JP5271849B2 - LED irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED irradiation device which secures an ultraviolet light amount necessary for ink curing even by a low output. <P>SOLUTION: In the LED irradiation device 1 which is equipped with LEDs 6 for irradiating ultraviolet rays and cures the ink by illuminating the ink printed on a recording medium with ultraviolet rays by the LEDs 6, a plurality of the LEDs 6 are arranged on a substrate 8 in an array in a feed direction so that a peak illuminance becomes almost flat continuously in the feed direction of the recording medium. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

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.

In general, in a printing press used for flat printing or the like, ultraviolet curable ink is used as a kind of ink (including ink, hereinafter simply referred to as ink) on the printing surface of a recording medium that is held and conveyed by a conveyance chain or the like. Printing is known. In this type of printing machine, in order to dry the ultraviolet curable ink, the ultraviolet ray curable ink is cured by irradiating light such as a metal halide lamp or a mercury lamp on the printing surface being transported immediately after printing. An ultraviolet curing drying device to be closely attached is used (see, for example, Patent Document 1). In such an ultraviolet curing drying apparatus, after the ultraviolet curable ink has landed on the recording medium, it is rapidly photocured. For this purpose, a high output and relatively large light irradiation apparatus is required. Has been.
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 (for example, see Patent Document 2).

Japanese Patent No. 3936780 JP 2002-93227 A

By using 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, the size of the device can be reduced. However, the light output of the ultraviolet LED is smaller than that of the lamp-type light source. For this reason, in order to secure the amount of ultraviolet light necessary for ink curing, a large number of ultraviolet LEDs are required, and heat generation of the light source becomes a problem.
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an LED irradiation device that secures an ultraviolet light amount necessary for ink curing even at a low output.

In order to achieve the above object, the present invention comprises an LED that irradiates ultraviolet rays to an ink printed on a recording medium by the LEDs, and cures the ink. A plurality of the LEDs are arranged in a row in the feed direction so that the peak illuminance continuously becomes substantially flat in the feed direction of the recording medium, and a cooling fluid passage for cooling the LEDs extends over the row of LEDs. A cooling jacket formed on the back side of the substrate, and a heat dissipating fin that is exposed to the flow path and radiates heat of the substrate along the flow direction of the cooling fluid. provided, the heat radiating fins are arranged in a width direction of the substrate, is formed by an outer fin member located outermost, and a plurality of central fin member located in the center, the central Fi Member, the small thickness than the outer fin member, characterized in that it is arranged closely spaced.

  Further, in the above configuration, the plurality of substrates are arranged adjacent to each other in the flow direction of the cooling fluid, and the heat radiating fins are recessed toward the substrate at positions corresponding to adjacent portions of the substrate. A groove may be formed.

The present invention also includes an LED that irradiates ultraviolet rays to an ink printed on a recording medium by the LED, and cures the ink in the LED irradiation device that cures the ink in a feeding direction of the recording medium. A cooling jacket in which a plurality of the LEDs are arranged in a row in the feed direction so that the peak illuminance is continuously flat, and a cooling fluid channel for cooling the LEDs is formed across the LEDs. A plurality of the substrates are disposed on the back surface of the substrate, and provided on the cooling jacket on the substrate side, along the flow direction of the cooling fluid, are provided with radiating fins that are exposed to the flow path and radiate heat of the substrate. Are disposed adjacent to each other in the flow direction of the cooling fluid, and the radiating fin is provided with a groove recessed toward the substrate at a position corresponding to an adjacent portion of the substrate. To.

  Moreover, the said structure WHEREIN: The said fin member may be arrange | positioned so that a space | interval may be so narrow as the center part.

  Moreover, the said structure WHEREIN: The said fin member may be formed so that thickness is so thin that the center part.

  According to the present invention, since a plurality of LEDs are arranged in a row in the feed direction so that the peak illuminance is continuously flat in the feed direction of the recording medium on the substrate, the ink is irradiated with ultraviolet rays for a relatively long time. Therefore, it is effective for the ink curing reaction, and the amount of ultraviolet light necessary for ink curing can be secured even at a low output.

It is a figure which shows the plane of the LED irradiation apparatus concerning this Embodiment of this invention, a front surface, a back surface, and a side surface. It is a perspective view which shows the internal structure of a LED irradiation apparatus from one end side. It is a figure which expands and shows a part of FIG. It is a perspective view which shows the internal structure of LED irradiation apparatus from the side. It is the figure which shows the back surface of a cooling jacket main body, and the perspective view which shows a cooling jacket main body from one end side. It is a figure which shows the front and side surface of a LED board. It is a figure which shows the ultraviolet illumination intensity of a LED irradiation apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a plane, a front surface, a back surface, and a side surface of an LED irradiation apparatus according to an embodiment of the present invention.
The LED irradiation device 1 is an irradiation device that is used in a recording device and irradiates the ink recorded on a recording medium by the recording device with ultraviolet rays to cure the ink. As shown in FIG. 1, the LED irradiation apparatus 1 has an elongated box-shaped casing 2 extending to a length corresponding to the width of the recording medium. The casing 2 includes a front plate 2A and a back plate 2B. A side plate 2C on one end extending in the longitudinal direction, another side plate 2D on the other end extending in the longitudinal direction, and a pair of side plates 2E extending in the width direction (vertical direction in the drawing showing the front of FIG. 1). It is prepared for. The front plate 2A is provided with an irradiation opening 4 that is opened in a long and narrow rectangular shape in the longitudinal direction. The irradiation opening 4 is covered with a front glass 4A made of, for example, quartz glass that is transparent to ultraviolet rays, and a plurality (14 in the present embodiment) including a large number of LEDs 6 inside the front glass 4A. LED substrates (substrates) 8 are adjacently arranged in a line, and a planar light source for irradiating planar light is configured.

A box-shaped metal control box 10 shorter than the length of the housing 2 is attached to the back plate 2B of the housing 2. On one side surface 10 </ b> A on one end side that extends in the longitudinal direction of the control box 10, a through hole 12 through which a cable passes is provided.
The control box 10 is provided with a plurality of protective bars 14 (seven in the present embodiment) in the longitudinal direction that prevent the front glass 4A from being stained by ink. The protection bar 14 extends from the one side surface 10 </ b> A of the control box 10 to the other side surface 10 </ b> B on the other end side that extends around the front plate 2 </ b> A of the housing 2 and extends in the longitudinal direction of the control box 10. As shown in the front view of FIG. 1, the protection bar 14 is provided at a predetermined angle with respect to the recording medium feeding direction (vertical direction in the front view). Irradiation unevenness of the recording medium due to shadows can be suppressed. Further, as shown in the side view of FIG. 1, the protection bar 14 includes a protruding portion 14A that protrudes toward one end side, and this protruding portion 14A has a predetermined angle with respect to the one side plate 2C. It has an inclined portion 14B that is inclined. Since the recording medium is guided along the inclined portion 14B at the time of conveyance, the recording medium is prevented from floating and contacting the LED irradiation device 1 at the time of conveyance. The protection bar 14 is appropriately mounted depending on the intended use, and adjusts the irradiation distance to the recording medium and also plays the role of adjusting the smooth flow of the recording medium.
As shown in the rear view of FIG. 1, a pair of folding handles 16 that are used when the LED irradiation device 1 is transported are provided on the rear surface 10 </ b> C of the control box 10.

2 is a perspective view showing the internal configuration of the LED irradiation apparatus 1 from one end side, and FIG. 3 is an enlarged view of a part of FIG. FIG. 4 is a perspective view showing the internal structure of the LED irradiation device 1 from the side (the side of the drawing showing the side surface of FIG. 1). FIG. 5 is a view showing the back surface of the cooling jacket body and a perspective view showing the cooling jacket body from one end side.
As shown in FIGS. 2 and 3, a plurality (14 in the present embodiment) of drive boards 18 are provided in the control box 10 at positions corresponding to the LED boards 8. Each drive board 18 includes a pair of connectors 18A on one end side and the other end side. A plurality (three in the present embodiment) of terminal blocks 22 are attached to the plurality of drive boards 18.

  In the housing 2, an LED substrate 8 is provided on the front surface. The LED board 8 includes a pair of connectors 8A on one end side and the other end side, respectively, and these connectors 8A extend to the back side. As shown in FIG. 4, each connector 8 </ b> A is connected to each connector 18 </ b> A of the drive board 18 by a connection cable 24. That is, the LED board 8 and the drive board 18 are connected by four connection cables 24, and these constitute one module 26. Therefore, as shown in FIG. 2, the LED irradiation device 1 includes 14 modules 26. Note that the number of modules 26 may be one or more.

A cooling jacket 30 for cooling the LED substrate 8 is provided on the back surface of the LED substrate 8. The cooling jacket 30 includes a box-shaped cooling jacket main body 32 that opens the back side, and a cooling jacket lid 34 that covers the open portion of the cooling jacket main body 32 and forms the back plate 2B of the housing 2. . An O-ring is disposed between the cooling jacket body 32 and the cooling jacket lid 34, and the cooling jacket body 32 and the cooling jacket lid 34 are sealed.
The cooling jacket body 32 and the cooling jacket lid 34 are made of a metal having high thermal conductivity such as copper, for example. Further, the front plate 2A, the one side plate 2C, the other side plate 2D, and the pair of side plates 2E of the housing 2 that cover the cooling jacket 30 are formed of, for example, aluminum to protect the cooling jacket 30.

The cooling jacket main body 32 is fixed in close contact with the front plate 2A of the housing 2, and the heat of the LED 6 (see FIG. 1) conducted to the front plate 2A is easily conducted to the cooling jacket main body 32. Heat can be dissipated more effectively.
The LED substrate 8 is fixed in close contact with the cooling jacket main body 32, and the drive substrate 18 is fixed in close contact with the cooling jacket lid 34. Here, silicon is applied to the LED substrate 8 as a member having good thermal conductivity. When the LED substrate 8 is fixed to the cooling jacket main body 32, the LED substrate 8 and the cooling jacket main body 32 In between, silicon is filled. That is, the heat of the LED 6 is easily conducted to the cooling jacket main body 32 through the silicon, and the heat of the LED 6 can be radiated more effectively. Further, silicon is also applied to the drive substrate 18, and the heat of the drive substrate 18 is effectively radiated to the cooling jacket lid 34 through the silicon.

At both ends in the longitudinal direction of the cooling jacket lid 34, a water supply port 36 for supplying a cooling fluid into the cooling jacket 30 and a water return port 38 for discharging the cooling fluid in the cooling jacket 30 to the outside. Are formed respectively. That is, a flow path F through which a cooling fluid flows from the water supply port 36 to the water return port 38 is formed in the cooling jacket 30, and the cooling fluid flows from the water supply port 36 as indicated by an arrow in FIG. 2. It circulates to the water return port 38. The flow path F is formed to be longer than the arrangement length of the LED substrate 8 and the drive substrate 18, and the LED conducted to the cooling jacket main body 32 and the cooling jacket lid 34 by circulating the cooling fluid in the flow path F. The heat of the substrate 8 and the drive substrate 18 is conducted to the cooling fluid.
As shown in FIG. 4, one end portion of the cooling jacket main body 32 that forms the flow path F is formed with one recess 32 </ b> A that is recessed on one end side, and the other end side faces the recess 32 </ b> A on the other end side. The other recessed part 32B dented in is formed.

The cooling jacket body 32 is provided with heat radiating fins 40 exposed to the flow path F. A plurality of (six in this embodiment) central fin members that extend in the longitudinal direction of the housing 2 are arranged in the central portion of the cooling jacket main body 32 in the width direction (vertical direction in FIG. 4). 41 and a pair of outer fin members 42 arranged in parallel with the central fin member 41 interposed therebetween. The central fin member 41 is formed with a relatively small thickness (for example, 3 mm), and the outer fin member 42 is formed with a relatively thick thickness (for example, 4 mm). The central fin member 41 is disposed at substantially the same interval δ (for example, 3 mm) in the width direction of the cooling jacket main body 32, and the outer fin member 42 is larger than the interval δ between the cooling jacket main body 32 and the central fin member 41. (For example, 4 mm).
As shown in FIGS. 2 and 5, grooves 41 </ b> A and 42 </ b> A that are recessed toward the LED substrate 8 are formed in the fin members 41 and 42 at positions corresponding to adjacent portions of the LED substrate 8.

FIG. 6 is a view showing the front and side surfaces of the LED substrate 8. FIG. 7 is a diagram illustrating the relationship between the ultraviolet illuminance and the irradiation width of the LED irradiation apparatus 1. FIG. 7 shows the relationship between the ultraviolet illuminance and the irradiation width at a position where the irradiation distance from the LED 6 is relatively short (for example, 10 mm).
As shown in FIG. 6, the LED substrate 8 has an insulating substrate 8B, a metal plate 8C, and a width direction in which the LED substrate 8 is sandwiched and fixed between the insulating substrate 8B and the metal plate 8C (vertical direction in FIG. 6). A pair of metal plates 8D is provided. Since the LED 6 is disposed on the insulating substrate 8B, the insulating substrate 8B is formed of a polymer resin or a heat-resistant polymer resin containing inorganic powder or inorganic fibers. On the other hand, the metal plate 8 </ b> C and the metal plate 8 </ b> D are formed of a high thermal conductivity material such as copper, and the LED substrate 8 has a function of radiating heat generated from the LED 6.

  Each LED board 8 includes a plurality (630 in the present embodiment) of LEDs 6, and the output of each LED board 8 is, for example, about 500W. Each LED 6 is, for example, an ultraviolet LED that emits light having a wavelength of 375 nm. These LEDs 6 are arranged in a grid pattern (30 × 21), and the arrangement interval of the LEDs 6 is set so that the ultraviolet illuminance distribution of the entire LED 6 is substantially uniform. The LEDs 6 are arranged over the length L of the LED substrate 8 and are arranged in a row so that the arrangement width W in the width direction becomes longer.

  In this manner, the LEDs 6 are arranged in a row so that the ultraviolet illuminance distribution is uniform and the array width W in the width direction of the LED substrate 8, that is, the recording medium feeding direction is long. As shown in FIG. 7, the peak illuminance of the LED irradiating device 1 is continuously flattened. Thereby, in the LED irradiation apparatus 1, since the irradiation time of ultraviolet rays becomes longer compared with the case where the array width in the width direction of the LEDs is shortened and ultraviolet rays are instantaneously irradiated, the amount of ultraviolet light necessary for ink curing is reduced even at low output. It can be secured. Therefore, since a large cooling capacity is not required, the cooling jacket 30 can be reduced in size, and the LED substrate 8 with an output of 500 W can be cooled even if, for example, tap water is used as the cooling fluid.

In the present embodiment, the cooling fluid that absorbs the heat of the LED 6 and is discharged from the water return port 38 is cooled by, for example, a cooling device, and then supplied to the water supply port 36 and circulated again. In this configuration, the output of the LED substrate 8 is kept low, and the temperature of the necessary cooling fluid may be about room temperature (for example, 22 ° C.), so the LED irradiation device 1 does not require a countermeasure against condensation, and the configuration Simplify. The cooling fluid discharged from the water return port 38 may be discarded without being circulated.
As shown in FIGS. 2 and 4, the flow path F is formed along the surface of the LED substrate 8, and the width H of the flow path F connecting the recesses 32 </ b> A and 32 </ b> B is equal to the array width W of the LEDs 6. It is almost the same. For this reason, since the cooling fluid circulates along the surface of the LED substrate 8 with the arrangement width W of the LEDs 6, all the LEDs 6 can be cooled.

  When a plurality of LEDs 6 are arranged in a grid and the cooling fluid is circulated in the longitudinal direction of the cooling jacket 30, the LED 6 located at the center in the width direction of the LED substrate 8 has a higher temperature. There exists a possibility that irradiation efficiency may fall, so that LED6 becomes high. Therefore, in the present embodiment, a thin central fin member 41 is disposed at the center of the cooling jacket 30 in the width direction, and a thick outer fin member 42 is disposed on the outer side in the width direction. The interval d at which the member 42 is disposed is larger than the interval δ at which the central fin member 41 is disposed. For this reason, since cooling efficiency becomes high as the center part of the LED board 8, the LEDs 6 can be cooled substantially uniformly in the width direction of the LED board 8.

Furthermore, since the fin members 41 and 42 are formed with grooves 41A and 42A that are recessed toward the LED substrate 8 at positions corresponding to the adjacent portions of the LED substrate 8, cooling is performed near the adjacent portions of the LED substrate 8 having a high thermal resistance. Since the fluid can be circulated and adjacent portions can be more effectively cooled, the entire plurality of LED substrates 8 can be cooled substantially uniformly.
As described above, the LED substrate 8 is cooled substantially uniformly, so that the irradiation efficiency of the LED 6 can be made uniform, and as a result, the ink printed on the recording medium can be cured substantially uniformly.
In the present embodiment, each LED board 8 is connected to and controlled by any one of a plurality (three) of terminal blocks 22, and the plurality (14) of LED boards 8 are divided into three blocks. Therefore, the LED board 8 can be replaced for each block during maintenance.

  As described above, according to the present embodiment, a plurality of LEDs 6 are arranged on the LED substrate 8 in a row in the feed direction so that the peak illuminance is continuously flat in the feed direction of the recording medium. Since the ink is irradiated with ultraviolet rays for a relatively long time, it is effective for the ink curing reaction, and the amount of ultraviolet light necessary for ink curing can be secured even at low output.

  Moreover, according to this Embodiment, the cooling jacket 30 which forms the flow path F of the cooling fluid which cools LED6 over the arrangement width W of LED6 is arrange | positioned in the back surface of LED board 8, and LED board 8 side is provided. Since the radiation fins 40 that are exposed to the flow path F and radiate the heat of the LED substrate 8 are provided in the cooling jacket 30 along the flow direction of the cooling fluid, sufficient heat radiation is obtained.

  Further, according to the present embodiment, a plurality of LED substrates 8 are arranged adjacent to each other in the flow direction of the cooling fluid, and the LED is disposed at a position corresponding to the adjacent portion of the LED substrate 8 on the radiation fin 40. The grooves 41A and 42A that are recessed toward the substrate 8 are formed. For this reason, since the cooling fluid can be circulated near the adjacent portion of the LED substrate 8 having a high thermal resistance to cool the adjacent portion more effectively, the entire plurality of LED substrates 8 can be cooled substantially uniformly.

  Further, according to the present embodiment, the radiating fin 40 is formed by arranging a plurality of fin members 41 and 42, and the central fin member 41 located in the center is spaced from the outer fin member 42 located outside. The configuration is such that it is arranged narrowly and is thinner than the outer fin member 42. Thus, since the central fin member 41 is formed so as to have a surface area larger than that of the outer fin member 42, the cooling efficiency becomes higher in the central portion of the LED substrate 8. Can be cooled.

However, the above embodiment is an aspect of the present invention, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.
For example, in the above-described embodiment, an ultraviolet LED that emits light having a wavelength of 375 nm is used as the LED 6, but the LED 6 is not limited to this, and an LED that emits optimal light according to the type of the photocurable material to be cured is used. Can be used.
Moreover, in the said embodiment, although LED6 was arrange | positioned in the grid | lattice form so that it might become a row | line | column in a feed direction, if not only this but a row | line | column in a feed direction, you may arrange | position in zigzag form, for example. .

Moreover, in the said embodiment, although the arrangement | sequence width W of LED6 became the irradiation width of LED irradiation apparatus 1, the irradiation width of the width direction is changed by comprising so that lighting of LED6 may be controlled separately. You may do it. In this case, it is only necessary to turn on the LED 6 having a width that can obtain the amount of ultraviolet light necessary for curing the ink.
Further, in the above embodiment, the plurality of central fin members 41 are arranged at substantially the same interval δ and formed with substantially the same thickness, but the fin members located at the central part are formed thinner, And the interval may be arrange | positioned so narrowly that the fin member located in a center part.
Furthermore, in the said embodiment, although the LED board 8 was provided with two or more, one piece may be sufficient. In this case, it is not necessary to provide the grooves 41A and 42A in the fin members 41 and 42.

1 LED irradiation device 6 LED
8 LED board (board)
30 Cooling jacket 40 Radiating fin 41 Central fin member 42 Outer fin member 41A, 42A Groove F Flow path δ interval d interval

Claims (3)

In an LED irradiation apparatus that includes an LED that irradiates ultraviolet light, irradiates the ink printed on the recording medium with this LED with ultraviolet light, and cures the ink.
On the substrate, a plurality of the LEDs are arranged in a row in the feed direction so that peak illuminance is continuously flat in the feed direction of the recording medium,
A cooling jacket for forming a cooling fluid flow path for cooling the LEDs across the LED rows is disposed on the back surface of the substrate;
Provided in the cooling jacket on the substrate side along the flow direction of the cooling fluid is a radiation fin that is exposed to the flow path and dissipates heat of the substrate.
The heat dissipating fins are arranged in the width direction of the substrate, and are formed by an outer fin member positioned at the outermost portion and a plurality of central fin members positioned at the center ,
The said center fin member is thinner than the said outer side fin member, and the LED irradiation apparatus characterized by the space | interval being arrange | positioned narrowly . A plurality of the substrates are arranged adjacent to each other in the flow direction of the cooling fluid;
2. The LED irradiation apparatus according to claim 1, wherein a groove that is recessed toward the substrate is formed at a position corresponding to an adjacent portion of the substrate in the radiation fin. In an LED irradiation apparatus that includes an LED that irradiates ultraviolet light, irradiates the ink printed on the recording medium with this LED with ultraviolet light, and cures the ink.
On the substrate, a plurality of the LEDs are arranged in a row in the feed direction so that peak illuminance is continuously flat in the feed direction of the recording medium,
A cooling jacket for forming a cooling fluid flow path for cooling the LEDs across the LED rows is disposed on the back surface of the substrate;
Provided in the cooling jacket on the substrate side along the flow direction of the cooling fluid is a radiation fin that is exposed to the flow path and dissipates heat of the substrate.
A plurality of the substrates are arranged adjacent to each other in the flow direction of the cooling fluid;
An LED irradiation apparatus, wherein a groove that is recessed toward the substrate is formed at a position corresponding to an adjacent portion of the substrate in the heat radiation fin.

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