JP2017071662A - Ink set and production method of printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set that can give a high-quality image while preventing image defects such as blur, color irregularity, white voids and white stripes and preventing a wavy state or curling regardless of a recording medium used in inkjet printing having a fast printing speed and high recording resolution, and to provide a production method of a printed matter effective to solve above mentioned problems in the production of a printed matter using the above ink set.SOLUTION: The ink set comprises: a pretreatment solution comprising a cationic polymeric compound and water; and an inkjet ink comprising a pigment, a water-soluble organic solvent and water. The pretreatment solution has a pH of 3-7; and the inkjet ink has a pH of 7-11. In the ink set, a ratio D50M/D50I is 2 or more, where D50I (nm) represents an average secondary particle diameter of the inkjet ink and D50M (nm) represents an average secondary particle diameter in a solution prepared by mixing the above pretreatment liquid and the inkjet ink by a weight ratio of 1:10.SELECTED DRAWING: None

Description

  The present invention relates to an ink set composed of a pretreatment liquid and inkjet ink, which is capable of obtaining a high-quality image in inkjet printing at a high speed and a high recording resolution regardless of a recording medium. The present invention also relates to a method for producing a printed matter using the ink set.

  Inkjet printing is a recording method in which droplets of inkjet ink ejected from an inkjet head are directly applied to a recording medium to form characters and images. Compared to conventional plate-type printing such as offset printing and gravure printing, it is not necessary to make a plate and can support variable printing. It is easy to operate and adjust the printing device and has low noise during printing. In recent years, there has been an increase in demand for industrial use, including home use and household use.

  Ink jet inks used for ink jet printing are classified into solvent type, aqueous type, UV curable type and the like according to the composition. On the other hand, in recent years, the movement to regulate the use of organic solvents and photosensitive monomers, which are harmful to humans and the environment, has been accelerating, and from solvent-based inks and UV curable inks using these materials to water-based inks. There is a growing demand for replacements.

  The water-based (type) ink-jet ink contains water as a main component, and a water-soluble organic solvent such as glycerin or glycol is added to control wettability and dryability with respect to the recording medium. Further, when a character or image pattern is printed (applied) on a recording medium using an aqueous inkjet ink composed of these liquid components, the liquid components penetrate into the recording medium and / or evaporate from the recording medium. And dried on the recording medium.

On the other hand, there are various types of recording media used in inkjet printing, from those with high permeability such as fine paper and recycled paper to those with low (no) permeability such as coated paper, art paper, and plastic film. To do. In order to further expand the demand for ink-jet printing, the development of water-based ink-jet inks that can be applied to various recording media has become a major challenge for those skilled in the art.

  As a measure against the above problem, a pretreatment liquid treatment for a recording medium is known. In general, as a pretreatment liquid for water-based ink-jet inks, a layer (ink receiving layer) that absorbs liquid components in the ink-jet ink and improves drying properties (see Patent Documents 1 to 4), a coloring material, 2 which forms a layer (ink aggregation layer) which prevents blur between droplets and improves image quality by intentionally aggregating solid components contained in inkjet ink such as resin (see Patent Documents 5 to 6) Kinds are known.

However, in the case of an ink receiving layer, for example, when a large amount of ink is received at once, the recording medium is wavy or curled (curled) due to swelling of the ink receiving layer, or bleeding occurs due to an excess of the acceptable amount. Further, in the case of an ink aggregation layer, since the ability to accept a liquid component is inferior, when a large amount of ink is applied to the ink aggregation layer at once, it takes time to dry the liquid component, so Smudge occurs.

In addition, another problem also exists in the pretreatment liquid shown in Patent Documents 5 to 6. Patent Document 5 discloses a pretreatment liquid containing cationic inorganic fine particles, a water-soluble organic solvent, a siloxane-based antifoaming agent, and water, and the surface tension of the pretreatment liquid is smaller than the surface tension of the inkjet ink. It is characterized. However, in this case, the surface energy of the ink aggregation layer formed by the pretreatment liquid is low, and the ink jet ink applied on the pretreatment liquid cannot be sufficiently wet and spread, resulting in image defects such as white spots and white stripes. End up. Patent Document 6 discloses a pretreatment liquid containing an acidic compound or a nitrogen-containing heterocyclic compound and having a pH of 0.5 to 2.0 at 25 ° C. However, a pretreatment liquid having strong acidity is liable to damage a printing apparatus and a recording medium to be mounted and is not preferable in terms of printability.

  On the other hand, in order to solve the above problem, a method of forming a plurality of layers having different configurations on a recording medium has been reported (see Patent Documents 7 to 8). Since this method can compensate for the drawbacks of the respective layers, it can be said to be suitable when, for example, paper for inkjet ink is manufactured. However, when installing a pretreatment liquid application device in-line with an ink jet printing apparatus in order to cope with an arbitrary base material, it will lead to an increase in size and complexity of the apparatus. I can't say that.

As described above, in the conventional technology, there is no image defect such as bleeding, uneven color, white spot, or white streak in ink jet printing at high speed and high recording resolution regardless of the recording medium to be used, and wavy or curled. However, there was no ink set capable of obtaining a high-quality image.

JP 2000-238422 A JP 2000-335084 A JP 2012-131108 A JP 2009-241304 A Japanese Patent No. 4963783 Japanese Patent No. 5371844 JP 2001-039011 A International Publication No. 2011/019052

The present invention has been made to solve the above-mentioned problems, and its purpose is not to use a recording medium to be used, but also to high-speed and high-resolution ink-jet printing, such as bleeding, uneven color, white spots, and white streaks. It is an object of the present invention to provide an ink set capable of obtaining a high-quality image that is free from image defects and does not wavy or curl. The present invention further provides a production method effective in solving the above-mentioned problems in producing a printed matter using the ink set.

As a result of intensive studies to solve the above-mentioned problems, the present inventors are composed of a pretreatment liquid containing a specific material and an ink-jet ink, and the pH and average secondary particle diameter have a specific range and relationship. The present inventors have found that the above problems can be solved by an ink set, and have completed the present invention.

  That is, the present invention is an ink set comprising a cationic polymer compound and a pretreatment liquid containing water, and an inkjet ink containing a pigment, a water-soluble organic solvent, and water, and the pH of the pretreatment liquid Is 3 to 7, the pH of the inkjet ink is 7 to 11, the average secondary particle diameter of the inkjet ink is D50I (nm), and the pretreatment liquid and the inkjet ink are mixed at a weight ratio of 1:10 It is related with the ink set characterized by D50M / D50I becoming 2 or more when the average secondary particle diameter of the obtained liquid is set to D50M (nm).

In the present invention, when the static surface tension of the pretreatment liquid at 25 ° C. is STP (mN / m) and the static surface tension of the inkjet ink at 25 ° C. is STI (mN / m), the following (1) The present invention relates to an ink set characterized by satisfying the expression (2).
20 ≦ STI ≦ 35 (1)
0 ≦ (STP-STI) ≦ 50 (2)

  The present invention also relates to an ink set, wherein the viscosity of the pretreatment liquid at 25 ° C. is 2 mPa · s or more and 100 mPa · s or less.

  The present invention also relates to an ink set, wherein the pretreatment liquid further contains a surfactant.

  The present invention also relates to an ink set comprising at least a siloxane surfactant and / or an acetylene surfactant as a surfactant contained in a pretreatment liquid.

  The present invention also relates to an ink set comprising at least an epihalohydrin-modified resin as the cationic polymer compound contained in the pretreatment liquid.

  The present invention also relates to an ink set, wherein the cationic polymer compound contained in the pretreatment liquid is present in a dissolved state in the pretreatment liquid.

  In the invention, the water-soluble organic solvent contained in the ink-jet ink contains two or more glycol ether solvents and / or alkyl polyol solvents having a boiling point of 180 ° C. or higher and 280 ° C. or lower at 1 atmosphere. It relates to an ink set.

  The present invention also relates to an ink set, wherein the inkjet ink further contains a binder resin, and the binder resin is present in a dissolved and / or dispersed state in the inkjet ink.

  The present invention also relates to an ink set wherein the inkjet ink further contains a pigment dispersion resin.

Moreover, this invention is a manufacturing method of the inkjet ink printed matter using said ink set, Comprising: After providing a pre-processing liquid on the recording medium conveyed at the speed | rate of 30 m / min or more, the said pre-processing liquid was provided. The present invention relates to a method for producing an ink-jet ink print, characterized in that an ink-jet ink is applied to a portion by a one-pass printing method.

In the present invention, the application amount of the pretreatment liquid onto the recording medium is AQP (mg / inch ² ), and the application amount of the inkjet ink onto the portion to which the pretreatment liquid is applied is AQI (mg / inch ² ). AQI / AQP is 0.1 or more and 10 or less, and relates to a method for producing an ink-jet ink print.

The present invention also relates to a method for producing an ink-jet ink print, wherein the print resolution is 600 dpi or more.

The present invention also relates to a method for producing an ink-jet ink print, which comprises applying a pretreatment liquid on a recording medium and then applying thermal energy to the recording medium before applying the ink-jet ink.

The present invention is a recording medium, the absorption coefficient for water as measured by Bristow's method (J.TAPPI Paper Pulp Test Method Nanba51-87) ^{is, 0ml} / m 2 ^{msec 1/2} or more 0.6 ml ^/ m 2 msec It is related with the manufacturing method of the inkjet ink printed matter characterized by being ^1/2 or less.

The present invention also relates to a method for producing an ink-jet ink print, wherein the means for applying the pretreatment liquid onto the recording medium is a roller system.

According to the present invention, there is no image defect such as blurring, uneven color, white spots, white streaks, and no wavy or curled image, regardless of the recording medium used and in high-speed, high recording resolution ink jet printing. An ink set capable of obtaining a clear image can be provided. Furthermore, when manufacturing a printed matter using the said ink set, the manufacturing method effective in the solution of the said subject came to be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, embodiment described below demonstrates an example of this invention. The present invention is not limited to the following embodiments, and includes modifications that are implemented without departing from the scope of the present invention.

The ink set of the present invention comprises a pretreatment liquid containing a cationic polymer compound and water, an ink-jet ink containing a pigment, a water-soluble organic solvent, and water, and the pH and average secondary particle size are specified. It is characterized by having a range and relationship. As described in the prior art, in inkjet printing, it has been conventionally performed to use a pretreatment liquid and an inkjet ink in combination, but in the present invention, a pretreatment liquid and an inkjet ink having specific materials and characteristics are used. There is a feature in combining. The effect will be described below.

The pretreatment liquid of the present invention is applied onto a recording medium before printing inkjet ink, and forms an ink aggregation layer on the recording medium. The cationic polymer compound contained in the pretreatment liquid causes anion-cation interaction and adsorption equilibrium transfer for solid components such as pigments and resins that are dissolved and / or dispersed in inkjet ink. This lowers the dissolution and / or dispersion function. In addition, the ink-jet ink can be printed before the pretreatment liquid of the present invention is dried. In this case, the mixing equilibrium and the adsorption equilibrium of the solid component are changed by mixing the ink-jet ink and the pretreatment liquid. The dissolution and / or dispersion function of the solid component can be reduced.

In the present invention, the pH range of the pretreatment liquid and the inkjet ink is defined. The reason why the pH of the pretreatment liquid is in the weakly acidic region is to stabilize the cationic polymer compound in the pretreatment liquid and to suppress damage to the pretreatment liquid application apparatus and the recording medium. On the other hand, by making the pH of the inkjet ink weakly basic, the range of selection of solid components that can be used in the inkjet ink can be expanded, and damage to the inkjet head can be suppressed. Furthermore, as described above, by reversing the liquid properties of the pretreatment liquid and the inkjet ink, when both come into contact with each other, the dissolution of the solid component in the inkjet ink and / or the reduction of the dispersion function can be promoted. .

On the other hand, as described in the prior art, since the ink aggregation layer is inferior in moisture acceptability, when a large amount of inkjet ink is applied at once or in a short time, the recording medium derived from the liquid component in the ink It causes rippling and blurring of printed matter. In order to solve the above-mentioned problems, the present invention aims to improve and improve drying properties and image quality by making the configuration of the ink-jet ink suitable. Specifically, by controlling the drying property by adjusting the type and amount of water-soluble organic solvent contained in the inkjet ink, prompt drying on the ink agglomerated layer, and the occurrence of wavy recording media and bleeding of printed matter Can be suppressed.

As described above, the combination of the pretreatment liquid and the inkjet ink of the present invention is an indispensable element in order to obtain a high-quality image regardless of the recording medium and in inkjet printing with high speed and high recording resolution.

On the other hand, not all of the pretreatment liquid and inkjet ink having the configuration of the present invention can solve the above-mentioned problems. The present inventors pay attention to the average secondary particle diameter when the pretreatment liquid and the inkjet ink are mixed at a constant weight ratio as a method for evaluating whether or not the ink set can suitably solve the above problems. The present inventors have found a method for comparing this with the average secondary particle size of the inkjet ink alone. That is, when the average secondary particle diameter of the inkjet ink is D50I (nm) and the average secondary particle diameter of the liquid obtained by mixing the pretreatment liquid and the inkjet ink at a weight ratio of 1:10 is D50M (nm), D50M / When D50I was 2 or more, it was ascertained that the ink set of the present invention can be judged as suitable.
The mixing ratio of the pretreatment liquid and the ink jet ink is based on the ratio of the amounts applied during printing, which will be described later.

  The average secondary particle size can be measured by a conventional method. For example, using a particle size distribution analyzer (Microtrac UPA150 manufactured by Nikkiso Co., Ltd.), the inkjet ink or the mixture is diluted 200 to 1000 times with ion-exchanged water. Can be measured. The average secondary particle diameter is a value of 50% cumulative diameter.

Subsequently, components of the pretreatment liquid of the present invention will be described below.

<Cationic polymer compound>
The pretreatment liquid of the present invention is characterized by containing a cationic polymer compound. The cationic polymer compound is not limited as long as it can lower the dissolution and / or dispersion function of the solid component in the inkjet ink as described above.

Examples of the cation group contained in the cationic polymer compound include, but are not limited to, an amino group, an ammonium group, an amide group, and a —NHCONH ₂ group. Examples of materials used to introduce the cationic group into the cationic polymer compound include amine compounds such as vinylamine, allylamine, methyldiallylamine, and ethyleneimine; amide compounds such as acrylamide, vinylformamide, and vinylacetamide; dicyandiamide Cyanamide compounds such as; epihalohydrin compounds such as epifluorohydrin, epichlorohydrin, methyl epichlorohydrin, epibromohydrin, epiiodohydrin; cyclic vinyl compounds such as vinylpyrrolidone, vinylcaprolactam, vinylimidazole; Examples thereof include compounds; pyridinium salt compounds; imidazolium salt compounds.

  The cationic polymer compound used in the present invention can be synthesized by a known method, or a commercially available product can be used. The following are examples of commercially available products: APC-810, 815; D-6010, 6020, 6030, 6040, 6050, 6060, 6080, 6310, DEC-50, 53, 56, 65; FL-14, 42, 44LF, 61, 2099, 2250, 2273, 2350, 2550, 2565, 2599, 2650, 2850, 2949, 3050, 3150, 4340, 4420, 4440, 4450, 4520, 4530, 4535, 4540, 4620, 4820; FQP-1264; RSL-18-22, 4071H, 4400, 8391, 8391H, HD70C, HF70D; WS-72 (manufactured by SNF), Arafix 100, 251S, 255, 255LOX (manufactured by Arakawa Chemical), DK-6810, 6853, 6885 WS-4 10, 4011, 4020, 4024, 4027, 4030 (manufactured by Seiko PMC), Senka F-300; Papiogen P-105, P-113, P-271, P-316; Pitchnol QG5A; Myriogen P-20 (Senka) Paralock 410K101, 410K111, 420K308, 420K300, 460K313, 460K318, 470K308, 480K300, 490K300, 490K309, 500K30E, 500K40E, 59D, 920AP500, 975AP500, PD700, PD714L, PD714S, P600, (Asada Chemical Co., Ltd.) Sumire resin 650 (30), 675A, 6615, SLX-1 (manufactured by Taoka Chemical Industries), EP-1137; MZ-477, 480; NS-310X, 625 C (manufactured by Takamatsu Yushi Co., Ltd.), PAA-D11-HCL, D19-HCL, D41-HCL, D19A; PAA-HCL-03, 05, 3L, 10L; PAA-1112CL, 21CL, AC5050A, N5050CL, SA; PAS- A-1, 5; PAS-H-1L, 5L, 10L; PAS-J-81, 81L; PAS-M-1, 1A, 1L; PAS-21, 21CL, 22SA-40, 24, 92, 92A, 880, 2201CL, 2401 (manufactured by Nitto Bo Medical Co., Ltd.), PP-17 (manufactured by Meisei Chemical Co., Ltd.); Catio Master PD-1, 7, 30, A, PDT-2, PE-10, PE-30, DT-EH, EPA-SK01, TMHMDA-E (manufactured by Yokkaichi Synthetic Co., Ltd.), Jetfix 36N, 38A, 5052 (manufactured by Satorita Chemical Co., Ltd.)

  In the present invention, the cationic polymer compound preferably contains an epihalohydrin-modified resin into which at least an epihalohydrin compound is introduced. The epihalohydrin-modified resin contains a hydroxyl group and an ammonium group in the resin structure and has a halogen anion, so that the resin has good dissolution stability in the pretreatment liquid, and also dissolves and / or dissolves solid components in the inkjet ink. Or it is excellent in dispersion reduction ability. Although the reason is not clear, printed matter using an epihalohydrin-modified resin is excellent in water resistance. From this point, the epihalohydrin-modified resin is preferably selected. In view of availability, epichlorohydrin or methyl epichlorohydrin is preferably selected as the epihalohydrin.

  Specific examples of the epihalohydrin-modified resin include an epihalohydrin-modified polyamine resin, an epihalohydrin-modified polyamide resin, an epihalohydrin-modified polyamide polyamine resin, and an epihalohydrin-amine copolymer. Among the commercially available products of the cationic polymer compounds exemplified above, as epihalohydrin-modified resins, FL-14 (manufactured by SNF), Arafix 100, 251S, 255, 255LOX (manufactured by Arakawa Chemical Co., Ltd.), DK-6810, 6853, 6885; WS-4010, 4011, 4020, 4024, 4027, 4030 (manufactured by Seiko PMC), Papiogen P-105 (manufactured by Senka), Sumire Resin 650 (30), 675A, 6615, SLX-1 ( Taoka Chemical Industry Co., Ltd.), Catiomaster PD-1, 7, 30, A, PDT-2, PE-10, PE-30, DT-EH, EPA-SK01, TMHMDA-E (Yokkaichi Gosei Co., Ltd.), jet There are Fixes 36N, 38A, and 5052 (manufactured by Satoda Chemical Industries).

  The cationic polymer compound of the present invention may exist in a dissolved state in the pretreatment liquid or may exist in a dispersed state as resin fine particles. However, when the cationic polymer compound is resin fine particles, it is necessary to consider the minimum film forming temperature of the resin fine particles (hereinafter referred to as MFT). MFT is the minimum temperature required for the resin fine particles to fuse and form a film. When the pretreatment liquid using the resin fine particles is dried on the recording medium, the recording medium is brought to a temperature higher than the MFT. If it is not heated, fusion of fine particles does not occur and film formation failure occurs. On the other hand, when the pretreatment liquid contains an organic solvent described later, the organic solvent may function as an auxiliary agent for lowering the MFT, and if the MFT falls below the normal temperature, the printing stability of the pretreatment liquid decreases. There is a possibility that. Therefore, the cationic polymer compound of the present invention is preferably present in a dissolved state in the pretreatment liquid.

  The compounding amount of the cationic polymer compound in the pretreatment liquid of the present invention is preferably 10 to 70% by weight, more preferably 15 to 60% by weight in terms of solid content with respect to the total amount of the pretreatment liquid. It is preferably 20 to 50% by weight, particularly preferably. By keeping the blending amount of the cationic polymer compound within the above range, the viscosity of the pretreatment liquid can be kept within a suitable range, and a pretreatment liquid having excellent storage stability when stored for a long period of time is obtained. Can do. Moreover, when using the cationic polymer compound illustrated above, the said pretreatment liquid and inkjet ink were mixed by the weight ratio of 1:10 by making the compounding quantity in a pretreatment liquid into the said range. The average secondary particle diameter at that time can be made twice or more the average secondary particle diameter of the inkjet ink.

<Surfactant>
The pretreatment liquid of the present invention preferably uses a surfactant in order to adjust the surface tension and improve the wettability on the recording medium. A variety of surfactants are known, such as acetylene-based, siloxane-based, acrylic-based, and fluorine-based surfactants. Wetability on recording media and wettability of inkjet ink applied later In order to make the printing stability of the pretreatment liquid compatible, it is preferable to use a siloxane-based and / or acetylene-based surfactant.

  The surfactant used in the present invention can be synthesized by a known method, or a commercially available product can be used. When the surfactant is selected from commercially available products, for example, BY16-201, FZ-77, FZ-2104, FZ-2110, FZ-2162, F-2123, L-7001, L-7002 as siloxane surfactants. SF8427, SF8428, SH3749, SH8400,8032ADDITIVE, SH3773M (manufactured by Dow Corning Toray Co., Ltd.), Tegoglide410, Tegoglide432, Tegoglide435, Tegoglide440, Tegoglide450, Tegotwin4000, Tegotwin4100, Tegowet250, Tegowet260, Tegowet270, Tegowet280 (manufactured by Evonik Degussa), SAG- 002, SAG-503A (manufactured by Nissin Chemical Industry Co., Ltd.), B K-331, BYK-333, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-UV3500, BYK-UV3510 (manufactured by BYK Chemie), KF-351A, KF-352A, KF -353, KF-354L, KF355A, KF-615A, KF-640, KF-642, KF-643 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like, and Surfynol 61, 104E, 104H, 104A as acetylene surfactants 104BC, 104DPM, 104PA, 104PG-50, 420, 440, 465, 485, SE, SE-F (manufactured by Air Products), Olfin E1004, E1010, E1020, PD-002W, PD-002W, PD-004, PD-005, EXP. 4001, EXP. 4200, EXP. 4123, EXP. 4300 (manufactured by Nissin Chemical Industry Co., Ltd.). Said surfactant may be used independently and may use 2 or more types together.

The addition amount of the surfactant contained in the pretreatment liquid of the present invention is preferably 0.01 wt% or more and 5.0 wt% or less, and 0.05 wt% or more and 3.0 wt% with respect to the total amount of the pretreatment liquid. The following are particularly preferred: However, the blending amount of the surfactant needs to be determined in consideration of the surface tension of the inkjet ink described later.

In the present invention, it is preferable that the surface tension of the pretreatment liquid is equal to or higher than the surface tension of the inkjet ink from the viewpoint of preventing bleeding, white spots and white streaks of the printed matter. Here, when the surface tension of the pretreatment liquid is smaller than the surface tension of the ink-jet ink, the surface energy is reduced by orienting the surfactant on the coating film surface in a large amount when the pretreatment liquid is applied to the recording medium, As a result, the ink-jet ink that will be printed later is insufficiently spread, and bleeding, white spots and white streaks may occur.

<Water-soluble organic solvent>
The pretreatment liquid of the present invention can further contain a water-soluble organic solvent. By using an organic solvent in combination, it is possible to adjust the moisture retention / drying property and wettability of the pretreatment liquid to a more suitable one. Although there is no restriction | limiting in particular as a water-soluble organic solvent which can be used for the pretreatment liquid of the present invention, at least in the molecular structure from the viewpoint of the affinity with water and the cationic polymer compound and the solubility of the cationic polymer compound It is preferable to use a water-soluble organic solvent containing one or more hydroxyl groups.

  Examples of the water-soluble organic solvent suitably used for the pretreatment liquid of the present invention include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-methoxy-1-butanol, and 3-methoxy-3. Monohydric alcohols such as methyl-1-butanol, 1,2-ethanediol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptanediol, 2,2-dimethyl-1 , 3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propyl Pandiol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methylpentane-2,4-diol , 2-ethyl-1,3-hexanediol, 1,2-octanediol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, butylene glycol, dibutylene glycol and other dihydric alcohols (glycols), glycerin, etc. And trihydric alcohols. Among the above exemplary compounds, in the present invention, it is particularly preferable to use monohydric alcohols such as ethanol, 1-propanol, 2-propanol, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol. In addition, the water-soluble organic solvent containing one or more hydroxyl groups in the molecular structure may be used alone or in combination of two or more.

  The amount of the water-soluble organic solvent containing one or more hydroxyl groups in the molecular structure contained in the pretreatment liquid of the present invention is preferably 0.1 to 20% by weight or less based on the total amount of the pretreatment liquid. 0.5 to 10% by weight is more preferable, and 1 to 5% by weight is particularly preferable. By keeping the blending amount of the water-soluble organic solvent within the above range, it is possible to obtain a pretreatment liquid that has both moisture retention, dryness and wettability, and is stable over a long period of time regardless of the printing method of the pretreatment liquid. Printing becomes possible.

  In addition to the pretreatment liquid of the present invention, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, propylene group Cole monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, tripropylene Glycol monoalkyl ethers such as glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol butyl methyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol Glycol dialkyl ethers such as allyl butyl methyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol butyl methyl ether, tetraethylene glycol diethyl ether, 2-pyrrolidone, N-methyl Pyrrolidone, N-ethylpyrrolidone, ε-caprolactam, 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, N, N-dimethyl-β-methoxypropionamide, N, N-dimethyl-β-ethoxypropionamide N, N-dimethyl-β-butoxypropionamide, N, N-dimethyl-β-pentoxypropionamide, N, N-dimethyl-β-hexoxypropionamide, N, N-dimethyl-β-heptoxypropionamide, N, N-dimethyl-β-2-ethylhexoxypropionamide, N, N-dimethyl-β-octoxypropionamide, N, N-diethyl-β- Butoxypropionamide, N, N-diethyl-β-pentoxypropionamide, N, N-diethyl-β-hexoxypropionamide, N, N-diethyl-β-heptoxypropionamide, N, N-diethyl-β Nitrogen-containing solvents such as octoxypropionamide, heterocyclic compounds such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone can be used. Said water-soluble organic solvent may be used independently and may use 2 or more types together.

  The total amount of the water-soluble organic solvent contained in the pretreatment liquid of the present invention is preferably 0.5 to 50% by weight, and preferably 1 to 45% by weight, based on the total amount of the pretreatment liquid. More preferred is 1.5 to 40% by weight. By keeping the blending amount of the water-soluble organic solvent within the above range, it is possible to achieve both the moisture retention, the drying property, and the wettability of the pretreatment liquid.

<Water>
The water content in the pretreatment liquid of the present invention is preferably in the range of 10 to 90% by weight with respect to the total amount of the pretreatment liquid.

<Other materials>
As described above, the pretreatment liquid of the present invention has a pH in the range of 3 to 7, but a pH adjuster can be added to the pretreatment liquid in order to keep the pH within the above range. In the present invention, a material having pH adjusting ability can be arbitrarily selected, and in the case of basification, alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; ammonia water; lithium hydroxide, sodium hydroxide Alkali metal hydroxides such as potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, etc., and hydrochloric acid, sulfuric acid, citric acid, succinic acid when acidifying Tartaric acid, malic acid, phosphoric acid, boric acid, fumaric acid, malonic acid, ascorbic acid, glutamic acid and the like can be used.

  As a compounding quantity of a pH adjuster, it is preferable that it is 0.01 to 5 weight% with respect to the pretreatment liquid whole quantity, and it is more preferable that it is 0.05 to 3 weight%. However, if an excessive amount of the pH adjuster is added, the function of the cationic polymer compound in the pretreatment liquid may be impaired, so the pH of the pretreatment liquid is within the above-mentioned preferred range. It is necessary to adjust the blending amount so that it falls within the range.

<Other ingredients>
The pretreatment liquid of the present invention can be appropriately added with additives such as antifoaming agents and preservatives as necessary in order to obtain desired physical property values. When using these additives, it is preferable that the compounding quantity shall be 0.01 to 10 weight% with respect to the pretreatment liquid whole quantity.

<Pretreatment liquid production method>
The pretreatment liquid of the present invention composed of the above components is, for example, a cationic polymer compound, water, and optionally a surfactant, a water-soluble organic solvent, a pH adjuster, or the like as described above. It is manufactured by adding the additive component selected in the above, stirring and mixing, and then filtering if necessary. However, the method for producing the pretreatment liquid of the present invention is not limited to the above.

  In addition, you may heat the said mixture in the range of 40-100 degreeC as needed in the case of stirring and mixing. However, when resin fine particles are used as the cationic polymer compound, it is preferable to heat at a temperature lower than the MFT of the resin fine particles.

Moreover, when filtering, a filter opening diameter will not be restrict | limited especially if a coarse particle and dust can be removed, However, Preferably it is 0.3-10 micrometers, More preferably, it is 0.5-5 micrometers. Moreover, when filtering, a filter may use single type or may use multiple types together.

<Characteristics of pretreatment liquid>
The pH of the pretreatment liquid of the present invention is set in the range of 3 to 7 in order to stabilize the cationic polymer compound in the liquid and to suppress damage to the pretreatment liquid application apparatus and the recording medium. . A more preferred pH range is 3.5 to 6.5.

  The pH can be measured by a known method, for example, a desktop pH meter F-72 manufactured by HORIBA, Ltd. using a standard ToupH electrode or a sleeve ToupH electrode.

  The pretreatment liquid of the present invention preferably has a viscosity at 25 ° C. adjusted to 2 to 100 mPa · s. Any pretreatment liquid that satisfies the above viscosity range can be applied to various printing methods described below. Moreover, from the viewpoint that an excellent function can be exhibited regardless of the printing method of the pretreatment liquid, the viscosity of the pretreatment liquid at 25 ° C. is more preferably 3 to 80 mPa · s, and 4 to 60 mPa · s. More preferably, it is 5-30 mPa * s.

The viscosity of the pretreatment liquid in the present invention depends on the viscosity of the pretreatment liquid, for example, an E type viscometer (TVE25L viscometer manufactured by Toki Sangyo Co., Ltd.) or a B type viscometer (TVB10 type viscometer manufactured by Toki Sangyo Co., Ltd.). ).

  The surface tension at 25 ° C. of the pretreatment liquid of the present invention is preferably 20 to 75 mN / m, more preferably 22 to 65 mN / m, and particularly preferably 24 to 55 mN / m. Further, as described above, the surface tension of the pretreatment liquid is preferably equal to or higher than the surface tension of the inkjet ink.

The surface tension of the pretreatment liquid in the present invention can be measured by a platinum plate method in a 25 ° C. environment using, for example, a surface tension meter (CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.).

Subsequently, components of the inkjet ink of the present invention will be described below.

<Pigment>
The inkjet ink of the present invention contains a pigment as a coloring material from the viewpoint of having water resistance, light resistance, weather resistance, gas resistance, and the like. In the present invention, any of known organic pigments and inorganic pigments can be used. These pigments are preferably included in the range of 0.1 wt% or more and 20 wt% or less, more preferably in the range of 0.5 wt% or more and 15 wt% or less with respect to the total amount of the inkjet ink, It is particularly preferable that it is contained in the range of 1% by weight or more and 10% by weight or less. By setting the pigment content to 0.1% by weight or more, sufficient color developability can be obtained even in one-pass printing. In addition, when the pigment content is 20% by weight or less, the viscosity of the ink-jet ink can be within a range suitable for ink-jet printing, and as a result, long-term printing stability can be ensured.

Examples of the cyan organic pigment that can be used in the present invention include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 66, and the like. In particular, C.I. I. One or more selected from CI Pigment Blue 15: 3 and / or 15: 4 are preferred.

  Examples of magenta organic pigments that can be used in the present invention include C.I. I. Pigment Red 5, 7, 12, 22, 23, 31, 48 (Ca), 48 (Mn), 49, 52, 53, 57 (Ca), 57: 1, 112, 122, 146, 147, 150, 185 238, 242, 254, 255, 266, 269, C.I. I. Pigment Bio Red 19, 23, 29, 30, 37, 40, 43, 50 and the like. In particular, C.I. I. Pigment red 122, 150, 185, 266, 269 and / or C.I. I. One or more selected from the group consisting of CI Pigment Bio Red 19 is preferable.

  Examples of the yellow organic pigment that can be used in the present invention include C.I. I. Pigment Yellow 10, 11, 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 154, 155, 166, 168, 180, 185, 213 and the like. In particular, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 13, 14, 74, 120, 180, 185 and 213 are preferred.

  Examples of the black organic pigment that can be used in the present invention include aniline black, lumogen black, and azomethine azo black. Further, a plurality of chromatic color pigments such as the above-mentioned cyan pigments, magenta pigments, yellow pigments, and the following orange pigments, green pigments, brown pigments can be used to form black pigments.

  Special colors such as orange pigments, green pigments and brown pigments can also be used in the inkjet ink of the present invention. Specifically, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 64, 71, C.I. I. Pigment green 7, 36, 43, 58, pigment brown 23, 25, 26, and the like.

  Although it does not specifically limit as an inorganic pigment used by this invention, For example, a carbon black and iron oxide can be mentioned as a black pigment, and a titanium oxide can be mentioned as a white pigment.

  Examples of the carbon black pigment that can be used in the present invention include carbon black produced by a furnace method or a channel method. Among these, these carbon blacks have a primary particle size of 11 to 50 nm, a specific surface area of 50 to 400 m <2> / g according to the BET method, a volatile content of 0.5 to 10% by weight, a pH of 2 to 10 and the like. What has is suitable. As a commercial product having such characteristics, for example, No. 25, 30, 33, 40, 44, 45, 52, 850, 900, 950, 960, 970, 980, 1000, 2200B, 2300, 2350, 2600; MA7, MA8, MA77, MA100, MA230 (Mitsubishi Chemical Corporation) Manufactured), RAVEN 760UP, 780UP, 860UP, 900P, 1000P, 1060UP, 1080UP, 1255 (manufactured by Colombian Carbon), REGAL330R, 400R, 660R, MOGUL L (manufactured by Cabot), Nexex 160IQ, 170IQ, 35, 75; PrintX30, 35, 40, 45, 55, 75, 80, 85, 90, 95, 300; Special Black 350, 550; Nerox 305, 500, 505, 600, 605 (Orion Engineered Carbon Etc.) and any of them can be preferably used.

Moreover, as a titanium oxide used suitably as a white inorganic pigment, both an anatase type and a rutile type can be used, but it is preferable to use a rutile type in order to improve the concealability of printed matter. Moreover, although what was manufactured by any methods, such as a chlorine method and a sulfuric acid method, it is preferable to use the titanium oxide manufactured by the chlorine method from whiteness high.

The surface of the titanium oxide pigment that can be used in the present invention is preferably treated with an inorganic compound and / or an organic compound. Examples of inorganic compounds include silicon, aluminum, zirconium, tin, antimony, titanium compounds, and hydrated oxides thereof. Examples of organic compounds include polyhydric alcohols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, organometallic compounds, and the like. Among them, polyhydric alcohols or derivatives thereof highly enhance the surface of titanium oxide. It can be hydrophobized to improve dispersion stability and is preferably used.

  In the present invention, in order to keep the hue and color developability of the printed matter within a suitable range, a plurality of the above pigments can be mixed and used. For example, a small amount of one or more pigments selected from a cyan organic pigment, a magenta organic pigment, an orange organic pigment, and a brown organic pigment is used to improve the color tone at a low printing rate with respect to black ink using a carbon black pigment. Can be added.

<Pigment dispersion resin>
As a method of stably dispersing and holding the pigment in the ink-jet ink, a method of adsorbing and dispersing a pigment dispersion resin on the pigment surface, a method of adsorbing and dispersing a water-soluble and / or water-dispersible surfactant on the pigment surface , A method of chemically and physically introducing a hydrophilic functional group on the pigment surface and dispersing it in the ink without a dispersant or surfactant, a method of coating the pigment with a self-dispersing resin and microencapsulating it, etc. Can be mentioned.

  For the ink-jet ink used in the present invention, it is preferable to select a method using a pigment-dispersed resin among the above. By selecting and examining the monomer composition and molecular weight of the pigment dispersion resin, the resin adsorption capacity for the pigment and the charge of the pigment dispersion resin can be easily adjusted, resulting in imparting dispersion stability to the fine pigment and pre-treatment This is because the ability to reduce the dispersion function of the pigment by the liquid can be controlled.

  The kind of pigment dispersion resin used by this invention is not specifically limited, For example, an acrylic resin, a styrene acrylic resin, a maleic acid resin, a styrene maleic acid resin, a urethane resin, an ester resin etc. can be used. In the present invention, it is particularly preferable to use an acrylic resin or a styrene acrylic resin in terms of material selectivity and ease of synthesis. In addition, the pigment dispersion resin used by this invention can synthesize | combine by a well-known method, and can also use a commercial item.

In the present invention, it is preferable to introduce an alkyl group having 10 to 36 carbon atoms into the pigment dispersion resin. This is because the viscosity of the pigment dispersion, further dispersion stabilization, and viscosity stabilization can be realized by setting the alkyl group to have 10 to 36 carbon atoms. In addition, as carbon number of an alkyl group, Preferably it is C12-30, More preferably, it is C18-24. Further, the alkyl group may be linear or branched as long as it has 10 to 36 carbon atoms, but is preferably linear. Linear alkyl groups include lauryl group (C12), myristyl group (C14), cetyl group (C16), stearyl group (C18), aralkyl group (C20), behenyl group (C22), lignoceryl group (C24), serotoyl Examples thereof include a group (C26), a montanyl group (C28), a meristyl group (C30), a dotriacontanoyl group (C32), a tetratriacontanoyl group (C34), and a hexatriacontanoyl group (C36).

The content of the monomer-containing copolymer containing an alkyl chain having 10 to 36 carbon atoms contained in the pigment-dispersed resin used in the present invention is low in viscosity of the pigment dispersion and rub resistance of the printed matter. From the viewpoint of achieving good balance with gloss and gloss, it is preferably 5% by weight to 60% by weight, more preferably 10% by weight to 55% by weight, and particularly preferably 20% by weight to 50% by weight.

  In the present invention, it is particularly preferable to introduce an aromatic group into the pigment-dispersed resin, since the ability to adsorb the pigment can be improved and the dispersion function of the pigment can be quickly reduced when mixed with the pretreatment liquid. . This is said to be a cation-π interaction between the pigment dispersion resin having a cationic group and an aromatic group in the cationic polymer compound contained in the pretreatment liquid when the pretreatment liquid and the inkjet ink are mixed. This is because strong intermolecular forces work and both adsorb preferentially. Examples of aromatic groups include phenyl, naphthyl, anthryl, tolyl, xylyl, mesityl, and anisyl groups. Of these, a phenyl group and a tolyl group are preferable from the viewpoint of ensuring sufficient dispersion stability.

From the viewpoint of achieving both the pigment dispersion stability and the adsorption performance of the pretreatment liquid, the content of the monomer containing an aromatic ring is preferably 5 to 65% by weight based on the total amount of the pigment dispersion resin. 10 to 50% by weight is more preferable.

  The pigment-dispersed resin of the present invention preferably has a neutralized acid group in the resin with a base in order to increase the solubility in ink. However, if an excessive amount of base is added, the cation component contained in the pretreatment liquid is neutralized, and a sufficient effect cannot be exhibited. Therefore, attention must be paid to the amount added. Whether or not the amount of the base added is excessive can be confirmed, for example, by preparing a 10% by weight aqueous solution of the pigment dispersion resin and measuring the pH of the aqueous solution. In this invention, in order to fully express the function of a pretreatment liquid, it is preferable that the pH of the said aqueous solution is 7-11, and it is more preferable that it is 7.5-10.5.

Examples of the base for neutralizing the pigment dispersion resin used in the present invention include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; ammonia water; lithium hydroxide, sodium hydroxide and potassium hydroxide. Examples thereof include alkali metal hydroxides; alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate, and potassium carbonate.

  In the present invention, the acid value of the pigment dispersion resin is preferably 50 to 400 mgKOH / g. By keeping the acid value within the above range, it is preferable because the solubility of the pigment dispersion resin in water can be secured and the viscosity of the pigment dispersion can be suppressed. On the contrary, when the acid value of the pigment dispersion resin is larger than 400 mgKOH / g, it is preferable because the interaction between the pigment dispersion resins becomes stronger and the viscosity becomes higher or the effect of the pretreatment liquid becomes insufficient. Absent. The acid value of the pigment-dispersed resin is preferably 100 to 350 mgKOH / g, and more preferably 150 to 300 mgKOH / g.

The acid value can be measured by a potentiometric titration method using a known apparatus, for example, “potentiometric automatic titration apparatus AT-610” manufactured by Kyoto Electronics Industry Co., Ltd.

  Regarding the molecular weight of the pigment-dispersed resin, the weight average molecular weight is preferably in the range of 1,000 to 100,000, and more preferably in the range of 5,000 to 50,000. When the molecular weight is in the above range, the pigment is stably dispersed in water, and viscosity adjustment when applied to a water-based ink composition is easy to perform. If the weight average molecular weight is 1,000 or less, the dispersion resin is easy to dissolve in the solvent added to the ink composition, and the resin adsorbed to the pigment is detached, so that the dispersion stability is significantly deteriorated. Resulting in. When the weight average molecular weight is 100,000 or more, the viscosity at the time of dispersion becomes high and the ejection stability from the ink jet head is remarkably deteriorated, so that the printing stability is lowered.

The weight average molecular weight of the pigment-dispersed resin in the present invention can be measured by a conventional method. As an example, using a TSKgel column (manufactured by Tosoh Corp.), GPC equipped with an RI detector (manufactured by Tosoh Corp., HLC-8120GPC) was measured as a weight average molecular weight in terms of polystyrene measured using THF as a developing solvent. can do.

  The weight ratio of the pigment of the present invention to the pigment dispersion resin is preferably 2/1 to 100/1. By adjusting the ratio of the pigment dispersion resin to 2/1 to 100/1, the viscosity of the pigment dispersion is suppressed, and the viscosity stability and dispersion stability of the pigment dispersion and inkjet ink are improved, and the pretreatment liquid This is preferable because it can cause a rapid decrease in the dispersion function when mixed with the. The ratio of the pigment to the pigment dispersion resin is more preferably 20/9 to 50/1, further preferably 5/2 to 25/1, and most preferably 20/7 to 20/1.

<Water-soluble organic solvent>
As the water-soluble organic solvent used in the ink-jet ink of the present invention, a known organic solvent can be arbitrarily used, but a glycol ether solvent and / or an alkyl polyol having a boiling point of 180 ° C. or higher and 280 ° C. or lower at 1 atmosphere. It is preferable to contain 2 or more types of solvent. The boiling point under 1 atm is preferably in the range of 183 ° C. or more and 270 ° C. or less, and more preferably in the range of 185 ° C. or more and 250 ° C. or less. By using a water-soluble organic solvent that satisfies the above boiling range, it is possible to control the wettability and drying properties of the inkjet ink to a suitable range, such as bleeding, white spots and white stripes when combined with the pretreatment liquid. Image quality defects can be prevented. Here, when the boiling point at 1 atm is less than 180 ° C., the drying property of the ink-jet ink is excessively increased, resulting in clogging on the ink-jet head nozzle or even if used together with the pretreatment liquid. Such as image defects may occur, which is not preferable. On the other hand, if the boiling point at 1 atm is 280 ° C. or higher, the drying property of the ink-jet ink is too low, and image defects such as bleeding may occur even when used together with the pretreatment liquid.

  In addition, the boiling point under 1 atmosphere in this invention can be measured by using thermal analyzers, such as DSC (differential scanning calorimetry).

  Examples of glycol ether solvents having a boiling point under 1 atm of 180 ° C. or higher and 280 ° C. or lower that are preferably used in the present invention include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol mono Hexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, dipropylene Glycol monomethyl ether, dipropy Glycol monoalkyl ethers such as diglycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether; diethylene glycol diethyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol butyl methyl Glycol dialkyl ethers such as ether, triethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol diethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether and tetraethylene glycol methyl ethyl ether That.

  In the present invention, among the above glycol ether solvents, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoethyl ether, triethylene glycol monoethyl ether, Ethylene glycol monopropyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, diethylene glycol butyl methyl ether, triethylene glycol methyl ethyl ether, Triethylene glycol diethyl ether, triethylene glycol Chill methyl ether, it is preferable to select a tetraethylene glycol methyl ethyl ether.

  Examples of the alkyl polyol solvent having a boiling point under 1 atm of 180 ° C. or higher and 280 ° C. or lower include 1,2-ethanediol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1, 2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2 -Heptanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 3-methyl-1,3 -Butanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methylpenta 2,4-diol, 2-ethyl-1,3-hexanediol, ethylene glycol, diethylene glycol, dipropylene glycol, and the like dibutylene glycol.

  In the present invention, among the above alkyl polyol solvents, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1, It is preferable to select 2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, and 1,2-heptanediol.

The total amount of the glycol ether solvent and / or alkyl polyol solvent having a boiling point of 180 ° C. or higher and 280 ° C. or lower under the above-mentioned 1 atm used in the present invention is 5 wt% or more and 50 wt% or less with respect to the total amount of the inkjet ink. Preferably there is. Further, from the viewpoint of ensuring the discharge stability from the ink jet nozzle and sufficient wetting and spreading properties when combined with the pretreatment liquid, the total amount of the water-soluble organic solvent is 10% by weight or more and 45% by weight. More preferably, it is 15 to 40% by weight. If the total amount of the water-soluble organic solvent is less than 5% by weight, the moisture retention of the ink is insufficient, and the ejection stability may be impaired. Conversely, when the total content of the water-soluble organic solvent is more than 65% by weight, the viscosity of the ink becomes too high, which may undesirably impair ejection stability.

  In the present invention, in order to adjust the moisture retention and wettability of the ink-jet ink, an organic solvent other than a glycol ether solvent and / or an alkyl polyol solvent having a boiling point of 180 ° C. or higher and 280 ° C. or lower at 1 atmosphere is also used. can do. Specifically, monohydric alcohols, trihydric alcohols, nitrogen-containing solvents, heterocyclic compounds and the like listed above can be used as water-soluble organic solvents that can be used in the pretreatment liquid. These solvents may be used alone or in combination.

  The total amount of the water-soluble organic solvent in the inkjet ink of the present invention is preferably 5% by weight or more and 70% by weight or less based on the total amount of the inkjet ink, from the viewpoint of achieving both moisture retention, drying property, and wettability of the inkjet ink. It is more preferably 10% by weight or more and 60% by weight or less, and particularly preferably 15% by weight or more and 50% by weight or less.

<Binder resin>
It is preferable to add a binder resin to the inkjet ink of the present invention. In general, water-soluble resins and resin fine particles are known as binder resins used in inkjet inks. Among these, the resin fine particles have a higher molecular weight than the water-soluble resin, and the resin fine particles can lower the viscosity of the inkjet ink, and a larger amount of resin can be blended in the inkjet ink. Suitable for increasing resistance. Examples of the resin used as the resin fine particles include acrylic, styrene acrylic, urethane, styrene butadiene, vinyl chloride, and polyolefin. Among these, acrylic and styrene acrylic resin fine particles are preferably used in consideration of the stability of the ink composition and the durability of the printed matter.

However, when the binder resin in the inkjet ink is resin fine particles, it is necessary to consider the MFT of the resin fine particles. When resin particles with a low MFT are used, the MFT of the resin particles is further reduced by the water-soluble organic solvent added to the ink-jet ink, causing the resin particles to be fused and aggregated even at room temperature. This is because clogging may occur. In order to avoid the above problem, it is preferable that the MFT of the resin fine particles is set to 60 ° C. or higher by adjusting the monomer constituting the resin fine particles.

The MFT can be measured by, for example, an MFT tester manufactured by Tester Sangyo Co., Ltd. Specifically, a 25 wt% aqueous solution of resin fine particles was applied on the film so as to have a WET film thickness of 300 μm, and then allowed to stand on the tester with a temperature gradient applied. The temperature at the boundary between the generated region and the region where the transparent resin film is formed is defined as MFT.

However, considering the maintenance performance of the ink jet printer, in the present invention, the binder resin is more preferably a water-soluble resin. The water-soluble resin preferably has a weight average molecular weight in the range of 10,000 to 50,000, more preferably in the range of 20,000 to 40,000. When the weight average molecular weight is 10,000 or less, the coating film resistance of the printed matter is remarkably lowered, which is not preferable. When the weight average molecular weight is 50,000 or more, ejection stability from the ink jet head is remarkably lowered.

  Moreover, when selecting water-soluble resin for binder resin, an acid value is also important, and it is preferable that an acid value is 10-80 mgKOH / g, and it is more preferable that an acid value is 20-50 mgKOH / g. When the acid value is 10 mgKOH / g or less, it is difficult to dissolve again when the ink-jet ink is solidified. Therefore, clogging on the ink-jet head nozzle occurs as in the case of resin fine particles, and the printing stability is significantly reduced. Absent. An acid value of 80 mgKOH / g or more is not preferable because the water resistance of the printed film is significantly deteriorated although the ink can be dissolved again even when the ink-jet ink is solidified.

  The content of the binder resin in the total amount of the ink-jet ink is in the range of 1% by weight to 20% by weight and more preferably in the range of 2% by weight to 15% by weight of the total amount of the ink-jet ink in terms of solid content. Particularly preferably, it is in the range of 3 wt% to 10 wt%.

<Surfactant>
The inkjet ink of the present invention preferably uses a surfactant for the purpose of adjusting the surface tension and improving the image quality. On the other hand, if the surface tension is too low, the nozzle surface of the ink jet head gets wet with the ink jet ink and impairs the discharge stability. Therefore, the selection of the type and amount of the surfactant is very important. From the viewpoint of ensuring optimal wettability and realizing stable ejection from the inkjet nozzle, it is preferable to use siloxane, acetylene, and fluorine surfactants, and siloxane and acetylene surfactants are used. It is particularly preferable to do this. The addition amount of the surfactant is preferably 0.01% by weight or more and 5.0% by weight or less, and more preferably 0.05% by weight or more and 3.0% by weight or less with respect to the total amount of the inkjet ink.

  In addition, the molecular weight of the surfactant is also important in terms of controlling wettability during the process of evaporating the inkjet ink and improving the quality of printed matter such as abrasion resistance and solvent resistance. The molecular weight of the surfactant is preferably 1,000 or more and 7,000 or less, more preferably 1,500 or more and 5,000 or less in terms of weight average molecular weight. If it is 1,000 or less, the effect of controlling the wetting to the printing substrate is small, and if it is 7,000 or more, the wetting to the substrate is improved, but the storage stability of the inkjet ink is deteriorated.

  The surfactant used in the present invention can be synthesized by a known method, or a commercially available product can be used. When the surfactant is selected from commercially available products, for example, as a siloxane surfactant or acetylene surfactant, those listed above as surfactants that can be used in the pretreatment liquid, and as fluorine surfactants , Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 (DuPont), PF-151N, PF-154N (Omnova) Can be mentioned. Said surfactant may be used independently and may use 2 or more types together.

The surfactant used in the inkjet ink and the surfactant used in the pretreatment liquid may be the same or different, but the same one should be used from the viewpoint of the familiarity between the pretreatment liquid and the inkjet ink. preferable. In addition, when using different surfactants, it is better to determine the blending amount after paying attention to the surface tension of both as described above.

<Water>
As water contained in the ink-jet ink of the present invention, it is preferable to use ion-exchanged water (deionized water) instead of general water containing various ions.

The content of water that can be used in the present invention is preferably in the range of 20 to 90% by weight of the total weight of the ink.

<Other ingredients>
In addition to the above components, the ink-jet ink of the present invention may contain additives such as antifoaming agents, preservatives, infrared absorbers, and ultraviolet absorbers in order to obtain inks having desired physical properties as required. It can be added appropriately. As an example of the addition amount of these additives, 0.01% by weight or more and 10% by weight or less is preferable with respect to the total weight of the ink.

In addition, it is preferable that the inkjet ink of this invention does not contain a polymerizable monomer substantially. Here, “substantially does not contain” means that the ink is not intentionally added, and does not exclude a slight amount of mixing or generation when the ink-jet ink is manufactured and stored.

<Inkjet ink set>
The ink-jet ink of the present invention may be used in a single color, but it can also be used as an ink-jet ink set in which a plurality of colors are combined according to the application. The combination is not particularly limited, but a full color image can be obtained by using three colors of cyan, yellow, and magenta. Moreover, the black feeling can be improved by adding black ink, and the visibility of characters and the like can be improved. Furthermore, color reproducibility can be improved by adding colors such as orange and green. When printing on a print medium other than white, a clear image can be obtained by using white ink together.

<Method for producing inkjet ink>
The ink-jet ink of the present invention comprising the above-described components is produced, for example, through the following process. However, the manufacturing method of the inkjet ink of the present invention is not limited to the following.

(1) Production of Pigment Dispersion First, a pigment is added to an aqueous medium in which a pigment dispersion resin and water are mixed, and after mixing and stirring, dispersion processing is performed using a disperser. Thereafter, centrifugation or filtration is performed as necessary to obtain a pigment dispersion.

It is effective to perform premixing before the dispersion processing. Premixing may be performed by adding a pigment to an aqueous medium in which at least a pigment dispersion resin and water are mixed. Such a premixing operation is preferable because it improves wettability of the pigment surface and promotes adsorption of the dispersant to the pigment surface.

The disperser used in the pigment dispersion treatment may be any commonly used disperser, and examples thereof include a ball mill, a roll mill, a sand mill, a bead mill, and a nanomizer. Among the above, a bead mill is preferably used, and specifically, it is commercially available under trade names such as a super mill, a sand grinder, an agitator mill, a glen mill, a dyno mill, a pearl mill, and a cobol mill.

In the pigment premixing and dispersion treatment, the pigment dispersant may be dispersed only in water or may be dispersed in a mixed solvent of an organic solvent and water.

As a method for controlling the particle size distribution of the pigment dispersion, it is possible to reduce the size of the grinding media of the disperser mentioned above, change the material of the grinding media, increase the filling rate of the grinding media, The shape of the agitator) can be changed, the dispersion treatment time can be lengthened, classification can be performed with a filter or a centrifuge after dispersion treatment, and a combination of these methods. In the present invention, in order to keep the pigment in a suitable particle size range, it is preferable that the diameter of the pulverization media of the disperser is 0.1 to 3 mm. Further, glass, zircon, zirconia, and titania are preferably used as the material for the grinding media.

(2) Preparation of inkjet ink Next, the water-soluble organic solvent, water, and, if necessary, the binder resin, surfactant and other additives mentioned above are added to the pigment dispersion, followed by stirring and mixing.

  In addition, you may stir and mix the said mixture, heating in the range of 40-100 degreeC as needed. However, when resin fine particles are used as the binder resin, the heating temperature is preferably set to be equal to or lower than the MFT of the resin fine particles.

(3) Removal of coarse particles Coarse particles contained in the mixture are removed by a technique such as filtration and centrifugation to obtain an inkjet ink. A known method can be appropriately used as the filtration separation method. The filter pore diameter is not particularly limited as long as coarse particles and dust can be removed, but is preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm. Moreover, when filtering, a filter may use single type or may use multiple types together.

<Characteristics of inkjet ink>
The inkjet ink of the present invention preferably has a viscosity at 25 ° C. adjusted to 3 to 20 mPa · s. If it is this viscosity area | region, the stable discharge characteristic will be shown also in the high frequency head of 10-70 KHz especially from the head which has a frequency of normal 4-10 KHz. In particular, by setting the viscosity at 25 ° C. to 4 to 10 mPa · s, even when used for an inkjet head having a design resolution of 600 dpi or more, it can be stably discharged.

The viscosity at 25 ° C. of the inkjet ink in the present invention can be measured by a conventional method. Specifically, an E type viscometer (TVE25L type viscometer manufactured by Toki Sangyo Co., Ltd.) can be used and measured using 1 mL of ink.

The inkjet ink of the present invention preferably has an average secondary particle diameter (D50) of the pigment of 40 nm to 500 nm, more preferably 50 nm to 400 nm, and particularly preferably in order to obtain a printed matter having excellent color developability. Is 60 nm to 300 nm. In order to keep the average secondary particle diameter within the preferable range, the pigment dispersion treatment step may be controlled as described above.

<Method for producing printed matter>
As a method for producing a printed matter using an ink set comprising the pretreatment liquid of the present invention and an inkjet ink, the pretreatment liquid is applied to a recording medium conveyed at a speed of 30 m / min or more, and then the pretreatment liquid is used. A method of applying inkjet ink to the applied portion by a one-pass printing method is preferably used.

  The “one-pass printing method” is a printing method in which an ink jet head is scanned once with respect to a stopped recording medium, or a recording medium is passed only once under a fixed ink jet head. Ink is not printed on the top again. The one-pass printing method has fewer scans than the conventional ink-jet printing method (multi-pass printing method) in which the ink-jet head is scanned a plurality of times, and can increase the printing speed. Preferred. In particular, the adoption of this method is indispensable for realizing inkjet printing as an alternative to offset printing and gravure printing, which has been actively studied in recent years.

  On the other hand, various problems must be solved in order to replace inkjet printing with offset printing or gravure printing. Regarding the printing speed, in order to replace the conventional printing method, it is necessary to support high-speed printing of at least 30 m / min. Needless to say, there is no image defect such as blurring, color unevenness or white spots on the printed matter, but it is essential to obtain a high-quality image at a high recording resolution of 600 dpi or higher. “Recording resolution” is expressed in units of dpi (DotsPerInch) and represents the number of inkjet ink droplets applied per inch. The “recording resolution” in this specification refers to both the recording resolution in the transport direction of the recording medium and the recording resolution in the direction perpendicular to the transport direction (hereinafter referred to as the recording width direction) within the recording medium surface. Shall.

  As described above, in order to realize high-speed printing in inkjet printing, it is essential to employ a one-pass printing method. On the other hand, in order to complete printing in one scan, the amount of ink droplets (drop volume) ejected from the inkjet head nozzle at a time is larger than when the same image is printed by the multi-pass printing method. As described in the prior art, in the case of inkjet ink that contains water as a component and fixes the image by penetrating the recording medium and / or evaporating the liquid component, an increase in the drop volume will cause the inkjet ink to fall through and cause poor drying. In addition, since the permeability of the ink-jet ink differs depending on the recording medium, it has been extremely difficult to obtain a high-quality image regardless of the recording medium.

  The present invention comprises a pretreatment liquid containing a cationic polymer compound and water described above, and an inkjet ink containing a pigment, a water-soluble organic solvent, and water, and has a pH and average secondary particle size. By using an ink set having a specific range or relationship, the above-described problems are solved. That is, by applying the pretreatment liquid on the recording medium before printing the inkjet ink and forming the ink aggregation layer on the recording medium, the influence due to the difference in the type of the recording medium is eliminated. Moreover, by using the inkjet ink suitable for the ink aggregation layer, it is possible to realize rapid aggregation of the solid component and drying of the liquid component. As described above, by using the ink set of the present invention, it is possible to obtain a high-quality image in high-speed and high-resolution inkjet printing regardless of the recording medium.

Below, the manufacturing method of the printed matter using the ink set of this invention is demonstrated.

<Method of applying pretreatment liquid>
In the present invention, a pretreatment liquid is applied on a recording medium that is conveyed at a speed of 30 m / min or higher before printing inkjet ink. As a method of applying the pretreatment liquid onto the recording medium, either a method of printing without contact with the recording medium, such as inkjet printing, or a method of printing with the pretreatment liquid in contact with the recording medium is adopted. May be.

  In recent years, inkjet heads capable of discharging even a liquid composition having a viscosity of about 100 mPa · s at 25 ° C. have been developed by adopting a heater in the head and optimizing the flow path and nozzle structure in the head. The preferred viscosity range at 25 ° C. of the pretreatment liquid of the present invention is 2 to 100 mPa · s, and the pretreatment liquid can be printed without any problem even by ink jet printing. In addition, when adopting ink jet printing as a method for applying the pretreatment liquid, it is possible to apply the pretreatment liquid only to a portion to which the ink jet ink is applied, from the viewpoint of leaving a texture unique to the recording medium in the non-printing portion. preferable.

On the other hand, from the viewpoint of preventing damage to members constituting the ink jet head and ensuring ink jet printing suitability, when using ink jet printing as a pretreatment liquid application method, the pretreatment liquid is constituted depending on the ink jet head used. There may be restrictions on the type and amount of material. Therefore, in the present invention, a printing method in which the pretreatment liquid is brought into contact with the recording medium is preferably used. As the printing method for contacting the pretreatment liquid, a conventionally known printing method can be arbitrarily selected, but from the viewpoint of simplicity of the apparatus, uniform coating property, work efficiency, economy, etc., the roller type is selected. It is preferable to adopt. The “roller format” refers to a printing format in which a pretreatment liquid is applied in advance to a rotating roll and then the pretreatment liquid is transferred to a recording medium. Examples of the roller type coating machine preferably used in the present invention include an offset gravure coater, a gravure coater, a doctor coater, a bar coater, a blade coater, a flexo coater, and a roll coater.

  In the present invention, the coating film thickness of the pretreatment liquid on the recording medium is preferably 0.2 to 10 μm, more preferably 0.3 to 8.5 μm in terms of WET film thickness. It is especially preferable that it is 4-7 micrometers. By setting the coating film thickness within the above range, the original texture of the recording medium is not impaired even in a portion where the pretreatment liquid is applied and the inkjet ink is not applied. In addition, it is preferable to determine the coating film thickness of a pre-processing liquid also considering the application amount of the inkjet ink mentioned later.

<Thermal energy action after pretreatment liquid application>
In the present invention, after applying the pretreatment liquid to the recording medium, it is preferable to apply thermal energy to the recording medium and dry the pretreatment liquid on the recording medium before applying the ink jet ink. In particular, it is preferable that the pretreatment liquid is completely dried before applying the ink jet ink, that is, the liquid component of the pretreatment liquid is completely removed. When the inkjet ink is applied before the pretreatment liquid is completely dried, the dissolution and / or dispersion function of the solid component in the inkjet ink can be further promoted, while the liquid component on the recording medium becomes excessive, If the thermal energy applied after ink jet printing is insufficient, image defects such as waviness and blurring of the recording medium may occur.

  There is no restriction | limiting in particular in the effect | action method of the heat energy used by this invention, For example, a heat drying method, a hot-air drying method, an infrared rays drying method, a microwave drying method, a drum drying method etc. can be mentioned. The above drying methods may be used alone or in combination. For example, by using the heat drying method and the hot air drying method in combination, the pretreatment liquid can be dried more quickly than when each of them is used alone.

  In the present invention, from the viewpoint of preventing damage to the recording medium and bumping of the liquid component in the pretreatment liquid, when the heating drying method is adopted, the drying temperature is set to 35 to 100 ° C. When employing a drying method, the hot air temperature is preferably 50 to 250 ° C. From the same point of view, when the infrared drying method is employed, it is preferable that 50% or more of the integrated value of all infrared output used for infrared irradiation exists in the wavelength region of 700 nm or more and 1500 nm or less.

<Pretreatment liquid application / drying device>
The pretreatment liquid application / drying apparatus of the present invention is equipped in-line or off-line with respect to the ink jet printing apparatus described later, but is preferably equipped in-line from the viewpoint of convenience during printing.

<Inkjet ink application method>
As described above, the inkjet ink is applied to the recording medium by a one-pass printing method. As described above, there are two types of one-pass printing methods: a method in which the inkjet head is scanned once with respect to the recording medium that is stopped, and a method in which the recording medium is passed only once under the fixed inkjet head. However, when the inkjet head is scanned, it is necessary to adjust the ejection timing in consideration of the movement of the inkjet head, and the landing position is likely to shift. Therefore, in the present invention, the inkjet head is fixed and the recording medium is fixed. A method of scanning is preferably used. At that time, the conveyance speed of the recording medium is preferably 30 m / min or more. In particular, when the pretreatment liquid application apparatus is installed in-line with respect to the ink jet printing apparatus, the pretreatment liquid application apparatus to the ink jet printing apparatus are continuously arranged, and the recording medium to which the pretreatment liquid is applied remains as it is. It is preferable to be conveyed to the ink jet printing unit.

  In addition, as described above, by using the ink set of the present invention, a high-quality image can be produced even at a recording speed of 600 dpi or higher, but the image quality equivalent to that of offset printing or gravure printing is used. In particular, the recording resolution of the printed material is preferably 1200 dpi or more from the viewpoint of providing a printed material having the above.

<Inkjet head>
When a method of passing the recording medium only once under the fixed inkjet head as the one-pass printing method, the recording resolution in the recording width direction is determined by the design resolution of the inkjet head. As described above, in the present invention, since the recording resolution in the recording width direction is preferably 600 dpi or more, it is inevitably preferable that the design resolution of the inkjet head is 600 dpi or more. If the design resolution of the inkjet head is 600 dpi or more, printing can be performed with one inkjet head for each color, which is preferable from the viewpoint of miniaturization of the apparatus and economy. When an inkjet head having a design resolution lower than 600 dpi is used, a plurality of inkjet heads for each color are arranged in the transport direction of the recording medium, so that the recording resolution in the recording width direction can be achieved even in one-pass printing. 600 dpi or more can be realized.

The print resolution in the recording medium conveyance direction depends not only on the design resolution of the inkjet head, but also on the drive frequency and print speed of the inkjet head. For example, the print speed is halved or the drive frequency is doubled. By doing so, the recording resolution in the transport direction is doubled. If the inkjet head design cannot achieve a print resolution of 600 dpi or more in the transport direction at a printing speed of 30 m / min or more, printing can be performed by arranging a plurality of ink-jet heads for each color in the transport direction of the recording medium. It is possible to achieve both speed and printing resolution.

  In the ink jet one-pass printing of the present invention, the drop volume of the ink jet ink largely depends on the performance of the ink jet head, but is preferably in the range of 1 to 30 pL in order to realize a high quality image. In order to obtain a high-quality image, it is particularly preferable to use an ink jet head having a gradation specification capable of changing the drop volume.

<Thermal energy action after application of inkjet ink>
It is preferable to apply thermal energy to the recording medium in order to dry the inkjet ink and the undried pretreatment liquid after applying the inkjet ink onto the recording medium to which the pretreatment liquid has been applied. The heat energy operating method and conditions preferably used in the present invention are the same as those used for drying the pretreatment liquid.

<Inkjet ink dryer>
The ink-jet ink drying apparatus is equipped inline or offline with respect to the ink-jet printing apparatus, but is preferably equipped inline from the viewpoint of convenience during printing. In the present invention, in order to prevent bleeding, color unevenness, curling of the recording medium, etc., the thermal energy is preferably applied within 30 seconds after printing, more preferably within 20 seconds, and within 10 seconds. It is particularly preferable to apply.

<Amount of pretreatment liquid and inkjet ink applied>
In the present invention, it is preferable that the ratio of the applied amount of the inkjet ink to the applied amount of the pretreatment liquid is 0.1 or more and 10 or less. The ratio of the applied amounts is more preferably 0.5 or more and 9 or less, and particularly preferably 1 or more and 8 or less. By keeping the ratio of the applied amount in the above range, white spots that occur when the amount of the pretreatment liquid becomes excessive, and bleeding and color unevenness that occur when the amount of the inkjet ink becomes excessive and the effect of the pretreatment liquid becomes insufficient. It is possible to obtain a high quality image without the occurrence of the above.

<Print speed>
As described above, when a printed matter is produced using the ink set of the present invention, the printing speed is preferably 30 m / min or more, more preferably 50 m / min or more, and 75 m / min or more. It is particularly preferred.

<Recording medium>
When printing using the ink set of the present invention, known recording media can be used arbitrarily, such as fine paper, recycled paper, coated paper, art paper, cast paper, finely coated paper, A paper substrate such as synthetic paper, a plastic substrate such as a polyvinyl chloride sheet, a PET film, a polypropylene film, and a polyethylene film can be used. The substrate may have a smooth print medium surface or an uneven surface, and may be transparent, translucent, or opaque. Further, two or more of these print media may be bonded to each other. Further, a peeling adhesive layer or the like may be provided on the opposite side of the printing surface, and an adhesive layer or the like may be provided on the printing surface after printing. Further, the shape of the recording medium used in the present invention may be a roll or a sheet.

In the present invention, the water absorption coefficient measured by the Bristow method (J. TAPPI paper pulp test method No. 51-87) as a recording medium is 0 ml / m ² to sufficiently develop the function of the pretreatment liquid. Those having msec ^1/2 or more and 0.6 ml / m ² msec ^1/2 or less are preferably used. The absorption coefficient for water ^0ml / m 2 ^{msec 1/2} or more 0.3ml ^/ m 2 ^{msec 1/2} or less of the recording medium is preferably ^selected, 0ml / m 2 ^{msec 1/2} or more 0.2 ml / m A recording medium of ² msec ^1/2 or less is particularly preferably selected. As described above, although the permeability of recording media varies greatly depending on the type, the ink set of the present invention is particularly preferably used for recording media with extremely low permeability.

The above absorption coefficient can be measured, for example, by using an automatic scanning liquid absorption meter manufactured by Kumagai Riki Kogyo Co., Ltd. Specifically, the relationship between the water absorption amount (ml / m ² ) and the square root of the contact time (msec ^1/2 ) obtained using the above apparatus and water for a contact time of 100 to 1000 milliseconds. Therefore, the slope of the straight line obtained by the least square method is taken as the absorption coefficient.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, “parts” and “%” represent “parts by weight” and “% by weight”, respectively, unless otherwise specified.

<Production example of pretreatment liquid 1>
The materials listed below were mixed for 1 hour with stirring, adjusted with triethanolamine so that the pH was 5.0 ± 0.5, and then filtered through a membrane filter having a pore size of 1 μm to obtain Pretreatment Solution 1. It was.
-DK-6810 55 parts (Epichlorohydrin-modified polyamine resin manufactured by Seiko PMC, solid content 55%)
・ 2-propanol 4 parts ・ surfinol 465 (acetylene surfactant manufactured by Air Products) 0.1 part ・ proxel GXL 0.05 parts (preservative, 1,2-benzoisothiazole-3-made by Arch Chemicals) ON solution)
・ Ion exchange water 40.85 parts

<Production example of pretreatment liquids 2 to 27>
Pretreatment liquids 2 to 24 were obtained in the same manner as pretreatment liquid 1, except that the materials listed in Table 1 below were used and the pH was adjusted with triethanolamine or hydrochloric acid. However, Table 1 does not describe triethanolamine or hydrochloric acid used for pH adjustment.

In addition, the material described in Table 1 is as follows.
DK-6885: Epichlorohydrin-modified polyamine resin manufactured by Seiko PMC, solid content 70%
・ Cachio Master PD-7: Epichlorohydrin-modified polyamine resin manufactured by Yokkaichi Synthesis Co., Ltd., solid content 50%
・ Arafix 255: Epichlorohydrin-modified polyamide polyamine resin manufactured by Arakawa Chemical Industries, solid content 25%
PAS-H-1L: diallyldimethylammonium chloride polymer manufactured by Nitto Bo Medical, solid content 28%
・ Paraloc 490K300: Acrylic ester / acrylamide copolymer manufactured by Asada Chemical Co., Ltd. ・ EP-1137: Cationic polymer emulsion manufactured by Takamatsu Yushi Co., Ltd. (solid content 20%)
EtOH: ethanol iPrOH: 2-propanol MB: 3-methoxybutanol MMB: 3-methoxy-3-methylbutanol 1,2-PD: 1,2-propanediol 1,2-BuD: 1, 2-butanediol EDG: diethylene glycol monoethyl ether Surfynol 104: acetylene surfactant manufactured by Air Products TegoWet 280: siloxane surfactant manufactured by Evonik Degussa BYK-333: siloxane surfactant manufactured by Big Chemie・ Zonyl FS-300: Fluorosurfactant manufactured by DuPont

<Example of production of pigment dispersion resin 1>
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 93.4 parts of butanol and replaced with nitrogen gas. The inside of the reaction vessel is heated to 110 ° C., and a mixture of 50 parts of acrylic acid as a polymerizable monomer, 50 parts of lauryl methacrylate and 6 parts of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries) over 2 hours. The solution was added dropwise to carry out a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, then 0.6 part of V-601 (manufactured by Wako Pure Chemical Industries) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a dispersion resin 1 solution. It was. Further, after cooling to room temperature, 37.1 parts of dimethylaminoethanol was added for neutralization, and then 100 parts of water was added to make it aqueous. Then, it heated to 100 degreeC or more, butanol was azeotroped with water, butanol was distilled off, and it adjusted so that solid content might be 30%. As a result, an aqueous solution having a solid content of 50% of the pigment dispersion resin 1 was obtained. It was 8.1 when pH of the aqueous solution (solid content 30%) of the pigment dispersion resin 1 was measured using a desktop pH meter F-72 manufactured by HORIBA, Ltd. Moreover, when the weight average molecular weight of the pigment dispersion resin was measured by the method shown above using HLC-8120GPC manufactured by Tosoh Corporation, it was 15,000.

<Example of production of pigment dispersion resin 2>
By using the same method as for the pigment dispersion resin 1 except that 40 parts of styrene, 30 parts of acrylic acid, and 30 parts of behenyl acrylate are used as the polymerizable monomer, an aqueous solution having a solid content of 30% in the pigment dispersion resin 2 Got. The pH of the aqueous solution (solid content 30%) of the pigment dispersion resin 2 was 9.7, and the weight average molecular weight of the pigment dispersion resin 2 was 22,500.

<Example of production of black pigment dispersion 1>
As carbon black, 20 parts of PrinteX85 manufactured by Orion Engineered Carbons, 20 parts of an aqueous solution (solid content 30%) of Pigment Dispersing Resin 1 and 60 parts of water were mixed and predispersed with a disper, and then the diameter was adjusted to 0.00. This dispersion was carried out for 2 hours using a 0.6 L dyno mill filled with 1800 g of 5 mm zirconia beads to obtain a black pigment dispersion 1.

<Example of production of black pigment dispersion 2>
A black pigment dispersion 2 was obtained by using the same method as that of the black pigment dispersion 1 except that an aqueous solution (solid content 30%) of the pigment dispersion resin 2 was used as the pigment dispersion resin.

<Example of water-soluble resin varnish production>
In a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer, 20 parts of Jonkrill 819 (acrylic resin manufactured by BASF, weight average molecular weight 14,500, acid value 75 mgKOH / g), dimethylaminoethanol 2.38. And 77.62 parts of water were added to make it water-soluble. 1 g of this mixed solution was sampled, heated and dried at 180 ° C. for 20 minutes, and the solid content concentration was measured. Based on the obtained solid content concentration, water was added so that the produced water-soluble resin varnish had a non-volatile content of 20%, thereby obtaining a water-soluble resin varnish having a solid content concentration of 20%.

<Production example of inkjet ink 1>
The materials described below were sequentially added to the mixing container while stirring with a disper, and stirred until it was sufficiently uniform. Then, after adjusting with triethanolamine so that pH might be set to 8.0 +/- 0.5, it filtered with the membrane filter with the hole diameter of 1 micrometer, and obtained the inkjet ink 1.
-Black pigment dispersion 1 30 parts-Jonkrill 538 13 parts (acrylic resin emulsion manufactured by BASF, solid content 46%)
・ 1,2-propanediol 10 parts ・ Diethylene glycol monoethyl ether 10 parts ・ Propylene glycol monomethyl ether 5 parts ・ Surfinol 465 0.2 parts ・ Proxel GXL 0.05 parts ・ Ion-exchanged water 31.75 parts

<Example of production of inkjet inks 2 to 10>
Inkjet inks 2 to 7 were obtained in the same manner as inkjet ink 1 except that the materials listed in Table 2 below were used and the pH was adjusted with triethanolamine or hydrochloric acid. However, Table 2 does not describe triethanolamine or hydrochloric acid used for pH adjustment.

In addition, the material which is not described in Table 1 among the materials described in Table 2 is as follows.
CaboJet200: Self-dispersing carbon black aqueous solution manufactured by Cabot, solid content 20%
1,2-PenD: 1,2-pentanediol 1,5-PenD: 1,5-pentanediol 1,2-HexD: 1,2-hexanediol iPDG: diethylene glycol monoisopropyl ether BDG: diethylene glycol Monobutyl ether ・ MFG: Propylene glycol monomethyl ether ・ TEG: Triethylene glycol

<Example of production of recording medium (CP1, 3-19) provided with pretreatment liquid>
Pretreatment liquids 1 and 3 to 19 prepared above were uniformly applied to OK top coat + paper (Oji Paper Co., Ltd.) using a printing tester Easy Proof (Matsuo Sangyo Co., Ltd.). At this time, a 140-wire / inch ceramic roller was used as the roller, and the coating speed was adjusted so that the WET coating amount was 6.0 ± 0.3 cm 3 / m 2. After the pretreatment liquid was applied, the OK topcoat + paper was dried in an air oven at 50 ° C. for 3 minutes to produce recording media (CP1, 3-19) provided with the pretreatment liquid.

<Production example of recording medium (CP7B to 8B, 7C to 8C) to which pretreatment liquid is applied>
As for the pretreatment liquids 7 and 8, a ceramic roller having 400 wires / inch is used as a roller, and the coating speed is adjusted to adjust the coating speed to 1.8 ± 0.2 cm 3 / m 2 (CP7B CP8B), and a ceramic roller with 800 lines / inch of wire as the roller, and adjusting the coating speed to make the wet coating amount 0.6 ± 0.1 cm3 / m2 (CP7C, CP8C) And used for evaluation.

<Examples 1-90 and Comparative Examples 1-20>
An ink jet head KJ4B-QA (manufactured by Kyocera Corporation) was installed on the upper part of the conveyor capable of transporting the recording medium, and was filled with ink jet ink. The inkjet head has a design resolution of 600 dpi and a maximum driving frequency of 30 kHz. When printing is performed at the maximum driving frequency and a printing speed of 75 m / min, the recording resolution in the recording medium conveyance direction is 600 dpi.

Next, after fixing the recording medium to which the pretreatment liquid is applied on the conveyor, the conveyor is driven at a constant speed, and when passing through the installation section of the inkjet head, inkjet ink is ejected at a drop volume of 12 pL, and recording is performed. Solid printing with a recording resolution of 600 dpi in the width direction and a printing rate of 100% was performed. After printing, the printed matter was put in a 50 ° C. air oven within 10 seconds and dried for 3 minutes to prepare a solid printed matter. In addition, printing was performed under the three types of printing conditions shown in Table 3 below, and solid prints with different recording resolution and printing speed in the recording medium conveyance direction were created.

The combinations of recording medium and inkjet ink evaluated above are as shown in Tables 4 to 5 below.

<Examples 91-92>
Two Kyocera inkjet heads KJ4B-QA are installed side by side in the transport direction on the top of the conveyor that can transport the recording medium, the pretreatment liquid 8 is placed on the upstream inkjet head, and the inkjet ink 1 or 7 was filled. Next, after fixing OK top coat + paper (Oji Paper Co., Ltd.) on the conveyor, the conveyor was driven at a speed of 30 m / min. The pretreatment liquid 6 was discharged from the upstream inkjet head onto the recording medium conveyed at a speed of 30 m / min, and solid printing was performed only with the pretreatment liquid at a printing rate of 100%. Within 10 seconds after printing, the printed matter was placed in a 50 ° C. air oven and dried for 3 minutes to produce a recording medium (CP8D) to which a pretreatment liquid was applied. The driving conditions of the inkjet head were a driving frequency of 12 kHz, a drop volume of 12 pL, and a recording resolution in the recording medium conveyance direction was 600 dpi.

Next, after fixing the recording medium CP8D to which the pretreatment liquid is applied on the conveyor, the conveyor is driven at a constant speed, and when passing through the installation portion of the inkjet head, inkjet ink is discharged at a drop volume of 12 pL. Solid printing was performed with a recording resolution of 600 dpi in the recording width direction and a printing rate of 100%. After printing, the printed matter was put in a 50 ° C. air oven within 10 seconds and dried for 3 minutes to prepare a solid printed matter. Note that printing was performed under the three types of printing conditions shown in Table 3 above, and solid prints were produced with different recording resolutions and printing speeds in the recording medium conveyance direction.

<Examples 93 to 94>
The printing apparatus used in Examples 91 to 92 was used, and after fixing OK topcoat + paper (manufactured by Oji Paper Co., Ltd.) on the conveyor, the conveyor was driven at a constant speed. The pretreatment liquid 8 from the upstream ink jet head and the ink jet ink from the downstream ink jet head are ejected onto the recording medium conveyed at a constant speed at a drop volume of 12 pL and a printing rate of 100%, respectively. A solid image provided with inkjet ink on the pretreatment liquid 6 was prepared. After printing, the printed matter was put in a 50 ° C. air oven within 10 seconds and dried for 5 minutes to prepare a solid printed matter. Both inkjet heads performed printing under the three types of printing conditions shown in Table 3 above, and produced solid prints with different recording resolutions and printing speeds in the recording medium conveyance direction.

The combinations of recording medium and inkjet ink evaluated above are as shown in Table 6 below.

<Evaluation of change rate of average secondary particle size when inkjet ink and pretreatment liquid are mixed>
About the pre-processing liquid and inkjet ink which were combined in the said Examples 1-94 and Comparative Examples 1-20, the change rate of the average secondary particle diameter at the time of mixing was evaluated with the following method. The average secondary particle diameter of the inkjet ink was measured using a Microtrac UPA150 manufactured by Nikkiso Co., Ltd., and defined as D50I (nm). Subsequently, 10 g of the inkjet ink and 1 g of the pretreatment liquid were mixed in the combinations described in Tables 4 to 6, and then the average secondary particle diameter was measured in the same manner as in the case of the ink to obtain D50M (nm). At this time, D50M / D50I was calculated, and the change rate of the average secondary particle diameter when the inkjet ink and the pretreatment liquid were mixed was evaluated. The evaluation results obtained in Tables 4 to 6 are shown. In addition, the meaning of the symbol described in the table | surface is as follows. Moreover, since the pre-processing liquid is not used about Comparative Examples 14-20, evaluation is not implemented.
○: D50M / D50I is 2 or more ×: D50M / D50I is less than 2

<Evaluation of solid print>
The following evaluation was performed about the solid printed matter produced in the said Examples 1-99 and Comparative Examples 1-13 from which the conveyor drive conditions differ. The obtained evaluation results are shown in Tables 4-6.

<Evaluation of border blur>
The blur at the boundary between the solid print portion and the non-image portion was visually observed to evaluate the blur at the boundary. The evaluation results are as follows, and Δ or more is good at the boundary.
A: Under all the three types of printing conditions shown in Table 3, no blur was observed at the boundary between the solid print portion and the non-image portion.
○: Among the three types of printing conditions shown in Table 3, no blur was observed at the boundary between the solid print portion and the non-image portion in print conditions A, B, or C, but blur was observed in the remaining print conditions. It was observed.
Δ: Among the three types of printing conditions shown in Table 3, no blur was observed at the boundary between the solid printing portion and the non-image portion under the printing condition A, but bleeding was observed under the printing conditions B and C.
×: Under all the three types of printing conditions shown in Table 3, bleeding was observed at the boundary between the solid print portion and the non-image portion.

<Evaluation of uneven color>
The degree of color unevenness in the solid printing portion was visually observed to evaluate color unevenness. The evaluation results were as follows, and Δ or more was regarded as good color unevenness.
A: Color unevenness was not observed under all three types of printing conditions shown in Table 3.
○: Among the three types of printing conditions shown in Table 3, no color unevenness was observed in printing conditions A, B, or C, but color unevenness was observed in the remaining printing conditions.
Δ: Color irregularity was not observed under printing condition A among the three types of printing conditions shown in Table 3, but color irregularity was observed under printing conditions B and C.
X: Color unevenness was observed under all three types of printing conditions shown in Table 3.

<Evaluation of white spots / white stripes>
The occurrence of white spots and white streaks in the solid print portion was visually observed to evaluate white spots and white streaks. The evaluation results are as follows, and Δ or higher is defined as white blank / white stripe good.
A: No white spots or white streaks were observed under all three printing conditions shown in Table 3.
○: Among the three types of printing conditions shown in Table 3, no white spots or white streaks were found in printing conditions A, B, or C, but white spots or white streaks were seen in the remaining printing conditions. .
Δ: No white spots or white streaks were found under the printing conditions A among the three types of printing conditions shown in Table 3, but white spots or white streaks were seen under the printing conditions B and C.
X: White spots and white streaks were observed under all three types of printing conditions shown in Table 3.

<Evaluation of waves and curls>
The occurrence of undulation and curling of the recording medium in the solid printing part was visually observed to evaluate the undulation and curl. The evaluation results were as follows, and Δ or higher was defined as wavy / curl good.
A: Waves and curls were not observed under all three types of printing conditions shown in Table 3.
○: Among the three types of printing conditions shown in Table 3, no waving or curling was observed under printing conditions A, B, or C, but waving or curling was observed under the remaining printing conditions.
Δ: Among the three types of printing conditions shown in Table 3, no waving or curling was observed under printing condition A, but waving or curling was observed under printing conditions B and C.
X: Rippling and curling were observed under all three printing conditions shown in Table 3.

<Evaluation of dryness of printed matter>
The solid printing part was rubbed 10 times with a cotton swab, and the dryness of the printed matter was evaluated. The evaluation results were as follows, and a value of ◯ or higher was regarded as good dryness of printed matter.
A: In all of the three printing conditions shown in Table 3, no ink adhered to the cotton swab.
○: Among the three types of printing conditions shown in Table 3, no ink adhered to the cotton swabs under the printing conditions A and B. However, under the printing conditions C, ink adhered to the cotton swabs.
Δ: Of the three types of printing conditions shown in Table 3, no ink adhered to the cotton swab under printing condition A, but under printing conditions B and C, ink was observed to adhere to the cotton swab.
X: Adhesion of ink was observed on the cotton swab under all three types of printing conditions shown in Table 3.

<Examples 95 to 113, Comparative Examples 21 to 22>
The following evaluation was performed about pretreatment liquid 1-3, 7, and 11-27. The evaluation results obtained are shown in Table 7.

<Evaluation of coating suitability of pretreatment liquid>
In order to improve the visibility, 0.1 g of KayfectRed Pliquid (a dye made by Nippon Kayaku Co., Ltd.) was added to 10 g of the pretreatment liquid, and well mixed and dissolved. The pretreatment liquid to which the dye was added was uniformly applied to OK top coat + paper (Oji Paper Co., Ltd.) using a printing tester Easy Proof (Matsuo Sangyo Co., Ltd.). At this time, a 140-wire / inch ceramic roller was used as the roller, and the coating speed was adjusted so that the WET coating amount was 6.0 ± 0.3 cm 3 / m 2. After applying the pretreatment liquid, the OK topcoat + paper was dried in an air oven at 50 ° C. for 3 minutes to prepare a recording medium provided with the pretreatment liquid to which the dye was added. Ten recording media provided with the pretreatment liquid to which the dye was added were prepared continuously, and the degree of color unevenness in each recording medium was visually observed to evaluate the coating suitability of the pretreatment liquid. The evaluation results were as follows, and Δ or more was regarded as good coating suitability of the pretreatment liquid.
○: No color unevenness was observed in all 10 sheets.
Δ: Color unevenness was observed in 1 to 2 out of 10 sheets.
X: Color unevenness was observed in 3 or more out of 10 sheets.

<Evaluation of viscosity stability of pretreatment liquid>
The viscosity of the pretreatment liquid was measured at 25 ° C. using an E-type viscometer (TVE25L manufactured by Toki Sangyo Co., Ltd.). After this pretreatment liquid was stored in a thermostat at 70 ° C. and accelerated with time, the viscosity change of the pretreatment liquid before and after aging was evaluated. The evaluation criteria were as follows, and Δ or higher was regarded as good viscosity stability.
○: Viscosity change rate after storage for 4 weeks is less than ± 5% Δ: Viscosity change rate after storage for 2 weeks is less than ± 5% ×: Viscosity change rate after storage for 2 weeks is ± 5% or more

<Examples 114 to 120, Comparative Examples 23 to 25>
The following evaluation was performed about the inkjet inks 1-10. The obtained evaluation results are shown in Table 8.

<Evaluation of ejection stability>
An ink jet ejection device equipped with an ink jet head KJ4B-QA or KJ4B-Z (manufactured by Kyocera Corporation) was prepared and filled with ink jet ink. The inkjet head KJ4B-Z has a design resolution of 1200 dpi and a maximum drive frequency of 64 kHz. When printing is performed at the maximum drive frequency and a printing speed of 80 m / min, the recording resolution in the recording medium conveyance direction is 1200 dpi.

Next, when KJ4B-QA is used, discharge is performed continuously for 2 hours under the conditions of a drop volume of 5 pL and a drive frequency of 30 kHz, and when KJ4B-Z is used of a drop volume of 2 pL and a drive frequency of 64 kHz, then a nozzle check pattern Was printed and the number of nozzles missing was counted to evaluate the ejection stability. The evaluation criteria were as follows, and Δ or higher was regarded as good ejection stability.
○: No nozzle missing in the nozzle check pattern 2 hours after the start of printing Δ: 1 to 9 nozzle missing in the nozzle check pattern 2 hours after the start of printing ×: Nozzle check 2 hours after the start of printing More than 10 nozzles missing in the pattern

<Evaluation of ink dispersion stability>
The average secondary particle diameter of the inkjet ink was measured using a Microtrack UPA150 manufactured by Nikkiso Co., Ltd. This ink was stored in a thermostat at 70 ° C. and accelerated with time, and then the change in average secondary particle diameter of the ink before and after aging was evaluated. The evaluation criteria were as follows, and Δ or higher was regarded as good storage stability.
A: Average particle size change rate after storage for 4 weeks is less than ± 50 nm ○: Average particle size change rate after storage for 2 weeks is less than ± 50 nm Δ: Average particle size change rate after storage for 1 week is less than ± 50 nm ×: Average particle size change rate after storage for 1 week is more than ± 50nm

The ink set and the method for producing a printed matter of the present invention can obtain a high-quality image regardless of the recording medium, and can be suitably used particularly in high-speed and high-resolution recording.

Claims (16)

An ink set comprising a cationic polymer compound and a pretreatment liquid containing water, a pigment, a water-soluble organic solvent, and an inkjet ink containing water,
The pH of the pretreatment liquid is 3 to 7, and the pH of the inkjet ink is 7 to 11,
When the average secondary particle diameter of the inkjet ink is D50I (nm) and the average secondary particle diameter of the liquid obtained by mixing the pretreatment liquid and the inkjet ink at a weight ratio of 1:10 is D50M (nm), D50M / D50I is 2 or more, an ink set. When the static surface tension of the pretreatment liquid at 25 ° C. is STP (mN / m) and the static surface tension of the ink-jet ink at 25 ° C. is STI (mN / m), the following equations (1) to (2) The ink set according to claim 1, wherein:
20 ≦ STI ≦ 35 (1)
0 ≦ (STP-STI) ≦ 50 (2)   The ink set according to claim 1 or 2, wherein the viscosity of the pretreatment liquid at 25 ° C is 2 mPa · s or more and 100 mPa · s or less.   The ink set according to claim 1, wherein the pretreatment liquid further contains a surfactant.   The ink set according to claim 4, wherein the surfactant contains at least a siloxane-based surfactant and / or an acetylene-based surfactant as the surfactant.   The ink set according to any one of claims 1 to 5, comprising at least an epihalohydrin-modified resin as the cationic polymer compound.   The ink set according to claim 1, wherein the cationic polymer compound is present in a dissolved state in the pretreatment liquid.   The water-soluble organic solvent contained in the ink-jet ink contains two or more glycol ether solvents and / or alkyl polyol solvents having a boiling point of 180 ° C. or higher and 280 ° C. or lower under 1 atm. The ink set according to any one of 1 to 7.   The ink set according to any one of claims 1 to 8, wherein the inkjet ink further contains a binder resin, and the binder resin is present in a state of being dissolved and / or dispersed in the inkjet ink.   The ink set according to any one of claims 1 to 9, wherein the inkjet ink further contains a pigment-dispersed resin. It is a manufacturing method of the inkjet ink printed matter using the ink set in any one of Claims 1-10, Comprising: After giving a pretreatment liquid on the recording medium conveyed at the speed | rate of 30 m / min or more, the said pretreatment liquid A method for producing an ink-jet ink print, wherein the ink-jet ink is imparted to the portion imparted with a one-pass printing method. When the application amount of the pretreatment liquid on the recording medium is AQP (mg / inch ² ) and the application amount of the inkjet ink onto the portion to which the pretreatment liquid is applied is AQI (mg / inch ² ), AQI / The method for producing an ink-jet ink print according to claim 11, wherein AQP is 0.1 or more and 10 or less. The method for producing an ink-jet ink print according to claim 11 or 12, wherein the recording resolution of the print is 600 dpi or more. The inkjet ink printed matter according to any one of claims 11 to 13, wherein thermal energy is applied to the recording medium after applying the pretreatment liquid on the recording medium and before applying the inkjet ink. Method. Recording medium was measured by Bristow's method (J.TAPPI Paper Pulp Test Method Nanba51-87), the absorption coefficient for ^{water, 0ml} / m 2 ^{msec 1/2} or more 0.6ml ^/ m 2 ^{msec 1/2} or less The method for producing an ink-jet ink print according to claim 11, wherein: The method for producing an ink-jet ink print according to any one of claims 11 to 15, wherein the means for applying the pretreatment liquid onto the recording medium is a roller system.