Image transfer sheet and image transfer method

Abstract

To provide an image transfer sheet that does not require the use of special materials and that can be manufactured easily.SOLUTION: An image transfer sheet 10 includes a release paper 20, a protective sheet 70 having an adhesive layer 71, an image layer 50 that is a layer in which photocurable process color ink is completely cured and that is provided between the release paper 20 and the protective sheet 70, an overcoat layer 60 that is a layer in which photocurable transparent ink is completely cured and that is provided between the protective sheet 70 and an image layer 50, and is adhered to an adhesive layer 71 of the protective sheet 70, and an adhesive layer 30 that is a layer in which photocurable ink is semi-cured, that has adhesiveness to the material to be transferred, and that is provided between the release paper 20 and 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 Art

[0002] A method of printing an image on an image transfer sheet by a printer and transferring the image of the image transfer sheet to an object to be transferred has been conventionally known. Also, the configuration of an image transfer sheet for that purpose is known. For example, Patent Document 1 discloses an image transfer sheet in which an image layer is formed on a release paper having a peelable adhesive layer by a UV printer, and a transfer film is overlaid on the image layer. The transfer film has peelability with respect to the image layer and easy adhesiveness with respect to the adhesive layer. Therefore, according to Patent Document 1, when the transfer film is peeled off after pressing the adhesive layer of the image transfer sheet from which the release paper has been peeled onto the transfer target, the image is transferred to the transfer target, and the adhesive layer outside the image is peeled off together with the transfer film. According to Patent Document 1, it is said that an image transfer sheet capable of transferring and printing only an image can be easily manufactured in this way.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The image transfer sheet and the image transfer method disclosed in Patent Document 1 require a special printing medium such as a release paper having a peelable adhesive layer and a transfer film having peelability with respect to the image layer and easy adhesiveness with respect to the adhesive layer. On the other hand, a conventional typical method of printing an image on a printing medium with a seal attached to the release paper and cutting around the image requires time for cutting the printing medium, so it is hard to say that it is an easy method for manufacturing an image transfer sheet.

[0005] The present invention has been made in view of such a point, and an object thereof is to provide an image transfer sheet that does not require the use of special materials and is easy to manufacture. Another object is to provide a method for producing such an image transfer sheet and transferring an image to a transfer object.

Means for Solving the Problems

[0006] The image transfer sheet disclosed herein includes a release paper, a protective sheet having an adhesive layer, a layer in which a photocurable process color ink is completely cured, and an image layer provided between the release paper and the protective sheet, a layer in which a photocurable transparent ink is completely cured, an overcoat layer provided between the protective sheet and the image layer and adhered to the adhesive layer of the protective sheet, and an adhesive layer in which a photocurable ink is semi-cured, having adhesiveness to a transfer object and provided between the release paper and the image layer.

[0007] Since the above image transfer sheet can transfer the image of the image layer to the transfer object by adhering the adhesive layer to the transfer object, it functions as an image transfer sheet. And according to the above image transfer sheet, a general-purpose release paper can be used, so that special materials do not have to be used. Furthermore, since the above image transfer sheet can be manufactured without cutting, it is easy to manufacture.

[0008] Further, the image transfer method disclosed herein includes steps of ejecting a photocurable ink by an inkjet printer, irradiating the ink with light to semi-cure it, and forming an adhesive layer having adhesiveness to a transfer target on a release paper; ejecting a photocurable process color ink by an inkjet printer, irradiating the process color ink with light to fully cure it, and forming an image layer above the adhesive layer; ejecting a photocurable transparent ink by an inkjet printer, irradiating the transparent ink with light to fully cure it, and forming an overcoat layer above the image layer; attaching the adhesive layer of a protective sheet having an adhesive layer to the overcoat layer; peeling the release paper from the adhesive layer; bringing the adhesive layer after the release paper is peeled into contact with the transfer target; pressing the protective sheet toward the adhesive layer with the adhesive layer in contact with the transfer target; and peeling the protective sheet from the overcoat layer.

[0009] According to the above image transfer method, the above-described image transfer sheet can be produced and used to transfer an image to a transfer target.

Brief Description of Drawings

[0010]

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[0011] Hereinafter, with reference to the drawings, an image transfer sheet and an image transfer method according to some embodiments will be described. The embodiments described here are not, of course, intended to particularly limit the present invention. Also, members and parts having the same function are denoted by the same reference numerals, and overlapping explanations are omitted or simplified.

[0012] [First Embodiment] [Configuration of Image Transfer Sheet] FIG. 1 is a schematic cross-sectional view of an image transfer sheet 10 according to the first embodiment. The image transfer sheet 10 is a sheet for transferring an image to an object to be transferred 5 (see FIG. 9) by being adhered to the object to be transferred 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 concealment layer 40 formed on the adhesive layer 30, an image layer 50 formed on the concealment 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 base material on which the adhesive layer 30 is formed. The release paper 20 is configured to be able to form the adhesive layer 30 and to be easily peelable from the adhesive layer 30. The release paper 20 is, for example, a paper sheet having a release treatment on its surface. As the release treatment, for example, formation of a silicone resin layer is performed. However, the material of the release paper 20 and the method of surface treatment are not particularly limited. As the release paper 20, general seal base paper or the like can be preferably used. Note that 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 or the like.

[0014] The adhesive layer 30 is a layer having adhesiveness, and is adhered to the release paper 20 in a state where the image transfer sheet 10 is not adhered to the object to be transferred 5. When the image transfer sheet 10 is adhered to the object to be transferred 5, the adhesive layer 30 is adhered to the object to be transferred 5. The adhesive layer 30 has adhesiveness to the object to be transferred 5. Here, "having adhesive force" means, for example, that the peel adhesion force at a peel angle of 180 degrees and a speed of 300 mm / min as defined in JIS Z 0237 is 0.5 N / 10 mm or more. However, the adhesive force of the adhesive layer 30 is not limited as long as it is generally an adhesive force equal to or greater than the level that can be said to "have adhesive force". In the present embodiment, the adhesive layer 30 is formed of a photocurable white ink. Specifically, the adhesive layer 30 is a layer in which the photocurable white ink is semi-cured on the release paper 20. The photocurable ink is, here, a UV ink containing an ultraviolet curable resin that is cured by irradiating ultraviolet rays. However, the components, characteristics, etc. of the photocurable ink are not particularly limited. The adhesive layer 30 is formed on the release paper 20 by printing with 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 configured to have the same shape as the image layer 50. Thereby, a transfer image without an edge can be obtained in the same manner as a seal obtained by cutting around the image. The thickness of the adhesive layer 30 is not particularly limited.

[0016] The hidden layer 40 is a layer in which the photocurable white ink is completely cured on the adhesive layer 30 and is configured to be opaque. The hidden layer 40 has a thickness such that the underlying layer cannot be seen through. The hidden layer 40 is a layer provided so that the image layer 50 can clearly develop color regardless of the color of the transfer object 5. The adhesive layer 30 is thin and may not provide sufficient hiding power on its own, so the hidden layer 40 is provided. Here, the thickness of the hidden layer 40 is greater than that of the adhesive layer 30. However, as long as the hidden layer 40 can be configured to be opaque, the thickness of the hidden layer 40 is not particularly limited. The hidden layer 40 is also formed by printing with the printer 100. The hidden 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 the image to be transferred to the transfer object 5. The image layer 50 is formed on the hidden layer 40. The image layer 50 is a layer in which the process color ink is completely cured on the hidden layer 40. The process color ink is, here, a photocurable ink. The process color ink includes, for example, CMYK (cyan, magenta, yellow, black) ink. However, the color of the process color ink is not particularly limited. The image layer 50 is also formed by printing with the printer 100.

[0018] As shown in FIG. 1, the image layer 50 may be composed of a plurality of separated parts. The plurality of separated parts of the image layer 50 may each constitute an image to be transferred to a different transfer object 5 or a different location of the transfer object 5. That is, the image layer 50 may include a plurality of images with different transfer locations. Also, the image layer 50 may constitute a three-dimensional image having a 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 in which a photocurable transparent ink is completely cured on the image layer 50. The overcoat layer 60 may be formed in a glossy finish with a smooth and shiny surface, or may be formed in a matte finish with unevenness on the surface and loss of gloss. Further, a three-dimensional pattern (texture pattern) for imparting a design effect may be formed on the overcoat layer 60. The overcoat layer 60 is also formed by printing by the printer 100. The overcoat layer 60 is also configured in the same shape as the image layer 50.

[0020] The application sheet 70 is a sheet pasted on the overcoat layer 60. The application sheet 70 is an example of a protective sheet for protecting the printing layer composed 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 having 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 pasted on the overcoat layer 60. Here, the application sheet 70 is configured in the same shape as the release paper 20. The application sheet 70 is pasted on the release paper 20 on which the printing layer is formed by the adhesive layer 71. A part of the adhesive layer 71 of the application sheet 70 is pasted on the overcoat layer 60, and the other part is pasted on the part of the release paper 20 where the printing layer is not formed. The application sheet 70 and the release paper 20 are members to be removed after the image transfer sheet 10 is transferred to the object to be transferred 5. The application sheet 70 and the release paper 20 are provided to improve the convenience of storage, transportation, and transfer work of the image transfer sheet 10.

[0021] [Method for producing an image transfer sheet] The method for manufacturing the image transfer sheet 10 will be described below. FIG. 2 is a flowchart showing the manufacturing procedure of the image transfer sheet 10 according to the present embodiment. As shown in FIG. 2, in manufacturing the image transfer sheet 10, first, in steps S01 and S02, an adhesive layer 30 having adhesiveness to the object to be transferred 5 is formed on the release paper 20. In steps S01 and S02, a photocurable white ink is ejected by the printer 100 and irradiated with light to be semi-cured, thereby forming the adhesive layer 30 on the release paper 20. Specifically, in step S01, the photocurable white ink is ejected by the printer 100 onto the release paper 20. In step S02, the white ink ejected onto the release paper 20 is irradiated with light to be semi-cured, thereby forming the adhesive layer 30 having adhesiveness.

[0022] FIG. 3 is a schematic diagram showing the steps (steps S01 and S02) of forming the adhesive layer 30. As shown in FIG. 3, the printer 100 includes a flat bed 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 flat bed 110 is a support base for supporting the object to be printed. Here, the release paper 20 is placed on the flat bed 110 as the object to be printed. The flat bed 110 is moved in the X direction (the direction perpendicular to the plane of FIG. 3) by a bed moving device (not shown). When the flat bed 110 moves in the X direction, the release paper 20 moves in the X direction. The carriage 120 is moved in the Y direction (the left-right direction in FIG. 3) by a carriage moving device (not shown). When 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. In FIG. 3, U and D represent upward and downward, respectively. Y1 and Y2 in FIG. 3 each represent one direction in the Y direction. The X direction, the Y direction, and the vertical direction are orthogonal to each other. However, these directions are merely directions defined for convenience of explanation and do not limit the installation mode of the printer 100 in any way, nor do they limit the present invention in any way.

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

[0024] The light irradiation devices 141 and 142 are respectively provided on the side surfaces in the Y direction of the carriage 120. One of the light irradiation devices 141 is arranged in the Y1 direction with respect to the recording head 130. The other light irradiation device 142 is arranged in the Y2 direction with respect to the recording head 130. However, the light irradiation devices may be provided only in the Y1 direction or the Y2 direction with respect to the recording head 130. The light irradiation devices 141 and 142 irradiate light for curing the ink ejected from the recording head 130. The light irradiation devices 141 and 142 are here provided with a plurality of ultraviolet irradiation LEDs (not shown) and are configured such that the intensity of the irradiated light can be adjusted 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, for example, by 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 discharges white ink from the ink head 130W toward the release paper 20 on the flat bed 110 while moving the carriage 120 in the Y1 direction. At this time, the light irradiation device 142 on the rear side in the moving direction of the carriage 120 irradiates light with an intensity such that the white ink is not completely cured. The white ink that lands on the release paper 20 is irradiated with light from the light irradiation device 142. Thereby, the white ink is semi-cured. Since the white ink receives light immediately after landing on the release paper 20, it is semi-cured while a granular feeling remains. In FIG. 2, step S02 is illustrated after step S01, but this is for convenience of illustration, and steps S01 and S02 may be performed simultaneously as described above.

[0026] The printer 100 repeats the above while changing the relative position between the release paper 20 and the carriage 120 by moving the flat bed 110 in the X direction. Thereby, the adhesive layer 30 is formed at a predetermined location on the release paper 20. However, when the adhesive layer 30 is small and it is not necessary to move the flat bed 110, the movement of the flat bed 110 may be omitted. The adhesive layer 30 may be formed by a single layer of white ink or may be formed by a plurality of layers of white ink overlapping in the vertical direction. Further, the white ink of the adhesive layer 30 may not be semi-cured immediately after landing on the release paper 20, but may be semi-cured after leveling (hereinafter also referred to as leveling) after a lapse of time after landing.

[0027] As shown in FIG. 2, in steps S03 and S04 after the steps (steps S01 and S02) of forming the adhesive layer 30, an opaque shielding layer 40 is formed on the adhesive layer 30 by the printer 100. In steps S03 and S04, the printer 100 discharges white ink and irradiates the white ink with light to fully cure it, thereby forming an opaque shielding layer 40 on the adhesive layer 30. Specifically, in step S03, the printer 100 discharges white ink onto the adhesive layer 30. In step S04, the white ink discharged onto the adhesive layer 30 is irradiated with light to fully cure the white ink, thereby forming an opaque shielding layer 40. FIG. 4 is a schematic diagram of the steps (steps S03 and S04) of forming the shielding layer 40. In steps S03 and S04, similar to steps S01 and S02, while moving the carriage 120 in the Y1 direction, white ink is discharged from the ink head 130W toward the adhesive layer 30. The light irradiation device 141 on the front side in the moving direction of the carriage 120 irradiates light with an intensity that fully cures the white ink at this time. The white ink that has landed on the adhesive layer 30 is irradiated with light from the light irradiation device 141 when the carriage 120 returns in the Y2 direction. As a result, the white ink is fully cured. Since the white ink receives light after a certain time has passed after landing, it is leveled. As a result, the gaps between the ink dots of the white ink are reduced, and the shielding property per layer of the white ink is improved. However, since the thickness of one layer of white ink becomes thinner due to leveling, the shielding layer 40 is formed by laminating a plurality of white ink layers.

[0028] However, as long as the desired shielding property is obtained, the method of forming the shielding layer 40 is not limited. If possible, the shielding layer 40 may be formed by one layer of white ink. Also, the white ink of the shielding layer 40 may be cured immediately after landing on the adhesive layer 30.

[0029] In the subsequent steps S05 and S06, an image layer 50 is formed on the adhesive layer 30 and the concealing layer 40. In steps S05 and S06, a photo-curable process color ink is ejected by the printer 100 and irradiated with light to be fully cured, thereby forming the image layer 50 on the concealing layer 40. Specifically, in step S05, the process color ink is ejected by the printer 100 onto the concealing layer 40. In step S06, the process color ink ejected onto the concealing layer 40 is fully cured to form the image layer 50. FIG. 5 is a schematic diagram of the steps (steps S05 and S06) of forming the image layer 50. Steps S05 and S06 are the same as steps S01 and S02, except that the ejected ink is the process color ink and the color image specified by the manufacturer of the image transfer sheet 10 is formed by the process color ink.

[0030] In the subsequent steps S07 and S08, an overcoat layer 60 is formed on the image layer 50. In steps S07 and S08, a photocurable transparent ink is ejected by the printer 100 and irradiated with light to be fully cured, thereby forming the overcoat layer 60 on the image layer 50. Specifically, in step S07, the transparent ink is ejected by the printer 100 onto the image layer 50. In step S08, the transparent ink ejected onto the image layer 50 is fully cured to form the overcoat layer 60. FIG. 6 is a schematic diagram of the steps (steps S07 and S08) of forming the overcoat layer 60. Steps S07 and S08 are the same as steps S03 and S04, except that the ejected ink is transparent ink and the thickness of the overcoat layer 60 does not have to be as thick as the concealment layer 40. Since the transparent ink receives light after a lapse of time after landing on the image layer 50, it is leveled. As a result, the surface of the overcoat layer 60 becomes smooth, and the overcoat layer 60 has a gloss 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 with reduced gloss or may have a texture pattern aiming for a design effect. Also, the thickness of the overcoat layer 60 is not particularly limited and may be the same as or thicker than the concealment layer 40.

[0031] In step S09, an application sheet 70 is attached as a protective sheet onto the overcoat layer 60. The adhesive layer 71 of the application sheet 70 is adhered to the overcoat layer 60. Thereby, the image transfer sheet 10 is completed. The transferred image of the image transfer sheet 10 formed in this way is a color image specified by the manufacturer (however, if the specified image is a black-and-white image, it is a black-and-white image). Also, the image transfer sheet 10 is configured not to have an edge around the transferred image. However, for example, it is also possible to create an edge around the transferred image by the concealment layer 40.

[0032] [Image Transfer Method] Next, the procedure for transferring an image using the image transfer sheet 10 will be described. Although illustration is omitted, when a plurality of transfer images to be transferred to a plurality of locations are formed on one image transfer sheet 10, the image transfer sheet 10 may be cut into a plurality of parts each including one transfer image prior to transfer. FIG. 7 is a flowchart showing the procedure for image transfer by 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 upper surface of the application sheet 70 is wiped with a plate-shaped squeegee 200 (see FIG. 9). Thereby, the adhesive layer 30, the concealing layer 40, the image layer 50, and the overcoat layer 60 are made to adhere more closely. However, this operation may be performed at the time of manufacturing the image transfer sheet 10 (after step S09). Also, what wipes the upper surface of the application sheet 70 is not limited to the plate-shaped squeegee 200, and for example, it may be the user's hand, a baren, or the like. 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 after the release paper 20 is peeled off is brought into contact with the object to be transferred 5. In the subsequent step S14, with the adhesive layer 30 in contact with the object to be transferred 5, the application sheet 70 is pressed toward the adhesive layer 30. FIG. 9 is a schematic diagram of step S14. As shown in FIG. 9, in step S14, for example, by wiping the upper surface of the application sheet 70 with the squeegee 200, the application sheet 70 is pressed toward the adhesive layer 30. Thereby, the adhesive layer 30 adheres closely to the object to be transferred 5 and is adhered to the object to be transferred 5. In step S14, it is only necessary to make the adhesive layer 30 adhere closely to the object to be transferred 5. Therefore, in step S14, instead of wiping the application sheet 70, it may be simply pressed toward the object to be transferred 5.

[0035] As shown in FIG. 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. Thereby, the transfer of the image printed on the image transfer sheet 10 to the transfer target 5 is completed.

[0036] [Operation and Effect of the First Embodiment] As described above, the image transfer sheet 10 according to the present embodiment includes a release paper 20, an application sheet 70 having an adhesive layer 71, and an image layer 50 which is a layer in which a photocurable process color ink is completely cured and is provided between the release paper 20 and the application sheet 70. The image transfer sheet 10 further includes an overcoat layer 60 provided between the application sheet 70 and the image layer 50, and an adhesive layer 30 provided between the release paper 20 and the image layer 50. The overcoat layer 60 is a layer in which a photocurable transparent ink is completely cured, and is adhered to the adhesive layer 71 of the application sheet 70. The adhesive layer 30 is a layer in which a photocurable white ink is semi-cured, and has adhesiveness to the transfer target 5. In the production of such an image transfer sheet 10, the step of cutting around the image is unnecessary. Therefore, the image transfer sheet 10 according to the present embodiment can be easily and quickly produced. Further, such an image transfer sheet 10 can be produced using a general-purpose release paper 20 and ink, rather than a special material as described in Patent Document 1.

[0037] Furthermore, the image transfer sheet 10 according to the present embodiment includes an opaque shielding layer 40 that is a layer in which white ink is completely cured and is provided between the adhesive layer 30 and the image layer 50. Therefore, the color development of the image layer 50 formed on the shielding layer 40 can be made vivid regardless of the color of the object 5 to be transferred. In the present embodiment, the adhesive layer 30 is also formed of white ink. However, if the adhesive layer 30 is made thick, problems may occur in the transfer process. Therefore, the adhesive layer 30 is made thin and the shielding layer 40 is provided. Specifically, if the semi-cured adhesive layer 30 is made thick, the adhesive layer 30 is likely to protrude outside the image transfer sheet 10 when the image transfer sheet 10 is rubbed in the transfer process. Also, if the semi-cured adhesive layer 30 is made thick, when the image transfer sheet 10 is rubbed in the transfer process or when a force is applied to the image transfer sheet 10 after the transfer process is completed, the image layer 50 and the overcoat layer 60 are likely to move and shift on the object 5 to be transferred. Therefore, in the present embodiment, the adhesive layer 30 is made thin and the shielding layer 40 is formed to be thicker than the adhesive layer 30.

[0038] In the present embodiment, the ink forming the shielding layer 40 is white ink, but it may be other opaque special inks. For example, when the image transfer sheet 10 is desired to have a metallic finish, the ink forming the shielding layer 40 may be metallic ink. Also, in the present embodiment, the adhesive layer 30 is also formed of white ink in order to further enhance the shielding property. However, the ink forming the adhesive layer 30 may be a special ink other than white ink, for example, 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, thermosetting ink.

[0039] The image transfer sheet 10 according to this embodiment further includes an overcoat layer 60 in which the transparent ink is completely cured on the image layer 50. According to such a configuration, since the image layer 50 is protected by the overcoat layer 60, the durability of the image transfer sheet 10 is improved. Further, the image transfer sheet 10 according to this embodiment further includes an application sheet 70 attached on the overcoat layer 60. According to such a configuration, the application sheet 70 can protect the image transfer sheet 10 before transfer, and the storage and transportation of the image transfer sheet 10 are also facilitated. In this embodiment, as in step S14 of FIG. 7, the adhesive layer 30 is brought into contact with the object to be transferred 5, and the adhesive layer 30 is brought into close contact with the object to be transferred 5 by rubbing on the application sheet 70. Therefore, the application sheet 70 may be damaged by the operation of rubbing 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 object to be transferred 5 without damaging or soiling the image transfer sheet 10.

[0040] [Second Embodiment] In the second embodiment, the image transfer sheet has an adhesive layer in another form and does not have a concealment layer. Other configurations of the image transfer sheet according to the second embodiment are common to those of the first embodiment. In the following description of the second embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant descriptions are omitted or simplified.

[0041] [Configuration of Image Transfer Sheet] 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 of the first embodiment. It is preferable that the release paper 20 is excellent in availability such as general sticker base paper, but it is not limited thereto. In the present embodiment, the adhesive layer 31 is formed of a photocurable transparent ink. The adhesive layer 31 is a layer obtained by semi-curing the photocurable transparent ink on the release paper 20 and has adhesiveness to the object to be transferred 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] Here too, the adhesive layer 31 is configured to have the same shape as the image layer 50. Thus, as in the first embodiment, a transfer image without a border can be obtained. 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 the process color ink is completely cured on the adhesive layer 31. The overcoat layer 60 is a layer in which the transparent ink is completely cured on the image layer 50. Here, the image layer 50 and the overcoat layer 60 are the same as those of the first embodiment. However, the image layer 50 only needs to be a layer in which the process color ink is completely cured on the adhesive layer 31, and the ink used and its thickness are not particularly limited. The overcoat layer 60 only needs to be a layer in which the transparent ink is completely cured on the image layer 50, and the ink used and its thickness are also not limited. The application sheet 70 also has an adhesive layer 71 and is not particularly limited as long as it functions as a protective sheet.

[0045] [Method for producing an image transfer sheet] The method for manufacturing the image transfer sheet 11 according to the second embodiment will be described below. FIG. 12 is a flowchart showing the manufacturing procedure of the image transfer sheet 11 according to the second embodiment. As shown in FIG. 12, in manufacturing the image transfer sheet 11 according to the present embodiment, first, in step S21, a photocurable transparent ink is ejected by the printer 100 onto the release paper 20. 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 layer 31 having adhesiveness. 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 being leveled after landing. The adhesive layer 31 may be formed of a single layer of transparent ink, or may be formed by laminating a plurality of layers of transparent ink.

[0046] In the subsequent step S23, process color ink is ejected by the printer 100 onto the adhesive layer 31. In step S24, the process color ink ejected onto the adhesive layer 31 is completely cured to form the image layer 50.

[0047] In step S25, transparent ink is ejected by the printer 100 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 with a gloss finish, or may be formed with a matte finish as required. Further, the overcoat layer 60 may have a texture pattern aiming at 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 thus the description thereof is omitted. FIG. 13 is a schematic cross-sectional view of the image transfer sheet 11 after the image transfer to the object to be transferred 5 is completed. As shown in FIG. 13, after the image transfer is completed, the adhesive layer 31 of the image transfer sheet 11 is adhered to the object to be transferred 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 the application sheet 70 are removed.

[0049] [Operational Effects of the Second Embodiment] As described above, the image transfer sheet 11 according to the present embodiment includes a release paper 20, an adhesive layer 31 which is a layer in which a photocurable transparent ink is semi-cured on the release paper 20 and has adhesiveness, an image layer 50 in which process color ink is fully cured on the adhesive layer 31, an overcoat layer 60 in which transparent ink is fully cured on the image layer 50, and an application sheet 70 attached on the overcoat layer 60. Such an image transfer sheet 11 can also be easily and quickly manufactured without using special materials, similar to the image transfer sheet 10 according to the first embodiment. In the image transfer sheet 11 according to the present embodiment, the adhesive layer 31 is transparent, and the image layer 50 is formed on the transparent adhesive layer 31. Since the image transfer sheet 11 according to the second embodiment has fewer printing layers than the image transfer sheet 10 according to the first embodiment, it can be manufactured more easily and quickly than the image transfer sheet 10 according to the first embodiment. When the influence of the color of the object to be transferred 5 is not particularly problematic, or when it is desired to show through the color of the object to be transferred 5 for a more natural finish, the image transfer sheet 11 according to the present embodiment can be preferably used. For example, when the object to be transferred 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] Note that the ink forming the adhesive layer 31 does not have to be a transparent photocurable ink, and for example, an opaque photocurable ink may be used. The ink forming the adhesive layer 31 may be, for example, a photocurable white ink.

[0051] [Other Embodiments] Some preferred embodiments of the present invention have been described above. However, the above-described embodiments are merely examples, and the present invention can be implemented in various other forms.

[0052] For example, in the above-described embodiment, the image transfer sheet had an overcoat layer on the image layer and further had a protective sheet attached to the overcoat layer. However, it may not have an overcoat layer and a protective sheet. When the image transfer sheet includes a protective sheet, the protective sheet may be attached directly on 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. For example, it may be an overcoat layer made of a metallic ink layer or a white ink layer that is partially formed on the image layer and imparts a design effect.

[0053] Also, in the above-described embodiment, the image transfer sheets 10 and 11 were produced by a flatbed type printer 100 in which a flatbed 110 on which a printing object is placed moves. However, they may be produced by another type of printer, for example, a roll-to-roll type printer that performs printing while feeding a roll-shaped recording medium. In that case, the recording medium attached to the roll-to-roll type printer may be a release paper wound in a roll shape.

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

Explanation of Reference Numerals

[0055] 5 Object to be Transferred 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 Concealing Layer 50 Image Layer 60 Overcoat layer 70 Application sheet (protective sheet) 100 Inkjet printer

Claims

1. A release paper, a protective sheet having an adhesive layer, a layer in which a photocurable process color ink is fully cured, an image layer provided between the release paper and the protective sheet, a layer in which a photocurable transparent ink is fully cured, an overcoat layer provided between the protective sheet and the image layer and adhered to the adhesive layer of the protective sheet, a layer in which a photocurable opaque ink is semi-cured, an adhesive layer having adhesiveness to a transfer object and provided between the release paper and the image layer, a layer in which the opaque ink is fully cured, an opaque concealment layer provided between the adhesive layer and the image layer, and an image transfer sheet.

2. The thickness of the concealment layer is greater than the thickness of the adhesive layer, The image transfer sheet according to Claim 1.

3. A step of discharging a photocurable opaque ink by an inkjet printer, irradiating the opaque ink with light to semi-cure it, and forming an adhesive layer having adhesiveness to a transfer object on the release paper, A step of discharging a photocurable process color ink by an inkjet printer, irradiating the process color ink with light to fully cure it, and forming an image layer above the adhesive layer, A step of discharging the opaque ink by an inkjet printer and irradiating the opaque ink with light to fully cure it to form an opaque concealment layer on the adhesive layer after the step of forming the adhesive layer and before the step of forming the image layer, A step of discharging a photocurable transparent ink by an inkjet printer, irradiating the transparent ink with light to fully cure it, and forming an overcoat layer above the image layer, A step of adhering the adhesive layer of a protective sheet having an adhesive layer to the overcoat layer, A step of peeling the release paper from the adhesive layer, A step of bringing the adhesive layer after the release paper is peeled into contact with a transfer object, A step of pressing the protective sheet toward the adhesive layer while the adhesive layer is in contact with the transfer object, A step of peeling the protective sheet from the overcoat layer, and An image transfer method including the above steps.

Images