JP5344133B2 - Inkjet printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method of inkjet recording system which permits high-speed printing for a recording medium of ink non-absorptivity and low-absorptivity, is excellent in image quality and scuffing resistance irrespective of ink absorptivity of the recording medium, and excellent in ejection stability as well. <P>SOLUTION: Disclosed is the printing method in which a color ink and a resin ink are applied onto the recording medium of ink non-absorptivity and low-absorptivity by an inkjet recording system using an aqueous ink set, to print an image, wherein the resin ink contains a thermoplastic resin particle which is insoluble in a water-soluble resin solvent and water, but is compatible with the water-soluble resin solvent, the resin particle includes a resin particle (A) of which the glass transition temperature is 20&deg;C or less and a wax particle (B), and a content of the resin particle in the resin ink is more than the content of a colorant in the color ink and a drying step is included during and/or after printing. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a printing method for forming an image by an ink jet recording method on a non-ink-absorbing and low-absorbing recording medium, and is excellent in image quality and abrasion resistance regardless of the ink absorptivity of the recording medium, and also in ejection stability. The present invention relates to an excellent ink jet recording method.

  The ink jet recording method is a recording method in which recording is performed by ejecting (discharging) ink droplets and attaching them to a recording medium such as paper. Due to recent advances in ink jet recording technology, ink jet recording methods have come to be used in the field of high-definition image recording (printing) that has so far been used for silver salt photography and offset printing. Therefore, one of the characteristics required for the ink used in the ink jet recording method is that ink droplets can be stably ejected for a long period of time so as not to disturb the image.

  In recent years, apart from recording media having high ink absorbability, it has been required to form images on ink non-absorbing and low-absorbing recording media by an ink jet recording method. As a printing method for forming an image on an ink non-absorbing and low-absorbing recording medium by an ink jet recording method, Japanese Patent Application Laid-Open No. 2000-44858 (Patent Document 1) discloses water, a glycol solvent, insoluble coloring. There has been proposed a method of printing an ink containing an agent, a polymer dispersant, a silicon surfactant and a fluorinated surfactant, a water-insoluble graft copolymer binder, and N-methylpyrrolidone on a hydrophobic substrate. Patent No. 3937170 (Patent Document 2) is selected from aqueous emulsion polymers having a glass transition temperature of 40 ° C. to 80 ° C., pigments, monoalkyl ethers of alkylene glycol, 2-pyrrole, N-methylpyrrolidone, and sulfolane. There has been proposed a method for providing an image of a water-soluble surface agent on a hydrophobic surface. Japanese Patent Application Laid-Open No. 2005-220352 (Patent Document 3) contains a polymer colloid for printing on a non-porous substrate comprising a volatile cosolvent having a boiling point of 285 ° C. or less, acid-functionalized polymer colloid particles, and a pigment colorant. Ink jet inks have been proposed.

  As an overcoat composition for imparting high resistance to an image after printing, Japanese Patent Application Laid-Open No. 2004-195451 (Patent Document 4) exceeded an aqueous carrier, a humectant, a surfactant, and an acid value of 110. Compositions containing addition polymers have been proposed. Further, Patent Document 1 described above proposes a printing method including a step of applying with an overcoat composition obtained by removing a colorant from an ink composition.

  However, when printing on ink-jet recording media with high absorbency because non-ink-absorbing and low-absorbing recording media do not have an ink absorbing layer / coloring layer, or the ink absorbing layer / coloring layer is poor. Compared to the above, since the ink tends to bleed and the color developability is low, there is a problem that sufficient image quality cannot be obtained with the above-described ink.

  In addition, it is preferable that the ink viscosity is low in order to print a high-resolution and high-quality image at a high speed. There are missing issues. On the other hand, if a large amount of colorant or resin component is added to the low-viscosity ink, it becomes difficult to ensure ejection stability in high-speed printing.

JP 2000-44858 A Japanese Patent No. 3937170 JP 2005-220352 A JP 2004-195451 A

  Therefore, the present invention can perform high-speed printing on a non-ink-absorbing and low-absorbing recording medium, and is excellent in image quality and abrasion resistance regardless of the ink absorptivity of the recording medium. Another object of the present invention is to provide an ink jet recording type printing method which is also excellent.

In order to solve the above problems, the printing method of the present invention prints an image by applying color ink and resin ink to a non-ink-absorbing or low-absorbing recording medium by an ink jet recording method using a water-based ink set. (1) The water-based ink set includes the color ink containing a colorant and the resin ink containing resin particles without containing a colorant, and (2) the color ink includes: At least a water-insoluble colorant, a water-soluble and / or water-insoluble resin component, a water-soluble solvent, and a surfactant. (3) Although the resin ink is insoluble in water-soluble resin solvent and water, The water-soluble resin solvent includes compatible thermoplastic resin particles. The resin particles include resin particles A having a glass transition temperature of 20 ° C. or lower and wax particles B, and the resin particles in the resin ink. Yes rate not less than the content of the colorant in the color ink, (4) viewed including the Drying process during printing, the resin particles A are selected from the group consisting of acrylic resins, urethane resins, epoxy resins The wax particles B are carnauba wax, candelix wax, beeswax, rice wax, lanolin, paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, petrolatum, montan wax, ozokerite, carbon wax, Hoechst It is at least one selected from the group consisting of wax, polyolefin wax, stearamide, α-olefin / maleic anhydride copolymer, and the content ratio of the resin particles A and the wax particles B is 1: 1 to 1. 10: 1 and the drying step is The recording medium is heated by a method, and the heating temperature is 40 ° C to 100 ° C.

  The color ink further includes a special color in addition to the process color, and the special color is composed of orange and green.

  Preferably, the resin particle A is a resin particle emulsion obtained by emulsion polymerization of an unsaturated monomer, and the wax particle B is a polyethylene wax having a melting point of 90 to 150 ° C. For example, the content ratio of the resin particles A and the wax particles B in the resin ink is in the range of 1: 1 to 10: 1.

  Preferably, the color ink and the resin ink include a silicon-based surfactant and an acetylene glycol-based surfactant.

  The printing apparatus of the present invention includes the above-described printing method.

  According to the printing method of the ink jet recording system of the present invention, high-speed printing is possible with respect to a non-ink-absorbing and low-absorbing recording medium. In addition, it is possible to provide an ink jet recording printing method which is excellent in discharge stability.

  An ink jet recording method printing method according to an embodiment of the present invention prints an image by applying color ink and resin ink to a non-ink-absorbing and low-absorbing recording medium by an ink jet recording method using a water-based ink set. (1) The water-based ink set includes the color ink containing a colorant and the resin ink containing resin particles without containing a colorant, and (2) the color ink includes: A water-insoluble colorant, a water-soluble and / or water-insoluble resin component, a water-soluble solvent, and a surfactant. (3) The resin ink is a water-soluble resin solvent, water-insoluble but the water-soluble The compatible resin solvent contains compatible thermoplastic resin particles, and the resin particles include resin particles A having a glass transition temperature of 20 ° C. or less and wax particles B, and resin particles in the resin ink. Content is not less than the content of the colorant in the color ink contains a (4) Printing during and / or printing after the drying process.

[recoding media]
In the present embodiment, the recording medium to be printed is a non-ink-absorbing and low-absorbing recording medium. A non-ink-absorbing and low-absorbing recording medium is a recording medium that does not have an ink absorbing layer or has a poor ink absorbing layer. More quantitatively, a non-ink-absorbing and low-absorbing recording medium has a water absorption of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method. A recording medium is shown. This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method". As a non-ink-absorbing recording medium, for example, a plastic film coated on a substrate such as a plastic film or paper that has not been surface-treated for inkjet printing (that is, an ink-absorbing layer is not formed). And those having a plastic film adhered thereto. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. Examples of the recording medium with low ink absorption include printing paper such as art paper, coated paper, and matte paper.

[Water-based ink set]
The aqueous ink set used for the printing method according to the present embodiment includes a color ink containing a colorant and a resin ink containing resin particles without containing the colorant. Color ink is ink for forming color and monochrome images on a recording medium. Furthermore, the resin ink is used mainly for the purpose of imparting abrasion resistance to the printed matter by printing before, during, or after printing the above-described color ink. Hereinafter, each ink will be described.

[Color ink]
As described above, the color ink contains at least a water-insoluble colorant, a water-soluble and / or water-insoluble resin component, a water-soluble solvent, and a surfactant. Examples of the water-insoluble colorant include water-insoluble dyes or pigments, and a pigment is preferable. This is because a printed matter printed with an ink using a pigment is excellent in storage stability such as water resistance, gas resistance and light resistance. As the pigment, any of known inorganic pigments, organic pigments, and carbon black can be used. Among these, carbon black and organic pigments are preferred from the viewpoints of good color development and low sedimentation, which makes it difficult to settle during dispersion. The water-soluble and / or water-insoluble resin component is composed of, for example, a dispersion resin or a resin emulsion. Since the pigment cannot exist stably in water as it is, it is used in ink in a state of being dispersed in water by a dispersion resin. In this case, a resin emulsion can be further added as necessary. When using a surface-treated pigment whose surface is chemically hydrophilized, a so-called resin emulsion in which a water-soluble resin or a water-insoluble resin is dispersed is added.

  In addition, by adding a water-soluble solvent and a surfactant to water-based inks, ink wettability with respect to various recording media is improved, and color inks are particularly suitable for recording media that are difficult to wet with water. So that printing unevenness and the like can be reduced.

  The color ink preferably includes a special color in addition to the process colors of yellow, magenta, cyan, and black, and more preferably the special color is composed of orange and green. A non-ink-absorbing and low-absorbing recording medium does not have or lacks an ink absorbing layer / color-developing layer, and therefore has a lower color development than when printing on an ink-jet recording medium having high absorbency. For this reason, by adding a special color in addition to the process color, it is possible to obtain a high color even if the absorbency is low. Special colors include red, green, blue, orange, violet, and the like, with orange and green being particularly preferred.

  The color ink preferably contains a silicon-based surfactant and an acetylene glycol-based surfactant. By using a combination of a silicon surfactant and an acetylene glycol surfactant, the ink can be similarly wetted to a wide range of recording media from non-absorbing to low-absorbing, and a printed matter with less printing unevenness can be obtained. Can do.

  Furthermore, the color ink can further contain a moisturizing agent, preservative / fungicidal agent, pH adjusting agent, dissolution aid, antioxidant, metal trapping agent, and the like, if necessary.

  Next, each component constituting the color ink will be described.

(Coloring agent)
The colorant used for the color ink is a water-insoluble colorant, a so-called pigment, and is preferably selected as appropriate from organic pigments and carbon black.

Specific examples of carbon black include furnace black, lamp black, acetylene black, channel black and the like (CI Pigment Black 7). 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, etc. (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U , Special Black 6, 5, 4A, 4, 250, etc. (all trade names, manufactured by Degussa), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, etc. (all trade names, Colombia) (Manufactured by Carbon Co., Ltd.), Regar 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12, etc. (all trade names, manufactured by Cabot Corporation). In addition, these are description of an example of the carbon black suitable for this invention, and this invention is not limited by these. These carbon blacks may be used alone or as a mixture of two or more.
These pigments are added in an amount of 0.5 to 12% by mass, preferably 2 to 8% by mass, based on the total amount of the black ink.

  Organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolo Examples include pyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments.

  Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 16, 22, 60, etc .; I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and 60 selected from the group consisting of 60 or more.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, and 209, C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Violet 19.

  Examples of pigments used in yellow ink include C.I. I. 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 C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138.

  Examples of the pigment used for the orange ink include C.I. I. Pigment Orange 36 or 43, or a mixture thereof.

  Examples of pigments used in green ink include C.I. I. Pigment Green 7 or 36 or a mixture thereof.

  These pigments may be used by dispersing the resin using a dispersing resin, or may be used as a self-dispersing pigment by oxidizing or sulfonating the pigment surface with ozone, hypochlorous acid, fuming sulfuric acid or the like.

  These pigments are contained in an amount of about 0.5% to 15% by mass, preferably about 2% to 10% by mass, based on the total amount of ink of each color.

(Resin component)
The resin components listed below are preferred. Since these resins are water-insoluble and require water dispersibility, they are preferably polymers having both a hydrophilic part and a hydrophobic part.

  Specific examples of the resin component include acrylic polymers such as polyacrylate esters or copolymers thereof, polymethacrylate esters or copolymers thereof, polyacrylonitrile or copolymers thereof, polycyanoacrylates, and polyacrylamides. , Polyacrylic acid, or polymethacrylic acid; polyolefin polymers such as polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene, or copolymers thereof, petroleum resins, coumarone-indene resins, or terpene resins; vinyl acetate vinyl Alcohol-based polymers such as polyvinyl acetate or copolymers thereof, polyvinyl alcohol, polyvinyl acetal, or polyvinyl ether; halogen-containing polymers such as polyvinyl chloride or copolymers thereof , Polyvinylidene chloride, fluororesin, or fluororubber; nitrogen-containing vinyl polymer such as polyvinyl carbazole, polyvinyl pyrrolidone or copolymer thereof, polyvinyl pyridine, or polyvinyl imidazole; diene polymer such as polybutadiene or copolymer thereof A polymer, polychloroprene, or polyisoprene (butyl rubber); or other ring-opening polymerization resin, condensation polymerization resin, natural polymer resin, or the like can be used.

  Furthermore, Hitech E-7025P, Hitech E-2213, Hitech E-9460, Hitech E-9015, Hitech E-4A, Hitech E-5403P, Hitech E-8237 (all trade names, manufactured by Toho Chemical Co., Ltd.), AQUACER 507 , AQUACER 515, AQUACER 840 (all trade names, manufactured by Big Chemie Japan Co., Ltd.) and the like.

  The resin component may be mixed with other components in the aqueous ink as a fine particle powder. However, the resin fine particles are dispersed in an aqueous medium to form a resin emulsion, and then mixed with the other components of the aqueous ink. Is preferred.

  If the resin is obtained in the form of an emulsion, it can be prepared by mixing the resin particles in water, optionally with a surfactant. For example, an emulsion of an acrylic resin or a styrene-acrylic acid copolymer resin is composed of a (meth) acrylic ester resin or a styrene- (meth) acrylic ester resin, and optionally a (meth) acrylic resin, It can be obtained by mixing the active agent with water. The mixing ratio of the resin component and the surfactant is usually preferably about 50: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when the amount exceeds the above range, the water resistance of the ink tends to decrease or the adhesion tends to deteriorate. Absent.

The surfactant used here is not particularly limited, but preferred examples include anionic surfactants (for example, sodium dodecyl benzan sulfonate, sodium laurylate, ammonium salt of polyoxyethylene alkyl ether sulfate, etc.), nonions Surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, etc. These can be used as a mixture of two or more.
The resin emulsion can also be obtained by emulsion polymerization of the above resin component monomers in water in the presence of a polymerization catalyst and an emulsifier. A polymerization initiator, an emulsifier, and a molecular weight modifier used in the emulsion polymerization can be used according to a conventional method.

  As the polymerization initiator, those used for normal radical polymerization are used, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, Examples include peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide, and the like. When the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable. Examples of the emulsifier include sodium lauryl sulfate, those generally used as an anionic surfactant, nonionic surfactant or amphoteric surfactant, and mixtures thereof. These can be used in combination of two or more.

  Commercially available resin emulsions can also be used as the resin emulsion. For example, Microgel E-1002, E-5002 (styrene-acrylic resin emulsion; manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion; Dai Nippon Ink Chemical Co., Ltd.), Boncoat 5454 (styrene-acrylic resin emulsion; Dainippon Ink and Chemicals Co., Ltd.), SAE1014 (styrene-acrylic resin emulsion; manufactured by Nippon Zeon Co., Ltd.), or Cybinol SK- 200 (acrylic resin emulsion; manufactured by Seiden Chemical Co., Ltd.).

  From the viewpoint of long-term storage stability and ejection stability of the water-based ink, the resin fine particles preferably used in the present invention have a particle size in the range of 5 nm to 400 nm, more preferably in the range of 50 nm to 200 nm.

  The resin component is preferably included in a range of 0.1% by mass to 15.0% by mass in terms of solid content, and in a range of 0.5% by mass to 10.0% by mass with respect to the total amount of ink of each color. More preferably it is included. By being within this range, the color ink can be solidified and fixed even on a non-ink-absorbing or low-absorbing recording medium. When the content is less than 0.1% by mass, the ink solidification / fixing strength is weakened, and it may be easily peeled off from the surface of the recording medium. On the other hand, if the content exceeds 15% by mass, the storage stability and ejection stability of the color ink may not be ensured.

(Water-soluble solvent)
Examples of the water-soluble solvent include monohydric alcohols or polyhydric alcohols and derivatives thereof. These have the effect of further increasing the wettability of the color ink with respect to the recording medium and wetting it uniformly in synergy with a silicon surfactant and an acetylene glycol surfactant described later. For this reason, it is preferable to include the above-mentioned water-soluble solvent in the color ink because printing unevenness and bleeding of the ink can be reduced.

  As the monohydric alcohol, a monohydric alcohol having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, i-propanol, or n-butanol can be used.

  As polyhydric alcohols and derivatives thereof, divalent to pentavalent alcohols having 2 to 6 carbon atoms and complete or partial ethers of them with lower alcohols having 1 to 4 carbon atoms can be used. Here, the polyhydric alcohol derivative is an alcohol derivative in which at least one hydroxyl group is etherified, and does not mean a polyhydric alcohol itself that does not contain an etherified hydroxyl group.

  Specific examples of these polyhydric alcohols and their lower alkyl ethers include 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octane. Diols, diols such as 1,3-octanediol, 1,2-pentanediol, mono-, di- or triethylene glycol-mono or di-alkyl ether, mono-, di- or tripropylene glycol-mono or di-alkyl ether Preferably, 1,2-hexanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, or propylene glycol monobutyl , And the like ether.

  The content of the water-soluble solvent is, for example, 0.5% by mass to 15.0% by mass, and preferably 1.0% by mass to 8.0% by mass with respect to the total amount of ink of each color.

(Surfactant)
As the surfactant, a silicon-based surfactant and an acetylene glycol-based surfactant are preferable.
The silicon-based surfactant has an action of spreading uniformly so as not to cause ink printing unevenness and bleeding on the recording medium. The content of the silicon surfactant is preferably 0.1% by mass to 1.5% by mass with respect to the total amount of ink of each color. When the content of the silicon-based surfactant is less than 0.1% by mass, the ink is difficult to uniformly spread on the recording medium, so that ink printing unevenness and bleeding are likely to occur. On the other hand, when the content of the silicon surfactant exceeds 1.5% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.
The acetylene glycol-based surfactant is superior to other surfactants in that it has an excellent ability to maintain surface tension and interfacial tension, and has almost no foaming property. As a result, the color ink containing the acetylene glycol surfactant can appropriately maintain the surface tension and the interface tension with the printer member in contact with the ink such as the head nozzle surface, and this is applied to the ink jet recording method. In this case, the discharge stability can be improved. In addition, since the color ink containing an acetylene glycol surfactant exhibits good wettability and penetrability with respect to the recording medium, it is possible to obtain a high-definition image with less ink printing unevenness and bleeding. The content of the acetylene glycol surfactant is preferably 0.05% by mass to 1.0% by mass with respect to the total amount of each color ink. When the content of the acetylene glycol-based surfactant is less than 0.05% by mass, the ink is difficult to uniformly spread on the recording medium, so that ink printing unevenness and bleeding are likely to occur. On the other hand, when the content of the acetylene glycol surfactant exceeds 1.0% by mass, the storage stability and ejection stability of the color ink may not be ensured.

  As the silicon-based surfactant, a polysiloxane compound or the like is preferably used, and examples thereof include polyether-modified organosiloxane. For example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348 (above trade name, manufactured by Big 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 (above trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned, and BYK-348 is preferable.

  Examples of acetylene glycol surfactants include Surfinol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61. 82, DF37, DF110D, CT111, CT121, CT131, CT136, TG, GA (all trade names, manufactured by Air Products and Chemicals, Inc.), Olphin 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 trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all trade names, Surfenol 104PG-50 and DF110D having a hydrophobic tendency are particularly preferable from the viewpoint of improving wettability to non-absorbent recording media such as plastic films.

  Particularly preferred is a combination containing a silicon surfactant and an acetylene glycol surfactant at the same time.

  It is preferable that the surface tension of the water-based ink is used in the range of 23.0 mN / m to 40.0 mN / m, more preferably 25.0 mN / m to 35.0 mN by combining the above water-soluble solvent and the surfactant. / M range.

(water)
Water is the main medium of water-based ink, and preferable water is pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, distilled water, or the like for the purpose of reducing ionic impurities as much as possible. Ultrapure water can be used. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because it can prevent generation of mold and bacteria when the pigment dispersion and aqueous ink using the same are stored for a long period of time. .

(Other components of color ink)
Further, as necessary, moisturizers, preservatives and fungicides, pH adjusters, dissolution aids, antioxidants, metal trapping agents and the like can be mentioned.

  As the humectant, those which do not remain in the coating film upon drying are preferable. Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol, 2,3 -Butanediol etc. are mentioned.

  Examples of preservatives and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN from ICI) and the like.

  Examples of the pH adjuster include inorganic alkalis such as sodium hydroxide and potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, morpholine, potassium dihydrogen phosphate or disodium hydrogen phosphate.

  Examples of the solubilizer include allohanates such as urea, thiourea, dimethylurea, tetraethylurea, allophanate, and methyl allophanate, and biurets such as biuret, dimethylbiuret, and tetramethylbiuret.

  Examples of the metal trapping agent include ethylenediaminetetraacetic acid disodium.

[Resin ink]
The resin ink contains thermoplastic resin particles that are insoluble in a water-soluble resin solvent and water but are compatible with the water-soluble resin solvent. Thermoplastic resin particles that are insoluble in water and compatible with the water-soluble resin solvent described below are insoluble in water, but compatible with the water-soluble resin solvent that is added to the resin ink at the same time. It is a resin emulsion that is dissolved and stably dispersed in water. The term “compatible” refers to a combination that dissolves or swells when resin particles are mixed in a resin solvent. By the compatibility, a strong resin film can be formed after the resin ink is dried, and the film can be formed at a temperature lower than the original glass transition temperature of the resin particles. By using unnecessary resin particles in water, it is possible to keep the viscosity of each ink low while adding a sufficient amount of resin components in the resin ink, and to ensure ejection stability in high-speed printing. preferable.

  Moreover, it is preferable that a resin particle contains the resin particle A whose glass transition temperature is 20 degrees C or less, and the wax particle B from a viewpoint of abrasion resistance improvement. Since the resin particles A having a glass transition temperature of 20 ° C. or lower are softened at room temperature (25 ° C.), they have good adhesion to non-ink-absorbing or low-absorbing recording media and water-insoluble colorants. By forming the resin film while wrapping the colorant, the adhesion of the printed film after printing is improved. On the other hand, the wax particles B are also present on the surface of the resin film and have a characteristic of reducing the frictional resistance on the surface of the printed film. By the action of the resin particles A and the wax particles B, it is possible to form a resin film that is hard to be scraped off from the outside and hard to peel off from the recording medium. As a result, it is possible to improve the abrasion resistance.

  Furthermore, the resin particle content in the resin ink is preferably equal to or higher than the colorant content in the color ink as the ink set. If a resin ink containing resin particles having a colorant content equal to or higher than that of the color ink is used, a sufficient amount of resin particles can be adhered to the printing portion even in high-speed printing such as one-pass printing. Abrasion resistance can be realized, which is preferable. As a specific example, in the case of an ink set of black ink and resin ink containing 4% by mass of a colorant as color ink, the resin ink contains 4% by mass or more of resin particles.

  In addition, since it may be difficult to print over a resin ink (overcoat liquid) as a color ink overcoat on a non-ink-absorbing or low-ink-absorbing recording medium, By setting the resin particle content in the resin ink and the colorant content in the color ink in advance as in the ink set, an excellent scratching effect can be obtained even with a limited ink adhesion amount.

  It is preferable that the resin particle A is a resin particle emulsion obtained by emulsion polymerization of an unsaturated monomer. The reason is that, even if the resin particles are added to the ink composition as they are, dispersion of the resin particles may be insufficient, so that the emulsion form is preferable for the production of the ink composition. The emulsion is preferably an acrylic emulsion from the viewpoint of storage stability of the ink composition.

  The wax particles B are preferably polyethylene wax having a melting point of 90 to 150 ° C. If polyethylene wax having a melting point in this range is used, the slip effect of the resin film is further improved and the effect of excellent abrasion resistance is exhibited. When the melting point exceeds 150 ° C., the friction coefficient may be increased to reduce the slip property. When the melting point is lower than 90 ° C., the combined use with the resin particles A may reduce the expression of the slip effect due to the wax particles and may not improve the abrasion resistance.

  The content cost of the resin particles A and the wax particles B in the resin ink is preferably in the range of 1: 1 to 10: 1. If it is within this range, the above-described mechanism works well, and the printed material has good abrasion resistance.

  As with the color ink, the resin ink more preferably contains a silicon surfactant and an acetylene glycol surfactant. By using a combination of a silicon surfactant and an acetylene glycol surfactant, the ink can be similarly wetted to a wide range of recording media from non-absorbing to low-absorbing, and a printed matter with less printing unevenness can be obtained. Can do.

  Next, each component of the resin ink will be described in detail.

(Water-soluble resin solvent)
The water-soluble resin solvent is selected from water-soluble solvents that are compatible with the resin particles added simultaneously to the resin ink. There are optimum combinations depending on the resin to be used. Specifically, pyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone and 2-pyrrolidone, dimethyl sulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol isopropyl ether , Propylene glycol monomethyl ether, propylene glycol dimethyl ether Dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 1,4-dioxane and the like are preferable. In particular, pyrrolidones, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and the like are particularly preferable in terms of storage stability of resin ink, sufficient drying speed, and promotion of film formation of resin particles.

  Although the water-soluble resin solvent is added to the resin ink, there is no problem even if it is added to the color ink, and it is effective for strengthening the film formed by the resin particles.

  The addition amount of the water-soluble resin solvent is preferably 1.0% by mass to 20.0% by mass, and more preferably 2.0% by mass to 15.0% by mass with respect to the total amount of the resin ink. When the addition amount of the water-soluble resin solvent is less than 1% by mass, the formation of a film of resin particles in the resin ink may be hindered, resulting in insufficient solidification and fixing of the resin ink. On the other hand, when the addition amount of the water-soluble resin solvent exceeds 20% by mass, the storage stability of the resin ink may be deteriorated.

(Resin particles A having a glass transition temperature of 20 ° C. or less)
The glass transition point (Tg) of the resin particle A is 20 ° C. or lower, but is preferably 20 ° C. or lower and −50 ° C. or higher in order to effectively exhibit the effect of improving the abrasion resistance.

  In the present invention, the glass transition point (Tg) can be measured using a usual method, for example, a thermal analyzer such as a differential scanning calorimeter (DSC). An example of the thermal analyzer is SSC5000 manufactured by Seiko Electronics. The glass transition point (Tg) can be evaluated as a calculated value of the glass transition point when the resin is a copolymer. The glass transition point (Tg) of the copolymer and the methodology for its evaluation are as follows. The glass transition point (Tg) of a copolymer having a specific monomer composition can be determined by calculation using the Fox equation. Here, the Fox formula is for calculating the Tg of the copolymer based on the Tg of the homopolymer of the monomer for each monomer forming the copolymer, For example, JP-A-2005-330361, WO2004 / 029164 and the like can be referred to.

  Examples of the resin that can be applied to the resin particle A include, but are not limited to, an acrylic resin, a urethane resin, an epoxy resin, and a polyolefin resin. These resins are used singly or in combination when used, and may be a resin of the same system or a combination of different systems, but an emulsion of resin particles obtained by emulsion polymerization of unsaturated monomers It is preferably blended in the resin ink in the form of (for example, so-called “acrylic emulsion”). The reason for this is that the resin particles may be insufficiently dispersed even if they are added to the resin ink as they are, so that the emulsion form is preferable for the production of the resin ink. The emulsion is preferably an acrylic emulsion and more preferably a styrene-acrylic acid copolymer emulsion from the viewpoint of the storage stability of the resin ink.

  An emulsion of resin particles (such as an acrylic emulsion) can be obtained by a known emulsion polymerization method. For example, it can be obtained by emulsion polymerization of an unsaturated monomer (such as an unsaturated vinyl monomer) in water containing a polymerization initiator and a surfactant.

  Examples of unsaturated monomers include acrylic acid ester monomers, methacrylic acid ester monomers, aromatic vinyl monomers, vinyl ester monomers, vinyl cyanide compounds generally used in emulsion polymerization. Examples include monomers, halogenated monomers, olefin monomers, and diene monomers. Further, specific examples include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, decyl acrylate, dodecyl acrylate. Acrylates such as octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl Methacrylate, 2-ethyl Hexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, methacrylic esters such as phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate, and vinyl esters such as vinyl acetate; vinyl such as acrylonitrile and methacrylonitrile Cyanides; halogenated monomers such as vinylidene chloride and vinyl chloride; simple aromatic vinyl such as styrene, α-methylstyrene, vinyltoluene, 4-t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene Olefins such as ethylene and propylene; dienes such as butadiene and chloroprene; vinyl ether, vinyl ketone, vinyl pyrrolide Vinyl monomers such as ethylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid; acrylamides such as acrylamide, methacrylamide and N, N′-dimethylacrylamide; 2-hydroxy Examples thereof include hydroxyl group-containing monomers such as ethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate, and these can be used alone or in combination of two or more.

  A crosslinkable monomer having two or more polymerizable double bonds can also be used. Examples of the crosslinkable monomer having two or more polymerizable double bonds include polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4-acryloxypropyloxyphenyl) propane, 2,2 ′ -Diacrylate compounds such as bis (4-acryloxydiethoxyphenyl) propane, triacrylate compounds such as trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate , Tetraacrylate compounds such as ditrimethylol tetraacrylate, tetramethylol methane tetraacrylate, pentaerythritol tetraacrylate, hexaacrylate compounds such as dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol Dimethacrylate, , 2′-bis (4-methacryloxydiethoxyphenyl) propane and other dimethacrylate compounds, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate and other trimethacrylate compounds, methylenebisacrylamide, divinylbenzene and the like. Can be used alone or in admixture of two or more.

  In addition to the polymerization initiator and surfactant used in emulsion polymerization, a chain transfer agent, further a neutralizing agent, and the like may be used according to a conventional method. In particular, ammonia and inorganic alkali hydroxides such as sodium hydroxide and potassium hydroxide are preferred as the neutralizing agent.

  The resin particles A may be mixed with other components of the resin ink as fine particle powder. Preferably, the resin particles are dispersed in an aqueous medium to form an emulsion (polymer emulsion), and then the other components of the resin ink are used. It is preferable to be mixed with.

  The content of the resin particles A in the resin ink liquid is preferably 0.5% by mass to 15% by mass, and more preferably 1% by mass to 10% by mass.

  The preferable range of the content of these resin particles A defines the upper limit value from the viewpoint of the ink jet proper physical property value and the reliability (clogging, ejection stability, etc.) of the resin ink, and the effect (rubbing resistance, etc.) of the present invention. The lower limit is defined from the viewpoint of more effectively obtaining.

  The resin particles A preferably have an average particle diameter of 50 nm to 250 nm, particularly 60 nm to 200 nm, from the viewpoint of dispersion stability in the resin ink.

  Moreover, as the resin particle A, any of a single phase structure and a multiphase structure (core-shell type) can be used.

  The resin particles A are preferably blended as an emulsion from the viewpoint that they can be uniformly dispersed and prepared in the resin ink and storage stability.

  In the present invention, the term “resin particles” refers to particles in which a water-insoluble resin is dispersed in the form of particles in a dispersion medium mainly composed of water, or the water-insoluble resin is particles in a dispersion medium mainly composed of water. It means that which is dispersed in a shape, and further includes the dried product.

  In the present invention, the term “emulsion” means a solid / liquid dispersion called dispersion, latex or suspension.

  The emulsion is preferably nonionic from the viewpoint of improving the storage stability of the resin ink.

(Wax particles B)
Examples of components constituting the wax particles B include plant and animal waxes such as carnauba wax, candeli wax, beeswax, rice wax, and lanolin; petroleum oils such as paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, and petrolatum. Waxes; mineral waxes such as montan wax and ozokerite; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, stearamide, and natural and synthetic wax emulsions such as α-olefin / maleic anhydride copolymers and blends Wax or the like can be used alone or in combination. Among these, preferred types of wax are polyolefin wax, particularly polyethylene wax and polypropylene wax, and polyethylene wax is more preferable from the viewpoint of abrasion resistance against a non-ink-absorbing or low-absorbing recording medium. As the wax particles, commercially available products can be used as they are. For example, Nopcoat PEM17 (trade name, manufactured by San Nopco Co., Ltd.), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals), AQUACER 515 (trade name, Big Chemie Japan Co., Ltd.) Company-made).
Furthermore, the wax particles B are preferably polyethylene wax having a melting point of 90 to 150 ° C. If polyethylene wax having a melting point in this range is used, the slip effect of the resin film is further improved and the effect of excellent abrasion resistance is exhibited. When the melting point exceeds 150 ° C., the friction coefficient may be increased to reduce the slip property. When the melting point is lower than 90 ° C., the combined use with the resin particles A may reduce the expression of the slip effect due to the wax particles and may not improve the abrasion resistance.

  The average particle diameter of the wax particles B is preferably in the range of 5 nm to 400 nm, more preferably in the range of 50 nm to 200 nm, from the viewpoint of ensuring the storage stability and ejection stability of the aqueous ink composition.

  The content of the wax particles B is preferably 0.1% by mass to 10% by mass and more preferably 0.2% by mass to 6% by mass in terms of solid content with respect to the total amount of the aqueous ink composition. By being within this range, the aqueous ink composition used in the printing method according to the present embodiment can be solidified and fixed even on a non-ink-absorbing or low-absorbing recording medium. When the content is less than 0.1% by mass, the ink solidification / fixing strength is weakened, and it may be easily peeled off from the surface of the recording medium. On the other hand, when the content exceeds 10% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.

The reason why the printed material has good abrasion resistance when the above-described resin particles A and wax particles B are used in combination as resin particles is not yet clear, but is presumed as follows. Since the resin particles A have a good affinity for the non-ink-absorbing or low-absorbing recording medium and the water-insoluble colorant, the resin particles A are encapsulated when forming the resin film in the second step. Firmly fixed on the recording medium. On the other hand, the wax particles B are also present on the surface of the resin film, and have a characteristic of reducing the frictional resistance on the surface of the resin film. Thereby, it is presumed that the abrasion resistance of the printed matter is improved because it is possible to form a resin film that is hard to be scraped off from the outside and hardly peeled off from the recording medium.
The content ratio of the resin particles A and the wax particles B in the resin particles is preferably in the range of resin particles A: wax particles B = 1: 1 to 10: 1 in terms of solid content. If it is within this range, the above-described mechanism works well, and the printed material has good abrasion resistance.

(Other components of resin ink)
As described above, the resin ink preferably contains a silicon-based surfactant and an acetylene glycol-based surfactant. For these components, the same materials as those described for the color ink are employed. The content of the silicon surfactant is preferably 0.1% by mass to 1.5% by mass with respect to the total amount of ink of each color, and the content of the acetylene glycol surfactant is the ink of each color. Preferably they are 0.05 mass%-1.0 mass% with respect to the whole quantity. These addition amounts can be appropriately adjusted according to the type of recording medium and ink.

  The resin ink contains water as a main medium, similarly to the color ink. Further, as necessary, moisturizers, preservatives and fungicides, pH adjusters, dissolution aids, antioxidants, metal trapping agents and the like can be mentioned. For these materials, the same materials as those described for the color ink can be applied.

[Printing method]
The printing method according to the present embodiment includes a step of printing color ink and resin ink on a recording medium using an ink jet recording method.

  The order in which the color ink and the resin ink are applied to the recording medium may be any one, that is, the color ink and the resin ink are printed before printing, at the same time during printing, or after printing. The method of printing the resin ink before printing the color ink can increase the adhesion of the color ink to a polyolefin-based film such as polyethylene and polypropylene which are particularly non-ink-absorbing and difficult to wet. The method of printing resin ink simultaneously with color ink or after printing increases the ratio of the fixing resin to the colorant contained in the color ink by adding resin to the color ink, thereby increasing the abrasion resistance of the printing surface. be able to. However, the method of attaching the color ink to the recording medium and then attaching the resin ink to the recording medium is more preferable from the viewpoint of improving the abrasion resistance.

  By using the ink jet recording method, the resin ink can be selectively attached only to the place where the color ink is attached, and the consumption amount of the resin ink can be minimized. In addition, when a large amount of resin ink adheres to the entire paper surface, curling observed after drying can be suppressed.

  Further, the method of recording the color ink and the resin ink on the recording medium may be multipass or single pass, but it is preferable to record in one pass or two passes from the viewpoint of high-speed printing. Here, one pass is a recording method in which all dots to be formed in the scanning area are recorded by one scanning of the recording head. That is, the color ink and the resin ink are printed in one pass means that the color ink and the resin ink dots to be recorded in the recording head scanning area complete the recording by one recording head scanning. It is. The two-pass is a method of recording dots to be recorded in the recording head scanning area by two recording head scans. Further, in the one-pass recording method, after the recording head is scanned once in the main scanning direction to record dots, the entire image is formed by repeatedly moving the recording medium by the recording area in the sub-scanning direction. And a method of forming an image by fixing the recording head and scanning the recording medium, and any of them can be suitably used. High-speed printing is possible by recording in one pass or two passes, and the productivity of recorded matter is increased.

  For example, the print resolution for each color is 360 dpi (dot per inch) or more, the resolution ratio of the inkjet nozzle to the print resolution is in the range of 1 to 2 times, and the ink viscosity is 1.5 mPa · s to 15 mPa · s (20 ° C). In order to obtain high image quality, a high printing resolution of 360 dpi or higher is desirable, and if the resolution ratio of the inkjet nozzle to the printing resolution is in the range of 1 to 2 times, printing can be performed at high speed. In order to supply ink stably, the ink viscosity is preferably 1.5 mPa · s to 15 mPa · s (20 ° C.). For example, in the case of a nozzle resolution of 360 dpi, the above-described requirements are preferable when printing at 360 dpi to 720 dpi.

  In the high-speed printing as described above, the ink viscosity is preferably low. In the present embodiment, by separating the color ink and the resin ink, the viscosity of each ink is kept low while adding a sufficient amount of colorant in the color ink and a sufficient amount of resin component in the resin ink. And discharge stability can be ensured in high-speed printing.

  For example, the viscosity of the resin ink and ink composition at 20 ° C. is preferably in the range of 1.5 mPa · s to 15 mPa · s, and more preferably in the range of 1.5 mPa · s to 10 mPa · s. Preferably, the resin ink and the ink composition have substantially the same viscosity. For example, one viscosity is set to 50% to 200% of the other viscosity. Accordingly, when both the resin ink and the ink composition are ejected from the ink jet recording head, it is advantageous in that the recording head, the flow path structure, and the drive circuit can be made the same.

The printing method according to the present embodiment preferably includes a drying step during printing and / or after printing. By adding a drying process, evaporation of liquid media (specifically, water and water-soluble solvents) in color inks and resin inks is promoted, resulting in high-quality images with little printing unevenness and bleeding and abrasion resistance. A recorded matter can be obtained in a short time, wrinkling of the recording medium can be prevented, and curling of the recording medium can be effectively prevented.
Furthermore, the heating during drying promotes the fusion of the resin particles contained in the color ink and the resin ink, and it is possible to form an excellent film, thereby further improving the abrasion resistance of the recorded matter. The heating temperature is not particularly limited as long as the liquid medium present in the color ink and the resin ink can evaporate and a film of the resin agent can be formed. About 150 degreeC is preferable, More preferably, it is about 40 degreeC-80 degreeC. When the temperature exceeds 100 ° C., the recording medium may be deformed or the like, resulting in trouble in conveyance.
The drying / heating time is not particularly limited as long as the liquid medium present in the color ink and the resin ink evaporates and a film of the resin agent can be formed. The liquid medium type, resin type, and printing speed to be used are not limited. It can be set appropriately taking into account.
The drying method is not particularly limited as long as it is a method for promoting the volatilization of the liquid medium contained in the color ink and the resin ink. Examples thereof include a method of applying heat to the recording medium before and after printing, a method of blowing air on the recording medium after printing, and a method of combining them. Specific examples include forced air heating, radiation heating, conduction heating, high frequency drying, microwave drying, and dry air blowing.

(Example)
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Color ink)
Each constituent component was blended in the blending amounts shown in Table 1 (mass% of each component with respect to the total mass of the color ink) to obtain A1 to A24 as color inks.

(Resin ink)
Moreover, each component was mix | blended with the compounding quantity shown in Table 2 (mass% of each component with respect to the total mass of the resin ink), and resin ink B1-B17 was obtained.

(Ink set)
Then, ink sets including various color inks and resin inks were prepared and printed by the ink jet method under the conditions shown in Tables 3 and 4. Cold recording film PG-50L (trade name, manufactured by Lamy Corporation) of PET media as a non-absorbable recording medium that is printed on two types of recording media and the recording surface is a plastic film, low-absorbency recording As a medium, an OK top coat + (trade name, manufactured by Oji Paper Co., Ltd.) of glossy fine coated paper used as so-called printing paper was used. Using an ink jet printer PX-930 (trade name, manufactured by Seiko Epson Corporation, nozzle resolution 180 dpi) with a heater attached to the paper guide and adjusted to 40 ° C., using the ink set shown in Table 3 at a printing resolution of 360 dpi Printed patches and images.

(Printing process)
In the examples and comparative examples shown in Tables 3 and 4, one of the following printing processes was employed.
Printing process 1: Printing method for printing resin ink after printing color ink Printing process 2: Printing method for printing color ink and resin ink in the same pass simultaneously Printing process 3: Printing color ink after printing resin ink Printing method

(Drying process)
In the examples and comparative examples shown in Table 3 and Table 4, any of the drying steps shown below was employed.
Drying process a: After the printing process is completed, the printed matter is left in a dryer at 50 ° C. for 10 minutes to dry. Drying step B: After printing one of the color ink or the resin ink, the printed matter is put into a dryer at 50 ° C. After drying for a minute, print with the remaining ink, and then leave the printed matter in a dryer at 50 ° C. for 8 minutes to dry.

  The following evaluation was performed about the obtained recorded matter. Tables 3 and 4 show the results of the evaluation.

(Evaluation 1: Color gamut)
A color chart composed of color 384 patches was printed, L ^* a ^* b ^* color space volume (gamut value) was calculated using Spectrolino (manufactured by Gretag Macbeth), and evaluated according to the following criteria. The resin ink was printed with the same duty as the color ink.
A: Gamut value is 400,000 or more B: Gamut value is less than 400,000

(Evaluation 2: Print quality)
A patch pattern having a duty of 40% to 100% was created in 10% increments so that different color inks were in contact with each other, and bleeding and uneven printing of the printed matter were visually observed and evaluated according to the following criteria. . The resin ink was printed with the same duty as the color ink.
A: No bleeding or printing unevenness was confirmed even at a duty of 70% or more. B: No bleeding or printing unevenness was confirmed at a duty of 60%. C: No bleeding or printing unevenness was confirmed at a duty of 50%. D: Bleeding even at a duty of 40% or less. And printing unevenness

(Evaluation 3: Abrasion resistance)
A patch was prepared for each color ink under the conditions of 60% duty of color ink and 60% duty of resin ink, and peeling of the printed part due to rubbing the printed part with a nail was visually observed. The evaluation criteria are as follows.
A: There is almost no peeling of the printed part even when rubbed strongly B: Some peeling of the printed part occurs slightly when rubbed strongly C: Some peeling of the printed part occurs when rubbed D: Peeling of the printed part is practical when rubbed It is a level that is a problem

(Evaluation 4: Discharge stability)
As for the ejection stability of each ink of Examples 1 to 16, it was confirmed that there were no ejection defects such as clogging and flight bending during printing of the color chart of Evaluation 1, and there was no practical problem.

  The present invention relates to a printing method in which an image is formed on an ink non-absorbing and low-absorbing recording medium by an ink jet recording method, and high-speed printing is possible. In addition, the present invention has industrial applicability for a printing method using an ink jet recording method that is excellent in discharge stability.

Claims (5)

A printing method of printing an image by applying a color ink and a resin ink to a non-ink-absorbing or low-absorbing recording medium by an ink jet recording method using a water-based ink set,
(1) The water-based ink set includes the color ink containing a colorant and the resin ink containing resin particles without containing a colorant,
(2) The color ink includes at least a water-insoluble colorant, a water-soluble and / or water-insoluble resin component, a water-soluble solvent, and a surfactant.
(3) The resin ink includes a water-soluble resin solvent, thermoplastic resin particles that are insoluble in water but compatible with the water-soluble resin solvent, and the resin particles have a glass transition temperature of 20 ° C. or less. The resin particles A and the wax particles B, and the resin particle content in the resin ink is equal to or higher than the colorant content in the color ink,
(4) only contains the Drying process during printing,
The resin particles A are at least one selected from the group consisting of acrylic resins, urethane resins, and epoxy resins,
The wax particles B are carnauba wax, candeli wax, beeswax, rice wax, lanolin, paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, petrolatum, montan wax, ozokerite, carbon wax, Hoechst wax, polyolefin wax, One or more selected from the group consisting of stearamide, α-olefin / maleic anhydride copolymer,
The content ratio of the resin particles A and the wax particles B is 1: 1 to 10: 1.
The drying step is performed by a method of heating the recording medium, and the heating temperature is 40 ° C to 100 ° C.
An ink jet recording method printing method.   The printing method according to claim 1, wherein the color ink further includes a special color in addition to the process color, and the special color includes orange and green.   The printing method according to claim 1, wherein the resin particles A are resin particle emulsions obtained by emulsion polymerization of unsaturated monomers.   The printing method according to any one of claims 1 to 3, wherein the wax particles B are polyethylene wax having a melting point of 90 to 150 ° C.   The printing method according to any one of claims 1 to 4, wherein the color ink and the resin ink contain a silicon-based surfactant and an acetylene glycol-based surfactant.