JP2007217472A - Liquid composition for inkjet, ink set for inkjet, ink tank for inkjet, method of inkjet-recording, and device of inkjet-recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid composition for an inkjet without having occlusion at the tip end of a nozzle of the inkjet, an ink set for the inkjet by using the same, a method of inkjet-recording and a device of inkjet-recording. <P>SOLUTION: This liquid composition containing at least an agglomerating agent, water soluble solvent, a surfactant and water is characterized by having ≥0.4 value of (a×b) on taking (a) S/m dielectric constant and and (b) mPa s viscosity, and containing ≥1 kind of the water soluble solvent having ≤52 mN/m surface tension of 5% aqueous solution of the same. The ink set for the inkjet by using the same, and the method of the inkjet-recording and the device of the inkjet-recording by utilizing the ink set are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet liquid composition, an inkjet ink set, an inkjet liquid composition tank, an inkjet ink tank, an inkjet recording method, and an inkjet recording apparatus.

  An ink jet system that discharges ink from an ink discharge port formed by a nozzle, a slit, a porous film, and the like is used in many printers because it is small and inexpensive. Among these ink jet systems, the piezoelectric ink jet system that ejects ink using deformation of piezoelectric elements and the thermal ink jet system that ejects ink using the boiling phenomenon of ink due to thermal energy are excellent in high resolution and high speed printability. Has characteristics.

In recent years, in obtaining high-definition full-color printing, obtaining high image density, no blur of images, and no blur between colors have become important issues.
Against this background, in recent inkjet recording, recording methods using a liquid composition other than ink (hereinafter referred to as “treatment liquid”) are becoming popular with the aim of further improving ejection stability and image quality.

Water is used as the main component of the solvent of the ink and the treatment liquid. In general, water has a high vapor pressure and evaporates with time. Therefore, it is known that the ink viscosity increases when the ink is left for a long time. In inkjet, since the nozzle diameter for ejecting ink and processing liquid is small, the change in the state of the ink and processing liquid has a large effect on the jetting property of the liquid, and the ink and processing liquid are filled in the head for a long time. If left unattended, there is a tendency for image quality deterioration such as non-ejection in which ink and processing liquid are not ejected and directionality failure in which the ejection direction is bent.
In particular, the treatment liquid tends to be clogged more easily than the ink. This is presumed to be because the treatment liquid contains a large amount of a flocculant, so that precipitation of the flocculant, the surfactant, and the like is likely to occur during the evaporation of moisture.

  For the purpose of improving the clogging of the inkjet head, an ink containing a coloring material, a plurality of resins, an aqueous solvent, and water and specifying the compatibility of the resin and the coloring material with a solubility parameter (SP value) is disclosed. (See Patent Document 1).

However, the target of clogging is ink, and the constituent components of the treatment liquid are completely different. In fact, no effective method has been disclosed for the treatment liquid.
JP 2003-238855 A

  Accordingly, an object of the present invention is to provide an ink jet liquid composition that is free from clogging at the nozzle tip of an ink jet head, and an ink jet ink set using the same. Another object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus using the ink set.

In view of the above circumstances, the present inventors have conducted extensive research and found that the above problems can be solved, thereby completing the present invention.
That is, the present invention is achieved by the following means.

<1> A liquid composition containing at least a flocculant, a water-soluble solvent, a surfactant, and water, wherein the value of a × b is 0 when the conductivity is aS / m and the viscosity is bmPa · s. 4. A liquid composition for inkjet, comprising one or more of 4 or more, wherein the surface tension of a 5% aqueous solution of the water-soluble solvent is 52 mN / m or less.

<2> The water-soluble solvent having a surface tension of 52 mN / m or less is at least one selected from the following general formula (1) and the following general formula (2). A liquid composition for inkjet.
Formula _{(1) C n H (2n} + 2-m) - (OH) m
Formula _{(2) C p H (2p} + 1) - (C q H 2q O q) r -OH
(In general formula (1), n represents 4-8, m represents 2-3. In general formula (2), p represents 1-6, q represents 2-4, r is 1 Represents 4)

<3> The liquid composition for ink jet according to <1> or <2>, wherein the addition amount of the surfactant is 1.0% by mass or more.
<4> The inkjet according to any one of <1> to <3>, wherein the addition amount of a water-soluble solvent having a surface tension of 52 mN / m or less is 3.0% by mass or more. Liquid composition.

<5> The liquid composition for ink jet according to any one of <1> to <4>, further comprising a water-soluble solvent having a surface tension of more than 52 mN / m.
<6> The liquid composition for ink jet according to claim 5, wherein the total amount of the water-soluble solvent having a surface tension of 52 mN / m or less and 52 mN / m or more is 10% by mass or more.

<7> The mass ratio when the flocculant and the surfactant are mixed is 1: 100 to 1: 0.1, according to any one of the above <1> to <6>, Liquid composition for inkjet.
<8> The liquid composition for ink jet according to any one of <1> to <7>, wherein the amount of water added is 75% by mass or less.

<9> The liquid composition for ink jet according to any one of <1> to <8>, wherein the surface tension is 25 to 40 mN / m.
<10> An inkjet ink set comprising an inkjet ink and an inkjet liquid composition containing a colorant, a water-soluble solvent, a surfactant and water, wherein the inkjet liquid composition is the above <1> to < An ink-jet ink set, which is the ink-jet liquid composition according to any one of 9>.

<11> The water-soluble solvent and surfactant contained in the ink-jet ink are the same as the water-soluble solvent and surfactant contained in the ink-jet liquid composition. Ink set for inkjet.
<12> An inkjet ink tank containing the inkjet ink and the inkjet liquid composition of the inkjet ink set according to <10> or <11>.

<13> An inkjet recording method using an inkjet ink set, wherein the inkjet ink set is the inkjet ink set according to <10> or <11>, and the inkjet ink and the inkjet liquid. An ink jet recording method comprising forming an image by applying the composition on a recording medium so as to contact each other.
<14> An ink jet recording apparatus comprising a recording head for discharging each liquid in the ink jet ink set to a recording medium, wherein the ink jet ink set is the ink jet recording apparatus according to <10> or <11>. An ink jet recording apparatus comprising an ink set.

ADVANTAGE OF THE INVENTION According to this invention, the liquid composition for inkjet which is not clogged with an inkjet head can be provided.
In addition, according to the present invention, it is possible to provide an ink jet ink set using the ink jet liquid composition, which is capable of forming an image having no blur and a high optical density.
Furthermore, according to the present invention, an ink jet recording method and an ink jet recording apparatus using the ink set can be provided.

Hereinafter, the present invention will be described in detail.
(Ink set for inkjet)
The ink-jet ink set of the present invention includes an ink-jet ink (hereinafter also referred to as “ink”) and an ink-jet liquid composition (hereinafter referred to as “liquid composition”) having an action of aggregating or insolubilizing the ink-jet ink. It is also configured to include a product.
Further, by using the ink set having the liquid composition, an image having a high optical density without a nozzle failure of the liquid composition, a poor directivity, and a good image quality without bleeding can be obtained with an ink jet recording apparatus. it can.

(Liquid composition for inkjet)
Conventionally, in order to obtain an image quality improvement effect, a method of adding an electrolyte as a flocculant to a liquid composition has been known. However, in this method, nozzle non-ejection and deterioration of directionality may be problematic. This was considered to be caused by the precipitation of the surfactant by increasing the electrolyte concentration in the system.
As a result of studying to solve this problem, it was found that nozzle non-ejection and poor directionality can be prevented by adding a water-soluble solvent having a surface tension within a specific range. The liquid composition according to the present invention was able to obtain good image quality even in terms of optical density and bleeding.
Although the mechanism of the improvement is not clear, it is considered that in the conventional method, dehydration of the hydrophilic group of the surfactant occurs and the surfactant becomes insoluble by increasing the electrolyte concentration in the liquid composition. Therefore, it is considered that by using a water-soluble solvent having a low surface tension, it is possible to increase the solubility of the dehydrated surfactant in water and prevent precipitation.
Hereinafter, the liquid composition will be described in detail.

The liquid composition of the present invention contains at least a flocculant, a water-soluble solvent, a surfactant, and water, and has an a × b value (hereinafter referred to as “aS / m” and a viscosity of “bmPa · s”). , “Ab value”) is 0.4 or more, and the water-soluble solvent contains one or more water-soluble solvents in which the surface tension of a 5% aqueous solution is 52 mN / m or less.
By using a liquid composition having specific physical properties, including the water-soluble solvent, it is possible to effectively prevent the surfactant from precipitating on the nozzle surface during high-temperature storage or water evaporation. It is possible to improve the discharge failure and discharge directionality failure of the liquid composition.

In the liquid composition of the present invention, as described above, the product a × b of the electrical conductivity a (S / m) and the viscosity b (mPa · s) is required to be 0.4 or more, preferably 0. 4 or more and 50 or less, more preferably 0.5 or more and 25 or less, and particularly preferably 0.5 or more and 10 or less.
If the ab value is less than 0.4, sufficient optical density could not be obtained.
On the other hand, when the ab value exceeds 50, the surfactant is deposited during the evaporation of water, resulting in nozzle non-ejection and ejection direction failure, and image quality may be deteriorated.

The value of the conductivity a (S / m) is not particularly limited, but is preferably 0.1 to 10 (S / m), more preferably 0.1 from the viewpoint of achieving both optical density and clogging. 1 to 5 (S / m), particularly preferably 0.2 to 2 (S / m).
By setting it as the said range, it becomes possible to make an optical density and clogging compatible, and it is preferable.
The conductivity was measured with MPC227 (pH / Conductivity Meter, manufactured by METTLER TREND).

The conductivity of the liquid composition can be adjusted, for example, as follows.
The liquid composition contains alkali metal compounds such as potassium hydroxide, sodium hydroxide and lithium hydroxide, ammonium hydroxide, triethanolamine, diethanolamine, ethanolamine, 2-amino-2-methyl-1-propanol and the like. It can be prepared by appropriately adding a compound of an alkaline earth metal such as a nitrogen compound or calcium hydroxide, an acid such as sulfuric acid, hydrochloric acid or nitric acid, a strong acid or weak alkali salt such as ammonium sulfate, or the like.

Although it does not specifically limit as a value of the said viscosity b (mPa * s), Preferably it is 1.5-30 (mPa * s), More preferably, it is 2-15 (mPa * s).
If it is less than 1.5 (mPa · s), the long-term storage stability may deteriorate, and if it exceeds 30 (mPa · s), the discharge stability of the liquid composition may be lowered.

Here, as the viscosity, a value measured using a rheomat 115 (manufactured by Contraves) as a measuring device, a measurement temperature of 23 ° C., and a shear rate of 1400 s ⁻¹ was adopted.
The viscosity can be adjusted as follows, for example.
It can be prepared by appropriately adding a flocculant or a water-soluble solvent.

  Then, the structure of the liquid composition in this invention is demonstrated in detail.

<Water-soluble solvent>
The water-soluble solvent in the liquid composition of the present invention needs to contain one or more water-soluble solvents in which the surface tension of a 5% aqueous solution is 52 mN / m or less.
Especially, the water-soluble solvent whose said surface tension is 20 mN / m or more and 52 mN / m or less is preferable, and the water-soluble solvent which is 25 mN / m or more and 40 mN / m or less is more preferable.
In the case of a water-soluble solvent in which the surface tension of the 5% aqueous solution exceeds 52 mN / m, when the compatibility between the water-soluble solvent and the surfactant is poor and the surfactant is dehydrated, the surfactant is It will precipitate as a solid. As a result, solid matter deposition during high-temperature storage or clogging on the nozzle surface during water evaporation causes nozzle non-ejection and poor directionality. In the so-called two-component printing method using ink and processing liquid, bleeding due to ink that cannot contact the processing liquid and image quality degradation occur.

  Here, as the surface tension, a value measured in an environment of 23 ° C. and 55% RH using a Wilhelmy type surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.) was adopted.

The water-soluble solvent is not particularly limited as long as it contains one or more water-soluble solvents having a surface tension (γ) of 5% aqueous solution of 52 mN / m or less as described above. it can.
Among the above, the water-soluble solvent having a surface tension (γ) of the 5% aqueous solution of 52 mN / m or less is preferably one or more selected from the following general formula (1) and general formula (2). .
Formula _{(1) C n H (2n} + 2-m) - (OH) m
Formula _{(2) C p H (2p} + 1) - (C q H 2q O q) r -OH

  In said general formula (1), n represents 4-8, Preferably it is 4-6. M represents 2 to 3, and is preferably 2.

  Specific examples of the general formula (1) include 1,2-hexanediol (γ: 29.1 mN / m), 1,6-hexanediol (γ: 48.1 mN / m), 2,5-hexanediol ( and polyhydric alcohols such as γ: 50.9 mN / m), 1,2-pentanediol (γ: 45.4 mN / m), 1,5-pentanediol (γ: 45.6 mN / m).

  Moreover, in said general formula (2), p represents 1-6, q represents 2-4, r represents 1-4, More preferably, p is 2-4, q is 2-3, r Is 1-3.

  Specific examples of the general formula (2) include diethylene glycol monobutyl ether BCBT (γ: 36.3 mN / m), propylene glycol monoethyl ether (γ: 50.5 mN / m), dipropylene glycol monobutyl ether (γ: 28. And polyhydric alcohol derivatives such as 8 mN / m).

  Examples of the water-soluble solvent include 1,2-hexanediol (γ: 29.1 mN / m) and 1,2-pentanediol (γ: 45.4 mN / m) among the general formulas (1) and (2). 1,6-hexanediol (γ: 48.1 mN / m) and diethylene glycol monobutyl ether BCBT (γ: 36.3 mN / m) can be preferably used.

As the water-soluble solvent in the present invention, polyhydric alcohols other than those described above, polyhydric alcohol derivatives other than those described above, nitrogen-containing solvents, alcohols, sulfur-containing solvents, and the like can be used.
Other polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol (1,2-butanediol, 1,3-butanediol, 1,4-butanediol), triethylene glycol, 1,2 , 6-hexanetriol, glycerin, TMP, and the like.
Examples of other polyhydric alcohol derivatives include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.
Examples of nitrogen-containing solvents include 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, and triethanolamine. Examples of alcohols include alcohols such as ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol. Examples thereof include thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like.
In addition, propylene carbonate, ethylene carbonate, or the like can be used.

As the water-soluble solvent used in the liquid composition, a 5% aqueous solution having a surface tension of 52 mN / m or less may be used alone, but two or more kinds may be used in combination.
When using 2 or more types together, it is preferable to contain at least a water-soluble solvent in which the surface tension of a 5% aqueous solution exceeds 52 mN / m.
Examples of the water-soluble solvent include those exemplified as the water-soluble solvent having a suitable surface tension.

The addition amount of the water-soluble solvent having a surface tension of 5% aqueous solution of 52 mN / m or less in the present invention is not particularly limited, but is preferably 3% by mass or more, more preferably 3% in the liquid composition. It is not less than 20% by mass and particularly preferably not less than 3% by mass and not more than 10% by mass.
When the addition amount is less than 3% by mass, the surfactant may be precipitated, and when it exceeds 20% by mass, the optical density may be lowered.

The total addition amount of the water-soluble solvent when the surface tension of the 5% aqueous solution contains a water-soluble solvent having a surface tension of 52 mN / m or less and more than 52 mN / m is preferably 10% by mass or more in the liquid composition. Preferably it is 10 mass% or less and 40 mass% or less.
When the amount of the water-soluble solvent in the liquid composition is less than 10% by mass, the compatibility between the surfactant and the water-soluble solvent having a surface tension (γ) of a 5% aqueous solution of 52 mN / m or less is sufficient. However, when the amount is more than 40% by mass, the aggregating agent may be precipitated and clogging may be worsened.

(Flocculant)
The liquid composition in the present invention contains a flocculant. Each of these components will be described in detail.
This aggregating agent has an action of aggregating, thickening or insolubilizing by reacting with or interacting with ink constituents.
Specifically, as the aggregating agent, at the time of mixing with the ink, at least a substance having an action of increasing the particle diameter of the coloring material (pigment) or the coloring material (pigment) component of the ink-jet ink is separated from the solvent. Examples include substances having an action. Examples of the flocculant include inorganic electrolytes, organic acids, and organic amine compounds.

  Inorganic electrolytes include alkali metal ions such as lithium ion, sodium ion, potassium ion, aluminum ion, barium ion, calcium ion, copper ion, iron ion, magnesium ion, manganese ion, nickel ion, tin ion, titanium ion, zinc Polyvalent metal ions such as ions, hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, and acetic acid, succinic acid, lactic acid, fumaric acid, fumaric acid, citric acid, salicylic acid, benzoic acid And the like, and organic carboxylic acids such as salts of organic sulfonic acids.

  Specific examples include lithium chloride, sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide, sodium sulfate, potassium nitrate, sodium acetate, potassium oxalate, sodium citrate, potassium benzoate and the like. Alkali metal salts and aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, sodium aluminum sulfate, potassium aluminum sulfate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium oxide, barium nitrate, thiocyanate Barium acid, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium benzoate, calcium acetate, salicylic acid Lucium, calcium tartrate, calcium lactate, calcium fumarate, calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, oxalic acid Iron, iron lactate, iron fumarate, iron citrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium lactate, manganese chloride, manganese sulfate, manganese nitrate, manganese dihydrogen phosphate , Manganese acetate, manganese salicylate, manganese benzoate, manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, thiocyanate Examples thereof include salts of polyvalent metals such as zinc acid and zinc acetate.

  Specific examples of organic acids include arginic acid, citric acid, glycine, glutamic acid, succinic acid, tartaric acid, cysteine, oxalic acid, fumaric acid, phthalic acid, maleic acid, malonic acid, lysine, malic acid, and formula ( Examples thereof include compounds represented by 1) and derivatives of these compounds.

Here, in the formula, X represents O, CO, NH, NR ₁ , S, or SO ₂ . R ₁ represents an alkyl group, and R ₁ is preferably CH ₂ , C ₂ H ₅ , or C ₂ H ₄ OH. R represents an alkyl group, and R is preferably CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OH. R may be contained in the formula or may not be contained. X is preferably CO, NH, NR, or O, and more preferably CO, NH, or O. M represents a hydrogen atom, an alkali metal or an amine. M is preferably H, Li, Na, K, monoethanolamine, diethanolamine, triethanolamine, etc., more preferably H, Na, K, and still more preferably a hydrogen atom. n is an integer of 3-7. n is preferably a case where the heterocyclic ring is a 6-membered ring or a 5-membered ring, more preferably a 5-membered ring. m is 1 or 2. As long as the compound represented by Formula (1) is a heterocyclic ring, it may be a saturated ring or an unsaturated ring. l is an integer of 1-5.

  As the compound represented by the formula (1), specifically, a compound having a furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, quinoline structure and further having a carboxyl group as a functional group Is mentioned. Specifically, 2-pyrrolidone-5-carboxylic acid, 4-methyl-4-pentanolide-3-carboxylic acid, furan carboxylic acid, 2-benzofuran carboxylic acid, 5-methyl-2-furan carboxylic acid, 2,5 -Dimethyl-3-furancarboxylic acid, 2,5-furandicarboxylic acid, 4-butanolide-3-carboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, 2-pyrone-6-carboxylic acid, 4-pyrone-2-carboxylic acid, 5-hydroxy-4-pyrone-5-carboxylic acid, 4-pyrone-2,6-dicarboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, thiophenecarboxylic Acid, 2-pyrrolecarboxylic acid, 2,3-dimethylpyrrole-4-carboxylic acid, 2,4,5-trimethylpyrrole-3-propionic acid, 3-hydroxy-2-yne Carboxylic acid, 2,5-dioxo-4-methyl-3-pyrroline-3-propionic acid, 2-pyrrolidinecarboxylic acid, 4-hydroxyproline, 1-methylpyrrolidine-2-carboxylic acid, 5-carboxy-1-methyl Pyrrolidine-2-acetic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, pyridinedicarboxylic acid, pyridinetricarboxylic acid, pyridinepentacarboxylic acid, 1,2,5,6-tetrahydro-1-methyl Examples include nicotinic acid, 2-quinolinecarboxylic acid, 4-quinolinecarboxylic acid, 2-phenyl-4-quinolinecarboxylic acid, 4-hydroxy-2-quinolinecarboxylic acid, and 6-methoxy-4-quinolinecarboxylic acid. .

  The organic acid is preferably citric acid, glycine, glutamic acid, succinic acid, tartaric acid, phthalic acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, Nicotinic acid, derivatives of these compounds, or salts thereof. More preferred are pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof. More preferred are pyrrolidone carboxylic acid, pyrone carboxylic acid, furan carboxylic acid, coumaric acid, or a compound derivative thereof, or a salt thereof.

The organic amine compound may be any of primary, secondary, tertiary and quaternary amines and salts thereof. Specific examples include tetraalkylammonium, alkylamine, benzalkonium, alkylpyridium, imidazolium, polyamine, and derivatives or salts thereof. Specifically, amylamine, butylamine, propanolamine, propylamine, ethanolamine, ethylethanolamine, 2-ethylhexylamine, ethylmethylamine, ethylbenzylamine, ethylenediamine, octylamine, oleylamine, cyclooctylamine, cyclobutylamine, cyclohexane Propylamine, cyclohexylamine, diisopropanolamine, diethanolamine, diethylamine, di-2-ethylhexylamine, diethylenetriamine, diphenylamine, dibutylamine, dipropylamine, dihexylamine, dipentylamine, 3- (dimethylamino) propylamine, dimethylethylamine, dimethyl Ethylenediamine, dimethyloctylamine, 1,3-dimethylbutylamine, dimethyl 1,3-propanediamine, dimethylhexylamine, amino-butanol, amino-propanol, amino-propanediol, N-acetylaminoethanol, 2- (2-aminoethylamino) -ethanol, 2-amino-2- Ethyl-1,3-propanediol, 2- (2-aminoethoxy) ethanol, 2- (3,4-dimethoxyphenyl) ethylamine, cetylamine, triisopropanolamine, triisopentylamine, triethanolamine, trioctylamine, Tritylamine, bis (2-aminoethyl) 1,3-propanediamine, bis (3-aminopropyl) ethylenediamine, bis (3-aminopropyl) 1,3-propanediamine, bis (3-aminopropyl) methylamine, Bis (2-ethylhexyl ) Amine, bis (trimethylsilyl) amine, butylamine, butylisopropylamine, propanediamine, propyldiamine, hexylamine, pentylamine, 2-methyl-cyclohexylamine, methyl-propylamine, methylbenzylamine, monoethanolamine, laurylamine, Nonylamine, trimethylamine, triethylamine, dimethylpropylamine, propylenediamine, hexamethylesidiamine, tetraethylenepentamine, diethylethanolamine, tetramethylammonium chloride, tetraethylammonium bromide, dihydroxyethyl stearylamine, 2-heptadecenyl-hydroxyethylimidazoline, lauryl Dimethylbenzylammonium chloride, cetylpyridinium mouth Ride, stearamide methylbiridium chloride, diallyldimethylammonium chloride polymer, diallylamine polymer, monoallylamine polymer, and the like.
More preferably, triethanolamine, triisopropanolamine, 2-amino-2-ethyl-1,3-propanediol, ethanolamine, propanediamine, propylamine and the like are used.

  The above flocculant compounds may be used alone or in combination of two or more. The content of the flocculant is 0.01 to 15% by mass, preferably 0.1 to 10% by mass. It is preferably 0.01% by mass or more and 30% by mass or less with respect to the total amount of the liquid. More preferably, they are 0.1 mass% or more and 15 mass% or less, More preferably, they are 1 mass% or more and 15 mass% or less. When the addition amount of the flocculant in the treatment liquid is less than 0.01% by mass, there is a case where the aggregation of the coloring material becomes insufficient at the time of ink contact, and the optical density, bleeding, and intercolor bleeding deteriorate. On the other hand, when the addition amount exceeds 30% by mass, the jetting characteristics deteriorated, and there was a case where the treatment liquid was not jetted normally.

The mass ratio of the flocculant and the surfactant described below is preferably 1: 100 to 1: 0.1, and more preferably 1:10 to 1: 0.5.
If the surfactant is more than 100 with respect to the flocculant 1, the optical density may be decreased, and if it is less than 0.1, sufficient drying may not be maintained.

(Surfactant)
The liquid composition for inkjet contains a surfactant.
As the surfactant in the present invention, a compound having a structure having both a hydrophilic part and a hydrophobic part in the molecule can be used effectively. Anionic surfactants, cationic surfactants, amphoteric surfactants can be used. Any of the nonionic surfactants can be used. Furthermore, the above-mentioned polymer substance (polymer dispersing agent) can also be used as a surfactant.

  Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfuric acid of higher alcohol ether. Ester salts and sulfonates, higher alkyl sulfosuccinates, higher alkyl phosphate esters, phosphate esters of higher alcohol ethylene oxide adducts, etc. can be used. Specific examples include dodecylbenzene sulfonate, Benzene sulfonate, isopropyl naphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, monobutylbiphenyl sulfonate, dibutylphenylphenol disulfonate, etc. They are used to.

  Nonionic surfactants include, for example, polypropylene glycol ethylene oxide adduct, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, Examples include sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, aliphatic alkanolamide, glycerin ester, sorbitan ester and the like.

Examples of the cationic surfactant include tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridium salts, imidazolium salts, and the like. Specific examples thereof include dihydroxyethyl stearylamine and 2-heptadecenyl. -Hydroxyethyl imidazoline, lauryl dimethyl benzyl ammonium chloride, cetyl pyridinium chloride, stearamide methyl pyridium chloride and the like.
In addition, biosurfactants such as spicrispolic acid, rhamnolipid, and lysolecithin can also be used.

  The amount of the surfactant to be added to the inkjet liquid composition in the present invention is not particularly limited, but is preferably 1% by mass or more, more preferably 1 to 10% by mass, and still more preferably 1%. Used in the range of ˜3 mass%. When the addition amount is less than 1% by mass, sufficient drying may not be maintained. When the addition amount exceeds 10% by mass, the optical density and the storage stability of the pigment ink may be deteriorated.

(water)
Water is added to the ink-jet liquid composition within the range of surface tension and viscosity.
The amount of water added is not particularly limited, but is preferably 75% by mass or less, more preferably 30% by mass or more and 75% by mass or less, with respect to the total mass of the ink-jet liquid composition. More preferably, they are 30 to 70 mass%, More preferably, they are 40 to 65 mass%, More preferably, they are 50 to 60 mass%. When the amount of water added is less than 30% by mass, the surfactant is likely to precipitate, and when it exceeds 75% by mass, the viscosity change due to evaporation may increase.

(Color material)
The liquid composition can contain a coloring material as desired. As the color material to be contained in the liquid composition, the same color materials as those described as the ink color material can be used. Preferably, a dye, a pigment having a sulfonic acid or a sulfonate on the surface, an anionic self-dispersing pigment, or a cationic self-dispersing pigment is used. These coloring materials are considered to be suitable because they hardly aggregate in the acidic region and have the effect of improving the storage stability of the liquid composition.

(Preferred physical properties of liquid composition)
The pH of the liquid composition is preferably 2.5 or more and 7.0 or less, more preferably 2.8 or more and 6.0 or less, and still more preferably 3.0 or more and 4.5 or less. When the pH of the ink-jet liquid composition is less than 2.5, aggregation may become strong, and dots may close and the optical density may decrease. On the other hand, when it is larger than 7.0, aggregation is reduced and the optical density may be lowered.

  The surface tension of the liquid composition is not particularly limited, but is preferably 20 mN / m or more and 40 mN / m or less. More preferably, it is 20 mN or more and 39 mN / m or less, More preferably, it is 20 mN / m or more and 35 mN / m or less. If the surface tension is less than 20 mN / m, the liquid may overflow on the nozzle surface and printing may not be performed normally. On the other hand, if it exceeds 40 mN / m, the permeability is slow and the drying time may be slow.

[Inkjet ink]
Next, the ink-jet ink will be described. The ink-jet ink contains at least a coloring material, a water-soluble solvent, and water.

(Color material)
The color material used in the present invention is not particularly limited as long as it has a function of forming an image by coloring, but contains at least one selected from dyes, pigments, and colored fine particles. It is preferable. Moreover, an ionic liquid can be contained as needed.

As the dye used in the present invention, either a water-soluble dye or a disperse dye may be used.
Specific examples of water-soluble dyes include C.I. I. Direct Black-2, -4, -9, -11, -17, -19, -22, -32, -80, -151, -154, -168, -171, -194, -195, C.I. I. Direct Blue-1, -2, -6, -8, -22, -34, -70, -71, -76, -78, -86, -112, -142, -165, -199, -200, -201, -202, -203, -207, -218, -236, -287, -307, C.I. I. Direct Red-1, -2, -4, -8, -9, -11, -13, -15, -20, -28, 31, -33, -37, -39, -51, -59, -62, -63, -73, -75, -80, -81, -83, -87, -90, -94, -95, -99, -101, -110, -189, -227, C.I. I. Direct Yellow-1, −2, −4, −8, −11, −12, −26, −27, −28, −33, −34, −41, −44, −48, −58, −86, -87, -88, -132, -135, -142, -144, -173, C.I. I. Food Black-1, -2, C.I. I. Acid Black-1, -2, -7, -16, -24, -26, -28, 31-1, -48, -52, -63, -107, -112, -118, -119, -121, -156, -172, -194, -208, C.I. I. Acid Blue-1, −7, −9, −15, −22, −23, −27, −29, −40, −43, −55, −59, −62, −78, −80, −81, -83, -90, -102, -104, -111, -185, -249, -254, C.I. I. Acid Red-1, -4, -8, -13, -14, -15, -18, -21, -26, -35, -37, -52, -110, -144, -180, -249, -257, -289, C.I. I. Acid Yellow-1, −3, −4, −7, −11, −12, −13, −14, −18, −19, −23, −25, −34, −38, −41, −42 -44, -53, -55, -61, -71, -76, -78, -79, -122, and the like.

  Next, specific examples of disperse dyes include C.I. I. Disperse Yellow-3, -5, -7, -8, -42, -54, -64, -79, -82, -83, -93, -100, -119, -122, -126, -160, -184: 1, -186, -198, -204, -224, C.I. I. Disperse Orange-13, -29, -31: 1, -33, -49, -54, -66, -73, -119, -163, C.I. I. Disperse Red-1, -4, -11, -17, -19, -54, -60, -72, -73, -86, -92, -93, -126, -127, -135, -145, -154, -164, -167: 1, -177, -181, -207, -239, -240, -258, -278, -283, -311, -343, -348, -356, -362, C. I. Disperse Violet-33, C.I. I. Disperse Blue-14, -26, -56, -60, -73, -87, -128, -143, -154, -165, -165: 1, -176, -183, -185, -201,- 214, -224, -257, -287, -354, -365, -368, C.I. I. Disperse Green-6: 1, -9 etc. are mentioned.

  As the pigment, any of organic pigments and inorganic pigments can be used. Examples of black pigments include carbon black pigments such as furnace black, lamp black, acetylene black, and channel black. In addition to the three primary color pigments of black, cyan, magenta, and yellow, specific color pigments such as red, green, blue, brown, and white, and metallic luster pigments such as gold and silver can also be used. Furthermore, a pigment newly synthesized for the present invention may be used.

  Specific examples of the pigment in the present invention include Raven7000, Raven5750, Raven5250, Raven5000 ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1190, Raven1190, Raven10, Raven10, Raven10, Raven1170 Regal 400R, Regal 330R, Regal 660R, Mogul L, Black Pearls L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monar h 1400 (above manufactured by Cabot Corporation), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black S150, Color Black S160, Color Black S160, Color Black P160, Color Black FW2P, Color Black FW2 , Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa), No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned, but are not limited thereto.

  For cyan, C.I. I. Pigment Blue-1, -2, -3, -15, -15: 1, -15: 2, -15: 3, -15: 4, -16, -22, -60, and the like. It is not limited.

  The magenta color is C.I. I. Pigment Red-5, -7, -12, -48, -48: 1, -57, -112, -122, -123, -146, -168, -184, -202, C.I. I. Pigment Violet-19 and the like, but are not limited thereto.

  Yellow is C.I. I. Pigment Yellow-1, -2, -3, -12, -13, -14, -16, -17, -73, -74, -75, -83, -93, -95, -97, -98, -114, -128, -129, -138, -151, -154, -155, -180, and the like, but are not limited thereto.

  In the present invention, it is also possible to use a pigment that is self-dispersible in water. The pigment that can be self-dispersed in water refers to a pigment that has many water-solubilizing groups on the pigment surface and can be stably dispersed in water without the presence of a polymer dispersant. Specifically, it can be self-dispersed in water by subjecting ordinary so-called pigments to surface modification treatments such as acid / base treatment, coupling agent treatment, polymer graft treatment, plasma treatment, oxidation / reduction treatment, etc. Pigments are obtained.

  Examples of the pigment that can be self-dispersed in water include a pigment obtained by subjecting the above pigment to surface modification treatment, as well as Cab-o-jet-200, Cab-o-jet-250, Cab- Commercially available self-dispersing products such as o-jet-260, Cab-o-jet-270, Cab-o-jet-300, IJX-444, IJX-55, Microjet Black CW-1, CW-2 manufactured by Orient Chemical Co., Ltd. Pigments can also be used.

Furthermore, a pigment coated with a resin can be used as a color material. This is called a microcapsule pigment, and not only commercially available ichrocapsule pigments manufactured by Dainippon Ink and Chemicals, Inc. or Toyo Ink, but also microcapsule pigments produced for the present invention may be used. it can.
It is also possible to use so-called colored fine particles in which a resin colored with a dye or pigment is dispersed.

  When pigments or colored fine particles are used as the color material, they can be dispersed by appropriately adjusting the hydrophilic / hydrophobic balance, surface functional group type, and surface functional group amount on the surface of the pigment or colored fine particles. It becomes possible. When a pigment is used as the color material, the pigment is preferably a self-dispersed pigment, a pigment dispersed using a polymer dispersant, a microcapsule pigment, or the like.

  The color material used in the present invention is 0.1% by mass or more and 50% by mass or less, preferably 1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 20% by mass or less with respect to the total mass of the ink. used. When the amount of the color material in the ink is less than 0.1% by mass, there is a case where a sufficient optical density cannot be obtained, and when the amount of the color material is more than 50% by mass, the ink ejectability is high. There was a case that became unstable.

(Dispersant)
In the present invention, a dispersant may be used to disperse the color material. As the dispersant, nonionic compounds, anionic compounds, cationic compounds, amphoteric compounds and the like can be used.
Examples thereof include a copolymer of monomers having an α, β-ethylenically unsaturated group. Examples of monomers having an α, β-ethylenically unsaturated group include ethylene, propylene, butene, pentene, hexene, vinyl acetate, allyl acetate, acrylic acid, methacrylic acid, crotonic acid, crotonic acid ester, itaconic acid, itacone Acid monoester, maleic acid, maleic acid monoester, maleic acid diester, fumaric acid, fumaric acid monoester, vinyl sulfonic acid, styrene sulfonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bismethacryloxy Styrene derivatives such as ethyl phosphate, methacryloxyethyl phenyl acid phosphate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, styrene, α-methylstyrene, vinyltoluene , Vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate, phenyl acrylate, alkyl methacrylate, phenyl methacrylate, cycloalkyl methacrylate, alkyl crotonate, dialkyl itaconate, dialkyl maleate Examples thereof include esters, vinyl alcohol, and derivatives of the above compounds.

  A copolymer obtained by copolymerizing a single monomer or a plurality of monomers having the α, β-ethylenically unsaturated group is used as a polymer dispersant. Specifically, styrene-styrene sulfonic acid copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl naphthalene- Methacrylic acid copolymer, vinyl naphthalene-acrylic acid copolymer, acrylic acid alkyl ester-acrylic acid copolymer, methacrylic acid alkyl ester-methacrylic acid copolymer, styrene-acrylic acid alkyl ester-acrylic acid copolymer, Examples include styrene-methacrylic acid phenyl ester-methacrylic acid, styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer, polystyrene, polyester, and polyvinyl alcohol.

  In the present invention, the dispersant used for the ink is preferably a weight average molecular weight of 2,000 to 50,000. When the molecular weight of the dispersant is less than 2,000, the colorant may not be stably dispersed. On the other hand, when the molecular weight exceeds 50,000, the viscosity of the ink is increased and the discharge property is deteriorated. Existed. A more preferred weight average molecular weight is 3,500 to 20,000.

  In the present invention, the dispersant added to the ink is used in an amount ratio of 1% to 100% by mass ratio with respect to the colorant. When the added amount ratio exceeds 100%, the ink viscosity becomes high, and there are cases where the ink ejection characteristics become unstable. On the other hand, when the addition amount was less than 1%, there was a case where the dispersion stability of the coloring material was lowered. The added amount of the dispersant is more preferably 2.5% or more and 75% or less, and further preferably 5% or more and 50% or less.

  In the present invention, the volume average particle diameter of the color material in the ink is preferably 30 nm or more and 250 nm or less. The volume average particle diameter of the color material particles refers to the particle diameter of the color material itself, or the particle diameter to which the additive has adhered when an additive such as a dispersant is adhered to the color material. In the present invention, a Microtrac UPA particle size analyzer 9340 (manufactured by Leeds & Northrup) was used as a volume average particle diameter measuring apparatus. The measurement was performed according to a predetermined measurement method with 4 ml of ink placed in a measurement cell. As parameters to be input immediately, the ink viscosity was used as the viscosity, and the density of the coloring material was used as the density of the dispersed particles. A more preferable volume average particle diameter is 60 nm or more and 250 nm or less, and further preferably 150 nm or more and 230 nm or less. When the volume average particle diameter of the particles in the ink is less than 30 nm, the optical density may be low. On the other hand, when it exceeds 250 nm, the dispersion stability of the coloring material may not be ensured. .

(Water-soluble organic solvent)
The ink contains a water-soluble organic solvent similar to the liquid composition.
The water-soluble organic solvent is used in an amount of 1 to 60% by mass, preferably 5 to 40% by mass. When the amount of the water-soluble organic solvent is less than 1% by mass, a sufficient optical density may not be obtained. Conversely, when the amount is more than 60% by mass, the viscosity of the liquid increases and the liquid In some cases, the injection characteristics of the engine became unstable.

(Preferable physical properties of inkjet ink)
The surface tension of the inkjet ink at 25 ° C. is preferably 20 mN / m or more and 60 mN / m or less. More preferably, it is 20 mN or more and 45 mN / m or less, More preferably, it is 20 mN / m or more and 35 mN / m or less. If the surface tension is less than 20 mN / m, the liquid may overflow on the nozzle surface and printing may not be performed normally. On the other hand, if it exceeds 60 mN / m, the permeability may be slow and the drying time may be slow.

  The viscosity at 25 ° C. of the inkjet ink is preferably 1.2 mPa · s or more and 25.0 mPa · s or less, more preferably 1.5 mPa · s or more and less than 10.0 mPa · s, and further preferably 1.8 mPa · s. · It is s or more and less than 5.0 mPa · s. When the viscosity of the ink for inkjet was larger than 25.0 mPa · s, there was a case where the dischargeability was lowered. On the other hand, when it is smaller than 1.2 mPa · s, there is a case where the jetting property is deteriorated.

  When a pigment is used as the color material, the ζ potential of the ink is preferably −60 mV or more and −10 mV or less. More preferably, it is −60 mV or more, and further preferably −15 mV or less, −50 mV or more, and −20 mV or less. When the ζ potential was less than −60 mV, there was a case where the water resistance decreased. Further, when used in combination with the treatment liquid, there is a case where the cohesiveness of the pigment cannot be ensured and the image quality is not improved. On the other hand, when the ζ potential exceeds −10 mV, there are cases where the ink storage stability cannot be ensured.

Here, the ζ potential was measured by ESA (Electrokinetic Sonic Amplitude method) using ESA-8000 (manufactured by Matec Applied Science) as a measuring device, and the zeta potential was calculated using the following calculation formula.
Formula: ζ potential = [ESA × η × G (α) −1] / [ε × c × Δρ × V]
In the formula, ESA indicates a pressure per unit electric field, which is a value obtained by measurement. η is the viscosity of the solvent, G (α) −1 is the correction term due to inertial force, ε is the dielectric constant, c is the speed of sound in the solvent, Δρ is the density difference between the solvent and the particles, and V is the volume fraction of the particles. Show. In the present invention, the measurement was performed at a temperature of 22.0 ° C. according to a predetermined measurement method. Further, as parameters used when calculating the zeta potential, η is the viscosity of the ink, ε is the dielectric constant of water, c is the speed of sound in water, Δρ is the density difference between the pigment and water, and V is the volume fraction of the pigment. It was. The zeta potential of the ink can be adjusted as follows, for example. The zeta potential represents the amount of potential generated by the charge on the pigment surface, and is determined by the charge density on the pigment surface and the charge state in the ink. The charge density on the pigment surface is considered to be determined by the amount of functional groups on the pigment surface and the dissociation state of the pigment surface functional groups. The zeta potential tends to increase as the amount of functional groups on the pigment surface increases and as the pigment surface functional groups dissociate. As a specific method, the method differs depending on whether a pigment that can be self-dispersed in water is used or a pigment that is dispersed using a dispersant.

(water)
Water is added in a range that achieves the above surface tension and viscosity. The amount of water added is not particularly limited, but is preferably 10% by mass to 99% by mass and more preferably 30% by mass to 80% by mass with respect to the entire inkjet ink.

(Additive to ink and liquid composition)
In addition, for ink and liquid compositions, for the purpose of controlling properties such as improvement of ejection properties, polyethylene derivatives, polyamines, polyvinyl pyrrolidone, polyethylene glycol, ethyl cellulose, carboxymethyl cellulose and other cellulose derivatives, polysaccharides and derivatives thereof, and other water-soluble compositions Polymers, acrylic polymer emulsions, polyurethane emulsions, polymer emulsions such as hydrophilic latex, hydrophilic polymer gels, cyclodextrins, macrocyclic amines, dendrimers, crown ethers, urea and its derivatives, acetamide, silicone surfactants An agent, a fluorosurfactant and the like can be added.
In order to adjust conductivity and pH, compounds of alkali metals such as potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide, triethanolamine, diethanolamine, ethanolamine, 2-amino-2-methyl Nitrogen-containing compounds such as -1-propanol, alkaline earth metal compounds such as calcium hydroxide, acids such as sulfuric acid, hydrochloric acid and nitric acid, strong acid and weak alkali salts such as ammonium sulfate, and the like can be added.
In addition, a pH buffer, an antioxidant, a fungicide, a viscosity modifier, a conductive agent, an ultraviolet absorber, and the like can be added as necessary.

(Inkjet ink tank)
The ink-jet ink tank of the present invention accommodates each liquid (ink-jet ink or ink-jet liquid composition in the present invention) of the ink-jet ink set of the present invention. For example, JP-A-2001-138541 The described ink tanks can be applied. In this case, even when ink is filled in the ink tank and ink is ejected from the recording head, the change in ink characteristics during long-term storage in the ink tank is suppressed, and in particular, the ejection properties from the recording head during long-term storage are sufficiently satisfactory. It will be a thing.

(Inkjet recording method, inkjet recording apparatus)
The ink jet recording method of the present invention is a method of forming an image by applying and discharging each liquid (ink jet ink, ink jet liquid composition) to a recording medium using an ink set for ink jet. Printing is performed so that the ink for ink jet and the liquid composition for ink jet are brought into contact with each other.

  On the other hand, an ink jet recording apparatus of the present invention includes a recording head that uses an ink set for ink jet and discharges each liquid onto a recording medium. These are not only ordinary inkjet recording apparatuses, but also recording apparatuses equipped with heaters for controlling the drying of ink, or intermediate transfer mechanisms, and after printing a recording material on the intermediate, A recording apparatus or the like that transfers to a recording medium can be applied.

  In the ink jet recording method (apparatus) of the present invention, the liquid volume per drop is preferably 1 pL or more and 200 pL or less. More preferably, it is 1 pL or more and 100 pL or less, More preferably, it is 1 pL or more and 80 pL or less. When the liquid mass per drop exceeded 200 pL, the resolution sometimes deteriorated. This is because the contact angle of the ink and the liquid composition with respect to the recording medium changes depending on the drop amount, and the drop tends to spread in the paper surface direction as the drop amount increases. When the liquid mass per drop was less than 0.01 ng, there was a case where the jetting stability deteriorated.

  However, in an ink jet apparatus capable of ejecting a plurality of drops from a single nozzle, the drop amount refers to the minimum drop amount that can be printed.

  In addition, when an inkjet ink set is used, the inkjet ink and the inkjet liquid composition are applied on the recording medium so as to be in contact with each other, but the inkjet ink and the inkjet liquid composition are in contact with each other. This is because the ink is agglomerated by the action of the aggregating component, and the recording method is excellent in color developability, solid portion unevenness, optical density, bleeding, intercolor bleeding, and drying time. As long as they are in contact with each other, they may be given so as to be adjacent to each other or may be given so as to cover them.

  The order of application to the recording medium is to apply the inkjet ink after applying the inkjet liquid composition. This is because the components of the inkjet ink can be effectively aggregated by applying the inkjet liquid composition first. The ink jet ink may be applied at any time after the ink jet liquid composition is applied. Preferably, it is 0.5 second or less after the application of the inkjet liquid composition.

  In the ink jet recording method (apparatus) of the present invention, the mass ratio between the ink application amount for ink jet and the liquid composition application amount required for forming one pixel is preferably 1:20 to 20: 1. . More preferably, it is 1: 10-10: 1, More preferably, it is 1: 5-5: 1. When the amount of ink applied for inkjet is too small or too large relative to the amount of applied liquid composition for inkjet, aggregation is insufficient, resulting in a decrease in optical density, deterioration of bleeding, and deterioration of bleeding between colors. Existed. Here, the pixel is a grid point formed when a desired image is divided by the minimum distance that can be applied with ink in the main scanning direction and the sub-scanning direction, and is appropriate for each pixel. By applying an appropriate ink set, the color and image density are adjusted, and an image is formed.

  In particular, the amount of inkjet liquid composition applied to the amount of inkjet ink applied to form one pixel is preferably 60% by volume or less, more preferably 5 to 50% by volume, and further Preferably it is 10-30 volume%.

  The ink jet recording method (apparatus) of the present invention preferably adopts a thermal ink jet recording method or a piezo ink jet recording method from the viewpoint of the effect of improving bleeding and intercolor bleeding. The cause of this is not clear, but in the case of the thermal ink jet recording method, the ink is heated at the time of ejection and has a low viscosity, but since the temperature of the ink is lowered on the recording medium, the viscosity rapidly increases. Become. For this reason, it is considered that bleeding and intercolor bleeding have an improving effect. On the other hand, in the case of the piezo ink jet method, it is possible to discharge a high-viscosity liquid, and the high-viscosity liquid can suppress spreading in the paper surface direction on the recording medium. It is estimated that there is an improvement effect on intercolor bleeding.

  In the ink jet recording method (apparatus) of the present invention, replenishment (supply) of the ink and the liquid composition to the recording head is performed from an ink tank (including the liquid composition tank) filled with each liquid of the ink and the liquid composition. It should be done. The ink tank is preferably a cartridge system that can be attached to and detached from the apparatus, and the ink and liquid composition can be easily replenished by replacing the ink tank of this cartridge system.

  Hereinafter, preferred embodiments of the ink jet recording apparatus of the present invention will be described in detail with reference to the drawings. In the drawings, members having substantially the same functions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing an external configuration of a preferred embodiment of an ink jet recording apparatus of the present invention. FIG. 2 is a perspective view showing an internal basic configuration of the ink jet recording apparatus (hereinafter referred to as an image forming apparatus) of FIG.

  The image forming apparatus 100 of this embodiment has a configuration that operates based on the above-described inkjet recording method of the present invention to form an image. That is, as shown in FIGS. 1 and 2, an image forming apparatus 100 mainly includes an external cover 6, a tray 7 on which a predetermined amount of recording medium 1 such as plain paper can be placed, and the recording medium 1 as an image forming apparatus. A conveyance roller (conveying means) 2 for conveying the sheet 100 one by one; an image forming section 8 (image forming means) for forming an image by discharging ink and a liquid composition onto the surface of the recording medium 1; The main ink tank 4 supplies ink and liquid composition to each sub ink tank 5 of the image forming unit 8.

  The conveyance roller 2 is a paper feed mechanism constituted by a pair of rollers rotatably disposed in the image forming apparatus 100, sandwiches the recording medium 1 set on the tray 7, and has a predetermined amount of recording medium 1. Are conveyed one by one into the image forming apparatus 100 at a predetermined timing.

  The image forming unit 8 forms an image with ink on the surface of the recording medium 1. The image forming unit 8 mainly includes a recording head 3, a sub ink tank 5, a power supply signal cable 9, a carriage 10, a guide rod 11, a timing belt 12, a driving pulley 13, and a maintenance unit 14. ing.

  The sub ink tank 5 includes sub ink tanks 51, 52, 53, 54, and 55 in which different color inks and liquid compositions are stored so as to be ejected from the recording head. These include, for example, black ink (K), yellow ink (Y), magenta ink (M), and cyan ink (C) as ink-jet ink, and a liquid composition is supplied from the main ink tank 4 and stored. Yes.

  The sub ink tank 5 is provided with an exhaust hole 56 and a supply hole 57, respectively. When the recording head 3 moves to the standby position (or replenishment position), the exhaust pin 151 and the replenishment pin 152 of the replenishing device 15 are inserted into the exhaust hole 56 and the replenishment hole 57, respectively. 5 and the replenishing device 15 can be connected. The replenishing device 15 is connected to the main ink tank 4 via the replenishing pipe 16, and replenishes ink or liquid composition from the main ink tank 4 to the sub ink tank 5 through the replenishing hole 57.

  Here, the main ink tank 4 also has main ink tanks 41, 42, 43, 44, 45 in which inks of different colors and liquid compositions are stored. These include, for example, black ink (K), yellow ink (Y), magenta ink (M), and cyan ink (C) as ink-jet ink, and a liquid composition as ink-jet liquid composition. Are detachably stored in the image forming apparatus 100.

  Furthermore, the power supply signal cable 9 and the sub ink tank 5 are connected to the recording head 3, and when external image recording information is input from the power supply signal cable 9 to the recording head 3, the recording head 3 detects the image recording information. Based on the above, a predetermined amount of ink is sucked from each ink tank and discharged onto the surface of the recording medium. The power supply signal cable 9 also has a role of supplying power necessary for driving the recording head 3 to the recording head 3 in addition to the image recording information.

  The recording head 3 is arranged and held on a carriage 10, and the carriage 10 is connected to a guide rod 11 and a timing belt 12 connected to a driving pulley 13. With such a configuration, the recording head 3 extends along the guide rod 11 and is parallel to the surface of the recording medium 1 and perpendicular to the conveyance direction X (sub-scanning direction) of the recording medium 1 (main scanning direction). It can also be moved in the scanning direction.

  The image forming apparatus 100 includes control means (not shown) that adjusts the drive timing of the recording head 3 and the drive timing of the carriage 10 based on the image recording information. Thereby, an image based on the image recording information can be continuously formed in a predetermined region of the surface of the recording medium 1 that is transported at a predetermined speed along the transport direction X.

  The maintenance unit 14 is connected to a decompression device (not shown) via a tube. Further, the maintenance unit 14 is connected to the nozzle portion of the recording head 3 and has a function of sucking ink from the nozzles of the recording head 3 by reducing the pressure in the nozzles of the recording head 3. By providing the maintenance unit 14, if necessary, excess ink adhering to the nozzles during operation of the image forming apparatus 100 is removed, or evaporation of ink from the nozzles is suppressed when the operation is stopped. be able to.

  FIG. 3 is a perspective view showing an external configuration of another preferred embodiment of the ink jet recording apparatus of the present invention. FIG. 4 is a perspective view showing an internal basic configuration of the ink jet recording apparatus (hereinafter referred to as an image forming apparatus) of FIG. The image forming apparatus 101 of the present embodiment has a configuration that operates based on the above-described inkjet recording method of the present invention to form an image.

  In the image forming apparatus 101 shown in FIGS. 3 and 4, the width of the recording head 3 is the same as or larger than the width of the recording medium 1, does not have a carriage mechanism, and is in the sub-scanning direction (conveying direction of the recording medium 1: arrow X). Direction) paper feed mechanism (the transport roller 2 is shown in the present embodiment, but it may be a belt-type paper feed mechanism, for example).

  Although not shown, a group of nozzles that discharge each color (including the liquid composition) similarly to the case where the sub ink tanks 51 to 55 are sequentially arranged in the sub scanning direction (the conveyance direction of the recording medium 1: the arrow X direction). Are also arranged in the sub-scanning direction. Other configurations are the same as those of the image forming apparatus 100 shown in FIGS. In the drawing, since the recording head 3 does not move, the sub ink tank 5 is always connected to the replenishing device 15. However, the sub ink tank 5 may be connected to the replenishing device 15 at the time of ink replenishment.

  In the image forming apparatus 101 shown in FIGS. 3 and 4, since the printing in the width direction (main scanning direction) of the recording medium 1 is collectively performed by the recording head 3, the configuration of the apparatus is simpler than the system having the carriage mechanism. Yes, printing speed will be faster.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention.

[Preparation of ink and liquid composition]
In accordance with the following ink composition and liquid composition (treatment liquid) composition, the compounds were mixed, stirred, and then filtered using a membrane filter having an opening of 5 μm to obtain a desired ink and liquid composition.

<Ink A>
Cabojet-300 (manufactured by Cabot) (self-dispersing pigment / carboxylic acid group): 4% by mass
Styrene-acrylic acid copolymer (NaOH partial neutralization, acid value = 150, weight average molecular weight = 7500): 0.5% by mass
・ Diethylene glycol: 10% by mass
・ Glycerin: 5% by mass
・ 2-pyrrolidone: 5 mass ・ Acetylene glycol ethylene oxide adduct: 1 mass%
-Ion-exchanged water: balance The ζ potential of this ink was -21 mV, the volume average particle size was 106 nm, the viscosity was 3.3 mPa · s, and the surface tension was 31 mN / m.

<Ink B>
・ C. I. Pigment Blue 15: 3 (self-dispersing pigment / sulfonic acid group): 4% by mass
Styrene-lauric acid-methacrylic acid copolymer (NaOH partial neutralization, acid value = 240, weight average molecular weight = 4500): 0.5% by mass
・ Diethylene glycol: 20% by mass
・ Sulfolane: 5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
Ion-exchanged water: remainder The ζ potential of this ink was −28 mV, the volume average particle diameter was 98 nm, the viscosity was 3.0 mPa · s, and the surface tension was 30 mN / m.

<Processing liquid A>
Magnesium nitrate: 10.6% by mass
・ Diethylene glycol: 30% by mass
・ Butyl carbitol: 4% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 6.9, the electrical conductivity was 2.6 S / m, the surface tension was 31 mN / m, and the viscosity was 3.0 mPa · s.

<Processing liquid B>
Magnesium nitrate: 5.3% by mass
・ Diethylene glycol: 20% by mass
Propylene glycol: 2% by mass
・ Butyl carbitol: 10% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 7.2, the electrical conductivity was 1.4 S / m, the surface tension was 33 mN / m, and the viscosity was 3.3 mPa · s.

<Processing liquid C>
・ Calcium nitrate: 5.6% by mass
・ Diethylene glycol: 8% by mass
・ 2-Pyrrolidone: 3% by mass
・ 1,2-hexanediol: 10% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 7.3, the electrical conductivity was 1.2 S / m, the surface tension was 30 mN / m, and the viscosity was 3.3 mPa · s.

<Processing liquid D>
・ Polyallylamine: 2.5% by mass
・ Diethylene glycol: 15% by mass
・ Glycerin: 5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 7.1, the conductivity was 0.17 S / m, the surface tension was 31 mN / m, and the viscosity was 3.1 mPa · s.

<Processing liquid E>
-Polyallylamine hydrochloride: 3% by mass
Propylene glycol: 12% by mass
・ 1,2-pentanediol: 3.0% by mass
・ 1,2-butanediol: 1.0% by mass
-Acetylene glycol ethylene oxide addition: 1% by mass
-Ion-exchange water: remainder The pH of this liquid was 7.2, the conductivity was 0.20 S / m, the surface tension was 33 mN / m, and the viscosity was 3.2 mPa · s.

<Processing liquid F>
・ Succinic acid: 1.6% by mass
・ Sodium hydroxide: 0.9% by mass
・ Diethylene glycol: 13% by mass
Propylene glycol: 5% by mass
・ 1,4-Butanediol: 1.5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 4.5, the electrical conductivity was 0.10 S / m, the surface tension was 33 mN / m, and the viscosity was 3.1 mPa · s.

<Processing liquid G>
・ Succinic acid: 1.6% by mass
・ Ammonia: 0.5% by mass
・ Diethylene glycol: 13% by mass
Propylene glycol: 5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 4.5, the electrical conductivity was 0.100 S / m, the surface tension was 31 mN / m, and the viscosity was 3.1 mPa.s.

<Treatment liquid H>
・ 2-Pyrrolidonecarboxylic: 8% by mass
・ Lithium hydroxide: 1.8% by mass
・ Glycerin: 10% by mass
・ 1,2-hexanediol: 4.5% by mass
-Acetylene glycol ethylene oxide addition: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 6.4, the electrical conductivity was 0.63 S / m, and the viscosity was 3.0 mPa.s.

<Treatment liquid I>
2-pyrrolidonecarboxylic acid: 7% by mass
-Lithium hydroxide 1.9% by mass
・ Diethylene glycol: 15% by mass
・ 1,6-hexanediol: 2% by mass
-Acetylene glycol ethylene oxide addition: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 4.0, the surface tension was 31 mN / m, the conductivity was 0.60 S / m, and the viscosity was 3.0 mPa · s.

<Treatment liquid I>
-2-furancarboxylic acid: 7.3 mass%
Tetramethylammonium hydroxide: 16% by mass
・ Glycerin: 13% by mass
Propylene glycol: 5% by mass
-Acetylene glycol ethylene oxide addition: 1% by mass
-Ion exchange water: remainder The pH of this liquid was 4.0, the surface tension was 31 mN / m, the conductivity was 0.59 S / m, and the viscosity was 3.0 mPa · s.

The physical properties of the ink and the treatment liquid were as follows.
The conductivity was measured with MPC227 pH / Conductivity Meter manufactured by METTER TOLEND.

  The zeta potential was measured by ESA method (Electrokinetic Sonic Amplitude method) using ESA-8000 (manufactured by Matec Applied Science) as a measuring device, and the zeta potential was calculated using the following calculation formula.

(Examples 1-12, Comparative Examples 1-8)
In Examples 1-12 and Comparative Examples 1-8, it printed using the ink set of Table 2 using the processing liquid of Table 1, and evaluated the processing liquid and the ink set.

[Evaluation]
<Optical density>
Printing is performed by using a 800 pi, 256 nozzle prototype piezo print head (14 ng drop amount), ejecting a liquid composition onto FX-C ² paper (Fuji Xerox Co., Ltd.), and then ejecting ink from the liquid composition. went. At this time, printing was performed in a general environment (temperature 23 ± 0.5 ° C., humidity 55 ± 5% RH). Further, when the ink and the liquid composition are ejected, the mass ratio of the applied amount of the ink and the liquid composition for forming one pixel is set to 1: 0.2.
The optical density of the printed portion obtained above was measured using X-Rite 404 (manufactured by X-Rite). The results are shown in Table 2.
-Evaluation criteria (black ink)-
○: Optical density is 1.4 or more Δ: Optical density is more than 1.1 and less than 1.4 ×: Optical density is 1.1 or less -Evaluation criteria (color ink)-
○: Optical density is 1.2 or more Δ: Optical density is more than 0.9 and less than 1.2 ×: Optical density is 0.9 or less

《Bludge》
In the optical density evaluation, the printed print samples are left for 24 hours, and then a predetermined limit sample (a plurality of evaluators perform ordering from an image with good bleeding to a bad image created with an actual print pattern). , Which was numerically expressed as a rank), and sensory evaluation was performed on the degree of blur. The results are shown in Table 2.
-Evaluation criteria-
○: Smudge is very small. △: Smudge has occurred but is at an acceptable level. ×: Smudge has occurred significantly outside the allowable range.

<< Deposition of surfactant (SA) >>
The SA deposition state on the nozzle surface of the prototype piezo print head after the printing was visually observed, and the treatment liquid was evaluated according to the following evaluation criteria. The results are shown in Table 1.
-Evaluation criteria-
○: SA precipitation is very small Δ: SA precipitation is at an acceptable level ×: SA precipitation is significantly outside the allowable range

<Nozzle reliability evaluation>
The nozzle reliability was judged based on the change over time in the ink ejection speed. That is, the ink ejection speed is measured in the initial state. Thereafter, after 1 × 10 ⁸ pulse printing, the ink ejection speed was measured. The ratio of the ink ejection speed after 1 × 10 ⁸ pulse printing to the ink ejection speed in the initial state was calculated and evaluated according to the following evaluation criteria. The evaluation criteria are as follows.
-Evaluation criteria-
○: 1 × 10 ⁸ pulse injection speed is 90% or more of initial injection speed Δ: 1 × 10 ⁸ pulse injection speed is 75% or more and less than 90% of initial injection speed ×: 1 × 10 ⁸ pulse injection speed <75% of initial injection speed

尚、表中の水溶性溶媒の表面張力は５％水溶液における数値である。

The surface tension of the water-soluble solvent in the table is a numerical value in a 5% aqueous solution.

  As is apparent from Tables 1 and 2, the product (a × b) of the treatment liquid with conductivity a and viscosity b is less than 0.4, or the surface tension of a 5% aqueous solution is 52 mN / m. In the treatment liquids that do not use the following water-soluble solvent, it is not possible to prevent the precipitation of the surfactant on the nozzle surface, and not only the nozzle reliability is inferior, but also the image quality obtained using it is It was inferior in terms of optical density. On the other hand, in a treatment liquid containing a water-soluble solvent having a surface tension of 52 mN / m or less with a 5% aqueous solution of 0.4 or more, precipitation of the surfactant can be prevented, nozzle reliability is good, and optical A high-quality image was obtained in terms of density.

1 is a perspective view showing an external configuration of a preferred embodiment of an ink jet recording apparatus of the present invention. FIG. 2 is a perspective view showing an internal basic configuration of the ink jet recording apparatus of FIG. 1. It is a perspective view which shows the external appearance structure of another suitable one Embodiment of the inkjet recording device of this invention. FIG. 4 is a perspective view showing an internal basic configuration of the ink jet recording apparatus of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100, 101 Image forming apparatus 1 Recording medium 2 Conveying roller 3 Recording head 4 Main ink tank 5 Sub ink tank 6 External cover 7 Tray 8 Image forming part 9 Power supply signal cable 10 Carriage 11 Guide rod 12 Timing belt 13 Drive pulley 14 Maintenance unit 15 Replenisher

Claims (14)

A liquid composition containing at least a flocculant, a water-soluble solvent, a surfactant, and water, wherein the value of a × b is 0.4 or more when the conductivity is aS / m and the viscosity is bmPa · s. A liquid composition for inkjet, comprising one or more types having a surface tension of 52 mN / m or less of a 5% aqueous solution of the water-soluble solvent. The ink-jet liquid according to claim 1, wherein the water-soluble solvent having a surface tension of 52 mN / m or less is at least one selected from the following general formula (1) and the following general formula (2). Composition.
Formula _{(1) C n H (2n} + 2-m) - (OH) m
Formula _{(2) C p H (2p} + 1) - (C q H 2q O q) r -OH
(In general formula (1), n represents 4-8, m represents 2-3. In general formula (2), p represents 1-6, q represents 2-4, r is 1 Represents 4) The liquid composition for inkjet according to claim 1 or 2, wherein the addition amount of the surfactant is 1.0% by mass or more. The liquid composition for inkjet according to any one of claims 1 to 3, wherein an addition amount of the water-soluble solvent having a surface tension of 52 mN / m or less is 3.0% by mass or more. The liquid composition for inkjet according to any one of claims 1 to 4, further comprising a water-soluble solvent having a surface tension of more than 52 mN / m. The liquid composition for ink jet according to claim 5, wherein the total amount of the water-soluble solvent having a surface tension of 52 mN / m or less and more than 52 mN / m is 10% by mass or more. The liquid composition for inkjet according to any one of claims 1 to 6, wherein a mass ratio of the flocculant and the surfactant when mixed is 1: 100 to 1: 0.1. The liquid composition for inkjet according to any one of claims 1 to 7, wherein the amount of water added is 75 mass% or less. The liquid composition for inkjet according to any one of claims 1 to 8, wherein the surface tension is 25 to 40 mN / m. An inkjet ink set comprising an inkjet ink and an inkjet liquid composition containing a colorant, a water-soluble solvent, a surfactant and water, wherein the inkjet liquid composition is any one of claims 1 to 9. An ink-jet ink set, which is the ink-jet liquid composition described in the item. The ink-jet ink set according to claim 10, wherein the water-soluble solvent and the surfactant contained in the ink-jet ink are the same as the water-soluble solvent and the surfactant contained in the ink-jet liquid composition. . An ink-jet ink tank containing the ink-jet ink and the ink-jet liquid composition of the ink-jet ink set according to claim 10. An inkjet recording method using an inkjet ink set, wherein the inkjet ink set is the inkjet ink set according to claim 10 or 11, wherein the inkjet ink and the inkjet liquid composition are in contact with each other. An ink jet recording method comprising forming an image on a recording medium as described above. An inkjet recording apparatus comprising a recording head for ejecting each liquid in an inkjet ink set onto a recording medium, wherein the inkjet ink set is the inkjet ink set according to claim 10 or 11. An ink jet recording apparatus.

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