JP7664871B2 - Ink, method for producing printed tablets using the same, and tablet printing device - Google Patents

Description

Embodiments of the present invention relate to ink, a method for producing printed tablets using the ink, and a tablet printing device.

By printing identifying information such as letters or symbols on tablets, the tablets can be more easily identified, preventing dispensing errors by pharmacists and preventing users from accidentally ingesting the tablets.

One method for printing on tablets is inkjet printing. Inkjet printing allows printing to be done on tablets without contact, so it is suitable for printing on tablets that are likely to disintegrate, such as orally disintegrating tablets (OD tablets).

In such inkjet printing, ink containing a dye (dye ink) may be used. Compared to ink containing a pigment, dye ink tends to produce darker printed characters and improve the visibility of identification information. In addition, because pigment-containing ink is in a state where the pigment is dispersed in a solvent, it is difficult to eject ink from the nozzles of an inkjet head, which can cause ejection failures and result in poor printing. On the other hand, dye ink is dissolved in a solvent, so it is easy to ensure ejection from the nozzles of an inkjet head, and print failures can be reduced.

JP 2011-236279 A

The present invention aims to provide an ink suitable for printing on alkaline tablets, a method for producing printed tablets using the ink, and a tablet printing device.

An ink according to an embodiment of the present invention is an inkjet ink for printing identification information of a predetermined color on an alkaline tablet, and is characterized in that it contains water, ethanol, a water-soluble high-boiling point organic solvent, and a pigment that exhibits a color different from the predetermined color before printing on the alkaline tablet and changes to the predetermined color after printing on the alkaline tablet , the predetermined color being blue, the pigment including Food Green No. 3, the content of the pigment being 0.1 to 10 weight percent, and the content of Food Green No. 3 being 0.5 to 8.0 weight percent .

The tablet manufacturing method according to an embodiment of the present invention is characterized in that the ink according to the above embodiment is supplied to a print head that ejects ink from a nozzle, and identification information is printed on an alkaline tablet with the ink using the print head.

The tablet printing device according to an embodiment of the present invention has a transport device that transports alkaline tablets, and a print head that prints on the alkaline tablets transported by the transport device by ejecting ink from a nozzle, and the print head prints identification information by ejecting the ink according to the embodiment.

In inkjet printing, ink filled in the inkjet head is ejected from an opening in the nozzle at the tip of the inkjet head. If the ink dries and adheres inside or around the nozzle opening, causing the shape of the opening to change or become clogged, this results in ejection failure. Furthermore, if the ink is highly viscous, it cannot be ejected normally from the nozzle, resulting in ejection failure. Droplets of ink ejected from the nozzle of the inkjet head land on the surface of the tablet to be printed, and the printing dots (points) formed by these droplets are combined to print letters, symbols, etc. in a pointillist style. If there is an ejection failure at this time, the printing dots will not be formed in the pattern that will become the letters or symbols, and the print will look faded or will not look like the desired letters or symbols, resulting in printing failure.

Furthermore, if the ink that has landed on the surface of the tablet does not dry quickly, the ink may peel off during transportation after printing, or adhere to other tablets or the transportation device, causing contamination. Therefore, the inkjet ink used for tablet printing needs to have both the ability to be ejected from the nozzle and the ability to dry after printing.

Some tablets contain alkaline ingredients or are coated with alkaline ingredients, and so their surfaces (at least the areas to be printed on) are alkaline (hereafter simply referred to as "alkaline tablets"). It has been found that when alkaline tablets are printed on using dye ink, the printed characters, etc., can discolor or bleed over time, depending on the dye.

In particular, when alkaline tablets are printed with ink containing edible blue No. 1 (Brilliant Blue FCF), a commonly used blue dye, and stored in an environment with a temperature of 40 degrees and a humidity of 75%, the printed identification information turns light purple within 1-2 days and bleeds. In other words, the color changes to a different color from the color immediately after printing or the desired color (prescribed color), so if a corporate logo or illustration containing blue is printed, for example, the impression will change. In addition, when characters are printed, the resulting bleed makes the characters unclear and reduces the identification of the tablets.

In addition, for example, the purple ink was created by mixing Food Red No. 3, which is a commonly used red dye, and Food Blue No. 1, which is a commonly used blue dye, and printing this on alkaline tablets. However, just like the blue ink, when stored in an environment with a temperature of 40 degrees and a humidity of 75% RH, the printed identification information would turn red within 1-2 days, the two mixed dyes would separate, causing spots, or bleeding would occur.

For example, orange ink was created by mixing Food Red No. 3, which is a commonly used red dye, with Food Yellow No. 4, which is a commonly used yellow dye, and this was printed on alkaline tablets. However, just like the other colors mentioned above, when stored in an environment with a temperature of 40 degrees and a humidity of 75% RH, the printed identification information turned yellow within 1-2 days, the two mixed dyes separated, causing spots, and bleeding occurred.

The inventors of the present application therefore invented an ink that, by blending a dye that exhibits a color different from a predetermined color (the color of the predetermined printed identification information) into the ink, enables printing of the predetermined color when the ink is used to print on alkaline tablets. For example, Edible Green No. 3 is used as the dye for an ink whose predetermined color is blue (or a color with a bluish tint). Edible Green No. 3 is a dye that is generally used as a green coloring agent, for example, in food. However, the inventors of the present application noticed that Edible Green No. 3 exhibits a blue color under alkaline conditions, and by blending Edible Green No. 3, invented an ink that exhibits a blue color on alkaline tablets.

Furthermore, cochineal dye was applied to the alkaline tablets as an ink dye with a specific purple color. Cochineal dye is a dye that is generally used as a red (maroon) colorant in foods, for example. However, the inventors of the present application noticed that cochineal dye turns purple under alkaline conditions, and by incorporating cochineal dye, they invented an ink that turns purple on alkaline tablets.

Food Red No. 102 was also used as a pigment for the ink, which has a specific color of orange. Food Red No. 102 is a pigment that is generally used as a red coloring agent, for example in food. However, the inventors of the present application noticed that Food Red No. 102 turns orange under alkaline conditions, and by blending Food Red No. 102, they invented an ink that turns orange on alkaline tablets.

Note that "a dye that exhibits a color different from the specified color" does not only refer to the color of the dye when it is in powder form, but also includes the color of the dye when it is dissolved in water and other additives are added to complete the ink, which is different from the specified color.

[ink]
The ink according to this embodiment will be described. The ink according to this embodiment is an inkjet ink, and contains at least water, ethanol, and a water-soluble high-boiling organic solvent in addition to any one of the dyes, for example, Food Green No. 3, cochineal dye, and Food Red No. 102. In addition, an emulsifier, a flavoring agent, a preservative, and the like may be blended as necessary. It is preferable that all of these ink compositions are edible.

(Pigments)
The ink of this embodiment contains at least Food Green No. 3 (Fast Green FCF) as a pigment when the specified color is blue, contains at least cochineal pigment as a pigment when the specified color is purple, and contains at least Food Red No. 102 (New Coccine) as a pigment when the specified color is orange.

The content of the dye is preferably 0.1 to 10 weight percent of the total ink composition, and more preferably 0.5 to 8 weight percent. If the content of the dye is less than 0.1 weight percent, the printed color will be pale and visibility will be poor. If the content of the dye is more than 10 weight percent, the ink will not be ejected normally due to an increase in ink viscosity, resulting in poor printing. It has been confirmed that the dye content described above always produces the desired color, regardless of the pH value of the alkaline tablet that is the printing target.

(ethanol)
Ethanol is preferably fermented ethyl alcohol or sugar cane alcohol from natural brewing. The content of ethanol is preferably 5 to 60 weight percent, more preferably 10 to 40 weight percent, based on the total composition of the ink. If the content of ethanol is less than 5 weight percent, the ink dries poorly, for example, it takes more than 3 seconds to dry after printing, so the ink peels off during transportation after printing, or adheres to other tablets or transportation devices, causing stains. In addition, the surface tension of the ink increases, making the printed ink more likely to be repelled by the surface of the tablet. In other words, since the ink does not wet and spread on the surface of the tablet, it does not dry easily, and since the contact area with the tablet surface is small, the adhesion is small, and it peels off when rubbed, for example, even after 24 hours. If the content of ethanol is more than 60 weight percent, the ink dries and adheres to the inside or around the opening of the inkjet nozzle, blocking the opening, causing ejection failure and deviation in the flight direction of the ejected ink, resulting in poor printing.

(Water-soluble high boiling point organic solvent)
The water-soluble high-boiling organic solvent is used for the purpose of preventing the nozzles of the inkjet head from drying. As the water-soluble high-boiling organic solvent, for example, one or more of propylene glycol and glycerin can be selected. The content of the water-soluble high-boiling organic solvent is preferably 1 to 60 weight percent, more preferably 2 to 55 weight percent, based on the total ink composition. If the water-soluble high-boiling organic solvent is less than 1 weight percent, printing defects occur due to drying of the ink in the inkjet nozzle. On the other hand, if it is more than 60 weight percent, the ink viscosity increases, preventing normal ejection of the ink, resulting in printing defects.

(emulsifier)
The emulsifier may be selected from one or more water-soluble emulsifiers selected from, for example, lecithin, glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, and polyoxyethylene sorbitan fatty acid esters. The emulsifier is not necessarily required, but if it is used, the content of the emulsifier is preferably 0.01 to 5 weight percent, more preferably 0.1 to 2 weight percent, based on the total ink composition. If the content is less than 0.01 weight percent, the surface tension of the ink increases, and an appropriate meniscus state does not form at the nozzle opening, resulting in printing defects such as ink not being ejected from the nozzle or ink not landing at the specified position even if ejected. If the content is more than 5 weight percent, the ink thickens and precipitates form over time, causing nozzle clogging, again resulting in printing defects.

(Ink manufacturing)
Next, the present embodiment will be specifically described with reference to examples and comparative examples shown in Table 1. However, these examples are merely examples, and the present invention is not limited to these examples.

In Examples 1 to 5 and Comparative Examples 1 to 5, the compositions shown in Table 1 were prepared in the blending ratios shown in Table 1. The blending ratios shown in Table 1 are all expressed in weight percent. Examples 1 to 3 are inks containing Food Green No. 3 when the specified color is blue (a color with a bluish tint, including dark blue and blue-green, for example). Comparative Examples 1 to 3 are inks containing a pigment that is widely used as a blue dye. Example 4 is ink containing cochineal pigment when the specified color is purple. Comparative Example 4 is ink containing Food Blue No. 1 and Food Red No. 3. Example 5 is ink containing Food Red No. 102 when the specified color is orange. Comparative Example 5 is ink containing Food Red No. 3 and Food Yellow No. 4.

The preparation procedure is as follows. First, all ingredients except for the pigments shown in Table 1 were dissolved by stirring while heating to 50°C. After each ingredient was dissolved, the pigments shown in Table 1 were mixed and further stirred at 50°C for 1 hour. The mixture was then left to stand for 1 hour, cooled to room temperature, and filtered to prepare the ink.

The pigments to be mixed may be in powder form, or may be dissolved in water or other liquid to form a solution, or may be dispersed in a paste. Ultimately, it is important that the pigments are dissolved or mixed evenly.

(Ink evaluation)
The prepared inks of Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated for ejection properties from the nozzles using an inkjet head. Furthermore, characters were printed on the tablets to be printed, and the light resistance of the print and the stability over time of the print were evaluated (the methods for each evaluation are described below). In each evaluation, OD tablets, which are a type of alkaline tablet and contain magnesium oxide as a main component, were used as the printing subject. The results are shown in Table 1.

Comparative Example 3 was excluded from the measurements and evaluations because it was not possible to filter it.

<Evaluation of ejection from nozzle>
The ejection properties from the nozzles were evaluated by filling an ink jet head with ink, leaving it for 15 minutes, and then conducting a printing test to visually check for the presence or absence of printing defects.

Good: Each printing dot is formed in the specified position.

×: Missing print dots and/or each print dot is not landed in the specified position.

<Evaluation of light resistance of print>
The light resistance of the print was evaluated by exposing the printed tablets to light at 1000 lux for 50 days in an unpackaged state after printing, and visually checking whether the print had faded.

〇: No fading of the print was observed.

×: The print has faded.

<Evaluation of print stability over time>
The stability of the print over time was evaluated by storing the printed tablets in an environment of 40° C. and 75% RH for 2 weeks, and visually checking for bleeding of the letters and for any change in color compared to immediately after printing.

〇: No bleeding or discoloration.

×: The color has changed to a color different from the desired color and/or the printing has bled and become difficult to read.

(result)
As can be seen from the experimental results of Examples 1 to 5 shown in Table 1, the inks containing any of Food Green No. 3, cochineal color, and Food Red No. 102 as the coloring matter had good nozzle ejection properties. Furthermore, when used to print on alkaline tablets, the inks had excellent light resistance and stability over time. The results are explained in more detail below.

<Examples 1 to 3>
In printing on alkaline tablets, Example 1 is an ink that is colored blue, Example 2 is a blue-green, and Example 3 is a dark blue. Examples 1 and 3 are inks in which the amount of Food Green No. 3 is changed, and Example 2 contains Food Red No. 102 and Food Yellow No. 4 in addition to Food Green No. 3. When printing was performed using each ink of Examples 1 to 3, each printed dot was formed at a predetermined position on the surface of the tablet. In the light resistance evaluation, the printed characters on the printed tablets did not change color from the color immediately after printing. In the evaluation of stability over time, the printed characters could be read well without bleeding. Furthermore, there was no discoloration over time, and the blue color was maintained.

<Comparative Example 1>
Comparative Example 1 is an ink that exhibits a blue color immediately after printing on an alkaline tablet. The pigment contains gardenia blue pigment. Natural pigments such as gardenia blue pigment need to be blended in large amounts to obtain sufficient darkness for printing. In the ink of Comparative Example 1, a sufficient amount of gardenia blue pigment was blended to make the print visible, resulting in high ink viscosity and poor ejection from the nozzle. In addition, in the light resistance evaluation, the print faded and was almost completely lost. In the evaluation of stability over time, no bleeding or discoloration of the print was observed.

<Comparative Example 2>
Comparative Example 2 is an ink that, when printed on an alkaline tablet, is blue immediately after printing. It contains Food Blue No. 1 as a coloring matter. When a tablet was printed using the ink of Comparative Example 2, each printed dot was formed at a predetermined position on the surface of the tablet. In a light resistance evaluation, no fading occurred. However, in a time stability evaluation, the print turned light purple in about 1 to 2 days. Furthermore, the print bleeds, making it difficult to read.

<Comparative Example 3>
Comparative Example 3 contains Food Blue No. 2 as a colorant. Food Blue No. 2 is one of the dyes commonly used as a blue colorant. However, in Comparative Example 3, Food Blue No. 2 has poor solubility, and even when made into ink, it could not be filtered.

Example 4
In printing on alkaline tablets, Example 4 is an ink that turns purple. When printing was performed using the ink of Example 4, each printed dot was formed at a predetermined position on the surface of the tablet. In the light resistance evaluation, the printed characters on the printed tablets did not change color from the color immediately after printing. In the evaluation of stability over time, the printed characters were easily read without bleeding. Furthermore, there was no discoloration over time, and the purple color was maintained.

<Comparative Example 4>
Comparative Example 4 is an ink that is purple immediately after printing on alkaline tablets. The pigments include Food Blue No. 1 and Food Red No. 3. When tablets are printed with an ink containing a mixture of these two pigments, each printed dot is formed at a predetermined position on the surface of the tablet. In the light resistance evaluation, no fading occurred. However, in the evaluation of stability over time, the print gradually began to separate into two colors, and in some cases the print turned red or became mottled within 1 to 2 days.

Example 5
In printing on alkaline tablets, Example 5 is an ink that is colored orange. When printing was performed using the ink of Example 5, each printed dot was formed at a predetermined position on the surface of the tablet. In the light resistance evaluation, the printed characters on the printed tablets did not change color from the color immediately after printing. In the evaluation of stability over time, the printed characters were easily read without bleeding. Furthermore, there was no discoloration over time, and the orange color was maintained.

<Comparative Example 5>
Comparative Example 5 is an ink that shows orange color immediately after printing on alkaline tablets. The dyes include Food Red No. 3 and Food Yellow No. 4. When tablets were printed with ink containing a mixture of these two dyes, each printed dot was formed at a predetermined position on the surface of the tablet. In the light resistance evaluation, the print faded. Furthermore, in the stability evaluation over time, the print gradually began to separate into two colors, and in some cases the print turned yellow or became mottled within 1 to 2 days.

(summary)
From the above-mentioned results, when printing is performed by the inkjet method, ink containing any one of edible green No. 3, cochineal coloring, and edible red No. 102 can stabilize the ejection from the nozzle and suppress the occurrence of printing defects. In addition, by printing on an alkaline tablet using ink containing any one of edible green No. 3, cochineal coloring, and edible red No. 102, a predetermined color (blue or a color including bluish in the case of edible green No. 3, purple in the case of cochineal coloring, and orange in the case of edible red No. 102) can be made to appear on the alkaline tablet. In other words, ink containing any one of edible green No. 3, cochineal coloring, and edible red No. 102 can print identification information of a predetermined color on the alkaline tablet. Furthermore, this ink has high light resistance and stability over time, and can suppress discoloration of the printed identification information. In addition, bleeding of the print can also be suppressed. Therefore, even after printing and storing the tablet, the identification information can be easily recognized, and dispensing errors and accidental ingestion can be prevented.

[Tablet printing device]
A tablet printing device can be used to print the identification information on the tablets. The tablet printing device has a conveying device and an inkjet print head. The conveying device is, for example, a suction conveying device that conveys tablets while suctioning and holding them. The print head is disposed so as to face the conveying surface of the conveying device, and ejects ink from a nozzle toward the tablets passing under the print head to print the identification information on the tablets. By supplying ink containing the above-mentioned dye to the print head of this tablet printing device and printing on the alkaline tablets being conveyed, the identification information can be printed in a predetermined color on the alkaline tablets.

[Other embodiments]
In the above-described embodiment, the predetermined color is blue, purple, or orange, but it is not limited thereto and may be other colors. For example, when the predetermined color is purple, lac pigment can be used in addition to cochineal pigment. When the predetermined color is light orange, safflower yellow can be used. When the predetermined color is reddish brown, turmeric pigment can be used. Lac pigment is a pigment used as a red coloring agent for food, for example, and safflower yellow and turmeric pigment are pigments used as yellow coloring agents.

The ink of the above-mentioned embodiment can be further mixed with other dyes to obtain a desired color. The other dyes can be one or more selected from conventionally known synthetic food dyes and natural food dyes.

Examples of synthetic food dyes include tar-based dyes, natural dye derivatives, natural synthetic dyes, titanium dioxide, etc. Examples of tar-based dyes include Food Red No. 2, Food Red No. 3, Food Red No. 40, Food Red No. 102, Food Red No. 104, Food Red No. 105, Food Red No. 106, Food Yellow No. 4, Food Yellow No. 5, Food Blue No. 2, Food Red No. 2 Aluminum Lake, Food Red No. 3 Aluminum Lake, Food Red No. 40 Aluminum Lake, Food Yellow No. 4 Aluminum Lake, Food Yellow No. 5 Aluminum Lake, Food Blue No. 2 Aluminum Lake, etc. As explained in Comparative Example 3, Food Blue No. 2 has poor solubility, but can be used in small amounts. As explained in Comparative Example 4, Food Red No. 3 is used in combination with Food Blue No. 1 to prepare purple ink, but color separation is observed, but it can be used in combination with other dyes. Natural pigment derivatives include copper chlorophyll, sodium copper chlorophyllin, and potassium norbixin, while natural synthetic pigments include β-carotene and riboflavin.

Natural food dyes include, for example, plant charcoal pigments, anthocyanin pigments, carotenoid pigments, quinone pigments, flavonoid pigments, betaine pigments, monascus pigments, and other pigments derived from natural products. Anthocyanin pigments include red radish pigment, red cabbage pigment, red rice pigment, elderberry pigment, cowberry pigment, gooseberry pigment, cranberry pigment, salmonberry pigment, perilla pigment, sweet blueberry pigment, strawberry pigment, dark sweet cherry pigment, cherry pigment, hibiscus pigment, huckleberry pigment, grape juice pigment, grape skin pigment, blackcurrant pigment, blackberry pigment, blueberry pigment, plum pigment, white wortberry pigment, boysenberry pigment, mulberry pigment, purple sweet potato pigment, purple corn pigment, purple yam pigment, raspberry pigment, redcurrant pigment, loganberry pigment, and other anthocyanin pigments. Carotenoid pigments include annatto pigment, gardenia yellow, and other carotenoid pigments. Quinone pigments include cochineal pigment, lithospermum pigment, lac pigment, and other quinone pigments. Flavonoid pigments include safflower yellow, sorghum pigment, onion pigment, and other flavonoid pigments. Betaine pigments include beet red pigment. Monascus pigments include monascus pigment and monascus yellow pigment. Other pigments derived from natural products include turmeric pigment, clover pigment, gardenia red pigment, and spirulina blue pigment.

Additives such as flavorings, preservatives (bacteriostatic agents), defoamers, and surfactants may be added to the ink as needed. Of course, if the subject of printing is medicine or food, these should also be edible. In addition, when mixing the various components of the ink, pre-treatments such as heating can be performed.

To stir the ink when preparing it, a commonly used stirrer such as a magnetic stirrer or a propeller stirrer can be used.

The ink may also contain pigments, such as vegetable charcoal pigments, titanium dioxide, and aluminum lake. To prepare an ink containing a pigment, it is necessary to disperse the pigment. This dispersion process can be carried out using any commonly used dispersing machine, without any particular limitations. Specific examples include ball mills, roll mills, sand mills, and bead mills.

There are no particular limitations on the method for filtering the ink, and centrifugal filtering, filter filtering, etc. can be used.

The above-mentioned tablets can include tablets used for medicine, food, cleaning, industrial or aromatic purposes, as long as at least the portion to be printed is alkaline. In addition to the above-mentioned bare tablets (plain tablets) and film-coated tablets (film-coated tablets), the tablets can also include sugar-coated tablets, enteric-coated tablets, gelatin-coated tablets, multi-layer tablets, and dry-coated tablets, and various capsule tablets such as hard capsules and soft capsules. Furthermore, tablets can have various shapes such as disks, lenses, triangles, and ellipses. In addition, if the tablet to be printed is for medicine or food, it is preferable for the composition of the ink used to be edible, but if this is not the case, it may be of a non-edible composition.

Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This new embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

Claims (7)

An inkjet ink for printing identification information of a predetermined color on an alkaline tablet, comprising:
Water,
Ethanol,
A water-soluble high-boiling organic solvent;
a dye that exhibits a color different from the predetermined color before being printed on the alkaline tablet and changes to the predetermined color after being printed on the alkaline tablet;
Including,
the predetermined color is blue;
The colours include Food Green No. 3,
The ink is characterized in that the content of the colorant is 0.1 to 10 weight percent, and the content of Food Green No. 3 is 0.5 to 8.0 weight percent . 2. The ink according to claim 1 , wherein the ethanol content is from 5 to 60 percent by weight. 3. The ink according to claim 1 , wherein the water-soluble high-boiling point organic solvent is either propylene glycol or glycerin, or both. 4. The ink according to claim 1 , wherein the content of the water-soluble high-boiling point organic solvent is 1 to 60 weight percent. 5. The ink according to claim 1 , wherein the alkaline tablet is a tablet containing magnesium oxide as a main component. Supplying the ink according to any one of claims 1 to 5 to a print head which ejects ink from nozzles;
A method for producing printed tablets, comprising using the print head to print identification information on the alkaline tablet with the ink. A conveying device for conveying the alkaline tablets;
a print head that prints on the alkaline tablets transported by the transport device by ejecting ink from a nozzle;
having
6. A tablet printing device, comprising: a print head that prints identification information by ejecting the ink according to claim 1 .