JPH08239606A - Recording fluid - Google Patents

Abstract

PURPOSE: To obtain a yellow recording fluid which gives a recorded image with a high density, is excellent in light resistance, water resistance, and color tone of a recorded image, and has a good storage stability by compounding an aq. medium and a specific colorant. CONSTITUTION: This recording fluid contains 0.5-5wt.% colorant represented by formula 1 (wherein X is a group represented by formula II or III; Y1 and Y2 are each a group represented by formula IV or V; A, B, C, and D are each H, methyl, methoxy, or ethoxy; and l1 , l2 , and m are each 1-6), 5-30wt.% water- sol. org. solvent, and 65-85wt.% water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording liquid. Particularly, it relates to a recording liquid for inkjet recording.

[0002]

2. Description of the Related Art A so-called ink jet recording method has been put into practical use in which a recording liquid droplet containing a water-soluble dye such as a direct dye or an acid dye is ejected from a minute ejection orifice to perform recording. Regarding this recording liquid, PP such as electrophotographic paper is used.
Fast fixing to general-purpose office paper such as C (plain paper copier) paper and fan-hold paper (continuous paper for computers), and good print quality, that is, bleeding It is required to have a clear outline and to have excellent stability during storage as a recording liquid.
Therefore, the solvent that can be used is extremely 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 period of time.
Further, it is required that the density of the printed image is high and that the water resistance and the light resistance are excellent. Further, there are the following problems regarding the color tone. When a yellow dye is used, the visibility as a color is low because the human visual sensitivity is relatively low especially in the yellow field. If the maximum absorption wavelength of the dye is not increased to improve the visibility, the color tone becomes reddish, which is not preferable.

On the other hand, a clear green is important in a full-color image, and in order to obtain it, a highly visible and greenish yellow dye is required. However, it has heretofore been difficult to provide a yellow dye satisfying many of the above requirements at the same time. Therefore, various methods (for example, JP-A-55-152,766 and JP-A-57-2) are used.
3,665, JP-A-59-58,066, JP-A-5
9-174,664, JP-A-60-199,077.
No. 59-226,072, JP-A 60-21
5,082, JP-A-60-243,174, JP-A-62-156,180, JP-A-1-123,866.
Nos. 2,153,977, etc.) have been proposed, but they have not yet fully satisfied the market requirements.

Further, JP-A-4-233,975 describes that a yellow dye in which a monoazo dye is linked by a divalent organic group can be used for ink jet recording. However, the linking group is not important, and
Only a structure such as phenylenediamine is exemplified, and since such a linking group is structurally planar, the color development of the recorded image is poor and the color density is insufficient. Further, all of the exemplified linking groups are conjugated systems, and dyes having such groups are not preferable because the color tone tends to deepen and become reddish or dark.

[0006]

DISCLOSURE OF THE INVENTION The present invention has good print quality even when recorded on plain paper for ink jet recording, writing, etc., and has a high density of recorded images, light resistance and especially water resistance. It is an object of the present invention to provide a yellow recording liquid which has excellent properties and color tone of a recorded image and has good stability when stored for a long period of time. Further, the recording liquid of the present invention is suitable not only for recording on neutral paper, but also when recorded on acidic paper or alkaline paper, the density of the recorded image is high and the water resistance is excellent, and good performance is obtained. Is shown.

[0007]

The present inventor has achieved the present invention by confirming that the above object is achieved when a specific dye is used as a component of a recording liquid. That is, the gist of the present invention resides in a recording liquid containing an aqueous medium and at least one dye represented by the following general formula [I] in the form of a free acid.

[0008]

Embedded image

A, B, C, D, E and F each independently represent hydrogen, a methyl group, a methoxy group or an ethoxy group, and l ₁ , l ₂ and m each independently represent a number of 1 to 6. Represent. )

The present invention will be described in detail below. The dye used in the present invention has a free acid form represented by the general formula [I] in claim 1. Among the dyes represented by the general formula [I] in the form of free acid, the dyes used in the recording liquid of the present invention are preferably those represented by the following general formula [II].

[0011]

Embedded image

(In the formula, X and Y ₁ , A and B have the same meanings as defined in the above general formula [I].)

As the positions of the azo group and the ethylsulfonyl group which are substituted on the benzene ring, the meta position or the para position is preferable, and the para position is more preferable in practical use. That is, the structure represented by the following general formula [III] is particularly preferable.

[0014]

[Chemical 4]

(X, Y ₁ , Y ₂ , A, B, C and D have the same meanings as those in the above general formula [I].

In the above general formulas [I], [II] and [III], X is

Embedded image

Since they contain a large amount of amine, they have an affinity for the sulfonic acid group in the structure of the dye matrix, and it is considered that the water resistance is improved by the aggregation of the dyes. Also,
Since the structure of the linking group X is non-planar, the color developability is also good. The dye used in the present invention has the general formula [I]
The free acid form represented by may be used as it is, or may be used in the form of a salt. Further, a part of the acid groups in the dye structure may be in the form of a salt, and a dye in the form of a salt and a dye in the form of a free acid may be mixed. Examples of such salts include alkali metal salts such as Na, Li and K, alkyl groups,
Examples thereof include ammonium salts which may be substituted with a hydroxyalkyl group and organic amine salts. Examples of organic amines include lower alkylamines, hydroxy-substituted lower alkylamines, carboxy-substituted lower alkylamines, and polyamines having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. When the dye is in the form of these salts, the type of the salt is not limited to one type, and a plurality of types may be mixed.

Specific examples of the dye used in the present invention include:
The form of the free acid is, for example, the following No. Examples thereof include dyes having structures shown in 1 to 5.

[0019]

[Chemical 6]

[0020]

[Chemical 7]

[0021]

Embedded image

The above-mentioned dyes are, for example, "New Dye Chemistry" (published by Gihodo on December 21, 1973) [No. 39]
6 to 409]], a diazotization step and a coupling step can be carried out. The content of the dye in the recording liquid of the present invention is 0.5 with respect to the total amount of the recording liquid.
It is preferably about 5 to 5% by weight, particularly about 2 to 4% by weight.

In the present invention, the dyes may be used alone or as a mixture of plural kinds. That is, it may be used in combination with other color dyes for color matching or color mixing. As the solvent to be added to the recording liquid, water and water-soluble organic solvents such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (molecular weight 190-40
0), glycerin, N-methylpyrrolidone, N-ethylpyrrolidone, 1,3-dimethylimidazolidinone, thiodiethanol, dimethylsulfoxide, ethylene glycol monoallyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, sulfolane. ,Ethyl alcohol,
It preferably contains isopropanol or the like. These water-soluble organic solvents are usually used in an amount of 5 to 5 with respect to the total amount of the recording liquid.
Used in the range of 30% by weight. On the other hand, water is used in the range of 65 to 85% by weight with respect to the total amount of the recording liquid.

The recording liquid of the present invention contains 0.
1-10 wt% urea, preferably 0.5-5 wt% urea,
By adding a compound selected from thiourea, biuret, and semicarbazide, or by adding 0.001 to 5.0% by weight of a surfactant, the quick-drying property after printing and the printing quality can be further improved. it can. When the recording liquid of the present invention is used for inkjet recording,
It is preferable to adjust the pH to about 7 to 11 with an alkali or the like before use.

[0025]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. [Example] 10 parts by weight of diethylene glycol, 3 parts by weight of isopropyl alcohol, Water was added to 3 parts by weight of dye 1 and the pH was adjusted to 9 with aqueous ammonia to make the total amount 100 parts by weight. The composition was thoroughly mixed and dissolved, pressure-filtered with a Teflon filter having a pore size of 1 μm, and then deaerated with a vacuum pump and an ultrasonic cleaner to prepare a recording liquid.

An ink jet printer (trade name: MJ-700, manufactured by Epson) using the obtained recording liquid
Inkjet recording was carried out on an electrophotographic paper (product of Fuji Xerox Co., Ltd.) to obtain a high density yellow print. The results of various evaluations by the methods (a), (b) and (c) are shown below. (A) Light resistance of recorded image: The printed matter was irradiated with a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) for 100 hours, but the discoloration and fading after irradiation was small.

(B) Water resistance of recorded image: Water resistance test (1) Test method After the recorded matter was immersed in tap water for 5 minutes, 1. The bleeding of the printed matter was visually examined. 2. The optical density (OD) of the solid printed portion before and after the immersion was measured with a Macbeth densitometer (TR927).

(2) Test Results As a result of the above 1, image bleeding was slight. The change in the OD value before and after the immersion in the above 2 was represented by the OD residual rate by the following formula, and was 96%.

[0029]

[Formula 1] OD residual rate (%) = (OD value after immersion / OD value before immersion) × 100

(C) Storage stability of recording liquid: When the recording liquid was sealed in a Teflon container and stored at 5 ° C. and 60 ° C. for 1 month, the change was examined and no precipitation of insoluble matter was observed. .

[Example 2] 5 parts by weight of glycerin, 10 parts by weight of ethylene glycol, Water was added to 2.5 parts by weight of the dye of No. 2 and the pH was adjusted to 9 with ammonia water so that the total amount was 100 parts by weight. The composition was treated by the method described in Example 1 to prepare a recording liquid. . Printing was performed in the same manner as in Example 1 using this recording liquid, and as a result, a high density yellow recorded material was obtained. Further, various evaluations according to (a) to (c) of Example 1 were performed on the recorded matter. As a result, good results were obtained as in the case of Example 1. Also,
In the evaluation of (1) of (b), it was visually confirmed that image bleeding was slight as in Example 1, and in the evaluation of (2) of (b), the OD residual rate was 95. %
Met.

Example 3 10 parts by weight of diethylene glycol, 5 parts by weight of N-methylpyrrolidone, 3 parts by weight of isopropyl alcohol, the above-mentioned No. Water was added to 3 parts by weight of the dye of 3, and the pH was adjusted to 9 with aqueous ammonia to adjust the total amount to 100.
By weight, the composition was treated by the method described in Example 1 to prepare a recording liquid. Printing was performed in the same manner as in Example 1 using this recording liquid, and as a result, a high density yellow recorded material was obtained. Further, for this recorded matter, (a) to
Various evaluations according to (c) were performed. As a result, good results were obtained as in the case of Example 1. In addition, in the evaluation of (1) of (b), it was visually confirmed that image bleeding was slight, as in Example 1, and in the evaluation of (2) of (b), the OD residual rate. Was 97%.

[Examples 4 and 5] The No. 1 used in Example 1 was used. Instead of the dye of No. 1, 4, no.
A recording liquid was prepared and printing was carried out by the method of Example 1 except that the dyes of 5 were respectively used, and various evaluations according to (a) to (c) of Example 1 were performed on this recorded matter. However, for the evaluation of (b), only the visual evaluation of (1) was performed. As a result, as in Example 1, good results were obtained.

[0034]

INDUSTRIAL APPLICABILITY The recording liquid of the present invention is used for ink jet recording and writing instruments, and when recorded on plain paper, a yellow recorded matter can be obtained, and its printing density, light resistance, and water resistance. In addition to being excellent in storage stability as a recording liquid.

Claims (1)

[Claims] 1. A recording liquid comprising an aqueous medium and a dye in the form of a free acid represented by the following general formula [I]. Embedded image A, B, C, D, E and F each independently represent hydrogen, a methyl group, a methoxy group or an ethoxy group, and l ₁ ,
l ₂ and m each independently represent a number of 1 to 6. )