JP2022131136A - Aqueous inkjet ink composition, inkjet recording device, and inkjet recording method - Google Patents

Abstract

To provide an aqueous inkjet ink composition that is used in an inkjet recording device provided with an ink storage having an openable/closable inlet for ink injection and prevents air bubbles from forming therein and also prevents the formation of aggregate, and allows for the formation of an image with excellent color development.SOLUTION: An aqueous inkjet ink composition contains a colorant, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound with an HLB value of 15 or less. The aqueous inkjet ink composition is charged into an inkjet recording device provided with an ink storage having an openable/closable inlet for ink injection.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a water-based inkjet ink composition, an inkjet recording apparatus, and an inkjet recording method.

Since the inkjet method can form a high-quality image on a recording medium, various techniques have been developed in the past. Development of recording apparatuses using the ink jet method is also active. In addition, extensive studies have been made on optimizing the ink composition according to the configuration of each device that has been developed.

For example, Japanese Patent Application Laid-Open No. 2002-200000 discloses an ink supply system provided for each water-based ink, and the ink supply system includes a tube made of a resin material that supplies the water-based ink, and a serial print head. It is disclosed that the surface tension of the water-based ink to be used is set to a value within a specific range when using an inkjet recording apparatus. The document describes that by doing so, bleeding of an image can be suppressed even when the recording apparatus is used, and good ejection stability can be obtained even when the ink is ejected over a long period of time. be. Thus, there is also a demand for development of an ink composition having performance suitable for the configuration of an inkjet recording apparatus.

JP 2017-081151 A

In an inkjet recording apparatus having an ink container having an openable and closable ink inlet, air bubbles are likely to be generated in the ink container when a user fills the ink container with a water-based inkjet ink composition. If air bubbles are generated, there is a risk that the ejection stability of water-based ink jet ejection from the recording head will decrease, or that an ink remaining amount sensor will be misdetected if it is provided. In order to suppress such air bubbles, for example, it is possible to suppress the generation of air bubbles by blending a compound having an HLB value of 15 or less in the water-based inkjet ink composition. Although it can suppress the generation of air bubbles, it has the effect of destabilizing the dispersed state of the dispersing components such as the coloring material and resin particles, and aggregates may be generated in the water-based inkjet ink composition.

In addition, in an inkjet recording apparatus having an ink container having an openable and closable ink inlet, the water-based inkjet ink composition dries easily from the ink inlet, and water evaporates before the organic solvent. ratio tends to be high. Therefore, at least one of the evaporation of water and the concentration of the organic solvent causes aggregates to form in the water-based inkjet ink composition.

Therefore, even when used in an inkjet recording apparatus having an ink container having an ink inlet that can be opened and closed, it is possible to suppress the generation of air bubbles and the generation of aggregates while maintaining good image quality. There is a need for water-based inkjet ink compositions.

One aspect of the water-based inkjet ink composition according to the present invention is
Containing a coloring material, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound having an HLB value of 15 or less,
It is used by being filled in an ink jet recording apparatus having an ink containing body having an openable and closable ink inlet.

One aspect of the inkjet recording apparatus according to the present invention is
the water-based inkjet ink composition described above;
an ink containing body containing the water-based inkjet ink composition;
a recording head that ejects the water-based inkjet ink composition;
An inkjet recording device comprising
The ink container has an openable and closable ink inlet for filling the water-based inkjet ink composition.

One aspect of the inkjet recording method according to the present invention is
It includes ejecting the water-based inkjet ink composition described above from a recording head and attaching it to a recording medium.

1 is a perspective view schematically showing the schematic configuration of a first embodiment of a printing apparatus in a see-through state; FIG. FIG. 2 is a perspective view showing an ink supply unit provided inside the housing of the printing apparatus; 2 is a plan view of the ink supply unit; FIG. FIG. 4 is a partially broken cross-sectional view taken along line 4-4 in FIG. 3; 4 is a partially broken cross-sectional view taken along line 5-5 in FIG. 3; FIG. 4 is a perspective view of the ink container with the cap removed; FIG. FIG. 2 is a side view of an ink container; FIG. 2 is a front view of an ink container; FIG. 2 is a plan view of an ink container; 10-10 line arrow sectional view in FIG. 11-11 line arrow sectional view in FIG. FIG. 4 is a partially cutaway front view showing a state immediately before an ink supply operation to the ink containing body; FIG. 4 is a partially cutaway side view showing a state immediately before an ink supply operation to the ink containing body; FIG. 4 is a partially cutaway front view showing a state in which ink is being replenished to the ink container. FIG. 4 is a partially broken side view showing a state in which an ink container is being replenished with ink; FIG. 4 is a partially cutaway front view showing a state in which the positioning portion of the ink container is in contact with the receiving surface of the ink container during ink replenishment; FIG. 4 is a partially cutaway side view showing a state in which the positioning portion of the ink container is in contact with the receiving surface of the ink container during ink replenishment;

Embodiments of the present invention are described below. The embodiments described below illustrate examples of the invention. The present invention is by no means limited to the following embodiments, and includes various modifications implemented within the scope of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

As used herein, "(meth)acryl" represents acrylic or methacrylic, and "(meth)acrylate" represents acrylate or methacrylate.

1. Water-Based Inkjet Ink Composition The water-based inkjet ink composition of the present embodiment contains a colorant, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound having an HLB value of 15 or less. Since there are a wide variety of compounds with an HLB value of 15 or less, the components that are essential or optionally contained in the water-based inkjet ink composition will be described first, and then the compounds with an HLB value of 15 or less will be described.

1.1. Colorant The water-based inkjet ink composition contains a colorant. Examples of coloring materials include water-soluble dyes, disperse dyes, and pigments, and any of these may be used, or a mixture thereof may be used. However, the water-based inkjet ink composition preferably contains a pigment, and when it contains only the pigment, it exhibits a more pronounced effect.

1.1.1. Water-Soluble Dye The water-based inkjet ink composition of the present embodiment may contain one or more water-soluble dyes selected from acid dyes, reactive dyes and direct dyes. Also, the hue of the water-soluble dye is not limited, and may be so-called process colors such as cyan, magenta, yellow, and black, or so-called special colors such as blue, red, orange, and fluorescent colors. Further, water-soluble dyes can dye recording media such as fabrics (fibers), but the dyeing mechanism is not particularly limited. Furthermore, these may be used individually by 1 type, and may use 2 or more types together.

Specific examples of acid dyes include:
C. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 19, 24, 26, 27, 28, 32, 35, 37, 42, 51, 52, 57, 62, 75, 77, 80, 82, 83, 85, 87, 88, 89, 92, 94, 95, 97, 106, 111, 114, 115, 117, 118, 119, 127, 128, 129, 130, 131, 133, 134, 138, 143, 145, 149, 151, 154, 155, 158, 168, 180, 183, 184, 186, 194, 198, 199, 209, 211, 215, 216, 217, 219, 249, 252, 254, 256, 257, 260, 261, 262, 263, 265, 266, 274, 276, 282, 283, 289, 299, 301, 303, 305, 315, 318, 320, 321, 322, 336, 337, 361, 396, 397 ;
C. I. Acid Violet 5, 7, 11, 15, 31, 34, 35, 41, 43, 47, 48, 49, 51, 54, 66, 68, 75, 78, 90, 97, 103, 106, 126, etc.;
C. I. Acid Yellow 1, 3, 7, 11, 17, 19, 23, 25, 29, 36, 38, 39, 40, 42, 44, 49, 50, 59, 61, 64, 70, 72, 75, 76, 78, 79, 98, 99, 110, 111, 112, 114, 116, 118, 119, 127, 128, 131, 135, 141, 142, 143, 151, 159, 161, 162, 163, 164, 165, 169, 174, 184, 190, 195, 196, 197, 199, 207, 218, 219, 222, 227, 246, etc.;
C. I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 49, 54, 59, 60, 62, 72, 74, 76, 78, 80, 82, 83, 87, 90, 92, 93, 100, 102, 103, 104, 106, 112, 113, 114, 117, 120, 126, 127, 127: 1, 128, 129, 130, 131, 133, 138, 140, 142, 143, 151, 154, 156, 158, 161, 166, 167, 168, 170, 171, 175, 181, 182, 183, 184, 185, 187, 192, 193, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 232, 239, 247, 249, 258, 260, 264, 271, 277, 277: 1, 278, 279, 280, 284, 288, 290, 296, 298, 300, 317, 324, 326, 333, 335, 338, 342, 350, etc.;
C. I. Acid Black 1, 2, 7, 24, 26, 29, 31, 44, 48, 50, 51, 52, 52: 1, 58, 60, 62, 63, 64, 67, 72, 76, 77, 94, 107, 108, 109, 110, 112, 115, 118, 119, 121, 122, 131, 132, 139, 140, 155, 156, 157, 158, 159, 172, 191, 194, 234, etc.;
C. I. Acid Orange 1, 7, 8, 10, 19, 20, 24, 28, 33, 41, 43, 45, 51, 56, 63, 64, 65, 67, 74, 80, 82, 85, 86, 87, 88, 94, 95, 122, 123, 124, etc.;
C. I. Acid Green 3, 7, 9, 12, 16, 19, 20, 25, 27, 28, 35, 36, 40, 41, 43, 44, 48, 56, 57, 60, 61, 65, 73, 75, 76, 78, 79, etc.;
C. I. Acid Brown 2, 4, 13, 14, 19, 20, 27, 28, 30, 31, 39, 44, 45, 46, 48, 53, 100, 101, 103, 104, 106, 160, 161, 165, 188, 224, 225, 226, 231, 232, 236, 247, 256, 257, 266, 268, 276, 277, 282, 289, 294, 295, 296, 297, 298, 299, 300, 301, 302, etc. is mentioned.

Specific examples of direct dyes include:
C. I. Direct Red 2, 4, 9, 23, 26, 31, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 89, 92, 95, 111, 173, 184, 207, 211, 212, 214, 218, 221, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243, 247, etc.;
C. I. Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100, 101, etc.;
C. I. Direct Yellow 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53, 58, 59, 68, 86, 87, 93, 95, 96, 98, 100, 106, 108, 109, 110, 130, 132, 142, 144, 161, 163, etc.;
C. I. Direct Blue 1, 10, 15, 22, 25, 41, 55, 67, 68, 71, 76, 77, 78, 80, 84, 86, 87, 90, 98, 106, 108, 109, 120, 151, 156, 158, 159, 160, 153, 168, 189, 192, 193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 226, 229, 236, 237, 244, 248, 249, 251, 252, 264, 270, 280, 288, 289, 291 etc.;
C. I. Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97, 108, 112, 113, 114, 117, 118, 121, 122, 125, 132, 146, 154, 166, 168, 173, 195, 199 and the like.

Specific examples of reactive dyes include:
C. I. Reactive Yellow 1, 2, 3, 5, 11, 13, 14, 15, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 29, 35, 37, 40, 41, 42, 47, 51, 55, 65, 67, 81, 95, 116, 142, 161 etc.;
C. I. Reactive Red 1, 3, 3:1, 4, 13, 14, 17, 19, 21, 22, 23, 24, 24: 1, 25, 26, 29, 31, 32, 35, 37, 40, 41, 43, 44, 45, 46, 49, 55, 60, 66, 74, 79, 96, 97, 108, 141, 180, 218, 226, 245, etc.;
C. I. Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27, 33, 34, etc.;
C. I. Reactive Blue 1, 2, 3, 5, 7, 8, 10, 13, 14, 15, 17, 18, 19, 21, 23, 25, 26, 27, 28, 29, 32, 35, 38, 41, 49, 63, 72, 75, 80, 95, 190, etc.;
C. I. Reactive Orange 1, 2, 4, 5, 7, 12, 13, 14, 16, 20, 29, 33, 35, 38, 64, 67, 71, 72, 72: 1, 78, 82, 84, 86, 87, 91, 99, 99: 1, 107, 113, 122, 124, 125 etc.;
C. I. Reactive Black 1, 3, 4, 5, 7, 8, 11, 12, 14, 17, 21, 23, 26, 31, 32, 34, 39 and the like.

When a water-soluble dye is used, the content relative to the total amount of the water-based inkjet ink composition is not limited, but is about 0.1% by mass or more and 30% by mass or less, preferably 0.5% by mass or more and 25% by mass or less. , more preferably 1% by mass or more and 20% by mass or less, and still more preferably 5% by mass or more and 15% by mass or less.

1.1.2. Dispersed Colorant The water-based inkjet ink composition may use a dispersed colorant as a colorant. A disperse colorant is a colorant that does not dissolve or hardly dissolves in a solvent, and includes, for example, pigments and disperse dyes. The solvent-insoluble or sparingly soluble pigments and disperse dyes are not particularly limited, and include inorganic pigments, organic pigments, oil-soluble dyes, disperse dyes, and the like. The hues of the pigments and disperse dyes are also not limited, and may be so-called process colors such as cyan, magenta, yellow, and black, or so-called special colors such as blue, red, orange, white, fluorescent colors, and bright colors.

Examples of inorganic pigments that can be used include furnace black, lamp black, acetylene black, channel black and other carbon blacks (CI Pigment Black 7, etc.), iron oxide, titanium oxide, zinc oxide, silica, and the like.

As the carbon black, No. 6 manufactured by Mitsubishi Chemical Corporation is used. 2300, 900, MCF88, No. 20B, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No2200B and the like. As carbon black, color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U, special black 6, 5, 4A, 4, 250, etc. manufactured by Degussa. can be exemplified. Examples of carbon black include Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255 and 700 manufactured by Columbia Carbon. Examples of carbon black include Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, and Elftex 12 manufactured by Cabot. Furthermore, as carbon black, BONJET manufactured by Orient Chemical Industry Co., Ltd.
Examples include BLACK CW-1, CW-1S, CW-2, CW-3, M-800 and the like.

Examples of organic pigments include quinacridone-based pigments, quinacridone-quinone-based pigments, dioxazine-based pigments, phthalocyanine-based pigments, anthrapyrimidine-based pigments, anthanthrone-based pigments, indanthrone-based pigments, flavanthrone-based pigments, perylene-based pigments, diketopyrrolo Examples include pyrrole-based pigments, perinone-based pigments, quinophthalone-based pigments, anthraquinone-based pigments, thioindigo-based pigments, benzimidazolone-based pigments, isoindolinone-based pigments, azomethine-based pigments, and azo-based pigments.

As a cyan pigment, C.I. I. Pigment Blue 1, 2, 3, 15:3, 15:4, 15:34, 16, 22, 60, etc.; I. Vat Blue 4, 60 and the like, preferably C.I. I. One or a mixture of two or more selected from the group consisting of Pigment Blue 15:3, 15:4, and 60 can be exemplified.

As a magenta pigment, C.I. I. Pigment Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122, 123, 168, 184, 202, C.I. I. Pigment Violet 19, preferably C.I. I. Pigment Red 122, 202 and 209, C.I. I. One or a mixture of two or more selected from the group consisting of Pigment Violet 19 can be exemplified.

As a yellow pigment, C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154 , 155, 180, 185, etc., preferably C.I. I. One or a mixture of two or more selected from the group consisting of Pigment Yellow 74, 109, 110, 128, and 138 can be exemplified.

As an orange pigment, C.I. I. Pigment Orange 36 or 43 or a mixture thereof can be exemplified. C.I. I. Pigment Green 7 or 36 or a mixture thereof can be exemplified.

The luster pigment is not particularly limited as long as it can exhibit luster when attached to a medium. Examples include aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, and Examples include metal particles of one or more alloys (also referred to as metal pigments) selected from the group consisting of copper, and pearl pigments having pearl luster. Representative examples of pearl pigments include pigments having pearl luster and interference luster such as titanium dioxide-coated mica, fish scale foil, and bismuth oxide. Moreover, the bright pigment may be subjected to a surface treatment for suppressing reaction with water.

Moreover, metal compounds, such as a metal oxide, barium sulfate, and calcium carbonate, are mentioned as a white pigment. Examples of metal oxides include titanium dioxide, zinc oxide, silica, alumina, and magnesium oxide. Particles having a hollow structure may also be used as the white pigment.

The pigment may be used after it has been dispersed with a dispersing agent. Dispersants include poly(meth)acrylic acid, (meth)acrylic acid-acrylonitrile copolymer, (meth)acrylic acid-(meth)acrylic acid ester copolymer, vinyl acetate-(meth)acrylic acid ester copolymer Polymers, (meth)acrylic resins such as vinyl acetate-(meth)acrylic acid copolymers, vinylnaphthalene-(meth)acrylic acid copolymers, and salts thereof; styrene-(meth)acrylic acid copolymers, styrene -(meth)acrylic acid-(meth)acrylic acid ester copolymer, styrene-α-methylstyrene-(meth)acrylic acid copolymer, styrene-α-methylstyrene-(meth)acrylic acid-(meth)acrylic Styrene-based resins such as acid ester copolymers, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers and salts thereof; polymer compounds (resins) containing urethane bonds in which isocyanate groups and hydroxyl groups have reacted can be exemplified. These may be linear and/or branched, and may or may not have a crosslinked structure, urethane resins and salts thereof; polyvinyl alcohols; vinylnaphthalene-maleic acid copolymers and salts thereof; vinyl acetate-malein. acid ester copolymers and salts thereof; and water-soluble resins such as vinyl acetate-crotonic acid copolymers and salts thereof.

Commercial products of styrene-acrylic resin dispersants include, for example, X-200, X-1,
X-205, X-220, X-228 (manufactured by Seiko PMC), Nopcos Perth (registered trademark) 6100, 6110 (manufactured by San Nopco Co., Ltd.), Joncryl 67, 586, 611, 678, 680, 682, 819 (BASF company), DISPERBYK-190 (manufactured by BYK-Chemie Japan Co., Ltd.), N-EA137, N-EA157, N-EA167, N-EA177, N-EA197D, N-EA207D, E-EN10 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) etc.

Commercially available acrylic resin dispersants include BYK-187, BYK-190, BYK-191, BYK-194N, BYK-199 (manufactured by BYK Chemie Co., Ltd.), Aron A-210, A6114, AS-1100, AS- 1800, A-30SL, A-7250, CL-2 manufactured by Toagosei Co., Ltd.) and the like.

Commercially available urethane-based resin dispersants include BYK-182, BYK-183, BYK-184, BYK-185 (manufactured by BYK-Chemie Co., Ltd.), TEGO Disperse 710 (manufactured by Evonic Tego Chemi), and Borchi (registered trademark) Gen1350 ( manufactured by OMG Borschers) and the like.

A dispersing agent may be used individually by 1 type, or may use 2 or more types together. The total content of the dispersant is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 25 parts by mass or less, and even more preferably 1 mass part with respect to 50 parts by mass of the pigment. parts or more and 20 parts by mass or less, more preferably 1.5 parts by mass or more and 15 parts by mass or less. When the content of the dispersant is 0.1 parts by mass or more with respect to 50 parts by mass of the pigment, the dispersion stability of the pigment can be further enhanced. Further, when the content of the dispersant is 30 parts by mass or less with respect to 50 parts by mass of the pigment, the viscosity of the obtained dispersion can be further suppressed.

As disperse dyes and oil-soluble dyes, any coloring material that disperses without dissolving in an ink vehicle can be used, such as azo-based, metal complex salt azo-based, anthraquinone-based, phthalocyanine-based, and triallylmethane-based dyes. can be exemplified.

Disperse dyes include C.I. I. Disperse Red 60, 82, 86, 86:1, 92, 152, 154, 167:1, 191, 279, C.I. I. Disperse Yellow 64, 71, 86, 114, 153, 163, 233, 245, C.I. I. Disperse Blue 27, 60, 73, 77, 77:1, 87, 165, 165:1, 257, 367, C.I. I. Disperse Violet 26, 33, 36, 57, C.I. I. Examples include Disperse Orange 30, 41, 61, 80 and the like.

It is preferable that the dispersed colorant can be stably dispersed in the ink. For example, the surface of the coloring material may be oxidized or sulfonated with ozone, hypochlorous acid, fuming sulfuric acid, or the like to modify the surface of the coloring material particles, thereby using it as a self-dispersing coloring material. may be used by dispersing with a dispersing agent.

The pigments and disperse dyes exemplified as the above disperse colorants are examples, and one or more of these pigments and disperse dyes may be used. A combined use is also possible.

Among the coloring materials described above, when a pigment is employed in the water-based inkjet ink composition, aggregation can be effectively suppressed even though the coloring material has a relatively high aggregation property. That is, the effect of suppressing aggregation becomes more remarkable, which is more preferable.

1.2. Water The water-based inkjet ink composition according to the present embodiment contains water. Examples of water include pure water such as ion-exchanged water, ultrafiltrated water, reverse osmosis water, and distilled water, and water in which ionic impurities are reduced, such as ultrapure water. In addition, the use of water sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like can suppress the generation of bacteria and fungi when the water-based inkjet ink composition is stored for a long period of time.

The content of water is 30% by mass or more, preferably 40% by mass or more, more preferably 45% by mass or more, and still more preferably 50% by mass or more, relative to the total amount of the water-based inkjet ink composition. . The water in the water-based inkjet ink composition includes, for example, the water when the raw material contains water and the water to be added. When the water content is 30% by mass or more, the viscosity of the water-based inkjet ink composition can be relatively low. The upper limit of the water content is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less, relative to the total amount of the water-based inkjet ink composition.

1.3. 1-(2-Hydroxyethyl)-2-pyrrolidone The water-based inkjet ink composition according to the present embodiment contains 1-(2-hydroxyethyl)-2-pyrrolidone. 1-(2-Hydroxyethyl)-2-pyrrolidone is also called N-hydroxyethylpyrrolidone, 1-(2-hydroxyethyl)pyrrolidin-2-one, etc. (abbreviated as "HEP" in this specification). there is.).

HEP has amphiphilic properties, but does not have a structure in which hydrophilic and hydrophobic sites are clearly separated, compared to surfactants. Therefore, for example, it is difficult to destabilize the dispersed state of substances such as pigments, dispersed colorants, and resin particles that are dispersed in the water-based inkjet ink composition. Therefore, among surfactants and organic solvents having amphiphilic properties, HEP has the property of making it more difficult for substances dispersed in a water-based inkjet ink composition to agglomerate.

In addition, by including HEP in the water-based inkjet ink composition, it is possible to suppress the inhibitory action of a compound having an HLB value of 15 or less (described later) that tends to inhibit the dispersibility of a substance in a dispersed state. . That is, it is possible to suppress the action of reducing the dispersibility of the colorant by the compound having an HLB value of 15 or less. The inventors consider that such a phenomenon is partly caused by HEP increasing the solubility of compounds with an HLB value of 15 or less.

The content of HEP is preferably 0.5% by mass or more and 30.0% by mass or less, more preferably 1.0% by mass or more and 20.0% by mass or less, relative to the total amount of the water-based inkjet ink composition. % by mass or more and 10.0 mass % or less is more preferable.

1.4. Other Components The water-based inkjet ink composition of the present embodiment may contain the following components in addition to the above components.

1.4.1. Other Organic Solvents The water-based inkjet ink composition of the present embodiment may contain organic solvents other than HEP described above. Examples of organic solvents include alkyl polyols, glycol ethers, cyclic amides, and the like.

1.4.2.1. Alkyl Polyol The water-based inkjet ink composition of the present embodiment may contain an alkyl polyol. Alkyl polyols conceptually include polyhydric alcohols, but the alkyl polyols described in this section have a normal boiling point of less than 270.0°C. When the alkyl polyol is contained, the moisture retention of the water-based inkjet ink composition is enhanced, and the ejection stability by the inkjet method is improved, while the evaporation of moisture from the recording head during long-term standing can be effectively suppressed. can. In addition, even when using a coloring material that tends to cause clogging of nozzles, it is possible to better maintain recoverability after standing and stability of continuous ejection.

Specific examples of alkyl polyols include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol , 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl -1,5-pentanediol, 2-methylpentane-2,4-diol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, triethylene glycol, tetraethylene glycol and the like. These alkyl polyols may be used singly or in combination of two or more.

Among the alkyl polyols, the water-based inkjet ink composition more preferably contains an alkanediol having 3 or more and 6 or less carbon atoms. Examples of alkanediols having 3 to 6 carbon atoms include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,3-propanediol, 1,3- -butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol , 2,2-dimethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol. can.

When the water-based inkjet ink composition contains an alkanediol having 3 or more and 6 or less carbon atoms, the viscosity is further suppressed, and better ejection stability (continuous ejection reliability) can be obtained. In addition, the solubility and dispersibility of the coloring material can be easily improved, and good clogging recovery properties can be obtained.

1.4.2.2. Glycol Ether The water-based inkjet ink composition of the present embodiment may contain a glycol ether. Glycol ethers include monoalkyl ethers and dialkyl ethers of glycols selected from ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene glycol. can be mentioned. More specifically, methyl triglycol (triethylene glycol monomethyl ether), butyl triglycol (triethylene glycol monobutyl ether), butyl diglycol (diethylene glycol monobutyl ether), dipropylene glycol monopropyl ether and the like are typical examples. Examples include diethylene glycol monobutyl ether.

More preferably, the water-based inkjet ink composition contains one or more glycol ethers selected from glycol ethers represented by the following formula (1).
R ¹ —O—(CH ₂ —CH ₂ —O) _n —R ² (1)
(In formula (1), R ¹ represents H or an alkyl group having 1 to 4 carbon atoms, R ² represents an alkyl group having 1 to 4 carbon atoms, and n is an integer of 2 to 3 represents.)

Glycol ethers represented by formula (1) include methyltriglycol (triethylene glycol monomethyl ether), butyltriglycol (triethylene glycol monobutyl ether), butyldiglycol (diethyleneglycol monobutyl ether), triethylene glycol dimethyl ether, triethylene glycol dimethyl ether, Examples include ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, and the like.

Glycol ethers may be used in combination of multiple types. In addition, when glycol ether is used, the total blending amount is 0.5% by mass with respect to the total amount of the water-based inkjet ink composition from the viewpoint of adjusting the viscosity of the water-based inkjet ink composition and suppressing clogging due to the moisturizing effect. 30 mass % or less, preferably 1.0 mass % or more and 20 mass % or less, more preferably 3.0 mass % or more and 10.0 mass % or less.

1.4.2.3. Cyclic Amide The water-based inkjet ink composition of the present embodiment may contain a cyclic amide. The cyclic amide has the function of easily dissolving the dye described above and suppressing the solidification and drying of the water-based inkjet ink composition.

Cyclic amides include compounds having a ring structure containing an amide group. Such compounds include 2-pyrrolidone, 1-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone), 1-ethyl-2-pyrrolidone (N-ethyl-2-pyrrolidone), 1-propyl-2 -pyrrolidone, 1-butyl-2-pyrrolidone, N-vinyl-2-pyrrolidone (NVP) and other γ-lactams, β-lactams, δ-lactams, ε-caprolactam and other ε-lactams, and the like. be done. These cyclic amides may be used singly or in combination of two or more.

1.4.2.4. Other Organic Solvents The water-based inkjet ink composition of the present embodiment may contain other organic solvents. Examples of other organic solvents include lactones such as γ-butyrolactone and betaine compounds.

1.4.3. Resin Particles The water-based inkjet ink composition may contain resin particles. The resin particles can further improve the adhesion of the image formed by the water-based inkjet ink composition adhered to the recording medium. Examples of resin particles include urethane-based resins, acrylic resins (including styrene-acrylic resins), fluorene-based resins, polyolefin-based resins, rosin-modified resins, terpene-based resins, polyester-based resins, polyamide-based resins, and epoxy-based resins. , vinyl chloride-based resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate-based resins, and the like. Among them, urethane-based resins, acrylic-based resins, polyolefin-based resins, and polyester-based resins are preferable. These resin particles are often handled in the form of an emulsion, but may be in the form of powder. Also, the resin particles can be used singly or in combination of two or more.

When the water-based inkjet ink composition contains resin particles, the resulting image can have better abrasion resistance. In addition, since the dispersibility of the resin particles is less likely to be destabilized, it is easy to achieve both abrasion resistance and storage stability.

Urethane-based resin is a general term for resins having urethane bonds. In addition to urethane bonds, urethane-based resins include polyether-type urethane resins containing ether bonds in the main chain, polyester-type urethane resins containing ester bonds in the main chain, and polycarbonate-type urethane resins containing carbonate bonds in the main chain. You may In addition, as the urethane resin, commercially available products may be used, for example, Superflex 460, 460s, 840, E-4000 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Rezamin D-1060, D-2020, D-4080, D-4200, D-6300, D-6455 (trade name, manufactured by Dainichiseika Kogyo Co., Ltd.), Takelac WS-5100, WS-6021, W-512-A-6 (trade name, Mitsui Chemicals Polyurethane Co., Ltd.), Sancure 2710 (trade name, manufactured by LUBRIZOL), and Permalin UA-150 (trade name, manufactured by Sanyo Chemical Industries, Ltd.) may be used.

Acrylic resin is a general term for polymers obtained by polymerizing at least acrylic monomers such as (meth)acrylic acid and (meth)acrylic acid ester as one component. Examples include resins obtained, copolymers of acrylic monomers and other monomers, and the like. Examples thereof include acrylic-vinyl resins which are copolymers of acrylic monomers and vinyl monomers. Further, for example, the vinyl-based monomer includes styrene.

Acrylamide, acrylonitrile and the like can also be used as acrylic monomers. For resin emulsions made from acrylic resins, commercially available products may be used, such as FK-854 (trade name, manufactured by Chuo Rika Kogyo Co., Ltd.), Movinyl 952B, 718A (trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). , Nipol LX852, LX874 (trade name, manufactured by Nippon Zeon Co., Ltd.) and the like.

In this specification, the acrylic resin may be a styrene-acrylic resin described later. Moreover, in this specification, the notation of (meth)acrylic means at least one of acrylic and methacrylic.

Styrene-acrylic resins are copolymers obtained from styrene monomers and (meth)acrylic monomers, and include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid -acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, and the like. Commercially available styrene-acrylic resins may be used, for example, Joncryl 62J, 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (trade name, manufactured by BASF), Movinyl 966A, 975N (trade name, Nippon Synthetic Chemical Industry Co., Ltd.), Vinyblan 2586 (Nissin Chemical Industry Co., Ltd.), or the like may be used.

Polyolefin-based resins have olefins such as ethylene, propylene, and butylene in their structural skeletons, and known resins can be appropriately selected and used. As the olefin resin, commercially available products can be used, such as Arrowbase CB-1200 and CD-1200 (trade names, manufactured by Unitika Ltd.).

In addition, the resin particles may be supplied in the form of an emulsion. Commercially available examples of such resin emulsions include Microgel E-1002 and E-5002 (manufactured by Nippon Paint Co., Ltd. under the trade name of styrene-acrylic resin emulsion), Boncoat 4001 (manufactured by DIC, trade name, acrylic resin emulsion), Boncoat 5454 (manufactured by DIC, trade name, styrene-acrylic resin emulsion), Polysol AM-710, AM-920, AM-2300, AP -4735, AT-860, PSASE-4210E (acrylic resin emulsion), POLYSOL AP-7020 (styrene/acrylic resin emulsion), POLYSOL SH-502 (vinyl acetate resin emulsion), POLYSOL AD-13, AD
-2, AD-10, AD-96, AD-17, AD-70 (ethylene/vinyl acetate resin emulsion), Polysol PSASE-6010 (ethylene/vinyl acetate resin emulsion) (manufactured by Showa Denko KK), Polysol SAE1014 (trade name, styrene-acrylic resin emulsion, manufactured by Nippon Zeon), Saibinol SK-200 (trade name, acrylic resin emulsion, manufactured by Saiden Chemical Co., Ltd.), AE-120A (trade name, manufactured by JSR, acrylic resin emulsion) , AE373D (trade name manufactured by E-Tech, carboxy-modified styrene/acrylic resin emulsion), Seikadyne 1900W (trade name manufactured by Dainichiseika Kogyo Co., Ltd., ethylene/vinyl acetate resin emulsion), Vinyblan 2682 (acrylic resin emulsion), Vinyblan 2886 (acetic acid vinyl acrylic resin emulsion), Vinyblan 5202 (acetic acid acrylic resin emulsion) (manufactured by Nissin Chemical Industry Co., Ltd. trade name), Elitel KA-5071S, KT-8803, KT-9204, KT-8701, KT-8904, KT-0507 (Unitika Co., Ltd. trade name, polyester resin emulsion), Hitec SN-2002 (Toho Chemical Co., Ltd. trade name, polyester resin emulsion), Takelac W-6020, W-635, W-6061, W-605, W-635, W-6021 (product name of Mitsui Chemicals Polyurethane Co., Ltd., urethane resin emulsion), Superflex 870, 800, 150, 420, 460, 470, 610, 700 (product name of Daiichi Kogyo Seiyaku Co., Ltd., urethane resin emulsion) , Permaline UA-150 (manufactured by Sanyo Chemical Industries, Ltd., urethane resin emulsion), Sancure 2710 (manufactured by Nippon Lubrizol, urethane resin emulsion), NeoRez R-9660, R-9637, R-940 (Kusumoto Kasei Urethane resin emulsion manufactured by Co., Ltd.), ADEKA BONDITATER HUX-380, 290K (urethane resin emulsion manufactured by ADEKA Co., Ltd.), Movinyl 966A, Movinyl 7320 (manufactured by Nippon Synthetic Chemical Co., Ltd.), Joncryl 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 79 0, 780, 7610 (manufactured by BASF), NK Binder R-5HN (manufactured by Shin-Nakamura Chemical Co., Ltd.), Hydran WLS-210 (non-crosslinkable polyurethane: manufactured by DIC Corporation), Joncryl 7610 (manufactured by BASF) made) and the like.

When resin particles are contained in the water-based inkjet ink composition, the content of the resin particles is 0.1% by mass or more and 20% by mass or less, preferably 1% by mass or more, based on the total mass of the water-based inkjet ink composition. It is 15 mass % or less, more preferably 2 mass % or more and 10 mass % or less.

1.4.4. Surfactant The water-based inkjet ink composition according to the present embodiment may contain a surfactant. Surfactants can be used to lower the surface tension of the water-based inkjet ink composition and adjust and improve the wettability with a recording medium, for example, the penetrability into fabrics and the like. As surfactants, any of nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants can be used, and these may be used in combination. Moreover, among surfactants, acetylene glycol-based surfactants, silicone-based surfactants, and fluorine-based surfactants can be used more preferably.

The acetylene glycol surfactant is not particularly limited, but for example, Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE- F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (trade name, manufactured by Air Products and Chemicals Inc.), Olphine B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, PD-005, EXP.
4001, EXP. 4036, EXP. 4051, EXP. 4123, EXP. 4200, EXP. 4300, AF-103, AF-104, AK-02, SK-14, AE-3 (trade name, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (trade name, manufactured by Kawaken Fine Chemicals Co., Ltd.) ).

The silicone-based surfactant is not particularly limited, but preferably includes a polysiloxane-based compound. Examples of the polysiloxane-based compound include, but are not particularly limited to, polyether-modified organosiloxane. Examples of commercially available polyether-modified organosiloxanes include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (trade name, manufactured by BYK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and a specific example thereof is BYK-340 (trade name, manufactured by BYK-Chemie Japan).

When a surfactant is added to the water-based inkjet ink composition, the total amount of the surfactant is 0.01% by mass or more and 3% by mass or less, preferably 0.05% by mass, based on the entire water-based inkjet ink composition. 2% by mass or less, more preferably 0.1% by mass or more and 1.5% by mass or less, particularly preferably 0.2% by mass or more and 1% by mass or less.

In addition, when the water-based inkjet ink composition contains a surfactant, there is a tendency for the ink to be more stable when ejected from the head.

1.4.5. Chelating Agent The water-based inkjet ink composition of the present embodiment may use a chelating agent. The chelating agent can remove certain ions in the water-based inkjet ink composition.

Examples of chelating agents include EDTA, EDTA-2Na (ethylenediaminetetraacetic acid dihydrogen disodium salt), EDTA-3Na (ethylenediaminetetraacetic acid monohydrogen trisodium salt), EDTA-4Na (ethylenediaminetetraacetic acid tetrasodium salt), And ethylenediaminetetraacetic acid and its salts such as EDTA-3K (ethylenediaminetetraacetic acid monohydrogen tripotassium salt), DTPA, DTPA-2Na (diethylenetriaminepentaacetic acid disodium salt), and DTPA-5Na (diethylenetriaminepentaacetic acid pentasodium salt ), nitrilotriacetic acid and its salts such as NTA, NTA-2Na (nitrilotriacetic acid disodium salt), and NTA-3Na (nitrilotriacetic acid trisodium salt), ethylenediamine-N, N'-disuccinic acid and its salts, 3-hydroxy-2,2'-iminodisuccinic acid and its salts, L-aspartic acid-N,N'-diacetic acid and its salts, L-glutamic diacetic acid and its salts, N -(1-Carboxylatomethyl)iminodiacetic acid and its salts and N-(2-hydroxyethyl)iminodiacetic acid and its salts may be mentioned.

Examples of chelating agents other than acetic acid analogues include ethylenediaminetetramethylenephosphonic acid and its salts, ethylenediaminetetrametaphosphoric acid and its salts, ethylenediaminepyrophosphate and its salts, and ethylenediaminemetaphosphoric acid and its salts. .

When the water-based inkjet ink composition of the present embodiment contains a chelating agent, one or more selected from those exemplified above can be used.

1.4.6. pH Adjuster A pH adjuster may be added to the water-based inkjet ink composition of the present embodiment. Examples of pH adjusters include, but are not particularly limited to, acids, bases, weak acids, and appropriate combinations of weak bases. Examples of acids and bases used in such combinations include inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, potassium dihydrogen phosphate and dihydrogen phosphate. sodium, potassium carbonate, sodium carbonate, sodium hydrogencarbonate, ammonia, etc.; organic bases include triethanolamine, tripropanolamine, diethanolamine, monoethanolamine, triisopropanolamine, diisopropanolamine, trishydroxymethylamino; methane (THAM) and the like, and organic acids such as adipic acid, citric acid, succinic acid, lactic acid, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), 4-(2 -hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), morpholinoethanesulfonic acid (MES), morpholinopropanesulfonic acid (MOPS), carbamoylmethyliminobisacetic acid (ADA), piperazine-1,4-bis(2- ethanesulfonic acid) (PIPES), N-(2-acetamido)-2-aminoethanesulfonic acid (ACES), colamin hydrochloride, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES), acetamidoglycine Good buffers such as , tricine, glycinamide, and bicine, phosphate buffers, citrate buffers, Tris buffers, and the like may also be used. Furthermore, among these, as part or all of the pH adjuster, tertiary amines such as triethanolamine and triisopropanolamine, and carboxyl group-containing organic acids such as adipic acid, citric acid, succinic acid, and lactic acid, It is preferable because the pH buffering effect can be obtained more stably.

1.4.7. Ureas Urea may be used as a moisturizing agent for the water-based inkjet ink composition or as a dyeing aid for improving the dyeing property of the dye. Specific examples of ureas include urea, ethyleneurea, tetramethylurea, thiourea, 1,3-dimethyl-2-imidazolidinone and the like. When urea is contained, its content can be 1% by mass or more and 10% by mass or less with respect to the total mass of the water-based inkjet ink composition.

1.4.8. Antiseptics, Antifungal Agents, and Antirust Agents Antiseptics and antifungal agents may be used in the water-based inkjet ink composition. Examples of antiseptics and antifungal agents include sodium benzoate, pentachlorophenol sodium, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one (Zeneca Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN, Proxel LV), 4-chloro-3-methylphenol (Bayer's Preventol CMK, etc.). Examples of rust preventives include benzotriazole.

1.4.9. Sugars The water-based inkjet ink composition may contain sugars. Specific examples of sugars include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose.

1.4.10. Others As components other than the above, additives that can be commonly used in water-based inkjet ink compositions for inkjet, such as antioxidants, ultraviolet absorbers, oxygen absorbers, and dissolution aids, may be contained.

1.5. Compound with HLB value of 15 or less The water-based inkjet ink composition of the present embodiment contains a compound with an HLB value of 15 or less. At least one compound having an HLB value of 15 or less may be selected from the organic solvents, surfactants, and pH adjusters described above, or compounds not listed above may be used.

As used herein, "HLB" (value of hydrophile and lipophile balance) indicates the hydrophilic/hydrophobic balance of a compound numerically. Also, the HLB is a value calculated by the Griffin method.

Specific examples of HLB values according to the Griffin method are given below.

The HLB value of the polysiloxane surfactant is, for example, KF-6011 (HLB value = 14.5), KF-6013 (HLB value = 10), KF-6004 (HLB value = 9), KF-6043 (HLB value = 14.5), KF-643 (HLB value = 14), KF-640 (HLB value = 14), KF-351A (HLB value = 12), KF-354L (HLB value = 16), KF-945 (HLB value = 4), KF-6020 (HLB value = 4), X-22-6191 (HLB value = 2), X-22-4515 (HLB value = 5), KF-6015 (HLB value = 5) , KF-6017 (HLB value = 5), KF-6038 (HLB value = 3) [both manufactured by Shin-Etsu Silicone Co., Ltd.], FZ-2105 (HLB value = 11), L-7604 (HLB value = 13) , FZ-2104 (HLB value = 14), FZ-2116 (HLB value = 5), FZ-2120 (HLB value = 6), L-720 (HLB value = 7), L-7002 (HLB value = 7) , FZ-2123 (HLB value = 8) [both manufactured by Dow Corning Toray], SILWET L-7604 (HLB value = 13), SILWET L-7607N (HLB value = 17), SILWET FZ-2104 (HLB value = 14), or SILWET FZ-2161 (HLB value = 20), SILWET L-7001 (HLB value = 7), SILWET L-7002 (HLB value = 7), SILWET Y-7006 (HLB value = 7), or SILWET FZ-2164 (HLB value = 8) [both manufactured by Nihon Unicar Co., Ltd.].

The HLB value of the acetylene glycol-based surfactant or acetylene alcohol-based surfactant is, for example, Surfynol 61 (HLB value = 6), Surfynol 82 (HLB value = 4), Surfynol 104 (HLB value = 4), Surfynol 420 (HLB value = 4), Surfynol 440 (HLB value = 8), Surfynol SE (HLB value = 6), Surfynol SE-F (HLB value = 6), Surfynol 2502 (HLB value = 8 ), Surfynol DF110D (HLB value = 3), Surfynol 104PG50 (HLB value = 4), Surfynol 104E (HLB value = 4), Surfynol 104H (HLB value = 4), Surfynol 104A (HLB value = 4 ), Surfynol 104PA (HLB value = 4), Surfynol 104S (HLB value = 4), Surfynol 604 (HLB value = 8), Surfynol 607 (HLB value = 8), Olphine PD-002W (HLB value = 9), Dynol 604 (HLB value = 8) (all trade names, manufactured by Air Products and Chemicals Inc.), and the like.

The HLB value of the polyoxyalkylene alkyl ether is, for example, Noigen DL-0415 (HLB value = 15.0), Noigen ET-116B (HLB value = 12.0), Noigen ET-106A (HLB value = 10.9). , Noigen DH-0300 (HLB value = 4.0), Noigen YX-400 (HLB value = 18.1), Noigen EA-160 (HLB value = 15.4) (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Emulgen 1108 (manufactured by Kao Corporation, HLB value=13.4) and the like.

In addition, to exemplify the HLB value of some other compounds, polyoxyethylene lauryl ether (HLB = 9.5), sorbitan monolaurate (HLB value = 8.6), propylene glycol monolaurate (HLB value = 4.5), diethylene glycol monolaurate (HLB value = 6.1), polyoxyethylene nonylphenol (HLB value = 13.0), ethanol (HLB value = 7.9), methanol (HLB value = 8.4) , n-propanol (HLB value = 7.4), 3-methoxybutanol (HLB value = 12), oleic acid (HLB = 1), γ-butyrolactone (HLB value = 15), δ-valerolactone (HLB value = 12), diethylene glycol diethyl ether (HLB value = 10.7), dipropylene glycol dimethyl ether (HLB value = 2.5), tetraethylene glycol dimethyl ether (HLB value = 15), methyl caprylate (HLB value = 3.3) , cyclooctane (HLB value = 1), dimethyl succinate (HLB value = 6.5), dimethyl glutarate (HLB value = 7.2), 3-methoxybutyl acetate (HLB value = 5.8), etc. .

Some of the above HLB values in parentheses are excerpted from the description of Komo Tsuji/Techniques of emulsification and solubilization/published by Kogakutosho Co., Ltd.

A plurality of compounds having an HLB value of 15 or less may be contained in the water-based inkjet ink composition. The total content of compounds having an HLB value of 15 or less is 0.01% by mass or more and 3.0% by mass or less, preferably 0.05% by mass or more and 1.5% by mass or less, based on 100% by mass of the ink composition. or less, more preferably 0.1% by mass or more and 1.5% by mass or less.

Compounds with an HLB value of 15 or less are more preferably selected from surfactants. In this way, even if bubbles are generated, a good defoaming effect can be obtained by interaction with HEP.

A compound having an HLB value of 15 or less may have an HLB value of 6 or less. By selecting in this way, a better defoaming effect can be obtained. Furthermore, in this case, a surfactant with an HLB value of 10-15 may be further included. If selected in this manner, the coexistence of a surfactant with an HLB value of 10 to 15 and a compound with an HLB value of 6 or less can provide a good antifoaming effect and an image of even better image quality.

1.6. Production and physical properties of water-based inkjet ink composition The water-based inkjet ink composition can be obtained by mixing the above-described components in any order and, if necessary, performing filtration or the like to remove impurities. As a mixing method, a method of sequentially adding the materials to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer and stirring and mixing them is preferably used. As a filtration method, for example, centrifugal filtration, filter filtration, or the like can be performed as necessary.

From the viewpoint of reliability as an inkjet ink, the water-based inkjet ink composition preferably has a surface tension of 20 mN/m or more and 40 mN/m or less at 20° C., and preferably 22 mN/m or more and 35 mN/m or less. more preferred. From the same viewpoint, the viscosity of the ink at 20° C. is preferably 1.5 mPa·s or more and 10 mPa·s or less, more preferably 2 mPa·s or more and 8 mPa·s or less. One method for adjusting the surface tension and viscosity within the above ranges is to adjust the types of the above-described organic solvents and surfactants, and the amounts of these and water added.

1.7. Application of Water-Based Inkjet Ink Composition The water-based inkjet ink composition of the present embodiment is used by being filled in an inkjet recording apparatus having an ink container having an openable and closable ink inlet. An example of an inkjet recording apparatus to which the water-based inkjet ink composition is applied is described below.

The inkjet recording apparatus is an inkjet recording apparatus comprising the water-based inkjet ink composition described above, an ink container containing the water-based inkjet ink composition, and a recording head for ejecting the water-based inkjet ink composition, An ink reservoir has an openable and closable ink inlet for filling with a water-based inkjet ink composition. The inkjet recording apparatus is provided with the water-based inkjet ink composition described above.

The inkjet recording apparatus includes the water-based inkjet ink composition described above, an ink container containing the water-based inkjet ink composition, and a recording head for ejecting the water-based inkjet ink composition. It has an openable and closable ink inlet for filling the ink composition.

An example of an inkjet recording apparatus according to an embodiment will be described with reference to the drawings. The ink container is an ink tank of an inkjet printer (inkjet recording apparatus) that records (prints) an image or the like on a medium by ejecting ink onto the medium. Moreover, in the following description, the inkjet recording apparatus may be simply referred to as a recording apparatus, and the water-based inkjet ink composition may be simply referred to as an ink.

As shown in FIG. 1, the recording apparatus 21 includes a rectangular parallelepiped housing 22 whose longitudinal direction is the horizontal direction. 1 schematically illustrates the inside of a housing 22 of the recording apparatus 21 as seen through. A support base 23 whose longitudinal direction is the left-right direction is provided in the lower part of the housing 22 near the rear so that the upper surface of the support base 23 extends along the substantially horizontal direction. A sheet P, which is an example of a medium, is transported forward in the transport direction while being supported on the upper surface of the support table 23 . A guide shaft 24 extending in the left-right direction is provided above the support table 23 in the housing 22. The guide shaft 24 is provided with a carriage 26 having a recording head 25 for ejecting ink on its lower surface side. is supported. That is, the carriage 26 is supported so as to reciprocate in the left-right direction with respect to the guide shaft 24 in a state in which the guide shaft 24 is inserted through the support hole 27 penetrating in the left-right direction.

A drive pulley 28 and a driven pulley 29 are rotatably supported at positions near both ends of the guide shaft 24 in the housing 22 . An output shaft of a carriage motor 30 is connected to the drive pulley 28 , and an endless timing belt 31 partly connected to the carriage 26 is wound between the drive pulley 28 and the driven pulley 29 . . When the carriage 26 is driven by the carriage motor 30 and guided by the guide shaft 24 via the timing belt 31 to reciprocate along the horizontal direction, which is the scanning direction for the paper P, the carriage 26 is transported forward on the support base 23 . Ink is ejected onto the paper P from the recording head 25 on the lower surface side of the carriage 26 .

Further, as shown in FIG. 1, a front side of the support stand 23 on the front side of the housing 22 is provided at a position where the ink from the recording head 25 when conveyed on the support stand 23 inside the housing 22 flows. A rectangular discharge port 32 is open for discharging the paper P on which recording has been performed by ejection to the front side. At the discharge port 32, a rectangular plate-shaped discharge tray 33 capable of supporting the paper P discharged from the housing 22 is provided so as to be retractable forward in the discharge direction. Further, in the discharge port 32 , a paper feed cassette 34 capable of accommodating a plurality of sheets P used for recording in a stacked state is attached to the lower side of the discharge tray 33 so as to be freely insertable and removable in the front-rear direction.

Further, as shown in FIG. 1, the front surface and the upper surface of the housing 22 are rectangular at a position on the front surface of the housing 22 and on the left-right end side (right end side in FIG. 1) of the discharge port 32. An opening/closing door 35 having a right-angled triangular right side surface is provided so as to be freely opened/closed in the front-rear direction about a rotating shaft 36 provided at the lower end thereof and extending in the left-right direction. A window portion 37 made of a rectangular transparent member is formed on the front surface of the opening/closing door 35 . ) is visible.

Ink is supplied to the recording head 25 at a position behind the opening/closing door 35 in the housing 22 of the recording apparatus 21, that is, at a position near the front and near the end (in this case, near the right end). An ink supply unit 40 is accommodated. The ink supply unit 40 is a structure that includes a plurality (five in this embodiment) of ink containers 41 to 45 and can be handled integrally. Ink can be supplied to 45 .

As shown in FIGS. 2 and 3, the ink supply unit 40 includes five deformed box-shaped ink containers 41 to 45 elongated in the front-rear direction, and five ink containers 41 to 45 pulled out from the rear side of each of the ink containers 41 to 45. It comprises an ink supply tube 46 and a rectangular parallelepiped ink supply adapter 47 to which the ink containers 41 to 45 are assembled together. The ink replenishing adapter 47 is cut in the front half of the upper portion of each of the ink containers 41 to 45 in a state in which the ink containers 41 to 45 are arranged side by side with the thickness direction of the ink containers 41 to 45 oriented horizontally. It is integrated with the ink containers 41 to 45 by being attached to the stepped portion 48 . Incidentally, as shown in FIG. 1, the ink supply tubes 46 pulled out from the ink containing bodies 41 to 45 are connected to an ink flow path (not shown) formed in the carriage 26, and through the ink flow path. It is connected to the recording head 25 . The ink supply adapter 47 may constitute a part of the housing 22 covering the ink containers 41-45, or may be formed integrally with the ink containers 41-45.

As shown in FIGS. 4 and 5, each of the ink containers 41 to 45 has an ink storage chamber 49 in which the ink composition IK can be stored. In the case of this embodiment, black ink is stored in the ink storage chamber 49 of the ink container 41 located at the right end in the horizontal direction. Color inks other than black (cyan, magenta, yellow, etc.) are stored in the ink storage chambers 49 of the other ink storage bodies 42 to 45 arranged on the left side of the rightmost ink storage body 41 in the horizontal direction. In addition, the liquid surface of the ink composition IK in the ink storage chamber 49 is made visible on the front wall portion of the ink containing bodies 41 to 45, which is visible through the window portion 37 on the front surface of the housing 22. A viewing portion 50 made of transparent resin is provided. In the visible portion 50, a guideline for the upper limit of the liquid level of the ink composition IK stored in the ink storage chamber 49 (an example of a guideline for the amount of ink that can be injected without causing the ink to overflow from the ink inlet 53). and a lower limit mark 52 indicating a guideline for the lower limit (for example, a guideline for prompting ink replenishment).

As shown in FIG. 4, ink inlets 53 (ink inlets) that can be opened and closed that allow ink to flow into the ink storage chamber 49 from the outside are provided above the horizontal portions of the stepped portions 48 of the ink containers 41 to 45. ) is provided. The ink inlet 53 includes a needle 56 extending vertically upward and having channels 54 and 55 communicating between the inside and the outside of the ink storage chamber 49 . The channels 54, 55 of the needle 56 consist of two channels 54, 55 arranged radially side-by-side about the needle 56, each with a tip opening, one of the two channels 54, 55 The flow path 54 (on the right side in FIG. 4) has a lower tip opening and a larger cross-sectional area than the flow path 55 on the other side (on the left side in FIG. 4). A remaining amount sensor 57 for detecting the remaining amount of the ink composition IK in the ink storage chamber 49 is provided in the lower rear portion of the ink storage chamber 49 . Note that the remaining amount sensor 57 may not be provided.

As shown in FIGS. 2 to 5, the ink replenishing adapter 47 has an upper surface 58 which is a horizontal surface along a direction orthogonal (intersecting) with the direction in which the needle 56 extends. A through hole 60 penetrating in the direction is formed as an ink inlet forming portion. The through-hole 60 is composed of a circular ink inlet 53 in which the needle 56 is arranged in the center, and a pair of front and rear rectangular holes connected to the front and rear of the ink inlet 53. 45 is closed by a horizontal portion of a stepped portion 48 projecting upward from the needle 56 .

Therefore, in the through-hole 60, a pair of front and rear rectangular holes whose lower openings are blocked are provided in a region outside the ink inlet 53 in the radial direction centered on the ink inlet 53, in the direction in which the needle 56 extends. A pair of front and rear recesses 61 opening upward are formed so as to be symmetrical about the ink inlet 53 with the vertically downward direction as the depth direction. That is, in the ink replenishing adapter 47 integrated with the ink containers 41 to 45, there are a plurality of points (in this case, front and back) that are symmetrical about the ink inlet 53 in the area outside the ink inlet 53 including the needle 56. , two concave portions 61 forming a pair are formed. In this case, the tip of the needle 56 arranged at the center of the circular ink inlet 53 is the upper surface of the ink replenishing adapter 47, which is the opening edge of the through hole 60 containing the ink inlet 53 and the recess 61. It is located closer to the ink storage chamber 49 than 58 . That is, the upper surface 58 of the ink supply adapter 47 extends in a direction intersecting the extending direction of the needle 56 at a position outside the tip of the needle 56 in the extending direction of the needle 56 . On the other hand, the lower surface 59 of the ink supply adapter 47 functions as a tank engaging portion that collectively engages the plurality of ink containers 41 to 45 arranged side by side in the horizontal direction from above.

In addition, of the upper surface 58 of the ink supply adapter 47, the peripheral portion of the upper opening edge of each through-hole 60 is colored with a specific color. That is, it is colored in the same color as the ink stored in the ink storage chambers 49 of the ink containers 41 to 45 into which the ink flows through the ink inlets 53 of the through holes 60 . In this regard, in the peripheral portion of the upper opening edge of each through hole 60 in the ink supply adapter 47, the ink containing bodies 41 to 45 are stored therein, in which the ink inlet 53 of the through hole 60 and the ink storing chamber 49 communicate with each other. It functions as a first part that externally presents information related to the ink that is being used. Incidentally, the ink stored in the ink containers 41 to 45 is not particularly limited. Since black or gray black ink is to be stored, the peripheral portion of the upper opening of the through-hole 60 where the ink inlet 53 communicating with the ink storage chamber 49 of the ink container 41 is arranged is colored black or gray. .

In addition, on the inner surface of the recess 61 (specifically, the inner surface along the vertical direction), a horizontal surface is provided at a position closer to the bottom surface than the upper opening edge of the recess 61 (that is, the horizontal portion side of the stepped portion 48). A first concave-convex portion (first key structure portion) 62 having a characteristic concave-convex shape in the direction is provided so as to extend along the depth direction of the concave portion 61 (in other words, along the direction of the central axis of the ink inlet 53). ing. As shown in FIGS. 2 and 3, the first concave-convex portion 62 is provided for each of the ink inlets 53 of the plurality (five in this embodiment) of the ink containers 41 to 45 . Therefore, in the ink replenishment adapter 47, each through-hole 60 has a rectangular concave portion 61 in each through-hole 60 formed at a position corresponding to each of the ink containers 41 to 45 in the vertical direction. A first uneven portion 62 different from the first uneven portion 62 provided on the inner surface of the concave portion 61 of 60 is formed. That is, these first concave-convex portions 62 are formed in the ink bottle 63 (see FIG. 6) having an ink outlet 65 (see FIG. 6, etc.) connected to the ink inlet 53 in the through hole 60 in which the first concave-convex portion 62 is formed. etc.) can be identified. It should be noted that "the position closer to the bottom than the edge of the upper opening of the recess 61" means that the position should be set back from the edge of the opening toward the bottom even if only slightly.

Next, the ink bottle 63 will be described as an ink supply container that constitutes an ink replenishment system together with the ink containers 41 to 45 and supplies ink to the ink containers 41 to 45 when the remaining amount of ink is low. The ink bottle 63 contains the water-based inkjet ink composition described above.

As shown in FIGS. 6 to 8, the ink bottle 63 is provided with a cylindrical container main body 64 as its main body and at the tip of the container main body 64, so that the ink can flow out from the ink bottle 63. and a container addition portion 67 attached to the ink outlet forming portion 66 so as to surround the ink outlet 65 . The ink outlet 65 of the ink outlet forming portion 66 is covered with a bottomed cylindrical cap 68 including the container addition portion 67 around it, so that the ink bottle 63 is hidden from the outside when the ink bottle 63 is stored. That is, a male screw portion 69 is formed on the outer peripheral surface of the cylindrical lower end portion of the container attachment portion 67 , and a female screw portion (not shown) is formed on the inner peripheral surface of the cap 68 . By screwing the female threaded portion of the cap 68 onto the male threaded portion 69 , the cap 68 is attached to the tip of the ink bottle 63 so as to cover the ink outlet 65 .

The entire outer surface of the container addition portion 67 is colored in a specific color. That is, it is colored in the same color as the ink contained in the container main body 64 to which the container adding portion 67 is added. Incidentally, the outer surface of the container addition portion 67 in the ink bottle 63 containing black or gray ink is colored black or gray. A plurality of (four in this embodiment) protrusions 70 are formed at equal angular intervals (eg, at intervals of 90 degrees) on the outer peripheral surfaces of the base ends of the container body 64 and the cap 68 . Incidentally, these protrusions 70 are formed to prevent the cylindrical ink bottle 63 from rolling. Furthermore, for example, the container main body 64 of the ink bottle 63 that contains black ink may be formed to be thicker than the container main body 64 of the ink bottle 63 that contains other color inks. In that case, the ink outlet forming portion 66 may have the same thickness and shape for black ink and other color inks.

Further, as shown in FIGS. 6 to 8, above the cylindrical lower end of the container attachment portion 67 having a male threaded portion 69 formed on the outer peripheral surface thereof, ink is distributed radially from the ink outlet 65 as a center. A convex portion 71 is formed in a region outside the outlet 65 so as to protrude upward in the direction of the central axis of the ink outlet 65 and in the direction opposite to the container main body 64 from the ink outlet 65 . The convex portion 71 is a second fitting portion that can be fitted with the concave portion 61 of the upper surface 58 of the ink supply adapter 47 as a first fitting portion when inserting the tip of the needle 56 on the side of the ink inlet 53 into the ink outlet 65 . It functions as a fitting portion, and is provided so as to form a pair with the ink outlet 65 sandwiched therebetween in the same manner as the pair of recesses 61 sandwiching the ink inlet 53 from the front and rear. 6 and 7, the convex portion 71 is formed inside the outer peripheral surface of the container main body portion 64 in the radial direction centering on the ink outlet 65 in the ink bottle 63. As shown in FIGS.

As shown in FIGS. 6 and 9, the outer surface of each convex portion 71 (right and left side surfaces in FIGS. 6 and 9) is provided with the first uneven portion (the first uneven portion) formed on the inner surface of the concave portion 61 of the ink supply adapter 47. As shown in FIGS. A second concave-convex portion (second key structure portion) 72 that can be engaged with the first key structure portion) 62 is formed. The second concave-convex portion 72 is provided so as to extend along the projecting direction of the convex portion 71 (in other words, the direction of the central axis of the ink outlet 65). When the second concave-convex portion 72 is engaged with the first concave-convex portion 62, the ink outlet 65 of the ink bottle 63 is connected to the ink inlet 53 of the ink containers 41-45.

Moreover, between the cylindrical lower end portion of the container attachment portion 67 formed with the male threaded portion 69 and the convex portion 71 formed with the second concave-convex portion 72 , the center axis of the ink outlet 65 is orthogonal (intersects). A planar positioning portion 73 is provided so as to be positioned radially outward of the ink outlet 65 when the ink outlet 65 is viewed in the direction of its central axis. That is, the positioning portion 73 constitutes a part of the outer surface of the container addition portion 67, which is a part of the outer surface of the ink bottle 63, and is located closer to the container main body than the tip of the convex portion 71 in the direction of the central axis of the ink outlet 65. It is provided at a position on the 64 side. Since the positioning portion 73 is provided in the container addition portion 67 that is added to the ink outlet forming portion 66 in the ink bottle 63, it is a separate member from the ink outlet forming portion 66, and the ink outlet It can be said that it is a configuration provided outside the forming portion 66 .

Further, as shown in FIG. 9, in the ink outlet 65 formed in the ink outlet forming portion 66, a valve 74 made of an elastic member such as a silicone film is provided for sealing the ink outlet 65 so that the ink outlet 65 can be opened and closed. ing. The valve 74 is provided at a position where the positioning portion 73 is on the container body portion 64 side in the direction of the central axis of the ink outlet 65 (see FIG. 14, for example). The valve 74 is provided with a plurality of (three in this embodiment) slits 75 that intersect at equal angular intervals (for example, 120-degree intervals) with the center of the valve 74 as the point of intersection. It is configured to be opened by being pushed and spread from the outside of 65 to the inside. That is, when the tip of the needle 56 on the side of the ink inlet 53 is inserted into the ink outlet 65, the valve 74, which is a normally closed valve, is pushed inward by the tip of the needle 56 to open.

At this time, the positioning portion 73 abuts on the upper surface 58 of the ink supply adapter 47 in which the through hole 60 including the ink inlet 53 and the recess 61 is formed outside the ink outlet 65 in the radial direction. , the valve 74 is positioned with respect to the ink containing bodies 41 to 45 in the direction of the central axis. In this respect, the upper surface 58 of the ink supply adapter 47 serves as a positioning portion for the ink bottle 63 when the valve 74 of the ink outlet 65 of the ink bottle 63 is opened to supply ink to the ink containers 41 to 45. It is a part of the ink containers 41 to 45 with which the 73 abuts, and functions as a receiving surface for receiving the planar positioning portion 73 .

As shown in FIGS. 10 and 11, the container main body 64 of the ink bottle 63 is a bottle-shaped member having an ink containing chamber 76 capable of containing the ink composition IK therein. A male threaded portion 78 is formed on the outer peripheral surface of the portion 77 . On the other hand, the ink outlet forming portion 66 provided at the upper end portion of the container body portion 64 includes a large diameter portion 79 located on the outer peripheral side of the neck portion 77 of the container body portion 64 and a position farthest away from the container body portion 64 . It has a small diameter portion 80 forming the outlet 65 and an intermediate portion 81 connecting between the large diameter portion 79 and the small diameter portion 80 . A female threaded portion 82 formed on the inner peripheral surface of the large-diameter portion 79 is screwed into a male threaded portion 78 formed on the outer peripheral surface of the neck portion 77 of the container main body portion 64, whereby the ink outlet forming portion 66 is formed. It is attached to the upper end of the container body 64 .

A container addition portion 67 attached to the ink outlet forming portion 66 of the ink bottle 63 so as to surround the ink outlet 65 has a cylindrical lower end portion having a male screw portion 69 formed on the outer peripheral surface thereof. It constitutes a joint portion 83 that is joined to the upper end surface of the large diameter portion 79 of the ink outlet forming portion 66 . The surface regions of the inner peripheral surface of the joint portion 83 facing each other in the front-rear direction are in surface contact with the front and rear outer surfaces of the intermediate portion 81 of the ink outlet forming portion 66 . It is joined to the large diameter portion 79 .

Next, the operation of the ink replenishing system configured as described above will be described below, focusing on the operation of replenishing ink to the ink containers 41 to 45 of the ink supply unit 40 using the ink bottle 63 .

As a premise, as shown in FIG. 2, the liquid level of the black ink in the ink containing body 41 located on the rightmost side among the plurality of ink containing bodies 41 to 45 arranged side by side is visually recognized. Since the height is lowered to the lower limit mark 52 marked on the lower portion of the portion 50, the case of replenishing the ink container 41 with ink will be described below. It is also assumed that the ink bottle 63 used for ink supply contains a sufficient amount of black ink, and that the cap 68 has been removed from the ink bottle 63 in advance. Further, the shape of the second uneven portion 72 formed on the outer surface of the convex portion 71 of the ink bottle 63 is the first shape formed on the inner surface of the concave portion 61 located before and after the ink inlet 53 to the ink container 41 . It corresponds to the shape of the concave and convex portion 62 and can be engaged with the concave portion 61 as the convex portion 71 is inserted.

When replenishing the ink container 41 with ink, the user first rotates the opening/closing door 35 of the housing 22 forward about the rotating shaft 36 from the closed state shown in FIG. Then, in the ink supply unit 40, the upper surface 58 of the ink supply adapter 47, in which the ink inlets 53 to the ink containers 41 to 45 are formed, is exposed to the outside of the housing 22, and the user can select the desired ink inlet 53. , the ink outlet 65 of the ink bottle 63 can be connected from above.

Therefore, as shown in FIGS. 12 and 13, the user turns the ink bottle 63 containing the ink composition used for ink replenishment upside down so that the ink outlet 65 is the rightmost through hole in the ink replenishment adapter 47. It is held so as to be positioned above 60 . That is, the central axis of the ink outlet 65 of the ink bottle 63 is aligned with the central axis of the ink inlet 53 of the ink container 41 to be replenished with ink. At this time, the user can identify the color (second portion) colored in the container addition portion 67 of the ink bottle 63 held in the hand and the ink inlet 53 of the ink container 41 to be replenished with ink at that time. Compare with the color (first portion) colored around the upper opening edge of the provided through-hole 60 . If the colors are the same (black in this case), it is confirmed that the user is holding the ink bottle 63 suitable for the current ink replenishment, and the subsequent work for ink replenishment is started.

Then, the ink bottle 63 is lowered from the state shown in FIGS. 12 and 13, and the convex portion 71 of the ink bottle 63 is inserted into the concave portion 61 of the ink supply adapter 47 integrated with the ink container 41 . Then, by realizing the insertion state of the convex portion 71 into the concave portion 61, the coincidence state of the central axis of the ink outlet 65 with the central axis of the ink inlet 53 is ensured. In this case, since the concave portion 61 is positioned symmetrically with respect to the needle 56 which is the center of the ink inlet 53 , the convex portion 71 can be inserted into any of the concave portions 61 . Therefore, the user does not need to rotate the ink bottle 63 around the central axis of the ink outlet 65 many times to check the appropriate positional relationship between the concave portion 61 and the convex portion 71 , and the user can adjust the convex portion 71 to the concave portion 61 . Insertion work can be easily performed.

However, at this point, the protrusion 71 is only slightly inserted into the recess 61, and the tip of the needle 56 positioned at the center of the ink inlet 53 is also slightly protruding from the tip of the protrusion 71, thus opening the ink outlet 65. Although it is inserted inside, it does not reach the valve 74 positioned deep inside the ink outlet 65 . The reason for this is that, as shown in FIG. 13, the tip of the projection 71 is located closer to the top surface 58 of the ink supply adapter 47 on which the opening edge of the recess 61 is located than the distance L1 between the upper end of the first recess 62 in the recess 61 and the tip of the projection 71 . and the valve 74 in the ink outlet 65 is longer. Therefore, when the protrusion 71 is further inserted downward in the depth direction of the recess 61 from this state, the second protrusion 72 on the outer surface of the protrusion 71 engages the first protrusion 62 on the inner surface of the recess 61 . match. Then, while maintaining the engaged state, when the convex portion 71 is further inserted toward the bottom side in the depth direction of the concave portion 61 , the tip of the needle 56 of the ink inlet 53 reaches the position of the valve 74 of the ink outlet 65 . Finally, the valve 74 is opened.

That is, as shown in FIGS. 14 and 15, the tip of the needle 56 pushes the slit 75 upward from the bottom of the valve 74 (that is, from the outside to the inside of the ink outlet 65), thereby opening the valve 74. Open the valve. As a result, the ink outlet 65 of the ink bottle 63 and the needle 56 of the ink inlet 53 of the ink container 41 are connected, and the ink composition is supplied from the ink bottle 63 to the ink container 41 . At this time, one of the two flow paths 54 and 55 of the needle 56 of the ink inlet 53 is opened by opening the valve 74 so that the ink flowed out from the ink outlet 65 is first touched by the tip opening. It functions as an ink channel for circulating ink, and the other channel functions as an air channel for circulating air. For example, when the user tries to connect the ink outlet 65 to the ink inlet 53 with the ink bottle 63 tilted, the flow of the two flow paths 54 and 55 that becomes the ink flow path is determined by the difference in the tilting direction. The road will change.

If the second concave-convex portion 72 does not engage with the first concave-convex portion 62 after the convex portion 71 is inserted into the concave portion 61, the user may mistakenly select the ink bottle 63 of a color other than black at that point. You can recognize that you are trying to insert In this case, if the upper end of the first concave-convex portion 62 is positioned at the same height as the opening edge of the concave portion 61, the engagement of the second concave-convex portion 72 with the first concave-convex portion 62 is rejected. In addition, since the insertion of the projection 71 into the recess 61 is also rejected, the user may try to insert the projection 71 into the recess 61 many times, wasting work time. be. In this regard, in the present embodiment, since the height of the first uneven portion 62 is lower than the opening edge of the recess 61 , the protrusion 71 is guided toward the bottom surface side in the depth direction of the recess 61 when inserted into the recess 61 . This makes it easier to do so, and wastefully lengthening the work time is also suppressed.

14, 16 and 17, the ink bottle 63 is positioned when the needle 56 of the ink inlet 53 of the ink container 41 opens the valve 74 in the ink outlet 65 of the ink bottle 63. The portion 73 abuts on the upper surface 58 of the ink supply adapter 47 which is a part of the ink containing body 41 side. That is, the ink bottle 63 is positioned in the direction of the central axis of the ink outlet 65 with respect to the needle 56 on the side of the ink container 41 by the contact between the positioning portion 73 and the upper surface 58 of the ink supply adapter 47. is opened.

In this case, since the positioning portion 73 is positioned radially outward of the ink outlet 65 , the ink bottle 63 is stably held in a posture in which the ink outlet 65 is connected to the ink inlet 53 . 14 and 15, when the positioning portion 73 of the ink bottle 63 abuts against the top surface 58 of the ink supply adapter 47, the ink inlet 53 where the proximal end of the needle 56 is located is located. A gap exists between the bottom surface and the tip of the ink outlet 65 of the ink bottle 63 . Therefore, although ink tends to accumulate on the bottom surface of the ink inlet 53 where the base end of the needle 56 is located, it is also possible to prevent the accumulated ink from adhering to the tip of the ink outlet 65 and staining the ink bottle 63 . .

14 and 16, when the ink supply from the ink bottle 63 to the ink containing body 41 is completed, the liquid level of the ink in the ink containing body 41 is higher than the upper limit mark 51 of the visual recognition portion 50. is still low, the same black ink bottle 63 may be used to replenish the ink up to the upper limit mark 51 . The ink replenishing operation as described above is performed in the same manner for the ink containers 42 to 45 of other colors than the ink container 41 of the ink composition (black or gray ink composition).

According to the above-described inkjet recording apparatus, by applying the water-based inkjet ink composition described above, air bubbles are generated in the water-based inkjet ink composition even when the ink container has an ink inlet that can be opened and closed. can be suppressed, and the generation of aggregates can be suppressed. That is, in an ink container having an openable and closable ink inlet, even in a situation where a user or the like opens and closes the ink inlet and the water-based inkjet ink composition is likely to dry, 1-(2-hydroxyethyl) Due to the interaction between -2-pyrrolidone and the compound having an HLB value of 15 or less, foaming and aggregation of the coloring material can be suppressed, and an image with good color development can be formed.

1.8. Effects, etc. According to the water-based inkjet ink composition of the present embodiment, when it is used in an inkjet recording apparatus having an ink container having an ink inlet that can be opened and closed, the generation of air bubbles can be suppressed and the generation of aggregates can be suppressed. can be suppressed. That is, the water-based inkjet ink composition contains 1-(2-hydroxyethyl)-2-pyrrolidone and a compound having an HLB value of 15 or less, so that foaming and aggregation of the coloring material can be suppressed, and good Image quality (graininess) can be formed.

2. Inkjet Recording Method The inkjet recording method of the present embodiment includes ejecting the water-based inkjet ink composition from a recording head and attaching it to a recording medium. That is, the inkjet recording method of the present embodiment includes a step of ejecting the water-based inkjet ink composition from a recording head and attaching it to a recording medium.

According to this inkjet recording method, the aqueous inkjet ink composition contains 1-(2-hydroxyethyl)-2-pyrrolidone and a compound having an HLB value of 15 or less, so that the aqueous inkjet ink composition foams, Aggregation of the coloring material can be suppressed, and an image with good color development can be formed.

The recording medium is not particularly limited, and may or may not have a liquid-absorbing recording surface. Therefore, the recording medium is not particularly limited, and for example, paper, film, cloth, metal, glass, polymer, etc. can be used. A transfer sheet for sublimation transfer to a recording medium can also be a recording medium.

The step of applying the water-based inkjet ink composition to the recording medium can be performed using the inkjet recording apparatus described above. That is, the water-based inkjet ink composition is applied to the recording medium by filling the recording head so that the water-based inkjet ink composition can be ejected from a predetermined nozzle, and ejecting the water-based inkjet ink composition onto the recording medium at a predetermined timing in that state. can be performed.

Further, the recording method of the present embodiment may appropriately include a step of heating the recording medium. The step of heating the recording medium can be performed, for example, by using the above-described drying means or the like when using an inkjet recording apparatus. In addition, it can be carried out not only by the inkjet recording apparatus, but also by any appropriate drying means. The image obtained by this is dried, and the bleeding of the image can be suppressed, and the image can be fixed more efficiently.

The recording method of the present embodiment can further optionally include other steps, such as a step of applying another composition, a washing step, and the like. According to the recording method of the present embodiment, since the water-based inkjet ink composition described above is used, foaming of the water-based inkjet ink composition and aggregation of the coloring material can be suppressed, and an image with good image quality (granularity) can be formed. be able to.

3. Examples Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Hereinafter, "%" is based on mass unless otherwise specified.

3.1. Preparation of water-based inkjet ink composition Each component was placed in a container so as to have the composition shown in Table 1, mixed and stirred with a magnetic stirrer for 2 hours, and then filtered through a membrane filter with a pore size of 5 μm. A water-based inkjet ink composition according to the example was obtained.

In the table, the components described by abbreviations and trade names are as follows.
・Chromo Fine Blue C.I. I. Pigment Blue 15:3: (pigment, manufactured by Dainichiseika Kogyo Co., Ltd.)
・ BAYSCRIPT Cyan BA: (dye, manufactured by Lanxess)
・TEGmBE: triethylene glycol monobutyl ether ・HEP: 1-(2-hydroxyethyl)-2-pyrrolidone ・Olfine E1010: acetylene glycol surfactant (manufactured by Nissin Chemical Industry Co., Ltd.)
・ EXP4200: Acetylene glycol-based surfactant (manufactured by Nissin Chemical Industry Co., Ltd.)
- Surfynol DF110D: acetylene glycol surfactant (manufactured by Air Products and Chemicals. Inc.)
- Surfynol 104PG50: acetylene glycol surfactant (manufactured by Air Products and Chemicals. Inc.)
・Takelac W6061: Urethane resin emulsion (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.)

Also, in the table, the HLB value is entered for the surfactant.

3.2. Evaluation method 3.2.1. Aggregation 100 g of ink was sealed in an aluminum pack and left in a constant temperature bath at 70° C. for 6 days. After taking out the ink from the constant temperature bath, the ink was diluted 5000 times with pure water. The particle size of the diluted ink was measured with a Nanotrac (manufactured by Nikkiso). Based on the obtained average particle size, the cohesiveness (storage stability) of the ink was evaluated as follows.
A: -20 or more and less than 20 nm B: 20 nm or more and less than 50 nm C: 50 nm or more

3.2.2. Foaming Each ink of Examples and Comparative Examples is placed in a sample bottle to a height of 1/10 of the sample bottle, stirred for 1 minute and allowed to stand. evaluated. Evaluation criteria are shown below.
A: Less than 10% of ink height B: 10% or more and less than 100% of ink height C: 100% or more of ink height

3.2.3. Evaluation of image quality (granularity) For the inks of Examples and Comparative Examples, using an inkjet printer EP-803A (manufactured by Seiko Epson Corporation), an inkjet recording medium (photographic paper <glossy>: model number KA450PSK (manufactured by Seiko Epson Corporation) ) and 60° glossiness = 41) were printed at a duty of 30% or 50% and evaluated according to the following criteria.
(Evaluation criteria)
A: There is no image roughness even at a duty of 30%.
B: When the duty is 30%, image roughness is observed, but when the duty is 50%, there is no image roughness.
C: Image roughness is observed even at a duty of 50%.

3.3. Evaluation Results The water-based inkjet ink composition of each example containing a coloring material, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound having an HLB value of 15 or less is an ink that can be opened and closed. It was found that when used in an inkjet recording apparatus having an ink container with an inlet, the generation of air bubbles and aggregates could be suppressed, and recording with good image quality (granularity) could be performed. did.

The embodiments and modifications described above are examples, and the present invention is not limited to these. For example, it is also possible to appropriately combine each embodiment and each modification.

The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations that have the same function, method and result, or configurations that have the same purpose and effect. Moreover, the present invention includes configurations obtained by replacing non-essential portions of the configurations described in the embodiments. In addition, the present invention includes a configuration that achieves the same effects or achieves the same purpose as the configurations described in the embodiments. In addition, the present invention includes configurations obtained by adding known techniques to the configurations described in the embodiments.

The following content is derived from the embodiment and modification described above.

The water-based inkjet ink composition is
Containing a coloring material, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound having an HLB value of 15 or less,
It is used by being filled in an ink jet recording apparatus having an ink containing body having an openable and closable ink inlet.

According to this water-based inkjet ink composition, when used in an inkjet recording apparatus having an ink container having an ink inlet that can be opened and closed, it is possible to suppress the generation of air bubbles while maintaining good image quality (granularity), and , the generation of aggregates can be suppressed. That is, the water-based inkjet ink composition contains 1-(2-hydroxyethyl)-2-pyrrolidone and a compound having an HLB value of 15 or less, so that foaming and aggregation of the coloring material can be suppressed, and good Image quality (graininess) can be formed.

In the water-based inkjet ink composition,
The compound having an HLB value of 15 or less may be a surfactant.

According to this water-based inkjet ink composition, even if bubbles are generated, the defoaming effect is better.

In the water-based inkjet ink composition,
The compound having an HLB value of 15 or less may have an HLB value of 6 or less.

According to this water-based inkjet ink composition, a better defoaming effect can be obtained.

In the water-based inkjet ink composition,
A surfactant with an HLB value of 10-15 may be further included.

According to this water-based inkjet ink composition, images of even better image quality can be obtained.

In the water-based inkjet ink composition,
The coloring material may be a pigment.

According to this water-based inkjet ink composition, aggregation can be suppressed even though the colorant has a relatively high aggregation property. That is, the aggregation suppressing effect is more remarkable.

In the water-based inkjet ink composition,
It may further contain resin particles.

According to this water-based inkjet ink composition, the abrasion resistance of the image can be improved. In addition, since the dispersibility of the resin particles is less likely to be destabilized, it is easy to achieve both abrasion resistance and storage stability.

Inkjet recording equipment
the water-based inkjet ink composition described above;
an ink containing body containing the water-based inkjet ink composition;
a recording head that ejects the water-based inkjet ink composition;
An inkjet recording device comprising
The ink container has an openable and closable ink inlet for filling the water-based inkjet ink composition.

According to this inkjet recording apparatus, even if it has an ink container having an openable and closable ink inlet, it is possible to suppress the generation of air bubbles in the water-based inkjet ink composition and to suppress the generation of aggregates. That is, the water-based inkjet ink composition contains 1-(2-hydroxyethyl)-2-pyrrolidone and a compound having an HLB value of 15 or less, so that foaming and aggregation of the coloring material can be suppressed, and good image quality can be obtained. (graininess) images can be formed.

Inkjet recording method
It includes ejecting the water-based inkjet ink composition described above from a recording head and attaching it to a recording medium.

According to this inkjet recording method, the aqueous inkjet ink composition contains 1-(2-hydroxyethyl)-2-pyrrolidone and a compound having an HLB value of 15 or less, so that the aqueous inkjet ink composition foams, Aggregation of the coloring material can be suppressed, and an image with good image quality (granularity) can be formed.

DESCRIPTION OF SYMBOLS 21... Recording apparatus, 22... Housing, 23... Support base, 24... Guide shaft, 25... Recording head, 26... Carriage, 27... Support hole, 28... Driving pulley, 29... Follower pulley, 30... Carriage motor, 31 Timing belt 32 Discharge port 33 Discharge tray 34 Paper feed cassette 35 Open/close door 36 Rotating shaft 37 Window 40 Ink supply unit 41 to 45 Ink container 46 Ink supply tube 47 Ink supply adapter 48 Stepped portion 49 Ink storage chamber 50 Visible portion 51 Upper limit mark 52 Lower limit mark 53 Ink inlet 54, 55 Flow path 56 Needle (ink inlet channel portion), 57 Remaining amount sensor, 58 Top surface (receiving surface), 59 Bottom surface (tank engagement portion), 60 Through hole, 61 Concave portion (first fitting portion) , 62... First uneven portion (identifying portion), 63... Ink bottle, 64... Container body, 65... Ink outlet, 66... Ink outlet forming part, 67... Container addition part, 68... Cap, 69... Male screw part, 70...Protrusion 71...Convex part (second fitting part) 72...Second uneven part 73...Positioning part 74...Valve 75...Slit 76...Ink storage chamber 77...Neck part 78...Male screw Part 79... Large diameter part 80... Small diameter part 81... Intermediate part 82... Female screw part 83... Joint part L1... Distance L2... Distance P... Paper IK... Ink composition

Claims (9)

Containing a coloring material, water, 1-(2-hydroxyethyl)-2-pyrrolidone, and a compound having an HLB value of 15 or less,
A water-based inkjet ink composition that is used by being filled in an inkjet recording apparatus having an ink container having an ink inlet that can be opened and closed. In claim 1,
A water-based inkjet ink composition, wherein the compound having an HLB value of 15 or less is a surfactant. In claim 1 or claim 2,
The water-based inkjet ink composition, wherein the compound having an HLB value of 15 or less has an HLB value of 6 or less. In any one of claims 1 to 3,
A water-based inkjet ink composition further comprising a surfactant having an HLB value of 10-15. In any one of claims 1 to 4,
A water-based inkjet ink composition, wherein the coloring material is a pigment. In any one of claims 1 to 5,
A water-based inkjet ink composition further containing resin particles. In any one of claims 1 to 6,
A water-based inkjet ink composition which is used by being filled from the ink inlet into a recording apparatus comprising an openable and closable ink inlet and an ink containing body for containing the injected ink. The water-based inkjet ink composition according to any one of claims 1 to 7;
an ink containing body containing the water-based inkjet ink composition;
a recording head that ejects the water-based inkjet ink composition;
An inkjet recording device comprising
The inkjet recording apparatus, wherein the ink containing body has an openable and closable ink inlet for filling the water-based inkjet ink composition. An inkjet recording method, comprising ejecting the water-based inkjet ink composition according to any one of claims 1 to 7 from a recording head and attaching it to a recording medium.

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