Image transfer sheet and image transfer method

Abstract

To provide an image transfer sheet that does not require special materials and easy to manufacture.SOLUTION: An image transfer sheet 10 includes: a release paper 20; a protective sheet 70 having an adhesive layer 71; an image layer 50 provided between the release paper 20 and the protective sheet 70 which is a layer of light-curable process color ink that has fully cured; an overcoat layer 60 being a light-curable transparent ink layer that has fully cured and is provided between the protective sheet 70 and the image layer 50 and attached to the adhesive layer 71 of the protective sheet 70; and an adhesive layer 30 provided between the release paper 20 and the image layer 50, which is a layer of light-curable ink that has partially cured and has adhesion to the transfer object. The adhesive layer 30 is of the same shape as the image layer 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image transfer sheet and an image transfer method. [Background technology]

[0002] Methods of printing an image on an image transfer sheet using a printer and transferring the image from the image transfer sheet to a transfer target have been known for some time. The configuration of image transfer sheets for this purpose is also known. For example, Patent Document 1 discloses an image transfer sheet in which an image layer is formed using a UV printer on release paper with a peelable adhesive layer, and a transfer film is superimposed on the image layer. The transfer film is releasable from the image layer and easily adheres to the adhesive layer. Therefore, according to Patent Document 1, when the adhesive layer of the image transfer sheet from which the release paper has been peeled is pressed against the transfer target and the transfer film is then peeled off, the image is transferred to the transfer target, and the adhesive layer outside the image is peeled off together with the transfer film. Patent Document 1 claims that this makes it possible to easily manufacture an image transfer sheet on which only the image can be transfer-printed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-209931 Summary of the Invention [Problem to be solved by the invention]

[0004] The image transfer sheet and image transfer method disclosed in Patent Document 1 require special printing media: release paper with a peelable adhesive layer formed thereon, and a transfer film that is peelable from the image layer and easily adheres to the adhesive layer. On the other hand, the typical conventional method of printing an image on printing media with a sticker attached to the release paper and then cutting around the image requires time for cutting the printing media, making it difficult to say that it is an easy method for producing an image transfer sheet.

[0005] The present invention has been made in view of the above points, and its object is to provide an image transfer sheet that does not require the use of special materials and is easy to manufacture, and also to provide a method for manufacturing such an image transfer sheet and transferring an image to a transfer target. [Means for solving the problem]

[0006] The image transfer sheet disclosed herein comprises a release paper, a protective sheet having an adhesive layer, an image layer which is a layer of fully cured photocurable process color ink and is provided between the release paper and the protective sheet, an overcoat layer which is a layer of fully cured photocurable clear ink and is provided between the protective sheet and the image layer and attached to the adhesive layer of the protective sheet, and an adhesive layer which is a layer of semi-cured photocurable ink that has adhesiveness to a transfer target and is provided between the release paper and the image layer. The adhesive layer has the same shape as the image layer.

[0007] The image transfer sheet functions as an image transfer sheet because the image of the image layer can be transferred to a transfer target by adhering the adhesive layer to the transfer target. Furthermore, the image transfer sheet can use a general-purpose release paper, eliminating the need for special materials. Furthermore, the image transfer sheet can be produced without cutting, making it easy to manufacture. Furthermore, the adhesive layer has the same shape as the image layer, allowing for a borderless transfer image.

[0008] The image transfer method disclosed herein includes the steps of: ejecting photocurable ink using an inkjet printer and irradiating the ink with light to semi-cure it, thereby forming an adhesive layer on a release paper that is adhesive to a transfer target; ejecting photocurable process color ink using an inkjet printer and irradiating the process color ink with light to completely cure it, thereby forming an image layer above the adhesive layer; ejecting photocurable transparent ink using an inkjet printer and irradiating the transparent ink with light to completely cure it, thereby forming an overcoat layer above the image layer; attaching an adhesive layer of a protective sheet to the overcoat layer; peeling the release paper from the adhesive layer; contacting the adhesive layer with the transfer target after the release paper has been peeled off; pressing the protective sheet toward the adhesive layer while the adhesive layer is in contact with the transfer target; and peeling the protective sheet from the overcoat layer. The adhesive layer has the same shape as the image layer.

[0009] According to the image transfer method, the image transfer sheet described above can be prepared and used to transfer an image onto an object to be transferred. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image transfer sheet according to a first embodiment. [Figure 2] 4 is a flowchart showing a procedure for producing an image transfer sheet according to the first embodiment. [Figure 3] 1 is a schematic diagram of a step of forming an adhesive layer. [Figure 4] 3A and 3B are schematic diagrams illustrating steps of forming a concealing layer. [Figure 5] 1 is a schematic diagram of a step of forming an image layer. [Figure 6] 3A to 3C are schematic diagrams illustrating steps of forming an overcoat layer. [Figure 7] 10 is a flowchart showing the procedure for image transfer using an image transfer sheet. [Figure 8] FIG. 2 is a schematic diagram of a step of peeling off the release paper. [Figure 9] FIG. 2 is a schematic diagram of a bonding step. [Figure 10] FIG. 10 is a schematic diagram of a step of peeling off an application sheet. [Figure 11] FIG. 10 is a schematic cross-sectional view of an image transfer sheet according to a second embodiment. [Figure 12] 10 is a flowchart showing a procedure for producing an image transfer sheet according to a second embodiment. [Figure 13] 3 is a schematic cross-sectional view of the image transfer sheet after image transfer onto the transfer target. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an image transfer sheet and an image transfer method according to several embodiments will be described with reference to the drawings. The embodiments described here are, of course, not intended to limit the present invention. Furthermore, the same reference numerals are used for components and parts that perform the same functions, and redundant descriptions will be omitted or simplified.

[0012] [First embodiment] [Image transfer sheet composition] Fig. 1 is a schematic cross-sectional view of an image transfer sheet 10 according to a first embodiment. The image transfer sheet 10 is a sheet that is adhered to a transfer target 5 (see Fig. 9) to transfer an image to the transfer target 5. As shown in Fig. 1, the image transfer sheet 10 includes a release paper 20, an adhesive layer 30 formed on the release paper 20, a concealing layer 40 formed on the adhesive layer 30, an image layer 50 formed on the concealing layer 40, an overcoat layer 60 formed on the image layer 50, and an application sheet 70 attached on the overcoat layer 60.

[0013] The release paper 20 is a substrate on which the adhesive layer 30 is formed. The release paper 20 is configured so that the adhesive layer 30 can be formed and the adhesive layer 30 can be easily peeled off. The release paper 20 is, for example, a paper sheet with a release treatment applied to its surface. The release treatment can be, for example, the formation of a silicone resin layer. However, the material of the release paper 20 and the method of surface treatment are not particularly limited. A general sticker backing or the like can be suitably used as the release paper 20. Although it is called "release paper," the material of the release paper 20 is not limited to paper and may be, for example, a resin sheet.

[0014] The adhesive layer 30 is an adhesive layer that is adhered to the release paper 20 when the image transfer sheet 10 is not adhered to the transfer target 5. When the image transfer sheet 10 is adhered to the transfer target 5, the adhesive layer 30 adheres to the transfer target 5. The adhesive layer 30 has adhesive properties to the transfer target 5. Here, "having adhesive strength" refers to, for example, a peel adhesion strength of 0.5 N / 10 mm or more at a peel angle of 180 degrees and a speed of 300 mm / min as specified in JIS Z 0237. However, the adhesive strength of the adhesive layer 30 is not limited to a level that can generally be said to "have adhesive strength." In this embodiment, the adhesive layer 30 is formed from a photocurable white ink. Specifically, the adhesive layer 30 is a layer of photocurable white ink semi-cured on the release paper 20. The photocurable ink here is a UV ink containing an ultraviolet-curable resin that cures when irradiated with ultraviolet light. However, there are no particular limitations on the components, properties, etc. of the photocurable ink. The adhesive layer 30 is formed on the release paper 20 by printing using an inkjet printer 100 (hereinafter referred to as printer 100, see FIG. 3). The printing process will be described later.

[0015] The adhesive layer 30 is formed to have the same shape as the image layer 50. This allows a borderless transfer image to be obtained, similar to a sticker with the periphery of the image cut out. The thickness of the adhesive layer 30 is not particularly limited.

[0016] The concealing layer 40 is an opaque layer formed by completely curing a photocurable white ink on the adhesive layer 30. The concealing layer 40 has a thickness that prevents the image layer 50 from being seen through. The concealing layer 40 is provided so that the image layer 50 develops a vivid color regardless of the color of the transfer object 5. The adhesive layer 30 is thin and may not provide sufficient concealment by itself, so the concealing layer 40 is provided here. Here, the thickness of the concealing layer 40 is thicker than that of the adhesive layer 30. However, the thickness of the concealing layer 40 is not particularly limited as long as the concealing layer 40 can be configured to be opaque. The concealing layer 40 is also formed by printing using the printer 100. The concealing layer 40 is also configured to have the same shape as the image layer 50.

[0017] The image layer 50 is a layer that constitutes an image to be transferred to the transfer target 5. The image layer 50 is formed on the concealing layer 40. The image layer 50 is a layer in which process color inks are completely cured on the concealing layer 40. Here, the process color inks are photocurable inks. The process color inks include, for example, CMYK (cyan, magenta, yellow, black) inks. However, the colors of the process color inks are not particularly limited. The image layer 50 is also formed by printing using the printer 100.

[0018] 1, the image layer 50 may be composed of a plurality of parts spaced apart from one another. The plurality of parts spaced apart from one another of the image layer 50 may each constitute an image to be transferred to a different object 5 or to a different location on the object 5. In other words, the image layer 50 may include a plurality of images to be transferred to different locations. The image layer 50 may also constitute a three-dimensional image having thickness.

[0019] The overcoat layer 60 is a layer for protecting the image layer 50, and is formed on the image layer 50. The overcoat layer 60 is a layer formed by completely curing a photo-curable transparent ink on the image layer 50. The overcoat layer 60 may be formed to have a glossy finish with a smooth and shiny surface, or may be formed to have a matte finish with an uneven surface that eliminates gloss. The overcoat layer 60 may also be formed with a three-dimensional pattern (texture pattern) to impart a design effect. The overcoat layer 60 is also formed by printing using the printer 100. The overcoat layer 60 is also configured to have the same shape as the image layer 50.

[0020] The application sheet 70 is a sheet attached to the overcoat layer 60. The application sheet 70 is an example of a protective sheet that protects the print layer consisting of the adhesive layer 30, the concealing layer 40, the image layer 50, and the overcoat layer 60. Here, the application sheet 70 is a transparent resin film with an adhesive layer 71 formed on one surface. However, the material and configuration of the application sheet 70 are not particularly limited as long as it can be attached to the overcoat layer 60. Here, the application sheet 70 is configured to have the same shape as the release paper 20. The application sheet 70 is attached to the release paper 20 on which the print layer is formed by the adhesive layer 71. A portion of the adhesive layer 71 of the application sheet 70 is attached to the overcoat layer 60, and another portion is attached to a portion of the release paper 20 on which the print layer is not formed. The application sheet 70 and the release paper 20 are components that are removed after the image transfer sheet 10 is transferred to the transfer target 5. The application sheet 70 and the release paper 20 are provided to improve the convenience of the image transfer sheet 10, such as storage, portability, and transfer operations.

[0021] [How to make an image transfer sheet] A method for producing the image transfer sheet 10 will be described below. FIG. 2 is a flowchart showing the procedure for producing the image transfer sheet 10 according to this embodiment. As shown in FIG. 2, in producing the image transfer sheet 10, first, in steps S01 and S02, an adhesive layer 30 that is adhesive to the transfer target 5 is formed on the release paper 20. In steps S01 and S02, photocurable white ink is ejected by the printer 100 and the white ink is semi-cured by being irradiated with light, thereby forming the adhesive layer 30 on the release paper 20. More specifically, in step S01, the photocurable white ink is ejected onto the release paper 20 by the printer 100. In step S02, the white ink ejected onto the release paper 20 is semi-cured by being irradiated with light, thereby forming the adhesive layer 30.

[0022] FIG. 3 is a schematic diagram showing steps S01 and S02 for forming the adhesive layer 30. As shown in FIG. 3, the printer 100 includes a flatbed 110, a carriage 120, a recording head 130 mounted on the carriage 120, and two light irradiation devices 141 and 142 also mounted on the carriage 120. The flatbed 110 is a support platform that supports an object to be printed. In this example, a release paper 20 is placed on the flatbed 110 as the object to be printed. The flatbed 110 is moved in the X direction (a direction perpendicular to the plane of the paper in FIG. 3) by a bed moving device (not shown). As the flatbed 110 moves in the X direction, the release paper 20 moves in the X direction. The carriage 120 is moved in the Y direction (a horizontal direction in FIG. 3) by a carriage moving device (not shown). As the carriage 120 moves in the Y direction, the recording head 130 and the light irradiation devices 141 and 142 mounted on the carriage 120 also move in the Y direction. Note that U and D in Figure 3 represent upward and downward, respectively. Y1 and Y2 in Figure 3 each represent one side of the Y direction. The X direction, Y direction, and up-down direction are perpendicular to each other. However, these directions are merely defined for the convenience of explanation and do not limit the installation mode of the printer 100 or the present invention in any way.

[0023] As shown in FIG. 3, the recording head 130 includes multiple ink heads 130W, 130G, 130C, 130M, 130Y, and 130K. The ink head 130W is configured to eject photo-curable white ink. The ink head 130G is configured to eject photo-curable clear ink. The ink heads 130M to 130K are configured to eject photo-curable process color inks. Specifically, the ink head 130C ejects photo-curable cyan ink. The ink head 130M ejects photo-curable magenta ink. The ink head 130Y ejects photo-curable yellow ink. The ink head 130K ejects photo-curable black ink. However, the process color inks are not limited to CMYK inks. As shown in FIG. 3, the multiple ink heads 130W to 130K are arranged side by side in the Y direction. Although not shown in the drawings, each of the ink heads 130W to 130K extends in the X direction.

[0024] The light irradiation devices 141 and 142 are each provided on a side surface of the carriage 120 in the Y direction. One of the light irradiation devices, 141, is positioned in the Y1 direction relative to the recording head 130. The other light irradiation device, 142, is positioned in the Y2 direction relative to the recording head 130. However, the light irradiation devices may be provided only in the Y1 direction or the Y2 direction relative to the recording head 130. The light irradiation devices 141 and 142 emit light that cures ink ejected from the recording head 130. The light irradiation devices 141 and 142 are equipped with multiple ultraviolet irradiation LEDs (not shown) and are configured to adjust the intensity of the emitted light by turning off some of the ultraviolet irradiation LEDs. However, the method by which the light irradiation devices 141 and 142 adjust the light intensity is not limited to the above. The light irradiation devices 141 and 142 may adjust the light intensity by, for example, adjusting the current flowing through the ultraviolet irradiation LEDs.

[0025] In the steps of forming the adhesive layer 30 (steps S01 and S02), the printer 100 ejects white ink from the ink head 130W toward the release paper 20 on the flatbed 110 while moving the carriage 120 in the Y1 direction. At this time, the light irradiation device 142 on the rear side of the carriage 120 in the movement direction irradiates light with an intensity that does not completely cure the white ink. The white ink that has landed on the release paper 20 is irradiated with light from the light irradiation device 142, thereby semi-curing the white ink. Note that because the white ink is exposed to light immediately after landing on the release paper 20, it is semi-cured with a grainy appearance remaining. In FIG. 2, step S02 is shown after step S01, but this is for convenience of illustration; as described above, steps S01 and S02 may be performed simultaneously.

[0026] The printer 100 repeats the above process while changing the relative position between the release paper 20 and the carriage 120 by moving the flatbed 110 in the X direction. This forms an adhesive layer 30 at a predetermined location on the release paper 20. However, if the adhesive layer 30 is small and there is no need to move the flatbed 110, the movement of the flatbed 110 may be omitted. The adhesive layer 30 may be formed from a single layer of white ink, or may be formed from multiple layers of white ink stacked vertically. Furthermore, the white ink of the adhesive layer 30 may not be semi-cured immediately after landing on the release paper 20, but may be allowed to level over time after landing before being semi-cured.

[0027] As shown in FIG. 2, in steps S03 and S04 following the steps of forming the adhesive layer 30 (steps S01 and S02), the printer 100 forms an opaque concealing layer 40 on the adhesive layer 30. In steps S03 and S04, the printer 100 ejects white ink and irradiates the white ink with light to completely cure it, thereby forming the opaque concealing layer 40 on the adhesive layer 30. More specifically, in step S03, the printer 100 ejects white ink onto the adhesive layer 30. In step S04, the white ink ejected onto the adhesive layer 30 is irradiated with light to completely cure the white ink, thereby forming the opaque concealing layer 40. FIG. 4 is a schematic diagram of the steps of forming the concealing layer 40 (steps S03 and S04). In steps S03 and S04, as in steps S01 and S02, the carriage 120 is moved in the Y1 direction while the ink head 130W ejects white ink toward the adhesive layer 30. At this time, the light irradiation device 141 on the front side in the movement direction of the carriage 120 emits light of an intensity sufficient to completely cure the white ink. When the carriage 120 returns in the Y2 direction, light from the light irradiation device 141 is irradiated onto the white ink that has landed on the adhesive layer 30. This completely cures the white ink. Since the white ink is exposed to light after some time has passed since it landed, it is leveled. This reduces the gaps between the white ink dots, improving the concealing ability of each white ink layer. However, because the thickness of each white ink layer becomes thinner due to leveling, the concealing layer 40 is formed by stacking multiple white ink layers.

[0028] However, the method for forming the concealing layer 40 is not limited as long as the desired concealing properties can be obtained. If possible, the concealing layer 40 may be formed from a single layer of white ink. Furthermore, the white ink of the concealing layer 40 may be cured immediately after landing on the adhesive layer 30.

[0029] In subsequent steps S05 and S06, an image layer 50 is formed on the adhesive layer 30 and the hiding layer 40. In steps S05 and S06, photocurable process color inks are ejected by the printer 100 and irradiated with light to completely cure the process color inks, thereby forming the image layer 50 on the hiding layer 40. More specifically, in step S05, the printer 100 ejects the process color inks onto the hiding layer 40. In step S06, the process color inks ejected onto the hiding layer 40 are completely cured to form the image layer 50. FIG. 5 is a schematic diagram of the steps of forming the image layer 50 (steps S05 and S06). Steps S05 and S06 are similar to steps S01 and S02, except that the ejected inks are process color inks, and the color image specified by the manufacturer of the image transfer sheet 10 is formed using the process color inks.

[0030] In subsequent steps S07 and S08, an overcoat layer 60 is formed on the image layer 50. In steps S07 and S08, the printer 100 ejects photocurable transparent ink and irradiates the transparent ink with light to completely cure it, thereby forming the overcoat layer 60 on the image layer 50. More specifically, in step S07, the printer 100 ejects transparent ink onto the image layer 50. In step S08, the transparent ink ejected onto the image layer 50 is completely cured to form the overcoat layer 60. FIG. 6 is a schematic diagram of the steps of forming the overcoat layer 60 (steps S07 and S08). Steps S07 and S08 are similar to steps S03 and S04, except that the ejected ink is transparent ink and the thickness of the overcoat layer 60 does not need to be as thick as the concealing layer 40. The transparent ink is leveled because it is exposed to light after some time has passed since it landed on the image layer 50. This smooths the surface of the overcoat layer 60, giving the overcoat layer 60 a glossy finish. As a result, the glossiness of the image transfer sheet 10 is improved. However, as described above, the overcoat layer 60 may be formed in a matte finish, or may have a textured pattern for a design effect. The thickness of the overcoat layer 60 is not particularly limited, and may be the same as or thicker than the concealing layer 40.

[0031] In step S09, an application sheet 70 is attached as a protective sheet onto the overcoat layer 60. An adhesive layer 71 of the application sheet 70 is attached to the overcoat layer 60. This completes the image transfer sheet 10. The transferred image of the image transfer sheet 10 thus formed is a color image specified by the manufacturer (however, if the specified image is a black and white image, the image is a black and white image). The image transfer sheet 10 is configured so that there is no border around the transferred image. However, it is also possible to create a border around the transferred image, for example, by using a concealing layer 40.

[0032] [Image transfer method] Next, the procedure for transferring an image using the image transfer sheet 10 will be described. Although not shown, if a single image transfer sheet 10 is formed with multiple transfer images to be transferred to multiple locations, the image transfer sheet 10 may be cut into multiple sections, each containing one transfer image, prior to transfer. FIG. 7 is a flowchart showing the procedure for transferring an image using the image transfer sheet 10. As shown in FIG. 7, when transferring an image using the image transfer sheet 10, first, in step S11, the top surface of the application sheet 70 is rubbed with a plate-shaped squeegee 200 (see FIG. 9). This ensures closer adhesion between the adhesive layer 30, the concealing layer 40, the image layer 50, and the overcoat layer 60. However, this procedure may also be performed during the production of the image transfer sheet 10 (after step S09). Furthermore, the tool for rubbing the top surface of the application sheet 70 is not limited to the plate-shaped squeegee 200; for example, the user's hand or a roller may be used. Step S11 may be omitted if not particularly necessary.

[0033] As shown in Fig. 7, in the subsequent step S12, the release paper 20 is peeled off from the adhesive layer 30. Fig. 8 is a schematic diagram of step S12. As shown in Fig. 8, in step S12, the release paper 20 is peeled off, but the application sheet 70 remains on the image transfer sheet 10 without being peeled off.

[0034] In step S13, the adhesive layer 30 from which the release paper 20 has been peeled is brought into contact with the transfer-receiving object 5. In the following step S14, the application sheet 70 is pressed toward the adhesive layer 30 while the adhesive layer 30 is in contact with the transfer-receiving object 5. FIG. 9 is a schematic diagram of step S14. As shown in FIG. 9, in step S14, for example, the upper surface of the application sheet 70 is rubbed with a squeegee 200 to press the application sheet 70 toward the adhesive layer 30. This causes the adhesive layer 30 to adhere to the transfer-receiving object 5 and to be bonded to the transfer-receiving object 5. In step S14, it is sufficient to bring the adhesive layer 30 into close contact with the transfer-receiving object 5. Therefore, in step S14, the application sheet 70 may be simply pressed toward the transfer-receiving object 5 without rubbing.

[0035] 7, in step S15 after step S14, the application sheet 70 is peeled off from the overcoat layer 60. Fig. 10 is a schematic diagram of step S15. This completes the transfer of the image printed on the image transfer sheet 10 to the transfer target 5.

[0036] [Effects of the first embodiment] As described above, the image transfer sheet 10 according to this embodiment includes a release paper 20, an application sheet 70 having an adhesive layer 71, and an image layer 50, which is a layer of fully cured photocurable process color ink and is disposed between the release paper 20 and the application sheet 70. The image transfer sheet 10 further includes an overcoat layer 60 disposed between the application sheet 70 and the image layer 50, and an adhesive layer 30 disposed between the release paper 20 and the image layer 50. The overcoat layer 60 is a layer of fully cured photocurable clear ink and is attached to the adhesive layer 71 of the application sheet 70. The adhesive layer 30 is a layer of semi-cured photocurable white ink and is adhesive to the transfer target 5. The production of this image transfer sheet 10 does not require a step of cutting the periphery of the image. Therefore, the image transfer sheet 10 according to this embodiment can be produced easily and quickly. Furthermore, this image transfer sheet 10 can be produced using a general-purpose release paper 20 and ink, rather than the special materials described in Patent Document 1.

[0037] Furthermore, the image transfer sheet 10 according to this embodiment includes an opaque concealing layer 40, which is a layer of fully cured white ink, disposed between the adhesive layer 30 and the image layer 50. This allows the image layer 50 formed on the concealing layer 40 to have a clear color regardless of the color of the transfer target 5. In this embodiment, the adhesive layer 30 is also formed of white ink. However, because a thick adhesive layer 30 could cause problems during the transfer process, the adhesive layer 30 is thinned and the concealing layer 40 is provided. Specifically, if the semi-cured adhesive layer 30 is thick, the adhesive layer 30 is more likely to protrude outside the image transfer sheet 10 when the image transfer sheet 10 is rubbed during the transfer process. Furthermore, if the semi-cured adhesive layer 30 is thick, the image layer 50 and the overcoat layer 60 are more likely to move and shift on the transfer target 5 when the image transfer sheet 10 is rubbed during the transfer process or when force is applied to the image transfer sheet 10 after the transfer process is completed. Therefore, in this embodiment, the adhesive layer 30 is thin, and the concealing layer 40 is thicker than the adhesive layer 30 .

[0038] In this embodiment, the ink forming the concealing layer 40 is white ink, but it may be another opaque special color ink. For example, if a metallic finish is desired for the image transfer sheet 10, the ink forming the concealing layer 40 may be metallic ink. In this embodiment, the adhesive layer 30 is also formed of white ink to further enhance the concealing properties, but the ink forming the adhesive layer 30 may be a special color ink other than white ink, such as a transparent ink. Furthermore, the process color ink forming the image layer 50 is not limited to photocurable ink. The process color ink forming the image layer 50 may be, for example, a thermosetting ink.

[0039] The image transfer sheet 10 according to this embodiment further includes an overcoat layer 60 in which a transparent ink is completely cured on the image layer 50. This configuration protects the image layer 50 with the overcoat layer 60, thereby improving the durability of the image transfer sheet 10. Furthermore, the image transfer sheet 10 according to this embodiment further includes an application sheet 70 attached to the overcoat layer 60. This configuration protects the image transfer sheet 10 before transfer, making it easy to store and carry. In this embodiment, as shown in step S14 of FIG. 7 , the adhesive layer 30 is brought into close contact with the transfer-receiving object 5 by rubbing the application sheet 70. Therefore, rubbing the application sheet 70 may scratch the application sheet 70. However, the application sheet 70 is peeled off in step S15 after step S14. Therefore, the image transfer sheet 10 can be adhered to the transfer-receiving object 5 without being scratched or soiled.

[0040] [Second embodiment] In the second embodiment, the image transfer sheet has a different adhesive layer and does not have a concealing layer. The other configurations of the image transfer sheet according to the second embodiment are the same as those of the first embodiment. In the following description of the second embodiment, components that perform the same functions as those of the first embodiment will be designated by the same reference numerals as those of the first embodiment, and duplicate descriptions will be omitted or simplified.

[0041] [Image transfer sheet composition] Fig. 11 is a schematic cross-sectional view of an image transfer sheet 11 according to the second embodiment. As shown in Fig. 11, the image transfer sheet 11 according to this embodiment includes a release paper 20, an adhesive layer 31 formed on the release paper 20, an image layer 50 formed on the adhesive layer 31, an overcoat layer 60 formed on the image layer 50, and an application sheet 70 attached on the overcoat layer 60.

[0042] The release paper 20 may be the same as or different from that in the first embodiment. The release paper 20 is preferably one that is readily available, such as a general sticker mount, but is not limited thereto. In this embodiment, the adhesive layer 31 is formed from a photocurable transparent ink. The adhesive layer 31 is a layer formed by semi-curing the photocurable transparent ink on the release paper 20, and has adhesive properties to the transfer target object 5. The adhesive layer 31 is a transparent layer. The adhesive layer 31 is formed on the release paper 20 by, for example, an inkjet printer 100 as shown in FIG. 3.

[0043] The adhesive layer 31 is also configured to have the same shape as the image layer 50. This allows a borderless transfer image to be obtained, as in the first embodiment. The thickness of the adhesive layer 31 may be approximately the same as the preferred thickness of the adhesive layer 30 according to the first embodiment. However, the thickness of the adhesive layer 31 is not particularly limited.

[0044] The image layer 50 is a layer in which process color inks are completely cured on the adhesive layer 31. The overcoat layer 60 is a layer in which transparent inks are completely cured on the image layer 50. The image layer 50 and the overcoat layer 60 are the same as those in the first embodiment. However, the image layer 50 is only required to be a layer in which process color inks are completely cured on the adhesive layer 31, and the inks used and their thicknesses are not particularly limited. The overcoat layer 60 is only required to be a layer in which transparent inks are completely cured on the image layer 50, and the inks used and their thicknesses are also not particularly limited. The application sheet 70 is also not particularly limited as long as it has an adhesive layer 71 and functions as a protective sheet.

[0045] [How to make an image transfer sheet] A method for producing an image transfer sheet 11 according to the second embodiment will be described below. FIG. 12 is a flowchart showing the steps for producing the image transfer sheet 11 according to the second embodiment. As shown in FIG. 12, in producing the image transfer sheet 11 according to this embodiment, first, in step S21, a photocurable transparent ink is ejected onto the release paper 20 by the printer 100. In the subsequent step S22, the transparent ink ejected onto the release paper 20 is irradiated with light to semi-cure the transparent ink, thereby forming an adhesive adhesive layer 31. The transparent ink of the adhesive layer 31 may be semi-cured immediately after landing on the release paper 20, or may be semi-cured after landing and leveling. The adhesive layer 31 may be formed from a single layer of transparent ink, or may be formed by laminating multiple layers of transparent ink.

[0046] In the following step S23, the printer 100 ejects process color ink onto the adhesive layer 31. In step S24, the process color ink ejected onto the adhesive layer 31 is completely cured, and the image layer 50 is formed.

[0047] In step S25, the printer 100 ejects transparent ink onto the image layer 50. In step S26, the transparent ink ejected onto the image layer 50 is completely cured to form the overcoat layer 60. The overcoat layer 60 may be formed in a glossy finish, or may be formed in a matte finish if necessary. The overcoat layer 60 may also have a texture pattern for a design effect. In step S27, an application sheet 70 is attached as a protective sheet onto the overcoat layer 60. The image transfer sheet 11 according to the second embodiment is thus completed.

[0048] The method of image transfer using the image transfer sheet 11 according to the second embodiment is the same as that of the first embodiment, and therefore will not be described further. Fig. 13 is a schematic cross-sectional view of the image transfer sheet 11 after image transfer to the transfer target 5 is completed. As shown in Fig. 13, after image transfer is completed, the adhesive layer 31 of the image transfer sheet 11 is adhered to the transfer target 5. An image layer 50 is formed on the adhesive layer 31, and an overcoat layer 60 is formed on the image layer 50. Finally, the release paper 20 and application sheet 70 are removed.

[0049] [Effects of the second embodiment] As described above, the image transfer sheet 11 according to this embodiment includes a release paper 20, an adhesive layer 31 formed by semi-curing a photocurable transparent ink on the release paper 20 and having adhesive properties, an image layer 50 formed by fully curing a process color ink on the adhesive layer 31, an overcoat layer 60 formed by fully curing a transparent ink on the image layer 50, and an application sheet 70 attached to the overcoat layer 60. Like the image transfer sheet 10 according to the first embodiment, this image transfer sheet 11 can be easily and quickly manufactured without using special materials. The image transfer sheet 11 according to this embodiment has a transparent adhesive layer 31, and the image layer 50 is formed on the transparent adhesive layer 31. The image transfer sheet 11 according to the second embodiment has fewer printed layers than the image transfer sheet 10 according to the first embodiment, and therefore can be manufactured even more easily and quickly than the image transfer sheet 10 according to the first embodiment. The image transfer sheet 11 according to this embodiment can be suitably used in cases where the influence of the color of the transfer target 5 is not particularly important or when the color of the transfer target 5 is desired to be visible through for a more natural finish. For example, when the transfer object 5 is white, the color development of the image transfer sheet 11 according to the second embodiment is generally the same as that of the image transfer sheet 10 according to the first embodiment.

[0050] The ink forming the adhesive layer 31 does not have to be a transparent photocurable ink, and may be, for example, an opaque photocurable ink. The ink forming the adhesive layer 31 may be, for example, a photocurable white ink.

[0051] [Other embodiments] Although several preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples, and the present invention can be embodied in various other forms.

[0052] For example, in the above-described embodiment, the image transfer sheet has an overcoat layer on the image layer and further has a protective sheet attached to the overcoat layer, but the image transfer sheet does not necessarily have to have an overcoat layer and a protective sheet. If the image transfer sheet has a protective sheet, the protective sheet may be attached directly to the image layer or via another layer. The layer interposed between the image layer and the protective sheet is not limited to an overcoat layer made of transparent ink, and may be, for example, an overcoat layer made of metallic ink or white ink that is partially formed on the image layer and provides a design effect.

[0053] In the above embodiment, the image transfer sheets 10 and 11 are produced by a flatbed printer 100 in which the flatbed 110 on which the printing object is placed moves, but they may also be produced by other types of printers, such as a roll-to-roll printer in which printing is performed while feeding a roll-shaped recording medium. In this case, the recording medium loaded into the roll-to-roll printer may be release paper wound in a roll.

[0054] Unless otherwise specified, the embodiments do not limit the present invention.

[0055] [Other inventions] The first image transfer sheet comprises a release paper, a protective sheet having an adhesive layer, an image layer which is a layer of fully cured photocurable process color ink and is provided between the release paper and the protective sheet, an overcoat layer which is a layer of fully cured photocurable transparent ink and is provided between the protective sheet and the image layer and is attached to the adhesive layer of the protective sheet, and an adhesive layer which is a layer of semi-cured photocurable ink and has adhesive properties to the object to be transferred and is provided between the release paper and the image layer.

[0056] The second image transfer sheet is the first image transfer sheet, the ink semi-cured on the adhesive layer is an opaque ink, The opaque ink is fully cured, and the opaque hiding layer is provided between the adhesive layer and the image layer.

[0057] The third image transfer sheet is the second image transfer sheet, The thickness of the hiding layer is greater than the thickness of the adhesive layer.

[0058] The fourth image transfer sheet is the first image transfer sheet, The ink that is semi-cured on the adhesive layer is a transparent ink.

[0059] The first image transfer method includes the steps of: ejecting photocurable ink using an inkjet printer and irradiating the ink with light to semi-cure it, thereby forming an adhesive layer on a release paper that is adhesive to the object to be transferred; ejecting photocurable process color ink using an inkjet printer and irradiating the process color ink with light to completely cure it, thereby forming an image layer above the adhesive layer; ejecting photocurable transparent ink using an inkjet printer and irradiating the transparent ink with light to completely cure it, thereby forming an overcoat layer above the image layer; adhering an adhesive layer of a protective sheet having an adhesive layer to the overcoat layer; peeling the release paper from the adhesive layer; contacting the adhesive layer after the release paper has been peeled off with the object to be transferred; pressing the protective sheet toward the adhesive layer while the adhesive layer is in contact with the object to be transferred; and peeling the protective sheet from the overcoat layer.

[0060] The second image transfer method is the first image transfer method, the ink semi-cured on the adhesive layer is an opaque ink, The method further includes, after the step of forming the adhesive layer and before the step of forming the image layer, a step of ejecting the opaque ink using an inkjet printer and irradiating the opaque ink with light to completely harden it, thereby forming an opaque hiding layer on the adhesive layer.

[0061] The third image transfer method is the first image transfer method, In this method, the ink that is semi-cured on the adhesive layer is a transparent ink. [Explanation of symbols]

[0062] 5. Transcription target 10 Image transfer sheet (first embodiment) 11 Image transfer sheet (second embodiment) 20 Release paper 30 adhesive layer (first embodiment) 31 adhesive layer (second embodiment) 40 Hidden Layer 50 image layers 60 Overcoat layer 70 Application Sheet (Protective Sheet) 100 Inkjet Printer

Claims

1. A release paper; A protective sheet having an adhesive layer; an image layer formed by completely curing a photocurable process color ink and disposed between the release paper and the protective sheet; an overcoat layer, which is a layer in which a photocurable transparent ink is completely cured, and which is provided between the protective sheet and the image layer and attached to the adhesive layer of the protective sheet; an adhesive layer, which is a layer of semi-cured photocurable ink and has adhesiveness to a transfer target, and is provided between the release paper and the image layer; the adhesive layer is conformal to the image layer; Image transfer sheet.

2. the overcoat layer is conformal to the image layer; The image transfer sheet according to claim 1 .

3. a step of ejecting a photocurable ink using an inkjet printer and semi-curing the ink by irradiating the ink with light, thereby forming an adhesive layer on a release paper that is adhesive to a transfer target; a step of ejecting photo-curable process color inks using an inkjet printer and irradiating the process color inks with light to completely cure them, thereby forming an image layer above the adhesive layer; a step of ejecting a photo-curable transparent ink using an inkjet printer and irradiating the transparent ink with light to completely cure the ink, thereby forming an overcoat layer on the image layer; a step of attaching an adhesive layer of a protective sheet having an adhesive layer to the overcoat layer; peeling the release paper from the adhesive layer; a step of contacting the adhesive layer after the release paper has been peeled off with an object to be transferred; pressing the protective sheet toward the adhesive layer while the adhesive layer is in contact with the transfer target; peeling the protective sheet from the overcoat layer; Including, the adhesive layer is conformal to the image layer; Image transfer method.

4. the overcoat layer is conformal to the image layer; The image transfer method according to claim 3 .

Images