Ink set and recording method

Abstract

To provide an ink set which is excellent in wet spread properties of a black ink composition, and can excellently reduce color mixture between the black ink composition and a chromatic ink composition.SOLUTION: An ink set has a black ink composition containing a black colorant and a chromatic ink composition containing a colorant, and is used in recording in a low absorptive recording medium or a non-absorptive recording medium, wherein the black ink composition and the chromatic ink composition are aqueous inkjet ink, the chromatic ink composition contains a silicone-based surfactant 1 having a maximum peak having a molecular weight of 300 or more of 3,000-20,000, in molecular weight distribution in gel permeation chromatography, and the black ink composition contains a glycol monoether solvent, or contains a silicone-based surfactant 2 having a maximum peak having a molecular weight of 300 or more of 300-1,500, in molecular weight distribution in gel permeation chromatography.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an ink set and a recording method. [Background technology]

[0002] The inkjet recording method is capable of recording high-resolution images using a relatively simple device, and has been rapidly developing in various fields. Among these, various studies have been conducted on recording on recording media with low liquid absorbency using ink sets containing multiple types of inks that use water as the main solvent.

[0003] For example, Patent Document 1 discloses an ink set that includes a black ink (black ink composition) and a color ink (chromatic color ink composition), which uses water as the main solvent and contains a silicone surfactant, and is used for recording on a recording medium with low liquid absorbency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-167451 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with conventional ink sets, the black ink has poor wettability and spreadability on the recording medium, resulting in poor image quality for black images, and color mixing between the black ink and color inks leads to deterioration in image quality (border bleeding), making it difficult to achieve both. [Means for solving the problem]

[0006] One aspect of the ink set according to the present invention is An ink set comprising a black ink composition containing a black coloring material and a chromatic color ink composition containing a coloring material, It is used for recording on low-absorbency recording media or non-absorbency recording media, the black ink composition and the chromatic color ink composition are water-based inkjet inks, the chromatic color ink composition contains a silicone surfactant 1 that, in a molecular weight distribution measured by gel permeation chromatography, has a maximum peak in the range of 3,000 to 20,000 in a molecular weight range of 300 or more; The black ink composition contains at least one of a glycol monoether solvent and a silicone surfactant 2 having a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography.

[0007] One aspect of the recording method according to the present invention is to A recording method for recording on a low-absorbency recording medium or a non-absorbency recording medium using the ink set of the above aspect, comprising: a black ink applying step of applying the black ink composition to the recording medium by an inkjet method; and a chromatic ink applying step of applying the chromatic ink composition to the recording medium by an ink jet method. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an example of an inkjet recording apparatus. [Figure 2] FIG. 1 is a schematic diagram of the periphery of a carriage in an example of an inkjet recording apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described. The embodiments described below are examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified forms that are implemented within the scope of the present invention. Note that not all of the configurations described below are necessarily essential configurations of the present invention.

[0010] 1. Ink set An ink set according to one embodiment of the present invention comprises: An ink set comprising a black ink composition containing a black coloring material and a chromatic color ink composition containing a coloring material, It is used for recording on low-absorbency recording media or non-absorbency recording media, the black ink composition and the chromatic color ink composition are water-based inkjet inks, the chromatic color ink composition contains a silicone surfactant 1 that, in a molecular weight distribution measured by gel permeation chromatography, has a maximum peak in the range of 3,000 to 20,000 in a molecular weight range of 300 or more; The black ink composition contains at least one of a glycol monoether solvent and a silicone surfactant 2 having a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography.

[0011] Hereinafter, "silicone surfactant 1, which in the molecular weight distribution measured by gel permeation chromatography has a maximum peak in the range of 3,000 to 20,000 within the range of molecular weights of 300 or more" will be referred to as "specific silicone surfactant 1" or simply as "silicone surfactant 1." Furthermore, "silicone surfactant 2, which in the molecular weight distribution measured by gel permeation chromatography has a maximum peak in the range of 300 to 1,500 within the range of molecular weights of 300 or more" will be referred to as "specific silicone surfactant 2" or simply as "silicone surfactant 2." Furthermore, when no particular distinction is made between a black ink composition (black ink) and a chromatic ink composition (color ink), they will be simply referred to as "ink composition" or "ink."

[0012] When recording on a non-absorbent recording medium or a low-absorbent recording medium, which is a recording medium that does not absorb or barely absorbs a liquid such as ink, it is necessary for the ink to wet and spread on the recording medium in order to obtain excellent image quality. In particular, black ink is often used to record images that include thin lines such as letters. Therefore, if the black ink has poor wet and spread properties, it becomes difficult to depict high-quality thin lines, and the lines become thin or broken, making the letters difficult to read. Therefore, wet and spread properties are particularly important for black ink, and black inks with excellent wet and spread properties are desired.

[0013] However, when recording on a non-absorbent or low-absorbent recording medium, ink tends to remain on the recording medium without being absorbed. As a result, ink droplets come into contact with ink droplets of a different color on the recording medium, easily causing inter-color mixing between the inks. In particular, when black ink droplets penetrate into color ink droplets, the colored portions of the image contaminated by black become conspicuous, which can easily degrade image quality. Conversely, even if color ink droplets penetrate into black ink droplets, the color ink is less visible in the black portions of the image, so image quality is less likely to deteriorate. Therefore, it is a priority to develop an ink composition that makes it difficult for black ink droplets to penetrate into color ink droplets.

[0014] For example, by reducing the content of components such as silicone surfactants that lower the surface tension of the ink and increase its permeability in the black ink compared to the color inks, it becomes possible to make it difficult for black ink droplets to penetrate into color ink droplets. However, with such an ink composition, the black ink does not have sufficient wettability and spreadability on the recording medium, resulting in the above-mentioned problems and poor color development (OD value) of the black image. Furthermore, if the wettability is insufficient, the ink does not spread evenly across the solid pattern of the image, resulting in uneven image quality.

[0015] It has now been discovered that adding glycol monoether solvent or specific low-molecular-weight silicone surfactant 2 to black ink can improve the wetting and color development of the black ink. However, at the point where the black ink droplets come into contact with the color ink droplets on the recording medium, color mixing occurs, resulting in a deterioration in image quality. This is believed to be because the inclusion of glycol monoether solvent or specific silicone surfactant 2 increases the permeability of the black ink, making it easier for it to penetrate into the color ink. As a result of further intensive research, the inventors of the present invention were able to prevent the above-mentioned color mixing by incorporating a specific high-molecular-weight silicone surfactant 1 into the color ink. It is believed that this is because the specific silicone surfactant 1 has a relatively high molecular weight, and acts to block other ink droplets from penetrating into ink droplets containing this component. In particular, when the solvent component of the ink evaporates on the recording medium and the solid component becomes highly concentrated, it becomes difficult for black ink droplets to penetrate into color ink droplets.

[0016] As described above, with the ink set according to the present embodiment, the black ink has excellent wetting and spreading properties on the recording medium, resulting in excellent color development (OD value) of the black image, and also excellent reduction in color mixing between the black ink and color inks, resulting in excellent image quality (border bleeding).

[0017] In the present invention, the term "ink set" refers to a black ink composition and a chromatic color ink composition used as a set for recording. The black ink composition and the chromatic color ink compositions included in the ink set may be contained in separate ink containers, or may be contained in separate chambers of an integrated ink container.

[0018] The ink set includes at least one black ink composition (one type) and at least one chromatic color ink composition (one type). One or both of the black ink composition and the chromatic color ink composition may be provided in two or more.

[0019] Below, the components contained in the black ink composition and the chromatic color ink compositions included in the ink set according to this embodiment will be described.

[0020] 1.1 Black ink composition The black ink composition included in the ink set according to this embodiment is a water-based inkjet ink, and contains at least a black colorant, a glycol monoether solvent and / or a specific silicone surfactant 2.

[0021] In the present invention, "water-based" means that at least water is used as a main solvent. Furthermore, "inkjet ink" means ink used for recording by ejecting the ink from an inkjet head using an inkjet method.

[0022] 1.1.1 Black colorant The black ink composition included in the ink set according to this embodiment contains a black colorant. is.

[0023] 1.1.1.1 Black colorant The black coloring material may be either a black pigment or a black dye. The black ink composition preferably contains a black pigment, and the pigment may be dispersed in a dispersing resin.

[0024] Examples of black pigments include carbon black such as furnace black, lamp black, acetylene black, and channel black, and examples thereof include CI (Colour Index Generic Name) Pigment Black 1, 7, and 11. Of these, it is preferable to use carbon black that is CI Pigment Black 7.

[0025] Specific examples of carbon black include Mitsubishi Chemical's No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, and No. 2200B; Columbia Carbon's Raven (registered trademark) 5750, 5250, 5000, 3500, 1255, and 700; CABOT's Rega1 (registered trademark) 400R, 330R, and 660R, Mogul (registered trademark) L, and Monarch (registered trademark) 700, 800, 880, 900, 1000, 1100, 1300, and 1400; and Degussa's Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, and S170, Printex (registered trademark) 35, U, V, and 140U, and Special Black. Examples include 6, 5, 4A, and 4.

[0026] In order to improve the dispersibility of pigments, including black pigments, in ink, it is preferable to subject the pigment to surface treatment or to incorporate a dispersant or the like. Pigment surface treatment is a method of introducing functional groups that have affinity with the ink medium onto the pigment particle surface by physical or chemical treatment. When used in a water-based ink, as in this embodiment, it is preferable to introduce hydrophilic groups such as carboxy groups or sulfo groups.

[0027] When a dispersant is incorporated into the ink composition, it is preferable to use a dispersant that has a hydrophobic portion (hydrophobic group) and a hydrophilic portion (hydrophilic group) in its molecular structure. Such dispersants have the effect that the hydrophobic portion adsorbs to the surface of the pigment particles and the hydrophilic portion orients toward the aqueous medium side of the ink. This effect allows the pigment to be more stably contained in the ink as a dispersion. Such dispersants are not particularly limited, but examples thereof include acrylic resins, styrene-acrylic resins such as styrene-(meth)acrylic acid copolymers and styrene-(meth)acrylic acid-(meth)acrylate copolymers, styrene-maleic acid resins, and salts thereof, formalin condensates of aromatic sulfonates, etc., and one or more selected from these groups can be used. Note that commercially available dispersants may also be used.

[0028] Alternatively, a method of imparting dispersibility by coating pigment particles with a resin or the like may be used. Examples of methods that can be used to coat pigment particles include acid precipitation, phase inversion emulsification, and mini-emulsion polymerization.

[0029] Examples of black dyes include CI Acid Black 1, 2, 24, and 94, CI Food Black 1 and 2, CI Direct Black 19, 38, 51, 71, 154, 168, 171, and 195, and CI Reactive Black 3, 4, and 35.

[0030] The black coloring material may be used alone or in combination of two or more.

[0031] The content of the black colorant can be adjusted appropriately depending on the application, but is preferably from 0.1 to 17.0% by mass, more preferably from 0.2 to 15.0% by mass, even more preferably from 1.0 to 10.0% by mass, and particularly preferably from 2.0 to 5.0% by mass, relative to the total mass of the black ink composition. Note that the above content ranges may also be used when colorants other than the black colorant are contained.

[0032] 1.1.1.2 Colorants other than black colorants The black ink composition may contain coloring materials other than the above black coloring materials, which will be described later.

[0033] 1.1.2 Water The black ink composition included in the ink set according to this embodiment is a water-based inkjet ink, and contains water. A water-based ink is an ink composition that contains at least water as a main solvent component. An inkjet ink is an ink that is applied to a recording medium by an inkjet method and used for recording.

[0034] The water is not particularly limited, but examples thereof include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water from which ionic impurities have been removed as much as possible. Furthermore, using water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide can prevent the growth of mold and bacteria when the ink composition is stored for a long period of time. This tends to further improve storage stability.

[0035] The water content of the black ink composition is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, particularly preferably 55% by mass or more, more particularly preferably 60% by mass or more, and especially preferably 65% ​​by mass or more, relative to the total mass of the black ink composition. There is no particular upper limit for the water content, but it is preferably 90% by mass or less, more preferably 80% by mass or less, relative to the total mass of the black ink composition.

[0036] 1.1.3 Surfactants The black ink composition provided in the ink set according to this embodiment at least contains a glycol monoether solvent, which will be described later, or a silicone surfactant 2 (specific silicone surfactant 2) that has a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography. Such a specific silicone surfactant 2 is less likely to evaporate on the recording medium than glycol monoether solvents, and therefore maintains high permeability and exhibits particularly excellent wetting and spreading properties.

[0037] The black ink composition included in the ink set according to this embodiment may contain a glycol monoether solvent, which will be described later, and a specific silicone surfactant 2. In such a case, it is preferable because it tends to be possible to achieve a good balance between wetting and spreading properties, abrasion resistance, and prevention of inter-color mixing.

[0038] 1.1.3.1 Certain silicone surfactants2 The specific silicone surfactant 2 has a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography (GPC). By including such a silicone surfactant 2, the wettability and spreadability can be further improved.

[0039] The maximum peak in the range of molecular weight of specific silicone surfactant 2 above 300 is 3 It is in the range of 00 to 1,500, preferably in the range of 500 to 1,500, more preferably in the range of 700 to 1,500, even more preferably in the range of 700 to 1,300, particularly preferably in the range of 800 to 1,100, and even more particularly preferably in the range of 900 to 1,000. When the maximum peak in the molecular weight range of 300 or more is in the range of 300 to 1,500, preferably in the above range, the wet spreadability is further improved, and the image quality (OD value), image quality (unevenness), abrasion resistance, etc. tend to be more excellent.

[0040] The maximum peak in the molecular weight range of 300 or more for specific silicone surfactant 2 can be identified from a GPC molecular weight distribution chart obtained by plotting the logarithm of molecular weight M (LogM) on the horizontal axis and the differential value of concentration fraction (dw / d(LogM)) on the vertical axis. Here, "maximum peak" refers to the largest peak (mountain) in the molecular weight range of 300 or more. Furthermore, "maximum peak in the molecular weight range of 300 or more" means that peaks below 300 are ignored. In other words, although there may be a maximum peak below 300, this refers to the maximum peak when limited to the molecular weight range of 300 or more.

[0041] Although not particularly limited, for example, the measurement conditions for GPC measurement in this embodiment can be the conditions described in the Examples, and the molecular weight can be determined using standard polystyrene.

[0042] Examples of specific silicone surfactant 2 include those represented by general formula (1) described below, in which a is smaller than that of specific silicone surfactant 1 contained in the chromatic color ink composition. Alternatively, examples include those represented by general formula (3) described below, in which d+e is smaller than that of specific silicone surfactant 1. Specific silicone surfactant 2 has a molecular weight that is relatively smaller than that of specific silicone surfactant 1.

[0043] In addition, the specific silicone surfactant 2 may be a commercially available product, such as BYK-349 (a product name manufactured by BYK Japan, with a maximum peak of 1,470 in the molecular weight range of 300 or more in the molecular weight distribution measured by GPC).

[0044] When specific silicone surfactant 2 is contained, the content thereof is preferably 0.05% by mass or more, as a lower limit, relative to the total mass of the black ink composition. It is further preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and particularly preferably 0.4% by mass or more. On the other hand, it is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less, even particularly preferably 0.7% by mass or less, and even more preferably 0.6% by mass or less, relative to the total mass of the black ink composition. It is further preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. When the content of the specific silicone surfactant 2 is within the above range, the ink tends to have excellent wetting and spreading properties, and also tends to have better resistance to inter-ink color mixing and abrasion resistance.

[0045] 1.1.3.2 Other surfactants The black ink composition included in the ink set according to this embodiment may contain a surfactant other than the above-mentioned specific silicone surfactant 2. Examples of surfactants other than the above-mentioned specific silicone surfactant 2 include the specific silicone surfactant 1 contained in the chromatic color ink compositions described below, acetylene glycol surfactants, silicone surfactants (excluding the specific silicone surfactants 1 and 2), and fluorine-based surfactants.

[0046] When the black ink composition further contains a specific silicone surfactant 1, This tends to reduce the fluidity of the black ink composition after it has wetted and spread, thereby better preventing inter-color mixing of the inks. Note that the specific silicone-based surfactant 1 may be the same as or different from the specific silicone-based surfactant 1 contained in the chromatic color ink composition described below.

[0047] The content of specific silicone surfactant 1 is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.5% by mass or less, relative to the total mass of the black ink composition. It is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.2% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less. The lower limit is 0% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more. When the content of the specific silicone surfactant 1 is within the above range, it tends to be possible to achieve both excellent wetting and spreading properties of the black ink composition and excellent prevention of inter-color mixing of the inks.

[0048] The acetylene glycol surfactant is not particularly limited, but examples thereof include alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol and 2,4-dimethyl-5-decyne-4-ol. Commercially available acetylene glycol surfactants include, for example, Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, and DF110D (all trade names, manufactured by Air Products & Chemicals Co.), Ol Examples of such surfactants include Fin B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP.4001, EXP.4036, EXP.4051, AF-103, AF-104, AK-02, SK-14, and AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), and Acetylenol E00, E00P, E40, and E100 (all trade names, manufactured by Kawaken Fine Chemicals Co., Ltd.).

[0049] Silicone surfactants other than the specific silicone surfactants 1 and 2 are not particularly limited, but preferred examples include polysiloxane compounds. Examples of such polysiloxane compounds are not particularly limited, but examples include polyether-modified organosiloxanes. Commercially available examples of such polyether-modified organosiloxanes include SAG503A (trade name, manufactured by Nissin Chemical Industry Co., Ltd., with a maximum peak of 1,820 in the molecular weight range of 300 or more in the molecular weight distribution measured by GPC). Another example is BYK-348.

[0050] The fluorine-based surfactant is not particularly limited, but examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkyl amine oxide compounds. Commercially available fluorine-based surfactants include, for example, BYK-3440 (manufactured by BYK Japan), Surflon S-241, S-242, and S-243 (all trade names, manufactured by AGC Seimi Chemical Co., Ltd.), and Futergent 215M (manufactured by Neos Corporation).

[0051] The black ink composition included in the ink set according to this embodiment preferably has a total content of silicone surfactants, including specific silicone surfactants 1 and 2, of 0% by mass or more, and more preferably 0.1% by mass or more, relative to the total mass of the black ink composition, as the lower limit. It is more preferably 0.2% by mass or more, particularly preferably 0.3% by mass or more, and even more particularly preferably 0.4% by mass or more. The lower limit may be 0% by mass. The upper limit is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less, even more particularly preferably 0.7% by mass or less, and especially preferably 0.6% by mass or less, relative to the total mass of the black ink composition.

[0052] Furthermore, the total content of silicone surfactants in the chromatic color ink compositions described below is preferably equal to or greater than the total content of silicone surfactants in the black ink composition, and is preferably greater than the total content of silicone surfactants in the black ink composition. When this relationship is met, color mixing between ink colors tends to be more effectively prevented. Furthermore, the total content of silicone surfactants in the chromatic ink composition is preferably at least 0.1% by mass higher, more preferably 0.2 to 4% by mass higher, and even more preferably 0.3 to 1% by mass higher, than the total content of silicone surfactants in the black ink composition.

[0053] 1.1.4 Organic solvents The black ink composition included in the ink set according to this embodiment may contain an organic solvent. Examples of the organic solvent include glycol monoether solvents and solvents other than glycol monoether solvents.

[0054] 1.1.4.1 Glycol monoether solvents The black ink composition included in the ink set according to this embodiment contains at least one of a glycol monoether solvent and the specific silicone surfactant 2 described above. Glycol monoether solvents can improve the wetting and spreading properties of ink while reducing inter-color mixing of ink. This is presumably because, immediately after ink impact, the glycol monoether solvent's excellent permeability allows the ink to spread, but because the glycol monoether solvent is prone to evaporate on the recording medium, its permeability decreases after evaporation, making color mixing less likely. Furthermore, when a glycol monoether solvent is included, in addition to excellent wetting and spreading properties and color mixing prevention properties, it also tends to have better abrasion resistance because it is prone to evaporate in the post-drying process, which is the process that completes the drying of the printed matter.

[0055] As mentioned above, the black ink composition included in the ink set according to this embodiment may contain a glycol monoether solvent and the above-mentioned specific silicone surfactant 2. In such a case, it is preferable because it tends to be possible to achieve a good balance between wetting and spreading properties, abrasion resistance, and prevention of inter-color mixing.

[0056] Examples of glycol monoether solvents include glycol monoethers in which one of the hydroxyl groups of the alkane polyols described below is etherified. The etherified glycol monoethers include alkyl ethers and aryl ethers, with alkyl ethers being preferred.

[0057] The number of carbon atoms in the ether moiety of the glycol monoether is preferably 1 to 12. On the other hand, it is preferably 5 or more or 2 or less. In this case, the image quality and abrasion resistance are more excellent, which is preferable. In the case of alkyl ether or aryl ether, the ether moiety is the alkyl or aryl portion. More preferably, the ether moiety in the glycol monoether is an alkyl ether moiety, and the alkyl ether moiety has 5 or more or 2 or less carbon atoms.

[0058] Glycol monoethers having an alkyl ether moiety with 5 or more carbon atoms are more preferred. Preferably, the alkyl ether moiety has 5 or more and 12 or less carbon atoms, more preferably 6 or more and 10 or less carbon atoms, and particularly preferably 7 or more and 9 or less carbon atoms. Glycol monoethers having an alkyl ether moiety with 5 or more carbon atoms, more preferably with a carbon number within the above range, tend to have particularly excellent wet spreadability. Examples of glycol monoethers having 5 or more carbon atoms in the alkyl ether moiety include 2-ethylhexyl diglycol (also known as diethylene glycol mono 2-ethylhexyl ether, standard boiling point 272°C) and hexyl diglycol (also known as diethylene glycol monohexyl ether, standard boiling point 258°C).

[0059] Glycol monoethers having an alkyl ether moiety with 2 or less carbon atoms are more preferably glycol monoethers having an alkyl ether moiety with 1 carbon atom. Glycol monoethers having an alkyl ether moiety with 2 or less carbon atoms, more preferably 1 carbon atom, tend to have better wet spreadability, a relatively low normal boiling point, and better abrasion resistance. Examples of glycol monoethers having an alkyl ether moiety with 2 or less carbon atoms include 3-methoxy-1-butanol (standard boiling point 158°C) and 3-methoxy-3-methyl-1-butanol (standard boiling point 174°C).

[0060] Therefore, when the black ink composition contains a glycol monoether solvent, and the glycol monoether solvent has an alkyl ether moiety with 5 or more or 2 or less carbon atoms, more preferably with a carbon number within the above range, the wet spreadability and abrasion resistance tend to be further improved.

[0061] The alkylene glycol moiety in the glycol monoether preferably has 2 to 6 carbon atoms, more preferably 2 to 5 carbon atoms, further preferably 2 to 4 carbon atoms, and particularly preferably 2 to 3 carbon atoms. The number of repeating alkylene glycol moieties is preferably 1 to 5, more preferably 1 to 4, and even more preferably 1 to 3.

[0062] The "number of carbon atoms in the alkyl ether moiety" refers to, for example, the number of carbon atoms in the alkyl ether moiety in the following general formula (A): 7 The number of carbon atoms in the portion indicated by -OR 7 Part R 7 The "number of carbon atoms in the alkylene glycol moiety" is, for example, the number of carbon atoms in the alkylene glycol moiety in the following general formula (A): 6 is the number of carbon atoms in the portion indicated by

[0063] The glycol monoether solvent may also be preferably a glycol monoether represented by the following general formula (A). HO-(R 6 O) m -R 7 (A) (In general formula (A), R 6 is an alkylene group having 2 to 6 carbon atoms, and R 7 is an alkyl group having 5 or more or 2 or less carbon atoms, and m is an integer of 1 to 4.

[0064] In the above general formula (A), R 6 The alkylene group in R may be linear or branched, and preferably has 2 to 5 carbon atoms, more preferably 2 to 4 carbon atoms, and particularly preferably 2 to 3 carbon atoms. 7The alkyl group in R may be linear or branched, and preferably has 5 to 12 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 7 to 9 carbon atoms. 7 The alkyl group more preferably has 1 carbon atom. Furthermore, m is more preferably an integer of 1 to 3, and even more preferably an integer of 1 to 2.

[0065] Specific examples of glycol monoether solvents include 2-methoxyethanol (also known as ethylene glycol monomethyl ether), 2-ethoxyethanol (also known as ethylene glycol monoethyl ether), and ethylene glycol monoisopropyl ether. ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether (also known as butyl triglycol, standard boiling point 278°C), tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, 1-methoxy-2-propanol (also known as propylene glycol 1-monomethyl ether), 2-methoxypropanol (also known as propylene glycol 2-monomethyl ether), 1-ethoxy-2-propanol (also known as propylene glycol monoethyl ether), propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether Examples include diethylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, 3-methoxy-1-propanol (also known as 1,3-propanediol monomethyl ether), 1-methoxy-2-butanol (also known as 1,2-butanediol 1-monomethyl ether), 2-methoxy-1-butanol, 3-methoxy-1-butanol (also known as 1,3-butanediol 3-monomethyl ether, standard boiling point 158°C), 4-methoxy-1-butanol (also known as 1,4-butanediol monomethyl ether), 3-methoxy-3-methyl-1-butanol, 2-ethylhexyl diglycol (also known as diethylene glycol mono-2-ethylhexyl ether, standard boiling point 272°C), and hexyl diglycol (also known as diethylene glycol monohexyl ether, standard boiling point 258°C).

[0066] When a glycol monoether solvent is contained, the content thereof is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, particularly preferably 2.0% by mass or less, and more particularly preferably 1.5% by mass or less, relative to the total mass of the black ink composition. The content is also preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and more particularly preferably 0.7% by mass or more. When the content of the glycol monoether solvent is within the above range, particularly 2.0 mass % or less, the abrasion resistance is more excellent and color mixing between ink colors tends to be more reduced.

[0067] The normal boiling point of the glycol monoether solvent is preferably 300°C or lower, more preferably 100 to 280°C, and even more preferably 110 to 270°C, still more preferably 200 to 260°C, and more preferably 220 to 250°C, while it is preferably 120 to 250°C, more preferably 130 to 200°C, and even more preferably 140 to 190°C.

[0068] 1.1.4.2 Other organic solvents The black ink composition included in the ink set according to this embodiment may contain an organic solvent other than the glycol monoether solvent (other organic solvent). The other organic solvent is preferably a water-soluble organic solvent.

[0069] Examples of other organic solvents include alcohols, alkane polyols, glycol polyethers, esters, amides, sulfur-containing solvents, and cyclic ethers. The alkane polyols may include alkane diols. The organic solvents are not limited to these.

[0070] Examples of alcohols include compounds in which one hydrogen atom of an alkane is substituted with a hydroxyl group. The alkane preferably has 10 or less carbon atoms, more preferably 6 or less carbon atoms, and even more preferably 3 or less carbon atoms. The alkane has 1 or more carbon atoms, preferably 2 or more carbon atoms. The alkane may be linear or branched. Examples of alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol.

[0071] Examples of alkanediols include compounds in which an alkane is substituted with two hydroxyl groups. Examples of alkanediols include ethylene glycol (also known as ethane-1,2-diol), propylene glycol (also known as propane-1,2-diol, standard boiling point 188°C), 1,2-butanediol (standard boiling point 193°C), 1,2-pentanediol, 1,2-hexanediol (standard boiling point 223°C), 1,2-octanediol, 1,3-propanediol, 1,3-butylene glycol (also known as 1,3-butanediol, standard boiling point 207°C), 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, and 1,6-pentanediol. Examples of the hexanediol include hexanediol (standard boiling point 239°C), 2,4-pentanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol (also known as isoprene glycol), 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol (also known as hexylene glycol), 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, and 2-methyl-2-propyl-1,3-propanediol.

[0072] Examples of alkane polyols include alkane diols, condensates in which two or more molecules of alkane diols are intermolecularly condensed via the hydroxyl groups, and alkanes having three or more hydroxyl groups. The aforementioned alkane diols are also a type of alkane polyol. Alkane polyols have two or more hydroxyl groups in their molecules.

[0073] Examples of condensates in which two or more molecules of alkanediols are intermolecularly condensed via the hydroxyl groups thereof include dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylene glycols such as triethylene glycol and tripropylene glycol.

[0074] Alkanes with three or more hydroxyl groups are compounds with three or more hydroxyl groups and have a skeleton of an alkane or a polyol with a polyether structure, etc. Examples include alkanes or polyols with a polyether structure substituted with three or more hydroxyl groups. Examples of alkanes having three or more hydroxyl groups include glycerin (normal boiling point 290° C.), trimethylolethane, trimethylolpropane, 1,2,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, and polyoxypropylenetriol.

[0075] Examples of glycol polyethers include those in which two or more hydroxyl groups of the above-mentioned alkane polyols have been etherified, such as glycol diethers in which two hydroxyl groups have been etherified.Preferably, these are compounds that do not have hydroxyl groups in the molecule. Examples of etherification include alkyl ethers and aryl ethers, with alkyl ethers being preferred. The number of carbon atoms in the ether moiety of the etherification is preferably 1 to 8, more preferably 1 to 4. The number of carbon atoms in the alkylene glycol moiety of glycol polyethers is preferably 2 to 6. The number of repeating alkylene glycol moieties is preferably 1 to 5.

[0076] Specific examples of glycol diethers include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol Examples of the propylene glycol methyl butyl ether include triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol dimethyl ether.

[0077] Examples of the esters include acyclic esters and cyclic esters.

[0078] Examples of the acyclic esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and methoxybutyl acetate; Examples of glycol diesters include ethylene glycol diacetate, diethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0079] Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, and compounds in which the hydrogen atom of the methylene group adjacent to the carbonyl group of these cyclic esters is substituted with an alkyl group having 1 to 4 carbon atoms.

[0080] Examples of the amides include cyclic amides and non-cyclic amides. Examples of the non-cyclic amides include alkoxyalkyl amides.

[0081] Examples of cyclic amides include lactams, such as pyrrolidones such as 2-pyrrolidone (normal boiling point 245° C.), 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone, 2-piperidone, ε-caprolactam, N-methyl-ε-caprolactam, N-cyclohexyl-2-pyrrolidone, 5-methyl-2-pyrrolidone, β-propiolactam, ω-heptalactam, and succinimide. Among these, 2-pyrrolidone and ε-caprolactam are particularly preferred.

[0082] Examples of the acyclic amides include 3-methoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-diethylpropionamide, 3-methoxy-N,N-methylethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, 3-ethoxy-N,N-dimethylpropionamide, si-N,N-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, 3-n-butoxy-N,N-methylethylpropionamide, 3-n-propoxy-N,N-dimethylpropionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N, Examples include alkoxyalkylamides such as N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, and 3-tert-butoxy-N,N-methylethylpropionamide; N,N-dimethylacetoacetamide, N,N-diethylacetoacetamide, N-methylacetoacetamide, N,N-dimethylisobutyric acid amide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, and N,N-dimethylpropionamide.

[0083] Examples of sulfur-containing solvents include sulfoxides and sulfones. Examples of sulfoxides include acyclic sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide, and cyclic sulfoxides such as tetramethylene sulfoxide. Examples of sulfones include cyclic sulfones such as 3-methyl sulfolane and sulfolane, and acyclic sulfones such as ethyl isopropyl sulfone, ethyl methyl sulfone, and dimethyl sulfone.

[0084] Examples of cyclic ethers include tetrahydrofuran, 1,4-dioxane, dimethylisosorbide, 3-methyl-3-oxetanemethanol, 3-ethyl-3-oxetanemethanol, 2-hydroxymethyloxetane, tetrahydrofurfuryl alcohol, glycerol formal, solketal, 1,4-dioxane-2,3-diol, and dihydrolevoglucosenone.

[0085] These organic solvents may be used alone or in combination of two or more.

[0086] The normal boiling point of the organic solvent is preferably 300° C. or lower, more preferably 280° C. or lower, more preferably 270° C. or lower, even more preferably 250° C. or lower, particularly preferably 210° C. or lower, even more particularly preferably 200° C. or lower, and especially preferably 190° C. or lower. The lower limit of the normal boiling point of the organic solvent is not particularly limited, but is preferably 100° C. or higher, more preferably 110° C. or higher, more preferably 120° C. or higher, and even more preferably 150° C. or higher.

[0087] In one embodiment of the ink set according to this embodiment, the black ink composition and the chromatic color ink compositions described below each contain an organic solvent, and the content of the organic solvent having a normal boiling point of less than 200°C is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, and particularly preferably 75 parts by mass or more, per 100 parts by mass of the total organic solvents. There is no particular upper limit, but it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less. In the above embodiment, the normal boiling point is more preferably less than 195°C, and even more preferably less than 190°C. When the content of the organic solvent having a normal boiling point of less than 200° C. in the black ink composition and the chromatic color ink composition is within the above range, the black ink composition and the chromatic color ink composition tend to have excellent drying properties and excellent abrasion resistance.

[0088] In one embodiment of the ink set according to this embodiment, the black ink composition and the chromatic color ink compositions described below each contain an organic solvent, and the content of the organic solvent is preferably 1 to 40 mass %, more preferably 5 to 30 mass %, even more preferably 8 to 28 mass %, still more preferably 12 to 26 mass %, particularly preferably 15 to 24 mass %, and even particularly preferably 17 to 22 mass %, relative to the total mass of the ink composition. When the content of the organic solvent in the black ink composition and the chromatic color ink composition is within the above range, the ink composition tends to have better abrasion resistance and to be able to further reduce color mixing.

[0089] In one embodiment of the ink set according to the present embodiments, the black ink composition and the chromatic color ink compositions described below each contain an organic solvent, and the organic solvent having the highest standard boiling point among the organic solvents contained in the ink composition preferably has a standard boiling point of 300°C or less, more preferably 270°C or less, even more preferably 250°C or less, particularly preferably 230°C or less, more particularly preferably 220°C or less, especially preferably 210°C or less, even more preferably 200°C or less, and even more especially preferably 190°C or less. When the normal boiling point of the organic solvent with the highest normal boiling point among the organic solvents contained in the black ink composition and the chromatic color ink composition is within the above range, the black ink composition and the chromatic color ink composition tend to have excellent drying properties and excellent abrasion resistance.

[0090] In one embodiment of the ink set according to this embodiment, the black ink composition and the chromatic color ink compositions described below each contain preferably no more than 3% by mass of an organic solvent of an alkane polyol having a normal boiling point of greater than 280°C, more preferably no more than 2% by mass, even more preferably no more than 1% by mass, even more preferably no more than 0.5% by mass, particularly preferably no more than 0.1% by mass, and most particularly preferably no organic solvent (0% by mass). When the content of the organic solvent, an alkane polyol having a normal boiling point of more than 280°C, in the black ink composition and the chromatic color ink composition is within the above range, the drying properties of the recorded material tend to be excellent and the abrasion resistance tends to be further improved.

[0091] 1.1.5 Fixing resin The black ink composition included in the ink set according to this embodiment may further contain a fixing resin from the viewpoint of improving abrasion resistance. The fixing resin is a resin that has functions such as improving the gloss, adhesion, and stability over time of the recorded image. The fixing resin is preferably contained in the ink in the form of an emulsion or powder, i.e., in the form of resin particles.

[0092] The resin particles are not particularly limited, but examples thereof include resin particles made of urethane resins, acrylic resins (including styrene-acrylic resins), fluorene resins, polyolefin resins, rosin-modified resins, terpene resins, polyester resins, polyamide resins, epoxy resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, ethylene vinyl acetate resins, and the like.

[0093] Urethane resin is a general term for resins having urethane bonds. In addition to urethane bonds, the urethane resin may be a polyether urethane resin containing ether bonds in the main chain, a polyester urethane resin containing ester bonds in the main chain, or a polycarbonate urethane resin containing carbonate bonds in the main chain.

[0094] Acrylic resin is a general term for polymers obtained by polymerizing at least acrylic monomers such as (meth)acrylic acid and (meth)acrylic acid esters as one component. For example, it includes resins obtained from acrylic monomers and copolymers of acrylic monomers with other monomers. Examples include acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers. Another example of a vinyl monomer is styrene. Acrylamide, acrylonitrile, and the like can also be used as the acrylic monomer. In this specification, the term "(meth)acrylic" means at least one of acrylic and methacrylic.

[0095] The polyolefin resin has an olefin such as ethylene, propylene, or butylene in its structural skeleton, and any known polyolefin resin can be appropriately selected and used.

[0096] The resin particles may be used alone or in combination of two or more.

[0097] Among these, acrylic resin particles, urethane resin particles, or polyester resin particles are preferred. The use of such resin particles tends to further improve abrasion resistance. These resin particles are often handled in the form of an emulsion, but may also be in the form of a powder.

[0098] As the resin particles, acrylic resins are particularly preferred, and styrene-acrylic resins are more preferred. The styrene-acrylic resins are not particularly limited, but examples thereof include styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers. By using such resins, the abrasion resistance of the resulting recorded matter tends to be further improved.

[0099] The content of the resin particles is preferably 0.5 to 6.0% by mass, more preferably 1.0 to 5.0% by mass, and even more preferably 2.0 to 4.0% by mass, relative to the total mass of the black ink composition. When the content of the resin particles is within this range, abrasion resistance tends to be further improved.

[0100] 1.1.6 Wax The black ink composition included in the ink set according to this embodiment may further contain wax from the viewpoint of improving abrasion resistance.

[0101] The wax is not particularly limited, but examples thereof include hydrocarbon waxes and ester waxes, which are condensates of fatty acids with monohydric alcohols or polyhydric alcohols. The hydrocarbon wax is not particularly limited, but examples thereof include paraffin waxes and polyolefin waxes such as polyethylene waxes and polypropylene waxes. These waxes may be used alone or in combination of two or more. Among these waxes, from the viewpoint of improving abrasion resistance, hydrocarbon waxes are preferred, polyolefin waxes are more preferred, and polyethylene waxes are even more preferred.

[0102] The wax may be in the form of an emulsion, for example, in which wax particles are dispersed in water.

[0103] The wax content is preferably 0.1 to 5.0% by mass, more preferably 0.3 to 3.0% by mass, and even more preferably 0.6 to 1.5% by mass, relative to the total amount of the black ink composition, which tends to further improve the abrasion resistance of the resulting recorded matter.

[0104] 1.1.7 Other ingredients The black ink composition provided in the ink set according to this embodiment may also contain various additives, such as a dissolution aid, a viscosity adjuster, a pH adjuster, an antioxidant, a preservative, an antifungal agent, a corrosion inhibitor, and a chelating agent, as appropriate.

[0105] 1.2 Chromatic Ink Composition The chromatic color ink compositions included in the ink set according to this embodiment are water-based inkjet inks that contain at least a colorant and a specific silicone surfactant 1. In addition to the components described below, the chromatic color ink compositions may also preferably contain the same types and amounts of components as may be contained in the black ink composition described above.

[0106] In the present invention, "chromatic color" refers to, for example, color tones such as cyan, magenta, yellow, red, green, orange, and blue. * a * b * In the color space, a * , b * It is a color that has a value, a hue, and a saturation. On the other hand, "achromatic colors" refer to colors that are perceived as black or white. They are colors that have no hue or saturation.

[0107] 1.2.1 Colorants The chromatic color ink compositions included in the ink set according to this embodiment contain a colorant. The colorant may be either a pigment or a dye, and examples of the colorant include inorganic pigments such as titanium white, organic pigments, oil-soluble dyes, acid dyes, direct dyes, reactive dyes, basic dyes, disperse dyes, and sublimation dyes. The aforementioned black colorant may also be used if necessary.

[0108] Examples of inorganic pigments other than the above-mentioned black pigment include iron oxide, titanium oxide, zinc oxide, and silica.

[0109] Examples of organic pigments include quinacridone pigments, quinacridonequinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments.

[0110] Specific examples of organic pigments include the following:

[0111] Examples of cyan pigments include CI Pigment Blue 1, 2, 3, 15:3, 15:4, 15:34, 16, 22, 60, etc.; CI Vat Blue 4, 60, etc., and preferably, one or a mixture of two or more selected from the group consisting of CI Pigment Blue 15:3, 15:4, and 60 can be exemplified.

[0112] Examples of magenta pigments include CI Pigment Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122, 123, 168, 184, 202, and CI Pigment Violet 19. Preferred examples include one or a mixture of two or more pigments selected from the group consisting of CI Pigment Red 122, 202, and 209, and CI Pigment Violet 19.

[0113] Yellow pigments include CI Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, and 185. and preferably, one or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, 138, 150, and 180 can be exemplified.

[0114] Pigments of other colors can also be used, such as orange pigments and green pigments.

[0115] Examples of dyes other than the above-mentioned black dyes include CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 132, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, and CI Reactive Red 14, 32, 55, 79, 141, 249.

[0116] The content of the colorant can be adjusted as appropriate depending on the application, but is preferably from 0.1% by mass to 17.0% by mass, more preferably from 0.2% by mass to 15.0% by mass, even more preferably from 1.0% by mass to 10.0% by mass, and particularly preferably from 2.0% by mass to 5.0% by mass, relative to the total mass of the chromatic color ink composition.

[0117] 1.2.2 Water The chromatic color ink compositions included in the ink set according to this embodiment are water-based inkjet inks that contain water.

[0118] The water content is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, particularly preferably 55% by mass or more, more particularly preferably 60% by mass or more, and especially preferably 65% ​​by mass or more, relative to the total mass of the chromatic color ink composition. There is no particular upper limit for the water content, but it is preferably 90% by mass or less, more preferably 80% by mass or less, relative to the total mass of the chromatic color ink composition.

[0119] 1.2.3 Surfactants The chromatic color ink compositions provided in the ink set according to this embodiment contain a silicone surfactant 1 (specific silicone surfactant 1) that has a maximum peak in the molecular weight range of 300 or more in the range of 3,000 to 20,000 in the molecular weight distribution measured by gel permeation chromatography.

[0120] When the chromatic color ink composition contains the specific silicone-based surfactant 1, it is possible to significantly reduce intercolor mixing between the black ink composition and the chromatic color ink composition. This is presumably because the specific silicone-based surfactant 1 has a relatively high molecular weight and acts to block other ink droplets from penetrating into ink droplets containing this component, but the reason is not limited to this. It is also preferable in terms of suppressing aggregation unevenness in the image. In particular, if the black ink composition contains the specific silicone surfactant 2 described above, inter-color mixing between the black ink composition and the chromatic color ink composition tends to be more effectively suppressed, which is preferable.

[0121] 1.2.3.1 Certain silicone surfactants1 The maximum peak in the range of molecular weight of 300 or more of specific silicone surfactant 1 is a molecular weight of 3,000 to 20,000, preferably a molecular weight of 4,000 to 15,000, and more preferably a molecular weight of 5,000 to 10,000. When the maximum peak in the range of molecular weight of 300 or more is a molecular weight of 3,000 or more, the black ink composition and the chromatic ink composition can be easily combined. Inter-color mixing of the ink composition is suppressed, and image quality (border bleeding) tends to be improved. By keeping the maximum peak in the range of molecular weight 300 or more to a molecular weight of 20,000 or less, ejection stability tends to be improved.

[0122] The specific silicone surfactant 1 is not particularly limited, but examples thereof include polysiloxane compounds such as dimethylsiloxane, methylphenylsiloxane, and diphenylsiloxane. These polysiloxane compounds may also be modified organosiloxanes in which terminal or side chain groups have been modified with polyether groups, etc. These specific silicone surfactants 1 may be used alone or in combination of two or more.

[0123] Among these, the specific silicone surfactant 1 is preferably a modified organosiloxane, and more preferably a polyether-modified organosiloxane. Examples of such polyether-modified organosiloxanes include modified organosiloxanes whose terminals are modified with polyether groups, as shown in the following general formula (1), and modified organosiloxanes whose side chains are modified with polyether groups, as shown in the following general formula (3). Use of such specific silicone surfactant 1 tends to further suppress intercolor mixing between the black ink composition and the chromatic color ink compositions. Among the specific silicone surfactants 1, the modified organosiloxane whose terminals are modified with polyether groups, as shown in the following general formula (1), is particularly preferred for its superior suppression of intercolor mixing and aggregation unevenness in inks.

[0124] [ka] (In general formula (1), R 1 each independently represents an alkylene group having 1 to 6 carbon atoms or a single bond; X 1 each independently represents a polyether group represented by the following general formula (2), and a is an integer of 10 or more and 80 or less.

[0125] [ka] (In general formula (2), R 2 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a (meth)acrylic group; EO represents an ethylene oxide group; PO represents a propylene oxide group; (EO) b and (PO)c The order of is unspecified, b is an integer greater than or equal to 0, and c is an integer greater than or equal to 0, provided that b+c is an integer greater than or equal to 1.)

[0126] [ka] (In general formula (3), R 3 each independently represents an alkyl group having 1 to 6 carbon atoms; X 2 each independently represents a polyether group represented by the following general formula (4), where d and e are integers of 1 or more, and d+e is an integer of 2 or more and 50 or less.

[0127] [ka] (In general formula (4), R 4 represents an alkylene group having 1 to 6 carbon atoms or a single bond, and R 5 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, EO represents an ethylene oxide group, PO represents a propylene oxide group, (EO) f and (PO) g The order of is unspecified, f is an integer greater than or equal to 0, and g is an integer greater than or equal to 0, provided that f+g is an integer greater than or equal to 1.)

[0128] R 1 , R 3 , and R 4 The alkylene group having 1 to 6 carbon atoms represented by the formula (R) is not particularly limited, but examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group. 1 , R 4 is preferably an alkylene group having 1 to 6 carbon atoms.

[0129] R 2 and R 5The alkyl group having 1 to 6 carbon atoms, represented by the formula (I), is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, a neopentyl group, and an n-hexyl group.

[0130] R 1 , R 4 may be a single bond. A single bond is 1 , R 4 This indicates that the atom on the right and the atom on the left are directly connected by a single bond.

[0131] In the above general formulas (1) and (2), a is an integer of 10 or more and 80 or less, preferably an integer of 20 or more and 70 or less, and more preferably an integer of 30 or more and 60 or less. Furthermore, b is an integer of 0 or more, preferably an integer of 2 or more and 30 or less, and more preferably an integer of 5 or more and 20 or less. Furthermore, c is an integer of 0 or more, preferably an integer of 0 or more and 30 or less, and more preferably an integer of 0 or more and 20 or less. Furthermore, b+c is an integer of 1 or more, preferably an integer of 1 or more and 60 or less, more preferably an integer of 2 or more and 40 or less, and even more preferably an integer of 5 or more and 20 or less.

[0132] In the above general formulas (3) and (4), d and e are each an integer of 1 or greater, preferably 5 or greater and 40 or less, and more preferably 10 or greater and 20 or less. d+e is an integer of 2 or greater and 50 or less, preferably 5 or greater and 40 or less, and more preferably 10 or greater and 30 or less. f is an integer of 0 or greater, preferably 1 or greater, even more preferably 2 or greater and 30 or less, and more preferably 5 or greater and 20 or less. g is an integer of 0 or greater, preferably 0 or greater and 30 or less, and more preferably 0 or greater and 20 or less. f+g is an integer of 1 or greater, preferably 1 or greater and 60 or less, more preferably 2 or greater and 40 or less, and even more preferably 5 or greater and 20 or less.

[0133] Alternatively, the specific silicone surfactant 1 may be a commercially available product, such as BYK-333 (trade name of BYK Japan, the maximum peak in the molecular weight range of 300 or more in the molecular weight distribution measured by GPC is 6,760) or BYK-3480 (trade name of BYK Japan, the maximum peak in the molecular weight range of 300 or more in the molecular weight distribution measured by GPC is 4,330).

[0134] The content of specific silicone surfactant 1 is preferably 0.05% by mass or more relative to the total mass of the chromatic ink composition. It is further preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and particularly preferably 0.4% by mass or more. On the other hand, it is preferably 5.0% by mass or less relative to the total mass of the chromatic ink composition, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less, even particularly preferably 0.7% by mass or less, and even more preferably 0.6% by mass or less. It is further preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, and more preferably 0.2% by mass or less. When the content of the specific silicone surfactant 1 in the chromatic color ink composition is within the above range, there is a tendency for the prevention of inter-color mixing of inks and the image quality of the chromatic color ink composition to be improved in a balanced manner.

[0135] 1.2.3.2 Other surfactants The chromatic color ink compositions included in the ink set according to this embodiment may contain a surfactant other than the above-described specific silicone surfactant 1. Examples of such surfactants include the surfactants that can be contained in the black ink composition described above, in particular the specific silicone surfactant 2. The specific silicone surfactant 2 may be the same as or different from the specific silicone surfactant 2 that can be contained in the above-described black ink composition.

[0136] In the chromatic ink composition, the specific silicone surfactant 2 is present in an amount of 0% by mass or greater, preferably 0.05% by mass or greater, relative to the total mass of the ink. It is preferably 0.1% by mass or greater, more preferably 0.2% by mass or greater, even more preferably 0.3% by mass or greater, and particularly preferably 0.4% by mass or greater. The upper limit is preferably 5.0% by mass or less, more preferably 2.0% by mass or less, even more preferably 1.0% by mass or less, particularly preferably 0.8% by mass or less, even particularly preferably 0.7% by mass or less, and even more preferably 0.6% by mass or less, relative to the total mass of the chromatic ink composition. It is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less. It is preferable that the chromatic color ink composition does not contain the specific silicone surfactant 2. When the content of the specific silicone surfactant 2 is within the above range, the chromatic color ink composition tends to have good wetting and spreading properties.

[0137] In the chromatic color ink compositions provided in the ink set according to this embodiment, the total content of silicone surfactants, including specific silicone surfactants 1 and 2, is preferably at least 0.05% by mass, more preferably at least 0.1% by mass, even more preferably at least 0.3% by mass, even more preferably at least 0.5% by mass, particularly preferably at least 0.8% by mass, even more particularly preferably at least 1.0% by mass, and especially preferably at least 1.3% by mass. The upper limit is preferably at most 6.0% by mass, more preferably at most 4.0% by mass, even more preferably at most 2.0% by mass, particularly preferably at most 1.7% by mass, even more particularly preferably at most 1.5% by mass, and especially preferably at most 1.3% by mass, relative to the total mass of the chromatic color ink compositions.

[0138] Furthermore, the total content of silicone surfactants in the chromatic ink compositions is preferably greater than the total content of silicone surfactants in the black ink composition, as this relationship tends to better prevent inter-color ink mixing.

[0139] 1.2.4 Organic solvents The chromatic color ink compositions included in the ink set according to this embodiment may contain an organic solvent. The type and content of the organic solvent that can be used may be the same as those for the black ink composition described above, but it should be noted that the organic solvent can be prepared independently of the black ink composition.

[0140] The chromatic color ink composition particularly preferably contains a glycol monoether solvent, which tends to improve the wetting and spreading properties of the ink, further reduce inter-color mixing of the ink, and also provide excellent abrasion resistance.

[0141] When a glycol monoether solvent is contained, the content thereof is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, even more preferably 3.0% by mass or less, particularly preferably 2.0% by mass or less, and more particularly preferably 1.5% by mass or less, relative to the total mass of the chromatic color ink composition. The content is also preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and more particularly preferably 0.7% by mass or more. When the content of the glycol monoether solvent is within the above range, particularly 2.0 mass % or less, the abrasion resistance is more excellent and color mixing between ink colors tends to be more reduced.

[0142] 1.2.5 Fixing resin The chromatic color ink compositions included in the ink set according to this embodiment may contain a fixer resin. The type and content of the fixer resin that can be used may be the same as those for the black ink composition described above, but it should be noted that the fixer resin can be prepared independently of the black ink composition.

[0143] 1.2.6 Wax The chromatic color ink compositions included in the ink set according to this embodiment may contain wax. The type and content of wax that can be used may be the same as those for the black ink composition described above, but it should be noted that the wax can be prepared independently of the black ink composition.

[0144] 1.2.7 Other ingredients The chromatic color ink compositions provided in the ink set according to this embodiment may also contain various additives, such as a solubilizing agent, a viscosity adjusting agent, a pH adjusting agent, an antioxidant, a preservative, an antifungal agent, a corrosion inhibitor, and a chelating agent, as appropriate.

[0145] 1.3 Method for preparing ink composition The method for preparing the black ink composition and the chromatic color ink composition is not particularly limited, but examples include a method in which the above-mentioned components are mixed and stirred sufficiently so that the components are uniformly mixed.

[0146] 1.4 Application The ink set according to this embodiment is used for recording on low-absorbency recording media or non-absorbency recording media, and the recording method described below can be applied to the recording mode.

[0147] A non-absorbent recording medium or a low-absorbent recording medium refers to a recording medium that does not absorb liquid such as ink at all or absorbs very little of it. Quantitatively, a non-absorbent recording medium or a low-absorbent recording medium is a recording medium that absorbs ink within 30 msec from the start of contact in the Bristow method. 1 / 2 Water absorption up to 10mL / m 2 This refers to the recording medium described below. The Bristow method is the most widely used method for measuring the amount of liquid absorption in a short period of time, and is also adopted by the Japan Pulp and Paper Technical Association (JAPAN TAPPI). Details of the test method are described in Standard No. 51 "Paper and Paperboard - Liquid Absorbency Test Method - Bristow Method" of "JAPAN TAPPI Paper and Pulp Test Method 2000 Edition." In contrast, absorbent recording media refers to recording media that do not fall under the category of non-absorbent or low-absorbent.

[0148] Non-absorbent recording media include those whose recording surface contains plastic, and more preferably those whose recording surface is made of plastic. Here, the surface of the recording surface does not have an absorption layer or a receiving layer for absorbing liquid. For example, those in which plastic is coated on a substrate such as paper, those in which a plastic film is adhered to a substrate such as paper, and plastic films without an absorption layer or a receiving layer are included. Examples of plastics referred to here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc.

[0149] The low-absorbency recording medium may be a recording medium called coated paper, which has a coating layer on its surface. For example, when the substrate is paper, printing paper such as art paper, coated paper, or matte paper may be used. When the substrate is a plastic film, the substrate may be polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, or polypropylene, coated with a hydrophilic polymer or the like, or coated with particles of silica, titanium, or the like together with a binder.

[0150] The recording medium may be colorless and transparent, semi-transparent, colored and transparent, colored and opaque, colorless and opaque, or the like.

[0151] 2. Recording method A recording method according to an embodiment of the present invention includes: A recording method for recording on a low-absorbency recording medium or a non-absorbency recording medium using the ink set described above, a black ink applying step of applying the black ink composition to the recording medium by an inkjet method; and a chromatic ink applying step of applying the chromatic ink composition to the recording medium by an ink jet method.

[0152] According to the recording method of this embodiment, by using the ink set described above, the black ink has excellent wettability and spreadability on the recording medium, resulting in excellent color development (OD value) of the black image, and also reducing color mixing between the black ink and color inks, resulting in excellent image quality (border bleeding).

[0153] The low-absorbency recording medium or non-absorbency recording medium may be the same as the recording medium used in the ink set described above.

[0154] 2.1 Black ink application process and chromatic ink application process The recording method according to this embodiment comprises a black ink applying step of applying the black ink composition included in the ink set described above to a recording medium by an inkjet method, and a chromatic color ink applying step of applying the chromatic color ink compositions included in the ink set described above to a recording medium by an inkjet method.

[0155] The inkjet method is a recording method in which minute droplets of inkjet ink are ejected from ejection nozzles of an inkjet head provided in a recording device such as an inkjet printer, and are made to adhere to a recording medium or the like.

[0156] The black ink application step and the chromatic color ink application step can be easily carried out, for example, by using an inkjet recording apparatus 1 shown in Fig. 1, which is an embodiment of an inkjet recording apparatus described below, to eject ink from an inkjet head 2. Note that a composition used for recording by ejecting ink from an inkjet head using an inkjet method is called an inkjet ink.

[0157] The order of the black ink application step and the chromatic color ink application step is not particularly limited, and the chromatic color ink application step may be performed before the black ink application step, the chromatic color ink application step may be performed after the black ink application step, or the chromatic color ink application step may be performed simultaneously with the black ink application step.

[0158] The amount of the black ink composition and the chromatic color ink composition applied is 1 to 40 mg / inch per unit area of ​​the recording region of the recording medium. 2 is preferably 2 to 30 mg / inch 2 More preferably, it is 4 to 20 mg / inch. 2 More preferably, it is 6 to 16 mg / inch. 2 It is particularly preferable that the maximum amount of ink adhered per unit area of ​​the recording region of the recording medium during recording be within the above range. Note that the amount of ink adhered can be adjusted independently for each ink composition.

[0159] Furthermore, in the black ink application step and the chromatic color ink application step of the recording method according to this embodiment, it is preferable that main scans are performed multiple times, in which the relative position of the recording medium and the inkjet head is moved while the ink composition is being ejected from the inkjet head, and the number of main scans performed in the same main scanning region is preferably 10 or less. The upper limit of the number of main scans performed in the same main scanning region is more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. The lower limit is 1 or more, and is not particularly limited, but is preferably 2 or more, and more preferably 3 or more.

[0160] The term "main scan" refers to the operation of ejecting an ink composition from the inkjet head and depositing it on the recording medium while moving the position of the inkjet head relative to the recording medium. The inkjet head can be mounted on, for example, a carriage. The inkjet head may also be moved by moving the carriage, in which case, the movement is also referred to as the movement of the inkjet head. Furthermore, when recording on a given area, the number of times the inkjet head passes over that area is referred to as the "number of passes." For example, if four main scans are performed over the same area to deposit the ink composition, the number of passes is referred to as four passes.

[0161] In the main scanning, the time for one main scanning pass is preferably 0.5 to 5 seconds, more preferably 1 to 4 seconds, and even more preferably 2 to 3 seconds. The time for one main scanning pass (also referred to as the main scanning time) is the time required for the head to move from a position facing one edge of the recording medium to a position facing the other edge of the recording medium in one main scanning pass.

[0162] The black ink application step and the chromatic color ink application step may be performed so that the surface temperature of the recording medium is 60° C. or less when the black ink composition and the chromatic color ink composition are applied to the recording medium. That is, the black ink application step and the chromatic color ink application step may be performed without heating the recording medium, or may be performed with heating. Even when heating is performed, it is preferable to heat the recording medium so that the surface temperature is 60° C. or less. The upper limit of the surface temperature of the recording medium during ink adhesion is more preferably 50° C. or less, even more preferably 45° C. or less, particularly preferably 40° C. or less, even more particularly preferably 35° C. or less, and especially preferably 28° C. or less. On the other hand, the lower limit is preferably 20° C. or more, more preferably 23° C. or more, and particularly preferably 25° C. or more. Furthermore, 28° C. or more is more preferably 35° C. or more, and even more preferably 40° C. or more.

[0163] 2.2 Primary drying process The recording method according to this embodiment may further include a primary drying step of drying the black ink composition and the chromatic color ink compositions that have been applied to the recording medium. By including such a step, the drying properties of the inks can be improved at an early stage after the ink compositions have been applied to the recording medium, and color mixing between the inks tends to be further reduced.

[0164] The primary drying step is a step of drying the ink at an early stage after the ink composition is applied to a recording medium. The primary drying step is a drying step for drying at least a portion of the ink solvent component of the ink applied to the recording medium to at least an extent that reduces the ink flow. It is preferable that the ink droplets that land on the recording medium begin to be dried in the primary drying step within 0.5 seconds at the latest after the ink droplets land on the recording medium.

[0165] Examples of means for the primary drying step include an air blowing method, which involves blowing room-temperature air (room-temperature air) or heated air (hot air) onto the recording medium using a fan or the like; a heat transfer method based on heating the recording medium using an IR heater, microwave radiation, or platen heater; and a combination of these methods. Note that the primary drying step in this embodiment is not particularly limited as long as it can improve the drying properties of the ink, and does not necessarily require heating. Therefore, in the primary drying step in this embodiment, a method based on room-temperature air blowing may be used alone. It is more preferable that the primary drying step be a method that involves heating.

[0166] When drying by air blowing is performed in the primary drying step, the air blowing speed is preferably 0.5 to 15 m / s, more preferably 0.5 to 10 m / s, even more preferably 1 to 5 m / s, and particularly preferably 2 to 3 m / s. The air speed is the air speed near the surface of the recording medium. When the air speed is within the above range, color mixing between inks tends to be further reduced. The temperature of the blown air is preferably 50° C. or lower, and preferably 10° C. or higher. It is further preferably 15 to 45° C., and more preferably 20 to 49° C. It is further preferably 23 to 40° C., more preferably 25 to 35° C., and even more preferably 25 to 28° C. The temperature of the blown air may be room temperature.

[0167] Furthermore, the surface temperature of the recording medium in the primary drying step may be within the range of temperatures described above as the surface temperature of the recording medium in the black ink application step and the chromatic color ink application step, and is therefore preferred. That is, the surface temperature of the recording medium in the primary drying step is particularly preferably 45° C. or less, and more preferably within the above-mentioned surface temperature range. According to the recording method of this embodiment, drying can be carried out even under conditions of the relatively low temperature range described above, which is preferable because it is possible to achieve a good balance between the prevention of inter-color mixing of the ink, wet spreadability, and abrasion resistance.

[0168] If heating is involved in the primary drying step, the ink may be applied to a heated recording medium, or the recording medium may be heated immediately after application. Preferably, the primary drying step begins within 0.5 seconds at the latest after the ink droplets land on the recording medium. When heating is involved in the primary drying step, the heating may be carried out at least either before, simultaneously with, or shortly after the black ink and chromatic color ink application steps described above, and is preferably carried out simultaneously. The black ink application step and the chromatic color ink application step can be carried out in this heating order.

[0169] The surface temperature of the recording medium in the primary drying step is the surface temperature of the recording medium at the time of ink deposition when the ink is deposited on the recording medium after the primary drying step has been performed, and is the surface temperature of the recording medium at the time of the primary drying step when the ink is deposited on the recording medium after the primary drying step has been performed. It is also the maximum temperature during the primary drying process. The surface temperature of the recording medium during the primary drying process is preferably within the range of the surface temperature of the recording medium when the ink is applied. Furthermore, the surface temperature of the recording medium when no heating is performed in the primary drying step is the surface temperature of the recording medium when the ink is attached.

[0170] 2.3 Post-drying process The recording method according to this embodiment may also include a post-drying step in which the surface of the recording medium to which the black ink composition and the chromatic color ink compositions have been attached is heated after passing through a platen, preferably at 60 to 120° C., more preferably 70 to 110° C., and even more preferably 80 to 100° C. This is preferable because it tends to improve the drying properties and produce a recorded product with better abrasion resistance.

[0171] The post-drying process is a process for completing the recording and drying the recorded matter sufficiently to enable it to be used. The post-drying process is a drying process for sufficiently drying the solvent component of the ink and for heating the fixing resin that may be contained in the ink to form a flat ink coating film.

[0172] The post-drying step is preferably initiated on the surface of the recording medium including a certain point on the recording medium to which ink has been applied in the black ink application step and the chromatic color ink application step described above, after the certain point has passed the platen. For example, in the inkjet recording apparatus 1 shown in Figures 1 and 2, ink is applied to a certain point on the recording medium M by the inkjet head 2 facing the platen 11, and after the certain point on the recording medium M to which ink has been applied has passed the platen 11, the post-drying step is initiated on the surface of the recording medium M including the certain point by the heater 5.

[0173] The heating of the recording medium in the post-drying step can be carried out using an appropriate heating means, for example, when an inkjet recording apparatus is used, and can also be carried out by any appropriate heating means, not limited to the heating means provided in the inkjet recording apparatus.

[0174] In the post-drying step, the lower limit of the surface temperature of the recording medium is preferably 50° C. or higher, more preferably 60° C. or higher, even more preferably 70° C. or higher, and particularly preferably 75° C. or higher. The upper limit of the surface temperature of the recording medium is preferably 120° C. or lower, more preferably 110° C. or lower, even more preferably 100° C. or lower, and particularly preferably 90° C. or lower. It is preferable that the temperature preferred in the primary drying step is different from the temperature preferred in the post-drying step.

[0175] 2.4 Inkjet recording device An example of an inkjet recording apparatus that can be used in the recording method according to this embodiment will be described with reference to the drawings.

[0176] FIG. 1 is a schematic cross-sectional view showing an inkjet recording apparatus. FIG. 2 is a perspective view showing an example of the configuration of the periphery of the carriage of the inkjet recording apparatus 1 of FIG. 1. As shown in FIGS. 1 and 2, the inkjet recording apparatus 1 includes an inkjet head 2, an IR heater 3, a platen heater 4, a heating heater 5, a cooling fan 6, a preheater 7, a ventilation fan 8, a carriage 9, a platen 11, a carriage movement mechanism 13, a transport means 14, and a control unit CONT. The operation of the entire inkjet recording apparatus 1 is controlled by the control unit CONT shown in FIG. 2.

[0177] The inkjet head 2 ejects the black ink composition and the chromatic ink composition. In this embodiment, the inkjet head 2 is a serial inkjet head that scans multiple times in the main scanning direction relative to the recording medium M to deposit ink on the recording medium M. The inkjet head 2 is mounted on a carriage 9 shown in FIG. 2. The inkjet head 2 is scanned multiple times in the main scanning direction relative to the recording medium M by the operation of a carriage movement mechanism 13 that moves the carriage 9 in the medium width direction of the recording medium M. The medium width direction is the main scanning direction of the inkjet head 2. Scanning in the main scanning direction is also called main scanning.

[0178] Here, the main scanning direction is the direction in which the carriage 9 carrying the inkjet head 2 moves. In FIG. 1, this direction intersects with the sub-scanning direction, which is the transport direction of the recording medium M, indicated by the arrow SS. In FIG. 2, the width direction of the recording medium M, i.e., the direction indicated by S1-S2, is the main scanning direction MS, and the direction indicated by T1→T2 is the sub-scanning direction SS. Note that scanning is performed in the main scanning direction, i.e., in either the direction indicated by the arrow S1 or the arrow S2, in one scan. Recording is performed on the recording medium M by repeatedly performing the main scan of the inkjet head 2 and the sub-scan, which transports the recording medium M, multiple times. In other words, the black ink application process and the chromatic color ink application process are performed by multiple main scans in which the inkjet head 2 moves in the main scanning direction and multiple sub-scans in which the recording medium M moves in the sub-scanning direction that intersects the main scanning direction.

[0179] The cartridges 12 that supply each ink composition to the inkjet head 2 include a plurality of independent cartridges. The cartridges 12 are detachably mounted on a carriage 9 that mounts the inkjet head 2. A different type of ink composition can be filled in each of the plurality of cartridges, and the ink composition is supplied from the cartridges 12 to each nozzle. Note that, although this embodiment shows an example in which the cartridge 12 is mounted on the carriage 9, this is not limiting, and the cartridge 12 may be provided in a location other than the carriage 9, and ink may be supplied to each nozzle by a supply pipe (not shown).

[0180] A conventionally known method can be used for ejection from the inkjet head 2. In this embodiment, a method of ejecting droplets using the vibration of a piezoelectric element, that is, an ejection method of forming ink droplets by mechanical deformation of an electrostrictive element, is used.

[0181] The inkjet recording apparatus 1 is equipped with a ventilation fan 8, an IR heater 3, and a platen heater 4 for drying the ink composition ejected from the inkjet head 2 and attached to the recording medium M. The primary drying step can be carried out by using an appropriate combination of the ventilation fan 8, the IR heater 3, and the platen heater 4. In the primary drying step, it is not always necessary to heat the recording medium M, and the ventilation fan 8 may be used alone to blow air at room temperature.

[0182] Note that by using the IR heater 3, the recording medium M can be radiatively heated by radiating infrared rays from the inkjet head 2 side. This makes it easier for the inkjet head 2 to be heated at the same time, but compared to heating from the back side of the recording medium M using a platen heater 4 or the like, the temperature can be increased without being affected by the thickness of the recording medium M. Also, various fans (for example, ventilation fan 8) may be provided to blow warm air or air at the same temperature as the environment onto the recording medium M to dry the ink on the recording medium M.

[0183] The platen heater 4 can heat the recording medium M via the platen 11 at a position opposite the inkjet head 2 so that the ink composition ejected by the inkjet head 2 can be dried quickly from the time it is applied to the recording medium M. The platen heater 4 can heat the recording medium M by conduction. In the recording method, the ink composition can be adhered to the heated recording medium M. Therefore, the ink composition can be fixed on the recording medium M at an early stage, thereby improving image quality.

[0184] The heater 5 dries and solidifies the ink composition applied to the recording medium M, i.e., it is a heater for secondary heating or secondary drying. The heater 5 can be used in a post-drying process. When the heater 5 heats the recording medium M on which an image has been recorded, the moisture and other components contained in the ink composition evaporate and dissipate more quickly, and an ink film is formed by the fixing resin that may be contained in the ink composition. In this way, the ink film is firmly fixed or adhered to the recording medium M, resulting in excellent film-forming properties and allowing an excellent, high-quality image to be obtained in a short period of time.

[0185] The inkjet recording apparatus 1 may have a cooling fan 6. After the ink composition recorded on the recording medium M is dried, the ink composition on the recording medium M is cooled by the cooling fan 6, whereby an ink coating film with good adhesion can be formed on the recording medium M.

[0186] The inkjet recording apparatus 1 may also include a preheater 7 that preheats the recording medium M before the ink composition is applied to the recording medium M. Furthermore, the inkjet recording apparatus 1 may also include a ventilation fan 8 so that the ink composition applied to the recording medium M dries more efficiently.

[0187] Below the carriage 9, there are provided a platen 11 that supports the recording medium M, a carriage movement mechanism 13 that moves the carriage 9 relative to the recording medium M, and a conveying means 14 that is a roller that conveys the recording medium M in the sub-scanning direction. The operations of the carriage movement mechanism 13 and the conveying means 14 are controlled by a control unit CONT.

[0188] 1 and 2, a serial type inkjet recording device is shown, but a line type inkjet recording device can also be used. The inkjet recording apparatus exemplified above can be preferably used to implement the recording method according to this embodiment.

[0189] 3. Working Example The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" below is based on mass.

[0190] 3.1 Preparation of ink composition The components were placed in a container to obtain the compositions shown in Tables 1 to 3 below, mixed and stirred for two hours using a magnetic stirrer, and then filtered through a membrane filter with a pore size of 5 μm, thereby obtaining black ink compositions and chromatic color ink compositions according to Examples and Comparative Examples. The numerical values ​​for amounts in Tables 1 to 3 below indicate mass %, and ion-exchanged water was added so that the total mass of the ink composition was 100 mass %. The colorant was previously mixed with a water-soluble styrene-acrylic resin dispersant in a pigment:dispersant ratio of 2:1 by mass and stirred to prepare a pigment dispersion, which was then used to prepare the ink compositions. The colorant, fixing resin, and wax in the tables indicate the amount of active ingredient (equivalent to solids).

[0191] [Table 1]

[0192] [Table 2]

[0193] [Table 3]

[0194] The following provides additional explanations for the descriptions in Tables 1 to 3 above. <Terminology> "Silicone surfactant 1": Silicone surfactant 1 having a maximum peak in the range of molecular weight 300 or more in the range of 3,000 to 20,000 in the molecular weight distribution measured by gel permeation chromatography. "Silicone surfactant 2": Silicone surfactant 2 having a maximum peak in the range of 300 to 1,500 in the molecular weight distribution of 300 or more in the range of molecular weight by gel permeation chromatography. "Solvent ratio below 200°C bp": The ratio of the content (mass%) of organic solvents with a standard boiling point of less than 200°C to the total amount (mass%) of organic solvents "Total amount of silicone surfactants": The total amount of silicone surfactant 1, silicone surfactant 2, and other silicone surfactants

[0195] <Ingredients> -Coloring materials- "PB15:3": CI Pigment Blue 15:3 -Fixing resin- "Joncryl 537": Styrene-acrylic resin particles, manufactured by BASF -wax- "AQUACER539": Polyethylene wax, manufactured by BYK Japan -Silicone surfactant 1- "BYK333": Manufactured by BYK Japan. In the molecular weight distribution measured by GPC, the maximum peak in the range of molecular weight 300 or more is 6,760 "BYK3480": Manufactured by BYK Japan. In the molecular weight distribution measured by GPC, the maximum peak in the range of molecular weight 300 or more is 4,330. -Silicone surfactant 2- "BYK349": Manufactured by BYK Japan. In the molecular weight distribution measured by GPC, the maximum peak in the range of molecular weight 300 or more is 1,470 "Surfactant prepared by Preparation Example 1": In the molecular weight distribution measured by GPC, the maximum peak in the range of molecular weight 300 or more is 950 -Other silicone surfactants- "SAG503A": Manufactured by Nissin Chemical Industry Co., Ltd. - Glycol monoether solvent - "EHDG (2-ethylhexyl diglycol)": Also known as diethylene glycol mono 2-ethylhexyl ether "HeDH (hexyl diglycol)": Also known as diethylene glycol monohexyl ether "BTG (butyl triglycol)": Also known as triethylene glycol monobutyl ether -Other surfactants- "PD002W": Olfine PD002W manufactured by Nissin Chemical Industry Co., Ltd.

[0196] 3.2 Preparation Example 1 (Silicone Surfactant 2) A specific organohydrogenpolysiloxane was reacted with a polyether having a corresponding carbon-carbon double bond at the molecular end using platinum catalyst. Structural analysis of the resulting product using a liquid chromatography mass spectrometer (LC-MS) revealed that in the above general formulas (3) and (4), d = 3 to 5, e = 1 to 4, f = 1 to 4, g = 0, R 3 =CH3, R 4 =-CH2-, R 5 Silicone surfactant 2 of Preparation Example 1 satisfying =H was obtained.

[0197] 3.3 Molecular weight distribution measurement The molecules of silicone surfactant 1 and silicone surfactant 2 in Tables 1 to 3 above The molecular weight distribution was measured by gel permeation chromatography, and the maximum peak was obtained in the range of molecular weight of 300 or more. The measurement conditions were as follows: <Measurement conditions> Solvent: Tetrahydrofuran Column: TSKgel Super HZM-N x 2 · +TSKgel guardcolumn SuperHZ-L Column temperature: 40℃ ·Injection volume: 25μL Detector: Differential Refractive Index (RI) ·Flow rate: 0.35mL / min Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) A calibration curve using 13 samples with Mw = 1,000,000 to 500 was used.

[0198] 3.4 Recording Method A printer (modified Seiko Epson SC-S80650) was prepared, and each ink composition was loaded into one nozzle row of the inkjet head. The inkjet head used had a nozzle row with a nozzle density of 360 dpi and 360 nozzles. The printer also had a platen heater opposite the inkjet head for primary drying, and controlled the surface temperature of the recording medium to the values ​​listed in Tables 4 to 6 below. Furthermore, a secondary heater was provided downstream of the printer, and during secondary drying, the surface temperature of the recording medium was adjusted to 70°C. Here, the primary drying mechanism in this example was equipped with a platen heater and a blower fan, and the fan's air speed was the value listed in the table. The air speed was measured near the surface of the recording medium directly below the inkjet head. The air temperature was measured in advance to avoid being affected by the platen heater, and was measured near the surface of the recording medium.

[0199] Using the printer configured in this way, a solid pattern was printed in four passes at a printing resolution of 720 x 720 dpi on "M1": PET50A (a transparent PET film manufactured by Lintec) or "M2": plain paper (P paper by Xerox) under the conditions shown in Tables 4 to 6 below. In this printing, the number of ink droplets per pass was adjusted to achieve a deposition amount of 7 mg / inch. 2 It was set to be.

[0200] In Tables 4 to 6 below, "silicone surfactant amount Bk<color" indicates whether the total amount of silicone surfactant in the black ink composition used in each example is less than the total amount of silicone surfactant in the chromatic ink compositions used in each example, and is marked "Y" if it is less, and "N" if it is not. Also, the "media surface temperature" in the tables refers to the temperature during the primary drying process.

[0201] [Table 4]

[0202] [Table 5]

[0203] [Table 6]

[0204] 3.5 Evaluation Method In each of the Examples, Comparative Examples, and Reference Examples, evaluation tests were carried out on image quality (border bleeding), image quality (OD value), image quality (unevenness), and abrasion resistance. The methods used are described below. All evaluations of image quality were carried out from the recording surface side. Except for image quality (boundary bleeding), evaluation tests were carried out using patterns recorded using each ink composition alone by the above recording method.

[0205] 3.5.1 Image Quality (Boundary Smear) The recorded matter on which a grid pattern with a width of 1 mm was printed using the above recording method was visually observed and judged according to the following evaluation criteria. Note that the evaluation test for image quality (boundary bleeding) allows evaluation of inter-ink color mixing. (Evaluation criteria) A: No visible boundary bleeding and no difference in the grid width of each color B: No visible boundary bleeding, but differences in grid width are visible for each color C: Boundary bleeding is visible D: Boundary bleeding is noticeable

[0206] 3.5.2 Image Quality (OD Value) The OD value of the solid image of the recorded matter obtained by the above recording method was measured using a colorimeter (i1Pro2, manufactured by X-rite) under the following measurement conditions, and the result was evaluated according to the following evaluation criteria. Note that the evaluation test for image quality (OD value) makes it possible to evaluate the wetting and spreading properties of the ink. (Measurement conditions) Measurement device: i1Pro2 (manufactured by X-rite) Measurement conditions: D50 light source, status T, standard observer 2° Background: Blank paper (Evaluation criteria) A:OD value is 1.2 or more B: OD value is 1.0 or more and less than 1.2 C: OD value is 0.8 or more and less than 1.0 D: OD value is 0.6 or more and less than 0.8

[0207] 3.5.3 Image Quality (Unevenness) The solid image of the recorded matter obtained by the above recording method was visually observed and judged according to the following evaluation criteria. Note that, although poor ink wetting and spreading properties tend to deteriorate image quality (unevenness), it should be noted that factors other than wetting and spreading properties, such as ink drying properties, also affect image quality (unevenness). (Evaluation criteria) A: There does not appear to be any unevenness in the color shading within the pattern. B: Minor variations in shading are slightly visible C: Fine variations in shading are clearly visible D: Significant unevenness in shade is visible

[0208] 3.5.4 Scratch resistance The solid areas of the patterns obtained by the above recording method were subjected to a rub fastness test (JIS P 8136) using a Gakushin-type rub fastness tester AB-301 (manufactured by Tester Sangyo Co., Ltd.) in which a No. 3 gold-stripe cloth was rubbed back and forth 50 times with a load of 500 g, and the results were evaluated according to the following criteria. (Evaluation criteria) A: No peeling of the image is observed B: Less than 10% peeling C: Peeling of 10% to less than 40% D: 40% or more peeling or recording medium is torn

[0209] 3.6 Evaluation Results The evaluation results are shown in Tables 4 to 6 above.

[0210] From Tables 4 to 6 above, it is possible to determine whether an ink set comprising a black ink composition containing a black coloring material and a chromatic color ink composition containing a coloring material is suitable for printing on a low-absorbency recording medium or a non-absorbency recording medium. The black ink composition and the chromatic color ink compositions are water-based inkjet inks, and the chromatic color ink compositions contain a silicone surfactant 1 that has a maximum peak in the molecular weight range of 300 or more in a range of 3,000 to 20,000 in a molecular weight distribution measured by gel permeation chromatography, and the black ink composition contains at least one of a glycol monoether solvent and a silicone surfactant 2 that has a maximum peak in the molecular weight range of 300 or more in a range of 300 to 1,500 in a molecular weight distribution measured by gel permeation chromatography. In each example, the black ink composition has excellent wetting and spreading properties, resulting in excellent image quality (OD value), and excellent reduction in color mixing between the black ink composition and the chromatic color ink compositions, resulting in excellent image quality (boundary bleeding).

[0211] Comparing Example 1 with Comparative Examples 1 to 3, when the black ink composition contained a glycol monoether solvent or specific silicone surfactant 2, the black ink composition had excellent wetting and spreading properties, and the image quality (OD value) and image quality (unevenness) were excellent.

[0212] Comparing Example 1 with Comparative Examples 4 to 7, it was found that when the chromatic ink composition contained specific silicone surfactant 1, color mixing between the black ink composition and the chromatic ink composition was significantly reduced, resulting in excellent image quality (border bleeding).

[0213] Comparing Example 1 with Comparative Example 8, when the black ink composition contains a glycol monoether solvent or specific silicone surfactant 2 and the chromatic color ink composition contains specific silicone surfactant 1, the black ink composition has excellent wetting and spreading properties, resulting in excellent image quality (OD value), and also excellent reduction in color mixing between the black ink composition and the chromatic color ink composition, resulting in excellent image quality (border bleeding), thereby achieving both.

[0214] From the results of Example 1 and Reference Examples 1 and 2, the problem of the present invention occurred when recording on a low-absorbency recording medium or a non-absorbency recording medium.

[0215] The results of Examples 1, 2, and 18 show that when the content of specific silicone surfactant 2 in the black ink composition is within a certain range, the image quality (border bleeding) and the image quality (OD value) of the black ink composition are excellent.

[0216] The results of Examples 1 and 3 show that when the black ink composition further contains specific silicone surfactant 1, both the wetting and spreading properties of the black ink composition and inter-ink color mixing can be more excellently achieved.

[0217] The results of Examples 1, 4, and 5 show that when the content of glycol monoether solvent in the black ink composition is within a certain range, the image quality (border bleeding) and the image quality (OD value) of the black ink composition are excellent.

[0218] The results of Examples 6 and 7 show that even when the black ink composition contains only a glycol monoether solvent among glycol monoether solvents or specific silicone surfactant 2, excellent image quality (border bleeding) and image quality (OD value) of the black ink composition can be achieved at the same time.

[0219] The results of Examples 1, 8, and 9 show that the black ink composition was able to achieve both excellent image quality (border bleeding) and excellent image quality (OD value) of the black ink composition using various glycol monoether solvents.

[0220] The results of Examples 1, 10 to 15, and 23 show that the black ink composition was able to achieve both excellent image quality (border bleeding) and excellent image quality (OD value) of the black ink composition using various organic solvents.

[0221] The results of Example 16 show that even when the black ink composition contains only specific silicone surfactant 2 out of glycol monoether solvent or specific silicone surfactant 2, excellent image quality (border bleeding) and image quality of the black ink composition (OD value) can be achieved at the same time.

[0222] The results of Examples 1 and 17 show that the black ink composition containing various specific silicone surfactants 2 was able to achieve both excellent image quality (border bleeding) and excellent image quality (OD value) of the black ink composition.

[0223] The results of Examples 1 and 19 show that when the content of the organic solvent in the black ink composition is within a certain range, the image quality (border bleeding), the abrasion resistance of the black ink composition, and the image (unevenness) can be improved.

[0224] The results of Examples 1, 21, and 29 show that chromatic ink compositions that do not contain specific silicone surfactant 2 tend to provide better image quality (border bleeding).

[0225] The results of Examples 1, 22, 27, and 28 show that when the content of specific silicone surfactant 1 in the chromatic color ink composition is within a certain range, the image quality (border bleeding) is excellent.

[0226] The results of Examples 1 and 23 to 25 show that when the chromatic color ink composition contains a glycol monoether solvent, the wetting and spreading properties of the chromatic color ink composition tend to be improved and the image quality (border bleeding) also tends to be excellent.

[0227] The results of Examples 1 and 26 show that the chromatic ink compositions containing various specific silicone surfactants 1 provided excellent image quality (border bleeding).

[0228] The results of Examples 1, 6, and 30 to 35 show that, under various recording conditions, both excellent image quality (border bleeding) and image quality of the black ink composition (OD value) were achieved.

[0229] The following can be derived from the above-described embodiment.

[0230] One aspect of the ink set is An ink set comprising a black ink composition containing a black coloring material and a chromatic color ink composition containing a coloring material, It is used for recording on low-absorbency recording media or non-absorbency recording media, the black ink composition and the chromatic color ink composition are water-based inkjet inks, the chromatic color ink composition contains a silicone surfactant 1 that, in a molecular weight distribution measured by gel permeation chromatography, has a maximum peak in the range of 3,000 to 20,000 in a molecular weight range of 300 or more; The black ink composition contains at least one of a glycol monoether solvent and a silicone surfactant 2 having a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography.

[0231] In one embodiment of the ink set, the black ink composition contains the glycol monoether solvent, The glycol monoether solvent may be a glycol monoether having an alkyl ether moiety with 5 or more or 2 or less carbon atoms.

[0232] In any one of the above ink sets, The content of the glycol monoether solvent is 2% by weight based on the total weight of the black ink composition. It may be % by mass or less.

[0233] In any one of the above ink sets, The total content of silicone surfactants in the chromatic ink compositions may be greater than the total content of silicone surfactants in the black ink composition.

[0234] In any one of the above ink sets, The silicone surfactant 1 may have a structure represented by the following general formula (1) or (3). [ka] (In general formula (1), R 1each independently represents an alkylene group having 1 to 6 carbon atoms or a single bond; X 1 each independently represents a polyether group represented by the following general formula (2), and a is an integer of 10 or more and 80 or less. [ka] (In general formula (2), R 2 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a (meth)acrylic group; EO represents an ethylene oxide group; PO represents a propylene oxide group; (EO) b and (PO) c The order of is unspecified, b is an integer greater than or equal to 0, and c is an integer greater than or equal to 0, provided that b+c is an integer greater than or equal to 1.) [ka] (In general formula (3), R 3 each independently represents an alkyl group having 1 to 6 carbon atoms; X 2 each independently represents a polyether group represented by the following general formula (4), where d and e are integers of 1 or more, and d+e is an integer of 2 or more and 50 or less. [ka] (In general formula (4), R 4 represents an alkylene group having 1 to 6 carbon atoms or a single bond, and R 5 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, EO represents an ethylene oxide group, PO represents a propylene oxide group, (EO) f and (PO) g The order of is unspecified, f is an integer greater than or equal to 0, and g is an integer greater than or equal to 0, provided that f+g is an integer greater than or equal to 1.)

[0235] In any one of the above ink sets, The black ink composition may contain the glycol monoether solvent and the silicone surfactant 2.

[0236] In any one of the above ink sets, In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, The content of the organic solvent having a normal boiling point of less than 200°C may be 50 parts by mass or more per 100 parts by mass of the total amount of the organic solvents.

[0237] In any one of the above ink sets, In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, The content of the organic solvent may be 5 to 30% by mass relative to the total mass of the ink composition.

[0238] In any one of the above ink sets, In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, The organic solvent having the highest normal boiling point among the organic solvents contained in the ink composition may have a normal boiling point of 250° C. or lower.

[0239] One aspect of the recording method is A recording method for recording on a low-absorbency recording medium or a non-absorbency recording medium using the ink set according to any one of the above aspects, a black ink applying step of applying the black ink composition to the recording medium by an inkjet method; and a chromatic ink applying step of applying the chromatic ink composition to the recording medium by an ink jet method.

[0240] In one aspect of the recording method, The method may further include a primary drying step of drying the black ink composition and the chromatic color ink compositions that have been applied to the recording medium.

[0241] In any one of the above recording methods, In the primary drying step, drying by blowing air is performed, The air flow may have a speed of 0.5 to 15 m / s.

[0242] In any one of the above recording methods, The surface temperature of the recording medium in the primary drying step may be 45° C. or less.

[0243] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments, such as configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0244] 1...inkjet recording device, 2...inkjet head, 3...IR heater, 4...platen heater, 5...heating heater, 6...cooling fan, 7...preheater, 8...ventilation fan, 9...carriage, 11...platen, 12...cartridge, 13...carriage moving mechanism, 14...conveying means, CONT...control unit, MS...main scanning direction, SS...sub-scanning direction, M...recording medium

Claims

1. An ink set comprising a black ink composition containing a black coloring material and a chromatic color ink composition containing a coloring material, It is used for recording on low-absorbency recording media or non-absorbency recording media, the black ink composition and the chromatic color ink composition are water-based inkjet inks, the chromatic color ink composition contains a silicone surfactant 1 having a maximum peak in the range of 3,000 to 20,000 in the molecular weight range of 300 or more in a molecular weight distribution measured by gel permeation chromatography; The black ink composition contains a glycol monoether solvent.

2. An ink set comprising a black ink composition containing a black colorant and a chromatic ink composition containing a colorant, It is used for recording on low-absorbency recording media or non-absorbency recording media, the black ink composition and the chromatic color ink composition are water-based inkjet inks, the chromatic color ink composition contains a silicone surfactant 1 having a maximum peak in the range of 3,000 to 20,000 in the molecular weight range of 300 or more in a molecular weight distribution measured by gel permeation chromatography; The black ink composition contains a silicone surfactant 2 that has a maximum peak in the molecular weight range of 300 or more in the range of 300 to 1,500 in the molecular weight distribution measured by gel permeation chromatography.

3. the black ink composition contains a glycol monoether solvent, 3. The ink set according to claim 1, wherein the glycol monoether solvent is a glycol monoether having an alkyl ether moiety with 5 or more or 2 or less carbon atoms.

4. 4. The ink set according to claim 1, wherein the content of the glycol monoether solvent is 2% by mass or less relative to the total mass of the black ink composition.

5. 5. The ink set according to claim 1, wherein the total content of the silicone surfactants in the chromatic ink compositions is greater than the total content of the silicone surfactants in the black ink composition.

6. 6. The ink set according to claim 1, wherein the silicone surfactant 1 has a structure represented by the following general formula (1) or (3): 【Chemical 1】 (In general formula (1), R １ each independently represents an alkylene group having 1 to 6 carbon atoms or a single bond; X １ each independently represents a polyether group represented by the following general formula (2), and a is an integer of 10 or more and 80 or less. 【Chemistry 2】 (In general formula (2), R ２ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a (meth)acrylic group; EO represents an ethylene oxide group; PO represents a propylene oxide group; (EO) ｂ and (PO) ｃ are in no particular order, b is an integer of 0 or more, c is an integer of 0 or more, and b+c is an integer of 1 or more.) 【Chemistry 3】 (In general formula (3), R ３ each independently represents an alkyl group having 1 to 6 carbon atoms; X ２ each independently represents a polyether group represented by the following general formula (4), where d and e are integers of 1 or more, and d+e is an integer of 2 or more and 50 or less. 【Chemistry 4】 (In general formula (4), R ４ represents an alkylene group having 1 to 6 carbon atoms or a single bond, and R ５ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, EO represents an ethylene oxide group, PO represents a propylene oxide group, (EO) ｆ and (PO) ｇ are in no particular order, f is an integer of 0 or more, and g is an integer of 0 or more, provided that f+g is an integer of 1 or more.

7. 7. The ink set according to claim 1, wherein the black ink composition contains a glycol monoether solvent and a silicone surfactant 2 that has, in a molecular weight distribution measured by gel permeation chromatography, a maximum peak in a molecular weight range of 300 or more in a range of 300 to 1,500.

8. In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, 8. The ink set according to claim 1, wherein the content of the organic solvent having a normal boiling point of less than 200°C is 50 parts by mass or more per 100 parts by mass of the total of the organic solvents.

9. In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, 8. The ink set according to claim 1, wherein the content of the organic solvent is 5 to 30% by mass relative to the total mass of the ink composition.

10. In each of the black ink composition and the chromatic color ink composition, Contains an organic solvent, 8. The ink set according to claim 1, wherein the organic solvent having the highest normal boiling point among the organic solvents contained in the ink composition has a normal boiling point of 250°C or less.

11. A recording method for recording on a low-absorbency recording medium or a non-absorbency recording medium using the ink set according to any one of claims 1 to 10, a black ink applying step of applying the black ink composition to the recording medium by an inkjet method; a chromatic color ink applying step of applying the chromatic color ink composition to the recording medium by an inkjet method.

12. The recording method according to claim 11 , further comprising a primary drying step of drying the black ink composition and the chromatic color ink compositions adhered to the recording medium.

13. In the primary drying step, drying by blowing air is performed, 13. The recording method according to claim 12, wherein the air blowing has a wind speed of 0.5 to 15 m / s.

14. 14. The recording method according to claim 12, wherein the surface temperature of the recording medium in the primary drying step is 45° C. or less.

Images