JP6716096B2 - Ink, ink container, inkjet recording method, inkjet recording apparatus - Google Patents

Description

The present invention relates to an ink, an ink container, an inkjet recording method, and an inkjet recording device.

The ink jet recording method is a recording method in which ink droplets are ejected from extremely fine nozzles and the ink droplets are attached to a recording medium to form characters and images. This method has been widely used in recent years because it has an advantage that full color can be easily obtained as compared with other recording methods and a high-resolution image can be obtained even with an apparatus having a simple structure.

As an ink used in the inkjet recording system, there is a pigment-based ink. Since pigments are superior to dyes in terms of water resistance and weather resistance, inks using pigments as colorants have been mainly used in recent years.
In pigment-based inks, it is difficult to achieve the same level as dye inks in terms of uniformity of solid image areas and color-developing properties of color images by adding ordinary hydrocarbon-based surfactants to the inks. Therefore, it has been already known that the use of the fluorine-based surfactant can reduce the surface tension of the ink, improve the uniformity of the solid image portion, and improve the color developability.

In addition, the ink used in such an ink jet recording system is required to have various characteristics in addition to the image quality. In particular, the ejection stability when ejecting ink from the head affects the image quality and is important.
For example, Patent Document 1 proposes that by adding a specific amount of a specific surfactant, it is possible to improve the ejection stability of the ink and cope with high-speed printing.

However, conventional inks have insufficient ink defoaming properties, and it is difficult to say that they are sufficient in terms of image quality.
An object of the present invention is to provide an ink having a high defoaming property and capable of improving the image quality.

The means for solving the above problems are as follows. That is,
<1> A fluorine-based surfactant (A) having an HLB value of more than 6, a diol-based surfactant (B) having an HLB value of 6 or less, and an HLB value of 6 or less and the surfactant ( An ink containing a surfactant (C) having a structure different from that of B).

According to the present invention, it is possible to provide an ink having a high defoaming property and capable of improving the image quality.

It is a diagram showing an example of a recording apparatus using the ink of the present invention. FIG. 3 is a perspective view of a main tank that stores the ink of the present invention. It is a schematic plan view showing an example of an ink container of the present invention. FIG. 2 is a schematic plan view including a case of the ink container of FIG. 1.

（一般式（２）中、Ｒ₁及びＲ₂は、それぞれ独立に、炭素数が３個以上６個以下のアルキル基であり、Ｒ₃及びＲ₄は、それぞれ独立に、メチル基又はエチル基であり、ｎは１以上６以下の整数である。）
＜５＞前記界面活性剤（Ｃ）が、下記一般式（３）で表される化合物である前記＜１＞から＜４＞のいずれかに記載のインク。

（一般式（３）中、Ｒは水素原子、または、炭素数が１個以上４個以下のアルキルラジカルである。ａは１以上３０以下の整数であり、ｂは０以上３０以下の整数である。ｘ及びｙは、４≦ｘ＋ｙ≦６０、ｘ≧ｙ、及びｙ≧１を満たす。）
＜６＞前記インクが、水と、色材と、有機溶剤とを含有する前記＜１＞から＜５＞のいずれかに記載のインク。
＜７＞前記フッ素系界面活性剤（Ａ）が、下記構造式（Ｉ）で表される基を有する化合物であり、
前記ジオール系界面活性剤（Ｂ）が、下記一般式（２）で表される化合物であり、
前記界面活性剤（Ｃ）が、下記一般式（３）で表される化合物であり、
前記インクが、水と、色材と、有機溶剤とを含有する前記＜１＞に記載のインク。
Ｃ₆Ｆ₁₃−ＣＨ₂ＣＨ₂− ・・・ （Ｉ）

（一般式（２）中、Ｒ₁及びＲ₂は、それぞれ独立に、炭素数が３個以上６個以下のアルキル基であり、Ｒ₃及びＲ₄は、それぞれ独立に、メチル基又はエチル基であり、ｎは１以上６以下の整数である。）

（一般式（３）中、Ｒは水素原子、または、炭素数が１個以上４個以下のアルキルラジカルである。ａは１以上３０以下の整数であり、ｂは０以上３０以下の整数である。ｘ及びｙは、４≦ｘ＋ｙ≦６０、ｘ≧ｙ、及びｙ≧１を満たす。）
＜８＞前記＜１＞から＜７＞のいずれかに記載のインクを容器中に収容したインク収容部を有するインク収容容器。
＜９＞前記＜１＞から＜７＞のいずれかに記載のインクを吐出させて画像を記録するインク吐出工程を含むインクジェット記録方法。
＜１０＞前記＜１＞から＜７＞のいずれかに記載のインクを吐出させて画像を記録するインク吐出手段を有するインクジェット記録装置。 Hereinafter, the present invention <1> will be described in detail. The following <2> to <10> are also included in the embodiment of the present invention <1>, and therefore these will also be described.
<2> The ink according to <1>, wherein the fluorine-based surfactant (A) is a compound having a group represented by the following structural formula (I).
_{C 6 F 13 -CH 2 CH 2} - ··· (I)
<3> The ink according to <1> or <2>, wherein the fluorine-based surfactant (A) is a compound represented by the following general formula (1).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· (1)
(In the general formula (1), n is an integer of 1 or more and 40 or less.)
<4> The ink according to any one of <1> to <3>, wherein the diol-based surfactant (B) is a compound represented by the following general formula (2).

(In the general formula (2), R ₁ and R ₂ are each independently an alkyl group having 3 to 6 carbon atoms, and R ₃ and R ₄ are each independently a methyl group or an ethyl group. And n is an integer of 1 or more and 6 or less.)
<5> The ink according to any one of <1> to <4>, wherein the surfactant (C) is a compound represented by the following general formula (3).

(In the general formula (3), R is a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a is an integer of 1 to 30 and b is an integer of 0 to 30. Yes, x and y satisfy 4≦x+y≦60, x≧y, and y≧1.)
<6> The ink according to any one of <1> to <5>, wherein the ink contains water, a coloring material, and an organic solvent.
<7> The fluorosurfactant (A) is a compound having a group represented by the following structural formula (I),
The diol-based surfactant (B) is a compound represented by the following general formula (2),
The surfactant (C) is a compound represented by the following general formula (3),
The ink according to <1>, wherein the ink contains water, a coloring material, and an organic solvent.
_{C 6 F 13 -CH 2 CH 2} - ··· (I)

(In the general formula (2), R ₁ and R ₂ are each independently an alkyl group having 3 to 6 carbon atoms, and R ₃ and R ₄ are each independently a methyl group or an ethyl group. And n is an integer of 1 or more and 6 or less.)

(In the general formula (3), R is a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a is an integer of 1 to 30 and b is an integer of 0 to 30. Yes, x and y satisfy 4≦x+y≦60, x≧y, and y≧1.)
<8> An ink container having an ink container containing the ink according to any one of <1> to <7>.
<9> An inkjet recording method including an ink ejection step of ejecting the ink according to any one of <1> to <7> to record an image.
<10> An inkjet recording apparatus having an ink ejecting unit that ejects the ink according to any one of <1> to <7> to record an image.

(ink)
The ink of the present invention comprises a fluorine-based surfactant (A) having an HLB value of more than 6, a diol-based surfactant (B) having an HLB value of 6 or less, and an HLB value of 6 or less and the above interface. A surfactant (C) having a structure different from that of the activator (B). In the present invention, the surfactant (C) having a structure different from that of the surfactant (B) may have a chemical structure different from that of the surfactant (B), and may be a diol-based surfactant. ..
Further, the case where the ink of the present invention is mainly used as an ink for inkjet recording will be described below as an example, but other image forming methods such as spray coating and roller coating can also be used.

The fluorinated surfactant is a surfactant in which H atom in the alkyl chain is replaced with F atom, and the fluorinated surfactant (A) is a compound having 2 to 16 carbon atoms which is fluorinated. A compound having 4 to 16 carbon atoms, which is fluorine-substituted, is more preferable.
Examples of the fluorinated surfactant (A) include perfluoroalkyl phosphate ester compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.

As the fluorine-based surfactant (A), a compound having a group represented by the following structural formula (I), a compound represented by the following general formula (F-2), and the like are preferably used.
_{C 6 F 13 -CH 2 CH 2} - ··· (I)
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y ··· (F-2)
In the compound represented by the above general formula (F-2), Y is H, or C _n F _2n+1 and n is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ -C _n F _{2n+. 1,} n is 4-6 integer, or p in C _p H _{2p + 1} is an integer of 1 to 19. a is an integer of 4-14.

The fluorosurfactant (A) is preferably a compound having a group represented by the following structural formula (I).
_{C 6 F 13 -CH 2 CH 2} - ··· (I)
Furthermore, the fluorine-based surfactant (A) is more preferably a compound represented by the following general formula (1).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· (1)
However, in the general formula (1), n is an integer of 1 or more and 40 or less.

（一般式（２）中、Ｒ₁及びＲ₂は、それぞれ独立に、炭素数が３個以上６個以下のアルキル基であり、Ｒ₃及びＲ₄は、それぞれ独立に、メチル基又はエチル基であり、ｎは１以上６以下の整数である。） Further, as the diol-based surfactant (B), compounds represented by the following general formula (2), acetylene glycol-based surfactants and the like are preferably used, and compounds represented by the following general formula (2) Is preferred.

(In the general formula (2), R ₁ and R ₂ are each independently an alkyl group having 3 to 6 carbon atoms, and R ₃ and R ₄ are each independently a methyl group or an ethyl group. And n is an integer of 1 or more and 6 or less.)

（一般式（３）中、Ｒは水素原子、または、炭素数が１個以上４個以下のアルキルラジカルである。ａは１以上３０以下の整数であり、ｂは０以上３０以下の整数である。ｘ及びｙは、４≦ｘ＋ｙ≦６０、ｘ≧ｙ、及びｙ≧１を満たす。） Further, the surfactant (C) is preferably a silicone-based surfactant, and more preferably a compound represented by the following general formula (3).

(In general formula (3), R is a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a is an integer of 1 to 30 and b is an integer of 0 to 30. Yes, x and y satisfy 4≦x+y≦60, x≧y, and y≧1.)

In the present invention, a fluorine-based surfactant (A) having an HLB value of more than 6, a diol-based surfactant (B) having an HLB value of 6 or less, and an HLB value of 6 or less and the surfactant By using together three types of surfactants (B) and three different surfactants (C) having different structures, it is possible to provide an ink capable of achieving both high defoaming property and image quality. Discharge instability caused by the tendency of a fluorine-based surfactant having an HLB value of greater than 6 to foam can be suppressed by the fact that two kinds of surfactants having an HLB value of 6 or less act as an antifoaming agent.
A surfactant having an HLB value of more than 6 has a stronger hydrophilic property, so that it becomes soluble in the solvent in the aqueous ink system. By including a fluorosurfactant (A) having an HLB value of more than 6 in the ink, the surface tension is lowered, and when printing on plain paper, the vehicle quickly penetrates into the paper and the colorant is applied to the surface. It is likely to remain and the image density becomes high. By using the compound having a group represented by the structural formula (I) as the fluorine-based surfactant (A), the uneven distribution of the colorant is eliminated, and the colorant is evenly present on the paper surface. The level dyeing property is remarkably improved. As a result, it is possible to obtain an image with high saturation and high color density, but with less show-through. Discharge instability due to the high foaming property, which is a characteristic of a fluorine-based surfactant, can be suppressed by adding two types of surfactants having an HLB value of 6 or less that function as an antifoaming agent.

<Compound Having Group Represented by Structural Formula (I)>
The compound having a group represented by the structural formula (I) can reduce the surface tension, improve the image quality (such as high color developability), and impart wettability to a member.
The compound having a group represented by the structural formula (I) is preferably a compound represented by the following general formula (1).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· (1)
In the general formula (1), n is preferably an integer of 1 or more and 40 or less, and more preferably an integer of 5 or more and 30 or less.
The perfluoroalkyl group C ₆ F ₁₃ in the general formula (1) is preferably a straight chain from the viewpoint of wettability to a member.
As the compound represented by the general formula (1), those appropriately synthesized may be used, or commercially available products may be used.
The compound represented by the general formula (1) is a compound in which n is 7 to 17 in the general formula (1); a compound in which n is 25 to 35 in the general formula (1); In the formula (1), n is 7 to 17 and 25 to 35; in the general formula (1), n is 5 to 20; in the general formula (1), n is 6 to 22 Some compounds may be mentioned. These may be used alone or in combination of two or more. Among these, in the general formula (1), n is 6 to 22, a compound in which n is 5 to 20 in the general formula (1), and n is 7 to 7 in the general formula (1). Particularly preferred are the compounds 17 and 25-35.
Examples of the commercially available product include Capstone (Capstone, registered trademark) FS-30 (n is 6 to 22 in the general formula (1)) and Capstone (Capstone, registered trademark) FS-34 manufactured by Chemours. (In the general formula (1), n is 5 to 20), Capstone (Capstone, registered trademark) FS-3100 (in the general formula (1), n is 7 to 17 and 25 to 35). .. These may be used alone or in combination of two or more.

The content of the fluorosurfactant (A) having an HLB value of more than 6 is not particularly limited and may be appropriately selected depending on the purpose, but is 0.04% by mass to the total amount of the ink. 1.5 mass% is preferable, 0.05 mass%-1 mass% is more preferable, 0.1 mass%-0.5 mass% is especially preferable. In this numerical range, the surface tension of the ink can be lowered, the vehicle can be quickly permeated, and the colorant can remain on the paper surface.
When the content is 0.04 mass% or more, the effect of high color development is obtained, and when the content is 1.5 mass% or less, good ink storage stability is obtained.

<Surfactant having an HLB value of 6 or less>
The two kinds of surfactants having an HLB value of 6 or less also behave as an antifoaming agent in the ink.
The surfactant added to the ink tends to be oriented at the liquid-gas interface of the ink, and the required function can be obtained by lowering the interfacial tension, but at the same time stabilizes the bubbles generated in the ink, It makes it difficult to defoam. To prevent this, an antifoaming agent is usually added.
Since the defoaming agent exerts the effect of breaking and suppressing bubbles by creating a non-uniform portion in the film of bubbles, if it is completely dissolved, the defoaming effect cannot be seen. For this reason, the HLB value of what is desired to act as an antifoaming agent must be 6 or less.

Here, the generation of bubbles (foaming) means that the liquid becomes a thin film and wraps air. Characteristics such as surface tension and viscosity of ink are involved in the generation of bubbles. That is, a liquid having a high surface tension, such as water, is difficult to foam because the force that tries to reduce the surface area of the liquid acts as much as possible. On the other hand, a high-viscosity, high-permeability ink easily foams because of its low surface tension, and the bubbles generated due to the viscosity of the solution are easily maintained, and it is difficult to defoam.
Usually, the defoaming agent locally lowers the surface tension of the foam film to destroy the foam, or disperses the foam by sprinkling an antifoaming agent that is hardly soluble in the foaming liquid on the surface of the foaming liquid. When a fluorosurfactant, which has an extremely strong function of reducing the surface tension, is used as the surfactant in the ink, the surface tension of the foam film can be locally reduced even if an antifoaming agent with the former mechanism is used. It is not normally used because it cannot be used. Therefore, the latter defoaming agent which is hardly soluble in the foaming liquid is used, but in this case, the stability of the ink may be lowered due to the defoaming agent which is poorly soluble in the solution.

In the present invention, in addition to a fluorine-based surfactant having an HLB value of 6 or more, a diol-based surfactant (B) having an HLB value of 6 or less, and the surfactant (B) having an HLB value of 6 or less. )) and a surfactant (C) having a different structure. Although the surfactants having an HLB value of 6 or less, particularly the compounds represented by the general formulas (2) and (3), which are added to the ink, have a function of lowering the surface tension not as strong as that of the fluorine-based surfactant, High compatibility with the fluorine-based surfactant. For this reason, the surfactant having an HLB value of 6 or less is efficiently taken into the foam film, and the surface of the foam film is locally localized due to the difference in surface tension between the fluorine-based surfactant and the surfactant having an HLB value of 6 or less. It is thought that the bubbles will break due to the imbalance.

Furthermore, as a result of intensive investigations by the present inventors, a diol-based surfactant (B) having an HLB value of 6 or less and an HLB value of 6 or less were used as compared with the case where a surfactant having an HLB value of 6 or less was used alone. It was found that by adding a surfactant (C) having a structure different from that of the above-mentioned surfactant (B) to the ink, an ink having more excellent defoaming property can be obtained.

The HLB value of the surfactant used in the present invention is a value for evaluating the hydrophilicity of the compound proposed by Griffin, and means the value calculated by the following mathematical formula (1). The HLB value by the Griffin method shows a value within the range of 0 to 20, and the larger the value is, the more hydrophilic the compound is.
HLB value=20×(mass% of hydrophilic group)
=20×(sum of formula weights of hydrophilic groups/molecular weight of surfactant)...Equation (1)

In the present invention, the surfactant having an HLB value of 6 or less preferably has an HLB value of 5 or less. When the HLB value is 6 or less, it is possible to suppress the generation of bubbles in the ink flow path during cleaning, and thus it is possible to reduce ejection defects of the ink composition due to the inclusion of bubbles.

The surfactant having an HLB value of 6 or less is not particularly limited, but specifically, Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, DF-110D, 82 (all trade names, manufactured by Air Products and Chemicals. Inc.), BYK-011, BYK-012, BYK-017, BYK-018, BYK-019, BYK-020, BYK-021, BYK-022, BYK-023, BYK-024, BYK-025, BYK-028, BYK-038, BYK-044, BYK-080A, BYK-093, BYK-094, BYK-1610, BYK-1615, BYK-1650, BYK-1. 1730 and BYK-1770 (all above are trade names, manufactured by Big Chemie Japan Co., Ltd.).

The diol-based surfactant (B) having an HLB value of 6 or less and the surfactant (C) having a structure different from that of the surfactant (B) are preferably the compound represented by the general formula (2) or The compound represented by General formula (3) is mentioned.

The compound represented by the general formula (2) is not particularly limited, but 2,4,7,9-tetramethyl-4,7-decanediol (HLB value=3.0), 2,5,8 , 11-tetramethyldodecane-5,8-diol (HLB value=2.6) and the like.

The content of the compound represented by the general formula (2) in the ink is usually 0.01 to 3% by mass, and preferably 0.1 to 2% by mass. When the content of the compound represented by the general formula (2) in the ink is 0.1% by mass or more, the filling property of the ink can be improved. On the other hand, when the content of the compound represented by the general formula (2) in the ink is 2% by mass or less, sufficient storage stability can be secured.

一般式（３）において、Ｒは、水素原子、又は、炭素数１個以上４個以下のアルキルラジカルを表す。ａは、１以上３０以下の整数を表し、ｂは０以上３０以下の整数を表す。ｘ及びｙは、４≦ｘ＋ｙ≦６０、ｘ≧ｙ、及びｙ≧１を満たす。 The surfactant (C) is preferably a compound represented by the general formula (3).

In the general formula (3), R represents a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a represents an integer of 1 or more and 30 or less, and b represents an integer of 0 or more and 30 or less. x and y satisfy 4≦x+y≦60, x≧y, and y≧1.

The alkyl radical represented by R is an alkyl radical having 1 to 4 carbon atoms which is radicalized by abstracting hydrogen in the alkyl group. That is, R represents an alkyl radical in which alkyl having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, and normal butyl is radicalized.

Specific examples of the surfactant represented by the general formula (3) and having an HLB value of 6 or less include the following compounds. However, the present invention is not limited to these.

The compound having an HLB value of 6 or less and represented by the general formula (3) is not particularly limited, but examples thereof include commercially available products such as BYK-017, BYK-018, BYK-019, BYK-021 and BYK. -023, BYK-024, BYK-025, BYK-028, BYK-044, BYK-093, BYK-094, BYK-1610, BYK-1615, BYK-1650, BYK-1730, BYK-1770, BYK-1798. (All manufactured by Big Chemie Japan), Silface SAG001, Silface SAG002, Silface SAG003, Silface SAG003, Silface SAG005, Silface SAG006, Silface SAG503A, Silface SAG008, Silface SAG009, Silface SAG010 ( Both are manufactured by Nissin Chemical Industry Co., Ltd.) and the like.

The content of the compound represented by the general formula (3) in the ink is usually 0.001 to 3% by mass, preferably 0.1 to 1.5% by mass. When the content of the compound represented by the general formula (3) in the ink is 0.1% by mass or more, the defoaming property of the ink can be improved. On the other hand, when the content of the compound represented by the general formula (3) in the ink is 1.5% by mass or less, sufficient storage stability can be secured.

There is no limitation on the addition of the defoaming agent other than those mentioned above, and examples thereof include a silicone defoaming agent, a polyether defoaming agent, and a fatty acid ester defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because of its excellent foam breaking effect.

The ink preferably further contains an organic solvent, water, and a coloring material, and may further contain other components as necessary.
The organic solvent is added for the purpose of preventing the ink from drying and improving the dispersion stability. Further, the organic solvent in the present invention includes those which are functionally classified as a penetrant, a foam suppressor and the like.
As the water, for example, deionized water, ultrafiltered water, reverse osmosis water, pure water such as distilled water, or ultrapure water can be used.
The components of these inks will be further described below.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , Nitrogen-containing heterocyclic compounds such as 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N- Amides such as dimethylpropionamide and 3-butoxy-N,N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. Etc.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also obtains good drying properties.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether and the like.

The polyol compound having 8 or more carbon atoms and the glycol ether compound can improve the ink permeability when paper is used as the recording medium.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the purpose. However, from the viewpoint of ink drying properties and ejection reliability, 10% by mass or more and 60% by mass or less is preferable, 20 mass% or more and 60 mass% or less are more preferable.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 90% by mass or less and 20% by mass or less from the viewpoint of the drying property of the ink and the ejection reliability. % To 60% by mass is more preferable.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. Also, a mixed crystal may be used.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, luster color pigments such as gold and silver, and metallic pigments.
As an inorganic pigment, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method. Can be used.
Further, as the organic pigment, an azo pigment, a polycyclic pigment (for example, a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofuraron pigment, etc.) , Dye chelates (for example, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, those having a good affinity with the solvent are preferably used. In addition, hollow resin particles and hollow inorganic particles can also be used.
Specific examples of the pigment include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (CI pigment black 11) for black. , Metal oxides such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104. , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B(Ca)), 48:3, 48:4, 49:1, 52: 2,53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, and the like.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used, and one kind may be used alone, or two or more kinds may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Dilectd Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or more, from the viewpoint of improvement of image density, good fixing property and ejection stability. It is as follows.

To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating the surface of the pigment with a resin to disperse, a method of dispersing using a dispersant, And so on.
Examples of a method for introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment include, for example, a self-dispersing pigment that is dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon). Can be used.
As a method for coating the surface of the pigment with a resin to disperse the pigment, a method in which the pigment is contained in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin-coated pigment. In this case, it is not necessary for all the pigments mixed in the ink to be coated with the resin, and as long as the effect of the present invention is not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. May be
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low molecular type dispersant or polymer type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant or the like can be used depending on the pigment.
Takemoto Yushi Co., Ltd. RT-100 (nonionic surfactant) and naphthalenesulfonic acid Na formalin condensate can also be suitably used as the dispersant.
The dispersants may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with the pigment. Further, it is also possible to manufacture an ink by mixing a pigment and other materials such as water and a dispersant to form a pigment dispersion and a material such as water and an organic solvent.
The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. A dispersion machine may be used for dispersion.
There is no particular limitation on the particle size of the pigment in the pigment dispersion, but since the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is high, the maximum frequency is 20 nm or more when converted to the maximum number. The thickness is preferably 500 nm or less, more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but it is preferably 0.1 mass% from the viewpoint of obtaining good ejection stability and increasing the image density. % Or more and 50% by mass or less is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, and butadiene resin. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, acrylic silicone resins and the like.
You may use the resin particle which consists of these resins. It is possible to obtain ink by mixing resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized appropriately may be used, or commercially available products may be used. These may be used alone or in combination of two or more kinds of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 nm or more and 1,000 nm or less from the viewpoint of obtaining good fixability and high image hardness. It is more preferably 200 nm or less and more preferably 10 nm or more and 100 nm or less.
The volume average particle diameter can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of fixability and storage stability of the ink, 1% by mass or more and 30% by mass or less based on the total amount of the ink. Is preferable and 5 mass% or more and 20 mass% or less are more preferable.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of maximum number is converted. Is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles and pigment particles. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additive>
An antiseptic/antifungal agent, an anticorrosive agent, a pH adjusting agent and the like may be added to the ink, if necessary.

<Antiseptic and fungicide>
The antiseptic/antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
The rust preventive agent is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and may be appropriately selected depending on the purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, from the viewpoint that the printing density and character quality are improved and good ejection properties are obtained, and the viscosity is preferably 5 mPa·s or more and 25 mPa·s or less. More preferable. Here, as the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. The measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN/m or less, and more preferably 32 mN/m or less at 25° C., from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member that comes into contact with the liquid.

<Recording medium>
The recording medium used for recording is not particularly limited, and examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.

<Recorded matter>
The ink recorded matter of the invention has an image formed by using the ink of the invention on a recording medium.
A recorded matter can be obtained by recording with an inkjet recording apparatus and an inkjet recording method.

<Ink container>
The ink container of the present invention is provided with an ink container in which the ink of the present invention is contained, and may further comprise other members appropriately selected according to need.
The shape, structure, size and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferable examples include those having at least an ink containing portion formed of an aluminum laminate film, a resin film or the like, for example, a main tank having an ink containing portion, an ink cartridge and the like.

One aspect of the ink container of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic plan view for explaining an example of the ink container of the present invention. FIG. 4 is a schematic plan view including the case (exterior) of the ink container of FIG.
As shown in FIG. 3, the ink containing container 200 is filled into the ink containing portion 241 from the ink filling port 242, and after being evacuated, the ink filling port 242 is closed by fusion. At the time of use, the ink discharge port 243 made of a rubber member is pierced with a needle of the apparatus main body and supplied to the apparatus. The ink containing portion 241 is formed of a packaging member such as an aluminum laminated film having no air permeability. As shown in FIG. 4, the ink containing portion 241 is usually contained in a plastic containing container case 244, and is detachably attached to various inkjet recording devices for use.

<Recording device, recording method>
The ink of the present invention can be suitably used for various recording devices using an inkjet recording method, such as a printer, a facsimile device, a copying device, a printer/fax/copier compound machine, and a three-dimensional modeling device.
In the present invention, the recording device and the recording method are a device capable of ejecting ink, various treatment liquids, and the like onto a recording medium, and a method of performing recording using the device. The recording medium means a medium to which ink or various treatment liquids can be attached even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means for feeding, conveying, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. ..
The recording device and the recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, but, for example, a warm air heater or an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording device and the recording method are not limited to those in which a significant image such as a character or a figure is visualized by ink. For example, it also includes one that forms a pattern such as a geometric pattern and one that models a three-dimensional image.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise limited.
Further, this recording device is not limited to a desktop type, and can be used as a wide recording device capable of printing on an A0 size recording medium, or for example, a continuous paper rolled into a roll as a recording medium. It also includes a continuous printer.
An example of the recording device will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism section 420 is provided inside the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packed with, for example, an aluminum laminate film. It is formed of a member. The ink container 411 is housed in a container case 414 made of plastics, for example. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus body is opened. The main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink discharge port 413 of the main tank 410 and the ejection head 434 for each color communicate with each other via the supply tube 436 for each color, and ink can be ejected from the ejection head 434 to the recording medium.

This recording device can include not only a portion for ejecting ink, but also a device called a pre-processing device, a post-processing device, or the like.
As one mode of the pretreatment device and the posttreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a pretreatment liquid and a posttreatment liquid are included. There is a mode in which a liquid container and a liquid discharge head are added and a pretreatment liquid and a posttreatment liquid are discharged by an inkjet recording method.
As another aspect of the pretreatment device and the posttreatment device, there is an aspect in which a pretreatment device and a posttreatment device other than the ink jet recording method are provided, for example, by a blade coating method, a roll coating method, a spray coating method.

The method of using the ink is not limited to the inkjet recording method, and can be widely used. In addition to the inkjet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

Examples of the present invention will be described below, but the present invention is not limited to the following examples. In the following, "part" means "part by mass" unless otherwise specified. "%" represents "mass %" unless otherwise specified.

(Production Example 1 of pigment dispersion)
-Preparation of cyan dispersion-
After thoroughly replacing the inside of a 1 L flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas introduction tube, a reflux tube and a dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (trade name: AS-6 manufactured by Toagosei Co., Ltd.) and 0.4 g of mercaptoethanol were charged, and the temperature was raised to 65°C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, styrene macromer (trade name: AS-6, manufactured by Toagosei Co., Ltd.). A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobisdimethylvaleronitrile 2.4 g and methyl ethyl ketone 18 g was added dropwise into the flask over 2.5 hours.
After the dropping was completed, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hour. After aging for 1 hour at 65° C., 0.8 g of azobisdimethylvaleronitrile was added and further aging for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added into the flask to obtain 800 g of a polymer solution having a concentration of 50% by mass.
Next, a part of the polymer solution was dried and measured by gel permeation chromatography (standard: polystyrene, solvent: tetrahydrofuran). As a result, the weight average molecular weight was 15,000.

28 g of the polymer solution, 26 g of Pigment Blue 15:3 (manufactured by Dainichiseika Kogyo Co., Ltd., Chromofine Blue A-220JC), 13.6 g of 1 mol/L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone and 30 g of ion-exchanged water are sufficiently stirred. did.
Then, the mixture was kneaded 20 times using a three-roll mill (manufactured by Noritake Company, trade name: NR-84A). The obtained paste was put into 200 g of ion-exchanged water, and after sufficiently stirring, methyl ethyl ketone and water were distilled off using an evaporator to obtain 160 g of a blue polymer fine particle dispersion having a solid content of 20.0% by mass. ..
When the obtained polymer fine particles were measured by Microtrac UPA (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50%) was 98 nm.

(Production Example 2 of pigment dispersion)
-Preparation of magenta dispersion-
Production of the pigment dispersion except that Pigment Blue 15:3, which is a copper phthalocyanine pigment, was changed to Pigment Red 122 (Dainichi Seika Kogyo Co., Ltd., Chromofine Magenta 6886) in Production Example 1 of the pigment dispersion. In the same manner as in Example 1, a reddish purple polymer particle dispersion was obtained.
When the obtained polymer fine particles were measured by Microtrac UPA (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50%) was 124 nm.

(Production Example 3 of pigment dispersion)
-Preparation of yellow dispersion-
Production Example 1 of the pigment dispersion, except that Pigment Blue 15:3, which is a copper phthalocyanine pigment, was changed to Pigment Yellow 74 (Fast Yellow 531 manufactured by Dainichi Seika Kogyo Co., Ltd.) in Production Example 1 of the pigment dispersion. In the same manner as in 1, a yellow polymer particle dispersion was obtained.
When the obtained polymer fine particles were measured by Microtrac UPA (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50%) was 78 nm.

(Production Example 4 of pigment dispersion)
-Preparation of black dispersion-
In the same manner as in Preparation Example 1 of the dispersion, except that Pigment Blue 15:3, which is a copper phthalocyanine pigment, was changed to Carbon Black (Degussa FW100) in Preparation Example 1 of the pigment dispersion. A fine polymer particle dispersion was obtained.
When the obtained polymer fine particles were measured by Microtrac UPA (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50%) was 110 nm.

Examples 1-14, Comparative Examples 1-8
(Ink preparation examples 1 to 22)
Using the pigment dispersions produced in Production Examples 1 to 4 of the pigment dispersions, inks of Ink Preparation Examples 1 to 22 were prepared by a conventional method according to the formulations shown in Tables 1 to 3 below, and the pH was 9 Was adjusted with a 10% aqueous solution of sodium hydroxide.
Specifically, a water-soluble organic solvent, a surfactant having an HLB value of more than 6, a surfactant having an HLB value of 6 or less, other additives, and ion-exchanged water are mixed in this order in the materials. After stirring for 30 minutes, the pigment dispersions obtained in Production Examples 1 to 4 of the pigment dispersion are added and stirred for 30 minutes, and then filtered through a membrane filter having a pore size of 0.8 μm to obtain Example 1 To 14 and Comparative Examples 1 to 8 (ink preparation examples 1 to 22) were obtained. It should be noted that the surfactant C-3 and the surfactant C-4 contain hydrophobic particles and are not filtered because the particles are collected by the filter when the particles are filtered. The presence or absence of filtration is also described in Tables 1 to 3. In addition, the unit of the numerical value in Tables 1-3 is "mass %."

The meanings of the abbreviations in Tables 1 to 3 are as follows.
・Surfactant A-1:
Fluorine-based surfactant (Capstone FS-34, manufactured by Chemours)
HLB value: 12
・Surfactant A-2:
Fluorine-based surfactant (Capstone FS-3100, manufactured by Chemours)
HLB value: 9.8
・Surfactant A-3:
Fluorosurfactant (Capstone FS-30, manufactured by Chemours)
HLB value: 11.0
・Surfactant A-4:
Fluorine-based surfactant (Unidyne DSN-403N,
The following fluorine compound and a mixture of polyethylene glycol _{C 6 F 13 -CH 2 CH (} OH) CH 2 -O- (CH 2 CH 2 O) a -H
_{C 6 F 13 -CH 2 CH (} OH) CH 2 -O- (CH 2 CH 2 O) a -CH 2 CH (OH) CH 2
- (CF _{2) 5} CF ₃
a: 8 to 9 on average
(Made by Daikin Industries, Ltd.)
HLB value: 12
-Surfactant B-1: 2,4,7,9-tetramethyl-4,7-decanediol HLB value=3.0
-Surfactant B-2: 2,5,8,11-tetramethyldodecane-5,8-diol HLB value=2.6
・Surfactant B-3:
Acetylene glycol-based surfactant (Surfynol 104E, manufactured by Air Products Japan, Inc., 50% by mass) HLB value=4
・Surfactant B-4:
Acetylene glycol-based surfactant (DF110D, manufactured by Air Products Japan, Inc., 32% by mass) HLB value=3
・Surfactant C-1:
Polyether-modified polydimethylsiloxane solution (BYK-1770,
Big Chemie Japan Co., Ltd., component 100 mass%) HLB value: 6 or less-Surfactant C-2:
Polyether-modified polydimethylsiloxane solution (BYK-019,
Big Chemie Japan Co., Ltd., component 100 mass%) HLB value: 6 or less-Surfactant C-3:
Mixture of foam-breaking polysiloxane, hydrophobic particles and polyglycol (BYK-028, manufactured by BYK Japan KK, 100% by mass of component)
HLB value: 6 or less-Surfactant C-4:
Mixture of foam-breaking polysiloxane, hydrophobic particles and polyglycol (BYK-093, manufactured by BYK Japan KK, 100% by mass of component)
HLB value: 6 or less-Surfactant C-5:
Polyoxyethylene (3) sodium tridecyl ether acetate (ECTD-3NEX, manufactured by Nikko Chemicals Co., Ltd.) HLB value: 6 or less-Surfactant D-1:
Polysiloxane-based surfactant (KF-351A, manufactured by Shin-Etsu Silicone Co., Ltd.)
HLB value = 12
・Surfactant D-2:
Polysiloxane-based surfactant (KF-643, manufactured by Shin-Etsu Silicone Co., Ltd.)
HLB value = 14
-Surfactant D-3:
Polysiloxane-based surfactant (L-7604, manufactured by Toray Dow Corning Co., Ltd.) HLB value=13
・Proxel LV: Antifungal agent (manufactured by Abyssia)

<Physical properties of ink>
The viscosity and static surface tension of each of the inks of Examples 1 to 14 and Comparative Examples 1 to 8 were measured as follows. The results are shown in Table 4.

-Viscosity-
The viscosity (mPa·s) of each ink at 25° C. was measured using an R-type viscometer (RC-500, manufactured by Toki Sangyo Co., Ltd.) at an appropriate rotation speed of 10 rpm or more and 100 rpm or less.

-Static surface tension-
The static surface tension (mN/m) of each ink at 25° C. was measured by a platinum plate method using a fully automatic surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

Next, various characteristics of each manufactured ink were evaluated as follows. The results are shown in Table 5. In addition, regarding the conditions shown below, the results are also shown by showing whether or not each ink satisfies the conditions, by showing "O" and "X", respectively.
Condition A: Fluorine-based surfactant (A) having an HLB value of more than 6 and HLB value of 6 or less
It contains all of a certain diol-based surfactant (B) and (C).
Condition B: The structure of the surfactant (A) has a group represented by the structural formula (I).
Condition C: The structure of the surfactant (A) is represented by the general formula (1).
Condition D: The structure of the surfactant (B) is represented by the general formula (2).
Condition E: The structure of the surfactant (C) is represented by the general formula (3).

<Defoaming properties>
In an environment of 25°C, put 10 ml of each ink prepared in a 100 ml graduated cylinder, inject air of a constant pressure until the volume of each ink and bubbles becomes 100 ml, and the time until all the bubbles disappear from there The defoaming time was used and evaluated according to the following criteria.
〔Evaluation criteria〕
AA: Defoaming time less than 60 seconds A: Defoaming time between 60 seconds and less than 180 seconds B: Foaming time between 180 seconds and less than 300 seconds C: Foaming time between 300 seconds and less than 600 seconds D: Foaming time Is over 600 seconds

<Discharge stability>
Printing is performed on my paper (manufactured by NBS Ricoh Co., Ltd.) using an inkjet printer (manufactured by Ricoh Co., Ltd., IPSIO GXe3300) in an environment adjusted to a temperature of 25° C.±0.5° C. and 50±5% RH. The printing pattern was a chart in which the printing area for each color was 5% of the total area of the paper surface, and 300 sheets of each of yellow, magenta, cyan, and black inks were continuously printed at 100% duty. The printing conditions were a recording density of 600 dpi and one-pass printing. After printing and drying the 300th sheet, the presence or absence of streaks in the solid portion of the 5% chart, white spots, and jet turbulence was visually observed and evaluated. The evaluation criteria at this time were as follows: A was passed and B and C were rejected.
〔Evaluation criteria〕
A: There are no streaks, white spots, or jet turbulence observed in solid areas.
B: Some streaks, white spots, and jet turbulence are observed in two or more solid areas.
C: Streaks, white spots, and jet turbulence are observed throughout the solid area.

<Image density>
Printing is performed on my paper (manufactured by NBS Ricoh Co., Ltd.) using an inkjet printer (manufactured by Ricoh Co., Ltd., IPSIO GXe3300) in an environment adjusted to a temperature of 25° C.±0.5° C. and 50±5% RH. The driving voltage of the piezo element was changed so that the ink ejection amount was evened, and the same amount of ink was attached to the recording medium. Each of the yellow, magenta, cyan, and black inks was printed at 100% duty. The printing conditions were a recording density of 300 dpi and one-pass printing.
After the print was dried, the solid image portions of black, yellow, magenta, and cyan were measured with a reflection-type color spectrophotometer (made by X-Rite) and judged according to the following criteria.
〔Evaluation criteria〕
AA: Black... 1.25 or more
Yellow・・・0.85 or more
Magenta...1.05 or more
Cyan: 1.05 or more A: Black: 1.20 or more and less than 1.25
Yellow: 0.80 or more and less than 0.85
Magenta...more than 1.00 and less than 1.05
Cyan: 1.00 or more and less than 1.05 B: Black: 1.15 or more and less than 1.20
Yellow: 0.75 or more and less than 0.80
Magenta... 0.95 or more and less than 1.00
Cyan: 0.95 or more and less than 1.00 C: Black: less than 1.15
Yellow・・・less than 0.75
Magenta...less than 0.95
Cyan: less than 0.95

(1) Evaluation of defoaming property: According to the comparison between Examples 1 to 14 and Comparative Examples 1 to 8, it is found that by satisfying the condition A, good defoaming property can be obtained.
(2) Evaluation of defoaming property: According to the comparison between Examples 1 to 10 and Examples 11 to 14, the condition A is satisfied, and in addition, the conditions B to E are satisfied. It can be seen that foaminess is obtained.
(3) Evaluation of defoaming property: According to the comparison between Examples 1 to 14 and Comparative Examples 5 to 7, if the surfactant having an HLB value larger than 6 is not a fluorine-based surfactant, the defoaming property is improved. You can see that you can not get the effect.
(4) Ejection stability evaluation: From the comparison between Examples 1 to 14 and Comparative Examples 1 to 8, it is understood that the ink having good defoaming property can obtain good ejection stability. This is because the minute air bubbles that are caught in the nozzle when ejecting the ink and the minute air bubbles that are generated in the ink due to the cavitation quickly disappear.
(5) Image Density: From the comparison between Examples 1 to 14 and Comparative Examples 1 to 7, it is understood that satisfactory image density can be obtained by satisfying the condition A.

400 image forming apparatus 401 exterior of image forming apparatus 401c cover of apparatus body 404 cartridge holder 410 main tank 410k, 410c, 410m, 410y for each color of black (K), cyan (C), magenta (M), and yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Ejection head 436 Supply tube

200 ink container 241 ink container 242 ink inlet 243 ink outlet 244 container case

JP, 2012-193268, A

Claims (10)

A fluorine-based surfactant (A) having an HLB value of greater than 6, a diol-based surfactant (B) having an HLB value of 6 or less, and a surfactant (B) having an HLB value of 6 or less. An ink containing a surfactant (C) having a different structure. The ink according to claim 1, wherein the fluorine-based surfactant (A) is a compound having a group represented by the following structural formula (I).
_{C 6 F 13 -CH 2 CH 2} - ··· (I) The ink according to claim 1, wherein the fluorine-based surfactant (A) is a compound represented by the following general formula (1).
_{C 6 F 13 -CH 2 CH 2} O (CH 2 CH 2 O) n H ··· (1)
(In the general formula (1), n is an integer of 1 or more and 40 or less.) The ink according to claim 1, wherein the diol-based surfactant (B) is a compound represented by the following general formula (2).

(In the general formula (2), R ₁ and R ₂ are each independently an alkyl group having 3 to 6 carbon atoms, and R ₃ and R ₄ are each independently a methyl group or an ethyl group. And n is an integer of 1 or more and 6 or less.) The ink according to any one of claims 1 to 4, wherein the surfactant (C) is a compound represented by the following general formula (3).

(In general formula (3), R is a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a is an integer of 1 to 30 and b is an integer of 0 to 30. Yes, x and y satisfy 4≦x+y≦60, x≧y, and y≧1.) The ink according to claim 1, wherein the ink contains water, a coloring material, and an organic solvent. The fluorine-based surfactant (A) is a compound having a group represented by the following structural formula (I),
The diol-based surfactant (B) is a compound represented by the following general formula (2),
The surfactant (C) is a compound represented by the following general formula (3),
The ink according to claim 1, wherein the ink contains water, a coloring material, and an organic solvent.
_{C 6 F 13 -CH 2 CH 2} - ··· (I)

(In the general formula (2), R ₁ and R ₂ are each independently an alkyl group having 3 to 6 carbon atoms, and R ₃ and R ₄ are each independently a methyl group or an ethyl group. And n is an integer of 1 or more and 6 or less.)

(In general formula (3), R is a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms. a is an integer of 1 to 30 and b is an integer of 0 to 30. Yes, x and y satisfy 4≦x+y≦60, x≧y, and y≧1.) An ink container having an ink container in which the ink according to claim 1 is contained. An ink jet recording method comprising an ink ejecting step of ejecting the ink according to claim 1 to record an image. An ink jet recording apparatus having an ink ejecting unit that ejects the ink according to claim 1 to record an image.

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