JPH0451517B2 - - Google Patents

Description

[Detailed description of the invention]

<<Industrial Application Field>> The present invention relates to a color photograph that can be stored forever, and particularly to a permanent color photograph that does not contain any organic matter and has excellent color reproduction. <<Prior Art>> In recent years, photographic technology has made significant progress as the demand for photographs, especially color photographs, has expanded. However, because photographic images are formed in organic materials, or because the reproduced color images are based on organic dyes, the heat resistance, moisture resistance,
Although improvements in light resistance have been made and techniques for providing a protective layer such as acrylic resin on the image surface have been developed, there are limits to the preservation of photographic images. As a reproduction method that solves these drawbacks of photographs, there has been a known method of producing permanent reproductions by intaglio printing or screen printing using inorganic pigments on a ceramic plate and firing it. It is being However, it is impossible to obtain the same resolution and gradation as a photograph using this method, especially for relatively small images.
There are limits to the faithful reproducibility of images, and because printing equipment and technology are required, its use has naturally been limited. Furthermore, in order to produce color reproductions, the firing temperature of pigments had to be set independently according to the type of pigment, so the pigments had to be fired in order of firing temperature to reproduce color. The drawbacks were that it was complicated and had limited color reproduction. On the other hand, there is a method in which an image is formed by subjecting a photocurable element to imagewise exposure to solidify the non-image area and developing the uncured and tacky image area with toner; It is known to form a color image by repeating the above steps after further providing a photocurable element (for example, US Pat. No. 3,649,268). If this method is used, it is possible to perform development with inorganic pigments and the discoloration of the image can be avoided, but since the substance supporting the pigment is organic,
It is impossible to store the resulting image permanently without alteration. It is also known to produce a monochromatic permanent photograph by imagewise exposing a photosensitive resin on ceramic, developing it with a slurry containing an inorganic pigment, and then firing. However, when forming a multilayer image using this method and firing it, the solvent molecules forming the slurry remain in the photosensitive resin and evaporate during firing, destroying the image. The disadvantage was that it was impossible to form a color image using this method. Further, a ceramic transfer body for coloring and baking ceramics manufactured by an offset printing method is also known. Although this method provides higher resolution than screen printing, it is still extremely complicated. In any case where firing decoration is applied to ceramics using the above-mentioned printing techniques, it is not only not possible to use only pigments for decoration, but also it is not possible to use printing ink made by mixing only the pigments in a vehicle. The printing material is powder paint, which is a mixture of coloring matter and flux, or paint ink. However, it has generally been thought that when flux is mixed in this way, the density of the printing pigment is diluted by the flux, and a sufficient printing color density cannot be expected. In addition, selenium-based red paint, which is the most vivid red pigment for ceramics, became unusable due to its weak covering power, and iron red and tin oxide pink, which had dull red or pink color and brightness, had to be substituted. As a result, faithful printing color reproduction of color originals is completely impossible. In addition, the melting temperatures of the ceramic dyes used conventionally vary, and in order to bring out the vivid color of each dye, it is necessary to use the dyes in descending order of melting temperature, which is complicated. On the other hand, a transfer body for ceramics is made by appropriately overlapping a printing layer that reproduces a color original using the offset method and a printing layer of fritted glaze, which melts at the baking temperature and adheres and fixes the painting pigment in the printing layer to the surface of the ceramic product. A manufacturing method is provided (Japanese Patent Application Laid-Open No. 14913/1983). This method is complicated as it requires a large number of printing plates to be produced in order to produce a single transfer material, and although it can improve gradation and color reproduction to a certain extent,
It is difficult to achieve gradation comparable to that of photographs. Furthermore, especially when printing on ceramics having a curved surface, uneven tension is applied to the transfer body, which is originally made in a flat shape, resulting in a drawback that color shift is likely to occur during printing. Regarding color reproduction, for example, when the selenium red used in the above-mentioned document is used, it becomes magenta with strong yellow, and even with this technique, it is impossible to reproduce skin color. Regarding color reproduction, the same applies to cases where a painting method that does not use printing technology is used. This is because in this industry, the main focus was on bringing out the vividness of each color, and the color development of ceramic pigments often changes greatly depending on trace amounts of metals mixed in.
This is because it is extremely difficult to reproduce a desired color by mixing various dyes. Therefore, in this technical field, there is no literature on reproduction of skin color by color mixture, and of course, there is no known combination of inorganic pigments that can reproduce skin color in one firing. <<Problems to be Solved by the Invention>> As a result of intensive research in order to solve these conventional drawbacks, the present inventors have repeatedly carried out dry development in which inorganic pigment particles are attached to a photosensitive element that has been exposed to light for image formation. If a multilayer image is formed thereon and then fired under certain conditions, the photosensitive element is easily erased without destroying the image, and a permanent color photographic image of good quality can be obtained; The present invention was achieved by discovering a combination of pigments with substantially the same melting point that can achieve good color reproduction. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a permanent color photograph that has good resolution, gradation, color reproduction, etc., can faithfully reproduce image areas, and does not undergo discoloration or fading. <<Means for Solving the Problem>> That is, the present invention is a color photograph in which a permanent color image made of an inorganic pigment is provided on a substrate made of an inorganic material and/or a metal such as silver or copper. A mixture of sea blue and freshwater colors for cyan, yellow for yellow, Seyenko or a mixture of Maron and Seyonko for magenta, and Sekoku for black, selected from pottery overpaints as pigments. This is a permanent color photograph characterized by the fact that it is used as a set. As the substrate used in the present invention, any substrate can be used as long as it can withstand heating of 400° C. or higher. Such materials generally include plates made of so-called ceramic materials, other ceramic materials, inorganic materials such as high-melting point glass, or plates made of iron, aluminum, copper, and other metals or alloys. . A substrate made of an inorganic material and/or a substrate made of a metal such as copper or silver is preferable because the inorganic pigment that forms the image can be directly fused and integrated with the substrate, but from the viewpoint of cost, it is especially preferable to use an inorganic material. The substrate is preferred. When using metal materials such as iron or aluminum, in order to ensure good adhesion between the pigment and the substrate, it is necessary to provide a subbing layer on the substrate or to adjust the thermal expansion coefficient of the image area and the substrate. It is desirable to add other additives containing silica as the main raw material to the pigment in order to make them substantially the same. In the present invention, the photosensitive element provided on the substrate can be applied by brush or roller coating, or by dip coating, or by spraying a liquid containing the photosensitive element onto the substrate, or by pouring the liquid onto the substrate rotated using a wheller. Generally, any method for forming a photosensitive layer such as a printing plate can be used. The photosensitive element used in the present invention includes a polymer compound having a group capable of polymerization reaction or crosslinking reaction by light irradiation, as well as a non-reactive polymer itself, but a mixture with a photopolymerizable monomer. compositions, or so-called photosensitive compositions that rapidly change chemical and physical properties when irradiated with light, such as polymer compositions containing a crosslinking agent that crosslinks between polymers. It is possible to use anything. These photosensitive compositions may contain a known sensitizer, if necessary, in order to increase sensitivity, and if necessary, a sensitizer may be added between the substrate and the photosensitive layer for development. An adhesive layer can also be provided for durability. In the present invention, imagewise exposure is carried out through a positive film when a photocurable composition is used as the photosensitive element, or through a negative film when a photodegradable composition is used. In particular, in order to obtain a color image, it is necessary to use a negative film or a positive film that has been subjected to halftone color separation. For exposure, all light sources normally used for exposing photosensitive resins can be used, but
Among them, a high-pressure mercury lamp or an ultra-high-pressure mercury lamp is preferable.
In particular, a so-called metal halide lamp is preferred. It is preferable to provide a certain amount of overall exposure in addition to the normal imagewise exposure using these lamps, since this improves the gradation reproducibility in shadow areas. In the present invention, development is carried out by preparing a slurry containing pigments and pouring or spraying the slurry onto the exposed photosensitive element, or by applying powder onto an image swollen with a solvent or solvent vapor. This can be done by wiping with a cloth, fur, etc. carrying the toner. When developing with a slurry containing a pigment, the slurry contains a solvent that swells the image area of the photosensitive element, and a dispersant (for example, methanol,
It is necessary to mix it with an alcohol dispersant (such as isopropyl alcohol, n-butyl alcohol, etc.). In contrast, development with powdered toner is performed in an atmosphere of solvent vapor that causes the image area to swell, or in an atmosphere that is substantially free of solvent vapor.
Since this is a dry development method in which the toner is developed using a dry cloth or fur or passed through a developing chamber in which the toner is suspended in an agitated atmosphere, unevenness can be eliminated by applying an appropriate pressure or adjusting the stirring intensity of the atmosphere. It can be developed uniformly without any
Moreover, it is preferable because good resolution can be obtained. As the pigment used in the present invention, if color reproduction comparable to photography is not required, any pigment that does not disappear even when heated at 500°C or higher can be used; from this point of view, All inorganic pigments can be used. In this case, coloring techniques used in crafts are referred to (for example, "Illustrated Ceramics for Crafts" by Yoichi Soki, published by Gihodo Co., Ltd. (1975)).However, faithful color reproduction similar to that in photographs is required. In particular, in order to form an image with a certain combination of pigments in only one firing, it is necessary that the melting points be approximately the same. Furthermore, as a result, it is necessary to select a combination of pigments that is good for flesh color reproduction, which determines photographic value.Pigments that develop a good magenta color after heating at 500°C or higher are particularly preferred as overpaints for pottery. Therefore, by selecting cyan, yellow, and black, which are necessary for color image reproduction, from the top paint, it is possible to reproduce good skin tones in one firing.As is well known, the top paint is made of lead called Flux. It consists of glass Frit and a pigment whose color forming substance is an inorganic metal oxide.As mentioned above, the overpaint is the pigment used in the present invention, so in that sense, the pigment in this specification is the same as the commonly used pigment. In the present invention, Frit is preferable without containing feldspar, and in particular, K ₂ O, PbO-SiO ₂ system and Na ₂ O,
PbO-SiO ₂ based Frit is preferred. In addition, ceramic paints that are usually classified as cyan, magenta, and yellow cannot generally reproduce pure cyan, magenta, and yellow, respectively, even if they are printed as individual colors. A special combination of paints is required to reproduce the desired color. Pigments for good skin color reproduction include, for cyan, a mixture of sea blue and freshwater colors that use cobalt oxide as a coloring substance, and for yellow, yellow that uses antimony oxide and/or cadmium as a coloring substance. For magenta, it is preferable to use cassius purple gold and a mixture of shoenko and marron, in which maron is added as a coloring substance, if necessary, and for black, tsukuro is preferable. The mixing ratio of sea blue and freshwater color (sea blue/freshwater color) is 3/2 to 1/6, preferably 1/1 to 1/5,
The ratio of Maron and Seienko (Maron/Seienko) is 0 to 1/
2, preferably 1/15 to 1/3. If only freshwater color is used as cyan, the cyan density will be insufficient, and if only sea blue is used, the cyan density will be too strong. If only true round stone is used as magenta, the magenta density tends to be insufficient, and if only maron is used, the magenta density is too high, which is not preferable. Specific examples of pigments used in the present invention include the following. However, the numerical values in the table represent weight %.

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[Table] However, the maroon base in the table is tin/gold =
Represents a 1/4 purple base.

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[Table] The particle size of the toner used in the present invention is about 0.2 to 30μ, and inorganic pigments or mixtures thereof can be used as they are. The particle size of the toner used determines the resolution of the final image obtained, and permanent color images of up to 175 lines per inch can be obtained with the present invention. In the present invention, the surface of the pigment particles may be covered with a resin or treated with a surfactant so that the toner easily adheres to the swollen image area. Adjustment of toner adhesion is important not only for improving the gradation of images but also for improving the workability for producing permanent photographs. Generally, to reproduce a color image, it is necessary to mix at least cyan, yellow, and magenta, and to improve color reproduction, it is also necessary to mix black. It requires a lot of color mixing. In the present invention, pigments are deposited one color at a time, so it is necessary to repeat the process of exposing and developing a photosensitive element provided for image reproduction of each color through a color-separated lithium film. . In the present invention, when emphasis is placed on skin color reproduction as the color reproduction standard, the magenta image must be formed before the black image, but among others:
It is particularly preferable to form color images in the order of cyan, yellow, magenta, and black. The color image thus obtained becomes a permanent color photograph by illuminating the entire substrate at a temperature of 400°C or higher. When glass having a softening point of about 400°C is used as the substrate, the firing temperature is about 400°C. In this case, the pigment does not melt completely, but it sticks to the substrate to soften the substrate surface. In this case, in order to match the coefficient of thermal expansion of the substrate, it is possible to strengthen the bond between the substrate and the pigment by adding an appropriate additive to the pigment, such as adding fine powder of substrate glass to the pigment. I can do it.
When using a material with an extremely high melting point, such as a ceramic plate, as a substrate, it is necessary to bake at a temperature of 500°C or higher, preferably 550°C or higher, at which the pigment can be melted, to firmly fuse the pigment to the substrate. be. When using pigments with a high melting point, such as so-called base paints used in crafts, the firing temperature is approximately 1300℃.
It is possible to increase it to a certain degree. however,
When using a so-called top paint to reproduce a good magenta color by firing, firing is performed at 500 to 850°C, preferably 600 to 750°C. In this firing process, organic substances other than pigments completely disappear, but if the heating rate is too high, image destruction such as pigment falling off occurs during the process of disappearance of organic substances, which is undesirable. Therefore, the firing process must be carried out with particular care up to a temperature at which the photosensitive element disappears. Most photosensitive elements can disappear at about 200°C, so from room temperature to about 200°C
It is preferable that the rate of temperature increase to 0.degree. C. is about 4.degree. C./min or less, particularly preferably about 3.degree. C./min or less. The most reliable method for manufacturing permanent color photographs is to manufacture a first permanent photograph, then place a new photosensitive element on its surface and repeat the process of manufacturing the first permanent photograph. In this way, at least cyan, magenta and yellow images, preferably also black images, are formed, and by mixing these colors a permanent color photograph can be produced. This is an additional 2 on top of the single color permanent photo.
It is complicated because it involves layering colors one after another on top of the permanent photo, such as overlapping permanent photos of different colors. In order to avoid such complexity, if inorganic pigments having substantially the same melting point are used, the firing step can be performed only once after the final development process. The first such method is to expose the entire surface of the photosensitive element after processing to sufficiently harden the non-image areas, and then coat the photosensitive element for a new color image. A second method includes a method of using a thermophotocurable composition as a photosensitive element. That is, in this case, the photosensitive element is cured in such a way that it is possible to apply a new photosensitive element onto the photosensitive element after processing without affecting the image obtained thereon. All you have to do is apply sufficient heat. Another way to avoid the complexity of the firing process is to
An intermediate layer may be provided between the photosensitive elements to prevent the already formed image from being affected by the application of the photosensitive elements. <<Effects of the Invention>> The photographs obtained by the present invention have a permanent shelf life since neither the substrate nor the image contains any organic substances. In other words, since the image is made of inorganic pigments, it will not change color or fade, and since the image is reproduced using lithium film, it is a permanent photograph with the same resolution and gradation as a photograph, and is suitable for viewing. It is also extremely useful as a recording material for long-term storage. The color photographs obtained by the present invention are fully satisfactory in terms of color reproduction, and have good resolution and gradation, so they can be fully appreciated, especially as relatively small permanent color photographs. It has created new value. <<Example>> In order to explain the present invention in more detail, the present invention will be described below according to Examples, but the present invention is not limited thereto. Example 1 A photosensitive element containing polyvinyl alcohol cinnamic acid ester as a main raw material was coated on a ceramic plate measuring 11 cm x 11 cm to a dry thickness of about 5 μm. Next, the film was passed through the halftone-resolved positive film using a metal halide ultra-high pressure mercury lamp (1 kilowatt).
After exposure for 75 seconds from a distance of 50 cm, the transmittance is further increased to 10
% filter for 2 seconds.
After exposure, the ceramic plate was exposed to an atmosphere of saturated n-butyl acetate vapor (25°C) for 5 minutes to swell the image area, and then applied to the sea blue and freshwater colors of top paints used in crafts (both from Isekyu Co., Ltd.). A mixture of (sea blue/freshwater color = approx. 0.80) made by M. Co., Ltd. was applied as a pigment to a soft cloth and developed, and the excess pigment was removed with a chamois. As a result, a cyan image with good resolution and gradation was obtained on the ceramic plate. Next, the developed ceramic plate is placed in a room-temperature oven with an oxidizing atmosphere, and heated to 200°C at a heating rate of approximately 2°C/min.
After about 70 minutes, the mixture was heated and baked at 650°C. By this firing, the layer of the photosensitive element completely disappeared, the pigment was firmly fused to the substrate, and a permanent photograph of a beautiful cyan image was obtained which reproduced the resolution and tonality of the photograph. This entire process was repeated for a yellow image using light yellow from Kajita Eguten LLC as a pigment to form a permanent photograph consisting of cyan and yellow, and similarly for Maron and Shoenko from Isekyu Co., Ltd. A permanent color photograph was obtained by superimposing a magenta image using a mixture (Maron/Seienko = approximately 0.08) as a pigment and a black image using Sengoku, also manufactured by Isekyu Co., as a pigment.
The obtained permanent photographic image had good resolution and gradation, and color reproduction was almost satisfactory. Example 2 Using pigments made by Kajita Eguten LLC, cyan was a mixture of sea blue/freshwater color = approximately 0.79, yellow was pale yellow, magenta was a mixture of flower marron/seienko = approximately 0.3, and black was a mixture of approximately 0.3. A permanent color photograph was obtained in the same manner as in Example 1, except that black color was used. The color reproduction of the obtained image was extremely satisfactory, and the resolution and gradation were as good as in Example 1. Example 3 A permanent color photograph was produced in the same manner as in Example 2, except that instead of the final firing, the photosensitive element was cured by burning at 110° C. for 15 minutes. I got it. The obtained image was very good as in Example 2,
It was enough to be appreciated as a photograph. Example 4 Instead of performing the burning of Example 3, a thin film of about 1 μm of polyvinylpyrrolidone was applied over the layer of the photosensitive element, and the final firing step was carried out for about 2 hours and 50 minutes at a substantially constant temperature increase rate. The temperature is raised from room temperature to approximately 200℃,
Further, a permanent color photograph was obtained in the same manner as in Example 3, except that the temperature was heated to about 650° C. after about 1 hour and 10 minutes. The obtained color image is the same as that of Example 3.
As in the case of , the results were extremely good. Example 5 Instead of the photosensitive element whose main raw material was cinnamic acid ester of polyvinyl alcohol used in Example 3, a photosensitive element whose main raw material was polyvinyl paraazide benzoate (manufactured by Fuji Pharmaceutical Co., Ltd.) was used.
A permanent color photograph was obtained in the same manner as in Example 3, except that FPER) was used. In this case as well, the obtained images were sufficiently good and satisfactory.

Claims (1)

[Scope of Claims] 1. A color photograph in which a permanent color image made of an inorganic pigment is provided on a substrate made of an inorganic material and/or a metal such as silver or copper, wherein the inorganic pigment is made from ceramic top paint. A mixture of sea blue and freshwater colors for the selected cyan, yellow for yellow, Seiko or a mixture of Maron and Seiko for magenta, and black for black are used as a set. A permanent color photo featuring 2. A permanent color photograph according to claim 1, wherein a magenta image is formed before a black image. 3. A permanent color photograph according to claim 2, wherein a four-color image separated into three colors is formed in the order of cyan, yellow, magenta, and black.