JP2007216584A - Inkjet ink set, inkjet ink tank, inkjet recording method and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet ink set, an inkjet ink tank, an inkjet recording method and an inkjet recording device excellent in fixture. <P>SOLUTION: By employing ink including an anionic or cationic dye and a hydrophilic polymer homopolar with the dye or non-ionic and a processing liquid including a flocculating agent selected from the group consisting of a polyvalent metal salt, an organic amine, an onium salt, an organic acid or its salt and inorganic acids as an ink set, the fixing of ink is accelerated by bringing the ink into contact with the processing liquid on a recording medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet ink set, an ink jet ink tank, an ink jet recording method, and an ink jet 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 this ink jet system, there is a method of preventing bleeding and improving image quality by discharging a treatment liquid having an action of aggregating or insolubilizing a coloring material as an ink component so as to contact the ink on the recording medium. It is being considered.

In this method, for example, an ink containing an anionic dye and / or an anionic compound and a pigment as a coloring material is prepared by adding a high molecular weight water-soluble nitrogen-containing cationic compound and a low molecular weight cationic surfactant to the treatment liquid. In addition, a method of coagulating or insolubilizing is disclosed (for example, see Patent Document 1).
Further, a method is disclosed in which at least two kinds of cationic substances having different molecular weights are contained in the treatment liquid, and agglomerated or insolubilized with an ink containing an anionic dye as a coloring material (see, for example, Patent Document 2). .

However, when the ink components are aggregated or insolubilized as in these methods, the color material is present in the vicinity of the surface of the recording medium at a high density. This causes a problem that the fixing property is deteriorated due to the presence of the above. In any of the above methods, the fixability is not sufficient, and the actual situation is that improvement is desired.
JP-A-8-20159 JP-A-8-20720

  An object of the present invention is to provide an ink set having excellent fixing properties in view of various problems in the past. Another object of the present invention is to provide an ink tank containing the ink set. Furthermore, an object of the present invention is to provide a 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> having at least an anionic or cationic water-soluble dye, an ink containing at least one hydrophilic polymer having the same polarity or a nonionic property as the dye, and a treatment liquid containing at least an aggregating agent. Ink set for inkjet.
<2> The inkjet ink set according to <1>, wherein the flocculant is at least one selected from polyvalent metal salts, organic amines, onium salts, organic acids, and inorganic acids.

<3> The inkjet ink set according to <1> or <2>, wherein the amount of the hydrophilic polymer is 0.1 to 5% by mass.
<4> The ink set for inkjet according to any one of <1> to <3>, wherein the amount of the hydrophilic polymer is 20% by mass or more based on the mass of the coloring material.

<5> An ink-jet ink tank comprising the ink-jet ink set according to any one of the above items <1> to <4>.
<6> A recording method comprising forming an image by applying the ink set according to any one of <1> to <4> onto a recording medium.

<7> An inkjet recording apparatus including a recording head for ejecting each liquid in an inkjet ink set onto a recording medium, wherein the inkjet ink set is any one of the above items <1> to <4>. An ink jet recording apparatus comprising the ink jet ink set according to claim 1.

  According to the present invention, it is possible to provide an ink set that is excellent in fixability and excellent in water resistance, gas resistance, ink ejection stability, and drying. In addition, according to the present invention, it is possible to provide an ink tank containing the ink set. Furthermore, according to the present invention, a recording method using the ink set can be provided. Moreover, according to the present invention, an ink jet recording apparatus using the ink set can be provided.

Hereinafter, the present invention will be described in detail.
[Inkjet ink set]
The inkjet ink set of the present invention includes an inkjet ink (hereinafter also referred to as “ink”) and an inkjet processing liquid (hereinafter also referred to as “processing liquid”).

<Ink>
The ink according to the present invention includes at least an anionic or cationic dye and at least one hydrophilic polymer having the same polarity or nonionic property as the dye.
Hereinafter, the ink (ink jet ink of the present invention) will be described.

(Anionic or cationic water-soluble dye)
The dye used in the ink of the present invention is not particularly limited as long as it is at least an anionic dye or a cationic water-soluble dye (also collectively referred to as “dye”). For example, a conventionally known compound or a newly synthesized compound having an appropriate color tone and density can be used.
Further, any one of these can be used in combination.

  Specific examples of the anionic dye include C.I. I. Direct black-2, -4, -9, -11, -17, -19, -22, -32, -80, -151, -154, -168, -171, -194, -195;

  C. 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. 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. Direct violet-2, -5, -9, -12, -18, -25, -37, -43, -66, -72, -76, -84, -92, -107;
C. I. Direct Yellow-1, -2, -4, -8, -11, -12, -26, -27, -28, 333, -34, -41, -44, -48, -58, -86, -87, -88, -132, -135, -142, -144, -173;

C. I. Food black-1, -2;
C. I. Acid Black-1, -2, -7, -16, -24, -26, -28, -31, -48, -52, -63, -107, -112, -118, -119, -121, -156, -172, -194, -208;
C. 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. Acid Red-1, -4, -8, -13, -14, -15, -18, -21, -26, -35, -37, -52, -110, -144. -180, -249, -257;
C. 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
Etc.
ILFORD Y-104, Y-1189, and the like.

  Specific examples of the cationic dye include C.I. I. Basic yellow-1, -11, -13, -19, -25, -33, -36; I. B. basic red-1, -2, -9, -12, -13, -38, -39, -92; I. Basic Blue-1, -3, -5, -9, -19, C.I. I. -24, -25, 26, 28 and the like.

  The content of the dye is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.1 to 20% by mass with respect to the total ink amount, from the viewpoint of clogging suppression at the nozzle tip and the density of the obtained image. It is 10 mass%, More preferably, it is 0.1-7 mass%.

(Hydrophilic polymer)
The hydrophilic polymer contained in the ink in the present invention needs to be a hydrophilic polymer having the same polarity as that of the dye contained in the ink or a nonionic polymer.
By making the hydrophilic polymer the same polarity or nonionic hydrophilic polymer as the dye, the liquid stability of the ink before coming into contact with the treatment liquid is maintained, and the ejection stability of the ink is improved. In addition, by using a hydrophilic polymer, it is possible to improve color reproducibility by bleeding between colors.

  As the hydrophilic polymer, either a linear polymer or a non-linear polymer can be used. In the case of aggregation or insolubilization of the polymer by the treatment liquid, the interaction due to the entanglement between the polymer molecular chains is increased, and excellent fixability can be expressed with the same amount as the linear polymer. Preferably there is.

The hydrophilic polymer may be at least one of an anionic polymer, a nonionic polymer, and a cationic polymer. Therefore, when an anionic dye is used as the dye, an anionic polymer or a nonionic polymer is preferable. On the other hand, when a cationic dye is used as the dye, it is preferable to use a cationic polymer or a nonionic polymer. .
In addition, the hydrophilic polymer may be a mixed polymer selected from an anionic polymer, a cationic polymer, and a nonionic polymer. The hydrophilic polymer may be obtained by adding a crosslinking agent to a single monomer or may be a copolymer of two or more different monomers. A hydrophilic polymer can be obtained by these monomer species, polymerization method, and crosslinking method.

Examples of the anionic polymer or the cationic polymer include a copolymer of monomers having an α, β-ethylenically unsaturated group.
Examples of monomers having an α, β-ethylenically unsaturated group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, Vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, allyl phosphonic acid, vinyl phosphonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bismethacryloxyethyl phosphate, methacryloxyethyl phenyl acid phosphate, ethylene glycol Dimethacrylate, diethylene glycol dimethacrylate, styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives Body, alkyl acrylate, phenyl acrylate, methacrylic acid alkyl esters, methacrylic acid phenyl ester, methacrylic acid cycloalkyl ester, crotonic acid alkyl ester, itaconic acid dialkyl esters, maleic acid dialkyl ester and the like.

  Specifically, as a copolymer obtained by copolymerizing a monomer having an α, β-ethylenically unsaturated group alone or plurally, polyacrylic acid, polymethacrylic acid, styrene-styrenesulfonic 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, acrylic acid-acrylonitrile copolymer, styrene-alkyl methacrylate-methacrylic acid copolymer, styrene-alkyl methacrylate-acrylic acid Copolymer, styrene-alkyl acrylate And a styrene-acrylic acid copolymer, a styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, and a styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer.

  Examples of nonionic polymers include polyvinyl alcohol, polyvinyl pororidone, starch, and methylcellulose.

  The weight average molecular weight of the hydrophilic polymer is preferably 1000 to 100,000, more preferably 1500 to 50000, and still more preferably 1500 to 30000. By setting the weight average molecular weight in the above range, it is possible to achieve both ink ejection characteristics and abrasion resistance.

  The acid value of the anionic polymer is preferably 80 to 250 mgKOH / g, more preferably 90 to 200 mgKOH / g. By setting the acid value within the above range, fixability can be obtained while improving solubility in ink. Here, the acid value refers to the number of milligrams of potassium hydroxide necessary to neutralize the acid contained in 1 g of the sample.

  The glass transition temperature (Tg) of the hydrophilic polymer is preferably 0 to 150 ° C, more preferably 20 to 100 ° C. By setting the glass transition temperature (Tg) within the above range, good fixability can be obtained. Here, the glass transition point refers to a value measured by a method (DSC method) defined in ASTM D3418-82.

  The combination of the hydrophilic polymer and the dye in the ink needs to contain at least an anionic or cationic dye and one or more hydrophilic polymers having the same polarity or nonionic as the dye. Among these, from the viewpoint of compatibility between the effect of improving fixability and the long-term storage stability of the ink, a combination of an anionic dye and an anionic polymer and / or a nonionic polymer is preferable. Among these, an anionic dye and an anionic polymer are preferred. A combination of an anionic dye and a nonionic polymer is more preferable.

The amount of the hydrophilic polymer is preferably 0.1 to 5% by mass in the total mass of the ink from the viewpoint of compatibility between the fixing property and the long-term storage stability of the ink, more preferably 0.1 to 4% by mass. 5 to 4% by mass is particularly preferable.
By making the addition amount in the above range, it is more preferable that both the ink (or processing liquid) ejection characteristics of the ink and the fixing property can be achieved.
In addition, the amount of the hydrophilic polymer is preferably 20% by mass or more, more preferably 20 to 150% by mass, and still more preferably 40 to 120% by mass with respect to the mass of the dye described later. 50 to 100% by mass is particularly preferable.
When the addition amount of the hydrophilic polymer is less than 20% by mass relative to the total mass of the dye in the present invention, the fixability may be deteriorated, and when it exceeds 150% by mass, the long-term storage stability of the ink may be deteriorated. .
In the present invention, a combination of preferable examples of the addition amount is more preferable.

  In addition to the dye and the hydrophilic polymer, which are essential components of the inkjet ink of the present invention, water and a water-soluble organic solvent can be added as necessary.

(Water-soluble organic solvent)
As the water-soluble organic solvent, polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, sulfur-containing solvents and the like are used.

  Specific examples of water-soluble organic solvents include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, and glycerin. Can be mentioned.

  Polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diglycerin. And ethylene oxide adducts.

Examples of the nitrogen-containing solvent include pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, and triethanolamine. Examples of the alcohol include alcohols such as ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol.
Examples of the sulfur-containing solvent include thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like.

  In addition, as the water-soluble organic solvent, propylene carbonate, ethylene carbonate, or the like can be used.

  It is preferable to use at least one water-soluble organic solvent. The content of the water-soluble organic solvent is 1 to 60% by mass, preferably 5 to 40% by mass. When the amount of the water-soluble organic solvent in the ink 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 is large. As a result, there are cases where the liquid ejection characteristics become unstable.

(water)
As water, it is preferable to use ion-exchanged water, ultrapure water, distilled water, or ultrafiltered water in order to prevent impurities from being mixed.

(Preferred physical properties of ink)
The surface tension of the ink is preferably 20 to 60 mN / m, more preferably 20 to 50 mN / m, and still more preferably 20 to 35 mN / m. If the surface tension is less than 20 mN / m, ink 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.

  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 viscosity of the ink is preferably 1.2 to 30 mPa · s, more preferably 1.2 to 20 mPa · s, and still more preferably 1.5 to 15 mPa · s. When the viscosity of the ink was larger than 30.0 mPa · s, there was a case where the dischargeability was lowered. On the other hand, when it is smaller than 1.0 mPa · s, there is a case where the jetting property is deteriorated.

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 pH of the ink is preferably 3 or more and 11 or less. More preferably, it is 4 or more and 10.5 or less, and more preferably 4.5 or more and 10 or less. When the pH of the treatment liquid is less than 3 or exceeds 11, there is a case where the ink flow path component of the print head is dissolved and the print head is broken.

<Processing liquid>
In the present invention, the treatment liquid contains at least a flocculant.
Here, the aggregating agent (hereinafter also referred to as “aggregating component”) means a component that insolubilizes or aggregates the components in the ink or rapidly increases the viscosity of the ink.
Hereinafter, the treatment liquid (inkjet treatment liquid of the present invention) will be described in detail.

(Flocculant)
The flocculant is preferably at least one selected from polyvalent metal salts, organic amines, onium salts, organic acids and inorganic acids.

  The aggregating agent is a component that agglomerates insoluble or agglomerates the ink constituents or abruptly increases the viscosity of the ink when mixed with the ink. For example, substances that oxidize and insolubilize anionic groups of hydrophilic polymers (for example, organic acids and inorganic acids), and substances that generate anionic crosslinks with anionic groups of hydrophilic polymers (polyvalent metal salts and organic amines).・ Onium salt).

  Preferred examples of the flocculant having such a function include polyvalent metal salts, organic amines (cationic compounds), onium salts, organic acids, and inorganic acids.

  Examples of the polyvalent metal salt include polyvalent metal ions such as aluminum ions, barium ions, calcium ions, copper ions, iron ions, magnesium ions, manganese ions, nickel ions, tin ions, titanium ions, and zinc ions, and inorganic acids described later. And organic carboxylic acids such as acetic acid, succinic acid, lactic acid, fumaric acid, fumaric acid, citric acid, salicylic acid and benzoic acid, and salts of organic sulfonic acids.

  Specific examples include 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, barium thiocyanate, Calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium benzoate, calcium acetate, calcium salicylate, calcium tartrate, calcium lactate, calcium fumarate, citric acid Calcium, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, iron oxalate, iron lactate, iron fumarate, iron citrate, chloride Magnesium, Magnesium bromide Cium, 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, odor And salts of polyvalent metals such as nickel fluoride, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, zinc thiocyanate, and zinc acetate.

The organic amine 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.

Examples of the onium salts include ammonium salts, sulfonium salts, phosphonium salts, iodonium salts, oxonium salts, and the like.
As an ammonium salt, the compound which has the following structures among the compounds mentioned above is mentioned.

Here, R _{1 to} R ₄ represent hydrogen, an alkyl group, an allyl group, an aryl group, a phenyl group, a saturated or unsaturated carbocyclic group or heterocyclic group, an alkoxy group, an aryloxy group, or an amino group. All the substituents may have a substituent. X ⁻ represents a counter ion.
Examples of the sulfonium salt include compounds having the following structure.

Here, R _{1 to} R ₄ represent hydrogen, an alkyl group, an allyl group, an aryl group, a phenyl group, a saturated or unsaturated carbocyclic group or heterocyclic group, an alkoxy group, an aryloxy group, or an amino group. All the substituents may have a substituent. X ⁻ represents a counter ion.
For example, (2-carboxyethyl) dimethylsulfonium chloride, (2-carboxyethyl) dimethylsulfonium bromide and the like can be mentioned.
Examples of the phosphonium salt include compounds having the following structure.

Here, R _{1 to} R ₄ represent hydrogen, an alkyl group, an allyl group, an aryl group, a phenyl group, a saturated or unsaturated carbocyclic group or heterocyclic group, an alkoxy group, an aryloxy group, or an amino group. All the substituents may have a substituent. X ⁻ represents a counter ion.
For example, n-butyltriphenylphosphonium bromide, (3-carboxypropyl) triphenylphosphonium bromide, methyltriphenyl bromide and the like can be mentioned.
Examples of the iodonium salt include compounds having the following structure.

Here, R _{1 to} R ₄ represent hydrogen, an alkyl group, an allyl group, an aryl group, a phenyl group, a saturated or unsaturated carbocyclic group or heterocyclic group, an alkoxy group, an aryloxy group, or an amino group. All the substituents may have a substituent. X ⁻ represents a counter ion.
For example, diphenyl iodonium chloride, diphenyl iodonium-2-carboxylate monohydrate and the like can be mentioned.
Examples of the oxonium salt include compounds having the following structure.

Here, R _{1 to} R ₄ represent hydrogen, an alkyl group, an allyl group, an aryl group, a phenyl group, a saturated or unsaturated carbocyclic group or heterocyclic group, an alkoxy group, an aryloxy group, or an amino group. All the substituents may have a substituent. X ⁻ represents a counter ion.
Examples thereof include trimethyloxonium tetrafluoroborate and triethyloxonium tetrafluoroborate.

  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 general 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 a hydrogen atom or 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. The compound represented by the general formula (1) may be a saturated ring or an unsaturated ring as long as it is a heterocyclic ring. l is an integer of 1-5.

  Specifically, the compound represented by the general formula (1) has a furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, quinoline structure, and further has a carboxyl group as a functional group. Compounds. 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-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-indolecarboxylic acid, 2,5-dioxo-4-methyl-3-pyrroline-3-propionic acid, 2-pyrrolidinecarboxylic acid, 4-hydroxyproline, 1-methylpyrrolidine-2-carboxylic acid, 5- Carboxy-1-methylpyrrolidine-2-acetic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, pyridinedicarboxylic acid, pyridinetricarboxylic acid, pyridinepentacarboxylic acid, 1,2,5,6- Tetrahydro-1-methylnicotinic acid, 2-quinolinecarboxylic acid, 4-quinolinecarboxylic acid, 2-phenyl-4-quinolinecarboxylic acid, 4-hydroxy-2-quinolinecarboxylic acid, 6-methoxy-4-quinolinecarboxylic acid, etc. The compound of this is mentioned.

  As the organic acids, 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.

  Examples of inorganic acids include hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, and salts thereof.

  Among these aggregating agents, polyvalent metal salts, organic amines, and organic acids are preferable from the viewpoint of satisfactorily aggregating or insolubilizing the polymer and the dye.

The flocculant may be used alone or in combination of two or more. The content of the flocculant is preferably 0.01% by mass or more and 30% by mass or less. 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 is less than 0.01% by mass, the color material is insufficiently aggregated when contacting the ink, and the optical density, bleeding, and intercolor bleeding may be deteriorated. When the amount exceeds 30% by mass, the jetting characteristics are degraded, and the liquid may not be jetted normally.

(Water-soluble organic solvent)
As the treatment liquid, a water-soluble organic solvent similar to the ink can be used.
The content of the water-soluble organic solvent is 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.

(Preferred physical properties of treatment liquid)
The surface tension and viscosity of the treatment liquid may have the same characteristics as the ink.

The pH of the treatment liquid used in combination with the ink containing an anionic dye is preferably 2.5 or more and 7.0 or less. More preferably, it is 2.75 or more and 6.0 or less, More preferably, it is 3.0 or more and 4.5 or less.
When the pH of the treatment liquid was less than 2.5, there was a case where the ink flow path component of the print head was dissolved and the print head was broken. On the other hand, when the pH of the treatment liquid exceeded 7.0, dye aggregation was insufficient at the time of contact with the ink, and optical density, bleeding, and intercolor bleeding were sometimes deteriorated.
On the other hand, the pH of the treatment liquid used in combination with the ink containing the cationic dye is preferably 7 or more and 11 or less. More preferably, it is 7.5 or more and 11 or less, More preferably, it is 8.5 or more and 10.5 or less.
When the pH of the treatment liquid was less than 7, dye aggregation was insufficient at the time of contact with ink, and optical density, bleeding, and intercolor bleeding were sometimes deteriorated. In some cases, the ink flow path component of the print head was dissolved, causing the print head to fail. On the other hand, when the pH of the treatment liquid exceeds 11, there is a case where the ink flow path constituent portion of the print head is dissolved and the print head is broken.

(Additive to ink and processing liquid)
Hereinafter, additives that can be appropriately used for the ink or the treatment liquid will be described.

A surfactant can be added to the ink and the treatment agent.
Examples of these surfactants include various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and the like. Preferably, anionic surfactants and nonionic surfactants are used. An activator is used.

  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, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, etc. can be used, preferably , Dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, monobutylbiphenylsulfonate, dibutylphenylsulfonate Nord disulfonic acid salts and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, poly Oxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkyl alkanolamide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, polyoxyethylene adduct of acetylene glycol Preferably, polyoxyethylene nonyl pheny Ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether (eg, alkyl is 2-ethylhexyl), polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid An alkylolamide, a polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol are used.

  In addition, silicone surfactants such as polysiloxane oxyethylene adducts, fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers, spicrispolic acid and rhamnolipids Biosurfactants such as lysolecithin can also be used.

  These surfactants may be used alone or in combination. Further, the HLB of the surfactant is preferably in the range of 3 to 20 in view of dissolution stability and the like.

  0.001-5 mass% is preferable and, as for the addition amount of these surfactant, 0.01-3 mass% is especially preferable.

The ink or treatment liquid may contain a plasticizer.
When the plasticizer is included, the polymer penetrates between the molecules, softens the polymer, improves the fixability, and obtains excellent abrasion resistance.

  As the plasticizer, known plasticizers for resins can be used without any particular limitation. However, the plasticizer penetrates between the polymers and has plasticity, so that an image having more excellent abrasion resistance can be obtained. Therefore, the difference between the SP value of the plasticizer and the SP value (solubility parameter) of the polymer is preferably 2.0 or less. If the difference in SP value is desirably 1.0 or less, more desirably 0.5 or less, the compatibility between the plasticizer and the polymer further increases, and an image having excellent abrasion resistance can be obtained by film formation. it can. Plasticizers include "Chemical Handbook" (edited by the Chemical Society of Japan, Maruzen), "Plasticizers-Theory and Applications-" (written by Koichi Murai, Koshobo), "Research on plasticizers" "Research" (edited by Polymer Chemistry Association), "Handbook rubber / plastic compounded chemicals" (edited by Rubber Digest Co., Ltd.), etc.

  Here, a value obtained by the Fedors method is used as the SP value. The method of Fedors is described in Fedors, R .; F. , "Polymer Eng. Sci.", 14. P. 147 (1974). Specifically, it was calculated using the following formula.

  In the above formula, ΔE: cohesive energy density, V: molar volume, Δei: atom or atomic group evaporation energy, and Δvi: molar volume. Further, the value of the molar volume in the above formula is obtained as molecular weight / specific gravity. The specific gravity here uses the value at 25 ° C.

  Some plasticizers are described as high-boiling organic solvents and thermal solvents. For example, JP-A-59-83154, 59-178451, 59-178453, and 59-1-78454 are disclosed. 59-178455, 59-178457, 62-174754, 62-245253, 61-209444, 61-200538, 62-8145, 62-9348, 62-30247, 62-136646, 62-174754, 62-245253, 61-209444, 61-200538, 62-8145, 62-9348, 62 -30247, 62-136646, JP-A-2-235694, etc. Luric acid esters, phosphoric acid esters, fatty acid esters, abietic acid esters, adipic acid esters, sebacic acid esters, azelaic acid esters, benzoic acid esters, butyric acid esters, epoxidized fatty acid esters, glycol Acid esters, propionic acid esters, trimellitic acid esters, citric acid esters, sulfonic acid esters, carboxylic acid esters, succinic acid esters, maleic acid esters, fumaric acid esters, phthalic acid esters, Stearic acid esters), amides (for example, fatty acid amides, sulfoamides, etc.), ethers (weight average molecular weight MW 200 or more), alcohols (weight average molecular weight MW 200 or more), lactones And compounds such as polyethyleneoxy That.

  As the plasticizer, a polymer having a relatively low molecular weight can be used. In this case, the molecular weight of the plasticizer is 15000 or less, preferably 5000 or less in terms of weight average molecular weight. Furthermore, oligomers can also be used as plasticizers. In addition to the compounds listed above, commercially available products include, for example, Adeka Sizer PN-170 and PN-1430 manufactured by Asahi Denka Kogyo; P. HALL products PARAPLEX-G-25, G-30, G-40; Rika Hercules products ester gum 8L-JA, ester R-95, pentalin 4851, FK115, 4820, 830, Louisol 28-JA, picolastic A75, pico Examples include Tex LC and Crystallex 3085.

  Further, an aqueous solvent having an SP value of 9 to 11 such as butyl carbitol, diethylene glycol monoethyl ether, triethylene glycol or the like can be used as a plasticizer.

  The plasticizer is preferably at least one selected from the group consisting of aliphatic esters, acetate esters, trimellitic acid esters and orthophosphate esters, more preferably aliphatic esters, butyl carbitol, dimethyl adipate, Diethyl succinate is particularly preferred.

  The plasticizer content is preferably 0.01% by mass or more and 30% by mass or less. More preferably, it is 0.05 mass% or more and 15 mass% or less, More preferably, it is 0.1 mass% or more and 10 mass% or less. When the amount of the plasticizer is too small, there is a case where sufficient flexibility of the polymer cannot be obtained. On the other hand, when the amount is too large, there is a case where the viscosity of the liquid becomes large and the jetting property of the liquid becomes unstable.

  Inks and treatment agents include penetrants for the purpose of adjusting penetrability, polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethylene glycol, ethylcellulose, carboxymethylcellulose, etc. for the purpose of controlling properties such as improving ink ejection properties, conductivity, In order to adjust pH, alkali metal compounds such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc., as necessary, pH buffering agent, antioxidant, antifungal agent, viscosity adjusting agent, conductive agent, An ultraviolet absorber, a chelating agent, and the like can also be added.

(Preferred physical properties of the mixed liquid of ink and treatment liquid)
The viscosity of the mixed liquid of ink and treatment liquid (mass ratio 1: 0.5) is preferably 6.0 mPa · s or more, and more preferably 8.0 to 25.0 mPa · s. . If the viscosity is too low, the optical density may decrease. On the other hand, if the viscosity is too high, it indicates that the cohesive force and the thickening power are too high, and the ink spreading is suppressed and white stripes may occur. .

(Inkjet ink tank)
The ink-jet ink tank of the present invention stores each liquid (the ink-jet ink or the treatment liquid of the present invention) of the ink-jet ink set of the present invention. For example, the ink described in JP-A-2001-138541 Tank 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 ejecting each liquid onto a recording medium using an ink set for ink jet. Specifically, printing is performed so that the ink for ink jet and the processing liquid are in contact with each other. To do.

  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 angles of the ink and the treatment liquid with respect to the recording medium change depending on the drop amount, and it is considered that 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 the case of using an ink jet ink set, the ink jet ink and the treatment liquid are applied on the recording medium so as to come into contact with each other. This is because the ink aggregates due to the action, 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 treatment liquid. This is because the constituent components of the inkjet ink can be effectively aggregated by applying the treatment liquid first. Any ink jet ink may be applied at any time after the treatment liquid is applied. Preferably, it is 0.5 seconds or less after the treatment liquid is applied.

  In the ink jet recording method (apparatus) of the present invention, the mass ratio between the ink application amount and the treatment liquid 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 was too small or too large with respect to the amount of treatment liquid applied, there was a case where aggregation was insufficient, resulting in a decrease in optical density, deterioration in bleeding, and deterioration in intercolor bleeding. . 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 treatment liquid application amount with respect to the ink-jet ink application amount required for forming one pixel is preferably 60% by volume or less, more preferably 5 to 50% by volume, and still more preferably 10 by volume ratio. ~ 30% by 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 ink and processing liquid to the recording head is performed from an ink tank (including a processing liquid tank) filled with each liquid of ink and processing liquid. Is good. The ink tank is preferably a cartridge system that can be attached to and detached from the apparatus, and ink and processing liquid 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. An image forming unit 8 (image forming unit) for forming an image by ejecting ink and processing liquid onto the surface of the recording medium 1; The main ink tank 4 is configured to supply ink and processing liquid to the sub ink tanks 5 of the 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 has sub ink tanks 51, 52, 53, 54, and 55 in which different colors of ink and processing liquid 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 the first liquid, and processing liquid from the main ink tank 4 as the second liquid. Replenished and paid.

  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 the replenishing device 15 replenishes ink or processing liquid 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 different colors of ink and processing liquid are stored. These are filled with, for example, black ink (K), yellow ink (Y), magenta ink (M), and cyan ink (C) as the first liquid, and the processing liquid as the second liquid, Each is stored in the image forming apparatus 100 in a detachable manner.

  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, the nozzle group for discharging each color (including the treatment liquid) is also provided in the same manner as the sub ink tanks 51 to 55 are sequentially arranged in the sub scanning direction (conveyance direction of the recording medium 1: arrow X direction). They are 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.

[Ink and treatment liquid preparation method]
In the examples and comparative examples, the ink and the treatment liquid were prepared as follows.
Various compounds were mixed and stirred so as to have the following ink composition and treatment liquid composition, and then the obtained liquid was passed through a 5 μm filter to obtain a desired ink and treatment liquid.

<Ink A>
・ C. I. Direct Blue 199: 3% by mass
Styrene (St) / n-butyl methacrylate (BMA) / acrylic acid copolymer (KOH salt, acid value = 150, weight average molecular weight 7500): 0.5% by mass
・ Diethylene glycol: 12% by mass
・ Glycerin: 5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion-exchanged water: remainder The ink had a pH of 7.4, a viscosity of 3.3 mPa · s, and a surface tension of 31 mN / m.

<Ink B>
・ C. I. Direct violet 107: 3% by mass
Styrene / lauryl methacrylate / methacrylic acid copolymer (NaOH salt, acid value = 240, average weight molecular weight 4500): 0.6% by mass
・ Diethylene glycol: 12% by mass
Propylene glycol: 6% by mass
Polyoxyethylene 2-ethylhexyl ether: 0.8% by mass
-Ion-exchanged water: remainder The pH of this ink was 7.9, the viscosity was 3.1 mPa.s, and the surface tension was 30 mN / m.

<Ink C>
・ C. I. Direct Red 227: 2.3% by mass
・ C. I. Direct violet 107: 0.9% by mass
・ Polyvinylpyrrolidone: 0.4% by mass
・ Diethylene glycol: 12% by mass
Propylene glycol: 5% by mass
・ Butyl carbitol: 5% by mass
・ Polypropylene glycol ethylene oxide adduct: 1% by mass
-Ion-exchanged water: remainder The ink had a pH of 7.1, a viscosity of 3.1 mPa · s, and a surface tension of 31 mN / m.

<Ink D>
・ C. I. Direct Yellow 86: 3% by mass
・ Diethylene glycol: 15% by mass
・ Glycerin: 4% by mass
・ Polyoxyethylene 2-ethylhexyl ether: 1% by mass
-Ion-exchanged water: remainder The pH of this ink was 7.3, the viscosity was 2.9 mPa · s, and the surface tension was 30 mN / m.

<Processing liquid F>
-Polyallylamine (hydrochloride): 6.5% by mass
・ Diethylene glycol: 6% by mass
・ Glycerin: 2.5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this treatment liquid was 7.8, the viscosity was 2.9 mPa · s, and the surface tension was 30 mN / m.

<Processing liquid G>
2-furancarboxylic acid (sodium salt): 8% by mass
・ 1,5-pentanediol: 10% by mass
2-ethyl-2- (hydroxymethyl) -1,3-propanediol: 2% by mass
・ Polypropylene glycol ethylene oxide adduct: 1% by mass
-Ion exchange water: remainder The pH of this process liquid was 4.5, the viscosity was 3.1 mPa * s, and the surface tension was 31 mN / m.

<Treatment liquid H>
・ Magnesium nitrate: 7% by mass
・ Diethylene glycol: 4% by mass
・ Glycerin: 2.5% by mass
-Acetylene glycol ethylene oxide adduct: 1% by mass
-Ion-exchanged water: remainder The pH of this treatment liquid was 5.5, the viscosity was 2.9 mPa · s, and the surface tension was 32 mN / m.

(Examples 1-3, Comparative Examples 1-3)
Printing was performed using the ink or ink set according to Table 1.
For printing, a 600 dpi, 1024 nozzle prototype print head (14 ng drop amount) is used, and ink or ink set (ink, treatment liquid) is ejected to FX-C ² paper (Fuji Xerox Co., Ltd.) according to the print pattern. I went there. Printing was performed in a general environment (temperature 23 ± 0.5 ° C., humidity 55 ± 5% RH). In the case of ejecting the ink and the treatment liquid, the treatment liquid and the ink were ejected in this order, and the mass ratio of the applied amount of the ink and the treatment liquid for forming one pixel was 1: 0.2.

[Evaluation]
For the ink and the treatment liquid, fixing property, ink jetting stability, gas resistance, water resistance, and drying were performed. The results are shown in Table 1.

(Fixability)
For fixing, white plain paper (C2 paper, manufactured by Fuji Xerox Co., Ltd.) is printed on the printing section, and a weight of 5 kg and a bottom area of 10 cm ² is moved thereon, and the blank paper is moved toward the non-printing section. The degree to which the blank paper and weight were removed and moved to the non-printing part was evaluated. The evaluation criteria are as follows.
◎: The print shift is not apparent. ○: There is a print shift, but I'm almost not interested. △: The print shift is a little anxious. ×: The print shift is worrisome.

(Ink ejection stability)
The ejection stability was judged on the basis of 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.
○: 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

(Gas resistance)
For ozone resistance, a printed matter having a 100% coverage pattern printed thereon was prepared, and the printed matter was exposed for 24 hours under the condition of an ozone concentration of 1.0 ppm. The optical density of the printed matter after the exposure was measured with X-rite 404.
-Evaluation criteria-
○: Ratio of optical density after exposure to initial optical density is 90% or more Δ: Ratio of optical density after exposure to initial optical density is 80% or more ×: Ratio of optical density after exposure to initial optical density is 80% Less than

(water resistant)
After 30 minutes of printing, several drops of ion-exchanged water were dropped on the printed portion with a dropper, and the degree of bleeding was visually observed. The evaluation criteria are as follows.
-Evaluation criteria-
○: There is almost no bleeding of characters. △: There is some bleeding of characters. ×: There is considerable bleeding of characters.

(Drying)
Drying is performed by placing a plain white paper (Fuji Xerox Co., Ltd., C2 paper) on the printing surface 10 seconds after printing, and further placing a weight of 5 kg and a bottom area of 10 cm ² on it for 3 seconds. The weight was removed and the degree of transfer to blank paper was evaluated. The evaluation criteria are as follows.
-Evaluation criteria-
◎: The print shift is not apparent. ○: There is a print shift, but I'm almost not interested. △: The print shift is a little anxious. ×: The print shift is worrisome.

As is apparent from Table 1, it can be seen that Comparative Example 1 in which the treatment liquid does not contain the flocculant and Comparative Examples 2 to 3 in which the ink does not contain the hydrophilic polymer have poor fixability.
On the other hand, in the present invention, it is understood that the fixability is excellent by adding a hydrophilic polymer effective for fixing to the ink and using a treatment liquid containing an aggregating agent. In addition, it was possible to obtain a good ink set with respect to the reliability (ink ejection stability), gas resistance, water resistance, and drying at the head.

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 (7)

An ink-jet ink comprising: an ink containing at least an anionic or cationic water-soluble dye; an ink containing at least one hydrophilic polymer having the same polarity as the dye; or a treatment liquid containing at least an aggregating agent. set. The inkjet ink set according to claim 1, wherein the flocculant is at least one selected from polyvalent metal salts, organic amines, onium salts, organic acids, and inorganic acids. The inkjet ink set according to claim 1 or 2, wherein the amount of the hydrophilic polymer is 0.1 to 5% by mass. The ink-jet ink set according to any one of claims 1 to 3, wherein the amount of the hydrophilic polymer is 20% by mass or more based on the mass of the coloring material. An ink-jet ink tank comprising the ink-jet ink set according to claim 1. A recording method comprising forming an image by applying the ink set according to any one of claims 1 to 4 onto a recording medium. The inkjet ink set according to any one of claims 1 to 4, wherein the inkjet ink set includes a recording head for discharging each liquid in the inkjet ink set to a recording medium. An ink jet recording apparatus characterized by the above.

Images