JP2012241015A - Inkjet recording ink, inkjet recording ink set, ink cartridge, inkjet recording method and recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording ink that comprises a pigment dispersed with a specific anionic surfactant and enhances an image density, an inkjet recording ink set, an ink cartridge comprising a container containing the ink or the ink set, an inkjet recording method using the ink or the ink set, and an inkjet recording apparatus loaded with the ink cartridge.SOLUTION: (1) The inkjet recording ink comprises a pigment dispersion, an anionic surfactant, a water-soluble organic solvent, a neutralizing agent X and water, where the anionic surfactant is a perfluoroalkyl sulfonic acid bearing a 6C alkyl group and gives a 1 wt.% aqueous solution having a pH of 2-3. (2) In the inkjet recording ink (1), the pigment dispersion comprises a pigment dispersion A comprising a pigment dispersed with a surfactant and/or a pigment dispersion B comprising a pigment contained in a polymer.

Description

  The present invention relates to an ink for ink jet recording, an ink set for ink jet recording, an ink cartridge containing the ink or ink set in a container, an ink jet recording method using the ink or ink set, and an ink jet recording apparatus equipped with the ink cartridge. .

In ink jet recording ink in which a pigment is dispersed with a surfactant-type dispersant, a method for improving the image quality by adding a surfactant to the ink is already known. However, conventional surfactants have a problem that it is difficult to improve image density.
For example, Patent Document 1 discloses an ink jet recording ink using a perfluoroalkylsulfonic acid having a specific structure as a surfactant for the purpose of improving the color developability on plain paper. This invention is similar to the present invention in that it uses a perfluoroalkyl sulfonic acid, but uses a perfluoroalkyl sulfonic acid having a structure different from that of the present invention, resulting in poor ink stability over time (viscosity change occurs). ) Has not been solved.

  The present invention relates to an ink for ink jet recording capable of improving image density by dispersing a pigment with a specific anionic surfactant, an ink set for ink jet recording, an ink cartridge containing the ink or ink set in a container, An object is to provide an ink jet recording method using the ink or ink set and an ink jet recording apparatus equipped with the ink cartridge.

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基、及びアラルキル基のいずれかを表す。ｍは０〜７の整数、ｎは２０〜８０の整数を表す。）
６） 前記顔料分散体Ｂのポリマーが、（ａ）塩生成基含有モノマー由来の構成単位、又は、（ａ）塩生成基含有モノマー由来の構成単位と（ｃ）疎水性モノマー由来の構成単位を主鎖に有し、（ｂ）マクロマー由来の構成単位を側鎖に有するグラフトポリマーである２）〜５）のいずれかに記載のインクジェット記録用インク。
７） ４）に記載のインクジェット記録用インクと５）に記載のインクジェット記録用インクからなるインクジェット記録用インクセット。
８） １）〜７）のいずれかに記載のインクジェット記録用インク又はインクジェット記録用インクセットを容器に収容したインクカートリッジ。
９） １）〜７）のいずれかに記載のインクジェット記録用インク又はインクジェット記録用インクセットに刺激を印加し、該インクを飛翔させて画像を形成することを特徴とするインクジェット記録方法。
１０） ８）に記載のインクカートリッジを搭載し、インクに刺激を印加し飛翔させて画像を形成するインク飛翔手段を有することを特徴とするインクジェット記録装置。 The above problems are solved by the following inventions 1) to 10).
1) Contains a pigment dispersion, an anionic surfactant, a water-soluble organic solvent, a neutralizing agent X, and water, and the anionic surfactant has an alkyl group having a pH of 2 to 3% by weight and an alkyl group. An ink for ink-jet recording, which is a perfluoroalkylsulfonic acid having 6 carbon atoms.
2) The pigment dispersion is composed of pigment dispersion A in which a pigment is dispersed with a surfactant and / or pigment dispersion B in which the pigment is contained in a polymer. Ink for ink jet recording.
3) The ink for inkjet recording according to 1) or 2), wherein the neutralizing agent X is 2-amino-2-ethyl-1,3-propanediol.
4) The ink for inkjet recording according to 2) or 3), wherein the pigment of the pigment dispersion A is carbon black and the surfactant is a sodium naphthalene sulfonate formalin condensate.
5) The pigment dispersion A is any one of a yellow pigment, a magenta pigment, and a cyan pigment, and the surfactant is a compound represented by the following general formula (1): 2) or 3 Ink for ink jet recording described in the above.

(In the formula, R represents any of an alkyl group having 1 to 20 carbon atoms, an allyl group, and an aralkyl group. M represents an integer of 0 to 7, and n represents an integer of 20 to 80.)
6) The polymer of the pigment dispersion B comprises (a) a structural unit derived from a salt-forming group-containing monomer, or (a) a structural unit derived from a salt-forming group-containing monomer and (c) a structural unit derived from a hydrophobic monomer. The ink for inkjet recording according to any one of 2) to 5), which is a graft polymer having a main chain and (b) a macromer-derived structural unit in a side chain.
7) An ink set for ink jet recording comprising the ink for ink jet recording described in 4) and the ink for ink jet recording described in 5).
8) An ink cartridge containing the ink for ink jet recording or the ink set for ink jet recording according to any one of 1) to 7) in a container.
9) An ink jet recording method comprising applying an stimulus to the ink for ink jet recording or the ink set for ink jet recording according to any one of 1) to 7) and flying the ink to form an image.
10) An ink jet recording apparatus comprising the ink cartridge according to 8), and having an ink flying unit that forms an image by applying a stimulus to the ink to fly.

  According to the present invention, an ink for ink jet recording capable of improving image density, an ink set for ink jet recording, and an ink containing the ink or ink set in a container, in which a pigment is dispersed with a specific anionic surfactant. A cartridge, an ink jet recording method using the ink or ink set, and an ink jet recording apparatus equipped with the ink cartridge can be provided.

It is the schematic including the case (exterior) of an example of an ink cartridge. It is the schematic which shows an example of an inkjet recording device.

Hereinafter, the present invention will be described in detail.
The ink for inkjet recording of the present invention (hereinafter also referred to as “ink”) is a perfluoroalkylsulfonic acid (hereinafter referred to as “anionic surfactant”) having a 1 wt% aqueous solution having a pH of 2 to 3 and an alkyl group having 6 carbon atoms. (Also referred to as “perfluoroalkylsulfonic acid α”). Since the perfluoroalkylsulfonic acid α has a low surface tension, it can reduce the dynamic surface tension of the ink, improve the permeability of the ink when the ink lands on the recording medium, and improve the image density.
The addition amount of perfluoroalkylsulfonic acid α is preferably 1.0% by weight or less based on the total weight of the ink. If it exceeds 1.0% by weight, the storage stability may be lowered. In particular, when an amount such that the surface tension of the ink is 20 to 30 mN / m is added, the spreading of the ink droplet when the ink droplet lands is appropriate, and a sufficient image density can be obtained. Examples of commercially available products of perfluoroalkylsulfonic acid α include FS-10 manufactured by Dupont.

In the ink of the present invention, a pigment is contained as a pigment dispersion. Examples of the pigment dispersion include pigment dispersion A in which a pigment is dispersed with a surfactant and pigment dispersion B in which a pigment is contained in a polymer. These may be used alone or in combination. When used in combination, the blending ratio of the pigment dispersion A and the pigment dispersion B is preferably 1: 9 to 9: 1 by weight, and more preferably 2: 8 to 8: 2.
When carbon black is used as the pigment of the pigment dispersion A, it is preferable to use a sodium naphthalene sulfonate formalin condensate, which is a surfactant, as the dispersant.
The added amount is preferably 0.1 to 2 parts by weight, more preferably 0.25 to 1 part by weight, based on 1 part by weight of carbon black. As a result, an ink having a high image density and good ejection stability and liquid stability can be obtained. If the addition amount is less than 0.1 parts by weight, it is difficult to obtain the effects of the present invention and the storage stability of the aqueous pigment dispersion and the ink is inferior, and as a result, nozzle clogging tends to occur. If the amount exceeds the parts by weight, the viscosity of the aqueous pigment dispersion and the ink tends to be too high, and recording by the ink jet method tends to be difficult.
The total content of the dimer, trimer and tetramer of naphthalenesulfonic acid in the sodium naphthalenesulfonate formalin condensate is preferably 20 to 80% by weight based on the total sodium naphthalenesulfonate formalin condensate, 35 to 65% by weight is more preferable.

The content of carbon black in the ink is preferably 1 to 20% by weight, more preferably 3 to 15% by weight. If the content is less than 1% by weight, the image density is low and the printed image may lack sharpness. If the content is more than 20% by weight, the viscosity of the ink tends to increase and nozzle clogging tends to occur. Sometimes.
Examples of the carbon black include carbon black produced by a gas black method, a furnace method, and a channel method, and among these, the gas black method is particularly preferable.
Examples of commercially available carbon black include # 45L, MCF88, # 990, MA600, # 850 (manufactured by Mitsubishi Chemical Corporation); NIPEX90, NIPEX150, NIPEX160, NIPEX170, NIPEX180, Color Black FW200, Printex25, Special Black 250 (manufactured by Special Black 250) ); REGAL400R, REGAL600R, MOGUL L (manufactured by Cabot Corporation), and the like.
The average primary particle size of carbon black is preferably 10.0 to 30.0 nm, and more preferably 15.0 to 20.0 nm. The BET surface area is preferably 100 to 400 m ² / g, more preferably 150 to 300 m ² / g.

<Production of Black Pigment Dispersion A>
Pigment dispersion A using carbon black is prepared by premixing carbon black, sodium naphthalene sulfonate formalin condensate and water, then dispersing with a bead mill disperser, etc., and then centrifuging coarse particles with a centrifuge. Can be manufactured.
Examples of commercially available products of sodium naphthalene sulfonate formalin condensate include PIONEIN A-45-PN manufactured by Takemoto Yushi Co., Ltd.

（式中、Ｒは炭素数１〜２０のアルキル基、アリル基、及びアラルキル基のいずれかを表す。ｍは０〜７の整数、ｎは２０〜８０の整数を表す。） <Production of Color Pigment Dispersion A>
When a yellow pigment, a magenta pigment, or a cyan pigment is used as the pigment of the pigment dispersion A, it is preferable to use a compound represented by the following general formula (1) as a surfactant.
In order to disperse the pigment satisfactorily, a surfactant (dispersant) different from that for carbon black is used.

(In the formula, R represents any of an alkyl group having 1 to 20 carbon atoms, an allyl group, and an aralkyl group. M represents an integer of 0 to 7, and n represents an integer of 20 to 80.)

In the said General formula (1), n is an integer of 20-80, and 30-50 are preferable. When n is less than 20, the dispersion stability tends to be lowered, and an ink containing a pigment having a large average particle diameter is obtained, so that satisfactory saturation may not be obtained. On the other hand, if it exceeds 80, the viscosity of the ink becomes high and it may be difficult to perform recording by the ink jet recording method.
Thus, by including a polyoxyethylene group as a hydrophilic group, the charge on the pigment surface can be maintained well.
Examples of the alkyl group having 1 to 20 carbon atoms in R include a methyl group, an ethyl group, a propyl group, a butyl group, and an isopropyl group.
Examples of the aralkyl group in R include benzyl, phenethyl, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl and the like.
Examples of the compound represented by the general formula (1) include polyoxyethylene (n = 20) -β-naphthyl ether, polyoxyethylene (n = 40) -β-naphthyl ether, polyoxyethylene (n = 60) -β-naphthyl ether and the like. Among these, polyoxyethylene (n = 40) -β-naphthyl ether is particularly preferable.
The content of the compound represented by the general formula (1) is preferably 0.1 to 0.5 parts by weight with respect to 1 part by weight of the pigment in the ink. When the content is less than 0.1 parts by weight, the pigment is not sufficiently dispersed, and when the content exceeds 0.5 parts by weight, the viscosity of the ink becomes high, making it difficult to record in the ink jet recording system. May be.

  There is no restriction | limiting in particular as said yellow pigment, According to the objective, it can select suitably, for example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, and the like.

The magenta pigment is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.
The pigment that can be used in the cyan ink is not particularly limited and may be appropriately selected depending on the purpose. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

The pigment contained in each ink used in the present invention may be newly produced for the present invention.
If Pigment Yellow 74 is used as the yellow pigment, Pigment Red 122, Pigment Bio Red 19 as the magenta pigment, and Pigment Blue 15: 3 as the cyan pigment, an ink having excellent color tone and light resistance and well-balanced can be obtained. .
The content of the pigment in the ink is preferably 0.1 to 50.0% by weight, and more preferably 0.1 to 20.0% by weight.
The volume average particle diameter (D ₅₀ ) of the pigment is preferably 150 nm or less, and more preferably 100 nm or less. Here, the volume average particle diameter is a value measured by a dynamic light scattering method using a Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.
The color pigment dispersion A is obtained by premixing the pigment, the surfactant represented by the general formula (1) and water, and then dispersing the pigment with a stirrer such as a bead mill.

Examples of the polymer used for the pigment dispersion B include a vinyl polymer, a polyester polymer, and a polyurethane polymer. Among these, from the viewpoint of dispersion stability of water-based ink, a vinyl polymer (hereinafter also referred to as “vinyl polymer”) obtained by addition polymerization of a vinyl monomer (vinyl compound, vinylidene compound, vinylene compound) is used. It is preferable.
The vinyl polymer includes (a) a salt-forming group-containing monomer (hereinafter also referred to as “(a) component”), (b) a macromer (hereinafter also referred to as “(b) component”) and / or (c) a hydrophobic monomer. A polymer obtained by copolymerizing a monomer mixture (hereinafter also referred to as “component (c)”) (hereinafter also referred to as “monomer mixture”) is preferable. This polymer has a structural unit derived from the component (a), a structural unit derived from the component (b) and / or a structural unit derived from the component (c).
A more preferred vinyl polymer has a structural unit derived from component (a), or a structural unit derived from component (a) and a structural unit derived from component (c) in the main chain, and a structural unit derived from component (b). It is a graft polymer in the side chain.

(A) Salt-forming group-containing monomer The salt-forming group-containing monomer is used to increase the dispersion stability of the resulting aqueous dispersion. Examples of the salt-forming group include a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, an amino group, and an ammonium group, and a carboxylic acid group is particularly preferable.
Examples of the salt-forming group-containing monomer include cationic monomers and anionic monomers described in paragraph [0022] of JP-A-9-286939.
Representative examples of the cationic monomer include unsaturated amine-containing monomers and unsaturated ammonium salt-containing monomers. Among these, N, N-dimethylaminoethyl (meth) acrylate, N- (N ′, N′-dimethylaminopropyl) (meth) acrylamide and vinylpyrrolidone are preferable.
Representative examples of anionic monomers include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers, unsaturated phosphoric acid monomers, and the like. Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid. Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylate, bis- (3-sulfopropyl) -itaconic acid ester, and the like. Examples of unsaturated phosphoric acid monomers include vinylphosphonic acid, vinyl phosphate, bis (methacryloyloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate, etc. Is mentioned.
Among the anionic monomers, unsaturated carboxylic acid monomers are preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoints of dispersion stability and ejection stability.

(B) Macromer A macromer is used to increase the dispersion stability of polymer particles, particularly when the polymer particles contain a colorant. The macromer includes a macromer which is a monomer having a polymerizable unsaturated group having a number average molecular weight of 500 to 100,000, preferably 1,000 to 10,000. The number average molecular weight of the macromer can be measured using polystyrene as a standard substance by gel chromatography using chloroform containing 1 mmol / L dodecyldimethylamine as a solvent.
Among the macromers, a styrene macromer and an aromatic group-containing (meth) acrylate macromer having a polymerizable functional group at one end are preferable from the viewpoint of dispersion stability of the colorant-containing polymer particles.
Examples of the styrenic macromer include a styrene monomer homopolymer or a copolymer of a styrene monomer and another monomer. Examples of the styrene monomer include styrene, 2-methylstyrene, vinyl toluene, ethyl vinyl benzene, vinyl naphthalene, chlorostyrene, and the like.
Examples of the aromatic group-containing (meth) acrylate-based macromer include a homopolymer of an aromatic group-containing (meth) acrylate or a copolymer thereof with another monomer. As an aromatic group-containing (meth) acrylate, an arylalkyl having 7 to 22 carbon atoms, preferably 7 to 18 carbon atoms, more preferably 7 to 12 carbon atoms, which may have a substituent containing a hetero atom. (Meth) acrylate having an aryl group having 6 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, which may have a group or a substituent containing a hetero atom In addition, examples of the substituent containing a hetero atom include a halogen atom, an ester group, an ether group, and a hydroxy group. Examples include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, and benzyl (meth) acrylate is particularly preferable.

The polymerizable functional group present at one end of the macromer is preferably an acryloyloxy group or a methacryloyloxy group, and the other monomer to be copolymerized is preferably acrylonitrile.
The content of the styrene monomer in the styrene macromer or the aromatic group-containing (meth) acrylate in the aromatic group-containing (meth) acrylate macromer is preferably 50% by weight from the viewpoint of increasing the affinity with the pigment. Above, more preferably 70% by weight or more.
The macromer may have a side chain composed of another structural unit such as an organopolysiloxane. This side chain can be obtained, for example, by copolymerizing a silicone macromer having a polymerizable functional group at one end represented by the following general formula.
_{CH 2 = C (CH 3)} -COOC 3 H 6 - [Si _{(CH 3) 2} O] t-Si _{(CH 3)} 3
(In the formula, t represents a number of 8 to 40.)
Examples of commercially available styrenic macromers include AS-6 (S), AN-6 (S), and HS-6 (S) manufactured by Toa Gosei Co., Ltd.

(C) Hydrophobic monomer Hydrophobic monomers are used to improve printing density. Examples of hydrophobic monomers include alkyl (meth) acrylates and aromatic group-containing monomers.
As the alkyl (meth) acrylate, those having an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms are preferable. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meta) ) Acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) Examples include decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, and (iso) stearyl (meth) acrylate.
In the present invention, “(iso or tertiary)” and “(iso)” mean both cases in which these groups are present and those in which these groups are not present. Show. “(Meth) acrylate” indicates acrylate, methacrylate, or both.

The aromatic group-containing monomer has an aromatic group having 6 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, which may have a substituent containing a hetero atom. Vinyl monomers are preferable, and examples thereof include the same styrene monomers, aromatic group-containing (meth) acrylates, and monomers containing heteroatoms exemplified in the description of (b) macromer.
In the above, a styrene-type monomer (c-1 component) is preferable from a viewpoint of a printing density improvement, and especially styrene and 2-methylstyrene are preferable as a styrene-type monomer. The content of the component (c-1) in the component (c) is preferably 10 to 100% by weight, more preferably 20 to 80% by weight, from the viewpoint of improving printing density. Moreover, as an aromatic group containing (meth) acrylate (c-2) component, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, etc. are preferable. The content of the component (c-2) in the component (c) is preferably 10 to 100% by weight, more preferably 20 to 80% by weight, from the viewpoint of improving printing density and gloss.
Moreover, it is also preferable to use (c-1) component and (c-2) component together.

In addition to the components (a) to (c), the monomer mixture may further contain a hydroxyl group-containing monomer (hereinafter also referred to as “component (d)”). The hydroxyl group-containing monomer is used for further improving the dispersion stability.
Examples thereof include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polyethylene glycol (n = 2 to 30, n represents the average number of moles added of oxyalkylene groups, and the same applies hereinafter). And (meth) acrylate, polypropylene glycol (n = 2 to 30) (meth) acrylate, poly [ethylene glycol (n = 1 to 15) / propylene glycol (n = 1 to 15)] (meth) acrylate, and the like. Among these, 2-hydroxyethyl (meth) acrylate, polyethylene glycol monomethacrylate, and polypropylene glycol methacrylate are preferable.

The monomer mixture may contain a monomer represented by the following general formula (hereinafter also referred to as “component (e)”) in order to further improve the ejection properties.
_{CH 2 = C (R1) COO} (R2O) qR3
(In the formula, R1 is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, R2 is a divalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom, and R3 is a hetero atom. C 1-30 monovalent hydrocarbon group which may have, q means the average number of added moles, and represents an integer of 1-60, preferably an integer of 1-30.)
In the above general formula, examples of the hetero atom include a nitrogen atom, an oxygen atom, a halogen atom, and a sulfur atom.
Preferable examples of R1 include a methyl group, an ethyl group, and an (iso) propyl group.
Preferred examples of R2O include an oxyethylene group, an oxytrimethylene group, an oxypropane-1,2-diyl group, an oxytetramethylene group, an oxyheptamethylene group, an oxyhexamethylene group, and combinations of two or more thereof. Examples thereof include oxyalkanediyl groups having 2 to 7 carbon atoms (oxyalkylene groups).
Preferable examples of R3 include aliphatic alkyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, alkyl groups having 7 to 30 carbon atoms having an aromatic ring, and 4 to 30 carbon atoms having a heterocyclic ring. An alkyl group etc. are mentioned.

(E) As a specific example of a component, methoxypolyethyleneglycol [1-30: The value of q in the said general formula is shown. Hereinafter, the same) (meth) acrylate, methoxypolytetramethylene glycol (1-30) (meth) acrylate, ethoxypolyethylene glycol (1-30) (meth) acrylate, octoxypolyethylene glycol (1-30) (meth) acrylate , Polyethylene glycol (1-30) (meth) acrylate-2-ethylhexyl ether, (iso) propoxypolyethylene glycol (1-30) (meth) acrylate, butoxypolyethylene glycol (1-30) (meth) acrylate, methoxypolypropylene glycol (1-30) (meth) acrylate, methoxy (ethylene glycol / propylene glycol copolymer) (1-30, ethylene glycol: 1 to 29 therein) (meth) acrylate, and the like. Among these, octoxypolyethylene glycol (1-30) (meth) acrylate and polyethylene glycol (1-30) (meth) acrylate-2-ethylhexyl ether are preferable.
Commercially available products include Shin-Nakamura Chemical Co., Ltd. polyfunctional acrylate monomer (NK ester) M-40G, 90G, and 230G, Nippon Oil &Fats's Blemmer series, PE-90, 200, 350, PME- 100, 200, 400, 1000, PP-500, 800, 1000, AP-150, 400, 550, 800, 50PEP-300, 50POEP-800B, 43PAPE600B, and the like.

The components (a) to (e) can be used alone or in admixture of two or more.
In the production of the vinyl polymer, the content of the above components (a) to (e) in the monomer mixture (content as an unneutralized amount; the same applies hereinafter) or the components (a) to (e) in the vinyl polymer The content of the derived structural unit is as follows.
The content of the component (a) is preferably 2 to 40% by weight, more preferably 2 to 30% by weight, and particularly preferably 3 to 20% by weight, from the viewpoint of dispersion stability of the obtained water dispersion.
The content of the component (b) is preferably 1 to 25% by weight, more preferably 5 to 20% by weight, particularly from the viewpoint of enhancing the interaction with the colorant and improving the dispersion stability.
The content of the component (c) is preferably 5 to 98% by weight, more preferably 10 to 60% by weight, from the viewpoint of improving print density.
The content of component (d) is preferably 5 to 40% by weight, more preferably 7 to 20% by weight, from the viewpoint of dispersion stability of the resulting dispersion.
The content of the component (e) is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, from the viewpoint of improving dischargeability.
The total content of [(a) component + (d) component] in the monomer mixture is preferably 7 to 60% by weight, more preferably 10 to 50% by weight, from the viewpoint of dispersion stability of the resulting dispersion. is there. The total content of [component (a) + component (e)] is preferably 7 to 75% by weight, more preferably 13 to 50% by weight, from the viewpoint of dispersion stability and dischargeability of the resulting dispersion. . The total content of [component (a) + component (d) + component (e)] is preferably 12 to 60% by weight, more preferably 7 to 7% from the viewpoint of dispersion stability and print density of the resulting dispersion. 50% by weight.
The weight ratio of [(a) component / [(b) component + (c) component]] is preferably 0.01 to 1, more preferably from the viewpoint of dispersion stability and print density of the resulting dispersion. Is 0.02 to 0.67, more preferably 0.03 to 0.50.

<Manufacture of polymer>
The polymer can be produced by copolymerizing a monomer mixture by a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method. Among these polymerization methods, the solution polymerization method is preferable.
The solvent used in the solution polymerization method is not particularly limited, but a polar organic solvent is preferable. When the polar organic solvent is miscible with water, it can be used by mixing with water.
Examples of polar organic solvents include aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol, and propanol; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); esters such as ethyl acetate; Is mentioned. Among these, methanol, ethanol, acetone, MEK, MIBK, or a mixed solvent of one or more of these and water is preferable.
In the polymerization, azo compounds such as 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), t-butyl peroxyoctate, dibenzoyl oxide, etc. Known radical polymerization initiators such as organic peroxides can be used. The amount of radical polymerization initiator is preferably 0.001 to 1 mole of the monomer mixture.
5 moles, more preferably 0.01 to 2 moles.
In the polymerization, a known polymerization chain transfer agent such as mercaptans such as octyl mercaptan and 2-mercaptoethanol and thiuram disulfide may be further added.

Since the polymerization conditions of the monomer mixture vary depending on the type of radical polymerization initiator, monomer, and solvent used, it cannot be determined unconditionally. Usually, the polymerization temperature is preferably 30 to 100 ° C, more preferably 50 to 80 ° C, and the polymerization time is preferably 1 to 20 hours. The polymerization atmosphere is preferably a nitrogen gas atmosphere or an inert gas atmosphere such as argon.
After completion of the polymerization reaction, the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation or solvent distillation. Further, the obtained polymer can be purified by repeating reprecipitation or by removing unreacted monomers and the like by membrane separation, chromatographic method, extraction method and the like.
The weight average molecular weight of the polymer used in the present invention is preferably from 5,000 to 500,000, more preferably from 10,000 to 400,000, from the viewpoint of printing density, glossiness, and dispersion stability of the colorant, and preferably from 10,000 to 30 Is more preferable, and 20,000 to 300,000 is particularly preferable. In addition, the weight average molecular weight of a polymer is measured by the method shown in the Example mentioned later.

When the polymer used in the present invention has a salt-forming group derived from the component (a), it is neutralized with a neutralizing agent. As the neutralizing agent, an acid or a base can be used depending on the type of the salt-forming group in the polymer. For example, hydrochloric acid, acetic acid, propionic acid, phosphoric acid, sulfuric acid, lactic acid, succinic acid, glycolic acid, gluconic acid, glyceric acid and other acids, lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, methylamine, dimethylamine , Bases such as trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine, and tributylamine.
The degree of neutralization of the salt-forming group is preferably 10 to 200%, more preferably 20 to 150%, and particularly preferably 50 to 150%.
Here, the degree of neutralization can be determined by the following formula when the salt-forming group is an anionic group.
{[Weight of neutralizing agent (g) / equivalent of neutralizing agent] / [acid value of polymer (KOH mg / g) ×
Polymer weight (g) / (56 × 1000)]} × 100
When the salt-forming group is a cationic group, it can be determined by the following formula.
{[Weight of neutralizer (g) / equivalent of neutralizer] / [amine number of polymer (HCl mg / g) × weight of polymer (g) / (36.5 × 1000)]} × 100
The acid value and amine value can be calculated from the structural unit of the polymer. It can also be determined by a method in which a polymer is dissolved in an appropriate solvent (for example, MEK) and titrated. The acid value or amine value of the polymer is preferably 50 to 200, more preferably 50 to 150.

<Production of Pigment Dispersion B>
The pigment-containing polymer particles used in the pigment dispersion B are preferably obtained as an aqueous dispersion by a method including the following steps (1) and (2).
(1) Step of dispersing a mixture containing a polymer, an organic solvent, a pigment and water (2) Step of removing the organic solvent to obtain an aqueous dispersion containing the pigment In step (1), first, the polymer is organic A method in which an oil-in-water type dispersion is obtained by dissolving in a solvent and then adding a pigment, water and, if necessary, a neutralizing agent, a surfactant and the like and mixing them is preferred.
In the mixture, the proportion of the pigment is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, the proportion of the organic solvent is preferably 10 to 70% by weight, more preferably 10 to 50% by weight, and the proportion of the polymer is It is preferably 2 to 40% by weight, more preferably 3 to 20% by weight, and the ratio of water is preferably 10 to 70% by weight, more preferably 20 to 70% by weight.

When the polymer has a salt-forming group, it is preferable to use a neutralizing agent, and it is usually preferable that the finally obtained aqueous dispersion has a pH of 4.5 to 10. The pH can also be determined by the desired degree of neutralization of the polymer. Examples of the neutralizing agent include those described above. Further, the water-insoluble graft polymer may be neutralized in advance.
Examples of the organic solvent include alcohol solvents such as ethanol, isopropanol and isobutanol, ketone solvents such as acetone, MEK, MIBK and diethyl ketone, and ether solvents such as dibutyl ether, tetrahydrofuran and dioxane.
As the organic solvent, those having a dissolution amount in 100 g of water of 20 to 80 g are preferable, and those having 10 to 50 g are more preferable. In particular, MEK and MIBK are preferable.

There is no restriction | limiting in particular in the dispersion method of the mixture in process (1). The average particle size of the polymer particles can be atomized to a desired particle size only by this dispersion, but preferably after pre-dispersion, this dispersion is further performed by applying a shear stress to obtain the average particle size of the polymer particles. It is preferable to control to obtain a desired particle size. The dispersion in the step (1) is preferably performed at 5 to 50 ° C, more preferably 10 to 35 ° C.
When preliminarily dispersing the mixture, a commonly used mixing and stirring device such as an anchor blade can be used. Among the mixing and stirring devices, high-speed stirring and mixing devices such as Ultra Disper (manufactured by Asada Tekko Co., Ltd.), Ebara Milder (manufactured by Ebara Seisakusho), and TK Homomixer (manufactured by Primics) are preferable.
Examples of means for applying the shear stress of this dispersion include a kneader such as a roll mill, a bead mill, a kneader, and an extruder, a high pressure homogenizer (manufactured by Izumi Food Machinery), and a homovalve represented by a minilab 8.3H type (manufactured by Rannie). Examples of the high-pressure homogenizer include a chamber type high-pressure homogenizer, a microfluidizer (manufactured by Microfluidics), and a nanomizer (manufactured by Nanomizer).
A plurality of these apparatuses may be used in combination, but in the case of a pigment, a high-pressure homogenizer is preferable from the viewpoint of reducing the particle size of the pigment.

In the step (2), an aqueous dispersion of pigment-containing polymer particles can be obtained by distilling off the organic solvent from the obtained dispersion by a known method to form an aqueous system.
The organic solvent in the aqueous dispersion containing the obtained polymer particles is preferably substantially removed, but may remain as long as the object of the present invention is not impaired. The amount of the residual organic solvent is preferably 0.1% by weight or less, and more preferably 0.01% by weight or less.
The obtained aqueous dispersion of pigment-containing polymer particles is obtained by dispersing a solid content of a pigment-containing polymer in water as a main solvent. Here, the form of the pigment-containing polymer particles is not particularly limited as long as the particles are formed of at least a pigment and a polymer. For example, a particle form in which the pigment is included in the polymer, a particle form in which the pigment is uniformly dispersed in the polymer, a particle form in which the pigment is exposed on the polymer particle surface, and the like are included.

The water-soluble organic solvent is used for improving the moisture retention and ejection stability of the ink.
The added amount in the ink is preferably 20 to 40% by weight. If the addition amount is within this range, the ink thickening due to moisture evaporation is suppressed in the ink jet recording apparatus, and when landing on the recording medium, image blurring is suppressed due to ink thickening due to moisture evaporation and high-quality recording is performed. You can get things. If the addition amount is less than 20% by weight, the water in the ink tends to evaporate, and the ink is thickened due to the evaporation of water in the ink supply system in the ink jet recording apparatus, and the ink may be clogged. On the other hand, if the amount added is more than 40% by weight, it may be necessary to reduce the solid content such as pigment or resin in order to make the ink have a desired viscosity, and the image density of the recorded matter may be reduced. Even when the ink lands on the medium, it is difficult for the ink to thicken, and bleeding tends to occur.

Examples of the water-soluble organic solvent include, but are not limited to, the following.
Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,3-butylene glycol, 3-methyl-1,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl -1,3-hexanediol, glycerin, 1,2,3-butanetriol, 1,2,4-butanetriol, polyhydric alcohols such as 1,2,6-hexanetriol, petriol, ethylene glycol monoethyl Ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol Polyhydric alcohol alkyl ethers such as ethyl monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, amides such as formamide, N-methylformamide, N, N-dimethylformamide, monoethanolamine, Amines such as diethanolamine and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate, ethylene carbonate and the like. These can be used alone or in admixture of two or more.
Among these, when 1,3-butylene glycol, diethylene glycol, triethylene glycol, and glycerin are included, an excellent effect is obtained in preventing discharge failure due to water evaporation.

A neutralizing agent X is added to the ink of the present invention for the purpose of preventing the metal member in the ink jet recording apparatus from being deteriorated by the ink. This neutralizing agent X is different from the neutralizing agent for the polymer having a salt-forming group derived from the component (a) described above.
Examples of the neutralizing agent X include 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, and the like. Ethyl-1,3-propanediol is preferred.

If necessary, a resin emulsion may be added to the ink of the present invention to improve dispersion stability. The addition amount is preferably 0.5 to 5.0% by weight in terms of solid content. If it is less than 0.5% by weight, the dispersion stability function may not be sufficiently exhibited. On the other hand, if it exceeds 5.0% by weight, the amount of solid content in the ink increases and the viscosity of the ink increases, making it difficult to eject.
Examples of commercially available products include SF460, SF460S, SF420, SF110, SF300, SF361 (urethane resin emulsion; all manufactured by Nihon Unicar), W5025, W5661 (urethane resin emulsion; manufactured by Mitsui Takeda Chemical), and the like. .

To the ink of the present invention, as other components, a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, an antioxidant and the like can be appropriately added as necessary.
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared, and any substance can be used according to the purpose. Examples thereof include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide, quaternary ammonium hydroxide, quaternary Examples thereof include phosphonium hydroxide, carbonates of alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate.
Examples of the antiseptic / antifungal agent include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, and sodium pentachlorophenol. Can be mentioned.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.
Examples of the antioxidant include phenol-based antioxidants (including hindered phenol-based antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

The ink or ink set of the present invention is preferably housed in a container and used as an ink cartridge. This eliminates the need to touch the ink directly, so that it is possible to prevent soiling of hands and clothes, and the handling work for refilling ink can be simplified.
The ink cartridge accommodates ink in a container and has other members and the like appropriately selected as necessary. The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, a container having an ink bag formed of an aluminum laminate film, a resin film, etc. Are preferable.
An example of the ink cartridge will be described with reference to FIG.
The ink cartridge (200) fills the ink bag (241) with ink from the ink inlet (242) and exhausts it, and then closes the ink inlet (242) by fusing. In use, ink is supplied to the apparatus by inserting a needle of the apparatus main body into an ink discharge port (243) made of a rubber member. The ink bag (241) is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 1, the ink bag (241) is usually housed in a plastic cartridge case (244) and is detachably mounted on various ink jet recording apparatuses.
The ink cartridge (200) accommodates ink and can be used by being detachably attached to various ink jet recording apparatuses. It is preferable that the ink cartridge (200) is also detachably attached to the ink jet recording apparatus of the present invention described later. .

(Inkjet recording method and inkjet recording apparatus)
The inkjet recording method of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.
The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.
-Ink flying process and ink flying means-
The ink flying process is a process of forming an image on a recording medium by applying a stimulus (energy) to the ink and causing it to fly.
The ink flying means is a means for forming an image on a recording medium by applying a stimulus (energy) to the ink and causing the ink to fly. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

In the present invention, it is preferable that at least a part of the liquid chamber portion, the fluid resistance portion, the diaphragm, and the nozzle member of the ink jet head are formed of a material containing silicone or nickel. The diameter of the inkjet nozzle is preferably 30 μm or less, and more preferably 1 to 20 μm.
The stimulus (energy) can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose. Heat (temperature), pressure, vibration, and light Etc. These may be used individually by 1 type and may use 2 or more types together. Of these, heat and pressure are preferred.
Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, Examples include thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, electrostatic actuators that use electrostatic force, etc. It is done.

There is no particular limitation on the mode of ink flying, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the heat corresponding to the recording signal is applied to the recording ink in the recording head. Examples include a method in which energy is applied using, for example, a thermal head, bubbles are generated in the ink by the thermal energy, and ink is ejected and ejected as droplets from the nozzle holes of the recording head by the pressure of the bubbles. .
Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting ink as droplets from the nozzle holes of the recording head.
The size of the ink droplets to be ejected is preferably, for example, 3 × 10 ⁻¹⁵ to 40 × 10 ⁻¹⁵ m ³ ( ³ to 40 pL), and the ejection jet speed is 5 to 20 m / s. The drive frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

The ink jet recording apparatus of the present invention includes the ink cartridge and a head that performs recording by discharging ink.
Examples of the printing (discharge) method include a continuous jet type and an on-demand type. Further, examples of the on-demand type include a piezo method, a thermal method, and an electrostatic method.
An example of the ink jet recording apparatus of the present invention will be described with reference to FIG.
In FIG. 2, the ink cartridge 20 in which the ink for ink jet recording of the present invention is accommodated is accommodated in a carriage 18. Here, a plurality of ink cartridges 20 are provided for convenience, but it is not necessary to have a plurality. In such a state, the ink for ink jet recording is supplied from the ink cartridge 20 to the droplet discharge head 18 a mounted on the carriage 18. In FIG. 2, the discharge nozzle surface is in an invisible state because it faces downward, but ink jet recording ink is discharged from this discharge nozzle.
The droplet discharge head 18 a mounted on the carriage 18 is guided and moved by the guide shafts 21 and 22 by the timing belt 23 driven by the main scanning motor 26.
On the other hand, a specific coated paper (image support) is placed at a position facing the droplet discharge head 18 a by the platen 19. In FIG. 2, 1 is an ink jet recording apparatus, 2 is a main body housing,
Reference numeral 16 denotes a gear mechanism, 17 denotes a sub-scanning motor, and 25 and 27 denote gear mechanisms.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these Examples.

Examples 1-12, Comparative Examples 1-9
<Production of Black Pigment Dispersion A>
After premixing the materials of the following prescription, using a bead mill disperser (manufactured by Kotobuki Kogyo Co., Ltd., UAM-015), zirconia beads having a diameter of 0.03 mm (density 6.03 × 10 ⁻⁶ g / m ³ ) After dispersing for 15 minutes at a speed of 10 m / s and a liquid temperature of 30 ° C., coarse particles were centrifuged with a centrifuge (Model 3600, manufactured by Kubota Corporation) to prepare a black pigment dispersion A.
・ Carbon black (NIPEX150-IQ, manufactured by degussa, gas black)
・ ・ ・ 200 parts by weight ・ Naphthalenesulfonic acid sodium formalin condensate ... 50 parts by weight (Pionin A-45-PN, manufactured by Takemoto Yushi Co., Ltd., Naphthalenesulfonic acid dimer, trimer and tetramer total content (Amount = 30% by weight)
・ Distilled water: 750 parts by weight

<Production of Color Pigment Dispersion A>
After premixing 150 parts by weight of the following pigment, 40 parts by weight of the surfactant represented by the general formula (1) (m = 0, n = 40) and 810 parts by weight of distilled water, a disk-type bead mill (Shinmaru It was circulated and dispersed with Enterprises KDL type, media: zirconia balls having a diameter of 0.3 mm, to obtain a pigment dispersion.
-Magenta; C.I. I. Pigment Red 122 (manufactured by Dainippon Ink & Chemicals, FASTOGEN SUPER MAGENTA RG)
Cyan; C.I. I. Pigment Blue 15: 3 (Dainippon Seika Co., Ltd., Cyanine Blue A-292)
-Yellow; C.I. I. Pigment Yellow 74 (Dainippon Seika Co., Ltd., Yellow No. 43)

<Production of Color Pigment Dispersion B and Black Pigment Dispersion B>
(Adjustment Example 1) -Adjustment of magenta pigment dispersion B-
<Preparation of polymer solution A>
After sufficiently replacing the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer, and 0.4 g of mercaptoethanol were mixed and heated to 65 ° C.
Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxylethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, azobismethylvalero A mixed solution of 2.4 g of nitrile and 18 g of methyl ethyl ketone was dropped into the flask over 2.5 hours. After dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution A having a concentration of 50% by mass.

<Preparation of pigment dispersion>
After sufficiently stirring 28 g of polymer solution A, 42 g of magenta pigment (CI Pigment Red 122), 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of ion-exchanged water, It knead | mixed using the roll mill. The obtained paste was put into 200 g of pure water and stirred sufficiently, and then methyl ethyl ketone and water were distilled off using an evaporator, and this dispersion was further removed with polyvinylidene fluoride having an average pore size of 5.0 μm to remove coarse particles. A magenta pigment dispersion B containing 15% by mass of pigment and 20% by mass of solid was obtained by pressure filtration with a membrane filter. The volume average particle diameter of the obtained magenta pigment dispersion B of _{(D 50)} was 127nm was measured. The measurement of the volume average particle diameter _{(D 50)} particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) was used.

(Preparation Example 2) -Preparation of Cyan Pigment Dispersion B-
A cyan pigment dispersion B was prepared in the same manner as in Preparation Example 1, except that the magenta pigment in Preparation Example 1 was changed to a phthalocyanine pigment (CI Pigment Blue 15: 3).
The obtained cyan pigment dispersion B, the particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) volume average particle diameter _{(D 50)} measured in was 93 nm.

(Preparation Example 3) -Preparation of Yellow Pigment Dispersion B-
A yellow pigment dispersion B was prepared in the same manner as in Preparation Example 1, except that the magenta pigment in Preparation Example 1 was changed to a monoazo yellow pigment (CI Pigment Yellow 74).
The resulting yellow pigment dispersion B, the particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) volume average particle diameter _{(D 50)} measured in was 76 nm.

(Preparation Example 4) -Preparation of Black Pigment Dispersion B-
A black pigment dispersion B was prepared in the same manner as in Preparation Example 1, except that the magenta pigment in Preparation Example 1 was changed to carbon black (manufactured by Degussa, FW100).
The resulting black pigment dispersion B, the particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) volume average particle diameter _{(D 50)} measured in was 104 nm.

<Manufacture of ink>
The materials having the formulations shown in Tables 1 and 2 below were mixed and stirred for a total of 1 hour and 30 minutes, and then filtered through a membrane filter having a pore size of 0.8 μm to obtain inks of Examples and Comparative Examples.
The ink was prepared in the order of water-soluble organic solvent → surfactant → ion exchanged water, and after stirring for 30 minutes, pigment dispersions A and B, resin emulsion and neutralizing agent X were added and stirred for 1 hour. .

About each said ink, the characteristic was measured and evaluated as follows. The results are shown in Tables 1 and 2.
<Ink surface tension>
The surface tension (Wilhelmy method: 25 ° C.) of each ink was measured with a surface tension meter (CBVP-Z: manufactured by Kyowa Interface Science Co., Ltd.).

<Storage test>
Each ink was placed in a sealed container and stored at 70 ° C. for 14 days. The ink viscosity at 25 ° C. before and after storage was measured with an R-type viscometer (manufactured by Toki Sangyo Co., Ltd.) and evaluated according to the following criteria.
〔Evaluation criteria〕
A: Viscosity change rate before and after storage is less than 5% B: Viscosity change rate before and after storage is 5% or more and less than 10% C: Viscosity change rate before and after storage is 10% or more

<Image density>
Each ink is filled in an ink jet printer (IPSiO GX3000, manufactured by Ricoh Co., Ltd.), and a solid image is printed on My Recycled Paper GP paper (manufactured by NBS Ricoh Co., Ltd.) in a fast mode of plain paper in an environment of 25 ° C. and 50% RH. The color was measured with a densitometer X-Rite 938 (manufactured by X-Rite) and evaluated according to the following criteria.
[Black Evaluation Criteria]
A: Image density of 1.06 or more B: Image density of less than 1.06, 1.03 or more C: Image density of less than 1.03

[Color Evaluation Criteria]
A: Image density of 0.84 or more B: Image density of less than 0.84, 0.80 or more C: Image density of less than 0.80

The details of the materials indicated by the trade names in the above table are as follows.
FS-10: perfluoroalkyl sulfonic acid manufactured by Dupont FT-110: sodium perfluoroalkenyloxybenzene sulfonate manufactured by Neos EP-7025: polyoxyalkylene monoalkyl ether manufactured by Nippon Shokubai Co., Ltd. W5025 W5661: Mitsui Chemicals Polyurethane Co., Ltd. J-450: Johnson Polymer Co., Ltd.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Main body housing | casing 16 Gear mechanism 17 Subscanning motor 18 Carriage 18a Droplet discharge head 19 Platen 20 Ink cartridge 21 Guide shaft 22 Guide shaft 23 Timing belt 25 Gear mechanism 26 Main scanning motor 27 Gear mechanism 200 Ink cartridge 241 Ink bag 242 Inlet 243 Outlet 244 Ink cartridge case

JP 2003-335987 A

Claims (10)

  Contains a pigment dispersion, an anionic surfactant, a water-soluble organic solvent, a neutralizing agent X, and water, and the anionic surfactant has a 1% by weight aqueous solution with a pH of 2 to 3, and the carbon number of the alkyl group Is a perfluoroalkylsulfonic acid of 6. Ink for ink jet recording,   The inkjet according to claim 1, wherein the pigment dispersion is composed of a pigment dispersion A in which a pigment is dispersed with a surfactant and / or a pigment dispersion B in which the pigment is contained in a polymer. Recording ink.   The ink for inkjet recording according to claim 1 or 2, wherein the neutralizing agent X is 2-amino-2-ethyl-1,3-propanediol.   The ink for inkjet recording according to claim 2 or 3, wherein the pigment of the pigment dispersion A is carbon black and the surfactant is a sodium naphthalene sulfonate formalin condensate. The pigment of the pigment dispersion A is any one of a yellow pigment, a magenta pigment, and a cyan pigment, and the surfactant is a compound represented by the following general formula (1). The ink for inkjet recording as described.

(In the formula, R represents any of an alkyl group having 1 to 20 carbon atoms, an allyl group, and an aralkyl group. M represents an integer of 0 to 7, and n represents an integer of 20 to 80.)   The polymer of the pigment dispersion B has (a) a structural unit derived from a salt-forming group-containing monomer, or (a) a structural unit derived from a salt-forming group-containing monomer and (c) a structural unit derived from a hydrophobic monomer as a main chain. The ink for inkjet recording according to any one of claims 2 to 5, which is a graft polymer having (b) a structural unit derived from a macromer in a side chain.   An ink set for ink jet recording comprising the ink for ink jet recording according to claim 4 and the ink for ink jet recording according to claim 5.   An ink cartridge containing the ink for ink jet recording or the ink set for ink jet recording according to any one of claims 1 to 7 in a container.   An ink jet recording method comprising applying an stimulus to the ink for ink jet recording or the ink set for ink jet recording according to claim 1 and causing the ink to fly to form an image.   9. An ink jet recording apparatus comprising: the ink cartridge according to claim 8; and ink flying means for forming an image by applying a stimulus to the ink and causing the ink to fly.

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