JP5298781B2 - LED irradiation device - Google Patents

Description

  The present invention relates to an irradiation apparatus that irradiates a photocurable material with light and cures, and more particularly to an LED irradiation apparatus that uses an LED (Light Emitting Diode) as a light source.

2. Description of the Related Art Conventionally, an ink jet recording apparatus that forms an image by ejecting ink that is cured by irradiation with light such as ultraviolet rays onto a recording medium using an ink jet head and curing the ink by light irradiation is known (for example, Patent Documents). 1, see Patent Document 2). Such an ink jet recording apparatus is characterized by being friendly to the environment, capable of recording on various recording media at high speed, and obtaining a high-definition image that is difficult to bleed. In such an ink jet recording apparatus, after the ink has landed on the recording medium, the image quality is improved by quickly photocuring the ink. For this purpose, a high output and relatively large light irradiation apparatus is used. is necessary.
On the other hand, it comprises a plurality of linear light sources configured by arranging a large number of LEDs in a row and a concave reflecting mirror corresponding to each linear light source, and each concave reflecting mirror collects each light of the linear light source at the same location. A linear illumination device that emits light is known (see, for example, Patent Document 3).
JP 2005-125792 A JP 2006-35648 A JP 2002-93227 A

Therefore, it is possible to reduce the size of the apparatus by adopting the linear illumination device instead of a lamp-type light source such as a metal halide lamp or a mercury lamp as the light source of the light irradiation device. However, the light output of the ultraviolet LED is smaller than that of the lamp-type light source. For this reason, in order to ensure the ultraviolet intensity required for ink hardening, since many ultraviolet LED is needed, the heat_generation | fever of a light source becomes a problem.
This invention is made | formed in view of the situation mentioned above, and it aims at providing the LED irradiation apparatus which provided the some LED in the light source, and made the heat dissipation of this light source favorable.

In order to achieve the above object, according to the present invention, LED units each having a plurality of LEDs arranged in a row on a substrate are provided on both sides of an end portion of a heat conducting plate having thermal conductivity, and a reflecting surface is formed. constitute the light source unit is fixed to the heat conductive plate sandwiches the substrate of each of the LED units in a pair of reflectors, the heat radiation member is fixed to one surface of the heat conducting plate extending from the light source portion and the heat radiating A heat dissipating heat from the light source unit from a member , fixing a control board including an LED drive circuit to the other surface of the heat conducting plate with a spacer interposed therebetween, and a fan for blowing cooling air to the side of the heat conducting plate There is provided an LED irradiation apparatus characterized by the above.

  In the LED irradiation apparatus according to the present invention, the light source unit includes auxiliary reflecting mirrors disposed at both ends of the LED unit.

  In the LED irradiation apparatus according to the present invention, a groove for diffusing reflected light is formed on the reflection surface of the reflector.

According to the present invention, LED units each having a plurality of LEDs arranged in a row on a substrate are provided on both sides of an end portion of a heat conducting plate having thermal conductivity, and the reflector having a reflecting surface is provided as the LED unit. A light source part is provided for each, a heat radiating member is provided on the heat conducting plate extending from the light source part, and heat from the light source part is radiated from the heat radiating member.
With such a configuration, since the light source section includes two LED units, it is possible to increase the irradiation intensity, and because these LED units are provided on both surfaces of the heat conductive plate provided with the heat dissipation member, sufficient heat dissipation is obtained. It is done.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a front surface, a plane surface, a bottom surface, a right side surface, and a left side surface of the LED irradiation apparatus 1 according to the present embodiment. The LED irradiation device 1 is provided in an ink jet recording apparatus, and is provided on the downstream side of the recording medium conveyance path with respect to the ink jet head, and applies ultraviolet light to the ultraviolet curable ink ejected onto the recording medium by the ink jet head. Irradiates to cure. As the recording medium, any medium can be used as long as the medium can be coated with ultraviolet curable ink, such as paper, cloth, and plastic molded product.

  As shown in FIG. 1, the LED irradiation device 1 includes a horizontally long box-shaped housing 3 extending to a length corresponding to the width of the recording medium, and power lines and signal lines are provided on the top surface of the housing 3. A connected input terminal block 5 and a dimming volume 7 for adjusting the amount of irradiation light are provided. An intake fan 9 is provided on the left side surface of the housing 3, and an exhaust port 11 is formed on the right side surface of the housing 3 so as to face the intake fan 9. Cooling air flows to the left and right. An irradiation opening 13 having a rectangular opening is formed on the bottom surface of the housing 3, and the irradiation opening 13 is covered with a front glass 14 made of, for example, quartz glass that is transparent to ultraviolet rays. The housing 3 has a built-in light source unit 15 including a large number of LEDs 16 facing the irradiation opening 13.

FIG. 2 is a diagram schematically showing the internal structure of the LED irradiation apparatus 1.
As shown in this figure, inside the housing 3, a light source unit 15 is disposed on the lower side which is the irradiation opening 13 side, and a control board 17 and a heat radiating plate 19 are disposed on the upper side.
The control board 17 is formed in a substantially rectangular shape and includes an LED drive board. The LED drive board is provided with a drive circuit that turns on the LED 16 with the power input via the input terminal block 5 and controls the amount of light according to the operation of the dimming volume 7.
The heat radiating plate 19 radiates heat generated by the light source unit 15, and a plurality of heat radiating extending from the housing 3 to the left and right on a plate made of a high thermal conductivity material formed to be approximately the same size as the control board 17. The fin 21 is integrally formed. Cooling air introduced into the housing 3 by the intake fan 9 is blown to the heat radiating fins 21 to radiate heat from the heat radiating fins 21.

FIG. 3 is an enlarged view of the light source unit 15.
The light source unit 15 includes an LED unit 25 and a reflector 29.
The LED unit 25 is configured by mounting a plurality (12 in FIG. 2) of LEDs 16 in a row on a strip-shaped mounting substrate 23 to form a linear light source. Each of the LEDs 16 is an ultraviolet LED that emits light having a wavelength of 365 nm. The light source unit 15 includes two such LED units 25, and each LED unit 25 is joined back to back with an end of a steel plate (heat conducting plate) 30 interposed therebetween.

The reflector 29 is provided for each LED unit 25 such that a cylindrical concave surface is extruded as the reflection surface 27 and the reflection surface 27 faces the LED unit 25. Each reflective surface 27 is an elliptical reflective surface having a first focal point F1 and a second focal point F2, and is disposed so that the second focal point F2 of each reflective surface 27 overlaps the same position. Moreover, LED16 is arrange | positioned at the 1st focus F1 of each reflective surface 27, Thereby, the light of each LED unit 25 is condensed on the 2nd focus F2. Then, when the recording surface of the recording medium passes through the second focal point F2, the ultraviolet curable ink on the recording surface is irradiated with ultraviolet rays and the ultraviolet curable ink is cured.
At this time, since the light source unit 15 includes the two LED units 25 joined back to back as described above, the second focal point F2 has sufficient ultraviolet intensity required for curing the ultraviolet curable ink. can get.

Each of the pair of reflectors 29 is integrally formed with two L-shaped fixing pieces 31 in the longitudinal direction, and the fixing pieces 31 of the respective reflectors 29 are formed in the pair of LED units 25. The mounting substrate 23 and the steel plate 30 are sandwiched and fixed by a spiral 32 (FIG. 2). Thus, as the reflector 29 is fixed to the steel plate 30, the relative position between the reflecting surface 27 of the reflector 29 and the LED unit 25 is uniquely determined. The position can be easily and accurately positioned, and the assemblability can be improved.
The mounting substrate 23 is exposed between the two fixed pieces 31 provided in the longitudinal direction of the reflector 29, and a signal line from the control substrate 17 is connected to the exposed portion.

  As shown in FIG. 2, the steel plate 30 has an upper end extending to the vicinity of the upper surface of the housing 3, the control board 17 is fixed to one surface thereof by a spacer 24, and the heat radiating plate 19 is attached to the other surface. Are closely attached. The steel plate 30 also functions as a heat conductive material, and the heat generated by each LED unit 25 of the light source unit 15 assembled at the end portion is efficiently transferred to the heat radiating plate 19 and is radiated from the heat radiating plate 19. As a result, in order to obtain sufficient UV intensity necessary for curing the UV curable ink, the LED unit 25 includes a large number of LEDs 16 or even when the LED 16 has a high output, heat is generated in the light source unit 15. Sufficient heat dissipation is obtained. Moreover, since the lifetime of LED16 is extended by this, a luminous flux maintenance factor can be improved.

  Further, since the light source unit 15, the control board 17, and the heat radiating plate 19, which are the built-in components of the housing 3, are assembled to the steel plate 30 as described above, the built-in components can be handled as one unit. Is fixed to the housing 3 by the two belt-like support plates 33, so that the built-in component can be easily assembled in the housing 3.

Now, referring back to FIG. 1, the light source unit 15 is provided with auxiliary reflecting mirrors 40 that reflect light traveling in the longitudinal direction at both ends of the LED unit 25. By the reflection of light in the longitudinal direction by the auxiliary reflecting mirror 40, the irradiation range in the longitudinal direction is expanded.
Further, a fine groove (not shown) for imparting a diffusing component to the reflected light is formed on the reflecting surface 27 of each reflector 29, whereby uneven irradiation at the condensing point (second focal point F2) is formed. Is to be reduced.
At this time, by forming the fine groove parallel to the longitudinal direction of the reflecting surface 27 (the arrangement direction of the LEDs 16), the irradiation area of the irradiation area F2 can be expanded in the width direction indicated by the arrow X in FIG. Further, by forming a groove perpendicular to the longitudinal direction of the reflecting surface 27, the irradiation area of the irradiation area F2 can be expanded in the length direction indicated by the arrow Y in FIG.

As described above, according to the present embodiment, the LED unit 25 is provided on both surfaces of the end portion of the steel plate 30 as a heat conductive plate having thermal conductivity, and the reflector 29 having the reflective surface 27 is formed on the LED. The light source unit 15 is provided for each unit 25, the heat radiating plate 19 is provided on the steel plate 30 extending from the light source unit 15, and the heat of the light source unit 15 is radiated from the heat radiating plate 19.
With this configuration, since the light source unit 15 includes the two LED units 25, the ultraviolet irradiation intensity can be increased, and the heat generated by the LED units 25 is provided outside the light source unit 15 via the steel plate 30. Therefore, good heat dissipation of the LED unit 25 can be obtained.
As a result, since the ultraviolet irradiation intensity is increased, the time required for ink curing can be shortened, and the improvement in heat dissipation can extend the life of the LED 16 and improve the luminous flux maintenance factor.

  In addition, according to the present embodiment, the mounting substrate 23 of the two LED units 25 is sandwiched between the pair of reflectors 29, and the reflector 29 and the steel plate 30 are screwed and fixed together. Since the relative position between the reflecting surface 27 of the reflector 29 and the LED unit 25 is uniquely determined as the 29 is fixed, the LED 16 can be easily and accurately positioned at a predetermined position with respect to the reflecting surface 27. As a result, the assembly is improved.

  Moreover, according to this embodiment, since it is set as the structure which fixes the control board 17 to the said steel plate 30, built-in components, such as the light source part 15, the control board 17, and the heat sink 19, are assembled | attached to the steel plate 30 and unitized. Thus, the handling is facilitated, and the positions of the built-in components are determined based on the steel plate 30. Therefore, the positioning of the built-in components is facilitated.

Moreover, according to this embodiment, since the light source part 15 was set as the structure provided with the auxiliary | assistant reflective mirror 40 arrange | positioned at each of the both ends of the LED unit 25, it is to the longitudinal direction (array direction of LED16) by this auxiliary | assistant reflective mirror 40. The irradiation range in the longitudinal direction is expanded by the reflection of the light.
In addition, according to the present embodiment, since the fine grooves for imparting the diffusion component to the reflected light are formed on the reflection surface 27 of each reflector 29, the irradiation unevenness at the condensing point is reduced.

  The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.

  For example, in the above-described embodiment, the arrangement position of the LEDs 16 of each LED unit 25 is arranged slightly shifted from the first focal point F1 of the reflecting surface 27, and the depth at the condensing point (second focal point F2) is increased. You may make it do. Thereby, even when the recording surface of the recording medium slightly fluctuates above and below the condensing point, the ultraviolet intensity on the recording surface can be maintained at the intensity necessary for curing the ultraviolet curable ink.

  In addition, for example, in the above-described embodiment, an ultraviolet LED that emits light having a wavelength of 365 nm is used as the LED 16. Can be used.

  Further, for example, in the above-described embodiment, a configuration in which cooling air is applied to the heat radiating plate 19 and air cooling is illustrated, but the configuration is not limited thereto, and the heat radiating plate 19 may be water cooled.

It is a figure which shows the front surface, plane, bottom surface, right side surface, and left side surface of the LED irradiation apparatus which concerns on embodiment of this invention. It is a figure which shows typically the internal structure of a LED irradiation apparatus. It is a figure which expands and shows a light source part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED irradiation apparatus 3 Case 9 Intake fan 11 Exhaust port 13 Irradiation opening 15 Light source part 16 LED
17 Control Board 19 Heat Dissipation Plate 21 Heat Dissipation Fin 23 Mounting Board 25 LED Unit 27 Reflecting Surface 29 Reflector 30 Steel Plate (Heat Conduction Plate)
40 Auxiliary reflector

Claims (3)

The LED units are arranged in rows a plurality of LED on a substrate, provided on both surfaces of the end portions of the heat conductive plate having thermal conductivity, a pair of reflectors forming a reflecting surface of each of the LED unit substrate Sandwiched between and fixed to the heat conducting plate to constitute a light source unit,
A heat dissipating member is fixed to one surface of the heat conducting plate extending from the light source unit to dissipate heat of the light source unit from the heat dissipating member , and a control board including an LED drive circuit is disposed on the other surface of the heat conducting plate as a spacer. An LED irradiation apparatus comprising a fan that is fixed with a fan interposed therebetween and that blows cooling air to the side of the heat conducting plate . 2. The LED irradiation apparatus according to claim 1 , wherein the light source unit includes auxiliary reflecting mirrors disposed at both ends of the LED unit. LED illumination apparatus according to claim 1 or 2, characterized in that the groove is formed to diffuse the reflected light on the reflecting surface of the reflector.

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