Printing apparatus and printing method

Abstract

Multiple layers of ink are appropriately stacked and formed on the medium. [Solution] A printing apparatus 12 that performs printing by stacking multiple layers of ink, comprising a head unit 102 which is an ink ejection unit, a base unit 104 which is a media holding unit, a moving drive unit 106, an information storage unit 108, and a control unit 110, wherein the moving drive unit 106 causes the head unit 102 to perform the main scanning operation and stacking direction movement, the information storage unit 108 stores multiple layer thickness information corresponding to different layer formation conditions, and the control unit 110 causes the head unit 102 to form multiple ink layers based on the layer formation condition associated with any of the layer thickness information, and controls the operation of stacking direction movement based on the layer thickness information corresponding to the layer formation condition.

Description

Technical Field

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

Background Art

[0002] In recent years, printing apparatuses that perform 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 a plurality of ink layers by overlapping them, 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, it may be difficult to form a large number of ink layers. 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 a method for more appropriately forming multiple ink layers on a medium using a printing apparatus. In this regard, it is possible to perform printing with multiple ink layers even with conventional inkjet printers and other printing apparatuses. In this case, it is often possible to perform printing with multiple ink layers up to a certain thickness (thick printing). However, when stacking multiple ink layers using an inkjet printer, for example, if many ink layers are stacked, the ink stack comes into contact with the inkjet head that ejects the ink, making it difficult to form a stack of higher (thicker) material. In contrast, it might seem that a thicker ink stack could be formed by increasing the head gap, which is the distance between the inkjet head and the medium. However, when attempting to stack ink layers under high-gap conditions with a large head gap, for example, when forming the lower layer of the stack, the longer flight distance of the ink makes it easier for the landing position to shift. In this case, it is also conceivable that there may be a large difference in the amount of landing position shift between the lower and higher layers of the stack. Furthermore, increasing the head gap can sometimes cause the ink to atomize before it hits the medium, making it difficult to form an ink layer at all. Therefore, simply increasing the head gap usually does not increase the thickness of the ink layer.

[0006] Therefore, the inventor of the present invention considered adjusting the head gap in conjunction with the operation of stacking ink layers. In this regard, for example, in the case of a 3D printer that uses a special material to create a shape, the thickness of one layer formed by the material can be treated as a known, constant thickness. However, in a printing device, when attempting to express various designs by stacking many ink layers, the thickness of one ink layer may vary depending on the design to be expressed, for example. More specifically, for example, when attempting to form a high-density stack in a shorter time, it is conceivable to use multiple inkjet heads for at least some of the ink layers and increase the amount of ink ejected per unit time from each inkjet head. In contrast, for example, when forming an ink layer of a predetermined color using only one inkjet head, or when forming an ink layer to represent a color image, thinner ink layers are usually formed. Furthermore, in a printing device, inks with various characteristics may be used depending on the quality required for the printed material to be created. In this case, for example, the user will use ink selected from among several types of inks (ink sets) available for use in the printing device. In this case, the thickness of the ink layer may vary depending on the type of ink used. Furthermore, when attempting to express various designs by layering multiple ink layers in a printing device, it may be necessary to form many ink layers, such as 50 or more. In this case, if the thickness of a single ink layer varies considerably, the height of the resulting laminate will differ significantly depending on the type of ink layer used. This can also make it difficult to properly adjust the head gap.

[0007] In response to this, the inventors of the present invention considered adjusting the head gap not simply by changing it by a fixed percentage, but based on information indicating the actual thickness of the ink layer to be formed. Furthermore, in this case, they considered causing the ejection head, such as an inkjet head, to perform a stacking direction movement relative to the medium, based on layer thickness information indicating the thickness of the ink layer in correspondence with the layer formation conditions, which are the conditions for forming the ink layer. Moreover, in this case, they considered preparing multiple layers of layer thickness information corresponding to different layer formation conditions in advance, and causing the ejection head to perform a stacking direction movement based on the layer thickness information corresponding to the layer formation conditions actually used when forming the ink layer. With this configuration, for example, the ejection head can be appropriately made to perform a stacking direction movement to adjust the head gap. Furthermore, this makes it possible to appropriately stack and form a large number of ink layers on a medium using a printing device, for example.

[0008] 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 for ejecting ink onto the medium; a medium holding unit for holding the medium on a surface opposite to the ink ejection unit; a movement drive unit for causing the ink ejection unit to perform a movement operation relative to the medium; a control unit for controlling the operation of the ink ejection unit and the movement drive unit; and an information storage unit for storing information used by the control unit, wherein the movement drive unit performs a main scanning operation in which it moves relative to the medium in a preset main scanning direction while ejecting ink, and the distance between the opposing surface and the ink ejection unit changes in the stacking direction, which is the direction in which the multiple layers of ink overlap, as described above. The present invention provides a method for causing the ink ejector to perform a stacking direction movement, which involves moving at least one of the ink ejector unit and the media holding unit in the stacking direction relative to the medium; the information storage unit stores layer thickness information indicating the thickness of the ink layer in association with layer formation conditions, which are the conditions for forming the ink layer, and stores a plurality of layers of layer thickness information corresponding to different layer formation conditions; and the control unit controls the operation of the ink ejector unit and the movement drive unit based on the layer formation conditions associated with any of the layer thickness information, thereby causing the ink ejector unit to form the plurality of ink layers, and controls the stacking direction movement operation that the movement drive unit causes the ink ejector unit to perform based on the layer thickness information corresponding to the layer formation conditions.

[0009] With this configuration, for example, the ink ejection unit can be appropriately moved in the stacking direction according to the thickness of the ink layers to be stacked. This also allows for the appropriate stacking and formation of multiple ink layers on a medium in a printing apparatus. In this configuration, the ink ejection unit has, for example, an ejection head that ejects ink. In this case, the movement operations such as the main scanning operation and stacking direction movement of the ink ejection unit can be considered as, for example, having the ejection head in the ink ejection unit perform the movement operation. As the ejection head, for example, an inkjet head that ejects ink using an inkjet method can be suitably used. Furthermore, in this configuration, the control unit causes the ink ejection unit to form, for example, 50 or more layers of ink stacked on top of each other. With this configuration, for example, a stack of inks that is convex on the surface of the medium can be appropriately formed on the medium. The control unit may cause the ink ejection unit to form even more ink layers. For example, the control unit may cause the ink ejection unit to form 100 or more layers of ink stacked on top of each other.

[0010] In this configuration, the information storage unit stores, for example, a plurality of layer thickness information corresponding to a plurality of layer formation conditions in which the method of using the ejection head during the formation of ink layers differs from one another. In this case, the ink ejection unit forms a plurality of ink layers by stacking multiple ink layers, for example, an ink layer formed under a first layer formation condition and an ink layer formed under a second layer formation condition different from the first layer formation condition. The control unit also causes the ink ejection unit to perform multiple stacking direction movements while forming at least one ink layer in between. With this configuration, for example, laminates of ink with various configurations can be appropriately formed. In this case as well, the operation of the stacking direction movement caused by the movement drive unit to the ink ejection unit can be appropriately controlled based on the layer thickness information. In this configuration, the ink ejection unit may have, for example, a plurality of nozzle rows. In this case, the ink ejection unit has, for example, a plurality of ejection heads, thereby having a plurality of nozzle rows. The ejection head may also have a plurality of nozzle rows. In this case, the ink ejection unit has multiple nozzle rows, for example, by having multiple nozzle rows in the ejection head. Furthermore, when the ink ejection unit has multiple nozzle rows, the information storage unit stores multiple layer thickness information corresponding to multiple layer formation conditions in which the number of nozzle rows used to form the ink layers differs from one another. In this case, it is conceivable to use conditions in which the number of nozzle rows used to form the ink layers differs from one another as the first layer formation condition and the second layer formation condition. With this configuration, for example, even when stacking multiple ink layers in which the number of nozzle rows used to form the ink layers differs from one another, the ink ejection unit can be made to move appropriately in the stacking direction.

[0011] Furthermore, the ink ejection unit may have, for example, multiple nozzle rows that eject inks of different colors. In this case, the first layer formation condition could be, for example, a condition for forming an ink layer using only one preset color of ink. The second layer formation condition could be, for example, a condition for forming an ink layer using N preset colors (where N is an integer of 2 or more) of ink. When forming ink layers under these layer formation conditions, regarding the relationship between the thickness of the ink layer formed under the second layer formation condition and the thickness of the ink layer formed under the first layer formation condition, for example, the thickness corresponding to the second layer formation condition may not simply be N times the thickness corresponding to the first layer formation condition, but may be smaller than N times the thickness. Therefore, in this case, the thickness of the ink layer indicated by the layer thickness information corresponding to the second layer formation condition may be, for example, smaller than N times the thickness of the ink layer indicated by the layer thickness information corresponding to the first layer formation condition. With this configuration, for example, the ink ejection unit can be made to move appropriately in the stacking direction. Furthermore, if the ink ejection unit has multiple nozzle rows that eject inks of different colors, it is conceivable that, for example, the thickness of the formed ink layers may differ depending on the color of the ink used to form the ink layers. In this case, the information storage unit stores, for example, multiple layers of thickness information corresponding to multiple layer formation conditions in which the ink colors used to form the ink layers are different from each other. In this case, the information storage unit also stores, for example, information that is different from the layers of thickness information corresponding to other ink colors as layer thickness information corresponding to at least some of the ink colors. In this case, it is conceivable that, for example, conditions in which the ink colors used to form the ink layers are different from each other could be used as the first and second layers of layer formation conditions. With this configuration, for example, even when stacking ink layers formed with inks of different colors, the ink ejection unit can be made to move appropriately in the stacking direction. Furthermore, it is conceivable that the ink layers could be formed using, for example, multiple colors of ink.In this case, with respect to the first layer formation condition and the second layer formation condition, the difference in the color of the ink used to form the ink layer can be considered, for example, by having different colors for at least some of the inks used to form the ink layer. Alternatively, the difference in the color of the ink used to form the ink layer can be considered, for example, by having different combinations of ink colors used when forming the ink layer.

[0012] Furthermore, the ejection head could be configured to eject multiple types of ink with different characteristics. In this case, the ejection head could be considered capable of ejecting inks included in an ink set selected from multiple different ink sets. In this case, the thickness of the ink layer formed using the ink could change depending on the characteristics of the ink used. Therefore, in this case, the information storage unit could store multiple layer thickness information corresponding to multiple types of ink. The control unit could then control the movement of the ink ejection unit in the stacking direction based on the layer thickness information corresponding to the ink used in the ejection head. With this configuration, the ink ejection unit could be made to move appropriately in the stacking direction, even when various types of ink are used in the ejection head. In addition, the printing apparatus could use multiple types of ejection heads with different characteristics. In this case, the ejection head attached to the printing apparatus could be appropriately replaced depending on the quality required for the printed material to be created. In this case, the thickness of the ink layer formed using the ejection head could change depending on the characteristics of the ejection head used. Therefore, in this case, the information storage unit stores, for example, multiple layers of thickness information corresponding to multiple types of ejection heads. The control unit then controls the operation of the movement drive unit related to stacking direction movement based on, for example, the layer thickness information corresponding to the ejection head used to form the ink layers. With this configuration, for example, even when various types of ejection heads are used in a printing device, the ink ejection unit can be made to move appropriately in the stacking direction.

[0013] Furthermore, in this configuration, the control unit causes the ink ejector unit to perform multiple stacking direction movements, for example, while forming at least one ink layer in between. If the distance the ink ejector unit moves relative to the medium in one stacking direction movement is defined as the stacking direction movement distance, the control unit determines the stacking direction movement distance based, for example, on layer thickness information corresponding to the layer formation conditions. In this case, for example, the control unit determines the stacking direction movement distance for the later of two consecutive stacking direction movements based on layer thickness information corresponding to the layer formation conditions used when forming the ink layer between the two stacking direction movements. With this configuration, for example, the ink ejector unit can be made to perform stacking direction movements appropriately in accordance with the height (thickness) of the ink layer being stacked. Furthermore, the stacking direction movement distance can be set to a predetermined constant distance, for example. In this case, the control unit determines the timing for performing the stacking direction movement based, for example, on layer thickness information corresponding to the layer formation conditions used when forming the ink layer being stacked. Furthermore, the control unit controls the operation of the movement drive unit so that, for example, selective movement in the stacking direction occurs at the timing when some ink layers have been formed, in accordance with the height of the stacked ink layers. Even with this configuration, for example, the ink ejection unit can be appropriately made to move in the stacking direction in accordance with the height of the stacked ink layers.

[0014] Furthermore, in this configuration, if the distance between the formed layer and the ejection head at the time when the formation of a new ink layer begins on top of the already stacked ink layer is defined as the layer-head distance, the movement drive unit causes the ink ejection unit to move in the stacking direction so that the layer-head distance becomes a distance within a preset range. With this configuration, for example, the layer-head distance during the formation of ink layers can be kept within an appropriate range. This also allows for the proper formation of ink layers. In this case, the stacking direction movement does not necessarily have to be performed every time a certain number of ink layers are formed, but can be performed as appropriate, for example, when the layer-head distance becomes narrower. In this case, for example, the number of ink layers formed by the ink ejection unit between two consecutive stacking direction movements can be considered variable. More specifically, if we define the number of ink layers formed by the ink ejection unit between two consecutive stacking direction movements as the number of layers between stacking direction movements, then the number of layers between stacking direction movements after the first stacking direction movement (which is one of the stacking direction movements) may be different from the number of layers between stacking direction movements after the second stacking direction movement (which is one of the stacking direction movements other than the first). With this configuration, for example, the ink ejection unit can be made to perform stacking direction movements appropriately when necessary.

[0015] Furthermore, in this configuration, for example, UV-curable ink can be used as the ink. In this case, the ink ejection unit has, for example, an ejection head that ejects UV-curable ink and a UV light source that irradiates UV light to cure the UV-curable ink. In this case, the control unit causes the ink ejection unit to perform a main scanning operation while irradiating the UV light source with UV light, thereby forming an ink layer on the ink ejection unit. With this configuration, for example, UV-curable ink can be used to appropriately stack and form multiple ink layers. However, in this case, for example, depending on the characteristics of the ink used, among the multiple ink layers to be stacked, the ink layer formed earlier may be irradiated with UV light during the formation of the ink layer formed later, which may cause the ink to harden more than necessary, resulting in a problem of over-hardening. This problem is particularly likely to occur when stacking translucent inks such as clear ink. Therefore, in this case, for example, it is conceivable to reduce the intensity of the UV light irradiated during the formation of the ink layer in the lower part of the stacked ink layers. More specifically, if we define the uppermost layer of a predetermined number of ink layers stacked by the ink ejection unit as the upper layer, and the other ink layers as the lower layer, then when forming the upper layer, the control unit causes the ink ejection unit to perform a main scanning operation while irradiating the ink ejection unit with ultraviolet light at a predetermined first intensity. Then, when forming the lower layer, the control unit causes the ink ejection unit to perform a main scanning operation while irradiating the ink ejection unit with ultraviolet light at a second intensity, which is weaker than the first intensity. With this configuration, problems such as over-hardening in the lower ink layers can be appropriately prevented. In this case, the second intensity can be considered, for example, an intensity that does not completely harden the ink during the main scanning operation that forms the ink layer. Also, in this case, when forming the upper ink layer, the ink layer can be appropriately hardened by irradiating it with stronger ultraviolet light.

[0016] Furthermore, as a configuration of the present invention, for example, a configuration focusing on the above-mentioned features of causing the ink ejection unit to move in the stacking direction so that the distance between layer heads is within a predetermined range, or the above-mentioned features of using ultraviolet-curable ink, can also be considered. Furthermore, as a configuration of the present invention, for example, a configuration of a printing method having the same features 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, multiple layers of ink can be appropriately stacked and formed on a medium. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 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 raised portion 52 in the ink laminate formed on the medium 50. Figure 2(c) shows another example of the structure of the raised portion 52. [Figure 3] This diagram shows an example of the information stored in the information storage unit 108. [Figure 4] This figure illustrates an example of the timing for causing the head unit 102 to move in the stacking direction. Figures 4(a) to (c) show examples of ink layers formed on the medium 50, along with the inkjet head 202 in the head unit 102. [Figure 5] This figure illustrates an example of the timing for causing the head unit 102 to move in the stacking direction. Figures 5(a) to (c) show examples of ink layers formed on the medium 50, along with the inkjet head 202 in the head unit 102. [Figure 6] It is a diagram showing an example of the structure of a laminate of ink with an uneven surface. Figs. 6(a) to (c) show various specific examples regarding the structure of the laminate of ink.

Embodiments for Carrying out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a diagram for explaining a printing system 10 according to an embodiment of the present invention. Fig. 1(a) shows an example of the configuration of the printing system 10. Fig. 1(b) shows an example of the configuration of the printing device 12 in the printing system 10. Fig. 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 their respective parts. In this example, the printing system 10 is a system that performs printing by forming an ink layer on a medium (media) 50 to be printed, and includes a printing device 12 and a control device 14. The printing device 12 is a device that executes printing in the printing system 10. In this example, the printing device 12 is an inkjet printer that performs printing by the inkjet method, and performs printing by discharging ink onto the media 50 to form a plurality of ink layers stacked on top of each other. Further, thereby, the printing device 12 forms a convex ink laminate on the surface of the media 50 on the media 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, an information storage unit 108, 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 inkjet heads 202 for spot colors, including inkjet heads 202 for white (W) ink, clear ink (CL), and primer (Pr) ink. 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 process color inks. In this example, white ink is an example of a light-reflective ink. Clear ink is a colorless and transparent ink. The fact that clear ink 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.

[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 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, as shown in the figure for example. Also, the plurality of inkjet heads 202 for special colors 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 modified example of the configuration of the head unit 102, the inkjet heads 202 for special colors 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 colors other 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, for 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 may be considered. Further, in the head unit 102, the plurality of ultraviolet light sources 204 are light sources that irradiate ultraviolet rays for curing ultraviolet curable ink. In this example, the ultraviolet light sources 204 are arranged on one side and the other side of the plurality of inkjet heads 202 in the main scanning direction.

[0022] 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.

[0023] 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.

[0024] 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, the head gap can be appropriately adjusted to match, for example, the height (thickness) of the ink layers to be stacked on the media 50. In addition, this makes it possible to appropriately form multiple ink layers on the media 50. The stacking direction movement that the moving drive unit 106 causes the head unit 102 to perform will be explained in more detail later.

[0025] Furthermore, the information storage unit 108 is configured to store information used by the control unit 110. In this example, the information storage unit 108 stores, for example, information used for control related to movement in the stacking direction. In addition, as such information, the information storage unit 108 stores layer thickness information indicating the thickness of the ink layer, associated with the layer formation conditions, which are the conditions for forming the ink layer. In this example, the information storage unit 108 stores multiple layers of layer thickness information corresponding to different layer formation conditions. The information stored in the information storage unit 108 will be explained in more detail later. Furthermore, the control unit 110 is configured to include, 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 the printing 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 printing 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, to cause the head unit 102 to perform a main scanning operation while irradiating the ultraviolet light source 204 in the head unit 102 with ultraviolet light. The control unit 110 also causes the head unit 102 to perform a main scanning operation while, for example, performing a sub-scanning operation as needed, thereby forming layers of ink 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, to cause the head unit 102 to move in the stacking direction as needed, thereby forming multiple layers of ink on the head unit 102. According to this example, for example, multiple layers of ink 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 raised portion 52 in the ink laminate formed on the medium 50. In this example, the printing apparatus 12 forms an ink laminate on the medium 50, including, for example, a raised portion 52 and an upper decorative portion 54, by stacking multiple layers of ink. In this case, the raised portion 52 can be considered, for example, a raised-shaped part formed by stacking multiple layers of ink on the medium 50. The raised portion 52 can also be considered, for example, a thick-layered portion formed by stacking layers of ink in a thick layer. The raised portion 52 can also be considered, for example, the part of the ink laminate formed on the medium 50 other than the uppermost upper decorative portion 54. In this example, the raised portion 52 is formed by stacking multiple 4C layers 162, as shown in Figure 2(b). The 4C layer 162 is an ink layer formed using the four process color inks, YMCK (CMYK). 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 inkjet heads 202 aligned in the main scanning direction and positioned 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. Also, in this case, by stacking the 4C layers 162 to form the raised portion 52, for example, the formation of the raised portion 52 can be carried out appropriately in a short time. The density of the solid print 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 the solid print, 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. Also, as the inkjet head 202, for example, a configuration in which the amount of ink ejected is variable in multiple stages can be used. In this case, when forming the 4C layer 162, the inkjet head 202 ejects, for example, the maximum amount of ink relative 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), the inkjet head 202 will eject ink at, for example, a large capacity, at the ejection position where ink is ejected during the formation of the 4C layer 162. With this configuration, for example, a 4C layer 162 with a large thickness can be formed more appropriately.

[0029] 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 that expresses a design 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 raised portion 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 from white ink ejected from an inkjet head 202 for white ink. The white layer 152 can be considered, for example, as a light-reflecting layer formed from light-reflecting ink. In this example, the white layer 152 is formed between the raised portion 52 and the color layer 154, so that it functions as a concealing layer that hides the color of the raised portion 52, while also functioning as a background for the color layer 154. In this case, by forming a color layer 154 on top of the white layer 152, for example, the influence of the color of the raised portion 52 can be appropriately suppressed while allowing the observer to appropriately perceive the color expressed by the color layer 154. In this example, the moving drive unit 106 forms the white layer 152 on the head unit 102 by, for example, ejecting ink at the density of solid printing from the inkjet head 202 for white ink. In this case, by forming the white layer 152 with fewer inkjet heads 202 than when forming the 4C layer 162, the thickness of the white layer 152 becomes smaller than that of the 4C layer 162. In this case, the ink laminate formed by the printing device 12 on the medium 50 can also be considered as, for example, multiple layers of ink of different thicknesses stacked on top of each other. 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 process color inks to color it can be considered, for example, to mean that the color layer 154 is colored using ink of a color that matches the design to be expressed by 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 from among the ejection positions set in the print resolution, according to the design to be expressed.In this case, regarding the operation of the inkjet head 202, it can be considered that the amount of ink ejected per unit area is less compared to, for example, when performing solid color printing. Therefore, in this example, the thickness of the color layer 154 is also smaller than that of the 4C layer 162.

[0030] Furthermore, the printing apparatus 12 may form a raised portion 52 with a configuration different from that shown in Figure 2(b). In this case, the printing apparatus 12 forms a raised portion 52 with a configuration including a 4C layer 162 and a white layer 164, for example, as shown in Figure 2(c). Figure 2(c) shows another example of the configuration of the raised portion 52. In this case, the moving drive unit 106 causes the head unit 102 to form a layer of ink that is the same as or similar to the white layer 152 in the upper decorative portion 54, for example, as the white layer 164. In this case, the moving drive unit 106 causes the head unit 102 to form the 4C layer 162 and the white layer 164, for example, so that they overlap alternately. Even with this configuration, the formation of the raised portion 52 can be carried out appropriately in a short time by forming a raised portion 52 having a 4C layer 162, for example. Furthermore, in this case, by forming a white layer 164 between the 4C layers 162, it is possible to prevent, for example, the color of the 4C layer 162 from being excessively conspicuous. Also, when forming a raised portion 52 with such a configuration, for example, the white layer 152 in the upper decorative portion 54 may be omitted by forming a white layer 164 at the top of the raised portion 52. In a further modification of the configuration of the raised portion 52, the printing apparatus 12 may form a raised portion 52 that further includes a layer of ink other than those described above. In this case, for example, it is conceivable to form a raised portion 52 that further includes a color layer identical or similar to the color layer 154 in the upper decorative portion 54.

[0031] As explained above, in this example, the movement drive unit 106 causes the head unit 102 to move in the stacking direction. In this case, the movement drive unit 106 causes the head unit 102 to move in the stacking direction in accordance with the increase in the height of the stacked ink layer, so that the stacked ink layer does not come into contact with the inkjet head 202, etc., during the operation of forming the raised portion 52 and the upper decorative portion 54. In this case, the control unit 110 (see Figure 1) in the printing apparatus 12 controls the operation of the movement drive unit 106 regarding the stacking direction movement based on the information stored in the information storage unit 108 (see Figure 1). As explained above, in this example, the information storage unit 108 stores layer thickness information, which indicates the thickness of the ink layer, in correspondence with the layer formation conditions, which are the conditions for forming the ink layer. In this case, the information storage unit 108 stores layer thickness information in correspondence with the ink set used to form the ink layer and the type of ink layer, as shown in Figure 3, for example.

[0032] Figure 3 shows an example of the information stored in the information storage unit 108. In this example, the inkjet head 202 could be configured to eject multiple types of ink with different characteristics. In this case, for example, the user could select ink from a combination of inks provided as an ink set, according to the quality required for the printed material to be created, thereby using multiple types of ink with different characteristics to suit the printed material to be created. In this case, the inkjet head 202 could also be considered capable of ejecting ink contained in an ink set selected from multiple different ink sets. In this case, for example, the thickness of the ink layer formed using the ink could change depending on the characteristics of the ink used. Therefore, in this example, the information storage unit 108 stores layer thickness information in association with the ink sets usable by the inkjet head 202. In this case, the information storage unit 108 stores layer thickness information for each ink set, as shown in the figure as layer thickness, for multiple types of ink sets, such as Set A and Set B shown in the figure. In this case, the information storage unit 108 can be thought of as storing multiple layer thickness information corresponding to multiple types of ink. Furthermore, even when using ink from the same ink set, differences in the ink used to form the ink layers may result in differences in the thickness of the ink layers. For example, as explained above, the 4C layer may be a thicker ink layer compared to the white layer, color layer, etc. Therefore, in this example, the information storage unit 108 stores layer thickness information for each type of ink layer, distinguishing them as 4C, color, W, CL, etc. in the figure, with respect to the ink layers formed using the same ink set. In this case, the character 4C in the figure corresponds to a 4C layer such as the 4C layer 162 (see Figure 2) explained using Figure 2. The character color corresponds to a color layer such as the color layer 154 (see Figure 2) shown in Figure 2. The character W corresponds to a white layer such as the white layer 152 and white layer 164 (see Figure 2) shown in Figure 2. Furthermore, the letter CL corresponds to, for example, the clear layer, which is a layer of ink formed using only clear ink.In this case, the information storage unit 108 stores corresponding layer thickness information for each type of ink layer, for example, as shown in the film thickness column in the figure. The information storage unit 108 may also store layer thickness information for ink layers of other types. For example, the information storage unit 108 may further store layer thickness information for a primer layer.

[0033] Here, the ink set used and the type of ink layer can be considered to indicate, for example, the conditions for forming the ink layer. Therefore, in this example, the ink set used and the type of ink layer can be considered as examples of layer formation conditions. Also, as explained above, in this example, the white layer 152, etc., is an ink layer formed with one color of ink. The 4C layer 162, on the other hand, is an ink layer formed using multiple colors of ink. In this case, it can be considered that the way the inkjet head 202 is used is different when forming the 4C layer 162 and when forming the white layer 152, etc. Also, in this case, it can be considered that the information storage unit 108 stores multiple layer thickness information corresponding to multiple layer formation conditions in which the way the inkjet head 202 is used differs from each other when forming the ink layers. Furthermore, in this case, the operation of the head unit 102 (see Figure 1) that forms an ink laminate including the white layer 152 and the 4C layer 162 can be considered as an operation to form multiple ink layers, for example, by stacking an ink layer formed under a first layer formation condition and an ink layer formed under a second layer formation condition different from the first layer formation condition. More specifically, as explained above, in this example, the head unit 102 has multiple nozzle rows. And, for example, the number of nozzle rows used can be considered to be different when forming the 4C layer 162 and when forming the white layer 152. Therefore, in this case, the information storage unit 108 can be considered to store multiple layer thickness information corresponding to multiple layer formation conditions in which the number of nozzle rows used to form the ink layers is different from each other. Also, in this case, the first layer formation condition and the second layer formation condition can be considered as conditions in which the number of nozzle rows used to form the ink layers is different, for example. In this case, by using the layer thickness information stored in the information storage unit 108, the head unit 102 can be appropriately moved in the stacking direction, even when stacking multiple ink layers in which the number of nozzle rows used when forming the ink layers differs from one another.

[0034] Furthermore, the print head 102 in this example can be considered to have, for example, multiple nozzle rows that eject inks of different colors. In this case, if the conditions for forming the white layer 152, etc., are considered as the first layer formation conditions, then the first layer formation conditions can be considered, for example, as the conditions for forming an ink layer using only one predetermined color of ink. Also, in this case, if the conditions for forming the 4C layer 162 are considered as the second layer formation conditions, then the second layer formation conditions can be considered, for example, as the conditions for forming an ink layer using N predetermined colors (where N is an integer of 2 or more) of ink. When focusing on the number of ink colors used to form the ink layer, for example, even if ink is ejected at the density of solid printing from the nozzle row used to form the layer, the thickness of the ink layer may not necessarily be proportional to the number of ink colors used. More specifically, considering the first and second layer formation conditions as described above, regarding the relationship between the thickness of the ink layer formed under the second layer formation condition and the thickness of the ink layer formed under the first layer formation condition, for example, the thickness corresponding to the second layer formation condition may not simply be N times the thickness corresponding to the first layer formation condition, but may be smaller than N times the thickness. Therefore, in this case, the thickness of the ink layer indicated by the layer thickness information corresponding to the second layer formation condition may be made smaller than, for example, N times the thickness of the ink layer indicated by the layer thickness information corresponding to the first layer formation condition. In this example, as described above, by storing layer thickness information for each type of ink layer in the information storage unit 108, even in such cases, the head unit 102 can be appropriately moved in the stacking direction. Also, in this case, regarding the layer thickness information corresponding to an ink layer formed with multiple colors of ink, such as the 4C layer 162, it can be considered that, for example, it indicates a thickness smaller than the sum of the thicknesses of the ink layers formed with one color (monochromatic) corresponding to these multiple colors. More specifically, in this example, the thickness indicated by the layer thickness information for the 4C layer 162 can be considered to be smaller than, for example, the sum of the thicknesses of the ink layers formed by each of the YMCK colors.In this case, the thickness indicated by the layer thickness information for the 4C layer 162 can also be considered to be less than four times the thickness of the ink layer formed in a single color (the thickness of one layer).

[0035] Furthermore, regarding the differences in ink layer types, for example, it can be considered that these correspond to different layer formation conditions where the ink used to form the ink layer is different. Therefore, regarding the information storage unit 108, it can be considered that it stores multiple layers of thickness information corresponding to multiple layers of layer formation conditions where the ink used to form the ink layer is different from each other. In this case, regarding the layer formation conditions, the difference in the ink used to form the ink layer can be considered, for example, that at least some of the inks used to form the ink layer are different in color. Furthermore, regarding the difference in the ink used to form the ink layer, it can be considered that, for example, the combination of ink colors used when forming the ink layer is different. Furthermore, in this case, regarding the information storage unit 108 storing layer thickness information corresponding to the various types of ink layers described above, it can be considered that, for example, it stores information that is different from the layer thickness information corresponding to other ink colors as layer thickness information corresponding to at least some of the ink colors. In this case, regarding the difference in layer thickness information, it can be considered that, for example, the thickness of the ink layer indicated by the layer thickness information is different. Furthermore, regarding the first and second layer formation conditions, for example, they can be considered to be conditions where the ink used to form the ink layer is different from each other. With this configuration, for example, even when stacking layers of ink formed with different colored inks, the head unit 102 can be appropriately moved in the stacking direction. Also, even if the number of ink colors used is the same, differences in ink color may result in variations in the thickness of the ink layers. Therefore, it is preferable that the information storage unit 108 stores layer thickness information for each ink color, at least for some of the colors, even for ink layers formed with only one color of ink. Furthermore, in the printing apparatus 12, it is conceivable to use multiple types of inkjet heads 202 with different characteristics. In this case, for example, the inkjet heads 202 attached to the printing apparatus 12 can be appropriately replaced depending on the quality required for the printed material to be created. In this case, it is conceivable that the thickness of the ink layers formed using the inkjet head 202 may change depending on the characteristics of the inkjet head 202 used.Therefore, in this case, the information storage unit 108 may store, for example, multiple layers of thickness information corresponding to multiple types of inkjet heads 202.

[0036] As explained above, in this example, the movement drive unit 106 causes the head unit 102 to perform a main scanning operation, a sub-scanning operation, and stacking direction movement in accordance with the control unit 110 (see Figure 1), thereby causing the head unit 102 to form multiple ink layers on the medium 50. In this case, the control unit 110 causes the head unit 102 to form multiple ink layers by controlling the operation of the head unit 102 and the movement drive unit 106 based on, for example, a layer formation condition associated with one of the layer thickness information in the information storage unit 108. Regarding the control of the head unit 102 and the movement drive unit 106 by the control unit 110, forming multiple ink layers based on the layer formation condition can be considered as, for example, forming individual ink layers based on one of the layer formation conditions while forming multiple ink layers. In this case, the control unit 110 controls the stacking direction movement operation that the movement drive unit 106 causes the head unit 102 to perform, based on, for example, the layer thickness information stored in the information storage unit 108 associated with the layer formation condition. More specifically, in this case, the control unit 110 controls the movement of the head unit 102 in the stacking direction based on layer thickness information associated with, for example, the ink set and the type of ink layer used to form the ink layer. With this configuration, the head unit 102 can be appropriately made to move in the stacking direction according to, for example, the ink used in the head unit 102 and the type of ink layer to be formed. Furthermore, when various types of inkjet heads 202 are used in the printing apparatus 12, it is preferable that the control unit 110 controls the operation of the movement drive unit 106 related to stacking direction movement based on, for example, layer thickness information corresponding to the inkjet head 202 used to form the ink layer.

[0037] Furthermore, in this example, by using layer thickness information, the head unit 102 can be appropriately moved in the stacking direction according to the height of the ink layers to be stacked. This also allows the printing apparatus 12 to appropriately stack and form a large number of ink layers on the medium 50. In this example, the control unit 110 causes the head unit 102 to stack and form, for example, 50 or more layers of ink. With this configuration, for example, a stack of ink that is convex relative to the surface of the medium 50 can be appropriately formed on the medium 50. The control unit 110 may cause the head unit 102 to form even more ink layers. For example, the control unit 110 may cause the head unit 102 to stack and form 100 or more layers of ink. Furthermore, regarding the relationship between the thickness of individual ink layers and the height of the stacked ink layers, in this example, the thickness of one ink layer is, for example, about 10 to 30 μm. In this case, regarding the height of the stacked ink layers, it can also be considered that, for example, the height per layer is about 10 to 30 μm. The control unit 110 may, for example, cause the print head unit 102 to form multiple ink layers such that their height on the medium 50 is 1 cm or more.

[0038] Next, we will explain in more detail the stacking direction movement that the moving drive unit 106 causes the head unit 102 to perform, and the control that the control unit 110 performs on the moving drive unit 106 regarding the stacking direction movement. In this example, the control unit 110 controls the operation of the head unit 102 and the moving drive unit 106 to cause the head unit 102 to perform multiple stacking direction movements while forming at least one ink layer in between. In this case, the control unit 110's control of the moving drive unit 106 can be considered, for example, as a control that links the stacking of ink layers with the stacking direction movement. Also in this example, the control unit 110 controls the stacking direction movement that the moving drive unit 106 causes the head unit 102 to perform based on the layer thickness information stored in the information storage unit 108. In this case, as a method of controlling the stacking direction movement, for example, it is conceivable to make the amount of movement in a single stacking direction movement variable based on the layer thickness information. More specifically, when the stacking direction movement distance is made variable, the control unit 110 determines the stacking direction movement distance, which is the distance the head unit 102 moves relative to the medium in one stacking direction movement, based on, for example, layer thickness information corresponding to the layer formation conditions. With this configuration, for example, when the stacking direction movement distance is made variable, the stacking direction movement distance can be appropriately determined in accordance with the height of the ink layers to be stacked. In this case, for example, the control unit 110 determines the stacking direction movement distance for the later of two consecutive stacking direction movements based on layer thickness information corresponding to the layer formation conditions used when forming the ink layer formed between the two stacking direction movements. With this configuration, for example, the head unit 102 can be appropriately made to perform stacking direction movements in accordance with the height of the ink layers to be stacked. Furthermore, this makes it possible to appropriately form ink stacks of various configurations on the medium 50.

[0039] Furthermore, when the stacking direction movement distance is variable, the control unit 110 causes the head unit 102 to move in the stacking direction each time a preset number of ink layers are formed. The control unit 110 causing the head unit 102 to move in the stacking direction can be thought of as, for example, the control unit 110 controlling the operation of the movement drive unit 106, which in turn causes the movement drive unit 106 to move in the stacking direction. With this configuration, for example, the head unit 102 can be made to move in the stacking direction at regular intervals. Also, the timing of the head unit 102's stacking direction movement can be variable. In this case, for example, the control unit 110 causes the head unit 102 to move in the stacking direction when the change in the height of the stacked ink layers reaches a predetermined amount. In this case, the movement drive unit 106 can be thought of as causing the head unit 102 to move in the stacking direction each time the increase in the height of the ink layers reaches a predetermined amount. Furthermore, the stacking direction movement distance can be set to a preset constant distance, for example. As a fixed distance for movement in the stacking direction, for example, a distance corresponding to a value selected from a plurality of pre-prepared default values ​​can be used. Also, when the movement distance in the stacking direction is set to a fixed distance, the control unit 110 determines the timing for movement in the stacking direction based on, for example, layer thickness information corresponding to the layer formation conditions used when forming the layers of ink to be stacked. In addition, the control unit controls the operation of the movement drive unit 106 so that, for example, movement in the stacking direction is selectively performed at the timing when some of the ink layers have been formed, in accordance with the height of the ink layers to be stacked. Even with this configuration, for example, the head unit 102 can be appropriately made to move in the stacking direction in accordance with the height of the ink layers to be stacked.

[0040] Furthermore, as described above, the stacking direction movement distance can be made variable or fixed. In either case, in the operation of forming multiple ink layers, it is preferable that the distance between the formed ink layer and the inkjet head 202 be within a predetermined range. In this case, the distance between the ink layer and the inkjet head 202 can be considered, for example, the distance between the top surface of the ink layer and the surface on the inkjet head 202 where the nozzle is formed (nozzle surface). More specifically, in this example, with respect to the operation of forming multiple layers of ink, if the distance between the formed layer and the inkjet head 202 at the timing when the formation of a new ink layer on top of an already stacked ink layer is started is defined as the layer-head distance, then the control unit 110 determines, for example, the timing at which to perform stacking direction movement so that the layer-head distance is within a predetermined range. In this case, the moving drive unit 106, in response to the control unit 110, causes the head unit 102 to move in the stacking direction, for example, after at least some ink layers have been formed and before the formation of the next ink layer begins, so that the distance between the layer heads is within a preset range. With this configuration, for example, the distance between the layer heads during the formation of ink layers can be kept within an appropriate range. This also allows for the proper formation of ink layers. Furthermore, in this case, the stacking direction movement can be considered to be performed as appropriate, for example, when the distance between the layer heads narrows, rather than necessarily every time a certain number of ink layers are formed. In this case, for example, the number of ink layers formed by the head unit 102 between two consecutive stacking direction movements can be considered to be variable. More specifically, for example, if the number of ink layers formed by the head unit 102 between two consecutive stacking direction movements is defined as the number of layers between stacking direction movements, the number of layers between stacking direction movements after the first stacking direction movement (which is one of the stacking direction movements) may be different from the number of layers between stacking direction movements after the second stacking direction movement (which is one of the stacking direction movements different from the first).With this configuration, for example, the head unit 102 can be appropriately moved in the stacking direction when necessary.

[0041] Furthermore, regarding causing the head unit 102 to move in the stacking direction when necessary, if the stacking direction movement distance is kept constant, it is conceivable to cause the head unit 102 to move in the stacking direction, for example, as shown in Figures 4 and 5. Figures 4 and 5 illustrate examples of the timing for causing the head unit 102 to move in the stacking direction. Figures 4(a) to (c) and 5(a) to (c) show examples of ink layers formed on the medium 50 together with the inkjet head 202 in the head unit 102. More specifically, Figure 4 shows an example of the operation of forming ink layers with a thickness of 20 μm each, when the stacking direction movement distance is 100 μm. In this case, the stacking direction movement distance of 100 μm is, for example, the minimum value of the stacking direction movement distance that can be adjusted in the printing device 12 (the minimum adjustable height). The minimum value of the stacking direction movement distance is, for example, the smallest distance among the predetermined values ​​of stacking direction movement distances that have been prepared in advance. Furthermore, in this case, the relationship between the thickness of the ink layer and the stacking direction movement distance shown in Figure 4 can be considered, for example, as an example where the thickness of one ink layer is less than 50% of the minimum adjustable height. In this case, from the perspective of reducing the frequency of stacking direction movement, for example, it is conceivable to form multiple ink layers by stacking them without performing stacking direction movement while there is clearance between the inkjet head 202 and the printer. In this case, for example, n < minimum adjustable height / thickness of one layer ≤ n+1 For a positive integer n that satisfies the condition, it is conceivable to cause the head unit 102 to move in the stacking direction each time n layers of ink are formed. With this configuration, for example, the head unit 102 can be made to move appropriately in the stacking direction. It is also conceivable to cause the head unit 102 to move in the stacking direction so that, for example, the distance between layer heads does not exceed a preset maximum value. In this case, for example, as shown in Figures 4(a) to (c), the head unit 102 is made to move in the stacking direction each time an ink layer is formed, as long as the distance between layer heads does not exceed the maximum value even after the next stacking direction movement. In this case, if the distance between layer heads exceeds the maximum value even after the next stacking direction movement, the head unit 102 is made to form the next ink layer without causing a stacking direction movement. With this configuration as well, for example, the head unit 102 can be made to move appropriately in the stacking direction.

[0042] Figure 5 also shows an example of the operation of stacking ink layers with a thickness of 70 μm each, assuming a stacking direction movement distance of 100 μm. In this case, the relationship between the thickness of the ink layers and the stacking direction movement distance shown in Figure 5 can be considered as an example where, for example, the thickness of one ink layer is 50% or more of the minimum adjustable height. In this case, immediately after starting the stacking of ink layers on the medium 50, it is necessary to make the head unit 102 move in the stacking direction each time an ink layer is formed, as shown in Figures 5(a) to (c). However, even in this case, after a certain number of ink layers have been formed, there will be a timing when the next ink layer can be formed without stacking direction movement. Therefore, in this case, for example, it is conceivable to basically make the head unit 102 move in the stacking direction each time an ink layer is formed, but when certain conditions occur, to make the head unit 102 form the next ink layer without stacking direction movement. In this case, forming the next ink layer on the head unit 102 without moving in the stacking direction can be considered, for example, by stopping the stacking direction movement once. More specifically, in this case, for example, when the nth ink layer (where n is a positive integer) is formed, (n × distance traveled in the stacking direction) - (n × thickness of one layer) > thickness of one layer × 120% In such a case, it is possible to stop the stacking direction movement once. With this configuration, for example, when the thickness of one ink layer is 50% or more of the minimum adjustable height, the head unit 102 can be made to move appropriately in the stacking direction.

[0043] Next, we will provide supplementary explanations regarding the configuration described above, as well as explanations regarding variations. As explained above, in this example, the printing apparatus 12 forms a large number of ink layers on the medium 50. In this case, it takes a lot of time to create the printed material. In contrast, the moving drive unit 106 may, for example, reduce the number of printing passes when forming some of the ink layers. In this case, the number of printing passes can be considered as, for example, the number of times the inkjet head 202 passes over a position opposite to one position on the medium 50 when forming one ink layer. With this configuration, for example, the time required to create the printed material can be appropriately reduced. More specifically, as explained above, in this example, the head unit 102 forms, for example, an ink laminate having a raised portion 52 and an upper decorative portion 54 (see Figure 2) on the medium 50. In this case, in order to express a color image with high quality, it is desirable to increase the number of printing passes to a certain extent to form the ink layer, for example, the color layer 154 (see Figure 2) in the upper decorative layer 54. In contrast, for the ink layer in the raised portion 52, which is a multilayer portion where many ink layers overlap, reducing the number of printing passes usually does not significantly affect the quality of the printed material. Therefore, the number of printing passes when forming at least some of the ink layers in the raised portion 52 may be smaller than the number of printing passes when forming the color layer 154. In this case, for example, the number of printing passes when forming the 4C layer 162 (see Figure 2) in the raised portion 52 may be smaller than the number of printing passes when forming the color layer 154. With this configuration, for example, the raised portion 52 can be formed appropriately in a short time. In addition, this can appropriately reduce the time required to create the printed material. The number of printing passes when forming the ink in the raised portion 52 may be, for example, 1 pass. In this case, reducing the number of passes to one can be thought of as, for example, forming a layer of ink without making any passes.

[0044] Furthermore, as described above, in this example, the moving drive unit 106 causes the head unit 102 to form multiple ink layers while performing appropriate movement in the stacking direction between layers. In this case, the moving drive unit 106 causes the head unit 102 to move in the stacking direction each time, for example, 1 to 10 ink layers are formed. With this configuration, for example, the head gap can be appropriately adjusted in accordance with the progress of ink layer stacking. In addition, this makes it possible to appropriately form printed materials with a stack of inks that forms a convex shape on the surface of the medium 50. In this case, the printing device 12 can be used to create printed materials that include Braille, for example. Furthermore, regarding the stack of inks, it is also possible to create printed materials with an uneven surface by varying the number of ink layers stacked depending on the position. In this case, for example, it is possible to create printed materials that reproduce the colors and surface shape of an oil painting.

[0045] Furthermore, the operation of creating printed materials in this example may, at first glance, seem similar to the operation of creating three-dimensional objects with a 3D printer. However, in this example, by stacking layers of ink on the medium 50, it is possible to create printed materials with a different design from, for example, objects created with a 3D printer. Also, when creating objects with an inkjet head in a 3D printer, layers of ink of a predetermined thickness are usually stacked to form the object. In this case, a flattening mechanism such as a roller is usually used to adjust the thickness of the ink layers with high precision. In contrast, in this example, the printing device 12 forms ink layers without flattening the ink layers with a roller. In addition, the printing device 12 may also form layers of ink with different thicknesses, such as the 4C layer and white layer described above. And in this example, with the configuration described above, multiple ink layers can be appropriately stacked and formed on the medium 50 even in such cases. More specifically, when forming only ink layers of a certain thickness, as in a 3D printer, or when flattening the ink layers using rollers, the travel distance in the stacking direction and the timing of the stacking direction movement can be kept constant. However, if the thickness of the ink layers to be formed cannot be considered constant, performing stacking direction movement in this manner can easily lead to inconsistencies between, for example, the actual height of the formed ink layers and the position of the inkjet head. In contrast, in this example, at least one of the travel distance in the stacking direction movement or the timing of the stacking direction movement is adjusted to match the actual thickness of the ink layers to be formed. Therefore, according to this example, even when stacking ink layers of various thicknesses without using a flattening mechanism such as rollers, the head unit 102 can be made to move appropriately in the stacking direction. In this case, the movement drive unit 106 may, for example, cause the head unit 102 to move in the stacking direction continuously at regular intervals each time a predetermined number of ink layers are formed. Furthermore, the moving drive unit 106 may, for example, not stop the stacking direction movement at predetermined timings, thereby intermittently causing the head unit 102 to move in the stacking direction.

[0046] Furthermore, regarding the difference between the operation of creating printed materials with the printing device 12 in this example and the operation of creating objects with a 3D printer, it is conceivable that support material may not be used in the case of the 3D printer, whereas support material may not be used in the case of the example. In this case, it can be assumed that the printed material created with the printing device 12 in this example will have, for example, an ink layer that does not form an overhang. Also, when creating objects with a 3D printer, by covering the area around the object being created with support material, it becomes possible, for example, for the already formed ink layer to be excessively exposed to ultraviolet light. In this case, for example, it is possible to appropriately prevent over-curing, where the ink hardens more than necessary, in areas of the object's surface that are visible to the observer (such as the colored area of ​​the surface). On the other hand, in the case of the example, depending on the characteristics of the ink used, it is conceivable that, for example, excessive ultraviolet light may be exposed to the ink layer, causing the problem of over-curing. More specifically, in this example, when multiple inks are layered to form a thick, built-up surface, the first layer of ink to be formed may be exposed to ultraviolet light during the formation of subsequent layers. Depending on the characteristics of the inks used, this could lead to over-curing. This problem is particularly likely to occur when translucent inks, such as clear inks, are layered. When over-curing occurs, the quality of the printed material may deteriorate. Therefore, in such cases, it is preferable to form the multiple ink layers using a method that minimizes the risk of over-curing.

[0047] In this regard, as explained above, in this example, the printing apparatus 12 first forms the raised portion 52, which is a multilayer portion, and then forms an upper decorative portion 54 having a color layer 154 on top of it. With this configuration, for example, the problem of over-hardening in the color layer 154, which is an important ink layer for expressing the design of the printed material, can be appropriately prevented. In addition, this makes it possible to appropriately produce high-quality printed materials. Furthermore, over-hardening can be addressed by adjusting the intensity (e.g., illuminance) of the ultraviolet light emitted by the ultraviolet light source 204 (see Figure 1). In this case, for example, regarding the intensity of the ultraviolet light emitted by the ultraviolet light source 204, it is conceivable to reduce the intensity of the ultraviolet light for the ink layers below the topmost ink layer, and then increase the intensity of the ultraviolet light only when forming the ink layer near the top. More specifically, for example, if the uppermost layer of ink, which is formed by stacking multiple ink layers by the print head 102, is defined as the upper layer, and the ink layers other than the upper layer are defined as the lower layer, then when forming the upper layer, the control unit 110 (see Figure 1) causes the print head 102 to perform a main scanning operation while irradiating the UV light source 204 with ultraviolet light at a preset first intensity. Then, when forming the lower layer, the control unit 110 causes the print head 102 to perform a main scanning operation while irradiating the UV light source 204 with ultraviolet light at a second intensity weaker than the first intensity. With this configuration, problems such as over-curing in the lower ink layers can be appropriately prevented. In this case, the second intensity can be considered as, for example, an intensity that does not completely cure the ink during the main scanning operation that forms the ink layer. Not completely curing the ink can be considered as, for example, not reaching the cumulative light amount necessary to complete the curing of the ink. The total amount of light required to complete the curing of the ink can be determined by considering, for example, the total amount of light specified in the ink's specifications. In this case, the lower layers of ink can be properly cured by, for example, further irradiation with ultraviolet light during the formation of the upper layers of ink.Furthermore, when forming the upper layer of ink, stronger ultraviolet light can be irradiated to properly cure the ink layer, for example. Also, as explained above, in this example, the head unit 102 forms an ink laminate having, for example, a raised portion 52 and an upper decorative portion 54 on the medium 50. In this case, the upper decorative portion 54 can be considered, for example, an example of the upper portion described above. Also, the raised portion 52 can be considered, for example, an example of the lower portion described above. Also, in this case, as explained above, the upper decorative portion 54 has, for example, a white layer and a color layer. Such a configuration can be considered, for example, a configuration in which the raised portion 52 is formed in advance to form an ink laminate, and then the white layer and color layer are formed afterward. In this case, by forming the white layer on top of the raised portion 52, for example, the influence of the strong ultraviolet light used when forming the upper decorative portion 54 on the ink layer in the raised portion 52 can be reduced. Therefore, this configuration allows for the proper creation of high-quality printed materials while more effectively preventing issues such as over-hardening of the ink layer.

[0048] Furthermore, regarding objects created with a 3D printer, for example, when creating a colored object, it is usually necessary to color the object assuming that it will be observed from all directions. In this case, for example, it is necessary to color the outer periphery corresponding to the sides of the object for all the layers of ink that are stacked. In contrast, the printed material created in this example can be considered to be observed from above the stacked ink layers. Therefore, in this example, for example, the 4C layer 162 or the white layer 164 (see Figure 2) described above can be appropriately used as the ink layers stacked in the raised portion 52. And in this case, it can be said that the coloring method for the printed material created in this example is different from that of an object created with a 3D printer. Also, when coloring the sides of the stacked ink layers with high precision, as is the case with objects created with a 3D printer, it is usually necessary to control the thickness of the ink layers with high precision. Therefore, as explained above, in this case, it is usually necessary to flatten the ink layer using a flattening mechanism such as a roller. In addition, in this case, for example, it may be necessary to surround the entire perimeter of the ink layer with support material in order to align the surface of the sides of the ink layer. In contrast, in this example, due to the difference in coloring method as described above, it is possible to appropriately create a printed material with layered ink without using a flattening mechanism such as a roller or support material.

[0049] Furthermore, when flattening ink layers using a flattening mechanism such as a roller, as is done when creating objects with a 3D printer, it is usually necessary to adjust the head gap according to the thickness of the ink layers after each predetermined number of ink layers have been formed. More specifically, in the case of a 3D printer, the head gap is usually widened by a fixed distance, determined according to the thickness of one ink layer, after each ink layer has been formed. In contrast, as can be understood from the matters explained above, in this example, the timing of the head unit 102's movement in the stacking direction and the distance of the stacking direction movement in one stacking direction movement can be set more flexibly. Therefore, according to this example, for example, various settings can be appropriately made regarding the number of layers between stacking direction movements. In addition, this allows the head unit 102 to move in the stacking direction appropriately at the timing when necessary. Also, in this case, for example, the stacking direction movement distance can be determined according to the thickness of the ink layers formed between two stacking direction movements, if necessary. Furthermore, in this example, the ability to flexibly set the timing of the stacking direction movement makes it possible to stack multiple ink layers of different thicknesses and to use various types of ink without using a flattening mechanism such as a roller. More specifically, as explained above, when forming ink layers without using a flattening mechanism, the thickness of the ink layers can be considered to vary depending on, for example, the color and type of ink used to form the ink layers. In this case, if the head unit 102 is made to move in the stacking direction by a fixed distance every time a certain number of ink layers are formed, inconsistencies are likely to occur between the actual height of the formed ink layers and the position of the inkjet head. In contrast, in this example, by controlling the operation of the stacking direction movement based on the layer thickness information stored in the information storage unit 108, the head unit 102 can be made to move in the stacking direction more appropriately in accordance with the thickness of the ink layers to be stacked on the medium 50.

[0050] Furthermore, in this regard, in the configuration of the example described above, it can be assumed that the control of the stacking direction movement is mainly performed by the control unit 110 in the printing device 12. In this case, the control unit 110 controls the stacking direction movement based on the layer thickness information stored in the information storage unit 108 in the printing device 12. In this case, the configuration of the example can be considered as a configuration in which the printing device 12 controls the stacking direction movement by itself. In contrast, in a modified configuration of the printing system 10, it is also possible to use a configuration where the information storage unit 108 is located outside the printing device 12, for example. In this case, it is also possible that the timing of the stacking direction movement and the distance of the stacking direction movement are determined by the control device 14 (see Figure 1). In this case, the control unit 110 of the printing device 12 receives instructions from the control device 14 to specify, for example, the timing of the stacking direction movement and the distance of the stacking direction movement, and based on these instructions, controls the stacking direction movement that the movement drive unit 106 causes the head unit 102 to perform. Such a configuration can be considered, for example, as one in which the printing device 12 controls the movement in the stacking direction based on instructions from the control device 14. In this case, the control device 14 controls the movement in the stacking direction of the printing device 12 by, for example, sending a predetermined command to the printing device 12. Furthermore, in a further modification of the configuration of the printing system 10, the control unit 110 or the control device 14 may determine the timing and distance of the movement in the stacking direction without using, for example, layer thickness information. In this case, the printing device 12 further includes a sensor that detects, for example, the height of the ink layers stacked on the medium 50. For example, an infrared sensor could be used as such a sensor. In this case, the control unit 110 or the control device 14 of the printing device 12 determines the timing and distance of the movement in the stacking direction based on the output of this sensor. Even with these configurations, for example, the head unit 102 can be made to move appropriately in the stacking direction according to the thickness of the ink layers stacked on the medium 50.

[0051] Furthermore, as described above, in this example, the printing system 10 comprises a printing device 12 and a control device 14. However, when considering the printing operation performed by the printing system 10, the combined configuration of the printing device 12 and the control device 14 described above can also be considered as a printing device. In this case, the printing device 12 can be considered, for example, as the main body of the printing device. Similarly, the control device 14 can be considered, for example, as a control unit located outside the main body. Moreover, the configuration of the printed material produced by the printing device 12 is not limited to the configuration described above and can be changed in various ways. More specifically, in this example, the printing device 12 forms an upper decorative layer 54 having a white layer 152 and a color layer 154 on top of a raised portion 52, for example, as shown in Figure 2. However, in a modified operation of the printing device 12, the printing device 12 may, for example, first form an ink layer corresponding to the color layer 154, and then form the raised portion 52 on top of it. In this case, for example, it is conceivable to form a raised portion 52 with a configuration of multiple clear layers formed with clear ink. In this case, the medium 50 may be, for example, a light-reflective medium such as white. Even with this configuration, it is possible to appropriately create printed materials in which a layer of ink that forms a convex shape on the surface of the medium 50 is formed. Furthermore, this makes it possible to appropriately create printed materials that express a variety of designs. In addition, when using a medium 50 of a color other than a light-reflective color, if necessary, a layer of ink corresponding to the white layer 152 may be formed below the layer of ink corresponding to the color layer 154.

[0052] Furthermore, the printing apparatus 12 may also form layers of ink that represent a color image, for example, within the raised portion 52. In this case, for example, each time a predetermined number of 4C layers 162 are formed as ink layers constituting the raised portion 52, the same or similar white and color layers as the white layer 152 and color layer 154 in the upper decorative portion 54 are formed. In this case, the head portion 102 forms the raised portion 52 by repeatedly forming the 4C layers 162, white layers, and color layers in this manner. For a raised portion 52 with such a configuration, it can also be considered as having a configuration in which the 4C layers 162 overlap with white and color layers sandwiched in between. In this case as well, for example, the upper decorative portion 54 is formed on top of the raised portion 52 to form the white layer 152 and color layer 154 at the top of the ink laminate. Even with this configuration, for example, a printed material with an ink laminate that is convex on the surface of the medium 50 can be appropriately produced. Furthermore, when the raised portion 52 is formed in this manner, it is conceivable that, for example, the color at the boundary of the color layer in the raised portion 52 may become dark and conspicuous. Therefore, in this case, the head portion 102 may, for example, form many small ink dots at the edges of the color layer in the raised portion 52 by ejecting a small amount of ink. Small ink dots can be thought of as, for example, ink dots formed by ejecting the minimum amount of ink when using an inkjet head 202 that has a variable ink ejection capacity in multiple stages. With this configuration, for example, it is possible to appropriately prevent the color at the boundary of the color layer in the raised portion 52 from becoming excessively dark.

[0053] Furthermore, in Figure 2 and other diagrams described above, for illustrative purposes, the ink layers stacked on the medium 50 were depicted as having a flat top surface. However, the actual ink stack 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 at the raised portion 52 depending on the location. In this case, during the operation of forming multiple ink layers constituting the ink stack, the movement drive unit 106 causes the head unit 102 to move in the stacking direction to match the highest position in the ink stack being formed. In this case, the highest position in the ink stack being formed can be considered, for example, the position where the most ink layers overlap. In this case, the head unit 102 forms multiple ink layers on the medium 50, for example, as shown in Figure 6.

[0054] Figure 6 shows an example of the configuration of an ink laminate with an uneven top surface. Figures 6(a) to 6(c) show various specific examples of the configuration of an ink laminate. More specifically, Figure 6(a) shows an example of a state where the top surface is uneven, in the case where a raised portion 52 is formed by stacking 4C layers as shown in Figure 2. In this case, the head unit 102 forms a raised portion 52 with an uneven top surface by stacking multiple 4C layers, for example, while varying the position of each 4C layer. The head unit 102 also forms an ink laminate with an uneven top surface on the medium 50 by forming an upper decorative portion 54 on such a raised portion 52. In this case, the head unit 102 forms, for example, one white layer and one color layer as the upper decorative portion 54. The head unit 102 may also further form a clear layer on top of the color layer in the upper decorative portion 54. Furthermore, the head portion 102 may be formed as a raised portion 52 by stacking, for example, layers of ink other than the 4C layer. In this case, the head portion 102 may be formed as a raised portion 52 by stacking, for example, clear layers as shown in Figure 6(b). In this case, the head portion 102 can be formed by stacking multiple clear layers, for example, by varying the position of each clear layer, to form a raised portion 52 with an uneven surface on top. The head portion 102 can then form, for example, an upper decorative portion 54 on such a raised portion 52 to form an ink laminate with an uneven surface on the medium 50. When forming a raised portion 52 with this configuration, the medium 50 can be, for example, a light-reflective colored medium. In this case, the head portion 102 may also form, for example, only a color layer as the upper decorative portion 54. Even with this configuration, by using a light-reflective colored medium 50, for example, the image expressed by the color layer can be appropriately viewed by the observer. Furthermore, when using a raised portion 52 formed by layering clear layers, the head portion 102 may first form a color layer corresponding to the upper decorative portion 54 on the medium 50, as shown in Figure 6(c), and then form the raised portion 52 on top of it. In this case as well, the head portion 102 forms a raised portion 52 with an uneven surface by layering multiple clear layers, for example, by varying the position where each clear layer is formed.Even with this configuration, for example, a laminate of ink with an uneven surface can be appropriately formed on the medium 50. In this case as well, for example, a light-reflective colored medium 50 can be used. [Industrial applicability]

[0055] The present invention can be suitably used, for example, in a printing apparatus. [Explanation of Symbols]

[0056] 10...Printing system, 102...Head unit, 104...Stand unit, 106...Movement drive unit, 108...Information storage unit, 110...Control unit, 12...Printing device, 14...Control device, 152...White layer, 154...Color layer, 162...4C layer, 164...White layer, 202...Inkjet head, 204...Ultraviolet light source, 50...Media, 52...Raised section, 54...Upper layer decoration 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 that ejects ink onto the aforementioned medium, A media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. 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 moving drive unit, Information storage unit for storing information used by the control unit and Equipped with, The aforementioned mobile drive unit is A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. The ink ejection unit performs this action. The information storage unit stores layer thickness information indicating the thickness of the ink layer in correspondence with the layer formation conditions, which are the conditions for forming the ink layer, and also stores a plurality of layers of layer thickness information corresponding to different layer formation conditions. The control unit, By controlling the operation of the ink ejection unit and the moving drive unit based on the layer formation conditions associated with any of the layer thickness information, the ink ejection unit is made to form the multiple ink layers. and, A printing apparatus characterized in that the moving drive unit controls the operation of the stacking direction movement performed by the ink ejection unit based on the layer thickness information corresponding to the layer formation conditions.

2. The ink ejection unit has an ejection head for ejecting ink, The information storage unit stores the plurality of layer thickness information corresponding to the plurality of layer formation conditions in which the method of using the ejection head during the formation of the ink layer differs from one another. The aforementioned ink ejection unit is The ink layer formed under the first layer formation conditions, The ink layer formed under the second layer formation conditions, which are different from the first layer formation conditions, The printing apparatus according to claim 1, characterized in that it forms multiple layers of the aforementioned inks by stacking them.

3. The discharge head has a nozzle row in which multiple nozzles are arranged, The ink ejection unit has a plurality of nozzle rows, The information storage unit stores the plurality of layer thickness information corresponding to the plurality of layer formation conditions in which the number of nozzle rows used to form the ink layer is different from each other. The printing apparatus according to claim 2, characterized in that the first layer formation condition and the second layer formation condition are conditions in which the number of nozzle rows used to form the ink layer is different.

4. The ink ejection unit has a plurality of nozzle rows that eject ink of different colors from each other. The first layer formation condition is the condition for forming the ink layer using only one predetermined color of ink, The second layer formation condition is the condition for forming the ink layer using a predetermined N color (where N is an integer of 2 or more) of ink, The printing apparatus according to claim 3, characterized in that the thickness of the ink layer indicated by the layer thickness information corresponding to the second layer formation condition is less than N times the thickness of the ink layer indicated by the layer thickness information corresponding to the first layer formation condition.

5. The discharge head has a nozzle row in which multiple nozzles are arranged, The ink ejection unit has a plurality of nozzle rows that eject ink of different colors from each other. The aforementioned information storage unit is The system stores information on multiple layer thicknesses corresponding to multiple layer formation conditions in which the inks used to form the ink layers are different from each other, and stores information that is different from the information on the other ink colors as the information on the layer thicknesses corresponding to at least some of the ink colors. The printing apparatus according to claim 2, characterized in that the first layer formation condition and the second layer formation condition are conditions in which the ink used to form the ink layer is of a different color.

6. The control unit, The stacking direction movement distance, which is the distance the ink ejection unit moves relative to the medium in one stacking direction movement, is determined based on the layer thickness information corresponding to the layer formation conditions, and the ink ejection unit is made to perform multiple stacking direction movements while forming at least one layer of ink in between. The printing apparatus according to claim 1, further characterized in that, of two consecutive stacking direction movements, the stacking direction movement distance for the later of the two consecutive stacking direction movements is determined based on the layer thickness information corresponding to the layer formation conditions used when forming the ink layer formed between the two stacking direction movements.

7. The stacking direction movement distance, which is the distance the ink ejection unit moves relative to the medium in one stacking direction movement, is a predetermined constant distance. The printing apparatus according to claim 1, characterized in that the control unit determines the timing for performing the stacking direction movement based on the layer thickness information corresponding to the layer formation conditions used when forming the layers of ink to be stacked.

8. The ink ejection unit has an ejection head for ejecting ink, The printing apparatus according to claim 1, characterized in that, when the distance between the formed layer and the ejection head at the timing of starting to form a new layer of the ink on top of the already stacked layer of ink is defined as the layer-head distance, the moving drive unit causes the ink ejection unit to move in the stacking direction so that the layer-head distance becomes a distance within a preset range.

9. If the number of ink layers formed by the ink ejection unit between two consecutive stacking direction movements is defined as the number of layers between stacking direction movements, The printing apparatus according to claim 8, characterized in that the number of layers between stacking direction movements after the first stacking direction movement, which is any of the stacking direction movements, is different from the number of layers between stacking direction movements after the second stacking direction movement, which is any of the stacking direction movements different from the first.

10. The ink ejection unit has an ejection head for ejecting ink, The aforementioned ejection head is capable of ejecting multiple types of inks, each with different characteristics. The information storage unit stores the multiple layer thickness information corresponding to the multiple types of ink, The printing apparatus according to claim 1, characterized in that the control unit controls the movement of the ink ejector unit to perform the stacking direction movement based on the layer thickness information corresponding to the ink used in the ejection head.

11. The printing apparatus according to claim 1, characterized in that the control unit causes the ink ejection unit to form a plurality of ink layers of 50 or more layers on top of each other, thereby forming a laminate of ink that is convex with respect to the surface of the medium on the medium.

12. 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 causes the ink ejection unit to perform the main scanning operation while irradiating the ultraviolet light source with ultraviolet light, thereby forming a layer of ink in the ink ejection unit. If, among the multiple layers of ink stacked by the ink ejection unit, a predetermined number of ink layers at the top are defined as the upper layer, and the ink layers other than the upper layer are defined as the lower layer, During the formation of the upper layer, the control unit causes the ink ejection unit to perform the main scanning operation while irradiating the ultraviolet light source with ultraviolet light at a preset first intensity. The printing apparatus according to claim 1, characterized in that, when forming the lower layer, the control unit causes the ink ejection unit to perform the main scanning operation while irradiating the ultraviolet light source with ultraviolet light at a second intensity weaker than the first intensity.

13. 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 that ejects ink onto the aforementioned medium, A media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. A movement drive unit causes the ink ejection unit to perform a movement operation relative to the medium, An information storage unit for storing information used to control the operation of the ink ejection unit and the mobile drive unit. Using, The aforementioned moving drive unit, A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. The ink ejection unit performs this action. The information storage unit stores layer thickness information indicating the thickness of the ink layer in correspondence with the layer formation conditions, which are the conditions for forming the ink layer, and also stores a plurality of layers of layer thickness information corresponding to different layer formation conditions. By controlling the operation of the ink ejection unit and the moving drive unit based on the layer formation conditions associated with any of the layer thickness information, the ink ejection unit is made to form the multiple ink layers. and, A printing method characterized in that the moving drive unit controls the operation of the stacking direction movement performed by the ink ejection unit based on the layer thickness information corresponding to the layer formation conditions.

14. 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 media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. 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 aforementioned mobile drive unit is A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. The ink ejection unit performs this action. 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 causes the ink ejection unit to perform the main scanning operation while irradiating the ultraviolet light source with ultraviolet light, thereby forming a layer of ink in the ink ejection unit. If, among the multiple layers of ink stacked by the ink ejection unit, a predetermined number of ink layers at the top are defined as the upper layer, and the ink layers other than the upper layer are defined as the lower layer, During the formation of the upper layer, the control unit causes the ink ejection unit to perform the main scanning operation while irradiating the ultraviolet light source with ultraviolet light at a preset first intensity. A printing apparatus characterized in that, when forming the lower layer, the control unit irradiates the ultraviolet light source with ultraviolet light at a second intensity weaker than the first intensity, while causing the ink ejection unit to perform the main scanning operation.

15. 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 that ejects ink onto the aforementioned medium, A media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. 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, A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. The ink ejection unit performs this action. 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, By irradiating the aforementioned ultraviolet light source with ultraviolet light and causing the ink ejection unit to perform the main scanning operation, a layer of the ink is formed in the ink ejection unit. If, among the multiple layers of ink stacked by the ink ejection unit, a predetermined number of ink layers at the top are defined as the upper layer, and the ink layers other than the upper layer are defined as the lower layer, During the formation of the upper layer, the main scanning operation is performed on the ink ejection unit while the ultraviolet light source is irradiated with ultraviolet light at a preset first intensity. A printing method characterized in that, when forming the lower layer, the main scanning operation is performed on the ink ejection unit while irradiating the ultraviolet light source with ultraviolet light at a second intensity weaker than the first intensity.

16. 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 an ejection head for ejecting ink onto the aforementioned medium, A media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. A movement drive unit causes the ink ejection unit to perform a movement operation that moves relative to the medium. Equipped with, The aforementioned mobile drive unit is A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. By having the ink ejection unit perform this action, multiple layers of the ink are formed by stacking them. A printing apparatus characterized in that, when the distance between the formed layer and the ejection head at the timing when the formation of a new layer of ink begins on the already stacked layer of ink is defined as the layer-head distance, the moving drive unit causes the ink ejection unit to move in the stacking direction so that the layer-head distance becomes a distance within a preset range.

17. 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 an ejection head for ejecting ink onto the aforementioned medium, A media holding portion is provided on an opposing surface which is the surface facing the ink ejection portion, and a media holding portion is provided on the opposing surface which is the surface facing the ink ejection portion. 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, A main scanning operation in which ink is ejected while moving relative to the medium in a preset main scanning direction, By moving at least one of the ink ejection unit and the media holding unit in the stacking direction, which is the direction in which the multiple ink layers overlap, the distance between the opposing surface and the ink ejection unit changes, thereby creating a stacking direction movement that moves relative to the medium in the stacking direction. By having the ink ejection unit perform this action, multiple layers of the ink are formed by stacking them. A printing method characterized in that, when the distance between the formed layer and the ejection head at the timing of starting to form a new layer of the ink on top of the already stacked layer of ink is defined as the layer-head distance, the moving drive unit causes the ink ejection unit to move in the stacking direction so that the layer-head distance becomes a distance within a preset range.

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