JP2019123840A - Water-based ink composition for inkjet and solid formulation - Google Patents

Abstract

To provide a water-based ink composition for inkjet, capable of printing an image with easily adjusting color tone or color phase to a solid formulation such as pharmaceuticals or foods without impairing discharge property, and the solid formulation.SOLUTION: The water-based ink composition for inkjet is a water-based ink composition for inkjet used for printing to a solid formulation, containing at least one kind each of an edible pigment and an edible dye, the pigment is contained at a dispersion state in the water-based ink composition for inkjet, the dye is contained by dissolution in the water-based ink composition for inkjet in a range that the dye is not deposited, and contents of the pigment and the dye are 10 mass% or less based on all mass of the water-based ink composition for inkjet respectively.SELECTED DRAWING: None

Description

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

  Ink-jet inks used for printing on solid preparations (for example, tablets, capsules, etc.) such as pharmaceuticals and foods are classified into a dye ink using a dye and a pigment ink (for example, patent document 1) in which a pigment is dispersed. It is divided roughly. In general, dye inks have the advantage that they have various colors and are excellent in vivid color developability, but they have the disadvantage of being easily discolored and inferior in light resistance. On the other hand, pigment inks have the advantage of being hardly faded compared to dye inks and having excellent light resistance, but have the disadvantage of being inferior in color development to dye inks. Therefore, from the viewpoint of printing an image excellent in 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, the pigment ink conforms to the standards of pharmaceutical additives, Japanese Pharmacopoeia or food additives official regulations stipulated by the Pharmaceutical Affairs Law in Japan. Needs to be done. Furthermore, in Japan, there are pigments that conform to the standards of pharmaceutical additives and the like specified by the Pharmaceutical Affairs Law, but their use in medicines and the like is not permitted in some countries. Therefore, in each country, the pigment ink which can be printed on a solid preparation is limited, and there is a problem that it is difficult to freely change the color tone or hue of the printed image according to the color of the solid preparation. . In addition, it is also difficult to print an image with excellent visibility because pigment ink is inferior in color development to dye ink. Although it is conceivable to increase the content of the pigment in order to improve the color developability, in that case, there is a problem that the dischargeability in the ink jet head is reduced, and it becomes difficult to print a good image.

JP, 2015-140414, A

  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 the hue and print the image on solid preparations such as pharmaceuticals and foods without impairing the ejection property. An ink jet aqueous ink composition and a solid preparation.

  The aqueous ink composition for inkjet according to the present invention is an aqueous ink composition for inkjet used for printing on a solid preparation in order to solve the above-mentioned problems, which comprises an edible pigment, an edible dye and The pigment is contained in a dispersed state in the aqueous ink composition for ink jet, and the dye is contained by dissolving in the aqueous ink composition for ink jet as long as the dye does not precipitate. The content of each of the pigment and the dye is 10% by mass or less based on the total mass of the aqueous ink composition for inkjet.

  In general, since an ink containing a pigment (hereinafter referred to as "pigment ink") is excellent in light resistance, the color of printed images fades with time, as compared to an ink containing a dye (hereinafter referred to as "dye ink"). And the progress of discoloration can be suppressed. However, since the pigment is inferior in coloring property to the dye, when the image is printed on a tablet or capsule such as a medicine using a pigment ink, the visibility of the image may be lowered.

  On the other hand, the aqueous ink composition for ink jet recording (hereinafter sometimes referred to as "aqueous ink composition") of the above constitution contains at least one pigment and at least one dye, so that color development is maintained while maintaining good light resistance. Enables the printing of excellent images. In the above-mentioned configuration, the pigment is present in a dispersed state, and is dissolved and present in the range in which the dye does not precipitate in the aqueous ink composition. Furthermore, the content of each of the pigment and the dye is 10% by mass or less based on the total mass of the aqueous ink composition. Therefore, in the water-based ink composition having the above-described structure, the dischargeability from the ink jet nozzle can be well maintained.

  In the above-mentioned configuration, it is preferable that the dye is contained as a color tone adjusting agent and / or a color tone adjusting agent.

  For example, in an aqueous ink composition using only a pigment as a colorant, when the pigment is excessively added to improve the color developability of the aqueous ink composition, the dischargeability from the ink jet nozzle decreases, and the aqueous ink The flightability of the composition may be reduced. However, as described above, by using a dye as a color tone adjusting agent, it is possible to adjust the color tone of the aqueous ink composition, for example, only by adding a small amount of the dye. As a result, it is possible to adjust the color tone while suppressing the decrease in the dischargeability of the aqueous ink composition, and to improve the color development of the printed image.

  Further, as in the above-mentioned constitution, by using a dye as a hue adjusting agent, it is also possible to adjust the hue of the aqueous ink composition. That is, since the aqueous ink composition of the present invention is intended for printing on a solid preparation such as a pharmaceutical product, the components contained in the aqueous ink composition include the pigment, the pharmaceutical additives defined by the Pharmaceutical Affairs Law, the Japanese Pharmacopoeia or It is necessary to meet the standards of the Food Additives Standards. Therefore, the pigment applicable to the printing of the solid preparation is limited, and the adjustment of the hue of the aqueous ink composition may not be easy. 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. However, by including the dye as in the above-mentioned configuration, the hue of the aqueous ink composition can be easily adjusted, and the aqueous ink is made to correspond to the color of the surface of the solid preparation to be subjected to image formation. The hue of the composition can be easily adjusted.

  Furthermore, as in the above-mentioned constitution, the dye can also be used as both a color tone adjusting agent and a color tone adjusting agent. In this case, it is possible to simultaneously adjust the color tone and hue of the aqueous ink composition. Thus, for example, by changing the hue of the aqueous ink composition to a hue different from that of the pigment, the visibility of the printed image is improved, and the color tone of the aqueous ink composition is improved by adjusting the color tone. be able to.

  In the above configuration, the pigment is at least one selected from the group consisting of red ferric oxide, yellow ferric oxide, ferric trioxide, carbon black, and a lake pigment, and the lake pigment is further selected from the group consisting of , Red 2, Red 3, Red 4, Red 40, Red 102, Yellow 4, Yellow 5, Yellow 3, Green 1, Blue 1 and Blue 2 at least one selected from the group consisting of It is preferable that the dye is a rake.

  Further, in the above-mentioned constitution, the dye is composed of Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Yellow No. 4, Yellow No. 5, Yellow No. 3, Green No. 3, Blue No. 1, Blue No. It is preferably at least one selected from the group consisting of chlorophyllins dyes and natural dyes.

  In the above-mentioned configuration, the content of the pigment is preferably 0.1% by mass or more based on the total mass of the aqueous ink composition for inkjet. By making the content of the pigment 0.1% by mass or more, the color tone can be changed when combined with the dye.

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

  In the above-mentioned configuration, the composition further includes 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 composition of the aqueous ink for inkjet 50 mass% or less may be sufficient with respect to the total mass of a thing.

  For example, dyes such as Red No. 2 have the property of permeating solid preparations with the passage of time due to humidity. On the other hand, monosaccharides, disaccharides, dextrins and sugar alcohols exhibit the function of suppressing the permeation of such a dye into a solid preparation caused by humidity in a printed image. Therefore, the fall of the saturation of the printing image resulting from the penetration to the solid preparation of dye can be suppressed, and generation | occurrence | production of discoloring can be reduced. In addition to these dyes, in the case of an image printed using other dyes comprising natural dyes and the like, it is also possible to prevent these dyes from separating from the other dyes and penetrating into the solid preparation. it can. As a result, discoloration of the printed image can also be reduced.

  In addition, azo dyes such as Red No. 2 and the like, and indigoid dyes such as Blue No. 2 and the like have the property of being decomposed (photo-degraded) by irradiation with light, and thereby the printed image becomes light faded. There is. However, the antifading agent also exerts the function of suppressing the photodegradation to such a dye. Therefore, in the water-based ink composition having the above-described structure, the printed image can be reduced from being deteriorated due to the occurrence of light fading.

  In the above configuration, the fading inhibitor can be sufficiently dissolved in the aqueous ink composition by setting the content of the fading inhibitor to 50% by mass or less based on the total mass of the aqueous ink composition. Precipitation can be prevented.

  The solid preparation according to the present invention is a solid preparation having a dry film of an aqueous ink for ink jet on the surface to solve the above-mentioned problems, and the aqueous ink for ink jet is the aqueous ink composition for ink jet Is included.

  According to the above configuration, at least one of the pigment and the dye is contained in the dried film of the inkjet ink, so the printed image formed by the dried film is excellent in color development while maintaining good light resistance. ing. Therefore, if it is a solid preparation of the above-mentioned composition, fading of a printing picture which a dry film forms can be reduced, and it can control that a visibility of a printing picture falls with change over time. Moreover, since it is excellent also in coloring property, for example, when product information is printed, the solid formulation which can prevent a dispensing mistake, accidental ingestion, etc. can be provided.

  According to the aqueous ink composition for ink jet recording of the present invention, since it contains at least one pigment and at least one dye, in the image printed on the surface of the solid preparation using the aqueous ink composition for ink jet, both light resistance and color developability Can be improved. In addition, by appropriately changing the type and the blending ratio of the pigment and the dye, it is possible to print an image on a solid preparation while easily adjusting the color tone and the hue without impairing the dischargeability.

(Water-based ink composition for inkjet)
The aqueous ink composition for inkjet according to the present embodiment (hereinafter, referred to as “aqueous ink composition”) will be described below.
The aqueous ink composition of the present embodiment is a composition containing at least one pigment and one dye as colorants, and the main solvent being water. In addition, the aqueous ink composition of the present embodiment can be made edible by using a material conforming to the standard of the pharmaceutical additive, the Japanese Pharmacopoeia, or the official document of the food additive prescribed by the Pharmaceutical Affairs Law. It can be used suitably for recording of an image etc. by an inkjet system.

  Here, the term "edible" as used herein means a substance approved for oral administration as a pharmaceutical product or pharmaceutical additive, and / or a substance recognized as a food or food additive. Further, in the present specification, the "ink jet system" means a system in which an aqueous ink composition is discharged as droplets from a fine ink jet 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 ferric oxide, yellow ferric oxide, triiron trioxide (black iron oxide), carbon black, and lake pigment There is at least one type.

  The lake pigment means a pigment obtained by laked a dye soluble in a main solvent, and more specifically, the dye is adsorbed to the precipitant by adding a precipitant such as a metal salt, and the insoluble salt (insoluble It is a precipitate precipitated as fine particles). No particular limitation is imposed on the dye that exhibits swayability to the main solvent, but preferably, Red No. 2, Red No. 3, Red No. 4, Red No. 40, Red No. 102, Red No. 102, Yellow No. 4, Yellow No. 5, Yellow No. 3 And at least one selected from the group consisting of Blue No. 1 and Blue No. 2.

  More specific examples of the lake pigment 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, yellow No. 4 Barium lake, yellow No. 4 zirconium 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 may be contained alone or in mixtures of two or more in the aqueous ink composition. The hue of the aqueous ink composition can be adjusted by mixing two or more kinds of pigments. The details of the "hue" will be described later.

  The pigment is present in the aqueous ink composition in a dispersed state. The particle size (D50) of 50% in cumulative particle size in the volume-based cumulative 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. In addition, the particle size (D99) of 99% in cumulative particle size in the volume-based cumulative 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, it is possible to prevent the deterioration of the dispersion stability, the light resistance and the discharge stability, and to prevent the reduction of the printing density. On the other hand, by setting D50 to 200 nm or less, separation and sedimentation of the pigment can be prevented, and dispersion stability can be maintained. When a plurality of pigments are contained in the aqueous ink composition, D50 and D99 of each pigment 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-EX 150 (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, based on the total mass of the aqueous ink composition for inkjet. It is particularly preferable that the content is 8% by mass or more. By making content of a pigment 0.1 mass% or more, it can suppress that the light resistance of a printing image falls. In addition, it makes it possible to change the color tone and / or hue by combination with the dye. In addition, the fall of discharge (stable) property of the water-based ink composition in an inkjet head can be suppressed by content of a pigment being 10 mass% or less. Moreover, when multiple types of pigments are contained in the aqueous 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 preferably red 2, red 4, red 40, red 102, yellow 4, yellow 5, yellow 5, green 3, blue 1. At least one selected from the group consisting of chlorophyllins dyes and natural dyes.

  The chlorophyllins pigment is not particularly limited, and examples thereof include sodium iron chlorophyllin, sodium copper chlorophyllin, sodium chlorophyllin and the like. Moreover, it does not specifically limit as a natural pigment, For example, a cochineal pigment, a cocoa pigment, a caramel pigment etc. are mentioned.

  The dye is present in solution in the aqueous ink composition. Also, the dye is present in such a range that the solid does not precipitate in the aqueous ink composition. Although the content of the dye depends on the type thereof, it is preferably 0.01% by mass or more, and more preferably 0.1% by mass to 10% by mass, with respect to 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 plural kinds of dyes are contained in the aqueous 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 adjusting agent and / or a color tone adjusting agent. For example, in an aqueous ink composition using only a pigment as a colorant, it is conceivable to design change the chemical structure, such as changing the side chain of the pigment, as a method of adjusting the color tone and / or the color hue. However, in order to be able to print on solid preparations such as pharmaceuticals and foods, it is necessary to conform to the standards such as pharmaceutical additives specified by the Pharmaceutical Affairs Law, and the chemical structure of the pigment in the form conforming to the standards Design change is not easy. On the other hand, in the present invention, among the dyes conforming to the standard such as pharmaceutical additives defined in the Pharmaceutical Affairs Law, any dye may be added as a color tone adjusting agent and / or a color tone adjusting agent to obtain the chemical structure of the pigment. The color tone and / or hue of the aqueous ink composition can be easily adjusted without any design change. In addition, there are pigments that meet the criteria such as pharmaceutical additives specified in the Pharmaceutical Affairs Law in Japan, but some countries do not allow their use for medicine etc. In such cases, the desired color tone And it becomes difficult to print an image of hue. However, in the present invention, it becomes possible to adjust to the desired color tone and color only by adding the dye as a color tone adjusting agent and / or a color tone adjusting agent to the pigment recognized for use in the country. . 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 the printed image according to the color of the solid preparation, and the degree of freedom is high.

  Also, for example, when an excessive amount of pigment is added to an aqueous ink composition using only a pigment as a colorant in order to improve the color developability of the aqueous ink, or to adjust the hue of the aqueous ink composition, In the case of mixing a plurality of pigments having different hues, the viscosity of the aqueous ink composition may be too high, and the dischargeability from the ink jet nozzle may be reduced. However, when a dye is used as a color tone modifier, for example, the addition of a small amount of the dye makes it possible to adjust the color tone of the aqueous ink composition. As a result, the color development can be improved while suppressing the decrease in the flightability of the aqueous ink composition.

  Depending on the combination with the pigment, it is also possible to make the dye simultaneously function as a tone control agent and a hue control agent. In this case, the color tone and hue of the aqueous ink composition can be simultaneously adjusted.

  In the present specification, “tone” means a system of colors represented by a combination of lightness and saturation, out of three attributes of hue, lightness, and saturation. Therefore, adjusting the color tone means adjusting the degree of saturation and lightness of the color (or the degree of light and shade of the color). Further, in the present specification, “hue” means the appearance of colors such as red, green, blue, yellow, magenta, and cyan, and includes black for convenience. Therefore, for example, magentas having different saturation and lightness can be classified as magenta as the same hue. And adjusting the hue means changing the appearance of the color, that is, changing the color. Furthermore, in the present specification, “chromogenic property” means the property that the color of the aqueous ink composition has sufficient color in a printed image, and the improvement of the chromogenic 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 to 10% by mass, and more preferably 5% by mass to 8% by mass, based on the total mass of the aqueous ink composition. . By reducing the total content of the pigment and the dye to 20% by mass or less, it is possible to suppress the decrease in the dischargeability of the aqueous ink composition from the ink jet nozzle. The content ratio of the pigment to the dye is not particularly limited, and can be arbitrarily set according to the degree of adjustment of color tone and / or hue.

  The aqueous ink composition of the present embodiment contains a pigment dispersant for well dispersing the pigment. As a pigment dispersing agent, it can be used for the inkjet water-based ink composition, and what adapts to the criteria of a pharmaceutical method etc. can be used. Specifically, for example, nonionic surfactants, anionic surfactants and the like can be mentioned. As the nonionic surfactant, for example, polyoxyethylene hydrogenated hydrogenated castor oil, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene behenyl ether, etc. Ethylene alkyl ether, polysorbate, decaglyceryl oleate and the like can be mentioned. Examples of the anionic surfactant include sodium polyacrylate and the like. These can be used alone or in combination of two or more depending on the kind of pigment to be contained in the aqueous ink composition.

  When triiron trioxide is used as a pigment, sodium alginate is suitable as a pigment dispersant. Sodium alginate is adsorbed to triiron tetraoxide and functions as a pigment dispersant, thereby imparting to the pigment electric repulsion by ionization (ionization) of sodium alginate and repulsion by steric hindrance. Since the triiron trioxide pigment has magnetism, the cohesion between particles is strong, but sodium alginate can prevent reaggregation of triiron trioxide pigments due to repulsion or the like. As a result, it is possible to provide a pigment dispersion excellent in dispersibility and dispersion stability.

  The sodium alginate is not particularly limited as long as it meets the criteria such as pharmaceutical additives specified by the Pharmaceutical Affairs Law, and it is possible to use a commercially available product. As such a commercial item, for example, Kimika Algin ULV-L3 (viscosity 20 mPa · s to 50 mPa · s at 10 mass% aqueous solution at 20 ° C.), Kimika Algin ULV-1 (10 mass% aqueous solution at 20 ° C viscosity 100 mPa · s) ~ 200 mPa · s, Kimika Algin ULV-3 (viscosity 300 mPa · s to 400 mPa · s at 10 ° C aqueous solution at 20 ° C), Kimika Algin (viscosity 1800 mPa · s to 2300 mPa · s at 10 ° C aqueous solution at 20 ° C), etc. (All are made by Kimika Co., Ltd.). These sodium alginates can be used alone or in combination of two or more, as needed.

  The weight 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 making the mass average molecular weight 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 trioxide from being reduced or being unable to be dispersed. In addition, the dispersion time can be shortened, and the average dispersed particle size of the iron trioxide can be prevented from becoming too large. Incidentally, by making the mass average molecular weight of sodium alginate 10,000 or more, the sodium alginate adsorbed on the surface of the pigment can sufficiently exhibit the repulsive force due to steric hindrance and the like, whereby the pigments reaggregate. It can be suppressed.

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

  The content ratio of sodium alginate to triiron ferric oxide is preferably 0.03 or more and 0.25 or less, more preferably 0.05 or more and 0.2 or less, and more preferably 0.08 or more and 0. It is particularly preferred that it is 15 or less. By setting the content ratio of sodium alginate to triiron ferric oxide to 0.03 or more, it is possible to suppress the decrease in the dispersibility of ferric iron trioxide too much. On the other hand, by controlling the content ratio of sodium alginate to iron trioxide to 0.25 or less, the viscosity is prevented from increasing excessively, and a shearing force or the like is applied to refine and disperse the aggregated pigment particles. The advancing time (dispersion time) up to the end can be shortened, and the average dispersed particle size of triiron trioxide can be suppressed from becoming too large.

  The content ratio of the pigment to the pigment dispersant is preferably 1: 0.03 to 1: 4, and more preferably 1: 0.5 to 1: 1 on a mass basis. The fall of the dispersibility of a pigment can be prevented as content ratio is 1: 0.03 or more. On the other hand, when the content ratio is 1: 4 or less, it is possible to prevent a decrease in the dischargeability due to the adhesion of the nozzle plate.

  In the aqueous ink composition of the present embodiment, a fading inhibitor may be contained. An antifading agent has the function of suppressing the penetration of the solid preparation against a dye having the property of permeating the solid preparation with the passage of time due to humidity (hereinafter referred to as "specific dye"). Have. Here, as a specific dye, for example, red No. 2, red No. 3, red No. 4, red No. 40, red No. 102, yellow No. 4, yellow No. 5, yellow No. 3, green No. 3, blue No. 1, blue No. 2, Copper chlorophyllin sodium etc. are mentioned. Moreover, when a specific dye and other dyes other than the said specific dye are contained, it can also suppress that these separate. As a result, the occurrence of discoloration and discoloration of the printed image can be reduced, and the visibility of the printed image can be maintained at a good level. The fading inhibitor also has a function of suppressing the photodecomposition of the specific dye upon irradiation with light such as natural light. Among the specific dyes, for example, azo dyes such as Red No. 2 and Red No. 40 and Red No. 102, and indigoid dyes such as Blue No. 2 are light-decomposed by light irradiation, and as a result, the printed image is light blue. May. However, since the antifading agent also suppresses the photodegradation of such a specific dye, the occurrence of photobleaching in the printed image can be reduced.

  The term "amber" means that the saturation of the printed image is irreversibly reduced as a result of the specific dye penetrating the solid preparation due to the humidity. In addition, “color change” means that, when a specific dye and another dye are contained, the specific dye and the other dye are separated as a result of the specific dye penetrating into the solid preparation due to humidity. The hue of the above is superior to that of a specific dye, which means that the hue and color tone of the entire printed image change irreversibly. "Light faded" means that the specific dye contained in the print image is photolyzed due to the influence of natural light etc., whereby the hue and color tone of the print image are irreversibly changed or the print image is deteriorated. .

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

  The monosaccharide is not particularly restricted but includes, for example, glucose, galactose, mannose and fructose. 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, palatinose (isomaltulose) and the like. Among 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, δ-cyclodextrin and the like.

  The sugar alcohols are not particularly limited, and examples thereof include mannitol, erythritol, reduced isomaltulose, xylitol, sorbitol and the like. Furthermore, reduced isomaltulose is a compound obtained by reducing isomaltulose by hydrogenation or the like. Reduced isomaltulose includes α-D-glucopyranosyl-1,1-mannitol (hereinafter referred to as “GPM”) and α-D-glucopyranosyl-1,6-sorbitol (hereinafter referred to as “GPS-6”). And a mixture of The mixing ratio of GPM and GPS-6 is not particularly limited, but generally, they are mixed in approximately equimolar amounts. Among sugar alcohols, reduced isomaltulose, xylitol and sorbitol are preferred in the present invention.

  Each of the fading inhibitors may 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, based on 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, it is 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 deposition of the fading inhibitor in the aqueous ink composition.

  In the aqueous ink composition of the present embodiment, water (water as a main solvent) is contained. As water, it is preferable to use pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, distilled water or the like, or from which ionic impurities such as ultrapure water have been removed. In particular, water sterilized by ultraviolet irradiation or hydrogen peroxide addition is preferable because it can prevent the generation of mold and bacteria over a long period of time. Moreover, it does not specifically limit as content of water, It can set suitably as needed.

  Further, in the aqueous ink composition of the present embodiment, other additives are blended if it meets the standard of the pharmaceutical additive, the Japanese Pharmacopoeia, or the official regulations of the food additive specified in the Pharmaceutical Affairs Law. It is also good. Additives include surface tension modifiers, wetting agents, water soluble resins, organic amines, surfactants, pH adjusters, chelating agents, preservatives, viscosity modifiers, antifoaming agents, dispersion stabilizers, reduction inhibitors And antioxidants. The content of these additives is not particularly limited except for the surface tension regulator and the wetting agent, and can be appropriately set as necessary (the content of the surface tension regulator and the wetting agent will be described later, respectively). ).

  The surface tension regulator is not particularly limited as long as it conforms to the standards of the Pharmaceutical Affairs Law, and specific examples thereof include glycerin fatty acid ester and the like. Examples of glycerin fatty acid esters include caprylic acid decaglyceryl, lauric acid hexaglycerin ester, oleic acid hexaglycerin ester, condensed linolenic acid tetraglycerin ester, fatty acid ester coconut palm, HLB decaglyceryl laurate, and HLB 13 Less than decaglyceryl oleate and the like. You may use these individually by 1 type or in mixture of 2 or more types.

  A commercial item can be used as a caprylic acid decaglyceryl, As such a commercial item, Ryoto (trademark) polyglyester CE19D (brand name, Mitsubishi Chemical Foods Co., Ltd. product, HLB value, for example) 15) SY Glyster MCA 750 (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) and the like.

In addition, the value of HLB is an HLB value by Griffin method, and means the value obtained by the following formula | equation.
HLB value = 20 × (sum of formula weight of hydrophilic group / molecular weight)
The HLB value is a value within 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 decaglyceryl laurate, one having an HLB of 15 or less can be used. If the HLB is greater than 15 and the deglyceryl laurate is generated, clogging of the nozzle of the inkjet head may cause fogging and the like, and the discharge stability may be degraded. The lower limit of HLB is preferably 10 or more from the viewpoint of solubility in a water solvent. Moreover, it is possible to use a commercial item as decaglyceryl laurate which has an HLB of 15 or less, and as such a commercial item, for example, NIKKOL (registered trademark) DECAGLYN 1-L (trade name, Nikko Chemicals ( HLB value 14.5), SY Glyster ML-750 (brand name, Sakamoto Yakuhin Kogyo Co., Ltd. product, HLB value 14.8) etc. are mentioned.

  As decaglyceryl oleate, one having an HLB of less than 13 can be used. If the HLB is 13 or more, the discharge stability may be deteriorated, for example, due to clogging of the nozzle of the ink jet head, such as occurrence of blur or the like. The lower limit of HLB is preferably 10 or more from the viewpoint of solubility in a water solvent. Moreover, as decaglyceryl oleate having a HLB of less than 13, commercially available products can be used. As such commercially available products, for example, NIKKOL (registered trademark) DECAGLYN 1-OV (trade name, Nikko Chemicals (trade name, Nikko Chemicals ( HLB value 12), SY Glyster MO-7S (brand name, Sakamoto Yakuhin Kogyo Co., Ltd. product, HLB value 12.9) etc. are mentioned.

  Commercial products can be used as the lauric acid hexaglycerin ester, and as such commercial products, for example, NIKKOL (registered trademark) HEXAGLYN 1-L (trade name, manufactured by Nikko Chemicals Co., Ltd., HLB value) 14.5), SY Glyster ML-500 (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 13.5), and the like.

  A commercial item can be used as oleic acid hexaglycerin ester, and as such a commercial item, for example, SY Glyster MO-5S (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 11.6) Etc.).

  Commercial products can be used as the condensed linolenic acid tetraglycerin ester, and examples of such commercial products include SY Glyster CR-310 (trade name, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), etc. .

  A commercially available product can be used as the fatty acid ester coconut palm, and as such a commercially available product, for example, Thirabazole W-01 (trade name, manufactured by Solar Chemical Co., Ltd.) and the like can be mentioned.

  The content of the surface tension regulator is preferably in the range of 0.1% by mass to 5% by mass, and more preferably in the range of 1% by mass to 2% by mass, with respect to the total mass of the aqueous ink composition. Is more preferred. When printing is performed by the inkjet method when the content of the surface tension adjusting agent is 0.1% by mass or more, discharge failure due to meniscus formation failure or the like in the nozzle of the ink jet head is prevented, and clogging of the nozzle Can be prevented. As a result, the ejection stability can be improved. On the other hand, when the content of the surface tension regulator is 5% by mass or less, it is possible to prevent the adverse effect on the discharge due to the insoluble portion of the surface tension regulator or the emulsification failure.

  The wetting agent is not particularly limited as long as it meets the standards of the Pharmaceutical Affairs Law, 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, and more preferably 10% by mass to 40% by mass, with respect to 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 discharge 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 meets the standard such as the Pharmaceutical Affairs Law, and specific examples thereof include disodium malate and the like. The addition amount of the dispersion stabilizer is not particularly limited, and can be appropriately set as needed.

  The aqueous ink composition of the present embodiment can be suitably used for an inkjet ink. Furthermore, the aqueous ink composition of the present embodiment is edible because it uses a material that meets the criteria of the pharmaceutical additive defined by the Pharmaceutical Affairs Act, the Japanese Pharmacopoeia or the official document of the food additive, Etc. can be printed directly on the surface of the tablet. In addition, non-contact printing by ink jet method is enabled even for tablets having poor surface smoothness such as uncoated tablets and OD tablets. Furthermore, since the aqueous ink composition of the present embodiment uses a pigment and a dye in combination, an image excellent in light resistance and color developability can be printed directly on the surface of a solid preparation such as a medicine or a supplement.

  The aqueous ink composition of the present embodiment is at least contained in an inkjet aqueous ink as a final product, and can also be used as the aqueous inkjet ink itself.

(Printing method of print image of solid preparation)
The method of printing a printed image in the solid preparation of the present embodiment includes a preparation step of preparing an inkjet aqueous ink (hereinafter sometimes referred to as "aqueous ink") containing the above-mentioned aqueous ink composition, and an aqueous ink. And at least a printing step of using the ink jet printing on a solid preparation. In the case of adding a discoloration inhibitor to the aqueous ink composition, a fading suppression step can be included after the printing step to suppress fading of the printed image.

  The preparation step of the aqueous ink may include a preparation step of the aqueous ink composition. The method for producing the aqueous ink composition is not particularly limited. For example, a method for producing a pigment composition by adding a dye or the like to the pigment composition may be mentioned.

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

  The dispersion time in the dispersion 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 commonly used disperser. Specifically, for example, a ball mill, a roll mill, a sand mill, a bead mill, a paint shaker, a nanomizer and the like can be mentioned.

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

  It does not specifically limit as a mixing method of each material, For example, materials can be sequentially added to the container provided with stirring apparatuses, such as a mechanical stirrer and a magnetic stirrer, and stirring and mixing can be performed. Moreover, it does not specifically limit as a filtration method, For example, centrifugal filtration, filter filtration, etc. are employable.

  In addition, as another method of producing an aqueous ink composition, after mixing a pigment, a dye, a pigment dispersant, a solvent (dispersion medium) and other additives to be added if necessary, the mixture is sufficiently stirred. The method of producing is also mentioned.

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

  Also, the printing step includes a drying step of drying the ink droplets attached to the surface of the solid preparation. The drying method is not particularly limited, and natural drying and the like can be performed in addition to hot air drying. Also, the drying conditions such as the drying time and the drying temperature are not particularly limited, and can be appropriately set according to the discharge amount of the ink droplet, the type of the aqueous ink composition, and the like.

  Furthermore, when the aqueous ink composition contains a fading inhibitor, the above-mentioned fading suppression step is performed after the printing step. The fading suppression step is a step in which the fading suppression agent contained in the printed image suppresses that the specific dye penetrates into the solid preparation due to the humidity.

For example, when the image-printed solid preparation is stored for 24 hours under an atmosphere of a temperature of 25 ° C. and a relative humidity of 60%, L ^* a ^* is evaluated based on the printed image immediately after printing ^. The range of Δa ^* ₁ in the b ^* color system is preferably -18 or more, preferably -10 to +10, and more preferably -5 to +5. By setting Δa ^* ₁ to −18 or more, it is possible to reduce the color change of the printed image and maintain good visibility. As a result, even when product information and the like are printed on the surface of a solid preparation, it is possible to prevent misidentification of the product information and to reduce the occurrence of dispensing errors and accidental ingestion. In addition, the printing image immediately after printing means the printing 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)
(Where a ^* ₀ represents the L ^* a ^* b ^* color system value of the printed image of the solid preparation immediately after the printing step, and a ^* ₁ represents an atmosphere of 25 ° C. and 60% relative humidity for 24 hours. L ^* a ^* b ^* color system values of printed image of solid preparation after storage
The L ^* a ^* b ^* color system is a color space recommended by the International Commission on Illumination (CIE) in 1976, and referred to as the CIE 1976 (L ^* a ^* b ^* ) color system. In Japanese Industrial Standard, it is defined in JIS Z 8730.

  In the present embodiment, a light fading suppression step may be included which suppresses the photodegradation of the specific dye. As described above, since the fading inhibitor also has a function of suppressing the photodegradation of a specific dye such as an azo dye or an indigoid dye, this can reduce the light fading of the printed image.

For example, when the printed image on the solid preparation surface is irradiated with visible light (wavelength range of 380 nm to 750 nm) with an integrated light quantity of 1.2 million lxhr, the evaluation of the light fading suppressing effect is based on the printed image immediately after printing. The range of ΔE ^* (ab) in the L ^* a ^* b ^* color system is 17 or less, preferably 0 to 10, more preferably 0 to 5 can be one of the evaluation criteria. By setting ΔE ^* (ab) to 17 or less, light fading of the printed image can be reduced, and good visibility can be maintained. As a result, even when product information and the like are printed on the surface of a solid preparation, it is possible to prevent misidentification of the product information and to reduce the occurrence of dispensing errors and accidental ingestion. In addition, the printed image immediately after printing means the printed image after drying like the above-mentioned.

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 respectively expressed as follows.
ΔL ^* ₂ = L ^* _2- L ^* ₀
(L ^* ₀ represents the lightness of the L ^* a ^* b ^* colorimetric system immediately after the printing process in the printed image of the solid preparation, and L ^* ₂ represents the visible light of the integrated light amount of 1.2 million lx · hr in the printed image of the solid preparation Represents the lightness of the L ^* a ^* b ^* color system after irradiation.)
Δa ^* ₂ = a ^* ₂ −a ^* ₀
(A ^* ₀ represents the value of L ^* a ^* b ^* colorimetric system immediately after the printing process in the printed image of the solid preparation, a ^* ₂ is the visible light of integrated light quantity 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.)
Δ b ^* 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 is the 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.)

(Solid preparation)
In the present specification, "solid preparation" is meant to include food preparations and pharmaceutical preparations, and as a solid preparation form, for example, OD tablets (orally disintegrating tablets), plain tablets, FC (film coated) tablets, sugar-coated tablets And tablets or capsules. Also, the solid preparation may be for pharmaceutical use or food use. Examples of tablets for food use include health foods such as tablets and supplements.

  On the surface of the solid preparation, using an aqueous ink containing an aqueous ink composition, a print image consisting of a dried film directly printed by an inkjet recording method is formed. The dry film is at least composed of the pigment and the dye contained in the aqueous ink composition.

  In the solid preparation of the present embodiment, since the printed image formed of the dried film is excellent in light resistance, it is possible to prevent, for example, the deterioration of the image of various information such as product information. In addition, since the printed image is also excellent in color development, it is possible to improve the identification of the user. As a result, the solid preparation of the present embodiment maintains good visibility over a long period of time, making it possible to prevent dispensing errors and accidental ingestion.

  In addition, although the fading inhibitor suppresses the penetration of the specific dye into the solid preparation due to the ambient humidity as described above, this effect is particularly effective when the solid preparation is a sugar-coated tablet or FC tablet. It is. An example of a sugar-coated tablet in which the antifading agent of the present invention is particularly effective in its effect is a sugar-coated layer comprising sucrose, maltitol and the like. The content of sucrose, maltitol or the like in the sugar coating layer is not particularly limited, and can be appropriately set as necessary. Moreover, as an FC tablet in which the fading inhibitor of the present invention is particularly easy to exhibit the effect, those in which the film coat is made of a cellulose-based polymer compound such as hydroxypropyl methylcellulose can be mentioned.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, contents, and the like described in the following examples do not limit the scope of the present invention to them unless otherwise specified. In addition, each material of the aqueous ink composition for ink jet recording conforms to the standard of pharmaceutical additives, Japanese Pharmacopoeia or Food Additives Official Standards stipulated by the Pharmaceutical Affairs Law.

Example 1
In this example, first, 0.6 g of sodium alginate (manufactured by Kimica Co., Ltd.) as a pigment dispersant and 23.4 g of ion-exchanged water are added to 6 g of triiron iron trioxide (manufactured by Toka Kasei Co., Ltd.) as a pigment. The mixture was mixed in a container, and the mixture in the container was dispersed by a disperser (paint shaker, manufactured by Asada Iron Works Co., Ltd.) to prepare a pigment dispersion (the compounding ratio of pigment, pigment dispersant and ion-exchanged water is 1: 1: 0.1: 3.9). Subsequently, 2 g of decaglyceryl monocaprylate (trade name: SY Glyster MCA 750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) as a surface tension regulator and 30 g of propylene glycol as a wetting agent were prepared in the prepared pigment dispersion. 37.7 g of ion-exchanged water was added to the resultant so that the total content of ion-exchanged water was 61.1 g, to prepare a pigment composition according to this example. 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 the pigment composition, and the solid of Blue No. 2 was dissolved without precipitation. As a result, an aqueous ink composition was prepared in which black iron oxide was dispersed and blue No. 2 was dissolved and present (see Table 1).
(Example 2)
In this example, 9.2 g of Blue No. 1 was added as a dye instead of Blue No. 2. The blend ratio of each composition other than them was changed as shown in Table 1, and an aqueous ink composition according to the present example was produced in the same manner as in Example 1 (see Table 1).

(Example 3)
In this example, the content of iron trioxide was changed to 1.2 g. Furthermore, 0.01 g of Blue No. 1 was added as a dye instead of Blue No. 2. The blend ratio of each composition other than them was changed as shown in Table 1, and an aqueous ink composition according to the present example was produced in the same manner as in Example 1 (see Table 1).

(Example 4)
In this example, the content of iron trioxide was changed to 0.6 g. Furthermore, in place of Blue No. 2, 0.005 g of Blue No. 1 was added as a dye. The blend ratio of each composition other than them was changed as shown in Table 1, and an aqueous ink composition according to the present example was produced in the same manner as in Example 1 (see Table 1).

(Comparative Examples 1 to 4)
In Comparative Examples 1 to 4, the blend ratio of each composition was changed as shown in Table 1, and no dye was added. Aqueous ink compositions according to Comparative Examples 1 to 4 were produced in the same manner as in Example 1 except for the above.

(Comparative example 5)
In this comparative example, the blend ratio of each composition was changed as shown in Table 1. Moreover, the addition amount of blue No. 2 which is a dye was changed to 0.6 g. An aqueous ink composition according to this comparative example was produced in the same manner as in Example 1 except for the above.

(Example 5)
In the present example, first, 8 g of red No. 40 aluminum lake (manufactured by San-Ei Gen Co., Ltd.) as a pigment, sodium polyacrylate as a pigment dispersant (trade name: TEGO (registered trademark) Dispers 715 W, manufactured by Evonik, Mass average molecular weight 3000) 6 g, disodium malate (made by Wako Pure Chemical Industries, Ltd.) 2 g as a dispersion stabilizer, and 44 g of ion-exchanged water are mixed in a container, and the mixture is dispersed (paint shaker, Asada Iron Works Co., Ltd. The resultant mixture was dispersed by a company to prepare a pigment dispersion (the blending ratio of pigment, pigment dispersant, dispersion stabilizer and ion-exchanged water is 1: 0.75: 0.25: 5.5). Subsequently, 30 g of propylene glycol as a wetting agent and 2 g of decaglyceryl monocaprylate as a surface tension regulator (trade name: SY Glyster MCA 750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) were added to the prepared pigment dispersion. Then, 6.9 g of ion-exchanged water was added so that the total content of ion-exchanged water was 50.9 g, to prepare a pigment composition according to this example.

  Further, 0.1 g of Blue No. 1 and 1 g of Yellow No. 4 were added to the pigment composition, and the solids of Blue No. 1 and Yellow No. 4 were dissolved without precipitation. As a result, an aqueous ink composition was prepared in which the red No. 40 aluminum lake was dispersed and the blue No. 1 and yellow No. 4 were dissolved (see Table 2).

(Comparative example 6)
In this comparative example, the blend ratio of each composition was changed as shown in Table 2, and no dye was added. An aqueous ink composition according to this comparative example was produced in the same manner as in Example 4 except for the above.

(Comparative example 7)
In the present comparative example, the blending ratio of each composition was changed as shown in Table 2. In addition, the addition amount of Blue No. 1 as a dye was changed to 1.2 g, and the addition amount of Yellow No. 4 to 12 g. An aqueous ink composition according to this comparative example was produced in the same manner as in Example 4 except for the above.

(Example 6)
In the present example, first, 8 g of yellow No. 4 aluminum lake as a pigment (manufactured by San-Ei Gen Co., Ltd.), sodium polyacrylate as a pigment dispersant (trade name: TEGO (registered trademark) Dispers 715 W, manufactured by Evonik, Mass average molecular weight 3000) 6 g, disodium malate (made by Wako Pure Chemical Industries, Ltd.) 2 g as a dispersion stabilizer, and 44 g of ion-exchanged water are mixed in a container, and the mixture is dispersed (paint shaker, Asada Iron Works Co., Ltd. The resultant mixture was dispersed by a company to prepare a pigment dispersion (the blending ratio of pigment, pigment dispersant, dispersion stabilizer and ion-exchanged water is 1: 0.75: 0.25: 5.5). Subsequently, 30 g of propylene glycol as a wetting agent and 2 g of decaglyceryl monocaprylate as a surface tension regulator (trade name: SY Glyster MCA 750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., HLB value 16) were added to the prepared pigment dispersion. In addition, 7.2 g of ion exchanged water was added so that the total content of ion exchanged water was 51.2 g, to prepare a pigment composition according to this example.

  Further, 0.5 g of Red No. 102 and 0.3 g of Blue No. 1 were added to the pigment composition, and the red No. 102 and Blue No. 1 solids were dissolved without precipitation. This produced an aqueous ink composition in which the yellow No. 4 aluminum lake was dispersed, and the red No. 102 and the blue No. 1 were dissolved and present (see Table 3).

(Comparative example 8)
In this comparative example, the blend ratio of each composition was changed as shown in Table 3, and no dye was added. An aqueous ink composition according to this comparative example was produced in the same manner as in Example 5 except for the above.

(Comparative example 9)
In the present comparative example, the blending ratio of each composition was changed as shown in Table 3. In addition, the addition amount of Red No. 102, which is a dye, was changed to 7 g, and the addition amount of Blue No. 1 to 4.2 g. An aqueous ink composition according to this comparative example was produced in the same manner as in Example 5 except for the above.

(Example 7)
In Example 7, the blend ratio of each composition was changed as shown in Table 4. Also, 1 g of reduced isomaltulose was added as a fading inhibitor. An aqueous ink composition according to this example was produced in the same manner as in Example 1 except for the above.

(Discharge stability)
Using an aqueous ink comprising the aqueous ink compositions of Examples 1 to 6 and Comparative Examples 1 to 9, printing was performed on one side of the plain tablet by an inkjet method to form an image on the plain tablet surface.

  Printing was performed by a single pass (one pass) method using an inkjet printer (KC 600 dpi head, medium speed printing jig). Also, printing was performed under the environment of a temperature of 25 ° C. and a relative humidity of 40%. Furthermore, after printing, hot air was directly applied by a dryer to sufficiently dry the printing surface.

  The evaluation of the ejection stability was carried out by stopping the ink jet printer after ejecting the water-based ink composition from the head and then observing whether or not nozzle looseness was observed in the printed image when printing again. The results are shown in Tables 1 to 3. In the table, ○ means that neither nozzle missing nor blurring was observed. The symbol “x” means that at least one of nozzle missing or blurring occurs during printing. The term “nozzle missing” means that ink droplets (droplets) of the aqueous ink composition are not ejected from the nozzle where clogging has occurred. Blurring means blurring of the image at the beginning of printing.

  As can be seen from Tables 1 to 3, it was confirmed that all of the aqueous ink compositions of Examples 1 to 6, Comparative Examples 1 to 3, Comparative Examples 6 and 8 exhibited good ejection stability. On the other hand, in Comparative Examples 4 and 5, when the content of the pigment is more than 10% by mass, the viscosity of the aqueous ink composition is increased, and the aqueous ink composition can not be ejected from the inkjet head. In the aqueous ink compositions of Comparative Examples 7 and 9, when the content of the dye is more than 10% by mass, solids of the dye are precipitated, and as a result, ejection failure from the ink jet nozzle occurs. From the above, as the aqueous ink composition for inkjet, the content of each of the pigment and the dye is 10% by mass or less, and the one dissolved to such an extent that the dye does not precipitate is from the viewpoint of discharge stability. It was confirmed that it was suitable as an aqueous ink for inkjet.

(Tone and hue)
The color tone and the hue were evaluated on the images printed on the surface of the uncoated tablet using the aqueous ink compositions of Examples 1 to 5 and Comparative Examples 1 to 3 and Comparative Examples 6 and 8. Evaluation criteria were as follows. In addition, in Comparative Examples 4, 5, 7 and 9, since the printing could not be performed due to the ejection failure, the color tone and the like of the printed image were not evaluated. The results are shown in Tables 1 to 3.
○: change in color tone and / or hue visually confirmed Δ: change in color tone and / or hue visually confirmed, but effect is smaller compared to ○ ×: color tone and hue It can not be judged visually that it has changed

  As can be seen from Table 1, in the aqueous ink compositions of Examples 1 to 3, comparison was made using only the black iron oxide pigment by adjusting the color tone and the hue by adding the blue No. 1 or blue 2 dye. Compared to Example 1, it could be improved to black without red. In particular, with the water-based ink compositions of Examples 1 and 2, the image could be printed with 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 4, comparison was made using only the lake pigment of the red No. 40 aluminum lake by adding Blue No. 1 and Yellow No. 4 to adjust the hue. Compared with Example 6, it was able to be adjusted to a good black, and the visibility of the printed image could be improved.

  Furthermore, as can be seen from Table 3, in the aqueous ink composition of Example 5, only the lake pigment of the yellow No. 4 aluminum lake as a colorant is added by adjusting the hue by adding the red No. 102 and the blue No. As compared to Comparative Example 8 used, it was possible to adjust to greenish black, and the visibility of the printed image could be improved.

(Evaluation of light fade resistance)
The fading resistance of the aqueous ink compositions of Examples 1 and 7 was evaluated by performing the following test under an environment of relative humidity 60%. That is, with respect to uncoated tablets (samples) after ink jet printing with the aqueous ink compositions according to Examples 1 and 7, L ^* a using a color difference meter (Model No .: VSS7700, manufactured by Nippon Denshoku Kogyo Co., Ltd.) ^* 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 an integrated light quantity of 0 lx · hr). The measurement was performed in two places in each of the printed images of Examples 1 and 7.

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

Note that ΔE ^* (ab) ₂ , ΔL ^* ₂ , Δa ^* ₂ , and Δb ^* ₂ shown in each table were calculated by the following general formulas.
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
Δ b ^* 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 is light faded. Was confirmed.

On the other hand, in the sample of Example 7, the increase in the color difference ΔE ^* (ab) ₂ of the printed image printed on the plain tablet could be significantly suppressed. Thereby, in Example 7, it was confirmed that the photodegradation of the indigoid dye of Blue No. 2 in the printed image can be reduced, and the reduction of light fading is possible. In addition, "pseudo-color" shown in Table 5 means that the color of the image printed on the uncoated tablet is shown by being substituted by another color.

Claims (8)

An aqueous ink composition for ink jet printing used for printing on a solid preparation, comprising:
At least one edible pigment and at least one edible dye,
The pigment is contained in a dispersed state in the aqueous ink composition for inkjet,
The dye is contained by being dissolved in the aqueous inkjet ink composition as long as the dye does not precipitate.
An inkjet aqueous ink composition, wherein the content of each of the pigment and the dye is 10% by mass or less based on the total mass of the inkjet aqueous ink composition.   The aqueous ink composition for ink jet according to claim 1, wherein the dye is a color tone adjusting agent and / or a color tone adjusting agent. The pigment is at least one selected from the group consisting of red ferric oxide, yellow ferric oxide, ferric trioxide, carbon black, and lake pigments,
Further, the lake pigment is preferably 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, Yellow No. 3, Green No. 3, Blue No. 1 and Blue No. 2. The aqueous ink composition for ink jet recording according to claim 1 or 2, wherein the selected at least one dye is laked.   The said dye 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, green No. 1, blue No. 1, blue No. 2, chlorophyllins pigment and natural pigment The aqueous ink composition for inkjet according to any one of claims 1 to 3, which is at least one selected from the group consisting of   The ink according to any one of claims 1 to 4, wherein the content of the pigment is 0.1% by mass or more based on the total mass of the aqueous ink composition for inkjet.   The content of the said dye is 0.01 mass% or more with respect to the total mass of the said aqueous ink composition for inkjets, The aqueous ink composition for inkjets in any one of Claims 1-5. Further, it comprises at least one fading inhibitor selected from the group consisting of monosaccharides, disaccharides, dextrins and sugar alcohols,
The inkjet aqueous ink composition according to any one of claims 1 to 6, wherein the content of the fading inhibitor is 50% by mass or less based on the total mass of the inkjet aqueous ink composition. A solid preparation having a dry film of an aqueous ink for ink jet on the surface,
The solid formulation, wherein the inkjet aqueous ink comprises the inkjet aqueous ink composition according to any one of claims 1 to 7.