Inkjet printer

Abstract

To provide an inkjet printer in which light emitted from a light irradiation device is less likely to be reflected to an ink head.SOLUTION: An inkjet printer includes: a table 35 on which a recording medium 5 is placed; and a carriage 20 disposed above the table 35, where an ink head 30 is mounted to the carriage 20. A light irradiation device 40 is disposed on a lateral side of the ink head 30 and is mounted to the carriage 20 via a connection member 22. A top face of the table 35 is constituted of a retroreflective material 50.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Inkjet printers have been known for some time that use ink that hardens when exposed to light (hereinafter referred to as photocurable ink) to perform a desired print on a recording medium. Such inkjet printers include nozzles, an ink head, a carriage, and a table. A recording medium is placed on the table. The photocurable ink is ejected from the nozzles toward the recording medium. Multiple nozzles are provided on the underside of the ink head. The ink head is mounted on a carriage located above the table. The carriage is movable in the main scanning direction.

[0003] Furthermore, the inkjet printer is equipped with a light irradiation device that irradiates light to cure the photocurable ink. For example, the light irradiation device is a device equipped with LED elements as shown in Patent Document 1. The light irradiation device is mounted on a carriage. The light irradiation device is located to the side of the ink head. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-88125 Summary of the Invention [Problem to be solved by the invention]

[0005] In inkjet printers that use photocurable ink, one of the causes of ink head failure is thought to be thickening of the photocurable ink adhering to the ink head surface. This thickening occurs when light emitted from a light irradiation device is reflected by a table or other object and reaches the ink head. When wiping the ink head to clean it, the thickened photocurable ink adhering to the ink head surface may get mixed into the nozzles. This can result in nozzle clogging and ink head failure.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an inkjet printer in which light emitted from a light emitting device is less likely to be reflected back to the ink head. [Means for solving the problem]

[0007] The inkjet printer of the present invention comprises a box-shaped housing, a table located inside the housing on which a recording medium is placed, a carriage located inside the housing and above the table and movable in the main scanning direction, an ink head mounted on the carriage, a plurality of nozzles formed on the underside of the ink head for ejecting photocurable ink toward the recording medium, a light irradiation device mounted on the carriage so as to be positioned to the side of the ink head and for irradiating light toward the photocurable ink ejected onto the recording medium, and a retroreflective material provided in at least a part of the irradiation range of the light irradiation device inside the housing.

[0008] A retroreflective material is a material that reflects incident light back in the direction of incidence. According to the inkjet printer described above, the retroreflective material is provided in at least a portion of the irradiation range of the light irradiation device inside the housing. Therefore, of the light irradiated from the light irradiation device, light that reaches the retroreflective material is reflected back to the light irradiation device. As a result, compared to inkjet printers that do not have a retroreflective material, the light irradiated from the light irradiation device is less likely to be reflected back to the ink head. The photocurable ink attached to the surface of the ink head is less likely to thicken. This can reduce ink head failure. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an inkjet printer in which light emitted from a light irradiation device is less likely to be reflected back to an ink head. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a printer according to an embodiment. [Figure 2] FIG. 2 is a front view of the printer with the front cover open. [Figure 3] FIG. 2 is a plan view of the printer with the front cover and case removed. [Figure 4] FIG. 2 is a schematic diagram of the carriage as viewed from below. [Figure 5] FIG. 10 is a front view of a carriage and a table in a printer in which the top surface of the table is made of a retroreflective material. [Figure 6] FIG. 1 is a schematic diagram of a retroreflective material. [Figure 7] FIG. 1 is a block diagram of a printer. [Figure 8] FIG. 10 is a front view of the carriage and the table when the jig is provided to the side of the recording medium. [Figure 9] FIG. 10 is a front view of a carriage and a table in a printer in which only the edge of the top surface of the table in the main scanning direction is made of retroreflective material. DETAILED DESCRIPTION OF THE INVENTION

[0011] An inkjet printer (hereinafter simply referred to as a printer) according to one embodiment of the present invention will be described below with reference to the drawings. It should be noted that the embodiment described here is not intended to particularly limit the present invention. Furthermore, members and parts that perform the same function are given the same reference numerals, and duplicate descriptions will be omitted or simplified as appropriate.

[0012] FIG. 1 is a perspective view of a printer 10 according to this embodiment. The printer 10 according to this embodiment is a flatbed printer. For convenience, the directions of the printer 10 are defined as follows: When viewed from the front, the direction away from the printer 10 is referred to as the front, and the direction toward the printer 10 is referred to as the rear. When viewed from the front, the left, right, top, and bottom directions are simply referred to as left, right, top, and bottom. The symbols F, Rr, L, R, U, and D in the drawings represent the front, back, left, right, top, and bottom, respectively. The symbol Y in the drawings indicates the main scanning direction. The symbol X in the drawings indicates the sub-scanning direction. Here, the main scanning direction Y is the left-right direction, and the sub-scanning direction X is the front-to-back direction. The main scanning direction Y and the sub-scanning direction X are perpendicular to each other. The symbol Z in the drawings indicates the up-down direction. The up-down direction Z is perpendicular to the main scanning direction Y and the sub-scanning direction X. The directions defined here are merely for convenience and do not limit the installation mode of the printer 10 or the present invention.

[0013] As shown in FIG. 1, the printer 10 includes a box-shaped housing 12. The housing 12 includes a case 15 and a front cover 23. An internal space 12S is formed inside the housing 12. The printer 10 prints on a recording medium 5 in the internal space 12S. As shown in FIG. 2, an opening 28 is formed in the front of the case 15. The front cover 23 is provided so as 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 able to rotate around its rear end. Because the internal space 12S is surrounded by the case 15 and the front cover 23, dust and dirt from the external space are less likely to enter the internal space 12S during printing. In addition, light emitted from a light irradiation device 40 (described later) is less likely to leak into the external space.

[0014] The material and shape of the recording medium 5 used in this embodiment are not particularly limited. For example, the material of the recording medium 5 may be wood, metal, glass, paper, cloth, etc. Furthermore, the shape of the recording medium 5 is not limited to a flat plate shape, and may have various three-dimensional shapes.

[0015] As shown in FIG. 1, a window 23A is provided in the front and upper portions of the front cover 23. The window 23A is formed, for example, from a transparent acrylic plate. The window 23A allows the internal space 12S to be seen from the outside, but is configured to prevent light emitted from a light irradiation device 40 (described later) from leaking to the outside. Here, the window 23A is made of a material that does not transmit ultraviolet rays. Note that the window 23A may be treated to block ultraviolet rays. The user can see inside 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, a table 35, and a control device 70. The carriage 20 is equipped with an ink head 30 and a light irradiation device 40. The guide rail 18, carriage 20, ink head 30, table 35, light irradiation device 40, and control device 70 are provided in an internal space 12S. The guide rail 18 is fixed to a support wall 15A of the case 15 and extends in the main scanning direction Y. The carriage 20 is provided so as to be able to slide on the guide rail 18. The printer 10 includes a carriage movement mechanism 21 (see FIG. 7) that moves the carriage 20 in the main scanning direction. A well-known mechanism can be used for the carriage movement mechanism 21. The carriage movement mechanism 21 may include, for example, a belt to which the carriage 20 is fixed, a pair of left and right pulleys around which the belt is wound, and a motor connected to one of the pulleys. The carriage movement mechanism 21 allows the carriage 20 to move back and forth in the main scanning direction Y along the guide rail 18. As the carriage 20 moves in the main scanning direction Y, the ink head 30 and the light irradiation device 40 move in the main scanning direction Y. The table 35 is disposed below the carriage 20.

[0017] A plurality of ink heads 30 are mounted on the carriage 20. The ink heads 30 are attached to the bottom of the carriage 20. The ink heads 30 are positioned above a table 35. The ink heads 30 eject ink onto a recording medium 5 placed on the table 35. The ink heads 30 are connected to a plurality of ink cartridges 60 by flexible ink tubes (not shown). The ink cartridges 60 are housed inside the case 15. The ink cartridges 60 store ink. The plurality of ink cartridges 60 may store ink of different colors or may store ink of the same color.

[0018] As shown in FIG. 4, the ink head 30 is mounted on the carriage 20 so as to extend in the sub-scanning direction X. The ink head 30 includes multiple left nozzles 31A, multiple right nozzles 31B, and a nozzle surface 31C. The left nozzles 31A and right nozzles 31B are tiny holes from which ink is ejected. The left nozzles 31A and right nozzles 31B are connected to pressure chambers that store ink. Ink is ejected from the left nozzles 31A and right nozzles 31B when the pressure chambers expand or contract due to driving, for example, a piezoelectric element. The left nozzles 31A and right nozzles 31B are formed on the nozzle surface 31C. The nozzle surface 31C faces downward, and the left nozzles 31A and right nozzles 31B eject ink downward. Although three ink heads 30 are shown in FIG. 4, the number of ink heads 30 is not limited to this.

[0019] The left nozzles 31A are aligned in the sub-scanning direction X. The right nozzles 31B are aligned in the sub-scanning direction X and are disposed to the right of the left nozzles 31. A plurality of left nozzles 31A are aligned in a row to form a left nozzle row 33A. Similarly, a plurality of right nozzles 31B are aligned in a row to form a right nozzle row 33B. In FIG. 4, the left nozzle row 33A and the right nozzle row 33B each have 12 nozzles, but in reality, many more nozzles (for example, 300 nozzles) are formed. However, the number of nozzles formed in one nozzle row is not limited. Also, in FIG. 4, the ink head 30 has two nozzle rows, the left nozzles 31A and the right nozzles 31B, but the number of nozzle rows is not limited to this.

[0020] The ink used in this embodiment is a photocurable ink that has the property of being cured when irradiated with light. Here, the photocurable ink is an ultraviolet-curable ink that is cured when irradiated with ultraviolet light. There are no particular restrictions on the components or properties of the photocurable ink. Furthermore, there are no particular restrictions on the color of the photocurable ink.

[0021] As described above, the printer 10 is equipped with a light irradiation device 40 (see FIG. 2). In this embodiment, the light irradiation device 40 is an ultraviolet irradiation device that irradiates ultraviolet rays. The light irradiation device 40 is configured to be able to irradiate light onto the photo-curable ink ejected onto the recording medium 5. As shown in FIG. 4, the light irradiation device 40 is mounted on the carriage 20 via a connecting member 22 and is disposed to the right of the ink head 30. The light irradiation device 40 may also be disposed to the left of the ink head 30.

[0022] As shown in FIG. 4, the light irradiation device 40 includes a plurality of LED elements 43 arranged in a sub-scanning direction X. The plurality of LED elements 43 arranged in a row constitute a light source row 44. The LED elements 43 irradiate light onto the photo-curable ink ejected onto the recording medium 5. The length of the light source row 44 in the sub-scanning direction X is longer than the lengths of the left nozzle row 33A and the right nozzle row 33B in the sub-scanning direction X. Note that, although 18 LED elements 43 are arranged in a row in FIG. 4, in reality, a larger number (for example, 30) of LED elements 43 are arranged in a row.

[0023] Table 35 is a support base that supports the recording medium 5. As shown in FIG. 2, table 35 is configured in a flat plate shape and extends in the main scanning direction Y and the sub-scanning direction X. As shown in FIG. 5, table 35 includes a table main body 35A and a retroreflective material 50, which will be described later. As shown in FIG. 2, a first table moving mechanism 36 and a second table moving mechanism 37 are provided below table 35. The first table moving mechanism 36 is a mechanism that moves table 35 in the sub-scanning direction X. The second table moving mechanism 37 is a mechanism that moves table 35 in the up-down direction Z. The first table moving mechanism 36 and the second table moving mechanism 37 are controlled by a control device 70.

[0024] The printer 10 in this embodiment includes a retroreflective material 50 inside the housing 12. The retroreflective material 50 is a material that reflects incident light back in the direction of incidence. The retroreflective material 50 is provided in at least a portion of the irradiation area inside the housing 12 where light emitted from the light irradiation device 40 strikes. For example, the retroreflective material 50 may be provided at a position overlapping the light irradiation device 40 in a planar view. In this embodiment, the light irradiation device 40 emits light downward. Therefore, most of the light emitted from the light irradiation device 40 reaches the position overlapping the light irradiation device 40 in a planar view. Therefore, the position overlapping the light irradiation device 40 in a planar view is an example of a suitable location for providing the retroreflective material 50. In this embodiment, the retroreflective material 50 is provided on the table 35, which is positioned at a position overlapping the light irradiation device 40 in a planar view. As shown in FIG. 5, the retroreflective material 50 is provided on the top of the table main body 35A and forms the upper surface of the table 35.

[0025] In this embodiment, the retroreflective material 50 is configured using glass spheres 51 as shown in FIG. 6 . The retroreflective material 50 further includes a surface layer 52, a reflective layer 53, and an adhesive layer 54. The surface layer 52 protects the glass spheres 51. In this embodiment, the surface layer 52 is colorless, but it may be colored. The reflective layer 53 reflects light incident on the retroreflective material 50. The adhesive layer 54 bonds the retroreflective material 50 to the table body 35A. The dashed-dotted line in FIG. 6 indicates the light path. Light irradiated from the light irradiation device 40 and incident on the retroreflective material 50 is refracted as it passes through the surface layer 52 and enters the glass spheres 51. The refracted light then reaches the reflective layer 53 and is specularly reflected by the reflective layer 53. The light reflected by the reflective layer 53 is refracted again as it exits the glass spheres 51. The direction of travel of the light after being refracted again is parallel to and opposite to the direction in which the light entered the retroreflective material 50. As described above, the light that is irradiated from the light irradiation device 40 and enters the retroreflective material 50 is refracted and reflected inside the retroreflective material 50, and is reflected in the direction of the light irradiation device 40.

[0026] As shown in FIGS. 2 and 3, the first table moving mechanism 36 includes slide rails 36a and 36b, a conveying member 36c, a ball screw 36d, and a first motor 39A. The slide rails 36a and 36b extend in the sub-scanning direction X. The conveying member 36c is slidable relative to the slide rails 36a and 36b. The conveying member 36c supports the table 35 via other members. The conveying member 36c is connected to a 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). When the first motor 39A is driven, the ball screw 36d rotates, causing the conveying member 36c to slide in the sub-scanning direction X along the slide rails 36a and 36b. This causes the table 35 to move in the sub-scanning direction X.

[0027] As shown in Fig. 2, the second table moving mechanism 37 includes a height adjustment member 37a and a second motor 39B (see Fig. 7). The height adjustment member 37a is provided on the underside of the table 35. The height adjustment member 37a is connected to the second motor 39B. When the second motor 39B is driven, the height of the height adjustment member 37a changes, and the height of the table 35 also changes. In other words, the table 35 moves in the vertical direction Z.

[0028] The control device 70 is a device that controls printing on 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 moving mechanism 21, the ink head 30, the light irradiation device 40, the first motor 39A of the first table moving mechanism 36, and the second motor 39B of the second table moving mechanism 37.

[0029] As shown in FIG. 7, the control device 70 includes a print control unit 71, a light source control unit 72, and a movement control unit 73. The functions of each unit of the control device 70 are realized by a program. The print control unit 71 is a unit that controls the carriage movement mechanism 21 and the ink head 30 to form an image on the recording medium 5. The light source control unit 72 controls the light irradiation device 40. The light source control unit 72 is a unit that irradiates light onto the photo-curable ink ejected onto the recording medium 5 to cure the photo-curable ink. The movement control unit 73 is a unit that controls the first motor 39A and the second motor 39B to move the recording medium 5 in the sub-scanning direction X and the up-down direction Z.

[0030] When printing on the recording medium 5, the printer 10 simultaneously ejects photocurable ink from the ink head 30 and emits light from the light irradiation device 40 while moving the carriage 20 in the main scanning direction Y. When the carriage 20 is directly above the recording medium 5, light from the light irradiation device 40 is irradiated onto the recording medium 5. This allows the photocurable ink ejected onto the recording medium 5 to be cured. However, as shown in FIG. 5 , when the carriage 20 moves to the side of the recording medium 5, the light emitted from the light irradiation device 40 is irradiated onto the table 35 instead of the recording medium 5. The light that reaches the table 35 is reflected by the top surface of the table 35. As described above, in this embodiment, the top surface of the table 35 is made of a retroreflective material 50. Therefore, when the light emitted from the light irradiation device 40 reaches the table 35, it is reflected back toward the light irradiation device 40. In other words, the table 35 makes it difficult for the light emitted from the light irradiation device 40 to reach the ink head 30.

[0031] The inkjet printer 10 according to this embodiment is provided with a retroreflective material 50 in at least a portion of the irradiation range of the light irradiation device 40 inside the housing 12. The retroreflective material 50 is a member that reflects incident light back in the direction of incidence. As a result, light that is irradiated from the light irradiation device 40 and reaches the retroreflective material 50 is reflected back to the light irradiation device 40. In other words, the light irradiated from the light irradiation device 40 is less likely to reach the ink head 30. This can prevent the photocurable ink adhering to the surface of the ink head 30 from thickening. This can prevent malfunction of the ink head 30.

[0032] In this embodiment, the upper surface of the table 35 is made of a retroreflective material 50. The table 35 is provided below the light irradiation device 40, and in a plan view, the light irradiation device 40 and the table 35 overlap. Therefore, most of the light irradiated from the light irradiation device 40 reaches the table 35. Because the upper surface of the table 35 is made of a retroreflective material 50, most of the light irradiated from the light irradiation device 40 is reflected back toward the light irradiation device 40. In other words, the light irradiated from the light irradiation device 40 is less likely to reach the ink head 30. This can prevent the photocurable ink adhering to the surface of the ink head 30 from thickening. This can prevent malfunction of the ink head 30.

[0033] Although one embodiment of the present invention has been described above, the embodiment is merely an example, and various other embodiments are possible.

[0034] The height of the table 35 is adjusted according to the thickness of the recording medium 5 placed on the table 35. When the recording medium 5 is thick, the height of the table 35 is lower than when the recording medium 5 is thin. That is, the distance H (hereinafter referred to as the gap) between the light irradiation device 40 and the table 35 shown in FIG. 8 becomes larger. If the gap is large, the light emitted from the light irradiation device 40 and reflected by the table 35 reaches the ink head 30 even if the reflection angle of the light is small. That is, if the gap is large, the light emitted from the light irradiation device 40 easily reaches the ink head 30. Therefore, to fill the gap, a jig 80 may be placed on the side of the recording medium 5. As a result, light reflected by the upper surface of the jig 80 at a small reflection angle does not reach the ink head 30. Furthermore, the upper surface of the jig 80 may be made of a retroreflective material 50. As a result, light emitted from the light irradiation device 40 and reaching the upper surface of the jig 80 is reflected back to the light irradiation device 40. Therefore, by placing a jig 80 whose upper surface is made of retroreflective material 50 on the side of the recording medium 5, the light irradiated from the light irradiation device 40 is less likely to reach the ink head 30 than when the upper surface of the table 35 is made of retroreflective material 50.

[0035] In FIG. 8, only the top surface of the jig 80 is made of retroreflective material 50, but both the top surface of the jig 80 and the top surface of the table 35 may be made of retroreflective material 50.

[0036] In the above embodiment, the entire top surface of the table 35 is made of retroreflective material 50. However, the entire top surface of the table 35 does not necessarily need to be made of retroreflective material 50; only a portion of the top surface of the table 35 may be made of retroreflective material 50. For example, as shown in FIG. 9 , only the end portion of the top surface of the table 35 in the main scanning direction Y may be made of retroreflective material 50. The recording medium 5 is generally placed in the center of the table 35, and is rarely placed at the end portion of the table 35. Therefore, the light irradiated from the light irradiation device 40 is unlikely to strike the center portion of the top surface of the table 35, while the light irradiated from the light irradiation device 40 is likely to strike the end portion of the top surface of the table 35 in the main scanning direction Y. Therefore, compared to when the entire top surface of the table 35 is made of retroreflective material 50, the amount of retroreflective material 50 used can be reduced while suppressing light reflection toward the ink head 30 to the same degree.

[0037] The position where the retroreflective material 50 is provided is not limited to the upper surface of the table 35 or the upper surface of the jig 80. The retroreflective material 50 may be provided on another member that is hit by the light irradiated from the light irradiation device 40, as long as it is provided in at least a part of the irradiation range that is hit by the light irradiated from the light irradiation device 40.

[0038] The configuration of the retroreflective material 50 is not limited to the above embodiment. Instead of the glass spheres 51, a microprism-type retroreflective material using transparent triangular pyramids made of glass or other material may also be used. [Explanation of symbols]

[0039] 5. Recording media 10 Printers 12. Case 20 carriages 30 ink head 31A Left nozzle 31B Right nozzle 31C Nozzle surface 35 tables 40 Light irradiation device 50 Retroreflective material 80 Jig

Claims

1. a box-shaped housing; a table disposed inside the housing and on which a recording medium is placed; a carriage disposed inside the housing and above the table, and movable in a main scanning direction; an ink head mounted on the carriage; a plurality of nozzles formed on a lower surface of the ink head for ejecting photocurable ink toward the recording medium; a light irradiation device mounted on the carriage so as to be disposed to the side of the ink head, and configured to irradiate light toward the photo-curable ink ejected onto the recording medium; a retroreflective material provided in at least a part of the irradiation range of the light irradiation device inside the housing.

2. The inkjet printer according to claim 1 , wherein the retroreflective material is disposed at a position overlapping the light irradiation device in a plan view.

3. a jig placed on the table so as to be disposed to the side of the recording medium; The inkjet printer according to claim 1 , wherein an upper surface of the jig is made of the retroreflective material.

4. The printer according to claim 1 , wherein at least a portion of the top surface of the table is made of the retroreflective material.

5. 2. The printer according to claim 1, wherein the edge of the top surface of the table in the main scanning direction is made of the retroreflective material.

Images