JP2009292091A - Printer and ultraviolet irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer in which UVLEDs are more appropriately arranged in the printer which uses the UVLED as a light source for curing an ultraviolet-curable ink. <P>SOLUTION: The printer of an inkjet system which carries out printing using the ultraviolet-curable ink includes an inkjet head as a printing head which delivers ink droplets of the ink to a medium 50, an ultraviolet ray irradiation part 20 which illuminates the medium 50 struck with the ink droplets with ultraviolet rays, and a guide rail as a scanning driving part which scans the inkjet head and the ultraviolet ray irradiation part 20 in a preliminarily set main scanning direction. The ultraviolet ray irradiation part 20 has a first UVLED array 100a where a plurality of the UVLEDs are arranged in a sub-scanning direction orthogonal to the main scanning direction, a second UVLED array 100b where a plurality of the UVLEDs are arranged in parallel to the first UVLED array, and a condensing optical system 104 which overlaps the ultraviolet rays irradiated from the first UVLED array and the ultraviolet rays irradiated from the second UVLED array each other on the medium. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus and an ultraviolet irradiation apparatus.

  2. Description of the Related Art Conventionally, printing apparatuses using ultraviolet curable ink that is cured by irradiation with ultraviolet rays are known. In such a printing apparatus, if the time until ink cures after landing of ink droplets on the medium becomes longer, problems such as enlargement of the ink dot diameter, bleeding between dots, and ink penetration into the medium occur. There is a case. For this reason, it is preferable to shorten the time from ink landing to ink curing as much as possible.

  Here, in order to appropriately cure the ultraviolet curable ink, it is necessary to irradiate ultraviolet rays having an energy density (cumulative density) necessary for curing the ink. This energy density is a cumulative density obtained by integrating the irradiation intensity (density) of ultraviolet rays and the irradiation time. Therefore, in order to shorten the time until curing, it is necessary to increase the irradiation intensity of the ultraviolet rays irradiated to the medium.

  In order to increase the irradiation intensity of ultraviolet rays, for example, it is conceivable to increase the number of ultraviolet light sources. However, in this case, if the number of ultraviolet light sources is simply increased, the size of the apparatus will increase as the number increases. In addition, the size of the apparatus may increase the cost.

Therefore, conventionally, for example, a configuration has been proposed in which the ultraviolet light irradiation device is downsized by arranging the ultraviolet light sources so as to protrude in a direction away from the medium (see, for example, Patent Document 1). In this configuration, the ultraviolet light source is disposed, for example, on the inner surface side of a concave (for example, dome-shaped) cover member that opens toward the medium. In this configuration, as the ultraviolet light source, a light source that irradiates ultraviolet rays in the radial direction from the center is used.
JP 2004-181941 A

  In recent years, it has been studied to use UVLEDs (light emitting diodes) as ultraviolet light sources. UVLEDs have a smaller light quantity per lamp than ultraviolet light sources such as UV lamps and metal halide lamps. Therefore, for example, if the UV intensity is increased by simply increasing the number of UVLEDs, the number of necessary UVLEDs becomes very large, which may cause a significant increase in cost. Further, when the number of UVLEDs increases, it is necessary to use, for example, a water-cooled cooling device, which may further increase the cost.

  In response to this, for example, it is conceivable to reduce the number of necessary UVLEDs by efficiently using ultraviolet rays by using a three-dimensional arrangement as in Patent Document 1. However, in the UVLED, adjustment in the optical axis direction is more important than UV lamps and metal halide lamps. Therefore, for example, if a three-dimensional arrangement as in Patent Document 1 is performed, there is a risk that the burden of adjusting the optical path from the ultraviolet light source to the medium (particularly fine adjustment) may increase. For example, considering the module shape of UVLED, when performing the three-dimensional arrangement as in Patent Document 1, there is a possibility that the labor of installing the ultraviolet light source may be greatly increased.

  Therefore, when UVLED is used as an ultraviolet light source, it is required to arrange UVLED more appropriately with respect to a printing apparatus that performs printing using ultraviolet curable ink. Then, an object of this invention is to provide the printing apparatus and ultraviolet irradiation device which can solve said subject.

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) An inkjet printing apparatus that performs printing using ultraviolet curable ink that is cured by irradiation of ultraviolet rays, the print head ejecting ink droplets of ink onto a medium, and the ink droplets landed An ultraviolet irradiation unit that irradiates the medium with ultraviolet rays, and a scan drive unit that scans the print head and the ultraviolet irradiation unit in a preset main scanning direction. The ultraviolet irradiation unit is in a sub-scanning direction orthogonal to the main scanning direction. A first UVLED array in which a plurality of UVLEDs are arranged, a second UVLED array in which a plurality of UVLEDs are arranged in parallel with the first UVLED array, an ultraviolet ray emitted from the first UVLED row, and an ultraviolet ray emitted from the second UVLED row are overlapped on the medium. And a condensing optical system.

  The print head has a nozzle row in which a plurality of nozzles are arranged in the sub-scanning direction, for example. The UVLED is, for example, a UVLED module having a light-emitting diode chip that generates ultraviolet rays. Each UVLED may have a plurality of light emitting diode chips.

  The first UVLED array and the second UVLED array irradiate, for example, linear ultraviolet rays having a long side in the sub-scanning direction by a plurality of UVLEDs arranged in the sub-scanning direction. For example, the condensing optical system superimposes linear ultraviolet rays irradiated by each of the first UVLED array and the second UVLED array on the medium. Thereby, the condensing optical system overlaps a plurality of linear ultraviolet rays in a line on the medium.

  If comprised in this way, an ultraviolet-ray can be appropriately condensed on a medium, for example. For this reason, it is possible to appropriately increase the irradiation intensity of the ultraviolet rays applied to the ink on the medium. This also makes it possible to appropriately shorten the time until the ink is cured.

  Furthermore, in the case of such a configuration, the UVLED is installed on a plane parallel to the medium, for example. Therefore, the installation of the UVLED becomes easy, and the labor of installation does not increase greatly. Moreover, the adjustment work of the optical path from the UVLED to the medium is facilitated.

  Here, in order to reduce the labor of installing the UVLED, for example, it may be possible to simply install the UVLED on a plane parallel to the medium without using the above-described condensing optical system. However, in this case, in order to increase the irradiation intensity of ultraviolet rays on the medium, it is necessary to greatly increase the number of UVLEDs. As a result, the ultraviolet irradiation section is increased in size and the cost is significantly increased.

  On the other hand, since it can irradiate with an ultraviolet-ray efficiently by condensing if comprised like the structure 1, the number of required UVLED can be reduced. Therefore, for example, it is possible to appropriately reduce the size of the ultraviolet irradiation unit and reduce the cost. Accordingly, for example, a printing apparatus having a configuration suitable for using an ultraviolet curable ink can be provided.

  (Configuration 2) The ultraviolet irradiation unit further includes a heat sink for air-cooling the UVLEDs in the first UVLED array and the second UVLED array.

  For example, when UVLEDs are simply installed on a plane parallel to the medium without using the above-described condensing optical system, heat generation occurs as the number of necessary UVLEDs increases as the UV irradiation intensity is increased. The amount increases. Therefore, in this case, it may be difficult to perform sufficient cooling by the air-cooled heat sink. As a result, it is necessary to use a water-cooled cooling device or the like, which may increase the cost.

  On the other hand, since it can irradiate with an ultraviolet-ray efficiently by condensing when comprised in this way, the number of required UVLED can be reduced appropriately. Therefore, for example, the UVLED can be appropriately cooled by the heat sink without using a water-cooled cooling device or the like. Therefore, if constituted in this way, the cost of a printing apparatus can be reduced more appropriately, for example.

  (Configuration 3) The condensing optical system includes a first prism that directs an optical axis of ultraviolet rays emitted from the first UVLED row in a direction approaching the second UVLED row, and an optical axis of ultraviolet rays emitted from the second UVLED row. And a second prism directed in a direction approaching. If comprised in this way, the ultraviolet-ray from a 1st UVLED row | line and a 2nd UVLED row | line | column can be condensed appropriately, for example.

  The condensing optical system may further include, for example, a lens. This lens is, for example, a convex lens. The optical member may have a plurality of lenses respectively corresponding to the first UVLED array and the second UVLED array. In this case, the lens corresponding to the first UVLED array is provided, for example, between the first UVLED array and the first prism. In addition, the lens corresponding to the second UVLED array is provided, for example, between the second UVLED array and the second prism.

  (Configuration 4) The second UVLED array has the same number of UVLEDs as the number of UVLEDs in the first UVLED array, and each UVLED in the second UVLED array is provided with the position in the sub-scanning direction aligned with each UVLED in the first UVLED array. It is done. If comprised in this way, the ultraviolet-ray from a 1st UVLED row | line and a 2nd UVLED row | line | column can be condensed appropriately, for example.

  (Configuration 5) An ultraviolet irradiation apparatus that irradiates a medium on which ink droplets have landed with an ultraviolet irradiation apparatus in an inkjet printing apparatus that performs printing using ultraviolet curable ink that is cured by ultraviolet irradiation. A first UVLED array in which a plurality of UVLEDs are arranged in a sub-scanning direction orthogonal to the main scanning direction, which is a scanning direction, a second UVLED array in which a plurality of UVLEDs are arranged in parallel with the first UVLED array, and ultraviolet rays emitted from the first UVLED array, And a condensing optical system that overlaps the ultraviolet rays irradiated from the second UV LED array on the medium. If comprised in this way, the effect similar to the structure 1 can be acquired, for example.

  According to the present invention, for example, it is possible to provide a printing apparatus having a configuration suitable for using ultraviolet curable ink.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of a printing apparatus 10 according to an embodiment of the present invention. FIG. 1A is a top view of the printing apparatus 10. FIG. 1B is a side view of the ultraviolet irradiation unit 20 in the printing apparatus 10 and shows the ultraviolet irradiation unit 20 viewed from the downstream side in the conveyance direction of the medium 50 together with the inkjet head 12.

  The printing apparatus 10 is an ink jet printing apparatus that performs printing using ultraviolet curable ink that is cured by irradiation of ultraviolet rays. In this example, the printing apparatus 10 is a vertical inkjet printer that performs printing while conveying the medium 50, and includes a control unit 22, an inkjet head 12, a guide rail 18, a platen 14, a roller 16, and an ultraviolet irradiation unit. 20. In the modification of the present embodiment, the printing apparatus 10 may be, for example, a flat head type ink jet printer. In this case, the printing apparatus 10 appropriately includes, for example, a configuration necessary for a flat head type inkjet printer, instead of a configuration unique to a vertical type inkjet printer.

  The control unit 22 is, for example, a CPU of the printing apparatus 10 and controls the operation of each unit of the printing apparatus 10. The inkjet head 12 is a print head that ejects ink droplets onto the medium 50. In this example, the inkjet head 12 ejects ink droplets onto the medium 50 while moving in the main scanning direction (Y direction) along the guide rail 18.

  The inkjet head 12 has a nozzle row in which a plurality of nozzles are arranged in the sub-scanning direction (X direction) orthogonal to the main scanning direction, and ejects ink droplets from each nozzle of the nozzle row. The inkjet head 12 may have a plurality of nozzle rows arranged in the Y direction, for example. For example, when the printing apparatus 10 is a printing apparatus that performs color printing, the printing apparatus 10 may include a plurality of inkjet heads 12. The printing apparatus 10 may include an inkjet head 12 corresponding to, for example, four to eight colors or more.

  The guide rail 18 is a rail that guides the movement of the inkjet head 12 and the ultraviolet irradiation unit 20 in the main scanning direction. In this example, the guide rail 18 is an example of a scanning drive unit, and the inkjet head 12 and the ultraviolet irradiation unit 20 are scanned in the main scanning direction by guiding the movement of the inkjet head 12 and the ultraviolet irradiation unit 20. Let The platen 14 is a table that supports the medium 50 on which ink droplets land, and faces the inkjet head 12 with the medium 50 interposed therebetween.

  The roller 16 is a feed roller that conveys the medium 50. In this example, the roller 16 moves the inkjet head 12 relative to the medium 50 in the sub-scanning direction by conveying the medium 50 in the X direction. The printing apparatus 10 may further include other rollers. For example, the printing apparatus 10 may further include a pressing roller that sandwiches the medium 50 with the roller 16.

  The ultraviolet irradiation unit 20 irradiates the medium 50 on which the ink droplet has landed with ultraviolet rays. As a result, the ultraviolet irradiation unit 20 cures the ink ejected by the inkjet head 12. In this example, the printing apparatus 10 includes a plurality of ultraviolet irradiation units 20. The plurality of ultraviolet irradiation units 20 are provided integrally with the inkjet head 12 so as to sandwich the inkjet head 12 in the main scanning direction.

  Each ultraviolet irradiation unit 20 includes a light source that generates ultraviolet light and an optical system that condenses light from the light source. According to this example, when printing is performed while reciprocating the inkjet head 12 in the main scanning direction, it is possible to appropriately irradiate ultraviolet rays in each of the forward path and the backward path. This also makes it possible to appropriately perform a printing operation using ultraviolet curable ink.

  The position where the ultraviolet irradiation unit 20 is provided may be a position different from the above, for example. For example, the ultraviolet irradiation unit 20 may be provided on the downstream side of the inkjet head 12 in the conveyance direction of the medium 50. In this case, for example, the ultraviolet irradiation unit 20 moves in the main scanning direction independently of the inkjet head 12 along a guide rail for the ultraviolet irradiation unit 20 provided in parallel with the guide rail 18. Even when configured in this manner, the ink on the medium 50 can be appropriately irradiated with ultraviolet rays. This also makes it possible to appropriately perform a printing operation using ultraviolet curable ink.

  FIG. 2 shows a first example of the configuration of the ultraviolet irradiation unit 20. FIG. 2A shows an example of the arrangement of the UVLEDs 102 used as the ultraviolet light source in the ultraviolet irradiation unit 20. FIG. 2B shows an example of the configuration of the ultraviolet irradiation unit 20. In this example, the ultraviolet irradiation unit 20 includes a plurality of UVLED rows 100a and 100b, a condensing optical system 104, an ultraviolet reflection unit 110, and a heat sink 112.

  The plurality of UVLED arrays 100a and 100b are examples of the first UVLED array and the second UVLED array, and each include a plurality of UVLEDs 102 arranged in the X direction. With this configuration, each of the UVLED rows 100a and 100b irradiates linear ultraviolet rays having long sides in the X direction. Further, in this example, the UVLED array 100b has the same number of UVLEDs 102 as the number of UVLEDs 102 in the UVLED array 100a. The respective UVLEDs 102 in the UVLED row 100b are arranged in parallel with the UVLED row 100a with the positions in the X direction aligned with the respective UVLEDs 102 in the UVLED row 100a.

  The UVLED 102 in each of the UVLED rows 100a and 100b is, for example, a UVLED module having a light emitting diode chip 202 that generates ultraviolet rays. Each UVLED 102 may have a plurality of light emitting diode chips 202. For example, each UVLED 102 may have 3 to 5 (for example, 4) chips 202. Further, the emission center wavelength of the UVLED 102 is a wavelength in the range of 360 to 420 nm.

  Further, the UVLEDs 102 in the UVLED array 100b may be arranged with the position in the X direction shifted from the UVLEDs 102 in the UVLED array 100a. In this case, the plurality of UV LEDs 102 in the ultraviolet irradiation unit 20 are arranged in a staggered pattern vertically and horizontally. If comprised in this way, the light quantity of the ultraviolet-ray irradiated from the range where UVLED102 is arranged can be equalized, for example.

  The condensing optical system 104 is an optical system that condenses the ultraviolet rays irradiated to the medium 50 from the UVLED arrays 100a and 100b. In this example, the condensing optical system 104 includes a plurality of lenses 106a and 106b and a plurality of prisms 108a and 108b.

  The lenses 106a and 106b are convex lenses that collect ultraviolet rays irradiated from the UVLED rows 100a and 100b. In this example, the lenses 106a and 106b are columnar lenses having the X direction as the longitudinal direction (axial direction). The lens 106a is provided between the UVLED array 100a and the prism 108a, collects the ultraviolet rays emitted from the UVLED array 100a, and makes the ultraviolet light incident on the prism 108a. The lens 106b is provided between the UVLED array 100b and the prism 108b, collects the ultraviolet rays emitted from the UVLED array 100b, and makes the ultraviolet light incident on the prism 108b.

  The prism 108 a is a prism that directs the optical axis of the ultraviolet light emitted from the UVLED array 100 a in a direction approaching the UVLED array 100 b, and is provided between the lens 106 a and the medium 50. The prism 108 b is a prism that directs the optical axis of ultraviolet rays emitted from the UVLED array 100 b in a direction approaching the UVLED array 100 a, and is provided between the lens 106 b and the medium 50.

  Note that the direction of the optical axis in the direction approaching the UVLED array 100b is, for example, bending the optical axis in the direction from the UVLED array 100a to the UVLED array 100b as illustrated. Directing the optical axis in a direction approaching the UVLED array 100a means, for example, bending the optical axis in a direction from the UVLED array 100b toward the UVLED array 100a.

  With such a configuration, the condensing optical system 104 overlaps, for example, a plurality of linear ultraviolet rays irradiated by the UVLED rows 100 a and 100 b in a row on the medium 50. According to this example, for example, the ultraviolet rays from the UVLED rows 100a and 100b can be appropriately condensed.

  The ultraviolet reflecting unit 110 is a reflecting mirror that surrounds the array (array) of the UVLEDs 102. In this example, the ultraviolet reflecting unit 110 surrounds the UVLED rows 100 a and 100 b and the condensing optical system 104 with the reflecting surface facing the inside of the ultraviolet irradiating unit 20. As a result, the ultraviolet reflecting unit 110 reflects the ultraviolet rays toward the outside of the ultraviolet irradiation unit 20 toward the inside of the ultraviolet irradiation unit 20. According to this example, the ultraviolet rays irradiated from the UVLED rows 100a and 100b can be used more efficiently.

  The heat sink 112 is a heat sink that air-cools the UVLEDs 102 in the UVLED rows 100a and 100b. In this example, the heat sink 112 is provided on the back surface side of the UVLED 102 in the UVLED rows 100a and 100b.

  According to this example, for example, ultraviolet light can be appropriately condensed on the medium 50 by the condensing optical system 104. Therefore, it is possible to appropriately increase the irradiation intensity of the ultraviolet rays that are applied to the ink on the medium 50. This also makes it possible to appropriately shorten the time until the ink is cured.

  Moreover, the number of required UVLEDs 102 can be reduced appropriately by performing condensing. Therefore, according to this example, the ultraviolet irradiation unit 20 can be appropriately downsized. Further, by reducing the number of UVLEDs 102, the UVLEDs 102 can be appropriately cooled by the heat sink 112 without using, for example, a water-cooled cooling device. Therefore, according to this example, the cost of the printing apparatus 10 can be reduced more appropriately, for example. In addition, since the heating of the ultraviolet irradiation unit 20 can be appropriately suppressed by the heat sink 112, it is possible to appropriately prevent the influence of heat generation from reaching the medium 50. Therefore, for example, even when the medium 50 having low heat resistance is used, printing can be performed appropriately.

  Furthermore, in this example, each UVLED 102 is installed on a plane parallel to the medium 50. Therefore, for example, compared with the case where the UVLEDs 102 are arranged in a three-dimensional manner, the labor for installing the UVLEDs 102 can be reduced, and the production of the ultraviolet irradiation unit 20 can be facilitated. Moreover, the adjustment operation of the optical path from the UVLED 102 to the medium 50 can be appropriately reduced.

  Here, in the modification of the present invention, as the condensing optical system 104, an optical system having another configuration having a necessary condensing function can be used. For example, the arrangement of the lenses 106a and 106b and the prisms 108a and 108b can be changed as appropriate. For example, the prisms 108a and 108b may be disposed between the UVLED 102 and the lenses 106a and 106b. In addition, as the lenses 106a and 106b, for example, an elliptical columnar shape, a semicylindrical or semielliptical columnar lens obtained by dividing a cylindrical column or an elliptical column in a plane passing through an axis, a bowl-shaped lens, or the like may be used.

  Further, as the lenses 106a and 106b, lenses having a structure in which a plurality of lenses are stacked may be used. Further, instead of the plurality of lenses 106a and 106b, one lens may be used. The condensing optical system 104 may be configured only by a lens without using the prisms 108a and 108b.

  Note that when a lens having one flat surface such as a semi-cylindrical shape, a semi-elliptical column shape, or a bowl shape is used as the lens in the condensing optical system 104, the direction of the lens is the flat surface side of the UVLED 102. The curved surface is preferably directed toward the medium 50 and the platen 14 (see FIG. 1). With this configuration, for example, when designing a lens, it is possible to change the focal length by adjusting only the shape on the curved surface side of the lens while keeping the distance between the UVLED 102 and the flat surface of the lens constant. Become. In this case, since the distance between the UVLED 102 and the flat surface of the lens does not change, the focal length can be changed while the lens mounting position is fixed. This also facilitates adjustment during lens design.

  FIG. 3 shows a second example of the configuration of the ultraviolet irradiation unit 20. In this example, the condensing optical system 104 is configured by a single lens 106. The lens 106 is, for example, a semi-cylindrical lens in which the side facing the UVLED 102 is a flat surface and the side facing the medium 50 is a curved surface, with the longitudinal direction parallel to the UVLED rows 100a and 100b, 100b and the medium 50 are provided. Thereby, the lens 106 makes the ultraviolet rays irradiated from the UVLED rows 100a and 100b overlap on the medium 50, similarly to the condensing optical system 104 in FIG.

  Also in this example, it is possible to appropriately increase the irradiation intensity of the ultraviolet rays applied to the ink on the medium 50 by the condensing optical system 104. Thereby, the time until the ink is cured can be appropriately shortened. Moreover, the number of required UVLEDs 102 can be reduced appropriately by performing condensing. Thereby, for example, cooling by the heat sink 112 can be appropriately performed. Furthermore, similarly to the ultraviolet irradiation unit 20 described with reference to FIG. 2, for example, it is possible to appropriately realize downsizing, ease of manufacturing, light path adjustment work, and the like.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The present invention can be suitably used for a printing apparatus, for example.

1 is a diagram illustrating an example of a configuration of a printing apparatus 10 according to an embodiment of the present invention. FIG. 1A is a top view of the printing apparatus 10. FIG. 1B is a side view of the ultraviolet irradiation unit 20 in the printing apparatus 10. 2 is a diagram illustrating a first example of a configuration of an ultraviolet irradiation unit 20. FIG. FIG. 2A shows an example of the arrangement of the UVLEDs 102 used as the ultraviolet light source in the ultraviolet irradiation unit 20. FIG. 2B shows an example of the configuration of the ultraviolet irradiation unit 20. It is a figure which shows the 2nd example of a structure of the ultraviolet irradiation part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printing apparatus, 12 ... Inkjet head (printing head), 14 ... Platen, 16 ... Roller, 18 ... Guide rail (scanning drive part), 20 ... Ultraviolet irradiation part, 22 ... Control unit, 50 ... Medium, 100a, 100b ... UVLED array, 102 ... UVLED, 104 ... Condensing optical system, 106, 106a, 106b ... Lens, 108a, 108b ... Prism, 110 ... Ultraviolet reflector, 112 ... Heat sink, 202 ... Chip

Claims (5)

An inkjet printing apparatus that performs printing using ultraviolet curable ink that is cured by irradiation with ultraviolet rays,
A print head for ejecting ink droplets of the ink to a medium;
An ultraviolet irradiation unit that irradiates the medium on which the ink droplet has landed with ultraviolet rays;
A scanning drive unit that scans the print head and the ultraviolet irradiation unit in a preset main scanning direction;
The ultraviolet irradiation unit is
A first UVLED array in which a plurality of UVLEDs are arranged in a sub-scanning direction orthogonal to the main scanning direction;
A second UVLED array in which a plurality of UVLEDs are arranged in parallel with the first UVLED array;
A printing apparatus comprising: a condensing optical system that overlaps the ultraviolet rays emitted from the first UVLED array and the ultraviolet rays emitted from the second UVLED array on the medium. The ultraviolet irradiation unit is
The printing apparatus according to claim 1, further comprising a heat sink that air-cools the UVLEDs in the first UVLED array and the second UVLED array. The condensing optical system is
A first prism for directing an optical axis of ultraviolet rays emitted from the first UVLED array in a direction approaching the second UVLED array;
The printing apparatus according to claim 1, further comprising: a second prism that directs an optical axis of ultraviolet light emitted from the second UVLED array in a direction approaching the first UVLED array. The second UVLED array has the same number of UVLEDs as the number of UVLEDs in the first UVLED array,
4. The printing apparatus according to claim 1, wherein each UVLED in the second UVLED array is provided so as to be aligned with a position in the sub-scanning direction with each UVLED in the first UVLED array. In an inkjet printing apparatus that performs printing using ultraviolet curable ink that is cured by ultraviolet irradiation, the ultraviolet irradiation apparatus irradiates ultraviolet rays onto a medium on which the ink droplets of the ink have landed,
A first UVLED array in which a plurality of UVLEDs are arranged in a sub-scanning direction orthogonal to a main scanning direction which is a scanning direction of the print head;
A second UVLED array in which a plurality of UVLEDs are arranged in parallel with the first UVLED array;
An ultraviolet irradiation apparatus comprising: a condensing optical system that overlaps the ultraviolet rays irradiated from the first UVLED array and the ultraviolet rays irradiated from the second UVLED array on the medium.

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