JP2003268275A - Ink set for ink-jet recording and ink-jet recording method, and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink set for ink-jet recording which, when printed, can give so excellent image qualities that stains are hardly perceptible, exhibits excellent image-fixing properties and hardly causes uneven gloss, an ink-jet recording method and a recorded matter obtained by the same. <P>SOLUTION: The ink set for ink-jet recording comprises at least one 'thick pigment ink comprising a pigment, a resin dispersant and water' and at least one 'thin pigment ink comprising a pigment, a resin dispersant and water, and having a pigment density not higher than half of the pigment density in the thick pigment ink', and is composed so that the acid value of the resin dispersant in the thick pigment ink is lower than that of the resin dispersant in the thin pigment ink. The ink-jet recording method comprises using the same. The recorded matter is obtained by the method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink set for ink jet recording, an ink jet recording method using the ink set, and a recorded matter obtained by the ink set. In particular, stains are hardly recognized when printed. The present invention relates to an ink set for inkjet recording capable of obtaining excellent image quality, an inkjet recording method using the same, and a recorded matter obtained by the method.

[0002]

2. Description of the Related Art Ink jet recording is a method in which ink is ejected as small droplets from fine nozzles to record characters or figures on the surface of a recording medium. As an inkjet recording method, an electrostrictive element is used to convert an electrical signal into a mechanical signal, and ink stored in the nozzle head portion is intermittently ejected to record characters or symbols on the surface of a recording medium, or a nozzle head portion. There is a method of recording characters and symbols on the surface of the recording medium by rapidly heating a portion of the ink that is very close to the ejection portion to generate bubbles, which is intermittently ejected due to the volume expansion of the bubbles. It has been put to practical use.

As a method of supplying ink in ink jet recording, a method using an ink set formed by combining inks having a plurality of different colors is known. According to such an ink set, the type and the ejection amount of each ink ejected from the ink set are selected at any time according to the signal based on the image information, so that a color image such as a photographic image can be rendered in high quality. There is an advantage that it can be easily obtained with. As an ink set, one having a plurality of inks having different colorant concentrations in the same hue (also referred to as a dark and light ink set) is known, and the colorant concentration is set to an area to be printed with a predetermined print density. Ink of ink (also called dark ink) set to a high value
By actively increasing the ink Duty of the ink (also referred to as a light ink) in which the colorant concentration is set lower than the duty (the amount of ejected ink per unit area),
The graininess of the obtained image can be reduced.

However, when an image (particularly, a photographic image) that requires a high ink duty is printed, the paper (particularly plain paper) absorbs the moisture of the ink and stretches, resulting in an uneven shape. However, there is a possibility that the paper is easily bent and the deformed paper comes into contact with the head of the printer, so that desired printing cannot be performed. Therefore, the printer is usually provided with rollers that can hold the paper in a predetermined position to prevent contact between the paper and the head.

As the ink contained in the ink set used for such a printer, those prepared by dissolving various water-soluble dyes in an aqueous medium are generally used, but recently, pigments have been dispersed by a dispersant. Inks dispersed in an aqueous medium are also provided. This is because the ink using a pigment (hereinafter, also referred to as a pigment ink) has a feature that it is excellent in weather resistance (water resistance, light resistance, etc.) as compared with an ink using a water-soluble dye. Here, since the pigment is generally insoluble in water, when the pigment is used as a colorant for the water-based ink composition, after the pigment is mixed with a dispersant and dispersed stably in water, It is prepared as an ink composition.

[0006]

However, even when the pigment ink prepared in such a manner is used, the ink does not become clear particularly when plain paper is used or when an image having a large amount of ink duty such as a photographic image is formed. Hard to penetrate into paper. Therefore, in such a case, in the roller described above,
There is a problem that the ink that has not penetrated into the paper easily adheres, and the roller to which the ink adheres easily stains the image (hereinafter, this phenomenon is also referred to as “ink transfer”). When printing is performed using the dark and light ink set described above in order to reduce the graininess of the image, the ink duty of the light ink is set to be high, and the amount of ink that is ejected onto the paper tends to increase. It is difficult for the ink to permeate the recording paper, and the ink that has not permeated causes ink transfer, making it easy to visually recognize stains on the image. In particular, when an ink set in which the pigment concentration of the dark and light ink is set to be high in order to obtain an image with high color developability, stains on the image are easily noticeable. Further, there has been a problem that the increase in the printing speed that has been recently demanded causes ink to easily adhere to the roller before it penetrates into the paper, thus contributing to an increase in ink transfer.

Further, when the pigment ink is used, although the weather resistance is excellent as described above, the fixing property of the image on the paper is insufficient, or the unevenness due to the difference in the glossiness between the regions having different ink duties is caused. There is a problem that (also referred to as uneven gloss) is easily revealed.

The present invention solves the above-mentioned problems. Ink-jet recording is capable of obtaining excellent image quality in which stains are hardly recognized when printed, excellent image fixability, and less likely to cause uneven gloss. It is an object of the present invention to provide an ink set for use with an inkjet recording method, and a recorded matter having excellent image quality in which stains are hardly recognized, having excellent image fixability, and having less uneven gloss.

[0009]

As a result of intensive studies, the present inventors have found that the above object can be achieved by combining specific pigment inks to form an ink set, and completed the present invention. That is, the present invention is as follows. (1) One or more of "a pigment-rich ink containing a pigment, a resin dispersant, and water" and "a pigment, a resin-dispersant, and water, and the concentration of the pigment is the pigment concentration in the pigment-rich ink. One or more of "a pigment light ink that is 1/2 or less of the above", and the acid value of the resin dispersant in the pigment dark ink is smaller than the acid value of the resin dispersant in the pigment light ink. Inkjet recording ink set. (2) The acid value of the resin dispersant in the pigment dark ink is 50 to 120, and the acid value of the resin dispersant in the pigment light ink is 150 or more. Inkjet recording ink set.

(3) The ink set for ink jet recording according to the above (1) or (2), wherein the dark pigment ink is a cyan ink or a magenta ink. (4) The pigment contained in the cyan ink is C.I. I.
Pigment Blue 15: 3, The ink set for inkjet recording according to (3) above. (5) The ink set for inkjet recording according to the above (3) or (4), wherein the pigment concentration of the cyan ink is 3% by weight or more.

(6) The pigment contained in the magenta ink is C.I. I. Pigment Red 122, the ink set for ink jet recording according to (3) above. (7) The ink set for ink jet recording according to (3) or (6) above, wherein the magenta ink has a pigment concentration of 5% by weight or more.

(8) The ink jet recording ink according to any one of the above (1) to (7), wherein the pigment dark ink and the pigment light ink further contain a surfactant and a penetration accelerator. set. (9) The ink set for ink jet recording according to the above (8), wherein the surfactant is acetylene glycol and / or polyorganosiloxane. (10) The penetration enhancer is a glycol ether and / or
Alternatively, the inkjet recording ink set described in (8) above, which is a 1,2-alkanediol.

(11) An ink jet recording method in which ink jet recording is performed using the ink set for ink jet recording according to any one of (1) to (10) above. (12) A recorded matter obtained by the inkjet recording method described in (11) above.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The inkjet recording ink set of the present invention (simply,
"Ink set") is one or more of "a pigment-rich ink containing a pigment, a resin dispersant, and water" and "a pigment, a resin dispersant, and water. One or more of “pigment light ink having a pigment concentration of ½ or less of the pigment dark ink”, and the acid value of the resin dispersant in the pigment dark ink is higher than the acid value of the resin dispersant in the pigment light ink. It is configured to be small. The acid value of the pigment-rich ink is preferably 50 to 120, more preferably 50 to 90. The acid value of the pigment light ink is preferably 150 or more, more preferably 170 to 250. By setting the above-mentioned preferable range, it becomes more difficult for the dirt of the image to be visually recognized. In the present invention, the pigment dark ink and the pigment light ink have different pigment concentrations, except that the acid value of the resin dispersant is different.
The same pigment and other components can be used.

As the pigment that can be used in the pigment dark ink and pigment light ink of the present invention, any pigment can be selected as long as it can be dispersed in the ink by a dispersant. Therefore, such a pigment may be any pigment that emits any color when recorded on a recording medium, and may be either an inorganic pigment or an organic pigment. It may also be a mixture of these.

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. As the organic pigment, azo pigment (including azo lake, insoluble azo pigment, condensed azo pigment, chelate azo pigment, etc.), polycyclic pigment (for example, phthalocyanine pigment, perylene pigment, perinone pigment, anthraquinone pigment, quinacridone pigment, dioxazine pigment, A thioindigo pigment, an isoindolinone pigment, a quinophthalone pigment, etc.), a dye chelate (for example, a basic dye type chelate, an acid dye type chelate, etc.), a nitro pigment, a nitroso pigment, aniline black and the like can be used.

Pigments usable in the present invention include:
Examples of yellow ink pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 1
2, 13, 14, 14C, 16, 17, 24, 34, 3
5, 37, 42, 53, 55, 65, 73, 74, 7
5, 81, 83, 93, 95, 97, 98, 100, 1
01, 104, 108, 109, 110, 114, 11
7, 120, 128, 129, 138, 150, 15
1, 153, 154, 180 and the like.

As the magenta ink pigment,
C. I. Pigment Red 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 1
6, 17, 18, 19, 21, 22, 23, 30, 3
1, 32, 37, 38, 39, 40, 48 (Ca), 4
8 (Mn), 48: 2, 48: 3, 48: 4, 49,
49: 1, 50, 51, 52, 52: 2, 53: 1, 5
3, 55, 57 (Ca), 57: 1, 60, 60: 1,
63: 1, 63: 2, 64, 64: 1, 81, 83, 8
7, 88, 89, 90, 101 (bengara), 104,
105, 106, 108 (Cadmium red), 11
2, 114, 122 (quinacridone magenta), 12
3, 146, 149, 163, 166, 168, 17
0, 172, 177, 178, 179, 184, 18
5, 190, 193, 202, 209, 219 and the like, and C.I. I. Pigment Red 122 is preferred.

The cyan ink pigments include C.I.
I. Pigment Blue 1, 2, 3, 15, 15: 1,
15: 2, 15: 3, 15:34, 16, 17: 1, 2
2, 25, 56, 60, C.I. I. Bat Blue 4, 6
0, 63 and the like, and C.I. I. Pigment Blue 1
5: 3 is preferable.

Other color ink pigments include:
C. I. Pigment Orange 5, 13, 16, 17, 3
6, 43, 51, C.I. I. Pigment Green 1,
4, 7, 8, 10, 17, 18, 36, C.I. I. Pigment Violet 1 (Rhodamine Lake) 3, 5:
1, 16, 19 (quinacridone red), 23, 38 and the like are also included. In addition, processed pigments such as graft carbon whose pigment surface is treated with resin can be used.

Examples of black type include carbon black. Specific examples of such carbon black include No. 2300, No. 900, MCF88, No. 3 manufactured by Mitsubishi Chemical.
3, No.40, No.45, No.52, MA7, MA8, MA100, No2200B
Raven5750, Raven5250, Raven5 made by Colombia
000, Raven3500, Raven1255, Raven700 etc. are Regal 400R, Regal330R, Regal660R, Mogul manufactured by Cabot.
L, Monarch700, Monarch800, Monarch 880, Monarch 90
0, Monarch 1000, Monarch 1100, Monarch 1300, Monar
ch 1400 etc. are Color Black FW1, Color manufactured by Degussa
Black FW2, Color Black FW2V, Color Black FW18, Col
or Black FW200, ColorBlack S150, Color Black S16
0, Color Black S170, Printex 35, Printex U, Printe
x V, Printex 140U, Special Black 6, Special Black
5, Special Black4A, Special Black4 and so on.

The above pigments may be used alone,
In addition, a plurality of types may be selected from within each group or between each group and used in combination.

The particle size of the pigment used in the present invention is
0.2 μm or less is preferable, and more preferably 0.05
Is about 0.15 μm.

The pigment content in the pigment-rich ink is preferably 2 to 10% by weight, more preferably 2 to 6% by weight, based on the total amount of the ink. Further, the content of the pigment in the pigment light ink is 0.
1 to 2% by weight is preferable, and more preferably 0.2 to
It is 1.0% by weight.

When the dark pigment ink is a cyan ink, the pigment concentration of the dark cyan ink is 3% by weight or more, and when the dark pigment ink is a magenta ink, the pigment concentration of the dark magenta ink is 5% by weight or more. Is preferable, and it is possible to obtain a recorded matter which is excellent in color development as well as hardly any stain is recognized.

In the present invention, the pigment contained in the pigment dark ink and the light ink is dispersed in the ink with a resin dispersant, and the resin dispersant is preferably a natural polymer. Specific examples thereof include proteins such as glue, gelatin, casein and albumin, natural gums such as gum arabic and tragacanth,
Examples include glucosides such as savonine, alginic acid and propylene glycol alginate triethanolamine alginate, alginic acid derivatives such as ammonium alginate, and cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose and the like.

Further, as a preferable example of the resin dispersant, a synthetic polymer can be mentioned, and polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, Acrylic resin such as vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer,
Styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-
Methylstyrene-acrylic acid copolymer, styrene-α-
Styrene-acrylic resin such as methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid Copolymers, vinyl acetate-ethylene copolymers, vinyl acetate-fatty acid vinyl ethylene copolymers,
Examples thereof include vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers and vinyl acetate-acrylic acid copolymers, and salts thereof.

Among these, a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and a polymer having a monomer having both a hydrophobic group and a hydrophilic group in the molecular structure are preferable. , The copolymer is a random copolymer,
It may be any of block copolymers. Examples of the above salts include diethylamine, ammonia, ethylamine,
Examples thereof include salts such as triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol and morpholine. These compounds for forming a salt may be at least the neutralization equivalent of the dispersant consisting of an organic substance before forming the salt, but about 1.3 times the neutralization equivalent from the viewpoint of fixability after printing. Is preferable. The weight average molecular weight of these copolymers is preferably 1,000 to 50,000, more preferably 3,000 to 10,000.

When these resin dispersants are used, the addition amount thereof is preferably about 10 to 100% by weight, more preferably 20 to 50% by weight based on the pigment. In the present invention, a particularly preferable resin dispersant is a salt of a styrene- (meth) acrylic acid copolymer. Such a salt of a styrene- (meth) acrylic acid copolymer basically has a structure in which at least a styrene skeleton and a skeleton of a salt of (meth) acrylic acid are contained in the structure, and (meth) is contained in the structure. It may have a skeleton derived from a monomer having another unsaturated group such as an acrylate skeleton. The styrene- (meth) acrylic acid copolymer salt may be either a random copolymer or a block copolymer,
It is produced by a known polymerization method such as radical copolymerization or group transfer polymerization. Such styrene- (meth)
The acid value of the salt of the acrylic acid copolymer is preferably in the range of 50 to 300, more preferably 70 to 150.
The weight average molecular weight is 1,000 to 50,000.
Is preferable, and more preferably 1000 to 1500
The range is 0, more preferably 3000 to 1000
The range is 0.

As the resin dispersant, a commercially available one can be used, and a specific example thereof is John Cryl 68 (molecular weight 1000, manufactured by Johnson Polymer Co., Ltd.).
0, acid value 195), Jonkuriru 680 (molecular weight 390)
0, acid value 215), John Cryl 682 (molecular weight 160
0, acid value 235), Jonkuriru 550 (molecular weight 750
0, acid value 200), Jonkryl 555 (molecular weight 500)
0, acid value 200), Jonkryl 586 (molecular weight 310
0, acid value 105), John Cryl 683 (molecular weight 730
0, acid value 150), B-36 (molecular weight 6800, acid value 2
50) and the like.

The acid value of these resin dispersants can be changed by changing the use ratio of a monomer having a carboxylic acid group (acrylic acid, etc.) and a monomer having no carboxylic acid group (acrylic acid ester, styrene, etc.). It is possible to adjust. Here, the acid value of the resin dispersant refers to the number of milligrams of potassium hydroxide required to neutralize the free fatty acid contained in 1 g of the resin.

In the present invention, the pigment dark ink and the pigment light ink may contain other desired additives in addition to the above-mentioned pigment, resin dispersant and water. Examples of other additives include various surfactants such as nonionic surfactants and cationic surfactants, water-soluble organic solvents as penetration promoters, and moisturizers. The details will be described below. still,
In the present invention, the water contained in the pigment dark ink and the pigment light ink is not limited and may be pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water. It can be preferably used. In addition, it is preferable to use water sterilized by irradiation with ultraviolet rays and addition of hydrogen peroxide because it is possible to prevent the generation of mold, bacteria and the like during long-term storage.

According to a preferred embodiment of the present invention, the pigment dark ink and the pigment light ink (hereinafter collectively referred to as pigment ink) further contain a nonionic surfactant. Examples of such nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide. , And acetylene glycol-based surfactants described later. You may use these in mixture of 2 or more types. According to a preferred aspect of the present invention, the pigment ink preferably further contains an acetylene glycol-based surfactant as the nonionic surfactant. In the present invention, preferred specific examples of the acetylene glycol-based surfactant include compounds represented by the following formula (a).

[0034]

[Chemical 1] [In the above formula, 0 ≦ m + n ≦ 50, R ^{1 *} , R ^{2 *} , R ^{3 *} , and R ^{4 *} are independently an alkyl group (preferably having a carbon number of 1 to 1).
6 alkyl group]

Among the compounds represented by the above formula (a), 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-4-octyne are particularly preferable. -3,6-diol, 3,5-dimethyl-1-hexyne-3-ol and the like can be mentioned. It is also possible to use a commercially available product as the acetylene glycol-based surfactant represented by the above formula (a), and specific examples thereof include Surfynol 82, 104, 440, 465, 485, or TG. (Available from Air Products and Chemicals. Inc.), Olfine STG, Olfine E101
0 (trade name) (above, manufactured by Nisshin Chemical Co., Ltd.) can be mentioned. Two or more kinds of these acetylene glycol-based surfactants may be mixed and used.

In the present invention, it is also preferable to contain polyorganosiloxane as the nonionic surfactant. As the polyorganosiloxane, a compound represented by the following formula (I) can be preferably exemplified.

[0037]

[Chemical 2] (In the formula, R ^{1 to} R ⁷ independently represent a C _1-6 alkyl group, j and k independently represent an integer of 1 or more,
EO represents an ethyleneoxy group, PO represents a propyleneoxy group, m and n represent an integer of 0 or more, provided that m + n represents an integer of 1 or more, and EO and PO represent
The order in [] is not limited and may be random or block. )

In formula (I), R ^{1 to} R ⁷ independently represent a C _1-6 alkyl group, preferably a methyl group. j
And k independently represent an integer of 1 or more, and more preferably 1 or 2. Moreover, m and n represent an integer of 0 or more, provided that m + n represents an integer of 1 or more. Preferably m + n is 2-4.

As the compound of the formula (I), those satisfying j = k = 1 are preferable. In the compound of formula (I), R ^{1 to} R ⁷ all represent a methyl group, j represents 1, and k
Represents 1, l represents 1, m represents an integer of 1 or more,
More preferably, n represents 0.

The amount of the compound of formula (I) added may be appropriately determined, but is preferably 0.03 to 3% by weight, more preferably about 0.1 to 2% by weight, based on the pigment ink.
More preferably, it is about 0.3 to 1% by weight.

The compound of formula (I) is commercially available and can be used. For example, Big Chemie
From Japan Co., Ltd., a silicone surfactant BYK-
347 are available.

As the polyorganosiloxane,
A compound represented by the following formula (II) can also be preferably exemplified.

[0043]

[Chemical 3] (In the above formula, R ^{11 to} R ¹⁹ independently represent a C _1-6 alkyl group, j ′ and k ′ independently represent an integer of 1 or more, and EO represents an ethyleneoxy group, PO represents a propyleneoxy group, m'and n'represent an integer of 0 or more, provided that m '+ n' represents an integer of 1 or more, and EO and PO may have any order within []. It may be random or block.)

In the formula (II), R ^{11 to} R ¹⁸ independently represent a C _1-6 alkyl group, preferably a methyl group.
j'and k'independently represent an integer of 1 or more,
More preferably, it is 1-2. Further, m'and n'represent an integer of 0 or more, provided that m '+ n' represents an integer of 1 or more. Preferably m '+ n' is 2-4.

According to a preferred embodiment of the present invention, the formula (I
As the compound of I), those satisfying j '= k' + 1 are preferable. According to another preferred embodiment of the present invention, as the compound of formula (II), R ^{11 to} R ¹³ each represent a methyl group, j ′ represents 2, k ′ represents 1, and l ′ represents 1. Is preferred, m'represents an integer of 1 or more, and n'represents 0.

The amount of the compound of the formula (II) added may be appropriately determined, but is 0.03 to 3% by weight based on the pigment ink.
Is more preferable, about 0.1 to 2% by weight is more preferable, and about 0.3 to 1% by weight is further preferable.

The compound of formula (II) is commercially available and can be used. For example, from BYK Japan Japan Co., Ltd., silicone surfactant BYK
-345, 346, and 348 are available.

The amount of the nonionic surfactant added is preferably in the range of about 0.1 to 5% by weight, more preferably in the range of about 0.5 to 2% by weight, based on the pigment ink.

The pigment ink used in the present invention may further contain a water-soluble organic solvent as a solvent in addition to water for the purpose of adjusting the moisturizing property of the ink or imparting permeability. In the present invention, the water-soluble organic solvent that adjusts the moisturizing property of the ink is added to the pigment ink according to the present invention as a moisturizing agent or a drying accelerator, and a water-soluble solvent that imparts permeability to the ink. The organic organic solvent is added to the pigment ink according to the present invention as a penetration enhancer.

Specific examples of the water-soluble organic solvent for adjusting the moisturizing property of the ink include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and iso-ptanol. , Monohydric alcohols such as n-pentanol, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, dipropylene glycol, polypropylene glycol, thiodiglycol, hexylene glycol, 1,
3-propanediol, 1,4-butanediol, 1,
5-pentanediol 1,6-hexanediol, 1,
Polyhydric alcohols such as 2,6-hexanetriol and pentaerythritol, 2-pyrrolidone, N-methyl-2
-Pyrrolidone, urea, thiourea, ethylene urea, 1,3
-Dimethyl-2-imidazolidinone and the like.

In the present invention, such a water-soluble organic solvent for adjusting the moisturizing property of the ink is added to the pigment ink as a moisturizing agent, but in the present invention, the moisturizing agent mainly suppresses the drying of the ink. It is used to prevent the solidification of ink at the ejection nozzle of the inkjet recording apparatus. The moisturizers that can be used in the present invention include
In addition to the water-soluble organic solvent described above, for example, lactams such as ε-caprolactam, solid glycerins such as trimethylolpropane and trimethylolethane, saccharides such as maltitol, sorbitol, gluconolactone, and maltose can also be used. is there.

The water-soluble organic solvent that imparts penetrability to the ink, that is, the penetration accelerator, is preferably glycol ether, particularly glycol monoether. In the present invention, the glycol monoether is selected from monoether compounds of glycols such as mono and polyethylene glycol, mono and polypropylene glycol, and selected from compounds represented by the following formula (i). Is preferred. _{R-O- [C x H 2x} -O] y -H (i) [ In the formula, R represents an alkyl group having 1 to 6 carbon atoms, a phenyl group or a benzyl group, preferably a methyl group, an ethyl group, A propyl group or a butyl group, x is 1 to 3,
It is preferably 2 or 3, and y is 1 to 8, preferably 1 to 5, and more preferably 1 to 3]

Specific examples of the penetration enhancer in the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol mono-n-propyl ether. Ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol Monoethyl ether, triethylene glycol mono-n-butyl ether Ter, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono- iso-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono- Examples include iso-propyl ether.

Of these, ethylene glycol mono-n-
Butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, propylene glycol monobutyl ether,
Or dipropylene glycol monobutyl ether is preferable. It is known that these have high compatibility with the 1,2-alkanediol described below.

As the penetration enhancer in the present invention, 1,2-alkanediol is also preferable. The 1,2-alkanediol has a carbon number of 4 to 10,
The use of 2-alkanediol is preferred. Two or more kinds of 1,2-alkanediols may be mixed and added.
Preferred 1,2-alkanediols are 1,2-
Butanediol, 1,2-pentanediol, 1,2-
It is selected from the group consisting of hexanediol, 1,2-heptanediol, and mixtures thereof.
These are more preferable because they have excellent penetrability into a recording medium. More preferred 1,2-alkanediol is
It is 1,2-hexanediol or 1,2-pentanediol, and most preferably 1,2-hexanediol.

As the penetration enhancer in the present invention, 1,
It is preferable to use a combination of 2-alkanediol and glycol ether. By using them in combination, it is possible to impart the same penetrability to the pigment ink with a smaller addition amount as compared with the case of using the 1,2-alkanediol alone. Further, it is possible to reduce the wetting of the ink to the ejection nozzles of the inkjet printing apparatus. Further, ink adhesion to the ejection nozzle caused by addition of 1,2-alkanediol can be more effectively prevented by using glycol ether together with 1,2-alkanediol. Therefore, combined with the effect of reducing the addition amount described above, it is possible to prevent the ink from adhering to the ejection nozzles of the inkjet recording apparatus, and to provide a pigment ink having high printing stability.

In the present invention, when the pigment ink contains a glycol ether, the glycol ether is preferably added in an amount in the range of 0.25 to 10% by weight with respect to each pigment ink. Within the above range, higher penetrability can be obtained when used in combination with a 1,2-alkanediol, and the viscosity of the printable ink can be adjusted in combination with other additives. Further, the ratio (weight ratio) of glycol monoether to 1,2-alkanediol is preferably in the range of 1: 5 to 5: 1, and more preferably in the range of 1: 2 to 2: 1. .

In the above description, the water-soluble organic solvent has been described in terms of the organic solvent for adjusting the moisturizing property and the organic solvent for imparting the penetrating property. In some cases, permeability is imparted, and in some cases, the organic solvent mentioned as imparting permeability also acts as a moisturizing agent.

The pigment ink according to the present invention has the purpose of promoting penetration, obtaining ejection reliability, and obtaining a good image.
Further, it may contain a surfactant. As such a surfactant, in addition to the above-mentioned nonionic surfactant,
For example, anionic surfactants (for example, sodium dodecyl benzene sulfonate, sodium laurate, ammonium salt of polyoxyethylene alkyl ether sulfate, etc.), cationic surfactants and amphoteric surfactants can be mentioned. These may be used alone or in combination of two or more. The surface tension of the pigment ink according to the present invention is about 20 to 50 mN / m, preferably about 25 to 40 mN / m.

The pigment ink in the present invention may further contain a humectant. The humectant is used to suppress the drying of the ink and prevent the solidification of the ink at the ejection nozzle of the inkjet recording apparatus. As the moisturizer, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol,
Polyols such as polypropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol 1,6-hexanediol, 1,2,6-hexanetriol and pentaerythritol, 2
-Pyrrolidone, N-methyl-2-pyrrolidone and the like are preferable, and the water-soluble organic solvent is selected from materials having moisture retention and hygroscopicity. Alternatively, ureas such as urea, thiourea, ethylene urea and 1,3-dimethylimidazolidinone,
Laclams such as ε-caprolactam, solid glycerins such as trimethylolpropane and trimethylolethane,
Sugars such as maltitol, sorbitol, gluconolactone and maltose are preferable and selected from water-soluble hygroscopic materials.

The pigment ink according to the present invention further comprises a nozzle clogging preventive agent, an antiseptic agent, an antioxidant / ultraviolet absorber, a conductivity adjusting agent, a pH adjusting agent, a dissolution aid, a viscosity adjusting agent, an oxygen absorbing agent, and the like. It may further comprise other optional components of

Examples of preservatives include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzothiazolin-3-one (ICI company). Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-
2, Proxel TN) and the like.

Examples of pH adjusters, solubilizers, or antioxidants include amines such as diethanolamine, triethanolamine, propanolamine, morpholine and their modified products, potassium hydroxide, sodium hydroxide, Inorganic salts such as lithium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide (tetramethylammonium, etc.), potassium carbonate, sodium carbonate,
Carbonates such as lithium carbonate and other phosphates, ureas such as N-methyl-2-pyrrolidone, urea, thiourea and tetramethylurea, alohanates such as alohanate and methylallohanate, biuret, dimethylbiuret, tetramethyl Examples include biurets such as biuret, and L-ascorbic acid and salts thereof. In the present invention, the other optional components described above may be used alone or as a mixture of a plurality of types selected in each group and between each group.

In the present invention, the amounts of all components of the pigment ink are such that the viscosity of the pigment ink is 10 mPas at 20 ° C.
It is preferably selected to be s or less.

The pigment ink in the present invention can be produced by dispersing and mixing the above-mentioned components by an appropriate method commonly used. A suitable disperser is preferably used for the mixture excluding the organic solvent and volatile components (eg, ball mill, roll mill, sand mill, attritor, agitator mill, Henschel mixer, colloid mill, jet mill, ong mill, ultrasonic homogenizer, etc.). It is preferable that the organic solvent and the volatile component are added after the above-mentioned mixing is carried out to obtain a homogeneous composition. Then, in order to remove coarse particles and foreign substances, it is preferable to carry out pressure reduction and pressure filtration using a metal filter, a membrane filter or the like, or centrifugation.

The constitution of the ink provided in the ink set of the present invention has been described above. In the ink set of the present invention, one or more of the pigment dark inks are black ink, magenta ink, cyan ink and yellow ink. At least one selected from the group, and at least one pigment light ink is preferably selected from the group consisting of black ink, magenta ink, cyan ink, and yellow ink.

That is, the ink set in which the pigment dark ink is black ink and the pigment light ink is black, the pigment dark ink is black ink and magenta ink,
An ink set in which the pigment light ink is black ink and magenta ink, an ink set in which the pigment dark ink is black ink and magenta ink, an ink set in which the pigment light ink is black ink and cyan ink, a pigment dark ink is black ink, magenta ink and The present invention may include an ink set composed of various combinations such as an ink set that is a cyan ink and the pigment light ink is a black ink, a cyan ink, and a yellow ink.

A preferred ink set in the present invention is an ink set in which one or more pigment dark inks and one or more pigment light inks are configured to correspond in hue. Corresponding to the hue, for example, when the pigment dark ink is black ink and magenta ink, an ink set in which the pigment light ink is black ink and magenta ink, the pigment dark ink is black ink, When the ink is magenta ink and cyan ink, the pigment light ink is black ink, the ink set that is magenta ink and cyan ink, the pigment dark ink is black ink, magenta ink,
When it is cyan ink and yellow ink, it means an ink set or the like in which the pigment light ink is black ink, magenta ink, cyan ink and yellow ink. With such a configuration, it is possible to control the ink Duty of the pigment dark ink and the pigment light ink, respectively, and to print a specific hue without graininess.

When ink jet recording is carried out using such an ink jet recording ink set of the present invention, it is possible to provide excellent image quality in which dirt is hardly recognized.

In the ink jet recording method of the present invention, any method can be used as long as it is a system in which the pigment dark ink and the pigment light ink are ejected as droplets from fine nozzles and the droplets are attached to the recording medium. it can. As such a method, for example, a method using an inkjet head having a mechanism based on the response of an electrostrictive element, that is, a pressure and a print information signal are simultaneously applied to the ink liquid by the electrostrictive element, and an ink droplet is ejected by a deformed deformation. A method of forming, a method of rapidly expanding the volume of the ink liquid by the action of thermal energy,
Examples thereof include an electrostatic suction method and a method of forcibly ejecting ink droplets by applying pressure to the ink liquid with a small pump and mechanically vibrating the nozzle with a crystal oscillator or the like. According to a more preferred aspect of the present invention, the inkjet recording method according to the present invention is preferably a method using an inkjet head that forms ink droplets by mechanical deformation of an electrostrictive element.

The recorded matter of the present invention obtained as described above has an excellent image quality with almost no stain.

[0072]

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(1) Preparation of Ink Composition Preparation of Ink Composition A1 As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 80, molecular weight: 7000) 50 g, potassium hydroxide 4.5.
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion A1. The obtained cyan pigment dispersion A1 was added to 2
0 g, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie) are mixed, and ultrapure water is added to bring the total amount to 1
It was set to 00 g. Further, the pH of this mixed solution was adjusted to 9.5 by using triethanolamine as a pH adjuster, and
After stirring for an hour, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition A1.

Preparation of Ink Composition A1 'As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 80, molecular weight: 7000) 50 g, potassium hydroxide 4.5.
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The obtained dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion A1 ′. Cyan pigment dispersion A1 'obtained
Was mixed with 10 g of glycerol, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie), and ultrapure water was further added to make 100 g. Furthermore, this mixed solution was adjusted to pH 9.5 by using triethanolamine as a pH adjuster,
After stirring for 2 hours, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition A1 ′.

Preparation of Ink Composition A2 As a magenta pigment, C.I. I. Pigment Red 122 100 g, styrene-acrylic acid resin (acid value: 80, molecular weight: 7000) 20 g, potassium hydroxide 2 g, and water 250 g were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. It was The resulting undiluted dispersion was passed through a membrane filter (Japan Millipore.
Co., Ltd.) to remove coarse particles and dilute with water to a pigment concentration of 20% to prepare a magenta pigment dispersion A.
2 was prepared. The obtained magenta pigment dispersion A2 was added to 30
g, 10 g of glycerin, 5 g of 1,2-hexanediol and BYK-347 (trade name of BIC Chemie)
Was mixed with 0.5g and ultrapure water was added to bring the total amount to 100.
It was set to g. Further, the pH of this mixed solution was adjusted to 9.5 using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition A2.

Preparation of Ink Composition A2 'As magenta pigment, C.I. I. Pigment Red 122 100 g, styrene-acrylic acid resin (acid value: 80, molecular weight: 7000) 20 g, potassium hydroxide 2 g, and water 250 g were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. It was The resulting undiluted dispersion was passed through a membrane filter (Japan Millipore.
Co., Ltd.) to remove coarse particles and dilute with water to a pigment concentration of 20% to prepare a magenta pigment dispersion A.
2'was prepared. 15 g of the obtained magenta pigment dispersion A2 ′, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie) were mixed, and ultrapure water was further added. 1 for all
It was set to 00 g. Further, the pH of this mixed solution was adjusted to 9.5 by using triethanolamine as a pH adjuster, and
After stirring for an hour, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition A2 ′.

Preparation of Ink Composition A3 To 20 g of the cyan dispersion A1 prepared above, 10 g of glycerin, 5 g of triethylene glycol monobutyl ether and 1 g of Olfine E1010 (trade name of Nissin Chemical Industry Co., Ltd.) were mixed. Then, ultrapure water was further added to bring the total amount to 100 g. Further, this mixed solution was adjusted to pH 9.5 using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition A3.

Preparation of Ink Composition A4 As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7,000) 50 g, potassium hydroxide 10
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion A4. The obtained cyan pigment dispersion A4 was added to 2
0 g, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie) are mixed, and ultrapure water is added to bring the total amount to 1
It was set to 00 g. Further, the pH of this mixed solution was adjusted to 9.5 by using triethanolamine as a pH adjuster, and
After stirring for an hour, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition A4.

Preparation of Ink Composition A4 'As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7,000) 50 g, potassium hydroxide 10
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion A4 ′. Cyan pigment dispersion A4 'obtained
Was mixed with 10 g of glycerol, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie), and ultrapure water was further added to make 100 g. Furthermore, this mixed solution was adjusted to pH 9.5 by using triethanolamine as a pH adjuster,
After stirring for 2 hours, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition A4 ′.

Preparation of Ink Composition A5 As a magenta pigment, C.I. I. Pigment Red 122, 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7000) 20 g, potassium hydroxide 2 g,
And 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a magenta pigment dispersion A5. 1 to the obtained magenta pigment dispersion A5
5 g, 10 g of glycerin, 5 g of 1,2-hexanediol and 0.5 g of BYK-347 (trade name of BYK-Chemie) were mixed, and ultrapure water was further added to bring the total amount to 1
It was set to 00 g. Further, the pH of this mixed solution was adjusted to 9.5 by using triethanolamine as a pH adjuster, and
After stirring for an hour, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition A5.

Preparation of Ink Composition B1 As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7,000) 50 g, potassium hydroxide 10
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion B1. The obtained cyan pigment dispersion B1 was added to 5
g, glycerin 15 g, 1,2-hexanediol 5 g and BYK-347 (trade name of BYK Chemie)
Was mixed with 0.5g and ultrapure water was added to bring the total amount to 100.
It was set to g. Further, this mixed solution was adjusted to pH 9.5 by using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition B1.

Preparation of Ink Composition B1 ′ As a cyan pigment, C.I. I. Pigment Blue 15: 3 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7,000) 50 g, potassium hydroxide 10
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting undiluted dispersion was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a cyan pigment dispersion B1 ′. Cyan pigment dispersion B1 ′ obtained
2.5 g, glycerin 15 g, 1,2-hexanediol 5 g and BYK-347 (trade name of BYK-Chemie Co., Ltd.) 0.5 g were mixed, and ultrapure water was further added to bring the total amount to 100 g. Further, this mixed solution was adjusted to pH 9.5 by using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition B1 ′.

Preparation of Ink Composition B2 As a magenta pigment, C.I. I. Pigment Red 122, 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7000) 20 g, potassium hydroxide 4 g,
And 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a magenta pigment dispersion B2. The obtained magenta pigment dispersion B2 was added to 5
g, glycerin 15 g, 1,2-hexanediol 5 g and BYK-347 (trade name of BYK Chemie)
Was mixed with 0.5g and ultrapure water was added to bring the total amount to 100.
It was set to g. Further, this mixed solution was adjusted to pH 9.5 by using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition B1.

Preparation of Ink Composition B2 'As magenta pigment, C.I. I. Pigment Red 122, 100 g, styrene-acrylic acid resin (acid value: 180,
Molecular weight: 7000) 20 g, potassium hydroxide 4 g,
And 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a magenta pigment dispersion B2 ′. The obtained magenta pigment dispersion B2 '
Of 3.75 g, glycerin of 15 g, 1,2-hexanediol of 5 g and BYK-347 (trade name of BYK-Chemie Co., Ltd.) of 0.5 g were mixed, and ultrapure water was further added to bring the total amount to 100 g. Furthermore, this mixed solution was adjusted to pH 9.5 using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition B2 ′.

Preparation of Ink Composition B3 To 5 g of the cyan dispersion B1 prepared above, 15 g of glycerin, 5 g of triethylene glycol monobutyl ether and 1 g of Olfine E1010 (trade name of Nissin Chemical Industry Co., Ltd.) were mixed. Then, ultrapure water was further added to bring the total amount to 100 g. Furthermore, this mixed solution was adjusted to pH 9.5 using triethanolamine as a pH adjuster, stirred for 2 hours, and then filtered through a membrane filter having a pore size of 1.2 μm to prepare an ink composition B3.

Preparation of Ink Composition B4 As a magenta pigment, C.I. I. Pigment Red 122 100 g, styrene-acrylic acid resin (acid value: 80, molecular weight: 7000) 50 g, potassium hydroxide 4.5.
g and 250 g of water were mixed, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. The resulting dispersion stock solution was filtered through a membrane filter (manufactured by Japan Millipore Limited) having a pore size of 8 μm to remove coarse particles, and diluted with water to a pigment concentration of 20% to prepare a magenta pigment dispersion B4. Magenta pigment dispersion B4 obtained
5 g, glycerin 10 g, 1,2-hexanediol 5 g and BYK-347 (trade name of BYK-Chemie Co., Ltd.) 0.5 g were mixed, and ultrapure water was further added to bring the total amount to 1
It was set to 00 g. Further, the pH of this mixed solution was adjusted to 9.5 by using triethanolamine as a pH adjuster, and
After stirring for an hour, the mixture was filtered through a membrane filter having a pore size of 1.2 μm to prepare ink composition B4.

(2) Preparation of Ink Set Using each of the ink compositions obtained above, ink sets of Examples and Comparative Examples were prepared. (Ink set of Example 1) Dark ink is ink A1, cyan ink set of light ink is B1 (ink set of Example 2) Dark ink is ink A2, light ink is magenta ink set of ink B2 (Example 3) Ink set) dark ink is ink A3, light ink is ink B3, cyan ink set (ink set of Example 4) dark ink is ink A1 ′,
Cyan ink set in which light ink is ink B1 ′ (ink set in Example 5), dark ink is ink A2 ′,
Magenta ink set of light ink is ink B2 '(ink set of comparative example 1) Dark ink is ink A2, magenta ink set of light ink is ink B4 (ink set of comparative example 2) Dark ink is ink A4, light ink is Cyan ink set of ink B1 (ink set of Comparative Example 3) dark ink is ink A5, light ink is magenta ink set of ink B2 '(ink set of Comparative Example 4) dark ink is ink A4',
Cyan ink set with light ink B1 '

(3) Evaluation (Ink Transfer) The ink sets of Examples and Comparative Examples were
Five types of color patches in which the dark cyan ink and the light cyan ink or the dark magenta ink and the light magenta ink cartridge of the inkjet printer PM900C (manufactured by Seiko Epson Corporation) are filled and the mixing ratio of the dark and light inks is changed are as follows. Printed on four types of print media.
Each color patch was 2 cm square, and the printing duty was set so that the total of the dark ink and the light ink was 100%. In addition, I chose "plain paper / clean" as the print mode.

MC photo paper MC glossy paper Super fine paper (above Seiko Epson Corporation) Plain paper Xerox P (Xerox Co.)

Whether or not the paper roller passing over the color patch transfers the ink to the non-printed portion was judged according to the following criteria. Judgment A Judgment that ink transfer does not occur on any media B Judgment that ink transfer occurs on 1 or 2 papers C Judge transfer occurs on 3 or more papers

(Evaluation of Fixability) The ink sets of Examples and Comparative Examples were filled in an ink cartridge of a dark cyan ink and a light cyan ink of an ink jet printer PM900C (manufactured by Seiko Epson) or an ink cartridge of a dark magenta ink and a light magenta ink. Then, printing was performed on MC glossy paper.
After 30 minutes of printing, the printed part was rubbed strongly with a finger and evaluated according to the following criteria. Judgment A No stain occurs Judgment B Slight stain Judge C stain

(Evaluation of gloss unevenness) The ink sets of the examples and the comparative examples were used in the ink jet printer PM900C.
(SEIKO EPSON CORPORATION) dark cyan ink and light cyan ink, or dark magenta ink and light magenta ink cartridges were filled, 10% on MC photo paper,
20%, 40%, 60%, 80%, 100% printing du
The color patch was printed at ty. Judgment A Even if the print duties are different, the difference in gloss is hardly noticeable. Judgment B Differences in gloss in different print duties are recognized, but not noticeable. Judgment C I am worried about the difference in gloss between different print duties.

(Evaluation of Coloring Property) The ink sets of Examples and Comparative Examples were filled in the ink cartridges of dark cyan ink and light cyan ink of inkjet printer PM900C (manufactured by Seiko Epson Corp.) or dark magenta ink and light magenta ink. Then, a color patch was printed on the MC matte paper (manufactured by Seiko Epson) with a printing duty of 100%. One day after printing, the optical density (OD) of the color patch was measured and judged according to the following criteria. Judgment A OD is 1.3 or more Judgment B OD is 1.0 or more and less than 1.3

The ink components of the ink sets of Examples and Comparative Examples and the evaluation results are summarized in Tables 1 and 2 below.
Shown in.

[0095]

[Table 1]

[0096]

[Table 2]

As shown in Table 1, it can be seen that the ink sets of Examples 1 to 5 have no ink transfer, good ink fixability, and almost no uneven gloss.
Particularly, according to the ink set of Examples 1 and 3 in which the pigment concentration of the dark cyan ink is 3% by weight or more, and the ink set of Example 2 in which the pigment concentration of the dark magenta ink is 5% by weight or more. It was possible to obtain a recorded matter having excellent color development without causing ink transfer. On the other hand, as shown in Table 2, according to the ink sets of Comparative Examples 1 to 4, in which the pigment dark ink and the pigment light ink have the same acid value, respectively.
It can be seen that the fixability of the ink is poor and the gloss is uneven. Especially, the acid value of both pigment dark ink and pigment light ink is 1
When the ink set of Comparative Examples 2 to 4 set to 80 was used, ink transfer occurred, and the ink set of Comparative Example 2 in which the pigment concentration of the dark magenta ink was 5% by weight or more was excellent in color development. However, the ink transfer remarkably occurred.

[0098]

As described above, according to the present invention,
When printing, it is possible to obtain excellent image quality with almost no stains recognized, excellent image fixability, and an inkjet recording ink set and inkjet recording method in which uneven gloss is less likely to occur, and stains hardly recognized. It is possible to provide a recorded matter having excellent image quality, excellent image fixability, and less likely to cause uneven gloss.

Claims (12)

[Claims] 1. One or more of "a pigment-rich ink containing a pigment, a resin dispersant, and water" and "a pigment, a resin-dispersant, and water, wherein the concentration of the pigment is in the pigment-rich ink. One or more of “pigment light ink having a pigment concentration of ½ or less”, and the acid value of the resin dispersant in the pigment dark ink is smaller than the acid value of the resin dispersant in the pigment light ink. The inkjet recording ink set configured as described above. 2. The acid value of the resin dispersant in the pigment dark ink is 50 to 120, and the acid value of the resin dispersant in the pigment light ink is 150 or more. The inkjet recording ink set described above. 3. The dark pigment ink is cyan ink or magenta ink.
The ink set for ink jet recording according to. 4. The pigment contained in the cyan ink is
C. I. Pigment Blue 15: 3. The ink set for ink jet recording according to claim 3, wherein the ink set is Pigment Blue 15: 3. 5. The pigment concentration of the cyan ink is 3% by weight.
It is above, The ink set for inkjet recording of Claim 3 or 4 characterized by the above-mentioned. 6. The pigment contained in the magenta ink,
C. I. Pigment Red 122. The ink set for ink jet recording according to claim 3, wherein the ink set is Pigment Red 122. 7. The ink set for ink jet recording according to claim 3, wherein the magenta ink has a pigment concentration of 5% by weight or more. 8. The ink set for ink jet recording according to claim 1, wherein each of the pigment dark ink and the pigment light ink further contains a surfactant and a penetration enhancer. . 9. The ink set for ink jet recording according to claim 8, wherein the surfactant is acetylene glycol and / or polyorganosiloxane. 10. The ink set for ink jet recording according to claim 8, wherein the penetration enhancer is glycol ether and / or 1,2-alkanediol. 11. An inkjet recording method for performing inkjet recording using the ink set for inkjet recording according to claim 1. 12. A recorded matter obtained by the ink jet recording method according to claim 11.