JPH05148442A - Quick drying ink and recording method - Google Patents

Abstract

PURPOSE:To obtain the subject product capable of providing color image having quick dryness and high quality and excellent in storage stability and water resistance by adding a specific high polymer gel fine globe to water-dispersible or watersoluble coloring material, water and a wetting agent in shrunk state. CONSTITUTION:The objective product contains (A) a coloring material dispersible or soluble in water, (B) water and (C) a wetting agent (e.g. ethanol or polyethylene glycol) and further contains (D) a high polymer gel fine globe capable of changing volume by change of proton concentration in shrunk state. The component D is obtained by polymerizing, e.g. a system consisting of a cationic monomer such as diethylaminomethacrylate and a cross-linking agent such as N, N'-methylenebisacrylamide, water and a wetting agent with light. Furthermore, pH of the product is preferably set to 6-7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printout device for an office word processor, a personal computer or the like, and relates to an ink compatible with plain paper for ink jet which utilizes a viscosity change due to a volume change of a polymer gel and a recording method thereof.

[0002]

2. Description of the Related Art In recent years, there have been proposed a recording method utilizing a volume change due to a stimulus response of a polymer gel and a recording method utilizing a sol-gel change of a polymer gel. For example, Japanese Patent Application Laid-Open No. 62-60690 proposes a recording method utilizing absorption and discharge of a recording agent due to volume change due to electric field response. Further, a recording method utilizing a volume change due to thermal response is described in JP-A-63-7949. However, there has been no attempt to utilize this volume change in an inkjet ink. Further, in recent years, a bubble jet method has become mainstream as an inkjet method, and a high-quality monochrome printer using a water-based ink compatible with plain paper has been developed and announced in the December 1988 issue of HP Journal. However, this ink has a slow drying speed and is difficult to be colored. As a quick-drying ink, a low surface tension can be obtained by adding a specific surfactant to the ink as described in JP-A-55-29546, and JP-A-5-29546.
No. 6,578,62 discloses an ink to which a strongly basic substance is added. However, the former is effective but causes bleeding, and the latter is effective with rosin-sized paper, but not with alkyl ketene dimer sizing agents. Also, overprinting has no effect.

[0003]

[Object] The present invention relates to an inkjet ink, and an object thereof is to provide a quick-drying ink for plain paper, particularly a color ink, and a recording method using the same.

[0004]

[First Structure] The first aspect of the present invention is an ink jet recording ink utilizing the volume phase transition of a polymer gel, which has recently attracted attention from MIT's Tanaka et al.
The ink is adjusted to the alkaline side proton concentration in the recording head and in the storage state, and at the moment when it adheres to the recording paper, the proton concentration is changed to the acidic side by the proton donation from the recording paper, and the polymer gel microspheres swell, As a result, they have found that the viscosity of the ink increases and the effect of preventing bleeding appears, and the present invention has been completed. That is, the present invention is characterized in that an aqueous ink having a colorant that dissolves or disperses in water, water and a wetting agent contains polymer gel fine particles whose volume changes with a change in proton concentration. Regarding dry ink.

The range of the proton concentration of the ink is not particularly limited as long as it is on the alkaline side of the proton concentration of the recording paper, but the pH of the recording paper is generally 5 to 6 and therefore high. In order to perform the phase transition of the molecular gel microspheres, the pH of the ink is preferably set to 6-7.

Examples of the monomer or cross-linking agent for obtaining the polymer gel used in the present invention include the following. Preferred as the cation type monomer that induces the phase change of the present invention is

[Chemical 1] And so on. As the monomers used together with these, the following monomers can be used as long as they do not inhibit the phase change.

[Chemical 2]

[Chemical 3] As the crosslinkable monomer, N, N'-methylenebisacrylamide, ethylene glycol dimethacrylate, glycerin triacrylate, divinylbenzene or the like can be used.

Examples of the initiator for the polymerization include ammonium sulfate-sodium hydrogensulfate and hydrogen peroxide-ferrous iron salt in a water-soluble system. In the non-aqueous solvent, azoisobutyl nitrile, cumene hydroperoxide, azobiscyclohexanecarbonitrile, etc. may be mentioned.

The content of the fine particles of these polymer gels in the ink depends on the volume change rate of the particles and their size.
It is used within the range of 0.01 to 10% by weight.
The particle size is preferably from 0.1 micron to 1 micron.

The polymer gel used in the present invention which changes in volume due to a change in the proton concentration, has a rapid release of the wetting agent contained in the polymer gel fine particles under a specific pH condition when the pH condition is changed, that is, It is only necessary that the gel can be contracted and the wetting agent can be rapidly absorbed, that is, the gel can be swollen. Such polymer gels are known, and conventionally known synthesis methods such as emulsion polymerization method, reverse phase suspension polymerization method and precipitation polymerization method can be adopted. For example, a method of photopolymerizing a system consisting of a monomer, a crosslinking agent, water and a wetting agent can be mentioned. Furthermore, a surfactant is added to enhance the penetrability of the ink into paper and obtain sufficient drying property,
It is preferable to reduce the surface tension of the ink. The preferable surface tension of the ink varies depending on the type of recording paper, but as a method for measuring the surface tension, Wilhelmy is usually used.
The surface tension was measured using a lifting plate type surface tension measuring device.

As the surfactant, cationic, anionic, nonionic or amphoteric surfactants are used. These may be used alone or in combination of two or more. Particularly effective even with a small amount of fluorine-based surfactant,
This is preferable because clogging of the inkjet nozzle hardly occurs.
Further, the addition of polyhydric alcohol alkyl ether such as diethylene glycol monobutyl ether other than the activator can also adjust the dynamic surface tension to enhance the drying. The ink of the present invention comprises, in addition to polymer gel microparticles, a dye or pigment as a colorant and water or an organic solvent in which these are dispersed. In the case of water, a wetting agent is added for the purpose of preventing aggregation of dispersed fine particles and coloring material due to evaporation of water.

Examples of the wetting agent used in the recording material of the present invention include the following water-soluble organic compounds. Monohydric alcohols such as ethanol, methanol and propanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, glycerin, low molecular weight polyethylene glycol and hexylene glycol Alcohols: ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, propylene glycol mono ethyl Ethers and other polyhydric alcohol alkyl ethers, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether and other polyhydric alcohol aryl ethers; N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam , Nitrogen-containing heterocyclic compounds such as γ-butyrolactone;
Amides such as formamide, N-methylformamide, N, N-dimethylformamide; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide and sulfolane, Examples include propylene carbonate and ethylene carbonate. These solvents may be used alone or in combination with water.

As the water-soluble dye used as a coloring material, those which are classified into acid dyes, direct dyes, basic dyes, reactive dyes and food dyes in the color index and which have excellent water resistance and light resistance are used. Be done. Specific examples of these dyes include C.I. I. Acid. Yellow 17,23,42,
44, 79, 142 C.I. I. Acid. Red 1,8,13,1
4, 18, 26, 27, 35, 37, 42, 52, 8
2,87,89,92,97,106,111,11
4,115,134,186,249,254,289 C.I. I. Acid. Blue 9, 29, 45, 9
2,249 C.I. I. Acid. Black 1, 2, 7, 24,
26, 94 C.I. I. hood. Yellow 3,4 C.I. I. hood. Red 7,9,14 C.I. I. hood. Black 2 C.I. I. direct. Yellow 1,12,24,2
6,33,44,50,142,144,86 C.I. I. direct. Red 1, 4, 9, 13,
17, 20, 28, 31, 39, 80, 81, 83, 8
9,225,227 C.I. I. direct. Orange 26, 29, 62,
102 C. I. direct. Blue 1, 2, 6, 15,
22, 25, 71, 76, 79, 86, 87, 90, 9
8, 163, 165, 199, 202 C.I. I. direct. Black 19, 22, 32,
38, 51, 56, 71, 74, 75, 77, 154
168 C.I. I. basic. Yellow 1,2,11,1
3,14,15,19,21,23,24,25,2
8, 29, 32, 36, 40, 41, 45, 49, 5
1, 53, 63, 65, 67, 70, 73, 77, 8
7,91 C.I. I. basic. Red 2,12,13,1
4,15,18,22,23,24,27,29,3
5,36,38,39,46,49,51,52,5
4,59,68,69,70,73,78,82,10
2, 104, 109, 112 C.I. I. Basic Blue 1, 3, 5, 7,
9, 21, 22, 26, 35, 41, 45, 47, 5
4,62,65,66,67,69,75,77,7
8, 89, 92, 93, 105, 117, 120, 12
2,124,129,137,141,147,155 C.I. I. basic. Black 2,8 etc. can be used. As the pigment, as an organic pigment, an azo type, a phthalocyanine type, an anthraquinone type, a quinacridone type, a dioxazine type, an indigo type, a thioindigo type,
Perylene-based, isoindolenone-based, aniline black,
Examples thereof include azomethine type and carbon black, and examples of inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, dark blue, cadmium red, chrome yellow, and metal powder.

As the pigment dispersant, a hydrophilic polymer,
In the natural system, gum arabic, tragum gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch and other plant macromolecules, alginic acid, carrageenan, agar and other seaweed macromolecules, gelatin, casein, albumin. , Animal-based polymers such as collagen, microbial-based polymers such as xanthene gum and dextran, and fibrin-based polymers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and carboxymethyl cellulose in semi-synthetic systems, sodium starch glycolate ,
Starch-based polymers such as sodium starch phosphate, seaweed-based polymers such as sodium alginate, propylene glycol alginate, etc., vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyvinylmethyl ether, etc. in pure synthetic systems, non-crosslinked Polyacrylamide, polyacrylic acid and its alkali metal salts, acrylic resins such as water-soluble styrene acrylic resin, water-soluble styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic acid resin, polyvinyl alcohol, β- Examples thereof include alkali metal salts of formalin condensates of naphthalene sulfonic acid, polymer compounds having a side chain of a salt of a cationic functional group such as quaternary ammonium or amino group, and natural polymer compounds such as shellac.
In addition to the above-mentioned additives, other desired additives such as a pH adjusting agent and an antiseptic / antifungal agent can be added if necessary. The recording paper referred to in the present invention is not particularly limited in its kind as long as it is a material to which the quick-drying ink of the present invention can be applied.
Sheets etc. can also be used.

[0014]

【Example】

Example 1 Preparation of Proton-Responsive Gel Fine Particles Gel fine particles 1 obtained by cross-linking diethylaminomethacrylate with N, N-methylenebisacrylamide were obtained by the method of Kosuge et al. A color ink was obtained with the following formulation using the polymer gel particles. [Black ink 1] Surface tension: 39 dyn / cm C.I. I. Direct black 168 2% by weight Gel fine particles 1 0.1% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining [yellow ink 1] Surface tension: 39 dyn / cm C.I. I. Direct Yellow 86 2% by weight Gel particles 1 0.1% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining amount [Magenta ink 1] Surface tension: 39 dyn / cm Direct Red 227 2% by weight Gel fine particles 1 0.1% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining Amount [Cyan ink 1] Surface tension: 38 dyn / cm Direct blue 199 2% by weight Gel fine particles 1 0.1% by weight Propylene glycol 15% by weight Diethylene glycol monobutyl ether 5 % Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water Remaining amount The ink of the above formulation is filled in a drop-on-demand type inkjet printer using a piezoelectric element having a resolution of 180 dpi and printing is performed by Gilbert bond paper. As a result, the solid part where the two colors were overlapped was dried within 10 seconds and there was no bleeding. Further, when the recording apparatus was stopped and one month later, printing was performed again, the same image was obtained. Also, when this image was immersed in water for 1 minute and the decrease in image density was examined,
The concentration did not decrease as compared with the case where the gel particles were not included.

Example 2 [Black ink 2] Surface tension: 40 dyn / cm C.I. I. Food black 2 2% by weight Gel fine particles 1 0.4% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining [yellow ink 2] Surface tension: 41 dyn / cm C.I. I. Acid Yellow 23 2% by weight Gel fine particles 1 0.4% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining amount [Magenta ink 2] Surface tension: 40 dyn / cm Acid red 35 2% by weight Gel fine particles 1 0.4% by weight Diethylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Polyethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water remaining amount [Cyan ink 2] Surface tension: 39 dyn / cm Acid blue 254 2% by weight Gel fine particles 1 0.4% by weight Propylene glycol 15% by weight Diethylene glycol monobutyl ether 5% by weight Ethylene glycol alkyl ether 0.3% by weight Lithium hydroxide 0.1% by weight Pure water Remaining amount The above ink was packed in the head of a thermal jet printer Paint Jet manufactured by Hewlett Packard, and printing was performed. A dry and bleed-free image was obtained.

[0016]

[Effect] When the quick-drying ink of the present invention is used, a color image which is quick-drying and has a high image quality can be obtained as compared with the conventional inkjet ink. Further, unlike the conventional emulsion ink, since the particle size of the fine particles is large on the recording paper, even a submicron particle size does not bleed, so that storage stability can be improved. Further, since the dye is retained in the fine gel particles, the water resistance is also improved.

Claims (5)

[Claims] 1. A water-based ink containing a colorant that disperses or dissolves in water, water, and a wetting agent, characterized in that it has polymer gel microspheres in a contracted state that can change in volume due to a change in proton concentration. Quick drying ink. 2. The quick-drying ink according to claim 1, which has a surface tension of 50 dyn / cm or less. 3. The quick-drying ink according to claim 1, which has a pH of 6 or more. 4. The quick-drying ink according to claim 1, 2 or 3 is applied to a target portion of a recording paper, and the polymer gel microspheres in the ink are swollen by donating protons from the recording paper. And the recording method. 5. A method of applying a water-based ink to a recording paper,
The recording method according to claim 4, which is an inkjet method.