JPH06145572A - Water-base ink and method for recording therewith - Google Patents

Abstract

PURPOSE:To obtain a water-base ink which satisfies the requirements for an ink jet ink, is excellent in dryability, and gives an image resistant to quality degradation. CONSTITUTION:A water-base ink contains a water-dispersible or -sol. colorant, water, a wetting agent, and a compd. of the formula wherein M is an alkali metal ion, a quaternary ammonium, a quaternary phosphonium, or an alkanolamine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink composition suitable for ink jet recording, and more particularly to a water-based ink composition having excellent properties as a color ink for so-called plain paper.

[0002]

2. Description of the Related Art In recent years, ink jet printers have become popular due to their advantages of low noise and low running cost, and color printers capable of printing on plain paper have been put on the market. However, image color reproducibility, water resistance, light resistance,
It is difficult to satisfy all of the image dryness, image blurring, and ejection reliability. Particularly in the case of a color printer, even if the image quality is not deteriorated in the yellow, magenta, and cyan single-color printing portions, the image quality is easily deteriorated in the two-color overlapping portion of red, green, and blue. In particular, when drying is carried out without using a fixing device, as described in JP-A-55-29546, the permeability is increased to improve the drying property, so that the paper remarkably bleeds. Further, Japanese Patent Publication No. 60-23793 discloses that dialkylsulfosuccinic acid as a surfactant improves the drying property and causes little deterioration in image quality. On the side, there is a problem that the activator decomposes and loses its active effect during storage. In addition, Japanese Examined Japanese Patent Sho 58-
Japanese Patent No. 6752 discloses a quick-drying ink that causes less bleeding by improving the permeability of an ethylene oxide adduct having an acetylene bond by using a surfactant. However, depending on the dye, eg D
There is a problem that the drying speed is not improved due to hydrophobic interaction with the direct dye such as BK168.

Further, Japanese Patent Laid-Open No. 56-57862 discloses an ink containing a strongly basic substance.
The rosin-sized acidic paper works well, but it does not work on paper with alkyl ketene dimer or alkenyl sulfosuccinic acid as the sizing agent. Also, even with acidic paper, the effect of overlapping two colors is not effective.

Further, Japanese Patent Laid-Open No. 1-203483 discloses a recording liquid containing a polyhydric alcohol derivative and pectin, which contains pectin as a thickening agent to prevent bleeding. However, since pectin is a nonionic compound having a hydroxyl group as a hydrophilic group, there is a problem in that the ejection stability after the suspension of printing is lacking.

[0005]

SUMMARY OF THE INVENTION A first object of the present invention is to provide an aqueous ink recording composition which satisfies various characteristics as an ink jet ink, is excellent in drying property and has improved image quality deterioration. .

Another object of the present invention is to provide a recording method for favorably forming an image using the ink composition.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventor reduced the surface tension to 50 mJ / m ² or less by using a specific sulfonate as an ink component, and The present invention has been found out that the wettability can be improved, and image deterioration is extremely small as compared with the conventionally known surfactants.

That is, the present invention provides (1) an aqueous ink formula (I) containing a colorant, which is dispersed or dissolved in water, water and a wetting agent, and further containing a compound represented by the following structural formula.
And (2) A color image is formed on a recording material having a Steckigt sizing degree of 3 seconds or more by using the water-based ink containing the compound (I) described in 1 above and ejecting it from a fine ejection port to liquefy and fly. The gist is the recording method to be formed.

In addition to the above-mentioned characteristics, the water-based ink of the present invention has a substantially constant pixel diameter regardless of whether it is coated paper for inkjet, so-called plain paper. Further, it has the characteristic that the permeation rate is almost the same regardless of the dye. Since it has higher solubility in water than the conventionally known sodium dioctylsulfosuccinate, sodium di (2-ethylhexyl) sulfosuccinate and sodium dihexylsulfosulfosuccinate, it has excellent storage stability and discharge stability.

When a lithium ion and a quaternary ammonium or quaternary phosphonium represented by the following general formula are used as counter ions in the compound represented by the above formula (I) used in the present invention, storage stability at low temperature is obtained. It is possible to obtain an ink having higher reliability in terms of ink discharge stability and ejection stability.

[0011]

[Chemical 3]

(Y: nitrogen or phosphorus R _{3 to} R ₆ : hydrogen, alkyl group having 1 to 4 carbon atoms, hydroxyalkyl group, halogenated alkyl group) The pH of the ink of the present invention is 6 to 9. Is preferred. Within this range, the ink has excellent storage stability,
Stable discharge is possible even after long-term printing is stopped or during continuous jetting. If the pH exceeds 9, it tends to occur due to changes in physical properties due to decomposition of the active agent during storage. Most of copy papers and papers used in offices have a pH of 5 to 6, but ink is ejected onto these recording papers from a fine ejection port of 30 to 60 μm to form droplets having a weight of 30 to 160 ng. 6 to 2
It is possible to provide a recording method for forming a high-quality and high-resolution recorded image by flying at 0 m / s and performing so-called ordinary recording with a Steckigt sizing degree of 3 seconds or more.

Compound (I) that can be used in the present invention
It is possible to give a desired penetrability to the ink characteristics required by the printer system in an amount of 0.05 to 10% by weight. Here, if it is less than 0.05%, bleeding occurs at the boundary of the two-color overlapping portion in any case,
If it is added in an amount of more than 10% by weight, the compound (I) itself tends to precipitate at a low temperature, and the precipitation of a dye may occur, resulting in poor reliability.

Further, since the compound (I) is a sticky solid, it is preferably used as a mixture with an aliphatic alcohol to give fluidity. In this case, an ink can be easily produced and an ink composition having excellent permeability can be provided. The content of the aliphatic alcohol may be 0.1% to 5% by weight in the ink as long as the solubility of the dye is not hindered. Examples of aliphatic alcohols include ethanol, 2-propanol, propanol, butanol and the like.

To adjust the pH of the above-mentioned aqueous ink of the present invention, the compound (I) is added in the form of a free acid, and then sodium hydroxide, lithium hydroxide, or a counterion represented by the following formula is hydroxylated. It is preferable to add a substance.

[0016]

[Chemical 4]

(Y: nitrogen or phosphorus R _{3 to} R ₆ : alkyl group having 1 to 4 carbon atoms, hydroxyalkyl group, halogenated alkyl group) For example, in the case of a lithium salt, it can be carried out by adding lithium hydroxide. Regarding the quaternary ammonium, phosphonium, alkanolamine cations of formula (II),
Specifically, it is carried out by adding the hydroxide shown below.

[0018]

[Chemical 5]

(II-9) Triethanolamine cation (C ₂ H ₅ OH) ₃ NH + In the present invention, all counterions of the compound (I) are sodium, lithium and / or the above general compounds. It need not be a compound of formula (II) but can be mixed with other alkali ions. The amount of ions of sodium, lithium and / or the compound of the general formula (II) is preferably 30% or more, more preferably 50% or more with respect to the number of moles of the compound (I). The ink of the present invention uses water as a liquid medium. To make the ink have desired physical properties, to prevent the ink from drying, and to improve the dissolution stability of the compound of the present invention. The following water-soluble organic solvents can be used for the purpose of preventing the following water-soluble drying and for improving the dissolution stability of the compound of the present invention.

Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6 hexanediol, glycerol, 1,
Polyhydric alcohols such as 2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol Polyhydric alcohol alkyl ethers such as monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; N- Methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-capro Nitrogen-containing heterocyclic compounds such as cutam and γ-butyrolactone; amides such as formamide, N-methylformamide, formamide, N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine, etc. , Amines, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate and the like. These solvents are water alone, or a plurality of mixed propylene carbonate, ethylene carbonate and the like. These solvents may be used alone or in combination with water.

Of these, particularly preferred are diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4.
-Butanetriol, petriol, 1,5-pentanediol, and N-methyl-2-pyrrolidone, and by using these, excellent solubility for the present compound and excellent effect for preventing defective injection characteristics due to water evaporation Is obtained.

In addition to the compound (I) of the present invention, penetrants added for the purpose of adjusting the surface tension include diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, Alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monobutyl ether, propylene glycol monobutyl ether and tetraethylene glycol chlorophenyl ether, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol are mentioned, but particularly preferable. Is diethylene glycol monobutyl ether.

The surface tension referred to in the specification of the present invention is an index showing the penetrability into paper, and in particular, it shows the dynamic surface tension in a short time of 1 second or less after the surface is formed, and the static tension measured at the saturation time. Different from surface tension. As a measuring method, JP-A-63-3
Although any method can be used as long as it can measure the dynamic surface tension of 1 second or less by the conventionally known method described in Japanese Patent No. 1237, etc., in the present invention, it was measured using a Wilhelmy type hanging plate type surface tension meter. Surface tension value is 50mJ / m
^It is preferably ² or less, more preferably 40 mJ / m ² or less to obtain excellent dryness.

As the water-soluble dye used as the coloring material, those which are classified into acid dyes, direct dyes, basic dyes, reactive dyes and food dyes in the color index and which have excellent water resistance and light resistance are used. To be

Specific examples of these dyes include acid dyes and food dyes such as C.I. I. Acid. Yellow 17,23,42,4
4,79,142 C.I. I. Acid. Red 1,8,13,14,1
8, 26, 27, 35, 37, 42, 52, 82, 8
7, 89, 9297, 106, 111, 114, 115, 134, 18
6,249,254,289 C.I. I. Acid. Blue 9, 29, 45, 92, 2
49 C.I. I. Acid. Black 1, 2, 7, 24, 2
6,94 C.I. I. hood. Yellow 3,4 C.I. I. hood. Red 7, 9, 14 C.I. I. hood. As the black 1,2 direct dye, C.I. I. direct. Yellow 1,12,24,2
6,33,44,50 120,132,142,144,86 C.I. I. direct. Red 1,4,9,13,1
7, 20, 28, 31, 39, 80, 81, 83, 8
9,225,227 C.I. I. direct. Orange 26,29,62,1
02 C. I. direct. Blue 1, 2, 6, 15, 2
2,25,71,76,79,86,87,90,9
8, 163, 165, 199, 202 C.I. I. direct. Black 19, 22, 32, 3
8,51,56,71 74,75,77,154,168,171 As a basic dye, C.I. I. basic. Yellow 1, 2, 11, 13,
14,15,19,21,23,24,25,28,2
9, 32, 36, 40, 41, 45, 49, 51, 5
3,63,465,67,70,73,77,87,9
1, C.I. I. basic. Red 2, 12, 13, 14,
15, 18, 22, 23, 24, 27, 29, 35, 3
6,38,39,46,49,51,52,54,5
9,68,69,70,73,78,82,102,1
04, 109, 112 C.I. I. basic. Blue 1,3,5,7,9,2
1, 22, 26, 35, 41, 45, 47, 54, 6
2,65,66,67,69,75,77,78,8
9, 92, 93, 105, 117, 120, 122, 1
24, 129, 137, 141, 147, 155 C.I. I. basic. Black 2,8 As a reactive dye, C.I. I. Reactive. Black 3, 4, 7, 11,
12, 17 C.I. I. Reactive. Yellow 1,5,11,1
3,14,20,21,22,25,40,47,5
1,55,65,67 C.I. I. Reactive. Red 1,14,17,2
5,26,32,37,44,46,55,60,6
6,74,79,96,97 C.I. I. Reactive. Blue 1, 2, 7, 14, 1
5,23,32,35,38,41,63,80,95 etc. can be used. Particularly, acid dyes and direct dyes can be preferably used. Examples of the pigment include organic pigments such as azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, rhodamine B lake pigment, carbon black, etc. Examples of the inorganic pigment include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, dark blue, cadmium red, chrome yellow, and metal powder.

As the pigment dispersant, a hydrophilic polymer,
In the natural system, gum arabic, tragum gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch and other plant macromolecules, alginic acid, carrageenan, agar and other seaweed macromolecules, gelatin, casein, albumin. , Animal-based polymers such as collagen, microbial-based polymers such as xanthene gum and dextran, and fibrin-based polymers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and carboxymethyl cellulose in semi-synthetic systems, sodium starch glycolate ,
Starch-based polymers such as sodium starch phosphate, seaweed-based polymers such as sodium alginate and propylene glycol alginate, vinyl-based polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinyl methyl ether, and non-crosslinked Acrylamide, polyacrylic acid and its alkali metal salts, acrylic resins such as water-soluble styrene acrylic resin, water-soluble styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic acid resin, polyvinylpyrrolidone, polyvinyl alcohol, β-naphthalenesulfonic acid formalin condensate alkali metal salt,
Examples thereof include polymer compounds having a side chain with a salt of a cationic functional group such as quaternary ammonium or amino group, and natural polymer compounds such as ceramics.

To the ink of the present invention, conventionally known additives can be added in addition to the above colorant and solvent.

For example, as antiseptic / antifungal agents, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used in the present invention.

As the pH adjuster, any substance can be used as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared.

Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide, and the like. Examples thereof include quaternary phosphonium hydroxide, carbonates of alkali metals such as lithium carbonate, sodium carbonate and potassium carbonate.

Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate.

Examples of the rust preventive agent include acidic sulfite,
Examples include sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

Other water-soluble UV absorbers depending on the purpose,
A water-soluble infrared absorber and a surfactant can also be added.

[0034]

EXAMPLES Examples and comparative examples of the present invention will be shown below.

Example 1 A composition having the following formulation was dissolved by stirring at 60 ° C., allowed to cool at room temperature, and then adjusted to a pH of 7.5 with a 10% aqueous solution of lithium hydroxide. Yellow ink 1 was produced by filtering with a 22 μm Teflon filter.

C. I. Acid Yellow 23 1.2% by weight Glycerol 5% by weight Diethylene glycol 5% by weight Free acid of compound (I) 0.8% by weight Sodium dehydroacetate 0.2% by weight Ion-exchanged water balance Example 2 Other than using the following composition Was carried out in the same manner as in Example 1, and the pH was adjusted to 8.8 with sodium hydroxide to prepare a magenta ink.

C. I. Acid Red 254 1.7% by weight 1,2,6-hexanetriol 8% by weight 1,5-pentanediol 8% by weight Free acid of compound (I) 1.2% by weight Concrete example (II-1) 25% aqueous solution 0.8 wt% 2-Pyridinethiol-1-oxide sodium 0.2 wt% Ion-exchanged water Remaining amount Example 3 pH was set in the same manner as in Example 1 except that the following composition was used.
Was adjusted to 8.5 with lithium hydroxide to prepare a cyan ink.

C. I. Acid blue 249 1.9% by weight N-methyl-2-pyrrolidone 5% by weight Glycerol 2% by weight Propylene glycol monobutyl ether 2% by weight Free acid of compound (I) 0.5% by weight Specific example (II-3) 25% Aqueous solution 0.2% by weight Sodium dehydroacetate 0.2% by weight Ion-exchanged water Remaining amount Example 4 pH was set in the same manner as in Example 1 except that the following composition was used.
Was adjusted to 7.5 with lithium hydroxide to prepare a black ink.

C. I. Food black 2 3.2% by weight Ethylene glycol 5% by weight Glycerol 2% by weight 1,5-pentadiol 10% by weight Free acid of compound (I) 0.8% by weight Concrete example (II-4) 25% aqueous solution 2% by weight % Sodium benzoate 0.2% by weight Ion-exchanged water Remaining amount Example 5 The pH was the same as in Example 1 except that the following composition was used.
Was adjusted to 7.8 with sodium hydroxide to prepare Yellow Ink 2.

Direct Yellow 120 1% by weight Triethylene glycol 5% by weight Petriol 10% by weight Free acid of compound (I) 2% by weight Specific example (II-2) 25% aqueous solution 1.5% by weight ion exchange water residual amount Example 6 The pH was the same as in Example 1 except that the following composition was used.
Was adjusted to 8 with lithium hydroxide to prepare magenta ink 2.

Direct Red 9 1.5% by weight Propylene glycol 8% by weight Glycerol 7% by weight Free acid of compound (I) 2% by weight Specific example (II-7) 25% aqueous solution 1% by weight Ion-exchanged water balance Example 7 In the same manner as in Example 1 except that the following composition was used, pH
Was adjusted to 8 with lithium hydroxide to prepare cyan ink 2.

Direct Blue 199 1.8% by weight N-methyl-2-pyrrolidone 8% by weight 1,5-pentadiol 8% by weight Free acid of compound (I) 0.8% by weight Sodium benzoate 0.1% by weight Ion-exchanged water residual amount Example 8 The same procedure as in Example 1 was repeated except that the following composition was used.
To 7.5 with sodium hydroxide to obtain Black Ink 2.

Direct Black 168 2.8% by weight Thiodiethanol 5% by weight Glycerol 10% by weight Free acid of compound (I) 1.5% by weight 2-propanol 4% by weight Benzoic acid 0.1% by weight Ion-exchanged water Remaining amount Example 9 Air roll OB70 instead of the compound (I) of Example 8
Black Ink 3 was prepared in the same manner except that [Compound (I) 70%, 2-propanol 30%; manufactured by Toho Kagaku] was used.

Comparative Example 1 Yellow ink 3 was prepared in the same manner as in Example 1 except that the compound (I) was omitted.

Comparative Example 2 Magenta Ink 3 was prepared in the same manner as in Example 2 except that the compound (I) was replaced with dodecylbenzenesulfonic acid.

Comparative Example 3 Cyan ink 3 was prepared in the same manner as in Example 3, except that the compound (I) was replaced with sodium di (2-ethylhexyl) sulfosuccinate.

Comparative Example 4 Black ink 4 was obtained in the same manner as in Example 4 except that the 25% aqueous solution of the specific example (II-4) was removed and the ink pH was changed to 4.5.

Comparative Example 5 Yellow Ink 4 was prepared in the same manner as in Example 5, except that the nonionic surfactant BT7 (manufactured by Nikko Chemicals) was used instead of the compound (I).

Comparative Example 6 Magenta Ink 4 was prepared in the same manner as in Example 6 except that the 25% aqueous solution of Concrete Example (II-7) was removed and the pH was adjusted to 8 with potassium hydroxide.

Comparative Example 7 Cyan ink 4 was prepared in the same manner as in Example 7, except that the compound (I) was replaced with dodecylsulfate.

Comparative Example 8 Black ink 5 was prepared in the same manner as in Example 8 except that the nonionic surfactant having acetylene bond, Surfynol 465 (manufactured by Air Product Co.) was used instead of (I).
And

Next, the above Examples 1 to 8 and Comparative Examples 1 to 8
The following test was conducted on

1) Image clarity 300 dp of the thermal ink jet system shown in FIG.
Inkjet printer with i nozzle and FIG.
The laminated PZT shown in Fig. 3 was used to pressurize the liquid chamber channel.
Printing with an inkjet printer having a nozzle of dpi, blurring of the boundary between two color overlapping portions, image blurring, color tone,
The concentration was visually evaluated comprehensively.

Printing paper was printed on three kinds of commercially available recycled paper, high-quality paper and bond paper.

FIG. 3 shows the measurement results of the pixel diameter on each paper of Example 3 and Comparative Example 3.

2) Dryability of image The filter paper was pressed against the image after printing under certain conditions, and the time until the ink was not transferred to the filter paper was measured. When any of the papers was dried within 10 seconds, it was judged as ◯. 3) Storage stability Each ink is put in a polyethylene container and stored at -20 ° C, 5 ° C,
It was stored at 20 ° C. and 70 ° C. under each condition for 3 months, and the surface tension after storage, the viscosity, and the presence or absence of precipitation were examined. The case where there was no change in physical properties, etc. under any conditions of storage was marked as ◯.

4) Reliability at the time of printing suspension It is checked how long the printing can be resumed without the cap, cleaning, etc. during operation of the printer having the head shown in FIG. The results of evaluation of the reliability are shown in the table depending on whether the ejection direction shifts or the weight of the ejected droplet changes.

[0058]

[Table 1]

[0059]

INDUSTRIAL APPLICABILITY According to the present invention, the compound represented by the structural formula (I) is used to improve the wettability with respect to the paper surface, satisfy various properties as an ink jet, have excellent drying property and improve deterioration of image quality. A water-based ink composition can be provided.

According to the present invention, a counter ion of the compound represented by the structural formula (I) is specified to provide an aqueous ink composition part for ink jet which is excellent in storage stability at low temperature and reliability of ejection stability. You can do it.

Further, according to the present invention, by adjusting the pH to 6 or more, an ink jet recording composition which gives physical properties capable of being stably ejected even after long term printing suspension or during continuous ejection is provided.

According to the present invention, an ink composition having excellent properties can be easily provided by mixing an aliphatic alcohol with the compound represented by the structural formula (I).

Further, according to the recording method of the present invention, it is possible to provide a recording method capable of forming a color image which shows good wettability on both so-called plain paper and ink-jet coated paper, has a high permeation rate, and has little bleeding. You can

As described above, according to the present invention, it is possible to stably record a high-quality color image on plain paper, and it is effective in promoting the spread of ink jet color printers.

[Brief description of drawings]

FIG. 1 is a schematic view of an inkjet printer used for evaluation of the ink of the present invention.

FIG. 2 is a schematic view of another inkjet printer of the same.

FIG. 3 is a graph showing measurement results of pixel diameters of the present invention (Example 3) and Comparative Example 3.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C09D 11/02 PTG 7415-4J

Claims (5)

[Claims] 1. An aqueous ink containing a colorant that disperses or dissolves in water, water and a wetting agent, and further contains a compound represented by the following structural formula. [Chemical 1] M: Alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine 2. The counter ion of the compound (I) according to claim 1 is sodium, lithium and / or quaternary ammonium, quaternary phosphonium or alkanolamine cation represented by the following general formula (II). The water-based ink according to claim 1, which is characterized. [Chemical 2] (Y: a nitrogen or phosphorus R ₃ to R _6: hydrogen, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, a halogenated alkyl group) 3. Addition of the compound (I) according to claim 1 in free acid form, and further addition of sodium hydroxide, lithium hydroxide and the hydroxide of counterion (II) according to claim 2. The aqueous ink according to claim 1, wherein the pH is adjusted to 6 to 9 by. 4. The ink according to claim 1, wherein the compound (I) is added to the ink as a mixture containing an aliphatic alcohol. 5. A recording material having a Steckigt sizing degree of 3 seconds or more using the aqueous ink containing the compound (I) according to claim 1 and ejecting it from a fine ejection port to liquefy and fly. A recording method characterized by forming a color image on a sheet.