JP5273422B2 - Ink jet recording ink, ink set, ink cartridge, recording apparatus, and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment ink for ink jet recording excellent in delivery stability and storage stability and capable of giving a high print quality and an image fastness even when used for high-speed printing on plain paper; and an ink set, an ink jet recording method, an ink cartridge, and a recording apparatus using the same. SOLUTION: The ink for ink jet recording contains a polymer emulsion containing polymer particles containing a colorant insoluble or hardly soluble in water; at least one wetting agent selected from among glyceral, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane; a polyol or a glycol ether; a surfactant; a water-soluble organic solvent; and water, and has a viscosity at 25 deg.C of 5 mPa.sec or higher.

Description

  The present invention relates to a pigment ink, an ink set, an ink cartridge, a recording apparatus, and a recording method suitable for inkjet recording, and particularly high-quality with good color tone with less feathering and color bleeding when printed on plain paper at high speed. Pigment ink for inkjet recording, which provides images, images with excellent image fastness such as water resistance and light resistance, excellent storage stability, no clogging of the head during printing, and excellent ejection stability And an ink set.

  Inkjet printers have been remarkably popular due to the advantages of low noise and low running cost, and color printers that can print on plain paper have come to the market. However, it satisfies all required characteristics such as image color reproducibility, durability, light resistance, image drying, character bleeding (feathering), color boundary bleeding (color bleed), duplex printing, and ejection stability. It is very difficult to do so, and the ink to be used is selected from the characteristics that are given priority according to the application. In particular, it has been difficult to satisfy these characteristics in a printer that performs high-speed printing on plain paper.

  Inks used for ink jet recording generally contain water as a main component and contain a coloring agent and a wetting agent such as glycerin for the purpose of preventing clogging. As the colorant, a dye is used because of its excellent color developability and stability. However, the light resistance, water resistance and the like of an image obtained using a dye-based ink are inferior. The water resistance is improved to some extent by improving the ink jet recording paper having an ink absorbing layer, but the plain paper is not satisfactory.

  In recent years, in order to improve these problems, a pigment ink using an organic pigment or a pigment such as carbon black as a colorant instead of a dye has been studied. Since the pigment is insoluble in water, it is used as a water-based ink in which the pigment is mixed and dispersed together with a dispersant and stably dispersed in water. By using a pigment, water resistance and light resistance are imparted, but other properties cannot be achieved at the same time. In particular, when high-speed printing is performed on plain paper, it is difficult to obtain a high image density and color developability, and bleeding on characters, color boundaries, and double-sided printing are not sufficiently satisfactory.

  In addition, in ink jet recording, since stable ink droplet ejection is required from the fine nozzles of the ink jet recording head, it is necessary that ink solidification does not occur due to drying of the orifice of the ink jet recording head. However, when the ink containing the above-described dispersant is used for ink jet recording, the resin or the like forming the dispersant is not re-dissolved after adhering to the orifice, etc. In some cases, discharge or the like occurs. In particular, when printing is suspended for a long period of time, clogging of nozzles and the like is likely to occur, and thickened ink accumulates in the maintenance mechanism such as the nozzle cap and the suction tube, which may impair the function of the maintenance mechanism. There was something. In addition, when printing is paused for the first time, or when a printing pause period is set for the nozzle corresponding to the blank while printing a document or image with a blank, printing failure (intermittent) due to disturbance of the ink droplet ejection direction. There were many problems such as defective discharge. In addition, water-based pigment ink containing a dispersant is viscous, causing resistance in the path to the nozzle tip when performing continuous ejection and high-speed printing over a long period of time, making ejection unstable and making smooth recording difficult. There was also a problem of becoming.

In order to cope with these problems, many inks for inkjet recording using emulsions of colored polymer particles, particularly polyester-based or vinyl-based polymer particles, have been reported (Japanese Patent Laid-Open Nos. 2000-191972 and 2000-191968, JP 2000-191967, JP 2000-53900, JP 2000-53899, JP 2000-53898, JP 2000-53897, JP 2000-44852, JP 2000-26775, JP-A 2000-7963, JP-A 2000-7962, JP-A 9-241565, JP-A 9-2117030, JP-A 9-183932, JP-A 9- No. 183931, JP-A-9-286939, JP-A-9- No. 57565, JP-A-10-46082, JP-A-10-46092, JP-A-10-60327, JP-A-10-273610, JP-A-10-279851, JP-A-10-298462 JP-A-10-298467, JP-A-11-217528, JP-A-10-338829, JP-A-10-316918, JP-A-11-256083, JP-A-11-323226, Japanese Patent No. 3065950).
In order to improve these problems, JP-A-2000-212486 contains a pigment, pigment concentration, water-soluble dispersant, penetrant ink, and a specific polyhydric alcohol alkyl ether derivative. Ink, and these ink sets are disclosed. Since the disclosed ink is super-permeable, it has sufficient drying properties even in high-speed printing, and discharge stability is ensured. However, the image density and color reproducibility of plain paper is higher than that of dye-based inks. Although it is inferior, it blurs characters, blurs color boundaries, and double-sided printability is improved compared to conventional inkjet recording images, but it is used for recording images such as electrophotographic methods used for printing on plain paper in the market. It was inferior in comparison and required further improvement.

  In addition, an ink containing a colorant-encapsulating resin dispersion in which a colorant is insoluble in water and encapsulated in a dispersible resin has been disclosed as means for improving image durability. However, there is a problem that sufficient image density cannot be obtained when carbon black is used as a colorant. Further, when a color organic pigment is used as the colorant, the image density and color reproducibility on plain paper are inferior to those of dye inks in the conventionally known ink formulations. Further, the color boundary between black and yellow in an ink set in which these colorant-encapsulating resin-dispersed black ink and color ink are combined is not satisfactory.

  As another dispersion method, there is a so-called self-dispersion type pigment ink that can be stably dispersed without using a dispersant. In black pigment inks, as described in JP-A-5-186704 and JP-A-8-3498, by introducing a hydrophilic group on the surface of carbon, the pigment can be stably used without using a dispersant. So-called self-dispersing carbon black that can be dispersed has been developed. Further, as described in JP-T-2000-513396, color pigments that can be stably dispersed without using a dispersant have also been developed for color pigment-based inks.

  When these self-dispersing pigment inks are combined, the color image on plain paper has low saturation, and the scratch resistance on special glossy paper is poor. When a resin emulsion is added to improve the scratch resistance, there is a drawback that the dispersion stability of the ink is lowered and the ejection stability is impaired.

  In addition, as an ink set composed of black ink and color ink, an ink set composed of black ink having self-dispersing carbon black and color ink containing a color material having a reverse polarity to the color material of the black ink Is disclosed in Japanese Patent Laid-Open No. 10-140064. Japanese Laid-Open Patent Publication No. 2000-191972 discloses an ink set having different ionic properties of the colorant-containing resin dispersed ink. However, printed materials using these ink sets have improved color boundary bleeding, but other plain paper properties are still unsatisfactory.

Problems to be solved by the invention

  The present invention eliminates such conventional drawbacks, and provides a color pigment ink for ink jet recording, a suitable ink jet recording method using the ink, an ink cartridge containing the ink, and a recording apparatus equipped with the ink cartridge. Even when printing on plain paper at high speed using the inkjet recording method, it is excellent in ejection stability and storage stability, and (1) good color tone, (2) high image density, (3) characters , Recorded images with high sharpness without blurring and blurring (hereinafter referred to as feathering) in the periphery of the image, (4) blurring between different colors (color bleed), and (5) strikethrough that can withstand double-sided printing With little image (6) Pigment ink for ink jet recording, ink set, ink jet recording capable of giving image fastness such as water resistance and light resistance Law, the ink cartridge, it is an object of the present invention is to provide a recording apparatus.

Means for solving the problem

  As a result of intensive studies on the above problems, the present inventors have found that an ink composed of a specific wetting agent, a penetrating agent, and a water-soluble organic solvent using an emulsion in which a colorant is contained in polymer fine particles is a conventional ink. Compared with high viscosity but low surface tension, high-speed printing on plain paper, the vehicle penetrates quickly and the colorant component tends to remain on the surface. The present inventors have found that an image having a color density and little show-through can be obtained, leading to the present invention.

  Further, in an ink set composed of black ink and color ink, the color ink having the above-described configuration containing colored polymer fine particles, and high viscosity and low surface tension as in the case of color pigment ink using self-dispersing carbon black as a coloring material. When combined with the black ink, high-speed printing on plain paper has a high black image density, very little blurring of the color boundary between black and color, excellent color development, and excellent double-sided printing with little show-through. I found that I can get images.

  The first feature of the present invention of the recording ink is that a low surface tension aqueous ink or ink set having a surface tension of 40 dyn / cm or less at 25 ° C. is used as the ink. As a result of studies by the present inventors on various means for improving the drying property of the recorded image, it is possible to adjust the surface tension of the ink so that it is 40 dyn / cm or less. On the other hand, it is based on the finding that rapid osmotic drying is possible. In addition, by setting the ink surface tension to 40 dyn / cm or less, wetting of the ink to the head member is improved, and the frequency response is improved even with high viscosity ink of 8 cps (25 ° C.) or more, and the ejection stability is remarkably improved. By improving. This low surface tension ink can be achieved by using a polyol or glycol ether having 8 to 11 carbon atoms and an anionic or nonionic surfactant.

  The second feature of the present invention is that the printing quality is remarkably improved by using a high viscosity ink or ink set of 5 cps or more, preferably 8 cps (25 ° C.) or more. The low-viscosity ink of about 3 cps (25 ° C.) that has been used in conventional ink jet printers has about 70% of water in the ink, but the high-viscosity ink of about 8 cps (25 ° C.) has about 50% or less. When the ink droplets land on the paper surface, the water evaporation rate becomes as high as 2.0 to 3.0 times. For this reason, the speed at which high-concentration pigments agglomerate on the paper surface is increased, and bleeding (feathering) is almost eliminated.

  The third feature of the present invention is that the concentration of the polymer emulsion containing the colorant in the ink is 8 wt% or more, preferably 10 wt% or more in terms of solid content. In the case where an ink set is formed using self-dispersing carbon black as a coloring material, the pigment concentration of the black ink is 6 wt% or more, preferably 8 wt% or more. By increasing the polymer emulsion concentration or the pigment concentration, the viscosity of the ink increases, the pigment tends to stay on the paper surface and the color density and color tone are improved, and feathering is almost eliminated.

  The fourth feature of the present invention is that glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexane rather than the conventionally used low viscosity wetting agent in which ethylene glycol (diethylene glycol) and glycerin are mixed. A high-viscosity wetting agent prepared by mixing glycerin with at least one high-viscosity wetting agent selected from diol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane. There is to use. When a high viscosity wetting agent is used, a high viscosity ink can be achieved in combination with a high pigment concentration.

  The ink composition of the present invention is a recording ink having the following constitution and an ink viscosity of 5 cps or more, preferably 8 cps (25 ° C.) or more. A coloring material for printing and water for dispersing the same are essential components, and a wetting agent, a water-soluble organic solvent, an anionic or nonionic surfactant, emulsion, preservative, pH control, which are added as necessary. Consists of formulations. Wetting agents 1 and 2 are mixed in order to take advantage of the characteristics of each wetting agent and to adjust the viscosity, but wetting agents 1 and 2 are not necessarily included.

(1) Coloring agent (2) Wetting agent 1 (Glycerin)
(3) Wetting agent 2 (Selected from 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane At least one type)
(4) Water-soluble organic solvent (5) Anionic or nonionic surfactant (6) Polyol or glycol ether having 8 to 11 carbon atoms (7) Preservative (8) pH adjuster (9) Pure water

Hereinafter, components of each ink will be described.
The color material is made of a polymer emulsion in which a polymer fine particle contains a water-insoluble or hardly soluble color material. In the present invention, “containing a color material” means either or both of a state in which a color material is enclosed in polymer fine particles and a state in which the color material is adsorbed on the surface of the polymer fine particles. In this case, it is not necessary for all of the color material blended in the ink of the present invention to be enclosed or adsorbed in the polymer fine particles, and the color material is dispersed in the emulsion as long as the effects of the present invention are not impaired. Also good. The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer. In the present invention, water-insoluble or poorly water-soluble means that the coloring material does not dissolve 10 parts by weight or more with respect to 100 parts by weight of water at 20 ° C. This means that no separation or sedimentation is observed. Examples of the coloring material include dyes such as oil-soluble dyes and disperse dyes, pigments, and the like. Oil-soluble dyes and disperse dyes are preferable from the viewpoint of good adsorption and encapsulation, but pigments are preferably used from the light resistance of the obtained image.

  Each dye used in the present invention is preferably dissolved in an organic solvent, for example, a ketone solvent in an amount of 2 g / liter or more, preferably 20 to 600 g / liter, from the viewpoint of efficiently impregnating the polymer fine particles. Is more preferable.

  Examples of the pigment used in the present invention include carbon black as a black pigment, and examples of the color pigment include anthraquinone, phthalocyanine blue, phthalocyanine green, diazo, monoazo, pyranthrone, perylene, heterocyclic yellow, quinacridone, and (thio) indigoid. Including. Representative examples of phthalocyanine blue include copper phthalocyanine blue and its derivatives (Pigment Blue 15). Representative examples of quinacridone include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. Representative examples of anthraquinones include pigment red 43, pigment red 194 (perinone red), pigment red 216 (brominated pyrantrone red) and pigment red 226 (pyrantron red). Representative examples of pyrerin are Pigment Red 123 (Bell Million), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (Yellow Shade Red) and Pigment Red. 224. Representative examples of thioindigoid include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36 and Pigment Violet 38. Representative examples of heterocyclic yellow include pigment yellow 117 and pigment yellow 138. Examples of other suitable colored pigments are described in The Color Index, 3rd edition (The Society of Dyers and Colorists, 1982).

In addition, when using a pigment as a coloring agent, the said dye can also be used together for a complementary color, toning, etc.
The amount of the colorant is preferably about 10 to 200% by weight, particularly about 25 to 150% by weight, based on the weight of the polymer, in relation to the amount of the polymer.

  As the polymer that forms the polymer emulsion, for example, vinyl polymers, polyester polymers, polyurethane polymers, and the like can be used. Particularly preferably used polymers are vinyl polymers and polyester polymers, such as those disclosed in JP-A Nos. 2000-53897 and 2001-139849.

According to a preferred embodiment of the present invention, the average particle size of the polymer fine particles containing these coloring materials is most preferably 0.16 μm or less in the ink.
The content of the polymer fine particles in the ink is preferably about 8 to 20% by weight, more preferably about 8 to 12% by weight in terms of solid content.

  Regarding the wetting agent and the water-soluble organic solvent, the ink of the present invention uses water as a liquid medium. In order to make the ink have desired physical properties, to prevent the ink from drying, and to improve the dispersion stability. For the purpose of improving, for example, the following water-soluble organic solvents are used. A plurality of these water-soluble organic solvents may be used in combination.

Specific examples of the wetting agent and the water-soluble organic solvent include the following.
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, Polyhydric alcohols such as 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol;
Polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether;
Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;
Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;
Amides such as formamide, N-methylformamide, N, N-dimethylformamide;
Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine;
Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol;
Propylene carbonate, ethylene carbonate and the like.

  Among these organic solvents, diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5-pentane Diol, 2-pyrrolidone and N-methyl-2-pyrrolidone are preferred. These are excellent in solubility and prevention of poor jetting characteristics due to water evaporation.

  The other wetting agent preferably contains sugar. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides) and polysaccharides, preferably glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, Examples include lactose, sucrose, trehalose, and maltotriose. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose.

The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above (for example, sugar alcohol (general formula HOCH ₂ (CHOH) nCH ₂ OH (where n is an integer of 2 to 5)). ), Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Particularly preferred are sugar alcohols, and specific examples include maltitol, sorbit, and the like.
The content of these saccharides is suitably 0.1 to 40% by weight, preferably 0.5 to 30% by weight of the ink composition.

The ratio of pigment to wetting agent has a great influence on the stability of ink ejection from the head. If the pigment solid content is high but the amount of the wetting agent is small, water evaporation near the ink meniscus of the nozzle advances and discharge failure occurs.
The blending amount of the wetting agent is 10 to 50 wt%, and the polymer fine particles containing the coloring material are 8 wt% or more, preferably 8 to 20 wt%. Is from 0.5 to 6.25, more preferably from 2.0 to 6.0, and most preferably from 3.0 to 5.0. Ink within this range has very good drying, storage and reliability tests.

As the surfactant, an anionic surfactant or a nonionic surfactant is used. A surfactant that does not impair the dispersion stability is selected depending on the combination of the type of colorant, the wetting agent, and the water-soluble organic solvent.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate, and the like.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, and the like. Can be mentioned.

Acetylene glycol surfactants are 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl. An acetylene glycol type such as -1-hexyn-3-ol (for example, Surfynol 104, 82, 465, 485 or TG manufactured by Air Products (USA)) can be used, and particularly Surfinol 465, 104 and TG. Indicates good print quality.
The surfactants can be used alone or in combination of two or more.

  In the present invention, wettability to recording paper can be improved by using a surfactant. Preferred surfactants include interfacial polyoxyethylene alkyl ether acetates, dialkyl sulfosuccinates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polyoxypropylene block copolymers, and acetylene glycol surfactants. Agents. More specifically, examples of the anionic surfactant include polyoxyethylene alkyl ether acetate (I) and / or dialkylsulfosuccinic acid (II) having a branched alkyl chain having 5 to 7 carbon chains, By using these, the characteristics of plain paper are improved, and further the dissolution / dispersion stability of the colorant can be obtained.

Embedded image
_{R 1 -O- (CH 2 CH 2} O) mCH 2 COOM ...... (I)
(R ₁ : alkyl group having 6 to 14 carbon atoms which may be branched, m: 3 to 12, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

（Ｒ_２：炭素数５〜１６の分岐したアルキル基、Ｍ：アルカリ金属イオン、第４級アンモ
ニウム、第４級ホスホニウム、アルカノールアミン）
Embedded image

(R ₂ : branched alkyl group having 5 to 16 carbon atoms, M: alkali metal ion, quaternary ammonium, quaternary phosphonium, alkanolamine)

（Ｒは分岐しても良い６〜１４の炭素鎖、ｋ：５〜２０）

(R may be branched 6-14 carbon chain, k: 5-20)

Embedded image
_{R- (OCH 2 CH 2) nOH} ...... (IV)
(R is a carbon chain having 6 to 14 carbon atoms which may be branched, n: 5 to 20)

（Ｒ’は炭素数６〜１４の炭素鎖、ｍ≦２０、ｎ≦２０）
[Chemical 1]

(R ′ is a carbon chain having 6 to 14 carbon atoms, m ≦ 20, n ≦ 20)

（ｐ、ｑは０〜４０）

(P and q are 0 to 40)

  Further, by using lithium ions, quaternary ammonium and quaternary phosphonium represented by the following general formula as counter ions of the surfactant of the present invention, the surfactant exhibits excellent dissolution stability.

  Preferred nonionic surfactants include those represented by general formula (III) which is polyoxyethylene alkylphenyl ether and those represented by general formula (VI) which are acetylene glycol surfactants. By using these together, penetrability can be mentioned as a further synergistic effect, and this makes it possible to reduce ink at the color boundary and to obtain ink with less character bleeding.

Ink storage stability can be obtained by setting the pH of the ink to 6 or more, and many copy papers and sticky notes used in offices have a pH of 5-6. The ink is discharged from a fine discharge port of 9 to 60 μm and is ejected as a droplet having a weight of 3 ng to 50 ng at a rate of 5 to 20 m / s, and the adhesion amount in a single color is changed from 1.5 g / m ² to 30 g / m ^2. By recording on a so-called plain paper having a Steecht sizing degree of 3 seconds or more according to the JIS P-8122 test method, a recording method for forming a high-quality, high-resolution recorded image can be provided. However, when the pH is 9 or more, the active agent (II) is likely to change its physical properties due to decomposition during storage, and therefore the pH is preferably 6 to 9 when (II) is used.

The addition amount of (I), (II), (III), (IV), (V), (VI) that can be used in the present invention is required by the printer system between 0.05 to 10% by weight. It is possible to give the desired penetrability to the ink properties. Here, if it is 0.05% or less, bleeding occurs at the boundary between the two-color overlapping portions in any case, and if it is added in an amount of 10% by weight or more, the compound itself may easily precipitate at a low temperature, resulting in poor reliability.
Table 1 specifically shows the surfactants (I) and (II) used in the present invention in free acid form.

The surface tension in the present invention is an index indicating the permeability to paper. In particular, the surface tension indicates the dynamic surface tension in a short time of 1 second or less after the surface is formed, and is different from the static surface tension measured by the saturation time. . As a measuring method, any method can be used as long as it can measure a dynamic surface tension of 1 second or less by a conventionally known method described in JP-A-63-131237. In the present invention, a Wilhelmy type suspension plate type surface is used. Measurement was performed using a tensiometer. When the value of the surface tension is preferably 40 mJ / m ² or less, more preferably 35 mJ / m ² or less, excellent fixing properties and drying properties can be obtained.

The polyol or glycol ether having 8 to 11 carbon atoms used in the present invention is a partially water-soluble polyol and / or glycol having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. By adding 0.1 to 10.0% by weight of ether with respect to the total weight of the recording ink, the wettability of the ink to the heat element is improved, and even with a small amount of addition, the ejection stability and frequency stability are improved. It turns out that it is obtained.
(1) 2-ethyl-1,3-hexanediol Solubility: 4.2% (20 ° C.)
(2) 2,2,4-Trimethyl-1,3-pentanediol Solubility: 2.0% (25 ° C.)

  A penetrant having a solubility of less than 0.1-4.5% by weight in water at 25 ° C. has the advantage of very high permeability instead of low solubility. Therefore, a highly penetrating ink can be obtained by combining a penetrant having a solubility of less than 0.1 to 4.5% by weight in water at 25 ° C. with another solvent or another surfactant. It becomes possible to create.

Conventionally known additives can be added to the ink of the present invention in addition to the colorant, solvent, and surfactant.
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 antimicrobial agents.

As the pH adjuster, any substance can be used as long as the pH can be adjusted 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 carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.

  Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate, and the like.

Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
Depending on the purpose, a water-soluble ultraviolet absorber, a water-soluble infrared absorber, or the like can be added.

Next, the ink set of the present invention will be described.
The ink set is composed of black ink and color ink. As the color ink, a color ink containing a polymer emulsion containing the above color material is applied. The black ink corresponds to a configuration in which the polymer emulsion constituting the color ink is replaced with self-dispersing carbon black. That is, in an ink set for ink jet recording composed of black ink and at least one color ink, the black ink contains a self-dispersing pigment, and glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexane A polyol containing at least one wetting agent selected from diol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane, and having 8 to 11 carbon atoms Or an ink containing at least a glycol ether, an anionic or nonionic surfactant, a water-soluble organic solvent, water, and an ink viscosity at 25 ° C. of 5 mPa · sec or more, wherein the color ink is insoluble in the polymer fine particles. Contains a polymer emulsion containing a hardly soluble coloring material, glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene A polyol or glycol ether containing 8 or more and 11 or less carbon atoms, an anionic or nonionic surfactant, a water-soluble organic solvent containing at least one kind of wetting agent selected from glycol, trimethylolpropane, and trimethylolethane And an ink set for ink-jet recording, which contains at least water and has an ink viscosity at 25 ° C. of 5 mPa · sec or more.

Black ink is (1) self-dispersing carbon black (2) wetting agent 1 (glycerin)
(3) Wetting agent 2 (selected from 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane At least one type)
(4) Water-soluble organic solvent (5) Anion or nonionic surfactant (6) Polyol or glycol ether having 8 to 11 carbon atoms (7) Emulsion (8) Preservative (9) pH adjuster (10) Pure water

  As the coloring material, a self-dispersing color pigment that can be stably dispersed without using a dispersant in which at least one hydrophilic group is bonded to the surface of carbon black directly or via another atomic group is used. As a result, unlike the conventional ink, a dispersing agent for dispersing the carbon black becomes unnecessary. As the self-dispersing carbon black used in the present invention, those having ionicity are preferable, and those having an anionic charge or those having a cationic charge are suitable.

Examples of the anionic hydrophilic group, for _{example, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR ( where, M in the formula is a hydrogen atom, R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. It is done. In the present invention, among these, it is particularly preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment.

  “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as the alkali metal, and examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium. Is mentioned. As a method for obtaining an anionically charged color pigment, for example, -COONa is introduced into the surface of the color pigment, for example, a method in which the color pigment is oxidized with sodium hypochlorite, a method by sulfonation, or a reaction with a diazonium salt. Of course, the present invention is not limited to these methods.

  As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and more preferable examples include quaternary ammonium groups listed below. In the present invention, any of these is bonded to the carbon black surface. Are preferably used as the coloring material.

  As a method for producing a cationic self-dispersing carbon black having a hydrophilic group as described above, for example, as a method for bonding an N-ethylpyridyl group having the structure shown below, Although the method of processing with -N-ethyl pyridium bromide is mentioned, of course, this invention is not limited to this.

In the present invention, the hydrophilic group as described above may be bonded to the surface of carbon black via another atomic group. Examples of other atomic groups include an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or a naphthyl group which may have a substituent. Specific examples of the hydrophilic group described above is bonded to the surface of carbon black via other atomic group, for _{example, -C 2 H 4 COOM, -PhSO} 3 M, -C 5 H 10 NH 3 + , etc. Of course, the present invention is not limited to these.

The self-dispersing carbon black used for the black ink of the ink set of the present invention is cationically or anionicly charged by the hydrophilic group on the surface of the carbon black, has water dispersibility due to repulsion of the ions, The hydrophilic group is also improved by the hydrophilic group. Therefore, an aqueous pigment ink that is stably dispersed in an aqueous medium can be obtained without increasing the particle size or viscosity of the pigment even when left for a long period of time. When the polarity of the black ink is opposite to the polarity of the color ink constituting the ink set, an image with the least blurring of the color boundary is obtained, but the ink set of the present invention has a high viscosity and low surface tension permeability. Even if the color ink and the black ink have the same polarity, even if the color ink and the black ink have the same polarity, there is very little blurring of the color boundary, and even if the ink is mixed on the nozzle maintenance mechanism or the nozzle plate, An ink set excellent in handleability can be obtained without causing aggregation and thickening.
As other constituent materials used for the black ink of the ink set, the materials described in the ink containing polymer fine particles containing a colorant can be applied as they are.

A resin emulsion is preferably used only for black ink.
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 in the dispersed phase include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins.

  According to a preferred embodiment of the present invention, the resin is preferably a polymer having both a hydrophilic part and a hydrophobic part. The particle size of these resin components is not particularly limited as long as an emulsion is formed, 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 in water, optionally with a surfactant.
For example, an acrylic resin or styrene-acrylic resin emulsion can be obtained 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 preferably about 10: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when it exceeds the above range, the water resistance of the ink tends to be lowered or the penetrability tends to deteriorate.
The ratio of the resin as the dispersed phase component of the emulsion and water is 60 to 400 parts by weight, preferably 100 to 200 parts by weight with respect to 100 parts by weight of the resin.

  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 & Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.) Etc.).

The ink used in the present invention preferably contains a resin emulsion such that the resin component is 0.1 to 40% by weight of the ink, more preferably 1 to 25% by weight.
The resin emulsion has the property of thickening and aggregating, has the effect of suppressing the penetration of the coloring components, 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, and the printed material has an effect of improving the abrasion resistance.

  The recording liquid cartridge containing the recording liquid of the present invention and the ink jet recording apparatus including the recording liquid cartridge will be described with reference to the drawings. However, the following is only one example of the configuration, and the present invention is not limited in any way. is not.

FIG. 1 is a schematic front view of a mechanism part of a serial type ink jet recording apparatus equipped with an ink cartridge having a recording liquid storage part storing a recording liquid of the present invention.
The mechanism part of this ink jet recording apparatus lays a main support guide rod (3) and a sub support guide rod (4) between side plates (1) and (2) on both sides in a substantially horizontal positional relationship, The carriage unit (5) is slidably supported in the main scanning direction by the support guide rod (3) and the secondary support guide rod (4). The carriage unit (5) has four heads (6) for ejecting yellow (Y) ink, magenta (M) ink, cyan (C) ink and black (Bk) ink, respectively, and their ejection surfaces (nozzles). The surface (6a) is mounted facing downward, and on the upper side of the head (6) of the carriage unit (5) is an ink supply body of each color for supplying ink to each of the four heads (6). Four ink cartridges (7y), (7m), (7c), and (7k) are mounted interchangeably.
The carriage unit (5) is a timing belt (11) stretched between a drive pulley (drive timing pulley) (9) and a driven pulley (idler pulley) (10) rotated by the main scanning motor (8). The carriage (5), that is, the four heads (6) are moved in the main scanning direction by driving and controlling the main scanning motor (8).

  Further, subframes (13) and (14) are erected on the bottom plate (12) connecting the side plates (1) and (2), and the paper (16) is mainly placed between the subframes (13) and (14). A conveyance roller (15) for feeding in the sub-scanning direction orthogonal to the scanning direction is rotatably held. A sub-scanning motor (17) is disposed on the side of the sub-frame (14), and the rotation of the sub-scanning motor (17) is transmitted to transmit the rotation of the sub-scanning motor (17) to the transport roller (15). A gear (18) fixed to the shaft and a gear (19) fixed to the shaft of the conveying roller (15) are provided.

  Further, between the side plate (1) and the subframe (12), a reliability maintenance / recovery mechanism (hereinafter referred to as “subsystem”) (21) of the head (6) is disposed. The sub-system (21) holds four cap means (22) for capping the ejection surface of each head (6) by a holder (23), and the holder (23) can be swung by a link member (24). The carriage unit (5) is brought into contact with the engaging portion (25) provided in the holder (23) by the movement of the carriage unit (5) in the main scanning direction, so that the carriage unit (5) moves according to the movement of the carriage unit (5). The holder (23) is lifted up, the cap means (22) is used to capping the ejection surface (6a) of the ink jet head (6), and the carriage unit (5) is moved to the printing area side, whereby the carriage unit (5 ), The holder (23) is lifted down so that 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), and forms an atmosphere opening, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. ing. The suction pump (27) discharges the sucked waste liquid to a waste liquid storage tank (not shown) through a drain tube or the like. Further, on the side of the holder (23), there is a wiper blade (28) which is a wiping means made of an elastic member such as a fiber member, a foam member or rubber for wiping the discharge surface (6a) of the inkjet head (6). The blade arm (29) is attached to an arm (29) and is pivotally supported so as to be swung by rotation of a cam 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 into the recording apparatus, and FIG. 3 is a front sectional view of the ink cartridge.
As shown in FIG. 3, the ink cartridge (7) includes an ink absorber (42) that absorbs ink of a required color in a cartridge body (41). The cartridge body (41) is formed by adhering or welding an upper lid member (44) to an upper opening of a case (43) having a wide opening at the upper portion, 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, and after being compressed and inserted into the cartridge body (41), the ink is absorbed.
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 (45) is formed on the inner peripheral surface of the ink supply port (45). 46). The upper lid member (44) has an air opening (47).
The cartridge main body (41) is closed with the ink supply port (45) in a state before being loaded, and the case (43) with pressure applied to the wide side wall during handling of the cartridge during loading or transportation, or during vacuum packaging. ) Is compressed and deformed, and the cap member (50) is attached to prevent the internal ink from leaking.

Further, as shown in FIG. 2, the air opening (47) is sealed by attaching a film-like sealing member (55) having an oxygen permeability of 100 ml / m ² or more to the upper lid member (44). The sealing member (55) is sized to seal the plurality of grooves (48) formed around it together with the atmosphere opening (47). In this way, the air opening (47) is sealed with the sealing member (55) having an oxygen permeability of 100 ml / m ² or more, so that the ink cartridge (7) is made of a packaging member such as a non-permeable aluminum laminate film. By wrapping in a reduced pressure state, gas is contained in the ink due to the atmosphere in the space (A) (see FIG. 3) that is formed between the ink absorber (42) and the cartridge body (41) when the ink is filled. Even when dissolved, the air in the ink is discharged to the space between the packaging member outside the cartridge body (41) having a high degree of vacuum through the seal member (55), and the degree of deaeration of the ink is improved.

FIG. 4 shows an example of the configuration of a recording cartridge provided with a recording liquid storage unit that stores the recording liquid of the present invention and a head unit for discharging recording droplets.
That is, the recording unit (30) is of a serial type, and includes an ink jet head (6), an ink tank (41) that stores a recording liquid supplied to the ink jet head (6), and the ink tank (41). ) The main part is composed of a lid member that seals the inside. The inkjet head (6) is formed with a large number of nozzles (32) for discharging recording liquid. The recording liquid is guided from the ink tank (41) to a common liquid chamber (not shown) via an ink supply pipe (not shown), and the nozzles according to an electrical signal from the recording apparatus main body input from the electrode (31). (32). This type of recording unit has a structure suitable for a head of a type that can be manufactured at low cost, a head called a thermal method or a bubble method, which uses thermal energy as a driving power source. Recording liquid of the present invention, there is provided a recording method such as bubble or thermal system, by adding a polyol or glycol ether of C ₈ -C _11, since the wettability to thermal elements is improved even at low dosages Discharge stability and frequency stability are obtained, and safety is high, which is very suitable.

Here, the serial type ink jet recording apparatus as described above has been described, but the recording liquid of the present invention has the same or a fraction of the density as the target image resolution with an arbitrary arrangement of nozzles such as a staggered pattern. It is also possible to apply the present invention to a recording apparatus having a so-called line head that is integrated and arranged beyond the width of the recording medium.
In addition, the recording apparatus here may be an apparatus having a complex function in combination with a fax machine, a scanner, a telephone, or the like as well as a PC or a digital camera output printer.

Reference Example 1 Preparation of Dispersion of Phthalocyanine Pigment-Containing Polymer Fine Particle A blue polymer fine particle dispersion was obtained by reexamining Preparation Example 3 described in JP-A No. 2001-139849.
The average particle diameter (D50%) of the fine polymer particles measured by Microtrac UPA was 93 nm.

Reference Example 2 Preparation of Dimethylquinacridone Pigment-Containing Polymer Fine Particle Dispersion A red-purple polymer fine particle dispersion was obtained in the same manner as in Reference Example 1, except that the phthalocyanine pigment of Reference Example 1 was changed to Pigment Red 122. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 127 nm.

Reference Example 3 Preparation of Monoazo Yellow Pigment-Containing Polymer Fine Particle Dispersion A yellow polymer fine particle dispersion was obtained in the same manner as in Reference Example 1 except that the phthalocyanine pigment of Reference Example 1 was changed to Pigment Yellow 74. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 76 nm.

Reference Example 4 Preparation of Carbon Black-Containing Polymer Fine Particle Dispersion A black polymer fine particle dispersion was obtained in the same manner as in Reference Example 1, except that the phthalocyanine pigment of Reference Example 1 was changed to carbon black (Degussa FW100). The average particle size (D50%) of the polymer fine particles measured by Microtrac UPA was 104 nm.

Reference Example 5 Carbon black dispersion 1 treated with a diazo compound
100 g of carbon black having a surface area of 230 m ² / g and a DBP oil absorption of 70 ml / 100 g and 34 g of p-amino-N-benzoic acid are mixed and dispersed in 750 g of water, and 16 g of nitric acid is added dropwise thereto and stirred at 70 ° C. did. After 5 minutes, a solution of 11 g of sodium nitrite dissolved in 50 g of water was added, and the mixture was further stirred for 1 hour. The resulting slurry was diluted 10 times and centrifuged to remove coarse particles, the pH was adjusted with diethanolamine to pH 8-9, desalted and concentrated with an ultrafiltration membrane, and a carbon black dispersion having a pigment concentration of 15% did. This was made into carbon black dispersion 1 with a polypropylene 0.5 μm filter. The average particle size (D50%) measured by Microtrac UPA was 99 nm.

<Reference Example 6> Carbon black dispersion 2 treated with hypochlorous acid
After mixing 300 g of commercially available acidic carbon black having a pH of 2.5 (trade name Monarch 1300, manufactured by Cabot Corporation) with 1000 ml of water, 450 g of sodium hypochlorite (effective chlorine concentration: 12%) was dropped, and 100 to 105 Stir at 8 ° C. for 8 hours. To this solution, 100 g of sodium hypochlorite (effective chlorine concentration 12%) was further added and dispersed for 3 hours with a horizontal disperser. The obtained slurry was diluted 10 times with water, pH was adjusted with lithium hydroxide, desalted and concentrated with an ultrafiltration membrane to an electric conductivity of 0.2 mS / cm, and a carbon black dispersion with a pigment concentration of 15% was obtained. A liquid was used. Coarse particles were removed by centrifugation and further filtered through a 1 micron nylon filter to obtain a carbon black dispersion 2. The average particle size (D50%) measured by Microtrac UPA was 95 nm.

Reference Example 7 Carbon black dispersion 3 treated with sulfonating agent
150 g of a commercially available carbon black pigment (“Printex # 85” manufactured by Degussa) was mixed well in 400 ml of sulfolane, finely dispersed with a bead mill, 15 g of amidosulfuric acid was added, and the mixture was stirred at 140 to 150 ° C. for 10 hours. The obtained slurry is put into 1000 ml of ion-exchanged water, and a surface-treated carbon black wet cake is obtained by a centrifuge at 12000 rpm. This carbon black wet cake was redispersed in 2000 ml of ion exchange water, pH was adjusted with lithium hydroxide, and desalted and concentrated with an ultrafiltration membrane to obtain a carbon black dispersion having a pigment concentration of 10% by weight. This was filtered through a 1 micron nylon filter to obtain a carbon black solution 3. The average particle size was 80 nm.

Reference Example 8 Diazo compound-treated carbon black dispersion 4 (cationic)
Carbon black dispersion 4 was prepared using N- (4-aminophenyl) pyridinium chloride in place of p-amino-N-benzoic acid in Reference Example 5.

Examples and Comparative Examples of the present invention are shown below, but the present invention is not limited to these. In addition, the amount (%) of each component described in the examples is based on weight.
< Reference Example 11 >
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition.
Polymer fine particles containing phthalocyanine pigment of Reference Example 1 8.0 wt%
(As solids)
Triethylene glycol 22.5wt%
Glycerol 7.5wt%
2-pyrrolidone 5.0wt%
Activator of specific example (I-1) described in Table 1 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 12 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Polymer fine particles containing dimethylquinacridone pigment of Reference Example 8.0 wt%
(As solids)
Propylene glycol 30.0wt%
Glycerol 10.0wt%
N-methyl-2-pyrrolidone 2.0wt%
Activator of specific example (I-2) described in Table 1 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 13 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Monoazo yellow pigment-containing polymer fine particles of Reference Example 8.0 wt%
(As solids)
1,3-butanediol 22.5 wt%
Glycerol 7.5wt%
2-pyrrolidone 5.0wt%
Activator of specific example (I-4) described in Table 1 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 14 >
Black pigment ink An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Carbon black-containing polymer fine particles of Reference Example 8.0 wt%
(As solids)
Dipropylene glycol 20.0wt%
Glycerol 10.0wt%
N-hydroxyethyl-2-pyrrolidone 5.0wt%
Activator of specific example (I-3) described in Table 1 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 15 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
12.0 wt% of phthalocyanine pigment-containing polymer fine particles of Reference Example 1
(As solids)
2,3-butanediol 22.5 wt%
Glycerol 7.5wt%
N-methyl-2-pyrrolidone 3.0wt%
Activator of specific example (I-5) described in Table 1 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 16 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Dimethylquinacridone pigment-containing polymer fine particle of Reference Example 1 12.0 wt% (as solid content)
Dipropylene glycol 15.0wt%
Glycerol 15.0wt%
N-hydroxyethyl-2-pyrrolidone 5.0wt%
Activator of specific example (I-6) described in Table 1 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 1 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Polymer fine particles containing monoazo yellow pigment of Reference Example 1 12.0 wt%
(As solids)
1,3-propanediol 22.5 wt%
Glycerol 7.5wt%
2-pyrrolidone 5.0wt%
Activator of specific example (II-1) described in Table 1 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 2 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Carbon black dispersion 1 treated with diazo compound of Reference Example 5 8.0 wt% (as solid content)
1,4-butanediol 22.5 wt%
Glycerol 7.5wt%
N-methyl-2-pyrrolidone 2.0wt%
Activator of specific example (II-2) described in Table 1 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 3 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
15.0 wt% of phthalocyanine pigment-containing polymer fine particles of Reference Example 1
(As solids)
1,5-pentanediol 15.0 wt%
Glycerol 15.0wt%
N-hydroxyethyl-2-pyrrolidone 2.0wt%
Activator of specific example (II-3) 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 4 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Dimethylquinacridone pigment-containing polymer fine particles of Reference Example 1 15.0 wt% (as solid content)
1,6-hexanediol 22.5 wt%
Glycerol 7.5wt%
2-pyrrolidone 3.0wt%
Activator of specific example (II-4) 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 17 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Polymer fine particles containing monoazo yellow pigment of Reference Example 1 15.0 wt%
(As solids)
2-methyl-2,4-pentanediol 22.5 wt%
Glycerol 7.5wt%
N-methyl-2-pyrrolidone 5.0wt%
Activator of general formula (III) (R = C6, k = 5) 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 5 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Carbon black dispersion 2 treated with hypochlorous acid in Reference Example 2 10.0 wt%
1,2,6-hexanetriol 30.0wt%
Glycerol 10.0wt%
N-hydroxyethyl-2-pyrrolidone 5.0wt%
Activator of general formula (IV) (R = C6, n = 5) 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Example 6 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Carbon black dispersion 3 treated with sulfonating agent of Reference Example 7 10.0 wt%
Trimethylolpropane 20.0wt%
Glycerol 20.0wt%
2-pyrrolidone 4.0wt%
Activator of general formula (V) (R ′ = 6, n = 2, m = 3) 2.0 wt%
2-ethyl-1,3-hexanediol 2.0wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

< Reference Example 18 >
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was changed to 9 with lithium hydroxide.
Carbon black dispersion 4 treated with the diazo compound of Reference Example 4 (cationic)
8.0wt%
Trimethylolethane 22.5wt%
Glycerol 7.5wt%
N-methyl-2-pyrrolidone 2.0wt%
Activator of general formula (VI) (mixture of p + q = 15, p + q = 0) 2.0 wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Comparative Example 1>
An ink composition having the following formulation was prepared and adjusted with a 10% aqueous solution of lithium hydroxide so that the pH was 9. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer, and obtained the ink composition.
Polymer fine particles containing phthalocyanine pigment of Reference Example 1 5.0 wt%
Ethylene glycol 15.0wt%
Glycerol 5.0wt%
2-pyrrolidone 2.0wt%
ECTD-3NEX
(Anionic surfactant manufactured by Nikko Chemicals) 1.0wt%
2-ethyl-1,3-hexanediol 2.0 Wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Comparative example 2>
An ink composition was prepared in the same manner as in Comparative Example 1, except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Polymer fine particles containing dimethylquinacridone pigment of Reference Example 6.0 wt%
Diethylene glycol 15.0wt%
Glycerol 5.0wt%
N-methyl-2-pyrrolidone 2.0wt%
ECTD-6NEX
(Anionic surfactant manufactured by Nikko Chemicals) 1.0wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Comparative Example 3>
An ink composition was prepared in the same manner as in Comparative Example 1, except that the following composition was used, and the pH was adjusted to 9 with lithium hydroxide.
Polymer fine particles containing monoazo yellow pigment of Reference Example 5.0 wt%
Triethylene glycol 15.0wt%
Glycerol 5.0wt%
N-hydroxyethyl-2-pyrrolidone 2.0wt%
Dispanol TOC
(Non Fatty Surfactant manufactured by NOF Corporation) 1.0wt%
2-ethyl-1,3-hexanediol 2.0wt%
Emulsion 3.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

<Comparative example 4>
An ink composition was prepared in the same manner as in Reference Example 11 except that the following composition was used, and the pH was adjusted to 9 with sodium hydroxide.
Carbon black dispersion 1 treated with the diazo compound of Reference Example 5
4.0 wt% (pigment solids)
Ethylene glycol 15.0wt%
Glycerol 5.0wt%
2-pyrrolidone 2.0wt%
ECTD-6NEX
(Anionic surfactant manufactured by Nikko Chemicals) 1.0wt%
2,2,4-Trimethyl-1,3-pentanediol 2.0wt%
Proxel LV (preservative) 0.2wt%
Ion exchange water

Table 3 shows the pigment concentration, wetting agent concentration, and ink viscosity of the ink compositions of Examples 1 to 6, Reference Examples 11 to 18, and Comparative Examples 1 to 4.

[Table 3]

Next, cyan in Table 3 for Examples 1 to 6, Reference Examples 11 to 18 and Comparative Examples 1 to 4,
Ink sets 1 to 5 consisting of magenta, yellow and black, and ink set comparison 1
The following tests were conducted.
Ink sets 4 and 5 were used by replacing the black ink of ink set 2.

1) Sharpness of image (1) Printing was performed on each of the following papers using an ink jet printer EM-900 (manufactured by Seiko Epson Corporation), changing the driving voltage, frequency, and pulse width of the head. As for the printing pattern, yellow, magenta, and cyan color pigment inks were printed at 100% duty, and black ink filled with the black ink of the present invention printed characters simultaneously. The printing conditions were Mj 35 pl, Vj 20 m / sec, frequency 1 kHz, recording density 360 dpi, and one-pass printing.
(2) Solid and characters were printed by one-pass printing under the same conditions as in (1) by changing the driving voltage, frequency and pulse width of the head of the Ricoh inkjet printer IPSiO Jet300.
After printing and drying, the blur at the boundary of the two-color overlapping portion, the image blur, the color tone, and the image density were comprehensively examined visually and by a reflective color spectrophotometric densitometer (manufactured by X-Rite), and judged according to the evaluation criteria. The printing test paper used is shown below.

(1) My paper (NBS Ricoh Co., Ltd.)
(2) Paper source S / Recycled paper (NBS Ricoh Co., Ltd.)
(3) PB paper (made by Canon Inc.)
(4) Multiace (Fuji Xerox Office Supply Co., Ltd.)
(5) Yamayuri paper (Honshu Paper Co., Ltd., recycled paper)
(6) LH paper (Fuji Xerox Office Supply Co., Ltd.)
(7) Xerox 4024 paper (Fuji Xerox Office Supply Co., Ltd.)
(8) Neenah Bond paper (made by Kimberly Clark)

Judgment criteria A: Clear printing without occurrence of bleeding on all papers.
○: Whisker-like bleeding occurs on some paper (recycled paper).
Δ: Whisker-like bleeding occurs on all papers.
X: The blur has occurred so that the outline of the character is not clear.

2) Image drying property 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 paper was dried within 10 seconds, it was judged as “good”.

3) Storage stability Each ink is put in a polyethylene container and stored at −20 ° C., 5 ° C., 20 ° C., and 70 ° C. for 3 months, and after storage, surface tension, viscosity, and the presence or absence of precipitation. I investigated. Even if it preserve | saved on what conditions, the thing which does not change a physical property etc. was set as (circle).

4) Reliability when printing is stopped Using the head of the Ricoh printer IPSIO Jet300, it is checked how much time (seconds) can be recovered even if printing is stopped without capping, cleaning, etc. during printer operation. Table 4 shows the results of evaluating the reliability according to whether the ejection direction is shifted or the weight of the ejected droplets is changed.

[Table 4]

Effect of the invention

As described above, as is clear from the detailed and specific description, the penetrating ink has so far been excellent in quick-drying and fixing properties, but has had problems in image quality such as feathering, reduction in print density, and color bleeding. According to the present invention, the polymer fine particles containing a colorant are 8 wt% or more in solids, glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, In an ink composition having a high viscosity of at least 5.0 cps, preferably 8.0 cps or more, containing at least one wetting agent selected from diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylolethane, Mj 5 to 35 pl, Vj 6 to 20 m / sec, frequency 1 KHz or more, resolution 300 dpi or more, and high-quality image quality comparable to that of a laser printer on plain paper. Furthermore, since the coloring material stays on the paper surface, the back-through is significantly reduced compared to the conventional case, and double-sided printing is possible (the back-through density: 0.02-0.04 / the conventional 0.15-0.2). ).
Further, due to the interaction between the polyol having 8 to 11 carbon atoms and the surfactants (I) to (VI), the surface tension of the ink is 40 dyn / cm or less, and the polymer fine particles are 8 wt% or more in solid content, 8 Even with a high viscosity of 0.0 cps or more, it quickly fixes to most recording materials and has sufficient marker resistance. In addition, the wetness to the head member was improved, and the ink composition bubble discharge performance was improved, the frequency response was improved, and the ejection stability was significantly improved.
The ink composition of the present invention is a high-viscosity ink with a high pigment concentration, but glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol. , Diethylene glycol, dipropylene glycol, trimethylol propane, trimethylol ethane at least one kind of wetting agent has the effect of nozzle clogging and stable printing compared to conventional high pigment and high viscosity inks It became.
The ink composition of the present invention is a high-viscosity ink with a high pigment concentration, but glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol. Due to the effect of at least one kind of wetting agent selected from diethylene glycol, dipropylene glycol, trimethylolpropane and trimethylolethane, the storage stability was remarkably improved as compared with conventional high pigment / high viscosity inks.
In addition, according to the ink set of the present invention, a combination of the color ink configured as described above and the black ink in which the color material is replaced with self-dispersing carbon black in the configuration described above is used for black / color. There was almost no blurring of the color boundary between them, and it was possible to achieve high quality image quality comparable to a laser printer.
In addition, according to the present invention, there is provided a recording liquid cartridge containing a recording liquid that has such high penetrability, high reliability, safety, and excellent image characteristics, and a recording apparatus including the cartridge. it can.

  1 is a schematic front view showing a configuration example of a serial type ink jet recording apparatus equipped with an ink cartridge containing a recording liquid to which the present invention is applied.   FIG. 3 is an external perspective view of the ink cartridge before being loaded into the recording apparatus of the present invention.   It is a front sectional view of the ink cartridge of the present invention.   1 is an external perspective view of a recording unit integrated with a recording head of the present invention.

DESCRIPTION OF SYMBOLS 1 Side plate 2 Side plate 3 Main support guide rod 4 Sub support guide rod 5 Carriage unit 6 Head 6a Discharge surface (nozzle surface)
7 ink cartridge 7y yellow ink cartridge 7m magenta ink cartridge 7c cyan ink cartridge 7k black ink cartridge 8 main scanning motor 9 drive pulley (drive timing pulley)
10 Driven pulley (idler pulley)
11 Timing belt 12 Bottom plate 13 Sub-frame 14 Sub-frame 15 Transport roller 16 Paper 17 Sub-scanning motor 18 Gear 19 Gear 21 Reliability maintenance / recovery mechanism (subsystem)
22 Cap means 23 Holder 24 Link member 25 Engagement part 26 Suction tube 27 Suction pump 28 Wiping means (wiper blade)
29 Blade Arm 30 Recording Unit 31 Electrode 32 Nozzle 41 Cartridge Main Body 42 Ink Absorber 43 Case 44 Top Cover Member 45 Ink Supply Port 46 Seal Ring 47 Air Opening Port 50 Cap Member 55 Film-like Seal Member 48 Groove A Space

Claims (29)

At least polymer emulsion, anionic or nonionic surfactant, wetting agent, charcoal
A polyol or glycol ether having a prime number of 8 or more and 11 or less, a water-soluble organic solvent, and
Ink for ink jet recording containing water, ink viscosity at 25 ° C. is 5 mP
a · s or more,
The polymer emulsion contains a water-insoluble or hardly soluble coloring material in polymer fine particles.
And
The surfactant is selected from surfactants of the following formulas (II-1) to (II-4) ,
[Chemical 1]

The wetting agent includes glycerin and lactams,
The polyol or glycol ether having 8 to 11 carbon atoms is 2-ethyl-1
, 3-hexanediol or 2,2,4-trimethyl-1,3-pentanediol
Jet recording ink, characterized in that that.
2. The ink for ink jet recording according to claim 1, wherein the polymer forming the polymer emulsion is a vinyl polymer or a polyester polymer.
The ink for inkjet recording according to claim 1 or 2, comprising 10 to 50% by weight of the wetting agent.
The ink for ink jet recording according to any one of claims 1 to 3, wherein the polymer emulsion containing the coloring material is contained in an amount of 8 to 20% by weight in terms of solid content.
The ink for inkjet recording according to any one of claims 1 to 4, wherein an average particle diameter of emulsion particles in the ink containing the polymer emulsion containing the colorant is 0.16 µm or less.
2-5 weight ratio of wetting agent to polymer emulsion solids (wetting agent / emulsion solids)
The inkjet recording ink according to claim 1, wherein the inkjet recording ink is an inkjet recording ink.
The ink for ink jet recording according to any one of claims 1 to 6, wherein the ink has a viscosity of 8 to 20 mPa · sec (25 ° C).
The ink for inkjet recording according to any one of claims 1 to 7 , comprising 0.1 to 5 wt% of an anionic or nonionic surfactant.
The ink for inkjet recording according to any one of claims 1 to 8 , wherein the surface tension is 35 dyne / cm or less.
The said lactam consists of at least 1 sort (s) chosen from 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, and epsilon caprolactam , Any one of Claim 1 thru | or 9 characterized by the above-mentioned. the ink-jet recording ink according to either.
In an ink set for ink jet recording consisting of black ink and at least one color ink,
The black ink is a self-dispersing pigment, a wetting agent, a polyester having 8 to 11 carbon atoms.
Or glycol ether, anionic or nonionic surfactant, water-soluble organic solvent,
And an ink containing water and having an ink viscosity at 25 ° C. of 5 mPa · sec or more,
The color ink is composed of a polymer emulsion, a wetting agent, a poly-carbon having 8 to 11 carbon atoms.
All or glycol ether, anionic or nonionic surfactant, water-soluble organic solution
An ink containing an agent and water and having an ink viscosity at 25 ° C. of 5 mPa · sec or more.
The
The color ink polymer emulsion is insoluble or sparingly soluble in polymer particles.
The color material is included,
The black ink and the color ink wetting agent include glycerin and lactams,
A polyol having 8 to 11 carbon atoms in the black ink and the color ink;
Glycol ether is 2-ethyl-1,3-hexanediol or 2,2,4-toluene
Limethyl-1,3-pentanediol,
The surfactant of the black ink is selected from the following formulas (II-1) to (II-4)
And
The surfactant of the color ink was selected from the following general formulas (IV) and (V).
An ink set for ink-jet recording, characterized by being a thing.
[Chemical 2]

[Chemical Formula 3]

(R is a carbon chain having 6 to 14 carbon atoms which may be branched, n: 5 to 20)
[Formula 4]

(R ′ is a carbon chain having 6 to 14 carbon atoms, m ≦ 20, n ≦ 20)
The ink set for ink-jet recording according to claim 11 , comprising 10 to 50% by weight of the wetting agent.
The ink set for ink-jet recording according to claim 11 or 12 , wherein the pigment or polymer emulsion contains 8 to 20% by weight in solid content.
Self-dispersion pigment is a carboxyl group on the surface, a sulfone group, claims 11 to 1, characterized by having at least one hydrophilic group selected from a carbonyl group or a hydroxyl group,
4. An ink set for ink jet recording according to any one of 3 above.
Self-dispersion pigment is a carboxyl group through another atomic group to the surface, a sulfone group, any of claims 11 to 13, characterized by having at least one hydrophilic group selected from a carbonyl group or a hydroxyl group, An ink set for ink-jet recording according to claim 1.
The ink set for inkjet recording according to any one of claims 11 to 15 , wherein an average particle diameter of the contained particles is 0.16 µm or less.
11.乃 the viscosity of the ink is characterized in that it is a 8~20mPa · sec (25 ℃)
An ink set for ink jet recording according to any one of claims 16 to 16 .
The ink set for ink-jet recording according to any one of claims 11 to 17 , comprising 0.1 to 5 wt% of an anionic or nonionic surfactant.
The ink set for inkjet recording according to any one of claims 11 to 18 , wherein the surface tension is 35 dyne / cm or less.
The ink for inkjet recording according to any one of claims 1 to 10 , or the claims 11 to 11.
20. An ink jet recording method comprising discharging ink by applying energy to the ink set for ink jet recording according to any one of items 19 .
21. The ink jet recording method according to claim 20 , wherein the ink is ejected by applying thermal energy to the ink.
Claim, characterized in that ejects ink by applying mechanical energy to the ink 20
The ink jet recording method described in 1.
The ink for ink-jet recording according to any one of claims 1 to 10 or any one of claims 11 to 19 under one-pass printing conditions where Mj is 5 to 35 pl, Vj is 6 to 20 m, frequency is 1 KHz or more, resolution is 300 dpi or more. 23. The ink jet recording method according to claim 20 , wherein the ink set for ink jet recording is used.
The ink for inkjet recording according to any one of claims 1 to 10 , or the claims 11 to 11.
An ink cartridge comprising an ink storage portion that stores the ink set for inkjet recording according to any one of 19 .
The ink for inkjet recording according to any one of claims 1 to 10 , or the claims 11 to 11.
An ink jet recording comprising: an ink containing portion or an ink cartridge containing the ink set for ink jet recording according to any one of 19 ; and a head portion or a recording unit for dropping the ink by an action of energy to discharge the ink. apparatus.
26. The recording apparatus according to claim 25 , wherein an ink-repellent coating layer is formed on the surface of the nozzle plate of the inkjet recording head by eutectoid plating.
Claim 2 nozzle diameter of the inkjet recording head is equal to or less than 30μ
6. The recording device according to 6 .
24. A recorded matter recorded by the recording method according to claim 20 .
At least polymer emulsion, anionic or nonionic surfactant, wetting agent, charcoal
A polyol or glycol ether having a prime number of 8 or more and 11 or less, a water-soluble organic solvent, and
A method for producing an ink for ink jet recording in which water is mixed, the ink viscosity at 25 ° C.
The degree is 5 mPa · s or more,
The polymer emulsion contains a water-insoluble or hardly soluble coloring material in polymer fine particles.
And
The surfactant is selected from surfactants of the following formulas (II-1) to (II-4) ,
[Chemical formula 5]

The wetting agent includes glycerin and lactams,
The polyol or glycol ether having 8 to 11 carbon atoms is 2-ethyl-1
, 3-hexanediol or 2,2,4-trimethyl-1,3-pentanediol
Method for manufacturing an ink jet recording ink, characterized in that that.

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