JP2000273376A - Recording liquid for ink jet, and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an on-demand type ink jet ink which is excellent in delivery stability even in a low-humidity environment and can dispense with a long-time preparatory delivery by compounding water with a colorant, a high-boiling-point organic solvent, and a moisture-absorbent solid organic compound. SOLUTION: A compound of formula I is preferable as the moisture-absorbent solid organic compound. In formula I, R is H or a substituent; and m is an integer of 1-4. A compound of formula II is also preferable as the moisture- absorbent solid organic compound. In formula II, R1 to R4 are each independently H or a (substituted)alkyl, aromatic or heterocyclic group provided R1 may combine with R2, R2 may with R3, R3 may with R4 or R4 may with R1 to form an aromatic or heterocyclic ring; X is a halogen or an organic acid residue; and n is an integer of 1-4. Preferably, at least 50 wt.% of the high-boiling-point organic solvent is a compound of the formula: H-(OCH2CH2)1-OH (wherein l is an integer of 1-50).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for an on-demand type ink jet printer, and more particularly to an ink jet ink having improved ejection stability under low humidity conditions.

[0002]

2. Description of the Related Art In an ink jet recording method for recording information by ejecting a controlled ink to a recording material, a recording head is not brought into contact with the recording material, so that there is no noise and high-speed recording is possible. It has advantages such as recording on plain paper.

[0003] Inks used in such an ink-jet recording method often include various dyes or pigments and water or a water-soluble organic solvent which dissolves or disperses them as basic components. Additives are known and used.

[0004] Such inks must have appropriate physical properties to satisfy (1) no clogging in the nozzles of the recording head and (2) ejection characteristics (flying stability, frequency response, etc.). (3) it does not corrode the material in contact with the ink, (4) it is stable for long-term storage, and (5) it is discharged stably under various environments. Is required.

[0005] Further, when the ink is printed on a recording material, the characteristics include (6) quick drying, (7) good printing quality, and (8) storage stability as a recorded image (lightfastness). Properties, water resistance, etc.) are required.

In particular, on-demand type ink jet printers are used very frequently because they discharge ink droplets only when necessary, so that energy is wasted little and the structure is simple. However, in the on-demand type ink jet printer, especially in a low humidity environment, at the discharge port which is capped for a certain period of time or not discharged, the ink viscosity near the discharge port due to evaporation and drying of water increases, and normal discharge is performed. Is not performed.

More specifically, the velocity of the droplet at the time of ejection is reduced,
An increase in the amount of droplets due to merging with the subsequent droplets or deterioration in landing accuracy may cause an image to be disturbed. In severe cases, ejection may not be performed.

In order to prevent this phenomenon, it is usually effective to carry out preliminary ejection unrelated to printing in a cap or a special ejection place. However, if the recording is frequently interrupted to perform the preliminary ejection, the recording time becomes longer, which is not preferable.

On the other hand, if an organic solvent is contained in a large amount for adjusting the viscosity, the time required for drying becomes longer, and the image changes due to bleeding when the image is exposed to high humidity conditions during storage. Therefore, there has been a demand for a method of adjusting the viscosity without increasing the content of the organic solvent, and eliminating ejection failure during drying.

In addition, ink jet printers having a small amount of ink droplets have been required especially as the ink jet recording has become finer. In these printers, a phenomenon that normal ejection cannot be performed due to drying is remarkably observed.

Because, the ease of drying is proportional to the area of the liquid in contact with air. That is, it is proportional to the square of the nozzle opening diameter. However, the droplet volume is approximately proportional to the cube of the opening diameter. Therefore, even if the droplet amount is reduced, the ease of drying does not decrease so much.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method that does not require a long-time preliminary discharge because of excellent discharge stability even in a low humidity environment. Another object of the present invention is to provide an ink-jet ink that may be used.

[0013]

The above object is achieved by the following means.

1. An on-demand type ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent, and a hygroscopic solid organic compound.

2. An on-demand type ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent, and a solid organic compound which is deliquescent at 25 ° C., 50% humidity and 1 atm.

3. An on-demand ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent and a compound represented by the general formula [1].

[0017]

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In the formula, R represents a hydrogen atom or a substituent;
m represents an integer of 1 to 4.

4. An on-demand ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent and a compound represented by the general formula [2].

[0020]

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Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently
Represents a hydrogen atom, a substituted or unsubstituted alkyl group, aromatic group, or heterocyclic group. R ₁ and R _2, R ₂ and R ₃ , R ₃ and R ₄ or R ₄ and R ₁ may form an aromatic ring or a heterocyclic ring. X represents a halogen or an organic acid residue. n is an integer of 1 to 4.

5. An on-demand type ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent and a compound having an azole structure.

6. At least water, a colorant, a high boiling organic solvent and isethionic acid, 3-aminopyridine, dihydroxyacetone dimer or 1- (3-sulfopropyl)
An on-demand type ink jet recording liquid comprising pyridinium hydroxybetaine.

[7] At least water, a colorant, a high-boiling organic solvent and pyridine-N-oxide, tris (hydroxymethyl) aminoethane, ethylamine, thiamine, choline, benzyltrimetrimethylamine, tetraethylamine, pyrazole or 4-hydroxymethyl-5-methylimidazole. An on-demand recording liquid for inkjet characterized by containing.

8. The on-demand type ink jet recording liquid according to any one of the above items 1 to 7, wherein 50% by weight or more of the high boiling point organic solvent is a compound represented by the general formula [3].

General formula [3] H- (OCH ₂ CH ₂ ) ₁ —OH wherein 1 represents an integer of 1 to 50.

9. 8. The on-demand type ink jet recording liquid according to any one of 1 to 7, wherein 50% by weight or more of the high boiling point organic solvent is ethylene glycol.

10. 10. An on-demand type ink jet recording method, wherein the on-demand type ink jet recording liquid according to 1 selected from 1 to 9 above is used for an ink jet discharging apparatus having a minimum droplet volume of 10 pl or less.

(11) 10. An on-demand ink jet recording method, wherein the on-demand ink jet recording liquid according to 1 selected from 1 to 9 above is used for an ink jet ejection apparatus having a minimum droplet volume of 7 pl or less.

12. 10. An on-demand ink jet recording method, wherein the on-demand ink jet recording liquid according to 1 selected from 1 to 9 is used for an ink jet ejection apparatus having a minimum droplet volume of 5 pl or less.

The ink jet recording liquid (ink) contains at least water, a colorant, and a high-boiling organic solvent as basic components. Among them, the high-boiling organic solvent controls the drying property of the ink, prevents the ink from drying at the nozzles of the ink head, and prints on the recording medium so that the ink can be smoothly re-discharged even after a pause. When it is used, it is added so as to dry quickly and reduce the bleeding of the ink, and a high-polarity, high-boiling organic solvent such as ethylene glycol or diethylene glycol is used for this purpose. However, in recent years, higher definition of an image has been desired, and for that purpose, it is necessary to reduce the diameter of ink droplets. However, when the ink droplet size is reduced, drying of the ink in the head is more likely to occur, and nozzle clogging is more likely to occur. Therefore, in order to suppress this, the content of a wetting agent such as ethylene glycol must be increased. However, when this is performed, the ink becomes difficult to dry, and bleeding on the recording medium becomes extremely large. Therefore, there is a demand for a technique for reducing the size of ink droplets in order to obtain a high-definition image and preventing the ink from bleeding when printed on a recording medium without delaying drying.

The present inventors have found that the above object can be attained by incorporating an organic compound which is solid and has a property of absorbing water in a gas phase into the ink composition. Was.

In the present invention, the solid organic compound having the property of absorbing moisture in the gas phase is a solid, hygroscopic compound or deliquescent compound. A solid organic compound is an organic compound that is in a solid state at 25 ° C., 50% humidity, and 1 atm and exhibits hygroscopicity or deliquescent as defined below. The hygroscopicity of these organic compounds is distinguished from the adsorption phenomenon in which the absorbed moisture is stored near the solid surface when left standing.

The solid hygroscopic organic compound used in the present invention is a solid under so-called standard conditions at 25 ° C. and 1 atm.
After standing at 25 ° C., 20% humidity and 1 atm for 24 hours, and then left at 25 ° C., 80% humidity and 1 atm for 1 day, moisture in the gas phase is absorbed and the weight becomes 0. .5%
It is a compound having the property of increasing.

The deliquescent compound is a compound that dissolves in the absorbed water, and is a compound in which the saturated aqueous solution of the compound solid has a water vapor pressure lower than the partial pressure of water vapor at 25 ° C., 50% humidity, and 1 atmosphere. is there. There is no general rule as to which compounds have deliquescent properties, but these hygroscopic compounds, including some well-known, also include these.

The use of these compounds enhances the water retention of the ink, prevents drying by the ink head, eliminates clogging of the nozzles, and at the same time, prints on a recording medium, and reduces ink bleeding and is easy to dry. Can be obtained. Since a conventional compound used to provide water retention uses a liquid, it is impossible to achieve both the drying property of the ink and the clogging of the nozzle.

The reason why the above-mentioned effects can be obtained by using the solid hygroscopic and deliquescent organic compound of the present invention is not exactly known. However, when dissolved as an ink, its hygroscopicity and deliquescent properties can be improved. However, it is considered that drying is quick and little bleeding occurs because the property as a solid appears in the process of printing on the recording medium and evaporating the volatile component.

The hygroscopic compound or deliquescent compound may be any compound as long as it satisfies the above conditions. For example, sodium DL-malate, sodium isethionate, 2-chloroethylamine hydrochloride, Methylolethane, N-methylglycine, N-methylmorpholine-N-oxide, N-methylimidazole,
Trimethylolpropane, tris (hydroxymethyl)
Aminoethane hydrochloride, phenyltrimethylammonium chloride, ethylamine hydrochloride, sodium isethionate, dihydroxyacetone dimer, sodium benzenesulfonate, benzyltriethylammonium chloride, sodium 1,3-benzenedisulfonate, thiamine, choline chloride, DL-carnitine Hydrochloride, triethanolamine hydrochloride, benzyltrimethylammonium chloride, betaine (glycine betaine), dimethylamine hydrochloride, 1-methyl-2-pyrrolidone, aminoacetonitrile hydrochloride, imi alcohol hydrochloride,
-Picoline-N-oxide, 1- (3-sulfopropyl) pyridinium hydroxybetaine, trimethylamine-N-oxide hydrate, tetraethylammonium chloride, 4-methylimidazole, 4-hydroxymethyl-5-methylimidazole hydrochloride, pyrazole And so on.

Preferred compounds as the hygroscopic compound or the deliquescent compound are the compounds represented by the general formula [1].

In the general formula [1], the substituent represented by R is a lower alkyl group (for example, a methyl group,
Ethyl group, propyl group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), vinyl group, aryl group (eg, phenyl group, p-tolyl group, p-bromophenyl group, etc.), trifluoro Methyl group, alkoxy group (for example, methoxy group, ethoxy group, methoxyethoxy group, etc.), aryloxy group (for example, phenoxy group, p
-Tolyloxy group, etc.), cyano group, sulfonyl group (for example, methanesulfonyl group, trifluoromethanesulfonyl group, p-toluenesulfonyl group, etc.), alkoxycarbonyl group (for example, ethoxycarbonyl group, butoxycarbonyl group, etc.), amino group ( For example, amino group, biscarboxymethylamino group, etc., aryl group (eg, phenyl group, carboxyphenyl group, etc.), heterocyclic group (eg, tetrahydrofurfuryl group, 2-pyrrolidinone-1)
-Yl group, etc.), acyl group (eg, acetyl group, benzoyl group, etc.), ureido group (eg, ureido group, 3-methylureide group, 3-phenylureido group, etc.), thioureido group (eg, thioureido group, 3 -Methylthioureido group, etc.), alkylthio group (for example, methylthio,
An ethylthio group, an arylthio group (eg, a phenylthio group), a heterocyclic thio group (eg, a 2-thienylthio group, a 3-thienylthio, a 2-imidazolylthio group, etc.),
Carbonyloxy group (eg, acetyloxy group, propanoyloxy group, benzoyloxy group, etc.), acylamino group (eg, acetylamino, benzoylamino group, etc.), thioamide group (eg, thioacetamido group, thiobenzoylamino group, etc.) And these also include, for example, sulfo, carboxy, phosphono,
Sulfate group, hydroxy group, mercapto group, sulfino group, carbamoyl group (for example, carbamoyl group, N
-Methylcarbamoyl group, N, N-tetramethylenecarbamoyl group, etc.), sulfamoyl group (eg, sulfamoyl group, N, N-3-oxapentamethyleneaminosulfonyl group, etc.), sulfonamide group (eg, methanesulfonamide, butane A sulfonylaminocarbonyl group (eg, methanesulfonylaminocarbonyl, ethanesulfonylaminocarbonyl group, etc.), an acylaminosulfonyl group (eg, acetamidosulfonyl, methoxyacetamidosulfonyl group, etc.), an acylaminocarbonyl group (eg, Acetamidocarbonyl, methoxyacetamidocarbonyl group, etc.), sulfinylaminocarbonyl group (eg, methanesulfinylaminocarbonyl group, ethanesulfinylaminocarbonyl group, etc.), etc. It may be substituted with a hydrophilic group. M represents an integer of 1 to 5, and when a plurality of Rs are substituted, the Rs may be different from each other. When a plurality of substituents represented by R are adjacently substituted, they are linked to each other to form a new ring;
New quinoline and tetrahydroquinoline rings,
An isoquinoline ring or the like may be formed. Further, these rings may be further substituted with the groups described above.

Some of the pyridine-N-oxide-based compounds described above include some typical deliquescent compounds. Representative examples including these are given below.

1. 5. pyridine-N-oxide 2.3-picoline-N-oxide 3.4-picoline-N-oxide 4.4-methoxypyridine-N-oxide 5.2,5-lutidine-N-oxide 7. Collidine-N-oxide 7.3-Ethyl-4-methylpyridine-N-oxide Quinoline-N-oxide The present invention is not limited to these.

Of the above-mentioned solid hygroscopic compounds and deliquescent compounds, those belonging to another preferred category further include the compounds represented by the aforementioned general formula [2].

In the compound of the general formula [2],
₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a neopentyl group, a cyclopentyl group, Hexyl, cyclohexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, 2-butylhexyl, dodecyl, tetradecyl, hexadecyl, octadecyl, etc. Group), an aromatic group (eg, phenyl group, naphthyl group, etc.) and a heterocyclic group (eg, pyridyl group, furyl group, thienyl group, etc.).

These groups may be further substituted with a suitable substituent. Examples of a suitable substituent include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, Pentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, 2-butylhexyl, dodecyl, tetradecyl, hexadecyl, octadecyl, etc. Linear, branched, or cyclic alkyl group, etc.), an alkoxy group (eg, a methoxy group, an ethoxy group, a propoxy group, etc.), an alkoxycarbonyl group (eg, a methoxycarbonyl group), a carbamoyl group (eg, a methylcarbamoyl group), or an acyl group (For example, acetyl group, benzoyl group, propanoyl group) In addition, alkenyl groups (eg, vinyl group, allyl group, 2-butenyl group, etc.), alkynyl groups (eg, propargyl group, etc.), aralkyl groups (eg, benzyl group, etc.), aromatic groups (eg, phenyl group, A heterocyclic group (eg, a 5- or 6-membered heterocyclic group having at least one atom selected from a nitrogen atom, an oxygen atom, and a sulfur atom), a cyano group, a sulfo group, a carboxyl group, and a nitro group. Group or amino group (for example, unsubstituted amino group, alkylamino group having 1 to 20 carbon atoms, dialkylamino group having 2 to 40 carbon atoms, anilino group, N-alkylanilino group having 7 to 30 carbon atoms), halogen Atom (for example, chlorine atom, bromine atom, etc.), hydroxyl group, ammonium group, sulfamoyl group (for example, unsubstituted sulfamoyl group, di-C 2-40 Ruki Rusuru sulfamoyl group, an alkylsulfamoyl group phenylsulfamoyl group having 1 to 20 carbon atoms, N of 7 to 26 carbon atoms
-Alkyl, N-phenylsulfamoyl group, etc.), ureido group (for example, unsubstituted ureido group, alkyl ureido group having 1 to 20 carbon atoms, dialkyl ureido group having 2 to 40 carbon atoms, phenyl ureido group, etc.), amidino Groups, hydrazino groups, hydroxyamino groups, guanidino groups, mercapto groups, phosphono groups, and phosphine groups.
R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R _4, or R ₄ and R ₁ may form an aromatic ring or a heterocyclic ring.

X is a counter ion, which represents a halogen or an organic acid. n represents the valence of the counter ion and is an integer from 1 to 4. Halogen refers to fluorine, chlorine, bromine, iodine and astatine. The organic acid is a generic term for all acidic organic compounds, and includes carboxylic acid, sulfonic acid, sulfinic acid, phenol, enol, thiophenol, imide, oxime, aromatic sulfonamide, primary and secondary nitro compounds It is an organic compound having a functional group and a bone nucleus.

The following are typical organic acids, but the present invention is not limited to these.

For example, oxalic acid, tartaric acid, benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, benzenesulfinic acid, p-toluenesulfinic acid, phenol, Picric acid, acetylacetone, thiophenol, succinimide, glutarimide, phthalimide, benzaldoxime, benzenesulfonamide and the like.

Among these compounds, salts obtained by neutralizing an amine compound with an acid are included to form preferred compounds. Particularly, chloride or hydrochloride is preferable.

Examples of preferred compounds represented by the general formula [2], including these, include the following.

1.2-chloroethylamine hydrochloride 2. Tris (hydroxymethyl) aminoethane hydrochloride Phenyltrimethylammonium chloride 4. ethylamine hydrochloride Benzyltriethylammonium chloride 6. DL-carnitine hydrochloride 7. Triethanolamine hydrochloride 8. benzyltrimethylammonium chloride Dimethylamine hydrochloride10. Aminoacetotrile hydrochloride 11. Alcohol hydrochloride 12.4-Hydroxymethyl-5-methylimidazole hydrochloride Preferred solid and hygroscopic organic compounds in the present invention further include azoles. These azoles refer to compounds having a azole ring structure in the molecule of a 5-membered heterocyclic ring having two or more hetero atoms in the ring and at least one of the hetero atoms being a nitrogen atom. . Representative azoles are shown below, but the present invention is not limited thereto.

Imidazole, oxazole, thiazole, selenazole, pyrazole, isoxazole, isothiazole, 1,2,3-triazole, 1,2,5
-Triazole, 1,2,4-triazole, 1,3
4-triazole, 1,2,3-oxadiazole,
1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3
-Thiadiazole, 1,2,4-thiadiazole, 1,
2,5-thiadiazole, 1,3,4-thiadiazole, 1,2,3,4-tetrazole, 1,2,3,4-
Oxatriazole, 1,2,3,5-thiatriazole, indazole, benzimidazole, benzotriazole, benzothiazole, benzothiazoline, and purine.

Among these compounds, particularly useful compounds are isethionic acid, 3-aminopyridine, dihydroxyacetone dimer, 1- (3-sulfopropyl) pyridinium hydroxybetaine, pyridine-N-oxide, tris ( (Hydroxymethyl) aminoethane, ethylamine, thiamine, choline, benzyltrimetrimethylamine, tetraethylamine, pyrazole or 4-hydroxymethyl-5-methylimidazole.

These compounds of the present invention are most effective when used simultaneously with the compound represented by the above general formula [3] as a high boiling organic solvent.

Examples of the high-polarity and high-boiling organic solvent represented by the general formula [3] in the present invention include: 1. ethylene glycol 2. Diethylene glycol Triethylene glycol4. Tetraethylene glycol5. Polyethylene glycol 200 6. 6. polyethylene glycol 300 Compounds such as polyethylene glycol 600. The present invention is not limited to these compounds.

The most preferred of these is ethylene glycol.

The general formula [3] used in the ink of the present invention.
Is preferably from 5% to 50% based on the total weight of the ink.

These high-boiling organic solvents may be used in combination with liquid high-boiling organic solvents which have been used so far. However, in that case, 50% by weight or more, preferably 80% by weight or more, more preferably 90% by weight of the compound having the general formula [3] of the entire high polar high boiling point organic solvent contained in the ink. Is preferred.

Among them, those containing ethylene glycol as a high-boiling organic solvent in an amount of 50% by weight or more, preferably 80% by weight or more, more preferably 90% by weight of the high-polarity high-boiling point organic solvent contained in the whole ink are preferred.

By using these high-boiling organic solvents in combination,
It is possible to provide an ink jet recording liquid that has no clogging of the ink head, has excellent ejection stability, has good drying properties when recorded on a recording medium, and has excellent performance without ink bleeding.

The ink jet recording liquid of the present invention exerts its effect particularly when the ink droplets are small. In the present invention, the effect is great when used in an ink jet ejection apparatus having a minimum droplet amount of 10 pl or less. Among them, preferred is one used for an ink-jet ejection device having a minimum droplet amount of 7 pl or less, and more preferred is use of an ink-jet ejection device having a minimum droplet amount of 5 pl or less.

By using these ink jet recording liquids, it is possible to obtain high-definition fine droplets, which are suitable for reproducing characters and images, have good ejection stability, and have excellent quality without printing or image bleeding. An inkjet recording method can be provided.

The minimum droplet volume in the present invention refers to the droplet volume of the ink ejected from the nozzle tip at 25 ° C. If the droplet size is variable, the minimum droplet volume is Point.

In the present invention, an ink jet ink containing a water-soluble dye as a coloring agent is preferable. The water-soluble dye includes a water-soluble direct dye, an acid dye,
These are selected from reactive dyes and basic dyes, and these may be used alone or in combination of two or more. These dyes are used by dissolving them in a solvent appropriately selected and used as desired. The following are representative dyes, but the present invention is not limited thereto.

<Direct Dye> C.I. I. Direct Yellow 1, 4, 8, 11, 1
2, 24, 26, 27, 28, 33, 39, 44, 5,
0, 58, 85, 86, 100, 110, 120, 13
2, 142, 144 C.I. I. Direct red 1,2,4,9,11,
13, 17, 20, 23, 24, 28, 31, 33, 3,
7, 39, 44, 47, 48, 51, 62, 63, 7
5, 79, 80, 81, 83, 89, 90, 94, 9
5, 99, 220, 224, 227, 243 C.I. I. Direct blue 1,2,6,8,15,
22, 25, 71, 76, 78, 80, 86, 87, 9
0, 98, 106, 108, 120, 123, 163,
165, 192, 193, 194, 195, 196, 1
99, 200, 201, 202, 203, 207, 23
6, 237 C.I. I. Direct Black 2, 3, 7, 17, 1
9, 22, 32, 38, 51, 56, 62, 71, 7
4, 75, 77, 105, 108, 112, 117, 1
54 <Acid dye> C.I. I. Acid Yellow 2, 3, 7, 17, 19,
23, 25, 29, 38, 42, 49, 59, 61, 7
2,99 C.I. I. Acid Orange 56, 64 C.I. I. Acid Red 1, 8, 14, 18, 2
6, 32, 37, 42, 52, 57, 72, 74,
80, 87, 115, 119, 131, 133, 13
4, 143, 154, 186, 249, 254, 256 C.I. I. Acid Violet 11, 34, 75 C.I. I. Acid Blue 1, 7, 9, 29, 87,
126, 138, 171, 175, 183, 234, 2
36, 249 C.I. I. Acid Green 9, 12, 19, 27, 4
1 C. I. Acid Black 1, 2, 7, 24, 26,
48, 52, 58, 60, 94, 107, 109, 11
0, 119, 131, 155 <Reactive dye> I. Reactive yellow 1,2,3,13,1
4, 15, 17, 37, 42, 76, 95, 168, 1
75; I. Reactive Red 2, 6, 11, 21, 2
2, 23, 24, 33, 45, 111, 112, 11
4, 180, 218, 226, 228, 235; I. Reactive Blue 7, 14, 15, 18,
19, 21, 25, 38, 49, 72, 77, 176,
203, 220, 230, 235; I. Reactive Orange 5, 12, 13, 3
5, 95; I. Reactive Brown 7, 11, 33, 3
7, 46; I. Reactive green 8, 19; I. Reactive Violet 2, 4, 6, 8,
21, 22, 25; I. Reactive Black 5, 8, 31, 39 <Basic dye> C.I. I. Basic Yellow 11, 14, 21, 32 C.I. I. Basic Red 1, 2, 9, 12, 13 C.I. I. Basic violet 3, 7, 14 C.I. I. Basic Blue 3, 9, 24, 25 Other dyes that can be used in the ink of the present invention include chelate dyes and azo dyes used in so-called silver dye bleaching light-sensitive materials (for example, Cibachrome manufactured by Ciba Geigy). I can do it.

The chelating dyes are described, for example, in British Patent 1,077,484.

With respect to the azo dyes of the silver dye bleaching photosensitive material, for example, British Patent Nos. 1,039,458 and
004,957, 1,077,628 and U.S. Pat. No. 2,612,448.

The content of the water-soluble dye used in the ink of the present invention is preferably 1 to 10% by weight based on the total weight of the ink.

The ink of the present invention may also contain an organic solvent in addition to the high boiling point solvent. These organic solvents include alkyl alcohols having 1 to 4 carbon atoms (for example, methyl alcohol, ethyl alcohol, and the like). n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, etc., amides (eg, dimethylformamide, dimethylacetamide, etc.), ketones or keto alcohols (eg, acetone, Acetone alcohols, etc.), ethers (e.g., tetrahydrofuran, dioxane, etc.), alkylene glycols having an alkylene group containing 3 to 6 carbon atoms (e.g., propylene glycol, butylene glycol, 1,2,6-hexanetriol, Methiodide glycol, hexylene glycol and the like), glycerin, lower alkyl ethers of polyhydric alcohols (ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether,
Triethylene glycol monomethyl (or ethyl) ether and the like).

The content of the organic solvent in the ink is less than 5% by weight based on the total weight.

In the present invention, pigments and disperse dyes can be used as colorants. These pigments and disperse dyes are used by dispersing in a solvent that is appropriately selected and used as needed. Representative examples are described below, but the present invention is not limited to these.

The disperse dyes preferred in the present invention are C.I. I. D
ispersel Yellow 3, 4, 5, 7, 9,
13, 24, 30, 33, 34, 42, 44, 49, 5
0, 51, 54, 56, 58, 60, 63, 64, 6
6, 68, 71, 74, 76, 79, 82, 83, 8
5, 86, 88, 90, 91, 93, 98, 99, 10
0, 104, 114, 116, 118, 119, 12
2, 124, 126, 135, 140, 141, 14
9, 160, 162, 163, 164, 165, 17
9, 180, 182, 183, 186, 192, 19
8, 199, 202, 204, 210, 211, 21
5, 216, 218, 224; I. Dispers
e Orange 1, 3, 5, 7, 11, 13, 1
7, 20, 21, 25, 29, 30, 31, 32, 3,
3, 37, 38, 42, 43, 44, 45, 47, 4
8, 49, 50, 53, 54, 55, 56, 57, 5
8, 59, 61, 66, 71, 73, 76, 78, 8
0, 89, 90, 91, 93, 96, 97, 119, 1
27, 130, 139, 142; I. Disper
se Red 1, 4, 5, 7, 11, 12, 13, 1
5, 17, 27, 43, 44, 50, 52, 53, 5
4, 55, 56, 58, 59, 60, 65, 72, 7
3, 74, 75, 76, 78, 81, 82, 86, 8
8, 90, 91, 92, 93, 96, 103, 105,
106, 107, 108, 110, 111, 113, 1
17, 118, 121, 122, 126, 127, 12
8, 131, 132, 134, 135, 137, 14
3, 145, 146, 151, 152, 153, 15
4, 157, 159, 164, 167, 169, 17
7, 179, 181, 183, 184, 185, 18
8, 189, 190, 191, 192, 200, 20
1, 202, 203, 205, 206, 207, 21
0, 221, 224, 225, 227, 229, 23
9, 240, 257, 258, 277, 278, 27
9, 281, 288, 298, 302, 303, 31
0, 311, 312, 320, 324, 328;
I. Disperse Violet 1, 4, 8, 2
3, 26, 27, 28, 31, 33, 35, 36, 3
8, 40, 43, 46, 48, 50, 51, 52, 5
6, 57, 59, 61, 63, 69, 77; I. D
isperse Green 9; I. Dispe
rs Brown 1, 2, 4, 9, 13, 19;
C. I. Disperse Blue 3, 7, 9, 1
4, 16, 19, 20, 26, 27, 35, 43, 4
4, 54, 55, 56, 58, 60, 62, 64, 7
1, 72, 73, 75, 79, 81, 82, 83, 8
7, 91, 93, 94, 95, 96, 102, 106,
108, 112, 113, 115, 118, 120, 1
22, 125, 128, 130, 139, 141, 14
2,143,146,148,149,153,15
4, 158, 165, 167, 171, 173, 17
4, 176, 181, 183, 185, 186, 18
7, 189, 197, 198, 200, 201, 20
5, 207, 211, 214, 224, 225, 25
7, 259, 267, 268, 270, 284, 28
5, 287, 288, 291, 293, 295, 29
7, 301, 315, 330, 333; I. Dis
perse black 1, 3, 10, 24; and the like.

The pigments preferred in the present invention include carbon black pigments (CI Pigment Bla).
ck 7); I. Pigment Yellow
12, 13, 14, 16, 17, 73, 74, 75, 8
3, 108, 109, 110, 180, 182;
I. Pigment Red 5, 7, 12, 112,
123, 168, 184, 202; I. Pigme
nt Blue 1, 2, 3, 15: 3, 16, 22,
60; I. Vat Blue 4, 60; When red, green, blue, or intermediate colors are required in addition to the above, it is preferable to use the following pigments alone or in combination.

C. I. Pigment Red 20
9, 224, 177, 194; I. Pigment
Orange 43; I. Vat Violet
3; I. Pigment Violet 19,
23, 37; I. Pigment Green 3
6, 7; I. Pigment Blue 15, 6
Is used.

The pigment and the disperse dye used in the ink according to the present invention are mixed with a dispersant and other necessary additives according to various desired purposes and dispersed by a disperser.

As the disperser, a conventionally known ball mill, sand mill, line mill, high-pressure homogenizer and the like can be used.

As the dispersant, a surfactant is used.
As the surfactant used in the present invention, any of cationic, anionic, amphoteric and nonionic can be used.

Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts and the like. Examples of the anionic surfactant include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acylglutamate, acylated peptide, alkyl sulfonate, Alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfo acetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil,
Higher alcohol sulfates, secondary higher alcohol sulfates, alkyl ether sulfates, secondary higher alcohol ethoxy sulfates, polyoxyethylene alkyl phenyl ether sulfates, monoglyculfate, fatty acid alkylolamide sulfates, alkyl Examples thereof include ether phosphoric acid ester salts and alkyl phosphoric acid ester salts.

Examples of the amphoteric surfactant include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like.

Examples of the nonionic activator include polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene alkyl ether,
Polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester And fatty acid alkanolamides, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkylamine oxides, acetylene glycol, acetylene alcohol and the like.

In the ink of the present invention, a surfactant can be used to accelerate the penetration of the ink droplets after ejection into the medium. The surfactant that can be used is not particularly limited as long as it has no adverse effect such as storage stability on the ink, and the same surfactants as those used as the dispersant described above can be used. Can be used.

In the present invention, an electric conductivity adjusting agent can be used. Examples of the electric conductivity adjusting agent include potassium chloride, ammonium chloride, sodium sulfate, and the like.
There are inorganic salts such as sodium nitrate and sodium chloride, and water-soluble amines such as triethanolamine.

In the ink of the present invention, ejection stability,
Depending on the purpose of printhead and ink cartridge compatibility, storage stability, image storability, and other performance improvements,
Further, a viscosity adjuster, a specific resistance adjuster, a film forming agent, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, a rust inhibitor, a preservative, and the like can be added.

The ink of the present invention can be used for any on-demand type ink jet recording system. Examples of the on-demand type include an electro-mechanical conversion type (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shared mode type, a shared wall type, etc.), and an electro-thermal conversion type (for example,
Thermal inkjet type, bubble jet type, etc.), electrostatic suction type (eg, electric field control type, slit jet type, etc.), and discharge type (eg, spark jet type, etc.)
And the like can be given as specific examples.

[0085]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to the embodiments in the examples.

Example 1 The viscosity of the ink composition was adjusted to 4.5 cp by mixing a liquid A and a liquid B having the following composition at an appropriate ratio. 1 to
30 were created.

Solution A Dye (described in Table 1 and Table 2) 5.0% Proxel GXL (D) 0.1% from Zeneca Compound (described in Table 1 and Table 2) 30% High boiling organic solvent (Table 1 and Table 2) (Described in Table 2) (Described in Table 1 and Table 2) Ion-exchanged water Remaining liquid B Dye (same as Liquid A) 5.0% Zeneca Proxel GXL (D) 0.1% High boiling organic solvent (with Liquid A) (Same as Liquid A) Ion-exchanged water Remainder The number of discharge nozzles = 64, the nozzle diameter = 22 μm, and the discharge frequency = 30 KHZ. The discharge was performed using a piezo-type inkjet head, and the discharge speed was measured. The droplet volume at this time is 7
pl.

The structure of the ink jet head is as shown in FIG. FIG. 1 exemplifies a head having five discharge nozzles for explanation. A piezo element P for discharging ink droplets by displacement of the piezo element P is provided on the head corresponding to each discharge nozzle. Also,
A driver IC represented by D, which supplies a driving signal and a heating signal to the piezo element P, forms an ink flow path (ink pool).
Is placed on top.

A thermistor S is provided on the discharge nozzle near the piezo element, and constitutes a temperature measuring means. The ink jet head receives the supply of ink from the ink tank T. (A) is a view of this as viewed from above. (B) shows a cross-sectional view along AA.

First, continuous ejection was performed at a temperature of 24 ° C. and a humidity of 25%, and the driving voltage of the piezo element was changed to adjust the droplet speed to 8 m / s.

Thereafter, after the ejection was stopped for a certain period of time shown in Tables 1 and 2, ejection was performed again, and the speed of the first ejected droplet after the re-ejection was measured. The droplet speed was determined from the time after the ejection and the moving distance by a stroboscope linked to the ejection.

Also, Konica Photo Jet Paper Q
Only one dot was ejected onto P, and bleeding was visually evaluated from the change in dot shape after storage for 3 days at 24 ° C. and 80% humidity.

The evaluation of bleeding was evaluated by the following: ○ good without bleeding around dots; × bleeding around dots. The results are shown in Tables 1 and 2.

[0094]

[Table 1]

[0095]

[Table 2]

The ink of the present invention has a smaller decrease in the ejection speed than the ink of the comparative example containing a solid having no hygroscopicity.
Also, it can be seen that dot bleeding is smaller than in the comparative example using only liquid.

Example 2 Ink composition no. 1 to No. 30, the number of ejection nozzles = 64, nozzle diameter = 25 μm, ejection frequency = 30 KH
An experiment was performed in the same manner as in Example 1 except that the piezo-type inkjet tester Z was used and the pause time was 2.0 seconds. The droplet volume at this time was 10 pl. Table 3 shows the results
Shown in

[0098]

[Table 3]

It can be seen that the ink of the present invention has less decrease in ejection speed and less bleeding than the ink of the comparative example.

Example 3 Ink composition no. 1 to No. No. of ejection nozzles = 64 Nozzle diameter = 25 μm Discharge frequency = 30 KH
An experiment was performed in the same manner as in Example 1 except that the piezo system inkjet tester Z was used and the rest time was set to 0.2 seconds. The droplet volume at this time was 10 pl. Table 4 shows the results
Shown in

[0101]

[Table 4]

Under these conditions, it can be seen that the ink of the present invention has less decrease in ejection speed and less bleeding than the ink of the comparative example.

[0103]

According to the present invention, it is possible to provide an ink jet ink having good ejection stability without performing preliminary ejection for a long time in a low humidity environment, and to obtain an ink suitable for high definition recording.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an inkjet head.

[Explanation of symbols]

 D Driver IC P Piezo element S Thermistor T Ink tank

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 FC01 2H086 BA52 BA55 BA59 BA62 4J039 AE07 BA04 BA29 BC05 BC07 BC09 BC10 BC12 BC16 BC19 BC32 BC33 BC34 BC36 BC37 BC43 BC44 BC46 BC47 BC50 BC51 BC52 BC53 BC54 BC55 BC56 BC65 BE01 BE03 BE04 BE05 BE06 BE08 BE12 BE15 CA03 CA06 EA10 EA11 EA15 EA16 EA17 EA19 EA41 EA42 EA44 EA47 GA24

Claims (12)

[Claims] 1. An on-demand ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent and a hygroscopic solid organic compound. 2. An on-demand type ink jet printer characterized by containing at least water, a colorant, a high boiling organic solvent and an organic compound which is deliquescent at 25 ° C., 50% humidity and 1 atm. Recording liquid. 3. An on-demand type ink jet recording liquid comprising at least water, a colorant, a high boiling point organic solvent and a compound represented by the general formula [1]. Embedded image [Wherein, R represents a hydrogen atom or a substituent, and m represents 1 to 4
Represents an integer. ] 4. An on-demand ink jet recording liquid comprising at least water, a colorant, a high boiling point organic solvent and a compound represented by the general formula [2]. Embedded image [Wherein, R ₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom,
Represents a substituted or unsubstituted alkyl group, aromatic group, or heterocyclic group. R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R _4, or R ₄ and R ₁ may form an aromatic ring or a heterocyclic ring. X represents a halogen or an organic acid residue. n is an integer of 1 to 4. ] 5. An on-demand ink jet recording liquid comprising at least water, a colorant, a high-boiling organic solvent, and a compound having an azole structure. 6. It is characterized by containing at least water, a colorant, a high boiling organic solvent and isethionic acid, 3-aminopyridine, dihydroxyacetone dimer or 1- (3-sulfopropyl) pyridinium hydroxybetaine. On-demand recording liquid for inkjet. 7. At least water, a colorant, a high boiling organic solvent and pyridine-N-oxide, tris (hydroxymethyl) aminoethane, ethylamine, thiamine, choline, benzyltrimetrimethylamine, tetraethylamine, pyrazole or 4-hydroxymethyl- An on-demand ink jet recording liquid comprising 5-methylimidazole. 8. The on-demand type ink jet recording liquid according to claim 1, wherein 50% by weight or more of the high boiling point organic solvent is a compound represented by the general formula [3]. Formula (3) _{H- (OCH 2 CH 2) l} -OH [l wherein represents an integer of 1 to 50. ] 9. The on-demand ink jet recording liquid according to claim 1, wherein 50% by weight or more of the high boiling organic solvent is ethylene glycol. 10. An on-demand ink jet recording apparatus, wherein the on-demand ink jet recording liquid according to claim 1 is used in an ink jet apparatus having a minimum droplet volume of 10 pl or less. Recording method. 11. An on-demand type ink-jet, wherein the on-demand type ink-jet recording liquid according to claim 1 is used in an ink-jet discharge device having a minimum droplet volume of 7 pl or less. Recording method. 12. The on-demand type ink jet recording apparatus according to claim 1, wherein the on-demand type ink jet recording liquid is used in an ink jet apparatus having a minimum droplet volume of 5 pl or less. Recording method.