Patent Application
20180272781
This application claims the benefit of Japanese Patent Application No. 2017-059401, filed on Mar. 24, 2017, Japanese Patent Application No. 2018-029583, filed on Feb. 22, 2018, and Japanese Patent Application No. 2018-041457, filed on Mar. 8, 2018, the entire disclosures of which is incorporated by reference herein.
This application relates generally to an ink, and more particularly to an ink for forming a photothermal conversion layer for causing a part or all of a thermal expansion sheet, which foams and swells in accordance with the amount of absorbed heat, to swell, a thermal expansion sheet using the ink, a manufacturing method for a shaped object, a printing apparatus, and a printing method.
In the related art, there are thermal expansion sheets obtained by forming a thermal expansion layer including a thermally expandable material on one surface of a base sheet. This thermally expandable material foams and swells in accordance with the amount of absorbed heat. By forming a photothermal conversion layer that converts light to heat on the thermal expansion sheet and irradiating the photothermal conversion layer with light, part or all the thermal expansion layer can be made to swell. Additionally, methods are known in the related art for forming a pseudo-three-dimensional shaped object (pseudo-three-dimensional image) on a thermal expansion sheet by changing the shape of the photothermal conversion layer (see, for example, Unexamined Japanese Patent Application Kokai Publication No. S64-28660 and Unexamined Japanese Patent Application Kokai Publication No. 2001-150812).
Photothermal conversion layers are typically formed using black ink containing carbon. However, in some cases, the black ink used to print the photothermal conversion layer affects the color of the resulting pseudo-three-dimensional image. For example, when the photothermal conversion layer is formed on the surface of a thermal expansion sheet and a color image is printed on the photothermal conversion layer using color ink, the color image may be dulled by the black ink of the photothermal conversion layer. Moreover, the color of the photothermal conversion layer appears as-is in the region of the surface of the thermal expansion sheet where the photothermal conversion layer is to be formed and swelling is intended occur.
Therefore, in order to reduce the effects of the photothermal conversion layer on the color of the pseudo-three-dimensional image (shaped object), suppression of color of the photothermal conversion layer is desired. In particular, there is a need for an ink, a thermal expansion sheet using the ink, a manufacturing method for a shaped object, a printing apparatus, and a printing method whereby a colorless transparent photothermal conversion layer having suppressed color can be formed.
In light of the state of the art, an object of this application is to provide an ink for forming a colorless transparent photothermal conversion layer, and a thermal expansion sheet, a manufacturing method for a shaped object, a printing apparatus, and a printing method using this ink.
An aspect of the present disclosure is an ink for forming a photothermal conversion layer used for causing expansion of at least a portion of a thermal expansion layer of a thermal expansion sheet. The ink includes (i) an inorganic infrared absorbing agent having a higher absorptivity in at least one region of an infrared light spectrum than in a visible light spectrum, and (ii) a base that is transparent to visible light.
Another aspect of the present disclosure is a manufacturing method for manufacturing a shaped object by using a photothermal conversion layer for causing expansion of at least a portion of a thermal expansion layer of a thermal expansion sheet. The manufacturing method includes forming a photothermal conversion layer using an ink on at least one surface of the thermal expansion sheet. The ink includes (i) an inorganic infrared absorbing agent having a higher absorptivity in at least one region of an infrared light spectrum than in a visible light spectrum, and (ii) a base that is transparent to visible light.
Another aspect of the present disclosure is a thermal expansion sheet includes: a thermal expansion layer that swells due to heat, and a photothermal conversion layer for causing expansion of the thermal expansion layer. The photothermal conversion layer includes an inorganic infrared absorbing agent having a higher absorptivity in at least one region of an infrared light spectrum than in a visible light spectrum. The photothermal conversion layer is transparent to visible light.
Another aspect of the present disclosure is a printing apparatus for printing a photothermal conversion layer used for causing expansion of at least a portion of a thermal expansion layer of a thermal expansion sheet. The printing apparatus uses an ink to print the photothermal conversion layer on at least one surface of the thermal expansion sheet. The ink includes (i) an inorganic infrared absorbing agent having a higher absorptivity in at least one region of an infrared light spectrum than in a visible light spectrum, and (ii) a base that is transparent to visible light.
Another aspect of the present disclosure is a printing method for printing a photothermal conversion layer used for causing expansion of at least a portion of a thermal expansion layer of a thermal expansion sheet. The printing method includes using an ink to print a photothermal conversion layer on at least one surface of the thermal expansion sheet. The ink includes (i) an inorganic infrared absorbing agent having a higher absorptivity in at least one region of an infrared light spectrum than in a visible light spectrum, and (ii) a base that is transparent to visible light.
A more complete understanding of this application can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:
Hereinafter, a description is given of an ink, and a thermal expansion sheet, a manufacturing method for a shaped object, a printing apparatus, and a printing method using the ink according to embodiments of this application with reference to the drawings. An ink 10 as described below is an ink (referred to hereinafter as a foaming ink) for causing expansion of a thermal expansion layer. As described later, in the embodiments, a pseudo-three-dimensional image forming system 50 is used as an example of the printing apparatus.
In this embodiment, the shaped object is expressed on the surface of the thermal expansion sheet 20 by forming convexities and/or irregularities by the bulging of a thermal expansion layer 22. Additionally, in this application, the term “shaped object” should be interpreted broadly to include simple shapes, geometric shapes, characters, decorations, and the like. The term “decorations” refers to objects that appeal to the aesthetic sense through visual and/or tactile sensation. The term “shaped (or molded)” does not simply refer to the forming of a shaped object, but should be construed to also include concepts such as adding decorations and forming decorations. The phrase “decorative shaped object” refers to a shaped object formed as a result of adding a decoration or forming a decoration. The term “shaped object” in the present embodiment is also termed a pseudo-three-dimensional image.
The shaped object according to the present embodiments uses as a reference a particular two-dimensional face (for example, an XY plane) within a three-dimensional space, and includes unevenness (for example, a Z axis) perpendicular to the face. Such shaped object is one example of three-dimensional (3D) images, but so as to distinguish from a three-dimensional image manufactured using a so-called 3D printing technique, the shaped object is called a 2.5-dimensional (2.5D) image or a pseudo-three-dimensional (preudo-3D) image. Furthermore, the technique for manufacturing the shaped object is one example of three-dimensional image printing techniques, but so as to distinguish from a so-called 3D printer, the technique is called a 2.5-dimensional (2.5D) printing technique or a pseudo-three-dimensional (pseudo-3D) printing technique.
The expression “colorless transparent photothermal conversion layer” in the present embodiment indicates that the photothermal conversion layer of ink 10 formed on the thermal expansion sheet 20 is not visible, or indicates that the photothermal conversion layer has enough color to enable slight visibility, and additionally indicates that the color of the thermal expansion sheet 20 is not masked, or is hardly masked, by the photothermal conversion layer.
In the present embodiment, the expression “colorless transparent photothermal conversion layer” can indicate that, upon comparison between the photothermal conversion layer and the surface of a thermal expansion sheet on which no photothermal conversion layer is formed, there is no color difference, or that the color difference is extremely small. Specifically, the comparison by the color difference is performed in the following manner. As illustrated in
The color difference of the present embodiment may be expressed using L*a*b* color coordinates, referred to hereinafter as the Lab color coordinate system. In this case, the color of the ink layer 25 (color of the region A illustrated in
ΔE*ab=[(ΔL*)2(Δa*)2+(Δb*)2]1/2 (Equation 1)
ΔL* is a difference between L* of the region A and L* of the region B. Δa* and Δb* are similarly differences in the values for the region A and the region B. The “*” of the expression L*a*b* is omitted below.
Here, the expression “no color difference” in the present embodiment means that the color difference ΔE of the Lab color coordinate system is included in a range of 1.6 to 3.2 or is below this range (ΔE is less than or equal to 3.2). The ΔE range of 1.6 to 3.2 is termed an “A-grade allowable difference”, is a color difference of a level that would be hardly noticed during side-by-side comparison of color, and is a color difference of a level that the colors would be generally considered to be the same color. The color difference ΔE is further preferably included in or below the range of 0.8 to 1.6. The ΔE range of 0.8 to 1.6 is termed an “AA-grade allowable difference”, and is a color difference of a level that would be slightly noticed during side-by-side comparison of color.
Further, the ink 10 according to this embodiment includes an inorganic infrared absorbing agent and, in addition thereto, may include any or all of ingredients selected from a solvent (water or organic solvent), a coloring agent (dye or pigment), a dispersant, a penetrant, an anti-drying agent, a pH adjuster, a preservative, a surfactant, a coloring agent (dye or pigment), a resin, and the like. The ink 10 may include other ingredients.
In a specific example in which the ink 10 is a water-based ink, the ink 10 includes an inorganic infrared absorbing agent, water, and an aqueous organic solvent. The aqueous organic solvent is not particularly limited, and examples thereof include polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkylene glycols such as ethylene glycol and triethylene glycol; glycerin; glycerols; lower alkyl ethers of polyhydric alcohols such as triethylene glycol monobutyl ether, ethylene glycol methyl (ethyl) ether, and diethylene glycol methyl (ethyl) ether; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone; ethanol; and isopropanol. These aqueous organic solvents are included in the ink 10 as the humectant, surfactant, and the like. Additionally, the ink 10 may include triethanolamine as the pH adjuster, and may also include other additives.
The ink 10 of the present embodiment is characterized as being transparent to visible light (hereinafter simply referred to as “transparent”) in a state in which an inorganic infrared absorbing agent is not intermixed. That is to say, the base of the ink 10 is characterized as being transparent. If a coloring agent is added to the ink 10, the ink 10 is characterized as being transparent in the state in which the inorganic infrared absorbing agent and the coloring agent are not included.
The expression “the ink 10 (base of the ink 10) not including the inorganic infrared absorbing agent is transparent” indicates that, whether the base of the ink 10 is printed on a black sheet or is printed on a white sheet, the color of the base material sheet is not masked or is hardly masked by the layer formed by the ink, and indicates that the color of the base material sheet can be visually recognized.
In one example, the ink 10 of this embodiment is used in the inkjet printing unit 52 illustrated in
As long as the formed photothermal conversion layer is colorless and transparent, the ink 10 may optionally include a coloring agent. For example, with an objective such as adjusting color of the ink 10 in order to approach the color of the surface of the thermal expansion sheet 20, the ink 10 may include the coloring agent. No particular limitation is placed on the color of the coloring agent. The color of the coloring agent may be appropriately selected from yellow, cyan, magenta, or any other freely-selected color. Moreover, as long as the photothermal conversion layer is colorless and transparent, the density of the coloring agent in the ink 10 is not particularly limited.
An inorganic material is used as the inorganic infrared absorbing agent. This inorganic material has higher absorptivity of light (absorptivity) in at least one region of the infrared light spectrum than in the visible light spectrum. In particular, the inorganic infrared absorbing agent preferably has a higher absorptivity of light in the near-infrared region than in the visible light spectrum. The visible light transparency of the ink 10 can be improved and the color of the ink 10 can be suppressed by selecting a material for which light transmittance (low absorptivity) in the visible light spectrum is high. By using a photothermal conversion layer printed using the ink 10, blurring of the color of the color ink layer can be prevented compared to when using traditional carbon-containing inks. Further, a colorless transparent photothermal conversion layer can be formed.
In this embodiment, examples of the inorganic infrared absorbing agent include metal oxides, metal borides, and metal nitrides.
Specific examples of the metal oxides include tungsten oxide compounds, indium oxide, indium tin oxide (ITO), antimony tin oxide (ATO), titanium oxide, zirconium oxide, tantalum oxide, cesium oxide, and zinc oxide.
A metal multi-boride compound is preferable and a metal hexaboride compound is particularly preferable as the metal boride, and one or a plurality of materials selected from the group consisting of lanthanum hexaboride (LaB6), cerium hexaboride (CeB6), praseodymium hexaboride (PrB6), neodymium hexaboride (NdB6), gadolinium hexaboride (GdB6), terbium hexaboride (TbB6), dysprosium hexaboride (DyB6), holmium hexaboride (HoB6), yttrium hexaboride (YB6), samarium hexaboride (SmB6), europium hexaboride (EuB6), erbium hexaboride (ErB6), thulium hexaboride (TmB6), ytterbium hexaboride (YbB6), lutetium hexaboride (LuB6), lanthanum hexaboride cerium ((La, Ce)B6), strontium hexaboride (SrB6), calcium hexaboride (CaB6), or the like can be used as the metal boride.
Examples of the metal nitrides include titanium nitride, niobium nitride, tantalum nitride, zirconium nitride, hafnium nitride, and vanadium nitride.
The tungsten oxide compound is expressed by the following formula:
MxWyOz (I)
Here, element M is at least one element selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn, W is tungsten, and O is oxygen.
The value of x/y preferably satisfies the relationship 0.001≤x/y≤1.1, and x/y is particularly preferably in the vicinity of 0.33. Additionally, i the value of z/y preferably satisfies the relationship 2.2≤z/y≤3.0. Specific examples of the formula of the tungsten oxide compound include Cs0.33WO3, Rb0.33WO3, K0.33WO3, and Tl0.33WO3.
Of the examples of the inorganic infrared absorbing agent described above, the metal hexaboride compound or the tungsten oxide compound is preferable, and the lanthanum hexaboride (LaB6) or cesium tungsten oxide are particularly preferable from the perspectives of obtaining high light absorptivity (low light transmittance) in the near-infrared region and high transmittance in the visible light spectrum. Any one of the inorganic infrared absorbing agents described above may be used alone, or a combination of two or more different materials may be used.
While not particularly limited thereto, the ink 10 of this embodiment includes the inorganic infrared absorbing agent at a concentration of 20 wt. % to 0.10 wt. %.
Values obtained by integrating the graph by wavelength correspond to amounts of energy absorbable by cesium tungsten oxide and the LaB6. Accordingly, provided that the foaming height of the thermally expandable material is not saturated, the ratio of these integral values is proportional to the foaming height. Specifically, the ratio of integral values of cesium tungsten oxide:LaB6 is 1:0.58. Thus, the foaming height obtainable in a photothermal conversion layer using LaB6 is about 0.58 times greater than the foaming height obtainable in a photothermal conversion layer using cesium tungsten oxide.
Next, the thermal expansion sheet 20, on which the photothermal conversion layer is to be formed by the ink 10, of this embodiment is described with reference to the drawings. As illustrated in
The base material 21 is implemented as a sheet-like member (including films). The base material 21 supports the thermal expansion layer 22 and the like. Examples of the base material 21 include paper such as high-quality paper, and commonly used plastic film such as polypropylene, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Additionally, fabric or the like may be used as the base material 21. The base material 21 has sufficient strength so that, when part or all of the thermal expansion layer 22 swells due to foaming, the opposite side (lower side as illustrated in
The thermal expansion layer 22 is formed on a first face (the upper face illustrated in
A thermoplastic resin selected from vinyl acetate polymers, acrylic polymers, and the like is used as a binder. The thermally expandable microcapsules include propane, butane, or a similar low boiling point volatile substance encapsulated in thermoplastic resin shells. The shells are formed from a thermoplastic resin selected from, for example, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof. An average particle size of the thermally expandable microcapsules is about 5 to 50 μm. When these microcapsules are heated to a thermal expansion start temperature or higher, the polymer shells that are made from the resin soften and the low boiling point volatile substance encapsulated therein vaporizes. The pressure resulting from this vaporization causes the capsules to swell. While dependent on the characteristics of the microcapsules to be used, the microcapsules swell to a size about five-times larger than that prior to swelling.
The ink receiving layer 23 is formed on the thermal expansion layer 22. The ink receiving layer 23 receives and holds ink used in a printing process, such as the ink of an inkjet printer. The ink receiving layer 23 is formed using a commonly used material in accordance with the ink to be used in the printing process. In an example in which water-based ink is used, the ink receiving layer 23 is formed using a material selected from porous silica, polyvinyl alcohol (PVA), or the like. Additionally, when the photothermal conversion layer is to be formed on the back face of the base material 21 as well, an ink receiving layer may also be formed on the back face of the base material 21. Further, depending on the type of the ink 10, the ink receiving layer 23 may be omitted. Thus in the case in which the ink receiving layer 23 is not formed, the ink layer 25 (photothermal conversion layer) is formed on the thermal expansion layer 22.
Pseudo-Three-Dimensional (Pseudo-3D) Image Forming System
Next, the pseudo-three-dimensional image forming system 50 that performs the printing on the thermal expansion sheet 20 to form a pseudo-three-dimensional image is described. As illustrated in
The control unit 51, the printing unit 52, and the expansion unit 53 are each mounted in the frame 60 as illustrated in
The control unit 51 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), 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 apparatus. As illustrated in
The printing unit 52 acquires from the control unit 51 color image data representing a color image (color ink layer 42) to be printed on the front face of the thermal expansion sheet 20, and prints the color image (color ink layer 42) using the color ink (cyan, magenta, and yellow) on the basis of the color image data. Black or gray color in the color ink layer is formed by blending the three CMY colors or by using a black color ink free of carbon black.
The printing unit 52 prints the front side photothermal conversion layer 41 on the basis of front face foaming data using the ink 10. This front face foaming data is data that indicates the portion of the front face of the thermal expansion sheet 20 to be foamed and caused to swell. Likewise, the printing unit 52 prints the back side photothermal conversion layer 43 on the basis of back face foaming data using the ink 10. This back face foaming data is data that indicates the portion of the back face of the thermal expansion sheet 20 to be foamed and caused to swell. The swelling height of the thermal expansion layer 22 corresponds to the density of the ink 10, and greater densities lead to greater swelling heights. As such, the shade of the ink 10 is determined by area coverage modulation or a similar technique such that the density of the ink 10 corresponds to the target height.
A print head 72 that executes the printing and ink cartridges 73 (73e, 73c, 73m, and 73y) containing ink are attached to the carriage 71. The ink cartridges 73e, 73c, 73m, and 73y respectively contain the ink 10 of this embodiment, and cyan (C), magenta (M), and yellow (Y) color ink. Each ink is discharged from a corresponding nozzle of the print head 72.
The carriage 71 is supported slidably on a guide rail 74, and is sandwiched between drive belts 75. The drive belts 75 are driven by the rotation of a motor 75m and, as a result, the carriage 71 moves in the main scanning direction D2 together with the print head 72 and the ink cartridges 73.
A platen 78 is provided in a lower portion of the frame 60, at a position facing the print head 72. The platen 78 extends in the main scanning direction D2 and constitutes a portion of a transport path of the thermal expansion sheet 20. A pair of feed rollers 79a (lower roller not illustrated in the drawings) and a pair of discharge rollers 79b (lower roller not illustrated in the drawings) are provided in the transport path of the thermal expansion sheet 20. The pair of feed rollers 79a and the pair of discharge rollers 79b transport the thermal expansion sheet 20 in the sub-scanning direction D1. Here, the thermal expansion sheet 20 is supported on the platen 78.
The printing unit 52 is connected to the control unit 51 via a flexible communication cable 76. The control unit 51 controls the print head 72, the motor 75m, the pair of feed rollers 79a, and the pair of discharge rollers 79b via the flexible communication cable 76. Specifically, the control unit 51 controls the pair of feed rollers 79a and the pair of discharge rollers 79b to transport the thermal expansion sheet 20. Additionally, the control unit 51 causes the motor 75m to rotate, thereby moving the carriage 71 and transporting the print head 72 to an appropriate position in the main scanning direction D2.
The expansion unit 53 applies heat to the thermal expansion sheet 20 to cause the thermal expansion sheet 20 to swell. As illustrated in
In one example, the irradiating unit is a halogen lamp that irradiates, at the thermal expansion sheet 20, light in the near-infrared region (750 to 1400 nm wavelength range), the visible light spectrum (380 to 750 nm wavelength range), or the intermediate infrared region (1400 to 4000 nm wavelength range). The wavelength of the light irradiated from the halogen lamp has the characteristics illustrated in
The display unit 54 is implemented as a touch panel or the like. In the example illustrated in
Pseudo-Three-Dimensional (Pseudo-3D) Image Forming Processing
Next, an explanation is given of the flow of processing whereby a pseudo-three-dimensional image is formed on the thermal expansion sheet 20 by the pseudo-three-dimensional image forming system 50, while referencing the flowchart illustrated in
First, a user prepares a thermal expansion sheet 20 on which a pseudo-three-dimensional image has not been formed, and designates the color image data, the front face foaming data, and the back face foaming data using the display unit 54. Then, the user inserts the thermal expansion sheet 20 into the printing unit 52 with the front face facing upward. The printing unit 52 prints a photothermal conversion layer (the front side photothermal conversion layer 41) on the front face of the inserted thermal expansion sheet 20 (step S1). The front side photothermal conversion layer 41 is formed by the ink 10 described above. The printing unit 52 discharges the ink 10 of this embodiment onto the front face of the thermal expansion sheet 20 in accordance with the designated front face foaming data. As a result, the front side photothermal conversion layer 41 is formed on the ink receiving layer 23, as illustrated in
Second, the user inserts the thermal expansion sheet 20 onto which the front side photothermal conversion layer 41 has been printed into the expansion unit 53 with the front face facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 20 from the front face (step S2). Specifically, the irradiating unit of the expansion unit 53 irradiates light onto the front face of the thermal expansion sheet 20. The front side photothermal conversion layer 41 printed on the front face of the thermal expansion sheet 20 absorbs the irradiated light, thereby generating heat. As a result, as illustrated in
Third, the user inserts the thermal expansion sheet 20, for which the front face has been heated and caused to swell, into the printing unit 52 with the front face facing upward. The printing unit 52 prints a color image (the color ink layer 42) on the front face of the inserted thermal expansion sheet 20 (step S3). Specifically, the printing unit 52 discharges the various cyan (C), magenta (M), and yellow (Y) inks onto the front face of the thermal expansion sheet 20 in accordance with the designated color image data. As a result, the color ink layer 42 is formed on the ink receiving layer 23 and the front side photothermal conversion layer 41, as illustrated in
Fourth, the user inserts the thermal expansion sheet 20, onto which the color ink layer 42 has been printed, into the expansion unit 53 with the back face facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 20 from the back face, and dries the color ink layer 42 formed on the front face of the thermal expansion sheet 20 (step S4). Specifically, the irradiating unit of the expansion unit 53 irradiates light onto the back face of the thermal expansion sheet 20, thereby heating the color ink layer 42 and volatilizing the solvent included in the color ink layer 42.
Fifth, the user inserts the thermal expansion sheet 20, onto which the color ink layer 42 has been printed, into the printing unit 52 with the back face facing upward. The printing unit 52 prints a photothermal conversion layer (the back side photothermal conversion layer 43) on the back face of the inserted thermal expansion sheet 20 (step S5). The back side photothermal conversion layer 43 is formed by the ink 10 of this embodiment in the same manner as the front side photothermal conversion layer 41 printed on the front face of the thermal expansion sheet 20. The printing unit 52 discharges the ink 10 onto the back face of the thermal expansion sheet 20 in accordance with the designated back face foaming data. As a result, the back side photothermal conversion layer 43 is formed on the back face of the base material 21, as illustrated in
Sixth, the user inserts the thermal expansion sheet 20, onto which the back side photothermal conversion layer 43 has been printed, into the expansion unit 53 with the back face facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 20 from the back face (step S6). Specifically, the irradiating unit (not illustrated in the drawings) of the expansion unit 53 irradiates light onto the back face of the thermal expansion sheet 20. The back side photothermal conversion layer 43 printed on the back face of the thermal expansion sheet 20 absorbs the irradiated light, thereby generating heat. As a result, as illustrated in
The pseudo-three-dimensional image is formed in the thermal expansion sheet 20 as a result of carrying out the procedures described above.
The ink 10 of this embodiment includes the inorganic infrared absorbing agent demonstrating higher absorptivity in at least one wavelength region of the infrared spectrum than in the visible light spectrum and, as a result, enables making of the formed photothermal conversion layer colorless and transparent. Thus a thermal expansion layer can be provided that has the colorless transparent photothermal conversion layer. By using the ink 10 of this embodiment, an ink, a printing apparatus, a printing method, and a manufacturing method for a shaped object can be provided that enable printing of a photothermal conversion layer that is colorless and transparent and thus has a greatly reduced effect of color on the pseudo-three-dimensional image.
Modified Example of Pseudo-Three-Dimensional (Pseudo-3D) Image Forming Processing
The pseudo-three-dimensional image forming processing is not limited to the process order illustrated in
For ease of description, the steps illustrated in
For embodiment, the pseudo-three-dimensional image forming processing is not limited to the process order illustrated in
The color printing step can also be performed prior to the front side conversion layer forming step and other steps. This is because the color of the ink 10 of this embodiment is particularly suppressed and, as such, the influence of the photothermal conversion layer on the color of the color layer can be suppressed even when the photothermal conversion layer is formed on the color image. In such cases, the color printing step, the drying step, the front side conversion layer forming step, and the front side swelling step are sequentially performed, and the back side conversion layer forming step and the back side swelling step are performed. In terms of the flowchart illustrated in
The color printing step and the front side conversion layer forming step may be combined to print the color ink layer and the front side conversion layer in a single step. In this embodiment, the color ink layer and the front side conversion layer are printed simultaneously.
Next, an explanation will be given of the flow of processing whereby a pseudo-three-dimensional image is formed on the thermal expansion sheet 20 by the pseudo-three-dimensional image forming system 50, while referencing the flowchart illustrated in
First, a user prepares a thermal expansion sheet 20 on which a pseudo-three-dimensional image has not been formed, and designates the color image data, the front face foaming data, and the back face foaming data using the display unit 54. Then the user inserts the thermal expansion sheet 20 into the printing unit 52 with the front face facing upward. Next, the printing unit 52 prints the front side conversion layer (the front side photothermal conversion layer) 41 and the color image (the color ink layer 42) on the front face of the inserted thermal expansion sheet 20 (step S21). Specifically, the printing unit 52 discharges, on the front face of the thermal expansion sheet 20, the ink 10 of this embodiment in accordance with the designated front face foaming data and the various cyan (C), magenta (M), and yellow (Y) inks in accordance with the designated color image data. As a result, the front side conversion layer 41 and the color ink layer 42 are formed on the ink receiving layer 23, as illustrated in
Second, the user inserts the thermal expansion sheet 20, onto which the front side conversion layer 41 and the color ink layer 42 have been printed, into the expansion unit 53 with the front face facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 20 from the front face (step S22). Specifically, the irradiating unit of the expansion unit 53 irradiates light onto the front face of the thermal expansion sheet 20. The front side conversion layer 41 printed on the front face of the thermal expansion sheet 20 absorbs the irradiated light, thereby generating heat. As a result, as illustrated in
Third, the user inserts the thermal expansion sheet 20 into the printing unit 52 with the back face facing upward. The printing unit 52 prints the back side photothermal conversion layer (the back side photothermal conversion layer 43) on the back face of the inserted thermal expansion sheet 20 (step S23). The printing unit 52 discharges the ink 10 onto the back face of the thermal expansion sheet 20 in accordance with the designated back face foaming data. As a result, the back side photothermal conversion layer 43 is formed on the back face of the base material 21, as illustrated in
Fourth, the user inserts the thermal expansion sheet 20, onto which the back side conversion layer 43 has been printed, into the expansion unit 53 with the back face facing upward. The expansion unit 53 heats the inserted thermal expansion sheet 20 from the back face (step S24). Specifically, the irradiating unit (not illustrated in the drawings) of the expansion unit 53 irradiates light onto the back face of the thermal expansion sheet 20. As a result, as illustrated in
The pseudo-three-dimensional image is formed in the thermal expansion sheet 20 as a result of carrying out the procedures described above. Since the color of the ink 10 of this embodiment is particularly suppressed, the influence of the ink 10 of the front side conversion layer 41 on the color of the color ink layer 42 can be suppressed. Accordingly, the front side conversion layer 41 and the color ink layer 42 can be formed in a single step, thereby simultaneously forming the front side conversion layer 41 and the color ink layer 42, as depicted in step S21 of this modified example.
This embodiment is not limited to the process order illustrated in
Additionally, instead of executing the front side swelling step immediately after the front side conversion layer forming step, it is possible to interpose another step such as the color printing step between the front side conversion layer forming step and the front side swelling step. In this case, an order is possible in which steps S1, S3 and S4 of
The front side conversion layer forming step, the color printing step, and the back side conversion layer forming step can be performed first, and then the front side swelling step and the back side swelling step can be performed. In this case, in terms of the flowchart illustrated in
The front side conversion layer forming step and the back side conversion layer forming step can be performed first, the front side swelling step and the back side swelling step can then be performed, and then the color printing step can be performed. In this case, for, example, in terms of the flowchart illustrated in
Modified Example of Ink 10
Although in the aforementioned embodiments an example is cited of a water-based ink for use in an inkjet printer, this example is not limiting. The ink 10 may be an ultraviolet-curable (UV-curable) ink for use in an inkjet printer. When the ink 10 is an ultraviolet-curable ink, the ink 10 includes an inorganic infrared absorbing agent, and further includes an ultraviolet-curable resin (ultraviolet-curable monomer, ultraviolet-curable oligomer) and a polymerization initiator. Cited examples of the ultraviolet-curable monomer include: isobornyl acrylate, phenoxyethyl acrylate, or the like mono-functional monomers; trimethylolpropane triacrylate, polyethylene glycol diacrylate, or the like poly-functional monomers; or the like. Further, polyester acrylates, polyether acrylates, epoxy acrylates, urethane acrylates, or the like are cited as the ultraviolet-curable oligomer. A urethane acrylate oligomer is preferably used as the ultraviolet-curable oligomer. Either a photo-cleavage type initiator or a hydrogen-abstraction type initiator can be used as the polymerization initiator, and a combination of multiple types of photo-polymerization initiators can be used. Acyl phosphine oxide compounds, acetophenone compounds, or the like are cited as the photo-cleavage type initiator; and benzophenone compounds, thioxanthone compounds, or the like are cited as the hydrogen-abstraction type initiator. In addition to these initiators, any known initiator can be used. Further, the ink 10 may further include solvents and additives.
In addition, the ink 10 may be a non-water-based (oil-based, solvent-based) ink for use in an inkjet printer. In this case, the ink 10 includes, in addition to the inorganic infrared absorbing agent, an organic solvent, resin, or the like. Cited organic solvents are: methyl alcohol, ethyl alcohol, or the like alcohols; acetone, methyl ethyl ketone, or the like ketones; methyl acetate, ethyl acetate, or the like esters; ethylene glycol, diethylene glycol, or the like glycols; and ethylene glycol monomethyl ether, glycol ethers, glycol acetates, saturated hydrocarbons, unsaturated hydrocarbons, or the like. Cited resins are: acrylic type resins, styrene-acrylic type resins, styrene-maleic acid type resins, rosin-based resins, epoxy type resins, silicone type resins, butyral resins, maleic acid resins, phenol resins, urethane resins, melamine resins, or the like. Known additives other than the aforementioned example additives may be used, and such known additives may be included in the ink 10.
If the ink 10 is the ultraviolet-curable type ink or the non-water-based ink, the ink receiving layer 23 may be omitted. Further, the drying step (step S4) illustrated in
In the description of the aforementioned embodiments, although an example is cited in which the ink is loaded into a cartridge set in an inkjet type printer, this example is not limiting. The ink of the present embodiments can be used in another type of printing (printing apparatus) such as an apparatus for screen printing, gravure printing, offset printing, flexographic printing, or the like. In this case, the ink receiving layer 23 can be omitted. Further, the printing steps illustrated in
The ink 10 may be any of the water-based ink, the oil-based ink, and the ultraviolet-curable ink in accordance with the printing method. In this case, the ink 10 includes materials in accordance with the respective printing method, such as, for example, solvents, resins for film formation, auxiliary agents, or the like.
When the ink 10 is the water-based ink, the ink includes the inorganic infrared absorbing agent and also water, an aqueous organic solvent, and a resin. Cited examples of the aqueous organic solvent, without particular limitation, are: polyethylene glycol, polypropylene glycol, or the like polyalkylene glycols; ethylene glycol, triethylene glycol, or the like alkylene glycols; glycerin, glycerols, triethylene glycol monobutyl ether, ethylene glycol methyl(ethyl) ether, diethylene glycol methyl(ethyl) ether, or the like polyalcohol lower-alkyl ethers; and N-methyl-2-pyrolidone, 1,3-dimethyl-2-imidazolidinone, ethanol, or isopropanol. Cited examples of the resin are: acrylic type resins, styrene-acrylic type resins, styrene-maleic acid type reins, rosin type resins, epoxy type resins, silicone type resins, butyral type resins, maleic acid resins, phenol resins urethane resins, melamine resins, or the like. The ink 10 may further include additives. In addition to these cited additives, any known material may be used as an additive.
If the ink 10 is the ultraviolet-curable ink, the ink 10 includes the inorganic infrared absorbing agent and further includes an ultraviolet-curable resin (ultraviolet-curable monomer, ultraviolet-curable oligomer) and a polymerization initiator. Cited ultraviolet-curable monomers are: isobornyl acrylate, phenoxyethyl acrylate, or the like mono-functional monomers; trimethylolpropane triacetate, propylene glycol diacrylate, or the like poly-functional monomers; or the like. Cited ultraviolet-curable oligomers are: polyester acrylates, polyether acrylates, epoxy acrylates, urethane acrylates, or the like. Urethane acrylate oligomers are preferably used. A photo-cleavage type initiator or a hydrogen-abstraction type initiator can be used as the polymerization initiator, and a combination of multiple types of photo-polymerization initiator can be used. Acyl phosphine oxide compounds, acetophenone compounds, or the like are cited as the photo-cleavage type initiator; and benzophenone compounds, thioxanthone compounds, or the like are cited as the hydrogen-abstraction type initiator. In addition to these initiators, any known initiator can be used. Further, the ink 10 may further include solvents and additives.
The ink 10 may be a non-water-based (oil-based, solvent-based) ink. In this case, the ink 10 includes, in addition to the inorganic infrared absorbing agent, an organic solvent, resin, or the like. Cited organic solvents are: methyl alcohol, ethyl alcohol, or the like alcohols; acetone, methyl ethyl ketone, or the like ketones; methyl acetate, ethyl acetate, or the like esters; ethylene glycol, diethylene glycol, or the like glycols; and ethylene glycol monomethyl ether, glycol ethers, glycol acetates, saturated hydrocarbons, unsaturated hydrocarbons, or the like. Cited resins are: acrylic type resins, styrene-acrylic type resins, styrene-maleic acid type resins, rosin-based resins, epoxy type resins, silicone type resins, butyral resins, maleic acid resins, phenol resins, urethane resins, melamine resins, or the like. Known additives other than the aforementioned example additives may be used, and such additives may be included in the ink 10.
Also in the case in which the ink 10 is used in the offset printing apparatus or the like, the resin included in the ink 10 preferably has rubber elasticity. In the case of the ultraviolet-curable type ink, urethane acrylates are cited as this type of resin, without particular limitation.
In addition, for example, in the case in which the offset printing apparatus is used, as illustrated in
A comparative example is illustrated in
An example is illustrated in
As illustrated in
Visual confirmation of the color of photothermal conversion was possible at black densities of about 0.02 or greater. Therefore, visual recognition of the color of the photothermal conversion layer (the ink) was not possible when the black density was set to 0.01. Accordingly, with the ink of the Example, swelling height, equivalent to that achieved by conventional black inks with a black density of 0.4 to 0.5, was obtained near the density at the limit of visual recognition. Furthermore, foaming and swelling of the thermal expansion layer could be caused even at black densities that are visually unrecognizable. Note that, while the swelling height decreased slightly at black densities of less than 0.01, the photothermal conversion layer can be made to foam higher than the values illustrated in
In order to show that the ink in a transparent state (base of the ink 10) free of the inorganic infrared absorbing agent does not mask the color of the sheet forming the base sheet, an ultraviolet-curable type clear inkjet printer-type ink free of the coloring agent or the like was used, and printing was performed on a black sheet. Applications were performed multiple times at the same density. Further, the multiple applications were performed so as to overlap the locations of prior applications. The Lab values and black densities of the ink layer in this case are listed in Table 1. The Lab values and density values were measured using an eXact reflection spectral densitometer (manufactured by Sakata INX ENG. Co., Ltd.). The Lab values and black densities indicated for an applications count of zero correspond to the color of the sheet. As listed in Table 1, although values changed due to printing of the ink on the sheet surface, there was little difference of the black density between the 0th and the 2nd-6th applications, and the Lab values among the 2nd-6th applications were almost the same. Thus the color of the sheet forming the base sheet was not masked by the clear type ink. In the present embodiment, the base of the ink 10 was transparent like the clear ink according to Example 2, the color of the sheet forming the base sheet was visually recognizable after printing, and the color was not masked by the ink layer.
For comparison, an ink layer was formed by an inkjet printer on a black sheet using an ultraviolet-curable type inkjet printer white ink, and results of measurement of the ink layer Lab values and black densities are listed in Table 2. Applications were performed multiple times at the same density. Further, the multiple applications were performed so as to overlap the locations of prior applications. The Lab values and density values were measured using an eXact reflection spectral densitometer (manufactured by Sakata INX ENG. Co., Ltd.). The Lab values and black densities indicated for an applications count of zero correspond to the color of the sheet. As listed in Table 2, the black density decreased to 0.04 by printing twice using white ink, and the black density at the 4th application reached 0. In this manner, the color of the base sheet was masked with each count of the overlapped printing, and the color of the sheet forming the base sheet became visually unrecognizable.
Next, in Example 3, an ink according to Example 3 was prepared by mixing cesium tungsten oxide in a medium (not including white pigment) including urethane acrylate as a UV-curable resin. Concentration of the cesium tungsten oxide in the ink was 10% by weight. A photothermal conversion layer was printed on a thermal expansion sheet (500 μm thick) by an offset printer using this ink. Density of printed photothermal conversion layer was set in 10% increments over a range of 0% to 100%. Further, the ink was printed as 3 or 4 overlapping applications. Prior to causing expansion of the thermal expansion layer, the respective color (Lab values) and black density were measured for the photothermal conversion layer using an eXact reflection spectral densitometer (manufactured by Sakata INX ENG. Co., Ltd.). Further, a halogen lamp (1,000 W, 2,500K) was moved at a speed of 20 mm/s over the thermal expansion sheet, the photothermal conversion layer was irradiated by electromagnetic radiation, and the thermal expansion layer was expanded. Thereafter, the color (Lab values) and black density of the photothermal conversion layer after thermal expansion layer expansion were measured using an eXact reflection spectral densitometer (manufactured by Sakata INX ENG. Co., Ltd.).
The Lab values of the photothermal conversion layer formed by printing three times prior to expansion of the thermal expansion layer are listed in Table 3. Further, ΔE listed in Table 3 was calculated using the aforementioned Equation 1 from the Lab values of the region of 0% density. Since the ink is not present in the 0% density region, the Lab values of the 0% density region correspond to the Lab values of the surface of the thermal expansion sheet. Further, black density, and the Hunter whiteness calculated from the Lab values using the below indicated Equation 2, are listed in Table 3.
Hunter whiteness=100−[(100−L)2+a2+b2]1/2 (Equation 2)
Next, Lab values of the photothermal conversion layer formed by printing three times and then expanding the thermal expansion layer are illustrated in Table 4. Further, ΔE listed in Table 4 was also calculated using the aforementioned Equation 1 from the Lab values of the region of 0% density. Further, black density, and the Hunter whiteness calculated from the Lab values using the above indicated Equation 2, are listed in Table 4.
Further,
Next, Lab values, occurring prior to expansion of the thermal expansion layer, of a photothermal conversion layer formed by printing four times are listed in Table 5. Further, ΔE listed in Table 5 was also calculated using the aforementioned Equation 1 from the Lab values of the region of 0% density. Further, black density, and the Hunter whiteness calculated from the Lab values using the above indicated Equation 2, are listed in Table 5.
Lab values of a photothermal conversion layer formed by printing four times and then expanding the thermal expansion layer are listed in Table 6. Further, ΔE listed in Table 6 was also calculated using the aforementioned Equation 1 from the Lab values of the region of 0% density. Further, black density, and the Hunter whiteness calculated from the Lab values using the above indicated Equation 2, are listed in Table 6.
Further,
Thus the ink 10 of the present embodiment can suppress color and can form a colorless transparent photothermal conversion layer.
The present disclosure is not limited to the aforementioned embodiments, and various types of modifications and applications are possible.
The colorless transparent photothermal conversion layer of the present embodiment can also be formed on the back face of the thermal expansion sheet. In this case, the color difference between the photothermal conversion layer and the thermal expansion sheet is calculated, in the same manner as in
In the present embodiment, a pseudo-three-dimensional image forming system 50 example is cited, as a printing apparatus that is equipped with a control unit 51, an expansion unit 53, or the like, although this example is not limiting, and the printing apparatus may be configured to consist of an inkjet type printing unit 52 such as that illustrated in
Further, although the aforementioned embodiment cites an example of a configuration that prints the photothermal conversion layer by heating a specific region of the thermal expansion sheet, as long as ink is used for heating a specific region, use is possible for articles other than the thermal expansion sheet.
Although the aforementioned embodiment cites an example of a configuration that forms the photothermal conversion layer on the front face and the back face of the thermal expansion sheet, this configuration is not limiting. In all aspects of the present disclosure, the photothermal conversion layer can be formed on the front face alone or on the back face alone.
Further, in the drawings, each of the layers of the thermal expansion sheet, the photothermal conversion layers (front face and back face), and the color ink layers are all exaggerated as required for description. Thus the illustrations of shapes, thicknesses, colors, or the like of such layers are not intended to be limiting.
The foregoing describes some example embodiments for explanatory purposes. Although the foregoing discussion has presented specific embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of the invention is defined only by the included claims, along with the full range of equivalents to which such claims are entitled.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-059401 | Mar 2017 | JP | national |
| 2018-029583 | Feb 2018 | JP | national |
| 2018-041457 | Mar 2018 | JP | national |
