Inkjet printer

Abstract

To provide a printer capable of suppressing increase in the size of a light source.SOLUTION: A printer 10 includes first nozzle arrays 31 having first nozzles 31A for discharging first ink whose light quantity required for curing is a first light quantity, second nozzle arrays 32 having second nozzles 32A for discharging second ink whose light quantity required for curing is a second light quantity larger than the first light quantity, and a light source 43 for emitting light, wherein at least a part of the first nozzles 31A is deviated to one side in a sub-scanning direction X with respect to the second nozzles 32A, and in the light source 43, when a length of a part positioned on one side in the sub-scanning direction X rather than the first nozzle arrays 31 is represented by a length A, a length of the first nozzle arrays 31, the second nozzle arrays 32 and a part aligned in the main scanning direction Y is represented by a length B, and a length of a part positioned on the other side in the sub-scanning direction X rather than the second nozzle arrays 32 is represented by a length C, the length C is longer than the length A, and the length C is the same as the length B or shorter than the length B.SELECTED DRAWING: Figure 4

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] 4, there exists a printer that includes a first ink head 30A having a first nozzle row 31 in which a plurality of first nozzles 31A that eject a first ink having photocurable properties are aligned in the sub-scanning direction X, a second ink head 30B having a second nozzle row 32 in which a plurality of second nozzles 32A that eject a second ink having photocurable properties are aligned in the sub-scanning direction X and that is biased in the sub-scanning direction X relative to the first ink head 30A, and a light source 43 that irradiates light toward the first ink and the second ink, in which the first nozzle row 31 and the second nozzle row 32 are arranged in a so-called staggered arrangement. With this printer, it is possible to print by moving a recording medium from one side to the other side in the sub-scanning direction X (in the direction of the arrow X1 in FIG. 4) and to print by moving a recording medium from the other side to one side in the sub-scanning direction X (in the direction of the arrow X2 in FIG. 4). In order to reliably cure the first ink and the second ink regardless of the printing direction, the length T of the light source 43 of the light irradiation device in the sub-scanning direction X needs to be longer than the first nozzle row 31 and the second nozzle row 32, which can result in a problem that the light source 43 becomes larger.

[0005] The present invention has been made in consideration of the above points, and its object is to provide an inkjet printer that can print from one side to the other side and from the other side to one side in the sub-scanning direction, and that can prevent the light source from becoming larger. [Means for solving the problem]

[0006] The inventors of the present application have studied the length of the light source in the sub-scanning direction required to sufficiently cure the first ink discharged from the first nozzle of the first nozzle row and the second ink discharged from the second nozzle of the second nozzle row. As shown in FIG. 4, the length of the light source 43 at the portion located on one side (here, rearward) of the first nozzle row 31 in the sub-scanning direction X is length A, the length of the portion aligned with the first nozzle row 31 and the second nozzle row 32 in the main scanning direction Y is length B, and the length of the portion located on the other side (here, forward) of the second nozzle row 32 in the sub-scanning direction X is length C. The inventors have studied making the length A and the length C longer than the length B. As a result, the first ink and the second ink can be sufficiently cured, but the inventors faced the problem that the length T of the light source 43 in the sub-scanning direction X becomes very long, and the light source 43 becomes large. Therefore, the inventors have studied making the length A and the length C the same and making the length A shorter than the length B. With this configuration, the length T of the light source 43 in the sub-scanning direction X can be shortened. However, it was found that when the amount of light required to cure the first ink and the amount of light required to cure the second ink differ, making length A the same as length C may result in excessive light being irradiated onto one of the first ink and the second ink, and insufficient light being irradiated onto the other ink in the amount required for curing. Therefore, it was found that the light source can be made smaller by appropriately defining the relationship between length A and length C.

[0007] The inkjet printer of the present invention comprises a mounting table on which a recording medium is placed, a carriage disposed above the mounting table and movable in a main scanning direction, a moving device capable of moving one of the mounting table and the carriage relatively from one side to the other and from the other side to the one side in a sub-scanning direction intersecting the main scanning direction, a first nozzle row mounted on the carriage and having a plurality of first nozzles aligned in the sub-scanning direction and capable of ejecting toward the recording medium a first ink that is photocurable and requires a first amount of light to harden the ink, a second nozzle row mounted on the carriage and having a plurality of second nozzles aligned in the sub-scanning direction and capable of ejecting toward the recording medium a second ink that is photocurable and requires a second amount of light to harden the ink, the second amount of light being greater than the first amount of light, and a light irradiation device mounted 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. At least a portion of the first nozzles in the first nozzle row that eject the first ink are biased to one side of the sub-scanning direction relative to the second nozzles in the second nozzle row that eject the second ink, and when the length in the sub-scanning direction of a portion of the light source that is located on one side of the first nozzle row in the sub-scanning direction is length A, the lengths in the sub-scanning direction of portions that are aligned in the main scanning direction with the first nozzle row and the second nozzle row are length B, and the length in the sub-scanning direction of a portion that is located on the other side of the second nozzle row in the sub-scanning direction is length C, the length C is longer than the length A and the length C is the same as or shorter than the length B.

[0008] According to the inkjet printer of the present invention, since the length C is the same as or shorter than the length B, and the length A is shorter than the length C, the length of the light source in the sub-scanning direction can be made relatively short. This makes it possible to prevent the light source from becoming large. When printing is performed by moving the mounting table (i.e., the recording medium) from one side to the other in the sub-scanning direction, the second ink, which is less likely to harden than the first ink, is discharged later. However, by appropriately setting the length C to be the same as or shorter than the length B, the second ink can be sufficiently hardened. Also, when printing is performed by moving the mounting table (i.e., the recording medium) from the other side to one side in the sub-scanning direction, the first ink is discharged later. However, since the first ink is easier to harden than the second ink, the first ink can be sufficiently hardened even if the length A is set shorter than the length C. Effect of the Invention

[0009] According to the present invention, it is possible to provide an inkjet printer that can prevent the light source from becoming large. [Brief description of the drawings]

[0010] [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] 10 is a flow chart showing a procedure for forming an undercoat layer, a first ink layer, and a second ink layer in this order. [Figure 7] 1 is an example of a printed output. [Figure 8]10 is a flow chart showing a procedure for forming an undercoat layer, a second ink layer, and a first ink layer in this order. [Figure 9] 1 is an example of a printed output. [Figure 10] 10 is a flow chart showing a procedure for forming a first ink layer, a second ink layer and a surface layer in this order. [Figure 11] 1 is an example of a printed output. [Figure 12] 10 is a flow chart showing a procedure for forming a second ink layer, a first ink layer and a surface layer in this order. [Figure 13] 1 is an example of a printed output. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] FIG. 1 is a perspective view of a printer 10 according to this 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. Further, the forward direction X1 indicates the direction from the upstream side to the downstream side in the sub-scanning direction X (here, the direction from back to front), and the return direction X2 indicates the direction from the downstream side to the upstream side 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 the installation mode of the printer 10, nor limit the present invention.

[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 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.

[0014] 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.

[0015] 1, a window 23A is provided in the front and upper parts of the front cover 23. The window 23A is formed, for example, from 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.

[0016] 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.

[0017] Next, the internal configuration of the printer 10 will be described. 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, which will be described later, 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.

[0018] 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). As shown in FIG. 3, 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 a control device 70 (described later) 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.

[0019] 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.

[0020] 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. The ink head 30 and the ultraviolet irradiation device 40 are mounted on the carriage 20. 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 the control device 70. As the carriage 20 moves in the main scanning direction Y, the ink head 30 and the ultraviolet ray irradiation device 40 mounted on the carriage 20 also move in the main scanning direction Y.

[0021] 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. 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.

[0022] As shown in FIG. 4, the ink head 30 includes a first ink head 30A and a second ink head 30B. The first ink head 30A and the second ink head 30B are formed to have the same shape and the same size. The first ink head 30A and the second ink head 30B are formed to have 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 30A and the second ink head 30B are arranged side by side in the main scanning direction Y. The first ink head 30A is arranged to the right of the second ink head 30B. The first ink head 30A and the second ink head 30B are arranged at positions shifted from each other in the sub-scanning direction X. A part of the first ink head 30A is biased in the sub-scanning direction X with respect to the second ink head 30B. Here, the first ink head 30A is arranged upstream (here, rearward) of the second ink head 30B in the sub-scanning direction X. The first ink head 30A and the second ink head 30B are arranged in a so-called staggered arrangement. The first ink head 30A and the second ink head 30B are mounted on the carriage 20. That is, a first nozzle row 31, a second nozzle row 32, a third nozzle row 33, and a fourth nozzle row 34, which will be described later, are mounted on the carriage 20.

[0023] As shown in FIG. 4, the first ink head 30A includes a first nozzle row 31 in which a plurality of first nozzles 31A capable of ejecting a first ink toward the recording medium 5 are arranged in the sub-scanning direction X, and a first nozzle surface 30AS in which the first nozzles 31A are formed. Here, the first ink head 30A includes four first nozzle rows 31. The second ink head 30B includes a second nozzle row 32 in which a plurality of second nozzles 32A capable of ejecting a second ink toward the recording medium 5 are arranged in the sub-scanning direction X, a third nozzle row 33 in which a plurality of third nozzles 33A capable of ejecting a third ink toward the recording medium 5 are arranged in the sub-scanning direction X, a fourth nozzle row 34 in which a plurality of fourth nozzles 34A capable of ejecting a fourth ink toward the recording medium 5 are arranged in the sub-scanning direction X, and a second nozzle surface 30BS in which the second nozzles 32A, the third nozzles 33A, and the fourth nozzles 34A are formed. Here, the second ink head 30B includes two second nozzle rows 32, one third nozzle row 33, and one fourth nozzle row 34. At least some of the first nozzles 31A in the first nozzle row 31 that eject the first ink are biased to one side (here, rearward) in the sub-scanning direction X relative to the second nozzles 32A in the second nozzle row 32 that eject the second ink. In this embodiment, all the first nozzles 31A are located rearward of the second nozzles 32A. That is, the first nozzles 31A and the second nozzles 32A do not overlap with each other in the sub-scanning direction X. The second nozzles 32A, the third nozzles 33A, and the fourth nozzles 34A are arranged at the same positions in the sub-scanning direction X. In this embodiment, the number of first nozzles 31A in the first nozzle row 31 is the same as the number of second nozzles 32A in the second nozzle row 32, the number of third nozzles 33A in the third nozzle row 33, and the number of fourth nozzles 34A in the fourth nozzle row 34. In addition, the nozzle pitches (the distance between adjacent nozzles) of the first nozzle row 31 to the fourth nozzle row 34 are all the same. In this embodiment, two ink heads 30 are provided, but the number of ink heads 30 is not limited to two. Also, the ink head 30 has four nozzle rows, but the number of nozzle rows is not limited to four. Also, in Fig. 4, the first nozzle 31A, the second nozzle 32A, the third nozzle 33A, and the fourth nozzle 34A are represented by straight lines.

[0024] The first ink is an ink used for forming an image. The first ink has photocuring properties. That is, the first ink is a photocurable ink that has a property of being cured when irradiated with light (e.g., ultraviolet light). The first ink is cured to form a first ink layer (i.e., a printed layer). 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. The second ink is an ink used for forming a base before forming an image. The second ink is a photocurable ink that has photocuring properties. The second ink is cured to form a second ink layer (i.e., a white layer). The second ink is a white ink. The third ink is an ink used for forming a base before forming an image. The third ink is a photocurable ink that has photocuring properties. The third ink is cured to form a base layer. The third ink is, for example, a primer ink. The primer ink has adhesive properties. The fourth ink is an ink used for surface finishing after image formation. The fourth ink is a photocurable ink having photocurability. A surface layer is formed by curing the fourth ink. The fourth ink is, for example, a gloss ink. Here, if the amount of light required to cure the first ink is the first light amount, and the amount of light required to cure the second ink is the second light amount, the second light amount is greater than the first light amount. That is, the second ink has a property of being less likely to cure than the first ink. In addition, if the amount of light required to cure the third ink is the third light amount, and the amount of light required to cure the fourth ink is the fourth light amount, the third light amount and the fourth light amount are less than the first light amount. That is, the third ink and the fourth ink have a property of being more easily cured than the first ink.

[0025] As shown in FIG. 2, the printer 10 includes one ultraviolet ray irradiation device 40. The ultraviolet ray irradiation device 40 is mounted on the carriage 20. The ultraviolet ray irradiation device 40 is disposed above the table 35. As shown in FIG. 4, the ultraviolet ray irradiation device 40 is disposed to the right of the ink head 30. The ultraviolet ray irradiation device 40 may be disposed to the left of the ink head 30. The ultraviolet ray irradiation device 40 irradiates light (typically ultraviolet rays). The ultraviolet ray irradiation device 40 is configured to be able to irradiate light (here, ultraviolet rays) to an area (i.e., a printing area) on the recording medium 5 where the first ink, the second ink, the third ink, and the fourth ink are ejected. The ultraviolet ray irradiation device 40 is configured to be able to irradiate light toward the first ink, the second ink, the third ink, and the fourth ink ejected on the recording medium 5. The ultraviolet ray irradiation device 40 includes a light source 43 that irradiates light. In this embodiment, the ultraviolet ray irradiation device 40 includes a plurality of light sources 43 arranged in the sub-scanning direction X. The light source 43 irradiates light (ultraviolet light in this case) onto the areas where the first ink, the second ink, the third ink, and the fourth ink are ejected onto the recording medium 5. Although the light source 43 is illustrated as a straight line in FIG. 4, in reality, a large number of light sources 43 (for example, 30 pieces) are provided. The light source 43 is, for example, an LED. The ultraviolet irradiation device 40 is an example of a light irradiation device.

[0026] 4, in the ultraviolet irradiation device 40, a plurality of light sources 43 are arranged in a row to form a light source array 44. The length T in the sub-scanning direction X of the light source array 44 is longer than the length TN from the first nozzle 31A located at the rearmost position of the first nozzle array 31 to the second nozzle 32A located at the frontmost position of the second nozzle array 32. The light source array 44 includes a first light source array 44A in which some of the light sources 43 are arranged in the sub-scanning direction X, a second light source array 44B located downstream (in this case, forward) of the first light source array 44A in the sub-scanning direction and in which some of the light sources 43 are arranged in the sub-scanning direction X, a third light source array 44C located downstream of the second light source array 44B in the sub-scanning direction and in which some of the light sources 43 are arranged in the sub-scanning direction X, and a fourth light source array 44D located downstream of the third light source array 44C in the sub-scanning direction and in which some of the light sources 43 are arranged in the sub-scanning direction X. In this embodiment, the first light source row 44A is located upstream (rearward here) of the first nozzle row 31 in the sub-scanning direction X. The second light source row 44B is aligned with the first nozzle row 31 in the main scanning direction Y. The second light source row 44B overlaps with the first nozzle row 31 in the sub-scanning direction X. The third light source row 44C is aligned with the second nozzle row 32 in the main scanning direction Y. The third light source row 44C overlaps with the second nozzle row 32 in the sub-scanning direction X. The fourth light source row 44D is located downstream of the second nozzle row 32 in the sub-scanning direction X. That is, the first nozzles 31A to the fourth nozzles 34A are not arranged to the side (left here) of the first light source row 44A and the fourth light source row 44D in the main scanning direction Y. The first light source row 44A is an example of a portion of the light source 43 located on one side of the first nozzle row 31 in the sub-scanning direction X, the second light source row 44B is an example of a portion of the light source 43 aligned with the first nozzle row 31 in the main scanning direction Y, the third light source row 44C is an example of a portion of the light source 43 aligned with the second nozzle row 32 in the main scanning direction Y, and the fourth light source row 44D is an example of a portion of the light source 43 located on the other side of the second nozzle row 32 in the sub-scanning direction X. When the length of the first light source row 44A in the sub-scanning direction X is length A, the lengths of the second light source row 44B and the third light source row 44C in the sub-scanning direction X are length B, and the length of the fourth light source row 44D in the sub-scanning direction X is length D, the length C is longer than the length A (length C>length A) and the length C is the same as or shorter than the length B (length C≦length B).For example, the length C is between 1.1A and 2.0A, and the length B is between 1.0C and 5.0C.

[0027] 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.

[0028] 5, the control device 70 is communicatively connected to the operation panel 25, the carriage moving mechanism 21, the first ink head 30A, the second ink head 30B, 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 30A, the second ink head 30B, the ultraviolet irradiation device 40, the first motor 39A, and the second motor 39B.

[0029] The control device 70 controls the amount and timing of the first ink discharged from the first nozzle 31A of the first ink head 30A. The control device 70 controls the amount and timing of the second ink, third ink, and fourth ink discharged from the second nozzle 32A, third nozzle 33A, and fourth nozzle 34A of the second ink head 30B, respectively. 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.

[0030] As shown in FIG. 5, the control device 70 includes a first ink layer pre-forming unit 71, a first ink layer post-forming unit 73, a base layer forming unit 75, and a surface layer forming unit 77. 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 to a ROM mounted on a board inside the printer 10, or written from a PC to an FPGA mounted on a board inside the printer 10 using a dedicated writing tool. For example, the program is downloaded to the 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.

[0031] The first ink layer forming section 71 ejects the first ink from the first nozzle 31A onto the recording medium 5 to form a first ink layer 81 (see FIG. 7) during the first movement of moving the recording medium 5 from one side to the other side (here, from rear to front) in the sub-scanning direction X relative to the carriage 20 (i.e., when moving the recording medium 5 in the forward direction X1), and ejects the second ink from the second nozzle 32A onto the first ink layer 81 to form a second ink layer 82 (see FIG. 7) on the first ink layer 81. The first ink layer forming section 71 irradiates the first ink ejected onto the recording medium 5 with light from the light source 43 to form the first ink layer 81, and irradiates the second ink ejected onto the first ink layer 81 with light from the light source 43 to form the second ink layer 82. Usually, the first ink layer 81 and the second ink layer 82 are formed during one first movement. Here, the second light amount required to cure the second ink is greater than the first light amount required to cure the first ink, but the length C of the fourth light source row 44D in the sub-scanning direction X is sufficiently longer than the length A of the first light source row 44A in the sub-scanning direction X, so that the second ink discharged later can be more reliably cured to form the second ink layer 82. Note that, if a base layer 83 (see FIG. 7 ) described later is formed on the recording medium 5 before the first ink layer 81 is formed, the first ink layer forming unit 71 discharges the first ink from the first nozzle 31A onto the base layer 83 to form the first ink layer 81 on the base layer 83. The first ink layer forming unit 71 controls the carriage moving mechanism 21, the first ink head 30A and the second ink head 30B, the light source 43 of the ultraviolet ray irradiation device 40, and the first table moving mechanism 36.

[0032] The first ink layer post-forming unit 73 ejects the second ink from the second nozzle 32A onto the recording medium 5 during a second movement in which the recording medium 5 is moved from the other side to one side (here, from front to rear) in the sub-scanning direction X relative to the carriage 20 (i.e., when the recording medium 5 is moved in the return direction X2), and ejects the first ink from the first nozzle 31A onto the second ink layer 82 to form a first ink layer 81 (see FIG. 9) on the second ink layer 82. The first ink layer post-forming unit 73 irradiates the second ink ejected onto the recording medium 5 with light from the light source 43 to form the second ink layer 82, and irradiates the first ink ejected onto the second ink layer 82 with light from the light source 43 to form the first ink layer 81. Usually, the second ink layer 82 and the first ink layer 81 are formed during one second movement. Here, the second amount of light required to cure the second ink is greater than the first amount of light required to cure the first ink, but since the second ink layer 82 is formed first, it is reliably cured during the second movement. Also, the length A of the first light source row 44A in the sub-scanning direction X is shorter than the length C of the fourth light source row 44D in the sub-scanning direction X, but the first amount of light required to cure the first ink is less than the second amount of light required to cure the second ink, so that the first ink discharged later can be more reliably cured to form the first ink layer 81. Note that, in the case where a base layer 83 (see FIG. 9 ) described later is formed on the recording medium 5 before the second ink layer 82 is formed, the first ink layer post-forming unit 73 discharges the second ink from the second nozzle 32A onto the base layer 83 to form the second ink layer 82 on the base layer 83. The first ink layer post-forming unit 73 controls the carriage moving mechanism 21, the first ink head 30A and the second ink head 30B, the light source 43 of the ultraviolet irradiating device 40, and the first table moving mechanism .

[0033] During a first movement of the recording medium 5 from one side to the other side (here, from rear to front) in the sub-scanning direction X relative to the carriage 20 (i.e., when the recording medium 5 is moved in the forward direction X1), the base layer forming unit 75 ejects the third ink from the third nozzle 33A onto the recording medium 5 during a second movement of the recording medium 5 from the other side to one side (here, from front to the other) in the sub-scanning direction X relative to the carriage 20 (i.e., when the recording medium 5 is moved in the return direction X2), to form a base layer 83 (see FIG. 7). That is, when forming the base layer 83, the first ink layer 81, and the second ink layer 82 in this order, the base layer forming unit 75 forms the base layer 83 in the return direction X2, and then the first ink layer pre-forming unit 71 forms the first ink layer 81 and the second ink layer 82 in the forward direction X1. Furthermore, the base layer forming unit 75 ejects the third ink from the third nozzle 33A onto the recording medium 5 during the first movement to form the base layer 83, before forming the first ink layer 81 on the second ink layer 82 during the second movement. That is, when forming the base layer 83, the second ink layer 82, and the first ink layer 81 in this order, the base layer forming unit 75 forms the base layer 83 in the forward direction X1, and then the first ink layer post-forming unit 73 forms the second ink layer 82 and the first ink layer 81 in the return direction X2.

[0034] During a first movement of the recording medium 5 from one side to the other side (here, from rear to front) in the sub-scanning direction X relative to the carriage 20 (i.e., when the recording medium 5 is moved in the forward direction X1), the surface layer forming unit 77 forms a surface layer 84 (see FIG. 11) by ejecting a fourth ink from the fourth nozzle 34A onto the second ink layer 82 during a second movement of the recording medium 5 from the other side to one side (here, from front to the other) in the sub-scanning direction X relative to the carriage 20 (i.e., when the recording medium 5 is moved in the return direction X2). That is, when the first ink layer 81, the second ink layer 82, and the surface layer 84 are formed in this order, the first ink layer forming unit 71 forms the first ink layer 81 and the second ink layer 82 in the forward direction X1, and then the surface layer forming unit 77 forms the surface layer 84 in the return direction X2. Furthermore, after the first ink layer 81 is formed on the second ink layer 82 during the second movement, the surface layer forming unit 77 ejects the fourth ink from the fourth nozzle 34A onto the first ink layer 81 during the first movement to form a surface layer 84 (see FIG. 13). That is, when forming the second ink layer 82, the first ink layer 81, and the surface layer 84 in this order, the first-ink layer post-forming unit 73 forms the second ink layer 82 and the first ink layer 81 in the return direction X2, and then the surface layer forming unit 77 forms the surface layer 84 in the forward direction X1.

[0035] Fig. 6 is a flow chart showing the procedure for obtaining a print result 90A by forming, in order, the undercoat layer 83, the first ink layer 81, and the second ink layer 82. Fig. 7 is a cross-sectional view of the print result 90A.

[0036] First, in step S10, the base layer forming unit 75 forms a base layer 83 (see FIG. 7) on the recording medium 5 while moving the recording medium 5 in the return direction X2. Then, in step S20, the first ink layer forming unit 71 forms a first ink layer 81 (see FIG. 7) on the base layer 83 while moving the recording medium 5 in the forward direction X1. Then, in step S30, the first ink layer forming unit 71 forms a second ink layer 82 (see FIG. 7) on the first ink layer 81 while moving the recording medium 5 in the forward direction X1. Note that steps S20 and S30 are performed simultaneously. That is, the first ink layer 81 and the second ink layer 82 are formed while the recording medium 5 moves once in the forward direction X1.

[0037] Fig. 8 is a flow chart showing the procedure for obtaining a print result 90B by forming, in this order, the undercoat layer 83, the second ink layer 82, and the first ink layer 81. Fig. 9 is a cross-sectional view of the print result 90B.

[0038] First, in step S110, the base layer forming unit 75 forms a base layer 83 (see FIG. 9) on the recording medium 5 while moving the recording medium 5 in the forward direction X1. Then, in step S120, the first ink layer forming unit 71 forms a second ink layer 82 (see FIG. 9) on the base layer 83 while moving the recording medium 5 in the return direction X2. Then, in step S130, the first ink layer forming unit 71 forms a first ink layer 81 (see FIG. 9) on the second ink layer 82 while moving the recording medium 5 in the return direction X2. Note that steps S120 and S130 are performed simultaneously. That is, the second ink layer 82 and the first ink layer 81 are formed while the recording medium 5 moves once in the return direction X2.

[0039] Fig. 10 is a flow chart showing the procedure for obtaining a print result 90C by forming the first ink layer 81, the second ink layer 82, and the surface layer 84 in this order. Fig. 11 is a cross-sectional view of the print result 90C.

[0040] First, in step S210, the first ink layer forming unit 71 forms a first ink layer 81 (see FIG. 11) on the recording medium 5 while moving the recording medium 5 in the forward direction X1. Then, in step S220, the first ink layer forming unit 71 forms a second ink layer 82 (see FIG. 11) on the first ink layer 81 while moving the recording medium 5 in the forward direction X1. Note that steps S210 and S220 are performed simultaneously. That is, the first ink layer 81 and the second ink layer 82 are formed while the recording medium 5 moves once in the forward direction X1. Then, in step S230, the surface layer forming unit 77 forms a surface layer 84 (see FIG. 11) on the second ink layer 82 while moving the recording medium 5 in the return direction X2.

[0041] Fig. 12 is a flow chart showing the procedure for obtaining a print result 90D by forming the second ink layer 82, the first ink layer 81, and the surface layer 84 in this order. Fig. 13 is a cross-sectional view of the print result 90D.

[0042] First, in step S310, the first ink layer forming unit 71 forms a second ink layer 82 (see FIG. 13) on the recording medium 5 while moving the recording medium 5 in the return direction X2. Then, in step S320, the first ink layer forming unit 71 forms a first ink layer 81 (see FIG. 13) on the second ink layer 82 while moving the recording medium 5 in the return direction X2. Note that steps S310 and S320 are performed simultaneously. That is, the second ink layer 82 and the first ink layer 81 are formed while the recording medium 5 moves once in the return direction X2. Then, in step S330, the surface layer forming unit 77 forms a surface layer 84 (see FIG. 13) on the first ink layer 81 while moving the recording medium 5 in the forward direction X1.

[0043] As described above, according to the printer 10 of this embodiment, the length C in the sub-scanning direction X of the fourth light source row 44D is equal to or shorter than the length B in the sub-scanning direction X of the second light source row 44B and the third light source row 44C, and the length A in the sub-scanning direction X of the first light source row 44A is shorter than the length C, so that the length T in the sub-scanning direction X of the light source 43 can be made relatively short. This makes it possible to prevent the light source 43 from becoming large. Note that when printing is performed by moving the table 35 (i.e., the recording medium 5) from one side to the other side in the sub-scanning direction X (here, from rear to front), the second ink, which is less likely to harden than the first ink, is ejected later, but the second ink can be sufficiently hardened by appropriately setting the length C to be equal to or shorter than the length B. Furthermore, when printing is performed by moving the table 35 (i.e., the recording medium 5) from the other side to one side (here, from front to rear) in the sub-scanning direction X, the first ink is ejected later. However, since the first ink is easier to harden than the second ink, the first ink can be sufficiently hardened even if the length A is set shorter than the length C.

[0044] The printer 10 of this embodiment is equipped with a first ink head 30A mounted on the carriage 20 and including a first nozzle row 31, and a second ink head 30B mounted on the carriage 20, aligned with the first ink head 30A in the main scanning direction Y, and including a second nozzle row 32, with at least a portion of the first ink head 30A biased in the sub-scanning direction X with respect to the second ink head 30B. With this configuration, overprinting of the first ink and the second ink can be performed using a larger number of first nozzles 31A and second nozzles 32A.

[0045] In the printer 10 of this embodiment, the first ink is an image forming ink, and the second ink is a white ink. Since the image forming ink has a property of being more easily cured than the white ink, the length A can be set shorter than the length C, and the light source 43 can be made smaller.

[0046] According to the printer 10 of this embodiment, the control device 70 has a first ink layer forming unit 71 that ejects a first ink from the first nozzle 31A onto the recording medium 5 to form a first ink layer 81, and ejects a second ink from the second nozzle 32A onto the first ink layer 81, during a first movement in which the recording medium 5 moves from one side to the other side (here, from rear to front) in the sub-scanning direction relative to the carriage 20. With this configuration, the second ink layer 82 can be cured more reliably by appropriately setting the length C.

[0047] According to the printer 10 of this embodiment, the control device 70 has a base layer forming section 75 that ejects the third ink from the third nozzle 33A onto the recording medium 5 to form a base layer 83 during a second movement in which the recording medium 5 is moved from the other side to one side (here, from front to rear) in the sub-scanning direction X relative to the carriage 20 before forming the second ink layer 82 on the first ink layer 81 during the first movement, and the first ink layer forming section 71 ejects the first ink from the first nozzle 31A onto the base layer 83 to form the first ink layer 81 on the base layer 83. With this configuration, immediately after forming the base layer 83 during the second movement, the first ink layer 81 can be formed on the base layer 83 during the first movement and the second ink layer 82 can be formed on the first ink layer 81. This makes it possible to suppress adhesion of dust and the like to the base layer 83.

[0048] According to the printer 10 of this embodiment, the control device 70 has a surface layer forming unit 77 that, after the second ink layer 82 is formed on the first ink layer 81 during the first movement, ejects a fourth ink from the fourth nozzle 34A onto the second ink layer 82 to form a surface layer 84 during the second movement in which the recording medium 5 is moved from the other side to one side (here, from front to rear) in the sub-scanning direction X relative to the carriage 20. With this configuration, immediately after the second ink layer 82 is formed on the first ink layer 81 during the first movement, the surface layer 84 can be formed on the second ink layer 82 during the second movement.

[0049] According to the printer 10 of this embodiment, the control device 70 has a first ink layer post-forming unit 73 that ejects the second ink from the second nozzles 32A onto the recording medium 5 to form a second ink layer 82, and ejects the first ink from the first nozzles 31A onto the second ink layer 82 to form a first ink layer 81 on the second ink layer 82, during a second movement in which the recording medium 5 moves from the other side to one side (here, from front to rear) in the sub-scanning direction X relative to the carriage 20. With this configuration, the first ink layer 81 can be cured more reliably by appropriately setting the length A.

[0050] According to the printer 10 of this embodiment, the control device 70 has a base layer forming section 75 that ejects the third ink from the third nozzle 33A onto the recording medium 5 to form a base layer 83 during the first movement in which the recording medium 5 is moved from one side to the other side in the sub-scanning direction X (here, from rear to front) relative to the carriage 20 before forming the first ink layer 81 on the second ink layer 82 during the second movement, and the first ink layer post-forming section 73 ejects the second ink from the second nozzle 32A onto the base layer 83 to form the second ink layer 82 on the base layer 83. With this configuration, immediately after forming the base layer 83 during the first movement, the second ink layer 82 can be formed on the base layer 83 and the first ink layer 81 can be formed on the second ink layer 82 during the second movement. This makes it possible to suppress adhesion of dust and the like to the base layer 83.

[0051] According to the printer 10 of this embodiment, the control device 70 has a surface layer forming unit 77 that ejects a fourth ink from the fourth nozzle 34A onto the first ink layer 81 to form a surface layer 84 during a first movement in which the recording medium 5 moves from one side to the other side (here, from rear to front) in the sub-scanning direction X relative to the carriage 20 after the first ink layer 81 is formed on the second ink layer 82 during the second movement. With this configuration, the surface layer 84 can be formed on the first ink layer 81 during the first movement immediately after the first ink layer 81 is formed on the second ink layer 82 during the second movement.

[0052] 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.

[0053] In the above-described embodiment, the first nozzles 31A and the second nozzles 32A are arranged to be shifted in the sub-scanning direction X, but a part of the first nozzles 31A and a part of the second nozzles 32A may be arranged to overlap in the sub-scanning direction X. When a part of the first nozzles 31A and a part of the second nozzles 32A are arranged to overlap in the sub-scanning direction X, it is sufficient that the second nozzles 32A are arranged to be shifted from the nozzle pitch of the first nozzles 31A.

[0054] In the above-described embodiment, the first nozzles 31A and the second nozzles 32A are arranged to be shifted from each other in the sub-scanning direction X, but all the first nozzles 31A and all the second nozzles 32A may be arranged to overlap each other in the sub-scanning direction X. In this case, at least some of the first nozzles 31A that actually eject the first ink are biased to one side (here, rearward) in the sub-scanning direction X with respect to the second nozzles 32A that actually eject the second ink. That is, the second ink is not ejected from the second nozzles 32A that overlap with the first nozzles 31A that actually eject the first ink in the sub-scanning direction X, and the first ink is not ejected from the first nozzles 31A that overlap with the second nozzles 32A that actually eject the second ink in the sub-scanning direction X.

[0055] In the above-described embodiment, the printer 10 includes one ultraviolet irradiation device 40, but may include two ultraviolet irradiation devices 40. That is, an ultraviolet irradiation device 40 may be provided on each of the right and left sides of the ink head 30.

[0056] In the above embodiment, the first ink head 30A and the second ink head 30B are provided separately, but they may be integrated. That is, the first nozzle row 31, the second nozzle row 32, the third nozzle row 33, and the fourth nozzle row 34 may be provided in one ink head 30.

[0057] 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. [Explanation of symbols]

[0058] 10 Printer (inkjet printer) 20 Carriage 30 Ink head 30A 1st ink head 30B 2nd ink head 31 1st nozzle row 31A No. 1 nozzle 32 Second nozzle row 32A No. 2 nozzle 35 Table (Placement stand) 36 First table moving mechanism (moving device) 40 Ultraviolet irradiation device (light irradiation device) 43 Light source 70 Control device 71 First ink layer forming section 73 First ink layer post-forming section 81 First ink layer 82 2nd ink layer

Claims

1. a mounting table on which a recording medium is mounted; a carriage disposed above the mounting table and movable in a main scanning direction; a moving device capable of relatively moving one of the mounting table and the carriage with respect to the other from one side to the other and from the other side to the one side in a sub-scanning direction intersecting the main scanning direction; a first nozzle row that is mounted on the carriage and has a plurality of first nozzles arranged in the sub-scanning direction and that can eject a first ink toward the recording medium, the first ink having photocurability and requiring a first amount of light for curing; a second nozzle row in which a plurality of second nozzles are arranged in the sub-scanning direction and which is mounted on the carriage and capable of ejecting a second ink, which has photocurability and requires a second light amount that is greater than the first light amount, toward the recording medium; a light irradiation device that is mounted 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, at least a portion of the first nozzles in the first nozzle row that eject the first ink are biased toward one side in the sub-scanning direction with respect to the second nozzles in the second nozzle row that eject the second ink, an inkjet printer in which, when a length in the sub-scanning direction of a portion of the light source located on one side of the first nozzle row in the sub-scanning direction is defined as length A, lengths in the sub-scanning direction of portions aligned in the main scanning direction with the first nozzle row and the second nozzle row are each defined as length B, and a length in the sub-scanning direction of a portion located on the other side of the second nozzle row in the sub-scanning direction is defined as length C, length C is longer than length A and length C is the same as or shorter than length B.

2. a first ink head mounted on the carriage and including the first nozzle row; a second ink head that is mounted on the carriage, that is aligned with the first ink head in the main scanning direction, and that includes the second nozzle row; 2. The inkjet printer according to claim 1, wherein at least a portion of the first ink head is offset in the sub-scanning direction with respect to the second ink head.

3. the first ink is an image forming ink, 3. The inkjet printer according to claim 1, wherein the second ink is a white ink.

4. A control device is further provided.

4. The inkjet printer according to claim 1, wherein the control device has a first ink layer forming unit that, during a first movement that moves the recording medium from one side to the other side in the sub-scanning direction relative to the carriage, ejects the first ink from the first nozzle onto the recording medium to form a first ink layer, and ejects the second ink from the second nozzle onto the first ink layer to form a second ink layer on the first ink layer.

5. a third nozzle row, which is mounted on the carriage and has a plurality of third nozzles arranged in the sub-scanning direction and capable of ejecting a third ink, which is photocurable and is used for forming a base before forming an image, toward the recording medium; the light source is configured to irradiate light onto an area of ​​the recording medium onto which the third ink is ejected; the control device has an undercoat layer forming unit that, during a second movement in which the recording medium is moved from the other side to one side in the sub-scanning direction relative to the carriage, forms an undercoat layer before the second ink layer is formed on the first ink layer during the first movement, by ejecting the third ink from the third nozzle onto the recording medium, The inkjet printer according to claim 4 , wherein the first-ink layer pre-forming unit forms the first ink layer on the base layer by ejecting the first ink from the first nozzle onto the base layer.

6. a fourth nozzle row that is mounted on the carriage and has a plurality of fourth nozzles aligned in the sub-scanning direction and that can eject a fourth ink that is photocurable and is used for surface finishing after image formation toward the recording medium; the light source is configured to irradiate light onto an area of ​​the recording medium onto which the fourth ink is ejected; 5. The inkjet printer according to claim 4, wherein the control device has a surface layer forming unit that, after the second ink layer is formed on the first ink layer during the first movement, ejects the fourth ink from the fourth nozzle onto the second ink layer during a second movement that moves the recording medium from the other side to one side in the sub-scanning direction relative to the carriage to form a surface layer.

7. 5. The inkjet printer according to claim 4, wherein the control device has a first ink layer post-forming unit that ejects the second ink from the second nozzle onto the recording medium to form the second ink layer during a second movement in which the recording medium is moved from the other side to one side in the sub-scanning direction relative to the carriage, and that ejects the first ink from the first nozzle onto the second ink layer to form the first ink layer on the second ink layer.

8. a third nozzle row, which is mounted on the carriage and has a plurality of third nozzles arranged in the sub-scanning direction and capable of ejecting a third ink, which is photocurable and is used for forming a base before forming an image, toward the recording medium; the light source is configured to irradiate light onto an area of ​​the recording medium onto which the third ink is ejected; the control device has an undercoat layer forming unit that, during a first movement in which the recording medium is moved from one side to the other side in the sub-scanning direction relative to the carriage, forms an undercoat layer before the first ink layer is formed on the second ink layer during the second movement, by ejecting the third ink from the third nozzle onto the recording medium, The inkjet printer according to claim 7 , wherein the first-ink layer post-forming unit ejects the second ink from the second nozzle onto the base layer to form the second ink layer on the base layer.

9. a fourth nozzle row that is mounted on the carriage and has a plurality of fourth nozzles aligned in the sub-scanning direction and that can eject a fourth ink that is photocurable and is used for surface finishing after image formation toward the recording medium; the light source is configured to irradiate light onto an area of ​​the recording medium onto which the fourth ink is ejected; 8. The inkjet printer according to claim 7, wherein the control device has a surface layer forming unit that, after the first ink layer is formed on the second ink layer during the second movement, ejects the fourth ink from the fourth nozzle onto the first ink layer during a first movement that moves the recording medium from one side to the other side in the sub-scanning direction relative to the carriage to form a surface layer.

Images