JP2009061702A - Ultraviolet irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet irradiation apparatus which prevents a gradual decease of a light amount in the vicinity of both end areas irradiated with ultraviolet rays so as to enable even both end areas to be utilized. <P>SOLUTION: In a light emitting module 1, a diode chip having an emission wavelength being in an ultraviolet ray area is built in a package. An appliance body 2 holds a plurality of light emitting modules 1 side by side. At both ends in the longitudinal direction of the appliance body 2, mounting bases 21 are formed which are inclined so as to approach a printing object toward the ends in the longitudinal direction of the appliance body 2. The light emitting modules 1 arranged at both ends in the longitudinal direction of the appliance body 2 are mounted to the mounting bases 21. The amount of the ultraviolet ray irradiated from an ultraviolet irradiation apparatus 30 is not gradually attenuated but sharply decreased at both ends. Thus, the light amount becomes almost constant up to vicinities of both ends of the appliance body 2, so that the ultraviolet rays at both the ends become available. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultraviolet irradiation device that cures ultraviolet curable ink using a light emitting diode having an emission wavelength in the ultraviolet region.

  Conventionally, various ink jet printing apparatuses using ink that is cured by irradiation with ultraviolet rays have been proposed. In this type of inkjet printing apparatus, an ultraviolet irradiation device that irradiates ultraviolet rays is provided adjacent to a print head that ejects ink. Since ink jet printing apparatuses are often used for color printing, they use ink of four colors (cyan, magenta, yellow, black) or more, and an independent print head is provided for each ink.

  In addition to the use of a discharge lamp such as a xenon lamp as a light source, the ultraviolet irradiation device has been proposed to use a light emitting diode having an emission wavelength in the ultraviolet region as a light source (see, for example, Patent Document 1).

  In the inkjet printing apparatus described in Patent Document 1, a configuration in which an ultraviolet irradiation device is disposed adjacent to each print head is disclosed. Patent Document 1 discloses a configuration in which a print target is transported in one direction, a plurality of print heads are arranged in a direction orthogonal to the transport direction of the print target, and the print head is reciprocated in that direction. And a configuration in which print heads are arranged along the conveyance direction of the print object.

  In the former configuration, a print head is disposed between two ultraviolet irradiation devices in a direction in which the print head reciprocates, and an ultraviolet irradiation device is disposed between adjacent print heads. Accordingly, each print head is disposed between two ultraviolet irradiation devices. In this configuration, when the print head is reciprocated, ink is ejected from the print head to the print object in the forward path and the return path, and immediately after the ink is ejected from the print head to the print object, the ultraviolet irradiation device applies the ultraviolet light to the print object. Can be applied to cure the ink.

In the latter configuration, the print head and the ultraviolet irradiation device are alternately arranged in the direction in which the print object is conveyed, and immediately after the ink is ejected from the print head to the print object, the ultraviolet light is applied from the ultraviolet irradiation device to the print object. To cure the ink.
JP 2004-160925 A

  By the way, in the structure described in patent document 1, the ultraviolet irradiation apparatus wider than the width | variety of the area | region which ejects ink in a print head is required. This is because, in an ultraviolet irradiation device using light emitting diodes, a large number of light emitting diodes are arranged to secure the ultraviolet intensity necessary for curing the ink, and the entire area of the printing object where the ink is deposited This is because it is required to uniformly irradiate ultraviolet rays over the entire area.

  In general, when a large number of light emitting diodes are arranged on a straight line, even if the luminances of the respective light emitting diodes are equal, the amount of light at the both ends of the region irradiated with light on the printing object is lower than that at the center. In other words, the light emitting diodes are adjacent to both sides at the center, whereas the light emitting diodes are adjacent to only one side at both ends, so that the amount of light decreases at both ends. If an area where the amount of light decreases is used, unevenness of ink curing occurs. Therefore, in the technique described in Patent Document 1, the ultraviolet irradiation device is formed wider than the print head, and the area where the amount of light decreases. Not to use.

  The present invention has been made in view of the above-mentioned reasons, and the object thereof is to make it possible to use ultraviolet rays near both ends without waste by suppressing a decrease in the amount of light near both ends of a region irradiated with light. Another object of the present invention is to provide an ultraviolet irradiation device that can be miniaturized.

  The invention according to claim 1 is an ultraviolet irradiation device for curing an ultraviolet curable ink by irradiating the ultraviolet curable ink applied to an object to be printed with an ultraviolet ray, wherein the light emitting diode chip having an emission wavelength in the ultraviolet region is packaged. A light emitting module built in the apparatus, an instrument body that holds a plurality of light emitting modules that move relative to the printing object and are arranged in a direction perpendicular to the direction of relative movement, and ultraviolet light of the printing object. A light distribution adjusting element that adjusts the light distribution of the light emitting modules at both ends so that the intensity of ultraviolet rays is constant over the entire length in the direction orthogonal to the direction of relative movement of the print object in the region being It is characterized by.

  According to a second aspect of the present invention, in the first aspect of the invention, the light distribution adjusting element is constituted by the instrument main body, and the instrument main body is adjacent to the light emitting modules at both ends of the light emitting modules in the direction of maximum intensity. It is characterized by comprising a mounting base that is attached so as to tilt toward another light emitting module.

  In the invention of claim 3, in the invention of claim 1, the light distribution adjusting element is a refractive optical system disposed in front of the light emitting modules at both ends of the light emitting modules and held by the instrument body, The optical system is characterized in that the area irradiated with the light emitted from the light emitting module is changed so as to approach the area irradiated with the light emitted from another adjacent light emitting module.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the light distribution adjusting element is a reflective optical system disposed in front of the light emitting modules at both ends of the light emitting modules and held by the instrument body, The optical system is characterized in that the area irradiated with the light emitted from the light emitting module is changed so as to approach the area irradiated with the light emitted from another adjacent light emitting module.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the light emitting modules at both ends of the light emitting module have a larger light output than other light emitting modules.

  According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the light emitting module has a higher arrangement density at both ends than at the central portion.

  According to the configuration of the invention of claim 1, the light distribution of the light emitting modules at both ends in the direction orthogonal to the direction of moving relative to the print object in the region irradiated with ultraviolet rays in the print object is provided. By providing the light distribution adjusting element to be adjusted, the intensity of the ultraviolet ray is kept constant over the entire length in the direction, so that the ultraviolet ray can be utilized without difficulty to both ends of the light irradiation region. In other words, in the region irradiated with ultraviolet rays, the amount of light does not decrease even at both end portions, and the same amount of light as the central portion can be secured. Further, the ultraviolet rays are hardly irradiated outside the irradiation region, and the ultraviolet rays can be used without waste. This leads to a reduction in the number of light emitting modules or a reduction in size.

  According to the configuration of the second aspect of the present invention, only the mounting base for adjusting the mounting direction of the light emitting module with respect to the fixture body is provided, and the configuration is simple without requiring a separate member. That is, the number of parts is small and it can be provided at low cost.

  According to the configuration of the invention of claim 3, since the light distribution is controlled by providing the refractive optical systems in front of the light emitting modules at both ends, any optical design related to the refractive optical system and the arrangement of the light emitting modules can be used. Light distribution design becomes possible.

  According to the configuration of the invention of claim 4, since the light distribution is controlled by providing the reflecting optical systems in front of the light emitting modules at both ends, any optical design regarding the reflecting optical system and the arrangement of the light emitting modules can be used. Light distribution design becomes possible.

  According to the configuration of the invention of claim 5, light emitting modules having different light outputs are required, but by making the light outputs of the light emitting modules at both ends larger than the light outputs of the other light emitting modules, It is possible to more reliably reduce the decrease in light output. By combining this configuration with other configurations, a higher effect can be expected.

  According to the configuration of the invention of claim 6, since the arrangement density of the light emitting modules is made different between the both end portions and the central portion and the arrangement density of both end portions is set high, the light emitting modules having a large light output are arranged at both end portions. The same effect as that of the invention of claim 5 can be expected.

  In the embodiment described below, an example in which the ultraviolet irradiation device 30 is used in the printing apparatus having the configuration shown in FIG. 4 is shown. That is, the printing apparatus follows the conveyance direction of the print object 20 with respect to the print object 20 such as paper conveyed in one direction (the arrow X direction in FIG. 4) by a conveyance mechanism (not shown). Four print heads 31 are arranged, and an ultraviolet irradiation device 30 is arranged on the downstream side of each print head 31 in the conveyance direction of the print object 20.

  The print head 31 ejects ultraviolet curable ink (hereinafter simply referred to as “ink”) by an inkjet method, and in the illustrated example, four print heads 31 for magenta, cyan, yellow, and black are used. Is assumed. However, it is also possible to use inks of other colors, and the printing apparatus can be configured to use five or more print heads 31. The print head 31 has a length dimension capable of ejecting ink over substantially the entire length of the print object 20 in the width direction (the arrow W direction in FIG. 4). In general, the area where the ink ejected from the print head 31 adheres to the print object 20 is set wider than the width of the print object 20.

  The ultraviolet irradiation device 30 irradiates the printing object 20 with ultraviolet rays in the width direction of the printing object 20 with a width equal to or slightly wider than the area where the ink ejected from the print head 31 adheres to the printing object 20. Since the ultraviolet irradiation device 30 is arranged for each print head 31 on the downstream side in the transport direction of the print target 20, the ink ejected from the print head 31 is irradiated with ultraviolet rays from the ultraviolet irradiation device 30, Hardens immediately. In other words, after the inks of the respective colors are cured, the inks of the other colors adhere to the print target 20, so that different color inks are not mixed and the color does not become cloudy.

  The printing apparatus is not limited to the above-described configuration, and a configuration in which the print object 20 is fixed at a fixed position and the print head 31 and the ultraviolet irradiation device 30 move together, or the print object 20 is in one direction. Even if the print head 31 and the ultraviolet irradiation device 30 are transported and arranged in the width direction of the print object 20 and reciprocate in the width direction of the print object 20, the present invention described below will be described. The technology can be applied. In the following embodiments, the configuration of the ultraviolet irradiation device 30 will be described in detail.

(Embodiment 1)
As shown in FIG. 1, the ultraviolet irradiation device 30 is configured by attaching a plurality of light emitting modules 1 to an instrument body 2. As shown in FIG. 2, each light emitting module 1 has a configuration in which a plurality of light emitting diode chips 11 are housed in a package 10, and the light emitting diode chips 11 housed in the package 10 are connected to each other (for example, A series circuit in which four 16 light emitting diode chips 11 are connected in series is connected in parallel, or 16 light emitting diode chips 11 are connected in parallel). The light emitting diode chip 11 has a light emission wavelength in the ultraviolet region.

  The package 10 includes a base substrate 12 made of a metal plate on which the light-emitting diode chip 11 is placed, a cover substrate 13 made of a metal plate surrounding a portion of the base substrate 12 on which the light-emitting diode chip 11 is placed, and a base substrate 12. Between the base substrate 12 and the cover substrate 13 and an insulating material layer 14 that insulates the cover substrate 13 from each other. The base substrate 12 and the cover substrate 13 are made of copper alone or a copper alloy.

  The lower surface electrode (for example, anode) of the light emitting diode chip 11 is directly connected to the base substrate 12 by die bonding, and the upper surface electrode (for example, cathode) of the light emitting diode chip 11 is connected to the cover substrate 13 by wire bonding. . That is, one electrode of the light emitting diode chip 11 is electrically connected to the base substrate 12, and the other electrode is electrically connected to the cover substrate 13.

  The cover substrate 13 is provided with an exposure hole 15 through which the light emitting diode chip 11 mounted on the base substrate 12 is exposed. The inner peripheral surface of the exposure hole 15 is inclined so as to increase the inner diameter of the exposure hole 15 as the distance from the base substrate 12 increases. A projection lens 16 is attached to the exposure hole 15.

  Therefore, the light emitting diode chip 11 is housed in a sealed space surrounded by the base substrate 12, the cover substrate 13, and the light projecting lens 16, and is shielded from environmental influences such as humidity. The light distribution of the light emitted from the light emitting diode chip 11 can be controlled by adjusting the position and characteristics of the light projecting lens 16 or the inclination angle and reflectance of the inner peripheral surface of the exposure hole 15.

  A flow path (not shown) is formed inside the package 10, and the temperature rise of the light emitting diode chip 11 is suppressed by flowing a cooling fluid through the flow path. Further, it is also possible to adopt a configuration in which a separately provided cooling device (water-cooled radiator, heat pipe, thermosiphon, Peltier element, etc.) is brought into contact without forming a flow path. By suppressing the temperature rise of the light emitting diode chip 11, it is possible to suppress a decrease in light emission efficiency. In particular, a high output is required to cure the ultraviolet curable ink, and it is necessary to apply a current of several A to several tens of A to the light emitting module 1, so that the light emitting module 1 must be cooled. However, in this embodiment, since the structure which cools the light emitting module 1 is not a summary, description is abbreviate | omitted.

  As shown in FIG. 1, the instrument main body 2 holds a plurality of light emitting modules 1 arranged in the width direction of the printing object 20. On the surface of the instrument main body 2 facing the printing object 20, mounts 21 as light distribution adjusting elements are formed at both ends in the longitudinal direction (that is, the width direction of the printing object 20). In the instrument main body 2, the part to which the light emitting module 1 is attached except for the mounting base 21 is a plane substantially parallel to the printing surface (the surface on which the ink is applied) of the printing object 20. The surface is inclined with respect to the printing surface of the printing object 20. That is, the tool body 2 is inclined so as to approach the printing surface of the printing object 20 from the center side toward the end side.

  When the light emitting module 1 is attached to the mounting base 21, the irradiation area of the ultraviolet light emitted from the light emitting module 1 is overlapped with the irradiation area of the adjacent light emitting module 1 compared to the case where the mounting base 21 is not provided. Displacement in the direction of increasing. That is, the spread of the entire irradiation region of the light emitting module 1 attached to the instrument body 2 is suppressed, and the decrease in the light amount at both ends is suppressed. 3A shows an example of the light amount distribution on the printing surface when the light emitting modules 1 at both ends are attached to the mounting base 21, and FIG. 3B shows the printing surface when the mounting base 21 is not provided. An example of the light amount distribution in FIG.

  (B) in FIG. 3 corresponds to the conventional configuration, and the amount of light gradually decreases at the end, so that this portion cannot be used for ultraviolet curing, whereas the configuration of this embodiment is adopted. Then, as shown in FIG. 3 (a), the amount of light sharply decreases at the end, making it possible to use ultraviolet rays that were not used conventionally, and as a result, the amount of light is constant compared to the conventional configuration. It turns out that a certain range was able to be expanded. In other words, while using the same number of light emitting modules 1, the region where the light amount is constant as compared with the conventional configuration is widened, and it is possible to deal with a wide print object 20. In other words, in the configuration of the present embodiment, the number of light emitting modules 1 required for the print object 20 having the same width can be reduced as compared with the conventional configuration.

  In the configuration of the present embodiment, the mounting base 21 is formed on the instrument body 2 and the direction of the maximum intensity of the light emitting modules 1 at both ends is merely inclined toward the other adjacent light emitting modules 1. Can be provided at low cost with a small number of parts.

(Embodiment 2)
In the present embodiment, as shown in FIG. 5, a light projecting lens 22 made of a cylindrical lens is attached to the instrument body 2. The light projecting lens 22 is arranged so that the longitudinal direction thereof coincides with the longitudinal direction of the instrument body 2. Unlike a normal cylindrical lens, the light projection lens 22 used in this example is provided with a condensing part 22a formed in a shape forming a part of a spherical surface at both ends in the longitudinal direction. This condensing part 22a functions as a light distribution adjusting element of the refractive optical system.

  The condensing part 22a is a part obtained by dividing a spherical surface having the same radius as the cylindrical lens into four parts, and the outer peripheral surface of the condensing part 22a and the outer peripheral surface of the cylindrical lens are smoothly continuous. The light emitting module 1 held by the fixture main body 2 is disposed so as to face the planar portion of the cylindrical lens, and the light emitting modules 1 at both ends are disposed closer to the end of the light projecting lens 22 than the center of the light collecting portion 22a. The That is, the condensing part 22a is arrange | positioned ahead of the light emitting module 1 of both ends.

  As shown in FIG. 6, the light emitted from the light emitting module 1 arranged in association with the light collecting unit 22a (indicated by the arrow) is emitted from another light emitting module 1 and is a region other than the light collecting unit 22a. It is refracted so as to approach the irradiation region of the ultraviolet rays that have passed through. Therefore, similarly to the configuration of the first embodiment, the light from the light emitting module 1 at the end is not diverged to the outside, the light amount is prevented from being gently attenuated, and the range where the light amount is constant can be widened. .

  In this embodiment, the condensing part 22a which consists of a part of spherical surface is formed, However, The shape of the condensing part 22a can be designed suitably, and light distribution will be changed if the shape of the condensing part 22a is changed. be able to. The light distribution also changes depending on the positional relationship between the light emitting module 1 and the light projecting lens 22. Therefore, as compared with the configuration in which only the inclination angle of the mounting base 21 is an adjustment element as in the first embodiment, the degree of freedom in light distribution design is increased. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3)
In the present embodiment, as shown in FIG. 7, a reflector 23, which is a reflection optical system, is provided on the instrument body 2 as a light distribution adjusting element. The reflectors 23 are positioned in front of the front surface of the light emitting module 1 at both ends in the longitudinal direction of the fixture body 2. The reflection angle by the reflector 23 is appropriately designed according to the positional relationship with the light emitting module 1, and suppresses the spread of light emitted from the light emitting module 1.

  That is, similar to the light collecting unit 22a of the second embodiment, the reflector 23 approaches the irradiation region of the emitted light from the other light emitting modules 1 adjacent to the irradiation region of the emitted light from the light emitting module 1 at both ends. As described above (so that the amount of overlap increases), the light emitted from the light emitting modules 1 at both ends is redirected. In the present embodiment, the reflector 23 is provided to control the light distribution, so that it is possible to prevent the light amount from being gently attenuated at both ends in the longitudinal direction of the instrument body 2 and to widen the range in which the light amount is constant. .

  The shape of the reflector 23 and the position of the light emitting module 1 can be designed as appropriate. In the illustrated example, the reflecting surface of the reflector 23 is a flat surface, but may be an appropriate curved surface such as a concave surface. By using the reflector 23, there is no attenuation due to transmission through the inside of the substance, and the reflecting surface of the reflector 23 is easy to design and manufacture, so that it is easy to obtain desired characteristics. Other configurations and operations are the same as those of the first embodiment.

  By the way, in the above-described configuration example, by adjusting either the direction in which light is emitted from the light emitting module 1 or the path through which the emitted light from the light emitting module 1 is irradiated onto the printing object 20, Although the amount of light in the vicinity of both ends in the longitudinal direction of 2 is prevented from gradually decreasing, the same effect can be expected by increasing the amount of emitted light in both ends in the longitudinal direction of the instrument body 2.

  In the configuration example shown in FIG. 8, light emitting modules 1 a having a larger light output than the other light emitting modules 1 are used at both ends in the longitudinal direction of the instrument body 2. If this structure is employ | adopted, the light quantity similar to another area | region can be ensured also in the both ends of the instrument main body 2. FIG. When this configuration is adopted, the amount of light at both ends is increased as compared with the amount of light in other regions. However, since the increase in the amount of light shortens the ink curing time, there is no particular problem. This configuration can be combined with the configurations of the first, second, and third embodiments described above, and a higher effect can be expected by combining with the other configurations.

  The same effect can be obtained by changing the arrangement density by using the light emitting modules 1 of the same specification instead of the configuration in which the specifications of the light emitting modules 1a at both ends in the longitudinal direction of the instrument body 2 are different from those of the other light emitting modules 1. Can be expected. That is, as shown in FIG. 9, the arrangement density of the light emitting modules 1 at both ends in the longitudinal direction of the instrument body 2 is made higher than the arrangement density at the center. In this configuration, a light amount distribution similar to the configuration in which the light emitting module 1a having a large light output is disposed at both ends can be expected. In addition, since it is not necessary to use a light emitting module 1 of another specification, it is easy to realize.

1 is a side view showing a first embodiment. It is sectional drawing which shows the light emitting module used for the same as the above. It is operation | movement explanatory drawing which shows the example of light quantity distribution. It is a perspective view which shows the structural example of the printing apparatus using the same as the above. (A) is a side view which shows Embodiment 2, (b) is sectional drawing same as the above. It is operation | movement explanatory drawing same as the above. 10 is a side view showing Embodiment 3. FIG. It is a schematic block diagram which shows the example of arrangement | positioning of the light emitting module in the same as the above. It is a schematic block diagram which shows the example of arrangement | positioning of the light emitting module in the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting module 1a Light emitting module 2 Instrument main body 10 Package 11 Light emitting diode chip 20 Print target 21 Mounting stand 22 Projection lens 22a Condensing part 23 Reflector 30 Ultraviolet irradiation apparatus

Claims (6)

  An ultraviolet irradiation device that cures ultraviolet curable ink by irradiating ultraviolet curable ink applied to a printing object by irradiating ultraviolet rays, and a light emitting module in which a light emitting diode chip whose emission wavelength is in an ultraviolet region is incorporated in a package; An object body that holds a plurality of light emitting modules that move relative to the object to be printed and is arranged in a direction perpendicular to the direction of relative movement, and a region to be printed on the area to be irradiated with ultraviolet rays. An ultraviolet irradiation device comprising: a light distribution adjusting element for adjusting the light distribution of the light emitting modules at both ends so that the intensity of ultraviolet rays is constant over the entire length in a direction orthogonal to the direction of relative movement of the object .   The light distribution adjusting element is constituted by the appliance main body, and the appliance main body includes a mounting base for attaching the light emitting modules at both ends of the light emitting modules so that the direction of the maximum intensity is inclined toward other adjacent light emitting modules. The ultraviolet irradiation apparatus according to claim 1.   The light distribution adjusting element is a refractive optical system that is disposed in front of the light emitting modules at both ends of the light emitting module and is held by the instrument body, and the refractive optical system is a region irradiated with light emitted from the light emitting module The ultraviolet irradiation device according to claim 1, wherein the direction of light is changed so as to be close to a region irradiated with light emitted from another adjacent light emitting module.   The light distribution adjusting element is a reflective optical system disposed in front of the light emitting modules at both ends of the light emitting module and held by the instrument body, and the reflective optical system is a region irradiated with light emitted from the light emitting module The ultraviolet irradiation device according to claim 1, wherein the direction of light is changed so as to be close to a region irradiated with light emitted from another adjacent light emitting module.   5. The ultraviolet irradiation device according to claim 1, wherein light emitting modules at both ends of the light emitting module have a larger light output than other light emitting modules.   The ultraviolet light irradiation device according to any one of claims 1 to 4, wherein the light emitting module has a higher arrangement density at both ends than at a central portion.

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