JP3278476B2 - Recording ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for ink-jet recording and writing implements.

[0002]

2. Description of the Related Art Inkjet printers have advantages such as low noise, low running cost, and easy color recording, and have been rapidly spread in recent years as digital signal output devices. As such recording inks for ink jet printers, various materials have been proposed, such as inks mainly composed of water-based dyes, inks mainly composed of oil-based dyes, pigments, dispersed inks, and heat-meltable solid inks. . Among these, aqueous inks mainly based on aqueous dyes are the most suitable for society's demands for the maintenance of the global environment because of the high safety of the ink material to living bodies and the environment, and the low energy consumption of printers. It is considered to be. The performance required of such inks for ink jet printing mainly based on water-based dyes is as follows: 1) Non-coating such as copy paper, report paper, bond paper, foam paper, etc. which are generally used in offices and homes. Fast drying time and printing without bleeding on paper, so-called plain paper. 2) No bleeding at the pixel boundary in color color overlapping printing. 3) Excellent water resistance. 4) When filled in the head, there is no clogging of the head nozzle even after being left for a long time, and the reliability is high.

In order to satisfy these requirements, aqueous inks of various compositions have been conventionally proposed. For example, aqueous inks generally contain a water-soluble high-boiling organic solvent such as glycerol for the purpose of improving the reliability of the ink. However, when printing is performed on plain paper having a large size with such an ink, there is a problem that the ink penetrates slowly in the thickness direction of the paper and drying of a printing portion is poor. In this case, the image quality is significantly reduced.

[0004] In order to enhance the permeability of the ink in the thickness direction of the paper, for example, Japanese Patent Application Laid-Open No. 55-29546 proposes a method of adding a large amount of a surfactant to the ink.
In this case, there is a problem that bleeding occurs extremely depending on paper, and when ink is filled in the ink jet head, the ink is not discharged depending on the material and structure of the head.

In order to further improve the fixability and water resistance of the ink on paper, Japanese Patent Application Laid-Open No. 1-213376 discloses a technique for making the pH of the ink highly alkaline. In this case, there is a problem that, in addition to the safety for the living body, for example, the fixability and the water resistance of neutral paper are not sufficient.

Further, for the purpose of improving the bleeding of the ink, the drying property of the printed matter, and the clogging property of the head, for example, Japanese Patent Application Laid-Open No. 3-259967 proposes a technique in which an alkyl ether of polypropylene glycol is contained in the ink. Have been. In this case, the image quality of the color overlay printing of the color ink is not always satisfactory. As described above, various techniques have been proposed in addition to the above, but an ink which sufficiently satisfies the above requirements has not been known so far.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a drying time for uncoated paper commonly used in offices and homes, such as copy paper, report paper, bond paper and foam paper, so-called plain paper. An object of the present invention is to provide a recording ink capable of performing high-speed color printing without bleeding. It is another object of the present invention to provide a highly reliable ink with improved nozzle clogging when applied for ink jet recording.

[0008]

According to the present invention, there is provided a recording ink as set forth in the claims. That is, the recording ink of the present invention is characterized by containing a water-soluble dye, a water-soluble organic solvent and a compound represented by the following general formula (I).

[0009]

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(In the formula, R ₁ represents a linear or branched alkyl or alkenyl group having 8 to 22 carbon atoms.) Specific examples of the long-chain aliphatic trimethylol represented by the above general formula (I) include: , Trimethylol undecane, trimethylol tridecane, trimethylol pentadecane,
Trimethylol heptadecane, trimethylol nonadecane, trimethylol hen eicosane and the like can be mentioned. Among these, the following general formula

[0011]

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(Wherein, m and n each represent an integer of 0 to 19, and the sum of m and n is 7 to 19).

[0013] Trimethylol represented by the following formula is preferred.
Further, those in which the sum of m and n in the general formula (II) is 11 to 15 are preferable, and trimethylol isoheptadecane in which the sum of m and n is 13 is particularly preferable. Also, the branched methyl group is preferably located near the center of the alkyl main chain. The compound represented by the general formula (II) is exemplified below.

[0014]

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[0015]

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The compound represented by the above general formula (I) can be synthesized, for example, using the technique described in JP-A-3-66605. The blending amount of the long-chain aliphatic trimethylol in the recording ink of the present invention is not particularly limited,
Usually, it is in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight.

The long-chain aliphatic trimethylol used in the present invention has a hydrophilic portion composed of three hydroxyl groups in the molecule, and thus has excellent water retention and solubility of the dye, and as a result, an effect of preventing clogging is obtained. It is considered something. Further, because the balance between the hydrophilic portion is good that the a hydrophobic portion consisting of a long chain aliphatic group, with good paper permeability in the thickness direction of the ink on the paper is excellent in drying property, yet bleeding less printing
It is considered to give an image .

The water-soluble dye used in the recording ink of the present invention includes acid dyes such as azo, anthraquinone, indigo and phthalocyanine, basic dyes, direct dyes, reactive dyes and food dyes. .

Specific examples of applicable dyes include C.I.
I. Direct Black-17, -19, -22, -3
2, -51, -80, -91, -151, -154 and -168, C.I. I. Direct Blue 86 and -19
9, C.I. I. Direct Red-9 and -227, C.I.
I. Direct Yellow -86, -132 and -14
2, C.I. I. Acid Black-2, -24, -26,
-48, -52, -63, -172, -194 and -2
08, C.I. I. Acid Blue-9, -185 and -2
49, C.I. I. Acid Red-8, -35, -37,
-92, -94, -254 and -289, C.I. I. Acid Yellow-23 and -49, and C.I. I. Food black-2 and the like. The compounding amount of the water-soluble dye in the ink is 0.2 to 12% by weight, preferably 0.5 to 12% by weight.
It is in the range of 10% by weight.

The water-soluble organic solvent usable in the recording ink of the present invention includes ethanol, n-propanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,2-propanediol, dipropylene glycol. , Tripropylene glycol, 1,3-butanediol, 1,4-butanediol, glycerol, diglycerol, 1,2,4-butanetriol, 1,2,6
-Hexanetriol, ethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, thiodiethanol and the like.

The amount of the water-soluble organic solvent in the ink is preferably 1 to 50% by weight, more preferably 2 to 3% by weight.
The range is 0% by weight. The above water-soluble organic solvents can be used alone or as a mixture of two or more, but the most preferred solvent composition is at least one water-soluble high-boiling polyhydric alcohol such as diethylene glycol, triethylene glycol, glycerol, , 6-hexanetriol and the like. In addition to the ink of the present invention, various additives such as a pH adjuster,
A fungicide, a metal sequestering agent, a viscosity modifier and the like can be contained as necessary.

[0022]

EXAMPLES Next, examples of the present invention and comparative examples will be specifically described. In addition, all compounding amounts are weight%.

Embodiment 1 C.I. I. Direct Black 154 3.0% Exemplified Compound II-2 1.5% Diethylene glycol 7.5% Glycerol 2.5% Ethanol 3.0% Deionized water 82.5% (Production method) Water-soluble consisting of diethylene glycol, glycerol and ethanol Trimethylol isoheptadecane was added to the organic solvent, and the mixture was stirred and dissolved.The remaining components were added to the solution, and the mixture was thoroughly mixed and stirred. The resulting solution was filtered using a membrane filter having a pore diameter of 0.44 μm. After filtration under pressure, the ink of this example was prepared. Examples 2 to 11 According to the production method of Example 1, inks of the present Example having the compositions shown in Table 1 below were prepared.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

Comparative Examples 1 to 8 Inks of Comparative Example 1 having the compositions shown in Table 2 below were prepared in the same manner as in Example 1 except that trimethylol isoheptadecane was not used.

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

[Table 7]

* Surfynol 465: Nonionic acetylene glycol surfactant, Air Produ, USA
Next, print recording was performed on the inks of Examples and Comparative Examples of the present invention using a known inkjet printer (Desk Writer C manufactured by Hewlett-Packard Co., USA) to obtain (a) print quality and ( b) Drying time and (c) print quality in multicolor printing were evaluated.

(A) Printing Quality by Paper Type Recopying each dot printed on 6200 paper (high quality paper), Fuji Xerox R paper (recycled paper), and Gilbert Bond paper (bond paper), observes with a microscope, Were visually evaluated for feathering and sharpness of the outline, and no bleeding was observed. ほ と ん ど Little bleeding was observed.

(B) Drying time The solid portion printed on the recording paper is pressed against high quality paper,
The time during which the ink was not transferred was evaluated, and classified within 5 seconds 以内 5 to 15 seconds 15 to 30 seconds △ 30 seconds or more ×.

(C) Print Quality in Multi-Color Printing Multi-color printing was performed using cyan, magenta, and yellow inks on the above-described recording paper, and the ink bleeding in the color overlap portion and the sharpness of the printing were visually evaluated. No bleeding ◎ Almost no bleeding ○ Some bleeding △ Fair bleeding ×

Next, the noble clogging property of the ink was evaluated.

(D) Ink Nozzle Clogging A known ink jet printer (HG-3000, manufactured by Seiko Epson Corporation) is filled with the inks of the examples and comparative examples of the present invention, and is charged under an environment of 40 ° C. and 30% RH. Can be printed immediately after leaving it for one month without a nozzle cap. ○ Printable by circulating and cleaning ink. △ Not printable. The inks of Examples and Comparative Examples of the present invention were evaluated by the above evaluation methods. Table 3 shows the results of the evaluations (a), (b) and (d).

[0038]

[Table 8]

Table 4 shows the results based on the evaluation method (c). Table 4 shows the combinations of inks used in the printing evaluation.

[0040]

[Table 9]

As is evident from the evaluation results in Tables 3 and 4, the recording ink of the present invention exhibits excellent properties in monochrome and multicolor printing quality, drying time and clogging resistance.

[0042]

As described above, the recording ink of the present invention is used for ink-jet recording, writing implements, and the like.
Since it has excellent drying properties and print quality after recording, it is possible to obtain a high-quality color print image without bleeding on so-called plain paper such as copy paper, report paper, bond paper, and foam paper.

In particular, when used for multi-color ink jet recording, a high quality printed image having excellent color superposition can be obtained. Further, when the recording ink of the present invention is used for ink jet recording, reliability such as clogging resistance is extremely excellent in addition to the above characteristics.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-263165 (JP, A) JP-A-2-14260 (JP, A) JP-A-2-14262 (JP, A) JP-A-4- 211476 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-13/00

Claims (2)

(57) [Claims] 1. A recording ink comprising a water-soluble dye, a water-soluble organic solvent and a long-chain aliphatic trimethylol represented by the following general formula (I). Embedded image (Wherein, R ₁ represents a linear or branched alkyl or alkenyl group having 8 to 22 carbon atoms) 2. The recording ink according to claim 1, wherein the long-chain aliphatic trimethylol is represented by the following general formula (II). Embedded image (Wherein m and n each represent an integer of 0 to 19;
And the sum of n is 7-19).