 may also be in contact with the third inner surface, which is the inner surface on the side of the fifth outer surface 14e located in the inner space 14i, of the housing 14, or may be in contact with the fourth inner surface, which is the inner surface on the side of the sixth outer surface 14f located in the inner space 14i, of the housing 14.

[0095] The base 121 may also be close to the inner surface of the housing 14, for example. In this case, for example, a heat conductive grease such as a so-called thermal grease or heat dissipation grease may be interposed to make the base 121 closely adhere to the inner surface of the housing 14. Here, for example, the base 121 may be close to the first inner surface Iw1 of the third wall portion 143, or may be close to the second inner surface Iw2 of the fourth wall portion 144. In addition, for example, the base 121 may also be close to the third inner surface of the fifth wall portion 145, or may be close to the fourth inner surface of the sixth wall portion 146.

[0096] In Figures 8 to 10In the example, the base 121 has a rectangular parallelepiped shape, and the outer surface of the rectangular parallelepiped is along a virtual plane parallel to the first outer surface 14a and the second outer surface 14b. More specifically, the base 121 may have a rectangular parallelepiped shape along a virtual plane parallel to the XY plane. The base 121 may have a surface (also referred to as the first surface) 121u located on the side of the second outer surface 14b and facing the second outer surface 14b side. The first surface 121u may be, for example, a surface facing the +Z direction. In other words, the first surface 121u may be a surface along a virtual plane parallel to the XY plane. The first surface 121u may be coplanar with the first end surface 143e of the edge on the first outer surface 14a side that forms the second opening 140b in the housing 14, or may be offset from the first end surface 143e toward the first outer surface 14a side or the second outer surface 14b side by a certain amount. From another perspective, most or all of the base 121 may also be located at a position closer to the first outer surface 14a than the second opening 140b. In addition, the base 121 has a surface (also referred to as the second surface) 121b located on the first outer surface 14a side. The second surface 121b may be, for example, a surface facing the -Z direction. In other words, the second surface 121b may be a surface along a virtual plane parallel to the XY plane.

[0097] The plurality of protrusions 122 protrude from the base 121 toward the second outer surface 14b along a first direction from the first outer surface 14a toward the second outer surface 14b. There are a plurality of gaps 12s between the plurality of protrusions 122. The plurality of gaps 12s between the plurality of protrusions 122 are adjacent to the second opening 140b. In other words, the plurality of gaps 12s are connected to the external space 14o via the second opening 140b. Thus, air can flow into the plurality of gaps 12s from the external space 14o of the housing 14 via the second opening 140b.

[0098] The plurality of protrusions 122 may each have, for example, a thin plate-like shape. According to the heat dissipation member 12, as air flows through the plurality of gaps 12s between the plurality of protrusions 122, the heat transferred from the light source 11 to the heat dissipation member 12 dissipates into the air, and the light source 11 can be cooled. The plurality of protrusions 122 apply the second specified number of protrusions 122. The second specified number is 2 or more. In other words, the plurality of protrusions 122 apply 2 or more protrusions 122. The plurality of protrusions 122 may be arranged, for example, in the width direction of the housing 14 from the fifth outer surface 14e toward the sixth outer surface 14f. The plurality of protrusions 122 may be arranged at a second pitch in the width direction of the housing 14, for example. Each of the plurality of protrusions 122 may be, for example, a thin plate-like portion (also referred to as a fin) along a virtual plane parallel to the fifth outer surface 14e. Each of the plurality of protrusions 122 may have a thickness in the width direction of the housing 14 from the fifth outer surface 14e toward the sixth outer surface 14f. Each of the plurality of protrusions 122 may have a specified length (also referred to as the sixth length) in the first direction from the first outer surface 14a toward the second outer surface 14b, for example.

[0099] In Figure 2 and Figures 6 to 10 the example of, the second specified number of protrusions 122 each protrude from the first surface 121u of the base 121 in the +Z direction as the first direction. The second specified number of protrusions 122 are each thin plate-like portions (fins) along a virtual plane parallel to the XZ plane and have a thickness along the +Y direction as the width direction of the housing 14. The second specified number of protrusions 122 each have a specified length (the sixth length) in the +Z direction as the first direction. The plurality of protrusions 122 are arranged at a second pitch in the +Y direction as the width direction of the housing 14. The second specified number and the second pitch of the plurality of protrusions 122, and the thickness and the sixth length of each protrusion 122 can be appropriately set according to, for example, the intake and exhaust and heat dissipation design in the light irradiation device 1.

[0100] The second specified quantity can be applied as about 19, for example. In other words, the plurality of protrusions 122 can be applied as 19 pieces of protrusions 122. The second spacing can be applied as about 6 mm, for example. The thickness of each of the plurality of protrusions 122 can be applied as about 2 mm, for example. The sixth length of each of the plurality of protrusions 122 can be applied as about 28 mm, for example. The second specified quantity is not limited to 19, and can be other quantities such as about 10 to 30, for example. In other words, the plurality of protrusions 122 can be applied as protrusions 122 with a number of pieces different from 19, such as about 10 to 30 pieces. The second spacing is not limited to 6 mm, and can be other lengths such as about 4 mm to 11 mm according to the second specified quantity, for example. The thickness of the protrusion 122 is not limited to 2 mm, and can be other thicknesses such as about 1 mm to 4 mm, for example. The sixth length of the protrusion 122 is not limited to 28 mm, and can be other lengths such as about 20 mm to 40 mm, for example. The thickness and the sixth length of the protrusion 122 can be the same or different among the plurality of protrusions 122.

[0101] Two adjacent protrusions 122 among the plurality of protrusions 122 are arranged with a gap 12s therebetween. Here, for example, if all of the plurality of gaps 12s are connected to the external space 14o via the second opening 140b, the amount of air flowing into the plurality of gaps 12s from the external space 14o per unit time via the second opening 140b can be increased. In Figure 2 and Figures 6 to 10 In the example of, if the plurality of protrusions 122 are 19 fins, there are 18 gaps 12s between the 19 fins. And, for example, if all of the 18 gaps 12s as the plurality of gaps 12s are connected to the external space 14o via the second opening 140b, the amount of air flowing into the plurality of gaps 12s from the external space 14o per unit time via the second opening 140b can be increased.

[0102] The heat dissipation member 12 can also have a structure in which the surface area is increased by forming a plurality of grooves in a rectangular parallelepiped metal block by cutting or the like, or can have a structure in which a plurality of metal thin plates are mounted on the metal block or the flat plate.

[0103] <<Light source 11>>

[0104] The light source 11 is located on the side of the first outer surface 14a of the base 121 of the heat dissipation member 12. The light source 11 faces the first opening 140a that opens in the first outer surface 14a. The light source 11 has, for example, a substrate 111 and a plurality of light-emitting elements 112. In Figure 5 In the example of, the light source 11 has 3 substrates 111 and 18 light-emitting elements 112. The plurality of light-emitting elements 112 are in a state of being disposed on the substrate 111.

[0105] The substrate 111 is a substrate (also referred to as a substrate for arranging light-emitting elements) on which a plurality of light-emitting elements 112 are arranged. The substrate 111 is, for example, a plate-shaped substrate made of ceramics (also referred to as a ceramic wiring substrate). On the surface and inside of the substrate 111, there are wiring conductors that electrically connect the inside and outside of the substrate 111. The material of the wiring conductors is, for example, a conductive material such as tungsten, molybdenum, manganese, or copper. If the substrate 111 is a ceramic wiring substrate, the material of the base material of the ceramic wiring substrate is insulating ceramics. Therefore, the ceramic wiring substrate has heat resistance to the heat generated by the light source 11 on which a plurality of light-emitting elements 112 are integrated.

[0106] The substrate 111 is located on the side of the first outer surface 14a of the base portion 121 of the heat dissipation member 12. The substrate 111 has, for example, a plate-shaped shape along the base portion 121. The substrate 111 can be fixed to the base portion 121, for example. The fixing of the substrate 111 to the base portion 121 can be achieved by, for example, screw fastening. A heat-conductive grease can also be interposed between the base portion 121 and the substrate 111 to make the base portion 121 and the substrate 111 in close contact. Thereby, the thermal connection between the light source 11 and the heat dissipation member 12 can be improved. As a result, the efficiency of heat dissipation from the light source 11 via the heat dissipation member 12 can be improved. Here, the substrate 111 can also be fixed to the base portion 121 via a member made of a metal with excellent thermal conductivity, etc.

[0107] Each of the plurality of light-emitting elements 112 is, for example, a light-emitting diode (LED) element. Regarding the type of the light-emitting element 112, it can be appropriately selected according to the wavelength of the light emitted from the light-emitting element 112. For example, for an LED element, a gallium nitride (GaN)-based LED can be used as an LED that emits ultraviolet light, and a gallium arsenide (GaAs)-based LED can be used as an LED that emits infrared light. For example, the plurality of light-emitting elements 112 can be arranged in a row on the substrate 111, or can be arranged in a matrix shape with multiple rows.

[0108] In Figure 5 this example, the substrate 111 has a flat plate-shaped shape along a virtual plane parallel to the XY plane. The substrate 111 is fixed on the second surface 121b of the base portion 121. Three substrates 111 are arranged adjacent to each other along the +Y direction. Above the three substrates 111, 18 light-emitting elements 112 are arranged in a row along the +Y direction. More specifically, six light-emitting elements 112 are arranged in a row along the +Y direction on the surfaces of the three substrates 111 facing the -Z direction.

[0109] <<Drive unit 13>>

[0110] The drive unit 13 is located between the plurality of protrusions 122 and the second outer surface 14b in the internal space 14i of the housing 14.

[0111] The driving unit 13 is electrically connected to the light source 11. The driving unit 13 includes, for example, a wiring substrate 131 and a driving circuit 132.

[0112] The wiring substrate 131 is, for example, a printed circuit board or the like. The wiring substrate 131 is fixed to the inner surface side of the housing 14, for example. Here, for example, the wiring substrate 131 can be fixed to the inner surface side of the housing 14 by screw fastening or the like via a base, a support, or a spacer disposed on the inner surface of the housing 14. Alternatively, for example, the wiring substrate 131 can be fixed to the inner surface side of the housing 14 by fitting the wiring substrate 131 into the unevenness disposed on the inner surface of the housing 14. In Figure 8 the example, the wiring substrate 131 is fixed to the inner surface side of the second wall portion 142 of the housing 14. The wiring substrate 131 can be, for example, a flat substrate disposed along a virtual plane parallel to the YZ plane.

[0113] The driving circuit 132 includes, for example, one or more electronic components 132i. In Figure 8 the figure, the region where the one or more electronic components 132i are located is shown as an elongated rectangle with hatching using a right upper diagonal line. The one or more electronic components 132i are mounted on the wiring substrate 131. The driving circuit 132 can supply power to the light source 11 and control the light emission of the light source 11, for example. The driving unit 13 having the driving circuit 132 generates heat when the light source 11 is driven. Therefore, it is necessary to cool the driving unit 13 by appropriate heat dissipation. When the one or more electronic components 132i include a plurality of electronic components 132i, if the plurality of electronic components 132i are arranged in a non-dense manner, the temperature rise in the driving circuit 132 can be reduced.

[0114] Here, for example, when the one or more electronic components 132i include electronic components such as a power transistor that is likely to generate a large amount of heat, a heat sink can be installed in the driving unit 13 for the purpose of increasing the heat dissipation from the electronic components 132i. One or more structures such as a groove, a fin, and a wind guide plate can be disposed in a portion around the driving unit 13 on the inner surface of the housing 14 for the purpose of effectively bringing the air flow into contact with the portion that is likely to become high temperature in the driving unit 13.

[0115] The drive circuit 132 and the light source 11 can be electrically connected through various wiring components. More specifically, the drive circuit 132 and the plurality of light-emitting elements 112 can be electrically connected via various wiring components and the substrate 111, etc. Various wiring components can, for example, apply flexible printed circuit boards (Flexible Printed Circuits: FPC). The FPC can be connected to the drive circuit 132 via a board connector, for example. The position, shape, size, etc. of the various wiring components that electrically connect the drive circuit 132 and the light source 11 can be appropriately set according to the design of the appropriate air flow in the internal space 14i of the housing 14. For example, if the various wiring components are arranged in such a way that they do not pass through the space between the heat dissipation member 12 and the second wall portion 142 and between the drive portion 13 and the third wall portion 143 as much as possible, the decrease in the speed and flow rate of the air flow from the plurality of gaps 12s of the heat dissipation member 12 toward the third opening 140c can be reduced. Thereby, the decrease in the heat dissipation efficiency from the heat dissipation member 12 can be reduced. Here, the various wiring components can adopt a form that connects from the substrate 111 between the heat dissipation member 12 and the inner surface of the housing 14 and through a place slightly away from the heat dissipation member 12 to the drive circuit 132.

[0116] <<Optical system 16>>

[0117] The optical system 16 can adjust the optical path of the light emitted from the light source 11. The optical system 16 is, for example, located between the light source 11 and the first opening 140a or at the first opening 140a. The shape, size, etc. of the optical system 16 can be appropriately set according to specifications such as the size and shape of the irradiated light area in the object (the irradiated object) and the intensity of the light irradiated onto the object (the irradiated object). The optical system 16 applies various lenses, for example. In Figure 1 , Figure 5 , Figure 6 and Figure 8 example, as the optical system 16, a cylindrical rod lens having a central axis along the +Y direction is adopted. The optical system 16 can also apply various optical components such as a semi-cylindrical cylindrical lens or a flat transparent member different from the rod lens, for example. The material of the optical system 16 applies transparent glass or heat-resistant plastic, etc., for example. The optical system 16 can also include a reflection portion that reflects light, for example.

[0118] <<Connector 17>>

[0119] The connector 17 is a part that connects the plurality of wirings connected to the drive portion 13 and the plurality of wirings located outside the housing 14. The connector 17 is located on the side of the second outer surface 14b of the light irradiation device 1, for example. The light irradiation device 1 can have one connector 17 or two or more connectors 17. In Figures 1 to 8In the example, the light irradiation device 1 has two connectors 17. The plurality of wirings include, for example, a wiring for supplying power from the outside to the drive unit 13 (also referred to as a power line), and a wiring for receiving signals from the outside to the drive unit 13 and transmitting signals from the drive unit 13 to the outside (also referred to as a signal line). The supply of power from the outside of the light irradiation device 1 to the drive unit 13 and the exchange of control signals can be achieved via the connector 17.

[0120] <1-1-1. Air flow inside the housing>

[0121] Figure 11 It is a cross-sectional view schematically showing the path of the air flow in an example of the light irradiation device 1 of the first embodiment. Figure 11 The cross-sectional view of Figure 8 corresponds to the cross-sectional view of Figure 11 In Figure 11 the light irradiation device 1 is arranged with the first outer surface 14a facing downwards, and the path of the air flow generated when the light source 11 generates heat due to light emission is schematically shown by two curves and arrows drawn with a double-dot dash line. In

[0122] Here, for example, in a state where the first outer surface 14a is arranged facing downwards, the heat generated corresponding to the light emission of the plurality of light-emitting elements 112 dissipates into the internal space 14i of the housing 14 via the heat dissipation member 12. In this case, the air flowing into the plurality of gaps 12s between the plurality of protrusions 122 from the external space 14o through the second opening 140b is heated by the heat dissipated from the plurality of protrusions 122 and rises, generating a smooth air flow that is discharged to the external space 14o through the third opening 140c. At this time, due to the chimney effect, the air is discharged from the external space 14o to the external space 14o successively through the second opening 140b, the internal space 14i, and the third opening 140c. Through this air flow, the heat dissipation member 12 can be cooled.

[0123] In the first embodiment, when the first outer surface 14a is disposed downward, the third opening 140c is disposed at the upper part from the upward second outer surface 14b to the third outer surface 14c. Therefore, for example, even if there is a connector 17 or the like on the second outer surface 14b side, the size of the opening required for exhausting air from the internal space 14i to the external space 14o of the third opening 140c can be ensured, and the distance between the plurality of protrusions 122 and the third opening 140c becomes longer. As a result, a smooth upward air flow is generated from the plurality of gaps 12s between the plurality of protrusions 122 toward the third opening 140c, and the speed of the upward air flow can increase due to the chimney effect. As a result, the heat dissipation member 12 can be efficiently cooled. Therefore, even if a cooling fan is not provided in the light irradiation device 1, the heat dissipation member 12 can be efficiently cooled. Therefore, it is possible to achieve miniaturization, simplification of the structure, reduction of failures, and improvement of cooling performance in the light irradiation device 1 at the same time.

[0124] Here, for example, the drive unit 13 may be located in a region of the internal space 14i that is closer to the fourth outer surface 14d than the third outer surface 14c. In other words, for example, the drive unit 13 may be located in a region of the internal space 14i that is closer to the fourth wall portion 144 than the third wall portion 143. As a result, a decrease in the speed and flow rate of the air flowing from the plurality of gaps 12s of the heat dissipation member 12 toward the third opening 140c can be reduced. And, for example, one or more electronic components 132i may be located between the second opening 140b and the third opening 140c in the first direction from the first outer surface 14a toward the second outer surface 14b. And, for example, the drive unit 13 may be disposed in a state where one or more electronic components 132i face the third outer surface 14c side. In other words, for example, the drive unit 13 may be disposed in a state where one or more electronic components 132i face the third wall portion 143 side. From another perspective, for example, the surface of the wiring board 131 on which one or more electronic components 132i are mounted may face the third wall portion 143 side. In Figure 8 and Figure 11 the example of, the surface of the wiring board 131 on which one or more electronic components 132i are mounted may face the -X direction.

[0125] If such a structure is adopted, when the first outer surface 14a is disposed downward, when heat generated corresponding to the light emission of the plurality of light-emitting elements 112 dissipates into the internal space 14i of the housing 14 via the heat dissipation member 12, the flow path of the air rising from the plurality of gaps 12s toward the third opening 140c can include a path along one or more electronic components 132i. Thereby, the flow of air in contact with one or more electronic components 132i can be increased, and the cooling efficiency of the drive circuit 132 can be improved. As a result, the operation stability of the drive circuit 132 can be improved, and thus the reliability of the light irradiation device 1 can be improved.

[0126] Here, for example, if the base portion 121 of the heat dissipation member 12 is in contact with the inner surface of the housing 14, the cooling efficiency of the heat dissipation member 12 can be improved by heat transfer from the heat dissipation member 12 to the housing 14.

[0127] Here, for example, it may also be that a portion on the base portion 121 side in the plurality of gaps 12s is adjacent to the second opening 140b, and in the first direction from the first outer surface 14a toward the second outer surface 14b, the length of the second opening 140b is equal to or less than the length of the plurality of protrusions 122. If such a structure is adopted, when the first outer surface 14a is disposed downward, when heat generated corresponding to the light emission of the plurality of light-emitting elements 112 dissipates into the internal space 14i of the housing 14 via the heat dissipation member 12, the air flowing into the internal space 14i of the housing 14 from the external space 14o via the second opening 140b can pass through a larger area of the plurality of gaps 12s. In addition, the distance between the second opening 140b and the third opening 140c can be increased. Thereby, the speed of the upward air flow caused by the chimney effect from the plurality of gaps 12s between the plurality of protrusions 122 toward the third opening 140c can be increased. As a result, the heat dissipation member 12 can be efficiently cooled. Here, the size of the portion on the base portion 121 side in the plurality of gaps 12s can be appropriately set according to the size, air intake and exhaust, and heat dissipation design in the light irradiation device 1. The portion on the base portion 121 side in the plurality of gaps 12s may, for example, also include a region in contact with the first surface 121u of the base portion 121 in the plurality of gaps 12s, or may include a region close to the first surface 121u of the base portion 121 in the plurality of gaps 12s.

[0128] Here, for example, the portion on the second outer surface 14b side of the plurality of protrusions 122 may also be in contact with the first inner surface Iw1 on the third outer surface 14c side of the inner space 14i in the housing 14. If this structure is adopted, the heat dissipation member 12 can be cooled more efficiently by heat transfer from the plurality of protrusions 122 to the housing 14. Here, the size of the portion on the second outer surface 14b side of the plurality of protrusions 122 can be appropriately set according to the design of the size, air intake and exhaust, and heat dissipation in the light irradiation device 1. Here, for example, it is assumed that the plurality of protrusions 122 are virtually equally divided into N4 regions (N4 is a natural number greater than or equal to 2) in the +Z direction as the first direction. In this case, the portion on the second outer surface 14b side of the plurality of protrusions 122 may be included in, for example, the region located closest to the second outer surface 14b side among the N4 regions. The natural number N4 can be appropriately set according to the design of the air intake and exhaust, and heat dissipation in the light irradiation device 1. The natural number N4 may be, for example, 2, 3, 4, or any number greater than 5.

[0129] Here, it is assumed that the length of the second opening 140b in the first direction is less than the length of the protrusion 122 and the portion of the second outer surface 14b side of the plurality of protrusions 122 is in contact with the first inner surface 1w1. In this case, the plurality of slit-shaped portions in contact with the second opening 140b in the plurality of gaps 12s function as a substantial air intake port for sucking air from the external space 14o to the internal space 14i. Here, for example, the total size of the plurality of slit hole portions SL1 functioning as an exhaust port can be set to a range of about 1 to 2 times the size of the substantial air intake port. In this case, a smooth flow of air discharged from the external space 14o to the external space 14o through the second opening 140b, the internal space 14i, and the third opening 140c in sequence can be efficiently generated.

[0130] For example, consider the following structure: the length of the second opening 140b in the first direction is 12mm, the plurality of protrusions 122 are 19 fins, the pitch (second pitch) of the plurality of protrusions 122 is 6mm, and the thickness of the plurality of protrusions 122 is 2mm. In this structure, the actual area of ​​the air intake port (also referred to as the effective area of ​​the air intake port) is 864mm. 2(=12 mm × 4 mm × 18). And, for example, consider the following structure: The multiple slit hole portions SL1 in the third opening portion 140c are 28 L-shaped slits, the pitch (first pitch) of the multiple slit hole portions SL1 is 4 mm, and for each slit hole portion SL1, the width is 2 mm, the length of the first elongated portion (fourth length) is 5 mm, and the length of the second elongated portion (fifth length) is 15 mm. In this structure, the area of the exhaust port of the third opening portion 140c (also referred to as the exhaust port area) is 1120 mm 2 (= (5 mm + 15 mm) × 2 mm × 28). In this case, the exhaust port area, which is the size of the multiple slit hole portions SL1 having the function of the exhaust port, is larger than the effective area of the suction port, which is the size of the substantial suction port, and the exhaust port area is about 1.3 times the effective area of the suction port.

[0131] <1-1-2. Temperature Drift in Light-Emitting Elements>

[0132] Light-emitting elements such as LED elements generate heat corresponding to light emission when lit, and the illuminance of the light irradiated to an object (the irradiated object) may vary due to temperature changes. For example, in an LED element, a phenomenon occurs in which the illuminance decreases as the temperature rises (also referred to as temperature drift). The lighting of the light-emitting element refers to the case where the light-emitting element is in a light-emitting state (also referred to as a light-emitting state). In the present invention, the lighting of the light-emitting element is synonymous with the light emission of the light-emitting element.

[0133] Then, the following experiment was conducted: In a state where the light irradiation device 1 with the first outer surface 14a facing upward was fixed by a resin-made jig, while light was generated upward from the light source 11, the temperatures of the multiple light-emitting elements 112 and the illuminance of the light from the light source 11 were measured.

[0134] Here, as the multiple light-emitting elements 112, 18 LED elements having a peak wavelength of the emitted light (also referred to as LED light) of 395 nanometers (nm) were used. On three substrates 111 arranged adjacent to each other in the width direction of the housing 14, the 18 LED elements were arranged in a row at a configuration interval of 6.5 mm. Each LED element was made to emit light with a forward current of 0.35 amperes (A). The illuminance of the light from the light source 11 was measured using an illuminometer (UVPF-A2 manufactured by EYE GRAPHICS Co., Ltd.) fixed to a resin-made jig. The 18 LED elements were photographed downward using an infrared camera (InfraRed Camera R500 manufactured by Japan Aviation Electronics Industry Co., Ltd.) fixed to a resin-made jig, and the temperatures of the multiple light-emitting elements 112 were measured. The temperature of the room where the experiment was conducted was set to 25 degrees as the reference temperature.

[0135] Figure 12This is a diagram showing an example of the relationship between the lighting time of an LED element obtained through experiments, the temperature of the LED element, and the illuminance of the LED light emitted from the LED element. The lighting time of the LED element refers to the continuous lighting time of the LED element starting from the moment when the LED element starts to emit light. In Figure 12 the relationship between the lighting time of the LED element and the temperature of the LED element is represented by a curve of multiple blackened circles, and the relationship between the lighting time of the LED element and the illuminance of the LED light is represented by a curve of multiple hollow circles. In Figure 12 the illuminance of the LED light sets the illuminance at the time point when the lighting of multiple LED elements starts as the initial value, and is represented by a percentage that is the ratio relative to this initial value.

[0136] As Figure 12 shown, as time elapses from the start of lighting of multiple LED elements, the temperature of the LED element rises, and it is confirmed that there is a temperature drift in which the illuminance of the LED light decreases as the temperature of the LED element rises.

[0137] Here, the decrease rate of the illuminance of the LED light due to temperature drift is set as D1 [percentage (%)]. The decrease rate of the illuminance of the LED light corresponding to a 1-degree (°C) temperature rise of the LED element is set as d0 [% / °C]. The temperature reached by the LED element (also referred to as the reached temperature of the LED element) is set as T1 [°C]. The initial temperature of the LED element (also referred to as the initial temperature of the LED element) is set as T0 [°C]. In this case, the temperature drift can be approximately expressed by the following formula (1).

[0138] D1 [%] = d0 [% / °C] × (T1 [°C] - T0 [°C]) (1).

[0139] Regarding the temperature drift related to the LED element used in the above experiment, d0 [percentage (%)] is approximately calculated as 0.18 [% / °C]. In addition, the initial temperature T0 [°C] of the LED element is 25 [°C] which is the above-mentioned reference temperature. Therefore, the temperature drift [%] of the LED element used in the above experiment can be approximately expressed by the following formula (2).

[0140] D1 [%] = 0.18 [% / °C] × (T1 [°C] - 25 [°C]) (2).

[0141] Here, if the temperature rise of the plurality of LED elements in the light irradiation device 1 is set below a certain level, the reduction rate of the illuminance of the light irradiated from the light irradiation device 1 to the object (irradiated object) can also be made below a certain level. Thus, the illuminance of the light emitted from the light irradiation device 1 can be made stable. Regarding the temperature drift D1 [%], for example, there is a case where the target is set to 5% or less. In this case, according to Equation (2), it can be calculated that if the reached temperature T1 [°C] of the LED element is 53 °C or less, the temperature drift D1 [%] can be made 5% or less. In other words, regarding the structure used in the above experiment, in order to make the temperature drift D1 [%] 5% or less, it is necessary to set the reached temperature of the LED element to 53 °C or less.

[0142] <1-1-3. Relationship between the height of the second opening and the reached temperature of the light-emitting element>

[0143] It is assumed that the light irradiation device 1 is used with the first outer surface 14a facing downward. In this case, regarding the second opening 140b, by adjusting the height H, which is the length in the +Z direction as the first direction, the reached temperature of the plurality of light-emitting elements 112 can be decreased when the plurality of light-emitting elements 112 emit light.

[0144] Here, a simulation performed on the following relationship will be described. This relationship is the relationship between the height H of the second opening 140b in the +Z direction as the first direction and the temperature reached by the plurality of light-emitting elements 112 due to the heat generated by the combined light emission of the plurality of light-emitting elements 112.

[0145] <<Simulation conditions>>

[0146] The simulation is performed using the thermal fluid analysis software (SOLIDWORKS Flow Simulation) manufactured by the Institute of Structural Planning. In the simulation, the following conditions are used as the conditions of the light irradiation device 1.

[0147] Regarding the attitude of the light irradiation device 1, the first outer surface 14a is set to face downward.

[0148] Regarding the housing 14, the first length, which is the thickness of the housing 14, is set to 30 mm, the second length, which is the width of the housing 14, is set to 120 mm, and the third length, which is the height of the housing 14, is set to 134.8 mm. The corners of the housing 14 are set to rounded surfaces with a radius of curvature of approximately 0.5 mm. The housing 14 is configured to include a first member, a second member, and a third member that are respectively fixed to the heat dissipation member 12 by screw fastening. The first member is the portion of the housing 14 on the side of the first outer surface 14a closer to the heat dissipation member 12. The first member is a member having a length of 120 mm in the width direction of the housing 14, a length of 30 mm in the thickness direction of the housing 14, and a length of 14.8 mm in the height direction of the housing 14. The second portion is a member including a portion from the region along the heat dissipation member 12 to the region along the second wall portion 142 in the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146. The third member is a member including a portion from the region along the heat dissipation member 12 to the region along the second wall portion 142 in the third wall portion 143 and the second wall portion 142. The second member and the third member are respectively members formed by bending a plate material with a thickness of 1 mm. The material of the housing 14 is aluminum with a thermal conductivity of 204 [watts per meter per kelvin (W / (m×K))]. The shape of the first opening 140a when observing the first outer surface 14a in a plan view is a shape having a length of approximately 8.14 mm in the thickness direction of the housing 14 and a length of 120 mm in the width direction of the housing 14, which is the same as the width of the housing 14. The shape of the first opening 140a when observing the fifth outer surface 14e in a plan view is a shape having a first circular portion and a first trapezoidal portion having an upper base connected to the portion on the side of the first outer surface 14a in the first circular portion. The diameter of the first circular portion is set to 10.2 mm. Regarding the first trapezoidal portion, the length of the upper base is set to 8.14 mm, and the length of the lower base is set to 13 mm. The shape of the first opening 140a when observing the sixth outer surface 14f in a plan view is a shape having a second circular portion and a second trapezoidal portion having an upper base connected to the portion on the side of the first outer surface 14a in the second circular portion. The diameter of the second circular portion is set to 10.2 mm. Regarding the second trapezoidal portion, the length of the upper base is set to 8.14 mm, and the length of the lower base is set to 13 mm. The center points of the first circular portion and the second circular portion are each set to points located at a distance of 10.3 mm from the heat dissipation member 12 and at the center in the thickness direction of the housing 14.

[0149] Regarding the optical system 16, a glass rod lens having a length of 120 mm and a diameter of 10 mm along the central axis in the width direction of the housing 14 is provided. The rod lens is in a state of being fitted into both the first circular portion and the second circular portion in the first opening 140a.

[0150] Regarding the plurality of light-emitting elements 112, 18 LED elements arranged in a row at a pitch of 6.5 mm are provided on three substrates 111 arranged side by side in the width direction of the housing 14. The heat generation amount of the 18 LED elements is 11 watts (W).

[0151] Regarding the three substrates 111, the outer shape of each of the three substrates 111 is a plate shape having a length of 39 mm in the width direction of the housing 14, a length of 15 mm in the thickness direction of the housing 14, and a length (also referred to as thickness) of 2 mm in the height direction of the housing 14. The material of the three substrates 111 is copper having a thermal conductivity of 372 [W / (m×K)]. The three substrates 111 are arranged in a state of being adjacent to each other in the width direction of the housing 14.

[0152] Regarding the heat dissipation member 12, the shape of the base portion 121 of the heat dissipation member 12 is a rectangular parallelepiped shape having a length of 118 mm in the width direction of the housing 14, a length of 28 mm in the thickness direction of the housing 14, and a length (also referred to as thickness) of 8 mm in the height direction of the housing. The plurality of protrusions 122 of the heat dissipation member 12 are 19 fins arranged at a pitch of 6 mm in the width direction of the housing 14. The shape of each fin is a thin plate shape having a length (also referred to as thickness) of 2 mm in the width direction of the housing 14, a length of 28 mm in the thickness direction of the housing 14, and a length (also referred to as height) of 28 mm in the height direction of the housing. The material of the heat dissipation member 12 is aluminum having a thermal conductivity of 204 [W / (m×K)].

[0153] Regarding the drive unit 13, the shape of the drive unit 13 is a thin plate shape having a length of 80 mm in the width direction of the housing 14, a length (also referred to as thickness) of 2 mm in the thickness direction of the housing 14, and a length of 100 mm in the height direction of the housing. The material of the wiring substrate 131 of the drive unit 13 is epoxy glass having a thermal conductivity of 0.38 [W / (m×K)]. The drive unit 13 is arranged in parallel with the fourth wall portion 144 at a position separated from the fourth wall portion 144 by 9 mm.

[0154] Regarding the second opening 140b, the shape in a plan view is a rectangular shape. The first end face 143e forming the edge on the first outer surface 14a side of the second opening 140b and the first surface 121u on the second outer surface 14b side of the base 121 of the heat dissipation member 12 are set to be coplanar. The length (also referred to as the width) of the second opening 140b in the width direction of the housing 14 is set to 110 mm. The length (height) H of the second opening 140b in the height direction of the housing 14 is set to 9 heights of 0 mm, 4 mm, 8 mm, 12 mm, 16 mm, 20 mm, 24 mm, 28 mm, and 32 mm. Figure 13 FIG. is a left view showing an example of the appearance of the light irradiation device 1 when the height H of the second opening 140b in the +Z direction as the first direction is the first height H1. Figure 14 FIG. is a left view showing an example of the appearance of the light irradiation device 1 when the height H of the second opening 140b in the +Z direction as the first direction is the second height H2. Figure 15 FIG. is a left view showing an example of the appearance of the light irradiation device 1 when the height H of the second opening 140b in the +Z direction as the first direction is the third height H3. The second height H2 is larger than the first height H1, and the third height H3 is larger than the second height H2. Figure 13 The first height H1 of the example of Figure 14 The second height H2 of the example of Figure 15 The third height H3 of the example of is 32 mm. In Figure 13 and Figure 14 FIG., the outer edges of the portions of the plurality of protrusions 122 located on the back surface of the third wall portion 143 are schematically shown by thin dashed lines as hidden lines.

[0155] Regarding the third opening 140c, it is set to have a shape with 28 slit hole portions SL1 at intervals of 4 mm in the width direction of the housing 14. Each slit hole portion SL1 is set to be an L-shaped slit hole portion having the same shape and size. The shape of the slit hole portion SL1 in a plan view of the third outer surface 14c is a rectangular shape with a length in the height direction of the housing 14 of 15 mm and a length in the width direction of the housing 14 of 2 mm. The shape of the slit hole portion SL1 in a plan view of the second outer surface 14b is a rectangular shape with a length in the thickness direction of the housing 14 of 5 mm and a length in the width direction of the housing 14 of 2 mm.

[0156] <<Simulation Results>>

[0157] Figure 16 FIG. is a diagram showing an example of the simulation results of the relationship between the height of the second opening 140b and the temperature reached by the LED element when the LED element is lit. InFigure 16 Among them, the relationship between the height of the second opening portion 140b and the temperature reached by the LED element is shown by a curve of a plurality of blackened circles.

[0158] As Figure 16 shown, simulation results are obtained that when the height of the second opening portion 140b is 12 mm to 28 mm, the temperature reached by the LED element becomes 53°C or less with the above-mentioned temperature drift D1 of 5% or less.

[0159] Therefore, for example, it is confirmed that when the length (height) of the protrusion 122 of the heat dissipation member 12 in the height direction of the housing 14 is 28 mm, if the height of the second opening portion 140b is more than half and the same as or less than that, the temperature drift D1 can be 5% or less. More specifically, for example, it is confirmed that when the length (height) of the protrusion 122 of the heat dissipation member 12 in the height direction of the housing 14 is 28 mm, if the height of the second opening portion 140b is 43% (≈12 / 28×100 [%]) or more and the same as or less than that, the temperature drift D1 can be 5% or less.

[0160] Therefore, for example, when the portion on the base 121 side in the plurality of gaps 12s is adjacent to the second opening portion 140b, if the length (height) H of the second opening portion 140b in the first direction from the first outer surface 14a toward the second outer surface 14b is more than half and less than the length of the plurality of protrusions 122, the cooling performance in the light irradiation device 1 can be improved. More specifically, if in the first direction, the length (height) H of the second opening portion 140b is 43% or more and less than the length of the plurality of protrusions 122, the cooling performance in the light irradiation device 1 can be improved. Here, the first surface 121u of the base 121 can be coplanar with the first end surface 143e forming the edge of the first outer surface 14a side of the second opening portion 140b in the housing 14, or can be offset a little from the first end surface 143e toward the first outer surface 14a side or the second outer surface 14b side. It should be noted that for the length (height) H of the second opening portion 140b in the first direction to be more than half of the length of the plurality of protrusions 122, it is not necessary for the length (height) H of the second opening portion 140b in the first direction to be exactly more than 1 / 2 of the length of the plurality of protrusions 122. Here, for more than half of the length of the plurality of protrusions 122, it is only necessary to be recognized as more than half with a margin that is generally allowable in terms of size. As Figure 16As shown, when the length (height) H of the second opening 140b in the first direction becomes about 1 / 3 of the length of the plurality of protrusions 122, it is not certain that the temperature reached by the LED element becomes 53°C or lower, and there is a tendency that it is difficult to say that the cooling performance of the light irradiation device 1 can be improved. Therefore, the fact that the length (height) H of the second opening 140b in the first direction is more than half of the length of the plurality of protrusions 122 is an expression based on the recognition that there is a margin with respect to this tendency. A structure in which the length (height) H of the second opening 140b in the first direction is more than half of the length of the plurality of protrusions 122 can include, for example, a structure in which the length (height) H of the second opening 140b in the first direction is 43% or more of the length of the plurality of protrusions 122.

[0161] <1-2. Schematic structure of the printing device>

[0162] Figure 17 This is a diagram showing a schematic structure of an example of the printing device 100 according to the first embodiment.

[0163] As Figure 17 shown, the printing device 100 includes the above-described light irradiation device (also referred to as the first light irradiation device) 1, a conveyance unit 2, and a printing unit 3. In Figure 17 this example, the printing device 100 includes three first light irradiation devices 1, a conveyance unit 2, four printing units 3, another light irradiation device (also referred to as the second light irradiation device) 6, and a control unit (also referred to as a controller) 9. The three first light irradiation devices 1 include a first A light irradiation device 1a, a first B light irradiation device 1b, and a first C light irradiation device 1c. The four printing units 3 include a first printing unit 3a, a second printing unit 3b, a third printing unit 3c, and a fourth printing unit 3d.

[0164] <<Conveyance unit 2>>

[0165] The conveyance unit 2 conveys the printing medium 4 in a predetermined direction (also referred to as the second direction and the conveyance direction). The printing medium 4 is an object to be printed in the printing device 100. The printing medium 4 can be, for example, a sheet made of paper or resin, or a thin plate-like material made of resin, semiconductor, metal, or wood.

[0166] In Figure 17 this example, the conveyance unit 2 can convey the printing medium 4 arranged along a virtual plane parallel to the horizontal plane in the +X direction as the second direction. In other words, the conveyance direction is the +X direction. The width direction perpendicular to the conveyance direction of the printing medium 4 is the +Y direction. The thickness direction of the printing medium 4 is the +Z direction as the first direction. In Figure 17 this, the conveyance direction is shown by an arrow drawn with a thin solid line.

[0167] In Figure 17 example, above the printed medium 4 carried by the carrying unit 2, in the +X direction as the carrying direction, the first printing unit 3a, the first A light irradiation device 1a, the second printing unit 3b, the first B light irradiation device 1b, the third printing unit 3c, the first C light irradiation device 1c, the fourth printing unit 3d, and the second light irradiation device 6 are arranged in sequence.

[0168] As Figure 17 shown, for example, the carrying unit 2 may have a pair of carrying rollers 21 located on the upstream side of the printing device 100 and a pair of carrying rollers 22 located on the downstream side of the printing device 100. The pair of carrying rollers 21 hold the printed medium 4 by clamping it from above and below. The pair of carrying rollers 22 hold the printed medium 4 by clamping it from above and below. The printed medium 4 can be carried in the carrying direction by the rotation of the pair of carrying rollers 21 on the downstream side and the rotation of the pair of carrying rollers 22 on the upstream side. The rotation of each of the pair of carrying rollers 21 can be achieved by driving with an electric motor or the like. The rotation of each of the pair of carrying rollers 22 can be achieved by driving with an electric motor or the like.

[0169] The carrying unit 2 may also have, for example, a support portion that supports the printed medium 4 from below between the pair of carrying rollers 21 on the upstream side and the pair of carrying rollers 22 on the downstream side. The support portion may be, for example, a plurality of rollers (also referred to as support rollers) having a cylindrical or columnar shape. The plurality of support rollers may have axial directions respectively along a direction perpendicular to the carrying direction and are arranged in the carrying direction.

[0170] <<Printing Unit 3>>

[0171] The printing unit 3 can print on the printed medium 4. The printing unit 3 is located on the side in the direction opposite to the carrying direction (the second direction) (also referred to as the third direction) with respect to the first light irradiation device 1. The side in the third direction may also be referred to as the upstream side in the carrying direction. In other words, the printing unit 3 is arranged on the upstream side of the first light irradiation device 1 with respect to the carrying direction of the printed medium 4. In Figure 17 example, the third direction is the -X direction.

[0172] In Figure 17 example, the first printing unit 3a is located on the -X direction side as the third direction of the first A light irradiation device 1a. The second printing unit 3b is located on the -X direction side as the third direction of the first B light irradiation device 1b. The third printing unit 3c is located on the -X direction side as the third direction of the first C light irradiation device 1c.

[0173] The printing unit 3 uses, for example, an ink jet (IJ) head that ejects ink 5. The ink 5 is a photo-curable ink (also referred to as photo-curable ink) that is used as a photosensitive material. The photo-curable ink is an ink that cures (also referred to as photo-curing) in response to irradiation with light in a specific wavelength range. The photo-curable ink uses, for example, an ultraviolet-curable ink (also referred to as UV ink) that cures (photo-cures) in response to irradiation with ultraviolet light, which is light in a specific wavelength range.

[0174] The printing unit 3 can attach the ink 5 to the upper surface of the printing medium 4 that is conveyed by the conveying unit 2 by, for example, ejecting the ink 5 onto the upper surface of the printing medium 4. Here, the IJ head of the printing unit 3 can attach droplets of the ink 5 to the upper surface of the printing medium 4 by, for example, ejecting droplets of the ink 5 onto the upper surface of the printing medium 4 that is conveyed by the conveying unit 2. The printing unit 3 can attach the ink 5 to the upper surface of the printing medium 4 in a desired pattern, for example. The printing unit 3 can, for example, also attach the ink 5 to substantially the entire upper surface of the printing medium 4, or can attach the ink 5 to a part of the upper surface of the printing medium 4.

[0175] The first printing unit 3a can attach the first type of ink (also referred to as the first ink) 5a to the upper surface of the printing medium 4 that is conveyed by the conveying unit 2 by, for example, ejecting the first ink 5a onto the upper surface of the printing medium 4. The first ink 5a uses, for example, the ink of the first color. The first ink 5a can use the first UV ink (also referred to as the first UV ink) that is the ink of the first color. The first color can be, for example, cyan (C).

[0176] The second printing unit 3b can attach the second type of ink (also referred to as the second ink) 5b to the upper surface of the printing medium 4 that is conveyed by the conveying unit 2 by, for example, ejecting the second ink 5b onto the upper surface of the printing medium 4. The second ink 5b uses, for example, the ink of the second color. The second ink 5b can use the second UV ink (also referred to as the second UV ink) that is the ink of the second color. The second color can be, for example, magenta (M).

[0177] The third printing unit 3c can attach the third type of ink (also referred to as the third ink) 5c to the upper surface of the printing medium 4 that is conveyed by the conveying unit 2 by, for example, ejecting the third ink 5c onto the upper surface of the printing medium 4. The third ink 5c uses, for example, the ink of the third color. The third ink 5c can use the third UV ink (also referred to as the third UV ink) that is the ink of the third color. The third color can be, for example, yellow (Y).

[0178] The fourth printing unit 3d can cause the fourth type of ink (also referred to as the fourth ink) 5d to adhere to the upper surface of the printing medium 4 transported by the transport unit 2, for example, by ejecting the fourth ink 5d onto the upper surface of the printing medium 4. The fourth ink 5d applies the ink of the fourth color, for example. The fourth ink 5d can apply the fourth UV ink (also referred to as the fourth UV ink) as the ink of the fourth color. The fourth color can apply black (Black: K), for example.

[0179] Here, for example, the first color can also be any one of cyan, magenta, yellow, and black. For example, the second color can also be any one of cyan, magenta, yellow, and black that is different from the first color. For example, the third color can also be any one of cyan, magenta, yellow, and black that is different from the first color and the second color. For example, the fourth color can also be any one of cyan, magenta, yellow, and black that is different from the first color, the second color, and the third color.

[0180] Here, as the IJ head of the printing unit 3, a line-type IJ head can be applied, for example. The line-type IJ head has a plurality of ink ejection holes arranged in a line (linear shape). The line-type IJ head can eject the ink 5 from each of the plurality of ink ejection holes. The direction in which the plurality of ink ejection holes are arranged (also referred to as the arrangement direction) applies a direction that is orthogonal to the transport direction of the printing medium 4 transported by the transport unit 2 and parallel to the upper surface of the printing medium 4 transported by the transport unit 2. In other words, the arrangement direction of the plurality of ink ejection holes can apply the width direction perpendicular to the transport direction of the printing medium 4 transported by the transport unit 2. In the Figure 17 example, the arrangement direction of the plurality of ink ejection holes applies the +Y direction. With this structure, the ink 5 is ejected from the plurality of ink ejection holes of the line-type IJ head onto the printing medium 4 transported by the transport unit 2 in the transport direction, so that the ink 5 can cover the upper surface of the printing medium 4. As a result, the upper surface of the printing medium 4 can be printed by the printing unit 3.

[0181] As the IJ head of the printing unit 3, other types of IJ heads such as a serial-type IJ head different from the line-type IJ head can be applied, for example. The serial-type IJ head can move along the width direction of the printing medium 4. In this case, by alternately performing the printing on the upper surface of the printing medium 4 during the movement of the serial-type IJ head in the width direction of the printing medium 4 and the movement in the transport direction of the printing medium 4 by the transport unit 2, the upper surface of the printing medium 4 can be printed by the printing unit 3.

[0182] <<First light irradiation device 1>>

[0183] The first light irradiation device 1 can irradiate light from the first opening 140a onto the printing medium 4 being conveyed in the conveyance direction by the conveyance unit 2. The first light irradiation device 1 is located on the downstream side of the printing unit 3 in the conveyance direction in which the conveyance unit 2 conveys the printing medium 4. The first outer surface 14a of the first light irradiation device 1 is arranged facing downward.

[0184] As described above, regarding the first light irradiation device 1, even if a cooling fan is not provided, the cooling performance in the light irradiation device 1 can be improved. Therefore, the generation of disturbances in the forced air flow caused by the cooling fan or the like can be reduced. As a result, in the printing device 100, the influence of the disturbance of the air flow on the ejection of the ink 5 onto the upper surface of the printing medium 4 by the printing unit 3 and the landing of the droplets of the ink 5 on the upper surface of the printing medium 4 can be reduced. In addition, since the printing unit 3 and the first light irradiation device 1 can be arranged close to each other, miniaturization of the printing device 100 can be achieved.

[0185] In Figure 17 the example, the first light irradiation device 1 can irradiate the light from the first opening 140a of the downward-facing first outer surface 14a onto the upper surface of the printing medium 4. In Figure 17 it, the outer edge of the light from the first light irradiation device 1 toward the upper surface of the printing medium 4 is schematically shown by a one-dot chain line. When the ink 5 is a photo-curable ink, if the light irradiated from the first light irradiation device 1 onto the upper surface of the printing medium 4 is light in a specific wavelength region for causing the photo-curable ink to cure (photo-curing), the ink 5 attached to the upper surface of the printing medium 4 can be cured by the light from the first light irradiation device 1. For example, when the ink 5 is an ultraviolet-curable ink (UV ink), if the light irradiated from the first light irradiation device 1 onto the upper surface of the printing medium 4 is ultraviolet light as light in a specific wavelength region, the UV ink as the ink 5 attached to the upper surface of the printing medium 4 can be cured.

[0186] For example, when the first ink 5a is a photo-curable ink, the first A light irradiation device 1a can cure the first ink 5a attached to the upper surface of the printing medium 4 by irradiating light in a specific wavelength region onto the first ink 5a attached to the upper surface of the printing medium 4 by the first printing unit 3a.

[0187] For example, when the second ink 5b is a photo-curable ink, the first B light irradiation device 1b can cure the second ink 5b attached to the upper surface of the printing medium 4 by irradiating light in a specific wavelength region onto the second ink 5b attached to the upper surface of the printing medium 4 by the second printing unit 3b.

[0188] For example, in the case where the third ink 5c is a photocurable ink, the first C light irradiation device 1c can cure the third ink 5c attached to the upper surface of the printing medium 4 by the third printing unit 3c by irradiating light in a specific wavelength region onto the third ink 5c.

[0189] Here, for example, as described above, if the housing 14 of the first light irradiation device 1 is a thin rectangular parallelepiped shape, the first light irradiation device 1 can be arranged in each gap of the four printing units 3 in the transport direction of the printing medium 4 transported by the transport unit 2. Here, the thickness direction of the housing 14 of the first light irradiation device 1 can be arranged along the transport direction of the printing medium 4 transported by the transport unit 2. It should be noted that in Figure 17 the example shown, the first light irradiation device 1 (the first A light irradiation device 1a, the first B light irradiation device 1b, and / or the first C light irradiation device 1c) is arranged in such a manner that, with respect to the +X direction as the second direction, the third outer surface 14c faces the -X direction, the fourth outer surface 14d faces the +X direction, and the direction from the third outer surface 14c to the fourth outer surface 14d is set as the second direction. However, these arrangements can also be reversed. That is, the first light irradiation device 1 (the first A light irradiation device 1a, the first B light irradiation device 1b, and / or the first C light irradiation device 1c) can be arranged in such a manner that, with respect to the +X direction as the second direction, the fourth outer surface 14d faces the -X direction, the third outer surface 14c faces the +X direction, and the direction from the fourth outer surface 14d to the third outer surface 14c is set as the second direction. Therefore, as long as the second direction is the orientation along the thickness direction of the housing 14 with respect to the light irradiation device 1, it can also be any one of the two directions including the direction from the third outer surface 14c to the fourth outer surface 14d and the direction from the fourth outer surface 14d to the third outer surface 14c. In other words, it can be that the transport unit 2 can transport the printing medium 4 irradiated with light from the first opening 140a in the second direction, and the second direction is any one of the direction from the third outer surface 14c to the fourth outer surface 14d and the direction from the fourth outer surface 14d to the third outer surface 14c.

[0190] <<Second Light Irradiation Device 6>>

[0191] The second light irradiation device 6 can irradiate light onto the printing medium 4 transported by the transport unit 2 in the transport direction. In Figure 17 the example, the second light irradiation device 6 can irradiate the light onto the upper surface of the printing medium 4 by emitting light downward. In Figure 17In the figure, the outer edge of the light from the second light irradiation device 6 toward the upper surface of the printed medium 4 is schematically shown by a one-dot chain line. When the ink 5 is a photocurable ink, if the light irradiated from the second light irradiation device 6 onto the upper surface of the printed medium 4 is light in a specific wavelength region for causing the photocurable ink to cure (photocuring), the ink 5 attached to the upper surface of the printed medium 4 can be cured by the light from the second light irradiation device 6. For example, when the ink 5 is an ultraviolet curable ink (UV ink), if the light irradiated from the second light irradiation device 6 onto the upper surface of the printed medium 4 is ultraviolet light as light in a specific wavelength region, the ink 5 attached to the upper surface of the printed medium 4 can be cured.

[0192] Here, the intensity of the light in the specific wavelength region emitted from the second light irradiation device 6 can be made greater than the intensity of the light in the specific wavelength region emitted from the first light irradiation device 1. In this case, when the ink 5 is a photocurable ink, the ink 5 attached to the upper surface of the printed medium 4 is cured to a certain extent (also referred to as temporary curing) under the action of the light in the specific wavelength region emitted from the first light irradiation device 1, and then, further curing (also referred to as formal curing) can be achieved under the action of the light in the specific wavelength region emitted from the second light irradiation device 6.

[0193] In Figure 17In the printing apparatus 100 of the example, if the ink 5 is a photo-curable ink, the following operations can be performed. First, the droplets of the first ink 5a are attached to the upper surface of the printing medium 4 by the first printing unit 3a. Next, the first A light irradiation device 1a emits light in a specific wavelength region toward the upper surface of the printing medium 4, so that the droplets of the first ink 5a attached to the upper surface of the printing medium 4 are temporarily cured. Next, the droplets of the second ink 5b are attached to the upper surface of the printing medium 4 by the second printing unit 3b. Next, the first B light irradiation device 1b emits light in a specific wavelength region toward the upper surface of the printing medium 4, so that the droplets of the second ink 5b attached to the upper surface of the printing medium 4 are temporarily cured. Next, the droplets of the third ink 5c are attached to the upper surface of the printing medium 4 by the third printing unit 3c. Next, the first C light irradiation device 1c emits light in a specific wavelength region toward the upper surface of the printing medium 4, so that the droplets of the third ink 5c attached to the upper surface of the printing medium 4 are temporarily cured. Next, the droplets of the fourth ink 5d are attached to the upper surface of the printing medium 4 by the fourth printing unit 3d. Then, the second light irradiation device 6 irradiates light in a specific wavelength region toward the upper surface of the printing medium 4, so that the droplets of the first ink 5a, the second ink 5b, and the third ink 5c that have been temporarily cured on the upper surface of the printing medium 4 are fully cured, and the droplets of the fourth ink 5d attached to the upper surface of the printing medium 4 are cured.

[0194] According to this operation, on the upper surface of the printing medium 4, after the droplets of the first ink 5a are cured to a certain extent, the droplets of the second ink 5b are attached. Therefore, it is possible to reduce the occurrence of mixing between the first ink 5a and the second ink 5b caused by the contact between the droplets of the first ink 5a and the droplets of the second ink 5b on the upper surface of the printing medium 4. In addition, on the upper surface of the printing medium 4, after the droplets of the first ink 5a and the second ink 5b are cured to a certain extent, the droplets of the third ink 5c are attached. Therefore, it is possible to reduce the occurrence of mixing of the ink caused by the contact between the droplets of the first ink 5a, the droplets of the second ink 5b, and the droplets of the third ink 5c on the upper surface of the printing medium 4. In addition, on the upper surface of the printing medium 4, after the droplets of the first ink 5a, the second ink 5b, and the third ink 5c are cured to a certain extent, the droplets of the fourth ink 5d are attached. Therefore, it is possible to reduce the occurrence of mixing of the ink caused by the contact between the droplets of the first ink 5a, the droplets of the second ink 5b, the droplets of the third ink 5c, and the droplets of the fourth ink 5d on the upper surface of the printing medium 4. Thus, in the printing apparatus 100, it is possible to reduce the occurrence of defects such as bleeding and color mixing of the ink on the upper surface of the printing medium 4, thereby improving the quality of the printed ink pattern.

[0195] Figure 18 is a top view schematically showing an example of the forms of four types of inks 5 attached to the upper surface of the printing medium 4. In Figure 18 , the droplets of the first ink 5a are shown by circles marked with cross-hatching using upper left diagonal lines. The droplets of the second ink 5b are shown by circles marked with cross-hatching using upper right diagonal lines. The droplets of the third ink 5c are shown by circles marked with cross-hatching like sand. The droplets of the fourth ink 5d are shown by blackened circles.

[0196] <<Control unit 9>>

[0197] The control unit 9 can control the operations of various parts of the printing apparatus 100. The control unit 9 has various circuits such as a processor and a memory, for example. The control unit 9 is electrically connected to various parts of the printing apparatus 100 using a cable or the like, for example. For example, the control unit 9 can be electrically connected to the connector 17 of the first light irradiation device 1 via a cable or the like. The control unit 9 can be electrically connected to the connector 67 of the second light irradiation device 6 via a cable or the like, for example. The control unit 9 can be electrically connected to the transport unit 2 and the printing unit 3 via a cable or the like, for example.

[0198] The control unit 9 can control the transport of the printing medium 4 by the transport unit 2, for example. The control unit 9 can control the ejection of ink by the IJ head as the printing unit 3, for example. The control unit 9 can control the light emission of each of the first light irradiation device 1 and the second light irradiation device 6, for example.

[0199] For example, if the ink 5 is a photocurable ink, information indicating the characteristics of light that can relatively well perform the photocuring of the ink 5 ejected from the IJ head as the printing unit 3 can be stored in the memory of the control unit 9. As a specific example of this information, numerical values indicating the wavelength distribution characteristics of light suitable for causing photocuring of the droplets of the ink 5 ejected from the IJ head and the intensity of light (the emission intensity in each wavelength region) can be cited. In the printing apparatus 100, for example, the control unit 9 can also adjust the magnitude of the drive current input to the plurality of light emitting elements 112 in the light source 11 of the first light irradiation device 1 based on the information in the memory. Thereby, for example, the first light irradiation device 1 can emit light with an appropriate light amount corresponding to the characteristics of the ink used, and the ink 5 can be photocured with relatively low energy light. In addition, the control unit 9 can also adjust the magnitude of the drive current input to the light emitting elements of the second light irradiation device 6 based on the information in the memory.

[0200] <<Dimensions of the first light irradiation device>>

[0201] Here, for example, consider a case where the printing apparatus 100 has a form of a line printer in which the width of the IJ head as the printing unit 3 is approximately the same as the width of the printing medium 4. In this case, for example, by arranging a plurality of first light irradiation devices 1 in the +Y direction, which is the width direction of the printing medium 4, the width of the printing medium 4 can be made substantially the same as the total width of the plurality of first light irradiation devices 1. Here, for example, the first length, the second length, and the third length of the first light irradiation device 1 can be appropriately set within a range that satisfies the condition that the width of the printing medium 4 in the +Y direction, which is the width direction of the printing medium 4, is substantially the same as the total width of the plurality of first light irradiation devices 1.

[0202] For example, by arranging a plurality of first A light irradiation devices 1a in the +Y direction, which is the width direction of the printing medium 4, the width of the printing medium 4 can be made substantially the same as the total width of the plurality of first A light irradiation devices 1a. Here, for example, the first length, the second length, and the third length of the first A light irradiation device 1a can be appropriately set within a range that satisfies the condition that the width of the printing medium 4 in the +Y direction, which is the width direction of the printing medium 4, is substantially the same as the total width of the plurality of first A light irradiation devices 1a.

[0203] For example, by arranging a plurality of first B light irradiation devices 1b in the +Y direction, which is the width direction of the printing medium 4, the width of the printing medium 4 can be made substantially the same as the total width of the plurality of first B light irradiation devices 1b. Here, for example, the first length, the second length, and the third length of the first B light irradiation device 1b can be appropriately set within a range that satisfies the condition that the width of the printing medium 4 in the +Y direction, which is the width direction of the printing medium 4, is substantially the same as the total width of the plurality of first B light irradiation devices 1b.

[0204] For example, by arranging a plurality of first C light irradiation devices 1c in the +Y direction, which is the width direction of the printing medium 4, the width of the printing medium 4 can be made substantially the same as the total width of the plurality of first C light irradiation devices 1c. Here, for example, the first length, the second length, and the third length of the first C light irradiation device 1c can be appropriately set within a range that satisfies the condition that the width of the printing medium 4 in the +Y direction, which is the width direction of the printing medium 4, is substantially the same as the total width of the plurality of first C light irradiation devices 1c.

[0205] <<Fixing of the First Light Irradiation Device in the Printing Apparatus>>

[0206] Figure 19 is a front view showing an example of the light irradiation device (first light irradiation device) 1 in a state of being fixed to the fixed portion 7 of the printing apparatus 100. InFigure 19 In Figure 19 , the bases 121 and the outer edges of the protruding portions 122 of the heat dissipation member 12 located inside the light irradiation device (first light irradiation device) 1 are schematically shown by thin dashed lines as hidden lines.

[0207] The printing device 100 has, for example, a portion (also referred to as a fixed portion) 7 for fixing the first light irradiation device 1. The fixed portion 7 can be fixed to, for example, the housing or the base of the printing device 100. The material of the fixed portion 7 is, for example, a metal with excellent thermal conductivity such as aluminum or stainless steel. The fixed portion 7 can be, for example, a thick plate-like portion.

[0208] The first light irradiation device 1 can be fixed to the fixed portion 7, for example, by fastening connection such as screw fastening. In Figure 19 the example, the fixed portion 7 can be a thick plate-like portion having a plate surface along a virtual plane parallel to the YZ plane. The shaft portion 8a of the external thread member 8 passing through the through-hole portion (also referred to as the first through-hole portion) 7h that penetrates the fixed portion 7 in the -X direction can be fitted into the threaded hole portion Sh1 that penetrates the fourth wall portion 144 of the first light irradiation device 1. The external thread member 8 can be a bolt having a head 8h and a shaft portion 8a protruding from the head 8h. The shaft portion 8a of the external thread member 8 can be an elongated cylindrical portion having a spiral external thread portion on the outer peripheral portion. The threaded hole portion Sh1 can be a portion having a spiral internal thread portion disposed on the inner peripheral portion of the through-hole. In this case, the fixed portion 7 has the first through-hole portion 7h, and the printing device 100 includes the external thread member 8 for fixing the first light irradiation device 1 to the fixed portion 7. In Figure 19 Figure 19 , the outer edges of the threaded hole portion Sh1, the first through-hole portion 7h, and the shaft portion 8a are schematically shown by thin dashed lines as hidden lines. Here, for example, the first through-hole portion 7h can also be a threaded hole portion having a spiral internal thread portion on the inner peripheral portion.

[0209] Here, for example, it can also be as Figure 3 shown, the fourth wall portion 144 has a first threaded hole portion Sh1 and a second threaded hole portion Sh1, and the fixed portion 7 has a first first through-hole portion 7h and a second first through-hole portion 7h. In this case, the shaft portion 8a of the first external thread member 8 passing through the first first through-hole portion 7h that penetrates the fixed portion 7 in the -X direction can be fitted into the first threaded hole portion Sh1 that penetrates the fourth wall portion 144 of the first light irradiation device 1. The shaft portion 8a of the second external thread member 8 passing through the second first through-hole portion 7h that penetrates the fixed portion 7 in the -X direction can be fitted into the second threaded hole portion Sh1 that penetrates the fourth wall portion 144 of the first light irradiation device 1.

[0210] Thus, if the first light irradiation device 1 is fixed to the fixed part 7 by screwing at a plurality of parts using a plurality of external thread members 8, the first light irradiation device 1 can be stably fixed in the printing device 100. Here, for example, the first light irradiation device 1 can also be fixed to the fixed part 7 by screwing at three or more parts using three or more external thread members 8.

[0211] Here, the fixed part 7 can have, for example, an outer surface (also referred to as the seventh outer surface) 7s that is in surface contact with the fourth outer surface 14d in the housing 14 of the first light irradiation device 1. And, for example, in the first light irradiation device 1, if the housing 14 is in contact with the heat dissipation member 12, the heat dissipation member 12 can be cooled more efficiently by heat transfer from the heat dissipation member 12 through the housing 14 to the fixed part 7. Here, surface contact includes contact between a plane and a plane. For example, the state where the fourth outer surface 14d is in surface contact with the seventh outer surface 7s includes a state where a flat part of the fourth outer surface 14d is in contact with a flat part of the seventh outer surface 7s.

[0212] Here, for example, as a member for fixing the first light irradiation device 1 to the fixed part 7, a member different from the external thread member 8 can also be used. The different member can be, for example, a member that fixes the first light irradiation device 1 to the fixed part 7 by clamping. For example, as a specific example of the different member, a clamping member can be used. This clamping member can be fixed to the fixed part 7 and clamp the first light irradiation device 1, or can fix the first light irradiation device 1 to the fixed part 7 by clamping the fixed part 7 and the first light irradiation device 1 together.

[0213] Figure 20 It is a right view showing the appearance of the light irradiation device (first light irradiation device) 1 which is another example of the first embodiment. Figure 21 It is a right view showing the appearance of another example of the heat dissipation member 12. Figure 22 It is a front view showing the appearance of another example of the heat dissipation member 12. Figure 23 It is a front view showing another example of the light irradiation device (first light irradiation device) 1 in a state of being fixed to the fixed part 7 of the printing device 100. In Figure 23 it, the outer edges of the base part 121 and the protrusion part 122 of the heat dissipation member 12 located inside the light irradiation device (first light irradiation device) 1 are schematically shown by thin dashed lines as hidden lines.

[0214] Here, for example, as Figure 21 and Figure 22 shown, the base part 121 of the heat dissipation member 12 of the first light irradiation device 1 can also have a threaded hole part Sh2 on the side of the fourth outer surface 14d. In Figure 22 and Figure 23In [the figure], the outer edge of the threaded hole portion Sh2 is schematically shown by a thin dashed line as a hidden line. The threaded hole portion Sh2 can be, for example, a portion having a spiral internal thread portion on the inner peripheral portion of a hole portion that is recessed in a cylindrical shape. And, as Figure 20 shown, the housing 14 of the first light irradiation device 1 can also have a through hole portion (also referred to as the second through hole portion) 144h that opens on the fourth outer surface 14d and is connected to the threaded hole portion Sh2. In Figure 23 , the outer edges of the first through hole portion 7h, the second through hole portion 144h, and the shaft portion 8a are each schematically shown by a thin dashed line as a hidden line. And, as Figure 23 shown, the external thread member 8 can also penetrate through the first through hole portion 7h and the second through hole portion 144h and be fitted into the threaded hole portion Sh2. More specifically, the shaft portion 8a of the external thread member 8 can also penetrate through the first through hole portion 7h and the second through hole portion 144h and be fitted into the threaded hole portion Sh2.

[0215] According to this structure, the first light irradiation device 1 can be easily fixed to the fixed portion 7 in a state where the fourth outer surface 14d of the housing 14 is in surface contact with the seventh outer surface 7s of the fixed portion 7. And, the heat transfer from the heat dissipation member 12 to the fixed portion 7 via the housing 14 can be increased. As a result, efficient cooling of the heat dissipation member 12 utilizing heat transfer can be easily achieved. Here, if the material of the external thread member 8 is a metal having excellent thermal conductivity, more efficient cooling of the heat dissipation member 12 can be achieved. For example, the first through hole portion 7h can be a threaded hole portion having a spiral internal thread portion on the inner peripheral portion, and the second through hole portion 144h can be a threaded hole portion having a spiral internal thread portion on the inner peripheral portion.

[0216] Here, for example, it can also be as in the example of Figure 20 where the fourth wall portion 144 has a first second through hole portion 144h and a second second through hole portion 144h, and the fixed portion 7 has a first first through hole portion 7h and a second first through hole portion 7h. And, it can also be as in the examples of Figure 21 and Figure 22 where the base portion 121 has a first threaded hole portion Sh2 connected to the first second through hole portion 144h and a second threaded hole portion Sh2 connected to the second second through hole portion 144h.

[0217] In this case, for example, the shaft portion 8a of the first external thread member 8 that penetrates through the first first through-hole portion 7h and the first second through-hole portion 144h can be fitted into the first threaded hole portion Sh2 of the base portion 121. The first first through-hole portion 7h penetrates the fixed portion 7 in the -X direction, and the first second through-hole portion 144h penetrates the housing 14 in the -X direction. For example, the shaft portion 8a of the second external thread member 8 that penetrates through the second first through-hole portion 7h and the second second through-hole portion 144h can be fitted into the second threaded hole portion Sh2 of the base portion 121. The second first through-hole portion 7h penetrates the fixed portion 7 in the -X direction, and the second second through-hole portion 144h penetrates the housing 14 in the -X direction.

[0218] Thus, if the first light irradiation device 1 is fixed to the fixed portion 7 by screw fastening at a plurality of portions using a plurality of external thread members 8, the first light irradiation device 1 can be stably fixed in the printing device 100. Here, for example, the first light irradiation device 1 can also be fixed to the fixed portion 7 by screw fastening at three or more portions using three or more external thread members 8.

[0219] <1-3. Summary of the First Embodiment>

[0220] In the light irradiation device 1 of the first embodiment, the second opening 140b opens in the region on the first outer surface 14a side in the third outer surface 14c and connects the internal space 14i of the housing 14 to the external space 14o. The third opening 140c opens in the region of the portion on the second outer surface 14b side from the second outer surface 14b to the third outer surface 14c and connects the internal space 14i of the housing 14 to the external space 14o. The heat dissipation member 12 includes a base portion 121 located in the region on the first outer surface 14a side in the internal space 14i, and a plurality of protruding portions 122 protruding from the base portion 121 toward the second outer surface 14b along the first direction. The light source 11 is located on the first outer surface 14a side of the base portion 121. A plurality of gaps 12s between the plurality of protruding portions 122 are adjacent to the second opening 140b. The drive portion 13 is located between the plurality of protruding portions 122 and the second outer surface 14b in the internal space 14i.

[0221] According to this structure, when the first outer surface 14a is disposed downward, the third opening 140c is disposed above the second outer surface 14b facing upward to the upper portion of the third outer surface 14c. Therefore, for example, even if there is a connector 17 or the like on the second outer surface 14b side, it is possible to ensure the size of the opening required for exhausting from the internal space 14i to the external space 14o in the third opening 140c, and the distance between the plurality of protrusions 122 and the third opening 140c becomes longer. Thereby, a smooth upward airflow can be generated from the plurality of gaps 12s between the plurality of protrusions 122 toward the third opening 140c, and the speed of the upward airflow increases due to the chimney effect. As a result, the heat dissipation member 12 can be efficiently cooled. Thus, even if a cooling fan is not provided in the light irradiation device 1, the heat dissipation member 12 can be efficiently cooled. Therefore, it is possible to achieve miniaturization of the light irradiation device 1, simplification of the structure, reduction of failures, and improvement of cooling performance.

[0222] <2. Other Embodiments>

[0223] The present invention is not limited to the above-described first embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

[0224] In the above-described first embodiment, for example, the shape of each of the plurality of protrusions 122 in the heat dissipation member 12 is not limited to a thin plate shape, and may be other shapes such as a rod shape.

[0225] In the above-described first embodiment, for example, a mesh member may be disposed in the second opening 140b. Thereby, the intrusion of foreign matters from the external space 14o of the housing 14 into the internal space 14i can be reduced. Foreign matters can include, for example, dust, dirt, metal parts, and tools.

[0226] In the above-described first embodiment, for example, the external space 14o and the internal space 14i of the light irradiation device 1 may be filled with a gas such as an inert gas containing nitrogen instead of air. In this case, the flow of air discharged from the external space 14o through the second opening 140b, the internal space 14i, and the third opening 140c to the external space 14o in sequence becomes the flow of gas.

[0227] In the above-described first embodiment, for example, the printing device 100 may have two or more printing units 3 such as three printing units 3 instead of four printing units 3. For example, when the printing device 100 has three printing units 3, in Figure 17In the example, the fourth printing unit 3d and the first C light irradiation device 1c can also be removed. In this case, for example, for the first color, the second color, and the third color, red (R), green (G), and blue (B) can be applied, respectively. Here, for example, the first color can also be any one of red (R), green (G), and blue (B). For example, the second color can also be any one of red (R), green (G), and blue (B) that is different from the first color. For example, the third color can also be any one of red (R), green (G), and blue (B) that is different from the first color and the second color.

[0228] In the above-described first embodiment, for example, instead of the three first light irradiation devices 1, the printing device 100 can also include one or more first light irradiation devices 1. For example, when the printing device 100 has three printing units 3, in Figure 17 the example, the fourth printing unit 3d and the first C light irradiation device 1c can also be removed. For example, when the printing device 100 has two printing units 3, in Figure 17 the example, the third printing unit 3c, the fourth printing unit 3d, the first B light irradiation device 1b, and the first C light irradiation device 1c can also be removed.

[0229] In the above-described first embodiment, for example, the IJ head of the printing unit 3 can also eject aqueous or oily ink as the ink 5 instead of the photocurable ink. In this case, for example, the light irradiated by the first light irradiation device 1 onto the upper surface of the printing medium 4 can be light in a specific wavelength region that includes infrared rays for drying and fixing the ink 5 attached to the upper surface of the printing medium 4.

[0230] In the above-described first embodiment, for example, the printing unit 3 is not limited to a structure having an IJ head, and can also have a structure different from the IJ head. For example, the printing unit 3 can also use an electrostatic head. The electrostatic head can be a type of head that charges the printing medium 4 and uses the electrostatic force generated by the static electricity of the printing medium 4 to attach a developer (toner). The printing unit 3 can also use a structure that conveys a developer (toner) through a brush, a brush, a roller, etc. Here, for example, as the developer, a UV-curable toner that cures in response to UV irradiation or a heat-curable toner that cures in response to infrared irradiation can be used.

[0231] In the above-described first embodiment, for example, the ink 5 can also be changed to a photosensitive resist or a photocurable resin as a photosensitive material.

[0232] In the above-described first embodiment, for example, the light irradiation device 1 is applied to the printing device 100 including the printing unit 3, but is not limited thereto. For example, the light irradiation device 1 may also be applied to a device that cures a photosensitive resin after applying a paste containing a photosensitive resin such as a resist by spin coating or screen printing on the surface of an object such as a substrate. Further, for example, in an exposure device that exposes a photosensitive resin such as a resist, the light irradiation device 1 may be applied as a light source for exposure.

[0233] In the above-described first embodiment, for example, the light irradiation device 1 may also be applied to other fields different from the printing field such as the printing device 100.

[0234] For example, it may also be applied to the field of assembly manufacturing including uses such as curing an adhesive or a resin in the installation of electronic components. The curing of the adhesive or the resin may also be a certain degree of curing (temporary curing) of the adhesive or the resin. Here, for example, if the adhesive is an ultraviolet-curable adhesive, the adhesive can be cured by ultraviolet rays emitted from the light irradiation device 1. For example, if the adhesive is a heat-curable adhesive, the adhesive can be cured by infrared rays emitted from the light irradiation device 1. For example, if the adhesive material is an adhesive that cures by drying, the adhesive can be dried and cured by infrared rays emitted from the light irradiation device 1. For example, if the resin is an ultraviolet-curable resin that cures in response to ultraviolet irradiation, the ultraviolet-curable resin can be cured by ultraviolet rays emitted from the light irradiation device 1.

[0235] Further, for example, the light irradiation device 1 may also be applied to the field of drying processing including uses such as efficiently drying an irradiated object by infrared irradiation. For example, the light irradiation device 1 may also be applied to the medical-related field including uses such as sterilization by ultraviolet or violet light irradiation.

[0236] As described above in detail, the light irradiation device 1 and the printing device 100 have been described, but the above description is illustrative in all aspects, and the present invention is not limited thereto. In addition, the above various examples can be combined as long as they do not conflict with each other. And countless examples that are not illustrated can be conceived without departing from the scope of the present invention.

[0237] The present invention includes the following.

[0238] In one embodiment, (1) a light irradiation device includes: a light source including a plurality of light-emitting elements; a heat dissipation member thermally connected to the light source; a driving unit including a driving circuit for driving the light source; and a rectangular parallelepiped-shaped housing that houses the light source, the heat dissipation member, and the driving unit. The housing has a rectangular first outer surface, a rectangular second outer surface on the side opposite to the first outer surface, a rectangular third outer surface connecting the first outer surface and the second outer surface, a rectangular fourth outer surface connecting the first outer surface and the second outer surface and on the side opposite to the third outer surface, a rectangular fifth outer surface connecting the first outer surface and the second outer surface and connecting the third outer surface and the fourth outer surface, and a rectangular sixth outer surface connecting the first outer surface and the second outer surface, connecting the third outer surface and the fourth outer surface, and on the side opposite to the fifth outer surface. The housing has a first opening that is at least open on the first outer surface and allows light from the light source to pass through, a second opening that is open in a region on the first outer surface side of the third outer surface and connects the internal space of the housing to the external space, and a third opening that is open in a region of a part from the second outer surface to the second outer surface side of the third outer surface and connects the internal space to the external space. The heat dissipation member includes a base portion located in a region on the first outer surface side of the internal space, and a plurality of protrusions protruding from the base portion toward the second outer surface along a first direction from the first outer surface toward the second outer surface. The light source is located on the first outer surface side of the base portion. A plurality of gaps between the plurality of protrusions are adjacent to the second opening. The driving unit is located between the plurality of protrusions and the second outer surface in the internal space.

[0239] (2) In the light irradiation device of the above (1), it may also be that in the first direction, the length of the second opening is less than or equal to the length of the plurality of protrusions, and a portion on the base portion side of the plurality of gaps is adjacent to the second opening.

[0240] (3) In the light irradiation device of the above (2), the housing has a first inner surface on the third outer surface side of the internal space, and a portion on the second outer surface side of the plurality of protrusions contacts the first inner surface.

[0241] (4) In the light irradiation device according to any one of (1) to (3) above, the drive circuit may include one or more electronic components, and the one or more electronic components are located between the second opening and the third opening in the first direction. The drive unit is located in a region of the internal space that is closer to the fourth outer surface than the third outer surface, and is arranged in a state where the one or more electronic components face the third outer surface side.

[0242] In one embodiment, (5) The printing device includes: the light irradiation device according to any one of (1) to (4) above; a conveyance unit that conveys a printing medium irradiated with light from the first opening portion in a second direction, the second direction being from the third outer surface toward the fourth outer surface or from the fourth outer surface toward the third outer surface; and a printing unit that is located on the side opposite to the second direction of the light irradiation device, with the first outer surface facing downward.

[0243] (6) In the printing device according to (5) above, it may also include a fixed portion for fixing the light irradiation device, the housing is in contact with the heat dissipation member, and the fixed portion has a seventh outer surface that is in surface contact with the fourth outer surface of the housing.

[0244] (7) In the printing device according to (6) above, it may also include an external thread member for fixing the light irradiation device to the fixed portion. The fixed portion has a first through hole portion, the base portion has a threaded hole portion on the side of the fourth outer surface, the housing has a second through hole portion that opens on the fourth outer surface and is connected to the threaded hole portion, and the external thread member penetrates through the first through hole portion and the second through hole portion and is embedded in the threaded hole portion.

[0245] Description of Reference Numerals

[0246] 1 Light irradiation device (first light irradiation device)

[0247] 100 Printing device

[0248] 11 Light source

[0249] 112 Light emitting element

[0250] 12 Heat dissipation member

[0251] 121 Base portion

[0252] 122 Protrusion

[0253] 12s Gap

[0254] 13 Drive unit

[0255] 132 Driving Circuit

[0256] 132i Electronic Component

[0257] 14 Housing

[0258] 140a First Opening

[0259] 140b Second Opening

[0260] 140c Third Opening

[0261] 144h Second Through-Hole Portion

[0262] 14a First Outer Surface

[0263] 14b Second Outer Surface

[0264] 14c Third Outer Surface

[0265] 14d Fourth Outer Surface

[0266] 14e Fifth Outer Surface

[0267] 14f Sixth Outer Surface

[0268] 14i Internal Space

[0269] 14o External Space

[0270] 2 Conveyor Section

[0271] 3 Printing Section

[0272] 4 Printed Medium

[0273] 5 Ink

[0274] 6 Second Light Irradiation Device

[0275] 7 Fixed Portion

[0276] 7h First Through-Hole Portion

[0277] 7s Seventh Outer Surface

[0278] 8 External Thread Member

[0279] Iw1 First Inner Surface

[0280] SL1 Slit Hole Portion

[0281] Sh2 Threaded Hole Portion.

Claims

1. A light irradiation device, wherein, the light irradiation device includes: a light source including a plurality of light-emitting elements; a heat dissipation member thermally connected to the light source; a driving unit including a driving circuit for driving the light source; and a rectangular parallelepiped-shaped housing that houses the light source, the heat dissipation member, and the driving unit, the housing has a first outer surface, a second outer surface, a third outer surface, a fourth outer surface, a fifth outer surface, and a sixth outer surface, the first outer surface is a rectangular surface, the second outer surface is a rectangular outer surface on the side opposite to the first outer surface in the housing, the third outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface, the fourth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface and is on the side opposite to the third outer surface, the fifth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface and connects the third outer surface and the fourth outer surface, the sixth outer surface is a rectangular outer surface in the housing that connects the first outer surface and the second outer surface, connects the third outer surface and the fourth outer surface, and is on the side opposite to the fifth outer surface, the housing has a first opening, a second opening, and a third opening, the first opening opens at least on the first outer surface and allows light from the light source to pass through, the second opening opens in a region on the first outer surface side in the third outer surface and connects the internal space of the housing to the external space, the third opening opens in a region of a part from the second outer surface to the second outer surface side in the third outer surface and connects the internal space to the external space, the heat dissipation member includes a base portion and a plurality of protrusion portions, the base portion is located in a region on the first outer surface side in the internal space, the plurality of protrusion portions protrude from the base portion toward the second outer surface along a first direction from the first outer surface toward the second outer surface, the light source is located on the first outer surface side of the base portion, a plurality of gaps between the plurality of protrusion portions are adjacent to the second opening, the driving unit is located between the plurality of protrusion portions and the second outer surface in the internal space.

2. The light irradiation device according to claim 1, wherein, in the first direction, the length of the second opening is not more than the length of the plurality of protrusion portions, a portion on the base portion side in the plurality of gaps is adjacent to the second opening.

3. The light irradiation device according to claim 2, wherein, the housing has a first inner surface on the third outer surface side of the internal space, a portion on the second outer surface side in the plurality of protrusion portions contacts the first inner surface.

4. The light irradiation device according to any one of claims 1 to 3, wherein, the driving circuit includes one or more electronic components, The one or more electronic components are located between the second opening and the third opening in the first direction. The drive unit is located in a region of the internal space that is closer to the fourth outer surface than the third outer surface, and is arranged in a state where the one or more electronic components face the third outer surface side.

5. A printing apparatus, wherein the printing apparatus includes: the light irradiation device according to any one of claims 1 to 4; a conveyance unit that conveys a printing medium irradiated with light from the first opening in a second direction, which is a direction from the third outer surface toward the fourth outer surface or from the fourth outer surface toward the third outer surface; and a printing unit that is located on a side in a third direction opposite to the second direction of the light irradiation device, wherein the first outer surface is disposed downward.

6. The printing apparatus according to claim 5, wherein the printing apparatus includes a fixed portion to which the light irradiation device is fixed, the housing is in contact with the heat dissipation member, the fixed portion has a seventh outer surface that is in surface contact with the fourth outer surface of the housing.

7. The printing apparatus according to claim 6, wherein the printing apparatus includes an external thread member that fixes the light irradiation device to the fixed portion, the fixed portion has a first through-hole portion, the base portion has a threaded hole portion on the side of the fourth outer surface, the housing has a second through-hole portion that opens on the fourth outer surface and is connected to the threaded hole portion, and the external thread member penetrates through the first through-hole portion and the second through-hole portion and is fitted into the threaded hole portion.

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