JP7084145B2 - Inkjet water-based ink compositions and solid formulations - Google Patents

Description

The present invention relates to a water-based ink composition for inkjet and a solid preparation, and more specifically, it is possible to easily adjust the color tone and hue and print an image on the surface of a solid preparation such as a pharmaceutical product or a food without impairing the ejection property. The present invention relates to a water-based ink composition for inkjet and a solid preparation.

Ink for inkjet used for printing on solid formulations such as pharmaceuticals and foods (for example, tablets and capsules) includes dye inks using dyes and pigment inks in which pigments are dispersed (for example, Patent Document 1). It is roughly divided. In general, dye inks have the advantage of having various colors and excellent vivid color development, but have the disadvantage of being easily faded and inferior in light resistance. On the other hand, the pigment ink has an advantage that it is hard to fade and has an excellent light resistance as compared with a dye ink, but has a disadvantage that it is inferior in color development as compared with a dye ink. Therefore, from the viewpoint of printing an image having excellent light resistance on a solid preparation, it is preferable to use a pigment ink.

However, in order to enable printing on solid formulations using pigment ink, for example, in Japan, the pigment ink conforms to the standards of the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia, or the Official Food Additives. It is necessary to do. In Japan, some pigments that meet the standards for pharmaceutical additives, etc. stipulated by the Pharmaceutical Affairs Law are not permitted to be used in pharmaceutical products, etc. in some countries. Therefore, in each country, the pigment inks that can be printed on the solid product are limited, and there is a problem that it is difficult to freely change the color tone and hue of the printed image according to the color of the solid product. .. Further, since the pigment ink is inferior in color development to the dye ink, it is difficult to print an image having excellent visibility. It is conceivable to increase the content of the pigment in order to improve the color development property, but in that case, there is a problem that the ejection property of the inkjet head is lowered and it becomes difficult to print a good image.

JP-A-2015-140414

The present invention has been made in view of the above problems, and an object thereof is to be able to easily adjust the color tone and hue of a solid preparation such as a pharmaceutical product or a food product without impairing the ejection property and print an image. The present invention is to provide an aqueous ink composition for inkjet and a solid preparation.

The water-based ink composition for inkjet according to the present invention is a water-based ink composition for inkjet used for printing on a solid preparation in order to solve the above-mentioned problems, and comprises an edible pigment and an edible dye. The pigment is contained in the aqueous ink composition for inkjet in a dispersed state, and the dye is dissolved and contained in the aqueous ink composition for inkjet within a range in which the dye does not precipitate. The contents of the pigment and the dye are each 10% by mass or less with respect to the total mass of the water-based ink composition for inkjet.

In general, inks containing pigments (hereinafter referred to as "pigment inks") have excellent light resistance, and therefore, compared with inks containing dyes (hereinafter referred to as "dye inks"), fading of printed images due to aging. And the progress of discoloration can be suppressed. However, since pigments are inferior in color development to dyes, the visibility of images may deteriorate when an image is printed on tablets or capsules such as pharmaceuticals with pigment ink.

On the other hand, since the water-based ink composition for inkjet having the above structure (hereinafter, may be referred to as "water-based ink composition") contains at least one pigment and one dye, the color development property is maintained while maintaining good light resistance. Enables printing of excellent images. Further, in the above configuration, the pigment exists in a dispersed state, and the dye is dissolved and exists in a range that does not precipitate in the aqueous ink composition. Further, the content of each of the pigment and the dye is set to 10% by mass or less with respect to the total mass of the aqueous ink composition. Therefore, in the water-based ink composition having the above structure, the ejection property from the inkjet nozzle is also well maintained.

In the above configuration, it is preferable that the dye is contained as a color tone adjuster and / or a hue adjuster.

For example, in a water-based ink composition using only a pigment as a colorant, when the pigment is excessively added in order to improve the color development property of the water-based ink composition, the ejection property from the inkjet nozzle is lowered and the water-based ink is used. The flying property of the composition may decrease. However, by using the dye as the color tone adjusting agent as in the above configuration, for example, the color tone of the water-based ink composition can be adjusted only by adding a small amount of the dye. As a result, it is possible to adjust the color tone while suppressing the deterioration of the ejection property of the water-based ink composition and improve the color development property of the printed image.

Further, by using the dye as a hue adjuster as in the above configuration, it is possible to adjust the hue of the aqueous ink composition. That is, since the water-based ink composition of the present invention is intended for printing solid preparations such as pharmaceuticals, the components contained in the water-based ink composition include pigments, pharmaceutical additives specified by the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia, or It is necessary to meet the standards of the official food additive standard. Therefore, the pigments applicable to printing solid formulations are limited, and it may not be easy to adjust the hue of the aqueous ink composition. In this case, for example, in order to adjust the hue of the aqueous ink composition, it is conceivable to mix a plurality of pigments having different hues, but it is difficult to improve the color development property. However, by containing the dye as described above, the hue of the water-based ink composition can be easily adjusted, and the water-based ink can be matched with the surface color of the solid pharmaceutical product to be image-formed. The hue of the composition can be easily adjusted.

Further, as in the above configuration, the dye can be used as both a color tone adjuster and a hue adjuster. In this case, the color tone and hue of the water-based ink composition can be adjusted at the same time. Thereby, for example, by changing the hue of the water-based ink composition to a hue different from that of the pigment, the visibility of the printed image is improved, and by adjusting the color tone, the color development of the water-based ink composition is improved. be able to.

Further, in the above configuration, the pigment is at least one selected from the group consisting of red sesquioxide, yellow sesquioxide, iron tetraoxide, carbon black, and a lake pigment, and further, the lake pigment is , Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1 and Blue No. 2 at least one selected from the group. It is preferably a laked dye.

Further, in the above configuration, the dyes are Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1, and Blue No. 2. , At least one selected from the group consisting of chlorophyllin dyes and natural dyes.

In the above configuration, the content of the pigment is preferably 0.1% by mass or more with respect to the total mass of the water-based ink composition for inkjet. By setting the content of the pigment to 0.1% by mass or more, it is possible to change the color tone when combined with the dye.

Further, in the above configuration, the content of the dye is preferably 0.01% by mass or more with respect to the total mass of the water-based ink composition for inkjet. By setting the dye content to 0.01% by mass or more, at least the color tone and / or hue of the aqueous ink composition can be adjusted.

In the above configuration, it further contains at least one fading inhibitor selected from the group consisting of monosaccharides, disaccharides, dextrins and sugar alcohols, and the content of the fading inhibitor is the water-based ink composition for inkjet. It may be 50% by mass or less with respect to the total mass of the object.

For example, dyes such as Red No. 2 have the property of penetrating into solid formulations over time due to humidity. On the other hand, monosaccharides, disaccharides, dextrins and sugar alcohols exert a function of suppressing the penetration of such dyes into solid formulations due to humidity in printed images. Therefore, it is possible to suppress the decrease in saturation of the printed image due to the penetration of the dye into the solid pharmaceutical product and reduce the occurrence of fading. Further, in an image printed by using other dyes such as natural dyes in addition to these dyes, it is also possible to prevent these dyes from separating from other dyes and permeating into the solid preparation. can. As a result, discoloration of the printed image can be reduced.

In addition, azo dyes such as Red No. 2 and indigoid dyes such as Blue No. 2 have the property of being decomposed (photodecomposed) by light irradiation, which causes the printed image to fade. There is. However, the fading inhibitor also exerts a function of suppressing photodecomposition of such dyes. Therefore, in the water-based ink composition having the above structure, it is possible to reduce the deterioration of the printed image due to the generation of light fading.

In the above configuration, by setting the content of the fading inhibitor to 50% by mass or less with respect to the total mass of the aqueous ink composition, the fading inhibitor can be sufficiently dissolved in the aqueous ink composition. It is possible to prevent the ink from precipitating.

Further, the solid preparation according to the present invention is a solid preparation having a dry film of an inkjet water-based ink on the surface in order to solve the above-mentioned problems, and the inkjet water-based ink is the inkjet water-based ink composition. Is included.

According to the above configuration, since the dry film of the inkjet ink contains at least one pigment and one dye, the printed image formed by the dry film has excellent color development while maintaining good light resistance. ing. Therefore, when the solid preparation having the above-mentioned constitution is used, the fading of the printed image formed by the dry film can be reduced, and the visibility of the printed image can be suppressed from being lowered with the change with time. In addition, since it is also excellent in color development, for example, when product information is printed, it is possible to provide a solid preparation capable of preventing dispensing mistakes, accidental ingestion, and the like.

According to the water-based ink composition for inkjet of the present invention, since the pigment and the dye are contained at least one by one, both light resistance and color development property are obtained in the image printed on the surface of the solid preparation using the water-based ink composition for inkjet. Can be improved. Further, by appropriately changing the types and blending ratios of the pigments and dyes, it is possible to print an image on a solid preparation while easily adjusting the color tone and hue without impairing the ejection property.

(Aqueous ink composition for inkjet)
An inkjet water-based ink composition (hereinafter referred to as “water-based ink composition”) according to this embodiment will be described below.
The water-based ink composition of the present embodiment is a composition containing at least one pigment and a dye as a colorant and using water as a main solvent. Further, the water-based ink composition of the present embodiment may be made edible by using a material conforming to the standards of the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia or the Food Additives Official Standard. It can be used, and can be suitably used for recording images and the like by an ink jet method.

Here, the term "edible" as used herein means a substance approved for oral administration as a drug or a pharmaceutical additive, and / or a substance approved as a food or a food additive. Further, in the present specification, the "inkjet method" means a method in which an aqueous ink composition is ejected as droplets from a fine inkjet head, and the droplets are fixed on a solid preparation to form an image. The details of the solid preparation will be described later.

The pigment is not particularly limited as long as it is edible, but is preferably selected from the group consisting of red iron sesquioxide, yellow iron sesquioxide, iron tetraoxide (black iron oxide), carbon black, and lake pigments. At least one is mentioned.

The lake pigment means a pigment obtained by laking a soluble dye in a main solvent, and more specifically, by adding a precipitating agent such as a metal salt, the dye is adsorbed on the precipitating agent and an insoluble salt (insoluble). It is a precipitate precipitated as fine particles). The dyes that are soluble in the main solvent are not particularly limited, but are preferably Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, and Green No. 3. , Blue No. 1 and Blue No. 2 are at least one selected from the group.

More specific examples of rake pigments include Red No. 2 Aluminum Lake, Red No. 3 Aluminum Lake, Red No. 4 Aluminum Lake, Red No. 40 Aluminum Lake, Red No. 102 Aluminum Lake, Yellow No. 4 Aluminum Lake, and Yellow No. 4. Barium Lake, Yellow No. 4 Zyrium Lake, Yellow No. 5 Aluminum Lake, Yellow No. 5 Barium Lake, Yellow No. 5 Zirconium Lake, Green No. 3 Aluminum Lake, Blue No. 1 Aluminum Lake, Blue No. 1 Barium Lake, Blue No. 1 Zirconium Lake , Blue No. 2 aluminum lake and the like.

The exemplified pigments are contained in the aqueous ink composition alone or in combination of two or more. The hue of the aqueous ink composition can be adjusted by mixing and containing two or more kinds of pigments. The details of "hue" will be described later.

The pigment is present in a dispersed state in the aqueous ink composition. The particle size (D50) of 50% in the integrated particle size distribution in the volume-based integrated particle size distribution of the pigment in the dispersed state is preferably in the range of 50 nm to 200 nm, and more preferably in the range of 100 nm to 150 nm. Further, the particle size (D99) of 99% in the integrated particle size distribution in the volume-based integrated particle size distribution of the pigment is preferably in the range of 100 nm to 500 nm. By setting D50 to 50 nm or more, deterioration of dispersion stability, light resistance and ejection stability can be prevented, and a decrease in print density can also be prevented. On the other hand, by setting D50 to 200 nm or less, separation and precipitation of the pigment can be prevented and dispersion stability can be maintained. When a plurality of types of pigments are contained in the water-based ink composition, D50 and D99 of the respective pigments may be included in the numerical range. The average dispersed particle diameter D50 or D99 of the pigment is a value measured by a dynamic light scattering method using Microtrac UPA-EX150 (trade name, manufactured by Nikkiso Co., Ltd.).

The content of the pigment is preferably 0.1% by mass or more, more preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5, based on the total mass of the water-based ink composition for inkjet. It is particularly preferable that it is by mass% or more and 8% by mass or less. By setting the content of the pigment to 0.1% by mass or more, it is possible to suppress the deterioration of the light resistance of the printed image. In addition, it is possible to change the color tone and / or the hue by combining with a dye. By setting the pigment content to 10% by mass or less, it is possible to suppress a decrease in ejection (stability) of the water-based ink composition in the inkjet head. When a plurality of pigments are contained in the water-based ink composition, the total content of all the pigments may be included in the numerical range.

The dye is not particularly limited as long as it is edible, but is preferably Red No. 2, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1, At least one selected from the group consisting of chlorophyllin dyes and natural dyes can be mentioned.

The chlorophyllin pigment is not particularly limited, and examples thereof include sodium iron chlorophyllin, sodium copper chlorophyllin, and sodium chlorophyllin. The natural pigment is not particularly limited, and examples thereof include cochineal pigment, cacao pigment, and caramel pigment.

The dye is present in a dissolved state in the aqueous ink composition. Further, the dye is present in a range in which the solid does not precipitate in the aqueous ink composition. The content of the dye depends on the type, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more and 10% by mass or less, based on the total mass of the aqueous ink composition. .. When the content of the dye is 0.01% by mass or more, at least the color tone and / or the hue of the aqueous ink composition can be adjusted. When a plurality of dyes are contained in the water-based ink composition, the total content of all the dyes may be included in the numerical range.

The dye can be contained as a color tone adjuster and / or a hue adjuster. For example, in an aqueous ink composition using only a pigment as a colorant, it is conceivable to change the design of the chemical structure, such as changing the side chain of the pigment, as a method for adjusting the color tone and / or the hue. However, in order to enable printing on solid formulations such as pharmaceuticals and foods, it is necessary to comply with the standards for pharmaceutical additives, etc. stipulated by the Pharmaceutical Affairs Law, and the chemical structure of the pigment in a form that conforms to the standards. It is not easy to change the design of. On the other hand, in the present invention, the chemical structure of the pigment can be obtained by simply adding an arbitrary dye as a color tone adjuster and / or a hue adjuster from among the dyes that already meet the standards for pharmaceutical additives and the like specified by the Pharmaceutical Affairs Law. The color tone and / or hue of the water-based ink composition can be easily adjusted without making design changes. In addition, even if pigments meet the standards for pharmaceutical additives, etc. stipulated by the Pharmaceutical Affairs Law in Japan, there are some pigments that are not permitted to be used in pharmaceutical products, etc. in some countries. And it becomes difficult to print an image of hue. However, in the present invention, it is possible to adjust to a desired color tone and hue simply by adding a dye as a color tone adjuster and / or a hue adjuster to a pigment approved for use in the country concerned. .. Therefore, in the present invention, it is possible to easily prepare an aqueous ink composition having a color tone and a hue that maximizes the visibility of a printed image depending on the color of the solid preparation, and the degree of freedom is high.

Further, for example, when an excessive amount of a pigment is added to an aqueous ink composition using only a pigment as a colorant in order to improve the color development property of the aqueous ink, or in order to adjust the hue of the aqueous ink composition. When a plurality of pigments having different hues are mixed, the viscosity of the aqueous ink composition may become too large and the ejection property from the inkjet nozzle may decrease. However, when a dye is used as a color tone adjusting agent, for example, the color tone of the water-based ink composition can be adjusted by adding only a small amount of the dye. As a result, it is possible to improve the color development while suppressing the deterioration of the flight property of the water-based ink composition.

Depending on the combination with the pigment, the dye can function as a color tone adjuster and a hue adjuster at the same time. In this case, the color tone and hue of the water-based ink composition can be adjusted at the same time.

In addition, in this specification, "color tone" means a color system represented by the combination of lightness and saturation among the three attributes of hue, lightness, and saturation. Therefore, adjusting the color tone means adjusting the degree of color saturation and lightness (or the degree of shade of color). Further, in the present specification, the "hue" means a hue of colors such as red, green, blue, yellow, magenta, and cyan, and black is also included for convenience. Therefore, for example, magenta having different saturation and lightness can be classified as magenta as having the same hue. Then, adjusting the hue means changing the appearance of the color, that is, changing the color. Further, in the present specification, the "color-developing property" means a property that the color of the water-based ink composition is sufficiently developed in a printed image, and the improvement of the color-developing property can be realized by adjusting the color tone.

The total content of the pigment and the dye is 20% by mass or less, preferably 4% by mass or more and 10% by mass or less, and more preferably 5% by mass or more and 8% by mass or less with respect to the total mass of the aqueous ink composition. .. By setting the total content of the pigment and the dye to 20% by mass or less, it is possible to suppress the deterioration of the ejection property of the water-based ink composition from the inkjet nozzle. The content ratio of the pigment and the dye is not particularly limited, and can be arbitrarily set according to the degree of adjustment of the color tone and / or the hue.

The aqueous ink composition of the present embodiment contains a pigment dispersant for satisfactorily dispersing the pigment. As the pigment dispersant, one that can be used in an inkjet water-based ink composition and that conforms to standards such as the Pharmaceutical Affairs Law can be used. Specific examples thereof include nonionic surfactants and anionic surfactants. Examples of the nonionic surfactant include polyoxy such as polyoxyethylene cured castor oil, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. Examples thereof include ethylene alkyl ether, polysorbate, decaglyceryl oleate and the like. Examples of the anionic surfactant include sodium polyacrylate and the like. These may be used alone or in combination of two or more depending on the type of pigment contained in the water-based ink composition and the like.

When iron tetraoxide is used as the pigment, sodium alginate is suitable as the pigment dispersant. Sodium alginate is adsorbed on iron tetraoxide and functions as a pigment dispersant, thereby imparting an electrical repulsive force due to ionization (ionization) of sodium alginate and a repulsive force due to steric damage to the pigment. Since the iron tetraoxide pigment has magnetism, the cohesive force between the particles is strong, but sodium alginate can prevent the reaggregation of the triiron trioxide pigments due to the repulsive force or the like. As a result, it is possible to provide a pigment dispersion having excellent dispersibility and dispersion stability.

The sodium alginate is not particularly limited as long as it conforms to the standards for pharmaceutical additives and the like specified by the Pharmaceutical Affairs Law, and commercially available products can also be used. Examples of such commercially available products include Kimika Argin ULV-L3 (viscosity 20 mPa · s to 50 mPa · s at 20 ° C. of 10 mass% aqueous solution) and Kimika Argin ULV-1 (viscosity 100 mPa · s at 20 ° C. of 10 mass% aqueous solution). ~ 200 mPa · s), Kimika Argin ULV-3 (viscosity of 10 mass% aqueous solution at 20 ° C, 300 mPa · s ~ 400 mPa · s), Kimika Argin (viscosity of 10 mass% aqueous solution at 20 ° C, viscosity 1800 mPa · s ~ 2300 mPa · s), etc. (Both made by Kimika Co., Ltd.). These sodium alginate can be used alone or in combination of two or more, if necessary.

The mass average molecular weight of sodium alginate is preferably less than 200,000, more preferably less than 100,000, and particularly preferably less than 50,000. By setting the mass average molecular weight to less than 200,000, for example, when the dispersion medium is water, it is possible to prevent the solubility of sodium alginate in water from becoming excessively high. As a result, it is possible to prevent the dispersibility of triiron tetraoxide from being lowered or becoming unable to be dispersed. In addition, the dispersion time can be shortened, and the average dispersed particle size of triiron tetraoxide can be prevented from becoming too large. By setting the mass average molecular weight of sodium alginate to 10,000 or more, the sodium alginate adsorbed on the surface of the pigment can sufficiently exert a repulsive force due to steric damage, etc., thereby preventing the pigments from reaggregating with each other. It can be suppressed.

Here, the value of the mass average molecular weight of sodium alginate means the relative molecular weight obtained by measuring with gel permeation chromatography (GPC) and converting into polyethylene oxide (PEO) / polyethylene glycol (PEG).

The content ratio of sodium alginate to iron trioxide is preferably 0.03 or more and 0.25 or less, more preferably 0.05 or more and 0.2 or less, and 0.08 or more and 0. It is particularly preferably 15 or less. By setting the content ratio of sodium alginate to iron tetraoxide to 0.03 or more, it is possible to prevent the dispersibility of iron tetraoxide from being excessively lowered. On the other hand, by setting the content ratio of sodium alginate to iron tetraoxide to 0.25 or less, while suppressing the viscosity from increasing too much, shearing force or the like is applied to make the aggregated pigment particles finer and dispersed. It is possible to shorten the progress time (dispersion time) up to, and it is possible to suppress the average dispersed particle size of iron tetraoxide from becoming too large.

The content ratio of the pigment to the pigment dispersant is preferably 1: 0.03 to 1: 4 on a mass basis, and more preferably 1: 0.5 to 1: 1. When the content ratio is 1: 0.03 or more, it is possible to prevent a decrease in the dispersibility of the pigment. On the other hand, when the content ratio is 1: 4 or less, it is possible to prevent the ejection property from being lowered due to the adhesion of the nozzle plate.

The water-based ink composition of the present embodiment may contain a fading inhibitor. The fading inhibitor has a function of suppressing the penetration of a dye (hereinafter referred to as "specific dye") having the property of penetrating into the solid preparation with the passage of time due to humidity. Have. Here, as specific dyes, for example, Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1, Blue No. 2, and so on. Examples include copper chlorophyllin sodium and the like. Further, when a specific dye and a dye other than the specific dye are contained, it is possible to suppress their separation. This makes it possible to reduce the occurrence of fading and discoloration of the printed image and maintain good visibility of the printed image. The fading inhibitor also has a function of suppressing photodecomposition of a specific dye by irradiation with light such as natural light. Among the specific dyes, for example, azo dyes such as Red No. 2, Red No. 40 and Red No. 102, and indigoid dyes such as Blue No. 2 are photodecomposed by light irradiation, resulting in fading of the printed image. May be done. However, since the fading inhibitor also suppresses the photodecomposition of such a specific dye, it is possible to reduce the occurrence of light fading in the printed image.

The term "fading" means that the saturation of the printed image is irreversibly reduced as a result of the specific dye permeating the solid preparation due to humidity. Further, "discoloration" means that when a specific dye and another dye are contained, the specific dye permeates the solid preparation due to humidity, and as a result, the specific dye and the other dye are separated from each other, so that the other dye is used. This means that the hue of the above becomes superior to that of the specific dye, and the hue and hue of the entire printed image change irreversibly. "Light fading" means that a specific dye contained in a printed image is photodecomposed due to the influence of natural light or the like, and as a result, the hue and hue of the printed image are irreversibly changed or the printed image is deteriorated. ..

The fading inhibitor is at least one selected from the group consisting of monosaccharides, disaccharides, dextrins and sugar alcohols.

The monosaccharide is not particularly limited, and examples thereof include glucose, galactose, mannose, fructose and the like. Of these, galactose and fructose are preferred in the present invention.

The disaccharide is not particularly limited, and examples thereof include sucrose (sucrose, sugar), lactose (lactose), maltose, trehalose, and palatinose (isomaltulose). Of these, maltose and trehalose are preferred in the present invention.

The dextrins are not particularly limited, and examples thereof include cyclodextrin and the like. The cyclodextrin is not particularly limited, and examples thereof include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and δ-cyclodextrin.

The sugar alcohols are not particularly limited, and examples thereof include mannitol, erythritol, reduced isomaltulose, xylitol, and sorbitol. Further, reduced isomaltulose is a compound obtained by reducing isomaltulose by hydrogenation or the like. Reduced isomaltulose includes α-D-glucopyranocil-1,1-mannitol (hereinafter referred to as "GPM") and α-D-glucopyranocil-1,6-sorbitol (hereinafter referred to as "GPS-6"). It is a mixture with. The mixing ratio of GPM and GPS-6 is not particularly limited, but usually both are mixed in approximately equal molar amounts. Of the sugar alcohols, reduced isomaltulose, xylitol and sorbitol are preferable in the present invention.

Each of the illustrated fading inhibitors can be used alone or in combination of two or more.

The content of the fading inhibitor is 50% by mass or less, preferably 1% by mass to 15% by mass, and more preferably 5% by mass to 10% by mass with respect to the total mass of the aqueous ink composition. In particular, when dextrins or sugar alcohols are used as the fading inhibitor, the content thereof is preferably 20% by mass or less, preferably 1% by mass to 15% by mass, based on the total mass of the aqueous ink composition. , More preferably 3% by mass to 8% by mass. By setting the content of the fading inhibitor to 50% by mass or less, it is possible to prevent the fading inhibitor from precipitating in the aqueous ink composition.

The water-based ink composition of the present embodiment contains water (water as a main solvent). As the water, it is preferable to use pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water from which ionic impurities have been removed. In particular, water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide is suitable because it can prevent the growth of mold and bacteria for a long period of time. Further, the water content is not particularly limited and can be appropriately set as needed.

Further, in the water-based ink composition of the present embodiment, other additives are blended as long as they meet the standards of the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia or the Food Additives Official Regulations. May be good. Additives include surface tension regulators, wetting agents, water-soluble resins, organic amines, surfactants, pH regulators, chelating agents, preservatives, viscosity regulators, defoamers, dispersion stabilizers, anti-reduction agents. , Antioxidants and the like. The contents of these additives are not particularly limited except for the surface tension adjusting agent and the wetting agent, and can be appropriately set as necessary (the contents of the surface tension adjusting agent and the wetting agent will be described later, respectively). .).

The surface tension adjusting agent is not particularly limited as long as it conforms to the standards of the Pharmaceutical Affairs Law and the like, and specific examples thereof include glycerin fatty acid ester and the like. Examples of the glycerin fatty acid ester include caprylic acid decaglyceryl, lauric acid hexaglycerin ester, oleic acid hexaglycerin ester, condensed linolenic acid tetraglycerin ester, fatty acid ester coconut palm, lauric acid decaglyceryl having an HLB of 15 or less, and HLB of 13 Less than decaglyceryl oleate and the like can be mentioned. These may be used alone or in combination of two or more.

As the caprylic acid decaglyceryl, a commercially available product can be used, and as such a commercially available product, for example, Ryoto (registered trademark) polyglycerate CE19D (trade name, manufactured by Mitsubishi Chemical Foods Co., Ltd., HLB value) 15), SY Glister MCA750 (trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB value 16) and the like.

The HLB value is an HLB value obtained by the Griffin method, and means a value obtained by the following formula.
HLB value = 20 × (sum of formulas of hydrophilic groups / molecular weight)
The HLB value is in the range of 0 to 20, and the larger the HLB value, the stronger the hydrophilicity, and the smaller the HLB value, the stronger the hydrophobicity.

As the decaglyceryl laurate, those having an HLB of 15 or less can be used. If the HLB is decaglyceryl laurate exceeding 15, the ejection stability is lowered, such as fading due to clogging of the nozzle of the inkjet head. The lower limit of HLB is preferably 10 or more from the viewpoint of solubility in an aqueous solvent. Further, as a decaglyceryl laurate having an HLB of 15 or less, a commercially available product can be used, and as such a commercially available product, for example, NIKKOL (registered trademark) DECAGLYN 1-L (trade name, Nikko Chemicals (trade name, Nikko Chemicals) Co., Ltd., HLB value 14.5), SY Glister ML-750 (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 14.8) and the like.

As the decaglyceryl oleate, one having an HLB of less than 13 can be used. When the HLB is 13 or more, the ejection stability is lowered, such as blurring due to clogging of the nozzle of the inkjet head. The lower limit of HLB is preferably 10 or more from the viewpoint of solubility in an aqueous solvent. Further, as the decaglyceryl oleate having an HLB of less than 13, a commercially available product can be used, and as such a commercially available product, for example, NIKKOL (registered trademark) DECAGLYN 1-OV (trade name, Nikko Chemicals (trade name, Nikko Chemicals) HLB value 12) manufactured by SY Glister MO-7S (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 12.9) and the like.

As the lauric acid hexaglycerin ester, a commercially available product can be used, and as such a commercially available product, for example, NIKKOL (registered trademark) HEXAGLYN 1-L (trade name, manufactured by Nikko Chemicals Co., Ltd., HLB value) 14.5), SY Glister ML-500 (trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB value 13.5) and the like.

As the oleic acid hexaglycerin ester, a commercially available product can be used, and as such a commercially available product, for example, SY Glyster MO-5S (trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB value 11.6). ) Etc. can be mentioned.

As the condensed linolenic acid tetraglycerin ester, a commercially available product can be used, and examples of such a commercially available product include SY Glister CR-310 (trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.). ..

As the fatty acid ester coconut palm, a commercially available product can be used, and examples of such a commercially available product include tirabazole W-01 (trade name, manufactured by Taiyo Kagaku Co., Ltd.).

The content of the surface tension adjusting agent is preferably in the range of 0.1% by mass to 5% by mass and in the range of 1% by mass to 2% by mass with respect to the total mass of the aqueous ink composition. Is more preferable. When the content of the surface tension adjusting agent is 0.1% by mass or more, when printing is performed by the inkjet method, ejection defects due to poor meniscus formation at the nozzles of the inkjet head are prevented, and the nozzles are clogged. Can be prevented from occurring. As a result, the discharge stability can be improved. On the other hand, when the content of the surface tension adjusting agent is 5% by mass or less, it is possible to prevent adverse effects on discharge due to the insoluble content of the surface tension adjusting agent and poor emulsification.

The wetting agent is not particularly limited as long as it conforms to the standards of the Pharmaceutical Affairs Law and the like, and specific examples thereof include propylene glycol and glycerin.

The amount of the wetting agent added is preferably 1% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, based on the total mass of the aqueous ink composition. By setting the content of the wetting agent to 1% by mass or more, clogging in the vicinity of the nozzle of the inkjet head can be prevented, and the ejection performance can be further improved. On the other hand, by setting the content of the wetting agent to 50% by mass or less, the viscosity of the aqueous ink composition can be appropriately controlled.

The dispersion stabilizer is not particularly limited as long as it conforms to the standards of the Pharmaceutical Affairs Law and the like, and specific examples thereof include disodium malate and the like. The amount of the dispersion stabilizer added is not particularly limited and can be appropriately set as needed.

The water-based ink composition of the present embodiment can be suitably used for ink jet ink. Further, the water-based ink composition of the present embodiment is edible and is a supplement because it uses a material conforming to the standards of the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia or the Food Additives Official Code. It is possible to print directly on the surface of tablets such as. In addition, non-contact printing by the inkjet method is possible even for tablets having poor surface smoothness such as uncoated tablets and OD tablets. Further, since the water-based ink composition of the present embodiment uses a pigment and a dye in combination, an image having excellent light resistance and color development can be directly printed on the surface of a solid preparation such as a drug or a supplement.

The water-based ink composition of the present embodiment is contained at least in the water-based ink for inkjet, which is a final product, and can also be used as the water-based ink for inkjet itself.

(How to print a printed image of a solid product)
The printing method of the printed image in the solid preparation of the present embodiment includes a preparatory step for preparing a water-based ink for inkjet (hereinafter, may be referred to as "water-based ink") containing the above-mentioned water-based ink composition, and a water-based ink. It includes at least a printing step of inkjet printing on a solid formulation using. Further, when the fading inhibitor is added to the water-based ink composition, a fading suppressing step of suppressing fading of the printed image can be included after the printing step.

The water-based ink preparation step may include a step of making a water-based ink composition. The method for producing the water-based ink composition is not particularly limited, and examples thereof include a method in which a pigment composition is first produced and then a dye or the like is added to the pigment composition to produce the pigment composition.

In the preparation of the pigment composition, the mixing method and the order of addition of the pigment, the pigment dispersant, the solvent (dispersion medium) and other additives to be blended as necessary are not particularly limited. For example, at least one pigment, a pigment dispersant, water as a solvent, and the like may be mixed at a time, and the mixed solution may be subjected to a dispersion treatment using a normal disperser.

The distribution time in the distribution process is not particularly limited and can be set as needed. The disperser used in the dispersion treatment of the pigment is not particularly limited as long as it is a generally used disperser. Specific examples thereof include ball mills, roll mills, sand mills, bead mills, paint shakers, nanomizers and the like.

Next, the prepared pigment composition is mixed with an additive such as a dye, water and, if necessary, a fading inhibitor, and the mixture is sufficiently stirred. Further, if necessary, filtration is performed to remove coarse particles and foreign substances that cause clogging. Thereby, the water-based ink composition according to the present embodiment can be obtained.

The mixing method of each material is not particularly limited, and for example, the materials can be sequentially added to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer to perform stirring and mixing. The filtration method is not particularly limited, and for example, centrifugal filtration, filter filtration, or the like can be adopted.

As another method for producing an aqueous ink composition, a pigment, a dye, a pigment dispersant, a solvent (dispersion medium) and other additives to be blended as necessary are mixed at once and then sufficiently stirred. A method of producing is also mentioned.

The printing step is a step of printing an image on the surface of a solid preparation by an inkjet method. More specifically, the water-based ink containing at least the water-based ink composition is ejected as ink droplets from a fine nozzle into the solid preparation, and the ink droplets are adhered to the surface of the solid preparation. The discharge method is not particularly limited, and for example, a known method such as a continuous injection type (charge control type, spray type, etc.), an on-demand type (piezo method, thermal method, electrostatic suction method, etc.) can be adopted. .. Printing conditions such as the amount of ink droplets ejected and the printing speed are not particularly limited, and can be appropriately set as necessary.

In addition, the printing step includes a drying step of drying the ink droplets adhering to the surface of the solid preparation. The drying method is not particularly limited, and in addition to hot air drying, natural drying and the like can be performed. Further, the drying conditions such as the drying time and the drying temperature are not particularly limited, and can be appropriately set according to the amount of ink droplets ejected, the type of the water-based ink composition, and the like.

Further, when the water-based ink composition contains a fading inhibitor, the above-mentioned fading suppressing step is performed after the printing step. The fading suppressing step is a step in which the fading suppressing agent contained in the printed image suppresses the permeation of the specific dye into the solid preparation due to humidity.

The evaluation of the fading suppressing effect is performed, for example, when the image-printed solid preparation is stored for 24 hours in an atmosphere of a temperature of 25 ° C. and a relative humidity of 60%, L ^* a ^* is based on the printed image immediately after printing. b ^* A range of Δa ^* ₁ in the color system of -18 or more, preferably -10 to +10, and more preferably -5 to +5 can be used as one of the evaluation criteria. By setting Δa ^* ₁ to -18 or more, discoloration of the printed image can be reduced and good visibility can be maintained. As a result, even when the product information or the like is printed on the surface of the solid product, it is possible to prevent misidentification of the product information and reduce the occurrence of dispensing mistakes and accidental ingestion. The printed image immediately after printing means a printed image after drying.

Δa ^* ₁ conforms to JIS Z 8730 and is represented by the following general formula (1).
Δa ^* ₁ = a ^* ₁ -a ^* ₀ (1)
(However, a ^* ₀ represents the value in the L ^* a ^* b ^* color system of the printed image in the solid preparation immediately after the printing process, and a ^* ₁ represents the value in the atmosphere of a temperature of 25 ° C. and a relative humidity of 60% for 24 hours. L ^* a ^* b ^* represents the value of the color system of the printed image in the solid preparation after storage.)
The L ^* a ^* b ^* color system is the color space recommended by the International Commission on Illumination (CIE) in 1976, and is the color space called the CIE1976 (L ^* a ^* b ^* ) color system. Meaning, it is stipulated in JIS Z 8730 in the Japanese Industrial Standards.

Further, in the present embodiment, a light fading suppressing step of suppressing photodecomposition of a specific dye may be included. As described above, the fading inhibitor also has a function of suppressing photodecomposition of a specific dye such as an azo dye or an indigoid dye, so that the light fading of the printed image can be reduced.

The evaluation of the light fading suppressing effect is performed based on the printed image immediately after printing, for example, when the printed image on the surface of the solid preparation is irradiated with visible light (wavelength range 380 nm to 750 nm) having an integrated light amount of 1.2 million lpx · hr. , L ^* a ^* b ^* ΔE ^* (ab) in the color system can be 17 or less, preferably 0 to 10, more preferably 0 to 5, as one of the evaluation criteria. By setting ΔE ^* (ab) to 17 or less, it is possible to reduce the light fading of the printed image and maintain good visibility. As a result, even when the product information or the like is printed on the surface of the solid product, it is possible to prevent misidentification of the product information and reduce the occurrence of dispensing mistakes and accidental ingestion. The printed image immediately after printing means a printed image after drying, as described above.

ΔE ^* (ab) conforms to JIS Z8781 and is represented by the following general formula (2).
ΔE ^* (ab) = ((ΔL ^* ₂ ) ² + (Δa ^* ₂ ) ² + (Δb ^* ₂ ) ² ) ^1/2 (2)
However, ΔL ^* ₂ , Δa ^* ₂ and Δb ^* ₂ are represented as follows, respectively.
ΔL ^* ₂ = L ^* ₂ -L ^* ₀
(L ^* ₀ represents the brightness of the L ^* a ^* b ^* color system immediately after the printing process in the printed image of the solid preparation, and L ^* ₂ represents the visible light with an integrated light amount of 1.2 million lpx · hr in the printed image of the solid preparation. L ^* a ^* b ^* represents the brightness of the color system after irradiation.)
Δa ^* ₂ = a ^* ₂ -a ^* ₀
(A ^* ₀ represents the value of the L ^* a ^* b ^* color system immediately after the printing step in the printed image of the solid preparation, and a ^* ₂ is visible of the integrated light amount of 1.2 million lx · hr in the printed image of the solid preparation. L ^* a ^* b ^* represents the value of the color system after irradiation with light.)
Δb ^* ₂ = b ^* ₂ -b ^* ₀
(B ^* ₀ represents the value of the L ^* a ^* b ^* color system immediately after the printing process in the printed image of the solid preparation, and b ^* ₂ represents the visible amount of integrated light of 1.2 million lx · hr in the printed image of the solid preparation. L ^* a ^* b ^* represents the value of the color system after irradiation with light.)

(Solid product)
In the present specification, the "solid preparation" means to include a food preparation and a pharmaceutical preparation, and the form of the solid preparation includes, for example, OD tablets (orally disintegrating tablets), uncoated tablets, FC (film-coated) tablets, and sugar-coated tablets. Such as tablets or capsules. Moreover, the solid preparation may be used for pharmaceutical products or may be used for foods. Examples of tablets for food use include health foods such as tablets and supplements.

A printed image consisting of a dry film directly printed by an inkjet recording method is formed on the surface of the solid preparation using a water-based ink containing the water-based ink composition. The dry film is at least composed of the pigment and the dye contained in the water-based ink composition.

In the solid preparation of the present embodiment, since the printed image made of the dry film has excellent light resistance, it is possible to prevent deterioration of the image of various information such as product information, for example. Further, since the printed image is excellent in color development, it is possible to improve the distinguishability to the user. As a result, the solid preparation of the present embodiment maintains good visibility for a long period of time, and makes it possible to prevent dispensing mistakes and accidental ingestion.

As described above, the fading inhibitor suppresses the permeation of the specific dye into the solid preparation due to the ambient humidity, and this effect is particularly effective when the solid preparation is a sugar-coated tablet or an FC tablet. Is. Examples of the sugar-coated tablet in which the fading inhibitor of the present invention is particularly likely to exert its effect include those having a sugar-coated layer made of sucrose (sucrose), maltitol, or the like. The content of sucrose or maltitol in the sugar-coated layer is not particularly limited and can be appropriately set as needed. In addition, examples of FC tablets in which the fading inhibitor of the present invention is particularly likely to exert its effect include those in which the film coat is made of a cellulosic polymer compound such as hydroxypropylmethylcellulose.

Hereinafter, preferred embodiments of the present invention will be described in detail by way of illustration. However, the materials, contents, etc. described in the following examples are not limited to those of the present invention unless otherwise specified. In addition, each material of the water-based ink composition for inkjet conforms to the standards of the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia, or the official standard of food additives.

(Example 1)
In this embodiment, first, 6 g of iron tetraoxide (manufactured by Kasei Co., Ltd.) as a pigment, 0.6 g of sodium alginate (manufactured by Kimika Co., Ltd.) as a pigment dispersant, and 23.4 g of ion-exchanged water are placed in a container. The mixture was mixed in the container, and the mixed solution in the container was dispersed by a disperser (paint shaker, manufactured by Asada Iron Works Co., Ltd.) to prepare a pigment dispersion (the mixing ratio of the pigment, the pigment dispersant and the ion-exchanged water was 1: 0.1: 3.9). Subsequently, 2 g of decaglyceryl monocaprylate (trade name: SY Glister MCA750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) as a surface tension adjuster and 30 g of propylene glycol as a wetting agent were added to the produced pigment dispersion. Further, 37.7 g of ion-exchanged water was added so that the total content of the ion-exchanged water was 61.1 g, and the pigment composition according to this example was prepared. The pigment composition had a reddish black color.

Further, 0.3 g of Blue No. 2 (manufactured by Daiwa Kasei Co., Ltd.) was added to this pigment composition, and the solid of Blue No. 2 was dissolved without precipitating. As a result, an aqueous ink composition in which black iron oxide was dispersed and Blue No. 2 was dissolved was prepared (see Table 1).
(Example 2)
In this example, 9.2 g of Blue No. 1 was added as the dye instead of Blue No. 2. The blending ratio of each composition other than these was changed as shown in Table 1, and the water-based ink composition according to this example was prepared by the same method as in Example 1 (see Table 1).

(Example 3)
In this example, the content of iron tetraoxide was changed to 1.2 g. Further, as a dye, 0.01 g of Blue No. 1 was added instead of Blue No. 2. The blending ratio of each composition other than these was changed as shown in Table 1, and the water-based ink composition according to this example was prepared by the same method as in Example 1 (see Table 1).

(Example 4)
In this example, the content of iron tetraoxide was changed to 0.6 g. Further, as a dye, 0.005 g of Blue No. 1 was added instead of Blue No. 2. The blending ratio of each composition other than these was changed as shown in Table 1, and the water-based ink composition according to this example was prepared by the same method as in Example 1 (see Table 1).

(Comparative Examples 1 to 4)
In Comparative Examples 1 to 4, the blending ratio of each composition was changed as shown in Table 1, and no dye was added. Other than these, the water-based ink compositions according to Comparative Examples 1 to 4 were prepared by the same method as in Example 1.

(Comparative Example 5)
In this comparative example, the blending ratio of each composition was changed as shown in Table 1. In addition, the amount of the dye Blue No. 2 added was changed to 0.6 g. A water-based ink composition according to this comparative example was prepared by the same method as in Example 1 except for them.

(Example 5)
In this embodiment, first, 8 g of red No. 40 aluminum lake (manufactured by Saneigen Co., Ltd.) as a pigment, sodium polyacrylic acid as a pigment dispersant (trade name: TEGO (registered trademark) Dispers 715W, manufactured by Evonik), 6 g of mass average molecular weight 3000), 2 g of disodium malate (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersion stabilizer, and 44 g of ion-exchanged water are mixed in a container, and the mixed solution is a disperser (paint shaker, Asada Iron Works Co., Ltd.). A pigment dispersion was prepared (the compounding ratio of the pigment, the pigment dispersant, the dispersion stabilizer and the ion-exchanged water was 1: 0.75: 0.25: 5.5). Subsequently, 30 g of propylene glycol as a wetting agent and 2 g of decaglyceryl monocaprylate (trade name: SY Glister MCA750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) as a surface tension adjusting agent were added to the produced pigment dispersion. Further, 6.9 g of ion-exchanged water was added so that the total content of the ion-exchanged water was 50.9 g, and the pigment composition according to this example was prepared.

To this pigment composition, 0.1 g of Blue No. 1 and 1 g of Yellow No. 4 were further added, and the solids of Blue No. 1 and Yellow No. 4 were dissolved without precipitating. As a result, a water-based ink composition in which Red No. 40 aluminum lake was dispersed and Blue No. 1 and Yellow No. 4 were dissolved was prepared (see Table 2).

(Comparative Example 6)
In this comparative example, the blending ratio of each composition was changed as shown in Table 2, and no dye was added. A water-based ink composition according to this comparative example was prepared by the same method as in Example 4 except for them.

(Comparative Example 7)
In this comparative example, the blending ratio of each composition was changed as shown in Table 2. Further, the addition amount of the dye Blue No. 1 was changed to 1.2 g, and the addition amount of the yellow No. 4 was changed to 12 g. A water-based ink composition according to this comparative example was prepared by the same method as in Example 4 except for them.

(Example 6)
In this embodiment, first, 8 g of yellow No. 4 aluminum lake (manufactured by Saneigen Co., Ltd.) as a pigment, sodium polyacrylic acid as a pigment dispersant (trade name: TEGO (registered trademark) Dispers 715W, manufactured by Evonik), 6 g of mass average molecular weight 3000), 2 g of disodium malate as a dispersion stabilizer (manufactured by Wako Pure Chemical Industries, Ltd.) and 44 g of ion-exchanged water are mixed in a container, and the mixed solution is a disperser (paint shaker, Asada Iron Works Co., Ltd.). A pigment dispersion was prepared (the compounding ratio of the pigment, the pigment dispersant, the dispersion stabilizer and the ion-exchanged water was 1: 0.75: 0.25: 5.5). Subsequently, 30 g of propylene glycol as a wetting agent and 2 g of decaglyceryl monocaprylate (trade name: SY Glister MCA750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) as a surface tension adjusting agent were added to the produced pigment dispersion. Further, 7.2 g of ion-exchanged water was added so that the total content of the ion-exchanged water was 51.2 g, and the pigment composition according to this example was prepared.

To this pigment composition, 0.5 g of Red No. 102 and 0.3 g of Blue No. 1 were further added, and the solids of Red No. 102 and Blue No. 1 were dissolved without precipitating. As a result, a water-based ink composition was prepared in which Yellow No. 4 aluminum lake was dispersed and Red No. 102 and Blue No. 1 were dissolved (see Table 3).

(Comparative Example 8)
In this comparative example, the blending ratio of each composition was changed as shown in Table 3, and no dye was added. A water-based ink composition according to this comparative example was prepared by the same method as in Example 5 except for them.

(Comparative Example 9)
In this comparative example, the blending ratio of each composition was changed as shown in Table 3. Further, the amount of red No. 102 added as a dye was changed to 7 g, and the amount of blue No. 1 added was changed to 4.2 g. A water-based ink composition according to this comparative example was prepared by the same method as in Example 5 except for them.

(Example 7)
In Example 7, the blending ratio of each composition was changed as shown in Table 4. In addition, 1 g of reduced isomaltulose was added as a fading inhibitor. Other than these, the water-based ink composition according to this example was prepared by the same method as in Example 1.

(Discharge stability)
Using the water-based inks composed of the water-based ink compositions of Examples 1 to 6 and Comparative Examples 1 to 9, printing was performed on one side of the uncoated lock by an inkjet method, and an image was formed on the surface of the uncoated tablet.

Printing was performed by a single-pass (one-pass) method using an inkjet printer (KC 600 dpi head, medium-speed printing jig). The printing was performed in an environment where the temperature was 25 ° C. and the relative humidity was 40%. Further, after printing, hot air was directly blown by a dryer to sufficiently dry the printed surface.

The ejection stability was evaluated based on whether or not nozzle omission or faintness was observed in the printed image when the inkjet printer was stopped after ejecting the water-based ink composition from the head and then reprinted. The results are shown in Tables 1 to 3. ◯ in the table means that no nozzle omission or faintness was observed. X means a case where at least one of nozzle omission or faintness occurs during printing. Note that nozzle omission means that ink droplets (droplets) made of an aqueous ink composition are not ejected from a nozzle in which clogging has occurred. Blurring means blurring of an image in the early stages of printing.

As can be seen from Tables 1 to 3, it was confirmed that the water-based ink compositions of Examples 1 to 6, Comparative Examples 1 to 3, Comparative Example 6 and Comparative Example 8 all showed good ejection stability. On the other hand, in Comparative Examples 4 and 5, the viscosity of the water-based ink composition increased due to the pigment content of more than 10% by mass, and the water-based ink composition could not be ejected from the inkjet head. Further, in the water-based ink compositions of Comparative Examples 7 and 9, when the content of the dye was more than 10% by mass, a solid of the dye was deposited, and as a result, ejection failure from the inkjet nozzle occurred. From the above, from the viewpoint of ejection stability, the water-based ink composition for inkjet has a pigment and dye content of 10% by mass or less and is dissolved to such an extent that the dye does not precipitate. It was confirmed that it is suitable as a water-based ink for inkjet.

(Tone and hue)
The color tone and hue of the images printed on the surface of the uncoated tablet using the water-based inks composed of the water-based ink compositions of Examples 1 to 6 , Comparative Examples 1 to 3, Comparative Example 6 and Comparative Example 8 were evaluated, respectively. The evaluation criteria are as follows. Since printing of Comparative Examples 4, 5, 7 and 9 could not be performed due to poor ejection, the color tone and the like of the printed image were not evaluated. The results are shown in Tables 1 to 3.
◯: It can be visually judged that the color tone and / or the hue has changed Δ: It can be visually judged that the color tone and / or the hue has changed, but the effect is small compared to ○ ×: The color tone and the hue are I can't visually judge that it has changed

As can be seen from Table 1, in the aqueous ink compositions of Examples 1 to 3, comparison using only the black iron oxide pigment by adding the dye of Blue No. 1 or Blue 2 to adjust the color tone and hue. Compared with Example 1, it was possible to improve to black without redness. In particular, with respect to the water-based ink compositions of Examples 1 and 2, the image could be printed in a black color having a good color tone, and the visibility of the printed image could be improved.

Further, as can be seen from Table 2, in the aqueous ink composition of Example 5 , comparison using only the lake pigment of red No. 40 aluminum lake by adding blue No. 1 and yellow No. 4 to adjust the hue. Compared with Example 6, it was possible to adjust the color to good black, and it was possible to improve the visibility of the printed image.

Further, as can be seen from Table 3, in the aqueous ink composition of Example 6 , by adding red No. 102 and blue No. 1 to adjust the hue, only the lake pigment of yellow No. 4 aluminum lake is used as the colorant. Compared with Comparative Example 8 used, the hue could be adjusted to greenish black, and the visibility of the printed image could be improved.

(Evaluation of light fading inhibitory property)
The fading inhibitory properties of the water-based ink compositions of Examples 1 and 7 were evaluated by performing the following tests in an environment of 60% relative humidity. That is, for the uncoated tablets (samples) after inkjet printing with the water-based ink compositions according to Examples 1 and 7, using a color difference meter (model number: VSS7700, manufactured by Nippon Denshoku Kogyo Co., Ltd.), L ^* a. ^* B ^* L ^* ₀ , a ^* ₀ , and b ^* ₀ in the color system were measured (in Table 5, the values of L ^* , a ^* , and b ^* at the integrated light amount of 0 lex · hr). The measurement was performed at two points in each of the printed images of Examples 1 and 7.

Subsequently, using a light stability test device (manufactured by Nagano Science Co., Ltd.) conforming to the ICH guidelines, the printed sample stored in a closed glass bottle was irradiated with light. The integrated light intensity at this time was 1.2 million lux · hr (for 50 days in terms of indoor fluorescent lamps). After that, L ^* ₂ , a ^* ₂ , and b ^* ₂ in the L ^* a ^* b ^* color system of each sample were measured again using the color difference meter (in Table 5, the integrated light amount was 1.2 million lux · hr. The values of L ^* , a ^* , and b ^* in.). The measurement was performed at the same locations as in the case where the integrated light intensity was 0 lpx · hr in each of the printed images of Examples 1 and 7, respectively. The results are shown in Table 5.

In addition, ΔE ^* (ab) ₂ , ΔL ^* ₂ , Δa ^* ₂ , and Δb ^* ₂ shown in each table were calculated by the following general formulas, respectively.
ΔE ^* (ab) ₂ = ((ΔL ^* ₂ ) ² + (Δa ^* ₂ ) ² + (Δb ^* ₂ ) ² ) ^1/2
ΔL ^* ₂ = L ^* ₂ -L ^* ₀
Δa ^* ₂ = a ^* ₂ -a ^* ₀
Δb ^* ₂ = b ^* ₂ -b ^* ₀

As shown in Table 5, in the sample of Example 1, the color difference ΔE ^* (ab) ₂ of the printed image printed on the uncoated tablet is larger than that immediately after printing, and the printed image fades. It was confirmed that there was.

On the other hand, in the sample of Example 7, an increase in the color difference ΔE ^* (ab) ₂ of the printed image printed on the uncoated tablet could be significantly suppressed. As a result, it was confirmed that in Example 7, the photodecomposition of the blue No. 2 indigoid dye in the printed image could be reduced, and the light fading could be reduced. The "pseudo color" shown in Table 5 means that the color of the image printed on the unlock is replaced with another color.

Claims (11)

An inkjet water-based ink composition used for printing on solid formulations.
Contains at least one edible pigment and one edible dye,
The pigment is contained in the water-based ink composition for inkjet in a dispersed state.
The dye is dissolved and contained in the water-based ink composition for inkjet within a range in which the dye does not precipitate.
Each of the contents of the pigment and the dye is 10% by mass or less with respect to the total mass of the water-based ink composition for inkjet .
The dye is a color tone adjuster and / or a hue adjuster.
A water-based ink composition for inkjet , wherein the pigment is at least one selected from the group consisting of red iron sesquioxide, yellow iron sesquioxide, iron tetraoxide, and lake pigment . An inkjet water-based ink composition used for printing on solid formulations.
Contains at least one edible pigment and one edible dye,
The pigment is contained in the water-based ink composition for inkjet in a dispersed state.
The dye is dissolved and contained in the water-based ink composition for inkjet within a range in which the dye does not precipitate.
Each of the contents of the pigment and the dye is 10% by mass or less with respect to the total mass of the water-based ink composition for inkjet.
The dye is a color tone adjuster and / or a hue adjuster.
From the group consisting of red No. 2, red No. 3, red No. 4, red No. 40, red No. 102, yellow No. 4, yellow No. 5, green No. 3, blue No. 1, blue No. 2, and natural dye. A water-based ink composition for inkjet, which is at least one selected. An inkjet water-based ink composition used for printing on solid formulations.
Contains at least one edible pigment and one edible dye,
The pigment is contained in the water-based ink composition for inkjet in a dispersed state.
The dye is dissolved and contained in the water-based ink composition for inkjet within a range in which the dye does not precipitate.
Each of the contents of the pigment and the dye is 10% by mass or less with respect to the total mass of the water-based ink composition for inkjet.
Further, it contains at least one fading inhibitor selected from the group consisting of monosaccharides, disaccharides and sugar alcohols.
An inkjet water-based ink composition in which the content of the fading inhibitor is 50% by mass or less based on the total mass of the inkjet water-based ink composition. The water-based ink composition for inkjet according to claim 3 , wherein the dye is a color tone adjuster and / or a hue adjuster. The lake pigment is selected from the group consisting of Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1 and Blue No. 2. The water-based ink composition for inkjet according to claim 1, which is a lake of at least one dye. The pigment is at least one selected from the group consisting of red iron sesquioxide, yellow iron sesquioxide, iron trioxide, carbon black, and lake pigments.
Further, the lake pigment is composed of a group consisting of Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1 and Blue No. 2. The water-based ink composition for inkjet according to any one of claims 2 to 4, which is a lake of at least one selected dye. The dyes are Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Green No. 3, Blue No. 1, Blue No. 2, Chlorophylline dyes and natural dyes. The water-based ink composition for inkjet according to any one of claims 1 , 3, 4 or 5 , which is at least one selected from the group consisting of. The water-based ink jet composition according to any one of claims 1 to 7 , wherein the content of the pigment is 0.1% by mass or more with respect to the total mass of the water-based ink jet composition. The water-based ink jet composition according to any one of claims 1 to 8 , wherein the content of the dye is 0.01% by mass or more with respect to the total mass of the water-based ink jet composition. Further, it contains at least one fading inhibitor selected from the group consisting of monosaccharides, disaccharides, dextrins and sugar alcohols.
The water-based ink jet composition according to any one of claims 1 , 2 or 5 , wherein the content of the fading inhibitor is 50% by mass or less with respect to the total mass of the water-based ink jet composition. A solid pharmaceutical product having a dry film of water-based ink for inkjet on its surface.
The water-based inkjet ink is a solid preparation containing the water-based inkjet ink composition according to any one of claims 1 to 10 .