Printing apparatus and printing method

Abstract

To properly create printed materials with multiple layers of ink. [Solution] A printing apparatus 12 comprises a head unit 102 which is an ink ejection unit, a moving drive unit 106, and a control unit 110. The moving drive unit 106 causes the head unit 102 to perform the main scanning operation. The head unit 102 has a plurality of first nozzle rows arranged in a first row aligned in the main scanning direction with their positions aligned in the sub-scanning direction, and a second nozzle row arranged in a second row offset from the first row in the sub-scanning direction. The control unit 110 causes the head unit 102 to form a first-row corresponding layer formed using ink ejected from the plurality of first nozzle rows, and a second-row corresponding layer formed using ink ejected from at least one second nozzle row. The first-row corresponding layer is thicker than the second-row corresponding layer, but less than three times the thickness of the second-row corresponding layer.

Description

Technical Field

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

Background Art

[0002] In recent years, printing apparatuses for printing on a medium to be printed have been widely used. Also, regarding the configuration of printed matter created by a printing apparatus, configurations for expressing various designs have been studied (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When using a printing apparatus or the like that performs printing by an inkjet method, for example, a plurality of ink layers can be formed by overlapping them on a medium. And in this case, by forming the ink layers by overlapping them multiple times, for example, a laminate of ink that becomes convex with respect to the surface of the medium can be formed on the medium, and various designs can be expressed. However, when forming a plurality of ink layers by overlapping them with a printing apparatus having a conventional configuration, simply laminating the ink layers may cause various problems. Therefore, an object of the present invention is to provide a printing apparatus and a printing method that can solve the above problems.

Means for Solving the Problems

[0005] The inventors of this application have diligently researched methods for forming multiple layers of ink on a medium. They have found that, regarding problems that can arise when layering many ink layers, for example, when layering inks with different characteristics, separation (dissociation) is likely to occur between those ink layers. More specifically, when forming multiple layers of ink on a medium, for example, it may be desirable to make each ink layer thicker in order to form an ink laminate of a desired height in a short time. In this case, for example, multiple inks for color expression may be used to form the ink layers. For example, a 4C layer may be formed using four inks: yellow (Y), magenta (M), cyan (C), and black (K). In this case, for example, a white layer may be formed on top of the 4C layer, for the purpose of making the colors of the 4C layer less noticeable. Furthermore, in this case, for example, the 4C layer and the white layer will alternately overlap in at least a portion of the ink laminate. The inventors of the present application have found that, when forming an ink laminate with such a configuration, separation between the ink layers is likely to occur, for example, at the interface between the 4C layer and the white layer. The inventors of the present application have also found that, in this case, such separation is particularly likely to occur at the interface where the lower side is the white layer and the upper side is the 4C layer.

[0006] In response to this, the inventors of the present invention have found that one of the causes of such separation is the stacking of ink layers with large differences in thickness. Furthermore, they have found that this separation is particularly likely to occur where a thicker ink layer (upper layer) is stacked on top of a thinner ink layer (lower layer). They have also found that, for example, when alternating layers of relatively thick ink, such as a 4C layer, and relatively thin ink, such as a white layer, the difference in thickness between the ink layers can be reduced to make separation between the ink layers less likely to occur. In this case, the thickness of the relatively thick ink layer can be made, for example, less than three times the thickness of the relatively thin ink layer. With this configuration, for example, printed materials with multiple ink layers can be produced more appropriately.

[0007] Furthermore, the inventors of this application, through further diligent research, have discovered the features necessary to obtain such effects, leading to the present invention. In order to solve the above problems, the present invention provides a printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, comprising: an ink ejection unit having a nozzle row in which nozzles for ejecting ink onto the medium are arranged; a movement drive unit that causes the ink ejection unit to perform a movement operation relative to the medium; and a control unit that controls the operation of the ink ejection unit and the movement drive unit, wherein the movement drive unit causes the ink ejection unit to perform a main scanning operation in which it ejects ink while moving relative to the medium in a preset main scanning direction, and the ink ejection unit has a plurality of nozzle rows, wherein the plurality of nozzle rows consist of a plurality of first nozzle rows which are arranged in a first row that is aligned in the main scanning direction with their positions aligned in a sub-scanning direction perpendicular to the main scanning direction, and a second row which is arranged in a position shifted from the first row in the sub-scanning direction. The device has at least one second nozzle row which is a nozzle row, and the control unit controls the operation of the ink ejection unit and the moving drive unit to cause the ink ejection unit to form a first row corresponding layer which is a layer of ink formed using the ink ejected from the plurality of first nozzle rows, and a second row corresponding layer which is a layer of ink formed using the ink ejected from at least one second nozzle row, and the number of first nozzle rows used to form the first row corresponding layer is defined as the number of nozzle rows when the first row corresponding layer is formed, and the number of second nozzle rows used to form the second row corresponding layer is defined as the number of nozzle rows when the second row corresponding layer is formed, in which case the number of nozzle rows when the first row corresponding layer is formed is greater than the number of nozzle rows when the second row corresponding layer is formed, and the control unit causes the ink ejection unit to form a first row corresponding layer which is thicker than the second row corresponding layer and less than three times the thickness of the second row corresponding layer.

[0008] With this configuration, by forming the first-row corresponding layer using ink ejected from multiple first-row nozzles, for example, a first-row corresponding layer with considerable thickness can be appropriately formed. Furthermore, this allows for an appropriate increase in the height of the ink laminate formed by stacking multiple ink layers in a short amount of time. Also, in this case, by forming the second-row corresponding layer using ink ejected from the second-row nozzles, for example, a layer of ink with different characteristics from the first-row corresponding layer can be appropriately formed. Therefore, with this configuration, for example, an ink laminate in which layers of ink with different characteristics overlap can be appropriately formed. Also, in this case, by making the thickness of the first-row corresponding layer less than three times the thickness of the second-row corresponding layer, for example, the difference in thickness between the stacked ink layers can be appropriately reduced. Furthermore, this makes it less likely for separation to occur between the ink layers. Therefore, with this configuration, for example, printed materials with multiple ink layers can be appropriately created.

[0009] In this configuration, the thickness of the first-row corresponding layer is preferably 1.5 times or more the thickness of the second-row corresponding layer. With this configuration, for example, a first-row corresponding layer with a large thickness can be appropriately used. It is more preferable that the thickness of the first-row corresponding layer is 1.7 times or more the thickness of the second-row corresponding layer. It is also more preferable that the thickness of the first-row corresponding layer is less than 2.5 times the thickness of the second-row corresponding layer. The first nozzle row ejects colored inks of different colors, for example, which are the basic colors for color expression. In this case, for example, yellow (Y), magenta (M), cyan (C), and black (K) can be used as the basic colors for color expression. In this case, for example, a 4C layer, which is a layer of ink formed using these four colors, can be formed as the first-row corresponding layer. With this configuration, for example, a first-row corresponding layer with a large thickness can be appropriately formed. The ink ejection section also has, for example, at least a nozzle row that ejects light-reflective ink as the second nozzle row. The control unit then causes the ink ejection unit to form a second-row corresponding layer using at least a light-reflective ink. In this case, the ink ejection unit forms a light-reflective layer, which is a layer of light-reflective ink, as the second-row corresponding layer. The ink ejection unit also forms the light-reflective layer on top of the first-row corresponding layer by alternately forming the first-row corresponding layer, such as a 4C layer, and the light-reflective layer. With this configuration, for example, the color of the first-row corresponding layer can be appropriately prevented from being conspicuous. In this case, the light-reflective layer that overlaps the first-row corresponding layer can also be considered to function as an opacity layer that hides the color of the first-row corresponding layer. As the light-reflective ink, for example, white ink can be suitably used. Furthermore, as described above, in this configuration, the ink ejection unit forms the first-row corresponding layer, such as a 4C layer, and the second-row corresponding layer, such as a light-reflective layer, by alternately overlapping them. In this case, the control unit can be configured such that, for example, multiple first-row corresponding layers are formed in the ink ejection unit, and at least some of the first-row corresponding layers are formed in the ink ejection unit so as to be in contact with the second-row corresponding layer and overlapping the second-row corresponding layer. With this configuration, for example, the first-row corresponding layers and the second-row corresponding layers can be appropriately formed in the ink ejection unit.Furthermore, in this case, at least some of the first-column corresponding layers can be considered to overlap, for example, with the second-column corresponding layer.

[0010] Furthermore, in this configuration, the ink ejection unit may have multiple second nozzle rows. In this case, by forming a second-row corresponding layer using ink ejected from multiple second nozzle rows, a second-row corresponding layer that is thicker than, for example, an ink layer formed using only one second nozzle row can be appropriately formed. This also makes it possible to appropriately form a second-row corresponding layer with a small difference in thickness from the first-row corresponding layer. As for the multiple second nozzle rows, for example, it is conceivable to use multiple nozzle rows that eject inks of different colors. In this case, with respect to the multiple second nozzle rows used to form the second-row corresponding layer, it is conceivable to use, for example, a nozzle row that ejects light-reflective ink as one of the second nozzle rows. And, for example, it is conceivable to use a nozzle row that ejects inks other than light-reflective ink as the other second nozzle rows. In this case, as the inks other than light-reflective ink, for example, colorless ink can be used. With this configuration, for example, a layer of light-reflective ink that has opacity to the color of the first-row corresponding layer can be appropriately formed as the second-row corresponding layer, while also using inks other than light-reflective inks.

[0011] Furthermore, as described above, white ink can be suitably used as the light-reflective ink. However, with respect to the ink layer formed using white ink, separation from other ink layers may easily occur due to the influence of pigments contained in the ink. In contrast, with the above configuration, by forming a second-row corresponding layer using an ink other than the light-reflective ink, separation between ink layers can be made less likely compared to, for example, the case where only white ink is used to form the second-row corresponding layer. Furthermore, regarding the ink used to form the second-row corresponding layer, an adhesive ink with higher adhesion to the medium than the light-reflective ink can be suitably used as an ink other than the light-reflective ink. In this case, the ink ejection unit can be considered to have, for example, a second nozzle row that ejects adhesive ink. In this case, the control unit can, for example, cause the ink ejection unit to form the second-row corresponding layer using the light-reflective ink and the adhesive ink. With this configuration, a layer of ink with high adhesion to other ink layers can be formed as the second-row corresponding layer. Furthermore, this makes it less likely for separation to occur between ink layers, for example. Suitable adhesive inks include, for example, primer inks.

[0012] Furthermore, when forming multiple layers of ink, various problems can arise in addition to separation between the ink layers. For example, when forming an ink laminate on a medium using UV-curing inks, it may be desirable to cure the ink dots in the top layer of the laminate to a glossy finish. For instance, when forming a clear layer on the top surface of an ink laminate using clear ink, it may be desirable to cure the ink dots to a glossy finish to enhance glossiness. However, when forming a clear layer on top of multiple ink layers that have already been formed, it can be difficult to properly form a clear layer cured under glossy conditions. More specifically, for example, if one attempts to form a clear layer under glossy conditions on top of multiple ink layers that have already been formed, the clear layer may appear eroded near the edges of the ink layers. It can also be assumed that similar problems occur when forming ink layers other than the clear layer under glossy conditions.

[0013] In contrast, the inventors of the present invention have found that by curing the ink layer formed beneath the ink layer cured under glossy conditions under matte conditions, the formation of the glossy ink layer can be more appropriately achieved. In this case, the ink layer formed beneath the ink layer formed under glossy conditions can be considered, for example, as an ink layer in which the ink dots are not flattened (leveled). Furthermore, in this case, the present invention can be considered to be a printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, comprising an ink ejection unit for ejecting ink onto the medium and a control unit for controlling the operation of the ink ejection unit, wherein the ink ejection unit has an ejection head for ejecting ultraviolet-curable ink and an ultraviolet light source for irradiating ultraviolet light to cure the ultraviolet-curable ink, and the control unit causes the ink ejection unit to form raised portions that become convex on the surface of the medium due to the overlapping of multiple layers of ink on the medium, a matte layer which is formed by irradiating ultraviolet light from the ultraviolet light source under conditions to cure the ink dots into a matte state, and a gloss layer which is formed by irradiating ultraviolet light from the ultraviolet light source under conditions to cure the ink dots into a glossy state.

[0014] With this configuration, for example, when performing printing that involves layering ink multiple times, a gloss layer can be appropriately formed on the raised portion. For the gloss layer, for example, a layer of clear ink can be formed. For the matte layer, for example, a layer of clear ink can be formed. Alternatively, a layer of ink other than clear ink can be formed as the matte layer. In this case, for example, a white layer formed with white ink or a color layer colored using process color inks can be formed as the matte layer. Alternatively, a layer of ink other than clear ink can be formed as the gloss layer. Furthermore, for example, the matte layer covering the raised portion can be formed over a wider area than the raised portion. In this case, the control unit causes the ink ejection unit to form a matte layer over a wider area than the raised portion, for example, so that the matte layer covers the entire raised portion. With this configuration, for example, a matte layer covering the entire raised portion can be appropriately formed. Furthermore, the control unit may cause the ink ejection unit to form a gloss layer over a wider area than the matte layer, for example, so that the gloss layer covers the entire matte layer. With this configuration, for example, a gloss layer that covers the entire raised portion can be appropriately formed. In this case, the gloss layer may cover at least a part of the medium around the raised portion. Such a gloss layer can be considered, for example, as a layer that covers at least a part of the medium together with the raised portion. With this configuration, for example, a design in which the entire raised portion is covered with a glossy layer can be appropriately expressed. Also, in this case, the matte layer can also be formed, for example, so that it covers at least a part of the medium together with the raised portion. With this configuration, for example, a matte layer and a gloss layer that cover the raised portion can be appropriately formed.

[0015] Furthermore, when forming multiple layers of ink, problems such as those related to the bulging that occurs at the edges of the ink layers can be considered. More specifically, when forming layers of ink, for example, bulging may occur at the contour portion, which is the edge of the ink layer, due to the influence of the surface tension of the ink. In this regard, if only one layer of ink is formed, such bulging is usually not considered a problem. However, when forming multiple layers of ink, the overlapping of these bulging portions can have a significant impact on the shape of the ink laminate. In response to this, the inventors of the present invention have found that by using an inkjet head with a variable ink discharge capacity in multiple stages, and by forming at least some of the ink dots formed at the contour portion with an ink discharge capacity less than the maximum capacity, such problems can be made less likely to occur. Furthermore, in this case, the present invention can be considered as a printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, comprising an ink ejection unit for ejecting ink onto the medium, and a control unit for controlling the operation of the ink ejection unit, wherein the ink ejection unit has an inkjet head that ejects ink in an inkjet manner, the ink ejection head has a variable ink ejection capacity in multiple stages, and the ratio of the ejection position where ink is ejected at the maximum capacity among the multiple ink capacities to the ink ejection position per unit area is defined as the maximum capacity ejection position ratio, and with respect to the ink layers to be formed by the ink ejection unit, a part of the range including the outermost periphery of the ink layer is defined as the contour portion, and the part of the ink layer inside the contour portion is defined as the inner circumference portion, and at least when forming a part of the ink layer, the control unit causes the inkjet head to eject ink such that the maximum capacity ejection position ratio in the contour portion is smaller than the maximum capacity ejection position ratio in the inner circumference portion.

[0016] With this configuration, for example, it is possible to appropriately prevent the formation of large raised areas around the contours of the ink layers. Furthermore, this allows for the more appropriate stacking and formation of multiple ink layers. In addition, it is preferable for the control unit to cause the inkjet head to eject ink such that, for more than half of the stacked ink layers, the ratio of maximum capacity ejection positions at the contours is smaller than the ratio of maximum capacity ejection positions at the inner circumference. With this configuration, for example, it is possible to more appropriately stack and form multiple ink layers. It is even more preferable for the control unit to set the ratio of maximum capacity ejection positions as described above for all stacked ink layers. Furthermore, to more reliably prevent raised areas around the contours, it is preferable for the control unit to, for example, not cause the inkjet head to eject at maximum capacity to the contours of the ink layers. In this case, the ink dots formed around the contours can be considered, for example, ink dots formed by ejecting ink at capacities other than the maximum capacity. In this case, at least when forming some of the ink layers, the control unit causes the inkjet head to eject ink at a capacity less than the maximum capacity at all ejection positions where ink is ejected around the contours. With this configuration, for example, multiple layers of ink can be formed more appropriately. Furthermore, as a configuration of the present invention, for example, a printing method configuration having the same characteristics as described above can also be considered. In this case as well, for example, the same effects as described above can be obtained. [Effects of the Invention]

[0017] According to the present invention, for example, printed materials with multiple layers of ink can be appropriately created. [Brief explanation of the drawing]

[0018] [Figure 1] This figure illustrates a printing system 10 according to one embodiment of the present invention. Figure 1(a) shows an example of the configuration of the printing system 10. Figure 1(b) shows an example of the configuration of the printing device 12 in the printing system 10. Figure 1(c) shows an example of the configuration of the head unit 102 in the printing device 12. [Figure 2] This figure provides a more detailed explanation of the printed material, which is the output of printing produced by the printing device 12. Figure 2(a) shows an example of the structure of the printed material produced by the printing device 12. Figure 2(b) shows an example of the structure of the lower laminate 52 in the ink laminate. Figure 2(c) shows an example of how the WPr layer 164 is formed in the lower laminate 52. [Figure 3] This diagram illustrates a modified example of the operation of the printing device 12. [Figure 4] This figure illustrates further variations in the operation of the printing apparatus 12. Figure 4(a) shows an example of the configuration of an ink laminate having a raised portion 62 and an overcoat portion 64. Figures 4(b) and (c) show examples of the configuration of the ink laminate formed in this modified example. [Modes for carrying out the invention]

[0019] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a diagram illustrating a printing system 10 according to one embodiment of the present invention. Figure 1(a) shows an example of the configuration of the printing system 10. Figure 1(b) shows an example of the configuration of the printing device 12 in the printing system 10. Figure 1(c) shows an example of the configuration of the head unit 102 in the printing device 12. Except for the points described below, the printing system 10 and each part of the printing system 10 may have the same or similar characteristics as known printing systems and each part thereof. In this example, the printing system 10 is a system that performs printing by forming layers of ink on a medium 50 to be printed on, and comprises a printing device 12 and a control device 14. The printing device 12 is the device that performs printing in the printing system 10. In this example, the printing device 12 is an inkjet printer that performs printing using an inkjet method, and performs printing by ejecting ink onto the medium 50 to form multiple layers of ink. In this way, the printing device 12 forms a stack of ink on the medium 50 that is convex on the surface of the medium 50.

[0020] In this example, the printing apparatus 12 includes, for example, a head unit 102, a base unit 104, a moving drive unit 106, and a control unit 110, as shown in Figure 1(b). The head unit 102 is an example of an ink ejection unit that ejects ink onto the medium 50, and includes, for example, a plurality of inkjet heads 202 and a plurality of ultraviolet light sources 204, as shown in Figure 1(c). In this example, the head unit 102 includes, as a plurality of inkjet heads 202, inkjet heads 202 for each process color and inkjet heads 202 for predetermined spot colors. More specifically, in this example, the head unit 102 includes, as inkjet heads 202 for each process color, inkjet heads 202 for yellow (Y), magenta (M), cyan (C), and black (K). Furthermore, the head unit 102 has an inkjet head 202 for spot colors, which includes inkjet heads 202 for white (W) ink, clear ink (CL), and primer ink (Pr). In this case, process colors can be considered, for example, as basic colors for color expression. Process colors can also be considered, for example, as basic colors used for color expression using the subtractive color mixing method in color printing performed by the printing device 12. Process color inks can also be considered, for example, as colored inks used as basic colors for color expression. Spot colors can be considered, for example, as inks of a different color from the process color inks. In this example, white ink is an example of a light-reflective ink. Clear ink is a colorless and transparent ink. Regarding the clear ink, the fact that it is colorless and transparent can be considered, for example, as intentionally not having any colorants added. Primer ink is an ink for forming a primer layer, which is a base ink layer, on the medium 50. In this example, primer ink is an example of an adhesive ink. Adhesive inks can be considered, for example, inks that have higher adhesion to the medium 50 compared to other inks used in the printing apparatus 12. In this example, the primer ink can be considered, for example, an ink that has higher adhesion to the medium 50 than at least white ink.

[0021] Also, in this example, the inkjet head 202 is an example of a discharge head that discharges ink, and discharges ultraviolet-curable ink (UV ink), which is ink cured by irradiation with ultraviolet rays, by an inkjet method. Further, the inkjet head 202 has a nozzle row in which a plurality of nozzles are arranged with their positions in a predetermined sub-scanning direction (X direction in the figure) preset in the printing apparatus 12 being different from each other. Among the plurality of inkjet heads 202 in the head unit 102, the inkjet heads 202 for each color of process color, for example, as shown in the figure, are arranged side by side in the main scanning direction (Y direction in the figure) orthogonal to the sub-scanning direction with their positions in the sub-scanning direction aligned. Also, the plurality of inkjet heads 202 for special features are arranged side by side in the main scanning direction with their positions in the sub-scanning direction aligned at positions shifted from the inkjet heads 202 for process color in the sub-scanning direction. In a modification of the configuration of the head unit 102, the inkjet heads 202 for special features may be arranged, for example, with their positions in the sub-scanning direction aligned with the inkjet heads 202 for process color. The head unit 102 may have inkjet heads 202 for other colors than those described above. Also, in this example, the head unit 102 has a plurality of nozzle rows that discharge inks of different colors by having a plurality of inkjet heads 202. As the inkjet head 202, for example, a configuration having a plurality of nozzle rows that discharge inks of different colors may also be considered. In this case, the head unit 102 may have a plurality of nozzles by having such an inkjet head 202. Also, in this case, regarding the inkjet head 202 having a plurality of nozzles, for example, a configuration that also serves as a plurality of inkjet heads that discharge inks of different colors can also be considered.

[0022] Also, in this example, the plurality of nozzle arrays corresponding to the plurality of inkjet heads 202 for process colors are an example of the plurality of first nozzle arrays. And the plurality of nozzle arrays corresponding to the inkjet heads 202 for white ink, clear ink, and primer ink are an example of the plurality of second nozzle arrays. In this case, regarding the plurality of first nozzle arrays, for example, they can be considered as a plurality of nozzle arrays arranged in a first row that is a row aligned in the main scanning direction with their positions in the sub-scanning direction aligned. Regarding the second nozzle arrays, for example, they can be considered as nozzle arrays arranged in a second row that is a row with its position in the sub-scanning direction shifted from the first row. In this case, regarding the arrangement of the nozzle arrays, regarding the alignment of positions in the sub-scanning direction and arrangement in the main scanning direction, for example, it can be considered that they are substantially aligned according to the accuracy required for printing, etc. Also, regarding the alignment of positions in the sub-scanning direction and arrangement in the main scanning direction, for example, it can also be considered that when judged visually by the user, it can be judged that the nozzle arrays are arranged substantially in this way. Regarding the second nozzle arrays, for example, they can also be considered as nozzle arrays of the inkjet heads 202 that are stagger - arranged with respect to the inkjet heads 202 having the first nozzle arrays. Also, in the head unit 102, the plurality of ultraviolet light sources 204 are light sources that irradiate ultraviolet light for curing ultraviolet - curable ink. In this example, the ultraviolet light sources 204 are arranged on one side and the other side in the main scanning direction with respect to the plurality of inkjet heads 202.

[0023] The base portion 104 is an example of a media holding portion, and supports the media 50 at a position opposite the head portion 102 by holding the media 50 on an opposing surface which is the surface facing the head portion 102. In this case, the opposing surface can be considered as, for example, the top surface of the base portion 104. As the base portion 104, for example, a table-shaped member that holds the entire media 50 on its top surface can be suitably used. In this case, the printing device 12 can be considered as, for example, a flatbed type inkjet printer that prints on a media 50 in a fixed position. Alternatively, as the base portion 104, for example, a table-shaped member that supports only a part of the media 50 can be used. In this case, the base portion 104 can be considered as, for example, holding the media 50 on the opposing surface by supporting a part of the media 50. Also in this case, the printing device 12 can be considered as, for example, a vertical type inkjet printer that prints on the media 50 while transporting it.

[0024] The moving drive unit 106 is a drive unit that causes the head unit 102 to perform a moving operation relative to the medium 50. In this case, causing the head unit 102 to perform a moving operation can be thought of as, for example, causing the inkjet head 202 in the head unit 102 to perform a moving operation. In this example, the moving drive unit 106 causes the head unit 102 to perform a main scanning operation, a sub-scanning operation, and stacking direction movement as moving operations. The main scanning operation can be thought of as, for example, an operation in which ink is ejected while moving in the main scanning direction relative to the medium 50 (scanning operation). The sub-scanning operation can be thought of as, for example, an operation in which the head unit 102 moves in the sub-scanning direction relative to the medium 50. The moving drive unit 106 causes the head unit 102 to perform a sub-scanning operation in between main scanning operations, thereby changing the portion of the medium 50 that is facing the head unit 102 in each main scanning operation. The sub-scanning operation can be thought of as, for example, a feeding operation (feed operation) that moves the medium 50 to the head unit 102. The moving drive unit 106 causes the head unit 102 to perform a main scanning operation and a sub-scanning operation, thereby moving the head unit 102 relative to the medium 50 and ejecting ink from the head unit 102. In addition, the moving drive unit 106 causes the head unit 102 to perform an operation that forms an ink layer on the medium 50.

[0025] In this example, the moving drive unit 106 causes the head unit 102 to repeatedly perform the operation of forming ink layers, thereby forming multiple layers of ink on the head unit 102. In this case, the moving drive unit 106 causes the head unit 102 to move in the stacking direction with respect to at least some of the ink layers, after the formation of that ink layer and before the formation of the next ink layer begins. The stacking direction movement can be thought of as, for example, an operation in which the head unit 102 moves relative to the medium 50 in the stacking direction (Z direction in the figure), which is the direction in which multiple ink layers overlap. In this example, the stacking direction is a direction perpendicular to the main scanning direction and the sub-scanning direction. The moving drive unit 106 moves the head unit 102 in the stacking direction relative to the medium 50 by moving at least one of the head unit 102 and the base unit 104 such that the distance between the opposing surface (upper surface) of the base unit 104 and the head unit 102 changes in the stacking direction. In this case, the moving drive unit 106 causes the head unit 102 to move in the stacking direction, for example, by raising the head unit 102 or lowering the base unit 104, so that the head gap, which is the distance between the inkjet head 202 and the media 50 in the head unit 102, widens. With this configuration, for example, the head gap can be appropriately adjusted to match the height (thickness) of the ink layers stacked on the media 50. This also allows for the appropriate formation of multiple ink layers on the media 50. The control unit 110 includes, for example, the CPU of the printing device 12 and controls the operation of each part of the printing device 12. In this example, the control unit 110 receives print data generated by the control device 14 from the control device 14 and controls the operation of each part of the printing device 12 based on this print data. In this case, the control unit 110 controls the operation of the head unit 102 and the moving drive unit 106 based on the print data, for example, so that the inkjet head 202 in the head unit 102 is irradiated with ultraviolet light and the head unit 102 performs the main scanning operation. Furthermore, the control unit 110 causes the head unit 102 to perform a main scanning operation while performing a sub-scanning operation as needed, thereby forming an ink layer on the head unit 102.Furthermore, the control unit 110 controls the operation of the head unit 102 and the moving drive unit 106, for example, causing the head unit 102 to move in the stacking direction as needed, and forming multiple ink layers on the head unit 102. According to this example, for example, multiple ink layers can be appropriately formed on the medium 50.

[0026] Furthermore, the control device 14 is a device that controls the operation of the printing device 12, and controls the operation of the printing device 12 by supplying print data to the printing device 12.In this example, the control device 14 is a computer such as a PC that executes a program for generating print data, and controls the operation of the printing device 12 by supplying the print data generated according to this program to the printing device 12.In this example, the control device 14 supplies print data to the printing device 12 that specifies a printing operation in which multiple layers of ink are layered to form a laminate of ink on the medium 50, causing the printing device 12 to perform the operation of forming a laminate of ink on the medium 50.In this case, the print data that the control device 14 supplies to the printing device 12 can be, for example, print data for 2.5D printing that forms a convex shape on the medium 50.In this case, the printing device 12 forms a laminate of ink on the medium 50 with the configuration shown in Figure 2, for example, based on the print data.

[0027] Figure 2 is a diagram that further explains the printed material, which is the output of printing produced by the printing apparatus 12. Figure 2(a) shows an example of the structure of the printed material produced by the printing apparatus 12. Figure 2(b) shows an example of the structure of the lower laminated portion 52 in the ink laminate formed on the medium 50. Figure 2(c) shows an example of how the WPr layer 164 is formed in the lower laminated portion 52. In this example, the printing apparatus 12 forms an ink laminate on the medium 50, including, for example, a lower laminated portion 52 and an upper decorative portion 54, by stacking multiple layers of ink. In this case, the lower laminated portion 52 is a raised portion formed by stacking multiple layers of ink on the medium 50. The lower laminated portion 52 can also be thought of as, for example, a thick layer of ink stacked on top of each other. The lower laminated portion 52 can also be thought of as, for example, the part of the ink laminate formed on the medium 50 other than the uppermost decorative portion 54. Furthermore, in this example, the head unit 102 (see Figure 1) of the printing apparatus 12 forms a lower laminated section 52 with a configuration in which 4C layers 162 and WPr layers 164 are alternately stacked, as shown in Figure 2(b), for example. In this case, the lower laminated section 52 can also be considered as a layer having, for example, multiple 4C layers 162 and multiple WPr layers 164. The 4C layer 162 is an ink layer formed using four inks of YMCK (CMYK), which are the colors of process colors. In this case, the 4C layer 162 can also be considered as an ink layer formed using four nozzle rows corresponding to four inkjet heads 202 (see Figure 1). In this example, the 4C layer 162 can also be considered as an ink layer formed by ink ejected from multiple nozzle rows aligned in the main scanning direction with their positions aligned in the sub-scanning direction.

[0028] Furthermore, the moving drive unit 106 (see Figure 1) causes the head unit 102 to perform a main scanning operation while uniformly ejecting ink to multiple inkjet heads 202 (four inkjet heads 202 for YMCK), thereby uniformly mixing the ink ejected from the multiple inkjet heads 202 and forming a 4C layer 162 on the multiple inkjet heads 202. In this case, uniformly mixing the ink ejected from the multiple inkjet heads 202 can be considered by setting the amount of ink ejected per unit area to the same amount and ejecting ink to the multiple inkjet heads 202. Also, when forming the 4C layer 162, the moving drive unit 106 causes each inkjet head 202 to eject ink at the density of solid printing. Discharging ink at the density of solid printing to the inkjet heads 202 can be considered by discharging ink at the density of solid printing to the nozzle row used for forming the ink layer in the inkjet head 202, for example. In this case, the moving drive unit 106, for example, in response to the control unit 110, causes the inkjet head 202 to eject ink at the ink ejection positions included in the area where the 4C layer 162 should be formed. By forming the 4C layer 162 in this way, it is possible to appropriately form a 4C layer 162 that is thicker than, for example, an ink layer formed by only one inkjet head 202. In this case, by stacking the thick 4C layer 162 with a WPr layer 164 in between to form the lower laminated section 52, for example, the lower laminated section 52 can be formed appropriately in a short time. Furthermore, this makes it possible to appropriately increase the height of the ink laminate formed by stacking multiple ink layers in a short time. The density of solid printing can be considered as, for example, a density that is set to fill with a predetermined density of 100%. More specifically, as the density of solid printing, for example, it is conceivable to use a density that ejects ink to all ejection positions set according to the printing resolution within the range in which the ink layer is formed. Furthermore, the inkjet head 202 could also be configured to have a variable ink ejection capacity in multiple stages.In this case, when forming the 4C layer 162, the inkjet head 202 ejects, for example, the maximum capacity of ink to the ejection position. More specifically, for example, when using an inkjet head 202 that can change the ink capacity in three stages: large (L), medium (M), and small (S), when forming the 4C layer 162, the inkjet head 202 ejects, for example, the large capacity of ink to the ejection position. With this configuration, for example, a 4C layer 162 with a large thickness can be formed more appropriately.

[0029] Furthermore, among the ink layers contained in the lower laminated section 52, the WPr layer 164 is an ink layer formed using white ink and primer ink. In this example, the moving drive unit 106 causes the inkjet head 202 for the white ink to eject white ink and the inkjet head 202 for the primer ink to eject primer ink, thereby forming the WPr layer 164 on the head section 102. In this case, the moving drive unit 106, for example, causes each of the inkjet heads 202 used to form the WPr layer 164 to eject ink at the density of solid printing. Also, in this example, the WPr layer 164, formed using white ink, for example, becomes a light-reflective ink layer (light-reflective layer). In this case, the WPr layer 164 that overlaps with the 4C layer 162 can be considered to function as an opacity layer that hides the color of the 4C layer 162. By forming the lower laminated section 52 having such a WPr layer 164, it is possible to appropriately prevent, for example, the color of the 4C layer 162 from being excessively prominent in the finished printed material. Furthermore, this also appropriately prevents, for example, a decrease in the quality of the printed material due to the influence of the color of the 4C layer 162. In this example, the WPr layer 164 can be considered, for example, as a layer of ink with different characteristics from the 4C layer 162. In this case, the ink laminate including the lower laminated section 52 can be considered to have a configuration in which layers of ink with different characteristics overlap. Moreover, in this example, by forming such a WPr layer 164, it is possible to make, for example, separation between ink layers in the lower laminated section 52 less likely to occur. Matters concerning the separation between ink layers in the lower laminated section 52 will be explained in more detail later.

[0030] Furthermore, the upper decorative layer 54 is a portion formed for decoration at the top of the ink laminate. The upper decorative layer 54 can be considered, for example, as a portion composed of an ink layer for expressing a design that is visible to the observer. Alternatively, the upper decorative layer 54 can be considered, for example, as a portion composed of an ink layer formed on top of the lower laminate 52. In this example, the upper decorative layer 54 has a white layer 152 and a color layer 154. The white layer 152 is an ink layer formed with white ink ejected from the inkjet head 202 for white ink. In this example, the moving drive unit 106 causes the inkjet head 202 for white ink to eject ink at a density suitable for solid printing, for example, to form the white layer 152 on the head unit 102. The white layer 152 can also be considered, for example, as a light-reflecting layer formed with light-reflecting ink. Furthermore, in this example, the white layer 152 is formed between the lower laminated section 52 and the color layer 154, so that it functions as an opacity layer that hides the color of the lower laminated section 52, for example, while also functioning as a background for the color layer 154. In this case, by forming the color layer 154 on top of the white layer 152, the influence of the color of the lower laminated section 52 can be suppressed more reliably, for example, while allowing the color expressed by the color layer 154 to be appropriately perceived by the observer.

[0031] Furthermore, in this example, the color layer 154 is a layer of ink that is colored using at least process color inks. In this case, with respect to the color layer 154, the use of at least process color inks can be considered as, for example, the color layer 154 being colored using ink of a color that matches the design to be expressed in the color layer 154. When the color layer 154 is formed, the inkjet heads 202 for each process color eject ink to, for example, ejection positions selected according to the design to be expressed from among the ejection positions set in the printing resolution. With this configuration, for example, the design that is visible to the observer can be appropriately expressed in the upper decorative layer 54. In this case, the head unit 102 forms the color layer 154 such that, for example, a color image matching the design to be expressed in the upper decorative layer 54 is drawn. Also, as explained above, in this example, the lower laminated layer 52 formed below the upper decorative layer 54 has a WPr layer 164. In this case, depending on the design and quality required for the printed material, for example, the white layer 152 in the upper decorative layer 54 may be omitted by forming a WPr layer 164 on the top of the upper decorative layer 54.

[0032] Here, we will explain in more detail the separation of ink layers in the lower laminated section 52. As explained above, in this example, the lower laminated section 52 has a 4C layer 162 and a WPr layer 164. In this regard, if we only consider concealing the color of the 4C layer 162 in the lower laminated section 52, it might seem that the ink layer to be superimposed on the 4C layer 162 could be formed using only white ink, for example. However, when forming the ink layer using the head section 102 with the configuration shown in Figure 1(c), if the ink layer is formed using only white ink, an ink layer with a large difference in thickness from the 4C layer 162 will be formed. More specifically, as explained above, in this example, the 4C layer 162 is an ink layer formed using four nozzle rows corresponding to four inkjet heads 202. Also, when forming the 4C layer 162, the moving drive unit 106 ejects ink at a density equivalent to solid printing to each inkjet head 202, for example. In contrast, when forming an ink layer using only white ink, that ink layer is formed using only one set of nozzles corresponding to the white inkjet head 202. Therefore, in this case, the thickness of this ink layer will be about one-quarter that of the 4C layer 162, and the difference in thickness between the two layers will be significant. In this case, differences in expansion and contraction in response to temperature changes, for example, may make separation between the ink layers more likely. Furthermore, the inventors of this application have confirmed through experiments that in a configuration in which white ink layers and 4C layers 162 are stacked alternately, separation between the ink layers is more likely to occur compared to, for example, when only 4C layers 162 are stacked. They also found that this separation is particularly likely to occur at the interface where the thin ink layer is on the bottom and the 4C layer 162 is on the top. In addition, for ink layers formed using white ink, it is also possible that separation between other ink layers may be more likely due to the influence of pigments contained in the ink.

[0033] In contrast, in this example, the lower laminated section 52 has a WPr layer 164 as an ink layer to be layered with the 4C layer 162. In this case, by forming the WPr layer 164 using a primer ink in addition to white ink, it is possible to appropriately form an ink layer that is thicker than, for example, an ink layer formed with only white ink. Furthermore, this makes it possible to appropriately reduce the difference in thickness between the overlapping ink layers in the lower laminated section 52. Therefore, with this configuration, separation between ink layers in the lower laminated section 52 becomes less likely. Also, in this case, by using an ink other than white ink in combination to form the ink layer, it becomes possible to reduce the influence of the pigment contained in the white ink, for example. Therefore, according to this example, it is possible to use white ink when forming the ink layer to be layered with the 4C layer 162, while making it less likely to separate between ink layers. Moreover, in this example, the ink other than white ink used when forming the WPr layer 164 is a primer ink that has higher adhesion to other ink layers and media than white ink. In this case, it is also possible to form, for example, a layer of ink with high adhesion to the 4C layer 162 as the WPr layer 164. Therefore, in this example as well, it is possible to make separation between the ink layers in the lower laminated portion 52 less likely to occur.

[0034] Furthermore, as explained above, the multiple nozzle rows for process color used to form the 4C layer 162 are an example of multiple first nozzle rows. The nozzle rows for white ink and primer ink used to form the WPr layer 164 are an example of second nozzle rows. In this case, the 4C layer 162 can be considered, for example, an example of a first-row corresponding layer, which is an ink layer corresponding to the first nozzle row. Similarly, the WPr layer 164 can be considered, for example, an example of a second-row corresponding layer, which is an ink layer corresponding to the second nozzle row. The first-row corresponding layer can be considered, for example, an ink layer formed using ink ejected from multiple first nozzle rows. The second-row corresponding layer can be considered, for example, an ink layer formed using ink ejected from at least one second nozzle row. In this example, the control unit 110 (see Figure 1) of the printing apparatus 12 controls the operation of the head unit 102 and the moving drive unit 106 to form the 4C layer 162 and the WPr layer 164, which are examples of the first and second column corresponding layers, on the head unit 102.

[0035] Furthermore, regarding the nozzle rows used when forming the 4C layer 162 and the WPr layer 164, as explained above, in this example, the head unit 102 has ultraviolet light sources 204 (see Figure 1) on one side and the other side of the main scanning direction relative to the multiple inkjet heads 202. The control unit 110 controls the operation of the head unit 102 and the moving drive unit 106, for example, by irradiating the ultraviolet light source 204 with ultraviolet light while causing the head unit 102 to perform the main scanning operation. In this case, the nozzle rows used to form one ink layer are usually selected from nozzle rows that are aligned in the main scanning direction and positioned in the sub-scanning direction. Therefore, when using the head unit 102 with the configuration shown in Figure 1(c), the 4C layer 162 can be considered to be an ink layer formed using the maximum number of nozzle rows available when forming one ink layer. Furthermore, focusing on the color of the ink ejected from the nozzle rows, the 4C layer 162 can be considered, for example, as an ink layer formed using the maximum number of ink colors available when forming a single ink layer in the configuration of the head unit 102. In contrast, in this example, the WPr layer 164 is an ink layer formed using only a portion of the nozzle rows arranged in the same row (second row) as the nozzle rows for white ink. In this case, the WPr layer 164 can also be considered as an ink layer formed using fewer nozzle rows than the maximum number of nozzle rows available when forming a single ink layer. Furthermore, the WPr layer 164 can also be considered as an ink layer formed using fewer ink colors than the maximum number of ink colors available when forming a single ink layer in the configuration of the head unit 102.

[0036] Furthermore, focusing on the number of nozzle rows used to form a single ink layer, if we consider forming an ink layer with a small thickness difference from the 4C layer 162 as the ink layer to be superimposed on the 4C layer 162 in the lower laminated section 52, then for that ink layer, it is conceivable to use all the nozzle rows aligned in the main scanning direction, with their positions in the sub-scanning direction aligned with the nozzle rows for the white ink, to form the ink layer. More specifically, in this example, it is conceivable to form an ink layer using clear ink instead of the WPr layer 164. However, in this case, the proportion of inks other than white increases, which may lead to a decrease in light reflectivity and opacity of the ink layer. In contrast, in this example, by using only one color of ink other than white, the decrease in light reflectivity and opacity of the ink layer superimposed on the 4C layer 162 can be appropriately suppressed. Also, in this case, by using primer ink, a layer of highly adhesive ink can be appropriately formed as the WPr layer 164. Therefore, according to this example, for example, it is possible to appropriately form layers of ink with high light reflectivity and opacity between the 4C layers 162, while appropriately preventing separation between the ink layers in the lower laminated portion 52.

[0037] Furthermore, as described above, in this example, the 4C layer 162 and the WPr layer 164 are examples of the first and second column corresponding layers. In this case, the relationship between the 4C layer 162 and the WPr layer 164 in this example can be considered by focusing on, for example, the number of nozzle rows used when forming the first and second column corresponding layers, and the relationship between the thickness of the ink layers. In this case, if we define the number of nozzle rows used to form the first column corresponding layer corresponding to the 4C layer 162 (number of first nozzle rows) as the number of nozzle rows when forming the first column corresponding layer, and the number of nozzle rows used to form the second column corresponding layer corresponding to the WPr layer 164 (number of second nozzle rows) as the number of nozzle rows when forming the second column corresponding layer, then, for example, the number of nozzle rows when forming the first column corresponding layer can be considered to be greater than the number of nozzle rows when forming the second column corresponding layer. Furthermore, in this case, focusing on the relationship between the thickness of the ink layer and the operation of the control unit 110, it can be considered that the control unit 110 causes, for example, the first-row corresponding layer to form an ink layer on the head unit 102 that is thicker than the second-row corresponding layer and less than three times the thickness of the second-row corresponding layer. With this configuration, for example, the difference in thickness between the ink layers that are alternately stacked in the lower stacking unit 52 can be appropriately reduced. In addition, this makes it less likely for separation to occur between the ink layers.

[0038] Furthermore, regarding the 4C layer 162 and the WPr layer 164, considering the number of nozzle rows used when forming the ink layers, the thickness of the 4C layer 162 is thought to be, for example, about twice the thickness of the WPr layer 164. However, in the actual thickness of the formed ink layers, the thickness of the 4C layer 162 may not be exactly twice the thickness of the WPr layer 164, but may be slightly less than twice. More specifically, the thickness of the 4C layer 162 may be, for example, less than twice the thickness of the WPr layer 164. Therefore, with respect to the first-row corresponding layer and the second-row corresponding layer corresponding to the 4C layer 162 and the WPr layer 164, it is preferable that the thickness of the first-row corresponding layer be, for example, 1.5 times or more the thickness of the second-row corresponding layer. With this configuration, for example, a first-row corresponding layer with a larger thickness can be appropriately used. It is more preferable that the thickness of the first-row corresponding layer be 1.7 times or more the thickness of the second-row corresponding layer. Furthermore, it is more preferable that the thickness of the first column-compatible layer be 1.8 times or more the thickness of the second column-compatible layer. In this case, it is more preferable that the thickness of the first column-compatible layer be less than, for example, 2.5 times the thickness of the second column-compatible layer. With this configuration, for example, the difference in thickness between the first column-compatible layer and the second column-compatible layer can be appropriately reduced. This also makes it possible to appropriately create printed materials with multiple layers of ink, for example. The thickness of the first column-compatible layer may be, for example, twice the thickness of the second column-compatible layer or less. For example, the thickness of the first column-compatible layer may be less than twice the thickness of the second column-compatible layer. Also, the thickness of the first column-compatible layer may be less than 1.9 times the thickness of the second column-compatible layer.

[0039] Furthermore, as explained above, separation between ink layers is particularly likely to occur at the interface where a thinner ink layer is on the bottom and a thicker ink layer, such as the 4C layer 162, is on top. In this example, the 4C layer 162 and the WPr layer 164 in the lower laminated section 52 are stacked in such a way that this hierarchical relationship occurs. More specifically, in this example, the control unit 110 of the printing apparatus 12 causes a plurality of 4C layers 162 to be formed on the head unit 102, and causes at least some of the 4C layers 162 to be formed on the head unit 102 so as to be in contact with the WPr layer 164 and overlapping the WPr layer 164. In this case, at least some of the 4C layers 162 can be considered to overlap, for example, the WPr layer 164. In contrast, in this example, as described above, by reducing the difference in thickness between the 4C layer 162 and the WPr layer 164, separation between the ink layers can be made less likely, even when the 4C layer 162 and the WPr layer 164 overlap in such a relationship. Also, as explained above, in this example, the nozzle rows for the white ink and primer ink are an example of a second nozzle row. In this case, the head unit 102 can be considered to have, for example, multiple second nozzle rows. Furthermore, regarding the formation of the WPr layer 164 using the white ink and primer ink, it can be considered to correspond to forming a second-row corresponding layer using ink ejected from multiple second nozzle rows. With this configuration, for example, a second-row corresponding layer that is thicker than the ink layer formed using only one second nozzle row can be appropriately formed. In addition, this makes it possible to appropriately form a second-row corresponding layer with a small difference in thickness from the first-row corresponding layer. Furthermore, in this case, the multiple second nozzle rows used to form the second-row corresponding layer can be considered as, for example, multiple nozzle rows that eject inks of different colors. And, as in this example, when forming the WPr layer 164 as the second-row corresponding layer, it can be considered that one of these multiple second nozzle rows will be a nozzle row that ejects light-reflective ink. Alternatively, it can be considered that another second nozzle row will be a nozzle row that ejects ink other than light-reflective ink.Furthermore, in this case, regarding the use of a primer ink as an ink other than a light-reflective ink, one example is to use a colorless ink as the ink other than a light-reflective ink. With this configuration, for example, a layer of light-reflective ink that has opacity to the color of the first-row corresponding layer can be appropriately formed as the second-row corresponding layer, while further using an ink other than a light-reflective ink.

[0040] Furthermore, in a modified operation of the printing apparatus 12, the ink layer that overlaps with the 4C layer 162 in the lower laminated section 52, such as the WPr layer 164, may be formed using only one color of ink. In this case, for example, a thick ink layer can be formed using only one color of ink by using a head unit 102 with an increased number of nozzle rows for white ink. More specifically, in this case, for example, multiple inkjet heads 202 for white ink can be used in the head unit 102 to increase the number of nozzle rows for white ink that become the second nozzle row. Even with this configuration, for example, by forming an ink layer of the same thickness as the WPr layer 164 described above, separation between ink layers in the lower laminated section 52 can be appropriately prevented. In addition, as a method to reduce the difference in thickness between overlapping ink layers in the lower laminated section 52, methods other than increasing the thickness of ink layers other than the 4C layer 162 can be considered, such as reducing the thickness of the 4C layer 162. More specifically, in the operation described above, when forming the 4C layer 162, the moving drive unit 106 causes each inkjet head 202 to eject ink at the density of solid printing. In this case, the inkjet head 202 used to form the 4C layer 162 can be considered to eject ink at a duty cycle of, for example, 100%. Duty cycle can be considered as, for example, the ratio of the amount of ink ejected per unit area. In contrast, when reducing the thickness of the 4C layer 162, the moving drive unit 106 causes each inkjet head 202 to eject ink at a density lower than the density of solid printing. In this case, the inkjet head 202 used to form the 4C layer 162 can be considered to eject ink at a duty cycle of, for example, less than 100%. Even with this configuration, for example, the difference in thickness between the overlapping ink layers in the lower stacking section 52 can be reduced. Also, in this case, the ink layers that are alternately stacked with the 4C layer 162 may be formed using only one color of ink, such as white ink.In this case as well, for example, by reducing the difference in thickness between the overlapping ink layers in the lower laminated section 52, separation between the ink layers in the lower laminated section 52 can be appropriately prevented. Also, in this case, the number of nozzle rows corresponding to the second nozzle row may be the same as the number of nozzle rows for one of the process colors (any of the YMCK colors).

[0041] Furthermore, in a further modification of the operation of the printing apparatus 12, for example, an ink layer other than the 4C layer 162 may be formed as the ink layer corresponding to the first column in the lower laminated section 52. In this case, for example, it is conceivable to form an ink layer using two or more colors of ink without using all four of the YMCK colors. In this case as well, by forming the lower laminated section 52 which includes an ink layer using multiple colors of ink, for example, the formation of the lower laminated section 52 can be carried out appropriately in a short time. Also, by setting the relationship between the thickness of the ink layers corresponding to the first column and the second column as described above, separation between the ink layers in the lower laminated section 52 can be appropriately prevented. In a further modification of the operation of the printing apparatus 12, for example, an ink layer using three or more colors of ink may be formed as the ink layer corresponding to the second column. Furthermore, the head section 102 may have a nozzle row for inks of colors other than process colors as the first nozzle row. In this case, as the ink layer corresponding to the first row, for example, an ink layer may be formed using the four YMCK inks and inks of other colors. In these cases as well, by setting the relationship between the thicknesses of the ink layers corresponding to the first row and the second row as described above, separation between the ink layers in the lower laminated portion 52 can be appropriately prevented.

[0042] Furthermore, in Figures 2(a) and (b), for illustrative purposes, the ink layers stacked on the medium 50 were depicted as having a flat top surface. In contrast, the ink stack actually formed on the medium 50 may have an uneven surface with varying heights depending on the location. In this case, the head unit 102 forms an ink stack with an uneven top surface by, for example, varying the number of ink layers stacked in the lower stacking section 52 depending on the location. Also, in this case, when forming the WPr layer 164 in the lower stacking section 52, the control unit 110 causes the head unit 102 to eject ink so that the ink dots formed with white ink and the ink dots formed with primer ink overlap at the same position. More specifically, in this case, the control unit 110 ejects ink into the nozzle rows for white ink and primer ink based on print data indicating the ejection positions of the white ink and primer ink. Furthermore, as such print data, for example, as shown in Figure 2(c), data is used that specifies the ejection of white ink and primer ink to the same pixel. In this case, pixels in the print data can be considered, for example, as image elements corresponding to ejection positions set according to the print resolution. With this configuration, for example, the head unit 102 can be appropriately made to form the WPr layer 164 using white ink and primer ink.

[0043] Furthermore, when multiple layers of ink are formed, various problems may arise in addition to separation between the ink layers. In this case, it is possible to consider modified versions of the operation of the printing device 12 to address these various problems. More specifically, when forming layers of ink in the printing device 12, for example, a bulge may occur at the contour, which is the edge of the ink layer, due to the influence of the surface tension of the ink. In this regard, if only one layer of ink is formed, such a bulge is usually not considered a problem. However, when multiple layers of ink are formed, the overlapping of these bulges can have a significant impact on the shape of the ink laminate. Therefore, in modified versions of the operation of the printing device 12, for example, it may be possible to form the ink layers in a way that minimizes such bulging, as needed. In this case, for example, adjusting the amount of ink ejected from the inkjet head 202 can make it less likely for bulging to occur at the contour of the ink layer. More specifically, as explained above, the inkjet head 202 of the head unit 102 of the printing device 12 may be configured to have a variable ink ejection capacity in multiple stages. In this case, for example, as shown in Figure 3, at least some of the ink dots formed on the contour portion 304 of the ink layer may be formed with an ink ejection capacity less than the maximum capacity, thereby making it less likely for the contour portion 304 to bulge.

[0044] Figure 3 illustrates a modified example of the operation of the printing apparatus 12. In Figure 3, the diagram above the arrow shows a simplified example of the state of ink dots formed on the inner circumference 302 and contour 304 of a single ink layer. In this case, the inner circumference 302 of the ink layer is, for example, the part inside the contour 304 of the ink layer. The inner circumference 302 can also be considered, for example, the part of the ink layer other than the contour 304. The contour 304 is the area that includes the outermost periphery of the ink layer. The contour 304 can also be considered, for example, a part of the ink layer along the outer periphery of the ink layer. The contour 304 can also be considered, for example, the area that includes the outermost periphery of the ink layer and surrounds the inner circumference 302. Also, in Figure 3, for the convenience of illustration and explanation, only a single ink layer formed on the medium 50 is shown. In the operation of forming an ink layer, the printing apparatus 12 forms an ink layer on the medium 50 by, for example, stacking an ink layer identical or similar to the ink layer shown in Figure 3. In the figure, the circle labeled L schematically represents an L-dot, which is an ink dot formed when the largest capacity of ink among multiple ejectable capacities is ejected from the nozzle of the inkjet head 202. The circle labeled S schematically represents an S-dot, which is an ink dot formed when the smallest capacity of ink among multiple ejectable capacities is ejected from the nozzle of the inkjet head 202. The circle labeled M schematically represents an M-dot, which is an ink dot formed when an intermediate capacity of ink among multiple ejectable capacities is ejected from the nozzle of the inkjet head 202.

[0045] Furthermore, in the example shown in Figure 3, the printing apparatus 12 forms the inner circumference 302 using only L dots, and forms the contour 304 using M dots and S dots without using L dots. In this case, the ink dots formed on the contour 304 can be considered, for example, ink dots formed by the ejection of ink at a capacity other than the maximum capacity. Also, in this regard, for example, if the goal is to form an ink laminate of a desired height in the shortest possible time, it is preferable to form the ink layer using only L dots. However, in this case, if the entire ink layer is formed using only L dots, bulging is likely to occur on the contour 304. In contrast, as shown in the illustrated example, if the contour 304 is formed using M dots or S dots, which are smaller in size than L dots, bulging on the contour 304 is less likely to occur. In this case, for example, as shown below the arrow in Figure 3, an ink layer that appropriately prevents bulging on the contour 304 can be appropriately formed. Therefore, this configuration effectively prevents the formation of large raised areas on the contours 304 of the ink layers. Furthermore, it allows for the more appropriate layering and formation of multiple ink layers. In this case, it is also possible to form the contours 304 of all the layered inks without using L-dots. This configuration effectively prevents the occurrence of raised areas in the ink laminate at positions corresponding to the contours 304. Depending on the required design and quality of the printed material, it is also possible to form the contours 304 of only some of the ink layers without using L-dots. Even in this configuration, it effectively prevents the occurrence of raised areas in the ink laminate at positions corresponding to the contours 304. The characteristics of forming the ink laminate in this way can also be considered by focusing on the operation of the control unit 110 (see Figure 1) in the printing apparatus 12.In this case, for example, when forming at least some of the ink layers, the control unit 110 causes the inkjet head 202 to eject ink at a capacity less than the maximum capacity at all ejection positions where ink is ejected in the contour portion 304. This operation of the control unit 110 can also be thought of as, for example, an operation that prevents the inkjet head 202 from ejecting ink at the maximum capacity to the contour portion 304.

[0046] Furthermore, regarding the contour portion 304, instead of not using L dots at all, it is conceivable to reduce the proportion of L dots compared to the inner circumference portion 302. In this case, for example, L dots would be formed at some ejection positions in the contour portion 304, and M dots or S dots would be formed at other ejection positions. Even with this configuration, for example, it is possible to appropriately prevent the occurrence of bulges in the ink laminate at positions corresponding to the contour portion 304. In this case, regarding the characteristics of forming the ink laminate in this way, for example, the ratio of ejection positions that eject ink at the maximum capacity among multiple ink capacities, relative to the ink ejection positions per unit area, can be defined as the maximum capacity ejection position ratio, and the operation of the control unit 110 can be considered. In this case, for example, when forming at least some of the ink layers, the control unit 110 causes the inkjet head 202 to eject ink such that the maximum capacity ejection position ratio in the contour portion 304 is smaller than the maximum capacity ejection position ratio in the inner circumference portion 302. With this configuration, for example, many ink layers can be appropriately stacked and formed. It is preferable for the control unit 110 to set the maximum capacity ejection position ratio as described above for all layers of ink to be stacked. With this configuration, for example, many layers of ink can be formed more appropriately. Depending on the design and quality required for the printed material, it is also possible to set the maximum capacity ejection position ratio as described above for only some of the ink layers. In this case, it is preferable for the control unit 110 to eject ink from the inkjet head 202 such that for more than half of the layers of ink to be stacked, the maximum capacity ejection position ratio at the contour portion 304 is smaller than the maximum capacity ejection position ratio at the inner circumference portion 302. With this configuration, for example, many layers of ink can be formed more appropriately.

[0047] Furthermore, when multiple layers of ink are formed, other problems may arise besides those mentioned above. For example, as explained above, when creating a printed material in which a laminate of inks is formed on a medium 50, it is possible to use UV-curing inks. In this case, it may be desirable to cure the ink dots to a glossy finish in the ink layer formed on the top surface of the laminate. More specifically, for example, when forming a clear layer, which is an ink layer formed with clear ink, on the top surface of the ink laminate, it may be desirable to cure the ink dots to a glossy finish in order to enhance glossiness. However, when forming a clear layer on top of a surface that already has multiple layers of ink, it may be difficult to properly form a clear layer that has been cured under glossy conditions.

[0048] In this regard, curing an ink layer under glossy conditions can be thought of as, for example, curing the ink after the ink dots have been flattened (leveled) following the ink's impact. Therefore, under glossy curing conditions, for example, the ink is allowed to harden for a certain amount of time after impact so that the ink dots are flattened and adjacent dots connect. However, in this case, if a clear layer is to be formed under glossy conditions on top of multiple ink layers that have already been layered, the clear layer may appear to be eroded, for example, near the edges of the ink layers. This eroded clear layer can be thought of as, for example, a state where the clear layer is not properly formed in part of the area where it should be formed. Furthermore, one possible cause of this problem is that the ink viscosity remains low during the time it takes to flatten the ink dots, which can lead to unintended ink movement. Moreover, it can be thought that this problem also occurs when forming ink layers other than the clear layer under glossy conditions. In contrast, in a modified version of the operation of the printing apparatus 12, for example, by forming the ink layer using the operation described below with reference to Figure 4, such problems can be made less likely to occur.

[0049] Figure 4 illustrates further variations in the operation of the printing apparatus 12. Figure 4(a) shows an example of the configuration of an ink laminate having a raised portion 62 and an overcoat portion 64, which is prone to problems related to this variation. In this case, the raised portion 62 can be considered, for example, as a portion that becomes convex on the surface of the medium 50 due to the overlapping of multiple ink layers on the medium 50. Alternatively, the raised portion 62 can be considered as a three-dimensional configuration in which the upper part is covered by the overcoat portion 64. For example, the raised portion 62 could form the lower laminate portion 52 and the upper decorative portion 54 (see Figure 2) in the configuration shown in Figure 2. In this case, for example, the raised portion 62 can be considered to have the lower laminate portion 52 and the upper decorative portion 54. The overcoat portion 64 is a portion that includes an ink layer covering the raised portion 62. In this case, the overcoat portion 64 can be considered to include, for example, an ink layer in which at least a part overlaps the raised portion 62. More specifically, in the example shown in Figure 4(a), the overcoat portion 64 is formed to cover the entire upper surface of the raised portion 62. In this case, the control unit 110 of the printing apparatus 12 (see Figure 1) causes the head unit 102 to form an overcoat portion 64 that covers the entire upper surface of the raised portion 62 by, for example, causing the head unit 102 to eject ink to an area that includes the raised portion range, which is the range in which ink is ejected from the head unit 102 (see Figure 1) when the raised portion 62 is formed, and to eject ink to an area wider than the raised portion range.

[0050] In this case, the overcoat portion 64 can also be considered to cover the sides of the raised portion 62, for example, as shown in the figure. The overcoat portion 64 covering the sides of the raised portion 62 can be considered, for example, by the ink that forms the overcoat portion 64 adhering to the sides of the raised portion 62. The ink that forms the overcoat portion 64 adhering to the sides of the raised portion 62 can be considered to correspond to, for example, having the head portion 102 dispense ink over a wider area than the raised portion area to form the overcoat portion 64, as described above. Furthermore, when forming the overcoat portion 64, the control unit 110 hardens the ink layer under conditions that result in a glossy finish. With this configuration, for example, the state of the upper surface of the ink laminate can be smoothed to enhance the glossiness. However, in this case, if the ink layer formed on the raised portion 62 is simply cured under glossy conditions, as described above, unintended ink movement may occur during the time it takes to flatten the ink dots, resulting in a situation where the ink layer is not properly formed in part of the area where the ink layer should be formed in the overcoat portion 64. Furthermore, this phenomenon is particularly likely to occur near the edges of the ink layer if, for example, the print head 102 is made to dispense ink over an area wider than the raised portion area when forming the overcoat portion 64.

[0051] In contrast, the inventors of the present invention have found that the formation of a glossy ink layer can be more appropriately achieved by curing the ink layer formed beneath the glossy ink layer under matte conditions. More specifically, in this case, for example, as shown in Figures 4(b) and (c), an overcoat portion 64 having a matte layer 172 and a glossy layer 174 can be formed on the raised portion 62. Figures 4(b) and (c) show examples of the configuration of the ink laminate formed in this modified example. In this case, the matte layer 172 is an ink layer formed while irradiating the ink dots with ultraviolet light from the ultraviolet light source 204 under conditions that cure the ink dots to a matte finish, and is formed so that at least a part of it overlaps with at least a part of the raised portion 62. The glossy layer 174 is an ink layer formed while irradiating the ink dots with ultraviolet light from the ultraviolet light source 204 under conditions that cure the ink dots to a glossy finish, and is formed so that at least a part of it overlaps with at least a part of the matte layer 172. In this case, the operation of the control unit 110 in the printing apparatus 12 can be considered as, for example, causing the head unit 102 to form the raised portion 62, the matte layer 172, and the gloss layer 174. Also, in the example shown in Figures 4(b) and (c), the control unit 110 causes the head unit 102 to form the matte layer 172 over an area wider than the raised portion 62 so that the matte layer 172 covers the entire raised portion 62. Regarding the matte layer 172 covering the entire raised portion 62, for example, it can be considered that the matte layer 172 is formed over an area wider than the entire upper surface of the raised portion 62 so that the matte layer 172 covers the entire upper surface and sides of the raised portion 62. Also, in this example, the control unit 110 causes the head unit 102 to form the gloss layer 174 over an area wider than the matte layer 172 so that the gloss layer 174 covers the entire matte layer 172. Regarding the gloss layer 174 covering the entire matte layer 172, for example, it can be considered that the gloss layer 174 is formed over a wider area than the entire upper surface of the matte layer 172, so that the gloss layer 174 covers the entire upper surface and sides of the matte layer 172. The upper surface of the matte layer 172 can be considered, for example, as the portion of the matte layer 172 that overlaps with the upper surface of the raised portion 62.The side surface of the matte layer 172 can be considered, for example, as the portion of the matte layer 172 that covers the side surface of the raised portion 62. In this case, the gloss layer 174 can also be considered as covering the entire raised portion 62 with the matte layer 172 sandwiched in between. With this configuration, for example, an overcoat portion 64 having the matte layer 172 and the gloss layer 174 that covers the raised portion 62 can be appropriately formed on the head portion 102.

[0052] Furthermore, with this configuration, for example, by forming a matte layer 172 below the gloss layer 174, it is possible to appropriately prevent unintended ink movement during the time it takes to flatten the ink dots when forming the gloss layer 174. Therefore, with this configuration, for example, the gloss layer 174 can be formed more appropriately over the desired area. Also, in this case, by forming the matte layer 172 over an area wider than the upper surface of the raised portion 62, for example, the area near the edge of the upper surface of the raised portion 62 will also be covered by the matte layer 172. And in this case, by forming the gloss layer 174 on top of the matte layer 172, for example, the gloss layer 174 can be formed more appropriately even near the edge of the upper surface of the raised portion 62. As for the overcoat portion 64, for example, it may be formed to cover at least a part of the medium 50 together with the raised portion 62. In this case, for example, as shown in Figure 4(c), the gloss layer 174 in the overcoat portion 64 covers at least a part of the medium 50 around the raised portion 62. In this case, the gloss layer 174 can be considered to cover at least a portion of the medium 50 together with the raised portion 62. With this configuration, for example, a design in which the entire raised portion 62 is covered with a glossy layer can be appropriately expressed. Also in this case, the matte layer 172 can be considered to be formed to cover at least a portion of the medium 50 together with the raised portion 62. With this configuration, for example, the matte layer 172 and gloss layer 174 covering the raised portion 62 can be appropriately formed.

[0053] Furthermore, when forming an overcoat portion 64 having a matte layer 172 and a gloss layer 174 as described above, the gloss layer 174 may be, for example, a clear layer. With this configuration, for example, a printed material expressing a highly glossy design can be appropriately formed. In this case, it is also preferable to form a clear layer as the matte layer 172. With this configuration, for example, a matte layer 172 that has little impact on the design expressed in the printed material can be appropriately formed. In addition, this makes it possible to more appropriately form a matte layer 172 and a gloss layer 174 that cover the entire raised portion 62. Furthermore, depending on the design to be expressed in the printed material, it is also possible to form a layer of ink made with an ink other than clear ink as the matte layer 172. In this case, the matte layer 172 may be, for example, a white layer made with white ink or a color layer made using process color ink. Furthermore, it is also possible to form a layer of ink made with an ink other than clear ink as the gloss layer 174. Regarding configurations using such matte layer 172 or gloss layer 174, for example, one can consider a configuration in which at least one of the matte layer 172 and gloss layer 174 in the overcoat portion 64 is a layer of ink other than the clear layer.

[0054] As explained above, the matte layer 172 is an ink layer formed by irradiating the ink dots with ultraviolet light from the ultraviolet light source 204 under conditions that cure the ink dots to a matte finish. The gloss layer 174 is an ink layer formed by irradiating the ink dots with ultraviolet light from the ultraviolet light source 204 under conditions that cure the ink dots to a glossy finish. In this case, regarding the curing conditions for curing the ink when forming the matte layer 172 and the gloss layer 174, curing the ink to a matte finish can be considered, for example, by curing the ink dots formed by the ink that landed at the ejection position without flattening them. Not flattening the ink dots can be considered, for example, by curing the ink dots before the ink dots have sufficiently flattened over time. Sufficiently flattening the ink dots can be considered, for example, by reaching a state where the ink dots can be considered flattened in the required print quality. Furthermore, curing the ink to a glossy finish can be considered, for example, by curing the ink after the ink dots formed by the ink that landed at the ejection position have sufficiently flattened. Regarding curing the ink to a glossy finish, one could consider, for example, curing the ink after a predetermined time has elapsed following the ink's impact to allow the ink dots to flatten. Furthermore, regarding the conditions for curing the ink dots to a matte or glossy finish, one could consider the same or similar conditions as those used for curing ink dots in known inkjet printers. In this case, curing the ink to a matte finish could be considered, for example, by curing the ink using the matte printing conditions pre-configured in the printing device 12. Similarly, curing the ink to a glossy finish could be considered, for example, by curing the ink using the gloss printing conditions pre-configured in the printing device 12.

[0055] More specifically, as a condition for curing the ink dots to a matte finish, one could consider using a condition where the ink dots ejected from the inkjet head 202 during each main scanning operation are cured during that main scanning operation. In this case, for example, the curing of the ink dots could be completed by ultraviolet light irradiated from an ultraviolet light source 204 that is located behind the inkjet head 202 in the direction of movement of the head unit 102 during the main scanning operation. To complete the curing of the ink dots, for example, it could be considered to irradiate the ink dots with ultraviolet light exceeding the cumulative light amount required to complete the curing of the ink according to the ink specifications. With this configuration, for example, a matte layer 172 can be appropriately formed. Furthermore, as a condition for curing the ink dots to a glossy finish, for example, it could be considered to complete the curing of the ink dots ejected from the inkjet head 202 during each main scanning operation after the main scanning operation is completed. In this case, for example, it could be considered to increase the viscosity of the ink to a state where curing is not completed by irradiating it with weak ultraviolet light from the ultraviolet light source 204 during the main scanning operation. In this case, for example, the ink dots formed by the ink ejected by the inkjet head 202 during each main scanning operation can be cured to a glossy finish by subsequently irradiating them with stronger ultraviolet light. Also, as can be understood from the matters explained above, the matte layer 172 can be considered as a layer of ink that is cured immediately after ejection from the inkjet head 202 to form ink dots. The matte layer 172 can also be considered as a layer of ink that does not flatten the ink dots. Furthermore, the gloss layer 174 can be considered as a layer of ink that is cured after waiting for a time for flattening after ejection from the inkjet head 202 to form ink dots. The gloss layer 174 can also be considered as a layer of ink that has been flattened.

[0056] Furthermore, in the configurations shown in Figures 4(b) and 4(c), the gloss layer 174 in the overcoat portion 64 is formed over a wider area than the matte layer 172. In contrast, in a further modification of the method of forming the overcoat portion 64, depending on the design to be expressed, for example, the gloss layer 174 may be formed over a narrower area than the matte layer 172. In this case as well, by forming the gloss layer 174 on top of the matte layer 172, for example, the gloss layer 174 can be formed more appropriately in the area where it should be formed. More specifically, in this case, for example, the matte layer 172 may be formed over a wider area than the raised portion 62, and the gloss layer 174 covering the entire upper surface of the raised portion 62 may be formed on top of it. Even with this configuration, for example, it is possible to appropriately prevent the gloss layer 174 from being eroded near the edge of the ink layer on the uppermost surface of the raised portion 62. Furthermore, in the configuration described above, the matte layer 172 can be considered as an ink layer with a different configuration from, for example, the ink layer formed in layers on the raised portion 62. In this case, the difference in the configuration of the ink layer can be considered as, for example, a difference in the ink used to form the ink layer or a difference in the method of forming the ink layer. The difference in the method of forming the ink layer can be considered as, for example, a difference in the printing conditions used when forming the ink layer. In this case, it is conceivable to use different printing conditions, such as the printing resolution and number of passes, when forming the ink layer on the raised portion 62 and when forming the matte layer 172. In contrast, in a modified example of the method of forming the matte layer 172, for example, an ink layer identical or similar to one of the ink layers formed in layers on the raised portion 62 may be formed as the matte layer 172. Even in this configuration, for example, the gloss layer 174 can be formed more appropriately by forming the matte layer 172 on top of the raised portion 62 and then forming the gloss layer 174 on top of that. In this case as well, it is preferable to form the matte layer 172 over a wider area than the raised portion 62, as described above. With this configuration, for example, the matte layer 172 that functions as a base for the gloss layer 174 can be formed more appropriately.Furthermore, depending on the required printing quality and the design to be expressed, the matte layer 172 may be formed only in an area corresponding to the upper surface of the raised portion 62. In this case, for example, the uppermost surface of the raised portion 62 can be considered to also serve as the matte layer 172. [Industrial applicability]

[0057] The present invention can be suitably used, for example, in a printing apparatus. [Explanation of Symbols]

[0058] 10...Printing system, 102...Head unit, 104...Stand unit, 106...Movement drive unit, 110...Control unit, 12...Printing device, 14...Control device, 152...White layer, 154...Color layer, 162...4C layer, 164...WPr layer, 172...Matte layer, 174...Gloss layer, 202...Inkjet head, 204...Ultraviolet light source, 302...Inner circumference, 304...Contour section, 50...Media, 52...Lower layer, 54...Upper decorative layer, 62...Raised section, 64...Overcoat section

Claims

1. A printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, An ink ejection unit having a nozzle row in which nozzles for ejecting ink onto the medium, A movement drive unit causes the ink ejection unit to perform a movement operation relative to the medium, A control unit that controls the operation of the ink ejection unit and the mobile drive unit. Equipped with, The moving drive unit causes the ink ejection unit to perform a main scanning operation in which it ejects ink while moving relative to the medium in at least a preset main scanning direction. The ink ejection unit has a plurality of nozzle rows, and the plurality of nozzle rows are, A plurality of first nozzle rows, which are a row of nozzles arranged in a first column that is aligned in the main scanning direction and whose positions are aligned in the sub-scanning direction that is perpendicular to the main scanning direction, At least one second nozzle row is the nozzle row that is aligned with the first row and the second row which is a row that is shifted in position in the sub-scanning direction. It has, The control unit controls the operation of the ink ejection unit and the moving drive unit, A first row corresponding layer is a layer of ink formed using the ink ejected from the plurality of first nozzle rows, A second row corresponding layer which is a layer of ink formed using ink ejected from at least one of the second nozzle rows. The ink ejection section is formed to form the ink ejection section. If the number of first nozzle rows used to form the first corresponding layer is defined as the number of nozzle rows during first corresponding layer formation, and the number of second nozzle rows used to form the second corresponding layer is defined as the number of nozzle rows during second corresponding layer formation, then the number of nozzle rows during first corresponding layer formation is greater than the number of nozzle rows during second corresponding layer formation. The printing apparatus is characterized in that the control unit causes the ink ejection unit to form the first column corresponding layer, which is thicker than the second column corresponding layer and less than three times the thickness of the second column corresponding layer.

2. The first nozzle row ejects colored inks of different colors that form the basic colors for color expression. The ink ejection unit has, as the second nozzle row, at least the nozzle row that ejects light-reflective ink, The printing apparatus according to claim 1, characterized in that the control unit causes the ink ejection unit to form the second corresponding layer using at least the light-reflective ink.

3. The ink ejection unit further includes, as the second nozzle row, a nozzle row that ejects an ink with higher adhesion to the medium than the light-reflective ink, The printing apparatus according to claim 2, characterized in that the control unit causes the ink ejection unit to form the second corresponding layer using the light-reflective ink and the adhesive ink.

4. The printing apparatus according to claim 2, characterized in that the control unit causes a plurality of the first row corresponding layers to be formed in the ink ejection unit, and at least some of the first row corresponding layers are formed in the ink ejection unit such that they are in contact with the second row corresponding layer and overlap the second row corresponding layer.

5. A printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, An ink ejection unit that ejects ink onto the aforementioned medium, A control unit that controls the operation of the ink ejection unit and Equipped with, The aforementioned ink ejection unit is A dispensing head that dispenses UV-curing ink, A UV light source that irradiates ultraviolet light to cure the aforementioned UV-curable ink, It has, The control unit, A raised portion is formed on the surface of the medium by the overlapping of multiple layers of the ink on the medium, A matte layer formed by irradiating the ink light source with ultraviolet light under conditions that cause the ink dots to harden into a matte finish, wherein at least a portion of the ink layer overlaps at least a portion of the raised portion, A gloss layer which is formed by irradiating the ink light source with ultraviolet light under conditions that cause the ink dots to harden to a glossy finish, and at least a portion of the ink layer overlaps at least a portion of the matte layer. A printing apparatus characterized by forming the ink ejection section.

6. The printing apparatus according to claim 5, characterized in that the control unit causes the ink ejection unit to form the mat layer over an area wider than the raised portion such that the mat layer covers the entire raised portion.

7. A printing apparatus that performs printing by ejecting ink onto a medium to be printed, thereby forming multiple layers of ink, An ink ejection unit that ejects ink onto the aforementioned medium, A control unit that controls the operation of the ink ejection unit and Equipped with, The ink ejection unit has an inkjet head that ejects ink using an inkjet method. The aforementioned inkjet head has a variable ink ejection capacity in multiple stages. The ratio of the ink ejection position that ejects ink at the maximum capacity among the multiple ink capacities is defined as the maximum capacity ejection position ratio, with respect to the ink ejection position per unit area. With respect to the ink layer formed in the ink ejection unit, if a portion of the ink layer including the outermost periphery is defined as the contour portion, and the portion of the ink layer inside the contour portion is defined as the inner periphery portion, A printing apparatus characterized in that, when forming at least a portion of the ink layer, the control unit causes the inkjet head to eject ink such that the ratio of the maximum capacity ejection position in the contour portion is smaller than the ratio of the maximum capacity ejection position in the inner circumference portion.

8. The printing apparatus according to claim 7, characterized in that, when forming at least a portion of the ink layer, the control unit causes the inkjet head to eject ink at a capacity less than the maximum capacity for all ejection positions that eject ink in the contour portion.

9. A printing method that performs printing by ejecting ink onto a medium to be printed on, thereby forming multiple layers of ink, An ink ejection unit having a nozzle row in which nozzles for ejecting ink onto the medium, A movement drive unit causes the ink ejection unit to perform a movement operation that moves relative to the medium. Using, The aforementioned moving drive unit causes the ink ejection unit to perform a main scanning operation in which it ejects ink while moving relative to the medium in at least a preset main scanning direction, The ink ejection unit has a plurality of nozzle rows, and the plurality of nozzle rows are, A plurality of first nozzle rows, which are a row of nozzles arranged in a first column that is aligned in the main scanning direction and whose positions are aligned in the sub-scanning direction that is perpendicular to the main scanning direction, At least one second nozzle row is the nozzle row that is aligned with the first row and the second row which is a row that is shifted in position in the sub-scanning direction. It has, By controlling the operation of the ink ejection unit and the moving drive unit, A first row corresponding layer is a layer of ink formed using the ink ejected from the plurality of first nozzle rows, A second row corresponding layer which is a layer of ink formed using ink ejected from at least one of the second nozzle rows. The ink ejection section is formed to form the ink ejection section. If the number of first nozzle rows used to form the first corresponding layer is defined as the number of nozzle rows during first corresponding layer formation, and the number of second nozzle rows used to form the second corresponding layer is defined as the number of nozzle rows during second corresponding layer formation, then the number of nozzle rows during first corresponding layer formation is greater than the number of nozzle rows during second corresponding layer formation. A printing method characterized in that the first column corresponding layer is formed in the ink ejection section, the first column corresponding layer being thicker than the second column corresponding layer and less than three times the thickness of the second column corresponding layer.

10. A printing method that performs printing by ejecting ink onto a medium to be printed on, thereby forming multiple layers of ink, Using an ink ejection unit that ejects ink onto the aforementioned medium, The aforementioned ink ejection unit is A dispensing head that dispenses UV-curing ink, A UV light source that irradiates ultraviolet light to cure the aforementioned UV-curable ink, It has, A raised portion is formed on the surface of the medium by the overlapping of multiple layers of the ink on the medium, A matte layer formed by irradiating the ink light source with ultraviolet light under conditions that cause the ink dots to harden into a matte finish, wherein at least a portion of the ink layer overlaps at least a portion of the raised portion, A gloss layer which is formed by irradiating the ink light source with ultraviolet light under conditions that cause the ink dots to harden to a glossy finish, and at least a portion of the ink layer overlaps at least a portion of the matte layer. A printing method characterized by forming the ink ejection section.

11. A printing method that performs printing by ejecting ink onto a medium to be printed on, thereby forming multiple layers of ink, Using an ink ejection unit that ejects ink onto the aforementioned medium, The ink ejection unit has an inkjet head that ejects ink using an inkjet method. The aforementioned inkjet head has a variable ink ejection capacity in multiple stages. The ratio of the ink ejection position that ejects ink at the maximum capacity among the multiple ink capacities is defined as the maximum capacity ejection position ratio, with respect to the ink ejection position per unit area. With respect to the ink layer formed in the ink ejection unit, if a portion of the ink layer including the outermost periphery is defined as the contour portion, and the portion of the ink layer inside the contour portion is defined as the inner periphery portion, A printing method characterized in that, when forming at least a portion of the ink layer, the inkjet head ejects ink such that the ratio of the maximum capacity ejection position in the contour portion is smaller than the ratio of the maximum capacity ejection position in the inner circumference portion.

Images