JPH0633006A - Ink composition for ink jet recording and ink jet recording method - Google Patents

Abstract

(57) [Abstract] [Purpose] A clear image can be formed even on plain paper, and the print head can be kept stable without clogging even if printing is left idle for a long time. To provide an ink composition for inkjet recording and a recording method. [Constitution] 0.2-10 wt% of water-soluble dye as a colorant
%, Lithium cations, quaternary ammonium cations, quaternary phosphonium cations, anionic surfactant having at least one cation as a counter ion 0.05 to 10 wt%, water 30 to 95 wt
%, An ink composition for inkjet recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an ink jet recording method applied to the fields of recording the output of a computer, recording images transmitted by facsimile, recording video and photographic images, and the like. The present invention relates to an ink composition and a recording method.

[0002]

2. Description of the Related Art An ink jet recording method for recording an image by ejecting liquid ink from a nozzle is capable of printing on plain paper, easy to support colorization, and high in printing speed. Due to such advantages, printers based on various ejection principles have been commercially available in recent years. As a concrete method of the ink jet method which has been conventionally used, a method of applying pressure to ink in a liquid chamber to eject ink from a nozzle by utilizing deformation of a piezoelectric element such as PZT by voltage application, and a method of turning on / off electrodes There are a method of drawing the ink by controlling the electrostatic field, and a method of giving thermal energy to the ink by a heating element or the like and ejecting the ink from the nozzle by utilizing the volume change due to the phase change. Furthermore, pressure is continuously applied to the ink by a pump or the like so that the ink is continuously ejected from the nozzle, and the charge state of the ink droplet is controlled by an electrode provided in the vicinity of the nozzle to control the flight direction of the ink droplet. By doing so, image recording is also practiced. The present invention relates to the inkjet recording method as described above, and to an ink composition and a recording method used therein.

Conventionally, water-based inks mainly containing water have been used for ink jet recording. This is because water is so safe that it is less harmful when people touch the ink directly, swallow it, or inhale the vapor generated from the ink. It has a high surface tension and therefore gives a sharp image with little bleeding when printed on paper. On the other hand, water-based water-based inks have a poor affinity for paper, especially sized paper, and therefore have a slow penetration speed into the ink paper after the ink droplets have been adhered and printed, resulting in an apparent The drying speed becomes slow, and when there is ink on the paper, the printed matter is touched, the printer's paper transport system is touched, and the next printed paper is touched, which disturbs the image. There was a drawback that it was easy to store.

Further, when a color image is recorded by superposing two or more colors, the ink is not particularly printed at the boundary between the secondary colors, even if the printed image is not touched by a finger or the like as described above. Image distortion due to mixing was likely to occur.

As a means for solving these problems, for example, Japanese Unexamined Patent Publication No. 52-74340 discloses that a sizing agent is not added or a paper with a small addition amount is used as a recording medium. . In addition, JP-A-52-1
5312 and JP-A-56-89594 describe a method of using a paper having a white pigment or a coating layer containing a water-soluble polymer as a main component on its surface as a recording medium. By preparing these special recording media in advance, it is possible to solve the above problems. However, in recent years, it has been strongly desired that printing on general paper used in offices and homes is possible.

Further, in Japanese Patent Laid-Open No. 56-57862, a sizing agent for paper is dissolved by dissolving a high-concentration alkaline compound in the ink so that the pH value of the ink is 12 or more, thereby improving the drying property of the ink. How to increase is described.
This method can increase the permeation rate to some extent for so-called acid paper sized with rosin, but it has no effect on neutral paper, which has been widely used in recent years, and even for acid paper When two colors are overlapped by the recording method, it is impossible to prevent the disturbance of the image at the boundary portion of the secondary color. There is also a problem that the ink having a high pH value acts on the head material for ejecting the ink to shorten the life of the head.

Japanese Unexamined Patent Publication (Kokai) No. 55-145774 discloses an ink in which an aliphatic monohydric alcohol is added to the ink composition to improve the drying property. Even with this ink, it is possible to increase the permeation rate into the paper to some extent, but when an aliphatic monohydric alcohol is added at a high concentration, the dye is precipitated and clogging occurs, and the odor becomes a problem. On the other hand, if the added amount is suppressed to a low concentration, the drying property is insufficient, and it is impossible to prevent the image disturbance at the boundary portion of the secondary color.

Japanese Laid-Open Patent Publication No. 55-29546 discloses a method of adding a surfactant to the ink composition to enhance the permeability of the ink. In this method, by selecting an appropriate surfactant, the penetrability can be made higher than that of the above-mentioned ink, so that it is possible to prevent the disturbance of the image at the boundary portion of the secondary color. However, when a commercially available surfactant is used, there is a problem in that the surfactant acts to swell or dissolve an organic member such as a plastic or an adhesive constituting the head, thereby shortening the life of the head. However, there is a problem in that the ink does not always occur and the ink does not have sufficient resistance to clogging.

As a method for improving the anti-clogging property of ink, a lithium salt of a dye is disclosed in JP-A-57-202358, and a quaternary ammonium ion salt of a dye is disclosed in JP-A-62-149770. JP-A-63-48374 discloses an ink composition using a quaternary phosphonium ion salt of a dye. However, most commercially available water-soluble anionic dyes are sodium salts, and in order to exchange the counter ions of the dyes, complicated and costly operations such as acid folding, ion exchange resin treatment, salt folding and the like are required.

Japanese Unexamined Patent Publication (Kokai) No. 57-90070 discloses an aqueous ink composition for ink jet recording containing a perfluorosulfonic acid salt as an anionic surfactant, and it is described that a potassium salt of this surfactant is particularly preferable. ing. However, the effect intended by the present invention cannot be obtained with a surfactant having potassium as the counter ion.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide means for solving the problems of the ink jet recording ink and the recording method which have been conventionally used as described above. More specifically, clear color images can be obtained even on paper commonly used in offices, etc., and even if left unused for a long period of time, clogging does not occur and printing is possible even after long-term use. An object of the present invention is to provide an ink composition for inkjet recording and a recording method capable of maintaining the stability of the head.

[0012]

The constitution of the present invention for solving the above-mentioned problems is an ink composition for ink jet recording and an ink jet recording method as described in the claims.

The essential components of the ink composition according to the present invention are 0.2 to 10 wt% of water-soluble dye, 30 to 95 w.
t% water, 0.05-10 wt% lithium cation,
Quaternary ammonium / cation, quaternary phosphonium /
An anionic surfactant having at least one cation selected from cations as a counter ion.

Conventionally known water-soluble dyes can be used in the present invention. Among the water-soluble dyes, anionic dyes are preferably used in the present invention. Examples of the water-soluble dyes preferably used in the present invention among the dyes described in the color index include the following dyes.

C. I. Acid Yellow 17,2
3, 42, 44, 79, 142 C.I. I. Acid Red 1,13,14,18,2
6,27,35,37,42,52,82,87,8
9,92,97,111,114,115,134,1
86, 249, 254, 289, C.I. I. Acid Blue 9,29,45,89,9
2,249 C.I. I. Acid Black 1,2,7,24,2
6,94 C.I. I. Food Yellow 3,4 C.I. I. Hood Red 7, 9, 14 C.I. I. Food Black 1, 2 C.I. I. Direct Yellow 1,12,26,3
3,44,50,86,120,132,142,14
4 C. I. Direct Red 1,9,13,17,2
0, 28, 31, 39, 80, 81, 83, 89, 22
5,227 C.I. I. Direct Orange 26,29,62,1
02 C. I. Direct Blue 1,2,15,22,2
5,71,76,79,86,87,98,163,1
65, 202 C.I. I. Direct Black 19,22,32,3
8, 51, 56, 74, 75, 77, 154, 168 In the present invention, the water-soluble dye is 0.2 to 10 wt% in the ink composition.
%, But when the proportion of dye is as low as 0.2 wt%, a sufficient image density cannot be obtained and 10 w
If it is more than t%, clogging or a decrease in color image saturation is not preferable.

An essential component for the present invention is an anionic surfactant, and the anionic surfactant has the effect of increasing the ink permeability into printer paper and improving the apparent drying property of the ink. Further, in particular, when two or more colors of ink are attached to the same portion of the recording medium in color printing, there is an effect of preventing the image from being disturbed due to the ink mixture at the boundary between the images of different colors. Further, the addition of the anionic surfactant enhances the wettability to the printer head, and the ink can be sufficiently supplied even when the ink is ejected at a high frequency, so that stable ejection can be obtained.

When a cationic surfactant is added to the ink, it has a problem that it interacts with the above-mentioned anionic dye used because of its excellent safety, solubility and light fastness to cause precipitation. . In addition, the above effects can be obtained by adding a nonionic surfactant to the ink. However, when a nonionic surfactant is added to the ink, if plastic or an adhesive is used in the part of the printer that contacts the ink, the member tends to swell and shorten its life. There are severe restrictions on usage, resulting in high costs, and inability to obtain sufficient functionality. Furthermore, when a nonionic surfactant is added to the ink, the effect of preventing clogging during printing pauses, which is obtained in the present invention, cannot be obtained.

In the present invention, the counter ion of the anionic surfactant is lithium cation, quaternary ammonium.
It must be at least one cation selected from cations and quaternary phosphonium / cations. In addition to these counter ions, conventionally used sodium ions, ammonium ions and free acids may be contained, but they must be within the range that does not impair the effects of the present invention.

Conventionally, there are some examples in which an anionic surfactant is added to the ink for ink jet recording,
Most of the commercially available surfactants are sodium salts, and other free acid types and ammonium salts are commercially available.

In the present invention, the counter ion is a quaternary ammonium-cation or a quaternary phosphonium-cation.
When it is a cation, they have an alkyl group which is unsubstituted or substituted with a hydroxyl group and the number of carbon atoms in one molecule ion is 4
Preferably, the carbon number is more than 12, and when the carbon number is more than 12, the solubility in water decreases, clogging occurs during printing pause or continuous printing, and ink components tend to separate during storage of ink. Become stronger.

The following can be mentioned as examples of these counter ions.

[0022]

[Chemical 1]

[0023]

[Chemical 2]

[0024]

[Chemical 3]

To obtain these salts of anionic surfactants, if the anionic surfactant is obtained in the form of the free acid, the above-mentioned ionic hydroxide is added to the active agent of the free acid or a solution thereof. It is obtained by doing. As a method for converting a commercially available sodium salt type anionic surfactant into a surfactant which forms a salt with a specific counter ion of the present invention, an ion exchange resin containing a desired counter ion and a sodium salt type Examples of the method for changing the direct conversion ion include a method of contacting with an aqueous solution of an active agent, a salting out method of adding a salt containing a desired counter ion to a solution of a sodium salt to precipitate a surfactant, and the like.
Examples of the method of once converting a sodium salt type surfactant into a free acid include a method of treating a sodium salt type surfactant solution using an H type ion exchange resin, a method of treating a surfactant or a strong acid thereof with a strong acid. In addition, a method of obtaining a free acid type surfactant by separating the free acid and then separating it by solvent extraction, distillation, filtration and the like can be mentioned.

In the present invention, in order to further reduce clogging, the counter ion of the anionic compound used in the ink composition other than the surfactant is also a lithium cation, a quaternary ammonium / cation, a A quaternary phosphonium or cation is preferable, but not essential. As for dyes, most of the acid dyes available on the market and direct dyes are sodium salts. The same method as the above-mentioned method for exchanging the ions of the surfactant can be applied to the exchange of the counter ion of the dye in principle, but in reality, the dye cannot be distilled even in the acid form. Even with the method described above, since the resin is clogged, there is a problem that the life thereof is short and the cost is high. Compared to dyes, surfactants can exchange ions relatively easily, and the ink of the present invention has an effect of preventing clogging even when a commercially available sodium dye is used.

When a free acid type anionic surfactant is available, the free acid type surfactant is added at the time of ink preparation, and moreover, a hydroxide of counter ion is added in an approximately equivalent amount or more to obtain an ink pH value. By adjusting the value to be 6.0 or more, an ink composition in which clogging hardly occurs can be obtained very easily.

The following compounds may be mentioned as examples of anionic surfactants that can be used in the present invention. That is, as a sulfonic acid type surfactant, an alkyl sulfonate, an alkylbenzene sulfonate, an alkylnaphthalene sulfonate, a mono- or dialkyl sulfosuccinate, an α-olefin sulfonate, N-
Examples of the acyl sulfonates and sulfates include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl aryl ether sulfates, and alkyl omido sulfates.

Examples of the carboxylic acid type surfactants include higher fatty acid salts, N-acyl amino acid salts, polyoxyethylene alkyl ether carboxylic acid salts, and acylated peptides.

As the phosphoric acid type surfactant, monoalkyl phosphate, dialkyl phosphate, trialkyl phosphate, polyoxyethylene alkyl ether phosphate, bispolyoxyethylene alkyl ether phosphate, tris poly Examples thereof include oxyethylene alkyl ether phosphate, polyoxyethylene alkylaryl ether phosphate, bispolyoxyethylene alkylaryl ether phosphate and tris polyoxyethylene alkylaryl ether phosphate.

Examples of the silicon-based anionic surfactant include carboxylic acid-modified polydimethylsiloxane and sulfonic acid-modified polydimethylsiloxane.

Fluorine-based anionic surfactants such as fluoroalkyl carboxylates, perfluoroalkyl sulfonates, perfluoroalkenyl aryl sulfonates, N-perfluorooctane sulfonyl glumates, perfluoroalkyl-N-ethyl sulfonyl glycines. Salt, perfluoroalkylsulfonamidopropyltrimethyl salt, 3- (ω-fluoroalkanoyl-N-
Examples thereof include ethylamino) -1-propanesulfonate and perfluoroalkylethyl phosphate ester salts.

The anionic surfactants that can be used in the present invention have been mentioned above. What compounds are used as the anionic surfactants, what is the chain length of the alkyl group, and what has a branch? Or more specific compound such as the length of polyoxyethylene group is used, the volume per drop of the target printer, the recording medium when two or more colors are overlapped in color printing. An appropriate compound must be selected according to the conditions under which the ink is used, such as the number of dots printed per unit area, the printing speed, and the guaranteed environmental condition range. Whichever surfactant is used, the alkyl group preferably has 4 to 23 carbon atoms and is branched, and the polyoxyethylene group preferably has 3 to 20 ethylene oxide groups per molecule.

Further, the addition amount should be selected at an appropriate level depending on the kind of the surfactant to be used, other components in the ink such as dye and wetting agent, and the conditions under which the ink is used. Especially for a surfactant having a low solubility, the addition amount must be suppressed to a low value so that separation does not occur during use or during storage. Regardless of which surfactant is used, the preferred amount of the surfactant added is in the range of 0.05 to 10 wt%. When the addition amount is 0.05 wt%, the effect of the addition is insufficient, and it is impossible to prevent the image from being disturbed particularly when two or more colors are overlapped in color printing. If it is added in an amount of more than 10 wt%, the surfactant itself or the dye tends to be separated during use or storage, and the viscosity becomes high, making ejection from the head difficult.

In the present invention, in addition to the above compounds, it is preferable to contain 3-70 wt% of a polyhydric alcohol as a wetting agent. By using polyhydric alcohols, it is possible to add suitable physical properties to the ink for jetting and to provide an effect of preventing clogging during printing suspension. When the content of the polyhydric alcohol is less than 3 wt%, addition of the anionic surfactant has an adverse effect on clogging as compared with the case where no addition is made. When the content is more than 70 wt%, the viscosity is high and it is not suitable for ejecting ink.

Specific examples of the polyhydric alcohols used in the present invention include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, glycerin, thiodiglycol, polyglycene and hexa. Methylene diol, 1,
5-pentanediol, 1,6-hexanediol,
Specific examples include 2,5-hexanediol and 2,4-hexanediol.

In the present invention, it is preferable to use the above-mentioned polyhydric alcohols, but a conventionally known wetting agent selected from the following compounds may be mixed with the above-mentioned polyhydric alcohol or without being mixed with the polyhydric alcohol. Can be used.

That is, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol, diethylene glycol monoethyl ether, Triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether,
Propylene glycol monoethyl ether, ethers of polyhydric alcohols such as N-methyl-2-pyrrolidone,
Heterocyclic compounds such as 1,3, -dimethylimidazolidinone and ε-caprolactam, and alcohol amines such as monoethanolamine, diethanolamine and triethanolamine.

In addition to the above components, it is preferable to add a water-soluble polymer compound having a molecular weight of 1000 or more to the ink of the present invention. In particular, it is preferable to contain a nonionic or anionic polymer compound. When a cationic water-soluble polymer compound is used, it tends to interact with the dye to cause precipitation, as in the case of using a cationic surfactant. In the present invention, when the water-soluble polymer compound is not added, the effects of improving the drying property, preventing the color image from being disturbed, enabling ejection at high frequency, and preventing clogging can be obtained. Image bleeding, dots spread too much depending on the paper type, and streaks appear in the main scanning joint,
It is observed that the image density is lowered.
The above problem can be solved by adding a water-soluble polymer compound to the ink in an amount of 0.05 to 7 wt%. If the molecular weight is 1000 or less, the above effect cannot be obtained.

Examples of the water-soluble polymer compound that can be used in the present invention include the following compounds.

That is, polyacrylic acid salts, polymethacrylic acid salts, alginates, carboxymethyl cellulose, gum arabic, salts of hydrolyzed compounds of styrene-maleic anhydride copolymers, hydrolyzed compounds of styrene-isobutylene-phthalimide copolymers. Salt of hyaluronic acid,
Examples thereof include gellan gum, a condensate of naphthalene sulfonic acid and formalin, polyvinyl aryl sulfonate, water-soluble polyamide, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylamide, and the like. Among these polymer compounds, especially polyacrylate, polymethacrylate, alginate, carboxymethylcellulose, gum arabic,
The use of a high molecular polymer containing a carboxyl group such as a salt of a hydrolyzed compound of a styrene-maleic anhydride copolymer, a salt of a hydrolyzed compound of a styrene-isobutylene-phthalimide copolymer, or the like spreads dots too much. It is preferable for preventing the above-mentioned phenomenon and obtaining a high image density. When using an anionic polymer compound, like the surfactant,
The counter ion is particularly preferably a salt with an ion selected from lithium cation, quaternary ammonium cation, and quaternary phosphonium cation.

The amount of these water-soluble polymer compounds added to the ink must be selected according to the compound to be used and the desired characteristics. However, whichever compound is used, the addition amount is 0. If it is less than 05 wt%, the above-mentioned effect cannot be obtained, and if it is more than 7 wt%, the viscosity becomes too high, or the structure becomes viscous and stable ink ejection becomes impossible, and clogging occurs. The problem arises that it becomes easier.

In the present invention, in addition to these materials, known compounds such as antiseptics, oxygen absorbers, rust preventives, ultraviolet absorbers and radical inhibitors can be added according to the purpose.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, the amount (%) of each component described in the examples is based on weight.

Example 1 <Black ink formulation> C.I. I. Direct Black 154 2.0% Diethylene glycol 5.0% Glycerin 3.0% N-Methyl-2-pyrrolidone 3.0% Dodecylbenzenesulfonic acid 1.0% Alginic acid 0.1% Ion-exchanged water 83.9% Above While stirring the mixture of the formulations at 50 ° C., a 30 wt% aqueous solution of tetramethylammonium (A-1) hydroxide was added to adjust the pH value to 8.0. Stirring was continued for 4 hours as it was, and after cooling, filtration was performed with a filter having a pore size of 1 μm.

With the above formulation, C.I. I. In place of Direct Black 154, the following dyes were added, and the addition amount of dodecylbenzene sulfonic acid was adjusted to an appropriate amount according to each dye, and the amount of dye or surfactant less than the above formula was ion-exchanged. Water was added and each color ink was prepared as above.

<Yellow Ink Formulation> C. I. Acid Yellow 23 1.0% Dodecylbenzenesulfonic acid 1.0% <Magenta ink formulation> C.I. I. Acid Red 35 1.5% Dodecylbenzenesulfonic acid 1.0% <Cyan ink formulation> C.I. I. Acid Blue 249 2.0% Dodecylbenzenesulfonic acid 0.6% After removing air dissolved in this ink by leaving it under reduced pressure, a known on-demand type color inkjet using PZT as an electrostrictive element. The printer was filled in, and a printing test described below was performed under the following conditions to perform a reliability test. Drive frequency: 8 KHz Drive voltage: 25v Nozzle diameter: 43 μm Droplet volume: 93 pl / dot Nozzle number: 64 nozzles for each color Dot density: 300 dpi Test 1 (T1) Initial printing test Up to 2 colors are completely overlaid and commercially available Color printing was performed on 3 types of copy papers and bond papers, and the presence or absence of image distortion at the image boundary portion where the two colors were overlapped, the dot diameter, and the image density were examined. The sizing degree was 3.3 to 37 seconds.

Test 2 (T2) Continuous Jet Responsiveness Test One head was used to continue jetting while printing an image at regular intervals until the number of jet dots per nozzle reached 10 ⁸ .

Test 3 (T3) Jet Responsiveness Test after Pause of Printing After the printer was left in the environment of 40 ° C. and 20% RH for 1 month, printing was performed to test whether or not normal printing was possible.

Test 4 (T4) Ink storage test Each ink was stored for 1 month under each condition of −20 ° C., room temperature, and 50 ° C., and the ink after storage was visually observed to check for the presence of separated substances. Moreover, the presence or absence of a precipitate was examined from the filterability.

As shown in Table 1, in the initial image, the color image obtained was clear without any disturbance, and the dot diameter was within a relatively narrow range of 110 to 135 μm on each paper. The concentration was also sufficient. Also,
No problems occurred even when printing was performed after continuous jetting and printing pause. In addition, there was no problem with the storage stability of the ink.

Comparative Example 1 In the ink formulation of each color of Example 1, an ink was prepared in which sodium salt was used instead of the free acid of dodecylbenzenesulfonic acid, and the pH value after mixing was adjusted to 8.0 with sodium hydroxide. did.

After performing the same treatments as in Example 1 with these inks, the inks were filled in a printer and printing and storage tests were conducted.

As shown in Table 1, with these inks, there were no problems in the initial image, continuous jet test, and ink storability, but in the print pause test, clogging occurred and printing was impossible.

Comparative Example 2 An ink having the same formulation as that of Example 1 except that dodecylbenzenesulfonic acid was not added and the amount of ion-exchanged water was increased by the same amount was prepared, filtered, and deaerated as in Example 1. , Each test was conducted.

Using these inks, as shown in Table 1, the ejection stability was unstable when the driving frequency was 8 KHz, and the initial printing was performed at 2 KHz. The obtained image had a remarkable disorder at the solid boundary.
When continuous injection was performed at 2 KHz, discharge from all nozzles became impossible midway. Since the ink was recovered by the suction operation and was able to be ejected, it was presumed that the air entered the liquid chamber was the cause of the ejection failure. Further, even when printing was stopped, clogging occurred and printing became impossible.

Comparative Example 3 In the ink formulation of each color of Example 1, n- was used as the nonionic surfactant instead of dodecylbenzenesulfonic acid.
An ink to which a triethylene oxide adduct of decyl alcohol was added was prepared, filtered and deaerated in the same manner as in Example 1, and each test was conducted.

As shown in Table 1, when these inks were used, the initial print image was almost the same as that of Example 1, but in continuous jetting, ejection of all nozzles became impossible. Since it is impossible to re-eject even if recovery is performed by a suction operation, it is presumed that the adhesive that joins the liquid chambers is eroded to cause ejection failure. Further, even when printing was stopped, clogging occurred and printing became impossible.

Reference Example 1 In the ink formulation for each color of Example 1, an ink in which alginic acid was not added and the amount of ion-exchanged water was increased by that amount was prepared, filtered, and deaerated in the same manner as in Example 1, and each test was conducted. It was

As shown in Table 1, when these inks are used, the disturbance of the image boundary does not occur in the initial print image, but the dot diameter greatly varies depending on the paper type, and the image density becomes slightly low as a whole. .

Example 2 <Black ink formulation> C.I. I. Direct Black 168 4.0% Polyethylene glycol 3.5% Ethylene glycol 6.5% Diethylene glycol 10.0% Di- (2-ethylhexyl) succinic acid lithium salt 1.8% Styrene-maleic anhydride copolymer hydrolysis Substance salt 0.3% sodium dehydroacetate (preservative) 0.3% ion-exchanged water 73.9% <yellow ink formulation> C.I. I. Direct Yellow 132 1.5% Tetraethylene glycol 3.5% Ethylene glycol 6.5% Diethylene glycol 10.0% Didi- (2-ethylhexyl) sulfosuccinic acid tetrapropylammonium salt 1.2% Styrene-maleic anhydride copolymer Combined hydrolyzate salt 0.3% Sodium dehydroacetate (preservative) 0.3% Ion-exchanged water 77.0% <Magenta ink formulation> C.I. I. Direct Red 227 2.0% Glycerin 3.5% Diethylene glycol 10.0% Thiodiglycol 6.5% Lauroyl sarcosine tetraethylphosphonium salt 1.3% (Counter ion of P-2) Alginic acid tetramethylammonium salt 0 1% Sodium dehydroacetate (preservative) 0.3% Ion-exchanged water 76.9% <Cyan ink formulation> C.I. I. Direct Blue 199 2.5% Diethylene glycol 10.0% Ethylene glycol 5.5% 1,3-Dimethylimidazolidinone 3.5% N-lauroylmethyl taurine salt 1.0% (Ex. A-12 counter ion) ) Styrene-maleic anhydride copolymer hydrolyzate salt 0.2% sodium dehydroacetate (preservative) 0.3% ion-exchanged water 77.2% A test was conducted in the same manner as in Example 1 using the above ink. . However, the head and its driving conditions were changed to have the following values.

Driving frequency: 6 KHz Driving voltage: 30 v Nozzle diameter: 35 μm Droplet volume: 71 pl / dot Number of nozzles: 64 nozzles of each color Dot density: 300 dpi The results are shown in Table 1, and the obtained color was obtained in the initial image. The image was not disturbed and was clear, the dot diameter was in a relatively narrow range of 114 to 132 μm on each paper, and the image density was sufficient. Further, no particular problems occurred in the continuous jetting and the printing after the printing was stopped. In addition, there was no problem with the storage stability of the ink.

Example 3 <Black ink formulation> C.I. I. Direct Black 19 3.5% Glycerin 15.0% Diethylene glycol 20.0% Hexylene glycol 5.0% Lauryl sulfate (Ex. A-11 counter ion) 1.1% Polyacrylate 0.05% Ion-exchanged water 55.35% <Yellow ink formulation> C.I. I. Direct Yellow 86 2.0% Polyethylene glycol 200 10.0% Ethylene glycol 20.0% N-Methyl-2-pyrrolidone 8.0% Bis- (octaethylene oxide alkyl ether) lithium phosphate 1.2% Alginic acid Lithium salt 0.2% Ion-exchanged water 58.6% <Magenta ink formulation> C.I. I. Direct Red 254 2.5% Triethylene glycol 12.0% Diethylene glycol 10.0% Thiodiglycol 15.0% Tris- (octaethylene oxide alkyl ether) phosphate (Ex. A-6 counter ion) 2.0% Tetramethylammonium alginate 0.1% Sodium dehydroacetate (preservative) 0.3% Ion-exchanged water 58.19% <Cyan ink formulation> C.I. I. Acid Blue 9 3.0% Ethylene glycol 42.0% Dodecylbenzene sulfonate 0.4% (Exemplary A-8 counter ion) Styrene-maleic anhydride copolymer hydrolyzate salt 0.2% Ion Exchanged water 54.4% A test was conducted in the same manner as in Example 2 using the above ink.

As shown in Table 1, in the initial image, the color image obtained was clear without any disturbance, and the dot diameter was within a relatively narrow range of 118 to 135 μm on each paper. The concentration was also sufficient. Also,
No problems occurred even when printing was performed after continuous jetting and printing pause. In addition, there was no problem with the storage stability of the ink.

Example 4 Inks of the respective colors having the following formulations were prepared, filtered and deaerated in the same manner as in Example 1 and tested in the same manner as in Example 1.

<Black Ink Formulation> C. I. Food Black 2 3.5% Diethylene glycol 5.0% Tetraoxyethylene nonylphenyl ether tetramethylphosphonium sulfate (exemplary P-1 ion) salt 0.6% Carboxymethyl cellulose 0.07% Ion-exchanged water 90.83% <Yellow Ink Formulation> C.I. I. Acid Yellow 17 1.8% Triethylene glycol 4.0% Tetraoxyethylene lauryl ether tetrapropylammonium sulfate (Ex. A-5 ion) salt 2.0% Polyvinyl alcohol 3.5% Ion-exchanged water 88.5% < Magenta ink prescription> C.I. I. Acid Red 289 2.0% Glycerin 4.0% Di (2-ethylhexyl) sulfosuccinate tetrapropylammonium (Ex. A-5 ion) salt 1.5% Polyethylene glycol (molecular weight 2000) 2.5% Ion exchange Water 90.0% <Cyan ink formulation> C.I. I. Acid Blue 199 2.5% Diethylene glycol lauryl sulfate 5.0% Tetrapropylammonium (Ex. A-5 ion) salt 0.6% Lithium alginate 0.2% Ion-exchanged water 91.7% The results of the test are shown in Table 2. As shown, the color image obtained was clear and free from any disturbance, and there were no problems in continuous jetting, printing after the pause of printing, and ink storage.

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

As is apparent from the above invention, the present invention has the following effects.

(1) In the ink composition for ink jet recording according to claim 1, since an anionic surfactant is added, a clear image without disturbance of image boundaries can be obtained when color printing is performed. It becomes possible to drive at high frequency. There is no problem that the organic member constituting the head is eroded as in the case of adding the nonionic activator, or that precipitation occurs when the cationic activator is added. In addition to such an action, in the present invention, the counter ion of the anionic surfactant is an ion selected from a lithium cation, a quaternary ammonium cation, and a quaternary phosphonium cation. Greatly prevents clogging due to suspension of operation.

(2) In the ink composition for ink-jet recording according to claim 2, the counter ion of the anionic surfactant has a quaternary ammonium having an alkyl group having 4 to 12 carbon atoms which is unsubstituted or substituted with a hydroxyl group. Since it is a cation or a quaternary phosphonium cation, it has a large effect of preventing clogging due to the pause of printing in the printer and preventing the occurrence of precipitation during storage.

(3) In the ink composition for ink jet recording according to claim 3, the above-mentioned surfactant or a dye having a lithium cation, a quaternary ammonium cation or a quaternary phosphonium cation as a counter ion is used. Since it contains a polyhydric alcohol that dissolves well, it is particularly effective in preventing clogging due to the pause of printing in the printer.

(4) In the ink composition for ink jet recording according to claim 4, without preparing a surfactant having a lithium cation, a quaternary ammonium cation, or a quaternary phosphonium cation as a counter ion. Since the anionic surfactant dye obtained as the free acid can be directly used in the ink formulation, the ink composition can be produced at low cost.

(5) Since the ink composition for ink jet recording according to claim 5 contains a water-soluble polymer compound having a molecular weight of 1000 or more, image bleeding that easily occurs when a surfactant is added to the ink. It is possible to solve the problems of the occurrence of the image, the decrease in the image density, and the variation in the dot diameter depending on the paper type.

(6) In the color ink jet recording method according to the sixth aspect, since the ink composition containing the surfactant which improves the permeability and does not cause the clogging is used, When recording is performed on general paper having a size degree of more than 3 seconds, it is possible to prevent the disturbance of a superimposed image of two or more colors and obtain a stable image.

Claims (6)

[Claims] 1. A water-soluble dye is used as a coloring agent in an amount of 0.2 to 10
wt%, lithium cations, quaternary ammonium cations, quaternary phosphonium cations anionic surfactant having at least one cation as a counter ion 0.05 to 10 wt%, water 30 to 95 wt
%, An ink composition for inkjet recording. 2. A quaternary ammonium cation or a quaternary phosphonium cation whose counter ion has an alkyl group which is unsubstituted or substituted by a hydroxyl group and which has 4 to 12 carbon atoms in one molecular ion. The ink composition for inkjet recording according to claim 1, wherein 3. The ink composition for ink jet recording according to claim 1, which contains 3 to 70 wt% of a polyhydric alcohol as a water-soluble organic compound. 4. By adding a free acid type anionic surfactant to the ink composition and further adding a composition containing lithium hydroxide, a quaternary ammonium hydroxide and a quaternary phosphonium hydroxide. The ink composition for inkjet recording according to any one of claims 1 to 3, wherein the pH value is adjusted to 6.0 or more. 5. The ink composition for ink jet recording according to any one of claims 1 to 4, which contains 0.05 to 7 wt% of a water-soluble polymer compound having a molecular weight of 1000 or more. 6. A water-soluble dye as a colorant is 0.2 to 10
wt%, lithium cations, quaternary ammonium cations, quaternary phosphonium cations anionic surfactant having at least one cation as a counter ion 0.05 to 10 wt%, water 30 to 95 wt
% For an ink jet recording ink composition having a Steckigt sizing degree of 3 seconds or more and having no pigment-based coating layer on the surface.
An ink jet recording method, characterized in that a color image is recorded by superposing more than one color.