Recording medium manufacturing method

Abstract

To improve the quality of a printed matter formed by black-and-white printing with laser marking and color printing with thermal transfer.SOLUTION: A recording medium manufacturing method comprises: a first step (step S10) in which an image processing device generates gradation data for laser marking and gradation data for color thermal transfer from an original image; a second step (step S30) in which a thermal transfer color printer forms a second coloring layer being second recording information by performing color printing with color thermal transfer on a first coloring layer laminated on a core base material of a recording medium on the basis of the gradation data for color thermal transfer; and a third step (step S40) in which a laser marking device forms first recording information by performing black-and-white printing with laser marking on the first coloring layer on the basis of the gradation data for laser marking.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for producing a recording medium. [Background technology]

[0002] Some recording media such as passports and security cards have a structure that prevents tampering. For example, Patent Document 1 discloses a counterfeit prevention medium for personal authentication that has a tamper-proof layer made of a laser-colorable substrate and invisible ink, making it easy to detect tampering.

[0003] In addition, some recording media have a structure to prevent counterfeiting. For example, Patent Document 2 discloses an information recording medium that can improve the printing quality of a laser coloring layer below a functional film layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 050223 [Patent Document 2] JP 2019-038168 A Summary of the Invention [Problem to be solved by the invention]

[0005] Some recorded information (printed matter) formed on a recording medium is made by overlapping a black-and-white print by laser marking and a color print by thermal transfer to prevent counterfeiting. However, if there is a positional deviation when printing the color print by thermal transfer, moire may occur. In addition, since the color development characteristics differ between the black-and-white print by laser marking and the color print by thermal transfer, the color tone of the recorded information that combines the black-and-white print and the color print may become unnatural.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to improve the print quality of recorded information formed by black and white printing by laser marking and color printing by thermal transfer. [Means for solving the problem]

[0007] Among the inventions disclosed in this application, a brief summary of representative inventions is as follows.

[0008] A recording medium manufacturing method according to a representative embodiment of the present invention includes a first step in which an image processing device generates gradation data for laser marking and gradation data for color thermal transfer from an original image, a second step in which a thermal transfer color printer forms a second color layer, which is second recording information, by performing color printing by color thermal transfer on a first color layer laminated on a core substrate of the recording medium based on the gradation data for color thermal transfer, and a third step in which a laser marking device forms first recording information by performing black-and-white printing by laser marking on the first color layer based on the gradation data for laser marking. In the first step, the image processing device generates gradation data for laser marking for each pixel, and in generating the gradation data for color thermal transfer, multiple areas including multiple pixels are set so as to cover the entire area of ​​the original image, the density of each color is set for each area, and printing dots are selected according to the set density. Furthermore, between the first and third steps, there is a fourth step in which the image processing device adjusts parameters relating to the irradiation of the laser light to adjust the graininess of the black-and-white print. Effect of the Invention

[0009] The effects obtained by the representative inventions disclosed in this application will be briefly described as follows.

[0010] That is, according to the representative embodiment of the present invention, it is possible to improve the print quality of recorded information formed by black and white printing by laser marking and color printing by thermal transfer. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing an example of a configuration of a recording medium according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing another example of the configuration of the recording medium. [Diagram 3] FIG. 1 is a diagram showing an example of a configuration of a record information forming system that forms record information on a recording medium. [Figure 4] FIG. 3 is a flow diagram showing an example of a method for producing the recording medium according to the first embodiment of the present invention. [Diagram 5] FIG. 11 is a flow diagram showing an example of a process for generating gradation data for forming record information from an original image. [Figure 6] FIG. 11 is a diagram showing an example of a method for adjusting gradation data for laser marking. [Figure 7] FIG. 2 is a process diagram showing an example of a method for producing the recording medium according to the first embodiment of the present invention. [Figure 8] 11A to 11C are diagrams showing a specific example of a method for forming record information. [Figure 9] FIG. 9 is a diagram showing an enlarged image of the recorded image in FIG. 8. [Figure 10] FIG. 11 is a flow diagram showing an example of a method for producing a recording medium according to a second embodiment of the present invention. [Figure 11] 6 is a process diagram showing an example of a method for producing a recording medium according to a second embodiment of the present invention. [Figure 12] FIG. 11 is a cross-sectional view showing an example of the configuration of a recording medium according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Embodiment 1) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment described below is an example for realizing the present invention, and does not limit the technical scope of the present invention. In the examples, members having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted unless particularly necessary.

[0013] <Storage medium configuration> Fig. 1 is a diagram showing an example of the configuration of a recording medium according to the first embodiment of the present invention. Fig. 1(a) is a plan view of a recording medium 10, and Fig. 1(b) is a cross-sectional view of the recording medium 10. Fig. 1(b) shows a cross-sectional view of an area in which recording information of a color print is formed.

[0014] The recording medium 10 is, for example, a passport or a security card, but is not limited to these and may be, for example, a membership card or a patient registration card. As shown in Fig. 1(a), recorded information 20 (20a, 20b, 20c, etc.) such as predetermined characters, symbols, photographs, etc. is formed on the recording medium 10.

[0015] 1(b), the recording medium 10 is configured by laminating layers such as a core substrate 1, a first color-forming layer 2, a first protective layer 3, a second color-forming layer 4 (second recorded information 20B), and a second protective layer 5. Although the layers are laminated only on one surface of the core substrate 1 in FIG. 1(b), these layers may also be laminated on the other surface (second surface) of the core substrate 1 opposite to the one surface (first surface).

[0016] When the recorded information 20 is composed only of achromatic colors such as black or gray, such as characters or symbols, black and white printing is performed by laser marking on the first color-forming layer 2. Note that the black and white printing mentioned here also includes so-called grayscale printing.

[0017] On the other hand, when the recorded information 20 is in color such as a photograph, black and white printing is performed on the first coloring layer 2 by laser marking, and color printing is performed by thermal transfer. In this manner, the first recorded information 20A formed on the first coloring layer 2 and the second recorded information 20B, which is the second coloring layer 4, are overlapped to form the color recorded information 20.

[0018] The core substrate 1 is a sheet-like substrate mainly composed of, for example, resin. Examples of resins that can be used to form the core substrate 1 include polycarbonate (PC), plant-derived polycarbonate (bio-PC), polyethylene terephthalate (PET), amorphous polyethylene terephthalate (PETG), polyvinyl chloride (PVC), and ABS resin. The thickness of the core substrate 1 is preferably, for example, 10 to 500 μm.

[0019] The first coloring layer 2 is a layer on which black and white printing is performed by laser marking. That is, black and white printing of an achromatic color such as black or gray is performed by irradiating the first coloring layer 2 with laser light.

[0020] The first coloring layer 2 is, for example, the above-mentioned resin to which a laser light absorbing agent that absorbs the irradiated laser light has been added as an additive. The laser light absorbing agent is, for example, a material that can absorb laser light and convert it into thermal energy. When the laser light absorbing agent absorbs the laser light, the surrounding resin is carbonized by the thermal energy, and the laser marking portion 2a is formed in which the resin is colored black, gray, or the like. The first recorded information 20A, which is a black and white image, is then formed by combining the laser marking portion 2a with a laser non-irradiated area that is not irradiated with laser light.

[0021] Examples of laser light absorbents include those containing a dye and a silicon-containing inorganic compound, a dye containing silicon, a radiation absorbing substance such as a metal silicate, an inorganic filler such as hydrated alumina, a pigment containing a phosphate, a non-white metal titanate, a black organic dye, a non-black inorganic lead compound, graphite, carbon black, graphite, a metal hydroxide and / or a metal hydrate compound and a colorant, and the like.

[0022] The laser beam absorbent is appropriately selected depending on the compatibility between the wavelength (wavelength range) of the laser beam and the resin, etc. The amount of the laser beam absorbent added is appropriately set in consideration of the energy absorption efficiency, the effect on the physical properties of the resin in the first coloring layer 2, etc.

[0023] Examples of laser light that can be used include solid lasers such as ruby ​​lasers, titanium sapphire lasers, and YAG lasers (Nd:YAG lasers are infrared), gas lasers such as carbon dioxide lasers (infrared), helium neon lasers (red), argon ion lasers (mainly blue or green), and excimer lasers (mainly ultraviolet), and semiconductor lasers.

[0024] Fig. 2 is a cross-sectional view showing another example of the configuration of a recording medium. Fig. 2 is the same as Fig. 1(b) except that the configuration of the first coloring layer 2 is different. The first coloring layer 2 in Fig. 2 is configured by laminating a black layer 2m and a concealing layer 2n from the core substrate 1 side. The black layer 2m is made by adding a black laser light absorbing agent such as carbon black or graphite to the above-mentioned resin.

[0025] The concealing layer 2n is formed by coating an ink, in which a white pigment such as titanium oxide, calcium carbonate, or zinc oxide is dispersed in a known binder resin, on the black layer 2m in a layered manner.

[0026] The first protective layer 3 is a layer that protects the first coloring layer 2. The first protective layer 3 is made of a transparent material that transmits laser light.

[0027] The second coloring layer 4 is a layer formed by color printing by thermal transfer. For example, an ink ribbon for color printing arranged on the first protective layer 3 is heated using a known heat source such as a thermal head or a heat roller, thereby thermally transferring the second coloring layer 4 onto the first protective layer 3. The formed second coloring layer 4 becomes the above-mentioned second color recorded information 20B. The first recorded information 20A and the second recorded information 20B form the color recorded information 20.

[0028] The second protective layer 5 is a layer that protects the second protective layer 5 (second recorded information 20B). The second protective layer 5 is made of a transparent material.

[0029] In addition to these layers, the recording medium 10 may also include an optical device layer having, for example, a hologram or a diffraction grating.

[0030] <Recording information formation system> Next, a description will be given of a method for manufacturing the recording medium 10. First, a description will be given of a recorded information forming system for forming recorded information on the recording medium 10 by performing black-and-white printing and color printing.

[0031] Fig. 3 is a diagram showing an example of the configuration of a record information forming system that forms record information on a recording medium. The record information forming system 500 in Fig. 3 includes an image processing device 100, a laser marking device 200, and a thermal transfer color printer 300. The image processing device 100 transmits and receives various information such as gradation data for printing between the laser marking device 200 and the thermal transfer color printer 300. The laser marking device 200 and the thermal transfer color printer 300 may be connected.

[0032] The image processing device 100 generates gradation data for laser marking and gradation data for color thermal transfer from an original image for generating the recording information 20. As shown in Fig. 3, the image processing device 100 includes, for example, a computer 101, a memory 102, a storage device 103, and the like. The image processing device 100 is not particularly limited as long as it includes these components. Therefore, for example, a personal computer or the like can be used as the image processing device 100.

[0033] The storage device 103 stores various programs such as a basic program for operating the image processing device 100, a gradation data generating program for generating gradation data, etc. The storage device 103 may also store an original image input from the outside, generated gradation data, etc.

[0034] The memory 102 temporarily holds various types of information, such as programs read from the storage device 103 and the results of calculations by the computer 101.

[0035] The computer 101 includes a processor such as a CPU. The computer 101 reads out various programs from the storage device 103 and stored in the memory 102, and executes them to realize functional blocks that fulfill the functions of the programs, such as a block that generates gradation data, on the computer 101. Note that the processing executed by the computer 101 includes processing executed by the functional blocks realized on the computer 101.

[0036] The laser marking device 200 performs black and white printing by laser marking processing based on the laser marking gradation data generated by the image processing device 100. The thermal transfer color printer 300 performs color printing by color thermal transfer based on the color thermal transfer gradation data generated by the image processing device 100.

[0037] <Method of manufacturing recording medium> Next, a specific description will be given of a method for manufacturing the recording medium 10. Fig. 4 is a flow diagram showing an example of a method for manufacturing the recording medium according to the first embodiment of the present invention. In Fig. 4, steps S10 to S40 are shown as the method for manufacturing an information medium.

[0038] <<Gradation data generation>> In step S10, the computer 101 of the image processing device 100 processes an original image acquired from outside, and generates gradation data for laser marking and gradation data for color thermal transfer from the original image such as a photograph.

[0039] Fig. 5 is a flow diagram showing an example of a process for generating gradation data for forming record information from an original image. In Fig. 4, steps S11 to S15 are illustrated as an example of the color data generation process.

[0040] In step S11, the computer 101 performs RGB color separation on the original image and obtains the first gradation data (R1, G1, B1) of each color for each pixel. The first gradation data (R1, G1, B1) may be held in the memory 102 or may be stored in the storage device 103.

[0041] Next, in step S12, the computer 101 converts the first RGB gradation data (R1, G1, B1) generated in step S11 into second CMYK gradation data (C, M, Y, K). Specifically, the computer 101 converts the first gradation data (R1, G1, B1) into the second gradation data (C, M, Y, K) using, for example, the gradation data conversion formulas (Formulas 1 to 4) shown below. Note that Formula 4 indicates that the gradation data of the K component is the minimum value of each gradation data of CMK. The second gradation data (C, M, Y, K) may be held in the memory 102 or may be stored in the storage device 103.

[0042] C=((255-R1-K) / (255-K))×255 (Formula 1) M=((255-G1-K) / (255-K))×255 (Formula 2) Y=((255-B1-K) / (255-K))×255 (Formula 3) K=min(255-R1, 255-G1, 255-B1) (Formula 4) Next, in step S13, the computer 101 generates color thermal transfer gradation data (Rc, Gc, Bc). Since the printing characteristics differ for each thermal transfer color printer, in step S13, the density (gradation) of each color is adjusted according to the printer characteristics.

[0043] On the other hand, in color printing by a thermal transfer color printer, the density of each color is adjusted by area gradation because it is not possible to adjust the density for each dot. The computer 101 sets multiple regions (for example, a matrix of 16 pixels x 16 pixels) containing multiple pixels so as to cover the entire area of ​​the original image, and sets the density of each color for each region. The computer 101 then selects the printing dots according to the set densities.

[0044] Then, the computer 101 generates color thermal transfer gradation data (Rc, Gc, Bc) for each dot selected for each color using the second gradation data (C, M, Y) of the CMY components and the gradation data conversion formulas (Formulas 5 to 7) shown below. The color thermal transfer gradation data may be held in the memory 102 or may be stored in the storage device 103.

[0045] Rc=255-Y (Formula 5) Gc=255-M (Formula 6) Bc=255-C (Formula 7) The computer 101 may generate data including gradation data of all dots for each color as color thermal transfer gradation data, or may generate data including gradation data of all dots of all colors as color thermal transfer gradation data. Such color thermal transfer gradation data is bitmap data of CMY components.

[0046] Next, in step S14, the computer 101 generates laser marking gradation data (Rl, Gl, Bl) for each pixel. Note that in black and white printing by laser marking, it is possible to adjust the density (gradation) for each pixel.

[0047] Specifically, the computer 101 generates laser marking grayscale data (Rl, Gl, Bl) using, for example, the second grayscale data of the K component and the grayscale data conversion formulas (Formulas 8 to 10) shown below. As shown below, each component (Rl, Gl, Bl) of the laser marking grayscale data has the same value. The laser marking grayscale data may be held in the memory 102 or may be stored in the storage device 103.

[0048] Rl=255-K (Equation 8) Gl=255-K (Formula 9) Bl=255-K (Formula 10) The computer 101 may generate data including gradation data of all pixels for each color as the gradation data for laser marking, or may generate data including gradation data of all colors of all pixels as the gradation data for laser marking. Such gradation data for laser marking is bitmap data of the K component.

[0049] Next, in step S15, the computer 101 adjusts the laser marking gradation data (Rl, Gl, Bl). The laser marking gradation data is adjusted according to the characteristics of the printing material (for example, the first color layer 2).

[0050] The computer 101 adjusts the laser marking gradation data so that the change in gradation data and the change in density have a natural relationship based on the relationship between the laser marking gradation data and the density before the adjustment. Specifically, the laser marking gradation data is adjusted so that the relationship between the change in gradation data and the change in density approaches linearity.

[0051] The computer 101 creates in advance a laser marking gradation data conversion table LUT that associates pre-adjustment laser marking gradation data with post-adjustment laser marking gradation data for each printing material, and stores the table in the storage device 103. The laser marking gradation data conversion table LUT may be generated by another device.

[0052] FIG. 6 is a diagram showing an example of a method for adjusting gradation data for laser marking. FIG. 6(a) is a diagram showing the relationship between gradation data for laser marking and density before adjustment. FIG. 6(b) is a diagram showing the relationship between gradation data for laser marking and density after adjustment. Note that density is, for example, the density of black, and the higher the density value, the stronger the black color becomes. FIG. 6(c) is a color sample for adjusting gradation data for laser marking. FIG. 6(c) shows multiple stages of color from 1st stage to 11th stage, starting from the white side.

[0053] As shown in Figure 6(a), before adjusting the gradation data for laser marking, the relationship between gradation data and density is significantly different from linear. For example, when the gradation data is about 0 to 100, the density change is small. When the gradation data is about 100 to 200, the density rises sharply. Then, for gradation data above that, the density change becomes small again. On the other hand, after adjusting the gradation data for laser marking, the relationship between gradation data and density shown in Figure 6(b) is closer to linear.

[0054] As a method for adjusting such laser marking grayscale data, for example, gamma conversion is used. The computer 101 performs gamma conversion on the 11 grayscale data P1 to P11 shown in Fig. 6(a), for example, to generate adjusted laser marking grayscale data P1' to P11'. The converted grayscale data P1' to P11' are shown in Fig. 6(b). That is, these grayscale values ​​P1' to P11' correspond to the first to eleventh stages of the color sample shown in Fig. 6(c), respectively. In this way, the grayscale data is adjusted between colors of the same stage by gamma conversion.

[0055] On the other hand, the gradation data corresponding to colors other than these 11 levels is adjusted, for example, by an interpolation process using adjusted gradation data for laser marking of neighboring colors of each level.

[0056] Then, the computer 101 generates a laser marking gradation data conversion table LUT in which each gradation data before and after the adjustment is associated with each other. The generated laser marking gradation data conversion table LUT is stored in the storage device 103, for example.

[0057] By these steps S11 to S15, the gradation data for laser marking and the gradation data for color thermal transfer are generated, respectively. Note that the order of steps S13 to S15 can be changed as appropriate.

[0058] <<Adjusting the graininess of black and white prints>> Even if black and white printing is performed using the laser marking gradation data (Rl, Gl, Bl) generated in step S10, the graininess of the black and white print may be coarse. If the graininess is coarse, the resolution may decrease and moire may occur due to interference with dots in color printing, which may reduce the print quality of the recorded information in the printed matter.

[0059] Therefore, in step S20, the graininess of the black-and-white print is adjusted. As a method of adjusting the graininess, the computer 101 adjusts various parameters related to the irradiation of the laser light, for example. Parameters to be adjusted include, for example, the laser power (laser output), pixel interval, frequency (period), and print speed (scanning speed, etc.). The various adjusted parameters are stored in the storage device 103 or the like in association with the corresponding gradation data for laser marking (Rl, Gl, Bl). The adjustment of the graininess of the black-and-white print is performed so that the graininess of the black-and-white print becomes equivalent to the graininess of, for example, a silver halide photograph.

[0060] 4, the case where step S20 is executed between step S10 and step S30 is shown, but the present invention is not limited to this. That is, step S20 may be executed after step S10 and before step S40.

[0061] <<Color printing>> Next, in step S30, color printing is performed by thermal transfer. FIG. 7 is a process diagram showing an example of a method for manufacturing a recording medium according to the first embodiment of the present invention. FIG. 7 shows cross-sectional views of each process corresponding to steps S30 and S40 in FIG. 4. The image processing device 100 outputs color thermal transfer gradation data (Rc, Gc, Bc) and the like to the thermal transfer color printer 300. Note that this information may be input to the thermal transfer color printer 300 in advance. Also, this information may be supplied to the thermal transfer color printer 300 from, for example, a server (not shown) connected to a network.

[0062] An ink ribbon RIB for color thermal transfer is placed on the first protective layer 3 of the recording medium 10. The thermal transfer color printer 300 heats the ink ribbon RIB dot by dot using a heat source such as a thermal head or a heat roller based on color thermal transfer gradation data (Rc, Gc, Bc) and the like (FIGS. 7(a)-7(b)), thereby forming a second coloring layer 4 on the first protective layer 3 (FIG. 7(c)). This second coloring layer 4 is the second recording information 20B of the color image. When color printing is completed, the ink ribbon RIB is removed, and a second protective layer 5 is formed on the second coloring layer 4 (FIG. 7(d)).

[0063] <<Black and white print>> Next, in step S40, black and white printing is performed by laser marking. The image processing device 100 outputs various information such as laser marking gradation data (Rl, Gl, Bl) corresponding to the recording information to be formed on the recording medium 10 and various corresponding adjusted parameters to the laser marking device 200. Note that this information may be input to the laser marking device 200 in advance. Also, this information may be supplied to the laser marking device 200 from, for example, a server (not shown) connected to a network.

[0064] The laser marking device 200 irradiates the recording medium 10 with laser light LAZ based on the laser marking gradation data (Rl, Gl, Bl) and various adjusted parameters. As a result, a laser marking portion 2a is formed in the area of ​​the first coloring layer 2 irradiated with the laser light LAZ. Then, the first recorded information 20A of a black and white image is formed on the first coloring layer 2 by combining the laser marking portion 2a with a non-laser irradiated area where the laser light LAZ is not irradiated (FIG. 7(e)). In this embodiment, as shown in FIG. 7(e), the laser light LAZ is irradiated to the first coloring layer 2 through the second coloring layer 4.

[0065] When the irradiation of the laser light LAZ is finished, the process of forming the record information 20 is completed (FIG. 7(f)). Through these steps, the recording medium is manufactured.

[0066] <Major Effects of the Present Embodiment> According to this embodiment, in step S10, the image processing device 100 generates gradation data for laser marking (Rl, Gl, Bl) for each pixel, and in generating gradation data for color thermal transfer (Rc, Gc, Bc), multiple areas containing multiple pixels are set so as to cover the entire area of ​​the original image, the density of each color is set for each area, and printing dots are selected according to the set density.

[0067] According to this configuration, the method of generating gradation data differs between black and white printing and color printing, making it possible to improve the print quality of the recorded information formed by black and white printing by laser marking and color printing by thermal transfer.

[0068] Furthermore, according to this embodiment, the image processing device 100 adjusts the laser marking gradation data (Rl, Gl, Bl) based on the relationship between the laser marking gradation data and the density so that the relationship between the change in the laser marking gradation data and the change in density approaches linear. This configuration makes it possible to adjust the laser marking gradation data to an appropriate value according to the characteristics of the printing material (e.g., the first color layer 2).

[0069] According to this embodiment, the image processing device adjusts the laser marking gradation data corresponding to each of the multiple levels of color of the color sample, and adjusts the laser marking gradation data corresponding to colors other than the multiple levels of color by an interpolation process using the adjusted laser marking gradation data of the neighboring colors. With this configuration, it is possible to reduce the amount of calculation required for adjusting the laser marking gradation data.

[0070] In addition, in this embodiment, the image processing device 100 adjusts parameters related to the irradiation of the laser light LAZ (for example, laser power, pixel interval, frequency, and printing speed). With this configuration, it is possible to adjust the graininess of black and white prints to make the particles less noticeable. This makes it possible to suppress the occurrence of moire due to interference between dots in color prints.

[0071] [Example] Here, an example according to the present embodiment will be described. FIG. 8 is a diagram showing a specific example of a method for forming recorded information. FIG. 8(a) is a specific example of the first recorded information 20A formed on the first color-developing layer 2 by black-and-white printing. FIG. 8(b) is a specific example of the second recorded information 20B formed on the first protective layer 3 by color printing. These pieces of recorded information (20A, 20B) are formed based on each gradation data generated from an original image. Although FIG. 8(b) is shown in black-and-white in the drawing, it is actually displayed in color. And FIG. 8(c) shows color recorded information 20 formed by overlapping the first recorded information 20A and the second recorded information 20B.

[0072] Fig. 9 shows an enlarged image of the recorded image in Fig. 8. Fig. 9(a) shows an enlarged image of Fig. 8(b). Fig. 9(a) shows a black and white print with adjusted graininess. As shown in Fig. 9(a), by adjusting the parameters, the graininess is not noticeable even when the black and white print is enlarged.

[0073] Fig. 9(b) is an enlarged view of the eye and its vicinity of the person in Fig. 8(c). Fig. 9(c) is a further enlarged view of the eye in Fig. 9(b). In the enlarged views of Fig. 9(b) and Fig. 9(c), the dots of the color print are visible, but the particles are almost invisible in the black-and-white print with adjusted graininess. Therefore, with such recorded information 20, it can be seen that the dots of the color print and the particles of the black-and-white print do not interfere with each other, improving the print quality of the recorded information.

[0074] 8 and 9 were created using as the original image an image with identification number "N1" of the "ISO / JIS-SCID sample" published in the "High-definition Color Digital Standard Image Data" issued by the Japan Standards Association. Also, "ISO 400" attached to Fig. 8 indicates the resolution of the original image. The indication of the resolution is requested when using the image, and the indication does not limit the scope of this application.

[0075] (Embodiment 2) Next, a description will be given of embodiment 2. Fig. 10 is a flow diagram showing an example of a method for manufacturing a recording medium according to embodiment 2 of the present invention. As shown in Fig. 10, in this embodiment, the order of the black-and-white printing process and the color printing process is switched.

[0076] <<Black and white print>> Next, in step S40, black and white printing is performed by laser marking. Figure 11 is a process diagram showing an example of a method for producing a recording medium according to the second embodiment of the present invention. Figure 11 shows cross-sectional views of each process corresponding to steps S40 and S30 in Figure 10.

[0077] The laser marking device 200 irradiates the recording medium 10 with the laser light LAZ based on the laser marking gradation data (Rl, Gl, Bl) and the various adjusted parameters. As a result, the laser marking device 200 forms a laser marking portion 2a in the area of ​​the first coloring layer 2 irradiated with the laser light LAZ. Then, the first recorded information 20A of a black and white image is formed on the first coloring layer 2 by combining the laser marking portion 2a with the laser non-irradiated area where the laser light LAZ is not irradiated (FIGS. 11(a) to 11(b)). In this embodiment, since black and white printing is performed before color printing, the laser light LAZ is irradiated to the first coloring layer 2 without passing through the second coloring layer 4, as shown in FIG. 11(b).

[0078] When the irradiation of the laser light LAZ is completed, the first protective layer 3 is formed on the first coloring layer 2 (FIG. 11(c)). Note that the irradiation of the laser light LAZ may be performed after the first protective layer 3 is formed on the first coloring layer 2.

[0079] <<Color printing>> Next, in step S30, color printing is performed by thermal transfer. First, an ink ribbon RIB for color thermal transfer is placed on the first protective layer 3 of the recording medium 10 (FIG. 11(d)). Then, the thermal transfer color printer 300 forms a second color-forming layer 4 (second recording information 20B) on the first protective layer 3 by heating the ink ribbon RIB dot by dot using a heat source such as a thermal head or a heat roller based on the color thermal transfer gradation data (Rc, Gc, Bc) and the like (FIG. 11(e)). Then, when the color printing is completed, the ink ribbon RIB is removed, and a second protective layer 5 is formed on the second color-forming layer 4 (FIG. 11(f)).

[0080] When the color printing is finished, the process of forming the record information 20 is completed. Through these steps, the recording medium is manufactured.

[0081] In this embodiment as well, the same effects as those in the first embodiment described above can be obtained.

[0082] (Embodiment 3) Next, a third embodiment will be described. Fig. 12 is a cross-sectional view showing an example of the configuration of a recording medium according to the third embodiment of the present invention. As shown in Fig. 12, in a recording medium 10A of this embodiment, the lamination order of the first color forming layer 2 and the second color forming layer 4 (second recording information 20B) is reversed. This is different from the first and second embodiments described above.

[0083] In FIG. 12, the stacking order of the first protective layer 3 and the second protective layer 5 is also interchanged, but the present invention is not limited to this configuration.

[0084] The formation of the record information 20 on the recording medium 10A is carried out by the above-mentioned color printing process (step S30) and black-and-white printing process (step S40).

[0085] In this embodiment as well, the same effects as those in the first and second embodiments described above can be obtained.

[0086] The present invention is not limited to the above-described embodiment, and includes various modified examples. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and a part of the configuration of one embodiment can be added to the configuration of another embodiment. A part of the configuration of each embodiment can be added, deleted, or replaced with another configuration. The components and relative sizes shown in the drawings are simplified and idealized to easily explain the present invention, and may have a more complicated shape in actual implementation. [Explanation of symbols]

[0087] 2...first color-forming layer, 4...second color-forming layer, 10, 10A...recording medium, 20...recorded information, 20A...first recorded information, 20B...second recorded information, 100...image processing device, 200...laser marking device, 300...thermal transfer color printer.

Claims

1. A first step in which an image processing device generates laser marking gradation data and color thermal transfer gradation data from an original image; a second step in which the thermal transfer color printer performs color printing by color thermal transfer on the first color layer laminated on the core substrate of the recording medium based on the color thermal transfer gradation data, thereby forming a second color layer which is second recording information; a third step of forming first record information by performing black-and-white printing on the first color-developing layer by laser marking using a laser marking device based on the laser marking gradation data; having In the first step, The image processing device includes: generating the laser marking gradation data for each pixel; In generating the color thermal transfer gradation data, a plurality of regions each including a plurality of pixels is set so as to cover the entire area of ​​the original image, a density of each color is set for each of the regions, and printing dots are selected according to the set density; a fourth step between the first step and the third step, in which the image processing device adjusts parameters related to the irradiation of the laser light to adjust graininess of the black-and-white print; A method for manufacturing a recording medium.

2. 2. The method for producing a recording medium according to claim 1, the image processing device adjusts the laser marking gradation data in accordance with the characteristics of the first color-forming layer; A method for manufacturing a recording medium.

3. 3. The method for producing a recording medium according to claim 2, the image processing device adjusts the laser marking gradation data based on the relationship between the laser marking gradation data and the density so that the relationship between the change in the laser marking gradation data and the change in the density approaches linearity; A method for manufacturing a recording medium.

4. 4. The method for producing a recording medium according to claim 3, The image processing device includes: adjusting the laser marking gradation data corresponding to each of the multiple levels of color of the color sample; For the laser marking gradation data corresponding to a color other than the plurality of levels of color, the laser marking gradation data is adjusted by an interpolation process using the laser marking gradation data of the neighboring levels of color that have been adjusted. A method for manufacturing a recording medium.

5. The method for producing a recording medium according to claim 1, The parameter includes any one of laser power, pixel spacing, frequency, and print speed. A method for manufacturing a recording medium.

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