JP2010059344A - Ink for inkjet recording and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ink for inkjet recording and an inkjet recording method using the ink reducing a curl amount of paper and exhibiting excellent continuous discharge properties. <P>SOLUTION: The ink for inkjet recording contains at least a color material, a water-soluble organic solvent, and water. The water-soluble organic solvent includes a polyoxypropylene glyceryl ether represented by formula (1), and alkyl alkanediol. In the formula, m, n, o, and p are integers of 0-24 and satisfy a relationship 4≤m+n+o+p≤24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording ink and an inkjet recording method using the same.

Water-based inkjet ink has advantages such as less bleeding, high image density, and less show-through when printing on plain paper. However, when there is a large amount of ink adhering to a photograph or drawing, the paper tends to curl. When the paper curls, it becomes difficult to convey the paper on the ink jet printer. If the paper is curled during high-speed printing or double-sided printing, paper conveyance is even more difficult. Therefore, an ink for ink jet recording is desired in which the curl of the paper is as small as possible with respect to the ink adhesion amount. The need for high-speed inkjet printers equipped with line heads is particularly high compared to serial printers.
As a known technique for suppressing paper curl, a method including a vinylpyrrolidone having a molecular weight of 80,000 to 250,000 and an acrylic acid copolymer (Patent Document 1), a colloidal silica having an average particle diameter of 5 to 100 nm, and a pigment are included. A method (Patent Document 2), a method of containing a metal oxide colloid and a water-soluble organic solvent having an SP value of 8 or more and less than 12 are known (Patent Document 3).
However, the conventional method merely suppresses the water in the ink from being absorbed by the paper, that is, the cellulose fiber, by adding some solid content.
In order to completely suppress curling, it is necessary to maintain hydrogen bonds between the cellulose molecules forming the cellulose fiber. When solids are added, ink solvents (alcohol, water, etc.) penetrate between the cellulose molecules. The swelling (= curl) of the cellulose fiber accompanying it cannot be suppressed sufficiently. Further, if the penetration of the ink solvent between cellulose molecules is sufficiently suppressed by adding a large amount of solid content, there is a problem that the continuous ejection property and the leaving ejection property are deteriorated.
On the other hand, Patent Document 4 discloses an ink-jet ink composition containing polyoxypropylene diglyceryl ether and 1,2-alkanediol, but it cannot prevent curling (see Comparative Example 05 described later). .

Japanese Patent Laid-Open No. 10-1629 JP-A-9-227812 JP 2006-321876 A JP 2004-155869 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink for ink jet recording that can reduce the curl amount of paper and is excellent in continuous discharge property, and an ink jet recording method using the same.

（式中、ｍ、ｎ、ｏ、ｐは各々、４≦ｍ＋ｎ＋ｏ＋ｐ≦２４を満たす０〜２４の整数である。）
２） 前記アルキルアルカンジオールが、炭素数３〜６のアルカンジオールを主鎖とし、炭素数１〜２のアルキルを分岐鎖とするものであることを特徴とする１）記載のインクジェット記録用インク。
３） 前記アルキルアルカンジオールが、２−メチル−１，３−プロパンジオール、３−メチル−１，３−ブタンジオール、３−メチル−１，５−ペンタンジオール、２−エチル−１，３−へキサンジオールから選ばれた少なくとも一種であることを特徴とする２）記載のインクジェット記録用インク。
４） 前記色材が、ポリマー微粒子中に水不溶性又は水難溶性の色材を含有させたポリマーエマルジョンとして含まれていることを特徴とする１）〜３）の何れかに記載のインクジェット記録用インク。
５） ラインヘッド印字装置において、１）〜４）の何れかに記載のインクジェット記録用インクを使用することを特徴とするインクジェット記録方法。 The above problems are solved by the following inventions 1) to 5).
1) An ink jet recording comprising at least a coloring material, a water-soluble organic solvent, and water, wherein the water-soluble organic solvent contains a polyoxypropylene diglyceryl ether of the following formula (1) and an alkylalkanediol. For ink.

(In the formula, m, n, o, and p are each an integer of 0 to 24 that satisfies 4 ≦ m + n + o + p ≦ 24.)
2) The ink for ink jet recording according to 1), wherein the alkylalkanediol has an alkanediol having 3 to 6 carbon atoms as a main chain and an alkyl having 1 to 2 carbon atoms as a branched chain.
3) The alkylalkanediol is converted into 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3- The ink for inkjet recording according to 2), which is at least one selected from xylenediol.
4) The ink for ink-jet recording according to any one of 1) to 3), wherein the color material is contained as a polymer emulsion in which a water-insoluble or hardly water-soluble color material is contained in polymer fine particles. .
5) A line head printer, wherein the ink for ink jet recording according to any one of 1) to 4) is used.

Hereinafter, the present invention will be described in detail.
The present invention is characterized in that polyoxypropylene diglyceryl ether (POP-DG) and alkylalkanediol (AAD) of the above formula (1) are used as the water-soluble organic solvent, thereby enabling high image quality and high ejection reliability. Thus, a low curl ink for ink jet recording can be obtained. This is because the water-soluble organic solvent hardly breaks hydrogen bonds between cellulose molecules even if it penetrates between cellulose molecules.
This will be explained in more detail. POP-DG and AAD are more lipophilic than the conventional water-soluble organic solvents (glycerin, butanediol, etc.), and are rich in lipophilic groups. Since the ratio of the hydroxyl group, which is a hydrophilic group capable of hydrogen bonding, is small, even if it penetrates between cellulose molecules, it is difficult to break hydrogen bonds between cellulose molecules. In short, this model is “low attack against hydrogen bonds between cellulose molecules”.
In addition, since POP-DG and AAD have low surface tension, they penetrate in advance between the cellulose molecules, and the hydroxyl groups of POP-DG or AAD are hydrogenated to the hydroxyl groups of the cellulose molecules as shown in (γ) of FIG. It binds and stays in the cellulose molecule part, the lipophilic group part of POP-DG or AAD covers the hydrogen bond of the cellulose molecule, inhibits the contact of water which is a volatile hydrophilic group rich solvent, and between the cellulose molecules It makes it difficult to break hydrogen bonds. In short, this model is “the hydrogen bond coverage of cellulose molecules”.
In addition, since it is a liquid called POP-DG or AAD that covers the hydrogen bonds of cellulose molecules and inhibits contact with an aqueous continuous phase (alcohol, water, etc.), even if water volatilizes. Precipitation, solidification, and fluidity are unlikely to occur. That is, the continuous discharge property and the undischarging property of the ink are maintained.

Here, the difference in the action of water-soluble organic substances having water and hydroxyl groups between cellulose molecules will be described with reference to FIG.
FIG. 1A is a schematic diagram of an elementary fibril. Plant fibers have a filamentous structure called fibrils, fibrils are further composed of microfibrils having a diameter of several nm to 20 nm and lengths of 1 μm to several μm, and microfibrils are further composed of several to several tens of elementary fibrils.
FIG.1 (b) is a schematic diagram of a cellulose molecule. Elementary fibrils consist of dozens of cellulose molecules arranged in parallel. At this time, a strong hydrogen bond is formed between adjacent cellulose molecules, and a bundle having a diameter of about 3 to 4 nm is formed.
FIG.1 (c) is a figure which shows the aspect ((alpha)) ((beta)) ((gamma)) of the hydrogen bond produced between two cellulose molecules. A dotted line represents a hydrogen bond and R represents a lipophilic group of POP-DG or AAD.
The hydrogen bond (α) indicates a normal hydrogen bond state between cellulose molecules.
The hydrogen bond (β) indicates a state in which water molecules are interposed in hydrogen bonds between cellulose molecules, and the position of hydrogen bonds is changed by evaporation of the water. To further explain this phenomenon, when water infiltrates into the paper and the bond between celluloses is broken as shown in the figure, the fibers loosen and extend. Here, when water disappears from the site by drying and movement, the fibers shrink and the broken hydrogen bonds recombine. However, no pressure is applied as the paper is applied during papermaking, and during this drying process the fibers are hydrogen bonded in a free and loose position, resulting in a different paper shape or curl.
The hydrogen bond (γ) indicates a state in which a hydroxyl group of POP-DG or AAD is interposed with respect to a hydroxyl group not involved in cellulose hydrogen bond, and further prevents water molecules from entering between cellulose molecules.

Further, if the AAD has a main chain of alkanediol having 3 to 6 carbon atoms and a branched chain of alkyl having 1 to 2 carbon atoms, the balance between the hydrophilic group and the lipophilic group is water-soluble and the lipophilic group. It becomes richer and the above-mentioned “low aggressiveness to hydrogen bonding between cellulose molecules” and “covering ability of hydrogen bonding of cellulose molecules” model is expressed better. Of these, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, and 2-ethyl-1,3-hexanediol are preferred. is there.
The total amount of POP-DG and AAD is 10 to 50% by weight of the total ink, preferably 20 to 50% by weight, and more preferably 40 to 50% by weight. Within this range, “high image quality, high ejection reliability, and low curl” can be achieved.

The ink for ink jet recording of the present invention contains a coloring material, a water-soluble organic solvent (POP-DG and PPD), water, and various materials (surfactant, surfactant, Resin emulsion, pH adjuster, antiseptic / antifungal agent, rust preventive agent, etc.).
As the coloring material, for example, a pigment or a dye can be used, and it is particularly preferable that the coloring material is contained as a polymer emulsion in which a water-insoluble or poorly water-soluble coloring material is contained in the polymer fine particles. That is, in the present invention, since POP-DG and AAD are used as the water-soluble organic solvent as described above, the permeability of the ink is increased and the permeability of the coloring material into the paper is also increased. As a result, the amount of color material remaining on the paper surface is reduced and the print image density is lowered. As a countermeasure against this, it is preferable to use a color material obtained by adding a water-insoluble or poorly water-soluble color material to polymer fine particles to form a polymer emulsion. This color material easily aggregates due to absorption of the dispersion medium on the paper, so-called vehicle, and the amount of the color material remaining on the paper surface can be increased, so that the print image density can be maintained.

Furthermore, in order to more efficiently leave a polymer emulsion containing a water-insoluble or poorly water-soluble coloring material in polymer fine particles on the paper surface and accelerate the aggregation due to the absorption of the vehicle into the paper, the ink has excessive permeability. In addition, it is desirable to increase the content of the polymer emulsion, and as a result, the ink viscosity at 25 ° C. is desirably 4 mPa · sec or more.
Furthermore, in order to more efficiently leave the polymer emulsion containing the water-insoluble or poorly water-soluble coloring material in the polymer fine particles on the paper surface, the permeability of the dispersion medium of the polymer emulsion, so-called vehicle, to paper is further increased. It is desirable to increase the separation property of the polymer emulsion / vehicle on paper, and for this purpose, it is desirable to add an anionic or nonionic surfactant in order to decrease the surface tension of the vehicle.

The state of the color material in the polymer emulsion may be either a state in which the color material is sealed in the polymer fine particles or a state in which the color material is adsorbed on the surface of the polymer fine particles, or both may coexist. Further, it is not necessary that all the coloring material is encapsulated or adsorbed in the polymer fine particles, and the coloring material may be dispersed in the emulsion as long as the effects of the present invention are not impaired.
The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be encapsulated or adsorbed by a polymer. Here, water-insoluble or poorly water-soluble means that it does not dissolve 10 parts by weight or more with respect to 100 parts by weight of water at 20 ° C. When dissolved, the separation or sedimentation of the coloring material is visually observed on the aqueous solution surface layer or lower layer. It means not being able to.
Examples thereof include dyes such as oil-soluble dyes and disperse dyes, pigments, and the like. Oil-soluble dyes and disperse dyes are preferable from the viewpoint of good adsorption and encapsulation, but pigments are preferably used from the light resistance of the obtained image.

Examples of pigments that can be used in the present invention include organic pigments and inorganic pigments. For example, for black and white, carbon blacks such as furnace black, lamp black, acetylene black, and channel black (CI pigment black) are used. 7), or metal pigments such as copper oxide, iron oxide (CI pigment black 11), titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color use, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 81, 83 (Disazo Yellow HR) ), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 153, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 [Permanent Red B (Ba)], 48: 2 [Permanent Red 2B (Ca)], 48 : 3 [permanent red 2B (Sr)], 48: 4 [permanent red 2B (Mn)], 49: 1, 52: 2, 53: 1, 57: 1 (brilliant carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, C I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19 (quinacridone red), 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 127 (bitumen ), 28 (cobalt blue), 29 (ultraviolet), 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc., but is not limited thereto.

The blending amount of the coloring material is preferably about 10 to 200% by weight, particularly about 25 to 150% by weight, based on the weight of the polymer.
As the polymer that forms the polymer emulsion, for example, vinyl polymers, polyester polymers, polyurethane polymers, and the like can be used. Particularly preferred are vinyl polymers and polyester polymers, such as those disclosed in JP-A Nos. 2000-53897 and 2001-139849.
The average particle size of the polymer fine particles containing a colorant is most preferably 0.16 μm or less in the ink. The content of the polymer fine particles in the ink is preferably about 8 to 20% by weight, more preferably about 8 to 12% by weight in terms of solid content.

As the water-soluble organic solvent, in addition to the above POP-DG and AAD, another water-soluble organic solvent may be used in combination, and examples thereof include the following.
Glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane, ethylene glycol, 1,3 -Propanediol, 1,4-butanediol, 2,3-butanediol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,2,6-hexanetriol, 1,2,4 -Hydroxy compounds such as butanetriol, 1,2,3-butanetriol, thiodiglycol, pentaerythritol;
Polyhydric alcohol alkyl ethers such as 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 monoethyl ether;
Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;
Nitrogen-containing heterocyclic compounds (lactams) such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;
Amides such as formamide, N-methylformamide, N, N-dimethylformamide;
Amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine;
Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol;
Propylene carbonate, ethylene carbonate

As the surfactant, various types such as an anionic type, a cationic type, a fluorine type, and an acetylene glycol type can be mentioned, and these can be used alone or in combination of two or more.
Anionic surfactants include higher fatty acid salts, higher alkyl dicarboxylates, higher alcohol sulfates, higher alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, and naphthalene sulfonate salts (Na, K). , Li, Ca), formalin polycondensate, higher fatty acid and amino acid condensate, dialkylsulfosuccinate, alkylsulfosuccinate, naphthenate, alkyl ether carboxylate, acylated peptide, α-olefin sulfonic acid Salt, N-acylmethyl taurine, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkyl phenyl ether sulfate, monoglyculate, alkyl ether phosphate ester, alkyl phosphate ester salt, etc. It is below.

  Nonionic surfactants include silicone, acrylic acid copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, Ethylene oxide derivatives of alkylphenol formalin condensate, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene compound fatty acid ester type, polyethylene oxide condensed polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin Fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester Le, fatty acid alkanolamides, polyoxyethylene fatty acid amides.

Fluorosurfactants include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds, etc. Can be mentioned.
Further, commercially available fluorine compounds include Surflon S-111, S-112, S-113, S121, S131, S132, S-141 and S-145 (manufactured by Asahi Glass Co., Ltd.), Fullrad FC- 93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (manufactured by Sumitomo 3M) and the like can be easily obtained and used in the present invention. In particular, when FT-110, 250, 251, 400S manufactured by Neos Co., Ltd. is used, good print quality is obtained and the color developability is remarkably improved.
Examples of acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5- Examples include dimethyl-1-hexyn-3-ol.
As for acetylene glycol surfactants, commercially available products such as Surfynol 104, 82, 465, 485 or TG from Air Products (USA) can be easily obtained and used in the present invention. In particular, when Surfynol 465 is used, good print quality is obtained, and the permeability of the vehicle to paper is significantly improved.

A resin emulsion is an emulsion in which the continuous phase is water and the dispersed phase is the resin component, and has the property of thickening and agglomerating, suppressing the penetration of colored components, and further promoting the fixing to recording materials. Have Further, depending on the type of resin emulsion, a film is formed on the recording material, and the printed material has an effect of improving the abrasion resistance.
Examples of the resin component in the dispersed phase include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins. As the resin, a polymer having both a hydrophilic part and a hydrophobic part is preferable. The particle size of these resin components is not particularly limited as long as an emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 to 100 nm.

These resin emulsions can be obtained by mixing resin particles in water together with a surfactant as necessary. For example, an acrylic resin or styrene-acrylic resin emulsion can be obtained by adding (meth) acrylic acid ester or styrene, (meth) acrylic acid ester, and optionally (meth) acrylic acid ester, and a surfactant to water. It can be obtained by mixing.
The mixing ratio of the resin component and the surfactant is usually preferably about 10: 1 to 5: 1. If the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and if it exceeds the above range, the water resistance of the ink tends to be lowered or the penetrability tends to deteriorate.
The ratio of the resin to water in the resin emulsion is suitably 60 to 400 parts by weight, preferably 100 to 200 parts by weight with respect to 100 parts by weight of the resin.
Examples of commercially available resin emulsions include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 ( Styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon), Cybinol SK-200 (acrylic resin emulsion, manufactured by Seiden Chemical), etc. Can be mentioned.

As the pH adjuster, any substance can be used as long as the pH can be adjusted to 7 or more without adversely affecting the ink to be prepared. 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, and quaternary phosphonium. Examples thereof include carbonates of alkali metals such as hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.
Examples of antiseptic / antifungal agents include sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, 1,2-benzisothiazolin-3-one and the like.
Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and benzotriazole.
Furthermore, a metal ion sealing agent, a water-soluble ultraviolet absorber, a water-soluble infrared absorber, or the like may be added depending on the purpose.
The ink-jet ink of the present invention is very suitably used in a line head printer. This is because, in a line head printing apparatus, printing is often performed at high speed, and curling and deformation of paper are items that should be avoided in order to feed and discharge paper as a printing medium at high speed. .

  According to the present invention, it is possible to provide an ink for ink jet recording which can reduce the curl amount of paper and which is excellent in continuous discharge property, and an ink jet recording method using the same.

  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 to 13 and Comparative Examples 01 to 07
Inkjet recording inks of Examples and Comparative Examples were prepared and evaluated as follows. The ink components are the following (i) to (viii), and the blending ratio (wt%) of each component is as shown in Tables 1 to 7. Table 1 shows examples using colorant-containing polymer emulsions, and Table 2 shows examples using self-dispersing pigments. Table 3 shows a comparative example with Example 5 that does not include one or both of POP-DG and AAD. Tables 4 and 5 show examples and comparative examples in which “m + n + o + p” of POP-DG was changed. Table 6 shows an example in which the type of AAD is changed. Table 7 shows a comparative example using a water-soluble organic solvent other than AAD.
(I) Polymer emulsion in which water-insoluble or poorly water-soluble colorant is contained in polymer fine particles (ii) Anionic or nonionic surfactant (iii) Water-soluble organic solvent: POP-DG of the formula (1)
(Iv) Water-soluble organic solvent: AAD (2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3 -Hexanediol)
(V) pure water (vi) pH adjuster (vii) preservative (viii) rust inhibitor

<Ink preparation method>
First, the polymer emulsion (i) was prepared as follows.
(A) Preparation of phthalocyanine pigment-containing polymer fine particle dispersion: Preparation Example 3 of JP-A No. 2001-139849 was reexamined to obtain a blue polymer fine particle dispersion. The average particle diameter (D50%) of the fine polymer particles measured by Microtrac UPA was 93 nm.
(B) Preparation of dimethylquinacridone pigment-containing polymer fine particle dispersion: A red-purple polymer fine particle dispersion was obtained in the same manner as in (a) except that the phthalocyanine pigment in (a) was changed to Pigment Red 122. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 127 nm.
(C) Preparation of monoazo yellow pigment-containing polymer fine particle dispersion: A yellow polymer fine particle dispersion was obtained in the same manner as in (a) except that the phthalocyanine pigment in (a) was changed to Pigment Yellow 74. The average particle diameter (D50%) of the polymer fine particles measured by Microtrac UPA was 76 nm.
(D) Preparation of carbon black-containing fine polymer particle dispersion: A black fine polymer particle dispersion was obtained in the same manner as in (a) except that the phthalocyanine pigment in (a) was changed to carbon black (Degussa FW100). It was. The average particle size (D50%) of the polymer fine particles measured by Microtrac UPA was 104 nm.
Subsequently, the polymer emulsion, an anionic or nonionic surfactant, a water-soluble organic solvent, and pure water were mixed and dispersed and stirred with a dissolver (DISPERMAT-FE) to prepare a pigment dispersion.
Subsequently, a pH adjuster, an antiseptic, and an antirust agent were added, mixed and stirred, and then filtered through a 3 μm filter to obtain an ink jet recording ink.

The ink jet recording ink was evaluated for viscosity, image density, continuous ejection property, and curl amount.
<Viscosity evaluation method>
Evaluation was performed by the following apparatus and conditions.
Viscometer: manufactured by A & D, tuning-fork type vibration viscometer, SV-10
-Measurement conditions: 23 ° C

<Image density evaluation method>
The image density after monochrome solid printing was evaluated by the following apparatus and conditions.
・ Printer name: Prototype line head printer (see Fig. 2)
・ Media name: TYPE6200 PPC paper manufactured by Ricoh Co., Ltd. ・ Printing conditions: recording density 300 × 600 dpi, 100% duty, Mj21pl,
23 ° C / 65% RH
X-Rite, portable spectral density, X-Rite 939

<Evaluation method of continuous discharge>
The dot diameter change rate (%) after printing 1000 sheets was evaluated by the following apparatus and conditions.
・ Printer name: Prototype line head printer (see Fig. 2)
・ Media name: TYPE6200 PPC paper manufactured by Ricoh Co., Ltd. ・ Printing conditions: recording density 300 × 600 dpi, 100% duty, Mj21pl,
23 ° C / 65% RH
The evaluation criteria were as follows.
5: Less than 5%
4: 5, 5% or more and less than 10%
3: 10% or more and less than 15%
2: 15% or more and less than 20%
1: 2, over 20%

<Evaluation method of curl amount>
Using the following apparatus and conditions, a solid color was printed within 3 mm from the edge of the paper, and after standing for 1 hour on the printing surface, the curl height at the four corners of the paper was evaluated.
・ Printer name: Prototype line head printer (see Fig. 2)
・ Media name: TYPE6200 PPC paper manufactured by Ricoh Co., Ltd. ・ Printing conditions: recording density 300 × 600 dpi, 100% duty, Mj21pl,
23 ° C / 65% RH
The evaluation criteria were as follows.
5: Less than 3mm
4: 3 to less than 6mm
3: 6 to less than 9mm
2: 9 or more and less than 12mm
1: 12mm or more

Here, the apparatus of FIG. 2 will be described.
FIG. 2 is a schematic diagram showing the internal structure of the prototype line head printer used for the evaluation.
In the image recording apparatus A, the paper feed tray 1 has a configuration in which a pressure plate 2 and a paper feed rotating body 4 for feeding recording paper 3 are attached to a base 5. The pressure plate 2 can rotate around a rotation axis a attached to the base 5, and is urged by the pressure plate spring 6 to the sheet feeding rotator 4.
A separation pad (not shown) made of a material having a large friction coefficient, such as an artificial skin, is provided at a portion of the pressure plate 2 facing the sheet feeding rotator 4 in order to prevent double feeding of the recording paper 3. . Further, a release cam (not shown) for releasing the contact between the pressure plate 2 and the sheet feeding rotating body 4 is provided.
In the above configuration, the release cam pushes the pressure plate 2 down to a predetermined position in the standby state. As a result, the contact between the pressure plate 2 and the sheet feeding rotating body 4 is released. In this state, when the driving force from the transport roller 7 is transmitted to the sheet feeding rotator 4 and the release cam by a gear or the like, the release cam moves away from the pressure plate 2 and the pressure plate 2 rises, and the sheet feeding rotator 4 and the recording are recorded. The paper 3 comes into contact.
Then, the recording paper 3 is picked up and started to be fed along with the rotation of the paper feed rotating body 4 and separated one by one by a separation claw (not shown). The sheet feeding rotator 4 rotates to feed the recording sheet 3 to the platen 10 via the conveyance guides 8 and 9.
The recording paper 3 passes between the conveyance guides 8 and 9 and is guided to the conveyance roller 7, and is conveyed to the platen 10 by the conveyance roller 7 and the pinch roller 11. After that, the contact state between the recording paper 3 and the paper feed rotating body 4 is released again, and the driving force from the transport roller 7 is cut off.
The paper feed rotator 12 for manual paper feed feeds the recording paper 3 mounted on the manual feed tray 13 in accordance with the recording command signal of the computer and transports it to the transport roller 7.
The recording paper 3 conveyed to the platen 10 passes under the line head 14. Here, the recording paper conveyance speed and the droplet discharge timing are adjusted based on a signal controlled by an electric circuit (not shown), thereby forming a desired image.

The evaluation results are summarized in Tables 1 to 7. The meanings of the abbreviations in the table are as follows.
C = cyan, m = magenta, y = yellow, k = black. PB15: 4 = C. I. Pigment Blue 15: 4 (phthalocyanine blue)
DQ122 = C. I. Pigment Red 122 (dimethyl quinacridone)
MA74 = C. I. Pigment Yellow 74 (monoazo)
・ Acid CB = Acidic carbon black
FSAA: Fluorosurfactant (FT-110 manufactured by Neos Co., Ltd.)
AG: Acetylene glycol surfactant (Surfinol 465 manufactured by Air Products)
・ 1,3-BD = 1,3-butanediol ・ POP-DG: polyoxypropylene diglyceryl ether ・ MPD: 2-methyl-1,3-propanediol,
MBD: 3-methyl-1,3-butanediol,
MPeD: 3-methyl-1,5-pentanediol,
EHD: 2-ethyl-1,3-hexanediol,
• PeD: 1,5-pentanediol • HD: 1,6-hexanediol • TEA: triethanolamine • BIT: 1,2-benzisothiazolin-3-one • BTA: benzotriazole • 1,2-BD: 1,2-butanediol In addition, as PB15: 4, CAB-O-JET250: manufactured by Cabot Corporation, an average particle size: 0.091 μm self-dispersion pigment, and as DQ122, CAB-O-JET260: Cabot Corporation The self-dispersing pigment having an average particle size of 0.105 μm manufactured by CAB-O-JET270: manufactured by Cabot Corporation as the MA74, the self-dispersing pigment having an average particle size of 0.137 μm by the CAB -O-JET300: Self-dispersed pigments having an average particle size of 0.130 μm manufactured by Cabot Corporation were used.

From Table 3 above, it can be seen that in Comparative Examples 01 to 02 that do not include one or both of POP-DG and AAD, the curl amount may become the evaluation stage 2 or less.
From Table 4 to Table 5 above, in the range of m + n + o + p = 9-18 (however, Example 5 where m + n + o + p = 9 is shown in Table 3), both the continuous ejection performance and the curl amount satisfy the evaluation stages 4-5. It can be seen that better results are obtained compared to 7 (m + n + o + p = 4) and Example 10 (m + n + o + p = 24). On the other hand, in Comparative Example 03 (m + n + o + p = 3), the curl amount is in the evaluation stage 2, and in Comparative Example 04 (m + n + o + p = 30), the evaluation stage of the curl amount is 5, but the evaluation stage of continuous discharge property is It turns out that it will be 2.
From Table 7 above, it can be seen that both include the case where the curl amount evaluation stage is 2 or less.

The figure explaining the difference in action of the water-insoluble organic substance which has water and a hydroxyl group between cellulose molecules. (A) Schematic diagram of elementary fibrils, (b) Schematic diagram of cellulose molecules, (c) Diagram showing hydrogen bonds (α) (β) (γ) generated between two cellulose molecules. The figure which shows the prototype line head printer used for the continuous discharge property evaluation of this invention.

Explanation of symbols

A Image recording apparatus a Rotating shaft 1 Paper feed tray 2 Pressure plate 3 Recording paper 4 Paper feed rotator 5 Base 6 Pressure plate spring 7 Transport roller 8 Transport guide 9 Transport guide 10 Platen 11 Pinch roller 12 Paper feed rotator for manual feed 13 Bypass tray 14 Line head

Claims (5)

An ink for ink jet recording, comprising at least a coloring material, a water-soluble organic solvent, and water, the polyoxypropylene diglyceryl ether represented by the following formula (1) and an alkylalkanediol as the water-soluble organic solvent: .

(In the formula, m, n, o, and p are each an integer of 0 to 24 that satisfies 4 ≦ m + n + o + p ≦ 24.)   2. The ink for ink jet recording according to claim 1, wherein the alkylalkanediol has an alkanediol having 3 to 6 carbon atoms as a main chain and an alkyl having 1 to 2 carbon atoms as a branched chain.   The alkylalkanediol is 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol. The ink for inkjet recording according to claim 2, wherein the ink is at least one selected from the group consisting of:   The ink for inkjet recording according to any one of claims 1 to 3, wherein the coloring material is contained as a polymer emulsion in which a water-insoluble or poorly water-soluble coloring material is contained in polymer fine particles.   An ink jet recording method using the ink for ink jet recording according to claim 1 in a line head printer.

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