JP2021175612A - Thermally expandable sheet and method for producing stereoscopic image - Google Patents

Abstract

To provide a thermally expandable sheet that has an excellent expansion height when a thermally expansion layer is expanded, and a method for producing a stereoscopic image.SOLUTION: A thermally expandable sheet 10 has a base material 11, an anchor layer 12 laminated on one face of the base material 11, and a thermally expansion layer 13 containing a thermally expandable material. When the thermally expansion layer 13 is expanded, the base material 11 is deformed following expansion of the thermally expansion layer 13, where the base material 11 is deformed into an embossed shape.SELECTED DRAWING: Figure 1

Description

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

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 heat absorbed is formed on one surface of the base material sheet. By forming a photothermal conversion layer that converts light into heat on the heat-expandable sheet and irradiating the photothermal conversion layer with light, the heat-expandable layer can be partially or wholly expanded. Further, a method of forming a three-dimensional model (three-dimensional image) on a heat-expandable sheet by changing the shape of the photothermal conversion layer is also known (see, for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 64-28660 Japanese Unexamined Patent Publication No. 2001-150812

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

In order to increase the expansion height, it is conceivable to form a thick thermal expansion layer so that more thermally expandable material is present on the substrate. However, if the heat-expandable layer is formed thick, there is a problem that the thickness of the entire heat-expandable 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 and a method for producing a stereoscopic image when the heat-expandable layer is expanded.

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

In order to achieve the above object, the method for producing a stereoscopic image according to the present invention is:
When a step of forming a heat-expandable layer containing a heat-expandable material having the same thickness as or thicker than the thickness of the base material is formed on one surface of the base material, and the heat-expandable layer is expanded. , The base material is deformed in an embossed shape so as to follow the expansion of the thermal expansion layer and be pulled toward the thermal expansion layer.
It is characterized by that.

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

It is sectional drawing which shows the outline of the heat-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 heat-expandable sheet which concerns on embodiment. It is a figure which shows the outline of the stereoscopic image formation unit which concerns on embodiment. It is a flowchart which shows the stereoscopic image formation process which concerns on embodiment. It is sectional drawing which shows typically the stereoscopic image formation process which concerns on embodiment. (A) It is a figure explaining the part measured 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 the 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 amount of deformation of a base material. (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, a method for producing a heat-expandable sheet and a heat-expandable sheet according to an 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-expandable layer 13, a first ink receiving layer 14, and a second ink receiving layer 15. Further, as will be described in detail later, the heat-expandable sheet 10 is a three-dimensional image forming system 50 whose outline is shown in FIGS. 4 (a) to 4 (c), and is printed and has irregularities (three-dimensional shape). Image) is formed. Further, as will be described in detail later, the heat-expandable sheet 10 of the present embodiment is printed by the stereoscopic image forming system 50, and the base material 11 is shown in FIG. 2 when the heat-expandable layer 13 is expanded. It is characterized in that it deforms following the thermal expansion layer 13.

The base material 11 is a sheet-like member that supports the thermal expansion layer 13 and the like. As the base material 11, paper such as high-quality paper or medium-quality paper, or a commonly used resin sheet-like (including film) material can be appropriately selected and used. The resin sheet contains, 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, and silicone resins. Can be used. Further, in the present embodiment, as will be described in detail later, when the thermal expansion layer 13 is totally or partially expanded by foaming due to heating, the base material 11 is deformed following the expansion of the thermal expansion layer 13. 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 as to be easily deformed by heat. 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 expansion direction of the thermal expansion layer 13 when the thermal expansion layer 13 is foamed and expanded, and the shape is maintained after the deformation. More specifically, when the thermal expansion layer 13 expands, the convex portion 13a shown in FIG. 2 is formed on the thermal expansion layer 13. When the convex portion 13a is formed, the expanding force acts in the direction opposite to that of the base material 11 (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 11a is formed on the surface of the base material 11 so as to protrude 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 the present specification, the shapes of the convex portion 13a of the thermal expansion layer 13, the convex portion 11a and the concave portion 11b of the base material 11 are expressed as embossed.

In one method of so-called embossing, an uneven shape corresponding to the upper and lower molds is formed, and a base material such as paper is sandwiched between the upper and lower molds to form an uneven shape on the base material. On the other hand, in the present embodiment, the base material 11 is deformed by being attracted by the expansion force of the thermal expansion layer 13, so that the shape that matches the shape of the thermal expansion layer after expansion, such as embossing, is detailed. Is not exactly formed on the back surface of the base material 11. For example, when a shape having a complicated planar and / or three-dimensional contour such as having a large number of protrusions or having a plurality of steps is formed on the thermal expansion layer 13, the protrusions or the protrusions on the back surface of the base material 11 Complex contours such as steps do not appear. The shape appearing on the back surface of the base material 11 is a shape in which the contour is abbreviated, and the contours of the details do not exactly match. However, the convex portion 11a and the concave portion 11b formed on the base material 11 are formed directly below the convex portion 13a formed on the thermal expansion layer 13, and the formed regions thereof are substantially 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 as in the present embodiment can be expressed as embossed, which is similar to the shape generated by embossing.

Further, as compared with the case where only the thermal expansion layer 13 expands due to the deformation of the base material 11 in this way, the expansion height is increased by the deformation of the base material 11, and 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 a good expansion height can be obtained for the thermal expansion sheet 10 as a whole. 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 by the amount of deformation of the base material 11.

In this embodiment, not all of the base material 11 under the region where the thermal expansion layer 13 is 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 in an embossed shape. If the degree of foaming and expansion of the thermal expansion layer 13 is low, such as 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 all the base materials 11 under the region in which the thermal expansion layer 13 is expanded are deformed to form an embossed shape, and the thermal expansion layer 13 is raised to a certain height or higher. The base material 11 under the expanded region is deformed into an embossed shape.

The anchor layer 12 is provided on one surface (upper surface shown in FIG. 1) of the base material 11, and a thermal expansion layer 13 is formed on the anchor layer 12. The anchor layer 12 is a layer having good adhesiveness 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 contains at least one resin selected from the group consisting of polyester, acrylic, polyurethane or a copolymer thereof. For example, the resin contained in the anchor layer 12 may contain, for example, only a polyester-based resin, or may contain a polyester-based resin and a polyurethane-based resin. Further, the resin contained in the anchor layer 12 may be modified by a modifying agent. In particular, in the present embodiment, the anchor layer 12 preferably contains a polyester / acrylic / urethane composite resin. Examples of the aqueous dispersion containing the polyester / acrylic / urethane composite resin include, but are not limited to, "WAC-17XC" manufactured by Takamatsu Oil & Fat Co., Ltd.

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

The thermal expansion layer 13 is formed on the anchor layer 12 provided on one surface (upper surface in FIG. 1) of the base material 11. The thermal expansion layer 13 is a layer that expands to a size corresponding to the heating temperature and heating time, and a plurality of thermal expansion materials (thermally expandable microcapsules, microcapsules) are dispersed and arranged in the binder. Further, as will be described in detail later, in the present embodiment, a photothermal conversion layer is formed 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 provided with the photothermal conversion layer. Since 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, foams and expands, only a specific region can be selectively expanded.

As the binder, a thermoplastic resin selected from vinyl acetate-based polymers, acrylic-based polymers and the like is used. Further, the heat-expandable microcapsules are obtained by encapsulating propane, butane, and other low-boiling vaporizable substances in a shell of a thermoplastic resin. The shell is formed from, for example, a thermoplastic resin selected from polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, copolymers thereof, and the like. The average particle size of the heat-expandable microcapsules is about 5 to 50 μm. When the microcapsules are heated above the thermal expansion start temperature, the polymer shell made of resin softens, the low boiling point vaporizable substance contained therein evaporates, and the capsule expands due to the pressure. Although it depends 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 ink used in the printing process, for example, ink of an inkjet printer. The first ink receiving layer 14 is formed by using a general-purpose material depending on the ink used in the printing process. For example, when water-based ink is used, the first ink receiving layer 14 is formed by 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 ink used in the printing process, for example, ink of an inkjet printer. The second ink receiving layer 15 is also formed using a commonly used material, for example, when using an aqueous ink, it is formed using a material selected from porous silica, polyvinyl alcohol (PVA), and the like. Will be done. In particular, when a material that does not easily receive ink such as a plastic film is used as the base material 11 and a photothermal conversion layer is formed on the back side of the base material 11, a second ink receiving layer 15 is provided as shown in FIG. Is preferable. In addition, when the base material 11 is capable of receiving and fixing ink, when the photothermal conversion layer is formed only on the front side of the heat-expandable sheet 10, the material of the base material 11 and the use of the heat-expandable sheet 10 Depending on the situation, the second ink receiving layer 15 can be omitted.

(Manufacturing method of heat-expandable sheet)
Next, a method for manufacturing the heat-expandable sheet 10 will be described with reference to FIGS. 3 (a) to 3 (d).
First, a sheet-like material, for example, a sheet made of polyethylene terephthalate (PET) is prepared as the base material 11. The base material 11 may be in the form of a roll or may be pre-cut. At this time, the material and thickness of the base material 11 are selected so that they can be easily deformed by heat 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 thereof is prepared. Subsequently, 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. 3A.

Next, a binder made of a thermoplastic resin or the like and a heat-expandable material (heat-expandable microcapsules) 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. 3 (b). In addition, in order to obtain the target thickness of the thermal expansion layer 13, the coating liquid may be applied and dried a plurality of times.

Next, a coating liquid for forming the ink receiving layer 14 is prepared using a material that constitutes the first ink receiving layer 14, for example, a material selected from porous silica, PVA, and the like. Subsequently, this coating liquid is applied onto the thermal expansion layer 13 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. 3 (c).

Next, a coating liquid for forming the ink receiving layer 15 is prepared using a material that constitutes the second ink receiving layer 15, for example, a material selected from porous silica, PVA, and the like. Subsequently, this coating liquid is applied onto the other surface of 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 second ink receiving layer 15 as shown in FIG. 3 (d).
When the roll-shaped base material 11 is used, it is cut into a size suitable for the stereoscopic image forming system 50.

The heat-expandable sheet 10 is manufactured by 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 formation system)
Next, the 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. 4C is a plan view of the stereoscopic image forming system 50. , Is a plan view of the stereoscopic image forming system 50 in a state where the top plate 55 is opened. In FIGS. 4 (a) to 4 (c), the X direction is the same as the horizontal direction, the Y direction is the same as the transport direction D in which the sheet is transported, and the Z direction is the same as the vertical direction. be. The X, Y and Z directions are orthogonal to each other.

The control unit 51, the printing unit 52, and the expansion unit 53 are respectively placed in the frame 60 as shown in FIG. 4A. 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 a top plate 55 is passed above the side plates 61. Further, the printing unit 52 and the expansion unit 53 are installed side by side in the X direction on the connecting beam 62 passed between the side plates 61, and the control unit 51 is fixed under the connecting beam 62. The display unit 54 is embedded in the top plate 55 so that the height coincides with the upper 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 unit 52a for carrying in the heat-expandable sheet 10 and a discharge part 52b for discharging the heat-expandable sheet 10. The printing unit 52 prints the designated image on the front surface or the back surface of the heat-expandable sheet 10 carried in from the carry-in unit 52a, and discharges the heat-expandable sheet 10 on which the image is printed from the discharge unit 52b. Further, the printing unit 52 includes color inks (cyan (C), magenta (M), yellow (Y)) for forming the color ink layer 42, which will be described later, and a front side photothermal conversion layer 41 and a back side photothermal conversion layer. A black ink (including carbon black) for forming with 43 is provided. In addition, in order to form a black or gray color in the color ink layer 42, a black color ink that does not contain 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 heat-expandable sheet 10 from the control unit, and based on the color image data, color ink (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 the three colors of CMY or by further using a black color ink that does not contain carbon black.

Further, the printing unit 52 prints the front side photothermal conversion layer 41 using black ink based on the surface foaming data which is the data indicating the portion to be foamed and expanded on the surface of the heat-expandable sheet 10. Similarly, the back side photothermal conversion layer 43 is printed using black ink based on the back surface foaming data which is the data indicating the portion to be expanded and expanded on the back surface of the heat expandable sheet 10. In addition, black ink containing carbon black is an example of a material that converts light into heat. The higher the density of the black ink is 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 expands the heat-expandable sheet 10 by applying heat. As shown in FIG. 4C, the expansion unit 53 includes a carry-in unit 53a for carrying in the heat-expandable sheet 10 and a discharge part 53b for discharging the heat-expandable sheet 10. The expansion unit 53 applies heat to the heat-expandable sheet 10 carried in from the carry-in portion 53a to expand it, and discharges the expanded heat-expandable sheet 10 from the discharge unit 53b. The expansion unit 53 includes an irradiation unit (not shown) inside. The irradiation unit is, for example, a halogen lamp, and has a near-infrared region (wavelength 750 to 1400 nm), a visible light region (wavelength 380 to 750 nm), or a mid-infrared region (wavelength 140 to 4000 nm) with respect to the heat-expandable sheet 10. ) Is irradiated. 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 portion where the black ink is printed than in the portion where the black ink is not printed. Will be done. Therefore, in the thermal expansion layer 13, the region on which the black ink is printed is mainly heated, and as a result, the region on which the black ink is printed expands in the thermal expansion layer 13.

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

(Three-dimensional image formation processing)
Next, referring to the flowchart shown in FIG. 5 and the cross-sectional views of the heat-expandable sheet 10 shown in FIGS. 6 (a) to 6 (d), the stereoscopic image forming system 50 creates a stereoscopic image on the heat-expandable sheet 10. The flow of the processing to be formed will be described.

First, the user prepares the heat-expandable sheet 10 before the stereoscopic image is formed, and designates the color image data, the front surface foaming data, and the back surface foaming data via the display unit 54. Then, the heat-expandable sheet 10 is inserted into the printing unit 52 with its surface facing upward. The printing unit 52 prints a photothermal conversion layer (front side photothermal 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, black ink containing carbon black. The printing unit 52 ejects black ink containing carbon black onto the surface of the heat-expandable sheet 10 according to the designated surface foaming data. As a result, as shown in FIG. 6A, the front photothermal conversion layer 41 is formed on the first ink receiving layer 14. For ease of understanding, the front photothermal conversion layer 41 is shown to be formed on the first ink receiving layer 14, but more accurately, the black ink is 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.

Second, the user inserts the heat-expandable sheet 10 on which the photothermal conversion layer 41 is printed into the expansion unit 53 with its surface facing upward. The expansion unit 53 heats the inserted heat-expandable sheet 10 from the surface. Specifically, the expansion unit 53 irradiates the surface of the heat-expandable sheet 10 with light by the irradiation unit (step S2). The front side photothermal conversion layer 41 printed on the surface of the heat-expandable sheet 10 generates heat by absorbing the irradiated light. As a result, as shown in FIG. 6B, the area 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 under the region on which the photothermal conversion layer 41 is printed rises and deforms upward as shown in FIG. 6B as the thermal expansion layer 13 expands, whereby the base material 11 A dent (recess) is formed on the lower surface of the.

Third, the user inserts the heat-expandable sheet 10 whose surface is 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 heat-expandable sheet 10 (step S3). Specifically, the printing unit 52 ejects cyan C, magenta M, and yellow Y inks onto the surface of the heat-expandable sheet 10 according to the designated color image data. As a result, as shown in FIG. 6C, a color ink layer 42 is formed on the first ink receiving layer 14 and the photothermal conversion layer 41.

Fourth, the user inserts the heat-expandable sheet 10 on which the color ink layer 42 is printed into the expansion unit 53 with its back surface facing upward. The expansion unit 53 heats the inserted heat-expandable sheet 10 from the back surface to dry the color ink layer 42 formed on the front surface of the heat-expandable sheet 10 (step S4). 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 heat-expandable sheet 10 on which the color ink layer 42 is printed into the printing unit 52 with the back surface facing upward. The printing unit 52 prints a photothermal conversion layer (back side photothermal conversion layer 43) on a second ink receiving layer 15 provided on the back surface of the inserted heat-expandable sheet 10 (step S5). The back side photothermal conversion layer 43 is a layer formed of a material that converts light into heat, specifically black ink containing carbon black, similarly to the surface photothermal conversion layer 41 printed on the surface of the heat-expandable sheet 10. Is. The printing unit 52 ejects black ink containing carbon black to the back surface of the heat-expandable sheet 10 according to the designated back surface foaming data. As a result, as shown in FIG. 6C, a 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 photothermal conversion layer 43 is printed into the expansion unit 53 with the back side facing upward. The expansion unit 53 heats the inserted heat-expandable sheet 10 from the back surface. 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 irradiated light. As a result, as shown in FIG. 6D, the area on which the back side photothermal conversion layer 43 of the heat-expandable sheet 10 is printed rises and expands. Further, particularly in the present embodiment, the base material 11 on the region on which the back side photothermal conversion layer 43 is printed is raised and deformed upward as shown in FIG. 6D as the thermal expansion layer 13 expands, resulting in a base. A dent (recess) is formed on the lower surface of the material 11.

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

In FIGS. 5 and 6 (a) to 6 (d), a photothermal conversion layer is formed on the front surface and the back surface of the heat-expandable sheet 10, and the heat-expandable layer 13 is formed from the front surface and the back surface of the heat-expandable 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. Further, the order of these steps can be changed as appropriate.

Next, as the heat-expandable sheet of the present embodiment, an example in which the heat-expandable layers of the heat-expandable sheets having different base materials and thicknesses are expanded and the expansion height and the like are measured will be described. As an example of the heat-expandable sheet of the present 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) are applied on these base materials. , Material) formed a thermal expansion layer. Further, as an example of the conventional heat-expandable sheet, a heat-expandable layer under the same conditions was formed on a paper having a thickness of 190 μm. Photothermal conversion layers having different black densities were formed on the surfaces of these heat-expandable sheets, and the heat-expandable layers were foamed and expanded by irradiating with light under the same conditions. The photothermal conversion layer was formed only on the front side of the heat-expandable sheet, and all the photothermal conversion layers had the same shape.

For each sheet in which the thermal expansion layer is expanded in this way, 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. 7A. The amount of deformation of the concave portion of the base material 11 (the amount of deformation of the base material) was measured. Further, the amount of deformation of the base material was subtracted from the amount of convexity to calculate the amount of pure foaming (expansion) (difference). The relationship between the amount of convexity, the amount of deformation of the base material, and the difference measured in this way and the black density is shown in FIGS. 7 (b), 8 (a), and 8 (b). In addition, in FIG. 7B, FIG. 8A and FIG. 8B, the black density indicates the density of black (K) on the color data when the photothermal conversion layer is printed. K100 is so-called solid black (K100%). K10, K20, K30, K40, K50, K60, K70, K80 and K90 have black (K) densities of 10%, 20%, 30%, 40%, 50% and 60% on the 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, particularly as compared with paper 190 μm. As for PET 100 μm, a higher expansion height was obtained especially at a concentration after K60 as compared with paper 190 μm. At a concentration of K80 or higher with 100 μm of paper and at a concentration of K70 or higher with PET of 50 μm, the thermal expansion layer expanded too strongly and peeled off from the base material.

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

As described above, from FIGS. 7 (b) and 8 (a), the paper 100 μm, PET 50 μm, and PET 100 μm in which the base material is deformed are all 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 clearly 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 base material was deformed, as compared with the paper 190 μm. Therefore, according to the heat-expandable sheet of the present embodiment, it can be said that the expansion height of the heat-expanding layer can be increased by deforming the base material following the expansion of the heat-expanding layer.

Further, from FIGS. 7 (b), 8 (a) and 8 (b), when compared with 100 μm of paper and 100 μm of PET having the same thickness, the amount of convexity, the amount of deformation of the base material, and the difference all exceed 100 μm of paper. rice field. Comparing PET 50 μm and PET 100 μm, which are made of the same material but have different thicknesses, PET 50 μm was larger than the convex amount, the base material deformation amount, and the difference. Further, when comparing the paper 100 μm and the paper 190 μm, the convex amount, the base material deformation amount, and the difference all exceeded the paper 100 μm. Further, for example, when 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 or more than the convex amount of paper 190 μm. rice field. Therefore, if a base material that deforms following the thermal expansion layer is used in this way, the thermal expansion layer can be expanded higher even with the same thickness of the thermal expansion layer. On the other hand, even if the thickness of the thermal expansion layer is reduced, it is possible to obtain the same height as the thermal expansion sheet in which the base material is not deformed.

As described above, in the heat-expandable sheet of the present embodiment, the base material 11 is deformed by following the expansion of the heat-expandable layer 13, so that the thickness of the heat-expandable layer 13 is not increased and the heat-expandable sheet 10 is formed. 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, a release paper, or the like 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 the release paper. Further, the anchor layer 12 can be formed from a material other than those described above.

The figures used in each embodiment are for explaining each embodiment. Therefore, it is not intended to be construed as limiting the thickness of each layer of the heat-expandable sheet to be formed in the ratio as shown in the figure.

Although some embodiments of the present invention have been described, the present invention is included in the invention described in the claims and the equivalent scope thereof. The inventions described in the claims of the original application of the present application are described below.

[Appendix 1]
A heat-expandable sheet in which a heat-expandable layer containing a heat-expandable material is 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 in an embossed shape.
A heat-expandable sheet characterized by that.
[Appendix 2]
An anchor layer is provided between the base material and the thermal expansion layer.
The heat-expandable sheet according to Appendix 1, wherein the heat-expandable sheet is characterized by the above.
[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.
The heat-expandable sheet according to Appendix 1 or 2, characterized in that.
[Appendix 4]
A step of forming a heat-expandable layer containing a heat-expandable material equal to or thicker than the thickness of the base material on one surface of the base material is included.
A method for producing a heat-expandable sheet.
[Appendix 5]
A step of forming an anchor layer on the one surface of the base material is further provided.
The thermal expansion layer is formed on the anchor layer.
The method for producing a heat-expandable sheet according to Appendix 4, wherein the heat-expandable sheet is produced.

10 ... Thermal expansion sheet, 11 ... Substrate, 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 Unit, 52a, 53a ... Carry-in part, 52b, 53b ... Discharge part, 53 ... Expansion unit, 54 ... Display unit, 55 ... Top plate, 60 ... Frame, 61 ...・ Side plate, 62 ・ ・ ・ Connecting beam

In order to achieve the above object, the heat-expandable sheet according to the present invention is
A heat-expandable sheet in which a heat-expandable layer containing a heat-expandable material is formed on one surface of a base material, and a photo-heat conversion layer that converts light into heat is formed on at least one surface.
When the thermal expansion layer is expanded, the base material is deformed so that a recess is formed in the portion where the photothermal conversion layer is formed when viewed from the other surface side of the base material.
It is characterized by that.
Further, in order to achieve the above object, another heat-expandable sheet according to the present invention may be used.
A heat-expandable sheet in which a heat-expandable layer containing a heat-expandable material is formed on one surface of a base material.
When the thermal expansion layer is expanded, the convex amount of the convex portion formed on the one surface side of the thermal expansion sheet due to the expansion of the thermal expansion layer of the base material is after the expansion of the thermal expansion layer. The base material is deformed so as to be larger than the thickness of
It is characterized by that.

In order to achieve the above object, the method for producing a stereoscopic image according to the present invention is:
Forming a thermal expansion layer containing thermally expandable material on one side of the substrate,
A step of forming a photothermal conversion layer that converts light into heat on at least one surface of the base material, and
Including a step of irradiating the photothermal conversion layer with light.
When inflated the thermal expansion layer, wherein the site where the photothermal conversion layer is formed, thereby deformation of the base material so that concave portion is formed when viewed from the other surface side of the substrate,
It is characterized by that.
Further, in order to achieve the above object, another method for producing a stereoscopic image according to the present invention is
A process of creating a heat-expandable sheet by forming a heat-expandable layer containing a heat-expandable material on one surface of a base material, and
A step of forming a photothermal conversion layer that converts light into heat on at least one surface of the heat-expandable sheet, and
Including a step of irradiating the photothermal conversion layer with light.
When the thermal expansion layer is expanded, the base material is a convex portion formed on one surface side of the thermal expansion sheet by expansion of the thermal expansion layer at a portion where the photothermal conversion layer is formed. The base material is deformed so that the convex amount of is larger than the thickness of the thermal expansion layer after expansion.
It is characterized by that.

Claims (6)

A heat-expandable sheet in which a heat-expandable layer containing a heat-expandable material is formed on one surface of a base material.
When the thermal expansion layer is expanded, the base material is embossed so as to be pulled toward the thermal expansion layer by following the expansion of the thermal expansion layer.
A heat-expandable sheet characterized by that. 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 heat-expandable sheet according to claim 1. 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 recess is formed in the photothermal conversion layer. It is formed at the position corresponding to the printed part of
The heat-expandable sheet according to claim 2. When a step of forming a heat-expandable layer containing a heat-expandable material having the same thickness as or thicker than the thickness of the base material is formed on one surface of the base material, and the heat-expandable layer is expanded. , The base material is deformed in an embossed shape so as to follow the expansion of the thermal expansion layer and be pulled toward the thermal expansion layer.
A method for manufacturing a stereoscopic image. A photothermal conversion layer that converts light into heat is printed on the base material or the thermal expansion layer, and the printed portion is irradiated with light to expand the thermal expansion layer.
The method for manufacturing a stereoscopic image according to claim 4, wherein the stereoscopic image is manufactured. A step of forming an anchor layer on the one surface of the base material is further provided.
The thermal expansion layer is formed on the anchor layer.
The method for producing a stereoscopic image according to claim 4 or 5.

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