JP3358349B2 - Recording liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording liquid. More specifically, the present invention relates to a black recording liquid suitable for inkjet recording.

[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 linear dye or an acid dye are ejected from a fine ejection orifice for recording. This recording liquid is used for general office work such as PPC (plain paper copier) paper such as electrophotographic paper and fan hold paper (continuous paper such as a computer), in addition to being capable of stable ejection for a long time. It is required that the fixation to the recording paper is fast and the print quality of the printed matter is good, that is, the print has no blur and the outline is clear, and the stability during storage as a recording liquid is also excellent. Therefore, 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 limited solvents as described above, and can stably discharge as recording liquids for a long time.
It is required to be stable even when stored for a long period of time, to have high density of printed image, and to be excellent in water resistance and light resistance. Was difficult.

For this reason, various methods (for example, Japanese Patent Application Laid-Open
No. 144067, JP-A-55-152747, JP-A-57-207660, JP-A-59-222602,
JP-A-61-2776, JP-A-61-57666,
JP-A-62-190269, JP-A-62-19027
No. 1, JP-A-62-190272, JP-A-62-19
7476, JP-A-62-250082, JP-A-62
JP-A-246975, JP-A-62-256974, JP-A-62-28859, JP-A-63-8463, JP-A-63-22867, and JP-A-63-117097
JP-A-63-30567, JP-A-63-3348
4, JP-A-63-63764, JP-A-63-105
No. 079, JP-A-64-31877, JP-A-1-93
No. 389, Japanese Patent Application Laid-Open No. 1-210464, Japanese Patent Application Laid-Open
0584, JP-A-2-16171, JP-A-2-14
No. 0270, JP-A-3-3-200882)
Have been proposed, but have not yet been able to fully satisfy the market requirements.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides good print quality even when recorded on plain paper for ink jet recording and writing instruments, etc., as well as high density of recorded images, light resistance, In particular, it is an object of the present invention to provide a black recording liquid having excellent water resistance and good stability when stored for a long time.

[0006]

Means for Solving the Problems The present inventors have confirmed that, when a dye having a specific structure is used as a recording liquid component, the performance particularly satisfying the above object can be obtained, and the present invention has been achieved. It is. That is, the gist of the present invention resides in a recording liquid in which the aqueous medium and the free acid form contain at least one kind of the dye represented by the general formula {1} in the above-mentioned claim 1. Hereinafter, the present invention will be described in detail.

The dye used in the recording liquid of the present invention has a free acid form represented by the general formula {1} in the first aspect. In the general formula {1}, R _{1 to} R ₄ each independently represent any one of a hydrogen atom, a hydroxyl group, and a sulfo group. m and n each represent an integer of 0, 1 or 2;
And n do not represent 0 at the same time. The anilino group is preferably substituted at the 6-position (that is, the J-acid derivative) and the 7-position (that is, the γ-acid derivative) of the naphthol group, and more preferably at the 7-position.

The dye used in the present invention may be used as it is in the form of the free acid represented by the general formula {1}.
When it is obtained in the form of a salt at the time of production, it may be used as it is, or it may be used after converting this salt form to a desired salt form. In addition, some of the acid groups in one molecule of the dye may be in the form of a salt, and the dye in the form of a salt and the dye in the form of a free acid may be used in combination. Examples of such salts include salt forms of alkali metals such as sodium, lithium and potassium, ammonium salts which may be substituted with an alkyl group or hydroxyalkyl group, and salts of organic amines. Examples of the organic amine include a lower alkylamine, a hydroxy-substituted lower alkylamine, a carboxy-substituted lower alkylamine, and a polyamine having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. In the case of the above salt form, the kind of the salt is not limited to one kind, and plural kinds may be mixed.

The salt is preferably an ammonium salt from the viewpoint of water resistance of the recorded image. Specific examples of these dyes include, for example, the following Nos. 1
And azo dyes having the structures shown in the following formulas (1) to (24). These dyes may be used alone or in combination depending on a desired color tone. It is also possible to use the dye of the general formula {1} in combination with a dye having another structure, preferably a dye having a yellow to orange structure, for example, C.I. I. It is preferable in terms of toning that Direct Yellow 86 is used in combination.

[0010]

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[0011]

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[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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The azo dye represented by the general formula {1} can be produced according to a method known per se. For example, the aforementioned No. The dye represented by No. 1 can be produced by the following steps (A) and (B). (A) Benzidine-3,3'-dicarboxylic acid and N-4 '
-Carboxyphenyl-γ-acid and tetrazotization and coupling steps according to a conventional method [for example, see Yutaka Hosoda, “Shin-Dye Chemistry” (published by Gihodo on December 21, 1973), pp. 396-409). A reaction solution containing the disazo compound is obtained.

(B) The reaction solution obtained in (A) is
By salting out with saline, the desired No. One dye is obtained. The content of the dye of the general formula {1} in the recording liquid is preferably 0.5 to 5% by weight, particularly preferably about 2 to 4% by weight based on the total amount of the recording liquid. A dye of the general formula {1} and a dye having a yellow to orange structure, for example, C.I. I. When Direct Yellow 86 is used in combination, the dye used in combination with the general formula {1} is used in an amount of 0.5 to 30% by weight, preferably 1 to 20% by weight.

The aqueous medium used in the recording liquid of the present invention includes water and water-soluble organic solvents such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, and the like.
Polyethylene glycol (molecular weight 200), polyethylene glycol (molecular weight 400), glycerin, N-methyl-pyrrolidone, N-ethyl-pyrrolidone, 1,3-dimethyl-imidazolidinone, thiodiethanol, dimethyl sulfoxide, ethylene glycol monoallyl ether, It preferably contains ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, sulfolane, ethyl alcohol, isopropanol, diethanolamine, triethanolamine and the like. These water-soluble organic solvents are usually used in an amount of 5 to 50% by weight, preferably 5 to 30% by weight, based on the total amount of the recording liquid.
Used in the range of weight percent. On the other hand, water is 45 to 95% by weight, preferably 65 to 85% by weight based on the total amount of the recording liquid.
Used in the range.

In the recording liquid of the present invention, 0.1% of the total amount of the recording liquid is used.
1 to 10% by weight, preferably 0.5 to 5% by weight of urea,
By adding a compound selected from thiourea, biuret, and semicarbazide, and by adding 0.001 to 5.0% by weight of a surfactant, it is possible to further improve the quick-drying property after printing and the print quality. it can.

[0022]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Example 1 10 parts by weight of diethylene glycol, 3 parts by weight of isopropyl alcohol, Water was added to 3 parts by weight of dye No. 1 and the pH was adjusted to 9 with aqueous ammonia to make the total amount 100 parts by weight. This composition was thoroughly mixed and dissolved, filtered under pressure through a Teflon filter having a pore size of 1 μm, and then deaerated by a vacuum pump and an ultrasonic cleaner to prepare a recording liquid.

Using the obtained recording liquid, ink jet recording was carried out on electrophotographic paper (Xerox Co., Ltd.) using an ink jet printer (trade name: HG-3000, manufactured by Epson) to obtain a high density (1.35). A black printed matter was obtained. The results of various evaluations by the following methods (a), (b) and (c) are shown. (A) Light fastness of a recorded image: A recording paper was irradiated with a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) for 100 hours. Discoloration after irradiation was small.

(B) Water resistance of recorded image: Water resistance test (1) Test method After immersing the recorded image in tap water for 5 minutes, bleeding of the image was visually inspected. The OD value (print density) of the solid printed portion before and after immersion was measured with a Macbeth densitometer (TR927). (2) Test Results As a result of the above, blurring of the image was slight. The change in the density of the solid printed portion before and after the above immersion was 99.8% when represented by the OD residual ratio according to the following equation.

[0025]

OD residual ratio (%) = (OD value after immersion / O before immersion)
D value) x 100

(C) Storage stability of the recording solution: When the recording solution was sealed in a Teflon container and stored at 5 ° C. and 60 ° C. for one month, no change of the insoluble matter was observed. Was. In the above evaluations (a), (b) and (c), the visual judgment was evaluated in three stages: ○: good, Δ: slightly poor, ×: bad.

Examples 2 to 4 The above Nos. Used in Example 1 were used. In place of the dye No. 1, 6, no. 13 and No. A recording liquid was prepared by the method of Example 1, and printing was performed using the recording liquid, except that each of the 18 dyes was used. Further, the recorded matter was subjected to (a) to (c) of Example 1. Various evaluations were made. As a result, good results were obtained in all cases as in Example 1. The OD residual ratio was 97.3%, 99.4%, 98.%, respectively.
2%. The results are shown in Table 1 below.

Comparative Example 1 C.1 dye instead of C.I. I. Using Food Black 2, a composition was prepared in the same manner as in Example 1 and then processed to obtain a recording liquid. Using this recording liquid, printing was performed in the same manner as in Example 1, and various evaluations of (a) to (c) of Example 1 were performed on the obtained recorded material. The results are shown in Table 1 below.

Comparative Example 2 A composition was prepared and treated in the same manner as in Example 1 except that the dye of the following structural formula * 1 was used instead of the dye of No. 1 to obtain a recording liquid. This dye did not dissolve in the ink composition up to 3% by weight, and the dye remained on the Teflon filter. Using this recording liquid, printing was performed in the same manner as in Example 1, and various evaluations of (a) to (c) of Example 1 were performed on the obtained recorded material. The results are shown in Table 1 below.

[0030]

[Table 1]

Examples 5 to 24 The above Nos. Used in Example 1 were used. In place of the dye No. 1, Nos. 2 to 5; Nos. 7 to 12; 14 ~
17, No. A recording solution was prepared and printed by the method of Example 1 except that each of the dyes of Nos. 19 to 24 was used and an aqueous solution of caustic soda was used instead of aqueous ammonia. Various evaluations according to (a) to (c) were performed. As a result, similar to Example 1, good results were obtained. In addition, the dye No. The OD residual ratio of the recording liquid using No. 2 was 99.2%. The recording liquid using No. 5 was 98.3%.

Embodiment 25 In the first embodiment, as shown in FIG. No. 1 instead of 3.0 parts by weight of the dye No. 1 2.5 parts by weight of the dye of C.1 and C.I. I. IRE
A recording liquid was prepared and evaluated in the same manner as in Example 1 except that 0.5 parts by weight of ct Yellow 86 was used. Although good results were obtained in the same manner as in Example 1, the color tone of the printed matter was medium black as compared with the bluish black of Example 1.

[0033]

The recording liquid of the present invention is used for ink-jet recording, for writing implements and the like. When recorded on plain paper, a black-based recording can be obtained, and its print density, light resistance and water resistance can be obtained. In addition to excellent storage stability, storage stability as a recording liquid is also good.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A recording liquid characterized in that the form of the aqueous medium and the free acid contains at least one dye selected from the dyes represented by the following general formula {1}. Embedded image (Wherein, R _{1 to} R ₄ each independently represent a hydrogen atom, a hydroxyl group, or a sulfo group, and m and n each represent the number of 0, 1 or 2. However, m and n are 0 at the same time. It will not be shown.) 2. The recording liquid according to claim 1, further comprising: C.I. I. A recording liquid containing Direct Yellow 86. 3. 45 to 95% by weight of water, 5 of a water-soluble organic solvent.
And at least one of the dyes represented by the general formula {1} according to claim 1 in an amount of 0.5 to 5% by weight of an ammonium salt.
The recording liquid according to claim 1, wherein the recording liquid is contained by weight. 4. A dye for a recording liquid having a free acid form represented by the following general formula {1}. Embedded image (Wherein, R _{1 to} R ₄ each independently represent a hydrogen atom, a hydroxyl group, or a sulfo group, and m and n each represent the number of 0, 1 or 2. However, m and n are 0 at the same time. It will not be shown.)