Ink composition, inkjet recording apparatus, inkjet recording method, and ink container

Abstract

To provide an ink composition excellent in dissolubility, an initial OD value and decoloration properties.SOLUTION: A first ink composition includes water, a water soluble organic solvent, and a color developer. The color developer includes a pH indicator, the water soluble organic solvent includes at least one water soluble organic solvent whose SP value is 16 or less and 11 or more, a blending amount of the water soluble organic solvent whose SP value is 16 or less and 11 or more, is 15 wt% or more. A second ink composition includes water, a water soluble organic solvent, and a color developer, and the color developer includes a pH indicator, the water soluble organic solvent includes at least one water soluble organic solvent whose SP value is 16 or less, and a blending amount of the water soluble organic solvent whose SP value is 16 or less, is 15 wt% or more, and the ink composition is an inkjet recording aqueous ink of the invention.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink composition, an inkjet recording apparatus, an inkjet recording method, and an ink container.

Background Art

[0002] Inks that disappear using pH indicators that develop color in an alkaline medium such as phenolphthalein and decolorize in a neutral medium are known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a solvent (humectant) for such an ink, glycerin is used. However, the pH indicator has poor solubility in glycerin, which causes clogging of the printer. In addition, due to poor solubility, there is a limit to the amount of pH indicator contained in the ink, and there is a problem that the initial OD value is low. When the pH indicator concentration is increased to improve the OD value, it is necessary to increase the amount of sodium hydroxide added to dissolve the pH indicator. Then, since the pH of the ink increases, it becomes difficult to decolorize, that is, there is a problem that it is difficult to achieve both the initial OD value and the decolorizing property.

[0005] Therefore, an object of the present invention is to provide an ink composition excellent in solubility, initial OD value, and decolorizing property.

Means for Solving the Problems

[0006] To achieve the above object, a first ink composition of the present invention contains water, a water-soluble organic solvent, and a color former, wherein the color former contains a pH indicator, The water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more. It is characterized in that the blending amount of the water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more is 15% by weight or more.

[0007] In order to achieve the above object, the second ink composition of the present invention contains water, a water-soluble organic solvent, and a color former, the color former contains a pH indicator, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less, and it is characterized in that the blending amount of the water-soluble organic solvent having an SP value of 16 or less is 15% by weight or more, and it is an aqueous ink for inkjet recording.

Effects of the Invention

[0008] The ink composition of the present invention is excellent in solubility, initial OD value, and decoloring property.

Brief Description of the Drawings

[0009]

Figure 1

Modes for Carrying Out the Invention

[0010] The ink composition of the present invention will be described. As described above, the first ink composition of the present invention contains water, a water-soluble organic solvent, and a color former, the color former contains a pH indicator, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more, and the blending amount of the water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more is 15% by weight or more. The second ink composition of the present invention contains water, a water-soluble organic solvent, and a color former as described above, the color former contains a pH indicator, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less, and the blending amount of the water-soluble organic solvent having an SP value of 16 or less is 15% by weight or more, and it is an aqueous ink for inkjet recording. In the present invention, the first ink composition and the second ink composition are collectively referred to as "the ink composition of the present invention" (hereinafter, sometimes referred to as "aqueous ink", "ink", or "decoloring ink").

[0011] The color former may contain, for example, a color former other than a pH indicator, or may not contain it, but it is preferable not to contain a color former other than a pH indicator. By the color former not containing a color former other than a pH indicator, for example, the decoloring property of the decoloring ink is improved, and it is possible to suppress the recorded content from being confirmed after decoloring.

[0012] The pH indicator is, for example, among reagents that change color depending on a change in the hydrogen ion concentration (pH change) in a solution, those that develop color in an alkaline state (for example, pH 9.8 to 13.4), the color fades as the pH shifts to the neutral side, and the color disappears (decolors) when the pH becomes neutral (for example, pH 8.5 or less). Specific examples of the pH indicator include at least one pH indicator selected from phenolphthalein, thymolphthalein, and o-cresolphthalein. The pH indicator may be used, for example, singly or in combination of two or more. In the ink composition of the present invention, the blending amount of the pH indicator is, for example, 0.1 to 3.0% by weight, preferably 0.1 to 0.8% by weight, and more preferably 0.2 to 0.8% by weight.

[0013] In the first ink composition of the present invention, as described above, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value (solubility parameter) of 16 or less and an SP value of 11 or more. Further, in the second ink composition of the present invention, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less as described above. The SP value is a value obtained by the following formula by, for example, the method of Fedors, and the unit is (cal / cm 3 ) 1 / 2 and is as follows. SP value = (ΣΔei / ΣΔvi) 1 / 2 Δei: Evaporation energy of atoms and atomic groups (cal / mol) Δvi: Molar volume (cm 3 / mol)

[0014] The water-soluble organic solvent with an SP value of 16 or less and 11 or more in the first ink composition of the present invention can be a conventionally known water-soluble organic solvent as long as it has an SP value of 16 or less and 11 or more. For example, among a wetting agent for preventing ink drying at the nozzle tip of an inkjet head and a penetrant for adjusting the drying rate on a recording medium, those with an SP value of 16 or less and 11 or more can be used. Specific examples of the water-soluble organic solvent with an SP value of 16 or less and 11 or more include, for example, methanol (SP value: 14.5 - 14.8), ethanol (SP value: 12.7), isopropanol (SP value: 11.5), n-butanol (SP value: 11.3), polyethylene glycol with a molecular weight of 200 (SP value: 12.0), diethylene glycol (SP value: 14.6), propylene glycol (SP value: 13.5), triethylene glycol (SP value: 13.6), tripropylene glycol (SP value: 11.5), 1,2-hexanediol (SP value: 11.8), 2-pyrrolidone (SP value: 11.4), etc. It is preferable to contain at least one of triethylene glycol or polyethylene glycol with a molecular weight of 200. The water-soluble organic solvent with an SP value of 16 or less and 11 or more may be used alone or in combination of two or more. In the latter case, for example, with respect to the total weight of the ink composition of the present invention, the total blending amount of two or more water-soluble organic solvents with an SP value of 16 or less and 11 or more is 15% by weight or more. In the water-soluble organic solvent with an SP value of 16 or less and 11 or more, the lower limit of the SP value is not particularly limited, and examples include an SP value of 11 or more, an SP value of 12 or more, and an SP value of 13 or more. When the SP value of the water-soluble organic solvent with an SP value of 16 or less and 11 or more is 11 or more, for example, compared with the case where the SP value is less than 11, the time until the decoloring ink decolors (decoloring time) becomes longer, which is preferable. The preferable decoloring time is, for example, 6 hours or more and 72 hours or less. In this case, for example, a printed matter printed using the decoloring ink of the present invention can have the printed content visually recognized on the day of printing, but will decolor and become unrecognizable after several days. Therefore, the first ink composition of the present invention enables, for example, secure printing.

[0015] The water-soluble organic solvent with an SP value of 16 or less in the second ink composition of the present invention can be a conventionally known water-soluble organic solvent as long as it has an SP value of 16 or less. For example, among wetting agents that prevent drying of the ink at the nozzle tip of an inkjet head and penetrants that adjust the drying rate on a recording medium, those with an SP value of 16 or less can be used. Specific examples of the water-soluble organic solvent with an SP value of 16 or less include methanol (SP value: 14.5 - 14.8), ethanol (SP value: 12.7), isopropanol (SP value: 11.5), n-butanol (SP value: 11.3), polyethylene glycol with a molecular weight of 200 or more and an SP value of 16 or less (e.g., polyethylene glycol with a molecular weight of 200 (SP value: 12.0)), diethylene glycol (SP value: 14.6), propylene glycol (SP value: 13.5), triethylene glycol (SP value: 13.6), polypropylene glycol with an SP value of 16 or less, tripropylene glycol (SP value: 11.5), 1,2-hexanediol (SP value: 11.8), propylene glycol monomethyl ether (SP value: 10.2), triethylene glycol monobutyl ether (SP value: 10.3), triethylene glycol - n-butyl ether (SP value: 9.8), tripropylene glycol - n-butyl ether (SP value: 9.2), 2-pyrrolidone (SP value: 11.4), etc. The water-soluble organic solvent with an SP value of 16 or less preferably contains, for example, a diol-type polyalkylene glycol. The water-soluble organic solvent with an SP value of 16 or less may be used alone or in combination of two or more. In the latter case, for example, with respect to the total weight of the ink composition of the present invention, the total blending amount of two or more water-soluble organic solvents with an SP value of 16 or less is 15% by weight or more.

[0016] The water-soluble organic solvent may or may not contain other water-soluble organic solvents in addition to, for example, the water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more, or the water-soluble organic solvent having an SP value of 16 or less. Examples of the other water-soluble organic solvents include wetting agents for preventing drying of the ink at the nozzle tip of the inkjet head and penetrants for adjusting the drying rate on the recording medium. The SP value of the other water-soluble organic solvent is not particularly limited, and may be, for example, 16 or less or 16 or more. However, from the viewpoint of the solubility of the pH indicator contained in the color former, it is preferably free of other water-soluble organic solvents having an SP value exceeding 16.

[0017] The wetting agent is not particularly limited. Examples thereof include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ketoalcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethers such as polyalkylene glycol; polyhydric alcohols such as alkylene glycol, glycerin, trimethylolpropane, and tri methylol ethane; 2-pyrrolidone; N-methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone and the like. Examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol. Examples of the alkylene glycol include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, thiodiglycol, and hexylene glycol. These wetting agents may be used alone or in combination of two or more.

[0018] The blending amount of the wetting agent with respect to the total amount of the ink composition is, for example, 0% by weight to 84.9% by weight, preferably 0% by weight to 20% by weight, and more preferably 0% by weight to 2% by weight.

[0019] Examples of the penetration agent include glycol ethers. Examples of the glycol ethers include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether, and tripropylene glycol-n-butyl ether. The penetration agent may be used alone or in combination of two or more.

[0020] The compounding amount of the penetration agent relative to the total amount of the ink composition is, for example, 0 wt% to 84.9 wt%, preferably 0 wt% to 20 wt%, and more preferably 0 wt% to 2 wt%.

[0021] The ink composition of the present invention may contain, for example, a pH adjuster. Examples of the pH adjuster include alkali metal hydroxides, alkali metal carbonates, hydroxides of Group 2 to Group 12 elements, carbonates of Group 2 to Group 12 elements, amines, and the like. Specific examples of the pH adjuster include, for example, sodium hydrogen carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, sodium carbonate, triethanolamine, N-butyldiethanolamine, sodium citrate (disodium citrate, trisodium citrate), sodium hydrogen carbonate, potassium phosphate (potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate), trisodium phosphate, sodium hydrogen phosphate (disodium hydrogen phosphate, sodium dihydrogen phosphate), sodium dihydrogen pyrophosphate, and the like. Among these, sodium hydrogen carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, sodium carbonate, triethanolamine, and N-butyldiethanolamine are preferred. The pH adjuster may be used alone or in combination of two or more. In the ink composition of the present invention, the blending amount of the pH adjuster is 5% by weight or less, preferably 3% by weight or less.

[0022] The water is preferably ion-exchanged water or pure water. The blending amount (water ratio) of the water with respect to the total amount of the ink composition is appropriately determined according to desired ink properties and the like. The water ratio may be, for example, the balance of the other components. The blending amount of the water is, for example, 60% to 90% by weight, 65% to 85% by weight, or 70% to 85% by weight.

[0023] The ink composition may further contain, if necessary, a conventionally known additive. Examples of the additive include surfactants, viscosity adjusters, surface tension adjusters, antifungal agents, and the like. Examples of the viscosity adjuster include polyvinyl alcohol, cellulose, water-soluble resins, and the like.

[0024] The ink composition of the present invention can be used, for example, but not limited to, for inkjet recording. The ink composition of the present invention can also be used, for example, in writing instruments such as pens, markers, and brushes; paints; and other applications.

[0025] Next, an ink storage container of the present invention is an ink storage container containing ink, characterized in that the ink is the ink composition of the present invention. Examples of the ink storage container include ink cartridges, tanks, pouches, and the like. As the main body of the ink storage container, for example, conventionally known ones can be used.

[0026] Next, an inkjet recording apparatus and an inkjet recording method of the present invention will be described.

[0027] The inkjet recording apparatus of the present invention includes a flow path and an ink ejection means, and is an inkjet recording apparatus that ejects the ink supplied to the flow path by the ink ejection means, characterized in that the ink composition of the present invention is supplied to the flow path.

[0028] FIG. 1 shows a configuration example of an inkjet recording apparatus of the present invention. As shown in the figure, this inkjet recording apparatus 1 includes an ink cartridge 2, an ink ejection means (inkjet head) 3, a head unit 4, a carriage 5, a drive unit 6, a platen roller 7, and a purge device 8 as main components. Although not shown, the ink cartridge 2 and the ink ejection means 3 are connected by a flow path, and the ink composition of the present invention is supplied from the ink cartridge 2 containing the ink composition of the present invention to the flow path, and the ink ejection means 3 ejects the ink composition of the present invention onto a recording medium.

[0029] The ink cartridge 2 contains, for example, the ink composition of the present invention. As the main body of the ink cartridge, for example, conventionally known ones can be used.

[0030] Also, although not shown, the inkjet recording apparatus 1 may include, in addition to the ink cartridge 2 containing the ink composition of the present invention, a set of four ink cartridges each containing one of four colors of aqueous ink: yellow, magenta, cyan, and black. Further, instead of the set of the four ink cartridges, an integrated ink cartridge whose interior is partitioned so as to form an aqueous yellow ink storage section, an aqueous magenta ink storage section, an aqueous cyan ink storage section, and an aqueous black ink storage section may be used.

[0031] The inkjet head 3 installed in the head unit 4 performs recording on a recording medium (for example, recording paper) P. The carriage 5 mounts the ink cartridge 2 and the head unit 4. The drive unit 6 reciprocates the carriage 5 in a linear direction. As the drive unit 6, for example, a conventionally well-known one can be used (see, for example, Japanese Patent Application Laid-Open No. 2008-246821). The platen roller 7 extends in the reciprocating direction of the carriage 5 and is disposed facing the inkjet head 3.

[0032] The purge device 8 sucks defective ink containing bubbles or the like accumulated inside the inkjet head 3. As the purge device 8, for example, a conventionally well-known one can be used (see, for example, Japanese Patent Application Laid-Open No. 2008-246821).

[0033] On the platen roller 7 side of the purge device 8, a wiper member 20 is disposed adjacent to the purge device 8. The wiper member 20 is formed in a spatula shape and wipes the nozzle forming surface of the inkjet head 3 as the carriage 5 moves. In FIG. 1, the cap 18 covers a plurality of nozzles of the inkjet head 3 that is returned to the reset position when recording is completed in order to prevent the ink from drying.

[0034] In the inkjet recording apparatus 1 of this example, the ink cartridge 2 is mounted on one carriage 5 together with the head unit 4. However, the present invention is not limited to this. In the inkjet recording apparatus 1, the ink cartridge 2 may be mounted on a carriage different from the head unit 4. Further, the ink cartridge 2 may not be mounted on the carriage 5 and may be disposed and fixed within the inkjet recording apparatus 1. In these modes, for example, the ink cartridge 2 and the head unit 4 mounted on the carriage 5 are connected by the flow path such as a tube, and the ink is supplied from the ink cartridge 2 to the head unit 4. Further, in these modes, instead of the ink cartridge 2, a bottle-shaped ink bottle may be used. In this case, it is preferable that the ink bottle is provided with an injection port for injecting ink from the outside to the inside.

[0035] The inkjet recording using this inkjet recording apparatus 1 is carried out, for example, as follows. First, the recording paper P is fed from a paper feed cassette (not shown) provided on the side or below the inkjet recording apparatus 1. The recording paper P is introduced between the inkjet head 3 and the platen roller 7. Predetermined recording is performed on the introduced recording paper P with aqueous ink ejected from the inkjet head 3. The recorded recording paper P is discharged from the inkjet recording apparatus 1. In FIG. 1, the illustration of the paper feed mechanism and the paper discharge mechanism of the recording paper P is omitted.

[0036] The apparatus shown in FIG. 1 employs a serial type inkjet head, but the present invention is not limited to this. The inkjet recording apparatus may be an apparatus that employs a line type inkjet head or a roll-to-roll.

[0037] Next, the inkjet recording method of the present invention is an inkjet recording method in which ink is ejected onto a recording medium by an inkjet method for recording, and the ink composition of the present invention is used as the ink. The inkjet recording method of the present invention can be implemented, for example, using the inkjet recording apparatus of the present invention. The recording includes printing, printing pictures, printing, etc.

Examples

[0038] Next, the examples of the present invention will be described together with comparative examples. Note that the present invention is not limited and restricted by the following examples and comparative examples.

[0039] (Preparation of decoloring ink) Each component of the decoloring ink composition shown in Table 1 below was uniformly mixed to obtain the decoloring inks of Examples 1 to 13. Further, each component of the decoloring ink composition shown in Table 2 below was uniformly mixed to obtain the decoloring inks of Comparative Examples 1 to 5. In Tables 1 and 2, the numerical values in parentheses indicate the SP values of the respective components. Then, the solubility of the color former in the decoloring inks of Examples 1 to 13 and Comparative Examples 1 to 5 was evaluated. Further, the decoloring inks of Examples 1 to 13 and Comparative Examples 1 to 5 were applied to recording paper (trade name: Asクル Super White Plus, Asクル Co., Ltd.), and the initial OD value, visibility on the same day, and decoloring property were confirmed by the method shown below. Tables 1 and 2 below show the test results of each decoloring ink together.

[0040]

Table 1

[0041]

Table 2

[0042] (Solubility) The solubility of each decoloring ink was evaluated based on the following criteria after mixing each component. A: Completely dissolved. B: Precipitates occur after stirring and standing at room temperature for one month. C: Sediment is observed immediately after stirring.

[0043] (Initial OD value) The initial OD value (optical density) was measured immediately after applying each decoloring ink using a SpectroEye (registered trademark) spectrophotometer manufactured by X-Rite Inc. (light source: D50, viewing angle: 2°, ANSI-T), and evaluated based on the following criteria. A: Achieves formula (1), or OD value of 0.40 or more B: Achieves formula (1), or OD value of 0.25 or more C: Cannot achieve formula (1), and OD value is 0.25 or less Formula (1) y > 0.75x + 0.05 x: Amount of pH indicator in the ink y: OD value

[0044] (Visibility on the same day) The visibility on the same day was evaluated based on the following criteria by measuring the OD value after leaving each ink recorded on the recording medium for 6 hours. A: OD value difference from white paper is 0.10 or more B: OD value difference from white paper is less than 0.10

[0045] (Decolorability) The decolorability was evaluated based on the following criteria by measuring the OD value after leaving each ink recorded on the recording medium for 72 hours (3 days). A: OD value difference from white paper is less than 0.03 B: OD value difference from white paper is less than 0.10 C: OD value difference from white paper is 0.10 or more

[0046] As shown in Tables 1 and 2 above, for the decolorizing inks of Examples 1 to 13, the evaluations of solubility, initial OD value, and decolorizing property were all A or B, indicating good results. Furthermore, for Examples 1 to 12, the evaluations of same-day visibility were all A, indicating good results. Therefore, from the perspective of achieving both same-day visibility and decolorizing property, it was suggested that in the decolorizing ink of the present invention, the SP value of the water-soluble organic solvent is preferably 16 or less and 11 or more. In contrast, for the decolorizing inks of Comparative Examples 1 to 3 and 5, the evaluations of solubility were all poor at C, and precipitates were observed immediately after stirring. Also, for the decolorizing ink of Comparative Example 4, the evaluations of initial OD and same-day visibility were poor at C, and it was unclear.

Industrial Applicability

[0047] As described above, the aqueous ink of the present invention is excellent in solubility, initial OD value, and decolorizing property. The use of the aqueous ink of the present invention can be widely applied to recording on various recording media.

Explanation of Reference Numerals

[0048] 1 Inkjet recording apparatus 2 Ink cartridge 3 Ink ejection means (inkjet head) 4 Head unit 5 Carriage 6 Drive unit 7 Platen roller 8 Purge device

Claims

1. An ink composition comprising water, a water-soluble organic solvent, and a color former, wherein the color former is only a pH indicator, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more, and the blending amount of the water-soluble organic solvent having an SP value of 16 or less and an SP value of 11 or more is 15% by weight or more.

2. An ink composition comprising water, a water-soluble organic solvent, and a color former, wherein the color former is only a pH indicator, the water-soluble organic solvent contains at least one water-soluble organic solvent having an SP value of 16 or less, and the blending amount of the water-soluble organic solvent having an SP value of 16 or less is 15% by weight or more, and the ink composition is an aqueous ink for inkjet recording.

3. The ink composition according to claim 2, wherein the water-soluble organic solvent having an SP value of 16 or less contains a diol-type polyalkylene glycol.

4. The ink composition according to claim 2 or 3, wherein the blending amount of the water-soluble organic solvent having an SP value of 16 or less is 18% by weight or more.

5. The ink composition according to any one of claims 1 to 4, wherein the pH indicator contains at least one selected from phenolphthalein, thymolphthalein, and o-cresolphthalein.

6. The ink composition according to any one of claims 1 to 5, wherein the blending amount of the pH indicator is 0.1 to 3.0% by weight.

7. The ink composition according to any one of claims 1 to 6, wherein the blending amount of the pH indicator is 0.1 to 0.8% by weight.

8. The ink composition according to any one of claims 1 to 7, wherein the blending amount of the pH indicator is 0.2 to 0.8% by weight.

9. Furthermore, it contains a pH adjuster, and the blending amount of the pH adjuster is 5% by weight or less. The ink composition according to any one of claims 1 to 8.

10. The ink composition according to claim 9, wherein the blending amount of the pH adjuster is 3% by weight or less.

11. An inkjet recording apparatus including a flow path and an ink ejection means, wherein the inkjet recording apparatus ejects the ink supplied to the flow path onto a recording medium by the ink ejection means, and the ink composition according to any one of claims 1 to 10 is supplied to the flow path.

12. A recording step including ejecting ink onto a recording medium by an inkjet method for recording. An inkjet recording method, characterized in that, in the recording step, the ink composition according to any one of claims 1 to 10 is used as the ink.

13. An ink storage container containing ink, wherein the ink is the ink composition according to any one of claims 1 to 10.

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