JP7688532B2 - 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, it is possible to improve the identification of the tablets, prevent dispensing errors by pharmacists, and prevent 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 in a blue or bluish color on an alkaline tablet, the ink comprising a pigment including at least Food Blue No. 1, shellac, water, and ethanol , the pigment further comprising gardenia blue pigment, the pigment content being 0.1 to 10 weight percent, the shellac content being 0.5 to 10 weight percent, and the ethanol content being 5 to 60 weight percent .

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

The tablet printing device according to the embodiment of the present invention has a transport device that transports alkaline tablets, and a print head that prints by ejecting ink from a nozzle onto the alkaline tablets transported by the transport device, and the print head ejects the ink according to the embodiment described above.

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. In addition, 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.

Therefore, the inventors of the present application have invented an ink that can be used to print identification information on alkaline tablets even when Food Blue No. 1 is used as the dye.

[ink]
The ink according to this embodiment will be described. The ink according to this embodiment is an inkjet ink, and is a blue ink particularly suitable for printing on alkaline tablets. It contains at least Food Blue No. 1 as a coloring matter, and at least shellac as a resin. In addition, emulsifiers, flavorings, preservatives, etc. may be blended as necessary. In preparing the ink, it is preferable to use edible components, such as those approved by the Japanese Pharmacopoeia or the Official Specification of Food Additives, as each component.

(dye)
The ink of the present embodiment contains at least Food Blue No. 1 (Brilliant Blue FCF) as a colorant. It is more preferable that the ink contains Gardenia Blue colorant together with Food Blue No. 1.

The ink of this embodiment can also be mixed with other dyes in addition to the above-mentioned Food Blue No. 1 and Gardenia Blue dye to produce a desired color, such as blue or a blue-tinted color. As the other dyes, one or more types can be selected from conventionally known synthetic food dyes and natural food dyes. A color that contains a blue tinge is, for example, a color that contains blue as a color component, such as green or purple.

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 No. 5 Aluminum Lake, Food Blue No. 2 Aluminum Lake, etc. Natural dye derivatives include copper chlorophyll, copper chlorophyllin sodium, norbixin potassium, etc. Natural synthetic dyes include β-carotene, riboflavin, etc.

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, gardenia red pigment, and spirulina blue pigment.

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 is more than 10 weight percent, the ink will not be ejected normally due to the increased viscosity of the ink, resulting in poor printing.

(resin)
By blending a resin component into the ink, the adhesion of the ink to the tablet is improved, and the ink is printed on the tablet and then dried to form a film, so that abrasion resistance can be obtained. In the ink of this embodiment, shellac is used as the resin. Shellac is a resin obtained by refining a resinous substance secreted by lac scale insects, and is a mixture of multiple types of resin acid esters, waxes, pigments, etc. For blending into the ink, it is preferable to use white shellac, which is shellac that has been bleached, or refined shellac that has been treated to remove pigments and wax. In addition, by blending shellac into the ink, the viscosity of the ink can be increased, and the viscosity can be adjusted to an appropriate level for ejection from a nozzle using an inkjet head.

The shellac content is preferably 0.5 to 10 weight percent of the total ink composition, and more preferably 1 to 8 weight percent. If the shellac content is less than 0.5 weight percent, when printed on an alkaline tablet and stored in an environment with a temperature of 40 degrees and a humidity of 75% RH, the printed identification information will turn light purple within 1 to 2 days and bleed. If the shellac content is more than 10 weight percent, the ink will not be ejected normally due to an increase in ink viscosity, resulting in poor printing.

(pH adjuster)
Shellac is known to dissolve in alcohols as well as in alkaline aqueous solutions, and by making the ink alkaline, the shellac can be maintained in a dissolved state without precipitating. The pH adjuster is preferably one approved as a food additive. In order to obtain water resistance after printing of the ink containing shellac, it is preferable that the component be one that volatilizes when the ink dries, and for example, ammonium carbonate or ammonium hydrogen carbonate can be used. The pH of the ink is preferably 6.5 to 10.

(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.

For Examples 1 to 3 and Comparative Examples 1 and 2, the compositions shown in Table 1 were prepared in the blending ratios shown in Table 1. Note that all blending ratios shown in Table 1 are expressed in weight percent. Examples 1 to 3 are inks blended with Food Blue No. 1 and shellac. Comparative Example 1 is an ink blended with Food Blue No. 1 as a pigment (no shellac), and Comparative Example 2 is an ink blended with Gardenia Blue pigment as a pigment.

Comparative Example 1 does not contain shellac, so the proportion of propylene glycol is increased to adjust the viscosity to an appropriate level for printing with an inkjet head. Comparative Example 2 has a higher proportion of purified water and a lower proportion of ethanol compared to the other examples and comparative examples in order to dissolve the gardenia blue pigment.

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 sufficient that the pigments are dissolved or mixed uniformly.

(Ink evaluation)
The prepared inks of Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated for ejection 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.

<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.
A: Each printing dot is formed in the specified position.
×: Print dots are missing and/or each print dot does not land 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.
A: 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.
◯: No bleeding or discoloration.
Δ: Slight discoloration to a color different from the desired color and/or bleeding was observed to the extent that it did not affect the visibility of the print.
×: The color changed to a color different from the desired color and/or the print bled and became difficult to read.

(result)
As can be seen from the experimental results of Examples 1 to 3 shown in Table 1, the inks using Food Blue No. 1 as the colorant and containing shellac as the resin were excellent in light fastness and moisture fastness of the print when used to print on alkaline tablets. Furthermore, the inks containing Gardenia Blue colorant in addition to Food Blue No. 1 as the colorant were particularly good. The results will be explained in more detail below.

Example 1
The ink of Example 1 contains Food Blue No. 1 as a coloring matter and shellac as a resin. When the ink of Example 1 was filled into an inkjet head and printing was performed, each printed dot was formed at a predetermined position. In the light resistance evaluation, the print printed on the alkaline tablet had no change in color from immediately after printing. In the evaluation of stability over time, the blue color became slightly lighter and slight bleeding was observed, but it was not a problem for visibility.

Example 2
The ink of Example 2 contains gardenia blue pigment in addition to Food Blue No. 1 as a pigment, and shellac as a resin. When the ink of Example 2 was filled into an inkjet head and printing was performed, each printed dot was formed at a predetermined position. In the light resistance evaluation, the print printed on the alkaline tablet had no change in color from immediately after printing. In the evaluation of stability over time, no discoloration or bleeding over time was observed, and the print could be read well.

Example 3
The ink of Example 3, like Example 2, contains gardenia blue pigment in addition to Food Blue No. 1 as a pigment. When the ink of Example 3 was filled into an inkjet head and printing was performed, each printed dot was formed at the specified position. In the light resistance evaluation, the print printed on the alkaline tablet showed no change in color from immediately after printing. In the temporal stability evaluation, no discoloration or bleeding was observed over time, and the print was easily readable.

<Comparative Example 1>
The ink of Comparative Example 1 contains Food Blue No. 1 as a coloring matter, and does not contain a resin component. When the ink of Comparative Example 1 was filled into an inkjet head and printing was performed, each printed dot was formed at a predetermined position. In a light resistance evaluation, the print printed on the alkaline tablet did not change color from immediately after printing. However, in a time stability evaluation, the print changed color to light purple in about 1 to 2 days. Furthermore, the print bleeds, making it difficult to read the print.

<Comparative Example 2>
The ink of Comparative Example 2 contains gardenia blue pigment as a pigment, but does not contain a resin component. Gardenia pigment and other natural pigments must be blended in large amounts to obtain sufficient darkness for printing. In the ink of Comparative Example 1, a sufficient amount of gardenia pigment was blended to make the print visible, resulting in high ink viscosity and poor ejection from the nozzle. The composition shown in Comparative Example 2 also has a lighter blue color density than Example 1. 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.

(summary)
From the above results, when printing is performed by the inkjet method, the ink containing Food Blue No. 1 and shellac can stably eject the ink from the nozzle and suppress the occurrence of printing defects. Furthermore, this ink has high light resistance and stability over time, and can suppress discoloration of the printed identification information. It can also suppress bleeding of the print. Therefore, even after the tablets are stored after printing, the identification information can be easily recognized, and dispensing errors and accidental ingestion can be prevented.

Compared to inks that do not contain resin components, inks that contain shellac also have superior light resistance and stability over time. This is because the inclusion of shellac causes the printed ink to dry and form a film on the tablet, making the Food Blue No. 1 pigment less susceptible to the effects of decomposition by the alkali of the alkaline tablets. In addition, because shellac is an acidic resin, it is thought that it neutralizes with the alkaline tablets, minimizing the effect of alkali on the pigment. Food Blue No. 1 is a pigment that is widely used and has excellent color development, but it is unsuitable for use in printing on alkaline tablets due to its low stability over time. In contrast, the inclusion of shellac makes it possible to use Food Blue No. 1 for printing on alkaline tablets.

Conventionally, inkjet inks for printing on tablets that contain shellac often have a high ethanol content (for example, about 60 weight percent of the total ink composition). A high ethanol content can cause printing defects, as described above. By taking advantage of the fact that shellac dissolves in alkaline aqueous solutions and adjusting the ink solvent to alkaline using, for example, the pH adjuster described above, it is possible to prepare an ink in which shellac is dissolved, even if the ethanol content is reduced.

Furthermore, it is more preferable to incorporate gardenia blue pigment in addition to Food Blue No. 1 as a pigment. By incorporating both Food Blue No. 1 and gardenia blue pigment, the ink's stability over time can be further improved compared to when the pigment is Food Blue No. 1 alone. The results of Comparative Example 2 show that ink containing gardenia blue pigment has excellent stability over time. In other words, it appears that the ink's stability over time can be supplemented by incorporating gardenia blue pigment in addition to Food Blue No. 1.

[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 arranged 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. The print head of this tablet printing device is supplied with ink containing at least the above-mentioned edible blue No. 1 and shellac, and printing is performed on the alkaline tablets being conveyed, so that the identification information can be printed in blue or a color including a bluish color on the alkaline tablets.

[Other embodiments]
The ink may contain additives such as flavorings, preservatives (bacteriostatic agents), antifoaming agents, and surfactants, as necessary. Of course, when the printing subject is medicine or food, these may also be selected as edible materials. In addition, when mixing the components of the ink, pre-treatments such as heating or post-treatments may 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 an 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 embodied 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 (4)

An inkjet ink for printing identification information in blue or a color having a bluish hue on an alkaline tablet, comprising:
a colorant including at least Food Blue No. 1;
Shellac and
Water,
Ethanol,
Including,
The pigment further contains gardenia blue pigment,
The ink has a pigment content of 0.1 to 10 weight percent, a shellac content of 0.5 to 10 weight percent, and an ethanol content of 5 to 60 weight percent . 2. 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 claim 1 or 2 to a print head which ejects ink from nozzles;
A method for producing printed tablets, characterized in that the printing head is used to print identification information in blue or a color including bluish color on alkaline tablets using 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
The tablet printing device according to claim 1 or 2, wherein the print head prints the identification information in blue or a color including bluish by ejecting the ink according to claim 1 or 2.