JP2003277655A - Ink composition for inkjet recording and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ink composition for inkjet recording which has no color bleeding, no feathering, slight print through, high coloring, high quality and high reliability of clogging on a recording image in inkjet printing and to provide an ink composition set, an ink cartridge, an inkjet recorder and a recorder method, and to obtain an image. <P>SOLUTION: The ink composition comprises (A) pigment, (B) alginic acid or an alginate having pH 7.0 and ≤5 mPa.s viscosity of 10 wt.% aqueous solution, (C) a wetting agent, (D) a ≥8C and ≤11C polyol or glycol ether, (E) an anionic or nonionic surfactant and (F) water. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition for ink jet recording, and more specifically, it pays attention to the ink composition, particularly alginic acid, and realizes high color development and high image quality printing on plain paper, and color bleeding and feathering. The present invention relates to an ink composition, an ink composition set, a cartridge, an inkjet recording apparatus, an inkjet recording method, and an image formed that can reduce or eliminate rings and strikethrough.

[0002]

2. Description of the Related Art For ink jet recording, inks of various compositions have been proposed. As a recent trend, especially when printed on a paper generally called plain paper including copy paper and recycled paper, importance is attached to quality. The quality required for plain paper printing is that the printed matter has high image quality (without feathering) and high coloring on the one hand, and on the other hand, bleeding caused by the contact of multiple color recording inks ( That is, there is no color bleed). Generally, it is preferable to suppress the ink permeability to improve high image quality and color developability, but it is preferable to increase the ink permeability to reduce or eliminate the color bleeding.

Various inks have been proposed to solve these problems. For example, Japanese Patent Laid-Open No. 54-
In JP 62005, alginic acid and polyethylene glycol are added to the ink to enable the wetting effect and viscosity adjustment.

Further, in JP-A-5-194884, a polymer colloid and at least one surfactant having a critical micelle concentration or more and a low vapor pressure solvent are added to the ink,
It is disclosed that bleeding on recording paper is reduced.

On the other hand, in JP-A-6-88048,
Using a recording ink in which the amount of surfactant added is greater than or equal to the critical micelle concentration with respect to the ink and less than or equal to the critical micelle concentration with respect to pure water, the effect of the surfactant causes bleeding between the recording medium and the ink and bleeding of color boundaries. Is said to have prevented.

[0006]

However, the above-mentioned conventional techniques have not sufficiently solved the contradictory problems. Specifically, the following issues remained.

First, feathering occurs in the recorded image, and the coloration of the recorded image is low. That is, since the surface tension of the ink is remarkably reduced in order to improve the penetrability for the purpose of improving the feathering and color bleeding of the recorded image, the ink that has landed on the recording paper is dispersed in the fine pores existing between the paper fibers. It penetrates by the capillary phenomenon and penetrates deeply inside the paper. Therefore, the dot shape of the landed ink on the recording medium lacks sharpness around the dots, the edges of the recorded image are blurred, and the strikethrough is large, which is an obstacle to increasing the resolution of the recorded image. There is. At the same time, there is a problem that the color development of the recorded image is deteriorated.

Generally, by suppressing the ink permeability, it is possible to enhance the color developability of a recorded image and to sharpen the landed dot shape. However, the ink whose permeation is suppressed has a lower drying property on the recording medium. Therefore, when a plurality of inks are used as in color printing, the ink remaining on the recording medium without being dried remains. When they are mixed with each other, color bleeding occurs and the image quality is deteriorated. As described above, with the conventional ink, the recording quality on plain paper is still insufficient.

The second problem is that the print head nozzles are clogged. JP-A-5-19488
Since the ink described in Japanese Patent Publication No. 4 contains a polymer colloid, unless printing is performed for a long period of several days or more, the water content of the ink evaporates in the vicinity of the nozzle, the polymer compound concentration increases, and the ink The viscosity rises sharply, and the polymer compound precipitates. If printing is performed at the next opportunity in such a state, the ink cannot be properly ejected due to clogging of the nozzles of the head, resulting in a marked deterioration in print quality.

Therefore, an object of the present invention is to use an ink containing a specific alginic acid and a pigment, a wetting agent, a polyol or a glycol ether, and a surfactant.
When feathering, color bleeding of mixed colors, and strike-through are reduced or eliminated on the recording medium, and when these are satisfied, the print quality is sharp and clear, especially on plain paper, and the recorded image has high color development and the head An object of the present invention is to provide an inkjet recording ink and a recording method that do not cause nozzle clogging.

[0011]

The above object of the present invention can be achieved by the following means. According to the invention, claim 1
Then at least (A) pigment, (B) pH 7.0 10w
Ultra low viscosity alginic acid and / or alginate having a viscosity of t% aqueous solution of 5 mPa · s or less (20 ° C.), (C) wetting agent, (D) polyol or glycol ether having 8 to 11 carbon atoms, (E) anion Alternatively, the most main feature is to be achieved by an ink composition for inkjet recording, which comprises a nonionic surfactant and (F) water.

Secondly, the ink composition according to claim 1, wherein the alginic acid or alginate is 0.1 to 3.0 w of the total amount of the ink.
The main feature is to contain t%.

Thirdly, the ink composition according to claim 1 or 2, wherein the alginic acid, an alkali metal hydroxide, an alkanolamine, and a quaternary ammonium substituted with at least one or more hydroxyl groups, amino. The main feature is to have at least one selected from alcohols.

Fourth, the ink composition according to any one of claims 1 to 3, wherein the alkali metal hydroxide is sodium hydroxide, potassium hydroxide or lithium hydroxide. That is the main feature.

Fifth, the ink composition according to any one of claims 1 to 3 is characterized mainly in that the alkanolamine according to claim 3 is triethanolamine.

Sixth, the ink composition according to any one of claims 1 to 3, wherein the amino alcohol according to claim 3 is 2-amino-2-methyl-1,3-propanediol. , 2-amino-2-ethyl-1,3-propanediol or 2-amino-2-hydroxymethyl-
Its main feature is that it is 1,3-propanediol.

Seventh, the ink composition according to any one of claims 1 to 3, wherein the quaternary ammonium substituted with at least one hydroxyl group according to claim 3 is the structural formula. (1) That is, trimethyl-2-hydroxyethylammonium hydroxide, (2) that is trimethyl-2-hydroxyethoxyammonium hydroxide, and (3) that is trimethyl-2- (2-hydroxyethoxy) ethoxyammonium hydroxide. That is the main feature.

Eighth, the ink composition according to any one of claims 1 to 7, wherein the ratio of D-mannuronic acid and L-guluronic acid constituting alginic acid as the alginic acid (B). (D-mannuronic acid / L-guluronic acid)
Is characterized by using alginic acid in the range of 0.05 to 0.8.

Ninth, the ink composition according to any one of claims 1 to 7, wherein the alginic acid (B) is a ratio of D-mannuronic acid and L-guluronic acid constituting alginic acid. (D-mannuronic acid / L-guluronic acid)
Is mainly characterized by using alginic acid in the range of 1.5 to 2.5.

Tenth, the ink composition according to any one of claims 1 to 9, wherein the weight ratio of the alginic acid or alginate (B) to the wetting agent (C) is from 1:10. The main feature is 1:50.

Eleventh, the ink composition according to any one of claims 1 to 10, wherein the polyol or glycol ether is 2-ethyl-1,3-hexanediol or 2,2,4. A major feature is that it is trimethyl-1,3-pentanediol.

Twelfth, the ink composition according to any one of claims 1 to 11, wherein the anionic or nonionic surfactant is represented by the general formula (4), (5),
The main feature is that it is at least one selected from the surfactants of (6), (7), (8) and (9).

Thirteenth, the ink composition according to any one of claims 1 to 12, which contains 0.1 to 5.0 wt% of the anionic or nonionic surfactant. Is characterized by.

Fourteenth, the ink composition according to any one of the first to thirteenth aspects is characterized in that the wetting agent is a solid wetting agent.

Fifteenth, the ink composition according to claim 14, wherein the solid wetting agent (G) is contained in an amount of 0.5 to 30 wt% of the ink composition. And

Sixteenth, the ink composition according to any one of claims 1 to 15, wherein the wetting agent (G) is used.
Is glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butane Diol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 1,
Its main feature is that it comprises at least one selected from 2,4-butanetriol, 1,2,6-hexanetriol, trimethylolpropane, trimethylolethane, thiodiglycol and pentaerythritol.

Seventeenth, the ink composition according to any one of claims 1 to 16, wherein the wetting agent is a wetting agent obtained by mixing glycerin and a wetting agent other than glycerin. Characterize.

Eighteenth, the ink composition according to any one of claims 1 to 17, wherein the wetting agent is added in an amount of 5 to 4
The main feature is to contain 0 wt%.

Nineteenth, the ink composition according to any one of claims 1 to 18, wherein the pigment concentration is 5 to
The main feature is 15 wt%.

In a twentieth aspect, the ink composition according to any one of claims 1 to 19 is characterized mainly in that the pigment is a self-dispersion pigment.

The twenty-first aspect is the ink composition according to the twentieth aspect, which is characterized mainly in that the self-dispersion pigment has a carboxyl group, a sulfone group, a carbonyl group or a hydroxyl group on the surface.

Twenty-second, the ink composition according to claim 20 or 21, wherein at least one hydrophilic group is treated with a diazo compound, an oxidation treatment, or a hypochlorous acid treatment on the surface of the self-dispersion pigment. Its main feature is that it is contained by any one of treatment with a sulfonating agent and treatment with humic acid.

A twenty-third feature of the ink composition according to any one of claims 20 to 22 is that the self-dispersion pigment has an average particle diameter of 0.16 µm or less. To do.

Twenty-fourth, the ink composition according to any one of claims 1 to 23, wherein the weight ratio of the wetting agent to the pigment is 0.3 to 8.0. Characterize.

[0035] In a twenty-fifth aspect, the ink composition according to any one of claims 1 to 24, comprising 2-pyrrolidone,
N-methyl-2-pyrrolidone, N-hydroxyethyl-
The main feature is that it contains at least one selected from 2-pyrrolidone and ε-caprolactam.

The twenty sixth aspect of the present invention is the ink composition according to any one of the first to twenty fifth aspects, wherein the ink has a viscosity of 8 or less.
The main feature is that it is ˜20 mPa · s (25 ° C.).

Twenty-seventh, a color ink jet recording ink composition set, comprising a color ink composition of two or more colors, wherein at least one of the ink compositions is used. Is an ink composition according to any one of claims 1 to 26.

A twenty-eighth aspect of the present invention is an ink cartridge, which is characterized mainly in that the ink composition according to any one of the first to twenty-sixth aspects is contained.

Twenty-ninth, in an ink jet recording ink cartridge, an ink cartridge for ink jet recording has an ink containing portion containing ink and a recording head portion for ejecting the ink. The ink composition according to any one of items 1 to 26 is a main feature.

A thirtieth aspect is an ink jet recording apparatus, which is characterized mainly by including the ink cartridge according to the twenty-eighth or twenty-ninth aspect.

A thirty-first aspect is an ink jet recording method, which is mainly characterized in that it is carried out by using the ink composition according to any one of claims 1 to 26.

A thirty-second aspect of the present invention is an ink-jet recording method in which an ink-repellent film layer is formed by eutectoid plating on the surface of a nozzle plate of a recording head provided in a recording apparatus main body or an ink cartridge. It records using the ink according to any one of claims 1 to 26.

A thirty-third aspect is an image, which is formed by an ink jet recording method using the ink composition according to any one of the first to twenty-sixth aspects.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The content of the pigment (A) in the ink composition of the present invention varies depending on the type of pigment, the type of solvent or dispersion medium component, and / or required characteristics, and is not particularly limited, but the ink composition The total weight is preferably 5.0 to 15.0 wt%, more preferably 6.0 to 1
It is in the range of 0.0 wt%. Pigment content is 5.0wt
If it is less than%, the coloring of the printed matter may become light, and 1
If it exceeds 5.0 wt%, ejection failure from the printer head may occur. When the content of the pigment is 6.0 wt% or more, it is more preferable from the viewpoint of color developability, and when it is 10.0 wt% or less, it is more preferable from the viewpoint of ejection property.

With respect to the pigment used in the present invention, an inorganic pigment or an organic pigment can be used without any particular limitation. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method or a thermal method can be used. The organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxazine pigments,
A thioindigo pigment, an isoindolinone pigment, a quinofuraron pigment, etc.), a dye chelate (for example, a basic dye type chelate, an acid dye type chelate, etc.), a nitro pigment, a nitroso pigment, and aniline black can be used.

According to a preferred embodiment of the present invention, among these pigments, those having a good affinity for water are preferably used. The particle size of the pigment is preferably 0.05 to 10 μm or less, more preferably 1 μm or less, and most preferably 0.16 μm or less. The addition amount of the pigment as a colorant in the ink is preferably about 5 to 15 wt%, more preferably about 6 to 10 wt%.

Specific examples of the pigment preferably used in the present invention include the following. For black, carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black and channel black, or metal such as copper, iron (CI Pigment Black 11) and titanium oxide And organic pigments such as aniline black (CI Pigment Black 1). Further, for color, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 1
3, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 81, 83 (disazo yellow HR), 95, 97, 98, 100, 101, 104,
408, 109, 110, 117, 120, 138, 1
53, C.I. I. Pigment Orange 5, 13, 16, 1
7, 36, 43, 51, C.I. I. Pigment Red 1,
2, 3, 5, 17, 22 (Brilliant First Scallet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48: 3 ( Permanent Red 2B
(Sr)), 48: 4 (Permanent Red 2B (M
n)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 6
3: 2, 64: 1, 81 (Rhodamine 6G rake), 8
3, 88, 101 (Bengara), 104, 105, 10
6, 108 (Cadmium red), 112, 114, 1
22 (quinacridone magenta), 123, 146, 14
9, 166, 168, 170, 172, 177, 17
8, 179, 185, 190, 193, 209, 21
9, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I.
I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63,
C. I. Pigment Green 1, 4, 7, 8, 10, 1
There are 7, 18, 36 and so on. In addition, it is possible to disperse in water by grafting a pigment (for example, carbon) surface with a resin or the like to make it dispersible in water, or by adding a functional group such as a sulfone group or carboxyl group to the surface of a pigment (for example, carbon). The processed pigment and the like can be used. Alternatively, the pigment may be contained in microcapsules so that the pigment can be dispersed in water.

According to a preferred embodiment of the present invention, the pigment for black ink is preferably added to the ink as a pigment dispersion liquid obtained by dispersing the pigment in an aqueous medium with a dispersant. As a preferable dispersant, a known dispersion liquid used for preparing a conventionally known pigment dispersion liquid can be used. Examples of the dispersion liquid include the following. Polyacrylic acid, polymethacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer,
Styrene-methacrylic acid copolymer, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-
Methacrylic acid-acrylic acid alkyl ester copolymer,
Styrene-α-methylstyrene-acrylic acid copolymer,
Styrene-α-methylstyrene-alkyl acrylate copolymer, styrene-maleic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinylethylene copolymer, Examples thereof include a vinyl acetate-maleic acid ester copolymer, a vinyl acetate-crotonic acid copolymer, a vinyl acetate-acrylic acid copolymer and the like. According to a preferred embodiment of the present invention, these copolymers have a weight average molecular weight of 3,000 to
It is preferably 50,000, more preferably 5,
000-30,000, most preferably 7,000-1
It is 5,000. The addition amount of the dispersant may be appropriately added as long as the pigment is stably dispersed and the other effects of the present invention are not lost. The dispersant is preferably in the range of 1: 0.06 to 1: 3, more preferably 1: 0.125 to 1: 3.
Is the range.

The pigment used as the colorant is contained in an amount of 5 to 15 wt% with respect to the total weight of the recording ink, and is 0.05 to 0.1.
Particles having a particle size of 6 μm or less, dispersed in water with a dispersant, and having a molecular weight of 5,000 to 10
It is a polymer dispersant of 10,000. When a pyrrolidone derivative, particularly 2-pyrrolidone, is used as at least one kind of water-soluble organic solvent, image quality is improved.

The pH of the ink composition of the present invention is 7.0.
The viscosity of a 10 wt% aqueous solution is 5 mPa · s or less (20
C.) ultra low viscosity alginic acid and / or alginate (B).

The alginic acid added here is completely different from conventional alginic acid in terms of molecular weight and viscosity. That is, the conventional alginic acid has a molecular weight of tens of thousands to hundreds of thousands, and the amount added to the ink is 0.02 to a maximum of 0.5 wt%. However, the alginic acid in the present invention is an ultra-low viscosity alginic acid having a molecular weight of several thousand to tens of thousands, a pH of 7.0, and a viscosity of a 10 wt% aqueous solution of 5 mPa · s or less (20 ° C.), and the addition amount to the ink is 5. Even 0 wt% is sufficiently dissolved. The addition amount is preferably 0.1 to 3.0
wt%, and more preferably 0.5 to 2.0 wt%. In the present invention, since a large amount of alginic acid can be added to the ink, the effect of alginic acid could be exerted more remarkably than ever before. The effect of alginic acid will be described below.

In general, alginic acid or alginate can easily react with a polyvalent metal cation other than magnesium (eg, calcium or aluminum) in an aqueous solution containing the same to cause gelation and thicken the aqueous solution. Are known. According to the investigation by the present inventors, general plain paper contains polyvalent metal cations (eg, calcium or aluminum) in addition to monovalent cations (eg, sodium). Has been confirmed. Therefore, when the aqueous ink composition of the present invention is discharged onto plain paper, the polyvalent metal cations on the plain paper are eluted by the ink composition, and the gelling reaction of alginic acid or alginate is promoted. The ink composition thickens due to the rapid gelation, and the spread of plain paper in the plane direction and the permeation in the vertical direction are suppressed. In this way, feathering and bleeding can be prevented or reduced on plain paper, the dot shape can be sharpened, and it can have a favorable effect on high color development. That is, phenomena such as expansion (spreading) and penetration on the paper surface are generally controlled by a penetrant, but can be controlled by the addition of alginic acid or alginate in the ink composition of the present invention. It is also possible to achieve an improvement in print quality such as.

As the ultra-low viscosity alginic acid or alginate (B), for example, an alkali metal salt (eg sodium salt or potassium salt), ammonium salt or substituted ammonium salt of alginic acid having a molecular weight of several thousand to tens of thousands is used. be able to. Substituted ammonium salts are, for example,
Quaternary ammonium mono- or di-substituted, especially tri-substituted with one type of a lower alkyl group having 1 to 4 carbon atoms (in particular, a methyl group or an ethyl group) or two or more types of the same or different lower alkyl groups. It is salt. Further, it is also preferable to use it together with an alkanolamine. Alkanolamines include triethanolamine and the like. Further, it is also preferable to combine it with a quaternary amine substituted with at least two amino alcohols. Examples of this compound include 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol. , Structural formula (1), structural formula (2), structural formula (3), and the like.

Alginic acid in the ink composition is present in the form of coexistence with alkanolamine or quaternary ammonium substituted with at least one or more hydroxyl groups or aminoalcohol rather than alkali metal salt. It is preferable because the solubility is improved, the thermal stability of alginic acid is improved, the stability that the head member and the liquid chamber member are not corroded (particularly in the case of the silicon liquid chamber) is improved, and the stability of the ink composition is improved. Specifically, Aldrich's reagent, Manucol DMF (M / G ratio 1.3) and Manugel GMD (M / G ratio 0.7) manufactured by Dainippon Pharmaceutical Co., Ltd., Duck Algin [Kibun Food Chemifa Corporation] Registered trademark of] and the like can be used. The content of alginic acid or alginate (B) varies depending on the molecular weight of the alginate used and is not particularly limited, but is preferably 0.1 to 3.0 wt% with respect to the total weight of the ink composition, More preferably, it is in the range of 0.5 to 2.0 wt%. If the content of alginic acid or alginate is less than 0.1 wt%, the degree of gelation may be weakened, and if it exceeds 3.0 wt%, the viscosity may increase to the extent that ink cannot be ejected. . When the content of alginic acid or alginate is 0.5 wt% or more, it is more preferable in that gelation is promoted and bleeding is prevented, and 2.0 wt%
The following is more preferable from the viewpoint of ink viscosity (that is, ejection stability).

The present inventors have further investigated the mechanism of gelation by the alginic acid or alginate (B),
Focusing on the ratio of D-mannuronic acid [M] and L-guluronic acid [G] constituting alginic acid (D-mannuronic acid / L-guluronic acid) [hereinafter, sometimes referred to as M / G ratio], As a result of evaluation using alginates having various M / G ratios, there is an M / G ratio range in which color bleeding and feathering (monochromatic ink bleeding along fibers of paper) are more effectively suppressed. Found.

That is, in the ink composition of the present invention, the alginic acid or alginate (B) is M
/ G ratio is preferably 0.05 to 0.8 and 1.5 to 2.
5, more preferably 0.1 to 0.7 and 1.6 to 2.0
The use of alginate in the range of 10 to 50% can prevent the ink composition from penetrating and reduce the fluidity of the ink composition on the paper, thus reducing feathering and color bleeding while improving the coloring property. It is possible to solve the contradictory problem of causing them at the same time. This tendency is 0.05
Although it is remarkable in the range of 0.8 to 0.8, it can be said that the range of 1.5 to 2.5 in which the M ratio is large is excellent from the viewpoint of image quality and storability in consideration of the storability in consideration of heat resistance. Numerical values in this range are in the range where both characteristics of image quality and storability are not compatible.

The M / G ratio of alginate can be measured by acid hydrolysis. Moreover, the alginate having a specific M / G ratio can be selected according to the type of seaweed to be extracted.

The alginic acid or alginate (B) contained in the ink composition of the present invention brings about the excellent effect as described above, while the water content of the ink composition evaporates near the nozzle of the recording head. It was also found that the alginate rapidly increases the viscosity of the ink composition and further solidifies the ink composition, which causes ejection failure of the ink composition from the nozzles and clogging of the nozzles. In the ink composition of the present invention, this drawback is caused by the liquid wetting agent (C).
Can be eliminated by the addition of.

The liquid wetting agent (C) is a wetting agent which is liquid at room temperature, and particularly a water-soluble organic solvent having a high boiling point and low volatility (for example, a water-soluble organic solvent having a boiling point of 200 ° C. or higher) is used. be able to. As the water-soluble organic solvent, for example,
Polyhydric alcohols, particularly divalent to 5 having 2 to 10 carbon atoms
Hydroxyl alcohols; nitrogen-containing hydrocarbon solvents such as formamides, imidazolidinones, pyrrolidones, or amines; sulfur-containing hydrocarbon solvents,
These solvents can be used alone or in combination of two or more.

The ink composition 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, etc. For the purpose of, for example, the following water-soluble organic solvents are used. A plurality of these water-soluble organic solvents may be mixed and used.

Specific examples of preferable water-soluble high-boiling point low-volatile organic solvents are as follows.

Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
Dipropylene glycol, tripropylene glycol,
Tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol,
1,5-pentanediol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol,
Polyhydric alcohols such as 1,2,4-butanetriol, 1,2,3-butanetriol and petriol; ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,
Polyhydric alcohol alkyl ethers such as diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol monophenyl ether,
Polyhydric alcohol aryl ethers such as ethylene glycol monobenzyl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ -Nitrogen-containing heterocyclic compounds such as butyrolactone; formamide, N-methylformamide, N, N
Amides such as dimethylformamide; monoethanolamine, diethanolamine, triethanolamine,
Amines such as monoethylamine, diethylamine and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol; propylene carbonate and ethylene carbonate. Among these organic solvents, especially diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol,
1,5-Pentanediol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred. These have excellent effects on solubility and prevention of defective ejection characteristics due to water evaporation.

The other wetting agent preferably contains sugar. Examples of sugars include monosaccharides, disaccharides,
Examples include oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose and the like. Be done. Here, the term "polysaccharide" means a sugar in a broad sense, and is meant to include substances widely existing in nature such as α-cyclodextrin and cellulose. Examples of derivatives of these sugars include reducing sugars of the above-mentioned sugars (for example, sugar alcohol (general formula HOCH ₂ (CHOH) nCH ₂ OH).
(Here, n represents an integer of 2 to 5). ),
Examples thereof include oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thioacids, and the like. Sugar alcohol is particularly preferable, and specific examples thereof include maltitol, sorbit and the like. The content of these sugars is 0.1% of the ink composition.
The range of -40 wt%, preferably 0.5-30 wt% is suitable.

The ratio of the pigment to the wetting agent has a great influence on the stability of ink ejection from the head. When the solid content of the pigment is high but the blending amount of the wetting agent is small, the pigment is dried on the nozzle plate to cause ejection failure. The wetting agent content is 5-4
On the other hand, the pigment concentration is preferably 5 to 15 wt%, more preferably 6 to 10 wt%, so that the ratio of both the wetting agent and the pigment solid content is 0.3 to 8.0.
However, it is more preferably 2.0 to 6.0, and most preferably 3.0 to 5.0. Inks in this range are very good in drying property, storage test and reliability test.

The present inventors have found that the liquid wetting agent (C) component contains at least glycerin, and the glycerin accounts for 7 wt% of the entire ink composition of the present invention.
When it is contained in the above amount, the color bleeding of the mixed color on the recording medium is reduced or eliminated, and when the content is satisfied, the recorded image on the plain paper becomes high in color development and the print quality is sharp. It is possible to obtain an ink composition for inkjet recording that is clear and does not cause head nozzle clogging. The upper limit of the glycerin content is not particularly limited, but is preferably 15 wt% or less from the viewpoint of preventing ejection failure due to thickening.

Liquid wetting agent (C) other than the above glycerin
The content of is different depending on the type of liquid wetting agent used, the content of glycerin and the like, and is not particularly limited, but is preferably 30 wt% based on the total weight of the ink composition.
% Or less, more preferably 15 to 25 wt%. Therefore, the content of the liquid wetting agent (C) including the glycerin varies depending on the type of the liquid wetting agent used, the content of glycerin, and the like, and is not particularly limited, but is based on the total weight of the ink composition. On the other hand, preferably 5
-40 wt%, more preferably 15-30 wt%. If the content of the wetting agent (C) including glycerin is less than 5 wt%, clogging may occur.
If it exceeds 40 wt%, ejection failure due to thickening may occur.

Further, it is preferable to contain both of the alginic acid or alginate (B) and glycerin in an amount such that the weight ratio thereof is 1:10 to 1:50, because the clogging recovery property is further improved. If the weight ratio is less than 1:10, the effect of clogging recovery may not be sufficient, and if it exceeds 1:50, the ink viscosity may be too high to be practical.

In the ink composition of the present invention, the solid wetting agent (G) which is solid at room temperature (particularly in powder or crystalline form) is used in combination with alginic acid or alginate (B) to suppress feathering and color bleeding. A synergistic effect can be obtained in terms of high color development. That is, the feathering, the suppression of color bleeding and the high color development obtained by containing the alginic acid or the alginate (B) are further improved by using the solid wetting agent (G) together. This mechanism of action is considered to be because the solid wetting agent (F) remains on the recording medium (for example, plain paper for printing) to prevent the pigment (A) from penetrating into the recording medium.

As the solid wetting agent (G), a compound having high hygroscopicity, being easily soluble in an aqueous ink composition or water, and capable of imparting wettability to an ink composition, for example, urea; cyclodextrin, For example, hydroxypropyl-β-cyclodextrin; trimethylol-substituted lower alkane compound having 2 to 4 carbon atoms, such as trimethylolethane or trimethylolpropane; 5 to 7-membered lactam compound, such as caprolactam Monosaccharides or polysaccharides such as sugar and fructose can be used.
The content of the solid wetting agent (G) is the above-mentioned liquid wetting agent (C).
It depends on the type and content of the ink composition and is not particularly limited, but is preferably 3 with respect to the total weight of the ink composition.
It is 0 wt% or less, and more preferably 1.0 to 20 wt%. When the content is less than 1.0 wt%, the suppression of feathering and color bleeding and the high coloring effect may be insufficient, and when it exceeds 30 wt%, ejection failure may occur due to thickening. The content of the solid wetting agent (G) is
The total amount of the liquid wetting agent (C) containing glycerin is preferably 40 wt% or less, more preferably 1% by weight of the ink composition.
It is 5 to 30 wt%. If the total amount of the liquid wetting agent (C) containing glycerin exceeds 40 wt%, ejection failure may occur.

The anionic or nonionic surfactant is not particularly limited, but examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt and polyoxyethylene alkyl ether sulfate. Salt etc. are mentioned. As the nonionic surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc. Can be mentioned. Acetylene glycol-based surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-
4-octyne-3,6-diol, 3,5-dimethyl-
An acetylene glycol-based compound such as 1-hexyn-3-ol (for example, Surfynol 104, 82, 465, 485 or TG manufactured by Air Products Inc. (USA)) can be used, but Surfynol 465, 104 is particularly preferable.
And TG show good print quality. The surfactants may be used alone or in admixture of two or more.

The surface tension in the present invention determines the permeability to paper.
It is an index to show, especially when the surface is formed and the time is shorter than 1 second.
Static showing the dynamic surface tension between
Different from surface tension. As a measuring method, JP-A-63-31
No. 1 second or less by the conventionally known method described in Japanese Patent No. 237, etc.
Any method can be used as long as it can measure the effective surface tension.
However, in the present invention, the Wilhelmy type hanging plate type surface covering is used.
It measured using the dynamometer. The value of surface tension is 40 mJ / m^Two
The following is preferable, and 35 mJ / m is more preferable. ^TwoWith
Then, excellent fixability and dryness can be obtained.

The polyol or glycol ether (D) having 8 to 11 carbon atoms used in the present invention is a partially water-soluble polyol having a solubility of 0.1 to less than 4.5 wt% in water at 25 ° C. And / or glycol ether in an amount of 0.1-10.
It was found that the addition of 0 wt% improves the wettability of the ink to the thermal element, and discharge stability and frequency stability can be obtained even with a small addition amount. (1) 2-Ethyl-1,3-hexanediol Solubility: 4.2% (2
(0 ° C.) (2) 2,2,4-trimethyl-1,3-pentanediol solubility: 2.0% (25 ° C.) having a solubility between 0.1 and less than 4.5 wt% in 25 ° C. water. Penetrants have the advantage that they have very high penetrability instead of low solubility. Therefore, 0.1 in water at 25 ° C
By combining a penetrant having a solubility of less than 4.5 wt% with another solvent or another surfactant, it is possible to produce an ink having a very high penetrability.

A resin emulsion is preferably added to the recording ink of the present invention. The resin emulsion means an emulsion in which the continuous phase is water and the dispersed phase is the following resin component. Examples of the resin component of the dispersed phase include acrylic resin, vinyl acetate resin, styrene-butadiene resin, vinyl chloride resin, acrylic-styrene resin, butadiene resin, and styrene resin. According to a preferred embodiment of the present invention, this resin is preferably a polymer having both a hydrophilic portion and a hydrophobic portion. The particle size of these resin components is not particularly limited as long as it forms an emulsion, but is preferably about 150 nm or less, more preferably about 5 to 100 nm. These resin emulsions can be obtained by mixing resin particles with water, optionally with a surfactant. For example, an acrylic resin or styrene-acrylic resin emulsion is prepared by adding (meth) acrylic acid ester or styrene, (meth) acrylic acid ester, and optionally (meth) acrylic acid ester, and a surfactant to water. It can be obtained by mixing. The mixing ratio of the resin component and the surfactant is usually 1
It is preferably about 0: 1 to 5: 1. If the amount of the surfactant used is less than the above range, it becomes difficult to form an emulsion, and if it exceeds the above range, the water resistance of the ink tends to decrease and the penetrability tends to deteriorate, such being undesirable. The ratio of the resin as the dispersed phase component of the emulsion to water is 60 to 400 parts by weight of water based on 100 parts by weight of the resin.
Weight parts, preferably in the range 100 to 200, are suitable. Examples of commercially available resin emulsions include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink and Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink and Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion,
Saiden Chemical Co., Ltd.), and the like. The ink used in the present invention preferably contains a resin emulsion such that the resin component is 0.1 to 40 wt% of the ink, and more preferably 1 to 25 wt%. Resin emulsion has the property of thickening and aggregating,
It has the effect of suppressing the penetration of the coloring component and further promoting the fixing to the recording material. Further, depending on the type of resin emulsion, a film is formed on the recording material, which has the effect of improving the abrasion resistance of the printed matter.

A preferred ink composition according to the present invention is
(A) Pigment 5.0 to 12.0 wt%, more preferably 6.0 to 10.0 wt%; (B) 10 wt% at pH 7.0.
% Alginic acid or alginate having a neutralization viscosity of 5 mPa · s or less (20 ° C.) 0.1 to 3.0 wt%, more preferably 0.5 to 2.0 wt%; (C) Wetting agent (containing glycerin) 5 wt%. Above, more preferably 15 to 30 wt%;
(D) 1.0 to 2.0 wt% of polyol or glycol ether having 8 to 11 carbon atoms; (E) 0.1 to 5.0 wt% of anionic or nonionic surfactant, more preferably 0.5 to 3 0.0 wt%; and (F) the balance water.

The ink composition for ink-jet recording of the present invention contains the above-mentioned components, but in addition, various conventionally known additives such as a water-soluble organic solvent other than the liquid wetting agent (C) and various additives If necessary, a dispersant, a viscosity modifier, and / or a fluorescent whitening agent may be contained. Examples of the viscosity modifier include water-soluble natural or synthetic polymer compounds such as celluloses, polyvinylpyrrolidone, polyvinyl alcohol, and water-soluble resins.
Further, a buffer solution as a pH adjusting agent, an antifungal agent and the like may be contained.

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

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 quaternary phosphonium. Examples thereof include hydroxides, 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. As the rust preventive agent, for example,
Acid sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite,
Examples include pentaerythritol tetranitrate and dicyclohexyl ammonium nitrite.

A water-soluble ultraviolet absorber, a water-soluble infrared absorber and the like can be added depending on the purpose.

Further, a specific resistance adjusting agent, for example, an inorganic salt,
For example, alkali metal halides or ammonium halides (eg lithium chloride, ammonium chloride,
A recording liquid used in an ink jet recording method of a type in which the recording liquid is charged can be prepared by containing (sodium chloride) or the like.

By adjusting the compounding ratio of each of the above components,
Applicable to the inkjet recording method of the type that discharges the recording liquid by the action of thermal energy by adjusting the thermal property values (evaporation heat, boiling point, melting point, specific heat, thermal expansion coefficient, and / or thermal conductivity, etc.) It is also possible to prepare an ink composition containing

The viscosity of the ink composition of the present invention is preferably 20 mPa · s or less, more preferably 15 mP.
It is possible to ensure stable ejection from the head and stable ink supply to the head by adjusting to a · s or less.

The ink composition for ink jet recording of the present invention is prepared by appropriately mixing the above-mentioned respective components in an arbitrary order, dissolving (or dispersing) them, and removing impurities and the like by filtration. be able to. Further, a pigment is appropriately selected, and if necessary, other compounding components are appropriately selected in combination with the selected pigment, and the yellow ink composition, the magenta ink composition, and the cyan ink for color inkjet recording according to the present invention are selected. A composition, a black ink composition, a blue ink composition, a green ink composition, or a red ink composition can be prepared.

The ink jet recording method according to the present invention comprises:
The present invention is not particularly limited as long as one or more ink compositions according to the present invention are used, but particularly in a color inkjet recording method performed using at least two or more color ink compositions, according to the present invention. It is preferable to use an ink composition. That is, using the above-mentioned yellow ink composition, magenta ink composition, and cyan ink composition, and optionally an ink set combining a black ink composition, a red image, a green image, and a blue image are formed, and further three colors are formed. A color ink jet recording method is preferred in which a black image is formed with a black ink composition which is used by superimposing or separately using the ink composition. The present invention also includes a color inkjet recording method in which various images are formed by using a blue ink composition, a green ink composition, and / or a red ink composition in addition to the above-described ink compositions of the respective colors.

Next, a recording liquid cartridge containing the recording liquid of the present invention and an ink jet recording apparatus equipped with the recording liquid cartridge will be described with reference to the drawings. It does not add any limitation. FIG. 1 is a schematic front view of a mechanical portion of a serial type ink jet recording apparatus in which an ink cartridge having a recording liquid storage portion storing the recording liquid of the present invention is mounted. The mechanical section of the inkjet recording apparatus has a main support guide rod 3 and a sub-support guide rod 4 which are laterally bridged between the side plates 1 and 2 on both sides in a substantially horizontal positional relationship. The rod 4 supports the carriage unit 5 slidably in the main scanning direction. The carriage unit 5 includes four heads 6 that eject yellow (Y) ink, magenta (M) ink, cyan (C) ink, and black (Bk) ink, respectively.
Is mounted with its discharge surface (nozzle surface) 6a facing downward, and 4 is mounted above the head 6 of the carriage unit 5.
Four ink cartridges 7y, 7m, which are ink supply members of respective colors for supplying ink to the individual heads 6,
7c and 7k are mounted interchangeably. The carriage unit 5 is connected to a timing belt 11 stretched between a drive pulley (driving timing pulley) 9 and a driven pulley (idler pulley) 10 which are rotated by the main scanning motor 8, and the main scanning motor 8 is connected. By controlling the drive, the carriage 5, that is, the four heads 6 are moved in the main scanning direction. Also, a bottom plate 1 connecting the side plates 1 and 2
Subframes 13 and 14 are erected on the subframe 2, and a conveyance roller 15 for feeding the sheet 16 in a subscanning direction orthogonal to the main scanning direction is rotatably held between the subframes 13 and 14. Then, a sub-scanning motor 17 is arranged on the side of the sub-frame 14, and in order to transmit the rotation of the sub-scanning motor 17 to the conveying roller 15, the gear 18 fixed to the rotating shaft of the sub-scanning motor 17 and the conveying roller 15 are provided. And a gear 19 fixed to the shaft. Further, a reliability maintaining / restoring mechanism (hereinafter referred to as “subsystem”) 21 of the head 6 is arranged between the side plate 1 and the subframe 12.
The subsystem 21 holds four cap means 22 for capping the ejection surface of each head 6 with a holder 23,
The holder 23 is swingably held by the link member 24, and the carriage unit 5 comes into contact with the engaging portion 25 provided on the holder 23 by the movement of the carriage unit 5 in the main scanning direction, whereby the carriage unit 5 moves. Accordingly, the holder 23 is lifted up and the ejection surface 6a of the inkjet head 6 is capped by the cap means 22, and the carriage unit 5 is moved to the printing area side, so that the holder 23 is lifted down as the carriage unit 5 moves. The cap means 22 is separated from the ejection surface 6a of the inkjet head 6. The cap means 22 is connected to the suction pump 27 via the suction tube 26, forms an atmosphere opening port, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. The suction pump 27 discharges the sucked waste liquid to a waste liquid storage tank (not shown) via a drain tube or the like. Further, on the side of the holder 23, a wiper blade 28, which is a wiping means made of an elastic member such as a fibrous member, a foaming member, or rubber for wiping the ejection surface 6a of the inkjet head 6, is attached to a blade arm 29.
The blade arm 29 is pivotally supported so that it can be swung by the rotation of a cam that is rotated by a driving means (not shown).

Next, the ink cartridge 7 will be described with reference to FIGS. Here, FIG. 2 is an external perspective view of the ink cartridge before being loaded in the recording apparatus, and FIG.
FIG. 3 is a front sectional view of an ink cartridge. The ink cartridge 7 has a cartridge body 41 as shown in FIG.
An ink absorber 42, which absorbs ink of a desired color, is housed therein. The cartridge body 41 is formed by adhering or welding an upper lid member 44 to the upper opening of a case 43 having a wide opening at the top, and is made of, for example, a resin molded product. The ink absorber 42 is made of a porous material such as a urethane foam body and absorbs ink after being compressed and inserted into the cartridge body 41. An ink supply port 45 for supplying ink to the recording head 6 is formed at the bottom of the case 43 of the cartridge body 41, and a seal ring 46 is fitted to the inner peripheral surface of the ink supply port 45. Further, the upper lid member 44 is formed with an atmosphere opening port 47. In the cartridge body 41, the case 43 is compressed and deformed by the pressure applied to the wide side wall when the cartridge main body 41 is closed, the ink supply port 45 is closed, the cartridge is handled during loading, transportation, or vacuum packaging. In order to prevent the internal ink from leaking, a cap member 50 is attached. Further, as shown in FIG. 2, the atmosphere opening port 47 is formed by adhering a film-like sealing member 55 having an oxygen permeability of 100 ml / m ² or more to the upper lid member 44 for sealing. The sealing member 55 is sized to seal not only the atmosphere opening port 47 but also a plurality of grooves 48 formed around it. By sealing the atmosphere opening port 47 with the sealing member 55 having an oxygen permeability of 100 ml / m ² or more in this way, the ink cartridge 7 is packaged in a reduced pressure state using a packaging member such as an aluminum laminated film having no air permeability. As a result, the space A generated when the ink is filled or between the ink absorber 42 and the cartridge body 41 (see FIG. 3)
Even when gas is dissolved in the ink due to the atmosphere in the air, the air in the ink is discharged to the space between the packaging member outside the cartridge main body 41 having a high degree of vacuum through the seal member 55, and the ink is released. Improves temper.

Further, FIG. 4 shows an example of the construction of a recording cartridge having a recording liquid storage portion for storing the recording liquid of the present invention and a head portion for discharging recording liquid droplets.
That is, the recording unit 30 is of a serial type, and mainly includes an inkjet head 6, an ink tank 41 that stores the recording liquid supplied to the inkjet head 6, and a lid member that seals the inside of the ink tank 41. The department is composed. A large number of nozzles 32 for ejecting the recording liquid are formed in the inkjet head 6. The recording liquid is guided from an ink tank 41 to a common liquid chamber (not shown) through an ink supply pipe (not shown), and is ejected from a nozzle 32 in response to an electric signal from the recording apparatus main body input from an electrode 31. It Such a type of recording unit has a structure suitable for a type of head that can be manufactured at low cost, that is, a so-called thermal type or bubble type head that uses thermal energy as a driving power source. The recording liquid of the present invention improves the wettability to the thermal element by adding the component (A) in a recording method such as a bubble method or a thermal method. Therefore, ejection stability and frequency stability can be obtained even with a small addition amount. It is highly suitable because it has high safety and high safety.

Here, the serial type ink jet recording apparatus as described above has been described. However, the recording liquid of the present invention has nozzles in an arbitrary arrangement such as a staggered pattern and has the same resolution as a target image or a fraction thereof. It is also possible to apply the present invention to a recording apparatus having a so-called line head, which is integrated in the density of 1 and is arranged over the width of the recording medium. Further, the recording device referred to here is not only an output printer for a PC or digital camera,
It may be a device having a composite function in combination with a fax, a scanner, a telephone or the like.

[0089]

EXAMPLES Next, the present invention will be described in more detail by way of examples.
explain.Surface treatment of pigment Black is manufactured by the furnace method and channel method
Carbon black with primary particles of 15 nm to 40 nm,
Specific surface area by BET adsorption method is 50 ~ 300m ^Two/ G,
DBP oil absorption is 40-150ml / 100g, volatile matter
Those having 0.5 to 10% and pH 2 to 9 are used,
Especially, acidic carbon black with a pH of 6 or less is preferred because of its high concentration.
Good Also, carbon black and sulfur treated with hypochlorous acid
Carbon black and diazonium treated with rufonizing agent
Anion of sulfonic acid, carboxylic acid, etc. by treating with a compound
Carbon black with a dissociative dissociative group is more preferred.
Yes.

As a yellow pigment, C.I. I Pigment Yellow 74, 128, 138
Is preferred. Examples of magenta pigments include quinacridone C.I. I. Pigment Red 122 and 209 are preferable.
Cyan is a phthalocyanine compound such as C.I. I. Pigment Blue 15: 3, aluminum-coordinated phthalocyanine, and metal-free phthalocyanine are preferable. Among these color organic pigments, pigments having a sulfonic acid group or a carboxylic acid group introduced by surface treatment are further excellent in dispersion stability, and those which can obtain dispersion stability without a dispersant can be suitably used as a self-dispersion pigment. . Further, a pigment having a surface-encapsulated pigment, a pigment grafted with a polymer, or the like can also be an ink having excellent dispersion stability and high reliability.

[0091]Production example 1 Carbon black treated with hypochlorous acid 1 Commercially available acidic carbon black with pH 2.5 (Cabot
Company name Monarch 1300) 300 g water 1000
After mixing well to milliliter, sodium hypochlorite (exist
450 g of effective chlorine concentration of 12%) is dropped to 100 to 10
The mixture was stirred at 5 ° C for 8 hours. Sodium hypochlorite is added to this solution.
Add 100 g (effective chlorine concentration 12%) and use a horizontal disperser.
Dispersed for 3 hours. Dilute the resulting slurry 10 times with water
Then, adjust the pH with lithium hydroxide, conductivity 0.2m
Desalination and concentration with an ultrafiltration membrane to S / cm, pigment concentration 15%
Of carbon black dispersion liquid. Coarse due to centrifugation
Exclude particles, then use a 1 micron nylon filter
It was filtered to obtain a carbon black dispersion liquid 1. Micro tiger
Average particle size (D_50%) Is 95n
It was m.

[0092]Production example 2 Carbon black treated with sulfonating agent 2 Commercially available carbon black pigment ("Printer manufactured by Degussa"
Cus # 85 ") 150 g in 400 ml of sulfolane
Mix well, finely disperse with a bead mill, and add 15 g of amide sulfuric acid.
It added and stirred at 140-150 degreeC for 10 hours. Obtained
Put the resulting slurry in 1000 ml of deionized water and
Surface treated carbon broth with a centrifuge at 2000 rpm
Get a rack wet cake. This carbon black
Redisperse the Etcake in 2000 ml of deionized water
Then, adjust the pH with lithium hydroxide and use an ultrafiltration membrane.
Carbon black with demineralized and concentrated pigment concentration of 10 wt%
Dispersed. This one with a 1μm nylon filter
It was filtered to obtain a carbon black liquid 2. Average particle size is 80
was nm.

[0093]Production Example 3 Carbon black dispersion treated with diazo compound 3 230m surface area^Two/ G of DBP oil absorption is 70ml / 1
100g of carbon black of 00g and p-amino-N
-34 g of benzoic acid and 750 g of water are mixed and dispersed, and
16 g of nitric acid was added dropwise and the mixture was stirred at 70 ° C. 5 minutes later, 50
Add a solution of 11 g of sodium nitrite in g of water.
Then, the mixture was further stirred for 1 hour. 10 times the resulting slurry
Dilute and centrifuge to remove coarse particles, adjust pH to diethanol
Adjust to pH 8-9 with amine and desalt with ultrafiltration membrane
Concentrated to make a carbon black dispersion with a pigment concentration of 15%
It was This is a polypropylene 0.5 μm filter
To obtain Carbon Black Dispersion Liquid 3. Average particle size is 9
It was 9 nm.

[0094]Production Example 4 Carbon black dispersion treated with diazo compound 4 About 75 with 2 liters of water and 43 g of sulfanilic acid
230m while stirring the solution at ℃^Two/ G surface area
202g car with 70ml / 100g DBPA
Added to Bon Black. Stir this mixture while stirring
Cool to warm and add 26.2 g concentrated nitric acid. Underwater
A solution of 20.5 g of sodium nitrite was added. 4-
Produce an inner salt of sulfobenzenediazonium hydroxide,
This was reacted with carbon black. Generated foam
The dispersion was stirred until stopped. The resulting slurry
Dilute and adjust the pH with lithium hydroxide to pH 8-9.
Coarse particles are removed by centrifugation and then ultrafiltration is performed.
Carbon black content with 15% pigment concentration after desalting and concentration with a membrane
Dispersed. This product is a polypropylene 1 μm fill
And filtered through a filter to obtain a carbon black dispersion liquid 4. average
The particle size was 95 nm.

[0095]Production Example 5 Surface chemical treated color pigment dispersion (yellow dispersion
1, magenta dispersion 1, cyan dispersion 1) As a yellow pigment, C.I. I. Pigment Yellow 128
Is treated with low temperature plasma to produce a pigment with carboxylic acid groups introduced.
Made Disperse this in ion-exchanged water and
Yellow pigment dispersion with 15% pigment concentration after desalting and concentration with a membrane
This is liquid 1. The average particle size was 70 nm. Similarly Maze
C. as an intermediate pigment. I. Pigment magenta 122
Then, a magenta pigment dispersion liquid 1 having a pigment concentration of 15% was prepared.
It was The average particle size was 60 nm. Similarly for cyan pigment
C. I. Pigment Cyan 15: 3 using
A 15% cyan pigment dispersion liquid 1 was prepared. Average particle size 8
It was 0 nm.

In the present invention, the use of a surfactant can improve the wettability to recording paper. Preferred surfactants include polyoxyethylene alkyl ether acetates, dialkyl sulfosuccinates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene block copolymers, acetylene glycol surfactants. Is mentioned. More specifically, as the anionic surfactant, a polyoxyethylene alkyl ether acetate of the general formula (4) and / or a polyoxyethylene alkyl ether acetate of the general formula (5) having an alkyl chain having a carbon chain of 5 to 7 By using dialkylsulfosuccinic acid, the properties of plain paper are also improved, and the dissolution and dispersion stability of the colorant is selected.

Further, by using lithium ions and quaternary ammonium and quaternary phosphonium represented by the following general formula as counterions of the surfactant of the present invention, the surfactant exhibits excellent dissolution stability. Preferred nonionic surfactants include polyoxyethylene alkylphenyl ether general formula (6) and acetylene glycol surfactant general formula (9). When these are used in combination, the synergistic effect is further enhanced in penetrability, whereby an ink with less color boundary bleeding and less character bleeding can be obtained.

By recording on the so-called plain paper as described above, it is possible to provide a recording system for forming a recorded image of high image quality and high resolution. However, when the pH is 9 or more, the physical properties of the activator of the general formula (5) are likely to change due to decomposition during storage, and therefore when the general formula (5) is used, the pH is preferably 6 to 9.

By setting the pH of the ink to 6 or more, the storage stability of the ink can be obtained, and many copy papers, sticky notes and the like used in the office have a pH of 5 to 6. Ink is ejected onto the recording paper from a fine ejection port of 9 to 60 μm and is ejected at a rate of 5 to 20 m / s as a droplet having a weight of 3 to 50 ng.
It is possible to provide a recording method for forming a high-quality and high-resolution recorded image by recording on so-called plain paper having a Steckigt sizing degree of 3 seconds or more according to the JIS P-8122 test method at -30 g / m ^2. . However, when the pH is 9 or more, the activator of the general formula (5) is apt to undergo physical property change due to decomposition during storage, and therefore, when the general formula (5) is used,
Is preferably 6-9.

The addition amount of the general formulas (4), (5), (6), (7), (8) and (9) which can be used in the present invention is in the range of 0.05 to 10 wt%. It is possible to give desired penetrability to the ink characteristics required by If the amount is 0.05% or less, bleeding occurs at the boundary of the two-color overlapping portion in all cases, and 10w
If it is added in an amount of t% or more, the compound itself tends to precipitate at low temperature, resulting in poor reliability.

Next, the surfactant (4) used in the present invention,
(5) is specifically shown in Table 1 in free acid form.

[0102]

[Chemical 10]

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples. In the following examples, ultra low viscosity alginic acid manufactured by Kibun Food Chemifa Co., Ltd. was used as alginic acid. Their viscosities [neutralizing viscosities of 10 wt% aqueous solutions (20 ° C.)] were 5.0 mPa · s or less. In each example, the following ingredients were mixed to obtain 60
After stirring at 0 ° C. for 2 hours, pressure filtration was performed at a pressure of ² kg / cm ² using a 0.8 μm diameter membrane filter to obtain an ink composition. In addition, the amount (%) of each component described in the examples is based on weight.

[0104]Method for preparing ultra-low viscosity alginic acid aqueous solution Ultra-low viscosity alginic acid is manufactured by Kibun Food Chemifa Co., Ltd.
Ultra low viscosity alginic acid was used. 200 ml beaker
Add 80 g of ion-exchanged water to the mixture and stir with a stirrer.
Then, 20 g of ultra-low viscosity alginic acid was gradually added. at the time
Alginic acid is not fully dissolved at pH of 2.5
Met. Add choline (trimethyl-2-oxy) to this aqueous solution.
Ciethylammonium hydroxide: Structural formula
Add the 20 wt% aqueous solution of (1)) with gradual stirring.
It was With the addition, the color of the aqueous solution turned brown. pH is
When it reached 7.2, the addition was stopped. After this, stir
Was continued for 3 hours, and the pH was measured after 3 hours had elapsed.
Since it was decreased to 5, choline (trimethyl-2
-Oxyethylammonium hydroxide: structure
The pH is adjusted to 7.3 by adding a 20 wt% aqueous solution of formula (1)).
did. When the pH was measured by continuing stirring for another 3 hours
It was 7.2. Add ion-exchanged water to this aqueous solution
Adjust the solid concentration of formic acid to 10.0 wt%
It was In the examples, this alginic acid aqueous solution was used. That
Others, sodium hydroxide, potassium hydroxide, lithium hydroxide
2-amino-2-methyl-1,3-propanedio
2-amino-2-hydroxymethyl-1,3-pro
Pandiol and an compound having the compound represented by the general formula (1)
An aqueous solution of ruginic acid was prepared in the same manner.

[0105]Example 1 Make an ink composition with the following formulation and adjust the pH to 9
Tris (hydroxymethyl) aminomethane / 2-ami
No-2-hydroxymethyl-1,3-propanediol
It was adjusted with a 10% aqueous solution. After that, average pore size 0.8μ
m membrane filter to filter the ink composition
Obtained.   Carbon dispersion 1 8.0%                                   (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.0%   Sodium hydroxide 0.1%   Triethylene glycol 22.5%   Glycerol 7.5%   2-pyrrolidone 5.0%   Specific example (activators of various activator structural formula (10): I-1) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0106]Example 2 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Carbon dispersion 2 8.0%                                   (Carbon black solid content concentration)   Superviscosity alginic acid (solid content concentration) 1.3%   Potassium hydroxide 0.1%   Propylene glycol 20.0%   Glycerol 10.0%   N-methyl-2-pyrrolidone 2.0%   Specific example (Various activator structural formula (10): I-2) activator 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0107]Example 3 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Carbon dispersion 3 8.0%                                   (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 0.5%   Lithium hydroxide 0.1%   Dipropylene glycol 20.0%   Glycerol 10.0%   N-hydroxyethyl-2-pyrrolidone 5.0%   Specific example (Various activator structural formula (10): I-3) activator 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0108]Example 4 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Carbon dispersion 4 8.0%                                   (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.5%   Lithium hydroxide 0.1%   1,3-butanediol 22.5%   Glycerol 7.5%   2-pyrrolidone 5.0%   Specific example (activators of various activators structural formula (10): I-4) 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0109]Example 5 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Emulsion coating type carbon black dispersion (Kao) 8.0%                                       (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.1%   Triethanolamine 0.1%   2,3-butanediol 22.5%   Glycerol 7.5%   N-methyl-2-pyrrolidone 3.0%   2.0% of an activator of a specific example (various activator structural formula (10): I-5)   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0110]Example 6 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Self-dispersion type carbon black dispersion (manufactured by Toyo Ink Co., Ltd.) 8.0%                                         (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 2.0%   2-amino-2-methyl-1,3-propanediol 0.1%   Dipropylene glycol 15.0%   Glycerol 15.0%   N-hydroxyethyl-2-pyrrolidone 5.0%   Specific examples (Various activators Structural formula (10): I-6) Activator 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0111]Example 7 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Carboxyl group-added carbon black (Cabot Specialty Chemi Cals, Inc.) dispersion liquid 8.0%                                         (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.6%   2-amino-2-ethyl-1,3-propanediol 0.1%   1,3-propanediol 22.5%   Glycerol 7.5%   2-pyrrolidone 5.0%   Specific example (activators of various activator structural formula (10): II-1) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0112]Example 8 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Sulfonate-added carbon black (Cabot Specialty Chemicals) Z ink Inc.) Dispersion liquid 8.0%                                         (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 0.7%   2-amino-2-hydroxymethyl-1,3-propanediol 0.1%   1,4-butanediol 22.5%   Glycerol 7.5%   N-tyl-2-pyrrolidone 2.0%   Specific example (Various activator structural formula (10): II-2) activator 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0113]Example 9 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Carboxyl group-added carbon black (Orient Chemical Co., Ltd.) dispersion                                                               8.0%                                         (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.0%   Compound of structural formula (1) (trimethyl-2-oxyethylammonium hydro Oxide) 0.1%   1,5-Pentanediol 15.0%   Glycerol 15.0%   N-hydroxyethyl-2-pyrrolidone 2.0%   Specific example (activators of various activators structural formula (10): II-3) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0114]Example 10 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Microcapsule inclusion type carbon black (manufactured by Dainippon Ink and Chemicals, Inc.) dispersion Liquid 8.0%                                       (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content) 1.5%   Compound of structural formula (1) (trimethyl-2-oxyethylammonium hydro Oxide) 0.1%   1,6-hexanediol 22.5%   Glycerol 7.5%   2-pyrrolidone 3.0%   Specific example (Various activator structural formula (10): II-4) activator 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0115]Example 11 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Polymer dispersant dispersion type carbon black (Dainichi Seika Kogyo Co., Ltd.) dispersion                                                           8.0%                                           (Carbon black solid content concentration)   Ultra-low viscosity alginic acid (solid content concentration) 0.8%   The compound of structural formula (2) (trimethyl-2-hydroxyethoxyammonium ha Idrooxide) 0.1%   2-methyl-2,4-pentanediol 22.5%   Glycerol 7.5%   N-methyl-2-pyrrolidone 5.0%   The activator of the general formula (6) (R = C₆, K = 5) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0116]Example 12 The same procedure as in Example 1 was repeated except that the following composition was used, and the pH was adjusted.
Tris (hydroxymethyl) aminomethane / 2-amino
-2-Hydroxymethyl-1,3-propanediol 1
The ink composition was adjusted to 9 with a 0% aqueous solution.   Surfactant dispersion type carbon black (manufactured by Fuji Dye Co., Ltd.) dispersion liquid 8.0%                                       (Carbon black solid content concentration)   Low super-viscosity alginic acid (solid content concentration) 1.7%   Compound of structural formula (3) (trimethyl-2- (2-hydroxyethoxy) ethoxy Ammonium hydroxide) 0.1%   1,2,6-hexanetriol 20.0%   Glycerol 10.0%   N-hydroxyethyl-2-pyrrolidone 5.0%   The activator of the general formula (6) (R = C₆, K = 5) 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0117]Example 13 Tris was prepared in the same manner as in Example 1 except that the following composition was used.
(Hydroxymethyl) aminomethane / 2-amino-2-
Hydroxymethyl-1,3-propanediol 10% water
The pH of the solution was adjusted to 9 to prepare an ink composition.   Carboxyl group-added self-dispersion type carbon black dispersion (Taisei Kako Co., Ltd.)                                                           8.0%                                       (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 2.2%   Compound of structural formula (3) (trimethyl-2- (2-hydroxyethoxy) ethoxy Ammonium hydroxide) 0.1%   Trimethylol propane 15.0%   Glycerol 15.0%   2-pyrrolidone 4.0%   Activator of the general formula (8) (R '= 6, n = 2, m = 3) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0118]Example 14 Tris was prepared in the same manner as in Example 1 except that the following composition was used.
(Hydroxymethyl) aminomethane / 2-amino-2-
Hydroxymethyl-1,3-propanediol 10% water
The pH of the solution was adjusted to 9 to prepare an ink composition.   Polymer dispersant Dispersion type carbon black (manufactured by Mikuni dye company) Dispersion liquid 8.0%                                         (Carbon black solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 0.9%   Compound of structural formula (3) (trimethyl-2- (2-hydroxyethoxy) ethoxy Ammonium hydroxide) compound 0.1%   Trimethylolethane 22.5%   Glycerol 7.5%   2-pyrrolidone 2.0%   Activator of the general formula (9) (mixture of p + q = 15 and p + q = 0) 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0119]Cyan pigment ink Tris was prepared in the same manner as in Example 1 except that the following composition was used.
(Hydroxymethyl) aminomethane / 2-amino-2-
Hydroxymethyl-1,3-propanediol 10% water
The pH of the solution was adjusted to 9 to prepare an ink composition.   Cyan dispersion 1 6.0%                                               (Cyan pigment solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.4%   Trimethyl-2-oxyethyl ammonium hydroxide 0.1%   Urea 22.5%   Glycerol 7.5%   N-hydroxyethyl-2-pyrrolidone 5.0%   ECTD-3NEX (Nikko Chemicals anionic surfactant) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0120]Magenta pigment ink Tris was prepared in the same manner as in Example 1 except that the following composition was used.
(Hydroxymethyl) aminomethane / 2-amino-2-
Hydroxymethyl-1,3-propanediol 10% water
The pH of the solution was adjusted to 9 to prepare an ink composition.   Magenta dispersion 1 6.0%                                             (Magenta pigment solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.4%   Trimethyl-2-oxyethyl ammonium hydroxide 0.1%   1,3-Dimethylimidazolidinone 15.0%   Glycerol 15.0%   2-pyrrolidone 5.0%   ECTD-6NEX (Nikko Chemicals anionic surfactant) 2.0%   2,2,4-trimethyl-1,3-pentanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0121]Yellow pigment ink Tris was prepared in the same manner as in Example 1 except that the following composition was used.
(Hydroxymethyl) aminomethane / 2-amino-2-
Hydroxymethyl-1,3-propanediol 10% water
The pH of the solution was adjusted to 9 to prepare an ink composition.   Yellow dispersion 1 6.0%                                             (Yellow pigment solid content concentration)   Ultra low viscosity alginic acid (solid content concentration) 1.6%   Trimethyl-2-oxyethyl ammonium hydroxide 0.1%   Multitose 20.0%   Glycerol 10.0%   N-methyl-2-pyrrolidone 5.0%   Dispanol TOC (Nonionic surfactant made by NOF Corporation) 2.0%   2-ethyl-1,3-hexanediol 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0122]Comparative Example 1 Make an ink composition with the following formulation and adjust the pH to 9
It was adjusted with a 10% aqueous solution of lithium hydroxide. afterwards,
Perform filtration with a membrane filter with an average pore size of 0.8 μm.
A good ink composition was obtained.   Carboxyl group-added carbon black dispersion   (Cabot Specialty Chemicals, Inc.) 5.0%                                         (Carbon black solid content concentration)   Sodium alginate (NSPLL) 0.1%   Glycerin 15.0%   Diethylene glycol 15.0%   Triethylene glycol monobutyl ether 4.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0123]Comparative example 2 Hydroxylation was conducted in the same manner as in Comparative Example 1 except that the following composition was used.
An ink composition was prepared by adjusting the pH to 9 with lithium.   Polymer dispersant dispersion type carbon black dispersion (manufactured by Dainichiseika Kogyo Co., Ltd.)                                                             5.0%                                         (Carbon black solid content concentration)   Sodium alginate (Manugel GMD) 0.1%   Glycerin 20.0%   Diethylene glycol 10.0%   Triethylene glycol monobutyl ether 4.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0124]Comparative Example 3 Hydroxylation was conducted in the same manner as in Comparative Example 1 except that the following composition was used.
An ink composition was prepared by adjusting the pH to 9 with lithium.   Surfactant-dispersed carbon black dispersion (Fuji Dye Co., Ltd.) 5.0%                                         (Carbon black solid content concentration)   Sodium alginate (Manugel DMF) 0.15%   Glycerin 22.5%   Diethylene glycol 7.5%   Triethylene glycol monobutyl ether 4.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0125]Comparative Example 4 Hydroxylation was carried out in the same manner as in Example 1 except that the following composition was used.
An ink composition was prepared by adjusting the pH to 9 with sodium.   Microcapsule inclusion type carbon black dispersion                     (Manufactured by Dainippon Ink and Chemicals, Inc.) 5.0%                                       (Carbon black solid content concentration)   Sodium alginate (Manugel DMF) 0.08%   Glycerin 15.0%   Urea 15.0%   Surfynol 465 0.6%   Triethylene glycol monobutyl ether 2.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

[0126]Comparative Example 5 Hydroxylation was carried out in the same manner as in Example 1 except that the following composition was used.
An ink composition was prepared by adjusting the pH to 9 with lithium.   Self-dispersion type carbon black dispersion (manufactured by Taisei Kako Co., Ltd.) 5.0%                                       (Carbon black solid content concentration)   Sodium alginate (Manugel DMF) 0.1%   Glycerin 20.0%   Diethylene glycol 10.0%   Urea 2.0%   Surfynol 465 0.5%   Triethylene glycol monobutyl ether 1.0%   Proxel LV (preservative) 0.2%   Deionized water remaining

Table 1 shows pigment concentrations, wetting agent concentrations and ink viscosities of the ink compositions of Examples 1 to 14 and cyan, magenta and yellow pigment inks and Comparative Examples 1 to 5.

[0128]

[Table 1]

Next, the above Examples 1 to 14 and Comparative Examples 1 to 5
The following test was conducted on (1) Image clarity With an inkjet printer EM-900 (manufactured by Seiko Epson Corporation), head drive voltage, frequency,
Printing was performed on each of the following papers while changing the pulse width. With respect to the print pattern, the color pigment inks of yellow, magenta, and cyan were printed at 100% duty, and the black ink filled with the black ink of the present invention printed characters at the same time. The printing conditions were 35 pl for Mj, 20 m / sec for Vj, a frequency of 1 kHz, a recording density of 360 dpi, and one-pass printing. Bubble jet inkjet printer BJC430 manufactured by Canon Inc. and bubble jet inkjet printer hp diskjet815 manufactured by HP.
The ink is packed in the BK cartridge of, and the printing conditions are as follows: Mj is 35 pl, Vj is 20 m / sec, frequency is 1 kHz,
The recording density was 360 dpi, and solid and characters were printed by one-pass printing. Ricoh inkjet printer IPSiO Je
At t300, the drive voltage, frequency, and pulse width of the head were changed, and solid and characters were printed by one-pass printing. After printing, the bleeding at the boundary of the two-color overlapping portion, image bleeding, color tone, and image density were comprehensively examined visually and by a reflection type color spectrophotometric densitometer (manufactured by X-Rite) and judged according to the evaluation standard. did. The printing test paper used is shown below. My paper (manufactured by NBS Ricoh Co., Ltd.) Paper source S / recycled paper (manufactured by NBS Ricoh Co., Ltd.) PB paper (manufactured by Canon Inc.) Multi-ace (manufactured by Fuji Xerox Office Supply Co., Ltd.) Yamayuri paper (manufactured by Honshu Paper Co., Ltd.) Recycled paper) LH paper (manufactured by Fuji Xerox Office Supply Co., Ltd.) Xerox 4024 paper (manufactured by Fuji Xerox Office Supply Co., Ltd.) Neenh Bond paper (manufactured by Kimberly Clark Co., Ltd.) Judgment criteria ⊚: Clear printing without blurring of all papers. B: Some paper (recycled paper) has whisker-like bleeding. Δ: Whisker-like bleeding occurs on all paper. X: Blurring occurs so that the outline of the character is not clear. (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 was placed 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 Using the head of the Ricoh printer IPSiO Jet300, it is checked how long the printing can be resumed even if the printing is suspended without performing capping, cleaning, etc. during printer operation, and how long (seconds) Table 2 shows the results of evaluation of the reliability depending on whether the jetting direction is deviated or the weight of the ejected liquid droplets is changed.

[0130]

[Table 2]

[0131]

As described above, according to the ink composition of claim 1, at least (A) pigment, (B) alginic acid having a pH of 7.0 and a neutralization viscosity of 10 wt% of 5 mPa · s or less (20 ° C.). And / or alginate, (C) wetting agent,
In the ink composition comprising (D) a polyol or glycol ether having 8 to 11 carbon atoms, (E) an anion or nonionic surfactant, and (F) water, Mj is 5 to 3
5 pl, Vj 6-20 m / sec, frequency 1 kHz
As described above, it is possible to obtain a high-quality image comparable to a laser printer on plain paper under the one-pass printing condition with the resolution of 300 dpi or more. (Feathering and color bleed are similar to those of laser, image density: 1.5-1.6 / conventional 1.1-
1.2). Further, since the pigments are aggregated on the paper surface, the strikethrough is remarkably reduced as compared with the conventional case, and the double-sided printing is possible (the strikethrough density: 0.02 to 0.04 / the conventional 0.2 to
0.3).

According to the ink composition of claim 2, the conventional alginic acid has a molecular weight of tens of thousands to hundreds of thousands, and the addition amount to the ink can be added from 0.02 to 0.5 wt% at most. However, alginic acid in the present invention is an ultra-low viscosity alginic acid having a molecular weight of several thousand to tens of thousands, a pH of 7.0 and a viscosity of a 10 wt% aqueous solution of 5 mPa · s or less (20 ° C.), and the addition amount to the ink is Even 5.0 wt% is sufficiently dissolved. The addition amount is preferably 0.1 to 3.0 wt%, more preferably 0.5 to 2.0 wt%. In the present invention, since a large amount of alginic acid can be added to the ink, the effect of alginic acid could be exerted more remarkably than ever before.

According to the ink composition of claim 3, the low-viscosity alginic acid is used in combination with at least one selected from alkali metals, alkanolamines, quaternary ammonium substituted with at least one or more hydroxyl groups, and amino alcohols. This improves the solubility of alginic acid, improves the thermal stability of alginic acid, and does not corrode the head member and the liquid chamber member (especially in the case of the silicon liquid chamber), and the stability of the ink composition is improved. improves.

According to the ink composition of claim 4, since the alkali metals are sodium, potassium and lithium, the solubility of alginic acid is improved, the thermal stability of alginic acid is improved, and the head member and the liquid chamber member are corroded. The stability (especially in the case of a silicon liquid chamber) is provided so that the stability of the ink composition is improved.

According to the ink composition of claim 5, since the alkanolamine is triethanolamine, the solubility of alginic acid is improved, the thermal stability of alginic acid is improved, and the head member and the liquid chamber member are not corroded. Stability (particularly in the case of a silicone liquid chamber) is provided and the stability of the ink composition is improved.

According to the ink composition of claim 6, the amino alcohol is 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 2-amino. -2-hydroxymethyl-1,
The use of 3-propanediol improves the solubility of alginic acid, the thermal stability of alginic acid, and the stability of not corroding the head member and the liquid chamber member (especially in the case of the silicone liquid chamber). The stability of the product is improved.

According to the ink composition of claim 7, since the quaternary ammonium substituted with at least one or more hydroxyl groups has the structural formulas (1), (2) and (3), the solubility of alginic acid is high. And the thermal stability of alginic acid, and the stability of not corroding the head member and the liquid chamber member (particularly in the case of the silicon liquid chamber), and the stability of the ink composition is improved.

According to the ink composition of claim 8, the suppression of color bleeding and feathering (blurring of a single color ink along the fibers of the paper) is further improved, and D-mannuronic acid and L-containing alginic acid are contained. Ratio with guluronic acid (D-
The presence of mannuronic acid / L-guluronic acid) was found. That is, by using alginic acid having an M / G ratio in the range of 0.05 to 0.8, it is possible to suppress the permeation of the ink composition and reduce the fluidity of the ink composition on paper. It is possible to simultaneously solve the contradictory problems of reducing feathering and color bleed while improving the color developability.

According to the ink composition of claim 9, the suppression of color bleeding and feathering (blurring of a single color ink along the fibers of paper) is further improved, and D-mannuronic acid and L-containing alginic acid are contained. Ratio with guluronic acid (D-
The presence of mannuronic acid / L-guluronic acid) was found. That is, by using alginic acid having an M / G ratio in the range of 1.5 to 2.5, the permeation of the ink composition can be suppressed and the fluidity of the ink composition on paper can be reduced. It is possible to simultaneously solve the contradictory problems of reducing feathering and color bleed while improving the color developability. This tendency is remarkable in the range of 0.05 to 0.8. Considering further the storage stability considering heat resistance, the range of 1.5 to 2.5 in which the M ratio is large is from the viewpoint of image quality and storage stability. Can be said to be excellent. Numerical values in this range are in the range where both characteristics of image quality and storability are not compatible.

According to the ink composition of claim 10, the weight ratio of alginic acid or alginate to the wetting agent is 1:10.
It is preferable to mix both in an amount of 1:50, because the recovery from clogging is further improved. If the weight ratio is less than 1:10, a sufficient effect on clogging recovery may not be obtained, and if it exceeds 1:50, the ink viscosity may be too high to be practical.

According to the ink composition of claim 11, the polyol or glycol ether is 2-ethyl-1,
3-hexanediol or 2,2,4-trimethyl-
Since it is 1,3-pentanediol, the wettability of the ink to the thermal element is improved, and ejection stability and frequency stability can be obtained even with a small addition amount.

According to the ink compositions of the twelfth and thirteenth aspects, the anionic or nonionic surfactant is one of the general formulas (4), (5), (6), (7), (8) and (9). The surface tension of the ink is 40 dyn / cm or less and the pigment concentration is 6 wt% due to the interaction between the polyol having 8 or more and 11 or less carbon atoms and the surfactants (4) to (9). Even if it has a high viscosity of not less than 0.1% and not less than 8.0 cps, it can be quickly fixed on most recording materials and has sufficient marker resistance. In addition, the wettability of the head member is improved, the bubble discharge property of the ink composition is improved, the frequency response is improved, and the ejection stability is significantly improved.

According to the ink compositions of claims 14 and 15, the coloring material can be left on the recording medium by adding a solid (particularly powder or crystalline) solid wetting agent at room temperature, and image density can be improved. It is possible to improve, prevent strike-through, and reduce feathering. Furthermore, when used in combination with alginic acid, the solid wetting agent remains on the recording medium to impede the penetration of the coloring material into the recording medium, and the high color developability is further improved.

According to the ink composition of claim 16, these wetting agents are preferable from the viewpoints of moisturizing property, ink viscosity, ejection stability, frequency stability, and reduction of feathering and color bleed, and a well-balanced ink. A composition is obtained.

According to the ink compositions of claims 17 and 18, since the wetting agent is a combination of glycerin and any one of the wetting agents other than the glycerin, a high viscosity glycerin and a low viscosity suitable are used. A well-balanced wetting agent is obtained by mixing the wetting agent. In addition to viscosity, a well-balanced ink composition can be obtained from the viewpoints of moisture retention, ejection stability, frequency stability, feathering and reduction of color bleed.

According to the ink composition of the nineteenth aspect, since the preferable pigment concentration is 5 to 15 wt%, the viscosity of the ink becomes high, the pigment easily aggregates on the paper surface, and the image density (OD) is improved. Feathering is almost gone with it.

According to the ink compositions of claims 20 to 22,
Since the pigment is a self-dispersion pigment and further has a carboxyl group, a sulfone group, a carbonyl group, or a hydroxyl group on the surface, good dispersion in water can be achieved.

According to the ink composition of the twenty-third aspect, since the average particle size of the self-dispersion pigment is 0.16 μm or less, the ejection stability and the clogging property of the ink are remarkably improved.

According to the ink composition of the twenty-fourth aspect, since the weight ratio of the wetting agent to the pigment is 0.3 to 8.0, the pigment is stably dispersed, and the drying property, storage test and reliability test are carried out. Is very good.

According to the ink composition of claim 25,
By containing at least one selected from pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and ε-caprolactam, it is possible to improve the filling of the black pigment ink on the recording medium and the coloring property. .

According to the ink composition of claim 26, since the viscosity of the ink is 8 to 20 cps (25 ° C.),
The printing quality is greatly improved. In such a high-viscosity ink, the water content in the ink is about 50% or less, and the evaporation rate of water when the ink droplets land on the paper surface becomes 2.0 to 3.0 times higher. Therefore, the high-concentration pigment aggregates on the paper surface at a high speed, and bleeding (feathering) is almost eliminated.

According to the ink composition set for color ink jet recording of claim 27, color coloring property is improved, color bleeding is reduced, color unevenness in color overprinting is improved,
In particular, it brings about a reduction in color misregistration of RGB coloring due to a difference in printing order.

According to the ink cartridges of the twenty-eighth and twenty-ninth aspects, it is possible to obtain a recording liquid cartridge containing an ink having a high penetrating property and capable of high reliability, safety and excellent image characteristics.

According to the ink jet recording apparatus of the thirtieth aspect, since the ink jet recording is carried out using the ink of the present invention, the image quality such as feathering, print density reduction, color bleeding and the like, which have been conventionally problematic, can be obtained. Can obtain improved high-quality image

According to the ink-jet recording method of the thirty-first aspect, since ink-jet recording is carried out using the ink of the present invention, improvement in image quality such as feathering, print density reduction, color bleeding and the like, which have been conventionally problematic, is achieved. It is possible to obtain a high quality image.

According to the ink jet recording method of the thirty-second aspect, recording is performed using the ink of the present invention and an ink jet recording apparatus in which an ink repellent film layer is formed on the surface of the nozzle plate of the recording head by eutectoid plating. As a result, problems such as changes in ink droplet size and ejection failure can be prevented, and high-quality image quality without the above-described feathering, print density reduction, color bleeding, and the like can be obtained.

An image formed by the ink jet recording method according to claim 33 has feathering and a decrease in print density.
High quality image with no color bleeding.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an inkjet device with a cartridge that contains an ink of the present invention.

FIG. 2 is an external perspective view of an ink cartridge before being loaded in the recording apparatus of the present invention.

FIG. 3 is a front sectional view of an ink cartridge containing the ink of the present invention.

FIG. 4 is an external view of a recording unit integrated with a recording head using ink of the present invention.

[Explanation of symbols]

3 Main support guide rod 4 Support guide rod 5 Carriage unit 6 heads 7y, 7m, 7c, 7k ink cartridge 9 Drive pulley 10 Driven pulley 11 Timing belt 15 Conveyor roller 16 sheets 21 subsystem 22 Cap means 23 Holder 24 Link member 25 Engagement part 26 Suction tube 27 Suction pump 30 recording units 31 electrodes 32 nozzles 41 Cartridge body 42 ink absorber 43 cases 44 Upper lid member 46 seal ring 45 ink supply 47 Atmosphere opening 55 Film seal member

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2C056 EA05 FC01 KC01                 2H086 BA55 BA59 BA60 BA61 BA62                 4J039 AB01 AE07 BA14 BC07 BC09                       BC13 BC19 BC33 BC54 BE01                       BE02 BE15 BE22 EA42 EA47

Claims (33)

[Claims] 1. At least (A) pigment, (B) pH 7.
At 0, the viscosity of a 10 wt% aqueous solution at 20 ° C is 5 mPa · s.
An ink composition comprising the following alginic acid and / or alginate, (C) a wetting agent, (D) a polyol or glycol ether having 8 to 11 carbon atoms, and (E) an anion or nonionic surfactant. object. 2. The alginic acid or alginate is added in an amount of 0.
The ink composition according to claim 1, wherein the ink composition contains 1 to 3.0 wt%. 3. An alginic acid and at least one selected from an alkali metal hydroxide, an alkanolamine, a quaternary ammonium substituted with at least one or more hydroxyl groups, and an aminoalcohol. The ink composition according to 1 or 2. 4. The ink composition according to any one of claims 1 to 3, wherein the alkali metal hydroxide according to claim 3 is sodium hydroxide, potassium hydroxide or lithium hydroxide. 5. The ink composition according to any one of claims 1 to 3, wherein the alkanolamine according to claim 3 is triethanolamine. 6. The amino alcohol according to claim 3 is 2
-Amino-2-methyl-1,3-propanediol, 2
The ink according to any one of claims 1 to 3, which is -amino-2-ethyl-1,3-propanediol or 2-amino-2-hydroxymethyl-1,3-propanediol. Composition. 7. The quaternary ammonium substituted with at least one hydroxyl group has the following structural formulas (1) and (2):
The ink composition according to any one of claims 1 to 3, which is the compound of (3). Embedded image [(CH ₃ ) ₃ N—CH ₂ CH ₂ OH] ⁺ OH ⁻ (1) Trimethyl-2-hydroxyethylammonium hydroxide embedded image [(CH ₃ ) ₃ N—CH ₂ CH ₂ O —CH ₂ CH ₂ OH] ⁺ OH ⁻ (2) Trimethyl-2-hydroxyethoxyammonium hydroxide embedded image [(CH ₃ ) ₃ N— (CH ₂ CH ₂ O) ₂ —CH ₂ CH ₂ OH] ⁺ OH ^- (3) trimethyl-2- (2-hydroxyethoxy) ethoxy ammonium hydroxide 8. As the alginic acid (B), the ratio of D-mannuronic acid and L-guluronic acid constituting alginic acid (D-mannuronic acid / L-guluronic acid) is 0.05 to.
The ink composition according to any one of claims 1 to 7, wherein alginic acid in the range of 0.8 is used. 9. The alginic acid (B) has a ratio of D-mannuronic acid and L-guluronic acid constituting alginic acid (D-mannuronic acid / L-guluronic acid) of 1.5 to.
The ink composition according to claim 1, wherein alginic acid in the range of 2.5 is used. 10. The weight ratio of the alginic acid or alginate (B) to the wetting agent (C) is 1:10 to 1:50.
The ink composition according to any one of claims 1 to 9, wherein 11. The polyol or glycol ether is 2-ethyl-1,3-hexanediol or 2,
The ink composition according to any one of claims 1 to 10, which is 2,4-trimethyl-1,3-pentanediol. 12. The anionic or nonionic surfactant is represented by the following general formulas (4), (5), (6), (7),
The ink composition according to any one of claims 1 to 11, which is at least one selected from the surfactants (8) and (9). [Chemical 4] [Chemical 5] [Chemical 6] [Chemical 7] [Chemical 8] [Chemical 9] 13. The ink composition according to claim 1, which contains 0.1 to 5.0 wt% of the anionic or nonionic surfactant. 14. The ink composition according to claim 1, wherein the wetting agent is a solid wetting agent. 15. The ink composition according to claim 14, wherein the solid wetting agent (G) is included in an amount of 0.5 to 30 wt% of the ink composition. 16. The humectant (G) is glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, or 2. , 3-butanediol, 1,4-butanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-
Characterized by comprising at least one selected from 2,4-pentanediol, 1,2,4-butanetriol, 1,2,6-hexanetriol, trimethylolpropane, trimethylolethane, thiodiglycol and pentaerythritol. The ink composition according to any one of claims 1 to 15. 17. The ink composition according to claim 1, wherein the wetting agent is a wetting agent obtained by mixing glycerin and a wetting agent other than glycerin. 18. The ink composition according to claim 1, which contains the wetting agent in an amount of 5 to 40 wt%. 19. The ink composition according to claim 1, wherein the pigment concentration is 5 to 15 wt%. 20. The ink composition according to any one of claims 1 to 19, wherein the pigment is a self-dispersion pigment. 21. The ink composition according to claim 20, wherein the self-dispersion pigment has a carboxyl group, a sulfone group, a carbonyl group or a hydroxyl group on the surface. 22. At least one kind of hydrophilic group is contained on the surface of the self-dispersion pigment by any of diazo compound treatment, oxidation treatment, hypochlorous acid treatment, sulfonating agent treatment and humic acid treatment. The ink composition according to claim 20 or 21. 23. The average particle size of the self-dispersion pigment is 0.16.
The ink composition according to any one of claims 20 to 22, which has a thickness of not more than μm. 24. A wetting agent to pigment weight ratio of 0.3 to 8.
The ink composition according to any one of claims 1 to 23, which is 0. 25. At least one selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone and ε-caprolactam is contained. The ink composition according to one item. 26. The viscosity of the ink is 8 to 20 mPa · s.
(25 ° C.) 26. The ink composition according to claim 1, wherein the ink composition is (25 ° C.). 27. A color ink jet recording ink composition set comprising two or more color ink compositions,
3. At least one of the ink compositions is defined in claim 1.
7. The ink composition set for color inkjet recording, which is the ink composition according to any one of 6 above. 28. An ink cartridge containing the ink composition according to any one of claims 1 to 26. 29. An ink according to any one of claims 1 to 26, wherein the ink is an ink cartridge for inkjet recording provided with an ink containing portion containing ink and a recording head portion for ejecting the ink. An ink cartridge for inkjet recording, which is a composition. 30. An ink jet recording apparatus comprising the ink cartridge according to claim 28 or 29. 31. An ink jet recording method, which comprises using the ink composition according to any one of claims 1 to 26. 32. An ink jet recording apparatus according to any one of claims 1 to 26, wherein an ink repellent film layer is formed by eutectoid plating on a surface of a nozzle plate of a recording head provided in a recording apparatus main body or an ink cartridge. An ink jet recording method comprising recording using the ink described. 33. An image formed by an inkjet recording method using the ink composition according to any one of claims 1 to 26.