Method and apparatus for producing transfer sheets

Abstract

To provide a method for producing transfer sheets with excellent transferability to media with large irregularities. [Solution] A method for producing a transfer sheet, characterized by applying a first liquid to a substrate to form an image, applying a hot melt binder to the image, then applying a second liquid and the hot melt binder in this order, and heating the hot melt binder to which the first liquid has adhered and the hot melt binder to which the second liquid has adhered to form a transfer image layer.

Description

Technical Field

[0001] The present invention relates to a method for producing a transfer sheet and a transfer sheet production apparatus.

Background Art

[0002] There is known a technique for producing a transfer sheet by applying ink by inkjet onto a film, printing an image, sprinkling a powder that melts by heat, causing the powder to absorb the ink, and then applying heat to melt the powder.

[0003] For example, Patent Document 1 discloses that by including an antistatic agent in at least one layer of the layers constituting the transfer sheet, printing unevenness due to charging can be reduced.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the transfer sheet obtained by the conventional method, there has been a problem that it is not suitable for transfer to a medium having large irregularities because the thickness of the transfer image layer is insufficient compared to the thickness of the transfer image layer.

[0005] An object of the present invention is to provide a method for producing a transfer sheet excellent in transferability to a medium having large irregularities. <00000​​​​​​​​​​​​According to the present invention, it is possible to provide a method for producing a transfer sheet that has excellent transferability to media with large irregularities. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of a method for producing a transfer sheet using conventional technology. [Figure 2] Figure 2 is a schematic diagram showing the transfer of a transfer sheet to fabric using conventional technology. [Figure 3] Figure 3 is a schematic diagram showing an example of a transfer sheet manufacturing method according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic diagram showing the transfer of a transfer sheet to fabric using the transfer sheet manufacturing method according to one embodiment of the present invention. [Figure 5] Figure 5 is a schematic diagram showing another example of a transfer sheet manufacturing method according to one embodiment of the present invention. [Figure 6] Figure 6 is a flowchart showing the step of measuring the thickness of the transfer image layer in a transfer sheet manufacturing method according to one embodiment of the present invention. [Figure 7] Figure 7 is a schematic diagram showing an example of a transfer sheet manufacturing apparatus according to one embodiment of the present invention. [Figure 8] Figure 8 is a schematic diagram showing another example of a transfer sheet manufacturing apparatus according to one embodiment of the present invention. [Figure 9] Figure 9 is a schematic diagram showing another example of a transfer sheet manufacturing apparatus according to one embodiment of the present invention. [Figure 10] Figure 10 is an overall control block diagram of a transfer sheet manufacturing apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] First, we will explain the problems of the conventional technology using Figures 1 and 2.

[0010] Figure 1 is a schematic diagram showing an example of a method for producing a transfer sheet using conventional technology. The process for producing the transfer sheet is as follows: (1) Ink 11 is applied to the film F to form an image. (2) Apply the hot melt binder 12 to the image. (3) The applied hot melt binder 12 absorbs the attached ink 11. (4) The hot melt binder 13 that has absorbed the ink is melted by heating to form the transfer image layer 14.

[0011] Here, the hot melt binder is a resin that melts when heated, and for example, a powdered resin can be used. After the hot melt binder powder absorbs the ink, it melts and integrates with the ink when heated, forming a transfer image layer.

[0012] Figure 2 is a schematic diagram showing the transfer of a transfer sheet to fabric using conventional technology. The transfer sheet with the transfer image layer 14 is placed on the target fabric M, and the image is transferred by heating and pressing. Finally, the transfer is completed by peeling off the film F.

[0013] As shown in Figure 2, when the thickness of the threads constituting the fabric M is greater than the thickness of the transfer image layer 14, large irregularities occur on the surface of the fabric M compared to the transfer image layer 14. In this case, the transfer image layer 14 may not be able to follow the irregularities on the surface of the fabric M, resulting in image loss due to the image being cut off or the color of the recessed areas sinking from the fabric surface. Furthermore, even if the transfer is successful, the adhesion to the fabric M may be weak, leading to problems such as the transferred image being prone to cracking or peeling.

[0014] In view of the above problems of the prior art, the inventors of the present invention have conducted intensive studies and found that a thick transfer image layer can be formed by applying ink (hereinafter also referred to as the first liquid) and a hot melt binder, and then further applying the second liquid and the hot melt binder thereon. Since the thickness of the transfer image layer is increased compared with the prior art, a transfer sheet excellent in transferability can be produced even when transferring to a medium with large unevenness.

[0015] Hereinafter, the method for manufacturing a transfer sheet and the transfer sheet manufacturing apparatus of the present invention will be described. Note that the present invention is not limited to the embodiments shown below, and can be modified within the scope that those skilled in the art can conceive, such as other embodiments, additions, corrections, deletions, etc., and is included in the scope of the present invention as long as the functions and effects of the present invention are exhibited in any aspect.

[0016] First, the method for manufacturing a transfer sheet of the present invention will be described with reference to FIGS. 3 to 6.

[0017] FIG. 3 is a schematic view showing an example of a method for manufacturing a transfer sheet according to an embodiment of the present invention. The process of manufacturing the transfer sheet in this embodiment is as follows. (1) Apply the first liquid 11 on the film F to form an image. (2) Apply a hot melt binder 12 on the image. (3) The applied hot melt binder 12 absorbs the adhered first liquid 11. (4) Further apply the second liquid 15 on the hot melt binder 13 that has absorbed the first liquid. (5) Apply the hot melt binder 12 further from above where the second liquid 15 is applied. (6) The applied hot melt binder 12 absorbs the adhered second liquid 15. (7) Melt the hot melt binder 13 that has absorbed the first liquid and the hot melt binder 16 that has absorbed the second liquid by heating to form a transfer image layer 14.

[0018] As a hot-melt binder, there are no particular restrictions as long as it is a resin that melts when heated, and it can be appropriately selected according to the purpose.

[0019] The first liquid is not particularly limited as long as it can form an image, and commonly used inkjet inks can be suitably used.

[0020] It is preferable to use transparent ink as the second liquid. By using transparent ink as the second liquid, it is possible to eliminate any influence on the color of the image.

[0021] Furthermore, it is preferable to use an ink that approximates the color of the media to be transferred as the second liquid. When transferring the transfer image layer, it is transferred to the fabric in the reverse order of the lamination process used when creating the transfer sheet, so the layer containing the second liquid becomes the base. Therefore, by using an ink that approximates the color of the media to be transferred as the second liquid, the influence on the color of the image after transfer can be reduced.

[0022] Furthermore, the final color tones of the image can be achieved by combining the first and second liquids. In this case, other liquids may also be used.

[0023] Methods for dispensing the first and second liquids include, but are not limited to, dispensing them using a liquid ejection head (inkjet head).

[0024] Methods for applying hot melt binder include, but are not limited to, dropping the hot melt binder from a powder box containing powdered hot melt binder.

[0025] Methods for heating the hot melt binder applied to the film include using a heater that heats either by contact or by non-contact. When heating by contact, a transfer sheet can be produced without damaging the transfer image layer by heating from the side opposite to the surface on which the transfer image layer is formed.

[0026] Figure 4 is a schematic diagram showing the transfer of a transfer sheet to a fabric using the transfer sheet manufacturing method according to one embodiment of the present invention. Compared to the conventional technology, the thickness of the transfer image layer 14 has been increased, making it easier to conform to fabrics with large irregularities.

[0027] Figure 5 is a schematic diagram showing another example of a transfer sheet manufacturing method according to one embodiment of the present invention. The process for manufacturing the transfer sheet in this embodiment is as follows. (1) The first liquid 11 is applied to the film F to form an image. (2) Apply the hot melt binder 12 to the image. (3) The applied hot melt binder 12 absorbs the first liquid 11 that has adhered to it. (4) The hot melt binder 13 that has absorbed the first liquid is melted by heating to form the transfer image layer 14. (5) A second liquid 15 is then applied to the transfer image layer 14. (6) After applying the second liquid 15, the hot melt binder 12 is then applied on top of it. (7) The applied hot melt binder 12 absorbs the attached second liquid 15. (8) The hot melt binder 16 that has absorbed the second liquid is melted by heating to increase the thickness of the transfer image layer 14.

[0028] Unlike the embodiment shown in Figure 4, the embodiment shown in Figure 5 involves heating after (3) to form the transfer image layer 14. Subsequently, the thickness of the transfer image layer 14 is increased by steps (5) to (8).

[0029] Steps (5) to (8) in Figure 5 may be repeated. By applying the second liquid and the hot melt binder one or more times, an even thicker transfer image layer can be formed, further improving the ability to conform to the unevenness of the fabric to which the image is transferred.

[0030] The transfer sheet manufacturing method of the present invention may include a step of measuring the thickness of the transfer image layer. Figure 6 is a flowchart showing the step of measuring the thickness of the transfer image layer in a transfer sheet manufacturing method according to one embodiment of the present invention.

[0031] In step S1, the distance sensor (thickness sensor) measures the distance to the substrate surface and the distance to the transfer image layer surface, and calculates the thickness of the transfer image layer from the difference in distances.

[0032] In step S2, it is determined whether the thickness of the transfer image layer calculated in step S1 is equal to or greater than a predetermined thickness. If it is equal to or greater than the predetermined thickness, the transfer sheet is prepared. If it is less than the predetermined thickness, the process proceeds to steps S3 to S5.

[0033] In step S3, a second liquid is applied to the transfer image layer, and in step S4, a hot melt binder is applied to absorb the second liquid. Then, in step S5, the hot melt binder is melted by heating to increase the thickness of the transfer image layer.

[0034] After step S5, the process returns to step S1 to recalculate the thickness of the transfer image layer, and in step S2, it is determined whether it is greater than or equal to a predetermined thickness. By repeating the above process, a transfer sheet with a transfer image layer thickness greater than or equal to a predetermined thickness can be produced.

[0035] The process includes a step of measuring the thickness of the transfer image layer, and by repeatedly applying the second liquid and the hot melt binder until the thickness of the transfer image layer exceeds a predetermined thickness, a transfer sheet with excellent transferability can be stably produced.

[0036] Next, the transfer sheet manufacturing apparatus of the present invention will be described using Figures 7 to 10.

[0037] Figure 7 is a schematic diagram showing an example of a transfer sheet manufacturing apparatus according to one embodiment of the present invention.

[0038] The transfer sheet manufacturing apparatus 1 includes a liquid discharge head 31 as a first liquid application unit and a liquid application unit as a second liquid application unit, and a powder box 61 as a hot melt binder application unit.

[0039] Below, we will describe in detail an example of the operation of the transfer sheet manufacturing apparatus 1 shown in Figure 7.

[0040] The base film F is wound onto a film supply roll 401, and the film F supplied from the film supply roll 401 is transported below the head while being pulled along the guide plate 42 by the rotation of the suction roller 402. The suction roller 402 has fine holes on its surface, and the film F is attracted by applying negative air pressure (vacuum) to these holes.

[0041] The carriage 21, equipped with a liquid ejection head 31, is driven along a guide rod 22 and ejects a first liquid from the liquid ejection head 31 onto the film F on the guide plate 42 at an appropriate timing according to the printed image data, thereby forming an image on the film F. The carriage 21 is equipped with a head capable of ejecting at least two types of liquids, or multiple heads are configured to eject at least two types of liquids.

[0042] The film F on which the image has been formed passes under the powder box 61. At this time, hot melt binder (hereinafter referred to as powder) is dropped from the powder box 61 onto the film F, absorbing the first liquid on the film F and remaining on the film F. The film F is vibrated by being struck by the downstream dusting roller 63, and any excess powder (mainly powder that has not absorbed the first liquid) is brushed off into the excess powder receiver 62.

[0043] Subsequently, the film supply roll 401, suction roller 402, and film recovery roll 404 are rotated in opposite directions to transport the film F towards the film supply roll 401. During rewinding, the upstream dusting roller 63 is operated to dust off excess powder, reducing the amount of excess powder flowing towards the head. After that, the film F is transported again towards the film recovery roll 404, and the second liquid is discharged from the liquid discharge head 31 onto the powder on the film F that has absorbed the first liquid.

[0044] After that, as with the first application of liquid, powder is dropped from the powder box 61, excess powder is removed by the downstream dusting roller 63, and the powder is heated from above by the heater 71 while it is on the conveyor belt 403 to melt it and form the transfer image layer, thus completing the transfer sheet.

[0045] By forming a thick transfer image layer through the above process, a transfer sheet with excellent conformability to fabrics with large irregularities can be produced.

[0046] Figures 8 and 9 are schematic diagrams showing another example of a transfer sheet manufacturing apparatus according to one embodiment of the present invention.

[0047] The transfer sheet manufacturing apparatus 1 shown in Figure 8 has a configuration in which two image-forming units are connected in series, each performing three operations: (1) liquid application, (2) powder application, and (3) heating by a heater. A liquid discharge head 31a mounted on a carriage 21a driven by a guide rod 22a discharges a first liquid, and a liquid discharge head 31b mounted on a carriage 21b driven by a guide rod 22b discharges a second liquid. In the configuration shown in Figure 7, it was necessary to rewind the film F, whereas in the configuration shown in Figure 8, the film F only needs to be fed in one direction at all times, thus increasing the productivity of transfer sheets.

[0048] Furthermore, the image-forming section for applying the second liquid and the powder box 61 may be increased and connected in a continuous configuration. By applying the second liquid and the hot melt binder one or more times, an even thicker transfer image layer can be formed, further improving the ability to conform to the unevenness of the fabric to which the image is transferred.

[0049] The transfer sheet manufacturing apparatus 1 shown in Figure 9 has a guide plate 42 and a distance sensor (thickness sensor) 81 mounted on the downstream side of the conveyor belt 403.

[0050] There are no particular restrictions on the distance sensor 81, and it can be appropriately selected depending on the purpose, but examples include optical types such as lasers and LEDs. The distance to the surface of the film F and the distance to the surface of the transfer image layer are measured by the distance sensor 81, and the thickness of the transfer image layer is calculated from the difference in distances.

[0051] If the thickness of the transfer image layer calculated by the distance sensor 81 is less than a predetermined thickness, the film F is rewound in the direction of the film supply roll 401, and the second liquid is applied, the powder is applied, and heating is performed again to increase the thickness of the transfer image layer. By repeating the above steps, a transfer sheet with a transfer image layer thickness of or greater than the predetermined thickness can be produced, as shown in Figure 6.

[0052] The transfer sheet manufacturing method of the present invention can be suitably carried out by using the transfer sheet manufacturing apparatus shown in Figures 7 to 9.

[0053] Figure 10 is an overall control block diagram of a transfer sheet manufacturing apparatus according to one embodiment of the present invention.

[0054] The transfer sheet manufacturing apparatus 1 shown in Figure 10 includes an operation panel 4, a control unit 5, a carriage 21, a main scanning drive mechanism 20, a head drive unit 30, a sub-scanning drive mechanism 40, a transport unit 41, a powder box 61, a heater 71, and a distance sensor 81.

[0055] The control unit 5 includes a controller board 50, a printing control board 51, a main scanning control board 52, a sub-scanning control board 53, a powder box control board 54, and a heater control board 55.

[0056] The controller board 50 is the main control unit and includes a CPU (Central Processing Unit) 501, ROM (Read Only Memory) 502, RAM (Random Access Memory) 503, NVRAM (Non-Volatile Random Access Memory) 504, and the like.

[0057] The CPU 501 is connected to the control panel 4 for inputting and displaying information necessary for the device, and controls the entire device. The ROM 502 stores programs executed by the CPU 501 and other fixed data. The RAM 503 temporarily stores image data, etc. The NVRAM 504 is a rewritable non-volatile memory that retains data even when the device power is turned off.

[0058] The controller board 50 is further equipped with an I / F 505 and an I / O 506. The I / F 505 is responsible for sending and receiving signals. The I / O 506 acquires information from the distance sensor 81 and extracts information used to control each part of the main body of the transfer sheet manufacturing apparatus 1. The controller board 50 performs integrated control of image formation and determines the head drive profile, main scan drive profile, sub scan drive profile, powder box drive profile, and heater drive profile.

[0059] Furthermore, the control unit 5 includes a printing control board 51, a main scanning control board 52, a sub-scanning control board 53, a powder box control board 54, and a heater control board 55.

[0060] The printing control board 51 controls the head drive unit 30 based on the head drive profile, generates a drive waveform to drive the liquid discharge head 31, which is the liquid application unit, to discharge the first liquid and the second liquid, and outputs image data and various related data that selectively drive the pressure generating means of the liquid discharge head 31.

[0061] The main scanning control board 52 controls the main scanning drive mechanism 20 based on the main scanning drive profile, and drives the carriage 21, including the liquid discharge head 31, in the main scanning direction.

[0062] The sub-scanning control board 53 controls the sub-scanning drive mechanism 40 based on the sub-scanning drive profile and drives the film supply roll 401, suction roller 402, transport belt 403, film recovery roll 404, etc. included in the transport unit 41 to transport the substrate in the sub-scanning direction.

[0063] The powder box control board 54 controls the operation of the powder box 61 in which it dispenses powder, based on the powder box drive profile.

[0064] The heater control board 55 controls heating by the heater 71 based on the heater drive profile.

[0065] By operating the transfer sheet manufacturing apparatus 1 with the above control, it is possible to manufacture a transfer sheet with excellent transferability to media with large irregularities.

[0066] The embodiments of the present invention are, for example, as follows. <1> This method for producing a transfer sheet is characterized by applying a first liquid to a substrate to form an image, applying a hot melt binder to the image, then applying a second liquid and the hot melt binder in that order, and then heating the hot melt binder to which the first liquid has adhered and the hot melt binder to which the second liquid has adhered to form a transfer image layer. <2> The second liquid is characterized by being a transparent ink. <1> This is the method for preparing the transfer sheet described in [reference]. <3> The second liquid is characterized by being an ink of an approximate color to the color of the media to which it is transferred. <1> This is the method for preparing the transfer sheet described in [reference]. <4> The method is characterized by further applying the second liquid and the hot melt binder one or more times. <1> from <3> This is a method for preparing a transfer sheet as described in any one of the items. <5> The method is characterized by measuring the thickness of the transfer image layer and repeatedly applying the second liquid and the hot melt binder until the thickness of the transfer image layer exceeds a predetermined thickness. <1> from <4> This is a method for preparing a transfer sheet as described in any one of the items. <6> A first liquid dispensing unit that dispenses a first liquid, A second liquid dispensing unit that dispenses a second liquid, A hot melt binder application unit that applies hot melt binder, The device comprises a heater for heating the hot melt binder, This transfer sheet manufacturing apparatus is characterized by forming an image by applying the first liquid onto a substrate, applying the hot melt binder onto the image, then applying the second liquid and the hot melt binder in that order, and then heating the hot melt binder to which the first liquid has adhered and the hot melt binder to which the second liquid has adhered to form a transfer image layer. <7> The second liquid is characterized by being a transparent ink. <6> This is the transfer sheet manufacturing apparatus described above. <8> The second liquid is characterized by being an ink of an approximate color to the color of the media to which it is transferred. <6> This is the transfer sheet manufacturing apparatus described above. <9> The method is characterized by further applying the second liquid and the hot melt binder one or more times. <6> from <8> This is a transfer sheet manufacturing apparatus as described in any one of the items. <10> The system further includes a thickness sensor for measuring the thickness of the aforementioned transfer image layer, The method is characterized by repeatedly applying the second liquid and the hot melt binder until the thickness of the transfer image layer exceeds a predetermined thickness. <6> from <9> This is a transfer sheet manufacturing apparatus as described in any one of the items.

[0067] The aforementioned <1> from <5> The method for producing a transfer sheet described above, <6> from <10> The transfer sheet manufacturing apparatus described above can solve the aforementioned problems of the conventional method and achieve the objectives of the present invention. [Explanation of symbols]

[0068] 1. Transfer sheet manufacturing apparatus 11. Ink (First Liquid) 12 Hot Melt Binder 13. Hot melt binder that has absorbed the ink (first liquid) 14. Transfer image layer 15. The second liquid 16. Hot melt binder that has absorbed the second liquid. 31. Liquid dispensing head (first liquid dispensing section and second liquid dispensing section) 61 Powder box (hot melt binder application section) 71 Heater F Film (substrate) M Fabric (transfer media) [Prior art documents] [Patent Documents]

[0069] [Patent Document 1] Japanese Patent Publication No. 2001-213048

Claims

1. A method for producing a transfer sheet, characterized by applying a first liquid to a substrate to form an image, applying a hot melt binder to the image, then applying a second liquid and the hot melt binder in that order, and heating the hot melt binder to which the first liquid has adhered and the hot melt binder to which the second liquid has adhered to form a transfer image layer.

2. The method for producing a transfer sheet according to claim 1, characterized in that the second liquid is a transparent ink.

3. The method for producing a transfer sheet according to claim 1, characterized in that the second liquid is an ink of an approximate color to the color of the media to which the transfer is to be made.

4. The transfer sheet manufacturing method according to claim 1, characterized in that the second liquid and the hot melt binder are applied one or more times.

5. The method for producing a transfer sheet according to claim 1, characterized in that the thickness of the transfer image layer is measured, and the application of the second liquid and the hot melt binder is repeated until the thickness of the transfer image layer is equal to or greater than a predetermined thickness.

6. A first liquid dispensing unit that dispenses a first liquid, A second liquid dispensing unit that dispenses a second liquid, A hot melt binder application unit that applies hot melt binder, The device comprises a heater for heating the hot melt binder, A transfer sheet manufacturing apparatus characterized by applying the first liquid to a substrate to form an image, applying the hot melt binder to the image, then applying the second liquid and the hot melt binder in this order, and heating the hot melt binder to which the first liquid has adhered and the hot melt binder to which the second liquid has adhered to form a transfer image layer.

7. The transfer sheet manufacturing apparatus according to claim 6, characterized in that the second liquid is a transparent ink.

8. The transfer sheet manufacturing apparatus according to claim 6, characterized in that the second liquid is an ink of an approximate color to the color of the media to be transferred.

9. The transfer sheet manufacturing apparatus according to claim 6, characterized in that the second liquid and the hot melt binder are applied one or more times further.

10. The system further includes a thickness sensor for measuring the thickness of the aforementioned transfer image layer, The transfer sheet manufacturing apparatus according to claim 6, characterized in that the application of the second liquid and the hot melt binder is repeated until the thickness of the transfer image layer is equal to or greater than a predetermined thickness.

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