Recording method and recording device

Abstract

To provide a recording method in which the image quality of an image formed by a white ink composition and the image quality of an image formed by a non-white ink composition are good.SOLUTION: There is provided a recording method which comprises: a white ink adhering step of adhering a white ink composition containing a white coloring material to a recording medium; a non-white ink adhering step of adhering a non-white ink composition containing a non-white coloring material overlapping the adhered white ink composition; a first treatment liquid adhering step of adhering a treatment liquid containing a coagulant to the recording medium accompanying the white ink adhering step; and a second treatment liquid adhering step of adhering a treatment liquid containing a coagulant to the recording medium accompanying the non-white ink adhering step, wherein the white ink composition has a viscosity increase of 5 times or more when mixed at a mass ratio of a white ink composition: a calcium formate 7 mass% aqueous solution=10:1 and the amount adhered of the treatment liquid in the second treatment liquid adhering step is smaller than the amount adhered of the treatment liquid in the first treatment liquid adhering step.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a recording method and a recording apparatus.

Background Art

[0002] Recording methods using a processing liquid to record high-definition images have been studied in various fields. Also, attempts have been made to improve the visibility of images by printing a white image and a non-white image over each other.

[0003] For example, Patent Document 1 discloses an ink set that includes a reaction liquid containing a flocculant, a first ink containing a white coloring material, and a second ink containing a non-white coloring material, and the reaction liquid, the first ink, and the second ink are applied to a recording medium in this order and used by being overlaid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In order to obtain excellent image quality of the white ink composition layer, when increasing the reactivity of the white ink composition with the processing liquid, the flocculant in the reaction liquid is consumed due to aggregation of the components of the white ink composition, so that the components of the non-white ink composition cannot sufficiently react with the flocculant, and the image quality of the non-white ink composition may deteriorate. Thus, there is a need for a recording method in which the image quality of the image formed by the white ink composition and the image quality of the image formed by the non-white ink composition are good.

Means for Solving the Problems

[0006] One aspect of the recording method according to the present invention is A white ink application step involves applying a white ink composition containing a white colorant to a recording medium, A non-white ink application step involves applying a non-white ink composition containing a non-white colorant to the aforementioned adhering white ink composition, A first processing liquid application step is performed in conjunction with the white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. A second processing liquid application step is performed in conjunction with the non-white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. Equipped with, The aforementioned white ink composition exhibits a viscosity increase of 5 times or more when mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:1. The amount of processing liquid applied in the second processing liquid application step is smaller than the amount of processing liquid applied in the first processing liquid application step.

[0007] One aspect of the recording device according to the present invention is: The recording method described above comprises an adhesion mechanism for performing the white ink adhesion step, an adhesion mechanism for performing the non-white ink adhesion step, an adhesion mechanism for performing the first processing liquid adhesion step, and an adhesion mechanism for performing the second processing liquid adhesion step. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram of an example of an inkjet recording apparatus that can be used in the recording method of the embodiment. [Figure 2] A schematic diagram of the carriage area of ​​an example of an inkjet recording apparatus that can be used in the recording method of the embodiment. [Figure 3] A block diagram of an example of an inkjet recording apparatus used in the recording method of the embodiment. [Figure 4] A schematic diagram of an example of an inkjet head of an inkjet recording apparatus that can be used in the recording method of the embodiment. [Figure 5] A schematic diagram of another example of an inkjet recording apparatus that can be used in the recording method of the embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention are described below. The embodiments described below illustrate examples of the present invention. The present invention is not limited in any way to the embodiments described below and includes various modifications that are implemented without changing the gist of the present invention. Not all of the configurations described below are necessarily essential to the present invention.

[0010] 1. Recording Method The recording method according to this embodiment comprises a white ink attachment step of attaching a white ink composition containing a white colorant to a recording medium; a non-white ink attachment step of attaching a non-white ink composition containing a non-white colorant on top of the attached white ink composition; a first processing liquid attachment step, accompanying the white ink attachment step, of attaching a processing liquid containing a flocculant to the recording medium; and a second processing liquid attachment step, accompanying the non-white ink attachment step, of attaching a processing liquid containing a flocculant to the recording medium. The white ink composition has a viscosity increase of 5 times or more when mixed in a mass ratio of white ink composition: 7% by mass aqueous solution of calcium formate = 10:1, and the amount of processing liquid attached in the second processing liquid attachment step is smaller than the amount of processing liquid attached in the first processing liquid attachment step.

[0011] 1.1. White ink application process The white ink application process involves applying a white ink composition to a recording medium. The white ink composition is described below. The method of application to the recording medium will be described later.

[0012] The white ink composition may be any ink other than being a water-based ink containing a white colorant. Examples of water-based inks include those containing a solvent component that can evaporate, in addition to water. Furthermore, the water-based ink may also be a water-based resin ink containing a resin. With such an ink, recording is performed when the solvent component dries and evaporates from the ink adhering to the recording medium, leaving components such as the colorant on the recording medium.

[0013] 1.1.1.White color material The white ink composition contains a white colorant. Examples of white colorants include metal compounds such as metal oxides, barium sulfate, and calcium carbonate. Examples of metal oxides include titanium dioxide, zinc oxide, silica, alumina, and magnesium oxide. In addition, particles having a hollow structure may be used as the white colorant, and known particles with a hollow structure can be used.

[0014] As a white coloring agent, titanium dioxide is preferred from the viewpoint of good whiteness and abrasion resistance among the examples given above. The white coloring agent may be used alone or in combination of two or more types.

[0015] The volume-based average particle diameter (D50) of the white colorant (also called "volume-average particle diameter") is set to be larger than the volume-average particle diameter of the inorganic fine particles described later. The volume-average particle diameter of the white colorant is preferably 30.0 nm to 600.0 nm, more preferably 100.0 nm to 500.0 nm, and even more preferably 150.0 nm to 400.0 nm. If the volume-average particle diameter of the white colorant is within the above range, the particles are less likely to settle. Furthermore, dispersion stability can be improved, and nozzle clogging and other issues can be reduced when applied to an inkjet recording device. In addition, if the volume average particle size of the white colorant is within the aforementioned range, it can significantly contribute to improving the visibility of the image.

[0016] The volume-average particle size of the white colorant can be measured using a particle size distribution analyzer. Examples of such analyzers include particle size analyzers that use dynamic light scattering as their measurement principle (e.g., the "NanoTrac series" manufactured by MicroTracBell). The volume-average particle size is defined as the D50 value.

[0017] In this specification, the term "white" when referring to a white ink composition, white coloring material, etc. does not refer only to pure white, but includes colors colored with chromatic or achromatic colors and glossy colors as long as they can be visually recognized as white. Further, it includes those named and sold in a way that suggests that the ink or pigment is a white ink or white pigment.

[0018] More quantitatively, "white" means that the recorded matter, for example in CIELAB, not only has a color with L * equal to 100, but also includes colors with L * being 60 or more and 100 or less, and a * and b * each being ±10 or less.

[0019] More specifically, for example, when a white ink composition is recorded in an amount sufficient to fully cover the surface of a recording medium made of a transparent film with the ink, the lightness (L * ) and chromaticity (a * , b * ) of the recorded part of the recorded matter are preferably within the above range when measured with a spectrophotometer conforming to CIELAB. The recorded matter recorded in an amount sufficient to be fully covered has, for example, an adhesion amount of 15 mg / inch 2 . More preferably, 80 ≦ L * ≦ 100, -4.5 ≦ a * ≦ 2, -10 ≦ b * ≦ 2.5. Examples of the recording medium made of a transparent film include LAG Jet E-1000ZC (manufactured by Lintec Corporation). Examples of the spectrophotometer conforming to CIELAB include Spectrolino (trade name, manufactured by GretagMacbeth), and the measurement conditions are set as D50 light source, 2° observation field, DIN NB density, Abs white reference, No filter, Reflectance measurement mode, and measurement is performed.

[0020] Typical examples of white colorants include titanium dioxide, such as Typake CR-50-2, CR-57, CR-58-2, CR-60-2, CR-60-3, CR-Super-70, CR-90-2, CR-95, CR953, PC-3, PF-690, PF-691, PF-699, PF-711, PF-728, PF-736, PF-737, PF-739, PF-740, PF-742, R-980, and UT-771 (all manufactured by Ishihara Sangyo Co., Ltd.).

[0021] The content of white colorant (solids) in the white ink composition is preferably 0.5% to 20.0% by mass, more preferably 1.0% to 20.0% by mass, even more preferably 3.0% to 15.0% by mass, and even more preferably 7.0% to 12.0% by mass, based on the total mass of the white ink composition. If the content of white colorant is within the above range, an image with sufficient visibility can be obtained.

[0022] In the recording method of this embodiment, the white colorant has the function of concealing the background of the image and improving the visibility of the resulting image. The content of the white colorant in the white ink composition can be reduced when used for the purpose of improving the visibility of the image compared to when used for the purpose of concealing the background. Therefore, when the white ink composition is used for the purpose of improving the visibility of the image, sufficient visibility of the image can be obtained, and the dispersion stability of the white colorant can be easily improved, making it less likely to settle. From this viewpoint, the upper limit of the content of the white colorant in the white ink composition is preferably within the above range, and preferably 10.0% by mass or less.

[0023] The white pigment is preferably stably dispersed in a dispersion medium, and for this purpose, a dispersant may be used for dispersion. Examples of dispersants include resin dispersants, and they are selected from those that can ensure good dispersion stability of the white pigment in the white ink composition containing the white pigment. Alternatively, the white pigment may be used as a self-dispersing pigment by modifying the surface of the pigment particles by oxidizing or sulfonating the pigment surface with, for example, ozone, hypochlorous acid, or fuming sulfuric acid.

[0024] Examples of resin dispersants (dispersant resins) include (meth)acrylic resins and their salts such as poly(meth)acrylic acid, (meth)acrylic acid-acrylonitrile copolymer, (meth)acrylic acid-(meth)acrylic acid ester copolymer, vinyl acetate-(meth)acrylic acid ester copolymer, vinyl acetate-(meth)acrylic acid copolymer, vinylnaphthalene-(meth)acrylic acid copolymer; styrene-(meth)acrylic acid copolymer, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, styrene-α-methylstyrene-(meth)acrylic acid copolymer, styrene-α-methylstyrene-(meth)acrylic acid copolymer Examples of water-soluble resins include: styrene-based resins and their salts, such as acrylic acid-(meth)acrylic acid ester copolymers, styrene-maleic acid copolymers, and styrene-maleic anhydride copolymers; urethane-based resins and their salts, which are polymer compounds (resins) containing urethane bonds formed by the reaction of isocyanate groups and hydroxyl groups, and which may be linear and / or branched, with or without a crosslinked structure; polyvinyl alcohols; vinylnaphthalene-maleic acid copolymers and their salts; vinyl acetate-maleic acid ester copolymers and their salts; and vinyl acetate-crotonic acid copolymers and their salts. Among these, copolymers of monomers having hydrophobic functional groups and monomers having hydrophilic functional groups, and polymers consisting of monomers having both hydrophobic and hydrophilic functional groups are preferred. The copolymer can be used in any form, such as a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer.

[0025] Examples of commercially available styrene resin dispersants include X-200, X-1, X-205, X-220, X-228 (manufactured by Seikoh PMC), Nopcospers® 6100, 6110 (manufactured by Sunnopco Corporation), Joncryl 67, 586, 611, 678, 680, 682, 819 (manufactured by BASF), DISPERBYK-190 (manufactured by Bic Chemie Japan Co., Ltd.), N-EA137, N-EA157, N-EA167, N-EA177, N-EA197D, N-EA207D, and E-EN10 (manufactured by Daiichi Kogyo Seiyaku).

[0026] Furthermore, commercially available acrylic resin dispersants include BYK-187, BYK-190, BYK-191, BYK-194N, BYK-199 (manufactured by Big Chemie Co., Ltd.), Aron A-210, A6114, AS-1100, AS-1800, A-30SL, A-7250, and CL-2 (manufactured by Toagosei Co., Ltd.).

[0027] Furthermore, commercially available urethane resin dispersants include BYK-182, BYK-183, BYK-184, BYK-185 (manufactured by Bic Chemi Co., Ltd.), TEGO Disperse710 (manufactured by Evonic Tego Chemi), and Borchi® Gen1350 (manufactured by OMG Borschers).

[0028] The dispersant may be used alone or in combination of two or more types. The total content of the dispersant is preferably 0.1 parts by mass or more and 30 parts by mass or less per 50 parts by mass of the white colorant, more preferably 0.5 parts by mass or more and 25 parts by mass or less, even more preferably 1 part by mass or more and 20 parts by mass or less, and even more preferably 1.5 parts by mass or more and 15 parts by mass or less. By having a dispersant content of 0.1 parts by mass or more per 50 parts by mass of the white colorant, the dispersion stability of the white colorant can be further enhanced. If the amount is below parts by mass, the viscosity of the resulting dispersion can be kept low.

[0029] Among the dispersants exemplified above, it is even more preferable that at least one is selected from anionic dispersant resins. In this case, it is even more preferable that the weight-average molecular weight of the dispersant be 500 or more. Furthermore, it is preferable that it be between 5000 and 100000, and more preferably between 10000 and 50000.

[0030] By using such a resin dispersant as a dispersant, the dispersion and aggregation of the white pigment are improved, resulting in better dispersion stability and even better image quality. Furthermore, it is preferable that the viscosity of the white ink composition, as described later, can be increased by five times or more.

[0031] Anionic dispersant resins are resins that exhibit anionic properties because they possess anionic functional groups. Examples of anionic functional groups include carboxyl groups, sulfo groups, and phosphate groups. Among these groups, carboxyl groups are more preferred.

[0032] The dispersant resin preferably has an acid value, preferably 5 mg KOH / g or more, more preferably 10 to 200 mg KOH / g, and even more preferably 15 to 150 mg KOH / g. Further preferably 20 to 100 mg KOH / g, and even more preferably 25 to 70 mg KOH / g. In this case, it is preferable as it is easier to increase the viscosity of the white ink composition, as described later, by 5 times or more.

[0033] The acid value can be measured by neutralization potentiometric titration in accordance with JIS K0070. For example, the "AT610" manufactured by Kyoto Electronics Manufacturing Co., Ltd. can be used as the titrator.

[0034] 1.1.2. Other ingredients In addition to the white colorant, the white ink composition may also contain components such as water, resin particles, organic solvents, surfactants, waxes, additives, resin dispersants, preservatives / fungal agents, rust inhibitors, chelating agents, viscosity modifiers, antioxidants, and fungicides. These will be explained in detail below.

[0035] (water) The white ink composition used in the recording method according to this embodiment may contain water. Preferably, the white ink composition is a water-based white ink composition. A water-based composition is one that contains water as one of its main solvent components. This allows for recording with reduced environmental impact and less odor.

[0036] Water may be included as the main solvent component of the white ink composition and is a component that evaporates and dissipates upon drying. Preferably, the water is pure water or ultrapure water from which ionic impurities have been removed as much as possible, such as ion-exchanged water, ultrafiltered water, reverse osmosis water, or distilled water. Furthermore, using water sterilized by ultraviolet irradiation or hydrogen peroxide addition is preferable because it can suppress the growth of mold and bacteria when the ink is stored for a long period of time. The water content is preferably 45% by mass or more, more preferably 50% by mass or more and 98% by mass or less, and even more preferably 55% by mass or more and 95% by mass or less, relative to the total amount of the white ink composition.

[0037] (Resin particles) The white ink composition may contain resin particles. That is, the white ink composition may be a white aqueous resin ink. The resin particles can further improve the adhesion of the image formed by the white ink composition attached to the recording medium. Examples of resin particles include 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, Examples include resin particles made of ethylene vinyl acetate resin, etc. Among these, urethane resins, acrylic resins, polyolefin resins, and polyester resins are preferred. These resin particles are often handled in emulsion form, but they may also be in powder form. Furthermore, the resin particles can be used individually or in combination of two or more types.

[0038] Urethane resins are a general term for resins that have urethane bonds. In addition to urethane bonds, urethane resins may also include polyether-type urethane resins containing ether bonds in the main chain, polyester-type urethane resins containing ester bonds in the main chain, and polycarbonate-type urethane resins containing carbonate bonds in the main chain. Furthermore, commercially available urethane resins may be used, such as Superflex 460, 460s, 840, E-4000 (product names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Rezamin D-1060, D-2020, D-4080, D-4200, D-6300, D-6455 (product names, manufactured by Dainichi Seika Kogyo Co., Ltd.), Takelac WS-6021, W-512-A-6 (product names, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Sankyuar 2710 (product name, manufactured by LUBRIZOL), and Permarin UA-150 (product name, manufactured by Sanyo Chemical Industries, Ltd.).

[0039] Acrylic resins are a general term for polymers obtained by polymerizing at least one acrylic monomer, such as (meth)acrylic acid or (meth)acrylic acid ester. Examples include resins obtained from acrylic monomers and copolymers of acrylic monomers with other monomers. For example, acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers, are examples. Examples of vinyl monomers include styrene.

[0040] Acrylic monomers such as acrylamide and acrylonitrile can also be used. For resin emulsions made from acrylic resins, commercially available products may be used, for example, selected from FK-854 (trade name, manufactured by Chuo Rika Kogyo Co., Ltd.), Movinyl 952B, 718A (trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Nipol LX852, LX874 (trade name, manufactured by Nippon Zeon Co., Ltd.).

[0041] In this specification, the acrylic resin may also refer to the styrene-acrylic resin described later. Furthermore, in this specification, the term (meth)acrylic means at least one of acrylic and methacrylic.

[0042] Styrene-acrylic resins are copolymers obtained from styrene monomers and (meth)acrylic monomers, and examples 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. For the styrene-acrylic resin, commercially available products may be used, such as Joncryl 62J, 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (product names, manufactured by BASF), Movinyl 966A, 975N (product names, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Vinibran 2586 (manufactured by Nisshin Chemical Industry Co., Ltd.), etc.

[0043] Polyolefin resins have olefins such as ethylene, propylene, and butylene as their structural framework, and known types can be appropriately selected and used. Commercially available olefin resins can be used, for example, Arrowbase CB-1200, CD-1200 (trade names, manufactured by Unitika Ltd.).

[0044] Furthermore, the resin particles may be supplied in the form of an emulsion. Examples of commercially available resin emulsions include Microgel E-1002, E-5002 (product names of Nippon Paint Co., Ltd., styrene-acrylic resin emulsion), Boncoat 4001 (product name of DIC Corporation, acrylic resin emulsion), Boncoat 5454 (product name of DIC Corporation, styrene-acrylic resin emulsion), Polysol AM-710, AM-920, AM-2300, AP-4735, AT-860, PSASE-4210E (acrylic resin emulsion), and Poly Polysol AP-7020 (styrene-acrylic resin emulsion), Polysol SH-502 (vinyl acetate resin emulsion), Polysol AD-13, AD-2, AD-10, AD-96, AD-17, AD-70 (ethylene-vinyl acetate resin emulsion), Polysol PSASE-6010 (ethylene-vinyl acetate resin emulsion) (product name manufactured by Showa Denko), Polysol SAE1014 (product name, styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Saibinol SK-200 (product name, acrylic resin emulsion, manufactured by Saiden Chemical Co., Ltd.) AE-120A (JSR product name, acrylic resin emulsion), AE373D (E-Tech product name, carboxy-modified styrene-acrylic resin emulsion), Seikadine 1900W (Dainichi Seika Kogyo product name, ethylene-vinyl acetate resin emulsion), Vinibran 2682 (acrylic resin emulsion), Vinibran 2886 (vinyl acetate-acrylic resin emulsion), Vinibran 5202 (acrylic acetate resin emulsion) (Nisshin Chemical Industry product name), Elitel KA-5071S, KT-8803, KT-9204, KT-870 1. KT-8904, KT-0507 (Unitika Corporation product names, polyester resin emulsion), Hi-Tec SN-2002 (Toho Chemical Co., Ltd. product name, polyester resin emulsion), Takelac W-6020, W-635, W-6061, W-605, W-635, W-6021 (Mitsui Chemicals Polyurethane Co., Ltd. product names, urethane resin emulsion), Superflex 870, 800, 150, 420, 460, 470, 610, 700 (Daiichi Kogyo Seiyaku Co., Ltd. product names, urethane resin emulsion), Permarin UA-150 (Sanyo Chemical Industries, Ltd.Urethane resin emulsion), SunCure 2710 (manufactured by Lubrizol Japan, urethane resin emulsion), NeoRez R-9660, R-9637, R-940 (manufactured by Kusumoto Kasei Co., Ltd., urethane resin emulsion), Adekabon Titer HUX-380, 290K (manufactured by ADEKA Corporation, urethane resin emulsion), Movinyl 966A, Movinyl 7320 (manufactured by Nippon Synthetic Chemical Co., Ltd.), Joncryl 7100, 390, 711, 511, 7001, 632, 741, 450, 840, 74J, HRC-1645J, 734, 852, 7600, 775, 537J, 1535, PDX-7 You may also select and use from among 630A, 352J, 352D, PDX-7145, 538J, 7640, 7641, 631, 790, 780, 7610 (all manufactured by BASF), NK Binder R-5HN (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.), Hydran WLS-210 (non-crosslinked polyurethane: manufactured by DIC Corporation), Joncryl 7610 (manufactured by BASF), etc.

[0045] The glass transition temperature (Tg) of the resin particles is preferably between -50°C and 200°C, more preferably between 0°C and 150°C, and even more preferably between 50°C and 100°C. A temperature between 50°C and 80°C is particularly preferred. When the glass transition temperature (Tg) of the resin particles is within the above range, the durability and resistance to clogging tend to be superior. The glass transition temperature is measured, for example, using a differential scanning calorimeter "DSC7000" manufactured by Hitachi High-Tech Science Corporation, in accordance with JIS K7121 (Method for measuring the transition temperature of plastics).

[0046] The volume-average particle diameter of the resin particles is preferably 10 nm to 300 nm, more preferably 30 nm to 300 nm, even more preferably 30 nm to 250 nm, and particularly preferably 40 nm to 220 nm. The volume-average particle diameter can be measured by the method described above.

[0047] The resin of the resin particles preferably has an acid value of 50 mgKOH / g or less, more preferably 30 mgKOH / g or less, even more preferably 20 mgKOH / g or less, and particularly preferably 10 mgKOH / g or less. The lower limit of the acid value is 0 mgKOH / g or more, preferably 5 mgKOH / g or more, and more preferably 10 mgKOH / g or more. In this case, superior image quality is desirable. The acid value can be measured by the method described above.

[0048] When resin particles are included in the white ink composition, the content is 0.1% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by mass or less, and more preferably 2% by mass or more and 10% by mass or less, as solid content, relative to the total mass of the white ink composition.

[0049] (Organic solvents) The white ink composition used in the recording method according to this embodiment may contain an organic solvent. The organic solvent is preferably water-soluble. One function of the organic solvent is to improve the wettability of the white ink composition to the recording medium and to enhance the moisture retention of the white ink composition. The organic solvent can also function as a penetrating agent.

[0050] Examples of organic solvents include esters, alkylene glycol ethers, cyclic esters, nitrogen-containing solvents, and polyhydric alcohols. Examples of nitrogen-containing solvents include cyclic amides and acyclic amides. Examples of acyclic amides include alkoxyalkylamides.

[0051] Examples of esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether acetate, as well as glycol diesters such as ethylene glycol diacetate, diethylene glycol diacetate, and propylene glycol diacetate.

[0052] The alkylene glycol ethers can be any monoether or diether of alkylene glycol, with alkyl ethers being preferred. Specific examples include alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and diethylene glycol monomethyl ether, and alkylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether.

[0053] Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, and β-butyrolactone, as well as compounds in which the hydrogen atoms of the methylene group adjacent to the carbonyl group are substituted with alkyl groups having 1 to 4 carbon atoms.

[0054] Examples of alkoxyalkylamides 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-diethylpropionamide, 3-ethoxy-N,N-methylethylpropionamide, 3-n-butoxy-N,N-dimethylpropionamide, 3-n-butoxy-N,N-diethylpropionamide, and 3-n-butoxy-N,N-methylethylpropionamide.

[0055] Examples of cyclic amides include lactams, such as 2-pyrrolidone and 1-methyl Examples include pyrrolidones such as -2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone. These are preferred in terms of their solubility as a flocculant and their ability to promote the film formation of resin particles, as described later, with 2-pyrrolidone being particularly preferred.

[0056] Furthermore, it is also preferable to use compounds represented by the following general formula (1) as alkoxyalkylamides.

[0057] R 1 -O-CH2CH2-(C=O)-NR 2 R 3 ...(1)

[0058] In the above equation (1), R 1 R represents an alkyl group having 1 to 4 carbon atoms. 2 and R 3 Each independently represents either a methyl group or an ethyl group. The "alkyl group having 1 to 4 carbon atoms" can be a linear or branched alkyl group, for example, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, or a tert-butyl group. The compound represented by formula (1) above may be used alone or as a mixture of two or more.

[0059] One function of nitrogen-containing solvents is to enhance the surface drying and fixing properties of white ink compositions attached to low-absorption recording media. In particular, the compound represented by formula (1) has excellent properties for moderately softening and dissolving vinyl chloride resins. Therefore, the compound represented by formula (1) can soften and dissolve the recording surface containing vinyl chloride resin, allowing the white ink composition to penetrate into the interior of the low-absorption recording media. As the white ink composition penetrates the low-absorption recording media in this way, the white ink composition becomes firmly fixed, and the surface of the white ink composition dries easily. Consequently, the resulting image tends to have excellent surface drying properties and fixing properties.

[0060] The nitrogen-containing solvent content is not particularly limited, but is preferably between 5% and 50% by mass, and between 10% and 30% by mass, relative to the total mass of the white ink composition. Having the content within this range may further improve image fixation and surface drying properties (especially surface drying properties when recorded in a high-temperature, high-humidity environment).

[0061] Examples of polyhydric alcohols include 1,2-alkanediols (e.g., ethylene glycol, propylene glycol (also known as propane-1,2-diol), 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, and other alkanediols), and polyhydric alcohols other than 1,2-alkanediols (polyols) (e.g., diethylene glycol, dipropylene glycol, 1,3-propanediol, 1,3-butanediol (also known as 1,3-butylene)). Examples include glycols, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol, trimethylolpropane, glycerin, etc.

[0062] Polyhydric alcohols include alkanediols and polyols. Alkanediols are diols of alkanes having 5 or more carbon atoms. The number of carbon atoms in the alkane is preferably 5 to 15, more preferably 6 to 10, and even more preferably 6 to 8. Preferably, they are 1,2-alkanediols.

[0063] Polyols are polyols of alkanes with 4 or fewer carbon atoms, or polyols of alkanes with 4 or fewer carbon atoms. It is an intermolecular condensate of hydroxyl groups of riols. The number of carbon atoms in the alkane is preferably 2 to 3. The number of hydroxyl groups in the polyol molecule is 2 or more, preferably 5 or less, and more preferably 3 or less. When the polyol is the above intermolecular condensate, the number of intermolecular condensations is 2 or more, preferably 4 or less, and more preferably 3 or less. The polyhydric alcohols can be used individually or as a mixture of two or more.

[0064] Alkanediols and polyols can primarily function as penetrating solvents and / or moisturizing solvents. However, alkanediols tend to have stronger penetrating properties, while polyols tend to have stronger moisturizing properties.

[0065] When the white ink composition contains an organic solvent, one type of organic solvent may be used alone, or two or more types may be used in combination. Furthermore, the total content of the organic solvent relative to the total mass of the white ink composition is, for example, 5% by mass or more and 50% by mass or less, preferably 10% by mass or more and 45% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less. Having the organic solvent content within the above range provides an even better balance between wetting spreadability and drying properties, making it easier to form higher quality images.

[0066] Furthermore, it is more preferable that the white ink composition contains an organic solvent among the examples of organic solvents above, with a standard boiling point of 150.0°C to 280.0°C. This allows for faster drying and fixing of the formed image.

[0067] Furthermore, it is more preferable that the white ink composition does not contain more than 1.0% by mass of organic solvents of polyols having a standard boiling point above 280.0°C. The content of organic solvents of polyols having a standard boiling point above 280°C in the white ink composition is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and most particularly preferably 0.1% by mass or less, based on the total mass of the white ink composition. The lower limit of the content of organic solvents of polyols having a standard boiling point above 280°C may be 0% by mass.

[0068] This method allows for better drying of the formed image, enables faster recording, and improves adhesion to the recording medium. Furthermore, it is even more preferable that the white ink composition contains an organic solvent (not limited to polyols) with a standard boiling point exceeding 280.0°C within the above range. Examples of organic solvents with a standard boiling point exceeding 280°C include glycerin and polyethylene glycol monomethyl ether.

[0069] (Surfactants) The white ink composition may contain a surfactant. The surfactant has the function of adjusting the surface tension of the white ink composition, for example, adjusting the wettability with the recording medium. Among surfactants, acetylene glycol-based surfactants, silicone-based surfactants, and fluorine-based surfactants can be preferably used.

[0070] Acetylene glycol-based surfactants are not particularly limited, but examples include Surfinol 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, DF110D (all of the above are product names, Air-P (Manufactured by Products & Chemicals), Olphine 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, AE-3 (all product names, manufactured by Nisshin Chemical Industry Co., Ltd.), Acetyleneol E00, E00P, E40, E100 (all Examples include products manufactured by Kawaken Fine Chemicals Co., Ltd.

[0071] While not particularly limited, polysiloxane compounds are preferred as silicone-based surfactants. While not particularly limited, examples of polysiloxane compounds include polyether-modified organosiloxanes. Examples of commercially available polyether-modified organosiloxanes include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (all trade names, manufactured by BYK-Chemie Japan), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF- Examples include 615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (all product names, manufactured by Shin-Etsu Chemical Co., Ltd.), Silface SAG002, 005, 503A, 008 (all product names, manufactured by Nisshin Chemical Industry Co., Ltd.).

[0072] As fluorine-based surfactants, it is preferable to use fluorine-modified polymers. Specific examples include BYK-3440 (manufactured by Bic Chemie Japan), Surflon S-241, S-242, S-243 (all trade names, manufactured by AGC Seimi Chemical Co., Ltd.), and Futergent 215M (manufactured by Neos Co., Ltd.).

[0073] When a surfactant is included in the white ink composition, multiple types may be included. The amount of surfactant included in the white ink composition can be 0.1% by mass or more and 2% by mass or less, preferably 0.4% by mass or more and 1.5% by mass or less, and more preferably 0.5% by mass or more and 1.0% by mass or less, based on the total mass of the white ink composition.

[0074] (wax) The white ink composition may contain wax. The wax has the function of providing a smooth surface to the image created by the white ink composition, thereby reducing peeling of the image.

[0075] The components of the wax can be, for example, plant and animal waxes such as carnauba wax, candelilla wax, beeswax, rice wax, and lanolin; petroleum waxes such as paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, and petrolatum; mineral waxes such as montan wax and ozokerite; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, and stearic acid amide; and natural and synthetic wax emulsions and blended waxes such as α-olefin-maleic anhydride copolymers, which can be used individually or in combination of multiple types. Among these, polyolefin wax (especially polyethylene wax and polypropylene wax) and paraffin wax are preferred from the viewpoint of being superior in their ability to improve adhesion to flexible packaging films, as described later.

[0076] Commercially available waxes can be used as is, for example, Nopcoat PEM-17 (product name, manufactured by Sunnopco Co., Ltd.), Chemipearl W4005 (product name, manufactured by Mitsui Chemicals, Inc.), and AQUACER 515, 539, and 593 (all product names, manufactured by Big Chemie Japan Co., Ltd.).

[0077] Furthermore, when the recording method includes a heating process, it is preferable to use a wax with a melting point of 50°C to 200°C, more preferably 70°C to 180°C, and even more preferably 90°C to 150°C, in order to prevent the wax from melting too much and degrading its performance.

[0078] The wax may be supplied in the form of an emulsion or suspension. The wax content is 0.1% to 10% by mass, more preferably 0.5% to 5% by mass, and even more preferably 0.5% to 2% by mass, based on solid content relative to the total mass of the white ink composition. When the wax content is within the above range, the functions of the wax can be well exhibited. Furthermore, if either or both of the white ink composition and the non-white ink composition described later contain wax, the function of imparting smoothness to the image can be sufficiently obtained.

[0079] (Additives) The white ink composition may contain additives such as ureas, amines, and sugars. Examples of ureas include urea, ethylene urea, tetramethylurea, thiourea, 1,3-dimethyl-2-imidazolidinone, and betaines (trimethylglycine, triethylglycine, tripropylglycine, triisopropylglycine, N,N,N-trimethylalanine, N,N,N-triethylalanine, N,N,N-triisopropylalanine, N,N,N-trimethylmethylalanine, carnitine, acetylcarnitine, etc.).

[0080] Examples of amines include diethanolamine, triethanolamine, and triisopropanolamine. Ureas and amines may also be used as pH adjusters. Examples of sugars include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, and maltotriose.

[0081] (others) The white ink composition used in the recording method according to this embodiment may further contain, if necessary, components such as preservatives, antifungal agents, rust inhibitors, chelating agents, viscosity modifiers, antioxidants, and fungicides.

[0082] 1.1.3. Physical properties of the white ink composition When a white ink composition is applied to a recording medium by an inkjet method, the viscosity of the white ink composition is preferably 1.5 mPa·s to 15 mPa·s at 20°C, more preferably 1.5 mPa·s to 7 mPa·s, and even more preferably 1.5 mPa·s to 5.5 mPa·s. When a white ink composition is applied to a recording medium by an inkjet method, it is easy to efficiently form a predetermined image on the recording medium.

[0083] From the viewpoint of ensuring proper wetting and spreading properties on the recording medium, the surface tension of the white ink composition at 25°C is preferably 40 mN / m or less, more preferably 38 mN / m or less, more preferably 35 mN / m or less, and even more preferably 30 mN / m or less. Furthermore, a surface tension of 20 mN / m or more is desirable, and 25 mN / m or more is even more preferable.

[0084] Surface tension can be measured using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) by checking the surface tension when a platinum plate is wetted with the composition in an environment of 25°C.

[0085] 1.1.4. Thickness of the white ink composition The white ink composition exhibits a viscosity increase of 5 times or more when mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:1. This viscosity-increasing property ensures sufficient aggregation of the components of the white ink composition upon contact with the processing solution, and also improves the image quality of the image formed by the non-white ink composition and the image quality of the non-white ink composition used in conjunction with it. Excellent. It can particularly reduce the thinning of fine lines used in writing and other text.

[0086] Here, with regard to the increase in viscosity of ink when mixed with a 7% by mass aqueous solution of calcium formate (test solution), the "viscosity increase rate" is defined as follows: The viscosity increase rate is the ratio (multiplier) of the viscosity of the mixed solution to the viscosity of the ink before mixing, when the ink and the 7% by mass aqueous solution of calcium formate used in the recording method are mixed and stirred in a mass ratio of 10:1. Viscosity is measured at 20°C. Therefore, the viscosity increase rate is a multiplier of the viscosity after mixing, based on the viscosity before mixing. The viscosity increase rate is, for example, between 0.5 and 10.0 times. Note that depending on the composition of the ink, the viscosity increase rate may be less than 1.0 times, and the viscosity may decrease, but it is still referred to as the viscosity increase rate. Viscosity can be measured using a rheometer.

[0087] The viscosity of the white ink composition has a lower limit of 5 times or more, but is more preferably greater than 5 times, more preferably 5.5 times or more, even more preferably 6 times or more, and particularly preferably 7 times or more. Furthermore, 10 times or more is preferred.

[0088] On the other hand, while there is no upper limit to the viscosity of the white ink composition, it is preferably 20 times or less, more preferably 10 times or less, more preferably 9 times or less, even more preferably 8.5 times or less, and even more preferably 8 times or less. When the viscosity of the white ink composition is within the above range, image quality, crack resistance, abrasion resistance, and discharge stability are better and preferable. Furthermore, the image quality of the non-white ink composition used together is also excellent, and the thinning of fine lines used in letters and the like can be reduced. In addition, since the image quality is excellent even when a large amount of ink is applied, the amount of ink applied can be increased, and the background opacity of white images is excellent.

[0089] The viscosity of the white ink composition can be adjusted primarily by adjusting the type and content of the white pigment (including the resin dispersant) and resin particles. In particular, adjusting the type and content of the white pigment (including the resin dispersant) is easier and therefore preferable.

[0090] 1.1.5. Method for applying a white ink composition to a recording medium The white ink application process can be carried out in any manner as long as the white ink composition is applied while scanning the recording medium with an inkjet head. For example, it is preferable to use an inkjet head and eject the white ink composition from the inkjet head. In this way, small-volume, multi-type printing can be efficiently performed with a compact device.

[0091] The amount of white ink composition applied during the white ink application process is 5.0 mg / inch. 2 The above is preferable. Furthermore, 7.0 mg / inch 2 The above is preferred, with a concentration of 9.0 mg / inch 2 Preferably, it is 10.0 mg / inch 2 It is more preferable that the concentration be greater than or equal to 12.0 mg / inch 2 The above is even more preferable, 15.0 mg / inch 2It is even more preferable that the above conditions are met. In this way, a white image with even better filling and background hiding properties can be obtained.

[0092] Furthermore, the upper limit is 25.0 mg / inch 2 The following is preferred: 20.0 mg / inch 2 The following is more preferable: 15.0 mg / inch 2 The following are even more preferable.

[0093] The amount of white ink composition adhered as described above is the amount in the recording area where the white ink composition and the non-white ink composition are layered and adhered in the recording method of this embodiment. It is also preferable that the maximum amount of white ink composition adhered in that area be within the above range.

[0094] 1.2. Non-white ink application process The non-white ink application process involves applying a non-white ink composition to the recording medium. The method of application to the recording medium will be described later.

[0095] The following is a description of the non-white ink composition. 1.2.1. Non-white colorants A non-white ink composition is a so-called color ink containing a non-white colorant. The non-white colorant contained in the non-white ink composition refers to a colorant other than the white colorant mentioned above. Examples of non-white colorants include dyes and pigments. Preferably, the non-white colorant is a colorant such as cyan, yellow, magenta, or black.

[0096] The non-white colorant may be either a dye or a pigment, or a mixture thereof. However, it is more preferable to include a pigment among the dye and pigment. The pigment has excellent storage stability, such as lightfastness, weather resistance, and gas resistance, and from this viewpoint, it is even more preferable to be an organic pigment.

[0097] Specifically, the pigments used include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelated azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye chelates, dye lakes, nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments, and carbon black. These pigments can be used individually or in combination of two or more. Furthermore, luminous pigments may be used as non-white colorants.

[0098] Examples of pigments, though not limited to them, include the following:

[0099] Examples of black pigments include No.2300, No.900, MCF88, No.33, No.40, No.45, No.52, MA7, MA8, MA100, No.2200B, etc. (all manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (all manufactured by Carbon Columbia), Rega1 400R, Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (manufactured by CABOT JAPAN) KK)), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex Examples include the V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A, and Special Black 4 (all manufactured by Degussa).

[0100] Examples of yellow pigments include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, and 180.

[0101] Examples of magenta pigments include CI Pigment Red 1, 2, 3, 4, 5, and 6. Examples include 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48(Ca), 48(Mn), 57(Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, or CI Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

[0102] Examples of cyan pigments include CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, 66, and CI Bat Blue 4, 60.

[0103] In addition, pigments other than magenta, cyan, and yellow are not particularly limited, but include, for example, CI Pigment Green 7, 10, CI Pigment Brown 3, 5, 25, 26, and CI Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63.

[0104] Pearl pigments are not particularly limited, but examples include titanium dioxide-coated mica, fish scale foil, and bismuth acid chloride, which are pigments that have a pearly or interference luster.

[0105] The metallic pigments are not particularly limited, but examples include particles made from elements or alloys of aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, copper, etc.

[0106] Furthermore, various dyes commonly used for inkjet recording can be used as dyes, such as direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, and reactive disperse dyes.

[0107] The non-white colorant is preferably stably dispersed or dissolved in the dispersion medium, and may be dispersed using a dispersant if necessary. Examples of dispersants include those similar to those used to improve the dispersibility of the white colorant in the white ink composition described above.

[0108] Non-white colorants may be dispersed using a dispersant. A dispersant resin is preferred as the dispersant. The acid value of the dispersant resin for non-white colorants may be the same as that of the dispersant resin for white colorants described above, and is particularly preferred to be 30 mg KOH / g or higher. The acid value of the dispersant resin for non-white colorants is preferably higher than that of the dispersant resin for white colorants, more preferably 5 mg KOH / g or more higher, and even more preferably 10 to 30 mg KOH / g higher. In this case, image quality and other properties are better and therefore preferable.

[0109] The content of the non-white colorant is preferably 0.3% to 20% by mass, more preferably 0.5% to 15% by mass, based on the total mass of the non-white ink composition. Furthermore, 1% to 10% by mass is preferred, and 2% to 7% by mass is more preferred.

[0110] When pigments are used in non-white colorants, the volume-average particle diameter of the pigment particles is preferably 10 nm to 300 nm, more preferably 30 nm to 250 nm, even more preferably 50 nm to 250 nm, and particularly preferably 70 nm to 200 nm. Furthermore, 80 nm to 150 nm is preferred. The volume-average particle diameter of the non-white colorant is measured as an initial state using the volume-average particle diameter confirmation method described above. When the volume-average particle diameter is within the above range, it is preferable in that the desired colorant is easily obtainable and the properties of the colorant are easily improved.

[0111] 1.2.2. Other Ingredients In addition to the non-white colorant, the non-white ink composition may also contain components such as water, resin particles, organic solvents, surfactants, waxes, additives, resin dispersants, preservatives / fungal agents, rust inhibitors, chelating agents, viscosity modifiers, antioxidants, and fungicides.

[0112] The non-white ink composition has components other than the colorant that are the same as those in the white ink composition, and can be selected independently of the white ink composition. These components may all be the same as those in the white ink composition described above, and by reading "white ink composition" as "non-white ink composition," a detailed explanation can be omitted.

[0113] The non-white ink composition is more preferably a water-based ink, and more preferably a water-based resin ink, similar to the white ink composition. This allows for recording with reduced environmental impact and less odor.

[0114] Furthermore, the non-white ink composition preferably contains an organic solvent with a standard boiling point of 150.0°C to 280.0°C, similar to the white ink composition. This allows for faster image fixing during recording.

[0115] Furthermore, it is preferable that the non-white ink composition, like the white ink composition, does not contain more than 1.0% by mass of an organic solvent with a standard boiling point exceeding 280.0°C. This allows for faster image drying and improved image adhesion.

[0116] 1.2.3. Thickness of non-white ink composition It is more preferable that the non-white ink composition exhibits a viscosity increase of 5 times or more when mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:1. Such viscosity-increasing properties ensure sufficient aggregation of the non-white ink composition components upon contact with the processing solution, and also reduce the image quality of the image formed by the non-white ink composition, particularly the thinning of fine lines used for characters, etc. The viscosity increase rate is defined in the same way as for the white ink composition described above.

[0117] The viscosity of the non-white ink composition is preferably 5 times or more, more preferably more than 5 times, more preferably 5.5 times or more, even more preferably 6 times or more, and particularly preferably 7 times or more. Furthermore, 10 times or more is preferred.

[0118] On the other hand, while there is no upper limit to the viscosity of the non-white ink composition, it is preferably 20 times or less, more preferably 10 times or less, more preferably 9 times or less, even more preferably 8.5 times or less, and even more preferably 8 times or less. When the viscosity of the non-white ink composition is within the above range, it is preferable that the image quality, crack resistance, abrasion resistance, and ejection stability are better.

[0119] The viscosity of the non-white ink composition can be adjusted primarily by controlling the type and content of the pigment (including the resin dispersant) and resin particles. The viscosity and surface tension of the non-white ink composition are the same as those of the white ink composition, so a detailed explanation is omitted.

[0120] 1.2.4. Method for applying a non-white ink composition to a recording medium The non-white ink application process can be carried out in any manner as long as the non-white ink composition is applied while scanning the recording medium with an inkjet head. However, it is more preferable to use an inkjet head and eject the non-white ink composition from the inkjet head. This allows for efficient printing of small quantities of various types of ink using a compact device.

[0121] The amount of non-white ink composition applied during the non-white ink application process is 3.0 mg / inch. 2 Preferably, it is 5.0 mg / inch 2 It is more preferable that the above is true, specifically 6.0 mg / inch 2 It is even more preferable that the above is achieved. In this way, a non-white image exhibiting even better color development can be obtained. The upper limit is 15.0 mg / inch. 2 The following is preferred: 10.0 mg / inch 2 The following is more preferable: 7.0 mg / inch 2 The following are even more preferable. The amount of non-white ink composition adhered as described above is the amount in the recording area where the white ink composition and the non-white ink composition are layered and adhered in the recording method of this embodiment. It is also preferable that the maximum amount of non-white ink composition adhered in that area be within the above range.

[0122] Furthermore, it is more preferable that the maximum amount of white ink composition applied in the white ink application step described above is greater than the maximum amount of non-white ink composition applied in the non-white ink application step. This allows for recording with even better background opacity.

[0123] 1.3. First Processing Liquid Application Process The first processing solution application step is a step performed in conjunction with the white ink application step, in which a processing solution containing a coagulant is applied to the recording medium. The processing solution will be described below. The method of application to the recording medium will be described later.

[0124] 1.3.1. Treatment solution The treatment solution contains a coagulant.

[0125] 1.3.1.1. Coagulants The processing solution contains a flocculant that aggregates the components of the ink (white ink composition and non-white ink composition). The flocculant reacts with components such as pigments and resin particles contained in the ink, thereby agglomerating the pigments and resin particles. However, the degree of aggregation of pigments and resin particles by the flocculant varies depending on the type of flocculant, pigment, and resin particles, and can be adjusted. Furthermore, the flocculant can aggregate pigments and resin particles by reacting with them. Such aggregation can, for example, enhance the color development of the pigment, improve the fixation of the resin particles, and / or increase the viscosity of the ink.

[0126] While not particularly limited, examples of flocculants include metal salts, inorganic acids, organic acids, and cationic compounds. Cationic compounds include cationic resins (cationic polymers) and cationic surfactants. Among these, polyvalent metal salts are preferred as metal salts, and cationic resins are preferred as cationic compounds. Therefore, selecting a flocculant from cationic resins, organic acids, and polyvalent metal salts is preferable in terms of obtaining particularly excellent image quality, scratch resistance, gloss, etc.

[0127] While polyvalent metal salts are preferred as the metal salts, other metal salts can also be used. Among these flocculants, it is preferable to use at least one selected from metal salts and organic acids because of its excellent reactivity with the components contained in the ink. Furthermore, among cationic compounds, it is preferable to use cationic resins because they dissolve easily in the treatment solution. It is also possible to use multiple types of flocculants in combination.

[0128] Polyvalent metal salts are compounds composed of metal ions with two or more valencies and anions. Examples of metal ions with two or more valencies include calcium, magnesium, copper, nickel, zinc, barium, aluminum, titanium, strontium, chromium, cobalt, and iron. These include, among the metal ions that make up these polyvalent metal salts, at least one of calcium ions and magnesium ions is preferred because it exhibits excellent aggregation properties for the ink components.

[0129] The anions constituting the polyvalent metal salt are inorganic ions or organic ions. In other words, the polyvalent metal salt in this invention consists of an inorganic ion or organic ion and a polyvalent metal. Examples of such inorganic ions include chloride ions, bromide ions, iodide ions, nitrate ions, sulfate ions, hydroxide ions, etc. Examples of organic ions include organic acid ions, such as carboxylate ions.

[0130] Furthermore, the polyvalent metal compound is preferably an ionic polyvalent metal salt, and in particular, the stability of the treatment solution is better when the polyvalent metal salt is a magnesium salt or a calcium salt. In addition, either an inorganic acid ion or an organic acid ion may be used as the counterion for the polyvalent metal.

[0131] Specific examples of the polyvalent metal salts mentioned above include calcium carbonate such as heavy calcium carbonate and light calcium carbonate, calcium nitrate, calcium chloride, calcium sulfate, magnesium sulfate, calcium hydroxide, magnesium chloride, magnesium carbonate, barium sulfate, barium chloride, zinc carbonate, zinc sulfide, aluminum silicate, calcium silicate, magnesium silicate, copper nitrate, calcium formate, calcium acetate, magnesium acetate, and aluminum acetate. These polyvalent metal salts may be used individually or in combination of two or more. Among these, at least one of calcium formate, magnesium sulfate, calcium nitrate, and calcium chloride is preferred because it ensures sufficient solubility in water and reduces residue left by the treatment solution (making the residue less noticeable), with calcium formate and calcium nitrate being more preferred. These metal salts may also contain hydration water in their raw material form.

[0132] Examples of metal salts other than polyvalent metal salts include monovalent metal salts such as sodium salts and potassium salts, such as sodium sulfate and potassium sulfate.

[0133] Suitable organic acids include, for example, poly(meth)acrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphate, pyrrolidone carboxylic acid, pyrrone carboxylic acid, pyrrole carboxylic acid, furanic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, or derivatives of these compounds, or salts thereof. Organic acids may be used individually or in combination of two or more. Salts of organic acids that are metal salts are included in the above-mentioned metal salts.

[0134] Examples of inorganic acids include sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid. Inorganic acids may be used individually or in combination of two or more.

[0135] Examples of cationic resins (cationic polymers) include cationic urethane resins, cationic olefin resins, cationic amine resins, and cationic surfactants. Cationic polymers are preferably water-soluble.

[0136] As cationic urethane resins, commercially available products can be used, such as Hydran CP-7010, CP-7020, CP-7030, CP-7040, CP-7050, CP-7060, CP-7610 (product names, manufactured by Dainippon Ink and Chemicals, Inc.), Superflex 600, 610, 620, 630, 640, 650 (product names, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and Urethane Emulsion WBR-2120C, WBR-2122C (product names, manufactured by Taisei Fine Chemical Co., Ltd.).

[0137] Cationic olefin resins have olefins such as ethylene and propylene as their structural framework, and known ones can be appropriately selected and used. Cationic olefin resins may also be in an emulsion state dispersed in a solvent such as water or an organic solvent. Commercially available cationic olefin resins can be used, such as Arrowbase CB-1200 and CD-1200 (trade names, manufactured by Unitika Ltd.).

[0138] As cationic amine resins (cationic polymers), any resin having an amino group in its structure is acceptable, and known resins can be appropriately selected and used. Examples include polyamine resins, polyamide resins, and polyallylamine resins. Polyamine resins are resins having an amino group in the main skeleton of the resin. Polyamide resins are resins having an amide group in the main skeleton of the resin. Polyallylamine resins are resins having a structure derived from an allyl group in the main skeleton of the resin.

[0139] Furthermore, examples of cationic polyamine resins include Unisense KHE103L (hexamethylenediamine / epichlorohydrin resin, 1% aqueous solution with a pH of approximately 5.0, viscosity of 20-50 (mPa·s), and solid content of 50% by mass) and Unisense KHE104L (dimethylamine / epichlorohydrin resin, 1% aqueous solution with a pH of approximately 7.0, viscosity of 1-10 (mPa·s), and solid content of 20% by mass) manufactured by Senka Co., Ltd. Furthermore, specific examples of commercially available cationic polyamine resins include FL-14 (manufactured by SNF), Arafix 100, 251S, 255, 255LOX (manufactured by Arakawa Chemical Co., Ltd.), DK-6810, 6853, 6885; WS-4010, 4011, 4020, 4024, 4027, 4030 (manufactured by Seikou PMC Co., Ltd.), and Papiogen P-105 (manufactured by Senka Co., Ltd.). Examples include Sumirez Resin 650(30), 675A, 6615, SLX-1 (manufactured by Taoka Chemical Industry Co., Ltd.), Kachiomaster (registered trademark) PD-1, 7, 30, A, PDT-2, PE-10, PE-30, DT-EH, EPA-SK01, TMHMDA-E (manufactured by Yokkaichi Gosei Co., Ltd.), and Jetfix 36N, 38A, 5052 (manufactured by Satoda Chemical Co., Ltd.).

[0140] Polyamine resins can also be cited as examples of polyamine-based resins. Examples of polyamine resins include polyallylamine hydrochloride, polyallylamineamide sulfate, allylamine hydrochloride / diallylamine hydrochloride copolymer, allylamine acetate / diallylamine acetate copolymer, allylamine acetate / diallylamine acetate copolymer, allylamine hydrochloride / dimethylallylamine hydrochloride copolymer, allylamine / dimethylallylamine copolymer, polydiallylamine hydrochloride, polymethyldiallylamine hydrochloride, polymethyldiallylamineamide sulfate, polymethyldiallylamine acetate, polydiallyldimethylammonium chloride, diallylamine acetate / sulfur dioxide copolymer, diallylmethylethylammonium ethyl sulfate / sulfur dioxide copolymer, methyldiallylamine hydrochloride / sulfur dioxide copolymer, diallyldimethylammonium chloride / sulfur dioxide copolymer, and diallyldimethylammonium chloride / acrylamide copolymer.

[0141] Examples of cationic surfactants include primary, secondary, and tertiary amine salt compounds, alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, quaternary alkylammonium salts, alkylpyridinium salts, sulfonium salts, phosphonium salts, onium salts, and imidazolinium salts.

[0142] Multiple types of these flocculants may be used. Furthermore, selecting at least one of these flocculants—a polyvalent metal salt, an organic acid, or a cationic resin—results in better flocculation, thus enabling the formation of higher-quality images (especially those with good color reproduction).

[0143] The total content of the flocculant in the processing solution is preferably 0.1% to 20% by mass, more preferably 1% to 20% by mass, and more preferably 2% to 15% by mass, relative to the total mass of the processing solution. Even when the flocculant is shared in a solution or dispersion, it is preferable that the solid content is within the above range. If the flocculant content is 1% by mass or more, the ability of the flocculant to flocculate the components contained in the ink is sufficiently obtained. Furthermore, if the flocculant content is 30% by mass or less, the solubility and dispersibility of the flocculant in the processing solution are improved, and the storage stability of the processing solution can be improved.

[0144] Even if the organic solvent contained in the treatment solution has high hydrophobicity, the solubility of the coagulant in the treatment solution will be good. Therefore, it is preferable to use a coagulant that has a solubility of 1 g or more in 100 g of water at 25°C, and more preferably one that is between 3 g and 80 g.

[0145] 1.3.1.2. Other Ingredients The processing solution may contain, in addition to the flocculant, resin particles, water-soluble organic solvents, surfactants, water, wax, additives, resin dispersants, preservatives / fungal agents, rust inhibitors, chelating agents, viscosity modifiers, antioxidants, and fungicides, as long as they do not impair its function. Since these components are the same as those in the white ink composition described above, a detailed explanation is omitted.

[0146] 1.3.2. Physical properties of the treatment solution The processing liquid used in the recording method of this embodiment preferably has a surface tension of 40 mN / m or less, preferably 38 mN / m or less, more preferably 35 mN / m or less, and even more preferably 30 mN / m or less at 25°C, from the viewpoint of ensuring appropriate wetting spread onto the recording medium. The surface tension can be measured by using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) to check the surface tension when a platinum plate is wetted with the composition in an environment of 25°C.

[0147] It is more preferable that the processing solution is applied to the recording medium by an inkjet method. In this case, the viscosity at 20°C is preferably 1.5 mPa·s to 15 mPa·s, more preferably 1.5 mPa·s to 7 mPa·s, and more preferably 1.5 mPa·s to 5.5 mPa·s. When the processing solution is applied to the recording medium by an inkjet method, it is easy to efficiently form a predetermined processing solution application area on the recording medium.

[0148] 1.3.3. Method for applying the processing solution to a recording medium Methods for applying the processing solution to the recording medium include non-contact and contact methods, or combinations thereof, such as inkjet printing, coating with rollers or bars, applying the processing solution to the recording medium using various sprays, immersing the recording medium in the processing solution, and applying the processing solution to the recording medium with a brush. Among these, the inkjet printing method is preferred.

[0149] A mechanism used to apply processing liquid or ink to a recording medium is called an adhesion mechanism. These are the mechanisms that perform each of the adhesion methods described above, such as rollers, inkjet heads, sprays, and brushes.

[0150] The first processing liquid application step is performed in conjunction with the white ink application step. Here, "performed in conjunction with" means that the application of the processing liquid to the recording medium by the first processing liquid application step occurs before or simultaneously with the application of the white ink composition to the recording medium by the white ink application step. That is, after the processing liquid has been applied to the recording medium, or after the processing liquid has been applied to the recording medium Simultaneously with the adhesion, the processing liquid is applied to the recording medium by the first processing liquid application step. Furthermore, one embodiment in which the processing liquid is applied to the recording medium simultaneously with the application of the processing liquid by the first processing liquid application step is to apply the processing liquid to the same scanning area in the same scan (pass) as the scanning (pass) in which the white ink composition is applied to the recording medium. This concept also includes embodiments in which both the processing liquid and the white ink composition are applied to the recording medium in a single "pass" in the recording device described later.

[0151] For example, if the processing liquid application process is performed by an inkjet method, the first processing liquid application process may be performed with the same scanning as the white ink application process, and the second processing liquid application process may be performed with the same scanning as the non-white ink application process.

[0152] Furthermore, "performed incidentally" also means that the process is carried out in such a way that the white ink composition attached to the recording medium by the white ink attachment process and the processing liquid attached to the recording medium by the first processing liquid attachment process can come into contact with and react with the recording medium.

[0153] 1.4. Second Processing Liquid Application Process The second processing liquid application step is a step performed in conjunction with the non-white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. The processing liquid is the same as the processing liquid used in the first processing liquid application step described above, so its explanation is omitted. Note that the processing liquid used in the second processing liquid application step may be the same as or different from the processing liquid used in the first processing liquid application step.

[0154] The adhesion mechanism used in the second treatment liquid adhesion step may be the same as or different from the adhesion mechanism used in the first treatment liquid adhesion step. In other words, the first treatment liquid adhesion step and the second treatment liquid adhesion step may be performed using the same adhesion mechanism.

[0155] The physical properties of the processing liquid used in the second processing liquid application step and the method of applying it to the recording medium are the same as those of the processing liquid used in the first processing liquid application step. The second processing liquid application step is performed in conjunction with the non-white ink application step. The fact that it is performed in conjunction with the second processing liquid application step is the same as that of the first processing liquid application step described above. The second processing liquid application step is performed after the white ink application step.

[0156] Furthermore, the surface tension of the processing liquid used in each processing liquid application step may be made lower than the surface tension of the non-white ink composition, and the surface tension of the non-white ink composition may be made lower than the surface tension of the white ink composition. In this way, the processing liquid spreads more easily on the substrate, and the white ink on top of it also spreads more easily, thus improving filling and pinholes. Moreover, since the non-white ink composition spreads more easily than the white ink composition, it is easier to form a non-white image on a white image.

[0157] 1.5. Amount of adhesion in each process In the recording method of this embodiment, the amount of processing liquid applied in the second processing liquid application step is set to be less than the amount of processing liquid applied in the first processing liquid application step. If the amount of processing liquid applied in the second processing liquid application step is too large, the aggregation of components of the non-white ink composition may progress too much, which may cause thinning of lines in the image. Also, some of the processing liquid used when applying the white ink composition remains in the second processing liquid application step. Therefore, by reducing the amount of processing liquid applied in the second processing liquid application step, the aggregation of components of the non-white ink composition can be suppressed, the thinning of lines in the image can be reduced, and bleeding unevenness can be suppressed.

[0158] Furthermore, the amount of processing liquid applied in the first processing liquid application process and the amount of processing liquid applied in the second processing liquid application process are recorded in the same recording area in which the first and second processing liquid application processes are performed.

[0159] The amount of processing liquid applied in the first processing liquid application process is 0.1 mg / inch 2 The above 4.0 mg / inch 2 The following is preferable. Furthermore, 0.5 mg / inch 2 The above 3.0 mg / inch 2 Preferably, it is 0.4 mg / inch 2 More than 2.5mg / inch 2 The following is more preferable: 0.5 mg / inch 2 The above 2.0 mg / inch 2 It is even more preferable that the following conditions be met: 0.8 mg / inch 2 More than 1.5mg / inch 2 The following is even more preferable. The maximum amount of processing liquid applied in the first processing liquid application step may be within the above range. In this way, it is possible to further reduce bleed unevenness and thinning of fine lines in images caused by the non-white ink composition while maintaining sufficiently high image quality with the white ink composition.

[0160] Furthermore, the amount of processing liquid applied in the second processing liquid application process is 2.5 mg / inch. 2 Preferably, it is 0.05 mg / inch 2 More than 2.3mg / inch2 It is more preferable that the following conditions apply: 0.1 mg / inch 2 More than 2.2mg / inch 2 The following is more preferable. Furthermore, 0.2 mg / inch 2 The above 2.0 mg / inch 2 It is more preferable that the following be the case: 0.4 mg / inch 2 More than 1.5mg / inch 2 It is even more preferable that the following conditions be met: 0.5 mg / inch 2 The above 1.0 mg / inch 2 The following is even more preferable. The maximum amount of processing liquid applied in the second processing liquid application step may be within the above range. This further reduces image bleeding unevenness and thinning of fine lines caused by the non-white ink composition.

[0161] Furthermore, the total amount of processing liquid applied in the first processing liquid application step and the processing liquid applied in the second processing liquid application step is 4.0 mg / inch. 2 Preferably, it is 0.1 mg / inch 2 More than 3.8mg / inch 2 The following is more preferable. Furthermore, 0.5 mg / inch 2 More than 3.5mg / inch 2 It is more preferable that the following conditions be met: 0.8 mg / inch 2 More than 2.5mg / inch 2 It is even more preferable that the following conditions apply: 1.0 mg / inch 2 The above 2.0 mg / inch 2 It is even more preferable that the following conditions are met. In this way, the lack of image coverage due to the white ink composition can be further suppressed, and the image coverage due to the non-white ink composition can be improved.

[0162] Furthermore, in the areas where white and non-white colorants are attached, the amount of processing liquid attached to the recording medium may be constant or vary depending on the location. In particular, the amount of processing liquid attached may vary depending on the location depending on the amount of non-white ink composition attached. However, in the recording method of this embodiment, in any location (recording area) where recording is performed in the recording method, the amount of processing liquid attached in the second processing liquid attachment step in the same recording area is made smaller than the amount of processing liquid attached in the first processing liquid attachment step.

[0163] For example, even in a recording area where the amount of processing liquid applied in the second processing liquid application process is the maximum, the amount of processing liquid applied in the second processing liquid application process is kept smaller than the amount of processing liquid applied in the first processing liquid application process. Furthermore, even in a recording area where the amount of processing liquid applied in the second processing liquid application process is the maximum and the amount of processing liquid applied in the first processing liquid application process is the minimum, the amount of processing liquid applied in the second processing liquid application process in the same recording area is kept smaller than the amount of processing liquid applied in the first processing liquid application process.

[0164] The ratio (mass ratio) of the amount of processing liquid deposited in the second processing liquid deposition step to the amount of processing liquid deposited in the first processing liquid deposition step is less than 1, preferably 0.1 or more and 0.9 or less, more preferably 0.2 or more and 0.5 or less, even more preferably 0.3 or more and 0.49 or less, and particularly preferably 0.4 or more and 0.47 or less. In this case, image quality and other aspects are better and therefore preferable.

[0165] 1.6. Mass of droplets in each step When the first and second processing liquid application steps are performed by an inkjet method, the mass of the multiple droplets of processing liquid in the first and second processing liquid application steps is preferably 10 ng or less. More preferably, it is 7 ng or less. This increases the opportunities for contact between the processing liquid and the ink on the recording medium.

[0166] From this perspective, the mass of the multiple droplets of the processing liquid in the first and second processing liquid application steps is more preferably 5 ng or less, even more preferably 4 ng or less, and even more preferably 3 ng or less. Also, 1 ng or more is preferred.

[0167] Here, the droplet mass refers to the mass of a single droplet ejected from the inkjet head. It is also called the droplet dot mass.

[0168] When the white ink application process and the non-white ink application process are performed in a single scan together with the first and second processing liquid application processes, the timing at which the white ink composition, non-white ink composition, and processing liquid land on the same location in the same area during a single scan may differ, but the time difference is very small. However, the order in which the white ink composition, non-white ink composition, and processing liquid land on the same location in the same area during a single scan is not particularly limited.

[0169] In the recording method of this embodiment, recording may be performed by repeatedly performing an inkjet head scan (main scan) and a sub-scan, which changes the relative position of the inkjet head and the recording medium in a direction intersecting the scanning direction, as in the inkjet recording apparatus described later. Recording may also be performed by repeatedly performing these operations alternately. Furthermore, in the sub-scan after the main scan, the relative position between the inkjet head and the recording medium may be moved in the sub-scan direction by a length shorter than the length of the nozzle row of the inkjet head, and the area scanned in the previous main scan may be scanned in the next main scan. In this case, ink or processing liquid is applied to an area where ink or processing liquid is applied by the nozzle row of the inkjet head in one scan, and then again in another scan. In other words, the nozzle row of the inkjet head may be applied to an area of ​​the recording medium where the nozzle row of the inkjet head is facing in one scan, and then again in another scan.

[0170] Sub-scanning may be performed by moving the recording medium relative to the inkjet head, or by moving the inkjet head relative to the recording medium.

[0171] Thus, in recording, there may be areas on the recording medium where ink or processing liquid adheres with a single scan of the inkjet head, and areas where the same ink or processing liquid adheres with a further scan. In other words, there may be areas where the same area is scanned two or more times. The number of times the same area is scanned is called the number of scans (number of scans, number of passes). The number of scans is the number per ink.

[0172] The number of scans is 1 or more, preferably 2 or more, and more preferably 4 or more. It is also preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. Furthermore, it is preferably 4 or less, and more preferably 2 or less.

[0173] When the number of scans exceeds the above range, it is preferable to have better reductions in density unevenness and image quality differences. When the number of scans is below the above range, it is preferable to have better printing speed.

[0174] The number of scans depends on the configuration of the recording device, but can be calculated as follows: The number of scans is obtained by dividing the length of the inkjet head in the sub-scanning direction by the distance of one sub-scan in the sub-scanning direction of the recording medium.

[0175] In the recording method of this embodiment, when scanning as described above, by appropriately arranging and controlling the ejection of nozzles that eject the white ink composition, nozzles that eject the non-white ink composition, and nozzles that eject the processing liquid of the inkjet head, it is possible to form an area within the recording area of ​​the recording medium in one main scan in which the white ink composition lands before the non-white ink composition.

[0176] 1.7. Other processes The recording method of this embodiment includes the steps of applying a processing liquid, a white ink composition, and a non-white ink composition to a recording medium. However, if necessary, it may also include the step of applying one or more of the processing liquid, white ink composition, and non-white ink composition to the recording medium. Furthermore, there are no restrictions on the order or number of times these steps are performed, and they can be performed as appropriate as needed. In addition, it is preferable that the processing liquid and inks are applied to the same area on the recording medium.

[0177] The recording method of this embodiment may include a drying step (primary heating step) for drying the liquid adhering to the recording medium, a step (post-heating step) for heating the recording medium, and so on.

[0178] 1.7.1.Drying process The recording method of this embodiment may include a drying step (primary heating step). The recording method according to this embodiment may include a step of drying the recording medium before or during the process of applying the processing liquid or ink composition. The drying step can be carried out by stopping the recording and leaving it, or by using a drying mechanism. Examples of means for drying using a drying mechanism include means for blowing room temperature air or hot air onto the recording medium (air blowing type), means for irradiating the recording medium with heat-generating radiation (infrared rays, etc.) (radiation type), a member that contacts the recording medium and transfers heat to the recording medium (conduction type), and combinations of two or more of these means. If a drying step is included, it is more preferable to carry it out using the air blowing method.

[0179] In the drying process (primary drying process), when a drying mechanism that heats the recording medium is used as the drying mechanism, it is specifically called the heating process (primary heating process). For example, among the drying mechanisms mentioned above, a drying process that uses room temperature airflow does not fall under the category of a heating process.

[0180] The surface temperature of the recording medium when the processing liquid or ink composition is applied is preferably 45°C or lower, more preferably 20°C to 45°C. Furthermore, it is preferably 27.0°C to 40°C, and more preferably 28°C to 30°C. This temperature is the surface temperature of the portion of the recording surface of the recording medium that receives liquid application during the application process, and represents the highest temperature in the recording area during the application process. A surface temperature within the above range is more preferable in terms of image quality, scratch resistance, and clogging reduction.

[0181] The drying process can be performed simultaneously with one or more of the processing liquid application process and the ink application process described above. When the drying process is performed simultaneously with the ink application process, the surface temperature of the recording medium is preferably 30°C or lower, and more preferably 28°C or lower.

[0182] When a drying step is performed to dry the recording medium before or during the processing liquid application step, the surface temperature of the recording medium at the time the processing liquid adheres to the recording medium is preferably 30.0°C or higher, preferably 35.0°C or higher, and more preferably 40.0°C or higher. This makes it easier for a film to form with the processing liquid, especially when the processing liquid contains resin particles, which can further improve the adhesion and scratch resistance of the resulting image.

[0183] Furthermore, each adhesion step does not necessarily require a primary heating step. This allows for even better ejection stability of each ink, etc. Moreover, each adhesion step does not require a primary drying step. It doesn't need to be to an extent.

[0184] 1.7.2. Post-heating process The recording method according to this embodiment may include a post-heating step in which the recording medium is further heated after each of the above adhesion steps. The post-heating step can be carried out, for example, using an appropriate heating means. The post-heating step can be carried out, for example, by an afterheater (in the example of the inkjet recording device described later, this corresponds to heating heater 5). Furthermore, the heating means is not limited to the heating means provided in the inkjet recording device, but other drying means can also be used. This dries the resulting image and allows it to be fixed more thoroughly, so for example, the recorded material can be made usable sooner.

[0185] The temperature of the recording medium in this case is not particularly limited, but can be set considering, for example, the Tg of the resin components constituting the resin particles contained in the recording material. When considering the Tg of the resin components constituting the resin particles or wax, it is preferable to set the temperature to 5.0°C or higher, preferably 10.0°C or higher, than the Tg of the resin components constituting the resin particles.

[0186] The surface temperature of the recording medium reached by the post-heating step is 30.0°C to 120.0°C, preferably 40.0°C to 100.0°C, more preferably 50.0°C to 95°C, and even more preferably 70°C to 90°C. The surface temperature of the recording medium reached by the post-heating step is particularly preferably 80°C or higher. When the temperature of the recording medium is within this range, the resin particles and wax contained in the recording material can be film-formed and planarized, and the resulting image can be dried and fixed more sufficiently.

[0187] 1.8. Effects According to the recording method of this embodiment, the processing liquid is applied not only in the first processing liquid application step associated with the application of the white ink composition, but also in the second processing liquid application step associated with the application of the non-white ink composition. Therefore, the image quality of the image formed by the white ink composition can be improved, and bleed unevenness in the image formed by the non-white ink composition can be suppressed.

[0188] Furthermore, since the amount of processing liquid applied in the second processing liquid application step is smaller than the amount applied in the first processing liquid application step, the amount of processing liquid applied in the second processing liquid application step does not become excessive compared to the amount needed to aggregate the components of the non-white ink composition. As a result, the aggregation of the components of the non-white ink composition does not progress too much, and thus the thinning of image lines caused by the non-white ink composition can be suppressed.

[0189] 1.9. Recording media The recording medium used to form an image by the recording method according to this embodiment may or may not have a recording surface that absorbs ink. Therefore, there are no particular limitations on the recording medium, and examples include liquid-absorbent recording media such as paper, film, and cloth; low-liquid-absorbent recording media such as printing paper; and liquid-non-absorbent recording media such as metal, glass, and polymers.

[0190] A liquid-low absorption or liquid-non-absorbent recording medium refers to a recording medium that does not absorb ink at all or absorbs very little ink. Quantitatively, a liquid-non-absorbent or liquid-low absorption recording medium is defined as "a recording medium that absorbs ink within 30 msec from the start of contact in the Bristow method." 1 / 2 Up to 10 mL / m² of water absorption capacity 2 This refers to the recording medium described below. The Bristow method is the most widely used method for measuring liquid absorption in a short time and is also adopted by the Japan Paper & Pulp Technology Association (JAPAN TAPPI). For details of the test method, please refer to standard No. 51 "Paper and cardboard - Liquid absorption" in the "JAPAN TAPPI Paper & Pulp Test Methods 2000 Edition". This is described in "Absorption Test Method - Bristow Method". In contrast, a liquid-absorbent recording medium refers to a recording medium that does not fall under the categories of liquid-non-absorbent or liquid-low absorbent. In this specification, liquid-low absorbency and liquid non-absorbency may be simply referred to as low absorbency and non-absorbency, respectively.

[0191] Examples of liquid-non-absorbent recording media include those coated with plastic on a substrate such as paper, those with a plastic film bonded to a substrate such as paper, and plastic films without an absorbent layer (receiving layer). Examples of plastics in this context include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

[0192] Furthermore, examples of low-liquid-absorption recording media include recording media having a low-liquid-absorption coating layer on their surface. These are known as coated paper. For example, when the substrate is paper, examples include printing paper such as art paper, coated paper, and matte paper. When the substrate is plastic film, examples include those coated with polymers on the surface of polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc., or those coated with silica, titanium, or other particles together with a binder.

[0193] Liquid-absorbing recording media can also be used as recording media. In the Bristow method described above, the liquid-absorbing recording media is used from the start of contact for 30 msec. 1 / 2 Up to 10 mL / m² of water absorption capacity 2 It refers to a "super recording medium."

[0194] Examples of liquid-absorbing recording media include those that have a liquid-absorbing receiving layer on their surface. For example, inkjet paper (paper specifically for inkjet printers) is one such example. The liquid-absorbing receiving layer may be composed of a liquid-absorbing resin, a liquid-absorbing inorganic fine particle, or the like.

[0195] Examples of liquid-absorbent recording media include those in which the substrate itself is liquid-absorbent. Examples include fabrics made of fibers and paper made from pulp. Examples of paper include ordinary paper, cardboard, and liner paper. Liner paper can be made from kraft pulp, recycled paper, etc.

[0196] 2. Inkjet recording device The recording device according to this embodiment comprises an adhesion mechanism for performing the white ink adhesion step, an adhesion mechanism for performing the non-white ink adhesion step, an adhesion mechanism for performing the first processing liquid adhesion step, and an adhesion mechanism for performing the second processing liquid adhesion step, and performs any of the above recording methods.

[0197] Hereinafter, an example of an inkjet recording apparatus capable of implementing the recording method according to this embodiment will be described with reference to the drawings.

[0198] Figure 1 is a schematic cross-sectional view illustrating an inkjet recording device. Figure 2 is a perspective view showing an example of the configuration around the carriage of the inkjet recording device 1 in Figure 1. As shown in Figures 1 and 2, the inkjet recording device 1 comprises an inkjet head 2, an IR heater 3, a platen heater 4, a heating heater 5, a cooling fan 6, a preheater 7, a blower 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 device 1 is controlled by the control unit CONT shown in Figure 2.

[0199] The inkjet recording device 1 in Figure 1 records by performing multiple main scans and multiple sub-scans. This is a serial recording device in which scanning is performed. Scanning is also called main scanning. Serial recording devices are preferable to line recording devices (described later) because they can be made smaller.

[0200] The inkjet head 2 is configured to record onto the recording medium M by ejecting ink or processing liquid from its nozzles and applying it to the recording medium M. In this embodiment, the inkjet head 2 is a serial inkjet head, and it applies ink or processing liquid to the recording medium M by scanning it multiple times in the main scanning direction relative to the recording medium M. The inkjet head 2 is mounted on the carriage 9 shown in Figure 2. The inkjet head 2 is scanned multiple times in the main scanning direction relative to the recording medium M by the operation of the carriage movement mechanism 13, which moves the carriage 9 in the media width direction of the recording medium M. The media width direction is the main scanning direction of the inkjet head 2. Scanning in the main scanning direction is also called main scanning.

[0201] Here, the main scanning direction is the direction in which the carriage 9, equipped with the inkjet head 2, moves. In Figure 1, this direction intersects with the sub-scanning direction, which is the transport direction of the recording medium M indicated by arrow SS. In Figure 2, the width direction of the recording medium M, i.e., the direction represented by S1-S2, is the main scanning direction MS, and the direction represented by T1→T2 is the sub-scanning direction SS. Note that in one scan, scanning is performed in the main scanning direction, i.e., in either the direction of arrow S1 or arrow S2. Then, by repeatedly performing the main scan of the inkjet head 2 and the sub-scan, which is the transport of the recording medium M, multiple times, data is recorded on the recording medium M.

[0202] The cartridge 12 that supplies ink and processing fluid to the inkjet head 2 includes a plurality of independent cartridges. The cartridge 12 is detachably mounted on the carriage 9 on which the inkjet head 2 is mounted. Each of the plurality of cartridges is filled with ink and processing fluid, and the predetermined ink and processing fluid are supplied from the cartridge 12 to each nozzle. In this embodiment, the example shown is that the cartridge 12 is mounted on the carriage 9, but it is not limited to this, and may be provided in a location other than the carriage 9 and supplied to each nozzle by a supply pipe (not shown). Furthermore, the nozzles from which ink is ejected and the nozzles from which processing fluid is ejected can be appropriately designed in conjunction with the arrangement of the cartridge 12. In addition, multiple inkjet heads 2 may be mounted on the cartridge 12.

[0203] Conventional known methods can be used for ejection from the inkjet head 2. In this embodiment, a method is used that ejects droplets using the vibration of a piezoelectric element, that is, an ejection method that forms ink droplets by the mechanical deformation of an electrostrictive element.

[0204] When the above-mentioned white ink composition, non-white ink composition, and processing liquid are ejected from the inkjet head 2, the inkjet head 2 constitutes a part of an adhesion mechanism that performs a white ink adhesion process and an adhesion mechanism that performs a non-white ink adhesion process, as well as an adhesion mechanism that performs a first processing liquid adhesion process and an adhesion mechanism that performs a second processing liquid adhesion process.

[0205] The inkjet recording device 1 is equipped with an IR heater 3 and a platen heater 4 for heating the recording medium M when ink or processing liquid is ejected from the inkjet head 2. In this embodiment, when drying the recording medium M in the drying process, a drying mechanism such as the IR heater 3, blower fan 8, platen heater 4, and preheater 7 can be used. The drying process performed on the ink that adheres to the recording medium when ink is applied is also called the primary drying process.

[0206] Furthermore, by using the IR heater 3, the recording medium M can be heated radiantly by infrared radiation from the inkjet head 2 side. This makes it easier for the inkjet head 2 to be heated at the same time, but the temperature can be raised without being affected by the thickness of the recording medium M, compared to when the recording medium M is heated from the back side by a platen heater 4 or the like. The recording medium M may also be equipped with various fans (e.g., a blower fan 8) that blow air at the same temperature onto the recording medium M to dry the ink and non-white ink on the recording medium M.

[0207] The platen heater 4 can heat the recording medium M via the platen 11 at a position facing the inkjet head 2 so that the ink and processing liquid ejected by the inkjet head 2 can dry quickly from the moment they adhere to the recording medium M. The platen heater 4 is capable of heating the recording medium M by conduction and, as described above, is used as needed in the recording method of this embodiment. When used, it is preferable to control the surface temperature of the recording medium M to be 40.0°C or lower.

[0208] In the ink application process, a drying step for drying the ink applied to the recording medium by a drying mechanism may be omitted, or the drying step may be performed at a relatively low temperature. In this case, the rapid drying of the ink applied to the recording medium is suppressed, resulting in better filling and other desirable properties.

[0209] When the recording medium M is dried or not dried by a drying mechanism during the ink application process, the upper limit of the surface temperature of the recording medium M is preferably 45.0°C or lower, more preferably 40.0°C or lower, even more preferably 38.0°C or lower, and particularly preferably 35.0°C or lower. Furthermore, it is preferably 30°C or lower, 28°C or lower, and 25°C or lower. The lower limit of the surface temperature of the recording medium M is preferably 20°C or higher, preferably 25.0°C or higher, more preferably 28.0°C or higher, even more preferably 30.0°C or higher, and particularly more preferably 32.0°C or higher. It is also preferable to use a temperature at which the recording medium is not heated by the drying mechanism described above.

[0210] When the temperature is below the above range, drying and compositional changes of the ink and processing liquid inside the inkjet head 2 can be suppressed, and the welding of resin particles, etc., to the inner wall of the inkjet head 2 can be suppressed. Furthermore, the filling, color development, and image quality differences are better and preferable. When the temperature is above the above range, the ink and processing liquid can be fixed on the recording medium M earlier, and the image quality can be improved. Note that the above temperature is the highest temperature at the location on the recording medium surface facing the inkjet head during the ink or processing liquid adhesion process.

[0211] The heating element 5 is a heater for drying and solidifying the ink attached to the recording medium M, that is, a heater for secondary heating or secondary drying. The heating element 5 can be used in a post-heating process. When the heating element 5 heats the recording medium M on which the image is recorded, water and other substances contained in the liquid evaporate more quickly and are scattered, and an ink film is formed by the resin contained in the liquid. In this way, the ink film is firmly fixed or adhered to the recording medium M, resulting in excellent film-forming properties, and a high-quality image can be obtained in a short time. The upper limit of the surface temperature of the recording medium M by the heating element 5 is preferably 120.0°C or less, more preferably 100.0°C or less, and even more preferably 90.0°C or less. The lower limit of the surface temperature of the recording medium M is preferably 60.0°C or higher, more preferably 70.0°C or higher, and even more preferably 80.0°C or higher. By keeping the temperature within the above range, a high-quality image can be obtained in a short time. Note that the above temperatures are the highest temperatures of the portion of the recording medium that receives secondary heating during recording.

[0212] The inkjet recording device 1 may have a cooling fan 6. After the ink recorded on the recording medium M dries, the ink on the recording medium M is cooled by the cooling fan 6, thereby forming an ink coating film with good adhesion on the recording medium M.

[0213] Furthermore, the inkjet recording device 1 records before ink is applied to the recording medium M. It may also be equipped with a preheater 7 for preheating the recording medium M.

[0214] Below the carriage 9 are 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 transport means 14 which is a roller that transports the recording medium M in the sub-scanning direction. The operation of the carriage movement mechanism 13 and the transport means 14 is controlled by the control unit CONT.

[0215] Figure 3 is a functional block diagram of the inkjet recording device 1. The control unit CONT is a control unit for controlling the inkjet recording device 1. The interface unit 101 (I / F) is for sending and receiving data between the computer 130 (COMP) and the inkjet recording device 1. The CPU 102 is an arithmetic processing unit for controlling the entire inkjet recording device 1. The memory 103 (MEM) is for reserving an area for storing the CPU 102's program and a work area. The CPU 102 controls each unit by the unit control circuit 104 (UCTRL). The detector group 121 (DS) monitors the status inside the inkjet recording device 1, and the control unit CONT controls each unit based on the detection results.

[0216] The transport unit 111 (CONVU) controls the sub-scanning (transport means) of inkjet recording, and specifically controls the transport direction and transport speed of the recording medium M. Specifically, it controls the transport direction and transport speed of the recording medium M by controlling the rotation direction and rotation speed of the transport rollers driven by the motor.

[0217] The carriage unit 112 (CARU) controls the main scan (pass) (scanning means) of inkjet recording, and specifically moves the inkjet head 2 back and forth in the main scan direction. The carriage unit 112 comprises a carriage 9 on which the inkjet head 2 is mounted, and a carriage movement mechanism 13 for moving the carriage 9 back and forth.

[0218] The head unit 113 (HU) controls the amount of ink or processing liquid ejected from the nozzles of the inkjet head 2. For example, if the nozzles of the inkjet head 2 are driven by piezoelectric elements, the head unit 113 controls the operation of the piezoelectric elements in each nozzle. The head unit 113 controls the timing of the adhesion of each liquid, the dot size and mass of the ink or processing liquid, etc. Furthermore, the amount of ink or processing liquid deposited per scan is controlled by the combination of control of the carriage unit 112 and the head unit 113.

[0219] The drying unit 114 (DU) controls the temperatures of various heaters, including the IR heater 3, preheater 7, platen heater 4, and heating heater 5.

[0220] The inkjet recording device 1 described above alternately repeats the operation of moving the carriage 9, on which the inkjet head 2 is mounted, in the main scanning direction (main scanning) and the transport operation (sub-scanning). At this time, the control unit CONT controls the carriage unit 112 to move the inkjet head 2 in the main scanning direction when performing each pass, and also controls the head unit 113 to eject droplets of ink or processing liquid from predetermined nozzle holes of the inkjet head 2, thereby adhering the droplets of ink or processing liquid to the recording medium M. Furthermore, the control unit CONT controls the transport unit 111 to transport the recording medium M in the transport direction at a predetermined transport amount (feed amount) during the transport operation.

[0221] In the inkjet recording device 1, the nozzles of the inkjet head 2 are arranged in rows, for example, and each row can be assigned a predetermined ink or processing liquid. Furthermore, the presence or absence of ejection and the timing of ejection may be controlled within the row of nozzles. Multiple inkjet heads 2 may be mounted on the 7x9, and even in this case, the presence or absence of ejection and the timing of ejection for each inkjet head 2 can be controlled.

[0222] Figure 4 shows an example of the configuration of the inkjet head of a recording device that performs the recording method of this embodiment. Figure 4(1) is one example, and is a view of the entire inkjet head of Figure 1 from below. The entire inkjet head (square frame) has an inkjet head R for the processing liquid, an inkjet head W for the white ink composition, and an inkjet head C for the non-white ink composition arranged in the main scanning direction (horizontal direction in the figure). Each inkjet head has a nozzle row in which multiple nozzles are arranged in the sub-scanning direction SS. The number of nozzle rows per inkjet head is not limited to two rows as shown in the figure, but can be one or more. The portion of the nozzle row of each inkjet head used for recording is enclosed by a dotted line. By performing the main scan and sub-scan in sequence, as recording progresses, the processing liquids and ink compositions are applied to the same scanning area of ​​the recording medium in the following order: the area enclosed by the dotted line upstream of the processing liquid inkjet head R in the sub-scanning direction, the area enclosed by the dotted line of the white ink composition inkjet head W, the area enclosed by the dotted line downstream of the processing liquid inkjet head R in the sub-scanning direction, and the area enclosed by the dotted line of the non-white ink composition inkjet head C. The first processing liquid application process is performed in the area enclosed by the dotted line upstream of the processing liquid inkjet head R in the sub-scanning direction, and the second processing liquid application process is performed in the area enclosed by the dotted line downstream of the processing liquid inkjet head R in the sub-scanning direction.

[0223] Figure 4(2) shows an example of an inkjet head configuration different from that of Figure 4(1). Similar to Figure 4(1), the white ink application process is performed by the portion of the white ink composition inkjet head W enclosed by the dotted line. In addition, the first processing liquid application process is performed by the portion of the processing liquid inkjet head R whose position overlaps with the portion of the white ink composition inkjet head W enclosed by the dotted line when projected in the main scanning direction, using the same main scan as the white ink application process. As recording progresses by performing the main and sub-scans in sequence, the non-white ink application process is performed by the portion of the non-white ink composition inkjet head C enclosed by the dotted line. In addition, the second processing liquid application process is performed by the portion of the processing liquid inkjet head R whose position overlaps with the portion of the non-white ink composition inkjet head C enclosed by the dotted line when projected in the main scanning direction, using the same main scan as the non-white ink application process.

[0224] Figure 4(3) shows another example of an inkjet head configuration. The entire inkjet head for the white ink composition performs the white ink application process. The entire inkjet head R for the processing solution performs the first processing solution application process with the same main scan as the white ink application process. Subsequently, the entire inkjet head C for the non-white ink composition performs the non-white ink application process. The entire inkjet head R for the processing solution also performs the second processing solution application process with the same main scan as the non-white ink application process. Sub-scanning may be omitted between the white ink application process and the non-white ink application process, or sub-scanning may be performed for image alignment. Sub-scanning may be performed after the non-white ink application process.

[0225] In the example in Figure 4, recording was performed by limiting the portion of each inkjet head used for recording. However, the inkjet heads could also be limited to the area enclosed by the dotted line in Figure 4. In other words, the portion of each inkjet head used for recording could be considered as the inkjet head itself.

[0226] The recording method of this embodiment may be performed using a line-type recording device, in addition to the serial-type recording device as in the example described above.

[0227] Figure 5 shows an example of a line-type recording device. In the inkjet recording device 1 shown in Figure 5, the recording medium 10 is transported in the transport direction by the recording medium support means 15 and transport rollers 16 and 17. As recording progresses on the transported recording medium, the following processes are carried out in order: a first processing liquid application process by the inkjet head 2a, a white ink application process by the inkjet head 2b, a second processing liquid application process by the inkjet head 2c, and a non-white ink application process by the inkjet head 2d. Line-type recording devices are preferable because they allow for faster recording speeds compared to the serial-type recording devices described above.

[0228] An example of the arrangement and settings of the inkjet head for executing the recording method of this embodiment will be shown in the "Examples" section below. For example, in the above recording method, the white ink application process can be set to be performed in one scan for areas where ink can be applied in one scan, and the non-white ink application process can be set to be performed in one scan for areas where ink can be applied in one scan. In this way, recording can be performed at a better recording speed.

[0229] Furthermore, in the above recording method, the first processing liquid application step can be set to be performed with the same scanning as the white ink application step, and the second processing liquid application step can be set to be performed with the same scanning as the non-white ink application step. In this way, recording can be performed at a better recording speed.

[0230] According to the recording device of this embodiment, the processing liquid is applied not only in the first processing liquid application step associated with the application of the white ink composition, but also in the second processing liquid application step associated with the application of the non-white ink composition. Therefore, the image quality of the image formed by the white ink composition can be improved, and bleed unevenness in the image formed by the non-white ink composition can be suppressed.

[0231] Furthermore, since the amount of processing liquid applied in the second processing liquid application step is smaller than the amount applied in the first processing liquid application step, the amount of processing liquid applied in the second processing liquid application step does not become excessive compared to the amount needed to aggregate the components of the non-white ink composition. As a result, the aggregation of the components of the non-white ink composition does not progress too much, and thus the thinning of image lines caused by the non-white ink composition can be suppressed.

[0232] 3. Examples and Comparative Examples The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" refer to mass unless otherwise specified. Unless otherwise specified, evaluations were performed in an environment with a temperature of 25.0°C and a relative humidity of 40.0%.

[0233] 3.1. Preparation of ink and processing solution Each component was placed in a container to achieve the composition shown in Table 1, mixed and stirred with a magnetic stirrer for 2 hours, and then thoroughly mixed by dispersion treatment in a bead mill filled with 0.3 mm diameter zirconia beads. After stirring for 1 hour, the mixture was filtered using a 5.0 μm PTFE membrane filter to obtain white ink compositions (W1-W4), non-white ink compositions (C1, C2), and treatment solutions (R1-R3). The values ​​in Table 1 represent mass percent. Pure water was used, and it was added so that the mass of each ink was 100% by mass. Pigments and dispersant resins were prepared using the dispersion solutions described later.

[0234] [Table 1]

[0235] Of the components shown in Table 1, those other than the compound names are as follows: • Cationic polymer: "Catiomaster PD-7, polyamine resin (epichlorohydrin) - Amine derivative resin) Manufactured by Yokkaichi Gosei Co., Ltd. • Dispersant resin, resin A (anionic): Acrylic acid-acrylic acid ester copolymer (weight-average molecular weight: 25,000, acid value: 25) • Dispersant resin, resin B (nonionic): Acrylic acid-acrylic acid ester copolymer (weight-average molecular weight: 25,000, acid value: 0) • Dispersant resin, resin C (anionic): Acrylic acid-acrylic acid ester copolymer (weight-average molecular weight: 25,000, acid value: 35) • Carbon black: No. 33 (manufactured by Mitsubishi Chemical Corporation) • Resin particles, styrene-acrylic A: See below (high cohesiveness) • Resin particles, styrene-acrylic type B: See below (low cohesiveness) • Wax, polyethylene-based: "Nopcoat PEM-17" (product name, manufactured by Sunopco Co., Ltd.) • Surfactant: Silicone-based surfactant "BYK348" manufactured by BYK Corporation.

[0236] (Preparation of resin particles: styrene-acrylic B) Resin emulsion B (acid value 7 mg KOH / g) was obtained by emulsifying copolymerization of 75 parts by mass of styrene, 0.8 parts by mass of acrylic acid, 14.2 parts by mass of methyl methacrylate, and 10 parts by mass of cyclohexyl methacrylate. Newcol NT-30 (manufactured by Nippon Emulsifier Co., Ltd.) was used as the surfactant for emulsion polymerization, and the amount used was 2 parts by mass, relative to the total amount of monomers at 100 parts by mass.

[0237] (Preparation of resin particles: styrene-acrylic A) Resin emulsion A (acid value 30 mg KOH / g) was obtained in the same manner as above, except that the monomer composition was changed. The surfactant for emulsion polymerization was added in an amount of 1 part by mass per 100 parts by mass of the total amount of monomer.

[0238] (Preparation of pigment dispersion) <Dispersion of white pigment using resin A> First, 12 parts by mass of an anionic acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, acid value: 25) as a resin dispersant was added to and dissolved in 155 parts by mass of ion-exchanged water in which 0.1 part by mass of a 30% aqueous ammonia solution (neutralizing agent) was dissolved. 40 parts by mass of titanium dioxide (C.I. Pigment White 6), which is a white pigment, was added thereto, and dispersion treatment was performed for 10 hours using a ball mill with zirconia beads. Then, centrifugal filtration was performed using a centrifuge to remove impurities such as coarse particles and dust, and the concentration of the white pigment was adjusted to 20% by mass to obtain a white colorant dispersion liquid. The particle size of the white pigment was 350 nm in terms of average particle size.

[0239] <White Pigment Dispersion Liquid by Resin B> A white colorant dispersion liquid was obtained in the same manner except that an acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, acid value: 0) was used as the resin dispersant. The particle size of the white pigment was 350 nm in terms of average particle size.

[0240] <Non-White Pigment Dispersion Liquid by Resin C> A non-white colorant dispersion liquid (black) was obtained in the same manner except that an acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, acid value: 35) was used as the resin dispersant, carbon black was used as the colorant, and the added amount of the resin dispersant was adjusted so that the mass ratio of the resin dispersant to the pigment was the mass ratio shown in Table 1. The particle size of the pigment was 60 nm in terms of average particle size.

[0241] 3.2. Evaluation Method 3.2.1. Viscosity Increase Ratio The "reactivity with the test liquid (viscosity increase ratio)" described in Table 1 is the ratio of the viscosity of the mixed liquid after mixing to the viscosity of the ink before mixing when each ink and a 7% by mass aqueous calcium formate solution are mixed at a mass ratio of 10:1, stirred for 1 minute, and then the viscosity is measured at 25°C and a shear rate of 200 s -1 under the conditions.

[0242] 3.2.2. Recording Test A modified SC-R5050 inkjet printer (manufactured by Seiko Epson Corporation) was filled with each ink composition and each processing solution. The inkjet heads were arranged so that the inkjet head ejecting the white ink composition and processing solution was on the upstream side in the direction of transport of the recording medium, and the inkjet head ejecting the non-white ink composition and processing solution was on the downstream side. In each example, the same processing solution was used for both the first and second processing solutions.

[0243] The inkjet head that ejects the processing liquid on the upstream side in the transport direction is the inkjet head that performs the first processing liquid adhesion process. It is positioned side-by-side with the inkjet head that ejects the white ink composition, and the white ink composition and the first processing liquid are adhered to it simultaneously. The same procedure was followed for the inkjet head that ejects the non-white ink composition and processing liquid on the downstream side in the transport direction.

[0244] Each test was conducted under the conditions shown in Tables 2-1 to 2-8. For example, in Example 1, the processing liquid and white ink composition were simultaneously applied in one pass, followed by the processing liquid and non-white ink composition. In Example 1, the platen heater was turned off. For the other examples, recordings were also made under the recording conditions shown in Tables 2-1 to 2-8. In Examples 9 and 18, the primary heating process was performed using the platen heater. In Example 16, the number of passes was set to four. In Example 17, the inkjet heads were arranged from upstream to downstream in the recording medium transport direction, in the order of the inkjet head performing the first processing liquid application process, the inkjet head ejecting the white ink composition, the inkjet head performing the second processing liquid application process, and the inkjet head ejecting the non-white ink composition, and the applications were performed in this order.

[0245] The recording resolution was based on 1200 x 1200 dpi, and the number of droplets per pixel was adjusted so that the amount of droplets deposited matched the values ​​in Tables 2-1 to 2-8. Secondary heating was performed by heating the recording medium to 70°C using a secondary heater located downstream in the direction of transport of the recording medium. The recording medium used was PET 50A (Lintec Corporation).

[0246] 3.2.3. Evaluation of filling and pinholes The solid image areas of the recorded material were visually observed under fluorescent lighting and evaluated according to the following criteria. The evaluation of white ink was performed on the portion of the recording pattern where the white ink composition and the first processing solution were applied, but the non-white ink composition and the second processing solution were not. The evaluation of non-white ink was performed on the portion of the recording pattern where the white ink composition and the first processing solution were applied, and then the non-white ink composition and the second processing solution were applied on top of each other. A: There are no unfilled areas or pinholes. B: Some unfilled areas and pinholes are visible. C: Unfilled areas and pinholes are clearly visible.

[0247] 3.2.4. Evaluation of unevenness in shading The solid image areas of the recorded material were visually observed under fluorescent lighting and evaluated according to the following criteria. The recording patterns used for evaluating white ink and non-white ink were the same as those used for evaluating filling and pinholes. A: There is no bleeding (unevenness in color). B: Some bleeding (unevenness in color) is visible. C: Bleeding (unevenness in color intensity) is clearly visible.

[0248] 3.2.5. Evaluation of characters (3pt) (White text) A solid white image was created on top of a solid white image, and white text (3pt) was formed in the areas of the solid white image that did not contain the non-white ink. Then, the bleeding at the boundary between the white and non-white inks was observed. The following evaluation criteria were used. The results are noted in the white areas in the table. A: There is no color bleeding at the border of the white text. B: There is some slight bleeding of color at the border of the white text. C: There is some bleeding between the white text and the colored text at the edges. (non-white characters) Text (3pt) was recorded in non-white ink on a solid white image. The thinness and breakage of the lines of the non-white text were then evaluated. Non-white characters were evaluated according to the following evaluation criteria. The results were recorded in the non-white areas of the table. A: Non-white characters on a white solid background can be clearly read. B: There are some breaks in the non-white characters on a white solid background. C: There are breaks in the non-white characters on a white solid background.

[0249] 3.2.6. Evaluation of Rub Resistance The rub resistance was evaluated as follows using the recorded test pattern. However, the recording medium used was GIY43R5 (transparent polyvinyl chloride manufactured by Lintec Sign Systems). The secondary heating was drying for 10 minutes in an environment of 70°C. The recording patterns used for the evaluation of white ink and the recording patterns used for the evaluation of non-white ink were the same as those for the evaluation of filling and pinholes. A: No peeling occurs when rubbed 10 times with a load of 500 g in the Japan Society for the Promotion of Science rub resistance test. [[ID=J15]] [[ID=J16]]B: Peeling occurs when rubbed 10 times with a load of 500 g in the Japan Society for the Promotion of Science rub resistance test, but the peeling is within 10% of the evaluation area. C: Peeling occurs at more than 10% when rubbed 10 times with a load of 500 g in the Japan Society for the Promotion of Science rub resistance test.

[0250] 3.2.7. Evaluation of Discharge Stability Image recording was continuously performed for 1 hour under the conditions of image formation, and the nozzles of the discharge nozzle group after recording were inspected. The total number of non-discharging nozzles was divided by the total number of nozzles, and the evaluation was carried out according to the following criteria, and the results were described in the table. A: Non-discharging nozzles are within 1.0%. B: Non-discharging nozzles exceed 1.0% and are 2.0% or less. C: Non-discharging nozzles exceed 2.0% and are 5.0% or less.

[0251] [Table 2]

[0252] [Table 3]

[0253] [Table 4]

[0254] [Table 5]

[0255] 3.3. Evaluation Results According to the recording method of each example, when the white ink composition is mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:1, the viscosity increase is 5 times or more, and the amount of processing liquid applied in the second processing liquid application step is smaller than the amount of processing liquid applied in the first processing liquid application step, the image quality of the image formed by the white ink composition can be improved, and the non-white ink composition It was found that this method can suppress bleed unevenness in the resulting image. Furthermore, it was found that it can suppress the thinning of lines in images caused by non-white ink compositions.

[0256] The present invention includes configurations substantially identical to those described in the embodiments, for example, configurations with the same function, method, and results, or configurations with the same purpose and effect. Furthermore, the present invention includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. Furthermore, the present invention includes configurations that produce the same effects or achieve the same purpose as those described in the embodiments. Finally, the present invention includes configurations that add known technology to the configurations described in the embodiments.

[0257] The following can be derived from the embodiments and modifications described above.

[0258] The recording method is: A white ink application step involves applying a white ink composition containing a white colorant to a recording medium, A non-white ink application step involves applying a non-white ink composition containing a non-white colorant to the aforementioned adhering white ink composition, A first processing liquid application step is performed in conjunction with the white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. A second processing liquid application step is performed in conjunction with the non-white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. Equipped with, The aforementioned white ink composition exhibits a viscosity increase of 5 times or more when mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:1. The amount of processing liquid applied in the second processing liquid application step is smaller than the amount of processing liquid applied in the first processing liquid application step.

[0259] According to this recording method, the processing liquid is applied not only in the first processing liquid application step associated with the application of the white ink composition, but also in the second processing liquid application step associated with the application of the non-white ink composition. As a result, the image quality of the image formed by the white ink composition can be improved, and bleed unevenness in the image formed by the non-white ink composition can be suppressed.

[0260] Furthermore, since the amount of processing liquid applied in the second processing liquid application step is smaller than the amount applied in the first processing liquid application step, the amount of processing liquid applied in the second processing liquid application step does not become excessive compared to the amount needed to aggregate the components of the non-white ink composition. As a result, the aggregation of the components of the non-white ink composition does not progress too much, and thus the thinning of image lines caused by the non-white ink composition can be suppressed.

[0261] In the above recording method, The amount of processing liquid applied in the first processing liquid application step is 0.4 mg / inch 2 More than 2.5mg / inch 2 The following is also acceptable.

[0262] This recording method allows for maintaining sufficiently high image quality with white ink compositions while further reducing image bleeding and thinning of fine lines with non-white ink compositions.

[0263] In the above recording method, The amount of processing liquid applied in the second processing liquid application step is 2.5 mg / inch 2 The following is also acceptable.

[0264] According to this recording method, image bleeding and thinning of fine lines caused by non-white ink compositions This can be further reduced.

[0265] In the above recording method, The aforementioned white ink composition may contain a white pigment as a white coloring agent and an anionic dispersant resin.

[0266] This recording method improves the dispersion and aggregation of white pigments, resulting in better dispersion stability and higher image quality.

[0267] In the above recording method, The amount of the white ink composition applied in the white ink application step is 9.0 mg / inch. 2 That's fine too.

[0268] This recording method allows for obtaining even better white images.

[0269] In the above recording method, The white ink application step may be performed in one scan in an area where ink can be applied in one scan, and the non-white ink application step may be performed in one scan in an area where ink can be applied in one scan.

[0270] This recording method allows for recording at a better recording speed.

[0271] In the above recording method, The first processing liquid application step is performed using the same scanning method as the white ink application step. The second processing liquid application step may be performed using the same scanning method as the non-white ink application step.

[0272] This recording method allows for recording at a better recording speed.

[0273] In the above recording method, The total amount of the processing liquid applied in the first processing liquid application step and the processing liquid applied in the second processing liquid application step is 4.0 mg / inch 2 The following is also acceptable.

[0274] This recording method can further suppress the lack of image coverage caused by the white ink composition.

[0275] In the above recording method, The white ink application step, the first processing solution application step, the non-white ink application step, and the second processing solution application step may be performed by an inkjet method.

[0276] In the above recording method, The first processing liquid application step and the second processing liquid application step are performed by an inkjet method. The mass of the multiple droplets of the processing liquid in the first processing liquid application step and the second processing liquid application step may be 7 ng or less.

[0277] This recording method allows for more opportunities for the processing solution and ink to come into contact on the recording medium.

[0278] In the above recording method, The non-white ink composition may exhibit a viscosity increase of 5 times or more when mixed in a mass ratio of non-white ink composition:7% by mass aqueous solution of calcium formate = 10:1.

[0279] This recording method allows for the formation of white images with better image quality.

[0280] In the above recording method, The surface tension of the processing liquid in the first processing liquid application step and the surface tension of the processing liquid in the second processing liquid application step are less than the surface tension of the non-white ink composition. The surface tension of the non-white ink composition may be lower than the surface tension of the white ink composition.

[0281] Furthermore, the surface tension of the processing liquid used in each processing liquid application step may be made lower than the surface tension of the non-white ink composition, and the surface tension of the non-white ink composition may be made lower than the surface tension of the white ink composition. In this way, the processing liquid spreads more easily on the substrate, and the white ink on top of it also spreads more easily, thus improving filling and pinholes. Moreover, since the non-white ink composition spreads more easily than the white ink composition, it is easier to form a non-white image on a white image.

[0282] In the above recording method, The maximum amount of the white ink composition applied in the white ink application step may be greater than the maximum amount of the non-white ink composition applied in the non-white ink application step.

[0283] This recording method allows for recording with better background obscuration.

[0284] In the above recording method, The surface temperature of the recording medium during the application of the white ink composition in the white ink application process is 30°C or lower. The surface temperature of the recording medium during the application of the non-white ink composition in the non-white ink application step may be 30°C or lower.

[0285] This recording method can further enhance the cohesiveness of the white ink composition.

[0286] In the above recording method, The white ink application step does not include a primary heating step, and the non-white ink application step does not need to include a primary heating step.

[0287] This recording method can further improve discharge stability.

[0288] The recording device is The recording method is one of the above, comprising: an adhesion mechanism for performing the white ink adhesion step; an adhesion mechanism for performing the non-white ink adhesion step; an adhesion mechanism for performing the first processing liquid adhesion step; and an adhesion mechanism for performing the second processing liquid adhesion step.

[0289] According to this recording device, the processing liquid is applied not only in the first processing liquid application step associated with the application of the white ink composition, but also in the second processing liquid application step associated with the application of the non-white ink composition. As a result, the image quality of the image formed by the white ink composition can be improved, and bleed unevenness in the image formed by the non-white ink composition can be suppressed.

[0290] Furthermore, the amount of processing liquid applied in the second processing liquid application step is less than the amount of processing liquid applied in the first processing liquid application step. Since the amount of adhesive is smaller than that of the first treatment liquid, the amount of treatment liquid applied in the second treatment liquid application step does not become excessive compared to the amount needed to aggregate the components of the non-white ink composition. Therefore, the aggregation of the components of the non-white ink composition does not progress too much, and thus the thinning of image lines caused by the non-white ink composition can be suppressed. Note that the same adhesion mechanism may be the same mechanism that performs the first treatment liquid application step and the second treatment liquid application step. [Explanation of symbols]

[0291] 1... Inkjet recording device, 2... Inkjet head, 2a, 2b, 2c, 2d... Inkjet head, 3... IR heater, 4... Platen heater, 5... Heating heater, 6... Cooling fan, 7... Preheater, 8... Blower fan, 9... Carriage, 10... Recording medium, 11... Platen, 12... Cartridge, 13... Carriage movement mechanism, 14... Transport means, 101... Interface unit, 102... CPU, 103... Memory, 104... Unit control circuit, 111... Transport unit, 112... Carriage unit, 113... Head unit, 114... Drying unit, 121... Detector group, 130... Computer, CONT... Control unit, MS... Main scanning direction, SS... Sub-scanning direction, M... Recording medium

Claims

1. A white ink application step involves applying a white ink composition containing a white colorant to a recording medium, A non-white ink application step involves applying a non-white ink composition containing a non-white colorant to the aforementioned adhering white ink composition, A first processing liquid application step is performed in conjunction with the white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. A second processing liquid application step is performed in conjunction with the non-white ink application step, in which a processing liquid containing a coagulant is applied to the recording medium. Equipped with, The aforementioned white ink composition exhibits a viscosity increase of 5 times or more when mixed in a mass ratio of white ink composition: 7% by mass aqueous solution of calcium formate = 10:

1. A recording method wherein the amount of processing liquid applied in the second processing liquid application step is less than the amount of processing liquid applied in the first processing liquid application step.

2. In claim 1, The amount of processing liquid applied in the first processing liquid application step is 0.4 mg / inch. ２ 2.5mg / inch or more ２ The recording method is as follows:

3. In claim 1, The amount of processing liquid applied in the second processing liquid application step is 2.5 mg / inch. ２ The recording method is as follows:

4. In claim 1, A recording method comprising the above-mentioned white ink composition containing a white pigment as a white coloring agent and an anionic dispersant resin.

5. In claim 1, The amount of the white ink composition applied in the white ink application step is 9.0 mg / inch. ２ That concludes the recording method.

6. In claim 1, A recording method wherein the white ink application step is performed in one scan on an area where ink can be applied in one scan, and the non-white ink application step is performed in one scan on an area where ink can be applied in one scan.

7. In claim 1, The first processing liquid application step is performed using the same scanning method as the white ink application step. A recording method wherein the second processing liquid application step is performed using the same scanning method as the non-white ink application step.

8. In claim 1, The total amount of the processing liquid applied in the first processing liquid application step and the processing liquid applied in the second processing liquid application step is 4.0 mg / inch. ２ The recording method is as follows:

9. In claim 1, A recording method wherein the white ink application step, the first processing liquid application step, the non-white ink application step, and the second processing liquid application step are performed by an inkjet method.

10. In claim 1, The first processing liquid application step and the second processing liquid application step are performed by an inkjet method. A recording method wherein the mass of multiple droplets of the processing liquid in the first processing liquid application step and the second processing liquid application step is 7 ng or less.

11. In claim 1, The recording method wherein the non-white ink composition exhibits a viscosity increase of 5 times or more when mixed with a 7% by mass aqueous solution of calcium formate in a mass ratio of 10:

1.

12. In claim 1, The surface tension of the processing liquid in the first processing liquid application step and the surface tension of the processing liquid in the second processing liquid application step are less than the surface tension of the non-white ink composition. A recording method wherein the surface tension of the non-white ink composition is less than the surface tension of the white ink composition.

13. In claim 1, A recording method wherein the maximum amount of the white ink composition applied in the white ink application step is greater than the maximum amount of the non-white ink composition applied in the non-white ink application step.

14. In claim 1, The surface temperature of the recording medium during the application of the white ink composition in the white ink application process is 30°C or lower. A recording method wherein the surface temperature of the recording medium during the application of the non-white ink composition in the non-white ink application step is 30°C or lower.

15. In claim 1, A recording method wherein the white ink application step does not include a primary heating step, and the non-white ink application step does not include a primary heating step.

16. The device comprises: an adhesion mechanism for performing the white ink adhesion step; an adhesion mechanism for performing the non-white ink adhesion step; an adhesion mechanism for performing the first processing liquid adhesion step; and an adhesion mechanism for performing the second processing liquid adhesion step. A recording device that performs the recording method described in claim 1.

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