Recording method and recording device

Abstract

To provide a recording method that can reduce contamination in non-image areas (achieve good scratch resistance) while maintaining good productivity. [Solution] A recording method according to one embodiment of the present invention comprises a colored ink application step of ejecting an aqueous colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium, and a clear ink application step of ejecting an aqueous clear ink composition from an inkjet head and adhering it to a recording medium, wherein the colored ink application step and the clear ink application step are performed by scanning, in which ink is ejected from the inkjet head and adhered to the recording medium while moving the relative position of the inkjet head and the recording medium, the colored ink composition is adhered to the image portion of a scanning area of ​​the recording medium, the clear ink composition is adhered to the non-image portion of a scanning area in the same scan as said scan, and the clear ink composition is adhered to the image portion and non-image portion of a scanning area in a scan after said scan, and the total amount of the clear ink composition adhered to the non-image portion is 3 mg / inch 2 The clear ink composition contains wax and a fixing resin, wherein the wax content is 0.7% by mass or more of the total mass of the clear ink composition, and the combined content of wax and fixing resin is 4.5% by mass or more of the total mass of the clear ink composition.

Description

[Technical Field]

[0001] This invention relates to a recording method and a recording apparatus. [Background technology]

[0002] Inkjet recording methods, which allow for the recording of high-resolution images with relatively simple equipment, are undergoing rapid development in various fields. Within this context, the use of clear ink containing fixing resins in combination with inkjet recordings is being investigated to improve the abrasion resistance of the recorded material.

[0003] For example, Patent Document 1 discloses an inkjet recording method in which a clear ink composition containing resin particles is overcoated onto a color ink. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-144764 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, there is a challenge in reducing contamination in the non-image areas of the recording material (achieving good scratch resistance) without increasing the time required for recording (maintaining good productivity). [Means for solving the problem]

[0006] One aspect of the recording method according to the present invention is: A colored ink application process involves ejecting a water-based colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium. The system includes a clear ink application step in which a water-based clear ink composition is ejected from an inkjet head and adhered to a recording medium, The color ink adhesion step and the clear ink adhesion step are performed by scanning in which the inkjet head discharges ink from the inkjet head while moving the relative position of the inkjet head and the recording medium, and adheres it to the recording medium. The color ink composition is adhered to the image portion of a scanning area of the recording medium. In the same scan as the scan, the clear ink composition is adhered to the non-image portion of the certain scan area. In a scan after the scan, the clear ink composition is adhered to the image portion and the non-image portion of the certain scan area. The total adhesion amount of the clear ink composition in the non-image portion is 3 mg / inch 2 or more. The clear ink composition contains wax and a fixing resin. The content of the wax is 0.7% by mass or more based on the total mass of the clear ink composition. The total content of the wax and the fixing resin is 4.5% by mass or more based on the total mass of the clear ink composition.

[0007] One aspect of the recording apparatus according to the present invention is A recording apparatus that performs the recording method of the above aspect, It has the color ink composition, the clear ink composition, and an inkjet head that discharges the color ink composition and the clear ink composition.

Brief Description of the Drawings

[0008] [Figure 1] A schematic cross-sectional view schematically showing an inkjet recording apparatus. [Figure 2] A perspective view showing an example of the configuration around the carriage of the inkjet recording apparatus. [Figure 3] A schematic view showing an example of the arrangement of the inkjet heads. [Figure 4] A schematic view showing an example of the arrangement of the inkjet heads. [Figure 5] Table 1 showing composition examples of the color ink composition and the clear ink composition. [Figure 6] Table 2 shows the printing conditions and evaluation results for each example. [Figure 7] Table 3 shows the printing conditions and evaluation results for each example and comparative example. [Modes for carrying out the invention]

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

[0010] In this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0011] 1. Recording Method A recording method according to one embodiment of the present invention comprises a colored ink application step of ejecting an aqueous colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium, and a clear ink application step of ejecting an aqueous clear ink composition from an inkjet head and adhering it to a recording medium, wherein the colored ink application step and the clear ink application step are performed by scanning, in which ink is ejected from the inkjet head and adhered to the recording medium while moving the relative position of the inkjet head and the recording medium, the colored ink composition is adhered to the image portion of a certain scanning area of ​​the recording medium, the clear ink composition is adhered to the non-image portion of a certain scanning area in the same scan, and the clear ink composition is adhered to the image portion and the non-image portion of a certain scanning area in a scan after the scan, and the total amount of the clear ink composition adhered to the non-image portion is 3 mg / inch 2The clear ink composition contains wax and a fixing resin, the wax content being 0.7% by mass or more of the total mass of the clear ink composition, and the combined content of the wax and the fixing resin being 4.5% by mass or more of the total mass of the clear ink composition.

[0012] In inkjet-recorded materials, there is a problem where non-image areas become soiled when the material is rubbed. That is, when the recording surfaces are rubbed together during handling of the material, for example, during printing or during the transportation of items to which the material is attached, the ink from the image area peels off and transfers to the non-image area, causing a problem where the peeled ink hardens and becomes soiled on the non-image area. In response to this problem, it is conceivable to overcoat the image area with a clear ink composition (hereinafter also referred to as "clear ink") to prevent the ink from peeling off, but if even a small amount of ink from the image area peels off, it is unavoidable that the ink will harden on the non-image area.

[0013] Therefore, we found that by applying clear ink to the non-image areas as well, the adhesion of peeled-off ink to these areas can be reduced, thereby reducing dirt on the non-image areas. Because clear ink is applied to the non-image areas, the surface of these areas is smoothed, reducing friction when the recorded material is rubbed, making it less likely for the ink to peel off, and even if peeled-off ink does adhere, it is less likely to harden. However, to achieve this effect, it is necessary to apply a certain amount or more of clear ink to the non-image areas. However, with inkjet ink application, there is a limit to the amount of ink that can be applied at once (the amount applied in one scan). Therefore, applying a certain amount or more of clear ink to the non-image areas cannot be done in one go and must be done in multiple steps. However, for good productivity, the time required for recording must not be too long.

[0014] Therefore, in the recording method according to this embodiment, it was found that the adhesion of clear ink to the non-image area is divided into two timings: one at the same time as the adhesion of the colored ink composition (hereinafter also referred to as "colored ink") and another at a subsequent timing. This makes it possible to reduce contamination in the non-image area (achieve good scratch resistance) while maintaining good productivity.

[0015] The following describes each step of the recording method according to this embodiment.

[0016] 1.1 Colored ink application process and clear ink application process The recording method according to this embodiment includes a colored ink application step of ejecting an aqueous colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium, and a clear ink application step of ejecting an aqueous clear ink composition from an inkjet head and adhering it to a recording medium.

[0017] 1.1.1 Adhesion Pattern In the recording method according to this embodiment, the colored ink adhesion step and the clear ink adhesion step are performed by scanning, in which ink is ejected from the inkjet head and adhered to the recording medium while moving the relative position of the inkjet head and the recording medium. The colored ink composition is adhered to the image portion of a scanning area of ​​the recording medium, the clear ink composition is adhered to the non-image portion of a scanning area in the same scan, and the clear ink composition is adhered to the image portion and non-image portion of a scanning area in a scan after the first scan, with the total amount of clear ink composition adhered to the non-image portion being 3 mg / inch. 2 That's all.

[0018] In this embodiment, the recording method involves applying clear ink to non-image areas in two separate steps: simultaneously with the application of colored ink and at a subsequent timing. Specifically, first, a scan is performed to apply clear ink to non-image areas using the same scan as the application of colored ink to image areas (clear ink application 1), and then a scan is performed to apply clear ink to both image and non-image areas (clear ink application 2). By performing the application of clear ink to non-image areas in two separate steps, the amount of clear ink applied to non-image areas can be increased to a predetermined amount or more.

[0019] Since the clear ink application 1 is performed simultaneously with the scanning that applies colored ink to the image area, even if the amount of clear ink applied to the non-image area exceeds a predetermined amount, it is not necessary to increase the number of scans in the recording process, thus maintaining good productivity.

[0020] Furthermore, in order to obtain good scratch resistance, it is necessary to apply clear ink to the image area as well. However, if the colored ink and clear ink are mixed before they are completely dry, the image quality may deteriorate. Therefore, by applying clear ink to the image area in a scan that follows the scan that applies colored ink to the image area, the clear ink is applied after the colored ink has dried, thus suppressing a decrease in image quality. It is reasonable to perform this scan that applies clear ink to the image area simultaneously with the clear ink application 2.

[0021] 1.1.1.1 Scanning In the recording method according to this embodiment, the colored ink application step and the clear ink application step, described later, are performed by scanning, in which ink is ejected from the inkjet head and applied to the recording medium while the relative position of the inkjet head and the recording medium are moved.

[0022] "Moving the relative position of the inkjet head and the recording medium" means moving the inkjet head relative to the recording medium. In this case, the inkjet head may move relative to the recording medium, or the recording medium may move relative to the inkjet head. Furthermore, the relative positional relationship between the inkjet head and the recording medium may change as both move. The inkjet head can be mounted on a carriage, for example. The inkjet head may be moved as the carriage moves; in this case as well, it is the movement of the inkjet head.

[0023] For example, "scanning, which involves moving the relative position of the inkjet head and the recording medium while ejecting ink from the inkjet head and adhering it to the recording medium," refers to a serial inkjet recording device 1 as shown in Figure 2, in which recording is performed while the carriage 9 having the inkjet head 2 moves in a scanning direction (MS direction) that intersects with the transport direction (T2 direction) of the recording medium M. This operation is also called "main scanning."

[0024] The direction in which the inkjet head moves relative to the recording medium is also called the "main scanning direction." The direction intersecting the main scanning direction is also called the "sub-scanning direction," and the operation of moving the relative position of the inkjet head and the recording medium in the sub-scanning direction is called "sub-scanning." For example, by applying ink to a scanning area of ​​the recording medium during a main scan, slightly moving the recording medium during a sub-scan, and then performing the next main scan, it is possible to record by repeatedly applying ink adjacent to or partially overlapping the previously applied ink. Note that "sub-scan" is also a movement of the relative position between the inkjet head and the recording medium; the inkjet head may move relative to the recording medium, or the recording medium may move relative to the inkjet head. The direction of such relative movement is called the sub-scan direction.

[0025] It is preferable to perform recording by performing both the main scan and the sub-scan multiple times. For example, the main scan and sub-scan can be performed alternately and repeatedly.

[0026] 1.1.1.2 Adhesion of colored ink In the recording method according to this embodiment, the colored ink composition is applied to the image portion of a scanning area on a recording medium by the scanning described above.

[0027] The "image area" refers to the region on the recording medium where an image (visible characters, figures, patterns, etc., formed by ink, etc.) is intended to be formed. The image area may include areas where no colored ink composition is applied. "Non-image area" refers to the region that is not part of the image.

[0028] The amount of colored ink composition applied is preferably 2.0 to 20 mg / inch per unit area of ​​the image. 2 More preferably, 3.0 to 10 mg / inch 2 And more preferably 6.0 to 8.0 mg / inch 2 Furthermore, it is preferable that the recording medium includes the region of the above-mentioned adhesion amount range, and that the maximum adhesion amount range of the colored ink composition in the recording is less than or equal to the above-mentioned adhesion amount range.

[0029] 1.1.1.3 Clear ink adhesion 1 The recording method according to this embodiment involves attaching a clear ink composition to a non-image area of ​​a certain scanning region during the same scan as the scan in question (clear ink attachment 1). That is, the clear ink composition is attached to a non-image area of ​​a certain scanning region during the same scan as the scan in which the colored ink composition is attached to the image area of ​​a certain scanning region of the recording medium.

[0030] The amount of clear ink composition applied in clear ink adhesion 1 is preferably 1.0 to 3.0 mg / inch per unit area in the non-image area. 2 More preferably 1.5 to 2.5 mg / inch 2 And more preferably 1.7 to 2.2 mg / inch2 It is also preferable that the recording medium includes the region within the above adhesion amount range, and it is also preferable that the maximum adhesion amount range of the clear ink composition in recording is not more than the above adhesion amount range.

[0031] The region where the clear ink composition is adhered in the non-image area preferably includes a range extending from 2 cm or more to the end around the image area, more preferably includes a range extending from 3 cm or more to the end around the image area, and even more preferably includes a range extending from 5 cm or more to the end around the image area. That is, when focusing on a certain image area in the recording area where recording is performed in the recording method, it is preferable that the region where the clear ink composition is adhered is included in a range extending from a predetermined length or more to the end around the image area. Also, the region where the clear ink composition is adhered in the non-image area is particularly preferably the entire non-image area, but good abrasion resistance can also be obtained even if it is not the entire non-image area.

[0032] In the recording method according to the present embodiment, the clear ink composition may be adhered to the image area of a certain scanning area by the same scanning as the scanning for adhering the colored ink composition to the image area of the recording medium. However, since the image quality may deteriorate when the non-sufficiently dried colored ink and clear ink are mixed, it is preferable that the adhesion amount in this case is small. The adhesion amount of the clear ink composition to the image area of a certain scanning area by the same scanning is preferably 2.0 mg / inch 2 or less, more preferably 1.5 mg / inch 2 or less, even more preferably 1.0 mg / inch 2 or less, particularly preferably 0.5 mg / inch 2 or less, and it is more particularly preferable that no adhesion occurs (0 mg / inch 2 ).

[0033] In clear ink application 1, the scanning process for applying the clear ink composition may be performed multiple times over a given scanning area. In this case, the inkjet head performing the scanning to apply the clear ink composition will pass over the scanning area multiple times. The number of times the inkjet head passes over an arbitrary area when recording that area is called the "number of passes". From the viewpoint of maintaining productivity, the number of scans described above is preferably 6 times or less, more preferably 5 times or less, and even more preferably 4 times or less.

[0034] 1.1.1.4 Clear ink adhesion 2 In the recording method according to this embodiment, a clear ink composition is applied to the image and non-image areas of a certain scanning region during a scan that occurs after the initial scan (clear ink application 2). That is, the clear ink composition is applied to the image and non-image areas of a certain scanning region during a scan that occurs after the scan in which the colored ink composition is applied to the image areas of a certain scanning region of the recording medium.

[0035] In clear ink adhesion 2, the amount of clear ink composition adhered is preferably 1.0 to 3.0 mg / inch per unit area in the non-image area. 2 More preferably 1.5 to 2.5 mg / inch 2 And more preferably 1.7 to 2.2 mg / inch 2 It is also preferable that the recording medium includes the region of the above-mentioned adhesion amount range, and that the maximum adhesion amount range of the clear ink composition in recording is less than or equal to the above-mentioned adhesion amount range.

[0036] From the viewpoint of superior image quality, it is preferable that the amount of clear ink composition (C2) applied in clear ink application 2 is greater than the amount of clear ink composition applied in clear ink application 1 (C1). The ratio of the amounts applied to the two (C2 / C1) is preferably 1 / 3 or more, more preferably 1 / 1 or more, even more preferably greater than 1 / 1, particularly preferably 2 / 1 or more, and most particularly preferably 3 / 1 or more.

[0037] The amount of clear ink composition applied in clear ink application 2 can be the same as described above in the image area.

[0038] In the recording method according to this embodiment, the total amount of clear ink composition attached to the non-image area, i.e., the total amount of clear ink composition attached to the non-image area by clear ink attachment 1 and clear ink attachment 2, is 3 mg / inch. 2 That concludes the report. The total amount of adhesion is 3 mg / inch. 2 As a result, the adhesion of peeled-off ink to non-image areas is reduced, and staining of non-image areas can be reduced. The total amount of adhesion is 3 mg / inch 2 That concludes the explanation, but the dosage is 3.3 mg / inch. 2 The above is preferable, 3.5 mg / inch 2 The above is more preferable, 3.7 mg / inch 2 The above is even more preferable, 4.0 mg / inch 2 The above is particularly preferable. Furthermore, the total amount of adhesion is 5.0 mg / inch. 2 It may be greater than or equal to 6.0 mg / inch 2 That's fine too. The upper limit of the total amount of adhesion is not particularly limited, but is 10.0 mg / inch. 2 The following is preferred: 8.0 mg / inch 2 The following is more preferable: 6.0 mg / inch 2 The following is even more preferable: 5.0 mg / inch 2 The following are particularly preferable.

[0039] In the clear ink application 2, the scanning process for applying the clear ink composition may be performed multiple times on a given scanning area. From the viewpoint of maintaining productivity, the number of scans described above is preferably four or fewer, more preferably three or fewer, and even more preferably two or fewer.

[0040] From the viewpoint of maintaining productivity, the total number of scans for clear ink application 1 and clear ink application 2 is preferably 7 times or less, more preferably 6 times or less, even more preferably 5 times or less, and particularly preferably 4 times or less.

[0041] 1.1.2 Clear Ink Composition The aqueous clear ink composition used in the clear ink application step of the recording method according to this embodiment contains wax and a fixing resin. The components contained in the clear ink composition will be described below.

[0042] 1.1.2.1 Wax The clear ink composition contains wax. The inclusion of wax reduces friction when the recorded material is rubbed, making the ink less likely to peel off, and also makes it less likely for peeled-off ink to adhere if it does come into contact with something.

[0043] The properties of waxes include those that dissolve in ink, or those that are dispersed in the form of fine particles, such as emulsions. Using waxes of these properties tends to result in recordings with superior abrasion resistance.

[0044] Examples of waxes include hydrocarbon waxes and ester waxes, which are condensates of fatty acids with monohydric or polyhydric alcohols. Examples of hydrocarbon waxes are not particularly limited, but include paraffin wax and polyolefin waxes such as polyethylene wax and polypropylene wax. Among these, from the viewpoint of having superior discharge stability, it is preferable that the wax contains polyolefin wax.

[0045] Examples of commercially available paraffin waxes include AQUACER497 and AQUACER539 (product names, manufactured by BYK).

[0046] Examples of commercially available polyolefin waxes include Chemipearl S120, S650, S75N (product names, manufactured by Mitsui Chemicals, Inc.), AQUACER501, AQUACER506, AQUACER513, AQUACER515 (polyethylene wax), AQUACER526, AQUACER531 (polyethylene wax), AQUACER593, and AQUACER582 (product names, manufactured by BYK).

[0047] The volume-average particle size (D50) of the wax contained in the clear ink composition is preferably 40 nm or more, more preferably 50 nm or more, even more preferably 70 nm or more, particularly preferably 100 nm or more, and most particularly preferably 130 nm or more. In particular, when the volume-average particle size (D50) of the wax is 50 nm or more, the abrasion resistance tends to be superior. Furthermore, the upper limit of the volume-average particle size (D50) of the wax contained in the clear ink composition is arbitrary within the range applicable to the inkjet method, but is, for example, 200 nm or less, preferably 150 nm or less.

[0048] From the viewpoint of obtaining good abrasion resistance, the wax content is 0.7% by mass or more relative to the total mass of the clear ink composition. The wax content is 0.7% by mass or more relative to the total mass of the clear ink composition, but 0.9% by mass or more is preferred, and 1.0% by mass or more is more preferred. From the viewpoint of ensuring good discharge stability, the upper limit of the wax content is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less, relative to the total mass of the clear ink composition.

[0049] The total content of wax and the fixing resin described later is 4.5% by mass or more relative to the total mass of the clear ink composition, from the viewpoint of obtaining good abrasion resistance. The total content of wax and fixing resin is 4.5% by mass or more relative to the total mass of the clear ink composition, but 5.0% by mass or more is preferred, and 7.0% by mass or more is more preferred. Furthermore, from the viewpoint of ensuring good discharge stability, the upper limit of the total content of wax and fixing resin is preferably 15.0% by mass or less, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less, relative to the total mass of the clear ink composition.

[0050] In a clear ink composition, from the viewpoint of balancing abrasion resistance and discharge stability, it is preferable that the total content of wax and fixing resin is 5.0% by mass or more and 10.0% by mass or less relative to the total mass of the clear ink composition, and that the wax content is 1.0% by mass or more and 3.0% by mass or less relative to the total mass of the clear ink composition.

[0051] 1.1.2.2 Fixing resin The clear ink composition contains a fixing resin. The fixing resin has functions such as improving the adhesion and abrasion resistance of the ink components, and smoothing the surface of the recording medium or the ink coating.

[0052] The fixing resin may be a water-soluble resin, but it is preferably in the form of resin particles. The resin particles are often handled in emulsion form, but they may also be in powder form. The fixing resin can be dispersed or dissolved in the solvent component of the ink and included in the ink.

[0053] Examples of fixing resins 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, and ethylene vinyl acetate resins. Among these, urethane resins, acrylic resins, polyolefin resins, and polyester resins are preferred.

[0054] 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.).

[0055] 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.

[0056] 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 6969D, 6899D, 952B, 718A (trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Nipol LX852, LX874 (trade name, manufactured by Nippon Zeon Co., Ltd.), etc.

[0057] In this specification, the acrylic resin may be a styrene-acrylic resin as described later.

[0058] 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.

[0059] 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.).

[0060] Furthermore, the fixing resin 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.

[0061] From the viewpoint of achieving superior abrasion resistance, the content of the fixing resin in the clear ink composition is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, even more preferably 5.0% by mass or more, and particularly preferably 6.0% by mass or more, based on the total mass of the clear ink composition. Furthermore, from the viewpoint of achieving superior discharge stability, the content of the fixing resin in the clear ink composition is preferably 15.0% by mass or less, more preferably 10% by mass or less, even more preferably 8.0% by mass or less, even more preferably 7.0% by mass or less, and particularly preferably 6.5% by mass or less, relative to the total mass of the clear ink composition.

[0062] 1.1.2.3 Water Clear ink compositions are water-based compositions. "Water-based" means that they contain at least water as a solvent component, and may contain water as the main solvent component.

[0063] Examples of suitable water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water, which has reduced ionic impurities. Furthermore, using water sterilized by ultraviolet irradiation or the addition of hydrogen peroxide can suppress the growth of bacteria and fungi when the clear ink composition is stored for a long period of time.

[0064] The water content is preferably 50% by mass or more, more preferably 50 to 100% by mass, in the liquid medium component. Furthermore, it is preferably 70 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 95 to 99% by mass. The liquid medium refers to a solvent component such as water or an organic solvent. Furthermore, the water content is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to the total mass of the clear ink composition. There is no particular upper limit to the water content, but for example, it is preferably 99% by mass or less, more preferably 90% by mass or less, and even more preferably 70% by mass or less, relative to the total mass of the clear ink composition.

[0065] 1.1.2.4 Organic Solvents The clear ink composition may contain an organic solvent. Preferably, the organic solvent is a water-soluble organic solvent. "Water-soluble" means that its solubility in water at 20°C is greater than 10g / 100g of water.

[0066] Examples of organic solvents include esters, cyclic esters, amides, alcohols, and polyhydric alcohols. Note that glycol ether solvents, which will be discussed later, are not included in the category of organic solvents.

[0067] Esters include glycol monoacetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, methoxybutyl acetate, ethylene glycol diacetate, and diethylene glycol. Examples of glycol diesters include propyl diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, diethylene glycol acetate butyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate, dipropylene glycol acetate butyrate, and dipropylene glycol acetate propionate.

[0068] Examples of cyclic esters include cyclic esters (lactones) such as β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, β-butyrolactone, β-valerolactone, γ-valerolactone, β-hexanolactone, γ-hexanolactone, δ-hexanolactone, β-heptanolactone, γ-heptanolactone, δ-heptanolactone, ε-heptanolactone, γ-octanolactone, δ-octanolactone, ε-octanolactone, δ-nonalactone, ε-nonalactone, and ε-decanolactone, 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.

[0069] Examples of amides include cyclic amides and acyclic amides. Examples of acyclic amides include alkoxyalkyl amides.

[0070] Examples of cyclic amides include lactams. Examples of lactams include pyrrolidones such as 2-pyrrolidone, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-propyl-2-pyrrolidone, 1-butyl-2-pyrrolidone, and 1-(2-hydroxyethyl)pyrrolidine-2-one.

[0071] 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, 3-n-butoxy-N,N-methylethylpropionamide, and 3-n-propoxy-N,N-dimethylpropionamide. Examples include propionamide, 3-n-propoxy-N,N-diethylpropionamide, 3-n-propoxy-N,N-methylethylpropionamide, 3-iso-propoxy-N,N-dimethylpropionamide, 3-iso-propoxy-N,N-diethylpropionamide, 3-iso-propoxy-N,N-methylethylpropionamide, 3-tert-butoxy-N,N-dimethylpropionamide, 3-tert-butoxy-N,N-diethylpropionamide, 3-tert-butoxy-N,N-methylethylpropionamide, N,N-dimethylisobutyrateamide, etc.

[0072] Examples of alcohols include compounds in which one hydrogen atom of an alkane is replaced by a hydroxyl group. The alkane preferably has 10 or fewer carbon atoms, more preferably 6 or fewer, and even more preferably 3 or fewer. The alkane has 1 or more carbon atoms, preferably 2 or more. The alkane may be linear or branched. Examples of alcohols include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, 2-phenoxyethanol, benzyl alcohol, and phenoxypropanol.

[0073] Polyhydric alcohols are molecules that contain two or more hydroxyl groups. Polyhydric alcohols can be further classified into, for example, alkanediols and polyols.

[0074] Alkanediols include, for example, compounds in which an alkane is substituted with two hydroxyl groups. Examples of alkanediols include 1,2-alkanediols, which are a general term for compounds in which hydroxyl groups are substituted at the 1st and 2nd positions of an alkane, and other alkanediols other than 1,2-alkanediols.

[0075] Examples of 1,2-alkanediols include ethylene glycol, 1,2-propanediol (propylene glycol), 1,2-butanediol, 1,2-pentanediol (1,2PD), 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, 1,2-nonanediol, 1,2-decanediol, 3-methyl-1,2-butanediol, 3-methyl-1,2-pentanediol, 4-methyl-1,2-pentanediol, 3,4-dimethyl-1,2-pentanediol, and 3 Examples include -ethyl-1,2-pentanediol, 4-ethyl-1,2-pentanediol, 3-methyl-1,2-hexanediol, 4-methyl-1,2-hexanediol, 5-methyl-1,2-hexanediol, 3,4-dimethyl-1,2-hexanediol, 3,5-dimethyl-1,2-hexanediol, 4,5-dimethyl-1,2-hexanediol, 3-ethyl-1,2-hexanediol, 4-ethyl-1,2-hexanediol, and 3-ethyl-4-methyl-1,2-hexanediol.

[0076] Other examples of alkanediols include 1,3-propanediol, 1,3-butylene glycol (also known as 1,3-butanediol), 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, 2-methylpentane-2,4-diol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, and 2-methyl-2-propyl-1,3-propanediol.

[0077] Examples of polyols include condensates formed by the intermolecular condensation of two or more alkanediol molecules via hydroxyl groups, and compounds having three or more hydroxyl groups.

[0078] Examples of condensates formed by the intermolecular condensation of two or more alkanediol molecules at their hydroxyl groups include dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylene glycols such as triethylene glycol and tripropylene glycol.

[0079] Compounds having three or more hydroxyl groups are compounds with an alkane or polyether structure as their backbone and containing three or more hydroxyl groups. Examples of compounds having three or more hydroxyl groups include glycerin, trimethylolethane, trimethylolpropane, 1,2,5-hexanetriol, 1,2,6-hexanetriol, pentaerythritol, and polyoxypropylenetriol.

[0080] Organic solvents may be used individually or in combination of two or more types.

[0081] The clear ink composition preferably contains alkanediols, and more preferably contains alkanediols in which hydroxyl groups are substituted at both ends of a molecule with 5 or fewer carbon atoms. When alkanediols with hydroxyl groups substituted at both ends of a molecule with 5 or fewer carbon atoms are included, the discharge stability tends to be superior. Examples of alkanediols with hydroxyl groups substituted at both ends of a molecule with 5 or fewer carbon atoms include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0082] The clear ink composition preferably contains an organic solvent with a standard boiling point of 250°C or lower, more preferably an organic solvent with a standard boiling point of 230°C or lower, even more preferably an organic solvent with a standard boiling point of 210°C or lower, and particularly preferably an organic solvent with a standard boiling point of less than 200°C. It is also preferable to set the maximum standard boiling point range of the organic solvent contained in the clear ink composition to 250°C or less, which tends to result in superior scratch resistance and image quality.

[0083] In a clear ink composition, the content of organic solvents with a standard boiling point below 200°C is preferably 50% by mass or more of the total content of organic solvents, from the viewpoint of achieving superior scratch resistance and image quality. Furthermore, there is no particular upper limit to the content of organic solvents with a standard boiling point below 200°C, but it is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, relative to the total content of organic solvents.

[0084] From the viewpoint of obtaining better abrasion resistance, the clear ink composition preferably contains no polyols with a standard boiling point of 280°C or higher in an amount of 0.5% by mass or more, more preferably 0.3% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably no polyols (0% by mass) in the total mass of the clear ink composition.

[0085] The content of the organic solvent in the clear ink composition is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and even more preferably 15 to 23% by mass, based on the total mass of the clear ink composition.

[0086] 1.1.2.5 Glycol ether-based solvents The clear ink composition may contain a glycol ether solvent. Examples of glycol ether solvents include alkylene glycol monoethers or diethers.

[0087] Examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether. Examples include alkylene glycol monoalkyl ethers such as tripropylene glycol monobutyl ether; and alkylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol methyl butyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, and tripropylene glycol dimethyl ether.

[0088] The clear ink composition preferably contains no glycol ether solvent in an amount of 2.0% by mass or more, more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably no solvent (0% by mass) relative to the total mass of the clear ink composition. Glycol ether-based solvents have high resin solubility, which causes the fixing resin to dissolve and fuse within the inkjet head, resulting in poor ejection stability (redispersibility). Therefore, it is preferable that the content of glycol ether-based solvent in the clear ink composition be within the above range.

[0089] 1.1.2.6 Surfactants The clear ink composition may contain a surfactant. Any of the following surfactants can be used: nonionic surfactants, anionic surfactants, cationic surfactants, or amphoteric surfactants, and these may be used in combination. Among surfactants, acetylene glycol-based surfactants, silicone-based surfactants, and fluorine-based surfactants are more preferably used, with silicone-based surfactants being even more preferably used.

[0090] 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 brand names, manufactured by Air Products Japan Co., Ltd.), O Examples include Rufin 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 brand names, manufactured by Nisshin Chemical Industry Co., Ltd.), and Acetyleneol E00, E00P, E40, E100 (all brand names, manufactured by Kawaken Fine Chemical Co., Ltd.).

[0091] While not particularly limited, polysiloxane compounds are preferred as silicone-based surfactants. Examples of such 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 product names, manufactured by Bic Chemie Japan Co., Ltd.), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-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 SAG503A, Silface SAG014 (both product names, manufactured by Nisshin Chemical Industry Co., Ltd.).

[0092] As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and a specific example is BYK-340 (trade name, manufactured by BYK-Chemie Japan Co., Ltd.).

[0093] The above-mentioned surfactants may be used individually or in combination of two or more. Furthermore, some of the exemplified surfactants that function as defoaming agents may also be used. An example of such a defoaming agent is Surfinol DF110D (trade name, manufactured by Air Products Japan Co., Ltd.).

[0094] The clear ink composition preferably contains a surfactant with an HLB value of 10 or higher.

[0095] In this specification, the "HLB value" (value of hydrophile and liophile balance) is a numerical representation of the hydrophilic-hydrophobic balance of a compound. Here, the HLB value is calculated using the Griffin method and can be determined by the following formula (1). HLB value = 20 × sum of formula weights of hydrophilic parts / molecular weight ... (1)

[0096] The surfactant content is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, particularly preferably 1.5% by mass or less, and most particularly preferably 1.0% by mass or less, based on the total mass of the clear ink composition. The lower limit of the surfactant content is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and more preferably 0.5% by mass or more, based on the total mass of the clear ink composition.

[0097] 1.1.2.7 Other ingredients The clear ink composition may optionally contain additives such as pH adjusters, preservatives / fungal agents, rust inhibitors, chelating agents, viscosity modifiers, solubilizers, and antioxidants. When such additives are included, the content is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.1 to 1% by mass, relative to the total amount of the clear ink composition.

[0098] Furthermore, the clear ink composition may contain a colorant, but it is preferably 0.2% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, and the lower limit is 0% by mass, relative to the total amount of the clear ink composition. It is preferable that the clear ink composition does not contain a colorant.

[0099] 1.1.2.8 Physical Properties From the viewpoint of balancing image quality and reliability as an ink for inkjet recording, the clear ink composition preferably has a surface tension (static surface tension) of 18 mN / m to 40 mN / m at 20°C, more preferably 20 mN / m to 35 mN / m, and even more preferably 22 mN / m to 33 mN / m. The surface tension can be measured, for example, by using an automatic surface tension meter CBVP-Z (product name, manufactured by Kyowa Interface Science Co., Ltd.) to check the surface tension when a platinum plate is wetted with the ink in an environment of 20°C.

[0100] The viscosity of the clear ink composition at 20°C is preferably 3 mPa·s to 10 mPa·s, and more preferably 3 mPa·s to 8 mPa·s. Viscosity can be measured, for example, using a viscoelasticity tester MCR-300 (product name, manufactured by Pysica) to measure the viscosity at 20°C.

[0101] 1.1.3 Colored Ink Composition The aqueous colored ink composition used in the colored ink application step of the recording method according to this embodiment contains a colorant. The components contained in the colored ink composition are described below. In the following description, components common to the clear ink composition described above may have the same configuration as the clear ink composition unless otherwise specified.

[0102] 1.1.3.1 Colorants The colored ink composition contains a colorant. Examples of colorants include pigments and dyes. Examples of pigments include inorganic pigments and organic pigments.

[0103] Inorganic pigments are not particularly limited, but examples include carbon blacks such as CI Pigment Black 6 (Lamp Black, Vegetable Black), CI Pigment Black 7 (Furnace Black, Channel Black, Thermal Black, Acetylene Black), CI Pigment Black 8 (Charcoal Black), and CI Pigment Black 10 (Graphite); and white pigments such as iron oxide, titanium oxide, zinc oxide, and silica.

[0104] Examples of carbon black include Mitsubishi Chemical Corporation's No. 2300, 900, MCF88, No. 20B, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, and No. 2200B. Examples of Degussa's Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pritex 35, U, V, 140U, and Special Black 6, 5, 4A, 4, and 250. Examples of Columbia Carbon's Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, and 700. Examples include Cabot's Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, and Elftex 12.

[0105] Examples of white pigments include CI Pigment White 1, which is basic lead carbonate; CI Pigment White 4, which is zinc oxide; CI Pigment White 5, which is a mixture of zinc sulfide and barium sulfate; CI Pigment White 6, which is titanium dioxide; CI Pigment White 6:1, which is titanium dioxide containing other metal oxides; CI Pigment White 7, which is zinc sulfide; CI Pigment White 18, which is calcium carbonate; CI Pigment White 19, which is clay; CI Pigment White 20, which is titanium mica; CI Pigment White 21, which is barium sulfate; CI Pigment White 22, which is gypsum; CI Pigment White 26, which is magnesium oxide and silicon dioxide; CI Pigment White 27, which is silicon dioxide; and CI Pigment White 28, which is anhydrous calcium silicate. Among these, it is preferable to use CI Pigment White 6, which has excellent color development and opacity.

[0106] Examples of organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ancenthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimimidazolone pigments, isoindolinone pigments, azomethine pigments, or azo pigments.

[0107] Specific examples of organic pigments include the following:

[0108] Examples of cyan pigments include CI Pigment Blue 1, 2, 3, 15:3, 15:4, 15:34, 16, 22, 60, etc.; CI Bat Blue 4, 60, etc. Preferably, one or more mixtures selected from the group consisting of CI Pigment Blue 15:3, 15:4, and 60 can be exemplified.

[0109] Examples of magenta pigments include CI Pigment Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122, 123, 168, 184, 202, and CI Pigment Violet 19. Preferably, one or more mixtures selected from the group consisting of CI Pigment Red 122, 202, and 209, and CI Pigment Violet 19 can be exemplified.

[0110] Examples of yellow pigments include CI Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc. Preferably, one or more mixtures selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, 138, 150, and 180 can be exemplified.

[0111] Other colored pigments can also be used. For example, orange pigment and green pigment can be used.

[0112] Pigments may be used individually or in combination of two or more types.

[0113] The volume-average particle size (D50) of the pigment, as measured by dynamic light scattering, is 20 nm to 300 nm, more preferably 30 nm to 200 nm, and even more preferably 40 nm to 100 nm.

[0114] The volume-average particle size can be measured, for example, using a NanoTrac series particle distribution analyzer manufactured by MicroTracBel. Methods for adjusting the volume-average particle size include, for example, adjusting the degree of grinding of the pigment before dispersion, adjusting the stirring conditions during dispersion (e.g., stirring speed, stirring temperature, etc.), and adjusting by filtration using a filter after dispersion.

[0115] To improve the dispersibility of pigments in the ink composition, it is preferable to either surface-treat the colorant or incorporate a dispersant.

[0116] The surface treatment of the pigment is preferably a process that directly or indirectly bonds functional groups such as carbonyl groups, carboxyl groups, aldehyde groups, hydroxyl groups, sulfone groups, ammonium groups, and salts thereof to the surface of the colorant by physical or chemical treatment. In particular, the surface treatment is more preferably a process that modifies the surface of the colorant by oxidizing or sulfonating the pigment surface with, for example, ozone, hypochlorous acid, or fuming sulfuric acid.

[0117] When a dispersant is incorporated into an ink composition, it is preferable to use a dispersant having both a hydrophobic portion (hydrophobic group) and a hydrophilic portion (hydrophilic group) in its molecular structure. Such a dispersant has the effect of the hydrophobic portion adsorbing to the surface of the colorant particles and the hydrophilic portion orienting towards the aqueous medium side of the ink composition. This action tends to make it possible to include the colorant as a dispersion in the ink composition more stably. Such dispersants are not particularly limited, but examples include acrylic resins, styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid-(meth)acrylate copolymers and other styrene-acrylic resins, styrene-maleic acid resins, and their salts, formalin condensates of aromatic sulfonates, and one or more selected from this group can be used. Commercially available dispersants may also be used.

[0118] When dispersing pigments with a dispersant, the ratio of pigment to dispersant is preferably 10:1 to 1:10, and more preferably 4:1 to 1:3.

[0119] Alternatively, a method may be used in which the pigment particles are coated with a resin or other material to impart dispersibility. Possible methods for coating the pigment include acid precipitation, phase inversion emulsification, and miniemulsion polymerization.

[0120] The dyes used are not particularly limited and include acid dyes, direct dyes, reactive dyes, and basic dyes. Dyes may be used individually or in combination of two or more.

[0121] There are no particular restrictions on the dyes used, but for example, CI Acid Yellow 17, 23, 42, 44, 79, 142; CI Acid Red 52, 80, 82, 249, 254, 289; CI Acid Blue 9, 45, 249; CI Acid Black 1, 2, 24, 94; CI Food Black 1, 2; CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 14 Examples include 2, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Direct Black 19, 38, 51, 71, 154, 168, 171, 195, CI Reactive Red 14, 32, 55, 79, 249, and CI Reactive Black 3, 4, 35.

[0122] The colorant content is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, even more preferably 1 to 8% by mass, even more preferably 1.5 to 6% by mass, and particularly preferably 2 to 5% by mass, relative to the total amount of the colored ink composition.

[0123] 1.1.3.2 Water The colored ink composition is a water-based composition. The "water-based" composition in the colored ink composition can be the same as that of the clear ink composition described above.

[0124] The water content is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 55% by mass or more, relative to the total mass of the colored ink composition. There is no particular upper limit to the water content, but for example, it is preferably 99% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less, relative to the total mass of the colored ink composition.

[0125] 1.1.3.3 Wax The colored ink composition may contain wax. The composition of wax in the colored ink composition can be the same as that of the clear ink composition described above.

[0126] The wax content is preferably 3% by mass or more, more preferably 5% by mass or more, and more preferably 8% by mass or more, based on the total mass of the colored ink composition. The upper limit of the wax content is preferably 20% by mass or less, more preferably 17% by mass or less, and even more preferably 15% by mass or less, based on the total mass of the colored ink composition.

[0127] 1.1.3.4 Fixing resin The colored ink composition may contain a fixing resin. The composition of the fixing resin in the colored ink composition can be the same as that of the clear ink composition described above.

[0128] 1.1.3.5 Organic Solvents The colored ink composition may contain an organic solvent. The composition of the organic solvent in the colored ink composition can be the same as that of the clear ink composition described above.

[0129] 1.1.3.6 Glycol ether-based solvents The colored ink composition may contain a glycol ether-based solvent. The composition of the glycol ether-based solvent in the colored ink composition can be the same as that of the clear ink composition described above.

[0130] 1.1.3.7 Surfactants The colored ink composition may contain a surfactant. The surfactant composition in the colored ink composition can be the same as that of the clear ink composition described above.

[0131] 1.1.3.8 Other Ingredients The colored ink composition may optionally contain additives such as pH adjusters, preservatives / fungal agents, rust inhibitors, chelating agents, viscosity modifiers, solubilizers, and antioxidants. When such additives are included, the content is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.1 to 1% by mass, relative to the total amount of the colored ink composition.

[0132] 1.1.3.9 Physical Properties The surface tension and viscosity of the colored ink composition can be the same as those of the clear ink composition described above.

[0133] 1.1.4 Recording media The recording medium used in the recording method according to this embodiment is not particularly limited, and examples include absorbent recording media, low absorbent recording media, non-absorbent recording media, etc.

[0134] Low-absorbent or non-absorbent recording media refer to recording media that do not absorb liquid at all or absorb very little liquid. Quantitatively, low-absorbent or non-absorbent recording media are defined as "record media that do not absorb liquid at all or very little liquid in the Bristow method from the start of contact for 30 msec." 1 / 2 Up to 10 mL / m² of water absorption capacity 2This refers to the recording media 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). Details of the test method are described in standard No. 51 "Paper and cardboard - Liquid absorbency test method - Bristow method" of the "JAPAN TAPPI Paper & Pulp Test Methods 2000 Edition". In contrast, absorbent recording media refer to recording media that do not fall under the category of low-absorbent or non-absorbent recording media.

[0135] Examples of low-absorption recording media include recording media with a low-absorption coating layer on their surface, known as coated paper. Examples of paper-based recording media include art paper, coated paper, matte paper, and other printing papers. Examples of plastic-based recording media 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.

[0136] Examples of non-absorbent recording media include those in which a plastic coating is applied to a substrate such as paper, those in which a plastic film is adhered to a substrate such as paper, and plastic films that do not have an absorbent layer (receiving layer). Examples of such plastics include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

[0137] Among these, it is more preferable to use a recording medium that is a polyolefin-based film substrate. "Polyolefin-based" is a general term for polymers that use alkenes (olefins) as monomers. Examples include polyethylene and polypropylene.

[0138] From the viewpoint of enjoying the effects of the present invention, it is preferable that the recording medium used in the recording method according to this embodiment is a non-absorbent or low-absorbent recording medium having an in-plane surface roughness (Sa) of 0.2 μm or more. Such recording media are particularly prone to the problem of ink peeling off from the image area and adhering to the non-image area, resulting in staining where the peeled ink hardens on the non-image area. However, with the recording method according to this embodiment, even with such a recording medium, it is possible to reduce staining in the non-image area (achieve good scratch resistance) while maintaining good productivity.

[0139] "In-plane surface roughness (Sa)" represents the average of the absolute values ​​of the height differences (z(x,y)) from the mean surface at each measurement point in reference region A, and is expressed by the following formula. Details of "In-plane surface roughness (Sa)" are specified in ISO 25178. "In-plane surface roughness (Sa)" is also called "arithmetic mean height Sa". Sa = (1 / A)∬ A |z(x,y)|dxdy

[0140] Surface roughness Sa can be measured, for example, using a laser microscope (VK-X1000 / Keyence) in accordance with ISO 25178.

[0141] The surface roughness Sa of the surface to which the ink of the recording medium is attached is preferably 0.3 μm or more, more preferably 0.4 μm or more, even more preferably 0.5 μm or more, and particularly preferably 0.6 μm or more. There is no particular upper limit to the surface roughness Sa, but it is preferably 1.5 μm or less, preferably 1.0 μm or less, and more preferably 0.8 μm or less.

[0142] The recording medium may contain inorganic particles on the surface of the substrate. Preferably, the inorganic particles include silica such as colloidal silica, inorganic oxides such as titanium dioxide, aluminum oxide (alumina), zinc oxide, antimony oxide, magnesium oxide, and zirconium oxide, inorganic carbonates such as calcium carbonate, or inorganic sulfates such as calcium sulfate, and mixtures thereof may also be used.

[0143] The shape of the inorganic particles may be, for example, spherical, rod-shaped, bead-like (spherical particles linked together), needle-shaped, etc. Among these, spherical or rod-shaped is preferred, and spherical is particularly preferred.

[0144] The shape of inorganic particles can be confirmed by observation with a scanning electron microscope. In the present invention, "spherical" means that when observed with a scanning electron microscope, it does not mean that primary particles are linked together in a bead-like, rod-like, needle-like, etc., and is not limited to perfect spheres or ellipsoids.

[0145] 1.2 Drying process The recording method according to this embodiment may include a drying step (primary drying step) for drying the recording medium in the colored ink application step and the clear ink application step described above. Including such a drying step allows the ink to dry more quickly, which tends to further improve scratch resistance and image quality.

[0146] The primary drying process involves heating or blowing air onto the recording medium to quickly dry the ink. The primary drying process dries at least a portion of the solvent component of the ink that has adhered to the recording medium, to the extent that it reduces the flow of the ink. The primary drying process may be carried out so that the ink adheres to the heated recording medium, or it may be carried out early after adhesion to accelerate drying.

[0147] In the primary drying process, it is preferable that the ink droplets that have landed on the recording medium begin to dry no later than 0.5 seconds after landing. The drying unit (drying mechanism) for drying the ink on the recording medium is not particularly limited, but examples include platen heaters, hot air heaters, IR heaters, etc., which have a heating function, and blowers, etc., which do not have a heating function.

[0148] Types of drying mechanisms include conduction type, which heats the recording medium by transferring heat from a component in contact with the recording medium to the recording medium; radiation type, which heats the recording medium by radiating radiation such as IR to the recording medium; and airflow type, which blows air towards the recording medium.

[0149] The blower method (blowing process) includes methods that heat the recording medium while applying hot air, and methods that promote ink drying with room temperature air without heating. The method without heating is preferable because it suppresses the drying of ink in the inkjet head nozzles and the resulting decrease in ejection stability. It is also preferable to use the blower method in combination with either the conduction method or the radiation method. When used in combination, the blower method may also be a method without heating, which is preferable.

[0150] In the primary drying process, the surface temperature of the recording medium portion facing the inkjet head is preferably 60°C or lower, more preferably 55°C or lower. Furthermore, it is preferably 50°C or lower, even more preferably 45°C or lower. On the other hand, it is preferably 20°C or higher, more preferably 25°C or higher, even more preferably 30°C or higher, particularly preferably 35°C or higher, and even more particularly preferably 40°C or higher. Furthermore, it is preferably 30 to 60°C, even more preferably 35 to 55°C. Even more preferably 40 to 50°C.

[0151] When the surface temperature of the recording medium is within the above range, drying properties are improved, and the abrasion resistance of the resulting recorded material tends to be improved. Furthermore, clogging recovery, ejection stability, and color development are also better, which is preferable.

[0152] Furthermore, the primary drying process may be omitted, or the primary drying process may not involve heating. In this case, the surface temperature of the recording medium on the platen should remain below the above range.

[0153] Furthermore, when using a forced-air method (where the primary drying process includes a forced-air process), the wind speed near the recording medium is preferably 0.2 m / s or more, more preferably 0.5 m / s or more, even more preferably 1.0 m / s or more, particularly preferably 1.5 m / s or more, and most particularly preferably 2.0 m / s or more. On the other hand, it is preferably 20 m / s or less, more preferably 15 m / s or less, even more preferably 10 m / s or less, and particularly preferably 5 m / s or less. Furthermore, a speed of 0.5 to 10 m / s is preferred, 1 to 4 m / s is more preferred, and 2 to 3 m / s is even more preferred. The air temperature is preferably 45°C or lower, more preferably 40°C or lower, even more preferably 32°C or lower, and particularly preferably 20-27°C.

[0154] 1.3 Secondary drying process The recording method according to this embodiment may include a heating step (secondary heating step) for heating a recording medium to which a colored ink composition and a clear ink composition have been attached. The secondary heating step is a step of heating the recording medium sufficiently to complete the recording and to the point where the recorded material can be used. The secondary heating step is also a step of heating the solvent components of the ink and the fixing resin contained in the ink to flatten the ink coating film.

[0155] The secondary heating step is preferably started more than 0.5 seconds after the ink adheres to the recording medium. For example, it is preferable to start heating a recording area of ​​the recording medium more than 0.5 seconds after the ink has completely adhered to that area.

[0156] The surface temperature of the recording medium in the secondary heating step is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher. In the secondary heating step, heating the surface temperature of the recording medium to 60°C or higher tends to result in excellent drying properties and better moisture resistance and friction resistance. The upper limit is preferably 100°C or lower, and more preferably 90°C or lower.

[0157] Furthermore, the secondary heating mechanism can be a conduction type, a radiation type, a forced-air type, or the like.

[0158] 2. Recording device A recording device according to one embodiment of the present invention is a recording device that performs the above-described recording method, and comprises the above-described colored ink composition, the above-described clear ink composition, and an inkjet head that ejects the colored ink composition and the clear ink composition.

[0159] The recording device according to this embodiment performs the recording method described above, and is capable of reducing contamination in non-image areas (achieving good scratch resistance) while maintaining good productivity.

[0160] The recording device according to this embodiment will be described below with reference to the drawings.

[0161] Figure 1 is a schematic cross-sectional view of the inkjet recording device 1. 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 ventilation fan 8, a carriage 9, a platen 11, a carriage movement mechanism 13, a transport means 14, and a control unit CONT. The operation of the entire inkjet recording device 1 is controlled by the control unit CONT shown in Figure 2.

[0162] The inkjet head 2 has an inkjet head 2a that ejects a colored ink composition and an inkjet head 2b that ejects a clear ink composition, and can record onto the recording medium M by ejecting the colored ink composition and the clear ink composition from the nozzles of the respective inkjet heads and adhering them to the recording medium M.

[0163] In this embodiment, the inkjet head 2 is a serial inkjet head that scans the recording medium M multiple times in the main scanning direction relative to the recording medium M to deposit the colored ink composition and the clear ink composition onto the recording medium M. The inkjet head 2 is mounted on a 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 a carriage movement mechanism 13 that 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.

[0164] Figure 3 shows an arrangement in which an inkjet head 2a that ejects a colored ink composition and an inkjet head 2b that ejects a clear ink composition are positioned side by side at the same location with respect to the transport direction (T2 direction) of the recording medium M. When projected in the main scanning direction, the inkjet heads 2a and 2b have overlapping positions in the transport direction (T2 direction).

[0165] For example, with such an arrangement, clear ink can be deposited on the non-image area in the same scan as the deposit of colored ink on the image area. That is, the colored ink composition can be deposited on the image area of ​​a certain scanning region of the recording medium, and the clear ink composition can be deposited on the non-image area of ​​a certain scanning region in the same scan. In this case, when depositing clear ink on the image area, the colored ink composition and the clear ink composition are deposited on the recording medium in the same main scanning region using the same main scan.

[0166] The nozzle rows shown in Figure 3 are the nozzle rows that eject ink from each inkjet head.

[0167] Figure 4 shows an arrangement in which the inkjet head 2b, which ejects the clear ink composition, is positioned downstream of the inkjet head 2a, which ejects the colored ink composition, in the transport direction (T2 direction) of the recording medium M. When projected in the main scanning direction, the inkjet heads 2a and 2b do not have any overlapping positions in the transport direction (T2 direction).

[0168] For example, with such an arrangement, the colored ink composition and the clear ink composition can be attached to the recording medium in sequence, and the clear ink composition can be attached on top of the colored ink composition. That is, the colored ink composition can be attached to the image portion of a scanning area of ​​the recording medium, and the clear ink composition can be attached to the image portion and non-image portion of a certain scanning area in a scan after that scan. In this case, when attaching the clear ink to the image portion, the colored ink composition can be attached to the main scanning area by a certain main scan, and the clear ink composition can be attached on top of the main scanning area in a main scan after that main scan.

[0169] The nozzle rows shown in Figure 4 are the nozzle rows that eject ink from each inkjet head.

[0170] Here, the main scanning direction is the direction in which the carriage 9, equipped with the inkjet head 2, moves. In Figure 1, this is the direction that 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. In other words, the color ink adhesion process and the clear ink adhesion process are performed by multiple main scans in which the inkjet head 2 moves in the main scanning direction, and multiple sub-scans in which the recording medium M moves in the sub-scanning direction that intersects with the main scanning direction.

[0171] The cartridge 12 that supplies ink 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 may be filled with a different type of ink, and ink is 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, with ink supplied to each nozzle by a supply pipe (not shown).

[0172] 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.

[0173] The inkjet recording device 1 is equipped with a ventilation fan 8, an IR heater 3, and a platen heater 4 for drying the ink ejected from the inkjet head 2 and adhering to the recording medium M. The primary drying process can be performed by using these ventilation fan 8, IR heater 3, and platen heater 4 in appropriate combinations. In the primary drying process, it is not always necessary to heat the recording medium M; the ventilation fan 8 may be used alone to provide airflow at room temperature.

[0174] 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. In addition, various fans (e.g., ventilation fan 8) may be provided to dry the ink on the recording medium M by blowing warm air or air at the same temperature as the environment onto the recording medium M.

[0175] The platen heater 4 can heat the recording medium M via the platen 11 at a position opposite the inkjet head 2 so that the ink ejected by the inkjet head 2 can dry quickly from the moment it adheres to the recording medium M. The platen heater 4 can heat the recording medium M by conduction, thereby allowing ink to adhere to the heated recording medium M.

[0176] Furthermore, it is preferable that the surface temperature of the recording medium M, due to heating by the IR heater 3 and the platen heater 4, be within the range described in the primary drying step above.

[0177] The heating element 5 is a heater for secondary heating, which dries and solidifies the ink attached to the recording medium M. The heating element 5 can be used in the secondary heating process. When the heating element 5 heats the recording medium M on which the image is recorded, moisture and other substances contained in the ink evaporate more quickly, and an ink film is formed by the fixing resin contained in the ink composition. In this way, the ink film is firmly fixed or adhered to the recording medium M, resulting in excellent film-forming properties, and a high-quality image can be obtained in a short time.

[0178] The surface temperature of the recording medium M due to heating by the heating element 5 is preferably within the range described in the secondary heating step above. When the temperature is within the aforementioned range, high-quality images tend to be obtained in a short time.

[0179] 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.

[0180] Furthermore, the inkjet recording device 1 may be equipped with a preheater 7 that preheats the recording medium M before ink is applied to it. In addition, the inkjet recording device 1 may be equipped with a ventilation fan 8 to allow the ink applied to the recording medium M to dry more efficiently.

[0181] 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.

[0182] In another embodiment, the inkjet recording device may be a line-type inkjet recording device in which the inkjet head 2 is a line head. For example, in Figure 1, the inkjet head 2 is a line head having a length greater than or equal to the recording width in the width direction of the recording medium, and its position is fixed. Ink is ejected from the inkjet head 2 onto the conveyed recording medium M and adheres to the recording medium. In this case, recording is performed by a single main scan. When the inkjet head 2 is a line head, the other configurations can be the same as in the serial type described above.

[0183] 3. Examples The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" below refers to mass.

[0184] 3.1 Preparation of colored ink composition and clear ink composition The components are placed in a container to achieve the composition shown in Table 1 (Figure 5), and mixed and stirred with a magnetic stirrer for 2 hours until thoroughly mixed. After stirring for 1 hour, the mixture is filtered using a 5.0 μm PTFE membrane filter to obtain the colored ink composition (C01) and the clear ink compositions (CL01~CL17). Water is added so that the total amount of each composition is 100% by mass. The colorant, fixing resin, and wax are the solid components of the colorant, fixing resin, and wax, respectively.

[0185] Furthermore, the colorant is used as a resin-dispersed pigment dispersion. The resin-dispersed pigment dispersion is obtained by thoroughly mixing 15 parts by mass of CI pigment blue (15:3), 10 parts by mass of ammonium salt of styrene-acrylic acid copolymer (weight-average molecular weight 10,000) as a dispersant, and 55 parts by mass of ion-exchanged water. This mixture is then dispersed in a sand mill (manufactured by Yaskawa Manufacturing Co., Ltd.) with glass beads (1.7 mm in diameter, 1.5 times the amount of solids in the mixture) for 2 hours, and the glass beads are removed after dispersion.

[0186] Further explanation regarding Table 1 is provided below. <Fixing resin> • Styrene acrylic resin (Joncryl 537J, trade name, manufactured by BASF) <wax> • Modified paraffin wax (AQUACER539, product name, manufactured by Big Chemie Japan Co., Ltd.) • Polyethylene wax A (AQUACER515, product name, manufactured by Big Chemie Japan Co., Ltd.) • Polyethylene wax B (AQUACER531, product name, manufactured by Big Chemie Japan Co., Ltd.) <Surfactants> • Silface SAG503A (product name, manufactured by Nisshin Chemical Industry Co., Ltd., silicone-based surfactant)

[0187] The volume-average particle size (D50) of the wax is measured using a NANOTRACKWAVE II nanoparticle size analyzer manufactured by Microtrac after diluting the product 400 times.

[0188] 3.2 Printing method A modified SC-S80650 (manufactured by Seiko Epson) machine is prepared, and each ink obtained above is filled under the conditions shown in Tables 2 and 3 (Figures 6 and 7). The nozzle density of the nozzle row of the print head is 360 dpi. A platen heater and a feed fan are provided, and the fan speed is set to the values ​​shown in Tables 2 and 3. The wind speed is the wind speed near the surface of the recording medium, and the wind temperature is set to 25°C. The primary heating temperature (surface temperature of the recording medium) during the ink adhesion process is set to the temperatures shown in Tables 2 and 3. Secondary heating is performed using a downstream secondary heater at a surface temperature of 70°C for the recording medium.

[0189] Printing should be performed in the order of Record 1 and Record 2 in Tables 2 and 3. Here, Record 1 and Record 2 in Tables 2 and 3 show the printing conditions for the clear ink composition. A print area A indicates that the clear ink composition is applied to the non-image area (no clear ink composition is applied to the image area). A print area of ​​B indicates that the clear ink composition is applied to the entire surface (the clear ink composition is applied to both the image area and the non-image area). A print area designated as "C" indicates that the clear ink composition is applied to the image area (no clear ink composition is applied to the non-image area).

[0190] In Record 1, a scan is performed to deposit the colored ink composition onto the image portion of a scanning area on the recording medium, and then, in the same scan, the clear ink composition is deposited under the conditions shown in Tables 2 and 3. Specifically, if the print area of ​​Record 1 is A, a scan is performed to adhere the clear ink composition to the image portion of a certain scanning area of ​​the recording medium, and the clear ink composition is adhered to the non-image portion of a certain scanning area using the same scan. If the print area of ​​Record 1 is B, a scan is performed to adhere the clear ink composition to the image portion of a certain scanning area of ​​the recording medium, and the clear ink composition is adhered to both the image portion and the non-image portion of a certain scanning area using the same scan. If the print area of ​​Record 1 is C, a scan is performed to adhere the clear ink composition to the image portion of a certain scanning area of ​​the recording medium, and the clear ink composition is adhered to the image portion of a certain scanning area using the same scan. If the print area of ​​Record 1 is "-", a scan is performed to adhere the clear ink composition to the image portion of a certain scanning area of ​​the recording medium, but the clear ink composition is not adhered using the same scan.

[0191] In Record 2, the clear ink composition is applied under the conditions shown in Tables 2 and 3, during a scan that follows the scan in Record 1. Specifically, if the print area of ​​Record 2 is A, the clear ink composition is applied to the non-image portion of a certain scan area during a scan that follows the scan in Record 1. If the print area of ​​Record 2 is B, the clear ink composition is applied to both the image and non-image portions of a certain scan area during a scan that follows the scan in Record 1. If the print area of ​​Record 2 is C, the clear ink composition is applied to the image portion of a certain scan area during a scan that follows the scan in Record 1. If the print area of ​​Record 2 is "-", no clear ink composition is applied during a scan that follows the scan in Record 1.

[0192] The amount of colored ink composition adhering to the recording pattern is 6 mg / inch. 2 The amount of clear ink composition applied shall be the values ​​shown in Tables 2 and 3. The recording pattern shall be solid color printing. The recording resolution shall be 720 x 720 dpi, and the above recording resolution shall be achieved by subtracting the number of ink droplets per pass for all pass counts.

[0193] The recording medium used for printing is "Yupo 80 (UV) PA-T1" (product name of Lintec Corporation, in-plane surface roughness (Sa) of the substrate = 0.7 μm). The surface roughness was measured using a laser microscope VK-X1000, and the in-plane surface roughness (Sa) was measured with a 20x objective lens.

[0194] Records relating to each example and each comparative example are prepared using the printing method described above.

[0195] 3.3 Evaluation Method 3.3.1 Abrasion resistance evaluation The recordings for each example and comparative example are subjected to friction using a JSPS friction durability tester (Tester Industries Co., Ltd., AB-301S) by applying 500g of friction to the image portion of the recording 30 times in the long-side direction with a friction element. The non-image portion of the recording being tested is used as the friction element. Furthermore, the friction element is made to move back and forth across the image portion during friction. In other words, the recording area of ​​the recording is rubbed from one end to the other across the image portion in the long-side direction. The abrasion resistance is determined according to the following evaluation criteria. [Evaluation Criteria] A: No color transfer to the friction element or soiling of the printed surface was observed. B: Color transfer to the friction element is observed, but no soiling of the printed surface is found. C: There is some background staining on the printed surface, but it is not very noticeable. Color transfer to the friction element is observed. D: The printed surface shows noticeable dirt. Color transfer to the friction element is observed.

[0196] 3.3.2 Image Quality (Blurring) Evaluation A recorded material is obtained in the same manner as the above printing method, except that the recording pattern is a 1 mm wide grid of colored ink composition. The bleeding of clear ink at the boundary between the image area and the non-image area is visually checked, and the image quality (bleeding) is determined according to the following evaluation criteria. [Evaluation Criteria] A: No bleeding is visible. B: When viewed from close range, the blurring is noticeable. C: There is some bleeding, but it is not noticeable. D: The bleeding is noticeable.

[0197] 3.3.3 Evaluation of ink ejection stability (clear ink) Record for 2 hours under the above printing method conditions. However, after recording, simulated recording will be performed in which no ink is ejected from the print head. After recording, suction cleaning will be performed to restore non-ejecting nozzles, and then nozzle inspection will be conducted. One cleaning cycle will eject 1 cc of ink from the nozzle row. Ejection stability (clear ink) will be judged according to the following evaluation criteria. Note that the judgment will be made on nozzles that eject clear ink. [Evaluation Criteria] A: All nozzles are restored after one cleaning. B: All nozzles recovered after 3 cleaning cycles. C: All nozzles recovered after 6 cleaning cycles. D: Some nozzles do not recover after 6 cleaning cycles.

[0198] 3.3.4 Productivity Evaluation Productivity is determined based on the number of passes required to record in a predetermined width main scanning area in the printing method relating to each embodiment and each comparative example, according to the following evaluation criteria. [Evaluation Criteria] A: 5 passes or less. B: More than 5 passes and 7 passes or less. C:7 Passes Exceeding

[0199] 3.4 Evaluation Results The evaluation results are shown in Tables 2 and 3. The system comprises a colored ink application step in which an aqueous colored ink composition containing a colorant is ejected from an inkjet head and adhered to a recording medium, and a clear ink application step in which an aqueous clear ink composition is ejected from an inkjet head and adhered to a recording medium. The colored ink application step and the clear ink application step are performed by scanning, in which ink is ejected from the inkjet head and adhered to the recording medium while moving the relative position of the inkjet head and the recording medium. The colored ink composition is adhered to the image portion of a scanning area of ​​the recording medium, the clear ink composition is adhered to the non-image portion of a scanning area in the same scan, and the clear ink composition is adhered to both the image portion and the non-image portion of a scanning area in a scan after the first scan, with the total amount of the clear ink composition adhered to the non-image portion being 3 mg / inch. 2 The clear ink composition contains wax and a fixing resin, wherein the wax content is 0.7% by mass or more relative to the total mass of the clear ink composition, and the combined content of wax and fixing resin is 4.5% by mass or more relative to the total mass of the clear ink composition. The recording method according to each embodiment can reduce contamination in the non-image portion, which is the part of the recording that does not have an image recorded on it (good scratch resistance is obtained) without increasing the time required for recording (while maintaining good productivity).

[0200] In contrast, the recording methods for each comparative example that do not satisfy the above configuration are inferior in at least one of the following: productivity or abrasion resistance.

[0201] The following conclusions can be drawn from the embodiments described above.

[0202] One method of recording is: A colored ink application process involves ejecting a water-based colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium. The system includes a clear ink application step in which a water-based clear ink composition is ejected from an inkjet head and adhered to a recording medium, The colored ink application step and the clear ink application step are performed by scanning, in which ink is ejected from the inkjet head and applied to the recording medium while moving the relative position of the inkjet head and the recording medium. The colored ink composition is applied to the image portion of a scanning area of ​​the recording medium, In the same scan as the said scan, the clear ink composition is applied to the non-image portion of a certain scanning area. In a scan following the said scan, the clear ink composition is applied to the image portion and the non-image portion of a certain scanning area. The total amount of the clear ink composition adhering to the non-image area is 3 mg / inch 2 That's all. The clear ink composition contains wax and a fixing resin. The wax content is 0.7% by mass or more relative to the total mass of the clear ink composition. The total content of the wax and the fixing resin is 4.5% by mass or more relative to the total mass of the clear ink composition.

[0203] In one embodiment of the above recording method, In the aforementioned clear ink composition, The total content of the wax and the fixing resin is 5.0% by mass or more and 10.0% by mass or less relative to the total mass of the clear ink composition. The wax content may be 1.0% by mass or more and 3.0% by mass or less based on the total mass of the clear ink composition.

[0204] In any embodiment of the above recording method, The colored ink application step and the clear ink application step may include a drying step for drying the recording medium.

[0205] In any embodiment of the above recording method, The clear ink composition may not contain more than 2.0% by mass of glycol ether-based solvent relative to the total mass of the clear ink composition.

[0206] In any embodiment of the above recording method, The amount of the clear ink composition adhering to the image portion of a certain scanning area during the same scan is 1.5 mg / inch. 2 The following is acceptable:

[0207] In any embodiment of the above recording method, The volume-average particle size (D50) of the wax may be 50 nm or larger.

[0208] In any embodiment of the above recording method, The wax may contain polyolefin wax.

[0209] In any embodiment of the above recording method, The aforementioned clear ink composition contains an organic solvent, The content of organic solvents with a standard boiling point of less than 200°C in the clear ink composition may be 50% by mass or more of the total content of the organic solvents.

[0210] In any embodiment of the above recording method, The recording medium may be a non-absorbent recording medium or a low-absorbent recording medium having an in-plane surface roughness (Sa) of 0.2 μm or more.

[0211] One embodiment of a recording device is: A recording device that performs any of the above-described recording methods, The system comprises the colored ink composition, the clear ink composition, and an inkjet head for ejecting the colored ink composition and the clear ink composition.

[0212] The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes configurations that are substantially identical to the configurations described in the embodiments, for example, configurations that have the same function, method and result, or configurations that have the same purpose and effect. The present invention also 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 the configurations described in the embodiments. Furthermore, the present invention includes configurations that add known technology to the configurations described in the embodiments. [Explanation of Symbols]

[0213] 1... Inkjet recording device, 2... Inkjet head (2a... Inkjet head for ejecting colored ink composition, 2b... Inkjet head for ejecting clear ink composition), 3... IR heater, 4... Platen heater, 5... Heating heater, 6... Cooling fan, 7... Preheater, 8... Ventilation fan, 9... Carriage, 11... Platen, 12... Cartridge, 13... Carriage moving mechanism, 14... Transport means, CONT... Control unit, MS... Main scanning direction, SS... Sub-scanning direction, M... Recording medium.

Claims

1. A colored ink application process involves ejecting a water-based colored ink composition containing a colorant from an inkjet head and adhering it to a recording medium. The system includes a clear ink application step in which a water-based clear ink composition is ejected from an inkjet head and adhered to a recording medium, The colored ink application step and the clear ink application step are performed by scanning, in which ink is ejected from the inkjet head and applied to the recording medium while moving the relative position of the inkjet head and the recording medium. The colored ink composition is applied to the image portion of a scanning area of ​​the recording medium, In the same scan as the said scan, the clear ink composition is applied to the non-image portion of a certain scanning area. In a scan following the said scan, the clear ink composition is applied to the image portion and the non-image portion of a certain scanning area. The total amount of the clear ink composition attached to the non-image area is 3 mg / inch. ２ That's all. The clear ink composition contains wax and a fixing resin. The wax content is 0.7% by mass or more relative to the total mass of the clear ink composition. A recording method wherein the total content of the wax and the fixing resin is 4.5% by mass or more relative to the total mass of the clear ink composition.

2. In the aforementioned clear ink composition, The total content of the wax and the fixing resin is 5.0% by mass or more and 10.0% by mass or less based on the total mass of the clear ink composition. The recording method according to claim 1, wherein the content of the wax is 1.0% by mass or more and 3.0% by mass or less with respect to the total mass of the clear ink composition.

3. The recording method according to claim 1 or claim 2, further comprising a drying step for drying the recording medium in the colored ink application step and the clear ink application step.

4. The recording method according to claim 1 or claim 2, wherein the clear ink composition does not contain a glycol ether-based solvent in an amount of 2.0% by mass or more relative to the total mass of the clear ink composition.

5. The amount of the clear ink composition adhering to the image portion of a certain scanning area during the same scan is 1.5 mg / inch. ２ The recording method according to claim 1 or claim 2, which is as follows:

6. The recording method according to claim 1 or claim 2, wherein the volume-average particle size (D50) of the wax is 50 nm or more.

7. The recording method according to claim 1 or claim 2, wherein the wax contains polyolefin wax.

8. The aforementioned clear ink composition contains an organic solvent, The recording method according to claim 1 or claim 2, wherein the content of an organic solvent with a standard boiling point of less than 200°C in the clear ink composition is 50% by mass or more of the total content of the organic solvent.

9. The recording method according to claim 1 or claim 2, wherein the recording medium is a non-absorbent recording medium or a low-absorbent recording medium having an in-plane surface roughness (Sa) of 0.2 μm or more on the surface of the recording medium.

10. A recording device that performs the recording method described in claim 1, A recording device comprising the colored ink composition, the clear ink composition, and an inkjet head for ejecting the colored ink composition and the clear ink composition.

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