Printer and printing method

Abstract

The present invention achieves printing of a glossy tone using a color ink while making it difficult for the printing quality to deteriorate. A control device 60 of a printer 10 comprises: a first discharge control unit 71 that causes a color ink to be discharged from an ink head 32 to form a first ink layer L1 on a printing object 5; a second discharge control unit 72 that causes the color ink to be discharged from the ink head 32 to form a second ink layer L2 on the first ink layer L1; and a post-processing control unit 73 that controls a post-processing device 35 for performing post-processing of the color ink discharged onto the printing object 5, which is supported by a support base 25. The post-processing control unit 73 controls the post-processing device 35 such that the surface of the first ink layer L1 becomes a matte tone, and controls the post-processing device 35 such that the surface of the second ink layer L2 becomes a glossy tone.

Description

Printer and Printing Method

[0001] The present invention relates to a printer and a printing method.

[0002] For example, Patent Document 1 discloses a printing apparatus including a color ink head that discharges color ink, a clear ink head that discharges clear ink, and an ultraviolet irradiation device that irradiates ultraviolet rays. In this printing apparatus, as printing modes, a gloss mode, a matte mode, and an edge gloss mode are prepared.

[0003] In the gloss mode, printing with a gloss finish is performed by smoothing the surface. In the matte mode, printing with a matte finish is performed by forming irregularities on the surface. The edge gloss mode is a mode corresponding to an intermediate between the gloss mode and the matte mode. Here, the time from when the ink lands on the substrate until ultraviolet rays are irradiated becomes longer in the order of the matte mode, the edge gloss mode, and the gloss mode.

[0004] At the time of printing, first, in the matte mode, an image layer is formed on the substrate using color ink. Next, in the edge gloss mode, a pattern layer is formed on the image layer using clear ink. Then, in the gloss mode, a protective layer is formed on the pattern layer using clear ink. As a result, printing with a gloss finish can be performed by the surface of the protective layer.

[0005] Japanese Unexamined Patent Application Publication No. 2018 - 111211

[0006] By the way, there is a demand to realize gloss printing using only color ink instead of performing gloss printing with clear ink as in the printing apparatus disclosed in Patent Document 1. Even when gloss printing is realized using only color ink, it is preferable that the print quality does not deteriorate.

[0007] The present invention has been made in view of such a point, and an object thereof is to provide a printer capable of realizing gloss printing using color ink and making it difficult for the print quality to deteriorate.

[0008] The printer according to the present invention comprises a support stand for supporting a workpiece, an ink head for ejecting color ink toward the workpiece supported on the support stand, a post-processing device for performing post-processing on the color ink ejected toward the workpiece supported on the support stand, and a control device. The control device comprises a first ejection control unit for ejecting color ink from the ink head to form a first ink layer on the workpiece supported on the support stand, a second ejection control unit for ejecting color ink from the ink head to form a second ink layer on the first ink layer, and a post-processing control unit for controlling the post-processing device. The post-processing control unit controls the post-processing device so that the surface of the first ink layer becomes matte, and controls the post-processing device so that the surface of the second ink layer becomes glossy.

[0009] According to the above printer, the first ink layer can be made matte, and the second ink layer can be made glossy. As a result, even when printing using only color inks, it is possible to achieve a glossy finish while minimizing the degradation of print quality.

[0010] According to the present invention, it is possible to provide a printer that can achieve glossy printing using color ink while minimizing the degradation of print quality.

[0011] Figure 1 is a perspective view showing a printer according to the first embodiment. Figure 2 is a front view showing a printer according to the first embodiment. Figure 3 is a block diagram of the printer according to the first embodiment. Figure 4 is a schematic diagram showing the configuration of the bottom surface of the ink head and light irradiation device. Figure 5 is a cross-sectional view showing a substrate on which the first ink layer and the second ink layer are formed. Figure 6 is a flowchart showing the basic procedure during printing. Figure 7 is a schematic plan view showing the state of the light irradiation device while the ink head is moving in the forward direction when irradiating the first ink layer with light. Figure 8 is a schematic plan view showing the state of the light irradiation device while the ink head is moving in the return direction when irradiating the first ink layer with light. Figure 9 is a schematic plan view showing the state of the light irradiation device when irradiating the second ink layer with light. Figure 10 is a table showing the relationship between the amount of first ink and the amount of second ink for low-absorption color ink and high-absorption color ink. Figure 11 is a graph showing the reflectance density according to the amount of second ink in the second ink layer for cyan ink, magenta ink, yellow ink, and black ink. Figure 12 is a graph showing the standard allocation table. Figure 13 is a graph showing the first low allocation table of the first allocation table. Figure 14 is a graph showing the first high allocation table of the first allocation table. Figure 15 is a graph showing the second low allocation table of the second allocation table. Figure 16 is a graph showing the second high allocation table of the second allocation table. Figure 17 is a schematic diagram showing the configuration of the bottom surface of the ink head and light irradiation device in a printer according to the second embodiment. Figure 18 is a schematic plan view showing the state of the light irradiation device while the ink head is moving in the forward direction in the second embodiment. Figure 19 is a schematic plan view showing the state of the light irradiation device while the ink head is moving in the return direction in the second embodiment. Figure 20 is a diagram showing the relationship between the first pass mask and the second pass mask used when ejecting low absorption color ink and the nozzle row. Figure 21 is a diagram showing the relationship between the first pass mask and the second pass mask used when ejecting high absorption color ink and the nozzle row.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Naturally, the embodiment described herein is not intended to particularly limit the present invention. Furthermore, the same reference numerals are used for members and parts that perform the same function, and redundant explanations are omitted or simplified as appropriate.

[0013] <First Embodiment> Figure 1 is a perspective view showing a printer 10 according to the first embodiment. Figure 2 is a front view showing the printer 10. Figure 3 is a block diagram of the printer 10. In the following description, when a user views the printer 10 from the front, the direction away from the printer 10 is referred to as the front, and the direction towards the printer 10 is referred to as the rear. Left, right, up, and down refer to the left, right, up, and down directions when the user views the printer 10 from the front. Also, the symbol Y in the drawings indicates the main scanning direction. Here, the main scanning direction Y is the left-right direction. The direction from one side (here, the right) to the other side (here, the left) of the main scanning direction Y is called the forward direction Y1. The direction from the other side to the first side of the main scanning direction Y is called the return direction Y2. The symbol X indicates the sub-scanning direction. The sub-scanning direction X intersects (here, orthogonal) with the main scanning direction Y in a plan view. The sub-scanning direction X is, for example, the front-back direction. The symbol Z indicates the height direction, in other words, the up and down direction. However, these directions are merely defined for the sake of explanation and do not limit the installation configuration of the printer 10 in any way, nor do they limit the present invention in any way.

[0014] As shown in Figure 2, the printer 10 prints on the substrate 5 by ejecting ink (specifically color ink) onto the substrate 5. The substrate 5 is, for example, recording paper. However, the substrate 5 is not limited to recording paper. For example, the substrate 5 may include relatively thick materials such as sheets made from resin materials such as PCV or polyester, metal plates, glass plates, or wooden boards. The substrate 5 may also be a three-dimensional object such as a smartphone case.

[0015] Printer 10 is an inkjet printer, a so-called inkjet printer. Printer 10 is a so-called flatbed type printer, configured such that the support base 25 (see Figure 2), described later, moves in the sub-scanning direction X, and the ink head 32 (see Figure 2), described later, moves in the main scanning direction Y. However, printer 10 may also be a so-called roll-to-roll type printer, in which only the print material 5 is moved in the sub-scanning direction X while the roll-shaped print material 5 is unfolded. Alternatively, printer 10 may also be a so-called gantry type printer, in which the ink head 32 is moved in both the main scanning direction Y and the sub-scanning direction X relative to the support base 25.

[0016] As shown in Figure 1, the printer 10 comprises a printer body 11 and a cover 12. The printer body 11 is, for example, rectangular and case-shaped. However, the shape of the printer body 11 is not particularly limited. The printer body 11 has an internal space. Printing takes place in this internal space. As shown in Figure 2, an opening 15 is formed at the front of the printer body 11.

[0017] The cover 12 is supported on the printer body 11 so that the opening 15 can be opened and closed. The cover 12 is configured to rotate around its rear end as an axis. As shown in Figure 1, windows 16 are provided on the front and top of the cover 12. The windows 16 are made of a transparent or translucent material, such as an acrylic plate. The user can see the internal space of the printer body 11 through the windows 16.

[0018] In this embodiment, as shown in Figure 1, the printer 10 is equipped with an operation panel 20. The operation panel 20 is provided on the printer body 11. Specifically, the operation panel 20 is provided on the upper right part of the printer body 11, but the position of the operation panel 20 relative to the printer body 11 is not particularly limited. The operation panel 20 has a display screen 21 that displays information related to the status of the printer 10, and operation keys 22. The user can display various information related to the status of the printer 10 on the display screen 21 by operating the operation keys 22, for example. In this embodiment, the operation keys 22 are composed of physical buttons, but they may also be implemented by a touch panel provided on the display screen 21, for example.

[0019] Next, the internal configuration of the printer 10 according to this embodiment will be described. As shown in Figure 2, the printer 10 is equipped with a support base 25. The support base 25 supports the object to be printed 5. Here, the object to be printed 5 is placed on the upper surface of the support base 25. Printing is performed on the object to be printed 5 on the support base 25. Here, color ink is ejected onto the object to be printed 5 supported by the support base 25. The upper surface of the support base 25 is a flat surface that extends in the main scanning direction Y and the sub-scanning direction X, and functions as a support surface for supporting the object to be printed 5.

[0020] As shown in Figure 2, the printer 10 comprises a guide rail 28, a carriage 30, an ink head 32, and a light irradiation device 35. The guide rail 28 is located in the internal space of the printer body 11 and is fixed to the printer body 11. The guide rail 28 is positioned above the support base 25. The guide rail 28 extends in the main scanning direction Y. The carriage 30 is slidably mounted on the guide rail 28. The carriage 30 is configured to be movable along the guide rail 28 in the main scanning direction Y.

[0021] The ink head 32 is positioned above the support base 25. Here, the ink head 32 is positioned above the workpiece 5 supported by the support base 25. The ink head 32 ejects color ink toward the workpiece 5 supported by the support base 25. The ink head 32 is mounted on the carriage 30. Here, the ink head 32 is supported on the carriage 30 with its bottom surface exposed downwards. The number of ink heads 32 is not particularly limited. In this embodiment, there is one ink head 32, but there may be multiple.

[0022] Figure 4 is a schematic diagram showing the configuration of the bottom surface of the ink head 32 and the light irradiation device 35. As shown in Figure 4, the ink head 32 has a nozzle row 34 containing a plurality of nozzles 33 that eject color ink, and a nozzle surface 31 on which the nozzles 33 are formed. The nozzle surface 31 constitutes the bottom surface of the ink head 32. The nozzle row 34 is a row in which a plurality of nozzles 33 are arranged in the sub-scanning direction X. The number of nozzle rows 34 is not particularly limited. In this embodiment, there are four nozzle rows 34. The four nozzle rows 34 are arranged in the main scanning direction Y. Here, the four nozzle rows 34 are the same length, their front ends are aligned, and their rear ends are aligned.

[0023] In this embodiment, each nozzle row 34 dispenses a different color of color ink. In the following description, "the nozzle row 34 dispenses color ink" means that the nozzles 33 constituting the nozzle row 34 dispense color ink. The color ink is a photocurable ink whose hardening is accelerated when irradiated with light. The light irradiated onto the color ink is, for example, ultraviolet light. Here, the color ink dispensed from the ink head 32 may be an ultraviolet-curable ink whose hardening is accelerated when irradiated with ultraviolet light. The color ink is not transparent, but a colored ink. The color ink is, for example, a process color ink. Here, each nozzle row 34 dispenses one of the following as a process color ink: yellow ink, magenta ink, black ink, or cyan ink. The nozzle row 34 has a nozzle row 34Y that dispenses yellow ink, a nozzle row 34M that dispenses magenta ink, a nozzle row 34K that dispenses black ink, and a nozzle row 34C that dispenses cyan ink. Here, the nozzle rows 34Y, 34M, 34K, and 34C are arranged from left to right, but the order of the nozzle rows 34 is not particularly limited. In this embodiment, for example, yellow ink is an example of a first color ink. For example, magenta ink is an example of a second color ink.

[0024] In this embodiment, the color ink ejected from the ink head 32 is contained in the ink cartridge 45 shown in Figure 2. The ink cartridge 45 includes an ink cartridge 45Y containing yellow ink, an ink cartridge 45M containing magenta ink, an ink cartridge 45K containing black ink, and an ink cartridge 45C containing cyan ink. For example, a storage section 46 is provided on the front left side of the printer body 11. The ink cartridge 45 is housed in the storage section 46. The ink cartridge 45 is connected to nozzles 33 that constitute a nozzle row 34 that ejects the corresponding color ink via ink tubes (not shown). The color ink contained in the ink cartridge 45 is supplied to the ink head 32 through the ink tubes.

[0025] As shown in Figure 2, the light irradiation device 35 irradiates light onto the workpiece 5 supported on the support base 25. Specifically, it irradiates light onto the color ink ejected onto the workpiece 5 supported on the support base 25. In this embodiment, as described above, the color ink ejected from the ink head 32 is an ultraviolet-curable ink whose hardening is accelerated when irradiated with ultraviolet light, for example. Therefore, the light irradiation device 35 can be an ultraviolet irradiation device that emits ultraviolet light. In this embodiment, the light irradiation device 35 is an example of a post-processing device that performs post-processing on the color ink ejected onto the workpiece 5. Here, as post-processing, the light irradiation device 35 irradiates light onto the color ink ejected onto the workpiece 5. "Post-processing" here refers to a process that makes the surface of the ink layer formed by the color ink matte or glossy. "Post-processing" can also be rephrased as a process that determines the unevenness of the color ink ejected onto the workpiece 5.

[0026] The light irradiation device 35 is mounted on the carriage 30 and is configured to move in the main scanning direction Y together with the carriage 30 and the ink head 32. However, the light irradiation device 35 does not necessarily have to be mounted on the carriage 30, and its position is not particularly limited as long as it can irradiate light onto the color ink ejected onto the workpiece 5 supported on the support base 25. For example, the light irradiation device 35 may be fixed to the printer body 11. Also, the number of light irradiation devices 35 is not particularly limited, but in this embodiment there are two. The light irradiation device 35 has a first light irradiation device 35A and a second light irradiation device 35B. The first light irradiation device 35A is mounted on the left side of the carriage 30. The second light irradiation device 35B is mounted on the right side of the carriage 30. The carriage 30 and the ink head 32 are positioned between the first light irradiation device 35A and the second light irradiation device 35B.

[0027] The configuration of the first light irradiation device 35A and the second light irradiation device 35B are the same. In the following description, the term "light irradiation device 35" will be used when describing something common to both the first light irradiation device 35A and the second light irradiation device 35B. In this embodiment, as shown in Figure 4, the light irradiation device 35 has an irradiation body 36 and a plurality of light sources 37. The irradiation body 36 is, for example, a rectangular parallelepiped and hollow. In this embodiment, the light irradiation device 35 (more specifically the first light irradiation device 35A and the second light irradiation device 35B) is sized such that a portion of it overlaps with the position of the ink head 32 in the sub-scanning direction X. Therefore, the irradiation body 36 extends in the sub-scanning direction X such that a portion of it overlaps with the position of the ink head 32 in the sub-scanning direction X. In this embodiment, the irradiation body 36 protrudes forward of the ink head 32 in the sub-scanning direction X. That is, the front end of the irradiation body 36 is located in front of the front end of the ink head 32. Furthermore, for example, when printing is performed by moving the object to be printed 5 backward, the irradiation body 36 should protrude behind the ink head 32 in the sub-scanning direction X. Also, for example, if the ink head 32 is configured to move in the sub-scanning direction X, the irradiation body 36 should protrude relative to the ink head 32 in the direction opposite to the direction of movement of the ink head 32 in the sub-scanning direction X.

[0028] In this embodiment, the irradiation body 36 is divided into a plurality of irradiation regions in the sub-scanning direction X. The plurality of irradiation regions are regions obtained by dividing the irradiation body 36 at equal intervals, but they do not have to be regions divided at equal intervals. Here, the irradiation body 36 has a first irradiation region AR11, a second irradiation region AR12, a third irradiation region AR13, and a fourth irradiation region AR14 as irradiation regions. The first irradiation region AR11 to the fourth irradiation region AR14 are arranged in order in the sub-scanning direction X. The first irradiation region AR11 is the region located furthest back of the irradiation body 36. The second irradiation region AR12 is located in front of the first irradiation region AR11 and is continuous with the first irradiation region AR11. The third irradiation region AR13 is located in front of the second irradiation region AR12 and is continuous with the second irradiation region AR12. The fourth irradiation area AR14 is located in front of the third irradiation area AR13 and is continuous with the third irradiation area AR13. Here, the irradiation areas are arranged in the order of first irradiation area AR11, second irradiation area AR12, third irradiation area AR13, and fourth irradiation area AR14, from rear to front in the sub-scanning direction X. The lengths of the sub-scanning direction X are the same for the first irradiation area AR11 to the fourth irradiation area AR14, but at least some of the lengths of the sub-scanning direction X may be different.

[0029] In this embodiment, the first irradiation area AR11 of the irradiation body 36 overlaps with the position of the ink head 32 (in other words, the nozzle row 34) in the sub-scanning direction X. The second irradiation area AR12, the third irradiation area AR13, and the fourth irradiation area AR14 are positioned in front of the ink head 32.

[0030] As shown in Figure 4, an irradiation port 38 is formed on the bottom surface of the irradiation body 36. The irradiation port 38 opens downwards. The shape of the irradiation port 38 is rectangular, but is not particularly limited. The irradiation port 38 is formed in the irradiation body 36 so as to extend across the first irradiation area AR11 to the fourth irradiation area AR14. The length of the irradiation port 38 in the sub-scanning direction X in each irradiation area AR11 to AR14 may be the same, or at least a part of it may be different. The light irradiation device 35 may or may not have a partition plate in the irradiation port 38 that separates each irradiation area AR11 to AR14. That is, adjacent irradiation areas AR11 to AR14 may or may not be separated by a partition plate.

[0031] The light source 37 emits light (in this case, ultraviolet light). In this embodiment, multiple light sources 37 are arranged inside the irradiation body 36. The multiple light sources 37 are arranged along the sub-scanning direction X. The multiple light sources 37 are arranged at equal intervals, but the distances between the light sources 37 may differ. Here, the positions of the multiple light sources 37 in the main scanning direction Y are the same, but they may be different. At least one light source 37 is arranged in each irradiation area AR11 to AR14 of the irradiation body 36. The number of light sources 37 arranged in each irradiation area AR11 to AR14 is not particularly limited and may be the same or different. In this embodiment, for the sake of explanation, three light sources 37 are arranged in each irradiation area AR11 to AR14, but in reality, many more light sources 37 may be arranged in each irradiation area AR11 to AR14.

[0032] The light source 37 can be switched on and off. In this embodiment, multiple light sources 37 can be switched on and off independently. The type of light source 37 is not particularly limited. Here, the light source 37 is a light-emitting diode (in other words, an LED). Since the light source 37 can be switched on and off independently, the light irradiation device 35 can turn the light (in other words, the light source 37) on or off independently for each irradiation area AR11 to AR14. The light source 37 may also be configured to allow adjustment of its illuminance (in other words, peak illuminance).

[0033] As shown in Figure 2, the printer 10 is equipped with a moving mechanism 50 that moves the ink head 32 and the workpiece 5 supported on the support base 25 relatively. The moving mechanism 50 has a first moving mechanism 51 that moves the carriage 30, ink head 32, and light irradiation device 35 relatively in the main scanning direction Y with respect to the support base 25 (more specifically, the workpiece 5 supported on the support base 25), and a second moving mechanism 52 that moves the workpiece 5 supported on the support base 25 relatively in the sub-scanning direction X with respect to the carriage 30, ink head 32, and light irradiation device 35. Although a detailed explanation of the configuration is omitted, the moving mechanism 50 also has a lifting mechanism 53 that raises and lowers the support base 25.

[0034] The first moving mechanism 51 is a mechanism that moves the carriage 30, ink head 32, and light irradiation device 35 in the main scanning direction Y. The configuration of the first moving mechanism 51 is not particularly limited. The first moving mechanism 51, although not shown in the figures, includes, for example, left and right pulleys, a belt, and a scan motor. The left pulley is provided around the left end of the guide rail 28, and the right pulley is provided around the right end of the guide rail 28. The belt is, for example, an endless belt and is wrapped around the left and right pulleys. The carriage 30 is attached and fixed to the belt. The scan motor is connected to one of the left and right pulleys. When the scan motor is driven, the pulley rotates, and the belt travels between the left and right pulleys. As a result, the ink head 32 and light irradiation device 35 move along the guide rail 28 in the main scanning direction Y, together with the carriage 30.

[0035] The second moving mechanism 52 moves the support base 25 in the sub-scanning direction X, thereby moving the workpiece 5 supported on the support base 25 in the sub-scanning direction X. The configuration of the second moving mechanism 52 is not particularly limited. Here, although not shown in the figures, the second moving mechanism 52 includes a support base carriage that supports the support base 25, and a pair of left and right slide rails that slidably support the support base carriage and extend in the sub-scanning direction X. Although not shown in the figures, the second moving mechanism 52 further includes a pair of front and rear slide pulleys provided in front of and behind the slide rails, and a slide belt wrapped around the pair of front and rear slide pulleys. The support base carriage is fixed to this slide belt. A feed motor is connected to one of the front and rear slide pulleys. Here, when the feed motor is driven and the slide belt moves, the support base 25 moves in the sub-scanning direction X together with the support base carriage. As a result, the workpiece 5 supported on the support base 25 also moves in the sub-scanning direction X.

[0036] As shown in Figure 2, the printer 10 is equipped with a control device 60. The control device 60 is a device that performs control related to printing. The configuration of the control device 60 is not particularly limited. The control device 60 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited. The control device 60 includes, for example, an interface (I / F) for receiving print data from an external device such as a host computer, a central processing unit (CPU) that executes instructions for the control program, a ROM (Read Only Memory) that stores the program executed by the CPU, a RAM (Random Access Memory) used as a working area for expanding the program, and a memory that stores the program and various data. The control device 60 is located inside the printer body 11. However, the control device 60 may be implemented by a computer installed outside the printer body 11. In this case, the control device 60 is preferably connected to the control board (not shown) of the printer 10 via wired or wireless communication.

[0037] In this embodiment, as shown in Figure 3, the control device 60 is communicatively connected to the operation panel 20 (specifically the display screen 21 and operation keys 22), the ink head 32, the light irradiation device 35 (specifically the light source 37), and the movement mechanism 50 (specifically the first movement mechanism 51, the second movement mechanism 52, and the lifting mechanism 53). The control device 60 controls the operation panel 20, the ink head 32, the light irradiation device 35, and the movement mechanism 50.

[0038] In this embodiment, the control device 60 comprises a storage unit 61, a first discharge control unit 71, a second discharge control unit 72, and a light irradiation control unit 73. Each of the control device 60 units 61, 71-73 may be implemented by one or more processors or by circuits. The light irradiation control unit 73 is an example of a post-processing control unit that controls a post-processing device (here, a light irradiation device 35) that performs post-processing. The control contents of the first discharge control unit 71, the second discharge control unit 72, and the light irradiation control unit 73 will be described later.

[0039] The configuration of the printer 10 according to this embodiment has been described above. In this embodiment, printing is performed on the workpiece 5 supported by the support base 25 by ejecting color ink from the ink head 32 toward the workpiece 5. When light from the light irradiation device 35 is irradiated onto the color ink ejected onto the workpiece 5, the hardening of the color ink is accelerated. Here, the time from when the color ink lands on the workpiece 5 until the light from the light irradiation device 35 irradiates the color ink ejected onto the workpiece 5 is called the elapsed time. Here, the gloss of the printed surface changes depending on the length of the elapsed time until the light is irradiated. Depending on the gloss of the printed surface, matte or glossy printing can be performed. Matte printing is printing where the gloss of the printed surface is small. Glossy printing is printing where the gloss of the printed surface is large. For example, if the elapsed time until the light is irradiated is short, the color ink hardens before it can wet and spread and become smooth, so the gloss of the printed surface is small and it becomes matte. On the other hand, if the time elapsed before light is applied is long, the color ink will wet and spread out, become smooth, and then harden, resulting in a glossier surface for the print.

[0040] Incidentally, the inventor of this application wants to perform printing that results in a glossy surface using only color ink (in other words, without using clear ink). However, when performing glossy printing using only color ink, the print quality sometimes deteriorates. Specifically, when printing is performed by increasing the time elapsed between the ejection of color ink onto the substrate 5 and the irradiation of light, bleeding, clumping, banding, etc., can occur, resulting in a deterioration of print quality. Therefore, in this embodiment, we propose a printing method that is less likely to deteriorate in print quality even when performing glossy printing using only color ink.

[0041] Figure 5 is a cross-sectional view showing a substrate 5 on which a first ink layer L1 and a second ink layer L2 are formed. In this embodiment, when performing gloss-finish printing, a printing method that is less prone to deterioration of print quality is realized by forming two ink layers on the substrate 5. Here, as shown in Figure 5, a first ink layer L1 is formed on the substrate 5, and a second ink layer L2 is formed on top of the first ink layer L1. The first ink layer L1 and the second ink layer L2 have the same size in plan view. That is, the area of ​​the first ink layer L1 and the second ink layer L2 is the same in plan view. The thicknesses of the first ink layer L1 and the second ink layer L2 may be different or the same. The first ink layer L1 and the second ink layer L2 are layers formed by color ink ejected from the ink head 32. The first ink layer L1 and the second ink layer L2 are printed on the substrate 5 based on the same print image. In this embodiment, the storage unit 61 of the control device 60 has a print image P1 (see Figure 3) to be printed stored in advance. The first ink layer L1 and the second ink layer L2 are formed on the substrate 5 by printing based on the print image P1. Here, the same print image P1 is printed twice on the substrate 5. In this embodiment, the surface of the first ink layer L1 is matte. The surface of the second ink layer L2 is glossy. As described above, since the second ink layer L2 is formed on top of the first ink layer L1, the outermost surface of the print is the surface of the second ink layer L2, resulting in a glossy print.

[0042] Next, the basic printing procedure will be explained following the flowchart in Figure 6. First, in step S101 in Figure 6, the first ejection control unit 71 in Figure 3 forms a first ink layer L1 (see Figure 5) on the workpiece 5 supported on the support base 25. Based on the print image P1 (see Figure 3) stored in the storage unit 61, the first ejection control unit 71 ejects color ink from the ink head 32 to form the first ink layer L1 on the workpiece 5. In this embodiment, the first ejection control unit 71 controls the first moving mechanism 51 to move the ink head 32 together with the carriage 30 in the forward direction Y1 of the main scanning direction Y. While the ink head 32 is moving in the forward direction Y1, the first ejection control unit 71 ejects color ink from the ink head 32 onto the workpiece 5 supported on the support base 25 based on the print image P1. After the ink head 32 moves in the forward direction Y1, the first ejection control unit 71 controls the second movement mechanism 52 to move the workpiece 5 supported on the support base 25 forward in the sub-scanning direction X. Subsequently, the first ejection control unit 71 controls the first movement mechanism 51 to move the ink head 32 in the return direction Y2 of the main scanning direction Y, while ejecting color ink from the ink head 32 onto the workpiece 5 supported on the support base 25 based on the printed image P1. After the ink head 32 moves in the return direction Y2, the first ejection control unit 71 controls the second movement mechanism 52 to move the workpiece 5 forward. Subsequently, by repeatedly ejecting color ink while the ink head 32 moves in the main scanning direction Y and moving the workpiece 5 in the sub-scanning direction X, a first ink layer L1 formed by color ink can be formed on the workpiece 5 supported on the support base 25.

[0043] Next, in step S102 of FIG. 6, the light irradiation control unit 73 in FIG. 3 irradiates light from the light irradiation device 35 toward the first ink layer L1 formed on the printed material 5. In the present embodiment, the light irradiation control unit 73 irradiates light toward the first ink layer L1 after the first elapsed time T1 has elapsed since the first ink layer L1 was formed by the first discharge control unit 71. By doing this, the surface of the first ink layer L1 can be made matte. The first elapsed time T1 is set as appropriate, and it is preferably a short time enough for the surface of the first ink layer L1 to become matte.

[0044] In the present embodiment, when the ink head 32 is moving in the main scanning direction Y by the first discharge control unit 71, the light irradiation device 35 also moves in the main scanning direction Y. The light irradiation control unit 73 controls lighting or extinguishing of each light source 37 of the light irradiation device 35 while the light irradiation device 35 is moving in the main scanning direction Y, so that the light is irradiated to the portion of the first ink layer L1 formed on the printed material 5 in the order in which the first elapsed time T1 has elapsed.

[0045] FIG. 7 is a plan view schematically showing the state of the light irradiation device 35 while the ink head 32 is moving in the forward direction Y1 when irradiating light on the first ink layer L1. FIG. 8 is a plan view schematically showing the state of the light irradiation device 35 while the ink head 32 is moving in the return direction Y2 when irradiating light on the first ink layer L1. In FIGS. 7, 8, etc., crosses are shown in the irradiation regions AR11 to AR14 where the light irradiation device 35 is turned off. In the present embodiment, when the carriage 30 is moving in the forward direction Y1 of the main scanning direction Y, the light irradiation control unit 73 lights all of the first irradiation region AR11 to the fourth irradiation region AR14 of the first light irradiation device 35A provided on the left side of the carriage 30 as shown in FIG. 7. At this time, all of the first irradiation region AR11 to the fourth irradiation region AR14 of the second light irradiation device 35B are turned off. By doing this, when the ink head 32 is moving in the forward direction Y1, the portion of the first ink layer L1 formed on the printed material 5 is not irradiated with light immediately after the color ink lands on the printed material 5, and thereafter, light is irradiated after the carriage 30 starts moving in the return direction Y2.

[0046] On the other hand, when the carriage 30 is moving in the return direction Y2 of the main scanning direction Y, the light irradiation control unit 73 illuminates all of the first irradiation area AR11 to the fourth irradiation area AR14 of the second light irradiation device 35B, which is located to the right of the carriage 30, as shown in Figure 8. At this time, all of the first irradiation area AR11 to the fourth irradiation area AR14 of the first light irradiation device 35A are turned off. As a result, when the ink head 32 is moving in the return direction Y2, the portion of the first ink layer L1 formed on the workpiece 5 is not illuminated by light immediately after the color ink lands on the workpiece 5, and is only illuminated by light after the carriage 30 is moving in the forward direction Y1.

[0047] In this embodiment, the formation of the first ink layer L1 in step S101 and the irradiation of the first ink layer L1 with light in step S102 in Figure 6 are performed sequentially until the workpiece 5 has finished moving forward in the sub-scanning direction X. Here, when the ink head 32 is moving in the main scanning direction Y, the formation of a portion of the first ink layer L1 and the irradiation of light to the portion of the first ink layer L1 that was formed immediately before that portion of the first ink layer L1 are performed at the same timing. Here, the printing of the first ink layer L1 is completed when steps S101 and S102 are performed. In this embodiment, the time from when the color ink lands on the portion of the first ink layer L1 formed when the ink head 32 is moving in the forward direction Y1 until the first irradiation of light from the second light irradiation device 35B when the carriage 30 is moving in the return direction Y2 may be the first elapsed time T1. On the other hand, in the portion of the first ink layer L1 formed when the ink head 32 is moving in the return direction Y2, the time from when the color ink lands until the first light from the first light irradiation device 35A is irradiated when the carriage 30 is moving in the forward direction Y1 can be the first elapsed time T1. Thus, in step S102 of Figure 6, by irradiating the first ink layer L1 formed on the substrate 5 with light after the first elapsed time T1 has elapsed since the color ink landed, the surface of the first ink layer L1 can be made matte.

[0048] Next, in step S103 of FIG. 6, as shown in FIG. 5, the second ejection control unit 72 in FIG. 3 forms a second ink layer L2 on the first ink layer L1. Based on the printed image P1 (see FIG. 3) stored in the storage unit 61, the second ejection control unit 72 ejects color ink from the ink head 32 to form a second ink layer L2 on the first ink layer L1 formed on the printed material 5. In the present embodiment, after steps S101 and S102 in FIG. 6 are executed, the first ink layer L1 formed on the printed material 5 may be located in front of the ink head 32. Therefore, the second ejection control unit 72 controls the second movement mechanism 52 so that in the first ink layer L1, one part overlaps the ink head 32 in the sub-scanning direction X and the other part is located behind the ink head 32, and moves the printed material 5 backward in the sub-scanning direction X. After that, the second ejection control unit 72 forms the second ink layer L2 on the first ink layer L1 by performing the same control as the first ejection control unit 71. Although detailed description is omitted, the second ejection control unit 72 repeats the ejection of color ink during the movement of the ink head 32 in the main scanning direction Y and the movement of the printed material 5 in the sub-scanning direction X, similar to the control by the first ejection control unit 71, to form the second ink layer L2 on the first ink layer L1 formed on the printed material 5 supported by the support base 25.

[0049] Next, in step S104 of FIG. 6, the light irradiation control unit 73 in FIG. 3 irradiates light from the light irradiation device 35 toward the second ink layer L2 formed on the printed material 5. In the present embodiment, the light irradiation control unit 73 irradiates light toward the second ink layer L2 after the second elapsed time T2 has elapsed since the second ink layer L2 was formed by the second ejection control unit 72. Here, by irradiating light after the second elapsed time T2 has elapsed, the surface of the second ink layer L2 is made glossy.

[0050] In this embodiment, the second elapsed time T2 is set as appropriate, and it is preferable that it is a long enough time for the surface of the second ink layer L2 to become glossy rather than matte. Here, the second elapsed time T2 is longer than the first elapsed time T1. For example, the second elapsed time T2 is at least twice the first elapsed time T1, preferably at least five times, and more preferably at least ten times.

[0051] In this embodiment, when the ink head 32 is moving in the main scanning direction Y by the second ejection control unit 72, the light irradiation control unit 73 controls the on / off of the light source 37 of the light irradiation device 35 while the light irradiation device 35 is moving in the main scanning direction Y together with the ink head 32, so that light is irradiated onto the portion of the second ink layer L2 formed on the workpiece 5 in the order in which the second elapsed time T2 has elapsed. Figure 9 is a schematic plan view showing the state of the light irradiation device 35 when irradiating the second ink layer L2 with light. In step S104, as shown in Figure 9, the light irradiation control unit 73 turns on the fourth irradiation area AR14 of the first light irradiation device 35A and the fourth irradiation area AR14 of the second light irradiation device 35B. At this time, the first irradiation areas AR11 to the third irradiation areas AR13 of the first light irradiation device 35A and the first irradiation areas AR11 to the third irradiation areas AR13 of the second light irradiation device 35B are turned off.

[0052] In this embodiment, the formation of the second ink layer L2 in step S103 of Figure 6 and the irradiation of the second ink layer L2 with light in step S104 are performed sequentially until the workpiece 5 has finished moving forward in the sub-scanning direction X. Here, when the ink head 32 is moving in the main scanning direction Y, the formation of a portion of the second ink layer L2 and the irradiation of light to the portion of the second ink layer L2 that was formed in front of that portion are performed at the same time. Here, the printing of the second ink layer L2 is completed when steps S103 and S103 are executed. In this embodiment, the portion of the second ink layer L2 formed by the color ink ejected from the ink head 32 moves forward in the sub-scanning direction X until the position in the sub-scanning direction X reaches the position in the sub-scanning direction X of the fourth irradiation area AR14. Then, when the light irradiation device 35 moves in the main scanning direction Y while the sub-scanning direction X is at the position of the fourth irradiation area AR14, the second ink layer L2 is irradiated with light from the fourth irradiation area AR14. The time from when the color ink ejected from the ink head 32 lands on the second ink layer L2 until the light from the fourth irradiation area AR14 of the light irradiation device 35 is irradiated is the second elapsed time T2. In this way, in step S104, by irradiating the second ink layer L2 formed on the substrate 5 with light after the second elapsed time T2 has elapsed since the color ink landed, the surface of the second ink layer L2 can be made glossy. By printing the print image P1 on the substrate 5 using the above printing method, a glossy finish can be achieved.

[0053] Incidentally, there are two types of color inks: those with high light absorption and those with low light absorption. In this embodiment, a color ink whose light absorption to the light (in this case, ultraviolet light) irradiated from the light irradiation device 35 is higher than a standard value is called a high-absorption color ink. On the other hand, a color ink whose light absorption to the ultraviolet light irradiated from the light irradiation device 35 is lower than a standard value is called a low-absorption color ink. However, high-absorption and low-absorption color inks may also be defined based on their light absorption to light other than ultraviolet light. Here, the type of parameter indicating light absorption is not particularly limited, but for example, light absorption can be indicated by absorbance or light absorption coefficient. In this case, the above standard value may be a standard value for absorbance or light absorption coefficient. The standard value is an arbitrary value and may be set according to, for example, the components contained in the color ink. In this embodiment, the high-absorption color inks are yellow ink and black ink, which are inks of colors that easily absorb ultraviolet light. The low-absorption color inks are cyan ink and magenta ink, which are inks of colors that do not easily absorb ultraviolet light. It should also be considered that the light absorption of color inks may change depending on the components contained in the color inks. For example, even with the same color ink, an ink containing a large amount of components that easily absorb ultraviolet light will be a high-absorption ink, while an ink containing only a small amount of such components will be a low-absorption ink.

[0054] In this embodiment, the inventors discovered that when printing to achieve a glossy finish, the amount of ink used can affect the glossiness of the printed surface, depending on the color of the ink. Here, in the case of low-absorption color inks such as cyan and magenta, even when the amount of ink is increased, a relatively high-gloss print quality can be maintained when printing to a glossy finish. On the other hand, in the case of high-absorption color inks such as yellow and black, increasing the amount of ink to achieve a glossy finish may reduce the glossiness of the printed surface.

[0055] Therefore, in this embodiment, the amount of ink discharged to the first ink layer L1 and the amount of ink discharged to the second ink layer L2 are adjusted for at least one of the multiple color inks discharged from the ink head 32 (here, for each color ink). Figure 10 is a table showing the relationship between the first ink amount V1 and the second ink amount V2 for low absorption color ink and high absorption color ink. In the following description, as shown in Figure 10, the amount of color ink used to form the first ink layer L1 is called the first ink amount V1. The amount of color ink used to form the second ink layer L2 is called the second ink amount V2. Here, the first ink amount V1 and the second ink amount V2 are different values. The first discharge control unit 71 in Figure 3 discharges the color ink by the first ink amount V1 to form the first ink layer L1 on the material to be printed 5. The second discharge control unit 72 in Figure 3 discharges the color ink by the second ink amount V2 to form the second ink layer L2 on the material to be printed 5. The first ink amount V1 and the second ink amount V2 may be the amount of color ink dispensed over the entire ink layer, or the amount of color ink dispensed per unit area of ​​each ink layer.

[0056] In this embodiment, as described above, the ink head 32 is configured to eject multiple color inks of different colors (here, cyan ink, magenta ink, yellow ink, and black ink). Here, the relationship between the first ink amount V1 and the second ink amount V2 differs for each color ink. In this embodiment, the relationship between the first ink amount V1 and the second ink amount V2 is determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35.

[0057] Figure 11 is a graph showing the reflectance density according to the amount of second ink V2 in the second ink layer L2 for cyan, magenta, yellow, and black inks. In the graph of Figure 11, the amount of second ink V2 is shown as a ratio of the sum of the amount of first ink V1 and the amount of second ink V2 for each color ink. A higher reflectance density indicates a higher gloss and a more glossy finish. As shown in Figure 11, in the case of low-absorption color inks such as cyan and magenta inks, it can be seen that, generally, the reflectance density tends to increase as the amount of second ink V2 increases. Therefore, as shown in Figure 10, for low-absorption color inks, the amount of second ink V2 is made greater than the amount of first ink V1. That is, printing is performed so that the amount of low-absorption color ink in the second ink layer L2 is greater than that in the first ink layer L1.

[0058] On the other hand, as shown in Figure 11, in the case of highly absorbent color inks such as yellow ink and black ink, the reflectance tends to be higher when the amount of the second ink V2 is less (for example, when the amount of the second ink V2 is about 10% to 20%) than when the amount of the second ink V2 is large (for example, when the amount of the second ink V2 is about 90%). Therefore, as shown in Figure 10, with highly absorbent color inks, the amount of the second ink V2 is made less than the amount of the first ink V1. That is, printing is performed so that the amount of highly absorbent color ink in the second ink layer L2 is less than that in the first ink layer L1.

[0059] In this embodiment, the relative magnitudes of the first ink amount V1 and the second ink amount V2 differ for each color of color ink. However, the first ink layer L1 and the second ink layer L2 are formed such that the sum of the first ink amount V1 and the second ink amount V2 for each color of color ink is the same as the amount of color ink when the printed image P1 (see Figure 3) is printed as a single print layer in the conventional way (hereinafter also referred to as the conventional printing method). In other words, in this embodiment, the amount of color ink when the printed image P1 is conventionally printed is distributed between the first ink amount V1 and the second ink amount V2. The sum of the first ink amount V1 and the second ink amount V2 for high-absorption color ink is the same as the amount of high-absorption color ink when the printed image P1 is conventionally printed. Similarly, the sum of the first ink amount V1 and the second ink amount V2 for low-absorption color ink is the same as the amount of low-absorption color ink when the printed image P1 is conventionally printed. However, the sum of the first ink amount V1 and the second ink amount V2 for each color ink does not have to be the same as the amount of color ink used when printing the print image P1 conventionally. For example, if you want to print with a thick layer (printing with thickness), the sum of the first ink amount V1 and the second ink amount V2 for each color ink may be greater than the amount of color ink used when printing the print image P1 conventionally.

[0060] Figure 12 is a graph showing the reference distribution table TB1. In this embodiment, when simply printing a print image P1 (in other words, when conventionally printing a print image P1 with only one ink layer without forming multiple ink layers L1 and L2 as shown in Figure 5), the amount of color ink ejected can be adjusted using, for example, the reference distribution table TB1 shown in Figure 12.

[0061] Here, the ink head 32 is configured to eject multiple ink dots of different diameters in color ink. In this embodiment, the ink head 32 is capable of ejecting three ink dots of different diameters. The ink head 32 is capable of ejecting ink dots of a first size, a second size, and a third size. Here, as shown in Figure 12, the first size ink dot is called an S dot D1. The first size is an example of the smallest size. The second size is a size with a larger diameter than the first size. The second size ink dot is called an M dot D2. The third size is a size with a larger diameter than the second size. The third size ink dot is called an L dot D3.

[0062] The reference distribution table TB1 in Figure 12 shows the distribution (in other words, the proportion) of S dots D1, M dots D2, and L dots D3 to the grayscale value of the printed image P1. For example, according to the reference distribution table TB1, when the grayscale value is 80%, the proportion of S dots D1 is approximately 5%, the proportion of M dots D2 is approximately 75%, and the proportion of L dots D3 is approximately 25%. Therefore, in the printed image P1, of the pixels with a grayscale value of 80%, approximately 5% of the pixels will have S dots D1 ejected, approximately 75% of the pixels will have M dots D2 ejected, and approximately 25% of the pixels will have L dots D3 ejected. Here, in the reference distribution table TB1 in Figure 12, the grayscale value is expressed as a proportion, but the grayscale value may also be expressed as a value from 0 to 255, for example. For example, in the reference distribution table TB1, when the grayscale value is around 20%, the proportion of S dots D1 is the largest. When the grayscale value is around 70%, the proportion of M dots D2 is the largest. Furthermore, when the grayscale value is around 100%, the proportion of L-dot D3 is the largest.

[0063] Figures 13 and 14 are graphs showing the first distribution table TB11 used when forming the first ink layer L1. Figures 15 and 16 are graphs showing the second distribution table TB12 used when forming the second ink layer L2. Figures 13 and 15 show the distribution table for low-absorption color inks. Figures 14 and 16 show the distribution table for high-absorption color inks. In this embodiment, the first distribution table TB11 (see Figures 13 and 14) used when forming the first ink layer L1 and the second distribution table TB12 (see Figures 15 and 16) used when forming the second ink layer L2 are pre-set based on the reference distribution table TB1. As shown in Figures 13 and 14, the distribution of S dot D1, M dot D2, and L dot D3 in the first distribution table TB11 is called the first distribution A1. As shown in Figures 15 and 16, the allocation of S dot D1, M dot D2, and L dot D3 in the second allocation table TB12 is called the second allocation A2. The first allocation A1 and the second allocation A2 have different allocations.

[0064] In this embodiment, the proportion of S dots D1 to each of the first and second distributions is called the S size proportion. The proportion of M dots D2 to each of the first and second distributions is called the M size proportion. The proportion of L dots D3 to each of the first and second distributions is called the L size proportion. In this embodiment, the S size proportion, M size proportion, and L size proportion are proportions based on the grayscale value. Here, the M size proportion is an example of the second size proportion. In this embodiment, for any grayscale value, the S size proportion and M size proportion are higher in the first distribution A1 of the first distribution table TB11 than in the second distribution A2 of the second distribution table TB12. Specifically, in the second distribution A2 of the second distribution table TB12, the S size proportion and M size proportion are zero for any grayscale value. That is, S dots D1 and M dots D2 are not used when forming the second ink layer L2.

[0065] The first ejection control unit 71 in Figure 3 ejects color ink based on the first distribution table TB11 so that the distribution of each size of the ink head 32 becomes the first distribution A1 (see Figures 13 and 14), thereby forming the first ink layer L1. The second ejection control unit 72 in Figure 3 ejects color ink based on the second distribution table TB12 so that the distribution of each size of the ink head 32 becomes the second distribution A2 (see Figures 15 and 16), thereby forming the second ink layer L2.

[0066] In this embodiment, the proportions of S size, M size, and L size in the first distribution A1 and the second distribution A2 differ for each color of color ink. Furthermore, the proportions of S size, M size, and L size in the first distribution A1 and the second distribution A2 are determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35. In this embodiment, the distribution table used differs depending on whether low-absorption color ink or high-absorption color ink is being discharged.

[0067] The first distribution table TB11, used when forming the first ink layer L1, includes a first low distribution table TB11a (see Figure 13) used when ejecting low-absorption color inks (here, cyan ink and magenta ink), and a first high distribution table TB11b (see Figure 14) used when ejecting high-absorption color inks (here, yellow ink and black ink). The second distribution table TB12, used when forming the second ink layer L2, includes a second low distribution table TB12a (see Figure 15) used when ejecting low-absorption color ink, and a second high distribution table TB12b (see Figure 16) used when ejecting high-absorption color ink.

[0068] In this embodiment, as shown in Figures 13 and 14, the first distribution A1 of the first high-distribution table TB11b (here, the first distribution A1 for high-absorption color inks) and the first distribution A1 of the first low-distribution table TB11a (here, the first distribution A1 for low-absorption color inks) include S dots D1, M dots D2, and L dots D3. The proportion of S size in the first distribution A1 of the first high-distribution table TB11b is the same as the proportion of S size in the first distribution A1 of the first low-distribution table TB11a. The proportion of M size in the first distribution A1 of the first high-distribution table TB11b is greater than the proportion of M size in the first distribution A1 of the first low-distribution table TB11a. Also, the proportion of L size in the first distribution A1 of the first high-distribution table TB11b is greater than the proportion of L size in the first distribution A1 of the first low-distribution table TB11a.

[0069] In this embodiment, as shown in Figures 15 and 16, the second distribution A2 of the second high-distribution table TB12b (here, the second distribution A2 for high-absorption color inks) and the second distribution A2 of the second low-distribution table TB12a (here, the second distribution A2 for low-absorption color inks) include L dots D3, but do not include S dots D1 and M dots D2. The proportion of L size in the second distribution A2 of the second high-distribution table TB12b is smaller than the proportion of L size in the second distribution A2 of the second low-distribution table TB12a.

[0070] In this embodiment, the first ejection control unit 71 in Figure 3 controls the ejection of low-absorption color inks (here, cyan ink and magenta ink) from nozzle rows 34C and 34M (see Figure 4) based on the first low-distribution table TB11a in Figure 13, and to eject high-absorption color inks (here, yellow ink and black ink) from nozzle rows 34Y and 34K (see Figure 4) based on the first high-distribution table TB11b in Figure 14. The second ejection control unit 72 in Figure 3 controls the ejection of low-absorption color inks from nozzle rows 34C and 34M based on the second low-distribution table TB12a in Figure 15, and to eject high-absorption color inks from nozzle rows 34Y and 34K based on the second high-distribution table TB12b in Figure 16, when forming the second ink layer L2 on the first ink layer L1. This allows for adjustment of the first ink amount V1 and the second ink amount V2 for each color of the color ink.

[0071] In this embodiment, the first ejection control unit 71 ejects color ink from the ink head 32 in step S101 of Figure 6 to form a first ink layer L1 on the workpiece 5 supported by the support base 25. The second ejection control unit 72 ejects color ink from the ink head 32 in step S103 of Figure 6 to form a second ink layer L2 on top of the first ink layer L1. The light irradiation control unit 73 in Figure 3 is an example of a post-processing control unit and controls a light irradiation device 35, which is an example of a post-processing device. In step S102 of Figure 6, the light irradiation control unit 73 controls the light irradiation device 35 so that the surface of the first ink layer L1 becomes matte. Specifically, the light irradiation control unit 73 irradiates light onto the first ink layer L1 after a first elapsed time T1 has elapsed since the first ejection control unit 71 formed the first ink layer L1. Furthermore, in step S104 of Figure 6, the light irradiation control unit 73 controls the light irradiation device 35 so that the surface of the second ink layer L2 becomes glossy. Specifically, the light irradiation control unit 73 irradiates light toward the second ink layer L2 after a second elapsed time T2, which is longer than the first elapsed time T1, has elapsed since the second ink layer L2 was formed by the second ejection control unit 72.

[0072] In this way, by irradiating the first ink layer L1 with light after a first elapsed time T1 has elapsed since its formation, the first ink layer L1 can be made matte. Furthermore, by irradiating the second ink layer L2 with light after a second elapsed time T2 has elapsed since its formation, the second ink layer L2 can be made glossy. As a result, even when printing using only color inks, it is possible to achieve glossy printing while minimizing the deterioration of print quality.

[0073] In this embodiment, as shown in Figure 10, the first dispensing control unit 71 dispensing a first ink amount V1 of color ink to form the first ink layer L1. The second dispensing control unit 72 dispensing a second ink amount V2 of color ink, which is a different amount from the first ink amount V1, to form the second ink layer L2. By making the ink amounts different in the first ink layer L1 and the second ink layer L2 in this way, it is possible to adjust the degree of glossiness, especially in the second ink layer L2.

[0074] In this embodiment, as shown in Figure 10, the relative magnitudes of the first ink amount V1 and the second ink amount V2 differ for each color of the color ink. Here, the relative magnitudes of the first ink amount V1 and the second ink amount V2 are determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35. As a result, by adjusting the first ink amount V1 and the second ink amount V2 for each color of the color ink, the degree of glossiness in the second ink layer L2 can be adjusted for each color of the color ink. In particular, the degree of glossiness may differ depending on the light absorption of the color ink. Therefore, by adjusting the first ink amount V1 and the second ink amount V2 according to the light absorption of the color ink, the degree of glossiness can be appropriately adjusted.

[0075] In this embodiment, as shown in Figure 10, in the case of a high-absorption color ink, which is a color ink with light absorption higher than a standard value, the amount of the second ink V2 is less than the amount of the first ink V1. In the case of a low-absorption color ink, which is a color ink with light absorption lower than a standard value, the amount of the second ink V2 is greater than the amount of the first ink V1. For example, in the case of a high-absorption color ink, if the amount of the second ink V2 in the second ink layer L2 that becomes glossy is increased, the degree of gloss may decrease. However, in this embodiment, since the amount of the second ink V2 in the second ink layer L2 that becomes glossy is reduced in the case of a high-absorption color ink, the degree of gloss is less likely to decrease.

[0076] In this embodiment, the sum of the first ink amount V1 and the second ink amount V2 is the same as the sum of the ink amounts based on the printed image P1 (see Figure 3) (in other words, the sum of the ink amounts when the printed image P1 is printed as a single print layer as in the conventional method (conventional printing)). This makes it possible to achieve the same color intensity as in conventional printing.

[0077] In this embodiment, as shown in Figure 12, the ink head 32 is configured to eject multiple ink dots of different sizes with different diameters in the color ink (here, S dot D1, M dot D2, and L dot D3). The first ejection control unit 71 in Figure 3 ejects color ink so that the distribution of each ink dot size is the first distribution A1 (see Figures 13 and 14) to form the first ink layer L1. The second ejection control unit 72 in Figure 3 ejects color ink so that the distribution of each ink dot size is the second distribution A2 (see Figures 15 and 16), which is different from the first distribution A1, to form the second ink layer L2. In this way, by adjusting the distribution of each ink dot size when forming the second ink layer L2, the degree of glossiness in the second ink layer L2 can be adjusted.

[0078] In this embodiment, the ink head 32 is configured to eject ink dots of multiple sizes for each color of the color ink. The proportion of M-size dots in at least one of the first distribution A1 and the second distribution A2 (here, the first distribution A1) differs for each color of the color ink. By adjusting the distribution of the proportion of M-size dots D2 in this way, it is possible to more easily adjust the degree of glossiness in the second ink layer L2. Note that M-size dots D2 may also be included in the second distribution A2. In this case, the proportion of M-size dots in the second distribution A2 may differ for each color of the color ink.

[0079] In this embodiment, the M size ratio is determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35. As described above, the degree of gloss may differ depending on the light absorption of the color ink. Therefore, by adjusting the M size ratio according to the light absorption of the color ink, the degree of gloss can be appropriately adjusted.

[0080] In this embodiment, the proportion of M-size particles in the first distribution A1 (see Figure 14) of the high-absorption color ink is greater than the proportion of M-size particles in the first distribution A1 (see Figure 13) of the low-absorption color ink. Here, the proportion of M-size particles when forming the first ink layer L1 to create a matte finish can be increased in the high-absorption color ink, thereby increasing the amount of high-absorption color ink in the first ink layer L1. This suppresses the high-absorption color ink in the first ink layer L1 from becoming glossy. Therefore, the surface of the first ink layer L1 in the high-absorption color ink can be adjusted to a matte finish.

[0081] In this embodiment, the smallest ink dot among the multiple ink dot sizes that the ink head 32 can eject is the S dot D1. As shown in Figures 13 and 14, the proportion of S-size dots in the first distribution A1 is the same for both high-absorption color ink and low-absorption color ink. Here, the smallest size, S dot D1, is an ink dot that easily produces a granular texture. Therefore, by making the proportion of S-size dots in the first distribution A1 the same for both high-absorption color ink and low-absorption color ink, it is possible to prevent a decrease in print quality.

[0082] In this embodiment, as shown in Figures 15 and 16, the second distribution A2 does not include the smallest ink dot (here, S dot D1) and M dot D2 among the multiple ink dot sizes that the ink head 32 can eject. Here, the second distribution table TB12, which is the second distribution A2, is used to form the second ink layer L2, which will have a glossy finish. When performing glossy printing, ejecting the color ink of L dot D3 rather than S dot D1 and M dot D2 makes it easier to wet and spread, resulting in a glossy finish. Therefore, by not including small-sized ink dots in the second distribution A2, it is possible to easily form the glossy second ink layer L2.

[0083] <Second Embodiment> Next, a printer 10A according to the second embodiment will be described. Figure 17 is a schematic diagram showing the configuration of the bottom surface of the ink head 32A and the light irradiation device 35 in the printer 10A according to the second embodiment. In this embodiment, the printer 10A is equipped with an ink head 32A. Apart from the configuration of the ink head 32A, the printer 10A has the same basic configuration as the printer 10 according to the first embodiment, except for the control during printing. Explanations that overlap with those of the printer 10 will be omitted as appropriate.

[0084] In this embodiment, the ink head 32A has the same configuration as the ink head 32 in the first embodiment, except that the length in the sub-scanning direction X is different. For example, as shown in Figure 17, the ink head 32A has a plurality of nozzle rows 34 composed of a plurality of nozzles 33 arranged in the sub-scanning direction X, similar to the ink head 32 in the first embodiment. In this embodiment, the printer 10A may differ from the first embodiment only in the length in the sub-scanning direction X of each ejection area of ​​the light irradiation device 35 (here, the first irradiation area AR11 to the fourth irradiation area AR14). That is, in this embodiment, only the relative positional relationship between the ink head 32 and each irradiation area of ​​the light irradiation device 35 differs from the first embodiment, and the positional relationship is as shown in detail in Figure 17.

[0085] The ink head 32A (in other words, each nozzle row 34) is positioned in the sub-scanning direction X, overlapping with the first irradiation area AR11 and the second irradiation area AR12 of the light irradiation device 35 (more specifically, the first light irradiation device 35A and the second light irradiation device 35B). The third irradiation area AR13 and the fourth irradiation area AR14 of the light irradiation device 35 are located in front of the ink head 32A.

[0086] As shown in Figure 17, each nozzle row 34 of the ink head 32A has a first ejection area AR21 and a second ejection area AR22. The first ejection area AR21 is a region formed by nozzles 33 located on the rear side when the nozzle row 34 is divided into two (here, into two equal parts) in the sub-scanning direction X. The second ejection area AR22 is located in front of the first ejection area AR21 and is continuous with the first ejection area AR21. However, the first ejection area AR21 and the second ejection area AR22 do not have to be continuous. For example, the first ejection area AR21 and the second ejection area AR22 may be spaced apart, and nozzles 33 that do not eject ink may be placed between the first ejection area AR21 and the second ejection area AR22. The second ejection area AR22 is a region formed by nozzles 33 located on the front side when the nozzle row 34 is divided into two in the sub-scanning direction X. Here, the first ejection region AR21 is positioned to overlap with the first irradiation region AR11 of the light irradiation device 35 (specifically, the first light irradiation device 35A and the second light irradiation device 35B) in the sub-scanning direction X. The second ejection region AR22 is positioned to overlap with the second irradiation region AR12 of the light irradiation device 35 in the sub-scanning direction X. In this embodiment, the ink head 32A is configured to form a printed image P1 separately in the first ejection region AR21 and the second ejection region AR22. That is, it is possible to form a first ink layer L1 by ejecting color ink from the nozzle 33 included in the first ejection region AR21, and to form a second ink layer L2 by ejecting color ink from the nozzle 33 included in the second ejection region AR22.

[0087] In this embodiment as well, printing is performed according to the flowchart in Figure 6, similar to the first embodiment. In step S101 of Figure 6, the first ejection control unit 71 of Figure 3 ejects color ink from the first ejection area AR21 of the ink head 32A onto the workpiece 5 supported by the support base 25, thereby forming a first ink layer L1 (see Figure 5) on the workpiece 5. In step S103 of Figure 6, the second ejection control unit 72 of Figure 3 ejects color ink from the second ejection area AR22 of the ink head 32A onto the first ink layer L1 formed on the workpiece 5, thereby forming a second ink layer L2 (see Figure 5) on top of the first ink layer L1. Here, the first ink layer L1 is formed by the color ink ejected from the first ejection area AR21. Subsequently, when the workpiece 5 moves forward in the sub-scanning direction X and the ink head 32A moves in the main scanning direction Y, the second ink layer L2 is formed on top of the first ink layer L1 by the color ink ejected from the second ejection area AR22. In this embodiment, when the ink head 32A is moving in the main scanning direction Y, the formation of the first ink layer L1 and the second ink layer L2 can be performed simultaneously in different printing areas of the material to be printed 5.

[0088] Figure 18 is a schematic plan view showing the state of the light irradiation device 35 while the ink head 32A is moving in the forward direction Y1 in this embodiment. Figure 19 is a schematic plan view showing the state of the light irradiation device 35 while the ink head 32A is moving in the return direction Y2. In this embodiment, while the carriage 30 is moving in the forward direction Y1 of the main scanning direction Y during printing, the light irradiation control unit 73 in Figure 3 illuminates the first irradiation area AR11 and the fourth irradiation area AR14 of the first light irradiation device 35A, and the fourth irradiation area AR14 of the second light irradiation device 35B, as shown in Figure 18. At this time, the second irradiation area AR12 and the third irradiation area AR13 of the first light irradiation device 35A, and the first irradiation areas AR11 to the third irradiation areas AR13 of the second light irradiation device 35B are turned off. Meanwhile, while the carriage 30 is moving in the return direction Y2 of the main scanning direction Y, the light irradiation control unit 73 illuminates the fourth irradiation area AR14 of the first light irradiation device 35A and the first irradiation area AR11 and fourth irradiation area AR14 of the second light irradiation device 35B, as shown in Figure 19. At this time, the first irradiation area AR11 to the third irradiation area AR13 of the first light irradiation device 35A and the second irradiation area AR12 and third irradiation area AR13 of the second light irradiation device 35B are turned off.

[0089] As a result, the first ink layer L1 formed on the substrate 5 in step S101 of Figure 6 is irradiated with light from the first irradiation area AR11 of the first light irradiation device 35A or the first irradiation area AR11 of the second light irradiation device 35B in step S102 of Figure 6. Therefore, the first ink layer L1 is irradiated with light after a first elapsed time T1 has elapsed following the color ink's impact. As a result, the surface of the first ink layer L1 can be made matte. Furthermore, the second ink layer L2 formed on top of the first ink layer L1 in step S103 of Figure 6 is irradiated with light from the fourth irradiation area AR14 of the first light irradiation device 35A and the fourth irradiation area AR14 of the second light irradiation device 35B in step S104 of Figure 6. Therefore, the second ink layer L2 is irradiated with light after a second elapsed time T2 has elapsed following the color ink's impact. As a result, the surface of the second ink layer L2 can be made glossy.

[0090] In this embodiment, the ink head 32A adjusts the amount of ink ejected from the nozzle 33 by using a pass mask. A pass mask is a set ratio for which color ink ejection is permitted for each nozzle 33 of the nozzle row 34 while the ink head 32A is moving in one direction of the main scanning direction Y (here, the forward direction Y1 or the return direction Y2). Here, the amount of color ink ejected is adjusted by using different pass masks when forming the first ink layer L1 and when forming the second ink layer L2.

[0091] Figure 20 shows the relationship between the first pass mask M1 and the second pass mask M2 used when ejecting low-absorption color ink and the nozzle row 34. Figure 21 shows the relationship between the first pass mask M1 and the second pass mask M2 used when ejecting high-absorption color ink and the nozzle row 34. In Figures 20 and 21, in the graphs showing the first pass mask M1 and the second pass mask M2, the vertical axis shows the position of the nozzle 33 relative to the nozzle row 34, and the horizontal axis shows the allowable ratio of each nozzle 33. Here, the allowable ratio is the ratio of the number of dots (pixels) that are allowed to be ejected to the maximum number of dots (pixels) that can be ejected from the nozzle 33 while the ink head 32A is moving in one direction of the main scanning direction Y. In this embodiment, the first discharge control unit 71 in Figure 3 discharges color ink from nozzles 33 included in the first discharge region AR21 of the nozzle row 34 according to the first pass mask M1, as shown in Figures 20 and 21, to form a first ink layer L1 on the material to be printed 5. The second discharge control unit 72 in Figure 3 discharges color ink from nozzles 33 included in the second discharge region AR22 of the nozzle row 34 according to the second pass mask M2, to form a second ink layer L2 on top of the first ink layer L1 on the material to be printed 5. That is, the first pass mask M1 is a pass mask corresponding to the nozzles 33 included in the first discharge region AR21 of the nozzle row 34, and the second pass mask M2 is a pass mask corresponding to the nozzles 33 included in the second discharge region AR22 of the nozzle row 34.

[0092] The first pass mask M1 and the second pass mask M2 are different pass masks. Different pass masks mean that the proportion of color ink ejection allowed is different. In this embodiment, the proportion of color ink ejection allowed in the first pass mask M1 is called the first allowable proportion R1. The proportion of color ink ejection allowed in the second pass mask M2 is called the second allowable proportion R2. In this embodiment, the relative magnitudes of the first allowable proportion R1 in the first pass mask M1 and the second allowable proportion R2 in the second pass mask M2 differ for each color of color ink.

[0093] In this embodiment, the relative magnitudes of the first allowable ratio R1 and the second allowable ratio R2 are determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35. Here, from the viewpoint of light absorption, the color inks are divided into low-absorption color inks and high-absorption color inks.

[0094] In this embodiment, as shown in Figures 20 and 21, the first pass mask M1 and the second pass mask M2 used when ejecting low-absorption color ink and high-absorption color ink from the nozzle 33 are different. Here, the first pass mask M1 has a first low-absorption pass mask M11 (see Figure 20) used when ejecting low-absorption color ink (here, cyan ink and magenta ink) and a first high-absorption pass mask M12 (see Figure 21) used when ejecting high-absorption color ink (here, yellow ink and black ink). The second pass mask M2 has a second low-absorption pass mask M21 (see Figure 20) used when ejecting low-absorption color ink and a second high-absorption pass mask M22 (see Figure 21) used when ejecting high-absorption color ink.

[0095] In this embodiment, as shown in Figure 21, when comparing the first high-absorption pass mask M12 and the second high-absorption pass mask M22 used when ejecting high-absorption color ink, the second allowable ratio R2 of the second high-absorption pass mask M22 is smaller than the first allowable ratio R1 of the first high-absorption pass mask M12. As shown in Figure 20, when comparing the first low-absorption pass mask M11 and the second low-absorption pass mask M21 used when ejecting low-absorption color ink, the second allowable ratio R2 of the second low-absorption pass mask M21 is larger than the first allowable ratio R1 of the first low-absorption pass mask M11. Here, when comparing the first low-absorption pass mask M11 (see Figure 20) and the first high-absorption pass mask M12 (see Figure 21) used when forming the first ink layer L1, the first allowable ratio R1 is larger for the first high-absorption pass mask M12 than for the first low-absorption pass mask M11. When comparing the second low-absorption pass mask M21 (see Figure 20) and the second high-absorption pass mask M22 (see Figure 21), which are used when forming the second ink layer L2, the second high-absorption pass mask M22 has a smaller second allowable ratio R2 than the second low-absorption pass mask M21.

[0096] In this embodiment, when forming the first ink layer L1 on the workpiece 5, the first ejection control unit 71 in Figure 3 uses a first low-absorption pass mask M11 to control the ejection amount of low-absorption color ink (here, cyan ink and magenta ink) ejected from nozzles 33 included in the first ejection region AR21 of nozzle rows 34C and 34M, as shown in Figure 20, and uses a first high-absorption pass mask M12 to control the ejection amount of high-absorption color ink (here, yellow ink and black ink) ejected from nozzles 33 included in the first ejection region AR21 of nozzle rows 34Y and 34K, as shown in Figure 21. Furthermore, when forming the second ink layer L2 on the first ink layer L1, the second ejection control unit 72 in Figure 3 uses a second low-absorption pass mask M21 to control the amount of low-absorption color ink ejected from the nozzles 33 included in the second ejection region AR22 of nozzle rows 34C and 34M, as shown in Figure 20, and uses a second high-absorption pass mask M22 to control the amount of high-absorption color ink ejected from the nozzles 33 included in the second ejection region AR22 of nozzle rows 34Y and 34K, as shown in Figure 21.

[0097] In this embodiment, as shown in Figures 20 and 21, the first discharge control unit 71 discharges color ink from nozzles 33 included in the first discharge region AR21 of the nozzle row 34 according to the first pass mask M1 to form the first ink layer L1. The second discharge control unit 72 discharges color ink from nozzles 33 included in the second discharge region AR22 of the nozzle row 34 according to a second pass mask M2 different from the first pass mask M1 to form the second ink layer L2. By using different pass masks when forming the first ink layer L1 and when forming the second ink layer L2, it is possible to easily adjust the degree of glossiness in the second ink layer L2.

[0098] In this embodiment, the relationship between the first allowable ratio R1, which is the percentage of color ink discharged in the first pass mask M1, and the second allowable ratio R2, which is the percentage of color ink discharged in the second pass mask M2, differs for each color of color ink. Furthermore, the relationship between the first allowable ratio R1 and the second allowable ratio R2 is determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device 35. In this way, by adjusting the first allowable ratio R1 and the second allowable ratio R2 for each color of color ink, the degree of glossiness in the second ink layer L2 can be adjusted for each color of color ink. Also, as described above, the degree of glossiness may differ depending on the light absorption of the color ink. Therefore, by adjusting the first allowable ratio R1 and the second allowable ratio R2 according to the light absorption of the color ink, the degree of glossiness can be appropriately adjusted.

[0099] In this embodiment, for high-absorption color inks, the second allowable ratio R2 is smaller than the first allowable ratio R1, as shown in Figure 21. For low-absorption color inks, the second allowable ratio R2 is larger than the first allowable ratio R1, as shown in Figure 20. For example, in the case of high-absorption color inks, if the second allowable ratio R2 of the second high-absorption pass mask M22 (see Figure 21) used to form the second ink layer L2 that gives a glossy finish is increased, the amount of high-absorption color ink in the second ink layer L2 increases, which may reduce the degree of gloss. However, in this embodiment, since the second allowable ratio R2 of the second high-absorption pass mask M22 used to form the second ink layer L2 that gives a glossy finish is kept small in high-absorption color inks, the degree of gloss is less likely to decrease.

[0100] In the first and second embodiments, a printing method is implemented. Here, the printing method includes a first ejection step, a second ejection step, and a light irradiation step. The first ejection step is implemented by the first ejection control unit 71. The second ejection step is implemented by the second ejection control unit 72. The light irradiation step is implemented by the light irradiation control unit 73.

[0101] In each of the embodiments described above, matte and glossy printing was switched by changing the elapsed time from when the color ink is ejected and lands on the material to be printed 5 until light is irradiated from the light irradiation device 35. However, the method for switching between matte and glossy printing is not limited to the above. For example, matte and glossy printing may be switched by changing the illuminance of the light irradiated onto the color ink. For example, irradiating the color ink with strong light makes the surface of the ink layer more likely to become matte. For example, irradiating the color ink with weak light makes the surface of the ink layer more likely to become glossy, as the ink is smoothed before it is completely cured.

[0102] In the above embodiments, the light irradiation device 35 was an example of a post-processing device that performs post-processing. That is, in the above embodiments, light was irradiated from the light irradiation device 35 toward the color ink to cure the color ink. However, the post-processing device is not limited to the light irradiation device 35, and may be, for example, a so-called drying device. The drying device is composed of, for example, a heater. For example, the color ink may be dried by heating it with the drying device. For example, the elapsed time from when the color ink is ejected and lands on the substrate 5 until the color ink is heated by the drying device may be changed to switch between matte and glossy printing. For example, if the elapsed time from when the color ink lands until it is heated is short, the surface of the ink layer is more likely to become matte. For example, if the elapsed time from when the color ink lands until it is heated is long, the surface of the ink layer is more likely to become glossy. Also, when a drying device is used as an example of a post-processing device, the heating temperature for heating the color ink may be changed. For example, the higher the heating temperature, the easier it is to make the surface of the ink layer matte. For example, the lower the heating temperature, the easier it is to make the surface of the ink layer glossy.

[0103] 5. Printed material 10, 10A Printer 25. Support stand 32, 32A Ink head 35. Light irradiation device (post-processing device) 60. Control device 71. First ejection control unit 72. Second ejection control unit 73. Light irradiation control unit (post-processing control unit) L1. First ink layer L2. Second ink layer

Claims

1. A printer comprising: a support base for supporting a workpiece; an ink head for ejecting color ink toward the workpiece supported on the support base; a post-processing device for performing post-processing on the color ink ejected toward the workpiece supported on the support base; and a control device, wherein the control device comprises: a first ejection control unit for ejecting color ink from the ink head to form a first ink layer on the workpiece supported on the support base; a second ejection control unit for ejecting color ink from the ink head to form a second ink layer on the first ink layer; and a post-processing control unit for controlling the post-processing device, wherein the post-processing control unit controls the post-processing device so that the surface of the first ink layer becomes matte, and controls the post-processing device so that the surface of the second ink layer becomes glossy.

2. The printer according to claim 1, wherein the first ejection control unit ejects a first amount of color ink to form the first ink layer, and the second ejection control unit ejects a second amount of color ink, which is different from the first amount of color ink, to form the second ink layer.

3. The printer according to claim 2, wherein the ink head is configured to eject a first color ink and a second color ink different from the first color, and the relative amounts of the first ink and the second ink are different.

4. The printer according to claim 2, wherein the post-processing device is a light irradiation device that irradiates light onto the color ink ejected onto the workpiece supported on the support base, and the relative magnitudes of the first ink amount and the second ink amount are determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device.

5. The printer according to claim 4, wherein in the case of a high-absorption color ink, which is a color ink with light absorption higher than a standard value, the amount of the second ink is less than the amount of the first ink, and in the case of a low-absorption color ink, which is a color ink with light absorption lower than the standard value, the amount of the second ink is greater than the amount of the first ink.

6. The printer according to claim 2, wherein the control device includes a storage unit for storing a print image to be printed, and the sum of the first ink amount and the second ink amount is the same as the sum of the ink amounts based on the print image.

7. The printer according to claim 1, wherein the ink head is configured to eject multiple ink dots of different diameters in the color ink, the first ejection control unit ejects color ink such that the distribution of each ink dot size is a first distribution to form the first ink layer, and the second ejection control unit ejects color ink such that the distribution of each ink dot size is a second distribution different from the first distribution to form the second ink layer.

8. The printer according to claim 7, wherein the ink head is configured to eject a first color ink and a second color ink different from the first color, and each of the first color ink and the second color ink is configured to eject a first size ink dot and a second size ink dot with a larger diameter than the first size, and the second size ratio, which is the ratio of the second size ink dots to at least one of the first distribution and the second distribution, is different for the first color ink and the second color ink.

9. The printer according to claim 7, wherein the post-processing device is a light irradiation device that irradiates light onto the color ink ejected onto the workpiece supported on the support base, the ink head is configured to eject ink dots of a first size and ink dots of a second size having a larger diameter than the first size, and the second size ratio, which is the ratio of the second size ink dots to at least one of the first distribution and the second distribution, is determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device.

10. The printer according to claim 9, wherein the second size ratio of the first distribution in the high-absorption color ink, which is a color ink with light absorption higher than a standard value, is greater than the second size ratio of the first distribution in the low-absorption color ink, which is a color ink with light absorption lower than a standard value.

11. The printer according to claim 10, wherein, when the smallest of the multiple sizes of ink dots that the ink head can eject is defined as the minimum size, the proportion of the minimum size ink dot in the first distribution is the same for the high-absorption color ink and the low-absorption color ink.

12. The printer according to claim 7, wherein the second distribution does not include the smallest size ink dot among a plurality of ink dot sizes that the ink head can eject.

13. The printer according to claim 1, wherein the ink head has a nozzle row in which a plurality of nozzles for ejecting color ink are arranged in a predetermined direction, the nozzle row has a first ejection region located on one side of the predetermined direction and a second ejection region located on the other side of the predetermined direction from the first ejection region, the first ejection control unit ejects color ink from the nozzles included in the first ejection region of the nozzle row according to a first pass mask to form the first ink layer, and the second ejection control unit ejects color ink from the nozzles included in the second ejection region of the nozzle row according to a second pass mask different from the first pass mask to form the second ink layer.

14. The printer according to claim 13, wherein the ink head is configured to eject a first color ink and a second color ink different from the first color, and the relationship between a first allowable ratio, which is the ratio of color ink ejection permitted in the first pass mask, and a second allowable ratio, which is the ratio of color ink ejection permitted in the second pass mask, is different for the first color ink and the second color ink.

15. The printer according to claim 14, wherein the post-processing device is a light irradiation device that irradiates light onto the color ink ejected onto the workpiece supported on the support base, and the relationship between the first allowable ratio and the second allowable ratio is determined based on the light absorption of the color ink when light is irradiated onto the color ink from the light irradiation device.

16. The printer according to claim 15, wherein in the case of a high-absorption color ink, which is a color ink with light absorption higher than a standard value, the second allowable ratio is smaller than the first allowable ratio, and in the case of a low-absorption color ink, which is a color ink with light absorption lower than the standard value, the second allowable ratio is larger than the first allowable ratio.

17. A printing method comprising: a first ejection step of ejecting color ink toward a substrate to form a first ink layer on the substrate; a second ejection step of ejecting color ink toward the first ink layer to form a second ink layer on top of the first ink layer; and a post-processing step of performing post-processing on the first ink layer and the second ink layer, wherein the post-processing step is performed so that the surface of the first ink layer becomes matte and the surface of the second ink layer becomes glossy.

18. The printing method according to claim 17, wherein in the first ejection step, a first amount of color ink is ejected to form the first ink layer, and in the second ejection step, a second amount of color ink, which is different from the first amount of ink, is ejected to form the second ink layer.

19. The printing method according to claim 18, wherein in the first ejection step, a plurality of color inks comprising at least a first color ink and a second color ink different from the first color are ejected to form the first ink layer, and in the second ejection step, a color ink comprising at least the first color ink and the second color ink is ejected to form the second ink layer, and the relative amounts of the first ink and the second ink differ between the first color ink and the second color ink.

20. The printing method according to claim 18, wherein, as the post-processing step, light is irradiated toward the first ink layer and the second ink layer, and the relative amounts of the first ink and the second ink are determined based on the light absorption of the color ink when light is irradiated toward the color ink.

Images