Image formation apparatus and image formation method

Abstract

To provide an image formation apparatus capable of controlling the tactile sensation of printed matters.SOLUTION: An image formation apparatus includes: a first discharge part 10 for discharging a first ink containing curable resin; a second discharge part 20 for discharging a second ink containing curable resin whose hardness after curing is different from that of the first ink; and a control part 80 for controlling the first discharge part 10 and the second discharge part 20 so that the first ink and the second ink are discharged and cured, whereby multiple layers are laminated such that a three-dimensional printing image is formed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus that ejects ink containing a curable resin onto a print medium to form a three-dimensional printed image. [Background technology]

[0002] 2. Description of the Related Art Inkjet printing devices have been proposed that eject ink containing a curable resin onto a printing medium, and then repeatedly cure the ink using an energy irradiation device to form multiple resin layers, thereby forming a three-dimensional printed item.

[0003] By forming it in three dimensions in this way, highly design-oriented decoration is possible, and since it can even be colored using the inkjet method, highly expressive decoration is possible.

[0004] In such an inkjet printing apparatus, Patent Document 1 proposes a method of providing an adhesive primer layer between the printing medium and the UV ink coating.

[0005] Furthermore, Patent Documents 2 and 3 propose a method of changing the gloss of a printed material or controlling ink bleeding by controlling the time it takes for an ink containing a curable resin to harden after being ejected onto a printing medium. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-52378 A [Patent Document 2] JP 2010-5934 A [Patent Document 3] JP 2018-51791 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, an inkjet printing device that uses ink containing a curable resin can form printed matter into a three-dimensional shape, thereby producing printed matter with excellent design and expressiveness. Depending on the curable resin used, the hardness of the printed matter after curing is uniform, and the feel of the printed matter is also consistent.

[0008] Patent Documents 1 to 3 also make no proposal regarding a method for adjusting the feel of a printed matter.

[0009] SUMMARY OF THE PRESENT DISCLOSURE In view of the above circumstances, an object of the present invention is to provide an image forming apparatus capable of controlling the tactile feel of a printed matter. [Means for solving the problem]

[0010] The image forming apparatus of the present invention includes a first ejection section that ejects a first ink containing a curable resin, a second ejection section that ejects a second ink containing a curable resin having a different hardness after curing from the first ink, and a control section that controls the first ejection section and the second ejection section to eject and cure the first ink and the second ink, thereby stacking multiple layers to form a three-dimensional printed image. Effect of the Invention

[0011] According to the image forming device of the present invention, a first ink containing a curable resin and a second ink containing a curable resin having a different hardness after curing from the first ink are ejected onto a printing medium and cured, and multiple layers are stacked to form a three-dimensional printed image on the printing medium, thereby controlling the tactile feel of the printed material. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an inkjet printing apparatus using a first embodiment of an image forming apparatus of the present invention; [Diagram 2] FIG. 2 is a diagram showing how a three-dimensional printed image is formed by the inkjet printing device shown in FIG. 1; [Diagram 3] FIG. 2 is a block diagram showing the configuration of a control system of the inkjet printing apparatus shown in FIG. [Figure 4] FIG. 1 is a schematic diagram showing the configuration of an inkjet printing apparatus using a second embodiment of an image forming apparatus according to the present invention; [Diagram 5] FIG. 5 is a block diagram showing the configuration of a control system of the inkjet printing apparatus shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An inkjet printing apparatus using a first embodiment of the printing apparatus of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a schematic diagram of an inkjet printing apparatus 1 of this embodiment. In the following description of the embodiment, the up, down, left, right, front, and rear directions indicated by arrows in Fig. 1 are the up, down, left, right, front, and rear directions of the inkjet printing apparatus 1 of this embodiment.

[0014] As shown in FIG. 1, the inkjet printing apparatus 1 of this embodiment includes a first ejection section 10, a second ejection section 20, a UV irradiation section 30, and a print medium setting table 40.

[0015] The first ejection unit 10 ejects a first ink containing a curable resin. The first ejection unit 10 includes five inkjet heads 11-15. The five inkjet heads 11-15 eject first inks of different colors, for example, W (white), Y (yellow), M (magenta), C (cyan), and K (black). The first inks in this embodiment are inks containing a UV curable resin that is cured by irradiation with ultraviolet rays, and color materials of each color.

[0016] The second ejection section 20 ejects a second ink containing a curable resin, similar to the first ejection section 10, but the second ink has a higher hardness after curing than the first ink.

[0017] The second ejection section 20 includes five inkjet heads 21 to 25. The five inkjet heads 21 to 25 eject first inks of different colors, for example, eject second inks of W (white), Y (yellow), M (magenta), C (cyan) and K (black). The second inks of this embodiment are inks that contain a UV curable resin that is cured by irradiation with ultraviolet rays and color materials of each color, but as described above, the second inks are inks that have a different hardness after curing from the first inks.

[0018] The first discharge section 10 and the second discharge section 20 are integrally arranged side by side in the main scanning direction (left and right direction). The first discharge section 10 and the second discharge section 20 are supported by a first main scanning drive guide 50 so as to be movable in the main scanning direction (left and right direction). The first main scanning drive guide 50 moves the first discharge section 10 and the second discharge section 20 in the main scanning direction by a first main scanning drive motor 51 (see FIG. 3).

[0019] The UV irradiation unit 30 has a light source such as a lamp that emits ultraviolet (UV) rays, an LED (Light Emitting Diode) or an LD (Laser Diode), and irradiates ultraviolet rays onto the printing medium P onto which the above-mentioned first ink and second ink are ejected, thereby curing the first ink and second ink.

[0020] The UV irradiation unit 30 is supported movably in the main scanning direction (left and right direction) by a second main scanning drive guide 60. The second main scanning drive guide 60 moves the UV irradiation unit 30 in the main scanning direction by a second main scanning drive motor 61 (see FIG. 3).

[0021] The printing medium placement table 40 is a table on which the printing medium P is placed.

[0022] In this embodiment, a first ejection unit 10 and a second ejection unit 20 eject a first ink and a second ink onto a printing medium P placed on a printing medium setting stand 40 while moving in the main scanning direction, and a UV irradiation unit 30 moves in the main scanning direction and irradiates ultraviolet light onto the first ink and the second ink on the printing medium P, thereby forming a three-dimensional printed image.

[0023] FIG. 2 is a diagram showing how a three-dimensional printed image is formed by the inkjet printing device 1 of this embodiment. In this embodiment, the first discharge unit 10 and the second discharge unit 20 are moved multiple times in the main scanning direction to form a three-dimensional printed image. A single movement of the first discharge unit 10 and the second discharge unit 20 forms a layer image of one layer, and multiple movements of the first discharge unit 10 and the second discharge unit 20 form a layer image by stacking multiple layer images. In this embodiment, every time the first discharge unit 10 and the second discharge unit 20 move once in the main scanning direction, the UV irradiation unit 30 moves accordingly, and ultraviolet rays are irradiated for each layer to form a layer image. FIG. 2 shows how a fourth layer image L4 is formed on three layer layer images L1 to L3.

[0024] The inkjet printing apparatus 1 of this embodiment also includes a movement mechanism (not shown) that moves the first discharge unit 10, the second discharge unit 20, and the UV irradiation unit 30 in the sub-scanning direction (front-back direction). The movement mechanism includes an actuator such as a sub-scanning drive motor 70 (see FIG. 3) that moves the first discharge unit 10, the second discharge unit 20, and the UV irradiation unit 30 in the sub-scanning direction.

[0025] In the inkjet printing device 1 of this embodiment, the entire 3D printed image is formed by alternately repeating one or more movements of the first ejection section 10, the second ejection section 20 and the UV irradiation section 30 in the main scanning direction and movement in the sub-scanning direction.

[0026] The method of moving the first discharge unit 10, the second discharge unit 20 and the UV irradiation unit 30 may be such that the entire 3D printed image is formed layer by layer, or the units may be moved in the sub-scanning direction while forming the desired number of layers for each scanning section.

[0027] 3 is a block diagram showing a control system of the inkjet printing apparatus 1 of this embodiment. As shown in FIG. 3, the inkjet printing apparatus 1 of this embodiment includes a control unit 80 that controls the entire inkjet printing apparatus 1.

[0028] The control unit 80 controls the first main scanning drive motor 51, the second main scanning drive motor 61, and the sub-scanning drive motor 70, thereby controlling the movement of the first discharge unit 10, the second discharge unit 20, and the UV irradiation unit 30 in the main scanning direction and the sub-scanning direction.

[0029] The control unit 80 also includes a data receiving unit 81 , a data processing unit 82 , and a head control unit 83 .

[0030] The data receiving unit 81 receives 3D printing image data that is generated in a computer (not shown) and output from the computer. The 3D printing image data is made up of a plurality of pixel data that constitute a 3D printing image.

[0031] Each pixel data includes color information, hardness information, and height information. The color information is, for example, RGB data. The hardness information is information that indicates the hardness of each pixel after the 3D printed image is cured. The height information is information that indicates the number of layers that make up each pixel of the 3D printed image. In this embodiment, as described above, one layer is formed by one movement in the main scanning direction, so the height information is also the number of movements in the scanning direction.

[0032] The data processing unit 82 generates first ink drop data for controlling the ejection of a first ink from the first ejection unit 10 and second ink drop data for controlling the ejection of a second ink from the second ejection unit 20 based on the 3D printing image data received by the data receiving unit 81.

[0033] Specifically, the data processing unit 82 determines the total amount of ink per pixel per layer based on the density of each pixel data of the 3D print image data, and determines the ratios of K, C, M, Y, and W based on the color information of each pixel data of the 3D print image data. For example, the data processing unit 82 determines 10pl as the total amount of ink per pixel per layer, and determines K25%, C25%, and W50% as the ratios of K, C, M, Y, and W.

[0034] Then, the data processing unit 82 distributes the total amount of ink for one pixel between the first ink and the second ink in accordance with the hardness information of each pixel data.

[0035] Specifically, for example, when hardness information has four levels from 0 to 3, with larger values ​​of the hardness information meaning harder ink, if the hardness information is 0, the data processing unit 82 distributes all of the ink amounts of K25%, C25%, and W50% to the first ink. If the hardness information is 2, the ink amounts of K25% and C25% are distributed to the first ink, and the ink amount of W50% is distributed to the second ink. If the hardness information is 3, the ink amounts of K25%, C25%, and W50% are distributed to the second ink.

[0036] In this way, the first ink drop data and second ink drop data for printing one layer are generated by distributing the total amount of ink, 10 pl, per pixel in one layer between the first ink and the second ink.

[0037] When the number of layers of height information is three, the data processing unit 82 generates the first ink drop data and the second ink drop data for each layer by generating the first ink drop data and the second ink drop data for the first layer for three layers. In this case, the total amount of ink per pixel of the 3D printed image is 10pl x 3 layers = 30pl.

[0038] In the above explanation, a method for generating first ink drop data and second ink drop data for each layer has been described. However, it is not necessary to generate ink drop data for each layer. It is also possible to generate one sheet each of first ink drop data indicating the amount of first ink in each pixel and second ink drop data indicating the amount of second ink, and have each pixel retain height information.

[0039] The head control unit 83 controls the inkjet heads 11-15 of the first ejection unit 10 to eject the first ink of each color based on the first ink drop data of each color for each layer generated by the data processing unit 82, and controls the inkjet heads 21-25 of the second ejection unit 20 to eject the second ink of each color based on the second ink drop data.

[0040] The control unit 80 includes a CPU (Central Processing Unit) and a storage medium such as a semiconductor memory, and controls each unit by executing a program pre-stored in the storage medium and operating electric circuits.

[0041] In this embodiment, the first ink drop data and the second ink drop data are generated by the data processing unit 82 of the control unit 80 of the inkjet printing device 1, but this data processing may also be performed within the computer that outputs the above-mentioned 3D printing image data, and the first ink drop data and the second ink drop data may be output from the computer to the inkjet printing device 1.

[0042] Next, an inkjet printing apparatus 2 using a second embodiment of the printing apparatus of the present invention will be described. Fig. 4 is a schematic diagram of the inkjet printing apparatus 2 of this embodiment. In the following description of the embodiment, the up, down, left, right, front, and rear directions indicated by arrows in Fig. 4 are the up, down, left, right, front, and rear directions of the inkjet printing apparatus 2 of this embodiment. The following description will focus on the configuration that differs from the inkjet printing apparatus 1 of the first embodiment.

[0043] As shown in FIG. 4, the inkjet printing apparatus 2 of this embodiment includes a first discharge unit 90, a second discharge unit 91, a third discharge unit 92, a UV irradiation unit 30, and a print medium setting table 40.

[0044] The first ejection unit 90 ejects a first ink containing a UV curable resin that is cured by irradiation with ultraviolet rays, but unlike the first embodiment, the first ejection unit 90 ejects the first ink that does not contain a coloring material. The first ejection unit 90 includes one inkjet head that ejects the above-mentioned first ink.

[0045] The second ejection unit 91 ejects a second ink that does not contain a coloring material and contains a UV curable resin that is cured by irradiation with ultraviolet rays, similar to the first ejection unit 90. The second ink has a higher hardness after curing than the first ink. The second ejection unit 91 includes one inkjet head that ejects the above-mentioned second ink.

[0046] The third ejection unit 92 ejects color ink that does not contain a curable resin but contains a color material. The third ejection unit 92 includes five inkjet heads 93-97. The five inkjet heads 93-97 eject color ink of different colors, for example, W (white), Y (yellow), M (magenta), C (cyan), and K (black).

[0047] In other words, the inkjet printing device 2 of the second embodiment uses a first ink and a second ink containing a UV-curable resin that does not contain a coloring material to form a three-dimensional layer of UV-curable resin, and uses color inks for coloring, thereby making it possible to reduce the number of inkjet heads used.

[0048] The first discharge section 90, the second discharge section 91, and the third discharge section 92 are arranged side by side in the main scanning direction (left and right direction) and are integrally disposed. The first discharge section 90, the second discharge section 91, and the third discharge section 92 are supported by a first main scanning drive guide 50 so as to be movable in the main scanning direction (left and right direction). The first main scanning drive guide 50 moves the first discharge section 90, the second discharge section 91, and the third discharge section 92 in the main scanning direction by a first main scanning drive motor 51.

[0049] The UV irradiation section 30, the second main scanning drive guide 60, the second main scanning drive motor 61, and the print medium setting table 40 are similar to those of the inkjet printing apparatus 1 of the first embodiment.

[0050] In this embodiment, the third ejection unit 92 moves in the main scanning direction onto the printing medium P placed on the printing medium setting table 40, ejecting C, M, Y, K, and W color inks to print a two-dimensional print image on the printing medium P. Then, the first ejection unit 90 and the second ejection unit 91 move in the main scanning direction to eject the first ink and the second ink onto the two-dimensional print image, and the UV irradiation unit 30 moves in the main scanning direction to irradiate the first ink and the second ink with ultraviolet light, thereby forming a layer of UV-curable resin.

[0051] In this embodiment, the first discharge unit 90, the second discharge unit 91, and the third discharge unit 92 are also moved multiple times in the main scanning direction to form a three-dimensional printed image. For example, during one movement of the first discharge unit 90, the second discharge unit 91, and the third discharge unit 92, color ink is discharged from the third discharge unit 92 to print a two-dimensional print image, and during the second and subsequent movements, the first and second inks are discharged from the first discharge unit 90 and the second discharge unit 91 to form a layer of UV-curable resin. Then, multiple layers of UV-curable resin are stacked by multiple movements from the second time onwards to form a three-dimensional printed image.

[0052] In this embodiment, too, each time the first ejection section 90, the second ejection section 91, and the third ejection section 92 move, the UV irradiation section 30 moves accordingly, and when the first ink and the second ink are ejected, ultraviolet light is irradiated to form a layer of UV-curable resin.

[0053] The inkjet printing apparatus 2 of this embodiment also includes a movement mechanism (not shown) that moves the first discharge unit 90, the second discharge unit 91, the third discharge unit 92 and the UV irradiation unit 30 in the sub-scanning direction (front-back direction).

[0054] In the inkjet printing device 2 of this embodiment, the entire three-dimensional printed image is formed by alternately repeating one or more movements of the first ejection section 90, the second ejection section 91, the third ejection section 92 and the UV irradiation section 30 in the main scanning direction and movement in the sub-scanning direction.

[0055] The first discharge unit 90, the second discharge unit 91, the third discharge unit 92 and the UV irradiation unit 30 may be moved in such a way that the entire 3D printed image is formed layer by layer, or the desired number of layers may be formed for each scanning section by moving them in the sub-scanning direction.

[0056] Fig. 5 is a block diagram showing the configuration of a control system of the inkjet printing apparatus 2 of this embodiment. The control system of the inkjet printing apparatus 2 of this embodiment has the same configuration as that of the inkjet printing apparatus 1 of the first embodiment shown in Fig. 3, except that a third ejection unit 92 is added.

[0057] The data processing unit 82 of this embodiment generates first ink drop data for controlling the ejection of a first ink from the first ejection unit 90, second ink drop data for controlling the ejection of a second ink from the second ejection unit 91, and third ink drop data for controlling the ejection of a color ink from the third ejection unit 92 based on the 3D printing image data received by the data receiving unit 81.

[0058] The data processing unit 82 generates the third ink drop data based on the color information of each pixel data constituting the 3D print image data received by the data receiving unit 81.

[0059] Then, the data processing unit 82 generates the first ink drop data and the second ink drop data for each layer based on the hardness information and the height information of each pixel data. Note that the first ink amount and the second ink amount may be calculated based on the ink amount, hardness information, and the number of layers of the height information of each pixel of the third ink drop data, or may be calculated based on the ink amount, hardness information, and the number of layers of the height information that are preset.

[0060] In the above explanation, a method for generating first ink drop data and second ink drop data for each layer has been described. However, it is not necessary to generate ink drop data for each layer. It is also possible to generate one sheet each of first ink drop data indicating the amount of first ink in each pixel and second ink drop data indicating the amount of second ink, and have each pixel retain height information.

[0061] The head control unit 83 controls the inkjet heads 93-97 of the third ejection unit 92 to eject ink of each color based on the third ink drop data generated by the data processing unit 82. In addition, the head control unit 83 controls the inkjet head of the first ejection unit 90 to eject the first ink based on the first ink drop data for each layer, and controls the inkjet head of the second ejection unit 91 to eject the second ink based on the second ink drop data.

[0062] In the inkjet printing apparatuses 1 and 2 of the first and second embodiments, a UV-curable resin is used as the curable resin, but the present invention is not limited to this, and other active energy ray-curable resins such as electron beam-curable resins or thermosetting resins may be used. In addition, the hardness of these curable resins may be adjusted by changing the content of the polymerizable compound, or curable resins with different degrees of polymerization may be used.

[0063] In the inkjet printing apparatuses 1 and 2 of the first and second embodiments, the ratio of the first ink to the second ink is determined based on the hardness information of each pixel, but the first layer may be made lower in hardness than the second and subsequent layers to improve adhesion to the printing medium. Also, a process may be added to improve abrasion resistance by forming the top layer of each pixel with the ink having a higher hardness.

[0064] Furthermore, in the inkjet printing apparatus 1 of the first embodiment described above, an inkjet head may be further provided that ejects ink containing a UV-curable resin that does not contain coloring material, and the ink may be selectively used to form the top layer, thereby enabling a process that can selectively impart gloss.

[0065] In the inkjet printing apparatuses 1 and 2 of the first and second embodiments, the hardness of each pixel is adjusted by adjusting the ratio of the amount of the first ink to the amount of the second ink for each pixel, but the method of adjusting the hardness of a 3D printed image is not limited to such adjustment in units of one pixel, and may be adjusted, for example, in units of multiple pixels. Specifically, the hardness may be adjusted by adjusting the ratio of pixels printed with the first ink to pixels printed with the second ink among 9 pixels of 3×3. The multiple pixel units are not limited to 3×3, and may be 2×2 or 4×4 or larger.

[0066] According to the inkjet printing apparatuses 1 and 2 of the first and second embodiments, a first ink containing a UV-curable resin and a second ink containing a UV-curable resin having a hardness after curing different from that of the first ink are ejected onto the printing medium P and cured, and a plurality of layers are laminated to form a three-dimensional printed image on the printing medium P, so that the tactile feel of the printed matter can be controlled. In this embodiment, the tactile feel of the printed matter can be sensed not only in terms of hardness and softness, but also in terms of unevenness, roughness, smoothness, etc.

[0067] Furthermore, in the inkjet printing devices 1 and 2 of the first and second embodiments described above, the 3D printing image data includes color information and hardness information for each pixel, so that the hardness of each pixel of the 3D printing image can be set arbitrarily, thereby increasing the freedom of expression.

[0068] In addition, since the amount of the first ink and the amount of the second ink are determined based on the hardness information for each pixel, the amount of the first ink and the amount of the second ink can be determined by simple calculation processing.

[0069] Furthermore, since the 3D print image data contains height information for each pixel and the number of layers is determined based on the height information, the number of layers can be easily determined.

[0070] Furthermore, since the number of movements in the main scanning direction is controlled based on the height information, the number of layers can be easily controlled.

[0071] Furthermore, the present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, all the components shown in the embodiment may be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention.

[0072] The present invention further discloses the following supplementary notes.

[0073] (Appendix 1) The image forming apparatus of the present invention includes a first ejection section that ejects a first ink containing a curable resin, a second ejection section that ejects a second ink containing a curable resin having a different hardness after curing from the first ink, and a control section that controls the first ejection section and the second ejection section to eject and cure the first ink and the second ink, thereby stacking multiple layers to form a three-dimensional printed image.

[0074] (Appendix 2) In the image forming device described in Appendix 1, the control unit receives 3D printing image information and forms a 3D printed image based on the received 3D printing image information, and the 3D printing image information can include color information and hardness information for each pixel that constitutes the 3D printed image.

[0075] (Appendix 3) In the image forming apparatus described in Supplementary Note 2, the control unit can determine the amount of the first ink and the amount of the second ink based on the hardness information for each pixel.

[0076] (Appendix 4) In the image forming apparatus according to Supplementary Note 2 or Supplementary Note 3, the 3D print image information can include height information for each pixel, and the control unit can determine the number of layers based on the height information.

[0077] (Appendix 5) In the image forming device described in Appendix 4, the control unit forms a three-dimensional printed image by moving the first and second ejection units relative to the printing medium in the main scanning direction, and can control the number of movements in the main scanning direction based on height information.

[0078] (Appendix 6) The image forming method of the present invention ejects a first ink containing a curable resin and a second ink containing a curable resin having a different hardness after curing from the first ink onto a printing medium, cures them, and stacks multiple layers to form a three-dimensional printed image on the printing medium. [Explanation of symbols]

[0079] 1,2 Inkjet printing device 11~15 Inkjet head 21~25 Inkjet head 30 UV irradiation section 40 Print media installation stand 70 Sub-scanning drive motor 80 Control section 81 Data receiving unit 82 Data Processing Unit 83 Head control unit 93~97 Inkjet head L1~L4 layer images P Print media

Claims

1. a first ejection unit that ejects a first ink containing a curable resin; a second ejection unit that ejects a second ink containing a hardening resin having a hardness after hardening different from that of the first ink; and a control unit that controls the first ejection unit and the second ejection unit to eject and harden the first ink and the second ink to stack multiple layers to form a three-dimensional printed image.

2. The control unit receives 3D print image information, and forms the 3D print image based on the received 3D print image information.

2. The image forming apparatus according to claim 1, wherein the 3D print image information includes color information and hardness information for each pixel constituting the 3D print image.

3. 3. The image forming apparatus according to claim 2, wherein the control unit determines the amount of the first ink and the amount of the second ink based on the hardness information for each pixel.

4. The 3D printing image information includes height information for each pixel, The image forming apparatus according to claim 2 , wherein the control unit determines the number of layers based on the height information.

5. 5. The image forming apparatus according to claim 4, wherein the control unit forms the three-dimensional printed image by moving the first ejection unit and the second ejection unit relative to the printing medium in a main scanning direction, and controls the number of movements in the main scanning direction based on the height information.

6. An image forming method in which a first ink containing a curable resin and a second ink containing a curable resin having a different hardness after curing from the first ink are ejected onto a printing medium and cured, and multiple layers are laminated to form a three-dimensional printed image on the printing medium.

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