Drawing system and drawing method

Abstract

A drawing system according to one embodiment of the present invention comprises a light source unit and a scanning unit. The light source unit generates multiple laser beams including wavelengths that are different from each other and that correspond to absorption wavelengths of a photothermal converter contained in a recording medium. The scanning unit scans the laser beams over the surface of the recording medium in a state in which spots irradiated by the multiple laser beams are lined up at a predetermined spacing in a direction orthogonal to or obliquely intersecting the directions in which the laser beams are scanned.

Description

[Technical Field]

[0001] This disclosure relates to a drawing system and a drawing method. [Background technology]

[0002] As an alternative display medium to printed materials, recording media that reversibly record and erase information using heat, so-called reversible thermal recording media, have been developed. In a reversible thermal recording media, for example, multiple reversible thermal recording layers with different photothermal conversion wavelengths are stacked with an insulating layer in between. By irradiating the reversible thermal recording media with laser light of a predetermined wavelength, heat is selectively generated in a specific reversible thermal recording layer, and information is recorded or erased by the action of the generated heat, causing color development or decolorization (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2004-188827 [Overview of the project]

[0004] Incidentally, when writing or erasing the same pixel in each reversible thermal recording layer simultaneously, thermal crosstalk can occur between two adjacent reversible thermal recording layers in the stacking direction, potentially leading to unintended writing or erasing. Therefore, it is desirable to provide a drawing system and drawing method that makes unintended writing or erasing less likely.

[0005] A writing system according to one embodiment of the present disclosure is a writing system that performs writing on a recording medium in which a plurality of recording layers, each composed of different color-producing compounds and different photothermal converters, are stacked with an insulating layer in between. The writing system comprises a light source unit and a scanning unit. The light source unit generates a plurality of laser beams, each having a different wavelength and including a wavelength corresponding to the absorption wavelength of the photothermal converter. The scanning unit irradiates the surface of the recording medium with the plurality of laser beams generated by the light source unit through a predetermined gap, and scans the plurality of laser beams on the surface of the recording medium in synchronization in the same direction. The scanning unit scans the surface of the recording medium with the plurality of laser beams arranged at a predetermined gap in a direction perpendicular to or obliquely intersecting the scanning direction of the plurality of laser beams.

[0006] In a drawing system according to one embodiment of this disclosure, multiple laser beams are scanned on the surface of a recording medium with irradiation spots generated by multiple laser beams from a light source unit, arranged at predetermined gaps in directions perpendicular to or diagonally intersecting the scanning direction of the multiple laser beams. This reduces thermal crosstalk between adjacent recording layers in the stacking direction. As a result, the possibility of unexpected writing or erasing can be reduced.

[0007] A writing method according to one embodiment of the present disclosure is a method for writing on a recording medium in which a plurality of recording layers, each composed of different color-producing compounds and different photothermal converters, are stacked with respect to an insulating layer. This writing method includes the following three: (1) To generate multiple laser beams that have different wavelengths from each other and include wavelengths corresponding to the absorption wavelength of the photothermal converter. (2) Shining the generated multiple laser beams onto the surface of the recording medium through a predetermined gap, and scanning the multiple laser beams on the surface of the recording medium in a synchronized manner in the same direction. (3) Scanning the surface of a recording medium with multiple laser beams, where multiple laser beam irradiation spots are arranged at predetermined intervals in a direction perpendicular to or diagonally intersecting the scanning direction of the multiple laser beams.

[0008] In a drawing method according to one embodiment of the present disclosure, multiple laser beams are scanned on the surface of a recording medium with multiple laser beam irradiation spots arranged at predetermined gaps in directions perpendicular to or diagonally intersecting the scanning direction of the multiple laser beams. This reduces thermal crosstalk between adjacent recording layers in the stacking direction. As a result, the possibility of unexpected writing or erasing can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example of a schematic configuration of a drawing system according to one embodiment of the present disclosure. [Figure 2] This figure shows an example of the schematic configuration of the drawing section in Figure 1. [Figure 3] This figure shows an example of the cross-sectional configuration of the recording medium in Figure 2. [Figure 4A] This figure shows the drawing process in the drawing system shown in Figure 1. [Figure 4B] This figure shows the drawing process in the drawing system shown in Figure 1. [Figure 5] This figure shows an example of a drawing method related to a comparative example. [Figure 6] This figure shows an example of a drawing method related to a comparative example. [Figure 7] This figure shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 8] This figure shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 9] This figure shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 10] This figure shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 11] This figure shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 12] Figures 1, 7-11 illustrate a modified example of the drawing method in the drawing system. [Figure 13]This shows an example of the drawing procedure in the drawing method shown in Figure 12. [Figure 14] This shows an example of the drawing procedure in the drawing method shown in Figure 12. [Figure 15] This shows an example of the drawing procedure in the drawing method shown in Figure 12. [Figure 16] This shows the evaluation results of images drawn using the drawing method shown in Figure 12. [Figure 17] This figure shows a modified example of the drawing method in Figure 12. [Modes for carrying out the invention]

[0010] The following describes in detail the forms for implementing this disclosure with reference to the drawings. The following description is one specific example of this disclosure, and this disclosure is not limited to the following forms.

[0011] <1. Embodiment> [composition] A drawing system 100 according to one embodiment of the present disclosure will be described. Figure 1 shows a schematic example of the drawing system 100 according to this embodiment. The drawing system 100 writes (draws) and erases information on the recording medium 10, which will be described later. For example, the drawing system 100 converts image data described in a device-dependent color space (hereinafter referred to as "input image data"), which is input from an external source, into image data described in the color space of the recording medium 10 (hereinafter referred to as "drawing image data"). Here, the device-dependent color space is, for example, an RGB color space such as sRGB or Adobe® RGB. The color space of the recording medium 10 is the color space that the recording medium 10 has as a characteristic. The drawing system 100 further converts the drawing image data obtained by the conversion into an output setting value of the drawing unit 150, which will be described later, and inputs the output setting value obtained by the conversion into the drawing unit 150 to perform drawing on the recording medium 10. Below, the drawing system 100 will be described first, and then the recording medium 10 will be described.

[0012] (Drawing system 100) The drawing system 100 includes, for example, a communication unit 110, an input unit 120, a display unit 130, a storage unit 140, a drawing unit 150, and an information processing unit 160. The drawing system 100 is connected to a network, for example, via the communication unit 110. The network is, for example, a communication line such as a LAN or WAN. Terminal devices are connected to the network, for example. The drawing system 100 is configured to communicate with terminal devices via the network. The terminal devices are, for example, mobile terminals, and are configured to communicate with the drawing system 100 via the network.

[0013] The communication unit 110 communicates with external devices such as terminal devices. The communication unit 110 transmits input image data received from an external device, such as a mobile terminal, to the information processing unit 160. The input image data is data in which the grayscale values ​​of each drawing coordinate are described in a device-dependent color space. In the input image data, the grayscale values ​​of each drawing coordinate are composed of, for example, 8-bit red grayscale values, 8-bit green grayscale values, and 8-bit blue grayscale values.

[0014] The input unit 120 receives input from the user (e.g., execution instructions, data input, etc.). The input unit 120 transmits the information entered by the user to the information processing unit 160. The display unit 130 displays the screen based on various screen data created by the information processing unit 160. The display unit 130 is composed of, for example, a liquid crystal panel or an organic EL (Electro-Luminescence) panel.

[0015] The memory unit 140 stores, for example, various programs. The memory unit 140 stores, for example, a program that converts input image data described in a device-dependent color space into drawing image data described in the color space of the recording medium 10. The drawing image data is, for example, data in which the gradation values ​​of each drawing coordinate are described in the color space of the recording medium 10. When the color space of the recording medium 10 is the Leuco color space, the gradation values ​​of each drawing coordinate in the drawing image data are composed of, for example, 8-bit magenta gradation values, 8-bit cyan gradation values, and 8-bit yellow gradation values. The memory unit 140 stores, for example, a program that derives output setting values ​​for the drawing unit 150 for each drawing coordinate based on the gradation values ​​of the drawing image data obtained by the conversion. In Figure 1, these programs are collectively represented as program 141.

[0016] The information processing unit 160 is configured to include, for example, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), and executes various programs (for example, program 141) stored in the memory unit 140. When program 141 is loaded, the information processing unit 160 executes a series of procedures described in program 141.

[0017] Next, the drawing unit 150 will be described. Figure 2 shows a schematic example of the drawing unit 150's configuration. The drawing unit 150 includes, for example, a signal processing circuit 51, a laser drive circuit 52, a light source unit 53, a scanner drive circuit 54, an X scanner unit 55, a Y stage drive circuit 56, and a Y stage 57. The drawing unit 150 performs drawing on the recording medium 10 by controlling the output of the light source unit 53 based on a voltage value file (list of command voltage values) input from the information processing unit 160.

[0018] The signal processing circuit 51 acquires a voltage value file (a list of command voltage values) input from the information processing unit 160 as an image signal Din. The signal processing circuit 51 generates a pixel signal Dout from the image signal Din, for example, according to the scanner operation of the X scanner unit 55. The pixel signal Dout causes the light source unit 53 (for example, each of the light sources 53A, 53B, and 53C described later) to output laser light with power corresponding to the command voltage value. The signal processing circuit 51, together with the laser drive circuit 52, controls the peak value of the current pulse applied to the light source unit 53 (for example, each of the light sources 53A, 53B, and 53C) according to the pixel signal Dout.

[0019] The laser driving circuit 52 drives each of the light sources 53A, 53B, and 53C of the light source unit 53 according to, for example, the pixel signal Dout. The laser driving circuit 52 controls the brightness (brightness / darkness) of the laser light to draw an image corresponding to the pixel signal Dout. The laser driving circuit 52 includes, for example, a driving circuit 52A that drives light source 53A, a driving circuit 52B that drives light source 53B, and a driving circuit 52C that drives light source 53C. The light sources 53A, 53B, and 53C perform drawing on the recording medium 10 by outputting laser light with power corresponding to the command voltage value to the recording medium 10. The light sources 53A, 53B, and 53C emit laser light in the near-infrared region. Light source 53A is, for example, a semiconductor laser that emits laser light La with an emission wavelength λ1. Light source 53B is, for example, a semiconductor laser that emits laser light Lb with an emission wavelength λ2. The light source 53C is, for example, a semiconductor laser that emits laser light Lc with an emission wavelength λ3.

[0020] The light source unit 53 has a plurality of light sources (for example, three light sources 53A, 53B, 53C) with different emission wavelengths in the near-infrared region. Each light source (for example, each light source 53A, 53B, 53C) generates laser light that includes a wavelength corresponding to the absorption wavelength of the photothermal conversion agent (described later) contained in the recording medium 10. The light source unit 53 further has an optical system that outputs multiple laser beams (for example, three laser beams La, Lb, Lc) emitted from the plurality of light sources (for example, three light sources 53A, 53B, 53C) in a predetermined direction with a predetermined gap between them. This optical system outputs the multiple laser beams La, Lb, Lc to the X scanner unit 55 such that multiple irradiation spots Pa, Pb, Pc generated on the recording medium 10 by the multiple laser beams La, Lb, Lc are aligned in the X-axis direction with a predetermined gap between them on the Y stage 57. The X-axis direction is perpendicular to the movement direction (Y-axis direction) of the Y-stage 57 and parallel to the scanning direction of the 1-axis scanner 55a, which will be described later. 53 Such an optical system includes, for example, two reflective mirrors 53a and 53d and two dichroic mirrors 53b and 53c.

[0021] The laser beams La and Lb emitted from the two light sources 53A and 53B are, for example, made nearly parallel (collimated) by a collimating lens. Then, for example, the laser beam La is reflected by the reflective mirror 53a and the dichroic mirror 53b, while the laser beam Lb passes through the dichroic mirror 53b. As a result, the laser beams La and Lb are output aligned in a predetermined direction. The laser beams La and Lb pass through the dichroic mirror 53c.

[0022] The laser light Lc emitted from the light source 53C is, for example, made into nearly parallel light (collimated light) by a collimating lens. Then, the laser light Lc is reflected by, for example, a reflective mirror 53d and a dichroic mirror 53c. As a result, the laser light La,Lb that has passed through the dichroic mirror 53c and the laser light Lc that has been reflected by the dichroic mirror 53c are output aligned in a predetermined direction. The light source unit 53 outputs the laser light La,Lb,Lc aligned in a predetermined direction by the optical system described above to the X scanner unit 55.

[0023] Here, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may overlap. In this case, the optical system is configured such that the optical axis of the laser beam La reflected by the dichroic mirror 53b and the optical axis of the laser beam Lb transmitted through the dichroic mirror 53b intersect at a predetermined angle. Alternatively, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may not completely overlap, but may be offset from each other. Alternatively, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may be separated from each other. In these cases, the optical system may be configured so that the optical axis of the laser beam La reflected by the dichroic mirror 53b and the optical axis of the laser beam Lb transmitted through the dichroic mirror 53b intersect at a predetermined angle, or they may be configured so that they are parallel to each other.

[0024] In the dichroic mirror 53c, the optical system is configured such that the spots transmitted by the laser light La or laser light Lb and the spots reflected by the laser light Lc do not completely overlap with each other, but are offset. In this case, in the dichroic mirror 53c, the spots transmitted by the laser light La, the spots transmitted by the laser light Lb, and the spots reflected by the laser light Lc may be aligned with a slight offset in a predetermined direction. In the dichroic mirror 53c, the spots transmitted by the laser light La, the spots transmitted by the laser light Lb, and the spots reflected by the laser light Lc may be aligned with a predetermined gap between them.

[0025] In these cases, the optical system may be configured such that the optical axis of the laser beam La transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lb transmitted through the dichroic mirror 53c, and the optical axis of the laser beam Lc reflected by the dichroic mirror 53c intersect each other at a predetermined angle. At this time, the light source unit 53 outputs multiple laser beams La, Lb, and Lc to the X scanner unit 55 with the optical axes of the multiple laser beams La, Lb, and Lc offset from each other, and also outputs multiple laser beams La, Lb, and Lc to the X scanner unit 55 such that the optical axes of the multiple laser beams La, Lb, and Lc intersect each other at a predetermined angle.

[0026] Alternatively, the optical system may be configured such that the optical axis of the laser beam La transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lb transmitted through the dichroic mirror 53c, and the optical axis of the laser beam Lc reflected by the dichroic mirror 53c are parallel to each other. In this case, the light source unit 53 outputs multiple laser beams La, Lb, and Lc to the X scanner unit 55 with their optical axes offset from each other, and also outputs multiple laser beams La, Lb, and Lc to the X scanner unit 55 such that their optical axes are parallel to each other with a predetermined gap between them.

[0027] The scanner drive circuit 54 drives the X scanner unit 55 based on a control signal input from, for example, the signal processing circuit 51. Furthermore, if, for example, the X scanner drive circuit 54 receives a signal from the X scanner unit 55 regarding the illumination angle of a single-axis scanner 55a (described later), it drives the X scanner unit 55 to achieve a desired illumination angle based on that signal.

[0028] The X-scanner unit 55 scans, for example, multiple laser beams La, Lb, and Lc incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10. The X-scanner unit 55 includes, for example, a 1-axis scanner 55a and an fθ lens 55b. The 1-axis scanner 55a is, for example, a galvanometer mirror that scans the laser beams La, Lb, and Lc incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10 based on a drive signal input from the scanner drive circuit 54. The fθ lens 55b converts the constant velocity rotational motion of the 1-axis scanner 55a into the constant velocity linear motion of a spot moving on the focal plane (the surface of the recording medium 10).

[0029] The Y-stage drive circuit 56 drives the Y-stage 57 based on a control signal input from, for example, the signal processing circuit 51. The Y-stage 57 moves the recording medium 10 placed on the Y-stage 57 in the Y-axis direction at a predetermined speed relative to the X-scanner unit 55 by displacing the Y-stage 57 in the Y-axis direction at a predetermined speed. Through the coordinated operation of the X-scanner unit 55 and the Y-stage 57, the laser beams La, Lb, and Lc raster scan the surface of the recording medium 10.

[0030] (Recording medium 10) Next, the recording medium 10 will be described.

[0031] Figure 3 shows an example of the configuration of each layer included in the recording medium 10. The recording medium 10 is, for example, a reversible recording medium that can write (draw) and erase information. The recording medium 10 may also be, for example, an irreversible recording medium that can only write (draw) information once and cannot be erased. The recording medium 10 comprises a plurality of recording layers 13, 15, and 17 with different color tones from each other. The recording medium 10 has a structure in which, for example, a base layer 12, a recording layer 13, a heat insulating layer 14, a recording layer 15, a heat insulating layer 16, a recording layer 17, and a protective layer 18 are stacked in this order on a substrate 11. The protective layer 18 is positioned opposite the substrate 11 via the base layer 12, the recording layer 13, the heat insulating layer 14, the recording layer 15, the heat insulating layer 16, and the recording layer 17. The protective layer 18 may be located on the outermost surface of the recording medium 10, or a layer other than the protective layer 18 may be located on the outermost surface of the recording medium 10.

[0032] The three recording layers 13, 15, and 17 are arranged in the order of recording layer 13, recording layer 15, and recording layer 17 from the substrate 11 side. The two heat insulating layers 14 and 16 are arranged in the order of heat insulating layer 114a and heat insulating layer 16 from the substrate 11 side. The base layer 12 is formed in contact with the surface of the substrate 11. The protective layer 18 is formed on the outermost surface of the recording medium 10.

[0033] The substrate 11 supports each recording layer 13, 15, 17 and each heat insulating layer 14, 16. The substrate 11 functions as a substrate for forming each layer on its surface. The substrate 11 may be light-transmitting or light-impermeable. If it is light-impermeable, the surface color of the substrate 11 may be, for example, white or a color other than white.

[0034] The base material 11 may be a card or a film. The base material 11 may have a design, picture, photograph, text, or a combination of two or more of these printed on one of its main surfaces on the side where the recording layer 13 is provided. The base material 11 may include, for example, plastic. The base material 11 may optionally contain at least one selected from the group consisting of colorants, antistatic agents, flame retardants, and surface modifiers.

[0035] The plastic used in the base material 11 includes, for example, at least one selected from the group consisting of ester resins, amide resins, olefin resins, vinyl resins, acrylic resins, imide resins, styrene resins, and engineering plastics. If the base material 11 contains two or more resins, these two or more resins may be mixed, copolymerized, or laminated.

[0036] The above ester resin includes, for example, at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. The above amide resin includes, for example, at least one selected from the group consisting of nylon 6, nylon 66, and nylon 610. The above olefin resin includes, for example, at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP). The above vinyl resin includes, for example, polyvinyl chloride (PVC).

[0037] The above acrylic resin includes, for example, at least one selected from the group consisting of polyacrylate, polymethacrylate, and polymethyl methacrylate (PMMA). The imide resin includes, for example, at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), and polyetherimide (PEI). The above styrene resin includes, for example, at least one selected from the group consisting of polystyrene (PS), high-impact polystyrene, acrylonitrile-styrene resin (AS resin), and acrylonitrile-butadiene-styrene resin (ABS resin). The above-mentioned engineering plastics include, for example, at least one selected from the group consisting of polycarbonate (PC), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyetherketone (PEK), polyether-etherketone (PEEK), polyphenylene oxide (PPO), and polyethersulfite.

[0038] The base layer 12 has the function of improving the adhesion between the recording layer 13 and the substrate 11. The base layer 12 is made of, for example, a light-transmitting material. A moisture-resistant barrier layer or a light-resistant barrier layer may be provided above or below the base layer 12 or the substrate 11. In addition, an insulating layer may be provided between the base layer 12 and the recording layer 13.

[0039] The three recording layers 13, 15, and 17 can, for example, reversibly change their state between a colored state and a decolorized state. The three recording layers 13, 15, and 17 may, for example, have irreversibility, meaning that once they change from a decolorized state to a colored state, they cannot return to a decolorized state. The three recording layers 13, 15, and 17 are configured such that the colors in the colored state are different from each other. Each of the three recording layers 13, 15, and 17 is composed of a color-developing compound, a photothermal converter, and a smear / decolorizer. The three recording layers 13, 15, and 17 are composed of different color-developing compounds and different photothermal converters. In the three recording layers 13, 15, and 17, the color-developing compound, the photothermal converter, and the smear / decolorizer are dispersed in a polymer material.

[0040] For example, leuco dyes are used as color-developing compounds. Leuco dyes become colored when heated by binding with a stimulating / dechromizing agent, or they become decolorized when separated from the stimulating / dechromizing agent. The color tones of the leuco dyes contained in each recording layer 13, 15, and 17 differ for each recording layer 13, 15, and 17. The leuco dye contained in recording layer 13 develops magenta color when heated by binding with a stimulating / dechromizing agent. The leuco dye contained in recording layer 15 develops cyan color when heated by binding with a stimulating / dechromizing agent. The leuco dye contained in recording layer 17 develops yellow color when heated by binding with a stimulating / dechromizing agent. The positional relationship of the three recording layers 13, 15, and 17 is not limited to the above example. Also, the three recording layers 13, 15, and 17 become transparent when decolorized. As a result, the recording medium 10 can record images using a wide color gamut.

[0041] The photothermal converter is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. In this specification, the near-infrared region refers to the wavelength range of 700 nm to 2500 nm. It is preferable to select a photothermal converter that has a narrow light absorption band in the near-infrared region and whose light absorption bands do not overlap with each other in the recording layers 13, 15, and 17.

[0042] The thermal insulation layer 14 is designed to reduce heat transfer between the recording layer 13 and the recording layer 15. The thermal insulation layer 16 is designed to reduce heat transfer between the recording layer 15 and the recording layer 17. The protective layer 18 is designed to protect the surface of the recording medium 10 and functions as an overcoat layer for the recording medium 10. The thermal insulation layers 14, 16 and the protective layer 18 are made of transparent material. The recording medium 10 may, for example, have a relatively rigid resin layer (e.g., a PEN resin layer) directly beneath the protective layer 18. The protective layer 18 may also include a moisture-resistant barrier layer or a light-resistant barrier layer. Furthermore, the protective layer 18 may include any functional layer.

[0043] Examples of leuco dyes include existing dyes for thermal paper. Specifically, one example is the compound shown in Chemical Formula 1 below, which contains, for example, an electron-donating group in its molecule. [ka]

[0044] There are no particular restrictions on the color-developing compounds, and they can be appropriately selected depending on the purpose. Specific examples of color-developing compounds include, in addition to the compounds shown in Formula 1 above, fluorane compounds, triphenylmethanephthalide compounds, azaphthalide compounds, phenothiazine compounds, leucoauramine compounds, and indolinophthalide compounds. In addition, for example, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-di(n-butylamino)fluorane, 2-anilino-3-methyl-6-(Nn-propyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isopropyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isobutyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(Nn-amyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-sec-butyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(Nn-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-( N-iso-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-(Nn-propyl-N-isopropylamino)fluorane, 2-anilino-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-anilino-3-methyl-6-(N-methyl-p-toluidino)fluorane, 2-(m-trichloromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trifluoromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trichloromethylanilino)-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-(2,4-dimethylanilino)-3-methyl-6-diethylaminofluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-ethylanilino)fluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-propyl-p-toluidino)fluorane, 2-anilino-6-(Nn-hexyl-N-ethylamino)fluorane, 2-(o-chloroanilino)-6-diethylaminofluorane, 2-(o-chloroanilino)-6-dibutylaminofluorane, 2-(m-trifluoromethylanilino)-6-diethylaminofluorane, 2,3-dimethyl-6-dimethylaminofluorane, 3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-chloro-6 -Diethylaminofluorane, 2-bromo-6-diethylaminofluorane, 2-chloro-6-dipropylaminofluorane, 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2-chloro-6-(N-ethyl-N-isoamylamino)fluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-(o-chloroanilino)-3-chloro-6-cyclohexylaminofluorane, 2-(m-trifluoromethylanilino)-3-chloro-6-diethylaminofluorane, 2-(2,3-dichloroanilino)-3-chloro-6-diethylaminofluorane, 1,2-Benzo-6-diethylaminofluorane, 3-diethylamino-6-(m-trifluoromethylanilino)fluorane, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 3-(1-octyl- 2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide, 3-(1-ethyl-2-methylin Dol-3-yl)-3-(4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(4-Nn-amyl-N-methylaminophenyl)-4-azaphthalide, 3-(1-methyl-2-methylindole-3-yl)-3-(2-hexyloxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl) Phenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 2-(p-acetylanilino)-6-(Nn-amyl-Nn-butylamino)fluorane, 2-benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-benzylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-benzylamino-6-(N-ethyl-2,4-dimethylanilino)fluorane, 2-benzylamino-6-(N-methyl-p-toluidino)fluorane, 2-benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-(di-p-methylbenzylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-(α-phenylethylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-methylamino-6-(N-methylanilino)fluorane, 2-methylamino-6-(N-ethylanilino)fluorane, 2-methylamino-6-(N-propylanilino)fluorane , 2-ethylamino-6-(N-methyl-p-toluidino)fluorane, 2-methylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-ethylamino-6-(N-ethyl-2,4-dimethylanilino)fluorane, 2-dimethylamino-6-(N-methylanilino)fluorane, 2-dimethylamino-6-(N-ethylanilino)fluorane, 2-diethylamino-6-(N-methyl-p-toluidino)fluorane, 2-diethylamino-6-(N-ethyl-p-toluidino)fluorane, 2-dipropylamino-6-(N-methyl Fluoranilino)fluoran, 2-dipropylamino-6-(N-ethylanilino)fluoran, 2-amino-6-(N-methylanilino)fluoran, 2-amino-6-(N-ethylanilino)fluoran, 2-amino-6-(N-propylanilino)fluoran, 2-amino-6-(N-methyl-p-toluidino)fluoran, 2-amino-6-(N-ethyl-p-toluidino)fluoran, 2-amino-6-(N-propyl-p-toluidino)fluoran, 2-amino-6-(N-methyl-p-ethylanilino)fluoran, 2-amino-6-(N-ethylanilino)fluoran (Tyl-p-ethylanilino)fluoran, 2-amino-6-(N-propyl-p-ethylanilino)fluoran, 2-amino-6-(N-methyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-ethyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-propyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-methyl-p-chloroanilino)fluoran, 2-amino-6-(N-ethyl-p-chloroanilino)fluoran, 2-amino-6-(N-propyl-p-chloroanilino)fluoran, 1,Examples include 2-benzo-6-(N-ethyl-N-isoamylamino)fluorane, 1,2-benzo-6-dibutylaminofluorane, 1,2-benzo-6-(N-methyl-N-cyclohexylamino)fluorane, and 1,2-benzo-6-(N-ethyl-N-toluidino)fluorane. In the recording layers 13, 15, and 17, one of the above compounds may be used alone as a color-forming compound, or two or more thereof may be used in combination.,

[0045] The color developing / decolorizing agent is used, for example, for developing color of a colorless color-forming compound or decolorizing a color-forming compound that exhibits a predetermined color. Examples of the color developing / decolorizing agent include phenol derivatives, salicylic acid derivatives, and urea derivatives. Specifically, the color developing / decolorizing agent may contain, for example, a compound represented by the following Chemical Formula 2.

Chemical Formula

[0046] The color developing agent may contain, for example, a compound represented by the following Chemical Formula 3.

Chemical Formula

[0047] When formulas 2 and 3 contain hydrocarbon groups, these hydrocarbon groups are a general term for groups composed of carbon (C) and hydrogen (H), and may be saturated hydrocarbon groups or unsaturated hydrocarbon groups. Saturated hydrocarbon groups are aliphatic hydrocarbon groups that do not have multiple carbon-carbon bonds, while unsaturated hydrocarbon groups are aliphatic hydrocarbon groups that have multiple carbon-carbon bonds (carbon-carbon double bonds or carbon-carbon triple bonds).

[0048] If chemical formulas 2 and 3 contain a hydrocarbon group, the hydrocarbon group may be in the form of a chain or may contain one or more rings. The chain may be a straight chain or a branched chain having one or more side chains, etc.

[0049] (X containing one benzene ring) 0 , X 1 ) X in chemical formula 2 0 and X in formula 3 1 This is, for example, a divalent group containing one benzene ring. This divalent group is represented, for example, by the following chemical formula 4. [ka] (However, in Chemical Formula 4, X 21 It can be there or not, X 21 If X 21 X is a divalent group. 22 It can be there or not, X 22 If X 22 R is a divalent group. 21 is a single-valued base. n21 is an integer from 0 to 4. If n21 is an integer from 2 to 4, then R 21These elements may be identical or different. (* indicates a connection point.)

[0050] In chemical formula 4, X relative to the benzene ring 21 and X 22 The bonding position of X is not limited. That is, X relative to the benzene ring. 21 and X 22 The bond position may be the ortho, meta, or para position.

[0051] The above divalent group containing one benzene ring is preferably represented by the following chemical formula 5 from the viewpoint of improving high-temperature and high-humidity storage characteristics. [ka] (However, in chemical formula 5, R 22 is a single-valued base. n²² is an integer from 0 to 4. If n²² is an integer from 2 to 4, then R 22 These elements may be identical or different. (* indicates a connection point.)

[0052] X in chemical formula 2 0 If is a divalent group containing one benzene ring, then in chemical formula 5, Z relative to the benzene ring. 01 and Z 02 The bonding position is not limited. That is, Z relative to the benzene ring. 01 and Z 02 The bond position may be the ortho, meta, or para position.

[0053] X in Chemical Formula 3 1 If is a divalent group containing one benzene ring, then in chemical formula 5, Z relative to the benzene ring. 11 and Z 12 The bonding position is not limited. That is, Z relative to the benzene ring. 11 and Z 12 The bond position may be the ortho, meta, or para position.

[0054] (X 21 , X 22) X in Chemical Formula 4 21 , X 22 Each of these groups can be a divalent group and is not particularly limited, but examples include hydrocarbon groups which may have substituents. The hydrocarbon groups are preferably in chain form, and normal alkyl chains are particularly preferred.

[0055] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0056] X in Chemical Formula 4 21 , X 22 When the normal alkyl group is a normal alkyl group, the number of carbon atoms in the normal alkyl group is preferably 8 or less, more preferably 6 or less, even more preferably 5 or less, and particularly preferably 3 or less, from the viewpoint of high-temperature storage stability. When the number of carbon atoms in the normal alkyl group is 8 or less, the length of the normal alkyl group is short, so thermal disturbance is less likely to occur in the color developer during high-temperature storage, and the site that interacted with the color-developing compound such as leuco dye during color development is less likely to detach. Therefore, the color-developing compound such as leuco dye is less likely to lose its color during high-temperature storage, thus improving high-temperature storage stability.

[0057] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0058] (R 21 ) R in Chemical Formula 4 21 This can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have substituents.

[0059] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0060] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0061] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0062] (R 22 ) R in Chemical Formula 5 22 R in Chemical Formula 2 can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. 21 It is similar to that.

[0063] (X containing two benzene rings) 0 , X 1 ) X in chemical formula 2 0 and X in formula 3 1 This is, for example, a divalent group containing two benzene rings. This divalent group is represented, for example, by the following chemical formula 6. [ka] (However, in chemical formula 6, X 31 It can be there or not, X 31 If X 31 X is a divalent group. 32 It can be there or not, X 32 If X 32 X is a divalent group. 33 It can be there or not, X 33 If X33 R is a divalent group. 31 , R 32 n31 and n32 are independent single-valued bases. n31 and n32 are independent integers from 0 to 4. If n31 is an integer from 2 to 4, then R 31 They may be the same or different. If n32 is an integer between 2 and 4, then R 32 These elements may be identical or different. (* indicates a connection point.)

[0064] In chemical formula 6, X relative to the benzene ring 31 and X 32 The bonding position of X is not limited. That is, X relative to the benzene ring. 31 and X 32 The bond position may be the ortho, meta, or para position. Similarly, in chemical formula 6, X on the benzene ring 32 and X 33 The bonding position of X is not limited. That is, X relative to the benzene ring. 32 and X 33 The bond position may be the ortho, meta, or para position.

[0065] The above divalent group containing two benzene rings is preferably represented by the following chemical formula 7 from the viewpoint of improving high-temperature and high-humidity storage characteristics. [ka] (However, in chemical formula 7, X 34 It is a divalent group. 33 , R 34 n33 and n34 are each independent and unvalued bases. n33 and n34 are each independent integers from 0 to 4. If n33 is an integer from 2 to 4, then R 33 They may be the same or different. If n34 is an integer between 2 and 4, then R 34 These elements may be identical or different. (* indicates a connection point.)

[0066] X in Chemical Formula 2 0 is a divalent group containing two benzene rings, the bonding positions of Z 01 and X 34 with respect to the benzene ring in Chemical Formula 7 are not limited. That is, the bonding position of Z 01 and X 34 with respect to the benzene ring may be any of an ortho position, a meta position, and a para position. Similarly, in Chemical Formula 7, the bonding positions of Z 02 and X 34 with respect to the benzene ring are not limited. That is, the bonding position of Z 02 and X 34 with respect to the benzene ring may be any of an ortho position, a meta position, and a para position.

[0067] X in Chemical Formula 3 1 is a divalent group containing two benzene rings, the bonding positions of Z 11 and X 34 with respect to the benzene ring in Chemical Formula 7 are not limited. That is, the bonding position of Z 11 and X 34 with respect to the benzene ring may be any of an ortho position, a meta position, and a para position. Similarly, in Chemical Formula 7, the bonding positions of Z 12 and X 34 with respect to the benzene ring are not limited. That is, the bonding position of Z 12 and X 34 with respect to the benzene ring may be any of an ortho position, a meta position, and a para position.

[0068] (X 31 , X 32 , X 33 ) X in Chemical Formula 6 31 , X 32 , X 33 are each independently a divalent group, and are not particularly limited; for example, they are each a hydrocarbon group optionally having a substituent. Said hydrocarbon group is the same as X 21 , X 22 in Chemical Formula 4 above.

[0069] (X 34 ) X in Chemical Formula 7 34 X can be any divalent group and is not particularly limited, but an example is a hydrocarbon group which may have substituents. The hydrocarbon group is X in the above chemical formula 4. 21 , X 22 It is similar to that.

[0070] (R 31 , R 32 ) R in chemical formula 6 31 , R 32 R can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are R in the above formula 4, respectively. 21 It is similar to that.

[0071] (R 33 , R 34 ) R in Chemical Formula 7 33 , R 34 R can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are R in the above formula 4, respectively. 21 It is similar to that.

[0072] (Y 01 , Y 02 ) Y in Chemical Formula 2 01 , Y 02 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group (-X), a carboxyl group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent.

[0073] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0074] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0075] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0076] In chemical formula 2, (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 It is preferable that one of them is a hydroxyl group (-OH). (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 One of these groups is a hydroxyl group (-OH), which improves label quality and lightfastness.

[0077] (Y 11 , Y 12 , Y 13 , Y 14 ) In chemical formula 3, Y relative to the benzene ring 11 and Y 12 The bonding position is not limited. That is, Y relative to the benzene ring. 11 and Y 12 The bond position of can be any of the ortho, meta, or para positions. Similarly, in chemical formula 3, Y on the benzene ring 13 and Y 14 The bonding position is not limited. That is, Y relative to the benzene ring. 13 and Y 14 The bond position may be any of the ortho, meta, or para positions. In chemical formula 3, Y is attached to one of the benzene rings. 11 and Y 12 The bond position of and Y relative to the other benzene 13and Y 14 The bonding position may be the same as or different from that position.

[0078] Y in Chemical Formula 3 11 , Y 12 , Y 13 , Y 14 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group, a carboxyl group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are Y in the above chemical formula 2, respectively. 01 , Y 02 It is similar to that.

[0079] In chemical formula 3, Y 11 and / or Y 13 It is preferable that it is a hydroxyl group (-OH). 11 and / or Y 13 The presence of a hydroxyl group (-OH) improves both label quality and lightfastness.

[0080] (Z 01 , Z 02 ) Z in Chemical Formula 2 01 , Z 02 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 01 , Z 02 It is preferable that it is a urea bond. 01 If it is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 02 If the bond is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0081] (Z 11 , Z 12 ) Z in Chemical 3 11 , Z 12 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 11 , Z 12 It is preferable that it is a urea bond. 11 If it is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 12 If the bond is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0082] Other color-reducing agents include, for example, 4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis(o-methylphenol), 4,4'-secondarybutylidenebisphenol, 4,4'-isopropylidenebis(2-tert-butylphenol), p-zinc nitrobenzoate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, 2,2-(3,4'-dihydroxydiphenyl)propane, bis(4-hydroxy-3-methylphenyl)sulfide, 4-{β-( p-Methoxyphenoxy)ethoxy}salicylic acid, 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane, 1,5-bis(4-hydroxyphenithio)-5-oxapentane, monobenzyl phthalate monocalcium salt, 4,4'-cyclohexyllidenediphenol, 4,4'-isopropylidenebis(2-chlorophenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-2-methyl)phenol, 1,1,3-tris(2-methyl (4-hydroxy-5-tert-butylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 4,4'-thiobis(6-tert-butyl-2-methyl)phenol, 4,4'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone (4-hydroxy-4'-isopropoxydiphenylsulfone), 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, p-hydroxybenzoate isopropyl, p-hydroxy Benzyl thiobenzoate, benzyl protocatechate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis(4-hydroxyphenylthio)-propane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, methyl bis(4-hydroxyphenyl)acetate, benzyl bis(4-hydroxyphenyl)acetate, 1,3-bis(4-hydroxycumyl)benzene, 1,4-bis(4-hydroxycumyl)benzene, 2,4'-diphenolsulfone, 2,2'-diallyl-4,4'-Diphenolsulfone, 3,4-Dihydroxyphenyl-4'-Methyldiphenylsulfone, Zinc 1-Acetyloxy-2-Naphthoate, Zinc 2-Acetyloxy-1-Naphthoate, Zinc 2-Acetyloxy-3-Naphthoate, α,α-Bis(4-Hydroxyphenyl)-α-Methyltoluene, Antipyrine complex of zinc thiocyanate, Tetrabromobisphenol A, Tetrabromobisphenol S, 4,4'-Thiobis(2-Methylphenol), 4,4'-Thiobis(2-Chlorophenol), Dodecylphosphonic acid, Tetradecylphosphonic acid, Hexadecylphosphonic acid, Octadecylphosphonic acid, Eicosylphosphonic acid, Docosylphosphonic acid, Tetracosylphosphonic acid, Hexacosylphosphonic acid, Octacosylphosphonic acid, α-Hydroxydodecylphosphonic acid Examples include hydroxytetradecylphosphonic acid, α-hydroxyhexadecylphosphonic acid, α-hydroxyoctadecylphosphonic acid, α-hydroxyeicosylphosphonic acid, α-hydroxydocosylphosphonic acid, α-hydroxytetracosylphosphonic acid, dihexadecyl phosphate, dioctadecyl phosphate, dieicosyl phosphate, didocosyl phosphate, monohexadecyl phosphate, monooctadecyl phosphate, monoeicosyl phosphate, monodocosyl phosphate, methylhexadecyl phosphate, methyloctadecyl phosphate, methyleicosyl phosphate, methyldocosyl phosphate, amylhexadecyl phosphate, octylhexadecyl phosphate, and laurylhexadecyl phosphate. For recording layers 13, 15, and 17, one of the above compounds may be used alone as a developer / color reducer, or two or more may be used in combination. ,

[0083] A photothermal converter is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. Preferably, the photothermal converter uses a near-infrared absorbing dye that has an absorption peak in the wavelength range of 700 nm to 2500 nm and has almost no absorption in the visible region. Specifically, examples include compounds having a phthalocyanine skeleton (phthalocyanine dyes), compounds having a naphthalocyanine skeleton (naphthalocyanine dyes), compounds having a squarylium skeleton (squarylium dyes), metal complexes such as dithio complexes, diimonium salts, aminium salts, and inorganic compounds. Examples of inorganic compounds include graphite, carbon black, metal powder particles, metal oxides such as cobalt tetroxide, iron oxide, chromium oxide, copper oxide, titanium black, and ITO, metal nitrides such as niobium nitride, metal carbides such as tantalum carbide, metal sulfides, or various magnetic powders. In addition, compounds having a cyanine skeleton with excellent light resistance and heat resistance (cyanine dyes) may also be used.

[0084] Excellent light resistance means that the material does not decompose when irradiated with a laser. Excellent heat resistance means that, for example, when the material is formed in a film with a polymer material and stored at, for example, 150°C for 30 minutes, the maximum absorption peak value of the absorption spectrum does not change by more than 20%. Examples of compounds having such a cyanine skeleton include those having at least one of the following counterions in the molecule: SbF6, PF6, BF4, ClO4, CF3SO3, and (CF3SO3)2N, and a methine chain containing a 5-membered ring or a 6-membered ring.

[0085] Cyanine dyes preferably possess both one of the above-mentioned counterions and cyclic structures such as five-membered and six-membered rings within the methine chain, but sufficient light resistance and heat resistance are ensured if at least one of them is present. Materials with excellent light resistance and heat resistance do not decompose when irradiated with a laser, as described above. One way to confirm light resistance is to measure the change in the absorption spectrum peaks during a xenon lamp irradiation test. If the rate of change after 30 minutes of irradiation is 20% or less, the light resistance can be judged to be good. One way to confirm heat resistance is to measure the change in the absorption spectrum peaks when stored at 150°C. If the rate of change after a 30-minute test is 20% or less, the heat resistance can be judged to be good.

[0086] The polymer material is preferably one in which the color-developing compound, smear / decolorizing agent, and photothermal converter can be homogeneously dispersed. Furthermore, the polymer material is preferably highly transparent in order to obtain high visibility of the information written on the recording layer 11, and is preferably highly soluble in organic solvents, for example. Examples of polymer materials include thermosetting resins and thermoplastic resins. Specifically, examples include polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylcellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polycarbonate, polyacrylic acid ester, polymethacrylate ester, acrylic acid copolymer, maleic acid polymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethylcellulose, carboxymethylcellulose, and starch.

[0087] The recording layers 13, 15, and 17 are composed of at least one of the above-mentioned color-developing compound, stimulating / dechromizing agent, and photothermal converter. Preferably, the color-developing compound and stimulating / dechromizing agent contained in the recording layers 13, 15, and 17 are in a ratio of color-developing compound:stimulating / dechromizing agent = 1:2 (by weight). The amount of photothermal converter varies depending on the film thickness of the recording layers 13, 15, and 17. In addition to the above-mentioned materials, the recording layers 13, 15, and 17 may also be composed of various additives such as sensitizers and ultraviolet absorbers.

[0088] The protective layer 18 may have the function of suppressing the ingress of moisture, oxygen, or both into the recording layers 13, 15, and 17. The protective layer 18 covers the surface of the recording layer 17. The protective layer 18 has a density of, for example, 0.001 g / m². 2 / day or more 10g / m 2 It is preferable that the protective layer 18 has a water vapor transmission rate of less than or equal to 1 / day. Furthermore, similar to the polymer material constituting the recording layers 13, 15, and 17, it is preferable that the protective layer 18 has high transparency in order to obtain high visibility of the information written on the recording layers 13, 15, and 17. An example of such a protective layer 18 is a laminated film in which an inorganic oxide film is provided on a substrate made of a plastic film. In a protective layer 18 configured as a laminated film of a plastic film and an inorganic oxide film, for example, the inorganic oxide film covers the recording layer 17 on the side (inside) of the recording layer 17 and the plastic film on the outside.

[0089] The base plastic film can be, for example, an industrial plastic film, and can be formed using at least one of polyethylene terephthalate (PET), polycarbonate (PC), and methyl methacrylate (PMMA). The thickness of the plastic film is preferably, for example, 5 μm to 100 μm.

[0090] Examples of inorganic oxide films include silicon oxide films (SiO2) deposited using methods such as sputtering and chemical vapor deposition (CVD). x (film), aluminum oxide film (AlO x (film) and silicon nitride film (SiN x Examples include a single layer or multilayer film using at least one of the films. The thickness of the protective layer 18 is preferably, for example, 10 nm or more and 1 μm or less.

[0091] Next, an example of writing information in the drawing system 100 according to this embodiment will be described.

[0092] [write] First, the user prepares an uncolored recording medium 10 and places it on the Y stage 57. Next, the user transmits input image data, described in the RGB color space, to the drawing system 100 via the network from a terminal device. When the drawing system 100 receives the input image data via the network, it executes the following drawing process.

[0093] First, when the information processing unit 160 receives input image data via the communication unit 110, it converts the input image data, which is described in the RGB color space, into leuco image data, which is described in the leuco color space. Next, the information processing unit 160 derives a voltage value file (a list of command voltage values) based on the gradation values ​​of each color at each drawing coordinate of the leuco image data obtained by the conversion. The information processing unit 160 then transmits the derived voltage value file (a list of command voltage values) to the drawing unit 150.

[0094] The signal processing circuit 51 of the drawing unit 60 acquires a voltage value file (list of command voltage values) input from the information processing unit 160 as an image signal Din. From the image signal Din, the signal processing circuit 51 generates an image signal synchronized with the scanner operation of the X scanner unit 55, according to the characteristics of the laser light, such as the wavelength. The signal processing circuit 51 generates a projected image signal such that the laser light is emitted according to the generated image signal. The signal processing circuit 51 outputs the generated projected image signal to the laser drive circuit 52 of the drawing unit 150.

[0095] The laser driving circuit 52 drives each of the light sources 53A, 53B, and 53C of the light source unit 53 according to the projection image signal corresponding to each wavelength. At this time, the laser driving circuit 52 emits laser light from at least one of the light sources 53A, 53B, and 53C and scans it on the recording medium 10.

[0096] For example, to colorize the recording layer 17, a laser beam La with an emission wavelength λ1 is irradiated onto the recording layer 17 with an energy sufficient to reach the color-developing temperature. This causes the photothermal converter contained in the recording layer 17 to generate heat, and a color reaction occurs between the color-developing compound and the symmetric / dechromizing agent, resulting in the irradiated area becoming yellow, for example. Similarly, to colorize the recording layer 15, a laser beam Lb with an emission wavelength λ2 is irradiated onto the recording layer 15 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area becoming cyan, for example. To color the recording layer 13, a laser beam Lc with an emission wavelength λ3 is irradiated onto the recording layer 13 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area becoming cyan, for example. In this way, by irradiating any part with laser light of the corresponding wavelength, it becomes possible to record patterns, etc. (for example, full-color patterns, etc.).

[0097] Figure 4 illustrates the process of writing information to the recording medium 10 by the drawing unit 150. Figure 4 shows an example of the cross-sectional configuration of the recording medium 10, and further illustrates how the laser beams La, Lb, and Lc are scanned from left to right across the paper through predetermined gaps ΔX1 and ΔX2.

[0098] In this embodiment, the mechanism consisting of a scanner drive circuit 54, an X scanner unit 55, a Y stage drive circuit 56, and a Y stage 57 functions as a scanning unit that irradiates the surface of the recording medium 10 with multiple laser beams La, Lb, and Lc generated by the light source unit 53 through predetermined gaps ΔX1 and ΔX2. This mechanism further scans the surface of the recording medium 10 with the multiple laser beams La, Lb, and Lc in the same direction as each other. This mechanism scans the surface of the recording medium 10 with multiple irradiation spots Pa, Pb, and Pc from the multiple laser beams La, Lb, and Lc aligned with predetermined gaps ΔX1 and ΔX2 in the same direction as the scanning direction (X axis direction) of the multiple laser beams La, Lb, and Lc.

[0099] Preferably, the gap ΔX1 between the laser beam La irradiation spot Pa and the laser beam Lb irradiation spot Pb is such that the high-temperature region Ra generated in and around the recording layer 13 by the laser beam La and the high-temperature region Rb generated in and around the recording layer 15 by the laser beam Lb do not overlap with each other. Furthermore, preferably, the gap ΔX2 between the laser beam Lb irradiation spot Pb and the laser beam Lc irradiation spot Pc is such that the high-temperature region Rb generated in and around the recording layer 15 by the laser beam Lb and the high-temperature region Rc generated in and around the recording layer 17 by the laser beam Lc do not overlap with each other.

[0100] The scanning order of the multiple laser beams La, Lb, and Lc on the surface of the recording medium 10 may be, for example, as shown in Figure 4, an order that allows for the color development of the recording layers 13, 15, and 17 starting from the layer closest to the outermost surface of the recording medium 10. Alternatively, the scanning order of the multiple laser beams La, Lb, and Lc on the surface of the recording medium 10 may be, for example, an order that allows for the color development of the recording layers 13, 15, and 17 starting from the layer closest to the substrate 11 (the layer furthest from the outermost surface of the recording medium 10).

[0101] [effect] Next, the effects of the drawing system 100 according to this embodiment will be explained in comparison with the comparative example. Figures 5 and 6 show the process of writing information to the recording medium 10 in the comparative example.

[0102] In the comparative example shown in Figure 5, the laser beams La, Lb, and Lc irradiate the same spot P1 (same pixel) on the recording medium 10. As a result, the high-temperature region Ra and the high-temperature region Rb partially overlap with each other, and the high-temperature region Rb and the high-temperature region Rc partially overlap with each other. Consequently, in the comparative example shown in Figure 5, thermal crosstalk occurs between two adjacent recording layers in the stacking direction, leading to unexpected writing and erasing. Therefore, the comparative example shown in Figure 5 has the problem of poor drawing quality.

[0103] In the comparative example shown in Figure 6, the entire recording medium 10 is sequentially irradiated with laser beams La, Lb, and Lc. As a result, the high-temperature regions Ra and Rb do not overlap with each other, nor do the high-temperature regions Rb and Rc overlap with each other. Therefore, the drawing quality is good in the comparative example shown in Figure 6. However, the drawing time is three times longer compared to the comparative example shown in Figure 5.

[0104] On the other hand, in this embodiment, multiple laser beams La, Lb, and Lc generated by the light source unit 53 are irradiated onto the surface of the recording medium 10 through predetermined gaps ΔX1 and ΔX2, and the multiple laser beams La, Lb, and Lc are scanned synchronously in the same direction on the surface of the recording medium 10. This reduces thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction. As a result, the possibility of unexpected writing or erasing can be reduced.

[0105] Furthermore, in this embodiment, the irradiation spots Pa, Pb, and Pc are aligned with predetermined gaps ΔX1 and ΔX2 in the same direction as the scanning direction (X-axis direction) of the multiple laser beams La, Lb, and Lc, and the multiple laser beams La, Lb, and Lc are scanned on the surface of the recording medium 10. This reduces thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction. As a result, the possibility of unexpected writing or erasing can be reduced.

[0106] Furthermore, this embodiment includes a mechanism for scanning multiple laser beams La, Lb, and Lc in the X-axis direction, and a Y-stage 47 for moving the recording medium 10 in the Y-axis direction. This makes it possible to achieve raster scanning while reducing thermal crosstalk.

[0107] Furthermore, in this embodiment, raster scanning is performed by scanning multiple laser beams La, Lb, and Lc in the X-axis direction and moving the Y-stage 47 in the Y-axis direction. This makes it possible to achieve raster scanning while reducing thermal crosstalk.

[0108] Furthermore, in this embodiment, multiple laser beams La, Lb, and Lc are output to the X scanner unit 55 with their optical axes offset from each other. As a result, multiple laser beams La, Lb, and Lc are irradiated onto the surface of the recording medium 10 through predetermined gaps ΔX1 and ΔX2, thereby reducing thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction. Consequently, the possibility of unexpected writing or erasing can be reduced.

[0109] Furthermore, in this embodiment, multiple laser beams La, Lb, and Lc are output to the X scanner unit 55 such that the optical axes of the multiple laser beams La, Lb, and Lc are parallel to each other through predetermined gaps ΔX1 and ΔX2. As a result, since the multiple laser beams La, Lb, and Lc are irradiated onto the surface of the recording medium 10 through predetermined gaps ΔX1 and ΔX2, thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction, can be reduced. Consequently, the possibility of unexpected writing or erasing can be reduced.

[0110] Furthermore, in this embodiment, multiple laser beams La, Lb, and Lc are output to the X scanner unit 55 such that the optical axes of the multiple laser beams La, Lb, and Lc intersect each other at predetermined angles. As a result, the multiple laser beams La, Lb, and Lc are irradiated onto the surface of the recording medium 10 through predetermined gaps ΔX1 and ΔX2, thereby reducing thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction. Consequently, the possibility of unexpected writing or erasing can be reduced.

[0111] <2. Variant> The following describes a modified version of the drawing system 100 according to one embodiment of the present disclosure.

[0112] [Differentiation A] Figure 7 shows a modified example of the schematic configuration of the drawing system 100 according to the above embodiment. In the above embodiment, raster scanning was achieved by scanning laser beams La, Lb, and Lc in the X-axis direction with the X scanner unit 55 and moving the Y stage 57 in the Y-axis direction. However, in the above embodiment, raster scanning may also be achieved by using an XY scanner drive circuit 54A, an XY scanner unit 55A, and a fixed stage 57A instead of the scanner drive circuit 54, X scanner unit 55, Y stage drive circuit 56, and Y stage 57, as shown in Figure 7.

[0113] The XY scanner drive circuit 54A drives the XY scanner unit 55A based on a control signal input from, for example, the signal processing circuit 51. Furthermore, if, for example, the XY scanner drive circuit 54A receives a signal from the XY scanner unit 55A regarding the illumination angle of a two-axis scanner 55c (described later), it drives the XY scanner unit 55A to achieve a desired illumination angle based on that signal.

[0114] The XY scanner unit 55A, for example, scans the laser light La, Lb, Lc incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10, and moves the scan line in the Y-axis direction by a predetermined step width. The XY scanner unit 55A includes, for example, a two-axis scanner 55c and an fθ lens 55b. The two-axis scanner 55c is a galvanometer mirror that scans the laser light La, Lb, Lc incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10 based on a drive signal input from the XY scanner drive circuit 54A, and moves the scan line in the Y-axis direction by a predetermined step width. The fθ lens 55b converts the constant velocity rotational motion of the two-axis scanner 55c into the constant velocity linear motion of a spot moving on the focal plane (the surface of the recording medium 10). The fixed stage 57A is simply a stand that supports the recording medium 10.

[0115] In this modified example, an XY scanner unit 55A is provided that scans multiple laser beams La, Lb, and Lc in the X-axis direction and moves the scan lines of the multiple laser beams La, Lb, and Lc in the Y-axis direction with a predetermined step width. This makes it possible to achieve raster scanning while reducing thermal crosstalk.

[0116] Furthermore, in this embodiment, with the recording medium 10 stationary, a raster scan is performed by scanning multiple laser beams La, Lb, and Lc in the X-axis direction and moving the scan lines of the multiple laser beams La, Lb, and Lc in the Y-axis direction with a predetermined step width. This makes it possible to achieve a raster scan while reducing thermal crosstalk.

[0117] [Variation B] Figure 8 shows a modified example of the schematic configuration of the drawing system 100 according to the above embodiment. In the above embodiment, raster scanning was achieved by scanning laser beams La, Lb, and Lc in the X-axis direction with the X scanner unit 55 and moving the Y stage 57 in the Y-axis direction. However, in the above embodiment, raster scanning may also be achieved by using a light source unit 53D instead of a light source unit 53, and using an XY stage drive circuit 56A and an XY stage 57B instead of a scanner drive circuit 54, an X scanner unit 55, a Y stage drive circuit 56, and a Y stage 57, as shown in Figure 8.

[0118] The light source unit 53D is equivalent to the light source unit 53 further equipped with a focusing lens 53e that focuses the laser beams La, Lb, and Lc. The XY stage drive circuit 56A drives the XY stage 57B based on a control signal input from, for example, the signal processing circuit 51. The XY stage 57B moves in the X-axis direction at a predetermined speed and in the Y-axis direction in predetermined step widths. The operation of the XY stage 57B causes the laser beams La, Lb, and Lc to raster scan the surface of the recording medium 10.

[0119] In this modified version, an XY stage 57B is provided that scans multiple laser beams La, Lb, and Lc in the X-axis direction and moves the scan lines of the multiple laser beams La, Lb, and Lc in the Y-axis direction with a predetermined step width. This makes it possible to achieve raster scanning while reducing thermal crosstalk.

[0120] [Differentiation C] Figure 9 shows a modified example of the schematic configuration of the drawing system 100 according to the above embodiment. In the above embodiment, an optical system including a dichroic mirror 53b was used to output laser beams La, Lb, and Lc aligned in a predetermined direction with a predetermined gap between them. However, in the above embodiment, the laser beams La, Lb, and Lc may be output aligned in a predetermined direction with a predetermined gap between them by using a light source unit 53E instead of the light source unit 53.

[0121] The light source unit 53E includes, for example, three light sources 53A, 53B, and 53C, three optical fibers 53f, 53g, and 53h, a fiber holder 53i, and a focusing lens 53j, as shown in Figure 9.

[0122] Optical fiber 53f is connected to light source 53A and propagates laser light La emitted from light source 53A. Optical fiber 53g is connected to light source 53B and propagates laser light Lb emitted from light source 53B. Optical fiber 53h is connected to light source 53C and propagates laser light Lc emitted from light source 53C. Fiber holder 53i holds the tips of the three optical fibers 53f, 53g, and 53h aligned in a predetermined direction. Focusing lens 53j focuses the laser light La, Lb, and Lc emitted from the tips of the three optical fibers 53f, 53g, and 53h. The laser light La, Lb, and Lc focused by focusing lens 53j are output to X scanner unit 55.

[0123] In this modified example, multiple laser beams La, Lb, and Lc are output to the X scanner unit 55 via optical fibers 53f, 53g, and 53h, each provided separately for each laser beam. As a result, multiple laser beams La, Lb, and Lc are irradiated onto the surface of the recording medium 10 through predetermined gaps ΔX1 and ΔX2, thereby reducing thermal crosstalk between adjacent recording layers 13 and 15 in the stacking direction, and between adjacent recording layers 15 and 17 in the stacking direction. Consequently, the possibility of unexpected writing or erasing can be reduced.

[0124] [Differentiation D] Figure 10 shows a modified example of the schematic configuration of the drawing system 100 according to Modification A described above. In Modification A, an optical system including a dichroic mirror 53b was used to output laser beams La, Lb, and Lc aligned in a predetermined direction with a predetermined gap between them. However, in Modification A, the laser beams La, Lb, and Lc may also be output aligned in a predetermined direction with a predetermined gap between them by using a light source unit 53E instead of the light source unit 53. Even in this case, raster scanning can be achieved while reducing thermal crosstalk.

[0125] [Differentiation Example E] Figure 11 shows a modified example of the schematic configuration of the drawing system 100 according to the modified example B described above. In modified example B, an optical system including a dichroic mirror 53b was used to output laser beams La, Lb, and Lc aligned in a predetermined direction with a predetermined gap between them. However, in modified example B, the laser beams La, Lb, and Lc may also be output aligned in a predetermined direction with a predetermined gap between them by using a light source unit 53F instead of the light source unit 53. The light source unit 53F, for example, as shown in Figure 11, has three light sources 53A, 53B, and 53C, three optical fibers 53f, 53g, and 53h, a fiber holder 53i, and a focusing lens 53e. Even in this case, raster scanning can be achieved while reducing thermal crosstalk.

[0126] [Modification F] Figure 12 shows one modified example of the drawing method in the drawing system 100 according to the above embodiment and its modified example. In the above embodiment and its modified example, the laser beams La, Lb, and Lc were scanned in a direction parallel to the X-axis direction with a predetermined gap between them. However, for example, as shown in Figure 12, the laser beams La, Lb, and Lc may be scanned in the X-axis direction with a predetermined gap between them in a direction perpendicular to the X-axis direction (Y-axis direction). In this case, a mechanism capable of performing such a scan scans the multiple laser beams La, Lb, and Lc on the surface of the recording medium 10 with multiple irradiation spots Pa, Pb, and Pc from multiple laser beams La, Lb, and Lc arranged with a predetermined gap between them in a direction perpendicular to the scanning direction of the multiple laser beams La, Lb, and Lc (X-axis direction) (Y-axis direction).

[0127] In this modified example, the light source unit 53 has an optical system that outputs multiple laser beams (e.g., three laser beams La, Lb, Lc) emitted from multiple light sources (e.g., three light sources 53A, 53B, 53C) arranged in the Y-axis direction with a predetermined gap between them. This optical system outputs multiple laser beams La, Lb, Lc to the X scanner unit 55 such that multiple irradiation spots Pa, Pb, Pc are arranged in the order Pa, Pb, Pc on the Y-stage 57 with a predetermined gap between them in the Y-axis direction.

[0128] Here, the illumination spot Pa moves along line L1 corresponding to a certain row of pixels in the recording medium 10. The illumination spot Pa moves along line L1 corresponding to a certain row of pixels in the recording medium 10. The illumination spot Pb moves along line L2 corresponding to a row of pixels located at a predetermined distance from the row of pixels to which the illumination spot Pa is moving in the recording medium 10. The illumination spot Pc moves along line L3 corresponding to a row of pixels located at a predetermined distance from the row of pixels to which the illumination spot Pb is moving in the recording medium 10.

[0129] Figures 13, 14, and 15 show an example of the drawing procedure in the drawing system 100 according to this modified example.

[0130] The writing system 100 first irradiates the recording medium 10 with laser light La and scans the irradiation spot Pa in the X-axis direction. Then, when the scanning of one line of the irradiation spot Pa is complete, the writing system 100 temporarily stops the irradiation of laser light La and moves the Y stage 47 in the Y-axis direction, thereby moving the recording medium 10 by a predetermined distance in the Y-axis direction. Subsequently, the writing system 100 irradiates the recording medium 10 with laser light La at a location a predetermined distance away from the line scanned immediately before, and scans the irradiation spot Pa in the X-axis direction. In this way, the writing system 100 performs multiple scans of the recording medium 10 in the X-axis direction with laser light La (see Figure 13). At this time, a portion of the recording layer 13 of the recording medium 10 is colored with a predetermined color (Color A) by irradiation with laser light La.

[0131] Next, the writing system 100 irradiates the recording medium 10 with laser beams La and Lb, and scans the irradiated spots Pa and Pb in the X-axis direction. At this time, the writing system 100 irradiates the lines on the recording medium 10 that have been scanned with laser beam La with laser beam Lb, and scans the irradiated spot Pb in the X-axis direction. Then, when the scanning of one line of the irradiated spots Pa and Pb is completed, the writing system 100 temporarily stops the irradiation of laser beams La and Pb and moves the Y-stage 47 in the Y-axis direction, thereby moving the recording medium 10 by a predetermined distance in the Y-axis direction.

[0132] Next, the drawing system 100 irradiates laser beams La and Lb at a predetermined distance from the line scanned immediately before, and scans the irradiated spots Pa and Pb in the X-axis direction. At this time as well, the drawing system 100 irradiates the line on the recording medium 10 that has been scanned with laser beam La with laser beam Lb, and scans the irradiated spot Pb in the X-axis direction. In this way, the drawing system 100 performs X-axis scanning of the recording medium 10 with laser beams La and Lb multiple times (see Figure 14).

[0133] At this time, in the recording medium 10, a portion of the recording layer 13 is colored with a predetermined color (Color A) by irradiation with laser light La, and furthermore, a portion of the recording layer 15 is colored with a predetermined color (Color B) by irradiation with laser light Lb. In the recording medium 10, areas where both the recording layers 13 and 15 are colored when viewed from the stacking direction are colored with a composite color of Color A and Color B.

[0134] Next, the writing system 100 irradiates the recording medium 10 with laser beams La, Lb, and Lc, scanning the irradiated spots Pa, Pb, and Pc in the X-axis direction. At this time, the writing system 100 irradiates the line on the recording medium 10 that has been scanned with laser beam La with laser beam Lb, scanning the irradiated spot Pb in the X-axis direction. Furthermore, the writing system 100 irradiates the line on the recording medium 10 that has been scanned with laser beam Lc, scanning the irradiated spot Pc in the X-axis direction. Then, when the scanning of one line of irradiated spots Pa, Pb, and Pc is completed, the writing system 100 temporarily stops the irradiation of laser beams La, Pb, and Lc, and moves the Y-stage 47 in the Y-axis direction, thereby moving the recording medium 10 by a predetermined distance in the Y-axis direction.

[0135] Next, the writing system 100 irradiates the recording medium 10 with laser beams La, Lb, and Lc at a predetermined distance from the line scanned immediately before, and scans the irradiated spots Pa, Pb, and Pc in the X-axis direction. At this time, the writing system 100 also irradiates the recording medium 10 with laser beam Lb onto the line scanned with laser beam La, and scans the irradiated spot Pb in the X-axis direction. Furthermore, the writing system 100 irradiates the recording medium 10 with laser beam Lc onto the line scanned with laser beam Lb, and scans the irradiated spot Pc in the X-axis direction. In this way, the writing system 100 performs X-axis scanning of the recording medium 10 multiple times with laser beams La, Lb, and Lc (see Figure 15).

[0136] At this time, in the recording medium 10, a portion of the recording layer 13 is colored with a predetermined color (Color A) by irradiation with laser light La, a portion of the recording layer 15 is colored with a predetermined color (Color B) by irradiation with laser light Lb, and a portion of the recording layer 17 is colored with a predetermined color (Color C) by irradiation with laser light Lc. In the recording medium 10, the areas where both the recording layers 13, 15, and 17 are colored when viewed from the stacking direction are colored with a composite color of Color A, Color B, and Color C (for example, BLACK).

[0137] Incidentally, the distance Δy1 between irradiation spot Pa and irradiation spot Pb is set such that, for example, the period from when laser light La is irradiated onto a predetermined pixel in the recording medium 10 until when laser light Lb is irradiated (cooling period Δt1 at the predetermined pixel) is 0.2 seconds or more. Also, the distance Δy2 between irradiation spot Pb and irradiation spot Pc is set such that, for example, the period from when laser light Lb is irradiated onto a predetermined pixel in the recording medium 10 until when laser light Lc is irradiated (cooling period Δt2 at the predetermined pixel) is 0.2 seconds or more. Distances Δy1 and Δy2 may be equal to each other or may be different from each other. Cooling periods Δt1 and Δt2 may be equal to each other or may be different from each other.

[0138] When focusing on a predetermined pixel in the recording medium 10, the timing of irradiation with laser light La, laser light Lb, and laser light Lc to that pixel are different from each other. As a result, cooling periods Δt1 and Δt2 are provided for each pixel in the recording medium 10. Since the cooling periods Δt1 and Δt2 are 0.2 seconds or longer, as described above, each pixel can be sufficiently cooled before the next laser irradiation can be performed. As a result, thermal crosstalk that occurs in the comparative example shown in Figure 5 can be prevented, and good rendering quality can be obtained. Note that the cooling periods Δt1 and Δt2 do not necessarily have to be 0.2 seconds or longer, and can be set according to the required rendering quality.

[0139] Figure 16 shows the experimental results for the comparative example shown in Figure 5 and for several examples in this modified example where various distances Δy1 and Δy2 were set. In Figure 16, ΔE_avg represents the average value of the color difference ΔE* for each example compared to the comparative example when a black image is drawn on the recording medium 10. In Figure 16, the judgment represents the result of determining whether the average value of the color difference ΔE* is less than or equal to the upper limit of the Class B tolerance of 6.5. If the average value of the color difference ΔE* is less than or equal to the upper limit of the Class B tolerance of 6.5, the judgment is ○ (pass). On the other hand, if the average value of the color difference ΔE* exceeds the upper limit of the Class B tolerance of 6.5, the judgment is × (fail). In Figure 16, takt represents the time required to draw a black image on the recording medium 10. In Figure 16, takt is expressed as a value based on the takt of the comparative example. Figure 16 shows that in Examples 6 to 11, the result was ○ (pass), and in Examples 1 to 11, the cycle time was 1 / 3 of that of the comparative example.

[0140] In this modified example, raster scanning may be achieved by using an XY scanner drive circuit 54A, an XY scanner unit 55A, and a fixed stage 57A instead of the scanner drive circuit 54, the X scanner unit 55, the Y stage drive circuit 56, and the Y stage 57.

[0141] [Differentiation G] Figure 17 shows one modified example of the drawing method in the drawing system 100 according to the modified example F described above. In modified example F, the laser beams La, Lb, and Lc were scanned in the X-axis direction with predetermined gaps between them in a direction perpendicular to the X-axis direction (Y-axis direction). However, as shown in Figure 17, for example, the laser beams La, Lb, and Lc may be scanned in the X-axis direction with predetermined gaps between them in a direction that diagonally intersects both the X-axis and Y-axis directions. In other words, the irradiation spots Pa, Pb, and Pc do not have to be aligned in a straight line parallel to the Y-axis, and the irradiation spots Pb and Pc may be offset from the irradiation spot Pa not only in the X-axis direction but also in the Y-axis direction. In this case, a mechanism capable of performing such a scan scans the surface of the recording medium 10 with multiple irradiation spots Pa, Pb, and Pc from multiple laser beams La, Lb, and Lc, all aligned with predetermined gaps in a direction that diagonally intersects both the X-axis and Y-axis directions.

[0142] In this modified example, the light source unit 53 has an optical system that outputs multiple laser beams (e.g., three laser beams La, Lb, Lc) emitted from multiple light sources (e.g., three light sources 53A, 53B, 53C) arranged in a direction that diagonally intersects both the X-axis and Y-axis directions, with a predetermined gap between them. This optical system outputs multiple laser beams La, Lb, Lc to the X scanner unit 55 such that multiple irradiation spots Pa, Pb, Pc are arranged in the order of Pa, Pb, Pc on the Y stage 57 with a predetermined gap between them, in a direction that diagonally intersects both the X-axis and Y-axis directions. Even in this case, as with the modified example F described above, thermal crosstalk that occurs in the comparative example shown in Figure 5 can be prevented, and good drawing quality can be obtained.

[0143] In this modified example, the arrangement of the irradiation spots Pa, Pb, and Pc does not have to be in a straight line, and the amount of deviation of the irradiation spots Pa, Pb, and Pc with respect to a line segment parallel to the Y axis may be set to an arbitrary size. In this case, the scanning mechanism in the drawing system 100 may scan multiple laser beams La, Lb, and Lc on the surface of the recording medium 10 in a state where the lines being scanned by each laser beam La, Lb, and Lc do not overlap with each other (i.e., multiple laser beams La, Lb, and Lc do not scan the same line). Even in this case, as with the modified example F described above, thermal crosstalk that occurs in the comparative example shown in Figure 5 can be prevented, and good drawing quality can be obtained.

[0144] In this modified example, raster scanning may be achieved by using an XY scanner drive circuit 54A, an XY scanner unit 55A, and a fixed stage 57A instead of the scanner drive circuit 54, the X scanner unit 55, the Y stage drive circuit 56, and the Y stage 57.

[0145] In the above embodiment and its modified form, the laser driving circuit 52 may, for example, pulse-drive each of the light sources 53A, 53B, and 53C of the light source unit 53, or it may drive them continuously while scanning one line. When the laser driving circuit 52 continuously drives each of the light sources 53A, 53B, and 53C, depending on the color to be expressed, it may also reduce the power of at least one of the light sources 53A, 53B, and 53C to zero.

[0146] The effects described herein are illustrative only. The effects of this disclosure are not limited to those described herein. This disclosure may have effects other than those described herein.

[0147] Furthermore, for example, this disclosure can take the following form. (1) A writing system for writing on a recording medium in which multiple recording layers, each composed of different color-producing compounds and different photothermal converters, are stacked via an insulating layer, A light source unit that generates multiple laser beams having different wavelengths from each other and including wavelengths corresponding to the absorption wavelength of the photothermal conversion agent, A scanning unit irradiates the surface of the recording medium with a plurality of laser beams generated by the light source unit through a predetermined gap, and scans the plurality of laser beams on the surface of the recording medium in a synchronized manner in the same direction. Equipped with, The scanning unit scans the surface of the recording medium with the multiple laser beams, with the irradiation spots of the multiple laser beams arranged at predetermined intervals in a direction perpendicular to or diagonally intersecting the scanning direction of the multiple laser beams. A drawing system. (2) The scanning unit scans the recording medium with a second laser beam, which is different from the first laser beam, in the line where scanning has been performed with the first laser beam among the plurality of laser beams. (1) The drawing system described above. (3) The scanning unit includes an optical system for scanning the plurality of laser beams in a first direction, and a stage for moving the recording medium in a second direction perpendicular to the first direction. The drawing system described in (1) or (2). (4) The scanning unit has an optical system that scans the plurality of laser beams in a first direction and moves the scan lines of the plurality of laser beams in a second direction perpendicular to the first direction by a predetermined step width. The drawing system described in (1) or (2). (5) The light source unit outputs the plurality of laser beams to the scanning unit with the optical axes of the plurality of laser beams offset from each other. A drawing system as described in any one of (1) through (4). (6) The light source unit outputs the plurality of laser beams to the scanning unit such that the optical axes of the plurality of laser beams are parallel to each other with a predetermined gap between them. (5) The drawing system described above. (7) The light source unit outputs the plurality of laser beams to the scanning unit such that the optical axes of the plurality of laser beams intersect each other at a predetermined angle. (5) The drawing system described above. (8) The light source unit outputs the plurality of laser beams to the scanning unit via optical fibers provided separately for each laser beam. (5) The drawing system described above. (9) A drawing method for drawing on a recording medium in which multiple recording layers, each composed of different color-producing compounds and different photothermal converters, are stacked with an insulating layer in between, The process involves generating multiple laser beams that have different wavelengths from each other and include wavelengths corresponding to the absorption wavelength of the photothermal converter, The generated multiple laser beams are irradiated onto the surface of the recording medium through a predetermined gap, and the multiple laser beams are scanned synchronously in the same direction on the surface of the recording medium. The plurality of laser beams are arranged at predetermined intervals, with the irradiation spots of the plurality of laser beams aligned in a direction perpendicular to or diagonally intersecting the scanning direction of the plurality of laser beams, and the plurality of laser beams are scanned on the surface of the recording medium. including How to draw. (10) In the recording medium, scanning is performed with a second laser beam, which is different from the first laser beam, on a line where scanning has been performed with the first laser beam among the plurality of laser beams. including The drawing method described in (9). (11) This includes performing a raster scan by scanning the plurality of laser beams in a first direction and moving the recording medium in a second direction perpendicular to the first direction. The drawing method described in (9). (12) The method includes performing a raster scan by scanning the plurality of laser beams in a first direction while the recording medium is stationary, and moving the scan lines of the plurality of laser beams in a second direction perpendicular to the first direction by a predetermined step width. The drawing method described in (9).

[0148] This application claims priority based on Japanese Patent Application No. 2021-061778, filed with the Japan Patent Office on March 31, 2021, and all contents of that application are incorporated herein by reference.

[0149] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A writing system for writing on a recording medium in which multiple heat-sensitive recording layers, each composed of a different color-developing compound and a different photothermal converter, are stacked with an insulating layer in between, A light source unit that generates multiple laser beams having different wavelengths from each other and including wavelengths corresponding to the absorption wavelength of the photothermal conversion agent, A scanning unit irradiates the surface of the recording medium with a predetermined gap between multiple laser beams generated by the light source unit, and scans the surface of the recording medium with the multiple laser beams synchronized in the same direction; Equipped with, The scanning unit scans the surface of the recording medium with the multiple laser beams, with the irradiation spots of the multiple laser beams arranged at predetermined intervals in a direction perpendicular to or diagonally intersecting the scanning direction of the multiple laser beams. The scanning unit includes an optical system that performs scanning with the plurality of laser beams in a first direction, and moves the scanning lines of the plurality of laser beams in a second direction perpendicular to the first direction by a predetermined step width. A drawing system.

2. The scanning unit scans the recording medium with a second laser beam, which is different from the first laser beam, in the line where the first laser beam among the plurality of laser beams has been scanned by the optical system. The drawing system according to claim 1.

3. The scanning unit performs scanning with the plurality of laser beams using the optical system while the recording medium is stationary. The drawing system according to claim 1.

4. The light source unit outputs the plurality of laser beams to the optical system with the optical axes of the plurality of laser beams offset from each other. The drawing system according to claim 1.

5. The light source unit outputs the plurality of laser beams to the optical system such that the optical axes of the plurality of laser beams are parallel to each other with a predetermined gap between them. The drawing system according to claim 4.

6. The light source unit outputs the plurality of laser beams to the optical system such that the optical axes of the plurality of laser beams intersect each other at a predetermined angle. The drawing system according to claim 4.

7. The light source unit outputs the plurality of laser beams to the optical system via optical fibers provided separately for each laser beam. The drawing system according to claim 4.

8. The optical system is shared for each of the plurality of laser beams. The drawing system according to claim 4.

9. A drawing method for drawing on a recording medium in which multiple heat-sensitive recording layers, each composed of a different color-developing compound and a different photothermal converter, are stacked with an insulating layer in between, The process involves generating multiple laser beams that have different wavelengths from each other and include wavelengths corresponding to the absorption wavelength of the photothermal converter, The generated multiple laser beams are irradiated onto the surface of the recording medium through a predetermined gap, and the multiple laser beams are scanned on the surface of the recording medium in a synchronized manner in the same direction. The plurality of laser beams are scanned on the surface of the recording medium with the irradiation spots of the plurality of laser beams arranged at predetermined intervals in a direction perpendicular to or diagonally intersecting the scanning direction of the plurality of laser beams, The optical system performs scanning with the plurality of laser beams in a first direction, and moves the scanning lines of the plurality of laser beams in a second direction perpendicular to the first direction by a predetermined step width. including How to draw.

10. The optical system scans a line on the recording medium that has been scanned by a first laser beam from among the plurality of laser beams, and scans a second laser beam that is different from the first laser beam from among the plurality of laser beams. including The drawing method according to claim 9.

11. With the recording medium stationary, the optical system performs scanning with the plurality of laser beams. including The drawing method according to claim 9.

12. By sharing the optical system for each of the multiple laser beams, the multiple laser beams are scanned with their optical axes offset from one another. including The drawing method according to claim 9.

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