JP2020073345A - Thermally expandable sheet and method for producing stereoscopic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a heat-expandable sheet and a stereoscopic image having a good expansion height when the heat-expandable layer is expanded. A heat-expandable sheet 10 includes a base material 11, an anchor layer 12 laminated on one surface of the base material 11, and a heat-expandable layer 13 containing a heat-expandable material. When the thermal expansion layer 13 is expanded, the base material 11 is deformed following the expansion of the thermal expansion layer 13, and the base material 11 is deformed in an embossed shape. [Selection diagram] Fig. 1

Description

  The present invention relates to a heat-expandable sheet that expands and expands according to the amount of heat absorbed and a method for producing a stereoscopic image.

  BACKGROUND ART Conventionally, there is known a heat-expandable sheet in which a heat-expandable layer containing a heat-expandable material that foams and expands according to the amount of absorbed heat is formed on one surface of a base sheet. A photothermal conversion layer that converts light into heat is formed on the thermal expansion sheet, and the photothermal conversion layer is irradiated with light, whereby the thermal expansion layer can be partially or wholly expanded. Further, a method of forming a three-dimensional object (three-dimensional image) on the heat-expandable sheet by changing the shape of the light-heat conversion layer is also known (for example, see Patent Documents 1 and 2).

JP 64-28660 A JP 2001-150812 A

  In such a heat-expandable sheet, in order to clearly express the shape of a three-dimensional image with height differences, it is required to increase the expansion height when the thermal expansion layer is foamed and expanded.

  In order to increase the expansion height, it is conceivable to form the thermal expansion layer thick so that the thermal expansion material is more present on the substrate. However, when the thermal expansion layer is formed thick, there is a problem that the thickness of the entire thermal expansion sheet increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat-expandable sheet having a good expansion height when the heat-expansion layer is expanded, and a method for producing a stereoscopic image.

In order to achieve the above object, the heat-expandable sheet according to the present invention,
A heat-expandable sheet having a heat-expansion layer containing a heat-expansion material formed on one surface of a base material,
When the thermal expansion layer is expanded, the base material is deformed into an embossed shape so as to be pulled toward the thermal expansion layer side following the expansion of the thermal expansion layer,
It is characterized by

In order to achieve the above object, the method for producing a stereoscopic image according to the present invention,
When expanding the thermal expansion layer, including the step of forming a thermal expansion layer containing a thermal expansion material having the same thickness as the base material or a thickness greater than the base material on one surface of the base material. , Deforming the substrate into an embossed shape so as to be pulled toward the thermal expansion layer side following the expansion of the thermal expansion layer,
It is characterized by

  According to the present invention, it is possible to provide a heat-expandable sheet having a good expansion height when the heat-expansion layer is expanded, and a method for producing a stereoscopic image.

It is sectional drawing which shows the outline of the thermally expandable sheet which concerns on embodiment. It is sectional drawing which shows typically the example which expanded the thermal expansion layer of the thermal expansion sheet which concerns on embodiment. It is sectional drawing which shows the outline of the manufacturing method of the thermally expandable sheet which concerns on embodiment. It is a figure which shows the outline | summary of the stereo image forming unit which concerns on embodiment. 6 is a flowchart showing a stereoscopic image forming process according to the embodiment. FIG. 6 is a cross-sectional view schematically showing a stereoscopic image forming process according to the embodiment. (A) It is a figure explaining the measured location after expanding the thermal expansion layer of a thermal expansion sheet. (B) It is a graph which shows the relationship between the black density and convex amount of the photothermal conversion layer in each base material. (A) It is a graph which shows the relationship between the black density of the photothermal conversion layer in each base material, and the base material deformation amount. (B) It is a graph which shows the relationship between the black density of the photothermal conversion layer in each base material, and the pure foaming amount (difference).

  Hereinafter, the heat-expandable sheet and the method for manufacturing the heat-expandable sheet according to the embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the heat-expandable sheet 10 includes a base material 11, an anchor layer 12, a heat-expansion layer 13, a first ink receiving layer 14, and a second ink receiving layer 15. Further, as will be described later in detail, the thermally expansive sheet 10 is a three-dimensional image forming system 50 whose outline is shown in FIGS. Image) is formed. Further, as will be described later in detail, when the thermal expansion sheet 10 of the present embodiment is printed by the three-dimensional image forming system 50 and the thermal expansion layer 13 is expanded, the base material 11 becomes as shown in FIG. It is characterized in that it deforms following the thermal expansion layer 13.

  The base material 11 is a sheet-shaped member that supports the thermal expansion layer 13 and the like. As the base material 11, paper such as high-quality paper, medium-quality paper, or a commonly used sheet-shaped (including film) material made of resin can be appropriately selected and used. The resin sheet includes, for example, a resin selected from polyolefin resins such as polyethylene and polypropylene, polyester resins, polyamide resins such as nylon, polyvinyl chloride resins, polyimide resins, silicone resins and the like. Can be used. Further, in the present embodiment, as will be described later in detail, the base material 11 deforms following the expansion of the thermal expansion layer 13 when the thermal expansion layer 13 expands due to foaming wholly or partially by heating. It is characterized by points. Therefore, the base material 11 is required to be easily deformed by heat, and the material used as the base material 11, the thickness of the base material 11 and the like are selected so that the base material 11 is easily heat deformed. For example, the thickness of the base material 11 is preferably the same as the thickness of the thermal expansion layer 13 or thinner than the thermal expansion layer 13.

  The base material 11 is deformed so as to follow the expanding direction of the thermal expansion layer 13 when the thermal expansion layer 13 is foamed and expanded, and maintains its shape after the deformation. More specifically, when the thermal expansion layer 13 expands, the thermal expansion layer 13 is formed with the convex portion 13a shown in FIG. When the convex portion 13a is formed, the expanding force acts in the direction opposite to the base material 11 (the upper side shown in FIG. 2). The base material 11 is deformed by being attracted by this expanding force. Then, as shown in FIG. 2, a convex portion 11 a is formed on the surface of the base material 11 so as to project from the surrounding region. Further, on the back surface of the base material 11, a concave portion 11b corresponding to the shape of the convex portion 11a formed on the front surface is formed. In this specification, the shapes of the protrusions 13a of the thermal expansion layer 13, the protrusions 11a and the recesses 11b of the base material 11 are expressed as embossed.

  In one method of so-called embossing, uneven shapes corresponding to the upper and lower molds are formed, a base material such as paper is sandwiched in the upper and lower molds, and the uneven shape is formed on the base material. On the other hand, in the present embodiment, the base material 11 is deformed by being pulled by the force of expansion of the thermal expansion layer 13, and thus the shape that matches the shape of the thermal expansion layer after expansion, such as embossing, is detailed. It is not exactly formed on the back surface of the substrate 11. For example, when the thermal expansion layer 13 has a shape having a complex planar and / or three-dimensional contour, such as a plurality of protrusions or a plurality of steps, the protrusions or the protrusions may be formed on the back surface of the substrate 11. No complicated contours such as steps appear. The shape that appears on the back surface of the base material 11 is a shape in which the contour is abbreviated, and the contours of details do not exactly match. However, the convex portion 11a and the concave portion 11b formed on the base material 11 are formed immediately below the convex portion 13a formed on the thermal expansion layer 13, and the formed regions are almost the same. Further, the shape of the convex portion 11a is a shape in which the convex portion 13a is substantially reduced, and the shape of the concave portion 11b is also the same. Therefore, the shape of the base material 11 like this embodiment can be expressed as an embossed shape, which is similar to the shape generated by embossing.

  Further, the deformation of the base material 11 in this way increases the expansion height by the amount of deformation of the base material 11 as compared with the case where only the thermal expansion layer 13 expands, and thus the effect of increasing the overall expansion height. There is. That is, when viewed from the entire thermal expansion sheet 10, the height after expansion is the expansion height of the thermal expansion layer 13 itself and the deformed height of the base material 11. Therefore, even if the expansion height of the thermal expansion layer 13 itself is reduced, the expansion height can be supplemented by the base material 11, and the thermal expansion sheet 10 as a whole can obtain a good expansion height. Further, when the same expansion height is obtained, the thermal expansion layer 13 can be formed thinner than the conventional configuration in which the base material is not deformed because the base material 11 is deformed.

  In addition, in this embodiment, not all the base material 11 below the area | region where the thermal expansion layer 13 expanded is deformed. When the thermal expansion layer 13 is expanded to a certain thickness or more, the back surface of the base material 11 is deformed into an embossed shape. When the degree of foaming or expansion of the thermal expansion layer 13 is low, for example, by reducing the concentration of the photothermal conversion layer, the base material 11 may not be deformed. Therefore, in the present embodiment, it is not intended that the base material 11 under the region where the thermal expansion layer 13 is expanded is entirely deformed and becomes an embossed shape, and the thermal expansion layer 13 is set to a certain height or more. The base material 11 under the expanded region is deformed into an embossed shape.

  The anchor layer 12 is provided on one surface (the upper surface shown in FIG. 1) of the base material 11, and the thermal expansion layer 13 is formed on the anchor layer 12. The anchor layer 12 is a layer having good adhesion to the base material 11 and the thermal expansion layer 13, and suppresses peeling from the base material 11 when the thermal expansion layer 13 expands. The anchor layer 12 includes at least one resin selected from the group consisting of polyester, acrylic, polyurethane, or a copolymer of any of these. For example, the resin contained in the anchor layer 12 may include, for example, only a polyester resin, or may include a polyester resin and a polyurethane resin. The resin contained in the anchor layer 12 may be modified with a modifier. In particular, in this embodiment, the anchor layer 12 preferably contains a polyester / acrylic / urethane composite resin. Although not limited to this, examples of the aqueous dispersion containing a polyester / acrylic / urethane composite resin include “WAC-17XC” manufactured by Takamatsu Yushi Co., Ltd. and the like.

  In the present embodiment, the base material 11 is deformed following the expansion of the thermal expansion layer 13 as described above, so that the base material 11 and the thermal expansion layer 13 are well adhered to each other so that peeling does not occur. It is preferable that the anchor layer 12 is provided between the both. The anchor layer 12 may be omitted if the base material 11 and the thermal expansion layer 13 are well bonded and the expansion of the thermal expansion layer 13 does not cause peeling.

  The thermal expansion layer 13 is formed on the anchor layer 12 provided on one surface (the upper surface in FIG. 1) of the base material 11. The thermal expansion layer 13 is a layer that expands to a size according to the heating temperature and the heating time, and a plurality of thermally expandable materials (thermally expandable microcapsules, microcapsules) are dispersed and arranged in the binder. Further, as described in detail later, in the present embodiment, the photothermal conversion layer is provided on the first ink receiving layer 14 provided on the upper surface (front surface) of the base material 11 and / or on the lower surface (back surface) of the base material 11. Is formed and irradiated with light to generate heat in the region where the photothermal conversion layer is provided. The thermal expansion layer 13 absorbs the heat generated in the photothermal conversion layer on the front surface and / or the back surface of the thermal expansion sheet 10 to foam and expand, so that only a specific region can be selectively expanded.

  As the binder, a thermoplastic resin selected from vinyl acetate-based polymers, acrylic polymers and the like is used. The heat-expandable microcapsules are obtained by encapsulating propane, butane, and other low boiling point vaporizable substances in the shell of a thermoplastic resin. The shell is formed of a thermoplastic resin selected from, for example, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof. The average particle size of the heat-expandable microcapsules is about 5 to 50 μm. When the microcapsules are heated above the thermal expansion starting temperature, the polymer shell made of resin is softened, the low boiling point volatile substance contained therein is vaporized, and the pressure causes the capsules to expand. Although depending on the characteristics of the microcapsules used, the microcapsules expand to about 5 times the particle size before expansion.

  The first ink receiving layer 14 is formed on the thermal expansion layer 13 formed on one surface of the base material 11. The first ink receiving layer 14 is a layer that receives and fixes the ink used in the printing process, for example, the ink of an inkjet printer. The first ink receiving layer 14 is formed by using a widely used material according to the ink used in the printing process. For example, when using a water-based ink, the first ink receiving layer 14 is formed using a material selected from porous silica, polyvinyl alcohol (PVA), and the like.

  The second ink receiving layer 15 is formed on the other surface of the base material 11. Like the first ink receiving layer 14, the second ink receiving layer 15 is a layer that receives and fixes the ink used in the printing process, for example, the ink of an inkjet printer. The second ink receiving layer 15 is also formed by using a commonly used material. For example, when using an aqueous ink, it is formed by using a material selected from porous silica, polyvinyl alcohol (PVA), and the like. To be done. In particular, when a material such as a plastic film that does not easily receive ink is used as the base material 11 and a photothermal conversion layer is further formed on the back side of the base material 11, the second ink receiving layer 15 is provided as shown in FIG. Preferably. In addition, when the base material 11 can receive and fix the ink, when the light-heat conversion layer is formed only on the front side of the thermal expansion sheet 10, the material of the base material 11, the use of the thermal expansion sheet 10 Accordingly, the second ink receiving layer 15 can be omitted.

(Method of manufacturing heat-expandable sheet)
Next, a method for manufacturing the thermally expandable sheet 10 will be described with reference to FIGS. 3 (a) to 3 (d).
First, as the base material 11, a sheet-shaped material, for example, a sheet made of polyethylene terephthalate (PET) is prepared. The base material 11 may be roll-shaped or may be cut beforehand. At this time, the material and the thickness of the base material 11 are selected such that they are easily thermally deformed so that they can be deformed following the expansion of the thermal expansion layer 13. For example, the thickness of the base material 11 is preferably the same as the thickness of the thermal expansion layer 13 or thinner than the thermal expansion layer 13.

  Next, in order to form the anchor layer 12, a coating liquid containing at least one resin selected from the group consisting of polyester, acrylic, polyurethane, or a copolymer of any of these is prepared. Then, the coating liquid is applied onto the base material 11 using a known coating device such as a bar coater, a roller coater, or a spray coater. Subsequently, the coating film is dried to form the anchor layer 12 as shown in FIG.

  Next, a binder made of a thermoplastic resin or the like and a heat-expandable material (heat-expandable microcapsule) are mixed to prepare a coating liquid for forming the heat-expandable layer 13. Subsequently, the coating liquid is applied onto the anchor layer 12 using a known coating device such as a bar coater, a roller coater, or a spray coater. Subsequently, the coating film is dried to form the thermal expansion layer 13 as shown in FIG. In addition, in order to obtain the target thickness of the thermal expansion layer 13, the coating liquid may be applied and dried plural times.

  Next, a coating liquid for forming the ink receiving layer 14 is prepared using a material forming the first ink receiving layer 14, for example, a material selected from porous silica and PVA. Subsequently, the coating solution is applied onto the thermal expansion layer 13 by using a known coating device such as a bar coater, a roller coater, or a spray coater. Subsequently, the coating film is dried to form the first ink receiving layer 14 as shown in FIG.

Next, a coating liquid for forming the ink receiving layer 15 is prepared using a material forming the second ink receiving layer 15, such as a material selected from porous silica and PVA. Subsequently, the coating liquid is applied to the other surface of the base material 11 by using a known coating device such as a bar coater, a roller coater, and a spray coater. Subsequently, the coating film is dried to form the second ink receiving layer 15 as shown in FIG.
When the roll-shaped substrate 11 is used, it is cut into a size suitable for the three-dimensional image forming system 50.

The thermally expandable sheet 10 is manufactured through the above steps.
The step of forming the second ink receiving layer 15 may be performed before the step of forming the anchor layer 12.

(3D image forming system)
Next, a stereoscopic image forming system 50 that forms a stereoscopic image on the heat-expandable sheet 10 of the present embodiment will be described. As shown in FIGS. 4A to 4C, the stereoscopic image forming system 50 includes a control unit 51, a printing unit 52, an expansion unit 53, a display unit 54, a top plate 55, and a frame 60. And FIG. 4A is a front view of the stereoscopic image forming system 50, FIG. 4B is a plan view of the stereoscopic image forming system 50 with the top plate 55 closed, and FIG. 3 is a plan view of the stereoscopic image forming system 50 with a top plate 55 opened. FIG. 4A to 4C, the X direction is the same as the horizontal direction, the Y direction is the same as the conveyance direction D in which the sheet is conveyed, and the Z direction is the same as the vertical direction. is there. The X direction, the Y direction, and the Z direction are orthogonal to each other.

  The control unit 51, the printing unit 52, and the expansion unit 53 are placed in the frame 60 as shown in FIG. Specifically, the frame 60 includes a pair of substantially rectangular side plates 61 and a connecting beam 62 provided between the side plates 61, and the top plate 55 is provided above the side plates 61. The printing unit 52 and the expansion unit 53 are arranged side by side in the X direction on the connection beam 62 passed between the side plates 61, and the control unit 51 is fixed below the connection beam 62. The display unit 54 is embedded in the top plate 55 so that the height of the display unit 54 is the same as the top surface of the top plate 55.

  The control unit 51 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the printing unit 52, the expansion unit 53, and the display unit 54.

  The printing unit 52 is an inkjet printing device. As shown in FIG. 4C, the printing unit 52 includes a carry-in section 52a for carrying in the heat-expandable sheet 10 and a discharge section 52b for discharging the heat-expandable sheet 10. The printing unit 52 prints the instructed image on the front surface or the back surface of the heat-expandable sheet 10 carried in from the carry-in section 52a, and discharges the heat-expandable sheet 10 on which the image is printed from the discharge section 52b. In the printing unit 52, color inks (cyan (C), magenta (M), yellow (Y)) for forming a color ink layer 42, which will be described later, a front side photothermal conversion layer 41 and a back side photothermal conversion layer. And black ink (including carbon black) for forming 43. In addition, in order to form a black or gray color in the color ink layer 42, a black color ink containing no carbon black may be further provided as the color ink.

  The printing unit 52 acquires color image data indicating a color image (color ink layer 42) to be printed on the surface of the thermal expansion sheet 10 from the control unit, and based on the color image data, color inks (cyan, magenta, yellow). ) Is used to print a color image (color ink layer 42). The black or gray color of the color ink layer 42 is formed by mixing three colors of CMY or by further using a black color ink not containing carbon black.

  In addition, the printing unit 52 prints the front-side light-heat conversion layer 41 using black ink based on the surface foaming data that is the data indicating the portion to be foamed and expanded on the surface of the thermal expansion sheet 10. Similarly, the backside light-heat conversion layer 43 is printed using black ink based on the backside foaming data, which is the data indicating the portion to be foamed and expanded on the backside of the thermal expansion sheet 10. Black ink containing carbon black is an example of a material that converts light into heat. The higher the density of the black ink formed, the higher the expansion height of the thermal expansion layer. Therefore, the density of the black ink is determined so as to correspond to the target height.

  The expansion unit 53 is an expansion device that applies heat to the thermally expandable sheet 10 to expand it. As shown in FIG. 4C, the expansion unit 53 includes a carry-in portion 53a for carrying in the heat-expandable sheet 10 and a discharge portion 53b for discharging the heat-expandable sheet 10. The expansion unit 53 applies heat to the thermally expandable sheet 10 carried in from the carry-in section 53a to expand it, and discharges the expanded thermally expandable sheet 10 from the discharge section 53b. The expansion unit 53 includes an irradiation unit (not shown) inside. The irradiation unit is, for example, a halogen lamp, and with respect to the heat-expandable sheet 10, a near infrared region (wavelength 750 to 1400 nm), a visible light region (wavelength 380 to 750 nm) or a mid infrared region (wavelength 1400 to 4000 nm). ). When the heat-expandable sheet 10 on which the black ink containing carbon black is printed is irradiated with light, the light is converted into heat more efficiently in the part printed with the black ink than in the part not printed with black ink. To be done. Therefore, in the thermal expansion layer 13, the area where the black ink is printed is mainly heated, and as a result, in the thermal expansion layer 13, the area where the black ink is printed expands.

  The display unit 54 includes a touch panel or the like. The display unit 54 displays an image (a star shown in FIG. 4B) printed on the thermal expansion sheet 10 by the printing unit 52, as shown in FIG. 4B, for example. Further, the display unit 54 displays an operation guide and the like, and the user can operate the stereoscopic image forming system 50 by touching the display unit 54.

(Stereoscopic image forming process)
Next, referring to the flowchart shown in FIG. 5 and the sectional views of the heat-expandable sheet 10 shown in FIGS. 6A to 6D, a stereoscopic image is formed on the heat-expandable sheet 10 by the stereoscopic image forming system 50. The flow of the forming process will be described.

  First, the user prepares the thermally expansive sheet 10 before the stereoscopic image is formed, and specifies the color image data, the front surface foaming data, and the rear surface foaming data via the display unit 54. Then, the thermally expandable sheet 10 is inserted into the printing unit 52 with its surface facing upward. The printing unit 52 prints the light-heat conversion layer (front-side light-heat conversion layer 41) on the surface of the inserted heat-expandable sheet 10 (step S1). The front-side photothermal conversion layer 41 is a layer formed of a material that converts light into heat, specifically, a black ink containing carbon black. The printing unit 52 ejects black ink containing carbon black onto the surface of the thermal expansion sheet 10 according to the designated surface foaming data. As a result, as shown in FIG. 6A, the front side photothermal conversion layer 41 is formed on the first ink receiving layer 14. For easier understanding, the front-side photothermal conversion layer 41 is illustrated as being formed on the first ink receiving layer 14, but more accurately, the black ink is more accurately used for the first ink receiving layer 14. Since it is received inside, the front side photothermal conversion layer 41 is formed in the first ink receiving layer 14.

  Secondly, the user inserts the heat-expandable sheet 10 on which the light-heat conversion layer 41 is printed into the expansion unit 53 with its surface facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 10 from the surface. More specifically, the expansion unit 53 causes the irradiation unit to irradiate the surface of the heat-expandable sheet 10 with light (step S2). The front-side photothermal conversion layer 41 printed on the surface of the heat-expandable sheet 10 absorbs the emitted light to generate heat. As a result, as shown in FIG. 6B, the region of the heat-expandable sheet 10 on which the photothermal conversion layer 41 is printed rises and expands. In particular, in the present embodiment, the base material 11 below the region where the photothermal conversion layer 41 is printed is bulged upward and deformed as the thermal expansion layer 13 expands, whereby the base material 11 is deformed. A depression (recess) is formed on the lower surface of the.

  Thirdly, the user inserts the heat-expandable sheet 10 whose surface has been heated and expanded into the printing unit 52 with its surface facing upward. The printing unit 52 prints a color image (color ink layer 42) on the surface of the inserted thermally expansive sheet 10 (step S3). Specifically, the printing unit 52 ejects cyan C, magenta M, and yellow Y inks on the surface of the thermally expansive sheet 10 according to the designated color image data. As a result, as shown in FIG. 6C, the color ink layer 42 is formed on the first ink receiving layer 14 and the photothermal conversion layer 41.

  Fourthly, the user inserts the thermally expansive sheet 10 on which the color ink layer 42 is printed into the expansive unit 53 with the back surface thereof facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 10 from the back surface, and dries the color ink layer 42 formed on the surface of the thermal expansion sheet 10 (step S4). More specifically, the expansion unit 53 irradiates the back surface of the heat-expandable sheet 10 with light by the irradiation unit to heat the color ink layer 42 and volatilize the solvent contained in the color ink layer 42.

  Fifth, the user inserts the thermally expansive sheet 10 on which the color ink layer 42 is printed into the printing unit 52 with the back surface thereof facing upward. The printing unit 52 prints the photothermal conversion layer (backside photothermal conversion layer 43) on the second ink receiving layer 15 provided on the back surface of the inserted thermal expansion sheet 10 (step S5). The backside light-heat conversion layer 43 is a layer formed of a material that converts light into heat, specifically, a black ink containing carbon black, like the surface light-heat conversion layer 41 printed on the surface of the heat-expandable sheet 10. Is. The printing unit 52 ejects black ink containing carbon black onto the back surface of the thermally expansive sheet 10 according to the specified back surface foaming data. As a result, as shown in FIG. 6C, the photothermal conversion layer 43 is formed on the back surface of the base material 11.

  Sixth, the user inserts the heat-expandable sheet 10 on which the back-side light-heat conversion layer 43 is printed into the expansion unit 53 with the back surface thereof facing upward. The expansion unit 53 heats the inserted thermally expandable sheet 10 from the back surface. More specifically, the expansion unit 53 irradiates the back surface of the heat-expandable sheet 10 with light by an irradiation unit (not shown) (step S6). The photothermal conversion layer 43 printed on the back surface of the heat-expandable sheet 10 generates heat by absorbing the applied light. As a result, as shown in FIG. 6D, the region of the thermally expansive sheet 10 on which the back-side photothermal conversion layer 43 is printed rises and expands. In addition, particularly in the present embodiment, the base material 11 above the region where the back-side photothermal conversion layer 43 is printed is bulged upward and deformed as the thermal expansion layer 13 expands, as shown in FIG. A depression (recess) is formed on the lower surface of the material 11.

  A three-dimensional image is formed on the heat-expandable sheet 10 by the above procedure.

  In addition, in FIG. 5 and FIG. 6A to FIG. 6D, the photothermal conversion layer is formed on the front surface and the back surface of the thermal expansion sheet 10, and the thermal expansion layer 13 is formed from the front surface and the back surface of the thermal expansion sheet 10. Although the configuration of foaming and expanding is given as an example, the photothermal conversion layer may be formed only on the front surface or only the back surface. When the photothermal conversion layer is formed only on the front surface, steps S1 to S4 shown in FIG. 5 are performed, and when the photothermal conversion layer is formed only on the back surface, steps S3 to S6 shown in FIG. 6 are performed. Also, the order of these steps can be changed appropriately.

  Next, as the heat-expandable sheet of the present embodiment, an example in which the base material and the heat-expandable layers of the heat-expandable sheets having different thicknesses are expanded and the expansion height and the like are measured will be described. As an example of the heat-expandable sheet of this embodiment, 100 μm-thick paper, 100 μm-thick PET film, and 50 μm-thick PET film are prepared as base materials, and the same conditions (thickness) , Material) thermal expansion layer was formed. Further, as an example of a conventional heat-expandable sheet, a heat-expansion layer under the same conditions was formed on a paper having a thickness of 190 μm. Light-heat conversion layers having different black concentrations were formed on the surface of these heat-expandable sheets, and light was irradiated under the same conditions to foam and expand the heat-expansion layers. The photothermal conversion layer was formed only on the front side of the heat-expandable sheet, and the photothermal conversion layers had the same shape.

  For each sheet obtained by expanding the thermal expansion layer in this manner, the expansion height (convex amount) of the thermal expansion layer from the upper surface of the thermal expansion layer and the height corresponding to the upper surface of the base material 11 shown in FIG. The amount of deformation of the concave portion of the base material 11 (base material deformation amount) was measured. In addition, the amount of substrate deformation was subtracted from the amount of protrusion to calculate the pure amount of foaming (expansion) (difference). The relationship between the amount of convexity, the amount of deformation of the base material, the difference, and the black density thus measured is shown in FIGS. 7B, 8A, and 8B. 7 (b), 8 (a), and 8 (b), the black density indicates the density of black (K) on the color data when printing the photothermal conversion layer. K100 is so-called solid black (K100%). K10, K20, K30, K40, K50, K60, K70, K80, and K90 have a black (K) density of 10%, 20%, 30%, 40%, 50%, and 60% on color data, respectively. , 70%, 80% and 90%.

  First, as shown in FIG. 7B, it can be seen that a higher expansion height (convex amount) was obtained for PET 50 μm and paper 100 μm, especially compared with paper 190 μm. Also for PET 100 μm, a high expansion height was obtained at a density of K60 or later, as compared with 190 μm of paper. It should be noted that the thermal expansion layer was too strongly expanded at a density of K80 or higher for 100 μm paper and at a density of K70 or higher for PET 50 μm, and was peeled from the substrate.

  Next, as shown in FIG. 8A, with respect to the paper of 190 μm, almost no deformation of the base material was observed at any black density. On the other hand, regarding 100 μm of paper, 50 μm of PET, and 100 μm of PET, deformation was observed in the substrate. In particular, for PET 50 μm and paper 100 μm, the deformation of the substrate was observed after K30, and for PET 100 μm, a relatively flat amount of substrate deformation was observed at a concentration of K60 or higher.

  As described above, from FIGS. 7B and 8A, regarding the paper 100 μm, PET 50 μm, and PET 100 μm in which the base material is deformed, as compared with the paper 190 μm in which the base material is not deformed, The amount of deformation was added, and the amount of convexity obviously increased. Further, as shown in FIG. 8B, the pure foaming amount (difference) also tended to be higher in the paper 100 μm, PET 50 μm, and PET 100 μm in which the deformation of the substrate was observed, compared with the paper 190 μm. Therefore, according to the thermally expandable sheet of the present embodiment, it can be said that it is possible to increase the expansion height of the thermal expansion layer by deforming the base material while following the expansion of the thermal expansion layer.

  Further, comparing FIGS. 7B, 8A, and 8B with paper 100 μm having the same thickness and PET 100 μm, paper 100 μm is higher in all of the convex amount, substrate deformation amount, and difference. It was Comparing PET 50 μm and PET 100 μm having the same material with different thicknesses, PET 50 μm exceeded the projection amount, the substrate deformation amount, and the difference. Further, when the paper 100 μm and the paper 190 μm are compared, the projection amount, the base material deformation amount, and the difference are all over the paper 100 μm. Further, for example, comparing the convex amount of PET 50 μm and paper 100 μm with the convex amount of paper 190 μm, the convex amount of PET 50 μm and paper 100 μm is twice as large as the convex amount of paper 190 μm or more. It was Therefore, by using the base material that deforms following the thermal expansion layer in this way, the thermal expansion layer can be expanded to a higher extent even with the same thermal expansion layer thickness. On the other hand, even if the thickness of the thermal expansion layer is reduced, it is possible to obtain the same height as that of the thermal expansion sheet in which the base material does not deform.

  As described above, in the heat-expandable sheet of the present embodiment, the base material 11 is deformed following the expansion of the heat-expansion layer 13 to increase the thickness of the heat-expansion layer 13 without increasing the thickness of the heat-expansion sheet 10. The inflatable height can be increased. Further, when the same expansion height can be obtained, the thickness of the thermal expansion layer 13 can be reduced, and the thickness of the thermal expansion sheet 10 can also be reduced.

The present invention is not limited to the above-described embodiment, and various modifications and applications are possible.
When the heat-expandable sheet 10 is used by being attached to a container or the like, an adhesive, release paper, etc. may be provided on the back surface of the base material 11. In this case, the second ink receiving layer 15 may be formed on release paper. In addition, the anchor layer 12 can be formed of a material other than the above.

  It should be noted that the drawings used in the respective embodiments are for explaining the respective embodiments. Therefore, the thickness of each layer of the heat-expandable sheet is not intended to be limitedly interpreted as being formed in the ratio as shown in the drawing.

  Although some embodiments of the present invention have been described, the present invention is included in the invention described in the claims and the scope of equivalents thereof. The inventions described in the initial claims of the present application will be additionally described below.

[Appendix 1]
A heat-expandable sheet having a heat-expansion layer containing a heat-expansion material formed on one surface of a base material,
When the thermal expansion layer is expanded, the base material is deformed following the expansion of the thermal expansion layer, and the base material is deformed into an embossed shape,
A heat-expandable sheet characterized by the above.
[Appendix 2]
An anchor layer is provided between the base material and the thermal expansion layer,
The heat-expandable sheet according to Appendix 1, which is characterized in that
[Appendix 3]
The thickness of the base material is the same as the thickness of the thermal expansion layer, or is formed thinner than the thermal expansion layer,
3. The heat-expandable sheet according to appendix 1 or 2, characterized in that
[Appendix 4]
On one surface of the base material, including the step of forming a thermal expansion layer containing a thermal expansion material that is the same as the thickness of the base material or is thicker than the thickness of the base material,
A method for producing a heat-expandable sheet, comprising:
[Appendix 5]
Further comprising a step of forming an anchor layer on the one surface of the substrate,
Forming the thermal expansion layer on the anchor layer;
5. The method for producing a heat-expandable sheet as described in appendix 4, wherein.

10 ... Thermal expansion sheet, 11 ... Base material, 12 ... Anchor layer, 13 ... Thermal expansion layer, 14 ... First ink receiving layer, 15 ... Second ink Receiving layer, 41 ... Front side photothermal conversion layer, 42 ... Color ink layer, 43 ... Back side photothermal conversion layer, 50 ... Stereoscopic image forming system, 51 ... Control unit, 52 ... Printing Units, 52a, 53a ... Carry-in section, 52b, 53b ... Discharge section, 53 ... Expansion unit, 54 ... Display unit, 55 ... Top plate, 60 ... Frame, 61 ...・ Side plate, 62 ... Connection beam

In order to achieve the above object, the heat-expandable sheet according to the present invention,
A heat-expandable sheet having a heat-expansion layer containing a heat-expansion material formed on a substrate,
When the thermal expansion layer is expanded, the base material is pulled and deformed by the force of expansion of the thermal expansion layer,
It is characterized by

In order to achieve the above object, the method for producing a stereoscopic image according to the present invention,
Forming a thermal expansion layer containing a thermal expansion material on the substrate,
Forming a photothermal conversion layer for converting light into heat on the base material or the thermal expansion layer;
Irradiating the photothermal conversion layer with light,
Including,
When the thermal expansion layer is expanded, the base material is pulled and deformed by the force of expansion of the thermal expansion layer,
It is characterized by

Claims (6)

A heat-expandable sheet having a heat-expansion layer containing a heat-expansion material formed on one surface of a base material,
When the thermal expansion layer is expanded, the base material is deformed into an embossed shape so as to be pulled toward the thermal expansion layer side following the expansion of the thermal expansion layer,
A heat-expandable sheet characterized by the above. When the base material is deformed following the thermal expansion layer, it is deformed so that a recess is formed on the other surface of the base material,
The thermally expandable sheet according to claim 1, wherein When a photothermal conversion layer that converts light into heat is printed on the base material or the thermal expansion layer and the thermal expansion layer is expanded by irradiating the printed portion with light, the concave portion is the photothermal conversion layer. Is formed at the position corresponding to the print area of
The thermally expansive sheet according to claim 2, wherein When expanding the thermal expansion layer, including the step of forming a thermal expansion layer containing a thermal expansion material having the same thickness as the base material or a thickness greater than the base material on one surface of the base material. , Deforming the substrate into an embossed shape so as to be pulled toward the thermal expansion layer side following the expansion of the thermal expansion layer,
A method for producing a stereoscopic image, which is characterized by the above. A photothermal conversion layer that converts light into heat is printed on the base material or the thermal expansion layer, and the thermal expansion layer is expanded by irradiating the printed portion with light.
The method for producing a stereoscopic image according to claim 4, wherein. Further comprising a step of forming an anchor layer on the one surface of the substrate,
Forming the thermal expansion layer on the anchor layer;
The method for producing a stereoscopic image according to claim 4 or 5, characterized in that.

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