Water-based ink for ink-jet recording

Abstract

To provide an inkjet recording water-based ink capable of achieving wide color reproduction region over magenta to red and excellent in magenta chroma and recording concentration.SOLUTION: An inkjet recording water-based ink includes quinacridone pigment, azo pigment and water, The quinacridone pigment includes a solid solution including C.I. pigment red 202 and C.I. pigment violet 19; the azo pigment includes C.I. pigment red 146; and the mass ratio of the content (Q) of the quinacridone pigment in the total amount to the content (A) of the azo pigment is Q:A=9:1-2:8.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a water-based ink for ink-jet recording. [Background technology]

[0002] It has been known in the past to use a solid solution containing two or more pigments in a water-based ink for ink-jet recording to improve the characteristics (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-150515 A Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, in inkjet recording, reddish coloring is important from the viewpoint of visibility. Although it is possible to achieve the reddish coloring by improving the red ink, it is preferable to achieve it by improving the magenta ink, which is one of the three primary colors of yellow, magenta, and cyan.

[0005] However, even if a target color is reproduced using a solid solution containing two or more pigments, problems such as a narrow color reproduction range and a decrease in saturation in the mixed color portion tend to occur. For this reason, there is a high demand for a wide color reproduction range from magenta (hue angle of about -40°) to red (hue angle of about 40°), and there is also a demand for improvements in magenta saturation and recording density.

[0006] Therefore, an object of the present invention is to provide a water-based ink for ink-jet recording that can achieve a wide color reproduction range from magenta to red and also has good magenta chroma and recording density. [Means for solving the problem]

[0007] In order to achieve the above object, the water-based ink for ink-jet recording of the present invention comprises: A quinacridone pigment, an azo pigment, and water, The quinacridone pigment comprises a solid solution comprising CI Pigment Red 202 and CI Pigment Violet 19; The azo pigment comprises CI Pigment Red 146, a mass ratio of the total content (Q) of the quinacridone pigment to the total content (A) of the azo pigment is Q:A=9:1 to 2:8; It is characterized by: Effect of the Invention

[0008] The water-based ink for ink-jet recording of the present invention uses a solid solution containing CI Pigment Red 202 and CI Pigment Violet 19 in combination with CI Pigment Red 146, and has a mass ratio of the content (Q) of the quinacridone pigment to the content (A) of the azo pigment in the total amount of the water-based ink of Q:A=9:1 to 2:8, thereby making it possible to achieve a wide color reproduction range from magenta to red, and also providing good magenta chroma and recording density. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a graph illustrating the synergistic effect of the present invention. [Diagram 2] FIG. 2 is a schematic perspective view showing the configuration of an example of the inkjet recording apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the present invention, chroma (C * ) is, for example, the L * a * b * Color system (CIE1976(L) * a * b * ) color system) based on a * and b* It is calculated by the following formula (see JIS Z 8729). C * ={(a *2 )+(b *2 )} 1 / 2

[0011] In the present invention, the "hue angle" refers to, for example, * , b * L expressed on a plane * a * b * It represents an angle on the color system chromaticity diagram and is defined as follows: a * ≧0, b * ≧0 (first quadrant), hue angle = tan -1 (b * / a * ) a * ≦0, b * ≧0 (second quadrant), hue angle = 180° + tan -1 (b * / a * ) a * ≦0, b * ≦0 (third quadrant), hue angle = 180° + tan -1 (b * / a * ) a * ≧0, b * ≦0 (fourth quadrant), hue angle = 360° + tan -1 (b * / a * )

[0012] The water-based ink for ink-jet recording (hereinafter, may be referred to as "water-based ink" or "ink") of the present invention will be described. The water-based ink of the present invention contains a quinacridone pigment, an azo pigment, and water.

[0013] The quinacridone pigment includes a solid solution containing CI Pigment Red 202 (hereinafter sometimes referred to as "PR202") and CI Pigment Violet 19 (hereinafter sometimes referred to as "PV19"). In the present invention, the "solid solution" refers to a pigment that exists as a mixed crystal (a state in which the molecules of two or more pigments are crystallized in a mixed state) and is different from a simple mixture of two or more pigments. The solid solution is sufficient as long as it is a quinacridone pigment that contains at least PR202 and PV19, and may or may not contain a quinacridone pigment other than PR202 and PV19 (hereinafter referred to as "other pigments"). When the solid solution contains the other pigments, the content ratio of the other pigments in the total amount of the solid solution is, for example, less than the content of the solid solution in the total amount of the aqueous ink and the content of CI Pigment Red 146 in the total amount of the aqueous ink. The content of the other pigment in the total amount of the solid solution is, for example, less than 0.3 mass % and 0.1 mass % or less.

[0014] The content (Q) of the quinacridone pigment in the total amount of the water-based ink is, for example, 0.5% by mass to 10% by mass, 1% by mass to 9% by mass, or 1% by mass to 7% by mass.

[0015] The quinacridone pigment contained in the aqueous ink may be only a solid solution containing PR202 and PV 19. The aqueous ink may further contain a quinacridone pigment other than the solid solution containing PR202 and PV 19 in addition to the solid solution containing PR202 and PV 19. In the aqueous ink, the mass ratio of the solid solution containing PR202 and PV 19 to the total amount of the quinacridone pigment is, for example, 50 mass% or more, 70 mass% or more, or 100 mass%.

[0016] The azo pigment includes CI Pigment Red 146 (hereinafter, sometimes referred to as "PR146").

[0017] The content (A) of the azo pigment in the aqueous ink is, for example, 0.5% to 10% by mass, 0.5% to 8% by mass, or 0.5% to 6% by mass.

[0018] The azo pigment contained in the aqueous ink may be only PR 146. Furthermore, the aqueous ink may further contain an azo pigment other than PR 146 in addition to PR 146. In the aqueous ink, the mass proportion of PR 146 to the total amount of azo pigments is, for example, 50 mass% or more, 70 mass% or more, or 100 mass%.

[0019] The mass ratio of the quinacridone pigment content (Q) to the azo pigment content (A) in the total amount of the water-based ink is Q:A=9:1 to 2:8. The mass ratio of the quinacridone pigment content (Q) to the azo pigment content (A) in the total amount of the water-based ink may be, for example, Q:A=7:3 to 4:6.

[0020] The aqueous ink uses a solid solution containing PR202 and PV19 in combination with PR146, and the mass ratio of the content (Q) of the quinacridone pigment to the content (A) of the azo pigment in the total amount of the aqueous ink is set to Q:A=9:1 to 2:8, thereby achieving a wide color reproduction range from magenta to red, and also providing good magenta chroma and recording density. The wide color reproduction range exceeds the arithmetic mean intermediate level between the solid solution containing PR202 and PV19 and PR146. As shown in FIG. 1, the arithmetic mean intermediate level is on a straight line connecting the plot of Comparative Example 1, which uses a solid solution of PR202 and PV19 alone, and the plot of Comparative Example 2, which uses PR146 alone. In contrast, in Examples 1 to 17, which use a solid solution of PR202 and PV19 in combination with PR146, * and b * exceeded the line, indicating a synergistic effect. * and b * was standardized by the International Commission on Illumination (CIE) in 1976. * a * b*Color system (CIE1976(L) * a * b * ) color specification system (see JIS Z 8729).

[0021] The sum (Q+A) of the quinacridone pigment content (Q) and the azo pigment content (A) in the total amount of the water-based ink is, for example, 5% by mass to 9% by mass, 5% by mass to 8% by mass, 6% by mass to 8% by mass, or 6% by mass to 9% by mass.

[0022] If the total (Q+A) is 5% by mass to 9% by mass, it is possible to obtain a water-based ink with a better balance of hue angle, magenta chroma, and recording density.

[0023] When the mass ratio Q:A is 7:3 to 4:6 and the total (Q+A) is 5% by mass to 8% by mass, it is possible to obtain a water-based ink having an excellent balance of hue angle, magenta saturation, and recording density.

[0024] When the mass ratio Q:A is 7:3 to 4:6 and the total (Q+A) is 6% by mass to 8% by mass, it is possible to obtain a water-based ink that not only has an excellent balance of hue angle, magenta saturation, and recording density, but also has particularly excellent recording density.

[0025] When the mass ratio is Q:A=7:3 to 5:5 and the total (Q+A) is 6% by mass to 9% by mass, it is possible to obtain a water-based ink that not only has an excellent balance of hue angle, magenta saturation, and recording density, but also has particularly excellent recording density.

[0026] The water-based ink may further contain, in addition to the quinacridone pigment and the azo pigment, a pigment and a dye other than the quinacridone pigment and the azo pigment.

[0027] Pigments that can be used in the water-based ink include the quinacridone pigments and azo pigments, and include CI Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123, 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 221, 222, 224, and 238; CI Pigment Violet 19 and 196; CI Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 73, 74, 75, 78, 83, 93, 94, 95, 97, 98, 114, 128, 129, 138, 150, 151, 154, 180, 185 and 194; CI Pigment Orange 31 and 43; and the like. Among these, quinacridone pigments and azo pigments are preferable.

[0028] The aqueous ink may be prepared by dispersing a pigment in water using a dispersant. As the dispersant, for example, a general polymer dispersant (pigment dispersion resin) or the like may be used. The pigment may be a self-dispersing pigment. The self-dispersing pigment is, for example, a pigment particle to which at least one hydrophilic group such as a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, or the like and a salt thereof is introduced by chemical bonding directly or via another group, and thus the pigment can be dispersed in water without using a dispersant.

[0029] The water is preferably ion-exchanged water or pure water. The content of the water in the total amount of the water-based ink is, for example, 10% by mass to 90% by mass, or 20% by mass to 80% by mass. The content of the water may be, for example, the remainder of other components.

[0030] The water-based ink may further contain a surfactant, such as an acetylene glycol surfactant.

[0031] The acetylene glycol surfactant may be, for example, a commercially available product. Examples of the commercially available product include "Olfine (registered trademark) E1004", "Olfine (registered trademark) E1008" and "Olfine (registered trademark) E1010" manufactured by Nissin Chemical Industry Co., Ltd.; "Surfynol (registered trademark) 440", "Surfynol (registered trademark) 465" and "Surfynol (registered trademark) 485" manufactured by Air Products and Chemicals Co., Ltd.; "Acetylenol (registered trademark) E40" and "Acetylenol (registered trademark) E100" manufactured by Kawaken Fine Chemical Co., Ltd.; and the like.

[0032] The aqueous ink may contain other surfactants in addition to or in place of the acetylene glycol surfactant. Examples of the other surfactants include nonionic surfactants "EMULGEN (registered trademark)" series, "RHEODOL (registered trademark)" series, "EMASOL (registered trademark)" series, "EXCEL (registered trademark)" series, "EMANON (registered trademark)" series, "AMIET (registered trademark)" series, and "AMINON (registered trademark)" series manufactured by Kao Corporation; nonionic surfactants "SORBON (registered trademark)" series manufactured by Toho Chemical Industry Co., Ltd.; nonionic surfactants "DOBANOX (registered trademark)" series, "LEOCOL (registered trademark)" series, "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 manufactured by Lion Corporation; anionic surfactants "EMAL (registered trademark)" series, "LATEMUL (registered trademark)" series, "VENOL (registered trademark)" series, "NEOPELEX (registered trademark)" series, NS SOAP, KS SOAP, OS Examples include SOAP and the "PELEX (registered trademark)" series; anionic surfactants manufactured by Lion Corporation, such as the "LIPOLAN (registered trademark)" series, the "LIPON (registered trademark)" series, the "SUNNOL (registered trademark)" series, the "LIPOTAC (registered trademark) TE, ENAGICOL" series, the "LIPAL (registered trademark)" series, and the "LOTAT (registered trademark)" series; and cationic surfactants manufactured by Daiichi Kogyo Seiyaku Co., Ltd., such as "Kachiogen (registered trademark) ES-OW" and "Kachiogen (registered trademark) ES-L". The surfactants may be used alone or in combination of two or more kinds.

[0033] The content ratio of the surfactant is, for example, 4 parts by mass or more with respect to 100 parts by mass of the total of the content of the quinacridone pigment and the content of the azo pigment.

[0034] The aqueous ink may further contain a water-soluble organic solvent, such as a wetting agent that prevents the ink from drying at the nozzle tip of the inkjet head and a penetrant that adjusts the drying speed on the recording medium.

[0035] The wetting agent is not particularly limited, and 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 glycols; polyhydric alcohols such as alkylene glycols, glycerin, trimethylolpropane, and trimethylolethane; 2-pyrrolidone; N-methyl-2-pyrrolidone; and 1,3-dimethyl-2-imidazolidinone. 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. Among these, polyhydric alcohols such as alkylene glycols and glycerin are preferred.

[0036] The content of the humectant in the total amount of the water-based ink is, for example, 0% by mass to 95% by mass, 5% by mass to 80% by mass, or 5% by mass to 50% by mass.

[0037] Examples of the penetrating agent include glycol ether. Examples of the glycol ether 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, trimethylene 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 penetrating agent may be used alone or in combination of two or more.

[0038] The content of the penetrant in the total amount of the water-based ink is, for example, 0% by mass to 20% by mass, 0% by mass to 15% by mass, or 1% by mass to 6% by mass.

[0039] The water-based ink may further contain conventionally known additives as necessary. Examples of the additives include a pH adjuster, a viscosity adjuster, a surface tension adjuster, a mildewproofing agent, and a glossy paper fixing agent. Examples of the viscosity adjuster include polyvinyl alcohol, cellulose, and a water-soluble resin.

[0040] The aqueous ink can be prepared, for example, by uniformly mixing the quinacridone pigment, the azo pigment, water, and, if necessary, other additive components, using a conventionally known method, and removing insoluble matters using a filter or the like.

[0041] Next, the ink jet recording apparatus of the present invention will be described.

[0042] The inkjet recording apparatus of the present invention includes an ink storage section and an ink ejection means, and ejects ink stored in the ink storage section by the ink ejection means, and is characterized in that the ink storage section contains the water-based ink for inkjet recording of the present invention.

[0043] The configuration of one example of the inkjet recording device of the present invention is shown in Figure 2. As shown in the figure, this inkjet recording device 1 includes, as main components, four ink cartridges 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.

[0044] The four ink cartridges 2 each contain one of the four water-based inks of yellow, magenta, cyan, and black. For example, the water-based magenta ink is the water-based ink for ink-jet recording of the present invention. In this example, a set of four ink cartridges 2 is shown, but instead of this, an integrated ink cartridge whose interior is partitioned to form a water-based yellow ink storage section, a water-based magenta ink storage section, a water-based cyan ink storage section, and a water-based black ink storage section may be used. As the main body of the ink cartridge, for example, a conventionally known one may be used.

[0045] The inkjet head 3 mounted on the head unit 4 performs recording on a recording medium (e.g., recording paper) P. The carriage 5 is mounted with four ink cartridges 2 and the head unit 4. The drive unit 6 moves the carriage 5 back and forth in a linear direction. As the drive unit 6, for example, a conventionally known one can be used (for example, see JP 2008-246821 A). The platen roller 7 extends in the reciprocating direction of the carriage 5, and is disposed opposite the inkjet head 3.

[0046] The purging device 8 sucks up defective ink containing air bubbles and the like that accumulates inside the inkjet head 3. As the purging device 8, for example, a conventionally known device can be used (for example, see JP-A-2008-246821).

[0047] A wiper member 20 is disposed adjacent to the purging device 8 on the platen roller 7 side of the purging device 8. The wiper member 20 is formed in a spatula shape, and wipes the nozzle formation surface of the inkjet head 3 as the carriage 5 moves. In Fig. 2, a cap 18 covers the multiple nozzles of the inkjet head 3, which are returned to a reset position when recording is completed, in order to prevent the water-based ink from drying.

[0048] In the inkjet recording device 1 of this embodiment, the four ink cartridges 2 are mounted on one carriage 5 together with the head unit 4. However, the present invention is not limited to this. In the inkjet recording device 1, each of the four ink cartridges 2 may be mounted on a carriage separate from the head unit 4. Also, each of the four ink cartridges 2 may not be mounted on the carriage 5, but may be arranged and fixed within the inkjet recording device 1. 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 the water-based ink is supplied from each of the four ink cartridges 2 to the head unit 4. Also, in these embodiments, four bottle-shaped ink bottles may be used instead of the four ink cartridges 2. In this case, it is preferable that the ink bottle is provided with an injection port for injecting ink from the outside into the inside.

[0049] Inkjet recording using this inkjet recording apparatus 1 is carried out, for example, as follows. First, recording paper P is fed from a paper feed cassette (not shown) provided to 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. A predetermined recording is made on the introduced recording paper P using water-based ink ejected from the inkjet head 3. After recording, the recording paper P is discharged from the inkjet recording apparatus 1. In FIG. 2, the paper feed mechanism and paper discharge mechanism for the recording paper P are not shown.

[0050] 2 employs a serial type inkjet head, but the present invention is not limited to this. The inkjet recording device may employ a line type inkjet head.

[0051] Next, the inkjet recording method of the present invention is an inkjet recording method for ejecting an aqueous ink onto a recording medium by an inkjet system, and is characterized in that the aqueous ink for inkjet recording of the present invention is used as the aqueous ink. The recording includes printing, photographic printing, printing, and the like. EXAMPLES

[0052] Next, examples of the present invention will be described together with comparative examples. Note that the present invention is not limited or restricted by the following examples and comparative examples.

[0053] [Preparation of pigment dispersions A to D] Pure water was added to 20% by mass of pigment (solid solution of PR202 and PV19) and 7% by mass of sodium hydroxide neutralized styrene-acrylic acid copolymer (acid value 175 mgKOH / g, molecular weight 10000) to make the total 100% by mass, and the mixture was stirred and mixed to obtain a mixture. This mixture was placed in a wet sand mill filled with 0.3 mm diameter zirconia beads and dispersed for 6 hours. The zirconia beads were then removed using a separator, and the mixture was filtered through a cellulose acetate filter with a pore size of 3.0 μm to obtain pigment dispersion A shown in Tables 1 and 2. The styrene-acrylic acid copolymer is a water-soluble polymer that is generally used as a dispersant for pigments. In addition, pigment dispersions B to D shown in Tables 1 and 2 were obtained in the same manner, except that the pigment type, component ratio, and dispersion treatment time were appropriately changed.

[0054] [Examples 1 to 17 and Comparative Examples 1 to 6] The components in the ink composition (Table 1 or Table 2) except for the pigment dispersion were mixed uniformly to obtain an ink solvent. Next, the ink solvent was added to the pigment dispersion and mixed uniformly. The mixture obtained was then filtered through a cellulose acetate type membrane filter (pore size 3.00 μm) manufactured by Toyo Roshi Kaisha, Ltd. to obtain the water-based inks for inkjet recording of Examples 1 to 17 shown in Table 1 and the water-based inks for inkjet recording of Comparative Examples 1 to 6 shown in Table 2.

[0055] For the water-based inks of Examples 1 to 17 and Comparative Examples 1 to 6, (a) hue angle evaluation, (b) magenta chroma evaluation, and (c) recording density evaluation were carried out by the following methods.

[0056] (a) Hue angle evaluation The water-based inks of the examples and comparative examples were applied in an amount of about 0.90 mg / cm2 per unit area. 2 The test sample was prepared by applying the test solution to a recording medium ("Hammermill Fore Multi-Purpose Paper" manufactured by International Paper Co., Ltd.) so that the test sample satisfies the following criteria: The hue angles at five points in the test sample were measured using a spectrophotometer SpectroEye manufactured by X-Rite Co., Ltd., the average value was calculated, and the test sample was evaluated according to the following criteria:

[0057] Hue angle evaluation criteria A: The hue angle was between -2° and 7°. B: The hue angle was -5° or more and less than -2°, or more than 7° and less than 11°. C: The hue angle was less than -5° or more than 11°.

[0058] (b) Magenta chroma evaluation The chroma (C * ) was measured using the above-mentioned spectrophotometer SpectroEye, the average value was calculated, and the magenta chroma was evaluated according to the following evaluation criteria.

[0059] Magenta chroma rating Evaluation criteria A: Saturation (C * ) was over 70. B: Saturation (C * ) was between 66 and 70. C: Saturation (C * ) was less than 66.

[0060] (c) Recording concentration evaluation The optical density (OD value) at five points in the evaluation sample in the above-mentioned (a) hue angle evaluation was measured using the SpectroEye spectrophotometer (light source: D 50 The recording density was measured under the following conditions (viewing angle: 2°, ANSI-T), the average value was calculated, and the recording density was evaluated according to the following evaluation criteria.

[0061] Recording density evaluation Evaluation criteria AA: The optical density (OD value) was 1.30 or more. A: The optical density (OD value) was 1.20 or more and less than 1.30. B: The optical density (OD value) was 1.12 or more and less than 1.20. C: The optical density (OD value) was less than 1.12.

[0062] The compositions and evaluation results of the water-based inks of Examples 1 to 17 and Comparative Examples 1 to 6 are shown in Tables 1 and 2 below.

[0063] [Table 1]

[0064] [Table 2]

[0065] As shown in Table 1, in Examples 1 to 17, the evaluation results of all of the hue angle, magenta chroma, and recording density were good.

[0066] In Examples 3 to 6 and 8 to 13, in which Q:A=7:3 to 4:6 and Q+A was 5% to 8% by mass, the balance of the hue angle, magenta chroma, and recording density was better than that in Examples 1, 2, 15, and 16, in which Q:A=9:1, 8:2, 3:7, and 2:8, and in Example 14, in which Q+A=9% by mass. Similarly, in Examples 4 to 7 and 17, in which Q:A=7:3 to 5:5 and Q+A was 6% to 9% by mass, the balance of the hue angle, magenta chroma, and recording density was better than that in Examples 1, 2, and 14 to 16.

[0067] In Examples 4 to 6 and 11 to 13, in which Q:A=7:3 to 4:6 and Q+A was 6% to 8% by mass, the hue angle and magenta chroma were superior and the recording density was even superior to Examples 1 to 3, 8 to 10 and 14 to 16, in which Q+A was 5% or 9% by mass. Similarly, in Examples 4 to 7 and 17, in which Q:A=7:3 to 5:5 and Q+A was 6% to 9% by mass, the hue angle and magenta chroma were superior and the recording density was even superior to Examples 1 to 3, 8 to 10 and 14 to 16.

[0068] On the other hand, as shown in Table 2, Comparative Example 1, which did not use an azo pigment, had poor evaluation results for the hue angle. Comparative Example 2, which did not use a quinacridone pigment, had poor evaluation results for the magenta chroma and recording density. Comparative Example 3, which used PR202 instead of a solid solution of PR202 and PV19 as the quinacridone pigment, had poor evaluation results for the magenta chroma, and Comparative Example 4, which used PV19, had poor evaluation results for the hue angle. Comparative Example 5, which used a non-solid solution of PR202 and PV19 instead of a solid solution of PR202 and PV19 as the quinacridone pigment, had poor evaluation results for the magenta chroma and recording density. And Comparative Example 6, in which Q:A=1:9, had poor evaluation results for the magenta chroma. [Industrial Applicability]

[0069] As described above, the water-based ink of the present invention can achieve a wide color reproduction range from magenta to red, and also has good magenta chroma and recording density. The water-based ink of the present invention can be widely applied to various ink-jet recordings, for example, as a water-based magenta ink for ink-jet recording. [Explanation of symbols]

[0070] 1 Inkjet recording device 2 Ink cartridges 3. Ink ejection means (inkjet head) 4 Head Unit 5 Carriage 6 Drive unit 7 Platen roller 8 Purging device

Claims

1. A water-based ink for ink-jet recording, comprising: A quinacridone pigment, an azo pigment, and water, The quinacridone pigment comprises a solid solution comprising C.I. Pigment Red 202 and C.I. Pigment Violet 19; The azo pigment contains C.I. Pigment Red 146, and a pigment dispersion having a pigment solid content of the azo pigment of 10% by mass is contained in the aqueous ink for ink-jet recording in an amount of 18 to 48% by weight, a mass ratio of the total content of the quinacridone pigment (Q) to the total content of the azo pigment (A) is Q:A=7:3 to 4:6; and The total content (Q+A) of the quinacridone pigment (Q) and the azo pigment (A) is 6% by mass to 9% by mass.

1. A water-based ink for ink-jet recording.

2. 2. The water-based ink for ink-jet recording according to claim 1, wherein the total content (Q) of the quinacridone pigment and the content (A) of the azo pigment, (Q+A), is 6% by mass to 8% by mass.

3. 2. The water-based ink for ink-jet recording according to claim 1, wherein a mass ratio of a content (Q) of the quinacridone pigment to a content (A) of the azo pigment in a total amount is Q:A=7:3 to 5:

5.

4. An aqueous ink for inkjet recording described in any of claims 1 to 3, wherein the quinacridone pigment is contained in a pigment dispersion having a pigment solids content of 10 mass % of the quinacridone pigment in an amount of 24 to 63 weight % in the aqueous ink for inkjet recording.

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