Water-based ink for inkjet recording, fixer, inkjet recording method, inkjet recording apparatus, and ink container.

Abstract

To provide a water-based ink for inkjet recording, containing polylactic acid as a fixing agent.SOLUTION: A water-based ink for inkjet recording contains water, a coloring agent, and a fixing agent. The fixing agent contains polylactic acid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous ink for inkjet recording, a fixing agent, an inkjet recording method, an inkjet recording apparatus, and an ink storage container.

Background Art

[0002] As the aqueous ink for inkjet recording, for example, those described in Patent Document 1 are common.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, with the increasing awareness of environmental problems, the reduction of environmental impact has also been demanded for aqueous inks for inkjet recording.

[0005] Therefore, an object of the present invention is to provide an aqueous ink for inkjet recording that can contribute to the reduction of environmental impact.

Means for Solving the Problems

[0006] To achieve the above object, the aqueous ink for inkjet recording of the present invention contains water, a coloring agent, and a fixing agent, and the fixing agent contains polylactic acid.

Effects of the Invention

[0007] Since the fixing agent contained in the aqueous ink for inkjet recording of the present invention contains polylactic acid having biodegradability, it can contribute to the reduction of environmental impact.

Brief Description of the Drawings

[0008] [Figure 1] Figure 1 is a schematic perspective view showing an example configuration of the inkjet recording apparatus of the present invention. [Modes for carrying out the invention]

[0009] In this invention, the term "mass" may be interpreted as "weight" unless otherwise specified. For example, "mass ratio" may be interpreted as "weight ratio" unless otherwise specified, and "mass%" may be interpreted as "weight%" unless otherwise specified.

[0010] The present invention describes the water-based inkjet recording ink (hereinafter sometimes referred to as "water-based ink" or "ink"). The water-based ink of the present invention comprises water, a colorant, and a fixative, the fixative comprising polylactic acid.

[0011] The coloring agent may include, for example, pigments, dyes, etc.

[0012] The aforementioned pigments are not particularly limited and include, for example, carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium dioxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye-type lake pigments and acid dye-type lake pigments; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; and others. In addition, other pigments can be used as long as they are dispersible in the aqueous phase. Specific examples of these pigments include, for example, CI Pigment Black 1, 6 and 7; CI Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 180, 185 and 194; CI Pigment Orange 31 and 43; CI Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123, 1 Examples include 39, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224 and 238; CI Pigment Violet 19 and 196; CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22 and 60; CI Pigment Green 7 and 36; and solid solutions of these pigments.

[0013] The pigment may be dispersed in a solvent by a resin dispersant (also called a resin-dispersed pigment). As the resin dispersant, for example, a general polymer dispersant (also called a pigment dispersion resin or resin dispersant, etc.) may be used, and may be prepared in-house. In addition, in the aqueous ink of the present invention, the pigment may be encapsulated by a polymer. As the resin dispersant, for example, one containing at least one of methacrylic acid and acrylic acid as a monomer can be used, and commercially available products may be used, for example. The resin dispersant may be, for example, a hydrophobic monomer such as styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene derivatives, or aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids, or a block copolymer, graft copolymer, or random copolymer or a salt thereof, consisting of two or more monomers selected from the group consisting of acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, or fumaric acid derivatives. Examples of the aforementioned commercially available products include "Johncryl® 611", "Johncryl® 60", "Johncryl® 586", "Johncryl® 687", "Johncryl® 63", and "Johncryl® HPD296" manufactured by Johnson Polymer Co., Ltd.; "Disperbyk190" and "Disperbyk191" manufactured by Bic Chemie; and "Solspers 20000" and "Solspers 27000" manufactured by Zeneca.

[0014] One method for dispersing the pigment using the aforementioned pigment dispersion resin is to disperse the pigment using a dispersion apparatus. The dispersion apparatus used for dispersing the pigment is not particularly limited as long as it is a general-purpose dispersion machine, but examples include ball mills, roll mills, sand mills (e.g., high-speed type), etc.

[0015] The pigment may be a self-dispersing pigment. The self-dispersing pigment is such that, for example, at least one of a hydrophilic functional group such as a carbonyl group, hydroxyl group, carboxylic acid group, sulfonic acid group, or phosphate group, and salts thereof, is introduced into the pigment particles by chemical bonding, either directly or via other groups, so that it can be dispersed in water without the use of a dispersant. The self-dispersing pigment can be one in which the pigment has been treated by the method described in, for example, Japanese Patent Publication No. 8-3498, Japanese Patent Publication No. 2000-513396, Japanese Patent Publication No. 2008-524400, Japanese Patent Publication No. 2009-515007, Japanese Patent Publication No. 2011-515535, etc. The raw material for the self-dispersing pigment can be either an inorganic pigment or an organic pigment. Examples of pigments suitable for the above treatment include carbon black such as "MA8" and "MA100" manufactured by Mitsubishi Chemical Corporation. The self-dispersing pigment can be a commercially available product, for example. Examples of the aforementioned commercially available products include "CAB-O-JET(registered trademark) 200", "CAB-O-JET(registered trademark) 250C", "CAB-O-JET(registered trademark) 260M", "CAB-O-JET(registered trademark) 270Y", "CAB-O-JET(registered trademark) 300", "CAB-O-JET(registered trademark) 400", "CAB-O-JET(registered trademark) 450C", "CAB-O-JET(registered trademark) 465M", and "CAB-O-JET(registered trademark) 470Y" manufactured by Cabot Corporation; "BONJET(registered trademark) BLACK CW-2" and "BONJET(registered trademark) BLACK CW-3" manufactured by Orient Chemical Industry Co., Ltd.; and "LIOJET(registered trademark) WD BLACK 002C" manufactured by Toyo Ink Manufacturing Co., Ltd.

[0016] As mentioned above, the fixing agent contains polylactic acid. The origin of the raw material for the polylactic acid is not particularly limited, and may include, for example, plant-derived polylactic acid and non-plant-derived (chemically synthesized) polylactic acid. Plant-derived polylactic acid is produced from, for example, starch or sugar. Using plant-derived polylactic acid can also contribute to the reduction of CO2 emissions.

[0017] The fixing agent may contain components other than the polylactic acid. The components other than the polylactic acid are not particularly limited. For example, there is a fixing agent synthesized from raw materials derived from chemical synthesis.

[0018] The fixing agent is for fixing the colorant to the recording medium. The recording medium is not particularly limited. For example, recording paper and the like can be mentioned.

[0019] The water may be ion-exchanged water, pure water, or the like.

[0020] The water may be the main solvent. In the present invention, the "main solvent" refers to the most abundant component among the components constituting the solvent. The blending amount (water ratio) of the water with respect to the total amount of the aqueous ink 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, 50% by mass to 95% by mass, preferably 55% by mass to 90% by mass, more preferably 60% by mass to 80% by mass.

[0021] The addition amount of the polylactic acid with respect to the total amount of the aqueous ink is not particularly limited. For example, it may be 2.5% by mass or more, or 3% by mass or more, and may also be 10% by mass or less, 7% by mass or less, or 5% by mass or less. For example, it is 2.5% by weight to 10% by weight, preferably 3% by weight to 10% by weight, more preferably 3% by weight to 7% by weight.

[0022] The mass ratio (A / B) of the content (A) of the pigment to the content (B) of the polylactic acid with respect to the total amount of the aqueous ink is not particularly limited. For example, it is 0.25 to 1.0, preferably 0.5 to 0.85, more preferably 0.5 to 0.83.

[0023] The viscosity of the aqueous ink may be, for example, 20 mPa·s or less, 10 mPa·s or less, 7 mPa·s or less, or 5 mPa·s or less, and may also be 1 mPa·s or more, or 2 mPa·s or more. For example, it is 1 to 20 mPa·s, preferably 2 to 10 mPa·s.

[0024] The aqueous ink may further contain, for example, a wetting agent.

[0025] 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, 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; alkylene glycol; polyhydric alcohols such as glycerin, trimethylolpropane, and trimethylolethane; 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. Among these, polyhydric alcohols such as alkylene glycol and glycerin are preferred.

[0026] The aqueous ink may further contain, for example, a surfactant.

[0027] The surfactant is not particularly limited and can be appropriately selected according to the purpose. For example, commercially available products may be used. Specifically, examples of the surfactant include silicone-based surfactants and acetylene-based surfactants.

[0028] Examples of commercially available silicone-based surfactants include "Sylface® SAG002", "Sylface® SAG005", and "Sylface® SAG503A" manufactured by Nisshin Chemical Industry Co., Ltd.

[0029] 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.

[0030] The aqueous ink may contain other surfactants in addition to / instead of the silicone-based surfactant and the acetylene-based surfactant. Other surfactants include, for example, 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.; the nonionic surfactants "DOBANOX®" series, "LEOCOL®" series, "LEOX®" series, "LAOL,LEOCOL®" series, "LIONOL®" series, "CADENAX®" series, "LIONON®" series and "LEOFAT®" series manufactured by Lion Corporation; and the anionic surfactants "EMAL®" series, "LATEMUL®" series, "VENOL®" series, "NEOPELEX®" series, NS SOAP, KS SOAP, OS Examples include 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".

[0031] The aforementioned surfactant may be used individually or in combination of two or more types.

[0032] The aqueous ink may further contain, for example, an organic solvent as a solvent other than water. However, from the viewpoint of reducing volatile organic compounds (VOCs), the content of the organic solvent in the aqueous ink can be set low, or it can be set to contain no organic solvent at all.

[0033] The aqueous ink may further contain conventionally known additives as needed. Examples of such 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] Next, the fixer of the present invention is a fixer for an aqueous inkjet recording ink, and is characterized by containing polylactic acid. If the fixer of the present invention contains a fixer component other than polylactic acid, for example, a component of the aqueous ink other than polylactic acid can be used.

[0035] Next, the ink storage container of the present invention is an ink storage container containing an aqueous ink for inkjet recording, characterized in that the aqueous ink is the aqueous ink for inkjet recording of the present invention. For example, conventionally known ink storage containers can be used. Examples of such ink storage containers include ink cartridges, tanks, pouches, and the like.

[0036] Next, the inkjet recording apparatus and inkjet recording method of the present invention will be described.

[0037] The present invention relates to an inkjet recording apparatus that includes an ink storage section and an ink ejection section, wherein the ink stored in the ink storage section is ejected by the ink ejection section, and the ink storage section is characterized in that the aqueous inkjet recording ink of the present invention is stored in the ink storage section.

[0038] Figure 1 shows the configuration of an example of the inkjet recording apparatus of the present invention. As shown in the figure, this inkjet recording apparatus 1 mainly includes four ink storage units (ink cartridges 2), an ink ejection unit (inkjet head) 3, a head unit 4, a carriage 5, a drive unit 6, a platen roller 7, and a purge device 8.

[0039] The four ink cartridges 2 each contain one of four water-based inks: yellow, magenta, cyan, and black. For example, at least one of the four water-based inks is the water-based ink of the present invention. In this example, a set of four ink cartridges 2 is shown, but instead, an integrated ink cartridge may be used, 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. For the body of the ink cartridge, for example, a conventionally known one can be used.

[0040] The inkjet head 3, installed in the head unit 4, records on the recording medium (e.g., recording paper) P. The carriage 5 is equipped 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. For example, a conventionally known drive unit 6 can be used (see, for example, Japanese Patent Application Publication No. 2008-246821). The platen roller 7 extends in the reciprocating direction of the carriage 5 and is positioned opposite the inkjet head 3.

[0041] The inkjet head 3 is constructed, for example, by stacking multiple layers of thin metal plates. Each plate has a through-hole formed in it. Multiple layers of plates with through-holes are stacked to form a channel for the water-based ink to pass through. The plates are bonded together, for example, with an adhesive.

[0042] The purging device 8 sucks up defective ink containing air bubbles and other debris that accumulates inside the inkjet head 3. For example, a conventionally known device can be used as the purging device 8 (see, for example, Japanese Patent Application Publication No. 2008-246821).

[0043] A wiper member 20 is positioned adjacent to the purge device 8 on the platen roller 7 side. The wiper member 20 is shaped like a spatula and wipes the nozzle forming surface of the inkjet head 3 as the carriage 5 moves. In Figure 1, the cap 18 covers the multiple nozzles of the inkjet head 3, which are returned to the reset position when recording is finished, in order to prevent the water-based ink from drying out.

[0044] In the inkjet recording device 1 of this example, the four ink cartridges 2 are mounted on a single 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. Alternatively, each of the four ink cartridges 2 may not be mounted on the carriage 5, but rather 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 aqueous 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, it is preferable that the ink bottles are provided with an inlet for injecting ink from the outside into the inside.

[0045] Inkjet recording using this inkjet recording device 1 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 inkjet recording device 1. The recording paper P is introduced between the inkjet head 3 and the platen roller 7. A predetermined record is made on the introduced recording paper P by aqueous ink ejected from the inkjet head 3. This ejection may be performed, for example, with a first ejection amount as described above, or with a second ejection amount when certain conditions are met. After recording, the recording paper P is ejected from the inkjet recording device 1. In Figure 1, the paper feeding mechanism and paper ejection mechanism for the recording paper P are not shown.

[0046] The apparatus shown in Figure 1 employs a serial inkjet head, but the present invention is not limited thereto. The inkjet recording apparatus may also employ a line inkjet head or a roll-to-roll system.

[0047] Next, the inkjet recording method of the present invention is an inkjet recording method that includes a recording step of ejecting aqueous ink onto a recording medium by an inkjet method, characterized in that, in the recording step, the aqueous inkjet recording aqueous ink of the present invention is used as the aqueous ink. The inkjet recording method of the present invention can be carried out, for example, using the inkjet recording apparatus of the present invention. The recording includes printing, image printing, and the like. [Examples]

[0048] Next, embodiments of the present invention will be described together with comparative examples. However, the present invention is not limited to or restricted by the following embodiments and comparative examples.

[0049] (Fixing resin A) Fixing resin A was synthesized by reacting glycols with polyisocyanate. The acid value was controlled by adjusting the mixing ratio and functional groups such as carboxyl groups and amino groups. The acid value of fixing resin A was 48. The acid value was measured according to JIS K2501.

[0050] (Preparation of Pigment Dispersion A) A mixture was prepared by adding pure water to 20% by mass of pigment (CI pigment blue 15:3) and 7% by mass of sodium hydroxide neutralized styrene-acrylic acid copolymer (acid value 50 mg KOH / g, molecular weight 10000) to make a total of 100% by mass, and stirring to obtain a mixture. This mixture was placed in a wet sand mill packed with 0.3 mm diameter zirconia beads and dispersed for 6 hours. After that, the zirconia beads were removed with a separator, and the mixture was filtered through a 3.0 μm pore size cellulose acetate filter to obtain pigment dispersion A. Styrene-acrylic acid copolymer is a water-soluble polymer commonly used as a dispersant for pigments.

[0051] (Examples 1-7, Comparative Examples 1-3) The components of the aqueous ink composition (Table 1), excluding the colorant, were uniformly mixed to obtain an ink solvent. Next, the colorant was added to the ink solvent and uniformly mixed. Subsequently, the resulting mixture was filtered through a cellulose acetate type membrane filter (pore size 3.00 μm) manufactured by Toyo Roshi Co., Ltd. to obtain the aqueous inkjet recording inks of Examples 1-7 and Comparative Examples 1-3 shown in Table 1.

[0052] For the aqueous inks of Examples 1-7 and Comparative Examples 1-3, (a) viscosity (IJ ejection properties), (b) fixation properties, and (c) storage stability were evaluated by the following methods.

[0053] (a) Viscosity (IJ discharge properties) Viscosity was measured at 25°C using a viscometer (TVE-25 model, manufactured by Toki Sangyo Co., Ltd.) and evaluated according to the following evaluation criteria.

[0054] Viscosity (IJ discharge performance) evaluation criteria A: Viscosity 10.0mPa·s or less B: Viscosity exceeding 10.0 mPa·s

[0055] (b) Fixation Drawdown was performed on glossy photographic paper (BP71G, manufactured by Brother Industries, Ltd.) to obtain evaluation samples. After drying at room temperature for one day, cellophane tape (registered trademark) manufactured by Nichiban Co., Ltd. was attached to the evaluation samples and left at room temperature for 10 minutes, after which it was peeled off at a constant speed. Subsequently, the optical density (OD value) of three locations on the peeled area of ​​the evaluation sample was measured using a SpectroEye spectrophotometer manufactured by X-Rite (light source: D50, field of view: 2°, ANSI-T), the average value was calculated, and the samples were evaluated according to the evaluation criteria below.

[0056] Criteria for evaluating retention A: Decrease in optical density (OD value) from before peeling is 5% or less. B: The decrease in optical density (OD value) from before peeling is greater than 5% but less than or equal to 10%. C: Decrease in optical density (OD value) from before peeling exceeds 10%.

[0057] (c) Storage stability The aqueous ink, prepared immediately after its viscosity was measured, was placed in a sealed container and stored for one week at a temperature of 60°C and a relative humidity of 40%. The viscosity of the evaluation samples prepared in this manner was measured, and their storage stability was evaluated according to the evaluation criteria below. The viscosity was measured at 25°C using a viscometer (TVE-25 model, manufactured by Toki Sangyo Co., Ltd.).

[0058] Storage stability evaluation criteria A: Viscosity change rate after 1 week at 60°C is 5% or less. B: Viscosity change rate exceeds 5% after 1 week at 60°C

[0059] The environmental performance shown in Table 1 was evaluated according to the following evaluation criteria. The environmental performance evaluation tests were conducted in accordance with ASTM D5338 (ISO 14855). A: Contains at least 60% of biodegradable raw materials among the non-volatile components in the composition. C: Of the non-volatile components in the composition, less than 60% are biodegradable raw materials.

[0060] The volatile organic compounds (VOCs) in Table 1 were evaluated according to the following evaluation criteria. A: Does not contain organic solvents with a boiling point below 250°C. C: Contains organic solvents with a boiling point of 250°C or less.

[0061] Table 1 shows the aqueous ink compositions and evaluation results of the aqueous inks used in Examples 1-7 and Comparative Examples 1-3.

[0062] [Table 1]

[0063] As shown in Table 1, Examples 1 to 7 had an environmental compatibility and VOC evaluation of "A" or higher, and a fixation rate of "B" or higher.

[0064] Examples 1 and 3-7, in which the amount of polylactic acid added to the total amount of the aqueous ink was 3% by mass or more and 10% by mass or less, showed better fixation than the other examples.

[0065] Examples 4 to 6, in which the mass ratio (A / B) of the pigment content (A) to the polylactic acid content (B) in the total amount of the aqueous ink was 0.5 or more and 0.85 or less, showed better fixation and storage stability than the other examples.

[0066] Examples 4 and 5, in which the viscosity of the aqueous ink was 10 mPa·s or less, showed superior fixation, storage stability, and inkjet ejection compared to the other examples.

[0067] On the other hand, Comparative Example 1, which used a chemically synthesized fixing agent component, was less environmentally friendly than Example 1. Furthermore, since there was no difference in evaluation results between Comparative Example 2, which used the VOC methyl ethyl ketone, and Example 1, Example 1, which used only water as a solvent, is superior from the standpoint of protecting the global environment. Comparative Example 3, which did not contain a fixing agent, had poor fixing performance.

[0068] The above embodiments and some or all of the examples may also be described as follows, but are not limited to these. (Note 1) Contains water, colorants, and fixatives. The aforementioned fixing agent is characterized by containing polylactic acid, and is an aqueous ink for inkjet recording. (Note 2) The aqueous inkjet recording ink according to Appendix 1, characterized in that the aforementioned water is the main solvent. (Note 3) The aforementioned coloring agent is characterized by containing a pigment, as described in Appendix 1 or 2, for an aqueous inkjet recording ink. (Note 4) The aqueous inkjet recording ink described in Appendix 3, wherein the fixing agent is for fixing the pigment to a recording medium. (Note 5) The water-based inkjet recording ink according to any one of the appendices 1 to 4, characterized in that the amount of polylactic acid added to the total amount of the water-based inkjet recording ink is 3% by mass or more and 10% by mass or less. (Note 6) The water-based inkjet recording ink according to Appendix 3 or 4, characterized in that the mass ratio (A / B) of the pigment content (A) to the polylactic acid content (B) in the total amount of the water-based inkjet recording ink is 0.5 or more and 0.85 or less. (Note 7) The water-based inkjet recording ink according to any one of the appendices 1 to 6, characterized in that the viscosity of the water-based inkjet recording ink is 10 mPa·s or less. (Note 8) A fixative for water-based inkjet recording, characterized by containing polylactic acid. (Note 9) The recording process includes ejecting water-based inkjet recording ink onto a recording medium using an inkjet method. An inkjet recording method characterized in that, in the recording step, the water-based inkjet recording ink described in any one of the appendices 1 to 7 is used as the water-based inkjet recording ink. (Note 10) Including an ink storage section and an ink ejection means, An inkjet recording apparatus that ejects ink contained in the ink storage section by the ink ejection means, An inkjet recording apparatus characterized in that the ink storage section contains an aqueous inkjet recording ink described in any one of the appendices 1 to 7. (Note 11) An ink container containing an inkjet water-based ink, characterized in that the inkjet water-based ink is an inkjet water-based ink described in any one of the appendices 1 to 7. [Industrial applicability]

[0069] As described above, the aqueous ink of the present invention has good environmental friendliness due to the inclusion of polylactic acid as a fixative. The aqueous ink of the present invention can be widely applied to inkjet recording on various recording media. [Explanation of Symbols]

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

Claims

1. Contains water, colorants, and fixatives. The aforementioned coloring agent contains a pigment, The fixing agent contains polylactic acid, An inkjet water-based inkjet recording ink characterized in that the mass ratio (A / B) of the pigment content (A) to the polylactic acid content (B) in the total amount of the water-based inkjet recording ink is 0.25 or more and 1.0 or less.

2. The aqueous inkjet recording ink according to claim 1, characterized in that the water is the main solvent.

3. The aqueous inkjet recording ink according to claim 1 or 2, wherein the fixing agent is for fixing the pigment to a recording medium.

4. The water-based inkjet recording ink according to claim 1 or 2, characterized in that the amount of polylactic acid added to the total amount of the water-based inkjet recording ink is 3% by mass or more and 10% by mass or less.

5. The water-based inkjet recording ink according to claim 1 or 2, characterized in that the mass ratio (A / B) of the pigment content (A) to the polylactic acid content (B) in the total amount of the water-based inkjet recording ink is 0.5 or more and 0.85 or less.

6. The water-based inkjet recording ink according to claim 1 or 2, characterized in that the viscosity of the water-based inkjet recording ink is 10 mPa·s or less.

7. The recording process includes ejecting water-based inkjet recording ink onto a recording medium using an inkjet method. An inkjet recording method characterized in that, in the recording step, the water-based inkjet recording ink described in claim 1 or 2 is used as the water-based inkjet recording ink.

8. Including an ink storage section and an ink ejection means, An inkjet recording apparatus that ejects ink contained in the ink storage section by the ink ejection means, An inkjet recording apparatus characterized in that the ink storage section contains the aqueous ink for inkjet recording described in claim 1 or 2.

9. An ink container containing an aqueous ink for inkjet recording, characterized in that the aqueous ink for inkjet recording is the aqueous inkjet recording ink described in claim 1 or 2.

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