inkjet printer

Abstract

To provide an inkjet printer which enables reduction of light reaching a nozzle surface.SOLUTION: A printer 10 includes an ultraviolet light radiation device 40 which is mounted on a carriage 20 so as to be located at one side as seen in a main scanning direction Y relative to an ink head 30 and may radiate light to a light curable ink discharged to a recording medium 5. The ultraviolet light radiation device 40 has: an LED element 43; a case 45 formed with a radiation port 45H which emits light radiated from the LED element 43 to the outside; a printed circuit board 48 which is housed in the case 45 and defines a light radiation chamber 46 including the radiation port 45H with the case 45 and to which the LED element 43 is attached; and a light reflection inhibition member 50 provided at one side as seen in the main scanning direction Y relative to the LED element 43.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an inkjet printer.

Background Art

[0002] Conventionally, there is known an inkjet printer including an ink head having a plurality of nozzles that discharge photocurable ink (hereinafter referred to as photocurable ink) and a nozzle surface on which the nozzles are formed, and a carriage that mounts the ink head and is movable in the main scanning direction, and performing predetermined printing on a recording medium by an inkjet method. An inkjet printer using photocurable ink includes, for example, a light irradiation device having a plurality of LED elements that irradiate light toward the photocurable ink discharged onto the recording medium, as shown in Patent Document 1. The light irradiation device is mounted on the carriage so as to be aligned with the ink head in the main scanning direction. The photocurable ink irradiated with light cures quickly on the recording medium, and thereby a desired image is printed on the recording medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to efficiently irradiate light from a plurality of LED elements toward the recording medium in the light irradiation device and to make the light amount distribution on the irradiation surface more uniform, the arrangement positions of the LED elements are set. Here, the light irradiated from the LED elements may be reflected by the recording medium and reach the nozzle surface of the ink head. Therefore, if the amount of the reflected light exceeds a predetermined amount, the photocurable ink may cure on the nozzle surface or the nozzles, and there is a risk of clogging of the nozzles.

[0005] The present invention has been made in view of the above, and its object is to provide an inkjet printer that can reduce the amount of light reaching the nozzle surface. [Means for solving the problem]

[0006] The inventors of this invention noticed that most of the light emitted from an LED element does not reach the nozzle surface of the ink head even if it is reflected off the recording medium. On the other hand, they noticed that when the light irradiation device has multiple LED elements arranged in the main scanning direction, some of the light reflected around the LED element furthest from the ink head is reflected again at a relatively shallow angle off the recording medium, and this reflected light reaches the nozzle surface. Therefore, they found that by reducing the reflected light around the LED element furthest from the ink head, the amount of light reaching the nozzle surface can be reduced.

[0007] The inkjet printer according to the present invention comprises: a mounting table on which a recording medium is placed; an ink head having a nozzle for ejecting photocurable ink onto the recording medium placed on the mounting table; a nozzle surface on which the nozzle is formed; a carriage on which the ink head is mounted and which is movable in the main scanning direction; and a light irradiation device mounted on the carriage so as to be located on one side of the ink head in the main scanning direction and capable of irradiating light onto the photocurable ink ejected onto the recording medium. The light irradiation device comprises: an LED element as a light source; a case housing the LED element and having an irradiation port that opens downward and emits light irradiated from the LED element to the outside; a printed circuit board housed in the case and together with the case partitioning a light irradiation chamber including the irradiation port, and on which the LED element is attached; and a light reflection suppression member provided on one side of the LED element in the main scanning direction.

[0008] According to the inkjet printer of the present invention, the light irradiation device has a light reflection suppression member provided on one side of the LED element in the main scanning direction. With this configuration, even if the light irradiated from the LED element is reflected by the recording medium and re-enters the light irradiation chamber of the case, the reflection of the light that reaches the light reflection suppression member is suppressed, so that the light that travels from the light irradiation device toward the recording medium at a relatively shallow angle is reduced. As a result, the amount of light that reaches the nozzle surface can be reduced. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an inkjet printer that can reduce the amount of light reaching the nozzle surface. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of a printer according to one embodiment. [Figure 2] This is a front view of a printer with the front cover open, according to one embodiment. [Figure 3] This is a plan view of a printer with the front cover and case removed according to one embodiment. [Figure 4] This is a schematic diagram showing the configuration of the side of the carriage facing the recording medium according to one embodiment. [Figure 5] This is a cross-sectional view of an ultraviolet irradiation device according to one embodiment. [Figure 6] This is a block diagram of a printer according to one embodiment. [Figure 7] This is a cross-sectional view of an ultraviolet irradiation device according to another embodiment. [Figure 8A] This is a cross-sectional view of an ultraviolet irradiation device according to another embodiment. [Figure 8B] This is a cross-sectional view of an ultraviolet irradiation device according to another embodiment. [Figure 9] This is a cross-sectional view of an ultraviolet irradiation device according to another embodiment. [Figure 10] This is a cross-sectional view of an ultraviolet irradiation device according to another embodiment. [Figure 11] This is a bottom view of an ultraviolet irradiation device according to another embodiment. [Figure 12] This is a bottom view of an ultraviolet irradiation device according to another embodiment. [Figure 13] This is a schematic diagram showing the configuration of the side of the carriage facing the recording medium according to another embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, an inkjet printer (hereinafter simply referred to as "printer") according to an embodiment of the present invention will be described with reference to the drawings. Naturally, the embodiments described herein are not intended to particularly limit the present invention. Furthermore, the same reference numerals are used for components and parts that perform the same function, and redundant explanations are omitted or simplified as appropriate.

[0012] Figure 1 is a perspective view of the printer 10 according to this embodiment. The printer 10 prints on the recording medium 5 (see Figure 2). In the following description, when the printer 10 is viewed from the front, the direction away from the printer 10 is considered the front, and the direction towards the printer 10 is considered the rear. Left, right, up, and down refer to the left, right, up, and down directions when the printer 10 is viewed from the front, respectively. Also, the symbols F, Rr, L, R, U, and D in the drawing refer to the front, rear, left, right, up, and down directions, respectively. Also, the symbol Y in the drawing indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. The symbol X indicates the sub-scanning direction. Here, the sub-scanning direction X is the front-back direction and is perpendicular to the main scanning direction Y in a plan view. The symbol Z indicates the up-down direction. The up-down direction Z is perpendicular to the main scanning direction Y in a front view. However, the directions described above are merely defined for the sake of explanation and do not in any way limit the installation configuration of the printer 10, nor do they limit the present invention in any way.

[0013] The recording medium 5 used in this embodiment may be, for example, a flat sheet such as recording paper or transfer paper, or may be a three-dimensional object such as various cases such as a mobile phone case, small electronic devices, small parts such as key holders, photo frames, and pens, daily necessities, and accessories. The material forming the recording medium 5 may be not only papers such as plain paper and inkjet printing paper, but also resins such as polyvinyl chloride (PVC), acrylic resin, polycarbonate, polystyrene, polyethylene, polyester, polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene (ABS) copolymer, metals such as aluminum and stainless steel, carbon, pottery, ceramics, glass, rubber, leather, wood, etc.

[0014] As shown in FIG. 1, the printer 10 includes a housing 12 formed in a box shape. An internal space 12S is formed in the housing 12. The housing 12 includes a case 15 and a front cover 23. An opening 28 (see FIG. 2) is formed in the front portion of the case 15. The front cover 23 is provided to be able to open and close the opening 28 of the case 15. Here, the front cover 23 is supported by the case 15 so as to be rotatable about the rear end as an axis. By rotating the front cover 23 upward, the internal space 12S of the housing 12 and the external space are communicated. The internal space 12S is a space where printing is performed on the recording medium 5 by an ink head 30 (see FIG. 2) described later. Thus, since the internal space 12S where printing is performed is surrounded and formed by the case 15 and the front cover 23, it is difficult for dust and dirt in the external space to enter the internal space 12S during printing, and it is difficult for the light irradiated from an ultraviolet irradiation device 40 (see FIG. 2) described later to leak into the external space.

[0015] As shown in FIG. 1, a window 23A is provided in the front portion and the upper portion of the front cover 23. The window 23A is formed of, for example, a transparent acrylic plate. The window 23A is processed so that light (for example, ultraviolet light) in the external space does not reach the internal space 12S. The user can visually recognize the inside of the housing 12 through the window 23A.

[0016] Next, the internal configuration of the printer 10 will be described. As shown in FIG. 2, the printer 10 includes a guide rail 18, a carriage 20, an ink head 30, an ultraviolet irradiation device 40, and a control device 70. The guide rail 18, the carriage 20, the ink head 30, and the ultraviolet irradiation device 40 are provided in the internal space 12S. The guide rail 18 is disposed within the case 15. As shown in FIG. 3, the guide rail 18 is fixed to the support wall 15A of the case 15 and extends in the main scanning direction Y. The carriage 20 is slidably provided on the guide rail 18. The carriage 20 reciprocates in the main scanning direction Y along the guide rail 18 by a carriage moving mechanism 21 (see FIG. 6). The carriage moving mechanism 21 is controlled by the control device 70. As the carriage 20 moves in the main scanning direction Y, the ink head 30 and the ultraviolet irradiation device 40 mounted on the carriage 20 move in the main scanning direction Y.

[0017] As shown in FIG. 2, a plurality of ink heads 30 are mounted on the carriage 20. The ink heads 30 are disposed above a table 35 described later. The ink heads 30 discharge an ink having photocurability (photocurable ink) onto a recording medium 5 placed on the table 35. Each of the ink heads 30 communicates with an ink cartridge 60 accommodated in the case 15 by a flexible ink tube (not shown). The ink cartridge 60 stores the photocurable ink respectively.

[0018] As shown in Figure 4, the ink head 30 is mounted on the carriage 20. The ink heads 30 are positioned in a aligned position with respect to the sub-scanning direction X. The ink heads 30 may be positioned in a staggered position with respect to the sub-scanning direction X. That is, the ink heads 30 may be arranged in a so-called staggered configuration. The ink head 30 is formed in a shape where the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. The ink head 30 comprises a plurality of left nozzles 31A aligned in the sub-scanning direction X, a plurality of right nozzles 31B aligned in the sub-scanning direction X and located to the right of the left nozzles 31A, and a nozzle surface 31C on which the left nozzles 31A and right nozzles 31B are formed. The plurality of left nozzles 31A are arranged in a row to form a left nozzle row 33A. The plurality of right nozzles 31B are arranged in a row to form a right nozzle row 33B. The left nozzles 31A and right nozzles 31B eject photocurable ink. In Figure 4, 12 nozzles are shown on the ink head 30, but in reality, many more (e.g., 180) nozzles are formed. However, the number of nozzles is not limited in any way. Also, the number of ink heads 30 is not limited to three. Furthermore, the ink head 30 has two nozzle rows, but there may be one or more nozzle rows.

[0019] Photocurable inks are inks that harden when exposed to light (e.g., ultraviolet light). Examples of photocurable inks include inks used for image formation (i.e., image quality forming inks) and inks used for forming a base layer before image formation or for surface finishing after image formation (i.e., image quality improvement inks). Image formation inks are, for example, process color inks. Examples of process color inks include cyan ink, magenta ink, yellow ink, black ink, light cyan ink, and light magenta ink. Inks used for forming a base layer before image formation are, for example, primer inks and white inks. Primer inks are tacky. Inks used for surface finishing after image formation are, for example, gloss inks.

[0020] As shown in Figure 2, the printer 10 is equipped with one ultraviolet irradiation device 40. The ultraviolet irradiation device 40 is an example of a light irradiation device. The ultraviolet irradiation device 40 irradiates light (typically ultraviolet light). The ultraviolet irradiation device 40 is configured to irradiate light (in this case, ultraviolet light) onto the area of ​​the recording medium 5 where the photocurable ink has been ejected (i.e., the printing area). The ultraviolet irradiation device 40 is configured to irradiate light toward the photocurable ink ejected onto the recording medium 5. The ultraviolet irradiation device 40 is mounted on the carriage 20. The ultraviolet irradiation device 40 is positioned above the table 35, which will be described later. As shown in Figure 4, the ultraviolet irradiation device 40 is positioned to the right of the ink head 30. The ultraviolet irradiation device 40 may also be positioned to the left of the ink head 30.

[0021] As shown in Figure 5, the ultraviolet irradiation device 40 comprises a plurality of LED elements 43, a case 45 housing the plurality of LED elements 43, a printed circuit board 48, a light reflection suppression member 50, a heat sink 55, and glass 57.

[0022] As shown in Figure 5, the case 45 is formed in a rectangular parallelepiped shape. The case 45 includes an upper wall 45A, a front wall 45B (see Figure 4) extending downward from the front end of the upper wall 45A, a rear wall 45C (see Figure 4) extending downward from the rear end of the upper wall 45A, a left wall 45D extending downward from the left end of the upper wall 45A and connecting the front wall 45B and the rear wall 45C, and a right wall 45E extending downward from the right end of the upper wall 45A and connecting the front wall 45B and the rear wall 45C. An illumination port 45H is formed in the case 45. The illumination port 45H is formed from the front wall 45B, the rear wall 45C, the left wall 45D, and the right wall 45E. The illumination port 45H opens downward. The illumination port 45H emits light emitted from the LED element 43 to the outside. The case 45 is formed from a metallic material (e.g., iron or aluminum). Therefore, the inner surface 45M of the case 45 reflects the light emitted from the LED element 43. As shown in Figure 4, the case 45 is formed in a shape where the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. The case 45 is mounted on the carriage 20 via a connecting member 22.

[0023] As shown in Figure 4, the ultraviolet irradiation device 40 has a plurality of LED elements 43 arranged in at least the main scanning direction Y. In this embodiment, the plurality of LED elements 43 are arranged in the main scanning direction Y and the sub-scanning direction X. The LED elements 43 irradiate the photocurable ink ejected onto the recording medium 5 with light (in this case, ultraviolet light). The LED elements 43 are located in a light irradiation chamber 46 (see Figure 5), which will be described later, of the case 45. The ultraviolet irradiation device 40 has a left light source row 44A, a central light source row 44B, and a right light source row 44C. The left light source row 44A, the central light source row 44B, and the right light source row 44C are arranged in the main scanning direction Y. The left light source row 44A is located to the left of the central light source row 44B. The right light source row 44C is located to the right of the central light source row 44B. The left light source row 44A, the central light source row 44B, and the right light source row 44C are each composed of a plurality of LED elements 43 arranged in a single row in the sub-scanning direction X. Hereinafter, the left light source row 44A, the central light source row 44B, and the right light source row 44C will be collectively referred to as the light source row 44. The light source row 44 is located to the side (in this case, to the right) of the ink head 30. The length of the sub-scanning direction X of the light source row 44 is longer than the length of the sub-scanning direction X of the left nozzle row 33A and the right nozzle row 33B of the ink head 30. Although 18 LED elements 43 are shown in each row in Figure 4, in reality, many more (for example, 30) light sources are provided.

[0024] As shown in Figure 5, the printed circuit board 48 is housed in a case 45. The printed circuit board 48 is held in the case 45. Multiple LED elements 43 are mounted on the printed circuit board 48. Together with the case 45, the printed circuit board 48 partitions a light irradiation chamber 46 and a component placement chamber 47. The light irradiation chamber 46 includes an irradiation port 45H. The component placement chamber 47 is located above the light irradiation chamber 46. On the lower surface 48A of the printed circuit board 48, which faces the light irradiation chamber 46, a light-reflecting member is provided to promote light reflection. The light-reflecting member is, for example, a white coating of light-reflecting paint (e.g., white silicone ink from Asahi Rubber Co., Ltd. or white solder resist from Sekisui Chemical Co., Ltd.).

[0025] As shown in Figure 5, the light reflection suppression member 50 is located in the light irradiation chamber 46. The light reflection suppression member 50 is a member that suppresses (prevents) the reflection of light. The light reflection suppression member 50 is, for example, a black coating of light reflection suppression paint (for example, fluororesin paint). The light reflection suppression member 50 absorbs reflected light, for example. The light reflection suppression member 50 is provided around the outermost LED element 43M, which is located furthest to the right among the multiple LED elements 43. That is, the light reflection suppression member 50 is provided around the right light source row 44C (see Figure 4). Here, the outermost LED element 43M is the LED element 43 that is furthest from the ink head 30 with respect to the main scanning direction Y. In this embodiment, the light reflection suppression member 50 is provided to the right of the right end of the outermost LED element 43M. The light reflection suppression member 50 is provided from the right end of the outermost LED element 43M to the inner surface 45M of the right wall 45E of the case 45. As shown in Figure 4, the light reflection suppression member 50 is provided extending from the inner surface 45M of the front wall 45B of the case 45 to the inner surface 45M of the rear wall 45C of the case 45. The light reflection suppression member 50 is provided on the lower surface 48A of the printed circuit board 48. As indicated by arrow P in Figure 5, light reflected from the portion of the printed circuit board 48 where the light reflection suppression member 50 is provided may be emitted to the outside from the irradiation port 45H at a relatively shallow angle, then reflected again by the recording medium 5 and reach the nozzle surface 31C of the ink head 30. However, in this embodiment, since the light reflection suppression member 50 is provided on a specific portion of the printed circuit board 48, the reflection of light is suppressed at the light reflection suppression member 50, and the light indicated by arrow P as described above is prevented from reaching the nozzle surface 31C. In this embodiment, since the ultraviolet irradiation device 40 is located to the right of the ink head 30, the LED element 43 located furthest to the right among the multiple LED elements 43 corresponds to the outermost LED element 43M. However, if the ultraviolet irradiation device 40 is located to the left of the ink head 30, the LED element 43 located furthest to the left among the multiple LED elements 43 corresponds to the outermost LED element 43M. That is, in a single ultraviolet irradiation device 40, the LED element 43 located furthest from the ink head 30 with respect to the main scanning direction Y becomes the outermost LED element 43M.

[0026] As shown in Figure 5, the heat sink 55 is placed in the component placement chamber 47. The heat sink 55 is in contact with the printed circuit board 48. The heat sink 55 is placed on top of the printed circuit board 48. The heat sink 55 is a component used for the purpose of dissipating heat from the printed circuit board 48.

[0027] As shown in Figure 5, the glass 57 is placed in the light irradiation chamber 46. The glass 57 is held in the case 45. The glass 57 is positioned to cover the irradiation port 45H. The glass 57 is transparent.

[0028] As shown in Figure 2, the printer 10 is a so-called flatbed type printer. The printer 10 includes a table 35 located below the carriage 20, a first table movement mechanism 36, and a second table movement mechanism 37. The table 35, the first table movement mechanism 36, and the second table movement mechanism 37 are located in the internal space 12S. The table 35 is an example of a mounting platform. A recording medium 5 is placed on the table 35. The table 35 is a platform that supports the recording medium 5. The table 35 is configured to be movable in the sub-scanning direction X by the first table movement mechanism 36. The table 35 is configured to be movable in the vertical direction Z by the second table movement mechanism 37.

[0029] As shown in Figure 2, the first table moving mechanism 36 comprises slide rails 36a and 36b, a transport member 36c, a ball screw 36d, and a first motor 39A (see also Figure 6). The slide rails 36a and 36b extend in the sub-scanning direction X. The transport member 36c is slidably mounted relative to the slide rails 36a and 36b. Above the transport member 36c, the table 35 is supported via other members. The transport member 36c is connected to the ball screw 36d. The ball screw 36d extends in the sub-scanning direction X. The first motor 39A is connected to the ball screw 36d via a gear (not shown). The first motor 39A rotates the ball screw 36d. The first motor 39A is electrically connected to and controlled by the control device 70. When the first motor 39A is driven, the transport member 39c moves in the sub-scanning direction X along the slide rails 36a and 36b due to the rotation of the ball screw 36d. As a result, the table 35 moves in the sub-scanning direction X.

[0030] As shown in Figure 2, the second table movement mechanism 37 comprises a height adjustment member 37a and a second motor 39B (see Figure 6). The height adjustment member 37a is located on the underside of the table 35. The height adjustment member 37a is connected to the second motor 39B. The second motor 39B is electrically connected to the control device 70 and controlled by the control device 70. When the second motor 39B is driven, the height of the height adjustment member 37a changes, and the height of the table 35 is adjusted. That is, the table 35 moves in the vertical direction Z.

[0031] As shown in Figure 6, the control device 70 is a device that controls printing to the recording medium 5. The configuration of the control device 70 is not particularly limited. The control device 70 is, for example, a microcomputer. The control device 70 is communicatively connected to and controls the carriage movement mechanism 21, the ink head 30, the ultraviolet irradiation device 40, the first motor 39A of the first table movement mechanism 36 (see Figure 2), and the second motor 39B of the second table movement mechanism 37 (see Figure 2).

[0032] As shown in Figure 6, the control device 70 comprises a print control unit 71, a light source control unit 72, and a movement control unit 73. The functions of each part of the control device 70 are realized by a program. The print control unit 71 is the part that forms an image on the recording medium 5. The print control unit 71 controls the carriage movement mechanism 21 and the ink head 30. The light source control unit 72 controls the LED element 43 of the ultraviolet irradiation device 40. The light source control unit 72 is the part that irradiates light from the LED element 43 onto the photocurable ink ejected onto the recording medium 5 to cure the photocurable ink. The movement control unit 73 is the part that moves the recording medium 5 in the sub-scanning direction X. The movement control unit 73 controls the first motor 39A.

[0033] As described above, according to the printer 10 of this embodiment, the ultraviolet irradiation device 40 has a light reflection suppression member 50 provided around the outermost LED element 43M (i.e., the LED element 43 furthest from the ink head 30 with respect to the main scanning direction Y) located on the furthest side (here, the right side) of the plurality of LED elements 43 arranged in the main scanning direction Y. With this configuration, even if the light irradiated from the LED element 43 is reflected by the recording medium 5 and re-enters the light irradiation chamber 46 of the case 45, the reflection of the light that reaches the light reflection suppression member 50 is suppressed, so that the light that travels from the ultraviolet irradiation device 40 toward the recording medium 5 at a relatively shallow angle is reduced. This makes it possible to reduce the amount of light that reaches the nozzle surface 31C.

[0034] In the printer 10 of this embodiment, the light reflection suppression member 50 is provided at least to the right of one end (here, the right end) in the main scanning direction Y of the outermost LED element 43M. The further to the right the position is from the right end of the main scanning direction of the outermost LED element 43M, the more the reflected light tends to be directed toward the recording medium 5 at a relatively shallow angle. By providing the light reflection suppression member 50 at such a position, the amount of light reaching the nozzle surface 31C can be reduced.

[0035] In the printer 10 of this embodiment, the light reflection suppression member 50 is provided extending from at least one end of the outermost LED element 43M in the main scanning direction Y (in this case, the right end) to one inner surface of the case 45 in the main scanning direction Y (in this case, the inner surface 45M of the right wall 45E). This makes it possible to further reduce the amount of light reaching the nozzle surface 31C.

[0036] In the printer 10 of this embodiment, the light reflection suppression member 50 is a coating of light reflection suppression paint applied to the lower surface 48A of the printed circuit board 48. As a result, the light reflection suppression member 50 can absorb light, further reducing the amount of light that reaches the nozzle surface 31C.

[0037] In the printer 10 of this embodiment, the printed circuit board 48 is divided together with the case 45 into a light irradiation chamber 46 and a component placement chamber 47 located above the light irradiation chamber 46, and the ultraviolet irradiation device 40 is equipped with a heat sink 55 placed in the component placement chamber 47 so as to be in contact with the printed circuit board 48. This makes it possible to further suppress the rise in temperature of the printed circuit board 48.

[0038] Preferred embodiments of the present invention have been described above. However, the embodiments described above are merely illustrative, and the present invention can be implemented in various other forms.

[0039] Figure 7 is a cross-sectional view of the ultraviolet irradiation device 240 according to the second embodiment. As shown in Figure 7, in the ultraviolet irradiation device 240, a gap is provided between the printed circuit board 48 and the inner surface 45M of the right wall 45E of the case 45. That is, the printed circuit board 48 is not in contact with the inner surface 45M of the right wall 45E of the case 45 with respect to the main scanning direction Y. In this embodiment, the light reflection suppression member 50 is provided extending from the right end of the printed circuit board 48 to the inner surface 45M of the right wall 45E of the case 45. The light reflection suppression member 50 is provided, for example, on the lower surface 55A of the heat sink 55. The light reflection suppression member 50 may be arranged at a distance from the heat sink 55.

[0040] FIG. 8A is a cross-sectional view of the ultraviolet irradiation device 340 according to the third embodiment. As shown in FIG. 8A, in the ultraviolet irradiation device 340, the light reflection suppression member 350 extends downward from the lower surface 48A of the printed circuit board 48. In the present embodiment, the light reflection suppression member 350 is provided to the right of the outermost LED element 43M. The light reflection suppression member 350 is formed of, for example, a metal material. The light reflection suppression member 350 is formed in a plate shape. A black coating film of a light reflection suppression paint may be formed on the surface of the light reflection suppression member 350. When the length in the vertical direction Z of the light reflection suppression member 350 is defined as length L1 and the length in the vertical direction Z of the light irradiation chamber 46 is defined as length L2, the relationship of L1≈0.1×L2 to L1≈1×L2 is satisfied. As shown in FIG. 8B, this relationship is obtained from the relationship between L1 and L2 so that the light of arrow P reflected at the end on the opposite side of the ink head 30 of the ultraviolet irradiation device 340 (for example, the right end 48AR of the lower surface 48A of the printed circuit board 48) does not enter the nozzle surface 31C of the ink head 30. That is, as shown in FIG. 8B, since it is necessary to block the light by the light reflection suppression member 350 so that the light emitted from the right end 48AR (reflected by the inner surface 45M) does not enter the nozzle surface 31C of the ink head 30, when the length in the main scanning direction Y from the ink head 30 to the ultraviolet irradiation device 340 is a, the length in the main scanning direction Y of the ultraviolet irradiation device 340 is b, the length in the vertical direction Z from the lower end portion of the ultraviolet irradiation device 340 (that is, the lower surface of the glass 57) to the recording medium 5 is e, and the length in the main scanning direction Y from the light reflection suppression member 350 to the inner surface 45M of the right wall 45E is g, it is set to (L2 + 2e)g / (a + b)≤L1<L2. For example, when a = 30 (mm), b = 40 (mm), e = 2 (mm), g = 5 (mm), and L2 = 10 (mm), L1 is set to 1 (mm) to 10 (mm). According to the ultraviolet irradiation device 340 of the present embodiment, the angle of the light traveling toward the recording medium 5 can be restricted, and the reflected light traveling toward the recording medium 5 at a relatively shallow angle can be reduced.

[0041] Figure 9 is a cross-sectional view of the ultraviolet irradiation device 440 according to the fourth embodiment. As shown in Figure 9, the light reflection suppression member 450 extends downward from the lower surface 48A of the printed circuit board 48. In this embodiment, the light reflection suppression member 450 is provided to the right of the outermost LED element 43M. The light reflection suppression member 450 has an inclined surface 450M whose length in the vertical direction Z decreases as it moves from the right end of the outermost LED element 43M to the inner surface 45M of the right wall 45E of the case 45. The light reflection suppression member 450 is formed from, for example, a metal material. Preferably, a black coating of light reflection suppression paint is formed on the surface of the light reflection suppression member 450. According to the ultraviolet irradiation device 440 of this embodiment, the angle of light directed toward the recording medium 5 can be limited, and reflected light directed toward the recording medium 5 at a relatively shallow angle can be reduced.

[0042] As shown in Figure 9, in the ultraviolet irradiation device 440, light reflection suppression members 50 are provided on the inner surfaces 45M of the right wall 45E and the left wall 45D of the case 45, which partition the light irradiation chamber 46. The light reflection suppression members 50 are, for example, a coating of light reflection suppression paint. The light reflection suppression members 50 are provided in the upper region R1 when the portion of the case 45 that partitions the light irradiation chamber 46 is divided into an upper region R1 and a lower region R2 from top to bottom. The light reflection suppression members 50 are preferably in contact with the printed circuit board 48 or the light reflection suppression members 450. With this configuration, the angle of light directed toward the recording medium 5 can be further restricted, and reflected light directed toward the recording medium 5 at a relatively shallow angle can be further reduced. It is preferable that the light reflection suppression members 50 are provided on at least the inner surface 45M of the right wall 45E. Furthermore, the light reflection suppression member 50 may be provided on all of the inner surfaces 45M of the right wall 45E and the left wall 45D of the light irradiation chamber 46.

[0043] Figure 10 is a cross-sectional view of the ultraviolet irradiation device 540 according to the fifth embodiment. As shown in Figure 10, in the ultraviolet irradiation device 540, the case 45 has a glass holder 558 that holds the glass 57. The glass holder 558 has a shielding member 559 that extends from the inner surface 45M of the right wall 45E of the case 45 toward the right end of the outermost LED element 43M, and a shielding member 560 that extends to the right from the inner surface 45M of the left wall 45D of the case 45. The shielding members 559 and 560 are located below the printed circuit board 48. A light reflection suppression member 50 is provided on the lower surface 559A of the shielding member 559. The light reflection suppression member 50 is, for example, a black coating of light reflection suppression paint. According to the ultraviolet irradiation device 540 of this embodiment, the light reflection suppression member 50 can absorb light, and the amount of light reaching the nozzle surface 31 can be further reduced. Furthermore, since the shielding members 559 and 560 reduce the amount of light reaching the printed circuit board 48, the temperature rise of the printed circuit board 48 can be suppressed. In addition, by providing the light reflection suppression member 50 on the shielding members 559 and 560 of the glass holder 558 that holds the glass 57, the amount of light reaching the nozzle surface 31 can be easily reduced.

[0044] Figure 11 is a cross-sectional view of the ultraviolet irradiation device 640 according to the sixth embodiment. As shown in Figure 11, in the ultraviolet irradiation device 640, the light reflection suppression member 50 does not overlap with the outermost LED element 43M when viewed from below, and is provided extending from the left end of the outermost LED element 43M to the inner surface 45M of the right wall 45E of the case 45. This makes it possible to further reduce the amount of light reaching the nozzle surface 31.

[0045] Figure 12 is a cross-sectional view of the ultraviolet irradiation device 740 according to the seventh embodiment. As shown in Figure 12, in the ultraviolet irradiation device 740, the left light source row 44A, the central light source row 44B, and the right light source row 44C are each composed of multiple LED elements 43 arranged in a zigzag pattern in the sub-scanning direction X. In this embodiment, from front to back, the odd-numbered LED elements 43 are biased to the left and the even-numbered LED elements 43 are biased to the right. Note that the odd-numbered LED elements 43 and the even-numbered LED elements 43 partially overlap with respect to the main scanning direction Y. The light reflection suppression member 50 does not overlap with the outermost LED elements 43M when viewed from the bottom, and is provided from the right end of the odd-numbered outermost LED elements 43M to the inner surface 45M of the right wall 45E of the case 45. This makes it possible to further reduce the amount of light reaching the nozzle surface 31.

[0046] In the embodiment described above, the printer 10 was equipped with one ultraviolet irradiation device 40, but it may also be equipped with ultraviolet irradiation devices 40 to the right and left of the ink head 30. In such a configuration, as shown in Figure 13, in the left ultraviolet irradiation device 40, the LED element 43 of the left light source row 44A corresponds to the outermost LED element 43M. The light reflection suppression member 50 is provided to the left of the left end of the outermost LED element 43M. The light reflection suppression member 50 is provided extending from the left end of the outermost LED element 43M to the inner surface 45M of the left wall 45D of the case 45.

[0047] In the embodiment described above, the ultraviolet irradiation device 40 had a plurality of LED elements 43 arranged in the main scanning direction Y (i.e., three light source rows: a left light source row 44A, a central light source row 44B, and a right light source row 44C). However, the number of LED elements 43 with respect to the main scanning direction Y may be 1, 2, or 4 or more (i.e., the number of light source rows may be 1, 2, or 4 or more). The light reflection suppression members 50, 350, and 450 are provided for the LED element 43 that is furthest from the ink head 30 with respect to the main scanning direction Y (for example, the outermost LED element 43M).

[0048] In the embodiment described above, the printer 10 was equipped with a first table moving mechanism 36 as a moving device that moves the recording medium 5 relative to the carriage 20 in the sub-scanning direction X by moving the table 35 on which the recording medium 5 is placed relative to the carriage 20 in the sub-scanning direction X, but is not limited to this. For example, the printer may be equipped with a moving device that fixes the table 35 to the housing 12 and moves the carriage 20 relative to the table 35 in the sub-scanning direction X, thereby moving the recording medium 5 relative to the carriage 20 in the sub-scanning direction X.

[0049] The technology disclosed herein can be applied to various types of printers. In addition to the flatbed type printer 10 shown in the embodiments described above, it can also be similarly applied to a so-called roll-to-roll type printer 10 that transports a roll-shaped recording medium 5 in the sub-scanning direction X. [Explanation of Symbols]

[0050] 5. Recording media 10. Printer (inkjet printer) 20 Carriage 30 Inkheads 31C Nozzle surface 35 Table (Platform) 40 Ultraviolet irradiation device (light irradiation device) 43 LED elements 43M outermost LED element 45 cases 45E Right wall 45H irradiation port 45M inner 46 Light irradiation room 48 Printed circuit boards 48A Bottom 50 Light reflection suppression member 55 Heatsink 57 Glass

Claims

1. A mounting platform on which the recording medium is placed, An ink head having a nozzle for ejecting photocurable ink onto the recording medium placed on the mounting base, and a nozzle surface on which the nozzle is formed, A carriage equipped with the aforementioned ink head and movable in the main scanning direction, The carriage is mounted such that it is located on one side of the main scanning direction from the ink head, and includes a light irradiation device capable of irradiating light toward the photocurable ink ejected onto the recording medium, The aforementioned light irradiation device is LED elements as light sources, A printed circuit board on which the aforementioned LED element is attached, A case that houses the printed circuit board and has an illumination port that opens downward and emits light from the LED element to the outside, An inkjet printer having a light reflection suppression member provided on the lower surface of the printed circuit board on one side of the main scanning direction from the LED element.

2. The inkjet printer according to claim 1, wherein the light reflection suppression member is provided on the lower surface of the printed circuit board on one side of the main scanning direction, beyond the end of the LED element on one side of the main scanning direction.

3. The printed circuit board is held in contact with the inner surface of the case, The inkjet printer according to claim 2, wherein the light reflection suppression member is provided on the lower surface of the printed circuit board, extending from one end of the LED element in the main scanning direction to the inner surface of the case on one side in the main scanning direction.

4. The inkjet printer according to claim 3, wherein the light reflection suppression member does not overlap with the LED element when viewed from below, and is provided on the lower surface of the printed circuit board extending from the other end of the LED element in the main scanning direction to the inner surface of the case on one side in the main scanning direction.

5. The LED elements are arranged in a plurality in the main scanning direction, The light reflection suppression member is provided for the outermost LED element located on the one side of the main scanning direction among the plurality of LED elements, according to any one of claims 1 to 4.

6. The inkjet printer according to any one of claims 1 to 5, wherein the light reflection suppressing member is a coating of light reflection suppressing paint provided on the lower surface of the printed circuit board.

7. The inkjet printer according to claim 1 or 2, wherein the light reflection suppressing member extends downward from the lower surface of the printed circuit board.

8. The inkjet printer according to claim 1, wherein the light reflection suppression member has an inclined surface whose vertical length decreases as it moves from one end of the LED element in the main scanning direction toward the inner surface of the case on the same side in the main scanning direction.

9. A mounting platform on which a recording medium is placed, An ink head having a nozzle for ejecting photocurable ink onto the recording medium placed on the mounting base, and a nozzle surface on which the nozzle is formed, A carriage equipped with the aforementioned ink head and movable in the main scanning direction, The carriage is mounted such that it is located on one side of the main scanning direction from the ink head, and includes a light irradiation device capable of irradiating light toward the photocurable ink ejected onto the recording medium, The aforementioned light irradiation device is LED elements as light sources, A printed circuit board on which the aforementioned LED element is attached, A case that houses the printed circuit board and has an illumination port that opens downward and emits light from the LED element to the outside, The system comprises a light reflection suppression member provided on one side of the LED element in the main scanning direction, The case is located below the printed circuit board and has a shielding member extending from the inner surface of the case on one side in the main scanning direction toward the end of the LED element on one side in the main scanning direction. The light reflection suppressing member is a coating of light reflection suppressing paint provided on the lower surface of the shielding member, in an inkjet printer.

10. The light irradiation device includes a glass that covers the irradiation port, The inkjet printer according to claim 9, wherein the case has a glass holder that holds the glass and includes the shielding member.

11. A mounting platform on which a recording medium is placed, An ink head having a nozzle for ejecting photocurable ink onto the recording medium placed on the mounting base, and a nozzle surface on which the nozzle is formed, A carriage equipped with the aforementioned ink head and movable in the main scanning direction, The carriage is mounted such that it is located on one side of the main scanning direction from the ink head, and includes a light irradiation device capable of irradiating light toward the photocurable ink ejected onto the recording medium, The aforementioned light irradiation device is LED elements as light sources, A printed circuit board on which the aforementioned LED element is attached, A case that houses the printed circuit board and has an illumination port that opens downward and emits light from the LED element to the outside, An inkjet printer having a light reflection suppression member provided extending from one end of the printed circuit board in the main scanning direction to the inner surface of the case in the main scanning direction.

12. A mounting platform on which a recording medium is placed, An ink head having a nozzle for ejecting photocurable ink onto the recording medium placed on the mounting base, and a nozzle surface on which the nozzle is formed, A carriage equipped with the aforementioned ink head and movable in the main scanning direction, The carriage is mounted such that it is located on one side of the main scanning direction from the ink head, and includes a light irradiation device capable of irradiating light toward the photocurable ink ejected onto the recording medium, The aforementioned light irradiation device is LED elements as light sources, A printed circuit board on which the aforementioned LED element is attached, A case that houses the printed circuit board and has an illumination port that opens downward and emits light from the LED element to the outside, The system comprises a light reflection suppression member provided on the inner surface of the case on one side of the main scanning direction from the LED element, The light reflection suppressing member is a coating film of light reflection suppressing paint, An inkjet printer in which, when the region of the case below the printed circuit board is divided into an upper region and a lower region from top to bottom, the coating film of the light reflection suppressing paint is provided in the upper region.

13. The inkjet printer according to any one of claims 1 to 12, wherein the light irradiation device comprises a heat sink arranged to be in contact with the printed circuit board.

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