JP2023141354A - Recording medium - Google Patents

Abstract

To provide a recording medium in which, while expanding the range of wavelength selection system for recording light and simplifying the device configuration, the effects of variations in the oscillation wavelength of recording light (including temperature variation, etc.) is reduced to achieve stable image recording.SOLUTION: A recording medium of an embodiment contains multiple photothermal conversion materials each having an absorption spectrum with a different absorption peak, and includes a heat-sensitive coloring layer in which the composite absorption spectrum of multiple photothermal conversion materials is the absorption spectrum.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to recording media.

Conventionally, recording media used in multicolor laser recording systems have been designed to generate color by placing a photothermal conversion material that absorbs specific wavelengths and generates heat near the coloring layer, and irradiating it with laser light as recording light. Ta.

This makes it possible to perform multicolor recording by using multiple types of photothermal conversion materials that absorb different wavelengths for each color to be produced, and by selecting the wavelength of the laser light used as the recording light to match the absorption wavelength. It had been.

Japanese Patent Application Publication No. 2005-138558 Patent No. 3509246 Patent No. 4411394

Therefore, the wavelength of laser light as recording light is determined by the recording medium used, and the range of wavelength selectivity of recording light is narrow.
Furthermore, due to changes in the ambient temperature or the temperature of the laser light source itself, the recording light is greatly affected by variations in the oscillation wavelength of the recording light, resulting in unstable color development and the possibility that stable image recording may not be possible.

The present invention has been made in view of the above, and reduces the influence of variations in the oscillation wavelength of the recording light (including temperature changes, etc.) while simplifying the device configuration by expanding the range of wavelength selection of the recording light. The object of the present invention is to provide a recording medium on which stable image recording can be performed.

In order to solve the above problems, the recording medium of the embodiment includes a thermosensitive coloring layer that includes a plurality of photothermal conversion materials each having an absorption spectrum with a different absorption peak, and whose absorption spectrum is a composite absorption spectrum of the plurality of photothermal conversion materials. Be prepared.

FIG. 1 is an external front view of a recording medium according to an embodiment in a state where information is recorded. FIG. 2 is a partially cross-sectional perspective view of the recording medium. FIG. 3 is an explanatory diagram of an example of the light absorption characteristics of the photothermal conversion material. FIG. 4 is an explanatory diagram of the principle structure of the photothermal conversion material. FIG. 5 is a schematic block diagram of the image recording apparatus according to the embodiment.

Next, embodiments will be described with reference to the drawings.
First, the recording medium of the embodiment will be described.
[1] First Embodiment FIG. 1 is an external front view of a recording medium according to an embodiment in a state where information is recorded.

The recording medium MD on which information has been recorded can be roughly divided into a full-color image forming area ARC for recording a full-color image such as an ID photo, and an image forming area adjacent to the periphery of the full-color image forming area ARC. , a monochrome image forming area ARM in which specific information such as issue date is recorded in monochrome.

In FIG. 1, in the recording medium MD, there are areas other than the full-color image forming area ARC and the monochrome image forming area ARM, but all other areas except the full-color image forming area ARC are treated as the monochrome image forming area ARM. Good too.

Further, in FIG. 1, the full-color image forming area ARC and the monochrome image forming area ARM are arranged so as to be in contact with each other, but they may be arranged separately, or one or both may be arranged in plurality. good.

Next, the configuration of the recording medium MD will be explained.
FIG. 2 is a partially cross-sectional perspective view of the recording medium.
FIG. 2 shows a state in which the recording medium MD is irradiated with laser light, and reference numeral 32 is a condensing lens that condenses the laser light in an image recording apparatus to be described later.
As shown in FIG. 2, the recording medium MD includes a base material 101, a first coloring layer 102, a first intermediate layer 103, a second coloring layer 104, a second intermediate layer 105, a third coloring layer 106, and a protective layer. 107 are formed in this order.

Here, the first coloring layer 102 functions as a thermosensitive coloring layer, and a first photothermal conversion material 108 for coloring cyan (C) is dispersed (mixed) in the first coloring layer 102. ing.
Similarly, the second coloring layer 104 functions as a thermosensitive coloring layer, and a second photothermal conversion material 109 for coloring magenta (M) is dispersed (mixed) in the second coloring layer 104. There is.
The third coloring layer 106 functions as a thermosensitive coloring layer, and a third photothermal conversion material 110 for producing yellow (Y) coloring is dispersed (mixed) in the third coloring layer 106.

In the above configuration, the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 are not a single material but a mixed material in which a plurality of photothermal conversion materials are mixed as described later. .

Further, the first intermediate layer 103 and the second intermediate layer 105 function as a heat insulating layer that adjusts the amount of heat transfer and suppresses heat transfer.

Further, the base material 101 holds a first coloring layer 102, a first intermediate layer 103, a second coloring layer 104, a second intermediate layer 105, a third coloring layer 106, and a protective layer 107.

In the above configuration, the thickness of the base material 101 is, for example, 100 μm, and the thermal conductivity ratio thereof is 0.01 to 5.00 W/m/K.

The first coloring layer 102, the second coloring layer 104, and the third coloring layer 106 are not irradiated with light, and the first photothermal conversion material 108, the second photothermal conversion material 109, or the third photothermal conversion material 110 performs photothermal conversion. In the initial state where no heat is applied and no heat is applied, it is colorless and transparent.

However, when light is irradiated and the first photothermal conversion material 108, second photothermal conversion material 109, or third photothermal conversion material 110 is performing photothermal conversion, color develops due to the addition of heat.
In this embodiment, the first coloring layer 102 is colored cyan by heat at a temperature equal to or higher than the low temperature threshold t1.

Further, the second coloring layer 104 is colored magenta by heat having a temperature equal to or higher than the intermediate temperature threshold t2.
Furthermore, the third coloring layer 106 develops a yellow color due to heat at a temperature equal to or higher than the high temperature threshold t3.
Here, low temperature threshold t1<medium temperature threshold t2<high temperature threshold t3.

Furthermore, the thickness of the first coloring layer 102, the second coloring layer 104, and the third coloring layer 106 is, for example, 1 to 50 μm, respectively, and the thermal conductivity ratio thereof is 0.01 to 50 W/m/K. Ru.

The first intermediate layer 103 is a layer that provides a thermal barrier during color development of the second coloring layer 104 and suppresses heat transfer from the second coloring layer 104 side to the first coloring layer 102 .
Here, the thickness of the first intermediate layer 103 is, for example, 7 to 100 μm, and the thermal conductivity ratio thereof is 0.01 to 50 W/m/K.

The second intermediate layer 105 is a layer that provides a thermal barrier during color development of the third coloring layer 106 and suppresses heat transfer from the third coloring layer 106 side to the second coloring layer 104 and the first coloring layer 102. .
Here, the thickness of the second intermediate layer 105 is, for example, 7 to 100 μm, and the thermal conductivity ratio thereof is 0.01 to 50 W/m/K.

The protective layer 107 is a layer provided to protect the first coloring layer 102, the first intermediate layer 103, the second coloring layer 104, the second intermediate layer 105, and the third coloring layer 106.
Here, the thickness of the protective layer 107 is, for example, 0.5 to 10 μm, and the thermal conductivity ratio thereof is 0.01 to 1 W/m/K.

Next, the light absorption characteristics of the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 will be explained in detail.

FIG. 3 is an explanatory diagram of an example of the light absorption characteristics of the photothermal conversion material.
As shown in FIG. 3, the first photothermal conversion material 108 is located on the shortest wavelength side among the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110, as shown in the absorption spectrum SPY. It has light absorption characteristics with an absorption peak PK1.

Further, as shown in the absorption spectrum SPC, the third photothermal conversion material 110 has an absorption peak PK3 on the longest wavelength side among the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110. It has light absorption properties.

The second photothermal conversion material 109 has a wavelength between the absorption peak PK1 of the first photothermal conversion material 108 and the absorption peak PK3 of the third photothermal conversion material 110, as shown in the absorption spectrum SPM. , has light absorption characteristics having an absorption peak PK2.

Therefore, the wavelength of the laser light emitted from the laser diode LD corresponding to the optical fiber FBY (yellow) is the wavelength corresponding to the absorption peak PK3, and the wavelength of the laser light emitted from the laser diode LD corresponding to the optical fiber FBM (magenta) is determined to be the wavelength corresponding to the absorption peak PK3. The wavelength of the laser beam emitted from the laser diode LD corresponding to the optical fiber FBC (cyan) is the wavelength corresponding to the absorption peak PK1.

In this case, as shown in FIG. 4, the absorption rates are flat in the vicinity of the absorption peaks PK1, PK2, and PK3 because of the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 108. This is because each of the photothermal conversion materials 110 is composed of, for example, a mixture of a plurality of photothermal conversion materials having similar absorption peaks.

Here, the structure of the photothermal conversion material will be explained in more detail.
In this case, the principles of construction of the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 are the same, so the first photothermal conversion material 108 will be described as an example.

FIG. 4 is an explanatory diagram of the principle structure of the photothermal conversion material.
As shown in FIG. 4A, the absorption spectrum of the first photothermal conversion material 108 is configured as a composite absorption spectrum of absorption spectra of five types of photothermal conversion materials having absorption peaks PK11 to PK15, for example.

That is, the composite absorption spectrum of the absorption spectra of the five types of photothermal conversion materials having absorption peaks PK11 to PK15 is expressed as the absorption spectrum SPY of the absorption peak PK1, as shown in FIG. 4(B).

By adopting such a configuration, the region with high absorption rate can be made to be close to flat as a whole instead of the peaks PK11 to PK15, and the temperature change during operation of the laser diode LD itself, the influence of the surrounding environment temperature, etc. That is, it is possible to stably record an image with a desired density by reducing the influence of fluctuations in the center wavelength of the recording light.

Next, an image recording apparatus according to an embodiment will be described.
FIG. 5 is a schematic block diagram of the image recording apparatus according to the embodiment.
The image recording device 10 includes a calculation section 11 that receives image data GD and performs various calculations for image recording, and a position control section 12 that controls the recording position on the recording medium MD based on the calculation results of the calculation section 11. Based on the calculation results of the calculation unit 11, the light source unit 13 including a plurality of (three in the example of FIG. 5) laser diodes LD and each laser in the light source unit 13 are installed at each recording position of the recording medium MD. An output control section 14 that controls the output of the diode LD, a fiber section 15 that includes a plurality of optical fibers FBY, FBM, and FBC that transmit laser light as recording light emitted from each laser diode LD; a recording head section 16 that records an image by emitting a laser beam transmitted through the recording head section 16; and a holding drive section 17 that holds the recording medium MD and drives it in the XY direction under the control of the position control section 12. It is equipped with.

Here, the multiple laser diodes LD function as multiple laser light sources.
Furthermore, the calculation section 11, the position control section 12, and the output control section 14 cooperate to select a plurality of laser diodes LD, which are laser light sources, and a holding drive section 17, which is a drive section, based on the input image data GD. It functions as a control unit that controls the

In the above configuration, the recording head section 16 includes a fiber housing 31 that holds a plurality of (three in FIG. 5) optical fibers FBY, FBM, and FBC, and condenses recording light emitted from the optical fibers FBY, FBM, and FBC. A casing 33 is provided for holding the fiber housing 31 and the condensing lens 32 in a predetermined position.

The holding drive unit 17 includes a stage 41 for placing and holding the recording medium MD in a predetermined position, an X-direction table 42 for guiding the stage 41 in the X direction, and an X-direction table under the control of the position control unit 12. 42; a Y-direction table 44 that guides the stage 41 in the Y-direction; and a Y-direction drive motor 45 that drives the Y-direction table 44 under the control of the position control unit 12. There is.

Here, the optical fiber FB and the condensing lens 32 function as light guide members, and the optical fiber FBY corresponds to yellow, the optical fiber FB corresponds to magenta, and the optical fiber FBC corresponds to magenta. , cyan, and three optical fibers FBY, FBM, and FBC work as a set to realize multicolor recording.
In the example of FIG. 5, the optical fibers FBY, FBM, and FBC are arranged to be separated by a plurality of pixels (for example, three pixels).

Here, the distance between the optical fibers FBY, FBM, and FBC, that is, the distance between the recording positions, is generally a position that is m (m is an integer) times the distance between pixels. However, when recording on the same pixel using adjacent optical fibers, the time interval (cooling time) and physical interval are set so as not to be influenced by the previous image recording (especially heat). This is to provide a.

Next, the materials constituting each layer will be explained.
First, the base material 101 will be explained.
The base material 101 includes polyester resin, polyethylene terephthalate (PET), glycol-modified polyester (PET-G), polypropylene (PP), polycarbonate (PP), and polychloride, which are generally used as card, paper, and film materials. It is possible to use resins that can be processed into film or plate shapes, such as vinyl (PVC), styrene-butadiene copolymer (SBR), polyacrylic resin, polyurethane resin, and polystyrene resin.

Furthermore, it is also possible to use a resin as the base material 101 by adding filler such as silica, titanium oxide, calcium carbonate, alumina, etc. to the above-mentioned resin to have whiteness, surface smoothness, heat insulation, etc.

For example, in addition to these, paper and resin materials described in Japanese Patent No. 3889431, Japanese Patent No. 4215817, Japanese Patent No. 4329744, Japanese Patent No. 4391286, etc. can be used.

Specifically, polyethylene terephthalate (A-PET, PETG), polycyclohexane 1,4-dimethyl phthalate (PCT), polystyrene (PS), polymethyl methacrylate (PMMA), transparent ABS (MABS), polypropylene (PP) , polyethylene (PE), polyvinyl alcohol (PVA), styrene-butadiene copolymer (SBR), acrylic resin, acrylic-modified urethane resin, styrene/acrylic resin, ethylene/acrylic resin, urethane resin, rosin-modified maleic acid resin, vinyl chloride/acetic acid resin Vinyl copolymers, polyvinyl acetal resins, polyamide resins, cellulose resins such as hydroxyethyl cellulose, hydroxypropyl cellulose, and nitrocellulose, polyolefin resins, polyamide resins, biodegradable resins, other resins such as cellulose resins, and paper. Base materials, metal materials, etc. can be used.

Note that the above resins and fillers are just examples, and other materials can be used as long as they satisfy processability and functionality.

In the above configuration, it is preferable to use a white or transparent resin.
Transparent here means that the light transmittance in the visible light region is 30% or more on average in the visible light region.

Next, the first coloring layer 102, the second coloring layer 104, the third coloring layer 106, the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 will be explained.
The first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 include polymethine cyanine dyes, polymethine dyes, squarylium dyes, porphyrin dyes, metal dithiol complex dyes, and phthalocyanine dyes. Dyes, diimonium dyes, inorganic oxide particles, azo dyes, naphthoquinone and anthraquinone quinone dyes, cerium oxide, indium tin oxide, tin antimony oxide, cesium tungsten oxide, lanthanum hexaboride, etc. can be used. It is.

The binder resins contained in the first coloring layer 102, second coloring layer 104, and third coloring layer 106 include nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose propionate, cellulose acetate, cellulose propionate, and palmitic acid. Cellulose esters such as cellulose, cellulose myristate, cellulose acetate butyrate, and cellulose acetate propionate, polyester resins, cellulose resins such as hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl cellulose, methyl cellulose, and cellulose acetate can be used. .

The binder resin contained in the first coloring layer 102, second coloring layer 104, and third coloring layer 106 includes vinyl resins such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, and polyacrylamide, and polymethyl Acrylic resins such as acrylate and polyacrylic acid, polyolefins such as polyethylene and polypropylene, polyacrylate resins, epoxy resins, and phenolic resins can also be used.

In particular, representative examples include PET resin, PETG, PVC resin, PVA resin, PC resin, PP resin, PE resin, ABS resin, polyamide resin, and vinyl acetate resin. Furthermore, as the first coloring layer 102, second coloring layer 104, and third coloring layer 106, it is possible to use copolymers based on these resins or materials to which additives such as silica, calcium carbonate, titanium oxide, and carbon are added. be.

The first coloring layer 102, the second coloring layer 104, and the third coloring layer 106 are made of highly transparent resins such as polyvinyl alcohol, polyvinyl acetate, and polyacrylic as a binder, and the temperature exceeds a certain threshold value. As the coloring material that sometimes develops color, a leuco dye, a leuco dye, a temperature-indicating material, and a color developer are used.

Examples of leuco dyes, leuco pigments or temperature-indicating materials include 3,3-bis(1-n-butyl-2-methyl-indol-3-yl)phthalide, 7-(1-butyl-2-methyl-1H-indole- 3-yl)-7-(4-diethylamino-2-methyl-phenyl)-7H-furo[3,4-b]pyridin-5-one, 1-(2,4-dichloro-phenylcarbamoyl)-3, 3-Dimethyl-2-oxo-1-phenoxy-butyl]-(4-diethylaminophenyl)-carbamic acid isobutyl ester, 3,3-bis(p-dimethylaminophenyl)phthalide, 3,3-bis(p- dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone = CVL), 3,3-bis(p-dimethylaminophenyl)-6-aminophthalide, 3,3-bis(p-dimethylaminophenyl)- 6-nitrophthalide, 3,3-bis3-dimethylamino-7-methylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7- Anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 2-(2-fluorophenylamino)-6-diethylaminofluorane, 2-(2-fluorophenylamino)-6-di- n-Butylaminofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-(N-ethyl-p-toluidino)-7-(N-methylanilino)fluorane, 3-(N-ethyl- p-Toluidino)-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6 -Methyl-7-anilinofluorane, 3-N,N-diethylamino-7-o-chloroanilinofluorane, Rhodamine B lactam, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3- Color-forming dyes such as benzylspironaphthopyran can be used.

Further, as the color developer, any acidic substance used as an electron acceptor in a thermosensitive recording material can be used.
For example, inorganic substances such as activated clay and acid clay, inorganic acids, aromatic carboxylic acids, their anhydrides or metal salts, organic color developers such as organic sulfonic acids, other organic acids, and phenolic compounds are used. Among the coloring agents, phenolic compounds are preferred.

Specific examples of the color developer include bis-3-allyl-4-hydroxyphenylsulfone, polyhydroxystyrene, zinc salt of 3,5-di-t-butylsalicylic acid, zinc salt of 3-octyl-5-methylsalicylic acid, Phenol, 4-phenylphenol, 4-hydroxyacetophenone, 2,2'-dihydroxydiphenyl, 2,2'-methylenebis(4-chlorophenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol) , 4,4'-isopropylidene diphenol (also known as bisphenol A), 4,4'-isopropylidene bis(2-chlorophenol), 4,4'-isopropylidene bis(2-methylphenol), 4,4' Ethylene bis(2-methylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), 1,1-bis(4-hydroxyphenyl)-cyclohexane, 2,2'-bis(4 -Hydroxyphenyl)-n-heptane, 4,4'-cyclohexylidenebis(2-isopropylphenol), 4,4'-sulfonyldiphenol and other phenolic compounds, salts of these phenolic compounds, salicylic acid anilide, novolak Examples include type phenolic resin, benzyl p-hydroxybenzoate, and the like.

Next, the first intermediate layer 103 and the second intermediate layer 105 will be explained.
As the first intermediate layer 103 and the second intermediate layer 105, polypropylene (PP), polyvinyl alcohol (PVA), styrene-butadiene copolymer (SBR), polystyrene, polyacrylic, or the like can be used.

The protective layer 107 may be provided as necessary, and its specific functions include mechanical protection and UV protection, as well as prevention of counterfeiting of holograms, lenticular lenses, microarray lenses, UV-excited fluorescent inks, etc. It may be made to have a function such as an item.
Further, since it is necessary to visually recognize the color recording or monochrome recording recorded under the protective layer 107 after the recording is completed, colorless and transparent is preferable.

Next, the recording process on the recording medium MD in the image recording apparatus 10 will be explained.
The image recording apparatus 10 of this embodiment scans the recording medium MD line by line and records an image pixel by pixel.

In this case, if the distance between the optical fibers FBY, FBM, and FBC, that is, the distance between the recording positions, is set to m (m is an integer) times the distance between pixels, the scanning will be as follows: This is done in units of m times the distance between pixels.
More specifically, when m=3, scanning is performed in units of distance three times the distance between pixels.

In this case, based on the image data GD, the optical fiber FBY for yellow coloring emits laser light (center wavelength = PK1), and the optical fiber FBM for magenta coloring emits laser light (center wavelength = PK2). , the cyan coloring optical fiber FBC irradiates laser light (center wavelength=PK3).

In this case, when the scanning direction is along the X direction, the recording medium MD on the stage is driven by the X direction table, and the optical fiber FBY for yellow coloring is located at the beginning in the scanning direction, When coloring is first performed in the direction, the optical fiber FBY is moved to the recording position, and when the optical fibers FBM and FBC are at the recording target position with the position of the optical fiber FBY as a reference, recording is performed. becomes.

Thereafter, scanning is performed in the same manner, moving to the nearest recording position in the scanning direction, recording is performed, and an image is formed.
More specifically, the recording position where only the laser light (center wavelength=PK1) is irradiated by the optical fiber FBY is colored yellow.

Further, the recording position where only the laser light (center wavelength=PK2) is irradiated by the optical fiber FBM is colored magenta.
Further, the recording position where only the laser light (center wavelength=PK3) is irradiated by the optical fiber FBC is colored cyan.

Furthermore, at the recording position where the laser light (center wavelength = PK1) is irradiated by the optical fiber FBY and the laser light (center wavelength = PK3) is irradiated by the optical fiber FBC, red (= yellow + cyan) is produced. .

Furthermore, at the recording position where the laser light (center wavelength = PK2) is irradiated by the optical fiber FBM and the laser light (center wavelength = PK3) is irradiated by the optical fiber FBC, blue (= magenta + cyan) is produced. .

Furthermore, at the recording position where the laser light (center wavelength = PK1) is irradiated by the optical fiber FBY and the laser light (center wavelength = PK2) is irradiated by the optical fiber FBM, green (= yellow + magenta) is produced. .

Furthermore, optical fiber FBY irradiates laser light (center wavelength = PK1), optical fiber FBM irradiates laser light (center wavelength = PK2), and optical fiber FBC irradiates laser light (center wavelength = PK3). At the irradiated recording position, black (gray) (=yellow + magenta + cyan) is developed.
As a result, multicolor recording using yellow, magenta, and cyan as the three primary colors can be performed.

As described above, according to the first embodiment, the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 each have a plurality of photothermal conversion materials each having an absorption spectrum with a different absorption peak. A first coloring layer 102, a second coloring layer 104, and a third coloring layer 106 are configured as thermosensitive coloring layers, each of which has a composite absorption spectrum of a plurality of light-to-heat conversion materials as its absorption spectrum.
Therefore, in the effective absorption spectra (synthetic absorption spectra) of the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110, the region with high absorption rate is flat as a whole.
As a result, when the first coloring layer 102, the second coloring layer 104, and the third coloring layer 106 develop color, they are less susceptible to temperature changes during operation of the laser diode LD itself or to the surrounding environment temperature.
That is, the effective absorption spectra (combined absorption spectra) of the first photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110 are flat as a whole in the region where the absorption rate is high. The first coloring layer 102, the second coloring layer 104, and the third coloring layer 106 are free from temperature changes during operation of the laser diode LD itself, the effects of ambient temperature, or in other words, the effects of fluctuations in the center wavelength of the recording light. It is possible to stably record an image with a desired density by reducing the amount of water, and as a result, a full-color image having a desired tone can be obtained.

[2] Second Embodiment The first embodiment described above is an embodiment in which full-color image recording is performed, but the present second embodiment is an embodiment in which monochrome image recording is performed.
The configuration of the image recording apparatus of the second embodiment is the same as that of the first embodiment, so the detailed description will be cited here.

Here, the recording medium of the second embodiment will be explained.
Since the recording medium of the second embodiment records monochrome images, a coloring layer and a protective layer are formed in this order on the base material.

Here, a photothermal conversion material for producing black (BK) coloring is dispersed (mixed) in the coloring layer.

In the second embodiment, the coloring layer develops a black color due to heat at a temperature equal to or higher than a predetermined temperature threshold, but as shown by the absorption spectrum SPMC in FIG. Light is absorbed in a wide wavelength range including the absorption peak of any of the photothermal conversion material 108, the second photothermal conversion material 109, and the third photothermal conversion material 110, and photothermal conversion is performed.

The reason why photothermal conversion materials are able to perform photothermal conversion over a wide wavelength range is because multiple photothermal conversion materials with different absorption peaks are mixed to achieve flatter light absorption characteristics. It is.

With this configuration, color can be generated by any of the laser diodes LD in the first embodiment without being affected by environmental temperature or temperature changes during operation of the laser diode LD itself, and a stable monochrome image can be produced. Can record.

As described above, according to the second embodiment, images of three pixels can be recorded simultaneously using three optical fibers, so images are recorded three times faster than in the first embodiment. can be done. Generally speaking, when recording monochrome images using n optical fibers, n pixels are recorded in one recording, compared to recording multicolor images using n optical fibers using n colors. Since image recording can be performed, image recording can be performed at a maximum speed of n times.

Even in this case, the optical fibers that perform recording at the same time can be placed spatially apart, so that the effect of heat generated in one recording target pixel on other recording target pixels during image recording can be minimized. This enables stable image recording.

Furthermore, recording of adjacent pixels can be separated in time, making it possible to achieve both stable recording and high-speed recording.
Furthermore, since image recording is performed on adjacent pixels after a predetermined period of time has elapsed, it is possible to achieve both stable recording and high-speed recording.

[3] Modification of Embodiment The control unit of the image recording apparatus of this embodiment has a hardware configuration using a normal computer.

The program executed by the image recording device of this embodiment is a file in an installable or executable format, and is stored in a semiconductor memory device such as a USB memory, an SSD (Solid State Drive), or a DVD (Digital Versatile Disk). Provided recorded on a computer-readable recording medium.

Further, the program executed by the image recording apparatus of this embodiment may be stored on a computer connected to a network such as the Internet, and may be provided by being downloaded via the network. Furthermore, the program executed by the image recording apparatus of this embodiment may be provided or distributed via a network such as the Internet.

Furthermore, the program to be executed by the image recording apparatus of this embodiment may be provided by being incorporated in a ROM or the like in advance.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

For example, in the above explanation, the recording head is fixed and the recording medium is driven and scanned, but it is also possible to configure the recording head to scan and the recording medium to be fixed. be.

Further, in the above description, a case has been described in which three colors, yellow, magenta, and cyan are used for full-color recording, but it is also possible to use four or more colors.
It is also possible to perform recording in two colors (for example, black and red).

In these cases, when the number of colors to be used (the number of coloring layers of different colors) is n (n is an integer of 2 or more), at least the distance between the recording positions of the optical fiber is the distance between pixels (pixel center The distance may be n times the distance (distance between positions).
Note that in this case, if the scanning speed is high, there is a risk that the pixel to be recorded will be affected by heat in adjacent pixels, so it is preferable to set a distance that is an integral multiple of n.

In the above description, the case where an optical fiber is used as the light guide member has been described, but the light guide member is not limited to this, and it is also possible to configure it with a sheet-like or plate-like optical waveguide.
Furthermore, although one condensing lens is used as the light guide member, it is also possible to provide a microlens corresponding to each light guide member.

10 Image recording device 11 Calculation unit 12 Position control unit 13 Light source unit 14 Output control unit 15 Fiber unit 16 Recording head unit 17 Holding drive unit 31 Fiber housing 32 Condenser lens 33 Casing 41 Stage 42 X-direction table 43 X-direction drive motor 44 Y-direction table 45 Y-direction drive motor 101 Base material 102 First coloring layer (thermosensitive coloring layer)
103 First intermediate layer 104 Second coloring layer (thermosensitive coloring layer)
105 Second intermediate layer 106 Third coloring layer (thermosensitive coloring layer)
107 Protective layer 108 First photothermal conversion material 109 Second photothermal conversion material 110 Third photothermal conversion material A to V Pixel position FBC Optical fiber (cyan)
FBM optical fiber (magenta)
FBY optical fiber (yellow)
GD Image data LD Laser diode MD Recording medium

Claims (6)

A thermosensitive coloring layer including a plurality of photothermal conversion materials each having an absorption spectrum with a different absorption peak, and whose absorption spectrum is a composite absorption spectrum of the plurality of photothermal conversion materials.
recoding media. A plurality of thermosensitive coloring layers each having different center absorption wavelengths of the synthetic absorption spectra and different temperature thresholds for coloring and capable of independently developing color;
The recording medium according to claim 1. The plurality of heat-sensitive coloring layers are laminated,
The thermosensitive coloring layer having a shorter central absorption wavelength is laminated closer to the recording light incident side.
The recording medium according to claim 2. The total thickness of the layers including the plurality of thermosensitive coloring layers is less than or equal to the depth of focus of the recording light,
The recording medium according to claim 2 or claim 3. The thermosensitive coloring layer is provided with n layers (n is an integer of 3 or more) that differ in color from each other when colored, and multicolor recording is possible.
The recording medium according to any one of claims 2 to 4. The thermosensitive coloring layer is capable of absorbing a plurality of recording lights having different center frequencies, and has the composite absorption spectrum capable of coloring with respect to any of the recording lights among the plurality of recording lights.
The recording medium according to claim 1.

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