JP5663863B2 - Water-based ink for ink jet recording, ink cartridge, and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an aqueous inkjet recording ink, an ink cartridge, and an inkjet recording apparatus.

  As a magenta ink for ink jet recording, C.I. I. Acid Red 52 and C.I. I. An ink containing Acid Red 289 is known (see, for example, Patent Document 1). However, the magenta dye has insufficient ozone resistance and light resistance.

Japanese Patent Laid-Open No. 9-137098

  Accordingly, an object of the present invention is to provide a water-based ink for ink jet recording which is excellent in color developability and excellent in ozone resistance and light resistance.

一般式（１）において、
ｎ_１は、１または２であり、
３つのＭは、それぞれ、ナトリウムまたはアンモニウムであり、３つのＭは同一でも異なっていてもよく、
Ｒ_１は、カルボキシ基で置換された炭素原子数１〜８のモノアルキルアミノ基である。

一般式（２）において、
ｒは、０、１または２であり、
Ｒ_２、Ｒ_３およびＲ_４は、それぞれ、置換または無置換のアルキル基、置換または無置換のアルコキシ基、ハロゲン原子、水素原子、ヒドロキシル基、置換または無置換のカルバモイル基、置換または無置換のスルファモイル基、置換または無置換のアミノ基、ニトロ基、スルホン酸エステル基、置換または無置換のアルキルスルホニル基、置換または無置換のアリールスルホニル基、カルボキシ基、カルボン酸エステル基であり、Ｒ_２、Ｒ_３およびＲ_４は同一でも異なっていてもよく、
Ｒ_５、Ｒ_６およびＲ_７は、それぞれ、水素原子、置換または無置換のアルキル基、置換または無置換のアルケニル基、置換または無置換のアリール基、置換または無置換のアラルキル基、置換または無置換の脂環基、置換または無置換のヘテロ環基であり、Ｒ_５、Ｒ_６およびＲ_７は同一でも異なっていてもよい。 In order to achieve the above object, the water-based ink for ink-jet recording of the present invention is a water-based ink for ink-jet recording containing a colorant, water and a water-soluble organic solvent,
The colorant contains the following dye (1) and dye (2).
Dye (1): Dye represented by general formula (1) Dye (2): Dye represented by general formula (2)

In general formula (1),
n ₁ is 1 or 2,
Each of the three Ms is sodium or ammonium, and the three Ms may be the same or different;
R ₁ is a monoalkylamino group having 1 to 8 carbon atoms substituted with a carboxy group.

In general formula (2),
r is 0, 1 or 2;
R ₂ , R ₃ and R ₄ are each a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a hydrogen atom, a hydroxyl group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted group A sulfamoyl group, a substituted or unsubstituted amino group, a nitro group, a sulfonic acid ester group, a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, a carboxy group, a carboxylic acid ester group, R ₂ , R ₃ and R ₄ may be the same or different,
R ₅ , R ₆ and R ₇ are each a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted A substituted alicyclic group, a substituted or unsubstituted heterocyclic group, and R ₅ , R ₆ and R ₇ may be the same or different;

  In order to achieve the above object, the present inventors have made a series of researches. As a result, when the dye (1) and the dye (2) are used in combination in a water-based ink for ink jet recording, the color developability, The present inventors have found that it is excellent in all the properties of ozone and light resistance and have reached the present invention.

FIG. 1 is a schematic perspective view showing an example of the configuration of the ink jet recording apparatus of the present invention.

  The water-based ink for ink-jet recording of the present invention (hereinafter sometimes simply referred to as “water-based ink” or “ink”) will be described. The water-based ink of the present invention contains a colorant, water, and a water-soluble organic solvent. As described above, the colorant includes the dye (1) and the dye (2).

  As described above, the dye (1) is a dye represented by the general formula (1).

As described above, in the general formula (1),
n ₁ is 1 or 2,
Each of the three Ms is sodium or ammonium, and the three Ms may be the same or different;
R ₁ is a monoalkylamino group having 1 to 8 carbon atoms substituted with a carboxy group.
The compound represented by the general formula (1) may be a compound (sodium salt) in which all three M are sodium, or a compound (ammonium salt) in which all three M are ammonium. Further, it may be a compound in which one or two of the three Ms are sodium and the rest are ammonium.
The dye (1) may be composed of a single compound or a mixture containing two or more compounds.
The M may be ionized (at least one of Na ⁺ and NH ₄ ⁺ ) by ionization in water-based ink.

  Preferable specific examples of the dye (1) include compounds represented by the dyes (1-A) to (1-E) shown in Table 1.

  The dye (1) can be produced by a conventionally known method. The method for producing the dye (1) is, for example, as follows.

  That is, first, 1 mol of an anthraquinone compound represented by the structural formula (11) and 1.1 mol to 3 mol of benzoylacetic acid ethyl ester are present in a polar solvent such as xylene and the presence of a basic compound such as sodium carbonate. The reaction is carried out at 130 ° C. to 180 ° C. for 5 hours to 15 hours to obtain the compound represented by the structural formula (12).

  Next, 1 mol of the obtained compound represented by the structural formula (12) and 1 to 5 mol of metaaminoacetamide are mixed in an aprotic polar organic solvent such as N, N-dimethylformamide, and the like. In the presence of a base and a copper catalyst such as copper acetate at 110 ° C. to 150 ° C. for 2 to 6 hours by the Ullmann reaction to obtain a compound represented by the structural formula (13).

  Next, the compound represented by the structural formula (13) thus obtained is sulfonated in 8% to 15% fuming sulfuric acid at 50 ° C. to 120 ° C., and at the same time, by hydrolyzing the acetylamino group, the structure is obtained. A compound represented by the formula (14) is obtained.

Next, 1 mol of the compound represented by the structural formula (14) and 2 mol to 2.5 mol of the compound represented by the structural formula (15) in water at pH 2-9, 2 ° C.-15. The reaction is carried out at 30 ° C. for 30 minutes to 1 hour. A compound represented by the resultant structure (16), the compound corresponding to _{R 1,} i.e. the compound 2 mol to 5 mol, represented by _"R 1 -H" or the like, pH7~10,20 ℃ ~90 By reacting at 10 ° C. for 10 minutes to 10 hours, the dye (1) can be obtained by substituting R ₁ for the leaving group X in the structural formula (16).

  The blending amount of the dye (1) is not particularly limited. By including the dye (1) in the water-based ink, ozone resistance and light resistance can be improved. The blending amount of the dye (1) is, for example, 0.1% by weight to 10% by weight, preferably 1.4% by weight to 5.4% by weight, and more preferably based on the total amount of the water-based ink. Is 1.6 wt% to 4.8 wt%.

  As described above, the dye (2) is a dye represented by the general formula (2).

As described above, in the general formula (2),
r is 0, 1 or 2;
R ₂ , R ₃ and R ₄ are each a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a hydrogen atom, a hydroxyl group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted group A sulfamoyl group, a substituted or unsubstituted amino group, a nitro group, a sulfonic acid ester group, a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, a carboxy group, a carboxylic acid ester group, R ₂ , R ₃ and R ₄ may be the same or different,
R ₅ , R ₆ and R ₇ are each a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted A substituted alicyclic group, a substituted or unsubstituted heterocyclic group, and R ₅ , R ₆ and R ₇ may be the same or different;

In the general formula (2), the substituted or unsubstituted alkyl group in R ₂ , R ₃ and R ₄ is preferably an alkyl group having 1 to 9 carbon atoms in total. Examples of the substituted or unsubstituted alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a trifluoromethyl group, and a dimethylaminomethyl group. Examples of the substituent of the substituted alkyl group include hydroxyl group; alkoxy group such as methoxy group and ethoxy group; cyano group; halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; carboxylate salt and sulfonic acid Examples thereof include ionic hydrophilic groups such as salts.

In the general formula (2), the substituted or unsubstituted alkoxy group in R ₂ , R ₃ and R ₄ is preferably an alkoxy group having 1 to 9 carbon atoms in total. Examples of the substituted or unsubstituted alkoxy group include a methoxy group, an isopropoxy group, and an n-butoxy group.

In the general formula (2), examples of the halogen atom in R ₂ , R _3, and R ₄ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the general formula (2), examples of the substituted or unsubstituted carbamoyl group in R ₂ , R ₃ and R ₄ include a carbamoyl group, an N, N-dimethylcarbamoyl group, and a phenylcarbamoyl group.

In the general formula (2), examples of the substituted or unsubstituted sulfamoyl group in R ₂ , R ₃ and R ₄ include a sulfamoyl group, an N-methylsulfamoyl group, an N-ethylsulfamoyl group, and an N-ethyl group. -N-phenylsulfamoyl group, N, N-dimethylsulfamoyl group, p-carboxyphenylsulfamoyl group and the like can be mentioned.

In the general formula (2), examples of the substituted or unsubstituted amino group in R ₂ , R ₃ and R ₄ include an N-methylamino group, a carbamoylamino group, an N, N-diethylamino group, and an acetylamino group. can give.

In the general formula (2), examples of the sulfonate group in R ₂ , R ₃ and R ₄ include a phenoxysulfonyl group.

In the general formula (2), the substituted or unsubstituted alkylsulfonyl group in R ₂ , R ₃ and R ₄ is preferably an alkylsulfonyl group having 1 to 9 carbon atoms in total. Examples of the substituted or unsubstituted alkylsulfonyl group include a hydroxysulfonyl group.

In the general formula (2), the substituted or unsubstituted arylsulfonyl group in R ₂ , R ₃ and R ₄ is preferably an arylsulfonyl group having 6 to 15 carbon atoms in total. Examples of the substituted or unsubstituted arylsulfonyl group include a benzylsulfonyl group.

In the general formula (2), examples of the carboxylic acid ester group in R ₂ , R ₃ and R ₄ include a methoxycarbonyl group.

In the general formula (2), the substituted or unsubstituted alkyl group in R ₅ , R ₆ and R ₇ is preferably an alkyl group having 1 to 18 carbon atoms in total. Examples of the substituted or unsubstituted alkyl group include an ethyl group, an n-butyl group, an n-octyl group, an ethylhexyl group, a hydroxyethyl group, a carboxypropyl group, a carboxycyclohexylmethyl group, and 1-carboxy-2-mercaptoethyl. Group, 1-carboxy-2-carbamoyl-ethyl group, 1-isopropyl-1-carboxymethyl group, 1,2-dicarboxypropyl group and the like. Examples of the substituent of the substituted alkyl group include hydroxyl group; alkoxy group such as methoxy group and ethoxy group; cyano group; halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; carboxylate salt and sulfonic acid Examples thereof include ionic hydrophilic groups such as salts.

In the general formula (2), the substituted or unsubstituted alkenyl group in R ₅ , R ₆ and R ₇ is preferably an alkenyl group having 2 to 18 carbon atoms in total. Examples of the substituted or unsubstituted alkenyl group include 2-methyl-1-propenyl group, vinyl group, allyl group and the like.

In the general formula (2), examples of the substituted or unsubstituted aryl group in R ₅ , R ₆ and R ₇ include a 3,4-dicarboxyphenyl group, a 4-butylphenyl group, and a 4-carboxyphenyl group. can give. Examples of the substituent of the substituted aryl group include the same substituents as the substituent of the substituted alkyl group.

In the general formula (2), examples of the substituted or unsubstituted aralkyl group in R ₅ , R ₆ and R ₇ include benzyl group, 1-carboxy-2-phenyl-ethyl group, 1-carboxy-2-hydroxyphenyl Examples thereof include an ethyl group and a 4-carboxybenzyl group.

In the general formula (2), examples of the substituted or unsubstituted alicyclic group in R ₅ , R ₆ and R ₇ include a cyclohexyl group and a 4-carboxycyclohexyl group.

In the general formula (2), examples of the substituted or unsubstituted heterocyclic group in R ₅ , R _6, and R ₇ include a pyridyl group, a thiadiazolyl group, a benzothiazolyl group, 2,2,6,6-tetramethylpiperidi And a nyl group. Examples of the substituent of the substituted heterocyclic group include the same substituents as the substituent of the substituted alkyl group.

In the general formula (2), R ₅ , R ₆ and R ₇ are each an alkyl group, alkenyl group, aryl group, alicyclic group, aralkyl, at least one of which is substituted with 1 to 4 carboxy groups or sulfamoyl groups. It may be a group or a heterocyclic group.

In the general formula (2), R ₅ and R ₆ may each be a hydrogen atom or a trisubstituted phenyl group, and R ₅ and R ₆ may be the same or different. Here, the three substituents of the 3-substituted phenyl group are each a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group having 1 to 9 total carbon atoms, and a total number of 1 to 9 carbon atoms. A substituted or unsubstituted alkoxy group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted amino group, a nitro group, a sulfonate group, or a carboxylate group, The two substituents may be the same or different.

A preferred embodiment of the dye (2) is, for example, an alkyl group in which at least one of R ₅ , R ₆ and R ₇ is substituted with 1 to 4 carboxy groups or sulfamoyl groups in the general formula (2). , An alkenyl group, an aryl group, an aralkyl group, or a cyclohexyl group.

  The dye (2) preferably has a total of 6 or less, preferably 5 or less, particularly preferably 4 or less sulfonic acid groups and carboxy groups or salts thereof in the structure. Moreover, although the said dye (2) may be used with a free acid form, when obtained with a salt form at the time of manufacture, you may use as it is and may convert into a desired salt form. The dye (2) may have a part of the acid group in a salt form, and may contain a salt-type dye and a free acid-type dye. Examples of such salt forms include salts of alkali metals such as Na, Li and K, ammonium salts which may be substituted with alkyl groups or hydroxyalkyl groups, and organic amine salts. Examples of the organic amine include lower alkyl amines, hydroxy substituted lower alkyl amines, carboxy substituted lower alkyl amines, 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.

As a preferable aspect of the dye (2), for example, in the general formula (2),
r is 0;
R ₂ is a carboxy group, a carbamoyl group, a trifluoromethyl group or a sulfamoyl group,
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a phenyl group or a carboxyalkyl group which may be substituted with a carboxy group or a sulfamoyl group,
In an embodiment, R ₇ is a hydrogen atom or an alkyl group.

  Preferable specific examples of the dye (2) include compounds represented by chemical formulas (2-A) to (2-E).

The compound represented by the chemical formula (2-A) is represented by the general formula (2):
r is 0;
R ₂ is a carboxy group located at the 2-position of the phenyl group bonded to the azo group,
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a 2-carboxyphenyl group;
In an embodiment, R ₇ is a hydrogen atom. In the compound represented by the chemical formula (2-A), the sulfonic acids located at the 3rd and 6th positions of the naphthalene ring are ammonium salts.

In the general formula (2), the compound represented by the chemical formula (2-B)
r is 0;
R ₂ is a carbamoyl group located at the 2-position of the phenyl group bonded to the azo group;
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a 2-carboxyphenyl group;
In an embodiment, R ₇ is a hydrogen atom. In the compound represented by the chemical formula (2-B), the sulfonic acids located at the 3rd and 6th positions of the naphthalene ring are sodium salts.

In the general formula (2), the compound represented by the chemical formula (2-C)
r is 0;
R ₂ is a sulfamoyl group located at the 3-position of the phenyl group bonded to the azo group;
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a 2-sulfamoylphenyl group,
In an embodiment, R ₇ is an isopropyl group. In the compound represented by the chemical formula (2-C), the sulfonic acids located at the 3rd and 6th positions of the naphthalene ring are ethylammonium salts.

In the general formula (2), the compound represented by the chemical formula (2-D)
r is 0;
R ₂ is a trifluoromethyl group located at the 2-position of the phenyl group bonded to the azo group,
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a 1-carboxy-2-methylbutyl group,
In an embodiment, R ₇ is a methyl group. In the compound represented by the chemical formula (2-D), the sulfonic acids located at the 3rd and 6th positions of the naphthalene ring are methylammonium salts.

In the general formula (2), the compound represented by the chemical formula (2-E)
r is 0;
R ₂ is a carboxy group located at the 2-position of the phenyl group bonded to the azo group,
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a phenyl group;
In an embodiment, R ₇ is a hydrogen atom. In the compound represented by the chemical formula (2-E), the sulfonic acids located at the 3rd and 6th positions of the naphthalene ring are ammonium salts.

  The dye (2) can be produced by a conventionally known method. An example of the method for producing the dye (2) is shown in the following steps (A) to (C).

Process (A)
First, 2-aminobenzoic acid (anthranilic acid) and 1-amino-8-hydroxy-3,6-naphthalenedisulfonic acid (H acid) are used in conventional methods (for example, “New dye chemistry” by Yutaka Hosoda (Showa 48) The monoazo compound is produced through diazotization and coupling reaction according to December 21, published by Gihodo) (see pages 396 to 409).

Process (B)
Next, the obtained monoazo compound is added to the cyanuric chloride suspension and reacted for several hours. At this time, the pH of the reaction solution is maintained at 4-6 and the temperature at 0 ° C-5 ° C. Following this reaction, a 2-aminobenzoic acid (anthranilic acid) aqueous solution is added to the reaction solution so that the liquid does not become alkaline at room temperature, and a condensation reaction is performed for several hours. Subsequently, a hydrolysis reaction is performed by adding a 25% aqueous sodium hydroxide solution at a reaction solution temperature of 50 ° C. to 60 ° C. to make it strongly alkaline, thereby completing the reaction.

Process (C)
After completion of the reaction, the reaction solution is cooled and salted out with sodium chloride to obtain the dye (2).

  The blending amount of the dye (2) is not particularly limited. By including the dye (2) in the water-based ink, the color developability can be improved. The blending amount of the dye (2) is, for example, 0.05% to 5% by weight, preferably 0.2% to 1.8% by weight, and more preferably based on the total amount of the water-based ink. Is 0.4 wt% to 1.2 wt%.

  The weight ratio of the dye (1) and the dye (2) in the water-based ink is preferably dye (1): dye (2) = 70: 30 to 90:10. By setting the weight ratio within the above range, it is possible to obtain a water-based ink that has excellent color developability, ozone resistance, and light resistance.

  The total blending amount of the dye (1) and the dye (2) is not particularly limited, but is preferably 2% by weight to 6% by weight with respect to the total amount of the water-based ink. By setting the total blending amount within the above range, it is possible to obtain a water-based ink with extremely good color development, ozone resistance, light resistance and jetting stability.

  In addition to the dye (1) and the dye (2), the colorant may further contain other dyes and pigments.

  The water is preferably ion exchange water or pure water. The blending amount (water ratio) of the water with respect to the total amount of the water-based ink is, for example, 10% to 90% by weight, and preferably 40% to 80% by weight. The said water ratio is good also as the remainder of another component, for example.

  Examples of the water-soluble organic solvent include a wetting agent that prevents drying of the water-based ink at the nozzle tip of the ink jet head and a penetrating agent that adjusts the drying speed on the recording medium.

  The wetting agent is not particularly limited, and examples thereof include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, dimethylacetamide Amides such as acetone; Ketones such as acetone; Keto alcohols such as diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; Polyhydric alcohols such as polyalkylene glycol, alkylene glycol and glycerin; 2-pyrrolidone; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone and the like. Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol. Examples of the alkylene glycol include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. These wetting agents may be used alone or in combination of two or more. Among these, polyhydric alcohols such as alkylene glycol and glycerin are preferable.

  The blending amount (humectant ratio) of the wetting agent with respect to the total amount of the water-based ink is, for example, 0% by weight to 95% by weight, preferably 5% by weight to 80% by weight, and more preferably 5% by weight. ~ 50% by weight.

  Examples of the penetrant include glycol ether. Examples of the glycol ether include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n- Hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, Propylene glycol-n-butyl ether , Dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether And tripropylene glycol-n-butyl ether. The said penetrant may be used individually by 1 type, and may use 2 or more types together.

  The blending amount (permeating agent ratio) of the penetrant with respect to the total amount of the water-based ink is, for example, 0 wt% to 20 wt%. By setting the penetrant ratio within the above range, the penetrability of the water-based ink into the recording medium can be made more suitable. The penetrant ratio is preferably 0.1% by weight to 15% by weight, and more preferably 0.5% by weight to 10% by weight.

  The water-based ink may further contain a conventionally known additive as required. Examples of the additive include a surfactant, a pH adjuster, a viscosity adjuster, a surface tension adjuster, and an antifungal agent. Examples of the viscosity modifier include polyvinyl alcohol, cellulose, and a water-soluble resin.

  The water-based ink is obtained by, for example, uniformly mixing a colorant, water, a water-soluble organic solvent, and, if necessary, other additive components by a conventionally known method, and removing insoluble matters with a filter or the like. Can be prepared.

  The aqueous ink of the present invention can be used as, for example, an aqueous magenta ink. However, the present invention is not limited to this. The water-based ink of the present invention can be a water-based ink having a color other than magenta by using a colorant other than the dye (1) and the dye (2).

  Next, the ink cartridge of the present invention will be described. The ink cartridge of the present invention is an ink cartridge containing a water-based ink for ink-jet recording, and the water-based ink is the water-based ink for ink-jet recording of the present invention. As the main body of the ink cartridge, for example, a conventionally known one can be used.

  Next, the ink jet recording apparatus of the present invention will be described. The ink jet recording apparatus of the present invention is an ink jet recording apparatus that includes an ink storage portion and an ink discharge means, and discharges the ink stored in the ink storage portion by the ink discharge means. The ink cartridge is accommodated. Except for this, the configuration of the ink jet recording apparatus of the present invention may be the same as that of a conventionally known ink jet recording apparatus, for example.

  FIG. 1 shows the configuration of an example of the ink jet recording apparatus of the present invention. As shown in the figure, this ink jet recording apparatus 1 includes four ink cartridges 2, an ink discharge means (ink jet head) 3, a head unit 4, a carriage 5, a drive unit 6, a platen roller 7, and a purge device 8. Are included as main components.

  The four ink cartridges 2 contain one color each of four colors of water-based inks of yellow, magenta, cyan, and black. For example, an ink cartridge containing the water-based magenta ink is the ink cartridge of the present invention. The ink jet head 3 performs recording on a recording medium P such as recording paper. The head unit 4 includes the inkjet head 3. The four ink cartridges 2 and the head unit 4 are mounted on the carriage 5. The drive unit 6 reciprocates the carriage 5 in a linear direction. For example, a conventionally known drive unit 6 can be used as the drive unit 6 (see, for example, Japanese Patent Application Laid-Open No. 2008-246821). The platen roller 7 extends in the reciprocating direction of the carriage 5 and is disposed to face the ink jet head 3. The recording includes printing, printing, printing, and the like.

  The recording medium P is fed from a paper feed cassette (not shown) provided on the side of or below the ink jet recording apparatus 1. The recording medium P is introduced between the inkjet head 3 and the platen roller 7. Then, predetermined recording is performed on the recording medium P by the ink ejected from the inkjet head 3. Thereafter, the recording medium P is discharged from the inkjet recording apparatus 1. In FIG. 1, the paper feed mechanism and paper discharge mechanism of the recording medium P are not shown.

  The purge device 8 sucks out defective ink containing bubbles and the like accumulated in the ink jet head 3. As the purge device 8, for example, a conventionally known device can be used (see, for example, Japanese Patent Application Laid-Open No. 2008-246821).

  A wiper member 20 is disposed adjacent to the purge device 8 at a position on the platen roller 7 side of the purge device 8. The wiper member 20 is formed in a spatula shape, and wipes the nozzle forming surface of the inkjet head 3 as the carriage 5 moves. In FIG. 1, a cap 18 covers a plurality of nozzles of the inkjet head 3 that are returned to the reset position when recording is completed in order to prevent ink from drying.

  In the ink jet recording apparatus, the four ink cartridges may be mounted on a plurality of carriages. Further, the ink cartridge may not be mounted on the carriage but may be arranged and fixed in the ink jet recording apparatus. In this aspect, for example, the ink cartridge and the head unit mounted on the carriage are connected by a tube or the like, and the ink is supplied from the ink cartridge to the head unit.

Next, examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples.

[Examples 1 to 9 and Comparative Examples 1 to 6]
The ink composition components (Table 2) were mixed uniformly. Thereafter, the obtained mixture was filtered using a hydrophilic polytetrafluoroethylene (PTFE) type membrane filter (pore diameter 0.20 μm) manufactured by Toyo Roshi Kaisha, Ltd., so that Examples 1 to 9 and Comparative Example 1 were used. -6 water-based inks for inkjet recording were obtained. In Table 2, dyes (1-A) to (1-E) are compounds represented by dyes (1-A) to (1-E) shown in Table 1, respectively, and dyes (2- A) to (2-E) are compounds represented by chemical formulas (2-A) to (2-E), respectively.

  For the water-based inks of Examples and Comparative Examples, (a) color development evaluation, (b) ozone resistance evaluation, (c) light resistance evaluation, (d) jetting stability evaluation, and (e) comprehensive evaluation are described in the following methods. It went by. Samples used for (a) color development evaluation, (b) ozone resistance evaluation, and (c) light resistance evaluation were prepared as follows.

  First, the ink cartridges were filled with the aqueous inks of Examples and Comparative Examples. Next, the ink cartridge was mounted on a digital multifunction device DCP-385C equipped with an inkjet printer manufactured by Brother Industries, Ltd. Next, the gradation sample of the water-based ink was printed on photographic glossy paper BP71GA manufactured by Brother Industries.

(A) Evaluation of color developability The gradation sample was visually observed to evaluate whether the magenta color was sufficiently expressed according to the following evaluation criteria.

Evaluation of color developability Evaluation criteria A: The magenta color is sufficiently expressed.
B: A magenta color can be expressed.
C: The magenta color cannot be expressed.

(B) Ozone resistance evaluation Among the gradation samples, a patch having an initial OD value of 1.0 was used as an evaluation sample. The OD value was measured with a spectrocolorimeter Spectrolino (light source: D ₆₅ ; field of view: 2 °; status A) manufactured by Gretag Macbeth. Using the ozone weather meter OMS-H manufactured by Suga Test Instruments Co., Ltd., the patch was allowed to stand for 40 hours under the conditions of an ozone concentration of 1 ppm, a bath temperature of 24 ° C., and a bath relative humidity of 60%. Subsequently, the OD value of the patch after the standing was measured in the same manner as described above. Next, the OD value reduction rate (%) was obtained by the following formula (I), and the ozone resistance was evaluated according to the following evaluation criteria. Note that the smaller the OD value reduction rate, the less the deterioration of image quality and the better the ozone resistance.

OD value decrease rate (%) = {(XY) / X} × 100 (I)
X: 1.0 (initial OD value)
Y: OD value after standing

Evaluation of ozone resistance Evaluation standard A: OD value decrease rate is less than 20% B: OD value decrease rate is 20% or more and less than 30% C: OD value decrease rate is 30% or more and less than 40% D: OD value decrease Rate is 40% or more

(C) Light resistance evaluation Among the gradation samples, a patch having an initial OD value of 1.0 was used as an evaluation sample. The OD value was measured with a spectrocolorimeter Spectrolino (light source: D ₆₅ ; field of view: 2 °; status A) manufactured by Gretag Macbeth. Using a Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd., the patch was irradiated with xenon lamp light for 100 hours under the conditions of a bath temperature of 23 ° C., a bath relative humidity of 50%, and an illuminance of 81 klx. Subsequently, the OD value of the patch after the irradiation was measured in the same manner as described above. Next, the OD value reduction rate (%) was determined by the following formula (II), and the light resistance was evaluated according to the following evaluation criteria. Note that the smaller the OD value reduction rate, the less the image quality is deteriorated and the better the light resistance.

OD value reduction rate (%) = {(XY) / X} × 100 (II)
X: 1.0 (initial OD value)
Y: OD value after irradiation

Light resistance evaluation Evaluation standard A: OD value reduction rate is less than 20% B: OD value reduction rate is 20% or more and less than 30% C: OD value reduction rate is 30% or more and less than 40% D: OD value reduction rate But over 40%

(D) Evaluation of jetting stability Using a digital multifunction device DCP-385C equipped with an inkjet printer manufactured by Brother Industries, Ltd., 100 million dots (about 3 Million) continuous recording. The results of the continuous recording were evaluated according to the following evaluation criteria. Non-ejection is a state in which the nozzles of the inkjet head are clogged and the water-based ink is not ejected. The discharge bend is a state in which a part of the nozzles of the ink jet head is clogged and the water-based ink is not discharged perpendicularly to the recording paper but is discharged obliquely.

Evaluation of jetting stability Evaluation standard A: During continuous recording, there was no non-ejection and no ejection bending.
B: During continuous recording, there was a slight non-ejection or ejection curve, but the non-ejection or ejection curve was recovered by purging 5 times or less.
C: During continuous recording, there were many non-ejections and ejection bends, and both the non-ejections and ejection bends were not recovered by 5 purges.

(E) Comprehensive evaluation About each water-based ink, comprehensive evaluation was performed according to the following evaluation criteria from the results of (a) to (d).

Overall Evaluation Evaluation Criteria G: All evaluation results were A or B.
NG: C or D was found in any of the evaluation results.

  Table 2 shows the compositions and evaluation results of the water-based inks of Examples and Comparative Examples.

  As shown in Table 2, the evaluation results were good in the examples in which the dye (1) and the dye (2) were used in combination. In Examples 1 to 5 in which the weight ratio between the dye (1) and the dye (2) is different, Examples 2 to 4 where the dye (1): the dye (2) = 70: 30 to 90:10 (weight ratio) are used. The color developability, ozone resistance and light resistance were both very good. In Examples 6 to 9 in which the total amount of dyes is different, in Examples 7 and 8 in which the total amount of dyes is 2 to 6% by weight, both ozone resistance and light resistance and jet stability are extremely high. It was good.

  On the other hand, in the comparative example 1 which does not contain dye (2), the color developability was inferior. In Comparative Example 2 not containing the dye (1), ozone resistance and light resistance were inferior. In place of the dye (2), C.I. I. In Comparative Example 3 using Acid Red 52, ozone resistance and light resistance were inferior. In place of the dye (2), C.I. I. In Comparative Example 4 using Acid Red 289, ozone resistance and light resistance were inferior. In place of the dye (1), C.I. I. In Comparative Example 5 using Acid Red 52, ozone resistance and light resistance were remarkably inferior. In place of the dye (1), C.I. I. In Comparative Example 6 using Acid Red 289, ozone resistance and light resistance were remarkably inferior.

  As described above, the water-based ink of the present invention is excellent in all the performances of color development, ozone resistance and light resistance. The use of the water-based ink of the present invention is not particularly limited, and can be widely applied to various ink jet recordings.

DESCRIPTION OF SYMBOLS 1 Inkjet recording apparatus 2 Ink cartridge 3 Ink discharge means (inkjet head)
4 Head unit 5 Carriage 6 Drive unit 7 Platen roller 8 Purge device

Claims (5)

A water-based ink for inkjet recording comprising a colorant, water and a water-soluble organic solvent,
The water-soluble organic solvent comprises dipropylene glycol-n-propyl ether;
The colorant includes the following dye (1) and dye (2),
The weight ratio of the dye (1) and the dye (2) in the water-based ink is dye (1): dye (2) = 70: 30 to 90:10,
A water-based ink for ink-jet recording, wherein the total amount of the dye (1) and the dye (2) is 2% by weight to 6% by weight with respect to the total amount of the water-based ink.
Dye (1): Dye represented by general formula (1) Dye (2): Dye represented by general formula (2)

In general formula (1),
n ₁ is 1 or 2,
Each of the three Ms is sodium or ammonium, and the three Ms may be the same or different;
R ₁ is a monoalkylamino group having 1 to 8 carbon atoms substituted with a carboxy group.

In general formula (2),
r is 0, 1 or 2;
R ₂ , R ₃ and R ₄ are each a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen atom, a hydrogen atom, a hydroxyl group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted group. A sulfamoyl group, a substituted or unsubstituted amino group, a nitro group, a sulfonate group, a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, a carboxy group, a carboxylate group, R ₂ , R ₃ and R ₄ may be the same or different,
R ₅ , R ₆ and R ₇ are each a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, substituted or unsubstituted A substituted alicyclic group, a substituted or unsubstituted heterocyclic group, and R ₅ , R ₆ and R ₇ may be the same or different; The blending amount (X) of the dye (2) with respect to the total amount of the water-based ink and the blending amount (Y) of dipropylene glycol-n-propyl ether with respect to the total amount of the water-based ink are X: Y (weight ratio) = 0. 2: 1 to 0.6: the aqueous inkjet recording ink according to claim 1, wherein satisfying 1. In general formula (2),
r is 0;
R ₂ is a carboxy group, a carbamoyl group, a trifluoromethyl group or a sulfamoyl group,
R ₃ , R ₄ and R ₆ are each a hydrogen atom,
R ₅ is a phenyl group or a carboxyalkyl group which may be substituted with a carboxy group or a sulfamoyl group,
R ₇ is, water-based inkjet recording ink according to claim 1 or 2 is a hydrogen atom or an alkyl group. An ink cartridge containing a water-based ink for inkjet recording, wherein the water-based ink is

An ink cartridge comprising the water-based ink for ink jet recording according to any one of claims 1 to 3 . An ink jet recording apparatus that includes an ink storage unit and an ink discharge unit, and discharges ink stored in the ink storage unit by the ink discharge unit, wherein the ink storage unit stores the ink cartridge according to claim 4. An ink jet recording apparatus.

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