JP2002097393A - Ink set for ink jet recording and method for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set for ink jet recording giving an image having improved fastness of light cyan color part and mixed color part in the formation of a full color image and provide an ink jet recording method. SOLUTION: Two or more kinds of cyan inks having different color densities are used in the objective ink set for ink jet recording. The light colored ink having low color density contains at least one kind of C.I. Reactive Blue dye selected from C.I. Reactive Blue 7, 11, 14, 15, 15: 01, 18, 21, 23, 25, 35, 38, 41, 48, 63, 71, 72, 77, 80, 85, 92, 95, 105, 107, 118: 1, 123, 124, 136, 138, 140, 143, 148, 152, 153, 159, 174, 197, 207, 215, 227, 229 and 231.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink set for ink jet recording and a recording method. In particular, the present invention relates to an ink jet recording ink set and an ink jet recording method capable of improving the fastness of an image in a light-colored portion and a light-colored mixed portion when forming a full-color image.

[0002]

2. Description of the Related Art A so-called ink jet recording method has been put to practical use, in which droplets of a recording liquid containing a water-soluble dye such as a direct dye or an acidic dye are ejected from a fine ejection orifice to perform recording. Regarding the recording liquid used for this purpose, besides being capable of stable ejection for a long period of time, PPC (plain paper copier) paper such as electrophotographic paper, fan hold paper (such as continuous paper such as a computer, etc.) It is required that the fixation to the recording paper, which is widely used for paper, is fast and the print quality of the printed matter is good, that is, the print has no blur and the contour is clear.
Since it is necessary that the stability of the recording liquid during storage is also excellent, the solvent that can be used for the recording liquid is significantly limited.

On the other hand, dyes for recording liquids have sufficient solubility in the above-mentioned limited solvents and are stable even when stored as recording liquids for a long time.
In addition, it is required that the density of the printed image is high, and that it is excellent in water resistance and light resistance. However, it has been difficult to satisfy many of these requirements at the same time. in addition,
In recent years, inkjet recording has been required to be suitable for printing photo-like images, graphic images, and the like, which have greatly improved image quality compared to conventional inkjet recording.

[0004] When forming a full-color image, image robustness is particularly important among various required performances. Conventionally, as fastness of an image, discoloration and fading due to direct sunlight, so-called light fastness, have been regarded as a problem. For these discoloration and discoloration, a problem has been solved by using a dye having excellent light fastness, and C.I. I. Direct Blue 86 and C.I. I. Direct Blue 199 and the like have been used. However, recently, in addition to light resistance, discoloration and fading of an image in an indoor environment have been regarded as a problem. This discoloration proceeds even in a room that is not exposed to direct sunlight, and C.I. I. Direct Blue 86, C.I. I. Direct Blue 199 did not solve this problem.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an ink jet recording method, which comprises at least two dyes having different dye concentrations.
It is an object of the present invention to provide a recording method and an ink jet recording ink set that can form an image in which sharpness is improved and the lightness of a light-colored portion and a light-colored mixed portion is improved by using at least one kind of cyan ink. Is what you do.

[0006]

The present inventors have repeatedly studied an ink jet recording method using at least two or more kinds of cyan inks having different dye densities as the cyan ink. As a result, a specific dye among phthalocyanine dyes was used. It has been found that when used, the fastness of the light-colored portion can be significantly improved, and the present invention has been achieved.

That is, the gist of the present invention is that two dyes having different dye concentrations are used.
An ink set for inkjet recording using at least one kind of cyan ink, wherein a light-color ink having a low pigment concentration is selected from the group A below. I. An ink jet recording ink set and an ink jet recording method comprising at least one reactive blue dye. Group A: C. I. Reactive Blue 7, 11, 14, 1
5, 15:01, 18, 21, 23, 25, 35, 3
8, 41, 48, 63, 71, 72, 77, 80, 8
5, 92, 95, 105, 107, 118: 1, 12
3, 124, 136, 138, 140, 143, 14
8, 152, 153, 159, 174, 197, 20
7, 215, 227, 229, 231 Particularly, the dye contained in the light-colored ink is C.I. I. Reactive Blue 7, C.I. I. Reactive Blue 14,
C. I. Reactive Blue 15, C.I. I. Reactive Blue 21 and C.I. I. It has been found that the above problem can be solved by using at least one dye selected from the group consisting of Reactive Blue 63, and the present invention has been achieved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The ink used in the ink jet recording method of the present invention is an ink of three primary colors of yellow, magenta, and cyan, or four primary colors obtained by adding black to the three primary colors. Two or more kinds of color inks and a light color ink having a lower pigment concentration are used. The dark ink forms a high-density area when forming a full-color image, and the light-color ink forms a light-color area or a mixed-color area.

According to the present invention, there is provided an ink-jet recording ink set using two or more kinds of cyan inks having different dye concentrations, wherein the light-color ink having a low dye concentration is selected from the group consisting of the specific phthalocyanine dyes listed above. It is characterized by using a dye. Among them, the pigment contained in the light-colored ink is C.I. I. Reactive Blue 7, C.I.
I. Reactive Blue 14, C.I. I. Reactive Blue 15, C.I. I. Reactive Blue 21 and C.I.
I. It is preferable to use at least one dye selected from the group consisting of Reactive Blue 63. Most preferably, C.I. I. When Reactive Blue 14 is used, particularly excellent effects can be exhibited.

In the present invention, the specific C.I. I. If a reactive blue dye is used, the dye used as the dark color ink may use the above specific phthalocyanine dye similarly to the light color ink as long as a sufficient color density is obtained, or the phthalocyanine described above. Other than dyes may be used. However, in order to obtain a cyan image comparable to higher definition photographic quality, it is preferable to use a dye capable of achieving high density recording as the dark color ink, and use a dye other than the specific phthalocyanine dye used in the light color ink. It is preferably used.

In addition, C.I. I. Among reactive blue dyes, C.I.
I. More preferably, a reactive blue dye is used. Group B: C.I. I. Reactive Blue 7, 11, 14, 1
5, 21, 23, 35, 41, 63, 105, 118:
1, 124, 136, 138, 148, 197, 11
7, 231.

Among these, C.I. I. It is particularly desirable to use a dye selected from Reactive Blue 7, 14, 15, 21 and 63. Most preferably,
C. I. When Reactive Blue 14 is used, ink jet recording with particularly excellent robustness becomes possible.
Although the mechanism of this robustness is not clear, C.I.
I. Reactive Blues 7, 14 and 15 are dyes having a substituent having a triazine ring in the phthalocyanine skeleton of the copper phthalocyanine dye, and the substituent having the triazine ring is bulky. It is considered that the ink is protected, and particularly in the case of a light-colored ink, the fastness in the light-colored portion is considered to be significantly improved.

In Table 1 below, No. The dye of C.I. I.
Reactive Blue 7 (for example, Ciba Geigy, Ci
bacron Turquoise Blue G-
Known as E). No. 2 is C.I. I. Reactive Blue 15 (for example, Hi-Re manufactured by Hayashi Chemical Co., Ltd.)
act Turquoise Blue). C. I. Reactive Blue 14 is available in Color Index Third Edition, Volume 3, p. According to 3498, it is a phthalocyanine dye having a monochlorotriazinyl group.

[0014]

[Table 1]

In the cyan ink of the present invention, the above-mentioned group A: C.I. I. Reactive Blue 7, 11, 1
4, 15, 15: 01, 18, 21, 23, 25, 3,
5, 38, 41, 48, 63, 71, 72, 77, 8
0, 85, 92, 95, 105, 107, 118: 1,
123, 124, 136, 138, 140, 143, 1
48, 152, 153, 159, 174, 197, 20
The aqueous recording liquid may be prepared by using only a dye selected from the group consisting of 7, 215, 227, 229, and 231 or may be mixed with other general phthalocyanine dyes. Specific examples of such phthalocyanine dyes include C.I. I. Direct Blue 86 and C.I. I. Direct Blue 199 and the like.

In the present invention, C.I. I. A deep color ink having a high dye concentration containing at least one dye selected from Direct Blue 86 and 199; I. It is preferable in terms of color tone and fastness to use a combination of a light color ink having a low dye concentration and containing at least one dye selected from Reactive Blue 7, 14, 15, 21, and 63. In addition, as those used for the cyan dye of the dark ink, existing acid dyes, direct dyes, reactive dyes, food dyes, water-soluble dyes such as basic dyes, and the like, as a preferred example in terms of color tone, C. I. Acid Blue 9;

The dye used in the present invention may be converted to a desired salt form. A part of the acid groups may be of a salt type, and a salt type dye and a free acid type dye may be mixed. Examples of such salt forms include salts of alkali metals such as Na, Li, and K, salts of ammonium which may be substituted with an alkyl group or hydroxyalkyl group, and salts of organic amines. Examples of organic amines include lower alkylamines, hydroxy-substituted lower alkylamines,
Examples thereof include carboxy-substituted lower alkylamines and polyamines having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed. In the structure of the dye used in the present invention, when one molecule contains a plurality of acid groups, the plurality of acid groups may be of a salt type or an acid type and may be different from each other.

The dye concentration of the dark ink depends on the color value of the dye used, but is generally preferably about 2 to 5% by weight. The dye concentration of the light color ink depends on the color value of the dye used, but is preferably about 0.1 to 4% by weight. Inks containing these dyes are generally manufactured according to a method for manufacturing an ink used in an ink jet recording method.

The aqueous medium used in the ink includes water and water-soluble organic solvents such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (weight average molecular weight of about 190 to 400),
Glycerin, N-methylpyrrolidone, N-ethylpyrrolidone, 1,3-dimethylimidazolidinone, thiodiethanol, dimethylsulfoxide, ethylene glycol monoallyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-
It preferably contains pyrrolidone, sulfolane, ethyl alcohol, isopropanol and the like. These water-soluble organic solvents are usually used in the range of 1 to 50% by weight based on the total amount of the recording liquid. On the other hand, water is used in the range of 45 to 95% by weight based on the total amount of the recording liquid.

Further, the ink has a total amount of 0.1%.
By adding 10 to 10% by weight, preferably 0.5 to 5% by weight of a compound selected from urea, thiourea, biuret and semicarbazide, and 0.001 to 5% by weight of a surfactant, The quick drying property after printing and the print quality can be further improved.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist thereof. (Production Example 1) C.I. I. Reactive Blue 14 (manufactured by Ciba Geigy, Cibacron Blue P-4GN)
30 g was dissolved in 570 ml of water, 150 g of sodium chloride was added, the pH was adjusted to 1 with 35% hydrochloric acid, and the resulting solid was collected by filtration. To the obtained wet cake, 300 ml of water was added, and the mixture was dissolved at a pH of 6.0 with a 25% aqueous sodium hydroxide solution. 600 ml of isopropyl alcohol was added, and the resulting crystals were collected by filtration. The obtained wet cake was dried under vacuum at room temperature, and C.I. I. 13 g of a purified dye of Reactive Blue 14 was obtained. The maximum absorption wavelength of the obtained dye in water was 611 nm. (Example 1) (Preparation of ink) A dye was added to a solvent composed of diethylene glycol, diethylene glycol monobutyl ether and water, and the pH was adjusted to 9 with an aqueous sodium hydroxide solution to make the total amount 100 parts by weight. Dissolve,
After filtration under pressure with a Teflon (registered trademark) filter having a pore size of 1 μm, the ink was prepared by deaeration using a vacuum pump and an ultrasonic cleaner. Table 2 shows the composition of the ink, and Table 3 shows the dyes used and the amounts used. The cyan dye No. Is the above-mentioned No. 1 in Table 1. It corresponds to.

[0022]

[Table 2]

[0023]

[Table 3]

(Printing) Using the obtained cyan ink set, an ink jet printer (trade name: PM-750)
C, Seiko Epson Co., Ltd.), and a single solid cyan ink jet recording was performed on a special photo print paper (trade name: PMA4SP1, manufactured by Seiko Epson Corp.).
At this time, MS-Word (word processing software,
Microsoft Corporation), the printing density is the highest density solid printing, and 80% of the highest density solid printing, 60%
% And 40%, so that a total of four gradations were obtained to obtain a halftone cyan print. (Confirmation of saturation and fastness of image) Evaluation 1 Saturation of the highest density solid printing part was determined by Greta Macbeth SPM.
It was measured at 50. The saturation was 62.1. Evaluation 2 The recording paper was irradiated with a xenon fade meter (manufactured by Atlas Co., Ltd.) for 80 hours, and the degree of discoloration before and after that was measured with a Greta Macbeth SPM50 and quantified in the form of ΔE value. Here, the ΔE value is a numerical value indicating the degree of discoloration and fading. A larger value indicates a higher degree of discoloration and fading, that is, the light fastness of the image is low. For the evaluation, a 60% density printed portion, of which the fading behavior is conspicuous, was used.

As a result of the test, the light fastness of the ink set of the ink set of the present invention to ink-jet photo print paper was a good value of 3.8 as ΔE. Evaluation 3 The printed matter obtained by the above procedure was left in a room irradiated with a fluorescent lamp at 25 ° C. for 45 days. Differences were visually observed while comparing the obtained printed matter after the exposure test with the standard printed matter which was simultaneously printed and then sealed and stored in a cool and dark place, but the difference was hardly felt. (Example 2) Instead of the dye of Table-3 used in Example 1, printing was performed by the method of Example 1 using a cyan ink set prepared in the same manner as in Example 1 using the dye of Table-4. Was performed, and the chroma and fastness were evaluated.

[0026]

[Table 4]

The chroma in the evaluation 1 was 64.5. ΔE in Evaluation 2 was 5.0, which was a good result as in Example 1. In addition, the result of the visual judgment of Evaluation 3 was also good. (Example 3) In place of the dye of Table-3 used in Example 1, printing was performed by the method of Example 1 using a cyan ink set prepared in the same manner as in Example 1 using the dye of Table-5. Then, the chroma and the fastness were evaluated.

[0028]

[Table 5]

The chroma in the evaluation 1 was 67.0, which was a high chroma. ΔE in Evaluation 2 was 5.5, which was a good result as in Example 1. Further, the difference was slight in the visual observation of Evaluation 3. (Comparative Example 1) Using the cyan ink set prepared in the same manner as in Example 1 using the dyes in Table 6 instead of the dyes in Table 3 used in Example 1, printing was performed by the method in Example 1. Was performed, and the chroma and fastness were evaluated.

[0030]

[Table 6]

The chroma in the evaluation 1 was 67.0. ΔE in Evaluation 2 was 10.2, and discoloration was observed. In Evaluation 3, discoloration was clearly observed.

[0032]

According to the ink jet recording method of the present invention, a full-color image which is sharp and has improved lightness in a light-colored portion and a mixed portion of light-colored colors using at least two or more kinds of cyan inks having different dye concentrations. Can be recorded.

Claims (5)

[Claims] 1. An ink set for ink-jet recording using two or more types of cyan inks having different dye concentrations, wherein a light-colored ink having a low dye concentration is a C.I. I. An ink set for inkjet recording comprising at least one reactive blue dye. Group A: C. I. Reactive Blue 7, 11, 14, 1
5, 15:01, 18, 21, 23, 25, 35, 3
8, 41, 48, 63, 71, 72, 77, 80, 8
5, 92, 95, 105, 107, 118: 1, 12
3, 124, 136, 138, 140, 143, 14
8, 152, 153, 159, 174, 197, 20
7, 215, 227, 229, 231 2. The method according to claim 1, wherein the pigment contained in the light-color ink is C.I. I.
Reactive Blue 7, C.I. I. Reactive Blue 1
4, C.I. I. Reactive Blue 15, C.I. I. Reactive Blue 21 and C.I. I. Reactive Blue 63
2. The ink set for inkjet recording according to claim 1, wherein the ink set is at least one kind of dye selected from the group consisting of: 3. The ink set for ink jet recording according to claim 1, wherein the dye concentration in the light-color ink is 0.1 to 4% by weight. 4. A dark color ink having a high dye concentration is C.I. I. Direct Blue 86 and C.I. I. Direct blue 19
9 is a light-colored ink containing at least one dye selected from C.9 and having a low dye concentration. I. Reactive Blue 7, C.I. I. Reactive Blue 14, C.I. I. Reactive Blue 15, C.I. I. Reactive Blue 21 and C.I. I. The ink set for inkjet recording according to any one of claims 1 to 3, further comprising at least one dye selected from the group consisting of Reactive Blue 63. 5. An ink jet recording method using two or more kinds of cyan inks having different dye concentrations.
5. An ink jet recording method using the ink set for ink jet recording according to any one of items 1 to 4.