JPH11124524A - Inkjet recording ink - Google Patents

Abstract

(57) [Problem] To provide an ink jet recording ink capable of printing with little bleeding even on recycled paper. An ink jet recording ink containing at least a water-soluble coloring material and water contains a highly water-soluble glycol ether and a low water-soluble glycol ether, and the water-soluble glycol ether is added to the water-soluble glycol 1 in an amount of 0. It is characterized in that it is contained at a ratio of 0.5 to 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording ink capable of obtaining high print quality on plain paper, recycled paper or coated paper.

[0002]

2. Description of the Related Art Ink jet recording is a method of discharging characters as droplets from fine nozzles to record characters and figures on the surface of a recording medium. A method of converting an electric signal into a mechanical signal using an electrostrictive element as an ink jet recording method, intermittently discharging ink stored in a nozzle head portion to record characters and symbols on the surface of a recording medium, a nozzle head A method of rapidly heating a part of the ink stored in a part very close to the discharge part to generate bubbles, and intermittently discharging the ink by volume expansion due to the bubbles, thereby recording characters and symbols on the surface of the recording medium. Have been put to practical use.

[0003] The ink used for such ink-jet recording has good drying properties of the print, no bleeding of the print, uniform printing on all surfaces of the recording medium, and mixing of colors in the case of multiple colors. There is a demand for such characteristics as not being present. Here, a particular problem is that when paper is used as a recording medium, bleeding is likely to occur due to fibers having different permeability.

In the conventional ink for ink jet recording, glycol ether is used as a wetting agent as disclosed in Japanese Patent Publication No. 2-907, a water-soluble organic solvent as disclosed in Japanese Patent Publication No. 1-15422, or Japanese Patent Publication No. 2-3837. In many cases, it has been used as a dye dissolution accelerator as disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2002-222,878.

In order to improve the permeability, diethylene glycol monobutyl ether is added as disclosed in US Pat. No. 5,156,675, and US Pat.
No. 3502, Surfynol 465 (manufactured by Air Products), which is an acetylene glycol-based surfactant, is added, or US Pat.
As in the specification of JP-A-6, addition of both diethylene glycol monobutyl ether and Surfynol 465 has been studied. Diethylene glycol mono-n-
Butyl ether is called butyl carbitol and is described, for example, in US Pat. No. 3,291,580.
Alternatively, in US Pat. No. 2,083,372, the use of diethylene glycol ethers in inks has been studied. As an example using a glycol ether having low water solubility, there is an example in which 0.1 to 5% by weight of diethylene glycol monohexyl ether or the like is added as in JP-A-3-14811.

Further, as examples using pigments, in many cases, studies have been made mainly on suppressing the permeability and suppressing the wetting of the ink on the surface of the paper to secure the printing quality, and have been put to practical use. Alternatively, a combination of a glycol ether and a pigment is disclosed in Japanese Patent Application Laid-Open No.
There is an example using ethers of ethylene glycol, diethylene glycol or triethylene glycol as in JP-A-111165.

[0007]

However, in the prior art, there are many cases where the permeability of the ink to the paper is insufficient, and the method of suppressing the wetting on the surface of the paper is not suitable for plain paper, especially recycled paper which is frequently used. There is a problem that when printing is performed continuously, the ink on the printed paper cannot easily be superimposed because the ink on the printed paper is difficult to dry, since the ink spreads and takes a long time to dry the print. Also, recycled paper is a collection of various paper components mixed with different penetration rates,
Bleeding is likely to occur due to the difference in their penetration rates. In order to reduce the bleeding, a method of heating paper is generally studied. However, if paper or other printing materials are heated during printing, it takes time to start up the heating unit in the apparatus to a predetermined temperature, the power consumption of the apparatus body increases, or paper or other printing materials are heated. There is a problem that the printed matter is adversely affected.

[0008] In the case of printing on paper or the like having a normal sizing agent as a recording medium with an ink using a pigment,
If the ink is not imparted with a certain degree of permeability, the pigment remains on the surface of paper or the like, and there is also a problem that the abrasion is deteriorated. However, if the permeability is halfway, the type of paper is limited in order to perform uniform printing, and the printed image is likely to be deteriorated.

Therefore, the present invention solves such a problem, and an object of the present invention is to provide a very fast penetrable paper, especially for recycled paper which is frequently used in recent years, without providing a heating means. It is an object of the present invention to provide an ink jet recording ink capable of performing printing with almost no bleeding, and an ink jet recording apparatus using the ink.

[0010]

The ink jet recording ink of the present invention contains at least a water-soluble coloring material and a water-soluble ink jet recording ink containing a highly water-soluble glycol ether and a low water-soluble glycol ether. The ratio of the high water-soluble glycol ether / the low water-soluble glycol ether is 0.5 to 10.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention requires that the ink used for ink-jet recording has properties such as good print drying properties, no print bleeding, and uniform printing on all surfaces of the recording medium. This is the result of intensive studies in view of the fact that

[0012] The (mono, di) propylene glycol monobutyl ether, (di, tri) ethylene glycol mono (pentyl, hexyl) ether, propylene glycol (mono, di), which are low water-soluble glycol ethers which may be used in the present invention. Use of one or more selected from ethylene glycol mono (butyl, pentyl, hexyl) ether and ethylene glycol (mono, di) propylene glycol mono (butyl, pentyl, hexyl) ether to penetrate paper such as recycled paper Although the bleeding is reduced by improving the water solubility, it cannot be contained in the ink in a large amount due to low water solubility. Therefore, by simultaneously adding a highly water-soluble glycol ether, the amount of the low-water-soluble glycol ether to be added is increased, and at the same time, the (di, tri) ethylene glycol monobutyl ether is considered to be suitable for the present invention. The combination of these improved the print quality.

The addition ratio of the highly water-soluble glycol ether to the low water-soluble glycol ether is 0.5 to 10
It is preferred that Within this range, the desired print quality can be ensured, and the viscosity of the ink within an appropriate range.
In addition, an ink that does not undergo layer separation from other ink components can be obtained. This ratio is more preferably from 1 to 4 and more preferably from 1.5 to 2.5 from the viewpoint of ease of use such as printing stability and viscosity.

As a further preferred embodiment, the above-mentioned ink for ink jet recording may contain an acetylene glycol-based surfactant, and the addition amount thereof is preferably 0.1 to 5% by weight. At less than 0.1% by weight, no improvement in print quality was observed, and at more than 5.0% by weight, no increase in print quality was observed even when more than 5.0% by weight was added.

As an acetylene glycol-based surfactant, there is a surfactant having low water solubility such as, for example, Surfynol 104 (Air Products). Therefore, the solubility can be increased by further adding a solvent or the like. Examples thereof include nonionic or anionic surfactants in addition to solvents such as 1,5-pentanediol, 1,6-hexanediol, and dipropylene glycol. An even more preferred addition amount of the acetylene glycol-based surfactant is 0.3 to 2.0% by weight.

In the ink jet recording ink according to the present invention, the amount of the above-mentioned highly water-soluble glycol to be added is 3 to 30% by weight. In the present invention, the highly water-soluble glycol ether also contributes to the improvement of printing quality by improving the permeability,
The addition amount was preferably 3% by weight or more. 30% by weight
If it exceeds 300, the viscosity of the ink becomes too high and it becomes difficult to use it for ink jet printing. The amount of the low water-soluble glycol is 1 to 30% by weight. When the amount of the low water-soluble glycol ether is less than 1% by weight, the print quality is not improved much. Therefore, the amount is preferably 1% by weight or more. Since there are some substances that undergo phase separation at room temperature, the content is preferably 30% by weight or less.

In addition, even in the case of the above-mentioned high water-soluble glycol ether and low water-soluble glycol ether, when the molecular weight is large, the amount to be added is further limited, so that the amount that can be added is different depending on each substance.

It is preferable to add a water-soluble glycol to suppress drying at the front of the nozzle of the ink.
Examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less,
1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol, pentaerythritol, etc. There is.

In the present invention, many kinds of saccharides can be used in order to prevent the ink from drying and clogging on the front surface of the nozzle. There are monosaccharides and polysaccharides, glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitolose, maltose, cellobiose, sucrose, trehalose, maltotriose and the like, alginic acid and its salts, cyclo Dextrins and celluloses can be used. The addition amount is preferably 0.05% or more and 30% or less. 0.05%
If it is less than 30%, the effect of recovering the clogging phenomenon in which the ink dries at the tip of the head and becomes clogged is small, and if it exceeds 30%, the viscosity of the ink increases and proper printing cannot be performed.

The common saccharides monosaccharides and polysaccharides glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose,
A more preferable addition amount of aldonic acid, glucitolose, maltose, cellobiose, sucrose, trehalose, maltotriose and the like is 3 to 20%. Alginic acid and its salts, cyclodextrins and celluloses need to be added in such an amount that the viscosity of the ink does not become too high.

Further, in order to further control the permeability of the ink according to the present invention or to improve the water solubility of a component which is preferably used in the present invention, a nonionic surfactant or an amphoteric surfactant is used. Can be used to improve the solubility, and other types of glycol ether organic solvents can be added. Further, as its components, additives such as preservatives, antioxidants, conductivity adjusters, pH adjusters, viscosity adjusters, surface tension adjusters, oxygen absorbers, nozzle clogging preventives, etc. may be used as appropriate. it can.

The surfactant to be added is preferably a surfactant having good compatibility with the ink system shown in the present embodiment, and among the surfactants, a surfactant having high permeability and being stable is preferred. Examples thereof include amphoteric surfactants and nonionic surfactants.

Examples of the amphoteric surfactant include betaine lauryldimethylaminoacetate, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, betaine coconut fatty acid amide propyldimethylaminoacetate, polyoctylpolyaminoethylglycine and other imidazolines. Derivatives.

Examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, and polyoxyethylene lauryl ether. , Polyoxyethylene alkyl ethers, ethers such as polyoxyalkylene alkyl ethers, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate Esters such as sorbitan sesquiolate, polyoxyethylene monooleate, polyoxyethylene stearate Other fluoroalkyl ester, and the like fluorine-containing surfactants such as perfluoroalkyl carboxylates.

Also, for example, sodium benzoate, sodium pentachlorophenol,
Sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2
-Dibenzisothiazolin-3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN, manufactured by ICI) and the like may be added.

[0026]

Next, specific embodiments will be described.

The case of using a dye, a case of using a pigment, and the case of using a dye and a pigment are described below.

The water-soluble pigments 1-4 in the following table have a particle size of 10
The surface of carbon black having a dispersity of 10 or less at a wavelength of 300 nm or less is subjected to a dispersion treatment by oxidation to give a structure having a carbonyl group, a carboxyl group, a hydroxyl group, a sulfone group, or the like at its terminal. Each average particle size is shown in () in (). Acrylic acid emulsion was used as the polymer fine particles. The water-soluble dye 1 has a structure represented by the following general formula (I), the water-soluble dye 2 has a structure represented by the following general formula (II), each having the structure specified in the examples, and the water-soluble dye 3 is a direct blue 86 The water-soluble dye 4 is Acid Red 52.

[0029]

Embedded image

[0030]

Embedded image

[0031] In the water-soluble dye 1, A in the general formula (I) is COOK,
X and Y are methyl groups and M is potassium.

(Example 5) Water-soluble pigment 1 (105) 3.0 Water-soluble dye 1 1.0 EDGmPeE 2.0 EGPGmPeE 2.0 EDGPGmBE 2.0 DEGmME 1.0 EGmEE 2.0 DEGmBE 6.0 High Molecular fine particles 1.0 PEG400 4.0 Propylene glycol 6.0 Surfynol 485 0.3 Surfynol 465 0.5 Monopropanolamine 0.9 Monomethylethanolamine 0.1 Ammonia 0.3 Magnesium hydroxide 0.2 Ion exchange Water remaining amount In water-soluble dye 1, A in the above general formula (I) is COON.
a, X and Y are methyl groups and M is sodium.

Example 6 Water-soluble dye 2 5.0 TEGmPeE 2.0 PGEGmPeE 2.5 EGDPGmPE 1.5 DEGmEE 1.0 TEGmBE 6.0 DEGmBE 3.0 Propanediol 5.0 Propylene glycol 3.0 Thio Diglycol 2.0 1,5-pentanediol 1.0 Surfinol 104 0.3 Sasurfinol 465 0.5 Dimethylethanolamine 0.5 Aluminum hydroxide 0.1 Deionized water Remaining amount Water-soluble dye 2 In the general formula (II), m is 1, n is 1, and M is potassium.

(Example 7) Water-soluble dye 3 5.0 PGDE GmBE 3.0 PGDE GmHE 3.0 DEGmPE 3.0 DEGmBE 7.0 1, 4-butanediol 5.0 Tetrapropylene glycol 3.0 Tetraethylene glycol 2 5.5 Trimethylolpropane 5.0 Dimethylethanolamine 1.0 Tetramethylammonium 0.5 Sodium hydroxide 0.1 Surfynol 465 1.0 Triethanolamine 0.5 Deionized water Remaining amount (Example 8) Water solubility Dye 4 5.5 PGDEmmBE 6.0 DEGmBE 8.0 Glycerin 5.0 Diethylene glycol 5.0 Tripropylene glycol 5.0 Surfynol 465 1.0 Triethanolamine 0.9 Potassium hydroxide 0.1 Ion-exchanged water Remaining amount Used for comparative example The composition of the ink thus obtained is as follows. As the pigment shown in the comparative example, carbon black dispersed using a random copolymerization type styrene acrylic acid-based dispersant was used. The average particle size of the pigment is shown in parentheses in units of nm.

(Comparative Example 1) Water-soluble pigment 9 (90) 5.0 Glycerin 10.0 Dispersant 3.0 Nonionic surfactant 1.0 Residual ion-exchanged water (Comparative Example 2) Water-soluble dye ( Food Black 2) 5.5 DEGmME 7.0 Diethylene glycol 10.0 2-Pyrrolidone 5.0 Ion-exchanged water Remaining (Comparative Example 3) Water-soluble pigment 11 (110) 5.5 Water-soluble dye (Food Black 2) 2 5.5 Diethylene glycol 10.0 Nonionic surfactant 1.0 Ion-exchanged water Remaining The above-mentioned symbols indicate the following substances.

PGmBE: propylene glycol monobutyl ether, DPGmBE: dipropylene glycol monobutyl ether, DEGmPE: diethylene glycol monopropyl ether, DEGmHE: diethylene glycol monohexyl ether, TEGmPeE: triethylene glycol monopentyl ether, TEGm
HE: triethylene glycol monohexyl ether,
PGEGmBE: propylene glycol ethylene glycol monobutyl ether, PGEGmBE: propylene glycol diethylene glycol monobutyl ether, PGEGmPeE: propylene glycol ethylene glycol monopentyl ether, PGDEGMpe
E: propylene glycol diethylene glycol monopentyl ether, PGEGmHE: propylene glycol ethylene glycol monohexyl ether, PGDE
GmHE: propylene glycol diethylene glycol monohexyl ether, EGPGmBE: ethylene glycol propylene glycol monobutyl ether, EG
DPGmBE: ethylene glycol dipropylene glycol monobutyl ether, EGPGmPeE: ethylene glycol propylene glycol monopentyl ether, EGDPGmPeE: ethylene glycol dipropylene glycol monopentyl ether, EGPGmH
E: ethylene glycol propylene glycol monohexyl ether, EDGPGm HE: ethylene glycol dipropylene glycol monohexyl ether, EGm
ME: ethylene glycol monomethyl ether, EGm
EE: ethylene glycol monoethyl ether, DEG
mME: diethylene glycol monomethyl ether, D
EGmEE: diethylene glycol monoethyl ether, TEGmME: triethylene glycol monomethyl ether, TEGmEE: triethylene glycol monoethyl ether, EGmPE: ethylene glycol monopropyl ether, EGmBE: ethylene glycol monobutyl ether, DEGmPE: diethylene glycol monopropyl ether, DEGmBE: diethylene glycol mono Butyl ether, TEGmPE: triethylene glycol monopropyl ether, TEGmBE:
Triethylene glycol monobutyl ether.

The polymer fine particles used in the present invention were prepared by the following method.

A reaction vessel was equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer, and 100 parts of ion-exchanged water was added. Add 0.2 parts. Ion exchange water 7
Parts by weight of potassium lauryl sulfate, 5 parts of styrene, 6 parts of tetrahydrofurfuryl acrylate, 5 parts of butyl methacrylate and 0.02 of t-dodecyl mercaptan
Is added dropwise to the monomer solution at 70 ° C. to produce a primary substance. To the primary substance, 2 parts of a 10% solution of ammonium peracid was added, and 30 parts of ion-exchanged water was added.
Parts, potassium lauryl sulfate 0.2 part, styrene 30 parts, butyl methacrylate 15 parts, butyl methacrylate 16
, 2 parts of acrylic acid, 1 part of 1,6-hexanediol dimethacrylate, and 0.5 part of t-dodecylmercaptan were added thereto with stirring at 70 ° C., polymerized, and then neutralized with ammonia. Then, a polymer fine particle aqueous solution having a pH of 8 to 8.5 was prepared.

Table 1 shows the bleeding evaluation results when characters were printed as the printing evaluation results. In Table 1, A is very good, B is good, C is bad, and D is very bad.

[0040]

[Table 1]

As is clear from the results in Table 1, the inks used in the comparative examples have poor print quality, and the inks for ink jet recording used in the present invention have good print quality.

The printing evaluation was performed by using an ink jet printer, MJ-930C (trade name, manufactured by Seiko Epson Corporation). The papers used in these evaluations were plain papers commercially available from Europe, the United States and Japan, and Conqueror.
Paper, Favorite Paper, Modo Copy Paper, Rap
id Copy paper, EPSON EPP paper, Xerox
4024 paper, Xerox 10 paper, Neenha B
ond paper, Riccopy 6200 paper, Yamayuri paper, X
erox R paper.

The amount of Proxel XL-2 was 0.1 to 1% in the remaining amount of water in the embodiment to prevent corrosion of the ink.
Benzotriazole was added in an amount of 0.001 to 0.05% to prevent corrosion of the inkjet head member.

In the present invention, an ink jet recording apparatus having a nozzle with a water-repellent tip is used. This is to make it difficult for the ink to stick to the tip of the nozzle.
In this embodiment, the tip of the nozzle is formed of stainless steel,
A layer formed by forming a water-repellent layer, which was plated thereon by eutectoid plating of polytetrafluoroethylene and nickel and heat-treated, was used. In this case, not only nickel but also eutectoid plating with strong oxidation resistance such as chromium, titanium, gold, platinum, silver, iridium and the like may be used.

Since the ink jet recording ink according to the present invention has high wettability, when the front surface of the nozzle is a normal stainless steel or other metal surface, the wettability causes disturbance when printing is performed with the conventional ink jet recording ink. It was easy. Therefore, when an ink printing test using a normal water-soluble coloring material and a surfactant was performed, the ink was stuck to the nozzle tip and printing disorder occurred from about 100 pages. With the ink for use, there was little sticking and continuous printing of 20,000 pages or more was possible.

It is necessary that the contact angle between the water-repellent structure surface and the ink for ink jet recording is 50 ° or more from 15 ° C. to 45 ° C. If the contact angle is less than 50 ° at an actual use temperature of 5 ° C to 45 ° C, printing disorder is likely to occur and printing cannot be performed immediately. Further, by using the ink for ink jet recording according to the present invention to maintain the contact angle at 50 ° or more for a long period of time, it was possible to improve the printing quality and make continuous printing possible.

The ink-jet recording inks 5 to 5
The surface tension at 45 ° C. is 20 to 35 mN / m. If the surface tension is less than 20 mN / m, even if a water-repellent layer is formed by eutectoid plating of polytetrafluoroethylene and nickel to form a heat-treated water-repellent layer, the ink is likely to be wet and disturbed in printing. On the other hand, if it exceeds 35 mN / m, the permeability to paper deteriorates, and printing disorder is apt to occur. Therefore, the surface tension is 5 to 45 ° C.
Is preferably 20 to 35 mN / m.

The viscosity of the ink for ink jet recording at 5 to 45 ° C. is 2 to 10 ma. s. 2m
Pa. If it is less than s, even if a water-repellent layer is formed by performing heat treatment by plating with eutectoid plating of polytetrafluoroethylene and nickel, ink is likely to be wet and disturbed in printing. 10 mPa. When the distance exceeds s, the protrusion of the ink becomes unstable, and printing disorder is likely to occur. Therefore, the viscosity at the actual use temperature of 5 to 45 ° C is 2 to 10 ma. s is preferred.

Further, the pH at 5 to 45 ° C. of the ink for ink jet recording is 7.5 to 11. In the present invention, the pigment uses a surface oxidation type, and since the dye uses a direct dye or an acid dye, in such a case, there is a high possibility that the coloring material will agglomerate or decompose on the acidic side, and even in a normal standing Considering the gradual oxidation, the pH is 7.
Five or more were required. If the pH exceeds 11, a part of the ink components may be decomposed, so the pH is preferably 11 or less. The use of a stable dye or ink component outside this range is not limited to this range.

In the ink jet recording apparatus according to the present invention, the above-described head unit includes a head for ejecting ink droplets in response to an electrostrictive element. In the method of heating the head, there is a high possibility that the coloring agent and other components contained in the ink are decomposed and the head is easily clogged. Since such a problem does not occur when the electrostrictive element is used, the ink for inkjet recording according to the present invention could be used stably.

In the ink of the present invention using a glycol ether containing a relatively large amount of a solid such as a colorant,
For a nozzle that does not discharge for a long time, the ink dries on the front surface of the nozzle and the viscosity increases, so that a phenomenon that printing is disturbed easily occurs.
However, when the ink was slightly moved so as not to be ejected on the front surface of the nozzle, the ink was agitated and the ink could be ejected stably. In order to do this, it was easy to control with an electrostrictive element. The method of rapidly heating the vicinity of the nozzle is difficult because it generates bubbles. Therefore, by using the ink for inkjet recording according to the present invention using this mechanism, it is possible to increase the concentration of the coloring material in the ink, and when the coloring material is a pigment, a substance that easily foams such as a polymer fine particle solution. It is possible to stably eject ink with a high color density even when using.

In order to perform fine movement in the ink jet recording apparatus, it is necessary that the amount of the coloring material described in this embodiment is 3% or more and 15% or less by weight. When the amount of addition is small, such a mechanism is often unnecessary, and when the amount of addition of the pigment is large, there is no point in that the color density is hard to increase any more, and when the ink contains a large amount of a solvent other than the coloring material, etc. Cannot achieve further improvement in print quality because the viscosity becomes too high or the permeability reaches a plateau. Also, the effect of the fine movement is so small that the ink is easily ejected with a delay. Therefore, the above range is preferable. A more preferable addition amount is 5% to 10% for both substances.

It is necessary that the fine movement is performed in a portion where ink is not ejected when ink is not ejected. However, when a normal surfactant is used, those having permeability are gradually wetted by the fine movement of the nozzle, and it becomes difficult to control the fine movement. Those having no penetrability tend to foam and deteriorate the printing quality. The print quality of the ink for ink jet recording according to the present invention is improved, and the control of the fine movement is facilitated because there is little bubbling and the tip of the nozzle is hard to wet.

In the present invention, when the coloring material is a pigment, water-soluble polymer fine particles are added. 1% by weight
Not less than 10% by weight. If it is less than 1% by weight, the effect of improving the abrasion resistance is small, and if it exceeds 10% by weight, the viscosity of the ink increases and it becomes difficult to use it as an ink for inkjet recording.

In the present invention, when a pigment is used as a coloring material, it is necessary to add water-soluble polymer fine particles.
A surfactant is used as a micelle-forming agent in the polymer fine particle solution, and the polymer fine particle solution tends to foam under the influence of the surfactant. It is difficult to completely eliminate bubbles when urethane foam is used, and this is likely to be a cause of missing dots in printing. When a normal surfactant was used as a penetrating agent, a large amount of bubbles were generated, and dot missing frequently occurred. However, the ink jet recording ink of the present invention had little foaming, and the occurrence of missing dots was very small.

When surfynol 465, TG, 104 (Air Products), which is an acetylene glycol-based surfactant, and their modified products are used, the permeability is increased and the printing quality is further improved. When the ink cartridge containing the ink is a polyurethane foam, some of these acetylene glycol-based surfactants are adsorbed. Therefore, it is necessary for the ink jet recording apparatus using the ink and urethane foam according to the present invention to add a part of the acetylene glycol-based surfactant described above in consideration of the amount adsorbed on the urethane foam.

As described above, according to the present invention, it is possible to provide a high-quality and practical ink-jet recording ink in which bleeding of a printed image on a recording medium such as paper can be reduced. Further, since the tip of the ink jet head has a water-repellent structure and the contact angle can be set to 50 ° or more at 5 ° C. to 45 ° C., printing is hardly disturbed even in continuous printing, and the ink is kept water-soluble. An ink jet recording device that can suppress bubbles even when filled with ink using a foam structure such as polyurethane foam in the ink cartridge because it can suppress foaming while ensuring permeability. Can be provided.

The present invention should not be considered to be limited to these embodiments, and various changes can be made without departing from the gist of the present invention.

[0059]

As described above, the present invention provides an ink jet recording ink capable of performing printing with little bleeding on plain paper, especially recycled paper, which has been insufficient in the past. The present invention has the effect of providing an ink jet recording apparatus which is less susceptible to dot removal even when a foam is used for a cartridge because of its low performance.

Claims (12)

[Claims] 1. A low water-soluble glycol comprising at least a water-soluble colorant, a high water-soluble glycol ether, a low water-soluble glycol ether and water, wherein the ratio of the high water-soluble glycol ether to the low water-soluble glycol 1 is 0.5 to 10. An inkjet recording ink comprising: 2. The ink for ink-jet recording according to claim 1, wherein the highly water-soluble glycol ether is at least diethylene glycol monobutyl ether and / or triethylene glycol monobutyl ether. 3. The low water-soluble glycol ether is (mono, di) propylene glycol monobutyl ether,
(Di, tri) ethylene glycol mono (pentyl, hexyl) ether, propylene glycol (mono, di) ethylene glycol mono (butyl, pentyl, hexyl)
2. The ink jet recording ink according to claim 1, wherein the ink is at least one selected from ether and ethylene glycol (mono, di) propylene glycol mono (butyl, pentyl, hexyl) ether. 4. The ink for ink-jet recording according to claim 1, wherein the addition amount of the highly water-soluble glycol ether is 3 to 30% by weight. 5. The ink for ink-jet recording according to claim 1, wherein the addition amount of the low water-soluble glycol ether is 1 to 30% by weight. 6. The ink jet recording ink according to claim 1, wherein the ink jet recording ink contains 0.1 to 5% by weight of an acetylene glycol-based surfactant. 7. The ink jet recording ink according to claim 1, wherein at least glycerin, (mono, ditri, tetra, poly) ethylene glycol, (mono, di, tri,
Tetra) propylene glycol, (propane, butane,
2. The ink jet recording ink according to claim 1, comprising at least one selected from pentane, hexane) diol and thiodiglycol. 8. The ink for ink-jet recording, wherein at least (mono, di, tri) ethanolamine, (mono, di, tri) propanolamine, (mono, di) methylethanolamine, ammonia, tetramethylammonium, Hydroxide (lithium, sodium,
Potassium, calcium, magnesium, aluminum)
The ink for inkjet recording according to claim 1, comprising at least one member selected from the group consisting of: 9. The ink jet recording ink according to claim 5, wherein
The inkjet recording ink according to claim 1, wherein the surface tension at 45C is 20 to 35 mN / m. 10. The ink-jet recording ink according to claim 5, wherein
Viscosities between 2 and 10 mPa. s.
The ink for inkjet recording according to the above. 11. The ink-jet recording ink according to claim 5, wherein
The ink for inkjet recording according to claim 1, wherein the pH at -45C is 7.5-11. 12. The ink jet recording ink according to claim 1, which is used in an ink jet recording apparatus provided with an ink jet recording head for discharging ink droplets by an electrostrictive element.