Inkjet printer

Abstract

To discharge more ink for improving an image quality.SOLUTION: A printer 10 comprises: a left-side second nozzle row 34A in which a plurality of left-side second nozzles 32A, which discharge to a recording medium 5 second ink that is used in forming a foundation on which an image is not yet formed, are arranged in a sub scanning direction X; a carriage 20, provided to be movable in a main scanning direction Y, which includes the left-side second nozzle row 34A; one ultraviolet irradiation device 40, provided in the carriage 20, which has a light source 43; and a control device 70. The control device 70 has a printing control part 71 that makes a left-side first nozzle 31A discharge first ink which is used in forming an image only when the carriage 20 moves in a forward direction Y1, and makes the left-side second nozzles 32A discharge the second ink when the carriage 20 moves in the forward direction Y1 and in a backward direction Y2. The ultraviolet irradiation device 40 is arranged closer to the backward direction Y2 than the left-side second nozzle row 34A.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Inkjet printers (hereinafter sometimes simply referred to as "photocurable printers") that use photocurable ink (hereinafter sometimes simply referred to as "photocurable ink") have been known. For example, in a photocurable printer shown in Patent Document 1, photocurable ink is ejected from an ink head, and the ejected photocurable ink is irradiated with light (e.g., ultraviolet light) from a light source of a light irradiation device. This causes the photocurable ink to harden on the recording medium to form an ink layer, allowing a desired image to be printed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5817059 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the photocurable printer shown in Patent Document 1, two light irradiation devices each having a light source are provided, one on each side of the ink head (i.e., one side and the other side in the main scanning direction). This allows the photocurable ink used for image formation (hereinafter sometimes referred to as image forming ink) to be ejected in both the forward direction from one side of the main scanning direction to the other and the return direction from the other side of the main scanning direction to one side, and the ejected photocurable ink can be immediately irradiated with light from the light source to cure the photocurable ink.

[0005] Some photocuring printers are equipped with only one light irradiation device. If the timing of irradiating the ejected image forming ink with light differs, the image forming ink will harden unevenly, which may result in a deterioration in the quality of the formed image. For this reason, photocuring printers equipped with one light irradiation device eject image forming ink from the ink head only in the forward direction to form an image on the recording medium.

[0006] Here, before ejecting the image forming ink onto the recording medium, a photocurable ink used for forming a base is ejected onto the recording medium, and a photocurable ink used for surface finishing after image formation (hereinafter, these inks may be referred to as image quality improving ink) is ejected onto the formed image. These image quality improving inks are required to be ejected at a higher concentration than the image forming ink. Since there is an upper limit to the amount of ink ejected from each nozzle of the ink head, it is considered to eject the above ink from multiple nozzle rows in order to increase the concentration. However, since there is a limit to the number of nozzle rows that can be installed in a printer (determined depending on the model of the printer), if an attempt is made to increase the number of nozzle rows that eject a specific image quality improving ink, a problem may occur in that the number of nozzle rows that eject the image forming ink and other image quality improving inks will decrease.

[0007] The present invention has been made in consideration of these points, and its object is to provide an inkjet printer that can eject more image quality improving ink without increasing the number of nozzle rows that eject image quality improving ink used for base formation before image formation or surface finishing after image formation. [Means for solving the problem]

[0008] The inventors of the present application realized that the image quality of the image is hardly affected by the ink for improving image quality even if the timing of light irradiation is different after the ink for improving image quality is ejected onto the recording medium. Therefore, in a printer capable of ejecting the ink for forming image quality and the ink for improving image quality in the forward direction, the inventors discovered that the ink for improving image quality can be ejected in a larger amount (i.e., at a higher concentration) by further ejecting the ink for improving image quality in the return direction.

[0009] The inkjet printer of the present invention comprises a mounting table on which a recording medium is placed, a first nozzle row having a plurality of first nozzles arranged in a first direction for ejecting a first ink that is photocurable and is used for image formation onto the recording medium, a second nozzle row having a plurality of second nozzles arranged in the first direction for ejecting a second ink that is photocurable and is used for base formation before image formation or surface finishing after image formation onto the recording medium, a carriage that is movable in a second direction intersecting the first direction and includes the first nozzle row and the second nozzle row, a moving device that is capable of moving one of the mounting table and the carriage relatively in the first direction with respect to the other, one light irradiation device that is provided on the carriage and has a light source that irradiates light onto an area of ​​the recording medium onto which the first ink and the second ink are ejected, and a control device. The control device includes a print control unit configured to eject the first ink from the first nozzles only when the carriage moves in the forward direction, and to eject the second ink from the second nozzles when the carriage moves in the forward direction and the return direction, when the direction from one side of the second direction to the other side of the second direction is defined as a forward direction and a return direction, respectively, and a light source control unit that irradiates light from the light source. The light irradiation device is provided on the return direction side of the first nozzle row and the second nozzle row.

[0010] According to the inkjet printer of the present invention, the print control unit ejects the first ink (e.g., an ink for forming an image) from the first nozzle only when the carriage moves in the forward direction. Here, since the light irradiation device is provided on the return direction side of the first nozzle row and the second nozzle row, the first ink ejected onto the recording medium can be immediately irradiated with light from the light source of the light irradiation device. Also, the print control unit ejects the second ink (e.g., an ink for improving image quality) from the second nozzle not only when the carriage moves in the forward direction but also when the carriage moves in the return direction. In this way, since the second ink can be ejected onto the recording medium while the carriage moves in the forward direction and the return direction, a larger amount of the second ink can be ejected onto the recording medium without increasing the number of second nozzle rows that eject the second ink. Effect of the Invention

[0011] According to the present invention, it is possible to provide an inkjet printer that can eject a larger amount of image quality improving ink without increasing the number of nozzle rows that eject image quality improving ink. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of a printer according to an embodiment; [Diagram 2] 1 is a front view of a printer with a front cover open according to an embodiment; [Diagram 3] FIG. 2 is a plan view of a printer with a front cover and a case removed according to an embodiment. [Figure 4] FIG. 2 is a schematic diagram showing a configuration of a surface of a carriage facing a recording medium according to an embodiment. [Diagram 5] FIG. 1 is a block diagram of a printer according to an embodiment. [Figure 6] 11 is an example of a plan view showing a schematic relationship between the second ink ejected in the forward direction and the second ink ejected in the return direction. FIG. [Figure 7]11 is another example of a plan view showing a schematic relationship between the second ink ejected in the forward direction and the second ink ejected in the return direction. FIG.

[0013] An inkjet printer (hereinafter referred to as "printer") according to an embodiment of the present invention will be described below with reference to the drawings. Note that the embodiment described here is, of course, not intended to limit the present invention in any particular way. Furthermore, the same reference numerals are used for members and parts that perform the same function, and duplicate descriptions will be omitted or simplified as appropriate.

[0014] FIG. 1 is a perspective view of a printer 10 according to the present embodiment. The printer 10 prints on a recording medium 5 (see FIG. 2). In the following description, when the printer 10 is viewed from the front, the side away from the printer 10 is the front, and the side approaching the printer 10 is the rear. The terms left, right, top, and bottom refer to the left, right, top, and bottom of the printer 10 when viewed from the front. The symbols F, Rr, L, R, U, and D in the drawings refer to the front, back, left, right, top, and bottom, respectively. The symbol Y in the drawings 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-rear 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. The sub-scanning direction X is an example of a first direction. The main scanning direction Y is an example of a second direction. Further, the forward direction Y1 indicates the direction from right to left in the main scanning direction Y, the return direction Y2 indicates the direction from left to right in the main scanning direction Y, the forward direction X1 indicates the direction from upstream to downstream in the sub-scanning direction X (here, the direction from back to front), and the return direction X2 indicates the direction from downstream to upstream in the sub-scanning direction X (here, the direction from front to back). However, the above directions are merely defined for the convenience of explanation, and do not limit in any way the installation mode of the printer 10, nor do they limit in any way the present invention.

[0015] 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 mobile phone cases, small electronic devices, small parts such as key holders, photo frames, and pens, daily necessities, accessories, etc. The material forming the recording medium 5 may be not only paper such as plain paper or inkjet printing paper, but also resins such as polyvinyl chloride (PVC), acrylic resin, polycarbonate, polystyrene, polyethylene, polyester, polyethylene terephthalate (PET), and acrylonitrile-butadiene-styrene (ABS) copolymer, metals such as aluminum and stainless steel, carbon, pottery, ceramic, glass, rubber, leather, wood, etc.

[0016] As shown in FIG. 1, the printer 10 includes a box-shaped housing 12. The housing 12 has an internal space 12S. The housing 12 includes a case 15, a front cover 23, and an operation panel 25. An opening 28 (see FIG. 2) 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 rotatable about its rear end. By rotating the front cover 23 upward, the internal space 12S of the housing 12 communicates with the external space. The internal space 12S is a space where printing is performed on a recording medium 5 by an ink head 30 (see FIG. 2), which will be described later. In this way, the internal space 12S where printing is performed is formed by being surrounded by the case 15 and the front cover 23, so that dust and dirt from the external space are less likely to enter the internal space 12S during printing, and light irradiated from an ultraviolet irradiation device 40 (see FIG. 2), which will be described later, is less likely to leak into the external space.

[0017] 1, a window 23A is provided in the front and upper part of the front cover 23. The window 23A is formed of, for example, a transparent acrylic plate. The window 23A is treated so that light from the external space (for example, ultraviolet light) does not reach the internal space 12S. The user can view the inside of the housing 12 through the window 23A.

[0018] The operation panel 25 is provided on the case 15. The operation panel 25 is provided on the right side of the top surface of the case 15. The operation panel 25 is a panel on which the user performs operations related to printing of images. The operation panel 25 is provided with a display screen 25A on which information related to printing, such as the type of printing (e.g., whether or not there is a glossy finish), the resolution, the printing status, and the like, and input buttons 25B for setting information related to printing and the recording medium 5.

[0019] 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 an internal space 12S. The guide rail 18 is disposed in a case 15. As shown in FIG. 3, 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 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 movement mechanism 21 (see FIG. 5). The carriage movement mechanism 21 is controlled by a 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.

[0020] As shown in Fig. 2, the carriage 20 is equipped with a plurality of ink heads 30. The ink heads 30 are disposed above a table 35, which will be described later. The ink heads 30 eject photocurable ink (photocurable ink) onto the recording medium 5 placed on the table 35. Each ink head 30 is in communication with an ink cartridge 50 housed within the case 15 by a flexible ink tube (not shown). Each ink cartridge 50 stores photocurable ink.

[0021] As shown in FIG. 4, the ink head 30 includes a first ink head 31 that ejects a first ink used in image formation, and a second ink head 32 that ejects a second ink used in forming a base layer before image formation or for surface finishing after image formation. The first ink head 31 and the second ink head 32 are mounted on a carriage 20. That is, the carriage 20 includes a left first nozzle row 33A, a right first nozzle row 33B, a left second nozzle row 34A, and a right second nozzle row 34B, which will be described later. The first ink head 31 and the second ink head 32 are arranged at the same position in the sub-scanning direction X. The first ink head 31 and the second ink head 32 may be arranged at positions shifted from each other in the sub-scanning direction X. The first ink head 31 and the second ink head 32 are formed in a shape in which the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. The first ink head 31 and the second ink head 32 are formed in the same shape and size. The first ink head 31 includes a plurality of left first nozzles 31A aligned in the sub-scanning direction X, a plurality of right first nozzles 31B aligned in the sub-scanning direction X and located to the right of the left first nozzles 31A, and a first nozzle surface 31C in which the left first nozzles 31A and the right first nozzles 31B are formed. The plurality of left first nozzles 31A are aligned in a row to form a left first nozzle row 33A. The plurality of right first nozzles 31B are aligned in a row to form a right first nozzle row 33B. The left first nozzles 31A and the right first nozzles 31B eject the first ink. The second ink head 32 includes a plurality of left second nozzles 32A aligned in the sub-scanning direction X, a plurality of right second nozzles 32B aligned in the sub-scanning direction X and located to the right of the left second nozzles 32A, and a second nozzle surface 32C in which the left second nozzles 32A and the right second nozzles 32B are formed. A plurality of left second nozzles 32A are arranged in a row to form a left second nozzle row 34A. A plurality of right second nozzles 32B are arranged in a row to form a right second nozzle row 34B. The left second nozzles 32A and the right second nozzles 32B eject the second ink. The distance in the sub-scanning direction X between the left second nozzles 32A is the same as the distance in the sub-scanning direction X between the right second nozzles 32B, and this distance is referred to as the nozzle distance LN.Here, the distance between nozzles in the sub-scanning direction X is the distance between the centers of the nozzles. In FIG. 4, ink head 30 is shown with 12 nozzles, but in reality, a larger number (for example, 180 nozzles) are formed. However, the number of nozzles is not limited in any way. Furthermore, the number of ink heads 30 is not limited to three. Furthermore, ink head 30 has two nozzle rows, but the number of nozzle rows may be one or three or more.

[0022] The first ink is an ink used for image formation (i.e., image quality forming ink). The first ink is photocurable. That is, the first ink is a photocurable ink that has the property of being cured when irradiated with light (e.g., ultraviolet light). The first ink is, for example, a process color ink. Examples of the process color ink include cyan ink, magenta ink, yellow ink, black ink, light cyan ink, and light magenta ink. Cyan ink, magenta ink, yellow ink, and black ink are ejected from the left first nozzle 31A and the right first nozzle 31B of the first ink head 31 of this embodiment, respectively.

[0023] The second ink is an ink used for forming a base layer before image formation or for surface finishing after image formation (i.e., an ink for improving image quality). The second ink is photocurable. That is, the second ink is a photocurable ink that has the property of being cured when irradiated with light (e.g., ultraviolet light). The ink used for forming the base layer before image formation is, for example, a primer ink or a white ink. The primer ink is adhesive. The ink used for surface finishing after image formation (i.e., forming a surface layer) is, for example, a gloss ink. In this embodiment, white ink is ejected from the left second nozzle 32A of the second ink head 32, and gloss ink is ejected from the right second nozzle 32B.

[0024] As shown in FIG. 2, the printer 10 includes one ultraviolet irradiation device 40. The ultraviolet irradiation device 40 irradiates light (typically ultraviolet light). The ultraviolet irradiation device 40 is configured to be able to irradiate light (here, ultraviolet light) to an area (i.e., a printing area) of the recording medium 5 where the first ink and the second ink are discharged. The ultraviolet irradiation device 40 is configured to be able to irradiate light toward the first ink and the second ink discharged onto the recording medium 5. The ultraviolet irradiation device 40 includes a light source 43 that irradiates light. In this embodiment, the ultraviolet irradiation device 40 includes a plurality of light sources 43 arranged in the sub-scanning direction X. The light source 43 irradiates light (here, ultraviolet light) to an area where the first ink and the second ink are discharged onto the recording medium 5. Note that, although 18 light sources are illustrated in FIG. 4, a larger number of light sources (for example, 30) are actually provided. The light source 43 is, for example, an LED. The ultraviolet irradiation device 40 is an example of a light irradiation device. As shown in FIG. 2, the ultraviolet irradiation device 40 is mounted on the carriage 20. The ultraviolet irradiating device 40 is disposed above a table 35, which will be described later. As shown in Fig. 4, the ultraviolet irradiating device 40 is disposed on the return direction Y2 side (here, to the right) of the ink head 30. That is, the ultraviolet irradiating device 40 is disposed to the right of the left first nozzle row 33A, the right first nozzle row 33B, the left second nozzle row 34A, and the right second nozzle row 34B.

[0025] As shown in FIG. 4, in the ultraviolet irradiation device 40, a plurality of light sources 43 are arranged in a row to form a light source row 44. The length of the light source row 44 in the sub-scanning direction X is longer than the length of the left second nozzle row 34A in the sub-scanning direction X. The light source row 44 includes a first light source row 44A in which some of the light sources 43 are arranged in the sub-scanning direction X, and a second light source row 44B in which the light sources 43 are arranged in the sub-scanning direction X downstream (in this case, forward) of the first light source row 44A and the other parts of the light sources 43 are arranged in the sub-scanning direction X. The first light source row 44A is located to the side of the left second nozzle row 34A in the main scanning direction Y. The first light source row 44A is arranged at a position aligned with the left second nozzle row 34A in the sub-scanning direction X. The second light source row 44B is located downstream (in this case, forward) of the left second nozzle row 34A in the sub-scanning direction X. That is, the left second nozzle 32A is not arranged to the side of the second light source row 44B in the main scanning direction Y. In this embodiment, the number of light sources 43 in the first light source array 44A is greater than the number of light sources 43 in the second light source array 44B. The number of light sources 43 in the second light source array 44B may be the same as or greater than the number of light sources 43 in the first light source array 44A. The first light source array 44A is an example of a first light source section, and the second light source array 44B is an example of a second light source section.

[0026] As shown in FIG. 2, the printer 10 is a so-called flatbed type printer. The printer 10 includes a table 35 arranged below the carriage 20, a first table moving mechanism 36, and a second table moving mechanism 37. The table 35, the first table moving mechanism 36, and the second table moving mechanism 37 are provided in the internal space 12S. The table 35 is an example of a mounting table. The recording medium 5 is mounted 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 moving mechanism 36. The table 35 is configured to be movable in the up-down direction Z by the second table moving mechanism 37.

[0027] As shown in FIG. 2, 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 (see also FIG. 5). The slide rails 36a and 36b extend in the sub-scanning direction X. The conveying member 36c is provided so as to be slidable relative to the slide rails 36a and 36b. Above the conveying member 36c, the table 35 is supported via other members. The conveying 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 the control device 70 and is controlled by the control device 70. When the first motor 39A is driven, the conveying member 39c moves in the sub-scanning direction X along the slide rails 36a, 36b by rotation of the ball screw 36d. This causes the table 35 to move in the sub-scanning direction X. The first table moving mechanism 36 is an example of a moving device.

[0028] As shown in FIG. 2, the second table moving mechanism 37 includes a height adjustment member 37a and a second motor 39B (see FIG. 5). The height adjustment member 37a is provided on the lower surface 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 is 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.

[0029] As shown in FIG. 5, 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 hardware configuration of the microcomputer is not particularly limited, but includes, for example, an interface (I / F) that receives print data and the like from an external device such as a host computer, a central processing unit (CPU) that executes instructions of a control program, a read only memory (ROM) that stores the program executed by the CPU, a random access memory (RAM) used as a working area for expanding the program, and a storage device such as a memory that stores the program and various data. As shown in FIG. 2, the control device 70 is provided inside the case 15. However, the control device 70 does not have to be provided inside the case 15. For example, the control device 70 may be a computer or the like installed outside the case 15. In this case, the control device 70 is connected to the printer 10 so as to be able to communicate with it via wire or wirelessly.

[0030] 5, the control device 70 is communicatively connected to the operation panel 25, the carriage moving mechanism 21, the first ink head 31, the second ink head 32, the ultraviolet irradiation device 40, the first motor 39A of the first table moving mechanism 36 (see FIG. 2), and the second motor 39B of the second table moving mechanism 37 (see FIG. 2). The control device 70 controls the carriage moving mechanism 21, the first ink head 31, the second ink head 32, the ultraviolet irradiation device 40, the first motor 39A, and the second motor 39B.

[0031] The control device 70 controls the amount and timing of the first ink discharged from the left first nozzle 31A and the right first nozzle 31B of the first ink head 31. The control device 70 controls the amount and timing of the second ink discharged from the left second nozzle 32A and the right second nozzle 32B of the second ink head 32. The control device 70 controls the amount and timing of the ultraviolet light emitted from the light source 43 of the ultraviolet irradiation device 40. The control device 70 controls the movement of the carriage 20 in the main scanning direction Y. The control device 70 controls the movement of the table 35 in the sub-scanning direction X.

[0032] As shown in FIG. 5, the control device 70 includes a print control unit 71, a light source control unit 73, and a movement control unit 75. The functions of each unit of the control device 70 are realized by a program. For example, the program is written from a PC via a LAN into a ROM mounted on a board inside the printer 10, or written from a PC using a dedicated writing tool into an FPGA mounted on a board inside the printer 10. For example, the program is downloaded to a PC via the Internet. The functions of each unit of the control device 70 may be realized by a processor and / or a circuit. The specific functions of each unit will be described later.

[0033] The print control unit 71 is a part that forms a base layer, an image, and a surface layer on the recording medium 5. The print control unit 71 controls the carriage moving mechanism 21, the first ink head 31, and the second ink head 32. The print control unit 71 is configured to eject the first ink from the left first nozzle 31A and the right first nozzle 31B of the first ink head 31 only when the carriage 20 moves in the forward direction Y1. The print control unit 71 is configured to eject the second ink from the left second nozzle 32A and the right second nozzle 32B of the second ink head 32 when the carriage 20 moves in the forward direction Y1 and the return direction Y2. The print control unit 71 may be configured to eject the second ink from the left second nozzle 32A and the right second nozzle 32B of the second ink head 32 only when the carriage 20 moves in the forward direction Y1. For example, when white ink is ejected from the left second nozzle 32A of the second ink head 32 and gloss ink is ejected from the right second nozzle 32B, one of the inks is ejected onto the recording medium 5 in the forward direction Y1 and the return direction Y2. That is, when forming a base layer, white ink is ejected from the left second nozzle 32A but gloss ink is not ejected from the right second nozzle 32B, and when finishing the surface, gloss ink is ejected from the right second nozzle 32B but white ink is not ejected from the left second nozzle 32A.

[0034] The light source control unit 73 controls the light source 43 of the ultraviolet irradiation device 40. The light source control unit 73 is a part that irradiates the first ink and the second ink with light from the light source 43 to cure the first ink and the second ink. The light source control unit 73 controls the amount of light of each of the light sources 43 of the first light source row 44A and the second light source row 44B of the ultraviolet irradiation device 40. When the first ink is discharged from at least one of the left first nozzle 31A and the right first nozzle 31B of the first ink head 31 while the carriage 20 moves in the forward direction Y1, the light source control unit 73 irradiates light from each of the light sources 43 of the first light source row 44A and the second light source row 44B of the ultraviolet irradiation device 40 toward the first ink in the forward direction Y1 and the return direction Y2 of the carriage 20. When the carriage 20 moves in the forward direction Y1 and the return direction Y2 and the second ink is ejected from either the left second nozzle 32A or the right second nozzle 32B of the second ink head 32, the light source control unit 73 irradiates light from each light source 43 of the first light source row 44A and the second light source row 44B of the ultraviolet irradiation device 40 toward the second ink in the forward direction Y1 and the return direction Y2 of the carriage 20. In addition, when the second ink is ejected from either the left second nozzle 32A or the right second nozzle 32B of the second ink head 32 when the carriage 20 moves in the forward direction Y1 and the return direction Y2, the light source control unit 73 may not irradiate light from each light source 43 of the first light source row 44A of the ultraviolet irradiation device 40 toward the second ink in the forward direction Y1 of the carriage 20, but may irradiate light from each light source 43 of the second light source row 44B toward the second ink, and may irradiate light from each light source 43 of the first light source row 44A and the second light source row 44B toward the second ink in the return direction Y2 of the carriage 20.

[0035] The movement control unit 75 is a unit that moves the recording medium 5 in the sub-scanning direction X (i.e., the forward direction X1 and the return direction X2). The movement control unit 75 controls the first motor 39A. After the carriage 20 has made one reciprocating movement in the forward direction Y1 and the return direction Y2, the movement control unit 75 controls the first motor 39A to move the table 35 in the sub-scanning direction X by the distance LP for one pass. This causes the recording medium 5 to move in the sub-scanning direction X by the distance LP for one pass. Note that the movement control unit 75 may move the recording medium 5 in the sub-scanning direction X (the forward direction X1 here) by a distance LS that is shorter than the distance LP for one pass after the carriage 20 has moved in the forward direction Y1 and before it moves in the return direction Y2. In this case, the movement control unit 75 moves the recording medium 5 in the sub-scanning direction X (the forward direction X1 here) by the difference between the distance LP for one pass and the distance LS after the carriage 20 has moved in the return direction. Furthermore, the movement control unit 75 may move the recording medium 5 in the sub-scanning direction X (here, the forward direction X1) a distance LNH (e.g., a distance LDH half the dot pitch LDP of the printing resolution) that is shorter than the nozzle distance LN (see FIG. 4) after the carriage 20 has moved in the forward direction Y1 and before it moves in the return direction Y2. In this case, the movement control unit 75 moves the recording medium 5 in the sub-scanning direction X (here, the forward direction X1) a distance equal to the difference between the distance LP for one pass and the distance LNH (e.g., the distance LDH) after the carriage 20 has moved in the return direction.

[0036] 6 is a plan view showing a schematic relationship between the second ink 8A discharged in the forward direction Y1 and cured, and the second ink 8B discharged in the return direction Y2, and shows the state where light is irradiated from each light source 43 of the first light source row 44A of the ultraviolet irradiation device 40 toward the second ink when the carriage 20 moves in the forward direction Y1 and the return direction Y2. As shown in FIG. 6, the second ink 8A discharged in the forward direction Y1 is irradiated with light from the light sources 43 of the first light source row 44A of the ultraviolet irradiation device 40 immediately after landing on the recording medium 5, and therefore is cured without spreading much on the recording medium 5. On the other hand, the second ink 8B ejected in the return direction Y2 after the recording medium 5 has moved a distance LDH (half the dot pitch LDP of the printing resolution, i.e., equivalent to half the distance between the vertices of adjacent dots of the second ink 8A in the sub-scanning direction X) in the sub-scanning direction X spreads and hardens on the recording medium 5 because it takes time for the second ink 8B to be irradiated with light from the light source 43 of the first light source row 44A of the ultraviolet irradiation device 40 after it hits the recording medium 5. This allows the recording medium 5 to be filled with the second ink over a wide area.

[0037] FIG. 7 is a plan view showing a relationship between the second ink 8A discharged in the forward direction Y1 and cured, and the second ink 8B discharged in the return direction Y2, and shows a case where light is irradiated from each light source 43 of the first light source row 44A of the ultraviolet irradiation device 40 to the second ink only when the carriage 20 moves in the return direction Y2. As shown in FIG. 7, the second ink 8A discharged in the forward direction Y1 spreads and is cured on the recording medium 5 because it takes time from the time when the ink 8A lands on the recording medium 5 until it is irradiated with light from the light source 43 of the first light source row 44A of the ultraviolet irradiation device 40. Similarly, the second ink 8B discharged in the return direction Y2 after the recording medium 5 moves by a distance LDH in the sub-scanning direction X spreads and is cured on the recording medium 5 because it takes time from the time when the ink 8A lands on the recording medium 5 until it is irradiated with light from the light source 43 of the first light source row 44A of the ultraviolet irradiation device 40. This allows the recording medium 5 to be filled with the second ink over a wider range. 6 and 7, the recording medium 5 is moved in the sub-scanning direction X by the distance LDH, but it is sufficient if the distance LS is shorter than the distance LP for one pass (for example, the distance LNH shorter than the nozzle distance LN).

[0038] As described above, according to the printer 10 of this embodiment, the print control unit 71 ejects the first ink (e.g., image forming ink) from the left first nozzle 31A and the right first nozzle 31B only when the carriage 20 moves in the forward direction Y1. Here, the ultraviolet irradiation device 40 is provided on the return direction Y2 (here, to the right) side of the left first nozzle row 33A, the right first nozzle row 33B, the left second nozzle row 34A, and the right second nozzle row 34B, so that the first ink ejected onto the recording medium 5 can be immediately irradiated with light from the light source 43 of the ultraviolet irradiation device 40. Furthermore, the print control unit 71 ejects the second ink (e.g., image quality improving ink) from the left second nozzle 32A and the right second nozzle 32B not only when the carriage 20 moves in the forward direction Y1 but also when the carriage 20 moves in the return direction Y2. In this way, the second ink can be ejected onto the recording medium 5 while the carriage 20 moves in the forward direction Y1 and the return direction Y2, so that more second ink can be ejected onto the recording medium 5 without increasing the number of the left second nozzle row 34A and the right second nozzle row 34B that eject the second ink.

[0039] According to the printer 10 of this embodiment, the control device 70 has a movement control unit 75 that moves the recording medium 5 in the sub-scanning direction X by a distance LS that is shorter than the distance LP for one pass after the carriage 20 moves in the forward direction Y1 and before it moves in the return direction Y2. This makes it possible to shift, in the sub-scanning direction X, the landing position of the second ink ejected onto the recording medium 5 in the forward direction Y1 from the landing position of the second ink ejected onto the recording medium 5 in the return direction Y2. In other words, the second ink can be ejected over a wide range onto the recording medium 5.

[0040] According to the printer 10 of this embodiment, the movement control unit 75 moves the recording medium 5 in the sub-scanning direction X by a distance LNH shorter than the nozzle distance LN after the carriage 20 moves in the forward direction Y1 and before it moves in the return direction Y2. This makes it possible to shift in the sub-scanning direction X the landing position of the second ink ejected onto the recording medium 5 in the forward direction Y1 from the landing position of the second ink ejected onto the recording medium 5 in the return direction Y2. In other words, the second ink can be ejected over a wide range onto the recording medium 5.

[0041] According to the printer 10 of this embodiment, the movement control unit 75 may move the recording medium 5 in the sub-scanning direction X by a distance LDH that is half the dot pitch LDP of the printing resolution after the carriage 20 moves in the forward direction Y1 and before it moves in the return direction Y2. This makes it possible to shift the landing position of the second ink ejected onto the recording medium 5 in the forward direction Y1 from the landing position of the second ink ejected onto the recording medium 5 in the return direction Y2 by the distance LDH in the sub-scanning direction X. In other words, it is possible to eject the second ink over a wide range onto the recording medium 5.

[0042] According to the printer 10 of this embodiment, the light source control unit 73 may be configured not to emit light from the light source 43 of the first light source row 44A when the carriage 20 moves in the forward direction Y1, and to emit light from the light source 43 of the first light source row 44A when the carriage 20 moves in the return direction Y2. When the first light source row 44A emits light when the carriage 20 moves in the forward direction Y1 and the return direction Y2, the second ink ejected in the forward direction Y1 is immediately irradiated with light, but the second ink ejected in the return direction Y2 is not immediately irradiated with light (light is irradiated when the carriage 20 moves in the forward direction Y1), so that the second ink spreads over a wider range. Therefore, there is a large variation in shape between the second ink ejected and cured in the forward direction Y1 and the second ink ejected and cured in the return direction Y2. Therefore, by not irradiating light from the light sources 43 of the first light source row 44A when the carriage 20 moves in the forward direction Y1, the second ink ejected in the forward direction Y1 is not immediately irradiated with light from the light sources 43, and the second ink spreads on the recording medium 5. As a result, there is less variation in shape between the second ink ejected and cured in the forward direction Y1 and the second ink ejected and cured in the return direction Y2, and image quality is improved.

[0043] According to the printer 10 of this embodiment, the light source control unit 73 may be configured to cause the light source 43 of the second light source row 44B to emit light when the carriage 20 moves in the forward direction Y1 and the return direction Y2. This makes it possible to more reliably cure the first ink and the second ink ejected onto the recording medium 5.

[0044] Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0045] In the above-described embodiment, in the ultraviolet irradiation device 40, the plurality of light sources 43 are arranged in one row to form one light source row 44, but the present invention is not limited to this. The ultraviolet irradiation device 40 may also be configured with the plurality of light source rows 44, with the plurality of light sources 43 arranged in multiple rows (e.g., two to four rows).

[0046] In the above-described embodiment, the first light source row 44A composed of a plurality of light sources 43 and the second light source row 44B composed of a plurality of light sources 43 are provided, but the present invention is not limited to this. For example, as long as light can be irradiated to the range of the left second nozzle row 34A in the sub-scanning direction X and the range downstream of the left second nozzle row 34A in the sub-scanning direction X, the light source 43 may be one, or may be arranged arbitrarily instead of in a row. In addition, when a plurality of light sources 43 are provided, the configuration is not limited to determining the irradiation range by turning on and off each light source 43, and may be configured to determine the irradiation range by providing a shutter that blocks the light of the light source 43, for example.

[0047] In the above-described embodiment, the printer 10 includes a first table moving mechanism 36 as a moving device that moves the table 35 on which the recording medium 5 is placed relative to the carriage 20 in the sub-scanning direction X, thereby moving the recording medium 5 relative to the carriage 20 in the sub-scanning direction X, but is not limited to this. For example, the printer may include a moving device that moves the recording medium 5 relative to the carriage 20 in the sub-scanning direction X by fixing the table 35 to the housing 12 and moving the carriage 20 relative to the table 35 in the sub-scanning direction X.

[0048] The technology disclosed herein can be applied to various types of printers, including the flatbed type printer 10 described in the above embodiment, as well as a so-called roll-to-roll type printer 10 that conveys a roll-shaped recording medium 5 in the sub-scanning direction X. [Explanation of symbols]

[0049] 10 Printer (inkjet printer) 20 Carriage 30 Ink head 31 First ink head 31A Left Nozzle No. 1 31B Right Nozzle No. 1 32 Second ink head 32A Left No. 2 Nozzle 32B Right No. 2 nozzle 33A Left 1st nozzle row 33B Right 1st nozzle row 34A Left 2nd nozzle row 34B Right side second nozzle row 35 Table (Placement stand) 36 First table moving mechanism (moving device) 40 Ultraviolet irradiation device (light irradiation device) 43 Light source 44A 1st light source row 44B 2nd light source row 70 Control device 71 Printing control unit 73 Light source control unit 75 Movement control section Y1 Direction Y2 Return direction

Claims

1. a mounting table on which a recording medium is placed; a first nozzle row in which a plurality of first nozzles are arranged in a first direction and which eject a first ink, the first ink having photocurability and used for image formation, onto the recording medium; a second nozzle row including a plurality of second nozzles arranged in the first direction, the second nozzle row ejecting a second ink onto the recording medium, the second ink having photocurability and used for base formation before image formation or surface finishing after image formation; a carriage provided to be movable in a second direction intersecting the first direction, the carriage including the first nozzle row and the second nozzle row; a moving device that can move one of the mounting table and the carriage relative to the other in the first direction; a light irradiation device provided on the carriage and having a light source that irradiates light onto an area of ​​the recording medium onto which the first ink and the second ink are ejected; A control device, The control device includes: a print control unit configured to eject the first ink from the first nozzles only when the carriage moves in the forward direction, when a direction from one side of the second direction to the other side of the second direction is defined as a forward direction and a direction from the other side of the second direction to one side of the second direction is defined as a return direction, and to eject the first ink from the first nozzles only when the carriage moves in the forward direction, and to eject the second ink from the second nozzles when the carriage moves in the forward direction and in the return direction; a movement control unit that moves the recording medium relatively to the carriage in the first direction by a distance shorter than a nozzle distance, after the carriage moves in the forward direction and before the carriage moves in the return direction, when the distance in the first direction between adjacent second nozzles is defined as a nozzle distance; A light source control unit that causes the light source to emit light, The light irradiation device is provided on the return direction side of the first nozzle row and the second nozzle row.

2. 2. The inkjet printer according to claim 1, wherein the movement control unit moves the recording medium relative to the carriage in the first direction by a distance that is half a dot pitch of a printing resolution after the carriage moves in the forward direction and before the carriage moves in the return direction.

3. The light irradiation device is a first light source unit located to the side of the second nozzle row in the second direction; a second light source unit located downstream of the first light source unit in the first direction, 3. The inkjet printer according to claim 1, wherein the light source control unit is configured to not emit light from the first light source unit when the carriage moves in the forward direction, and to emit light from the first light source unit when the carriage moves in the return direction.

4. 4. The inkjet printer according to claim 3, wherein the light source control unit is configured to cause the second light source unit to emit light when the carriage moves in the forward direction and the return direction.

Images