Water-based ink for inkjet recording and inkjet recording device

Abstract

This technology reduces environmental impact while also improving the stability of colorants. [Solution] The water-based ink for inkjet recording contains gardenia yellow pigment, a water-soluble organic solvent, cyclodextrins, and water. The cyclodextrins contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25°C.

Description

Technical Field

[0001] This specification discloses a technology related to an aqueous ink for inkjet recording and an inkjet recording apparatus.

Background Art

[0002] Patent Document 1 discloses an aqueous inkjet ink composition that can reduce environmental impact by using bio-derived materials.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, a bio-derived coloring material is used as the coloring agent. However, bio-derived coloring materials are easily decomposed and the color development stability over time is not sufficient. This specification provides a technology that can achieve reduction of environmental impact and improvement of the stability of the coloring agent.

Means for Solving the Problems

[0005] The aqueous ink for inkjet recording disclosed in this specification contains gardenia yellow pigment, a water-soluble organic solvent, cyclodextrins, and water. The cyclodextrins contain 7 or more glucose molecules and have a solubility in water at 25°C of 30 g / 100 mL or more.

[0006] This water-based inkjet recording ink uses gardenia yellow pigment as a colorant, thus reducing its environmental impact compared to inks that use petroleum-derived dyes. Furthermore, this water-based inkjet recording ink contains cyclodextrins. Cyclodextrins are compounds that form cyclic structures, and can encapsulate other molecular species in the cavities formed within them. In this water-based inkjet recording ink, the cyclodextrins contain seven or more glucose molecules. Therefore, the cyclodextrins form cavities of appropriate size, allowing for the encapsulation of gardenia yellow pigment. This suppresses the decomposition of gardenia yellow pigment due to light, heat, etc. Additionally, because cyclodextrins have relatively high water solubility, the cyclodextrins encapsulating gardenia yellow pigment can dissolve suitably and stably in the water-based ink. This enables high stability of the colorant.

[0007] Furthermore, an inkjet recording device is also novel and useful. The inkjet recording device comprises an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section, and ejects the aqueous inkjet recording ink from the ink ejection section. The aqueous inkjet recording ink contains gardenia yellow pigment, a water-soluble organic solvent, cyclodextrins, and water. The cyclodextrins contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25 °C. [Brief explanation of the drawing]

[0008] [Figure 1] This shows the configuration of an inkjet recording device. [Modes for carrying out the invention]

[0009] (Configuration of the inkjet recording device 10) The inkjet recording device 10 of the embodiment (hereinafter sometimes referred to as "recording device 10") will be described with reference to the drawings. The recording device 10 is a device that, according to the inkjet recording method, ejects water-based inkjet recording ink (hereinafter sometimes referred to as "water-based ink") toward a recording medium P (for example, recording paper) and records an image on the recording medium P. The recording device 10 is used by being placed on a table. However, in other embodiments, the recording device 10 may be used by being placed on the floor or on a rack.

[0010] As shown in Figure 1, the recording device 10 comprises four ink cartridges 2, an inkjet head 3, a head unit 4, a carriage 5, a drive unit 6, and a platen roller 7 as its main components.

[0011] The four ink cartridges 2 each contain one of four water-based inks: yellow, magenta, cyan, and black. While this embodiment shows a set of four ink cartridges 2, a modified version may use an integrated ink cartridge with its interior partitioned to form separate sections for water-based yellow ink, water-based magenta ink, water-based cyan ink, and water-based black ink. Conventional ink cartridge bodies can be used.

[0012] The inkjet head 3 is installed in the head unit 4. The inkjet head 3 records images onto the recording medium P. The four ink cartridges 2 and the head unit 4 are mounted on the carriage 5. The drive unit 6 moves the carriage 5 back and forth in a linear direction. For example, a conventionally known drive unit 6 can be used. The platen roller 7 extends in the reciprocating direction of the carriage 5 and is positioned opposite the inkjet head 3.

[0013] The inkjet head 3 is configured, for example, as multiple layers of thin metal plates stacked on top of each other. Each plate has a through-hole formed in it. The stacking of multiple plates with through-holes forms a channel for the water-based ink to flow through. Each plate is bonded together, for example, with an adhesive.

[0014] In the recording device 10 of this embodiment, the four ink cartridges 2 are mounted on a single carriage 5 together with the head unit 4. However, each of the four ink cartridges 2 may be mounted on a carriage separate from the head unit 4. Alternatively, each of the four ink cartridges 2 may not be mounted on the carriage 5, but instead be arranged and fixed within the recording device 10. In these embodiments, for example, each of the four ink cartridges 2 and the head unit 4 mounted on the carriage 5 are connected by a tube or the like, and water-based ink is supplied from each of the four ink cartridges 2 to the head unit 4. In these embodiments, instead of the four ink cartridges 2, four bottle-shaped ink bottles may be used. In this case, each ink bottle may be provided with an inlet for injecting ink from the outside into the inside.

[0015] Inkjet recording using this recording device 10 is performed, for example, as follows: First, recording paper P is fed from a paper feed cassette (not shown) located to the side or below the recording device 10. The recording paper P is introduced between the inkjet head 3 and the platen roller 7. A predetermined image is recorded on the introduced recording paper P by water-based ink ejected from the inkjet head 3. The recording paper P, on which the image has been recorded, is ejected from the recording device 10. Note that the paper feeding mechanism and paper ejection mechanism for the recording paper P are omitted from Figure 1.

[0016] Although the recording device 10 shown in Figure 1 employs a serial inkjet head, the recording device 10 may also employ a line inkjet head, roll-to-roll, or the like.

[0017] (Water-based ink for inkjet recording) The water-based inkjet recording ink disclosed herein is used as yellow among four colors: yellow, magenta, cyan, and black. Known inks can be used for magenta, cyan, and black as appropriate. The water-based yellow ink will be described in detail below.

[0018] (Details of the yellow water-based ink) The yellow water-based ink contains a colorant, a water-soluble organic solvent, cyclodextrins, and water. The colorant, water-soluble organic solvent, and cyclodextrins are dissolved or dispersed in water.

[0019] (Colorants) The colorant is of biological origin, specifically gardenia yellow pigment. "Biological origin" means derived from plants or animals, and includes not only components directly obtained from plants or animals, but also derivatives of components directly obtained from plants or animals. While substances derived from fossil fuels such as petroleum could arguably be considered biological if their origins are traced back, in this specification, substances derived from fossil fuels are not included in the definition of biological origin.

[0020] The amount of gardenia yellow pigment relative to the total amount of yellow aqueous ink is not particularly limited. The lower limit of the amount is, for example, 0.1% by mass or more, 0.5% by mass or more, 1.0% by mass or more, and 2.0% by mass or more. The upper limit of the amount is, for example, 20.0% by mass or less, 15.0% by mass or less, 10.0% by mass or less, and 5.0% by mass or less. The range of the amount can be set by appropriately combining the upper and lower limits mentioned above, for example, 0.1% by mass or more and 20.0% by mass or less, for example, 0.5% by mass or more and 15.0% by mass or less, for example, 1.0% by mass or more and 10.0% by mass or less, and for example, 2.0% by mass or more and 5.0% by mass or less. High stability can be achieved if the amount of gardenia yellow pigment is within the above range.

[0021] (Water-soluble organic solvent) The water-soluble organic solvent is not particularly limited, and any solvent can be used as long as it has the property of dissolving in water. Examples of the water-soluble organic solvent include glycerin, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol, thiodiglycol, etc. Further, glycol ethers having a propylene oxide group are included. Other examples of the water-soluble organic solvent include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, etc. Further, lower alkyl ethers of alkylene glycols such as ethylene glycol monomethyl (or ethyl, propyl, butyl) ether, diethylene glycol monomethyl (or ethyl, propyl, butyl) ether, triethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, tetraethylene glycol monomethyl (or ethyl, propyl, butyl, hexyl) ether, propylene glycol monomethyl (or ethyl, propyl, butyl) ether, dipropylene glycol monomethyl (or ethyl, propyl, butyl) ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl (or ethyl, propyl, butyl) ether, tetrapropylene glycol monomethyl (or ethyl) ether, etc. are included. Further, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc. are included. Among these, from the viewpoint of further reducing the environmental load, a bio-derived water-soluble organic solvent is preferable, and for example, glycerin is preferable.

[0022] The content of the water-soluble organic solvent relative to the total amount of the yellow aqueous ink is not particularly limited. The lower limit of the content is, for example, 1.0% by mass or more, and for example, 3.0% by mass or more, and for example, 5.0% by mass or more, and for example, 10.0% by mass or more. The upper limit of the content is, for example, 30.0% by mass or less, and for example, 25.0% by mass or less, and for example, 20.0% by mass or less, and for example, 15.0% by mass or less. The range of the content can be set by appropriately combining the above-mentioned upper and lower limits. For example, it is 1.0% by mass or more and 30.0% by mass or less, and for example, 3.0% by mass or more and 25.0% by mass or less, and for example, 5.0% by mass or more and 20.0% by mass or less, and for example, 10.0% by mass or more and 15.0% by mass or less.

[0023] (Cyclodextrins) Cyclodextrins are compounds derived from organisms and are formulated to suppress the decomposition of gardenia yellow pigment. Cyclodextrins are compounds in which a plurality of glucose molecules are bonded by glycosidic bonds to form a cyclic structure. Cyclodextrins have a cavity inside the cyclic structure and can include other molecular species whose shapes and dimensions are compatible within the cavity. By including gardenia yellow pigment in cyclodextrins, the gardenia yellow pigment can be stabilized and the decomposition of the gardenia yellow pigment by light, heat, etc. can be suppressed.

[0024] The present cyclodextrins contain 7 or more glucose molecules. That is, cyclodextrins containing 6 or fewer glucose molecules (for example, α-cyclodextrin (6 glucose molecules)) are not included in the present cyclodextrins. It is considered that cyclodextrins can form an appropriate cavity (inner diameter of about 0.6 nm or more) for including gardenia yellow pigment by containing 7 or more glucose molecules.

[0025] These cyclodextrins have relatively high water solubility. Specifically, these cyclodextrins have a solubility in water of 30 g / 100 mL or more at 25°C. This allows the cyclodextrins to dissolve suitably in aqueous ink while encapsulating gardenia yellow pigment. Generally, cyclodextrins (β-cyclodextrin, γ-cyclodextrin, etc.) have a solubility in water of less than 30 g / 100 mL at 25°C. Therefore, in order to improve water solubility, the hydroxyl groups of these cyclodextrins are substituted with other groups. The substituent is not particularly limited, but for example, it is a hydroxypropyl group. In this case, for example, the hydroxyl groups at positions 2, 3, and 6 of the glucose skeleton of the cyclodextrin are randomly substituted with hydroxypropyl groups. When the substituent is a hydroxypropyl group, the average degree of substitution is not particularly limited, but for example, it is between 2 and 12, or between 4 and 10, or between 6 and 8. Furthermore, any substituent and average degree of substitution can be used as long as their solubility in water satisfies the above-mentioned values.

[0026] As mentioned above, cyclodextrins are not particularly limited as long as they contain seven or more glucose molecules and satisfy the solubility requirements in water described above. Examples of cyclodextrins include hydroxypropyl-β-cyclodextrin and hydroxypropyl-γ-cyclodextrin.

[0027] (water) The water is preferably deionized water or pure water. The water content relative to the total amount of yellow aqueous ink is appropriately determined according to the desired ink characteristics, etc. The water content is, for example, in the range of 15.0% by mass or more and 95.0% by mass or less, or in the range of 25.0% by mass or more and 85.0% by mass or less. The water content may, for example, be the remainder of the other components.

[0028] (Other ingredients) The yellow water-based ink may further contain a surfactant. The surfactant is not particularly limited and can be appropriately selected depending on the purpose; for example, commercially available products may be used. Specifically, examples of surfactants include silicone-based surfactants and acetylene-based surfactants. In particular, since silicone-based surfactants do not contain impurities such as ethylene oxide, using a silicone-based surfactant as the surfactant can further reduce the generation of VOCs (Volatile Organic Compounds).

[0029] Examples of commercially available silicone-based surfactants include "Sylface® SAG002," "Sylface® SAG005," and "Sylface® SAG503A," all manufactured by Nisshin Chemical Industry Co., Ltd.

[0030] Examples of commercially available acetylene-based surfactants include "Orphin® E1004," "Orphin® E1008," and "Orphin® E1010" manufactured by Nisshin Chemical Industry Co., Ltd.; "Surfinol® 440," "Surfinol® 465," and "Surfinol® 485" manufactured by Air Products and Chemicals Inc.; and "Acetylenel® E40" and "Acetylenel® E100" manufactured by Kawaken Fine Chemicals Co., Ltd.

[0031] The yellow water-based ink may contain other surfactants in addition to / benefiting silicone-based surfactants and acetylene-based surfactants. Examples of other surfactants include the nonionic surfactants "EMULGEN®" series, "RHEODOL®" series, "EMASOL®" series, "EXCEL®" series, "EMANON®" series, "AMIET®" series and "AMINON®" series manufactured by Kao Corporation; the nonionic surfactant "SOLBO®" series manufactured by Toho Chemical Industry Co., Ltd.; and the nonionic surfactants "DOBANOX®" series and "LEOCOL®" series manufactured by Lion Corporation. "LEOX (registered trademark)" series, "LAOL, LEOCOL (registered trademark)" series, "LIONOL (registered trademark)" series, "CADENAX (registered trademark)" series, "LIONON (registered trademark)" series and "LEOFAT (registered trademark)" series, etc.; Clariant's nonionic surfactants "Genapol" series, "Genagen" series, etc.; Kao Corporation's anionic surfactants "EMAL (registered trademark)" series, "LATEMUL (registered trademark)" series, "VENOL (registered trademark)" series, "NEOPELEX (registered trademark)" series, NS Examples include SOAP, KS SOAP, OS SOAP, and the "PELEX®" series; anionic surfactants manufactured by Lion Corporation, such as the "LIPOLAN®" series, "LIPON®" series, "SUNNOL®" series, "LIPOTAC® TE,ENAGICOL" series, "LIPAL®" series, and "LOTAT®" series; and cationic surfactants manufactured by Daiichi Kogyo Seiyaku Co., Ltd., such as "Kachiogen® ES-OW" and "Kachiogen® ES-L". Among the surfactants mentioned above, from the viewpoint of further reducing the environmental impact, bio-derived surfactants are preferred, for example, the "Genapol" series and the "Genagen" series.

[0032] A single surfactant may be used alone, or two or more surfactants may be used in combination. The amount of surfactant relative to the total amount of yellow water-based ink can be appropriately selected depending on the purpose. For example, the amount may be 0.1% to 5% by mass, 0.5% to 3.5% by mass, or 1% to 3% by mass.

[0033] The yellow water-based ink may further contain conventionally known additives as needed. Examples of additives include pH adjusters, viscosity modifiers, surface tension modifiers, and antifungal agents. Examples of viscosity modifiers include polyvinyl alcohol, cellulose, and water-soluble resins.

[0034] A yellow water-based ink can be prepared, for example, by uniformly mixing a colorant, a water-soluble organic solvent, cyclodextrins, water, and other additives as needed, using a conventionally known method, and then removing insoluble materials using a filter or the like. [Examples]

[0035] Next, the yellow aqueous ink disclosed herein will be described in detail by examples and comparative examples. However, the technology disclosed herein is not limited in any way to these examples.

[0036] (Preparation of yellow water-based ink) Aqueous inks for each example and comparative example were prepared by mixing the components shown in Tables 1 and 2. The numerical values ​​in the columns for each component in each table indicate the content of that component relative to the total amount of each aqueous ink, and the unit is mass%.

[0037] [Table 1]

[0038] [Table 2]

[0039] The color development stability over time, ink application, and ink uniformity of each prepared aqueous ink were evaluated according to the method described below.

[0040] (Evaluation of the long-term stability of color development) Five g of each prepared aqueous ink was weighed into a glass bottle and stored in a 60°C constant temperature bath for three days. The aqueous inks before and after storage were each diluted 1000 times with pure water, and their absorbance was measured. The peak top values ​​of the absorbance spectra obtained from the aqueous inks before and after storage were extracted, and the rate of change from the value before storage to the value after storage was calculated. The temporal stability of the color development was evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2. Note that for Comparative Examples 3-5 and 7, separation occurred when the components were mixed, making it impossible to measure the absorbance, and therefore the temporal stability of the color development was not evaluated. The same applies to the evaluation of the ink's introduceability described later. A: Absorbance change rate is less than 25% B: Absorbance change rate is 25% or more but less than 35% C: Absorbance change rate is 35% or more

[0041] (Evaluation of ink flow) For each prepared water-based ink, a suction operation was performed twice to fill the inkjet head with yellow water-based ink. Afterward, a nozzle check pattern was printed on plain paper. Based on the nozzle check pattern printed on the plain paper, the number of normal channels ejected correctly from the nozzles was counted, and the ratio of normal channels to the total number of channels was calculated. Ink inlet performance was then evaluated according to the following criteria. The evaluation results are shown in Tables 1 and 2. A: Discharged from all nozzles B: Discharged from nozzles with a capacity of 95% or more C: Dispensed from a nozzle with less than 95% efficiency.

[0042] (Evaluation of ink uniformity) Each prepared aqueous ink was mixed using a magnetic stirrer for at least 15 minutes. The uniformity of the mixed aqueous ink was evaluated visually according to the following criteria. The evaluation results are shown in Tables 1 and 2. A: No separation C: Separation available

[0043] As shown in Tables 1 and 2, Examples 1 to 10 showed excellent color development stability over time.

[0044] In contrast, Comparative Example 1 does not contain component (A) (i.e., the cyclodextrins in question). Therefore, it is thought that the gardenia yellow pigment decomposed and faded when exposed to heat, light, etc., resulting in a significant decrease in absorbance and thus poor long-term stability of the color development.

[0045] Furthermore, in Comparative Example 2, hydroxypropyl-α-cyclodextrin is contained as component (a) instead of component (A). Hydroxypropyl-α-cyclodextrin has a cyclic structure in which six glucose molecules are bonded together. Therefore, compared to component (A), the cavity inside the cyclic structure is smaller, and it is thought that the gardenia yellow pigment could not be encapsulated within this cavity, resulting in the decomposition of the gardenia yellow pigment when exposed to heat, light, etc.

[0046] Furthermore, in Comparative Examples 3 to 5, component (a) contains α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, respectively, instead of component (A). Since these compounds are not hydroxypropylated, their water solubility is lower compared to component (A) (α-cyclodextrin: approximately 13 g / 100 mL at 25°C, β-cyclodextrin: approximately 1.9 g / 100 mL at 25°C, γ-cyclodextrin: approximately 26 g / 100 mL at 25°C). Therefore, it is thought that these cyclodextrins did not dissolve in the aqueous ink, resulting in separation. From these results, it can be seen that cyclodextrins function suitably as yellow aqueous inks because they have a certain degree of high water solubility.

[0047] Furthermore, in Comparative Example 6, glucose is included as component (a) instead of component (A). Since glucose is a monosaccharide, the inclusion effect described above was not obtained in Comparative Example 6, and it is thought that the gardenia yellow pigment decomposed when exposed to heat, light, etc.

[0048] Comparative Example 7 contains hydroxypropyl cellulose as component (a) instead of component (A). Since hydroxypropyl cellulose is a chain-like polymer, it does not exhibit the inclusion effect described above. Furthermore, because hydroxypropyl cellulose has a large molecular weight, when the same amount as in Example 3, 18.0% by mass, is added, the hydroxypropyl cellulose gels without dissolving in the aqueous ink. For this reason, it is thought that it did not function as a yellow aqueous ink.

[0049] Furthermore, comparing the examples, Examples 1-5 are similar except for the difference in the content of hydroxypropyl-β-cyclodextrin. Similarly, Examples 6-10 are similar except for the difference in the content of hydroxypropyl-γ-cyclodextrin. As shown in Examples 1-5 and 6-10, a higher content of cyclodextrins improves the long-term stability of the color development. This is thought to be because there are relatively more cavities for encapsulating the gardenia yellow pigment, making it easier for the gardenia yellow pigment to be encapsulated. On the other hand, it was found that a relatively high content of component (A) can reduce the ink's introduceability. This is thought to be because cyclodextrins are bulky, and various interactions are at work between them. When introducing aqueous ink into an inkjet head, the aqueous ink flows through a narrow channel. Therefore, if the aqueous ink contains a large amount of cyclodextrins, the above interactions become larger, and the fluidity may decrease locally. As a result, the ink's introduceability is thought to have decreased.

[0050] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above.

[0051] Furthermore, the technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness.

[0052] Even if, in the claims of this patent application, each claim depends on only some of the claims, it is not limited to the claim being dependent only on those specific claims. To the extent that it is not technically contradictory, each claim may be dependent on other claims that were not dependent at the time of application. That is, the technologies of each claim can be combined in various ways as follows: (Item 1) Gardenia yellow pigment, Water-soluble organic solvents, Cyclodextrins and Water and, The cyclodextrins described above contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25°C. Water-based ink for inkjet recording. (Item 2) The water-based inkjet recording ink according to item 1, wherein the content of the cyclodextrins is 3.0% by mass or more and 21% by mass or less based on the total amount of the water-based inkjet recording ink. (Item 3) The aforementioned cyclodextrins include hydroxypropyl-β-cyclodextrin, The water-based inkjet recording ink according to item 2, wherein the content of hydroxypropyl-β-cyclodextrin is 5.0% by mass or more and 21% by mass or less based on the total amount of the water-based inkjet recording ink. (Item 4) The water-based inkjet recording ink according to item 3, wherein the content of hydroxypropyl-β-cyclodextrin is 8.0% by mass or more and 18% by mass or less based on the total amount of the water-based inkjet recording ink. (Item 5) The aforementioned cyclodextrins include hydroxypropyl-γ-cyclodextrin, The water-based inkjet recording ink according to item 2, wherein the content of hydroxypropyl-γ-cyclodextrin is 3.0% by mass or more and 20% by mass or less based on the total amount of the water-based inkjet recording ink. (Item 6) The water-based inkjet recording ink according to item 5, wherein the content of hydroxypropyl-γ-cyclodextrin is 4.0% by mass or more and 16% by mass or less based on the total amount of the water-based inkjet recording ink. (Item 7) An inkjet recording apparatus comprising an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section, wherein the aqueous inkjet recording ink is ejected from the ink ejection section, The aforementioned water-based inkjet recording ink is Gardenia yellow pigment, Water-soluble organic solvents, Cyclodextrins and Water and, The cyclodextrins described above contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25°C. Inkjet recording device. [Explanation of symbols]

[0053] 2: Ink cartridge, 3: Inkjet head, 4: Head unit, 5: Carriage, 6: Drive unit, 7: Platen roller, 10: Inkjet recording device

Claims

1. Gardenia yellow pigment, Water-soluble organic solvents, Cyclodextrins and Water and, The cyclodextrins described above contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25°C. Water-based ink for inkjet recording.

2. The water-based inkjet recording ink according to claim 1, wherein the content of the cyclodextrins is 3.0% by mass or more and 21% by mass or less with respect to the total amount of the water-based inkjet recording ink.

3. The aforementioned cyclodextrins include hydroxypropyl-β-cyclodextrin, The water-based inkjet recording ink according to claim 2, wherein the content of the hydroxypropyl-β-cyclodextrin is 5.0% by mass or more and 21% by mass or less with respect to the total amount of the water-based inkjet recording ink.

4. The water-based inkjet recording ink according to claim 3, wherein the content of the hydroxypropyl-β-cyclodextrin is 8.0% by mass or more and 18% by mass or less based on the total amount of the water-based inkjet recording ink.

5. The aforementioned cyclodextrins include hydroxypropyl-γ-cyclodextrin, The water-based inkjet recording ink according to claim 2, wherein the content of the hydroxypropyl-γ-cyclodextrin is 3.0% by mass or more and 20% by mass or less with respect to the total amount of the water-based inkjet recording ink.

6. The water-based inkjet recording ink according to claim 5, wherein the content of the hydroxypropyl-γ-cyclodextrin is 4.0% by mass or more and 16% by mass or less with respect to the total amount of the water-based inkjet recording ink.

7. An inkjet recording apparatus comprising an ink storage section, an ink ejection section, and an aqueous inkjet recording ink stored in the ink storage section, wherein the aqueous inkjet recording ink is ejected from the ink ejection section, The aforementioned water-based inkjet recording ink is Gardenia yellow pigment, Water-soluble organic solvents, Cyclodextrins and Water and, The cyclodextrins described above contain seven or more glucose molecules and have a solubility in water of 30 g / 100 mL or more at 25°C. Inkjet recording device.

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