JPH10158558A - Ink for ink jet printer and confirmation of moist heat treatment by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink for an ink jet printer of a continuous method, capable of clearly detecting color change of a coloring agent by a moist heat treatment because of requiring no content of a charge-imparting agent by using C.I. basic green 1 as a coloring agent. SOLUTION: This ink for an ink jet printer includes C.I. basic green 1 and does not include a charge-imparting agent. The formulating amount of the C.I. basic green 1 is preferably 2-4wt.% based on the whole weight of the ink in the point of satisfying both easiness of determination of the color change by a humid heat treatment and an electric conductivity. An amino resin, an alkyd resin, etc., are exemplified as a binder resin. The formulating amount of the binder resin is preferably 2-30wt.% based on the whole ink weight. Alcohols, ketones, etc., are exemplified as a solvent. The formulating amount of the solvent is usually 60-95wt.% based on the whole ink weight. The viscosity of the ink is preferably 2-10cps at 25 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous ink jet printer ink and a method for confirming wet heat treatment using the ink.

[0002]

2. Description of the Related Art In a continuous type ink jet printer, recording is performed by controlling the charging of ink droplets by continuously ejecting ink droplets. Therefore, a charge imparting agent is an essential component in the ink used. It is contained.

[0003] On the other hand, in the sterilization of foods and pharmaceuticals,
The method of moist heat treatment in an autoclave or the like is adopted, but in order to confirm whether or not the specified moist heat treatment has been performed, it is printed on food, pharmaceutical packaging containers, etc. with ink containing a special coloring agent. It has been practiced to confirm whether or not the wet heat treatment can be performed by utilizing the color change of the colorant when the wet heat treatment is performed.

[0004]

However, when printing is performed on a packaging container or the like to which the above-mentioned wet heat treatment is performed by a continuous type ink jet printer, there are the following problems in confirming the wet heat treatment.

That is, as described above, a continuous type ink for an ink jet printer contains a charge-imparting agent as an essential component, and since this charge-imparting agent is generally colored, the color of the colorant obtained by wet heat treatment is increased. There was a problem that it was difficult to determine the change.

In view of the above, one of the objects of the present invention is to provide a continuous type ink jet printer ink which does not contain a charge imparting agent and which can clearly determine the color change of a colorant due to wet heat treatment. To provide.

Another object of the present invention is to provide a method for confirming a wet heat treatment which can clearly determine a color change caused by the wet heat treatment of an image formed by a continuous type ink jet printer.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a continuous ink jet printer ink.
As a coloring agent, C.I. I. Contains Basic Green 1,
The present invention relates to an ink for an ink jet printer, which does not contain a charge imparting agent.

Further, the present invention provides a method of forming a printed image on an article by using a continuous ink jet printer using the ink for an ink jet printer, subjecting the article to a wet heat treatment, and then discoloring the printed image. It relates to a method for confirming heat treatment.

In the present invention, the term “moisture heat treatment” means a heat treatment in the presence of water or steam, particularly a heat treatment in the presence of pressurized steam. The moist heat treatment referred to in the present invention is mainly intended for sterilization and sterilization, but is not limited thereto. Typical examples of wet heat treatment include, for example, retort treatment of foods and the like, and autoclave treatment of foods and pharmaceuticals.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The ink for continuous ink jet printer of the present invention is C.I.
I. Basic Green 1 (CI Basic Gr)
een 1) and no charge imparting agent.

C. I. Basic Green 1 has a temperature of 1
Decomposes easily by wet heat treatment at 15 ° C. or more and changes from green to colorless.

In addition, C.I. I. Since Basic Green 1 has an action as a charge-imparting agent, a continuous ink jet printer ink containing this as a colorant does not contain a charge-imparting agent.
In addition to having good printing performance, it is possible to determine the color change of the obtained printed image due to wet heat treatment without being disturbed by the color of the charge imparting agent.

Therefore, when printing on the outer surface of a beverage can or the like with a continuous type ink jet printer using the ink for an ink jet printer of the present invention, a good quality image can be obtained and the image can be formed. When the moist heat treatment of 115 ° C. or more is performed on the beverage can, the imprint becomes colorless. Therefore, it can be confirmed that the predetermined moist heat treatment has been performed by changing the imprint to colorless.

Next, the present invention will be described in detail.

The ink for an ink jet printer of the present invention contains C.I. I. Except that it contains Basic Green 1 and does not contain a charge imparting agent, the composition of a conventional continuous-type ink jet printer ink can be employed without any particular limitation. I. It consists of Basic Green 1, a binder resin, a solvent and, if necessary, a wetting agent.

C. I. The amount of Basic Green 1 in the ink is preferably in a range where the color change due to wet heat treatment can be clearly discriminated. Is preferred.

In the ink of the present invention, a charge imparting agent is not separately used. I. The electric conductivity of the ink can be adjusted by changing the amount of the basic green 1. The electrical conductivity of the continuous ink jet printer ink is usually 0.7 to 1.2 mS / c.
m is preferable, and from this point, C.I. I. The amount of Basic Green 1 is 1.2 to 4 based on the total weight of the ink.
% Is preferable.

From the viewpoint of satisfying both the determination of the color change and the electric conductivity of the ink, C.I. I. The amount of Basic Green 1 is preferably in the range of 2 to 4% based on the total weight of the ink.

Examples of the binder resin include amino resin, alkyd resin, xylene resin, nitrocellulose, phenol resin, butyral resin, polyamide resin, rosin ester, rosin-modified phenol resin, and rosin-modified maleic resin. These may be used alone or as a mixture.

The amount of the binder resin is preferably from 3 to 30% based on the total weight of the ink. When the amount of the binder resin is less than the above range, the adhesive force of the ink to a printing material such as a beverage can becomes weak, while when the amount exceeds the above range, the viscosity of the ink becomes high, and the continuous method is used. Printing with an ink jet printer tends to be difficult.

Examples of the solvent include alcohols, alkylene glycol monoalkyl ethers, ketones and the like. Specifically, alcohols include methanol, ethanol, isopropanol, 1-butanol, 2-butanol and the like, and alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and the like, Ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. These may be used alone or as a mixture.

The amount of the solvent is not particularly limited as long as it can dissolve the dye and the binder resin and adjust the viscosity of the ink to an appropriate range.
A range of 95% is preferred.

Examples of the wetting agent used as required include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and propylene glycol monomethyl ether. These may be used alone or as a mixture.

The ink for an ink jet printer of the present invention can be prepared by adding a dye, a binder resin, and other additives to a solvent, dissolving the mixture by stirring and mixing, and, if necessary, filtering off insoluble components.

The ink of the present invention preferably has a viscosity in the range of 2 to 10 cps at 25 ° C. from the viewpoint of ink ejection performance.

In the method for confirming wet heat treatment according to the present invention, a print image is formed on an object to be subjected to wet heat treatment using a continuous ink jet printer using the ink, and the wet heat treatment is applied to the article on which the print image is formed. Is performed, and it is confirmed whether or not a predetermined wet heat treatment has been performed based on the color change of the printed image. If the normal image changes from green to colorless, it is determined that the wet heat treatment at 115 ° C. or higher for sterilization, usually about 120 ° C., has been properly performed.

Typical examples of the target articles include, but are not limited to, packaging bags and packaging cans for packaging foods, beverages, pharmaceuticals, and the like.

[0029]

Next, the present invention will be described with reference to experimental examples.

The ink composition of the formulation shown in Table 1 was sufficiently stirred and mixed, and the obtained mixture was suction-filtered with a glass fiber filter paper to remove insoluble matters, thereby preparing an ink for continuous ink jet printer. . The viscosity and electric conductivity of the obtained ink were measured. Table 1 shows the results.

Using the above ink, a continuous ink jet printer (IJ Printer GX-P manufactured by Hitachi, Ltd.) was used to form a printed image on the surface of an aluminum can for beverages. Next, the aluminum can having the image formed thereon was subjected to a wet heat treatment at 120 ° C. for 23 minutes in an autoclave.

The quality of the imprint formed on the surface of the aluminum can and the color change of the imprint by the wet heat treatment were determined according to the following criteria. Table 1 shows the results.

<Quality of Imprint> A clear image is formed. Δ: Dots are slightly seen. ×: No printed image is formed.

<Color Change Due to Moisture Heat Treatment> ・ ・ ・: Discrimination is easy. ×: Difficult to determine.

[0035]

[Table 1]

[0036]

The ink for an ink jet printer according to the present invention becomes colorless by a wet heat treatment as a colorant. I. Since it contains Basic Green 1 and does not contain a charge-imparting agent, the color change before and after wet heat treatment of an image formed on a printing material by a continuous ink-jet printer using the same is very clear, and a predetermined wet heat treatment is performed. It can be reliably determined whether or not is performed.

Claims (2)

[Claims] 1. An ink for continuous inkjet printer, wherein C.I. I. An ink for an ink jet printer comprising Basic Green 1 and no charge imparting agent. 2. An image is formed on an article by a continuous inkjet printer using the ink for an inkjet printer according to claim 1, and the article is subjected to wet heat treatment, and then the color of the image is changed. A method of confirming the wet heat treatment by the method.