JP2011194818A - Method for printing by inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for printing capable of forming an image with an excellent printing quality on a recording medium by using an inkjet recording method.SOLUTION: The method for printing by the inkjet recording method is such a method for printing that uses the inkjet recording method, and includes: a first process in which liquid droplets of an aqueous ink composition are delivered on the recording medium to form the image; and a second process in which on at least one of a process during the first process and a process after the first process, the aqueous ink composition on the recording medium is dried. The aqueous ink composition is characterized by comprising at least a water-insoluble coloring agent, glycol ethers with a HLB value calculated by the Davis method within a range of 4.2-8.0, 1,2-alkyl diols with a carbon number within a range of 4-8, and water.

Description

  The present invention relates to a printing method using an inkjet recording method.

  A printing method using an ink jet recording method is performed by causing ink droplets to fly and adhere to a recording medium such as paper. Due to recent advances in ink-jet recording technology, printing methods using ink-jet recording are now being used in the field of high-definition image recording (image printing), which previously used photographs and offset printing. It has become. For this reason, high-quality printed materials can be found not only on commonly used plain paper and special paper for inkjet recording (matte and glossy) but also on non-ink-absorbing or low-absorbing recording media such as printing paper, synthetic paper, and films. It has been demanded.

  Various proposals have heretofore been made for ink compositions capable of obtaining high-quality images on plain paper, inkjet recording paper, etc. Specifically, pigments coated with a water-insoluble polymer, specific An ink composition comprising at least glycol ethers and 1,2-alkyldiols has been proposed (see Patent Document 1).

  In recent years, water-based inks have been used from the viewpoint of safety and environmental protection in place of solvent-based pigment inks that have been used for film-based recording media such as polyvinyl chloride-based substrates, that is, non-ink-absorbing recording media. It has come to be used. Specific examples of such water-based inks include water, glycol solvents, insoluble colorants, polymer dispersants, silicone surfactants, fluorinated surfactants, water-insoluble graft copolymer binders, and N-methylpyrrolidone. There has been proposed a method of printing on a hydrophobic surface using the contained ink (see Patent Document 2). In addition, aqueous colloid-containing aqueous inkjet inks have been proposed for printing on non-porous substrates consisting of an aqueous liquid vehicle containing a volatile cosolvent having a boiling point of 285 ° C. or lower, acid functionalized polymer colloid particles, and a pigment colorant. (See Patent Document 3).

  However, the conventionally proposed water-based ink and the printing method using the same cannot be said to be sufficiently excellent in the print quality of the image formed on the recording medium. There has been a demand for a printing method using this. Specifically, color mixing between different colors or a phenomenon that spreads beyond the desired area (hereinafter referred to as “bleed”) occurs, or the ink is dark and light in the filled image. The phenomenon (hereinafter referred to as “light / dark unevenness”) occurs, and the conventional ink composition and the printing method using the conventional ink composition did not provide the desired print quality.

JP 2009-235155 A JP 2000-44858 A JP 2005-220352 A

  An object of the present invention is to provide a printing method for forming an image on a recording medium by an ink jet recording method, and to provide a printing method of an ink jet recording method capable of obtaining a printed matter with less blur and uneven shading. To do. In particular, an object of the present invention is to provide a printing method of an ink jet recording method capable of obtaining a printed matter having excellent print quality with little blurring and shading unevenness even on a non-ink-absorbing or low-absorbing recording medium. .

  The inkjet recording method printing method according to the present invention is an inkjet recording method in which a first step of forming an image by ejecting droplets of a water-based ink composition on a recording medium, the first step, and the first step And a second step of drying the water-based ink composition on the recording medium at least one after the step 1, the water-based ink composition comprising at least a water-insoluble colorant and , Glycol ethers having an HLB value calculated by the Davis method in the range of 4.2 to 8.0, 1,2-alkyldiols having a carbon number of 4 to 8 and water. It is characterized by becoming.

  In addition, the inkjet recording method printing method according to the present invention is preferably characterized in that the alkyl group of the glycol ether has a branched structure.

  The inkjet recording method printing method according to the present invention is preferably characterized in that the glycol ethers are contained in the range of 0.1% by mass to 6% by mass with respect to the total amount of the aqueous ink composition.

  The inkjet recording method printing method according to the present invention is preferably characterized in that the 1,2-alkyldiols are contained in a mass ratio of 0.5 to 5 times with respect to the glycol ethers. And

  The inkjet recording method printing method according to the present invention is preferably characterized in that the 1,2-alkyldiols are contained in a range of 0.5% by mass to 20% by mass with respect to the aqueous ink composition. To do.

  Also, the printing method of the ink jet recording system according to the present invention is preferably characterized in that the alkyl group of the glycol ethers is a 2-ethylhexyl group.

  In addition, the ink jet recording printing method according to the present invention is preferably characterized in that it further contains a nonionic surfactant.

  In the inkjet recording method according to the present invention, the nonionic surfactant is preferably a silicone surfactant and / or an acetylene glycol surfactant.

  In addition, the printing method of the ink jet recording system according to the present invention is preferably characterized by further containing a pyrrolidone derivative.

  In addition, the ink jet recording type printing method according to the present invention is preferably characterized in that it further contains a polyhydric alcohol.

  In addition, the printing method of the ink jet recording system according to the present invention is preferably characterized by further containing a pyrrolidone resin derivative.

  In addition, the printing method of the ink jet recording system according to the present invention is preferably characterized by further containing resin particles.

  The inkjet recording method printing method according to the present invention is preferably characterized by using a non-ink-absorbing or low-absorbing recording medium as the recording medium.

  In the inkjet recording method printing method according to the present invention, preferably, in any one of the preceding paragraphs, the second step includes a step of heating the recording medium to 40 ° C. to 80 ° C. and the aqueous solution on the recording medium. It includes at least one of a step of blowing air at 40 ° C. to 80 ° C. to the ink composition.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

1. Inkjet Recording Method Printing Method An inkjet recording method printing method according to the present embodiment is an inkjet recording method, wherein a first step of forming an image by discharging droplets of a water-based ink composition onto a recording medium; A second step of drying the water-based ink composition on the recording medium at least one of the first step and after the first step, wherein the water-based ink composition comprises: , At least a water-insoluble colorant, glycol ethers having an HLB value calculated by the Davis method in the range of 4.2 to 8.0, and 1,2-alkyl having a carbon number of 4 to 8 It comprises diols and water.
First, the water-based ink composition used in the inkjet recording method printing method according to the present embodiment will be described below.

1.1 Aqueous Ink Composition The aqueous ink composition used in the ink jet recording printing method according to the present invention has at least a water-insoluble colorant and an HLB value calculated by the Davis method of 4.2 to 8.0. It is characterized by comprising glycol ethers in the range, 1,2-alkyldiols having 4 to 8 carbon atoms, and water.
Further, the water-based ink composition used in the printing method according to the present invention is preferably a nonionic compound in addition to the above components in order to improve suitability for various recording media, particularly non-ink-absorbing or low-absorbing recording media. A surfactant, a pyrrolidone derivative, a pyrrolidone resin derivative, resin particles and / or polyhydric alcohols other than 1,2-alkyldiol having 4 to 8 carbon atoms are included.
Hereinafter, these constituent materials will be described in detail.

1.1.1 Colorant The water-based ink composition used in the printing method according to the present invention contains a water-insoluble colorant. Water-insoluble colorants include water-insoluble dyes or pigments, with pigments being preferred. The pigment is not only insoluble or hardly soluble in water but also has a property of hardly fading to light, gas, and the like. For this reason, a printed matter printed with an ink composition using a pigment is excellent in water resistance, gas resistance, light resistance, and the like, and has good storage stability.
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.

  In the present invention, specific examples of preferable 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). Note that these are examples of carbon black suitable for the present invention, and the present invention is not limited to these. These carbon blacks may be used alone or as a mixture of two or more. The content of these carbon blacks is 0.5% by mass to 20% by mass, preferably 1% by mass to 10% by mass with respect to the total amount of the black ink composition.

Preferred organic pigments in the present invention include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments. And diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments and azo pigments.
Specific examples of the organic pigment used in the water-based ink composition according to the present invention include the following.
Examples of the pigment used in the cyan ink composition include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, C.I. 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. The content of these pigments is about 0.5% to 20% by mass, preferably about 1% to 10% by mass, based on the total amount of the cyan ink composition.
Examples of the pigment used in the magenta ink composition include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, 209, C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, 209, and C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Violet 19. The content of these pigments is about 0.5% to 20% by mass, preferably about 1% to 10% by mass, based on the total amount of the magenta ink composition.
Examples of the pigment used in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 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. The content of these pigments is about 0.5% to 20% by mass, preferably about 1% to 10% by mass, based on the total amount of the yellow ink composition.
Examples of the pigment used in the orange ink composition include C.I. I. Pigment Orange 36 or 43, or a mixture thereof. The content of these pigments is about 0.5% to 20% by mass, preferably about 1% to 10% by mass, based on the total amount of the orange ink composition.
Examples of the pigment used in the green ink composition include C.I. I. Pigment Green 7 or 36 or a mixture thereof. The content of these pigments is about 0.5% to 20% by mass, preferably about 1% to 10% by mass, based on the total amount of the green ink composition.

  In order to apply the above pigment to an aqueous ink composition, it is necessary to enable the pigment to be stably dispersed and held in water. As the method, a method of dispersing with a resin dispersant such as a water-soluble resin and / or a water-dispersible resin (hereinafter, a pigment treated by this method is referred to as a “resin-dispersed pigment”), a water-soluble surfactant A method of dispersing with a surfactant of an agent and / or a water-dispersible surfactant (hereinafter, a pigment treated by this method is referred to as “surfactant-dispersed pigment”), and hydrophilic functional groups on the surface of pigment particles In which the pigment treated by this method can be dispersed and / or dissolved in water without a dispersant such as the above-mentioned resin or surfactant (hereinafter referred to as “surface-treated pigment”). And the like). As the water-based ink composition used in the printing method according to the present embodiment, any of the above resin-dispersed pigments, surfactant-dispersed pigments, and surface-treated pigments can be used. It can also be used.

  Examples of the resin dispersant used for the resin dispersion pigment include polyvinyl alcohols, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, and styrene. -Acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid- Acrylate ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-maleic acid ester copolymer Polymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic Examples include acid copolymers and salts thereof. Among these, a copolymer of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, and a polymer comprising a monomer having both a hydrophobic functional group and a hydrophilic functional group are particularly preferable. As the form of the copolymer, any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer can be used.

  Examples of the salt include basic compounds such as ammonia, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, triisopropanolamine, aminomethylpropanol, and morpholine. Of the salt. The addition amount of these basic compounds is not particularly limited as long as it is not less than the neutralization equivalent of the resin dispersant.

  The molecular weight of the resin dispersant is preferably in the range of 1,000 to 100,000 as the weight average molecular weight, and more preferably in the range of 3,000 to 10,000. When the molecular weight is in the above range, a stable dispersion of the colorant in water can be obtained, and viscosity control when applied to an aqueous ink composition is easy.

  Moreover, it is preferable that it is the range of 50-300 as an acid value, and it is more preferable that it is the range of 70-150. When the acid value is within this range, the dispersibility of the colorant particles in water can be stably secured, and the water resistance of the printed matter printed with the aqueous ink composition using the colorant particles is good.

  Commercially available products can be used as the resin dispersant described above. Specifically, Joncryl 67 (weight average molecular weight: 12,500, acid value: 213), Joncryl 678 (weight average molecular weight: 8,500, acid value: 215), Joncryl 586 (weight average molecular weight: 4,600) , Acid value: 108), joncryl 611 (weight average molecular weight: 8,100, acid value: 53), joncryl 680 (weight average molecular weight: 4,900, acid value: 215), joncryl 682 (weight average molecular weight) : 1,700, acid value: 238), joncryl 683 (weight average molecular weight: 8,000, acid value: 160), joncryl 690 (weight average molecular weight: 16,500, acid value: 240) , Manufactured by BASF Japan Ltd.).

  The surfactant used in the surfactant-dispersed pigment includes alkane sulfonate, α-olefin sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, acylmethyl taurate, and dialkyl sulfo oxalate. Anionic surfactants such as alkyl sulfate ester salts, sulfated olefins, polyoxyethylene alkyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, monoglycerite phosphate ester salts, Amphoteric surfactants such as alkyl pyridium salts, alkyl amino acid salts, alkyl dimethyl betaines, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylenes Alkylamide, glycerol alkyl esters, nonionic surfactants such as sorbitan alkyl esters.

  The amount of the resin dispersant or the surfactant added to the pigment is preferably 1 part by mass to 100 parts by mass, more preferably 5 parts by mass to 50 parts by mass with respect to 100 parts by mass of the pigment. By being in this range, the dispersion stability of the pigment in water can be ensured.

As the surface-treated pigment, as the hydrophilic functional group, -OM, -COOM, -CO -, - SO 3 M, -SO 2 NH 2, -RSO 2 M, -PO 3 HM, -PO 3 M 2 , —SO ₂ NHCOR, —NH ₃ , —NR ₃ (wherein M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and R represents an alkyl group having 1 to 12 carbon atoms or a substituent. An optionally substituted phenyl group or an optionally substituted naphthyl group.) And the like. These functional groups are physically and / or chemically introduced by grafting directly to the pigment particle surface and / or via multivalent groups. Examples of the polyvalent group include an alkylene group having 1 to 12 carbon atoms, a phenylene group which may have a substituent, or a naphthylene group which may have a substituent.

In addition, as the surface-treated pigment, -SO ₃ M and / or -RSO ₂ M (M is a counter ion, hydrogen ion, alkali metal ion, ammonium ion is added to the pigment particle surface by a treatment agent containing sulfur. Or an organic ammonium ion)) that has been surface-treated so as to chemically bond, that is, the pigment does not have an active proton, has no reactivity with sulfonic acid, and the pigment is insoluble or hardly soluble. In the solvent, the pigment is dispersed, and then the surface treatment is performed so that —SO ₃ M and / or —RSO ₂ M are chemically bonded to the particle surface by amidosulfuric acid or a complex of sulfur trioxide and tertiary amine. In addition, it is preferable that it can be dispersed and / or dissolved in water.

  Various known surface treatment means can be applied as the surface treatment means for grafting the functional group or a salt thereof directly on the surface of the pigment particles or via a polyvalent group. For example, means for treating a commercially available oxidized carbon black with ozone or a sodium hypochlorite solution to further oxidize the carbon black to make the surface more hydrophilic (for example, JP-A-7-258578, JP-A-H10-238707). 8-3498, JP-A-10-120958, JP-A-10-195331, JP-A-10-237349), means for treating carbon black with 3-amino-N-alkyl-substituted pyridium bromide ( For example, JP-A-10-195360 and JP-A-10-330665), an organic pigment is dispersed in a solvent in which the organic pigment is insoluble or hardly soluble, and a sulfone group is introduced onto the pigment particle surface by a sulfonating agent. Means (for example, JP-A-8-283596, JP-A-10-110110, JP-A-10-1101 No. 1), means for dispersing an organic pigment in a basic solvent that forms a complex with sulfur trioxide, treating the surface of the organic pigment by adding sulfur trioxide, and introducing a sulfone group or a sulfonamino group (For example, Unexamined-Japanese-Patent No. 10-110114) etc. are mentioned, However, The preparation means for the surface treatment pigment used by this invention is not limited to these means.

  The functional group grafted on one pigment particle may be single or plural kinds. The type and degree of the functional group to be grafted may be appropriately determined in consideration of the dispersion stability in the ink, the color density, the drying property on the front surface of the inkjet head, and the like.

  As a method for dispersing the above-described resin dispersed pigment, surfactant dispersed pigment, and surface-treated pigment in water, the pigment-dispersed pigment, water, and resin dispersant for the resin-dispersed pigment, and the pigment, water, and interface for the surfactant-dispersed pigment. For activators and surface-treated pigments, add surface-treated pigment and water, and water-soluble organic solvents / neutralizers, etc., if necessary. Ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid It can be carried out by a conventionally used disperser such as a mill, an ultrasonic homogenizer, a jet mill or an ang mill. In this case, the dispersion of the pigment in water is ensured by dispersing the pigment until the average particle size is in the range of 20 nm to 500 nm, more preferably in the range of 50 nm to 200 nm. This is preferable.

1.1.2 Glycol ethers The aqueous ink composition used in the printing method according to the present invention contains glycol ethers having an HLB value calculated by the Davis method in the range of 4.2 to 8.0. . By including the glycol ethers satisfying the above HLB value range in the aqueous ink composition, the aqueous ink composition can control wettability and penetration speed without being affected by the type of the recording medium, and can be used for various recording media. On the other hand, it is possible to obtain a clear printed image with little density unevenness, high color development and little blur. In addition, by combination with 1,2-alkyldiols (1,2-alkyldiols having a carbon number in the range of 4 to 8) having compatibility with glycol ethers described later, Since the affinity is improved and the dispersibility of the resin-dispersed pigment, surfactant-dispersed pigment, and surface-treated pigment described above is not adversely affected, the storage stability of the water-based ink composition is good, and the ink by the ink jet recording method is used. Excellent droplet ejection stability.

  Here, the HLB value of the glycol ethers used in the aqueous ink composition of the printing method according to the present invention is a value for evaluating the hydrophilicity of the compound proposed by Davis et al., For example, the document “JT Davies and E. K. Rideal, “Interface Phenomena” 2nd ed. Academic Press, New York 1963 ”, which is a numerical value obtained by the Davis method defined by the following equation (1).

(However, [1] represents the number of hydrophilic groups and [2] represents the number of hydrophobic groups).
Table 1 below exemplifies the number of representative hydrophilic groups and hydrophobic groups.

  The water-based ink composition used in the printing method according to the present invention comprises glycol ethers having an HLB value calculated by the Davis method of 4.2 to 8.0 as an essential component. The HLB value is preferably in the range of 4.2 to 8.0, more preferably in the range of 4.2 to 7.1. When the HLB value is less than 4.2, the hydrophobicity of the glycol ethers increases, and the affinity with water as the main solvent may decrease to deteriorate the ink storage stability. If the HLB value is greater than 8.0, the wettability / penetration effect on the recording medium is reduced, and the printed image may be affected by uneven density, blurring, and poor color developability. In particular, the wettability effect on a non-ink-absorbing or low-absorbing recording medium that is a hydrophobic surface is significantly reduced. Specific examples of the glycol ethers include ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol. Monoisohexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoisoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoiso Octyl ether, D Lenglycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono- 2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol monomethyl Examples include ether. These can be used 1 type or in mixture of 2 or more types.

  Furthermore, the aqueous ink composition used in the printing method according to the present invention preferably has a branched structure in the alkyl group of the glycol ethers. By including glycol ethers having a branched structure in the alkyl group, the water-based ink composition does not depend on the recording medium, particularly when printing on a non-ink-absorbing or low-absorbing recording medium. An excellent printed image with less color and high color development can be obtained. Specifically, ethylene glycol monoisobutyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol monoisohexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoiso Heptyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether , Diethylene glycol mono-2-ethyl Inch ether, ethylene glycol mono-2-ethyl pentyl ether, ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, and the like.

  In order to further improve the color developability, as the branched structure of the glycol ethers, the alkyl group is more preferably a 2-methylpentyl group, a 2-ethylpentyl group or a 2-ethylhexyl group, and a 2-ethylhexyl group. Is most preferred. Specifically, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-1-ethylpentyl ether, And ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, and the like. In particular, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl Ether and the like are preferable.

  The content of the glycol ethers is based on the total amount of the water-based ink composition from the viewpoint of high color developability, wettability improvement effect, bleeding reduction effect, density unevenness reduction effect, ink storage stability, and ejection reliability of the water-based ink composition. On the other hand, it is preferably contained in the range of 0.1% by mass to 6% by mass. If it is less than 0.1% by mass, the wetness, penetrability and drying of the water-based ink composition will be poor, and it will be difficult to obtain a clear image, and the printing density (color development) will be insufficient. There is a case. On the other hand, if it exceeds 6% by mass, the viscosity of the ink becomes high and it becomes difficult to discharge stably, or the solubility in the water-based ink composition cannot be obtained, and the stable storage stability for a long time may not be obtained. .

1.1.3 1,2- alkyldiols having 4 to 8 carbon atoms The water-based ink composition used in the printing method according to the present invention has 4 to 8 carbon atoms (hereinafter abbreviated as C4 to 8). 1,2-alkyldiols in the range of
C4-8 1,2-alkyldiols synergize with the above-mentioned glycol ethers to further increase the wettability of the water-based ink composition with respect to the recording medium and uniformly wet it, and to further increase the permeability. Have. Therefore, by adding C4-8 1,2-alkyldiols to the water-based ink composition, it is possible to further reduce ink density unevenness and bleeding. Further, C4-8 1,2-alkyldiols are excellent in compatibility with the above-mentioned glycol ethers. Here, “compatible” means that among the components constituting the water-based ink composition, the glycol ethers and C4-8 1,2-alkyldiols in the ink composition using water as the main solvent. It means the combination of each material and the ratio of each material such that the mixture is completely dissolved. By including a C4-8 1,2-alkyldiol having excellent compatibility with the glycol ethers in the aqueous ink composition, the solubility of the glycol ether in the aqueous ink composition can be increased, and the ink Improve storage stability and discharge stability. Moreover, since it becomes easy to increase the content of the glycol ethers in the aqueous ink composition, it is possible to contribute to further improvement in printing quality.

  Specific examples of C4-8 1,2-alkyldiols having such characteristics include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, and 1,2-heptanediol. 1,2-octanediol, 4-methyl-1,2-pentanediol, and the like. Among them, in particular, C6-C8 (C6-C8) 1,2-alkyldiols such as 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, etc. are dissolved in water. From the viewpoint of compatibility and compatibility with the glycol ethers.

  From the viewpoint of compatibility with the glycol ethers, the addition amount of C4-8 1,2-alkyldiols is in the range of 0.5 to 5 times by mass ratio with respect to the glycol ethers. It is preferable that the range is 2 to 5 times. In addition, from the viewpoint of compatibility with the glycol ethers and ensuring the storage stability and ejection stability of the aqueous ink composition, it is preferably in the range of 0.5% by mass to 20% by mass with respect to the total amount of the aqueous ink composition. More preferably, it is the range of 1 mass%-8 mass%. When the content of C4-8 1,2-alkyldiols is less than 0.5% by mass, the wetness of the water-based ink composition with respect to the recording medium is poor, and uneven density and blurring occur in the printed matter. There is a case. On the other hand, when the amount is more than 20% by mass, the viscosity of the water-based ink composition is difficult to be within an appropriate range in the ink jet recording method, and the discharge is likely to be unstable, or the storage stability of the water-based ink composition over a long period of time May be difficult to secure. If the second step (drying step) described later of the printing method in the present invention is more preferably in the range of 1% by mass to 8% by mass, evaporation of C4-8 1,2-alkyldiols is evaporated. Since the speed is sufficiently high, there is an extraordinary effect that the printed matter is dried quickly and the printing speed is improved. There is no problem in terms of odor during the printing process.

1.1.4 Water The aqueous ink composition of the present invention contains water. Water is a main medium of the water-based ink composition, and is a component that evaporates and scatters in a second step (drying step) described later.
The water is preferably water from which ionic impurities such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water are removed as much as possible. Use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because it can prevent the generation of mold and bacteria when the pigment dispersion and the aqueous ink composition using the same are stored for a long period of time. is there.

1.1.5 Other Preferred Components The water-based ink composition used in the printing method according to the present invention has an HLB value calculated by the water-insoluble colorant and Davis method described above in the range of 4.2 to 8.0. It contains at least glycol ethers, C4-8 1,2-alkyldiols, and water. With this configuration, the water-based ink composition can control wettability / penetration speed without being greatly affected by the type of recording medium, and has a clear color with less unevenness and high color development and less bleeding on various recording media. A printed image can be obtained. Further, the storage stability of the water-based ink composition is good, and the ejection stability of ink droplets by the ink jet recording method is excellent. In order to further improve these properties, various materials listed below are preferably added.

1.1.5.1 Nonionic surfactant The aqueous ink composition used in the printing method according to the present invention preferably contains a nonionic surfactant. The nonionic surfactant has an action of spreading the aqueous ink composition uniformly on the recording medium. Therefore, when an aqueous ink composition containing this is used, there is an effect that a clearer image can be obtained with less uneven density and blurring. Nonionic surfactants having such effects include polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polycyclic phenyl ethers, sorbitan derivatives, fluorines, silicones, acetylene glycols and the like. . Among these, particularly excellent in the above-described effects, and excellent in compatibility and synergistic effect between the glycol ethers essential for the aqueous ink composition of the present invention and the C4-8 1,2-alkyldiols, Silicone surfactants and acetylene glycol surfactants are preferred.

1.1.5.1.1 Silicone Surfactant The aqueous ink composition used in the printing method according to the present invention preferably contains a silicone surfactant. Silicone-based surfactants are superior to other nonionic surfactants in their ability to spread uniformly on the recording medium so as not to cause uneven density or bleeding of ink. Moreover, the synergistic effect of the compatibility and characteristics of the glycol ethers essential for the water-based ink composition of the invention and the C4-8 1,2-alkyldiols is excellent. The content of the silicone surfactant is preferably in the range of 1.5% by mass or less with respect to the total amount of the water-based ink composition. If the content of the silicone surfactant exceeds 1.5% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.
As the silicone surfactant, a polysiloxane compound or the like is preferably used, and examples thereof include polyether-modified organosiloxane. More specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (above trade names, 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 names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

1.1.5.1.2 Acetylene glycol surfactant The aqueous ink composition used in the printing method according to the present invention preferably contains an acetylene glycol surfactant. The acetylene glycol-based surfactant is superior to other nonionic surfactants in its ability to keep the surface tension and the interfacial tension properly, and has almost no foaming property. As a result, the aqueous ink composition containing the acetylene glycol surfactant can appropriately maintain the surface tension and the interfacial tension with the printer member in contact with the ink such as the head nozzle surface. When applied to the above, the discharge stability can be improved. In addition, the acetylene glycol-based surfactant acts as a good wetting and penetrating agent for the recording medium in the same manner as the glycol ethers and the C4-8 1,2-alkyldiols. However, the printed image with the water-based ink composition is a high-definition image with little unevenness of density and bleeding. The content of the acetylene glycol surfactant is preferably 1.0% by mass or less based on the total amount of the aqueous ink composition. If the content of the acetylene glycol surfactant exceeds 1.0% by mass, the storage stability and ejection stability of the aqueous ink composition may not be ensured.

  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, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (all trade names, manufactured by Air Products and Chemicals, Inc.), Olfin 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, Kawaken Fine Chemical Co., Ltd.).

1.1.5.2 Pyrrolidone derivative The aqueous ink composition used in the printing method according to the present invention preferably contains a pyrrolidone derivative. Pyrrolidone derivatives have the effect of acting as a good solubilizer or softener when resin particles described below are used. In addition, the pyrrolidone derivative promotes film formation by polymer particles, which are resin particles described below when the ink is dried, and solidifies the ink on a recording medium, particularly on a non-ink-absorbing or low-absorbing recording medium. Has the effect of promoting fixing. The content of the pyrrolidone derivative is preferably 10% by mass or less based on the total amount of the aqueous ink composition. When the content of the pyrrolidone derivative exceeds 10% by mass, the pyrrolidone derivative is insufficiently evaporated and scattered even after the second step (drying step) of the printing method according to the present invention described later. Insufficient drying may cause problems in terms of odor.

  Examples of pyrrolidone derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, 5-methyl-2-pyrrolidone, etc. These are low molecular compounds. Of these, 2-pyrrolidone is particularly preferred from the viewpoint of ensuring the storage stability of the water-based ink composition, the promotion of film formation of polymer particles, and the relatively low odor.

1.1.5.3 Polyhydric alcohols The aqueous ink composition used in the printing method according to the present invention preferably contains polyhydric alcohols. The polyhydric alcohols have an action of preventing clogging and ejection failure by suppressing the drying and solidification of the ink on the nozzle surface of the inkjet head, and preferably have a high vapor pressure. The reason is that it is desirable to evaporate and scatter with moisture in the second step (drying step) described later of the printing method of the present invention. The content of the polyhydric alcohol is preferably in the range of 20% by mass or less with respect to the total amount of the water-based ink composition. By adding polyhydric alcohols within this range, the above-described effects are exhibited. When the content exceeds 20% by mass, even when the second step (drying step) described later of the printing method according to the present invention is performed, the polyhydric alcohols are insufficiently evaporated and consequently the printed matter is not dried. It may be sufficient, and there may be a problem in terms of odor.

  Examples of polyhydric alcohols other than 1,2-alkyldiols having 4 to 8 carbon atoms include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1 , 4-butanediol and the like. Among these, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol are preferable from the viewpoint of high vapor pressure and not hindering the drying property of the aqueous ink composition after printing.

1.1.5.4 Pyrrolidone resin derivative The aqueous ink composition used in the printing method according to the present invention preferably contains a pyrrolidone resin derivative. The pyrrolidone resin derivative in the present invention is selected from those showing water solubility. The water-based ink composition containing this is particularly suitable when a non-ink-absorptive film-type film made of polyvinyl chloride, polyethylene terephthalate, polyethylene, polypropylene or the like is used as a recording medium. The wet spread at the time of adhesion is uniform, and there is a characteristic that a clear and clear image with little shading unevenness and blur can be obtained even in a filled image. The reason for this is not clear, but it is presumed that the pyrrolidone structure contained in the molecular skeleton structure of the pyrrolidone resin derivative has a high affinity for film-based recording media, so that the ink composition containing the pyrrolidone structure also has wettability to the film. Seems to improve. In addition, since the pyrrolidone resin derivative is excellent in compatibility with the above glycol ethers and 1,2-alkylenediol having 4 to 8 carbon atoms, the aqueous ink of the present invention can be contained even if it contains a pyrrolidone resin derivative. The composition can achieve both excellent storage stability and ejection stability. Furthermore, since the pyrrolidone resin derivative functions as a film component after drying, it contributes to improving the abrasion resistance of the printed image.

  As such a pyrrolidone resin derivative, a reagent product or a commercially available product can be used as it is. Specifically, as a reagent product, polyvinylpyrrolidone K-15, polyvinylpyrrolidone K-30, polyvinylpyrrolidone K-60, polyvinylpyrrolidone K-90, Poly (1-vinylpyrrolidone-co-vinyl acetate) copolymer (all made by Tokyo Chemical Industry Co., Ltd.), N-vinylpyrrolidone / styrene copolymer, N-vinylpyrrolidone / diethylaminomethyl methacrylate copolymer (all pure) Chemical Co., Ltd.). As commercially available products, in particular, ruviscose K17 (polyvinylpyrrolidone), ruviscose K30 (polyvinylpyrrolidone), ruviscose K90 (polyvinylpyrrolidone), ruviscose VA73E (vinyl acetate-vinylpyrrolidone copolymer), ruviscose VA64P (acetic acid). Vinyl-vinylpyrrolidone copolymer), ruviscose VA55I (vinyl acetate-vinylpyrrolidone copolymer), ruviscose VA37E (vinyl acetate-vinylpyrrolidone copolymer), ruviscose VA37I (vinyl acetate-vinylpyrrolidone copolymer) , Ruviscose Plus (polyvinylcaprolactam), Rubyset Clear (<vinylpyrrolidone / methacrylamide / vinylimidazole> copolymer) (all manufactured by BASF Japan Ltd.), etc. It is.

  The pyrrolidone resin derivative described above can be added as much as necessary to give desired characteristics to the aqueous ink composition of the present invention, but the preferred addition amount is 10% by mass or less based on the total amount of the aqueous ink composition. It is a range, More preferably, it is the range of 0.1-10 mass%, Most preferably, it is 1 mass%-2 mass%. Within this range, the above-described characteristics can be imparted to the aqueous ink composition, and the viscosity of the aqueous ink composition can be easily adjusted to an appropriate range in the ink jet recording system.

1.1.5.5 Resin Particles The aqueous ink composition used in the printing method according to the present invention preferably contains resin particles.
By including resin particles in the water-based ink composition, an image having better abrasion resistance can be formed on the recording medium. In particular, when printing using a water-based ink composition containing the resin particles on a non-ink-absorbing or low-ink-absorbing recording medium such as a vinyl chloride film or a polypropylene film, the printing method according to the present invention described later is used. By passing through the second step (drying step), an image having excellent abrasion resistance can be formed. The reason is that in the second step (drying step) of the printing method according to the present invention, which will be described later, the resin particles have an action of solidifying the ink and firmly fixing the solidified ink on the recording medium. This action can be further enhanced by heating. In particular, in the water-based ink composition of the present invention, the resin particles are preferably contained in a fine particle state (that is, an emulsion state or a suspension state). By containing the resin particles in a fine particle state, it is easy to adjust the viscosity of the water-based ink composition to an appropriate range in the ink jet recording method, and it is easy to ensure storage stability and ejection stability. Further, by making the resin into a fine particle state, aggregation of the colorant when the ink is landed on the recording medium can be suppressed, and this can contribute to suppression of density unevenness and bleeding.

  The resin particles mainly include polymer particles having an effect of fixing a printed material on a recording medium by forming a resin film by a second step (drying step) of the printing method according to the present invention described later, and the surface of the formed printed material. Wax particles that impart lubricity and improve abrasion resistance. In the aqueous ink composition used in the printing method of the present invention, it is preferable to add polymer particles and wax particles in combination as resin particles. Hereinafter, the polymer particles and the wax particles will be described in detail.

  Examples of the components constituting the polymer particles include polyacrylic acid esters or copolymers thereof, polymethacrylic acid esters or copolymers thereof, polyacrylonitrile or copolymers thereof, polycyanoacrylates, polyacrylamides, and polyacrylic acids. , Polymethacrylic acid, polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene or copolymers thereof, petroleum resin, chroman indene resin, terpene resin, polyvinyl acetate or copolymer thereof, polyvinyl alcohol, polyvinyl acetal, polyvinyl ether , Polyvinyl chloride or copolymers thereof, polyvinylidene chloride, fluororesin, fluororubber, polyvinylcarbazole, polyvinylpyridine, polyvinylimidazole, polybutadiene Copolymers thereof properly, polychloroprene, polyisoprene, and natural resins. Among these, from the viewpoint of dispersibility of particles and wettability to a recording medium, those having both a hydrophobic portion and a hydrophilic portion in the molecular structure are particularly preferable.

  As the above polymer particles, those obtained by known materials and methods can also be used. For example, those described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, JP-A-4-18462 and the like can be used. Good. Commercially available products can also be used. For example, Microgel E-1002, Microgel E-5002 (trade name, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001, Boncoat 5454 (trade name, Dainippon Ink and Chemicals, Inc.) Co., Ltd.), SAE1014 (trade name, manufactured by Zeon Corporation), Cybinol SK-200 (trade name, manufactured by Seiden Chemical Co., Ltd.), Jonkrill 7100, Jonkrill 390, Jonkrill 711, Jonkrill 511, Jonkrill 7001, John Crill 632, John Crill 741, John Crill 450, John Crill 840, John Crill 74J, John Crill HRC-1645J, John Crill 734, John Crill 852, John Crill 7600, John Crill 775, John Crill 537J John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790, John Crill 780, John Crill 7610 (trade name, manufactured by BASF Japan Ltd.) and the like.

  Said polymer particle is obtained by the method shown below, Any method may be sufficient and it may combine a some method as needed. As the method, a polymerization catalyst (polymerization initiator) and a dispersing agent are mixed in a monomer of a component constituting a desired polymer particle, and polymerization (that is, emulsion polymerization) is performed. A method of obtaining particles by dissolving in a water-soluble organic solvent and mixing the solution in water and then removing the water-soluble organic solvent by distillation, etc., dissolving the polymer in a water-insoluble organic solvent and dissolving the solution together with the dispersant in an aqueous solution And the like to obtain particles by mixing. Said method can be suitably selected according to the kind and characteristic of the polymer to be used. The dispersant that can be used for dispersing the polymer in a fine particle state is not particularly limited, but an anionic surfactant (for example, sodium dodecylbenzenesulfonate, sodium lauryl phosphate, polyoxyethylene alkyl ether) Sulfate ammonium salts) and nonionic surfactants (for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, etc.) Alternatively, two or more kinds can be mixed and used.

  The glass transition temperature (hereinafter referred to as “Tg”) of the components constituting the polymer particles described above preferably includes at least one of those having a temperature of room temperature or higher (approximately 30 ° C. or higher). By including a component having a Tg of room temperature or higher, the effect of forming a stronger resin film in the second step (drying step) described later as the printing method of the present invention is high. Therefore, the rub resistance of the printed matter is further improved. Further, ink clogging at the nozzle tip of the ink jet head by the ink jet recording method is unlikely to occur. On the other hand, when polymer particles composed only of components having a Tg of less than room temperature are used, it is difficult to form a strong resin film even after the second step (drying step) described later as the printing method of the present invention. May be poor. Furthermore, ink solidified material may be generated at the nozzle tip, which may cause clogging.

  Examples of components constituting the above wax particles include plant and animal waxes such as carnauba wax, candeli wax, beeswax, rice wax, and lanolin; paraffin wax, microcrystalline wax, polyethylene wax, oxidized polyethylene wax, petrolatum, and the like. Petroleum waxes; mineral waxes such as montan wax and ozokerite; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, stearamide, and natural / synthetic wax emulsions such as α-olefin / maleic anhydride copolymer The compounding wax or the like can be used singly or as a mixture of plural kinds. Among these, preferred wax types are polyolefin waxes, particularly polyethylene wax and polypropylene wax. 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, AQUACER 593 (above trade names, Big Chemie Japan Co., Ltd.).

  The average particle diameter of the resin particles 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 resin particles is preferably 15% by mass or less, more preferably in the range of 0.5% by mass to 10% 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 can be placed on the medium by combining with the second step (drying step) in the printing method of the present invention, particularly on a non-ink-absorbing or low-absorbing recording medium. Can be solidified and fixed firmly. When the content exceeds 15% 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 polymer particles and wax particles are used in combination as resin particles is not yet clear, but is presumed as follows. Since the components constituting the polymer particles have a good affinity for non-ink-absorbing or low-absorbing recording media and water-insoluble colorants, a resin film is formed in the second step (drying step). At this time, it firmly fixes on the recording medium while wrapping the colorant. On the other hand, the component of the wax particles is also present on the surface of the resin film, and has a characteristic of reducing the frictional resistance on the surface of the resin film. This makes it possible to form a resin film that is difficult to be scraped off due to external rubbing and that is difficult to peel off from the recording medium, and it is assumed that the abrasion resistance of the printed matter is improved.

  The content ratio of the polymer particles to the wax particles in the resin particles is preferably in the range of polymer particles: wax particles = 1: 1 to 5: 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.

1.1.6 Other Additive Components The water-based ink composition used in the printing method according to the present invention has a penetrating solvent, a humectant, an antiseptic in addition to the above-described preferable constituent materials and further improving its properties. Agents, fungicides, pH adjusters, chelating agents and the like can be added.

  The penetrating solvent has an action of further improving the wettability of the water-based ink composition with respect to the recording medium and applying it uniformly. As a result, it is possible to further reduce the density unevenness and bleeding of the ink of the formed image. Examples of the penetrating solvent include glycol ethers and monohydric alcohols having an HLB value calculated by the Davis method described above other than 4.2 to 8.0.

  Examples of glycol ethers include diethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. .

  Examples of monohydric alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 2,2-dimethyl-1-propanol, n-butanol, 2-butanol, tertiary butanol, isobutanol, 2-methyl- Water-soluble ones such as 1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tertiary pentanol are exemplified.

  The content of the penetrating solvent is preferably 10% by mass or less, more preferably 8% by mass or less, with respect to the total amount of the aqueous ink composition.

  The humectant has an action of suppressing the evaporation of water in the aqueous ink composition and preventing aggregation of solids such as pigments and polymer particles in the ink. Examples of the humectant include glycerin, tetraethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 2,3-butanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1, 3-hexanediol, 1,2,6-hexanetriol, pentaerythritol, 1,6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl- Examples include 1,3-propanediol, trimethylolethane, trimethylolpropane, urea, 2-imidazolidinone, thiourea, 1,3-dimethyl-2-imidazolidinone, and the like.

  The content of the humectant is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the aqueous ink composition. When the content of the humectant exceeds 10% by mass, the drying speed of the ink may be too slow, and film formation by the polymer particles may be inhibited. For this reason, the solidification / fixing of the ink on the recording medium is hindered, and the printed surface of the printed matter may be peeled off.

  Examples of the pH adjuster include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, Examples thereof include sodium hydrogen carbonate.

  Examples of antiseptics and fungicides include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one Etc. Examples of commercially available products include Proxel XL2, Proxel GXL (above trade name, manufactured by Avicia), Denside CSA, NS-500W (above trade name, manufactured by Nagase ChemteX Corporation), and the like.

  Examples of the rust inhibitor include benzotriazole.

  Examples of chelating agents include ethylenediaminetetraacetic acid and salts thereof (such as ethylenediaminetetraacetic acid dihydrogen disodium salt).

1.2 Physical Properties of Aqueous Ink Composition The pH of the aqueous ink composition is preferably neutral or alkaline, more preferably in the range of 7.0 to 10.0. When the pH is acidic, the storage stability and dispersion stability of the aqueous ink composition may be impaired. In addition, problems such as corrosion of metal parts used in the ink flow path in the ink jet recording apparatus are likely to occur. The pH can be adjusted to neutral or alkaline using the pH adjusting agent described above.

  The viscosity of the water-based ink composition is preferably in the range of 1.5 mPa · s to 15 mPa · s at 20 ° C. Within this range, it is possible to ensure ink ejection stability in the first step described below.

  The surface tension of the water-based ink composition is preferably 20 mN / m to 40 mN / m, more preferably 25 mN / m to 35 mN / m at 25 ° C. Within this range, ink ejection stability can be ensured in the first step described below, and appropriate wettability with respect to a non-ink-absorbing or low-absorbing recording medium can be secured.

1.3 Method for Producing Water-Based Ink Composition The water-based ink composition used in the printing method according to the present invention is prepared by mixing the above-described materials in an arbitrary order and removing impurities by filtering or the like as necessary. can get. Here, the colorant is preferably prepared in advance in a state of being uniformly dispersed in an aqueous medium and then mixed in view of ease of handling and the like.

  As a method for mixing the respective materials, a method in which the materials are sequentially added to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer and stirred and mixed is preferably used. As a filtration method, centrifugal filtration, filter filtration, or the like can be performed as necessary.

2. Printing process will be described in detail each step of the printing method of the ink jet recording system in the printing method according to the invention.

2.1 First Step The first step in the printing method according to the present invention is a step of forming an image by ejecting droplets of the above-described aqueous ink composition onto a recording medium by an inkjet recording method.

  As the inkjet recording method, any method can be used as long as it is a method in which the above-described aqueous ink composition is ejected as droplets from a fine nozzle and the droplets are attached to a recording medium. Examples of the ink jet recording method include the following four methods.

  The first method is called an electrostatic attraction method. A strong electric field is applied between a nozzle and an acceleration electrode placed in front of the nozzle, and ink is continuously ejected from the nozzle in the form of droplets. Is a method in which a print information signal is applied to the deflection electrode while it is flying between the deflection electrodes and recorded, or an ink droplet is ejected corresponding to the print information signal without being deflected.

  The second method is a method in which ink droplets are forcibly ejected by applying pressure to the ink liquid with a small pump and mechanically vibrating the nozzle with a crystal resonator or the like. The ejected ink droplet is charged simultaneously with the ejection, and a printing information signal is given to the deflection electrode and recorded while the ink droplet flies between the deflection electrodes.

  The third method is a method using a piezoelectric element, in which a pressure and a print information signal are simultaneously applied to an ink liquid using a piezoelectric element, and ink droplets are ejected and recorded.

  The fourth method is a method in which the ink liquid is rapidly expanded in volume by the action of thermal energy, and the ink liquid is heated and foamed with a microelectrode in accordance with a print information signal, and ink droplets are ejected and recorded.

  Any recording medium may be used as desired. Among these, in the ink jet recording printing method using the aqueous ink composition having the above-described configuration, a non-ink-absorbing or low-absorbing recording medium can be suitably used. 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 having low ink absorption include printing paper such as art paper, coated paper, and matte paper.

Here, in this specification, “ink non-absorbing and low-absorbing recording medium” means “the amount of water absorption from the start of contact to 30 msec ^1/2 in the Bristow method is 10 mL / m ² or less. Recording medium ". 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".

2.2 Second Step The second step in the printing method according to the present invention is a step of drying the water-based ink composition on the recording medium at least during the first step and after the first step. It is. By incorporating the second step, a liquid medium (specifically, water, glycol ethers, C4-8 1,2-alkyldiol) contained in the aqueous ink composition deposited on the recording medium. ) Quickly evaporate and scatter, and the remaining solids (colorant, etc.) are quickly fixed on the recording medium. Further, in the aqueous ink composition containing a pyrrolidone resin derivative and / or resin particles that can be preferably used as an additive component, these films are further formed. As a result, even when printing on a non-ink-absorbing recording medium such as a plastic film that does not have an ink absorbing layer, a high-quality image with less uneven density and bleeding can be obtained in a short time, which is preferable as an additive component. By forming a film of pyrrolidone resin derivative and / or resin particles that can be used, the dried ink is adhered onto the recording medium, so that the image is firmly fixed.

  The second step is not particularly limited as long as it is a method of promoting evaporation and scattering of the liquid medium present in the aqueous ink composition. As a method used in the second step, a method of applying heat to the recording medium at least during the first step and after the first step, and blowing air to the aqueous ink composition on the recording medium after the first step. The method of attaching, the method of combining them, etc. are mentioned. Specifically, forced air heating, radiation heating, conductive heating, high frequency drying, microwave drying, and the like are preferably used.

  The temperature range for applying heat in the second step is not particularly limited as long as it can promote the evaporation and scattering of the liquid medium present in the aqueous ink composition, but the effect can be obtained if it is 40 ° C. or higher. , Preferably, it is 40 to 80 degreeC, More preferably, it is the range of 40 to 60 degreeC. If the temperature exceeds 80 ° C., defects such as deformation may occur depending on the type of the recording medium, which may hinder the conveyance of the recording medium after the second step, or may contract when the recording medium cools to room temperature. May happen.

  The heating time in the second step is not particularly limited as long as the liquid medium present in the water-based ink composition is evaporated and scattered, and a film of pyrrolidone resin derivatives and / or resin particles that are preferably used can be formed. The liquid medium type, resin particle type, and printing speed to be used can be set as appropriate.

3. EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
3.1 Preparation of aqueous ink composition
3.1.1 Preparation of pigment dispersion The water-based ink composition used in this example used a water-insoluble pigment as a colorant. When the pigment was added to the aqueous ink composition, a resin-dispersed pigment in which the pigment was previously dispersed with a resin dispersant was used.

  The pigment dispersion was prepared as follows. First, an acrylic acid-acrylic acid ester copolymer (weight average molecular weight: 25,000, as a resin dispersant) was added to 76 parts by mass of ion-exchanged water in which 1.5 parts by mass of a 30% aqueous ammonia solution (neutralizing agent) was dissolved. Acid value: 180) 7.5 parts by mass was added and dissolved. Thereto, 15 parts by mass of the following pigment was added, and dispersion treatment was performed for 10 hours by a ball mill using zirconia beads. Thereafter, centrifugal filtration using a centrifugal separator was performed to remove impurities such as coarse particles and dust, and the pigment concentration was adjusted to 15% by mass. Below, the pigment kind used for manufacture of a pigment dispersion liquid is shown.

C. I. Pigment Black 7 (used for black pigment dispersion)
C. I. Pigment Yellow 74 (used for yellow pigment dispersion)
C. I. Pigment Red 122 (used for magenta pigment dispersion)
C. I. Pigment Blue 15: 3 (used for cyan pigment dispersion)
C. I. Pigment Orange 43 (used for orange pigment dispersion)
C. I. Pigment Green 36 (used for green pigment dispersion)

3.1.2 Preparation of Aqueous Ink Composition Using the pigment dispersion prepared in “ 3.1.1 Preparation of Pigment Dispersion ” above, the material composition shown in Table 2 was used for black, yellow, magenta, Cyan, orange and green aqueous ink compositions of 6 colors were prepared to form one ink set, and ink sets 1 to 14 having different material compositions were obtained. For each water-based ink composition, the materials shown in Table 2 are put in a container, mixed by stirring with a magnetic stirrer for 2 hours, and then filtered through a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles. It was prepared by. The numerical values in Table 2 all represent mass%, and ion exchange water was added so that the total amount of ink was 100 mass%.

  In Table 2, “polyvinylpyrrolidone K-15” and “rubiscose plus (polyvinylcaprolactam)” used as pyrrolidone resin derivatives are trade names, which are manufactured by Tokyo Chemical Industry Co., Ltd. and BASF Japan Co., Ltd., respectively. “BYK-348” used as a silicone-based surfactant is a trade name and manufactured by Big Chemie Japan. “Surfinol DF110D”, “Surfinol 104” and “Orphine E1010” used as acetylene glycol surfactants are trade names and are manufactured by Nissin Chemical Industry Co., Ltd.

3.2 Evaluation of aqueous ink composition
3.2.1 Storage Stability of Aqueous Ink Composition Each ink of ink sets 1 to 14 shown in Table 2 was sealed in a sample bottle and allowed to stand in a 60 ° C. environment for 2 weeks. The storage stability of the water-based ink composition was evaluated by observing the change in the viscosity of the ink after standing and the state of separation, sedimentation, and aggregation of the ink components. The evaluation results are shown in Table 3. The evaluation criteria are as follows.

<Viscosity change>
A: Change rate is less than ± 5% compared to the viscosity immediately after preparation B: Change rate is ± 5% or more and less than ± 10% compared to the viscosity immediately after preparation C: Change rate compared to the viscosity immediately after preparation Is ± 10% or more and less than ± 20% D: The rate of change is ± 20% or more compared to the viscosity immediately after preparation

<Separation, sedimentation, and aggregation of ink components>
A: No ink component separation / sedimentation / aggregation B: Ink component separation / sedimentation / aggregation slightly observed C: Ink component separation / sedimentation / aggregation clearly observed D: Ink component separation / sedimentation / aggregation is remarkable

  The storage stability results shown in Table 3 are collectively shown as ink set results because there was no difference between colors in the same ink set.

  As shown in Table 3, the ink sets 1 to 10 which are the aqueous ink composition compositions of the present invention were excellent in storage stability with no problem in viscosity change and separation / sedimentation / aggregation of ink components. In comparison, the ink sets 11 to 14 having the aqueous ink composition composition of the comparative example were inferior in any or all of the viscosity change and the separation / sedimentation / aggregation of the ink components.

3.3 Printing evaluation
3.3.1 Evaluation of bleeding of printed matter P (trade name, manufactured by Fuji Xerox Co., Ltd.) which is a plain paper as a recording medium which absorbs ink well as a recording medium, and a cold laminate film PG which is a non-ink-absorbing polyethylene terephthalate film -50 L (trade name, manufactured by Lamy Corporation) and OK topcoat + (trade name, manufactured by Oji Paper Co., Ltd.), a low-ink-absorbing glossy fine-coated paper, were used.

  Further, as an ink jet recording type printer, an ink jet printer PX-G930 (trade name, manufactured by Seiko Epson Corporation, nozzle resolution: 180 dpi) in which a heater capable of changing the temperature is attached to the paper guide unit was used. This evaluation was performed in a laboratory under room temperature (25 ° C.) conditions.

  An ink jet printer PX-G930 was filled with any one of ink sets 1 to 14 and printed on the recording medium. As the print pattern, different color inks were in contact with each other at a resolution of 360 dpi and 360 dpi, and a pattern that could be printed in 10% increments with a duty in the range of 50% to 100% was used. For the printing conditions, the heater setting of the printer is “no setting (the temperature of the printing surface is room temperature: 25 ° C.)”, “the setting of which the temperature of the printing surface is 40 ° C.”, “the setting of which the temperature of the printing surface is 60 ° C.” , “Setting that the printing surface temperature is 80 ° C.” and “setting that the printing surface temperature is 100 ° C.”. Further, for the printed matter during printing and immediately after printing, wind at a temperature of 25 ° C. (room temperature), 40 ° C., 60 ° C., or 80 ° C. is selected from any one of the three stages of no wind, light wind, and strong wind. The drying process was performed by blowing with air blowing intensity. Of the above blast strengths, “weak wind” has a wind speed on the surface of the recording medium of about 2 m / sec to 5 m / sec, and “strong wind” has a wind speed of about 6 m / sec to 10 m / sec. Indicates the state of sending wind. Moreover, the ventilation time immediately after printing was 1 minute.

  When printed under such conditions, the printed matter was visually confirmed for bleeding in a single color and multiple colors. The results are shown in Tables 4-7. Moreover, the evaluation criteria of the bleeding of the printed matter are as follows.

A: No bleeding was observed even at a duty of 80% or more.
B: No bleeding was observed up to a duty of 70%.
C: No bleeding was observed up to 60% duty.
D: Bleeding was observed even at a duty of 60% or less.

Table 4 shows the printer heater temperature at room temperature (25 ° C.) during printing, Table 5 shows the same 40 ° C. Table 6 shows the same 60 ° C. Table 7 shows the same 80 The results in the case of ° C are shown. As for “ 3.3.1 Evaluation of bleeding on printed matter ”, there was almost no difference between both “cold laminate film PG-50L” and “OK topcoat +”. Table 7 summarizes the results.

  As shown in Tables 4 to 7, in the ink sets 1 to 10 which are the aqueous ink composition compositions of the present invention, a printed matter with less bleeding was obtained through the second step (drying step). However, even with the water-based ink composition of the present invention, there was a case where a printed material with much bleeding was obtained after passing through the second step (drying step) which is not an appropriate condition, but the drying temperature and conditions were appropriately adjusted. It was possible to reduce bleeding. On the other hand, in the ink sets 11 to 14 made of the water-based ink composition of the comparative example, a printed material with much bleeding is obtained even after the second step (drying step), and the bleeding is reduced even when the drying temperature is adjusted. It was difficult. Here, when printing was performed with the printer heater set temperature set to 100 ° C., the temperature applied to the recording medium was too high, and the recording medium was distorted and could not be conveyed without being transported. However, the recording medium was distorted in the process of cooling to room temperature, and it was not suitable as a printed matter.

3.3.2 Density evaluation of printed matter P (trade name, manufactured by Fuji Xerox Co., Ltd.), which is a plain paper as a medium that absorbs ink well as a recording medium, and a cold laminate film, which is a non-ink-absorbing polyethylene terephthalate film PG-50L (trade name, manufactured by Lamy Corporation) and OK top coat + (trade name, manufactured by Oji Paper Co., Ltd.), a low-ink-absorbing glossy fine-coated paper, were used.

  Further, as an ink jet recording type printer, an ink jet printer PX-G930 (trade name, manufactured by Seiko Epson Corporation, nozzle resolution: 180 dpi) in which a heater capable of changing the temperature is attached to the paper guide unit was used. This evaluation was performed in a laboratory under room temperature (25 ° C.) conditions.

  An ink jet printer PX-G930 was filled with any one of ink sets 1 to 14 and printed on the recording medium. As the print pattern, a fill pattern that can be printed at a resolution of 360 dpi in the horizontal direction and 360 dpi in the vertical direction with a duty in the range of 50% to 100% in 10% increments was used. Further, for the printed matter during printing and immediately after printing, wind at a temperature of 25 ° C. (room temperature), 40 ° C., 60 ° C., or 80 ° C. is selected from any one of the three stages of no wind, light wind, and strong wind. The drying process was performed by blowing with air blowing intensity. Of the above blast strengths, “weak wind” has a wind speed on the surface of the recording medium of about 2 m / sec to 5 m / sec, and “strong wind” has a wind speed of about 6 m / sec to 10 m / sec. Indicates the state of sending wind. Moreover, the ventilation time immediately after printing was 1 minute. For the printing conditions, the heater setting of the printer is “no setting (the temperature of the printing surface is room temperature: 25 ° C.)”, “the setting of which the temperature of the printing surface is 40 ° C.”, “the setting of which the temperature of the printing surface is 60 ° C.” , “Setting that the printing surface temperature is 80 ° C.” and “setting that the printing surface temperature is 100 ° C.”.

  The density unevenness of the printed material when printed under such conditions was visually confirmed. The results are shown in Tables 8-11. In addition, the evaluation criteria for the uneven density of the printed matter are as follows.

A: Uneven density was not observed even at a duty of 80% or more.
B: No uneven density was observed up to a duty of 70%.
C: Density unevenness was not observed up to a duty of 60%.
D: Density unevenness was observed even at a duty of 60% or less.

Table 8 shows a printer heater temperature of 25 ° C. (room temperature), Table 9 shows a case of 40 ° C., Table 10 shows a case of 60 ° C., Table 11 shows a temperature of 80 ° C. The result is shown below. Note that there is almost no difference between “Cold Laminate Film PG-50L” and “OK Topcoat +” in “ 3.3.2 Evaluation of uneven density of printed matter ”. 8 to Table 11 are summarized.

  As shown in Tables 8 to 11, in the ink sets 1 to 10 comprising the aqueous ink composition of the present invention, a printed matter with less density unevenness was obtained through the second step (drying step). However, even with the water-based ink composition of the present invention, when the second step (drying step), which is not an appropriate condition, is performed, a printed matter with a large density unevenness may be obtained, but the drying temperature and conditions are appropriately set. By adjusting, the unevenness in density could be reduced. On the other hand, with the ink sets 11 to 14 made of the water-based ink composition of the comparative example, even when the second step (drying step) is performed, a printed matter with much unevenness in density is obtained, and even when the drying temperature is adjusted, the unevenness in density is reduced. It was difficult to make. Here, when printing was performed with the printer heater set temperature set to 100 ° C., the temperature applied to the recording medium was too high, and the recording medium was distorted and could not be conveyed without being transported. However, the recording medium was distorted in the process of cooling to room temperature, and it was not suitable as a printed matter.

3.3.3 Evaluation of Rubbing Resistance of Printed Materials As recording media, a cold laminate film PG-50L (trade name, manufactured by Lamy Corporation), which is a non-ink-absorbing polyethylene terephthalate film, and a gloss-based fine material with low ink absorption Coated paper OK top coat + (trade name, manufactured by Oji Paper Co., Ltd.) was used.

  Further, as an ink jet recording type printer, an ink jet printer PX-G930 (trade name, manufactured by Seiko Epson Corporation, nozzle resolution: 180 dpi) in which a heater capable of changing the temperature is attached to the paper guide unit was used. This evaluation was performed in a laboratory under room temperature (25 ° C.) conditions.

  An ink jet printer PX-G930 was filled with any one of ink sets 1 to 14 and printed on the recording medium. As a print pattern, a fill pattern having a resolution of 360 dpi in the horizontal direction and 360 dpi in the vertical direction was produced. Further, for the printed matter during printing and immediately after printing, wind at a temperature of 25 ° C. (room temperature), 40 ° C., 60 ° C., or 80 ° C. is selected from any one of the three stages of no wind, light wind, and strong wind. The drying process was performed by blowing with air blowing intensity. Of the above blast strengths, “weak wind” has a wind speed on the surface of the recording medium of about 2 m / sec to 5 m / sec, and “strong wind” has a wind speed of about 6 m / sec to 10 m / sec. Indicates the state of sending wind. Moreover, the ventilation time immediately after printing was 1 minute. For the printing conditions, the heater setting of the printer is “no setting (the temperature of the printing surface is room temperature: 25 ° C.)”, “the setting of which the temperature of the printing surface is 40 ° C.”, “the setting of which the temperature of the printing surface is 60 ° C.” , “Setting that the printing surface temperature is 80 ° C.” and “setting that the printing surface temperature is 100 ° C.”.

  Thereafter, the printed surface of the printed matter left for 5 hours in a laboratory at room temperature (25 ° C.) was subjected to a load of 200 g using a Gakushin friction fastness tester AB-301 (trade name, manufactured by Tester Sangyo Co., Ltd.). The rubbing resistance was evaluated by confirming the peeled state of the printed surface and the state of ink transfer to the cotton cloth when rubbed 10 times with the lower / cotton cloth. The evaluation criteria for abrasion resistance are as follows.

A: Even after rubbing 10 times, no ink peeling or ink transfer to the cotton cloth was observed.
B: After rubbing 10 times, ink peeling or ink transfer to a cotton cloth was slightly observed.
C: Ink peeling or ink transfer to cotton cloth was observed after rubbing 10 times.
D: Before tenth rubbing, ink peeling or ink transfer to a cotton cloth was observed.

Table 12 shows the printer heater temperature of 25 ° C. (room temperature), Table 13 shows the same 40 ° C. Table 14 shows the same 60 ° C. Table 15 shows the same 80 ° C. The result is shown below. In addition, there is almost no difference between “Cold Laminate Film PG-50L” and “OK Top Coat +” in “ 3.3.3 Evaluation of abrasion resistance of printed matter ”. The results are shown in Table 12 to Table 15.

  As shown in Tables 12 to 15, in the ink sets 1 to 10 which are the aqueous ink composition compositions of the present invention, a printed material with good abrasion resistance is obtained through the second step (drying step). It was. Ink sets 5 to 10 to which the above-described resin particles (polymer particles, wax particles) and pyrrolidone resin derivatives are added as particularly preferable additive components, printed matter with more excellent abrasion resistance was obtained. However, even with the water-based ink composition of the present invention, when the second step (drying step) which is not appropriate is performed, a printed matter that does not satisfy the desired abrasion resistance may be obtained. The rubbing resistance could be improved by appropriately adjusting the conditions. On the other hand, in the ink sets 11 to 14 composed of the water-based ink composition of the comparative example, a printed matter having inferior abrasion resistance can be obtained even after the second step (drying step), and even if the drying temperature is adjusted, the abrasion resistance It was difficult to improve. Here, when printing was performed with the printer heater set temperature set to 100 ° C., the temperature applied to the recording medium was too high, and the recording medium was distorted and could not be conveyed without being transported. However, the recording medium was distorted in the process of cooling to room temperature, and it was not suitable as a printed matter.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (14)

A first step of forming an image by ejecting droplets of a water-based ink composition on a recording medium by an inkjet recording method;
A second step of drying the water-based ink composition on the recording medium in at least one of the first step and after the first step;
A printing method comprising:
The water-based ink composition includes at least a water-insoluble colorant, glycol ethers having an HLB value calculated by the Davis method within a range of 4.2 to 8.0, and a carbon number of 4 to 8. A printing method of an ink jet recording system, comprising a certain 1,2-alkyldiol and water.   2. The printing method according to claim 1, wherein the alkyl group of the glycol ether has a branched structure.   The inkjet recording method printing method according to claim 1 or 2, wherein the glycol ether is contained in a range of 0.1 mass% to 6 mass% with respect to the total amount of the water-based ink composition.   4. The method according to claim 1, wherein the 1,2-alkyldiols are contained in a mass ratio of 0.5 to 5 times with respect to the glycol ethers. 5. The printing method of the inkjet recording system of description.   The 1,2-alkyldiol is contained in a range of 0.5% by mass to 20% by mass with respect to the water-based ink composition. The printing method of the inkjet recording system as described in 2.   The inkjet recording method printing method according to any one of claims 1 to 5, wherein an alkyl group of the glycol ether is a 2-ethylhexyl group.   The inkjet recording method printing method according to any one of claims 1 to 6, further comprising a nonionic surfactant.   8. The printing method according to claim 7, wherein the nonionic surfactant is a silicone surfactant and / or an acetylene glycol surfactant.   The inkjet recording method printing method according to any one of claims 1 to 8, further comprising a pyrrolidone derivative.   Furthermore, the polyhydric alcohol is included, The printing method of the inkjet recording system as described in any one of Claim 1 thru | or 9 characterized by the above-mentioned.   The inkjet recording method printing method according to any one of claims 1 to 10, further comprising a pyrrolidone resin derivative.   The ink jet recording method printing method according to claim 1, further comprising resin particles.   The inkjet recording method printing method according to any one of claims 1 to 12, wherein a non-ink-absorbing or low-absorbing recording medium is used as the recording medium. In any one of Claims 1 thru / or Claim 13,
The second step includes at least one of a step of heating the recording medium to 40 ° C. to 80 ° C. and a step of blowing air of 40 ° C. to 80 ° C. on the aqueous ink composition on the recording medium. Inkjet printing method.