Foil thermal transfer apparatus

Abstract

To carry out thermal transfer of a foil by using a compact foil thermal transfer apparatus employing a small-diameter heat roller having a relatively low rigidity onto an uneven paper after subjected to printing with a toner by a laser printer.SOLUTION: In order to improve quality of poor thermal transfer of a foil due to deflection of a heat roller when carrying out thermal transfer of the foil, a first pressure roller and a second pressure roller are disposed at a position where the heat roller is sandwiched, and the second pressure roller and the heat roller are configured to serve two purposes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for thermally transferring foil from a foil film to copy paper or the like onto which toner has been thermally transferred. This relates to a foil thermal transfer device. [Background technology]

[0002] The following Patent Documents 1 and 2 disclose a foil thermal transfer method in which paper on which characters have been printed with toner using a laser printer is placed on a foil film and thermocompressed, and then the paper and foil film are peeled off, thereby adhering foil only to the areas of the paper where the characters are printed. Furthermore, Patent Documents 3 and 4 below disclose methods for efficiently separating a transfer foil layer from a carrier layer of a foil film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 8-2098 [Patent Document 2] Patent Publication No. 2000-15944 [Patent Document 3] Patent 6314988 [Patent Document 4] Special Publication 2016-502473 Summary of the Invention [Problem to be solved by the invention]

[0004] Recent advances in laser printer printing technology have made it possible to transfer toner onto paper with unevenness of several tens of micrometers. Furthermore, market needs for decorative features have led to a demand for the ability to transfer foil onto paper with unevenness printed by a laser printer.

[0005] Generally, devices for thermally transferring foil onto smooth paper on which characters or the like have been printed with toner by a laser printer are commercially available and widely used. However, when using a foil thermal transfer device capable of thermally transferring foil onto smooth paper to adhere foil film to textured paper printed with toner, there was a drawback in that it was difficult to ensure sufficient adhesion of the foil film to the recesses of the textured paper, resulting in insufficient adhesion of the foil.

[0006] For this reason, commercially available foil thermal transfer devices in recent years have increased the temperature and pressure used to heat-press the foil film and paper together, softening the foil film with heat and elastically deforming the rubber on the outer periphery of the heat roller with high pressure, allowing the foil of the foil film to adhere to the bottom of the recesses, thereby allowing thermal transfer of foil even onto paper with unevenness of several tens of microns.

[0007] However, it is known that simply increasing the pressure in conventional foil thermal transfer devices can cause problems: Increasing the thermal transfer pressure in conventional devices increases the bending of the heat roller and pressure roller, causing an insufficient pressure near the center of the rollers in the longitudinal direction, resulting in insufficient adhesion of the foil film to the recesses in the textured paper, and insufficient thermal transfer of the foil in the recesses.

[0008] For this reason, in order to reduce the occurrence of deflection when high pressure is applied, it is necessary to increase the diameter of the roller to increase rigidity against longitudinal deflection, and to take measures to strengthen the rigidity of the entire device, such as increasing the strength of the frame.However, this inevitably results in the foil thermal transfer device becoming heavy and large, which limits the installation of the device and increases the cost. [Means for solving the problem]

[0009] In order to solve the above problems, the foil thermal transfer device disclosed herein is a foil thermal transfer device that thermally transfers a foil film onto a substrate, and is equipped with a heat roller having an elastic body on its outer periphery, a heat source arranged near the radial center of the heat roller, a first pressure roller that pinches the substrate and foil film between itself and the heat roller, a second pressure roller arranged in a position where it pinches the heat roller radially with the first pressure roller, a heat source arranged near the radial center of the second pressure roller, and a lifting device that raises and lowers the first pressure roller.

[0010] It is preferable that there is a gap between the heat roller and the second pressure roller before the rollers are brought into pressure contact with each other. It is preferable to provide a gap between the heat roller and the first pressure roller that can be freely opened and closed. It is preferable that the first pressure roller and the second pressure roller have substantially the same longitudinal bending strength.

[0011] The number of second pressure rollers may be two or more. It is also preferable to provide a heat source at the center in the radial direction of the first pressure roller. It is also preferable that the outer periphery of the heat roller has an elastic body with a thermal conductivity of 1 to 1.3 W / m·K. [Effects of the Invention]

[0012] With this configuration, foil thermal transfer is possible when the longitudinal deflection of the heat roller is small, without relying on the longitudinal deflection strength of the heat roller.As a result, even when a relatively small diameter heat roller is used, by applying a large load and increasing the contact pressure, foil thermal transfer can be performed sufficiently even on substrates that are relatively difficult to use for foil thermal transfer, such as paper with unevenness.

[0013] According to this configuration, foil thermal transfer is possible when the longitudinal deflection of the heat roller is small, without relying on the longitudinal deflection strength of the heat roller. As a result, a relatively small diameter heat roller can be used, making it possible to make the device smaller and lighter, and reducing the manufacturing costs and installation space of the foil thermal transfer device.

[0014] The pressure contact position between the heat roller and the first pressure roller can be freely adjusted, which has the effect of enabling foil thermal transfer even on thick substrates. In the preparation stage before the foil thermal transfer, the rollers are spaced apart, which has the effect of preventing the rubber on the outer periphery of the heat roller from being deformed. Furthermore, by using the heating roller and the second pressure roller together, it is possible to reduce the manufacturing costs and installation space of the foil thermal transfer device. Since it is possible to select a material with good thermal conductivity for the second pressure roller, there is an effect that it is possible to heat the heat roller efficiently.

[0015] When there are a plurality of second pressure rollers, the heat roller can be heated more efficiently than when there is only one. By providing a heat source at the center in the radial direction of the first pressure roller, it is possible to easily set the temperature of the outer periphery of the first pressure roller to an optimum temperature for thermal transfer. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a side view showing a state before the rollers are pressed together according to the first embodiment. [Figure 2] 1 is a diagram showing a state in which the rollers are pressed together according to the first embodiment (side view). [Figure 3] 1 is a view showing a state in which the rollers are pressed together according to the first embodiment (front view). [Figure 4] FIG. 10 is a diagram showing a state in which rollers are pressed together according to a conventional example (front view). [Figure 5] 10 is a view showing a state in which the rollers are pressed together according to the second embodiment (front view). [Figure 6] 10 is a diagram showing a state in which rollers are pressed together according to a conventional example (side view). [Figure 7] 1 is a diagram showing a state in which the rollers are pressed together according to the first embodiment (side view). [Figure 8] 10 is a diagram showing a state in which rollers are pressed together according to a conventional example (side view). [Figure 9] Pressure contact diagram when thermally transferring foil onto textured paper (partially enlarged view) DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, there are cases where more detailed explanation than necessary is omitted. For example, there are cases where detailed explanation of already well-known matters and redundant explanation of substantially the same configuration are omitted. This is because This is to avoid unnecessary redundancy in the following explanation and to make it easier for those skilled in the art to understand. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0018] Next, before describing the foil thermal transfer device 100 of this embodiment, problems with the conventional foil thermal transfer device 100 will be described with reference to Figures 4, 6, and 9. Here, with regard to the symbols used in the following description of the conventional foil thermal transfer device and the foil thermal transfer device of this embodiment, which will be described later, similar members will be assigned the same symbols unless there is a particular need to distinguish them.

[0019] Fig. 6 is a schematic diagram of an example of a conventional foil thermal transfer device 100, and Fig. 4 is an explanatory diagram of the deflection of the heat roller 1 and pressure roller 5 when they are pressed together. Fig. 4 exaggerates the deflection, and there are cases where gaps occur near the longitudinal center of the rollers due to the relationship between the load and the rigidity of each roller, and there are also cases where the gaps cannot be detected visually.

[0020] 4 and 6 will not be described in detail as they overlap with the descriptions of Embodiments 1 and 2 of the invention disclosed below. However, a major difference between the conventional example and Embodiments 1 and 2 of the invention is that the conventional example has one pressure roller, whereas Embodiments 1 and 2 of the invention have two pressure rollers, with the two pressure rollers positioned to pinch heat roller 1. Also, as shown in Figure 4, heat roller 1 and pressure roller 5 are bent like a bow, and there are cases where a gap occurs near the center of the rollers in the longitudinal direction, and cases where the bending is absorbed by deformation of heat roller rubber 1b on the outer periphery of heat roller 1, but in either case, a drop in pressure occurs near the center of the rollers in the longitudinal direction.

[0021] Next, a description will be given with reference to FIG. FIG. 9 is a partially enlarged explanatory view of the thermal transfer of foil by a foil film when the substrate 13 is, for example, textured paper and toner is thermally transferred onto the surface by a laser printer. The figure shows a state in which a foil film 12 and a substrate 13, a piece of paper printed with uneven toner, are superimposed between a heat roller 1 and a pressure roller 5 (not shown), and pressure and heat are applied. This is intended to adhere a foil layer 12u of the foil film to the substrate 13. However, as shown in Figure 9, the foil film 12 has difficulty coming into contact with the recesses 13a of the substrate 13, a piece of paper printed with uneven toner, and as a result, the foil layer 12u of the foil film is difficult to thermally transfer.

[0022] Therefore, conventionally, the pressure between the heat roller 1 and the pressure roller 5 (not shown) is increased to deform the heat roller rubber 1b and bring the foil film 12 into contact with the recesses 13a of the paper, and the temperature of the heat roller rubber 1b is further increased to soften the foil film 12, which also brings the foil film 12 into contact with the recesses 13a of the paper.

[0023] The pressure and temperature at which the foil film 12 comes into contact with the recesses 13a in the paper have various combination conditions depending on the mechanical and temperature characteristics of the heat roller rubber 1b, the foil film 12, and the textured paper that serves as the substrate 13. The conditions also differ depending on the depth and shape of the recesses and protrusions in the textured paper that serves as the substrate 13. For this reason, foil thermal transfer is performed experimentally to set the pressure and temperature conditions, and the type of paper on which foil thermal transfer can be performed is also selected.

[0024] Generally, when performing thermal transfer on paper with unevenness of about several tens of micrometers, the temperature of the heat roller rubber 1b is raised to about 180 to 200 degrees Celsius, from about 100 to 130 degrees Celsius for smooth paper. Also, the pressure between the heat roller 1 and pressure roller 5 is about 30 N / cm2 for smooth paper, but has traditionally been raised to about 100 N / cm2 for uneven paper.

[0025] Increasing the pressure increases the longitudinal deflection of the heat roller 1 and pressure roller 5, so in order to increase the rigidity of the heat roller 1 and pressure roller 5, the outer diameter of the rollers has been increased, making the device larger so that deflection is less likely to occur. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. (First embodiment of the invention) Hereinafter, the first embodiment will be described with reference to FIGS. [Example]

[0026] Fig. 1 shows a foil thermal transfer device 100. Fig. 1 shows the state before the rollers are pressed together. The outer circumferential surfaces of the heat roller 1 and the first pressure roller 5 are arranged to face each other. A gap indicated by d1 in the figure is provided between the heat roller 1 and the first pressure roller 5. The surfaces of the foil film 12 and the substrate 13 are arranged in this gap d1 so as to face the outer peripheral surfaces of the heat roller 1 and the first pressure roller 5.

[0027] The outer periphery of the heat roller 1 has heat roller rubber 1b. This heat roller rubber 1b is preferably silicone rubber, and it is desirable to add an additive to the silicone rubber to increase its thermal conductivity to 1 W / m·K or more. The first pressure roller 5 is often made of metal, preferably steel, but may also be made of metal such as aluminum. The heat roller 1 and first pressure roller 5 have heat roller bearings 1a and pressure roller bearings 5a at both ends in the longitudinal direction, respectively.

[0028] The cam 6 can rotate around a cam rotation axis 7 . The foil film 12 has a foil film foil layer 12u disposed on a foil film transfer layer 12t. The foil film 12 is positioned so that the foil film foil layer 12u faces the surface of the substrate 13 to be thermally transferred. The foil film foil layer 12u may be coated with a heat-activatable adhesive layer. A release layer may be disposed between the foil film transfer layer 12t and the foil film foil layer 12u to facilitate separation of the foil film foil layer 12u from the foil film transfer layer 12t. The second pressure roller 2 is preferably made of metal such as steel or aluminum, etc. The second pressure roller 2 has second pressure roller bearings 2a at both ends in the longitudinal direction.

[0029] The outer peripheral surface of the first pressure roller bearing 5a is in sliding contact with the outer peripheral surface of the cam 6 due to its own weight. The outer peripheral surface of the first pressure roller bearing 5a is also guided by a bearing guide C10, allowing it to freely move up and down in the vertical direction in the drawing. The heat roller bearing 1a is supported by a bearing guide B9 so that it does not fall off in the vertically downward direction from a predetermined position, and can be freely raised and lowered in the vertically upward direction by the bearing guide B9. The second pressure roller bearing 2a is supported by a bearing guide A8 so that it does not fall off in the vertically downward direction from a predetermined position, and can be freely raised and lowered in the vertically upward direction by the bearing guide A8. In addition, a compression coil spring 4 presses the second pressure roller bearing 2a against the bearing guide A8 via a pressing member 3.

[0030] In the above state, a gap d2 is provided between the outer circumferential surface of the second pressure roller 2 and the outer circumferential surface of the heat roller 1. The foil film 12 is unwound from an unwinding roller (not shown), wound around a foil film guide 11, and arranged to pass through the gap d1 between the heat roller 1 and the first pressure roller 5. Thereafter, the foil film is wound around a foil film separating member 15, and then wound around a winding roller (not shown). The following explanation will be given using Figure 2. FIG. 2 shows a state in which the rollers are in pressure contact with each other to transport the substrate 13 and foil film 12 in the direction of the arrow in the drawing.

[0031] When the cam 6 rotates around the cam shaft 7, the outer peripheral surface of the cam 6 comes into sliding contact with the outer peripheral surface of the first pressure roller bearing 5a. At this time, the first pressure roller bearing 5a is guided by the bearing guide C10, and the first pressure roller 5 is moved vertically upward in the figure. When the first pressure roller 5 is moved in the vertical direction in the figure, the outer circumferential surface of the first pressure roller comes into contact with the outer circumferential surface of the heat roller 1, moving the heat roller 1 in the vertically upward direction. When the heat roller 1 is moved vertically upward, the outer surface of the heat roller 1 abuts against the outer surface of the second pressure roller 2, and the second pressure roller 2 is moved vertically upward, so that the second pressure roller bearing 2a further moves the pressing member 3 vertically upward and compresses the compression spring 4.

[0032] Pressure is generated between the heat roller 1 and the first pressure roller 2 by the spring force generated by compressing the compression spring 4 . This pressure presses the foil film 12 against the substrate 13 to perform foil thermal transfer. The following explanation will be given using Figure 3. Figure 3 is a diagram illustrating the state of deflection of each roller when the rollers are pressed against each other as shown in Figure 2. In Figure 3, heat roller 1 shows a state in which there is almost no deflection in the longitudinal direction. This state occurs when the deflection strengths of the first pressure roller and the second pressure roller are roughly the same. In other words, even if the deflection strength of heat roller 1 is weak, this can be achieved by arranging two rollers with roughly the same deflection strength at the position that sandwiches heat roller 1.

[0033] Since there is little need to consider the deflection of the heat roller 1, it becomes easier to select the outer diameter of the heat roller relatively freely. The outer diameters of the first pressure roller and the second pressure roller in Figures 1 to 3 are different, but in the case of Figures 1 to 3, when the first pressure roller 5 is made of steel and the second pressure roller 2 is made of aluminum, the Young's modulus of iron and aluminum is significantly different, so the outer diameter of the second pressure roller made of aluminum may be made larger. Young's Modulus Example Carbon steel S45C Young's modulus 205 GPa Aluminum alloy A5052 Young's modulus 70.6 GPa Up to now, we have shown the case where the longitudinal deflection strengths of the first pressure roller 5 and the second pressure roller 2 are approximately the same, but the deflection strengths may differ within a range that does not cause any problems when performing foil thermal transfer. (Embodiment 2 of the invention) Hereinafter, the first embodiment will be described with reference to FIGS. [Example]

[0034] 5 and 6 show the case where the first pressure roller 5 and the second pressure roller 2 are made of the same material, and the roller outer diameters are made approximately the same to make the bending strengths approximately the same. The other configurations are the same as those of the first embodiment. According to the second embodiment, it is also possible to manufacture the first pressure roller 5 and the second pressure roller 2 from the same material.

[0035] (Explanation regarding heat conduction in the first and second embodiments of the invention) The heat required for foil thermal transfer in the first and second embodiments will be described below. In FIG. 2, a halogen heater A16 is arranged at the center of the heat roller 1, a halogen heater C18 is arranged at the center of the first pressure roller 5, and a halogen heater B17 is arranged at the center of the second pressure roller 2.

[0036] Normally, the halogen heater A16 located in the center of the heat roller 1 is turned on to heat the rubber of the heat roller rubber 1b of the heat roller 1. When the foil film 12 and substrate 13 are moved in the direction of the arrow in Figure 2, the heat of the heat roller rubber 1b is absorbed by the foil film 12 and substrate 13, causing the temperature to drop, so the halogen heater A16 is turned on to heat it. At this time, heat is conducted through the core metal part of the heat roller 1 and the heat roller rubber 1b, so when adjusting the temperature based on the temperature measurement value of the surface temperature sensor (not shown) of the heat roller rubber 1b, a delay in heat conduction occurs, making it difficult to control the temperature with precision.

[0037] Therefore, as shown in Patent 6314988, the surface of the heat roller rubber 1b has been directly heated with a halogen heater, or as shown in Figure 8, a heat roller 19 with a halogen heater D20 located in the center has been brought into contact with the heat roller 1 for heating. The heat roller 19 is often made of aluminum, a material with high thermal conductivity.

[0038] Figures 1 and 2 in embodiment 1 of the present invention illustrate an embodiment in which a halogen heater is placed in the center of the second pressure roller 2, and the second pressure roller 2 is made of a material such as aluminum that has high thermal conductivity but a relatively low Young's modulus.

[0039] Aluminum is used for the second pressure roller when a material with high thermal conductivity is desired. In other words, it can efficiently transfer heat generated by the halogen heater B17 located near the radial center of the second pressure roller to the heat roller rubber 1b located on the outer periphery of the heat roller 1. This efficiently replenishes the heat lost by the substrate 13 and foil film 12 when foil thermal transfer is performed continuously.

[0040] Thermal Conductivity Example Carbon steel S45C Thermal conductivity 45.0 W / m K Aluminum alloy A5052 Thermal conductivity 138 W / m K For the same reason, it is recommended to use silicone rubber with a thermal conductivity of 1 to 1.3 W / m·K as the material for the heat roller rubber 1b. The thermal conductivity of ordinary silicone rubber is about 0.2 W / m·K, but by adding inorganic fillers to silicone rubber, rubber materials with thermal conductivity increased to about 1 to 1.3 W / m·K are commercially available.

[0041] By using this rubber with high thermal conductivity, the heat generated by the halogen heater A16 located near the radial center of the heat roller 1 can be efficiently transferred to the heat roller rubber 1b, and the heat lost by the substrate 13 and foil film 12 can be efficiently replenished when foil thermal transfer is performed continuously. Furthermore, a halogen heater C18 is disposed near the radial center of the first pressure roller 5. The first pressure roller comes into contact with the substrate 13, which is paper printed with toner by a laser printer, during foil thermal transfer. It has been experimentally confirmed that the temperature of the first pressure roller 5 should be set to approximately 50°C to 100°C.

[0042] That is, if the temperature is too high, the toner melts and adheres to the substrate 13, preventing sufficient foil thermal transfer, while if the temperature is too low, the adhesion between the foil layer 12u of the foil film and the toner decreases, which is undesirable in terms of quality. (Explanation of the use of a thick substrate in the first and second embodiments of the invention) Furthermore, as shown in FIG. 7, by adjusting the rotation angle of the cam 6, it is possible to apply an appropriate pressure even if the thickness of the substrate 13 changes. Also, although Figures 1 and 2 show an example in which there is one second pressure roller 2, there may be multiple second pressure rollers, and the deflection strength and arrangement of the rollers may be appropriately selected so that deflection of the heat roller 1 does not generally occur. [Industrial Applicability]

[0043] The foil thermal transfer device according to the present disclosure can thermally transfer foil to a substrate with a large load and a large amount of heat. As a result, a compact device can be used to thermally transfer foil onto textured paper on which characters have been printed with toner by a laser printer, making the device applicable to all foil thermal transfer devices that use thermal transfer. [Explanation of symbols]

[0044] 1 Heat roller 1a Heat roller bearing 1b Heat roller rubber 2 Second pressure roller 2a Second pressure roller bearing 3 Pressing member 4 compression springs 5 First pressure roller 5a First pressure roller bearing 6 Cam 7 Cam rotation shaft 8 Bearing guide A 9 Bearing guide B 10 Bearing guide C 11 Foil Film Guide 12 Foil film 12t foil film transfer layer 12u foil film foil layer 13 PCB 13a Recessed portion of substrate 14 Thermally transferred substrate 15 Foil film separating member 16 Halogen heater A 17 Halogen heater B 18 Halogen heater C 19 Heating roller 20 Halogen heater D 100 Foil thermal transfer device

Claims

1. A foil thermal transfer device for thermally transferring a foil film onto a substrate, comprising: a heat roller having an elastic body on its outer periphery; a heat source disposed near the center of the heat roller in the radial direction; a first pressure roller that pinches the substrate and the foil film between the first pressure roller and the heat roller; The heat roller is disposed at a position where it is pinched in the radial direction by the first pressure roller. a second pressure roller; a heat source disposed near the radial center of the second pressure roller; a lifting device that lifts and lowers the first pressure roller; A foil thermal transfer device having:

2. A gap is formed between the heat roller and the second pressure roller before the rollers are pressed together.

2. The foil thermal transfer device according to claim 1.

3. A gap that can be freely opened and closed is provided between the heat roller and the first pressure roller.

3. The foil thermal transfer device according to claim 1 or 2.

4. The first pressure roller and the second pressure roller have substantially the same longitudinal bending strength.

4. The foil thermal transfer device according to claim 3.

5. 4. The foil thermal transfer device according to claim 3, wherein the number of the second pressure rollers is two or more.

6. The first pressure roller has a heat source disposed near the center in the radial direction.

4. The foil thermal transfer device according to claim 3.

7. The heat roller has an elastic body on the outer periphery thereof, the elastic body having a thermal conductivity of 1 to 1.3 W / m·K.

4. The foil thermal transfer device according to claim 3, wherein:

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