JP6772439B2 - Recording method and ink set - Google Patents

Description

The present invention relates to a recording method and an ink set used in the recording method.

Conventionally, there is known an inkjet recording method in which minute ink droplets are ejected from a nozzle of a recording head of an inkjet recording device to record an image on a recording medium. In recent years, the inkjet recording method has not only recorded an image on a recording medium having excellent ink absorbency (for example, plain paper), but also has a recording medium with low ink absorbency (for example, art paper or coated paper) or ink non-absorbent. It has also come to be used for recording images on a recording medium (for example, a plastic film). As an ink used for recording such a low-absorption or non-absorbent recording medium, the use of an aqueous resin ink composition containing a resin emulsion is considered from the viewpoint of global environment and safety to the human body. Has been done.

For example, Patent Document 1 and Patent Document 2 use a water-based ink set including a color ink, a resin ink, and a reaction ink containing the color ink and a reactant that causes agglomeration of the constituent components of the resin ink. The printing method of the inkjet recording method that has been used is disclosed. According to this printing method, in a recorded image recorded on a recording medium that does not absorb ink or has low absorption, the reactant causes agglomeration of constituent components of color ink and resin ink, thereby causing color development and resistance. It is disclosed that a recorded material having excellent scratch resistance can be obtained.

Japanese Unexamined Patent Publication No. 2003-266932 Japanese Unexamined Patent Publication No. 2010-115854

However, in the printing methods disclosed in Patent Document 1 and Patent Document 2, the cohesive force of the constituent components of the color ink and the resin ink may be insufficient in the recording medium having low ink absorption or non-absorption. This may cause deterioration of the image quality and durability of the recorded image.

Further, in a recorded image of a recording medium having low ink absorption or non-absorption, it is also important in terms of quality that there is little odor and excellent glossiness.

Therefore, in some aspects of the present invention, by solving at least a part of the above-mentioned problems, a recorded image having excellent image quality and durability is obtained with respect to a recording medium having low ink absorption or non-absorption. It provides a recording method that can be recorded. Furthermore, some aspects of the present invention provide a recording method capable of recording a recorded image having not only excellent image quality and durability but also excellent glossiness and low odor.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

[Application example 1]
One aspect of the recording method according to the present invention is
A reaction solution attachment step of attaching a reaction solution containing a reactant that aggregates or thickens the colored ink composition to the recording area of the recording medium, and a reaction solution attachment step.
A step of adhering a colored ink composition containing a resin and a coloring material to the recording region to which the reaction solution is attached, and a clear ink adhering a clear ink composition containing a resin. With a composition attachment step,
The resin contained in the colored ink composition includes a resin having a volume of calcium acetate 0.085 mol / kg aqueous solution required for agglutinating 3 mL of water containing the resin at a content of 1% by mass of 7 mL or less. It is a feature.

By using a resin having high reactivity with the reactant contained in the reaction solution as the resin contained in the colored ink composition, the resin contained in the colored ink composition and the reactant react rapidly, and the recorded image is recorded. It is excellent in terms of improved image quality and odor. On the other hand, the agglutination of the resin contained in the colored ink composition causes fine irregularities on the surface of the recorded image, which tends to impair the durability of the image. Further, when the resin contained in the colored ink composition aggregates and becomes large, the glossiness (OD) may decrease. Therefore, by using a clear ink composition containing a resin in combination as in the recording method of Application Example 1, the durability and glossiness of the image can be significantly improved.

[Application example 2]
In the recording method of application example 1,
The resin contained in the clear ink composition may include a resin having a volume of calcium acetate 0.085 mol / kg aqueous solution required for agglutinating 3 mL of water containing the resin at a content of 1% by mass of 5 mL or more. it can.

According to the recording method of Application Example 2, by using a resin having low reactivity with the reactant contained in the reaction solution as the resin contained in the clear ink composition, an adverse effect due to the aggregation of the resin (that is, that is). The durability of the image is reduced and the glossiness is reduced).

[Application example 3]
In the recording method of application example 1 or application example 2,
As the resin contained in the clear ink composition, a resin having a glass transition temperature of 0 ° C. or higher can be included.

[Application example 4]
In the recording method of any one of Application Example 1 to Application Example 3
The average particle size of the resin contained in the clear ink composition can be 200 nm or less.

[Application example 5]
In the recording method of any one of Application Example 1 to Application Example 4
The adhesion of the colored ink composition can be started within 20 seconds from the completion of the adhesion of the reaction solution.

[Application example 6]
In the recording method of any one of Application Example 1 to Application Example 5
The maximum amount of the reaction solution adhering to the recording region can be 0.2 mg / inch ² or more and 3 mg / inch ² or less.

[Application 7]
In the recording method of any one of Application Example 1 to Application Example 6
The reactant may include at least one selected from the group consisting of polyvalent metal salts and organic acids.

[Application Example 8]
In the recording method of any one of Application Example 1 to Application Example 7,
The content of the resin contained in the colored ink composition is 0.5% by mass or more and 13% by mass or less.
The content of the resin contained in the clear ink composition is 1% by mass or more and 17% by mass or less.
The content of the reactant contained in the reaction solution can be 0.1 mol / kg or more and 1.5 mol / kg or less.

[Application 9]
In the recording method of any one of Application Example 1 to Application Example 8
The resin contained in the clear ink composition has a content of 1% by mass of that of the resin contained in the colored ink composition, and 0.085 mol of calcium acetate required for aggregating 3 mL of water containing the resin. It is preferable that the volume of the / kg aqueous solution is large.

[Application Example 10]
In the recording method of any one of Application Example 1 to Application Example 9
The colored ink composition and the clear ink composition can be ejected from the inkjet recording head and adhered to the recording medium, respectively.

[Application Example 11]
One aspect of the ink set according to the present invention is
It is used in the recording method of any one of Application Examples 1 to 10, and is characterized by comprising the reaction solution, the colored ink composition, and the clear ink composition.

The figure which shows typically an example of the image recording apparatus used in the recording method which concerns on this embodiment.

A preferred embodiment of the present invention will be described below. The embodiments described below describe an example of the present invention. Further, the present invention is not limited to the following embodiments, and includes various modifications implemented without changing the gist of the present invention.

1. 1. Recording Method The recording method according to the present embodiment includes (1) a reaction solution adhering step of adhering a reaction solution containing a reactant that aggregates or thickens the colored ink composition to a recording area of a recording medium, and (2) the above. A step of attaching a colored ink composition to which a colored ink composition containing a resin and a coloring material is attached to the recording region to which the reaction solution is attached, and (3) to the recording region to which the reaction solution is attached. On the other hand, a clear ink composition adhering step of adhering a clear ink composition containing a resin is provided, and 3 mL of water containing the resin is aggregated as a resin contained in the colored ink composition at a content of 1% by mass. It is characterized by containing a resin in which the volume of the 0.085 mol / kg aqueous solution of calcium acetate required for the ink is 7 mL or less.

In the present invention, the "image" indicates a recording pattern formed from a group of dots, and includes text printing and a solid image. The "solid image" means that dots are recorded on all pixels, which is the minimum recording unit area defined by the recording resolution, and the recording area of the recording medium is usually covered with ink and the ground of the recording medium. Means an image pattern that should be an image in which is not visible.

Hereinafter, the recording method according to the present embodiment will be described in detail for each of the above steps.

1.1. Reaction solution adhesion step 1.1.1. Description of Step The reaction liquid adhering step is a step of adhering a reaction liquid containing a reactant that aggregates or thickens the colored ink composition to the recording area of the recording medium. When the reactant is adhered to the recording area of the recording medium in advance and the reactant and the colored ink composition are brought into contact with each other, the resin contained in the colored ink composition is a resin having high reactivity with the reactant. , The resin contained in the colored ink composition reacts rapidly with the reactant. Then, the dispersed state of the colorant or the resin in the colored ink composition is destroyed, and the colorant or the resin aggregates. Since this agglomerate inhibits the penetration of the colorant into the recording medium, it is considered to be excellent in improving the image quality of the recorded image.

In the present embodiment, the recording medium to be printed is not particularly limited, but it is preferable to record on a recording medium having low ink absorption or non-absorption. In a recording medium with low ink absorption or non-absorption, the reaction solution hardly penetrates into the recording medium and the reactant tends to remain on the surface of the recording medium. Therefore, it is a component of a colored ink composition or a clear ink composition. When the cohesive force is insufficient, the image quality of the recorded image is significantly reduced and the durability of the recorded image is significantly reduced. Therefore, the present invention is particularly effective for recording media having low ink absorption or non-absorption. However, since better image quality can be obtained by adhering the colored ink composition or the clear ink composition as soon as possible after the reaction liquid adhering step, a recording medium having low ink absorbency that slightly absorbs ink is used. More preferred.

As used herein, the term "ink low-absorbent or non-absorbent recording medium" refers to a recording medium having the property of not absorbing or hardly absorbing an ink composition. Quantitatively, the ink non-absorbent or low-absorbent recording medium is "a recording medium in which the amount of water absorbed from the start of contact to 30 msec ^1/2 in the Bristow method is 10 mL / m ² or less". Point to. This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Pulp and Paper Technology Association (JAPAN TAPPI). For details of the test method, refer to the standard No. of "JAPAN TAPPI Pulp and Paper Test Method 2000 Edition". It is described in 51 "Paper and Paperboard-Liquid Absorption Test Method-Bristow Method". On the other hand, the ink-absorbent recording medium refers to a recording medium that does not correspond to an ink-non-absorbent or low-absorbency recording medium.

Examples of the ink non-absorbent recording medium include a plastic film having no ink absorbing layer, a material coated with plastic on a base material such as paper, and a medium to which a plastic film is adhered. .. Examples of the plastic referred to here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene and the like.

Examples of the recording medium having low ink absorption include a recording medium having a coating layer provided on the surface for receiving ink. For example, a recording medium whose base material is paper includes art paper, coated paper, and matte. Printing of paper, etc. When this paper is a plastic film, the surface of polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene, etc. is coated with a hydrophilic polymer. , Silica, titanium and other particles are coated together with a binder.

As a method for adhering the reaction solution to the recording medium, for example, any method such as spin coating, spray coating, gravure roll coating, reverse roll coating, bar coating, and an inkjet method can be used, but by using the inkjet method, It is preferable in that the coating amount of the reaction solution can be controlled and the layer of the reaction solution can be formed thinly.

When the reaction solution is attached to a recording medium by using an inkjet method, it is preferably attached at a resolution of 600 × 600 dpi or more and a droplet amount of 10 ng / dot or less. By adhering the reaction solution under such recording conditions, it is preferable that the reaction solution can be adhered uniformly even if the reaction solution is adhered with a small amount of adhesion.

When the reaction solution is adhered to a recording medium by using an inkjet method, a line-type inkjet head is used to adhere the reaction solution in one relative scan between the head and the recording medium, and a serial-type inkjet head is used. The head and the recording medium may be attached to each other by a multipath method, but the former is preferable in terms of recording speed.

The maximum amount of the reaction solution adhered to the recording region is preferably 0.2 mg / inch ² or more and 3.0 mg / inch ² or less, and more preferably 0.5 mg / inch ² or more and 2.0 mg / inch ² or less. .. Since the resin contained in the colored ink composition is a resin having high reactivity with the reactant, even if the maximum amount of the reaction solution adhered to the recording region is as small as within the above range, the colored ink composition contains the resin. It is possible to sufficiently destroy the dispersed state of the colorant and the resin.

In addition, before the reaction liquid adhesion step, in order to improve the wettability of the recording medium with respect to the reaction liquid, a surface modification step of modifying the surface of the recording medium may be performed. For example, by modifying the surface of a recording medium having low ink absorption or non-absorption so that the wetting tension index is 40 mN / m or more, the wettability of the reaction solution can be improved and the reaction solution can be used as a recording medium. Can be evenly adhered on. Here, the "wetting tension index" is a wetting tension measured according to "Plastic-film and sheet-wetting tension test method (JIS K6768: 1999)".

Such a surface modification step is not particularly limited, and examples thereof include corona treatment, atmospheric pressure plasma treatment, frame treatment, ultraviolet irradiation treatment, solvent treatment, resin liquid adhesion treatment (for example, primer treatment) and the like. Can be mentioned. These treatment methods can be carried out using a known device.

On the other hand, after the reaction solution adhering step, a drying step of drying the reaction solution adhering to the recording area of the recording medium may be provided. In this case, it is preferable to dry the reaction solution until it does not feel sticky when it comes into contact with the reaction solution adhered to the recording area of the recording medium. The drying step of the reaction solution may be carried out by natural drying, or may be drying accompanied by heating. The method for heating the reaction solution is not particularly limited, and examples thereof include a heat press method, a normal pressure steam method, a high pressure steam method, and a thermofix method. Further, as a heat source for heating, for example, infrared rays (lamp) can be mentioned.

1.1.2. Reaction solution Next, the reaction solution used in the reaction solution adhesion step will be described. The reaction solution used in this embodiment contains a reactant and other components for agglutinating or thickening the colored ink composition. Hereinafter, the components contained in the reaction solution used in the present embodiment and the components that can be contained will be described in detail.

<Reactant>
The reaction solution used in the present embodiment acts on the resin particles contained in the colored ink composition to act on the resin particles.
Contains a reactant that causes agglomeration or thickening. Examples of the reactant include polyvalent metal salts, organic acids, and cationic compounds (cationic resins, cationic surfactants, etc.). These reactants may be used alone or in combination of two or more. Among these reactants, it is preferable to use at least one reactant selected from the group consisting of polyvalent metal salts and organic acids from the viewpoint of excellent reactivity with the resin contained in the colored ink composition. ..

The polyvalent metal salt is a compound that is composed of divalent or higher polyvalent metal ions and anions that bind to these polyvalent metal ions and is soluble in water. Specific examples of polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Zn ²⁺ , and Ba ²⁺ ; and trivalent metal ions such as Al ³⁺ , Fe ³⁺ , and Cr ^3+. Be done. Examples of anions include Cl ⁻ , I ⁻ , Br ⁻ , SO ₄ ^2- , ClO ^3- , NO ^3- , HCOO ⁻ , CH ₃ COO ^{− and the} like. Among these polyvalent metal salts, calcium salts and magnesium salts are preferable from the viewpoint of stability of the reaction solution and reactivity as a reactant.

Examples of organic acids include sulfuric acid, hydrochloric acid, nitrate, phosphoric acid, polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid and tartrate acid. , Lactic acid, sulfonic acid, ortholic acid, pyrrolidone carboxylic acid, pyroncarboxylic acid, pyrrolcarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumarin acid, thiophenecarboxylic acid, nicotinic acid, or derivatives of these compounds, or salts thereof. Etc. are preferably mentioned. The organic acid may be used alone or in combination of two or more.

Examples of the cationic resin include a cationic urethane resin, a cationic olefin resin, and a cationic allylamine resin.

As the cationic urethane resin, known ones can be appropriately selected and used. As the cationic urethane resin, commercially available products can be used, for example, Hydran CP-7010, CP-7020, CP-7030, CP-7040, CP-7050, CP-7060, CP-7610 (trade name, trade name, Dainippon Ink and Chemicals Co., Ltd.), Superflex 600, 610, 620, 630, 640, 650 (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Urethane emulsion WBR-2120C, WBR-2122C (trade name, Taisei) Fine Chemical Co., Ltd.) and the like can be used.

The cationic olefin resin has an olefin such as ethylene or propylene in its structural skeleton, and known ones can be appropriately selected and used. Further, the cationic olefin resin may be in an emulsion state in which it is dispersed in a solvent containing water, an organic solvent and the like. As the cationic olefin resin, a commercially available product can be used, and examples thereof include arrow base CB-1200 and CD-1200 (trade name, manufactured by Unitika Ltd.).

As the cationic allylamine resin, known ones can be appropriately selected and used. For example, polyallylamine hydrochloride, polyallylamine amide sulfate, allylamine hydrochloride / diallylamine hydrochloride copolymer, allylamine acetate / diallylamine acetate Copolymers, allylamine acetate / diallylamine acetate copolymers, allylamine hydrochloride / dimethylallylamine hydrochloride copolymers, allylamine / dimethylallylamine copolymers, polydiallylamine hydrochloride, polymethyldiallylamine hydrochloride, polymethyldialylamineamide sulfate, polymethyldiallylamine acetate , Polydiallylamine dimethylammonium chloride, diallylamine acetate / sulfur dioxide copolymer, diallylmethylethylammonium ethylsulfate / sulfur dioxide copolymer, methyldiallylamine hydrochloride / sulfur dioxide copolymer, diallyldimethylammonium chloride / sulfur dioxide copolymer, diallyldimethylammonium chloride / Examples thereof include acrylamide copolymers. Commercially available products can be used as such cationic allylamine-based resins, and for example, PAA-HCL-01, PAA-HCL-03, PAA-HCL-05, PAA-HCL-3L, PAA-HCL- 10L, PAA-H-HCL, PAA-SA, PAA-01, PAA-03, PAA-05, PAA-08, PAA-15, PAA-15C, PAA-25, PAA-H-10C, PAA-D11- HCL, PAA-D41-HCL, PAA-D19-HCL, PAS-21CL, PAS-M-1L, PAS-M-1, PAS-22SA, PAS-M-1A, PAS-H-1L, PAS-H- 5L, PAS-H-10L, PAS-92, PAS-92A, PAS-J-81L, PAS-J-81 (trade name, manufactured by Nittobo Medical Co., Ltd.), Hymo Neo-600, Hymorok Q-101, Q-311 , Q-501, Himax SC-505, SC-505 (trade name, manufactured by Hymo Co., Ltd.) and the like can be used.

Examples of the cationic surfactant include primary, secondary and tertiary amine salt type compounds, alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalconium salts, and quaternary ammonium salts. Examples thereof include quaternary alkylammonium salt, alkylpyridinium salt, sulfonium salt, phosphonium salt, onium salt, and imidazolinium salt. Specific examples of cationic surfactants include hydrochlorides such as laurylamine, coconut amine and rosinamine, acetates and the like, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, benzyltributylammonium chloride, benzalconium chloride and dimethylethyllaurylammonium. Ethyl sulfate, dimethylethyloctylammonium ethyl sulfate, trimethyllaurylammonium hydrochloride, cetylpyridinium chloride, cetylpyridinium bromide, dihydroxyethyllaurylamine, decyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium chloride, tetradecyldimethylammonium chloride, hexa Examples thereof include decyldimethylammonium chloride and octadecyldimethylammonium chloride.

The content of the reactant can be appropriately determined so as to exert the above-mentioned effect. For example, the content of the reactant is preferably 0.1 mol / kg or more and 1.5 mol / kg or less in 1 kg of the reaction solution, and is 0. More preferably, it is 2 mol / kg or more and 1.3 mol / kg or less. The content of the reactant is, for example, preferably 0.5% by mass or more and 25% by mass or less, and more preferably 1% by mass or more and 20% by mass or less, based on the total mass of the reaction solution.

<Water>
The reaction solution used in this embodiment preferably uses water as the main solvent. This water is a component that evaporates and scatters due to drying after adhering the reaction solution to the recording area of the recording medium. As the water, it is preferable that ionic impurities such as pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water, and distilled water or ultrapure water are removed as much as possible. Further, it is preferable to use water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide because the growth of mold and bacteria can be prevented when the reaction solution is stored for a long period of time. The content of water contained in the reaction solution can be, for example, 50% by mass or more with respect to the total mass of the reaction solution.

<Organic solvent>
An organic solvent may be added to the reaction solution used in the present embodiment. By adding an organic solvent, the wettability of the reaction solution with respect to the recording medium can be improved. As the organic solvent, the same organic solvent as those exemplified in the colored ink composition described later can be used. The content of the organic solvent is not particularly limited, but can be, for example, 1% by mass or more and 40% by mass or less with respect to the total mass of the reaction solution.

<Surfactant>
A surfactant may be added to the reaction solution used in the present embodiment. By adding a surfactant, the surface tension of the reaction solution can be reduced and the wettability with the recording medium can be improved. Among the surfactants, for example, an acetylene glycol-based surfactant, a silicon-based surfactant, and a fluorine-based surfactant can be preferably used. As specific examples of these surfactants, the same surfactants as those exemplified in the colored ink composition described later can be used. The content of the surfactant is not particularly limited, but can be 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the reaction solution.

<Other ingredients>
A pH adjuster, a preservative / fungicide, a rust preventive, a chelating agent and the like may be added to the reaction solution used in the present embodiment, if necessary.

1.2. Colored ink composition adhesion step 1.2.1. Description of Step The Colored Ink Composition Adhesion Step is a step of adhering a colored ink composition containing a resin and a coloring material to a recording region to which the reaction solution is adhered after the above-mentioned reaction solution adhering step. .. Since the resin contained in this colored ink composition has high reactivity with the reactant contained in the reaction solution, the resin contained in the colored ink composition reacts rapidly with the reactant to improve the image quality of the recorded image. It will be excellent in terms of.

In the step of adhering the colored ink composition, droplets of the colored ink composition are ejected from the nozzle of the head for inkjet recording and adhered to the recording region to which the reaction solution of the recording medium described above is adhered, thereby adhering to the recording region. It records an image. As a result, an image composed of the colored ink composition is formed in the recording area of the recording medium.

Adhesion of the colored ink composition is preferably started within 30 seconds from the completion of adhesion of the reaction solution. The upper limit is more preferably 20 seconds or less, further preferably 15 seconds or less, still more preferably 10 seconds or less, more preferably 7 seconds or less, and particularly preferably 5 seconds or less. The lower limit is 0 seconds or longer, preferably 0.05 seconds or longer, more preferably 0.1 seconds or longer, still more preferably 0.5 seconds or longer, and particularly preferably 1 second or longer. By starting the adhesion of the colored ink composition within 30 seconds from the completion of the adhesion of the reaction solution, the colored ink composition can be adhered before the reaction solution permeates the recording medium in the recording area of the recording medium. , The reactant contained in the reaction solution and the resin contained in the colored ink composition can be rapidly reacted. Therefore, the image quality of the recorded image can be further improved and the recording speed can be increased.

The maximum amount of the colored ink composition adhered to the recording area is preferably 5 mg / inch ² or more and 15 mg / inch ² or less. When the maximum amount of the colored ink composition adhered to the recording area is within the above range, the amount of the reactant adhering to the reaction solution in the recording area is relative to the amount of the resin contained in the colored ink composition. It is preferable in that the ratio becomes an appropriate amount and the recording speed can be increased.

After the colored ink composition adhering step, a drying step of drying the colored ink composition adhering to the recording area of the recording medium may be provided. In this case, it is preferable to dry the colored ink composition so that it does not feel sticky when it comes into contact with the colored ink composition adhered to the recording area of the recording medium. The drying step of the colored ink composition may be carried out by natural drying, but from the same viewpoint as the above-mentioned drying step of the reaction solution, it may be dried with heating. The method for heating the colored ink composition is not particularly limited, and examples thereof include the same methods as those mentioned in the above-mentioned method for heating the reaction solution.

1.2.2. Colored Ink Composition Next, the colored ink composition used in the step of adhering the colored ink composition will be described. The colored ink composition used in the present embodiment contains a resin, a colorant, and other components. Hereinafter, the components contained in the colored ink composition used in the present embodiment and the components that can be contained will be described in detail.

<Resin>
The resin contained in the colored ink composition is a resin having a volume of 0.085 mol / kg aqueous solution of calcium acetate required for aggregating 3 mL of water containing the resin at a content of 1% by mass of 7 mL or less. The required volume is preferably 5 mL or less, more preferably 3 mL or less, still more preferably 2 mL or less, and particularly preferably 1 mL or less. The lower limit of the required volume is preferably 0.1 mL or more from the viewpoint of availability. Since such a resin has very high reactivity with the above-mentioned reactant, the resin contained in the colored ink composition reacts rapidly with the reactant in the recording region of the recording medium. As a result, the dispersed state of the colorant and the resin in the colored ink composition is destroyed, and the colorant and the resin are aggregated or thickened. Since this agglomerate inhibits the permeation of the colorant into the recording medium, it is possible to prevent landing interference and bleeding of the colored ink composition to be adhered thereafter, and it is possible to uniformly draw lines and fine images. Therefore, it is considered to be excellent in terms of improving the image quality of the recorded image. In addition, the odor can be reduced by the rapid reaction between the resin contained in the colored ink composition and the reactant.

The resin having high reactivity is not particularly limited, but (1) an anionic resin having an anionic functional group introduced on the surface, or (2) an acid value of 5 mgKOH / g or more. It is preferable to use a resin (preferably 20 mg / g or more, more preferably 40 mg / KOH or more) or (3) a self-dispersing resin that does not depend on an emulsifier. Here, the "anionic resin" refers to a resin having a negative charge as a whole. The "self-dispersing resin" is a resin that does not require a dispersant and can be dispersed by itself.

Examples of the resin material include acrylic resin, urethane resin, polyolefin resin, polyester resin, vinyl acetate copolymer resin, ionomer resin and the like.

As the form of the resin, resin particles (resin emulsion) or water-soluble resin can be used, but resin particles (resin emulsion) are preferable in terms of the above-mentioned effects.

Among these, the anionic resin emulsion having an anionic functional group on the surface can have higher reactivity (reduce the volume related to the reaction) and can rapidly bond with the reactant by electrostatic interaction. preferable. Examples of the anionic functional group include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a group derived from these.

In the present specification, the "acid value" means the number of mg of KOH required to neutralize 1 g of the resin solid content, and can be measured by the method described in JIS K0070, for example, the electrodeposition titration method. ..

The lower limit of the solid content of the resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, in that it sufficiently reacts with the reactant with respect to the total mass of the colored ink composition. , Particularly preferably 0.5% by mass or more. On the other hand, the upper limit is preferably 13% by mass or less, more preferably 10% by mass or less, still more preferably 7% by mass or less, and particularly preferably 5% by mass in terms of storage stability and ejection stability of the colored ink composition. % Or less.

<Colorant>
The colored ink composition used in this embodiment contains a colorant. As the colorant, a pigment or an acid dye can be preferably used from the viewpoint that the effects of the present invention can be easily obtained.

Among the pigments, examples of the inorganic pigment include carbon black, iron oxide, and titanium oxide. The carbon black is not particularly limited, and examples thereof include furnace black, lamp black, acetylene black, and channel black (CI pigment black 7). In addition, as a commercially available product of carbon black, for example, No. 2300, 900, MCF88, No. 20B, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B (all product names above, manufactured by Mitsubishi Chemical Corporation), Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U, Special Black 6, 5, 4A, 4, 250 (all product names, manufactured by Degussa AG), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700 (all product names, Colombian Carbon) Made by Columbian Carbon Japan Ltd), made by Columbia Chemicals, Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all above) Product name, manufactured by Cabot Corporation).

Examples of organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanslon pigments, flavanthron pigments, perylene pigments, and diketo. Examples thereof include pyrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. Specific examples of the organic pigment include the following.

Examples of the pigment used in the cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat blue 4, 60 can be mentioned.

Pigments used in magenta ink include C.I. I. Pigment Red 1,2,3,4,5,6,7,8,9,10,11,12,14,15,16,17,18,19,21,22,23,30,31,32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 , 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

Pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213 and the like.

Examples of pigments used for inks of colors other than the above, such as green ink and orange ink, include conventionally known pigments. These pigments may be used alone or in combination of two or more.

Examples of acid dyes include azo-based, anthraquinone-based, pyrazolone-based, phthalocyanine-based, xanthene-based, indigoid-based, and triphenylmethane-based acid dyes. Specific examples of acid dyes include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94 and the like can be mentioned. These acid dyes may be used alone or in combination of two or more.

<Water>
The colored ink composition used in this embodiment preferably uses water as the main solvent. This water is a component that evaporates and scatters due to drying after the colored ink composition is attached to the recording area of the recording medium. As the water, it is preferable that ionic impurities such as pure water such as ion-exchanged water, ultra-filtered water, reverse osmosis water, and distilled water or ultrapure water are removed as much as possible. Further, it is preferable to use water sterilized by irradiation with ultraviolet rays or addition of hydrogen peroxide because the growth of mold and bacteria can be prevented when the colored ink composition is stored for a long period of time. The content of water contained in the colored ink composition can be, for example, 50% by mass or more with respect to the total mass of the colored ink composition.

<Organic solvent>
An organic solvent may be added to the colored ink composition used in the present embodiment. By adding an organic solvent, the wettability of the colored ink composition with respect to the recording medium is improved, the fixability of the recorded image on the recording medium is improved, and the ejection stability is improved by preventing the ejection head from drying. The function to be used can be added to the ink.

The organic solvent is not particularly limited, and examples thereof include 1,2-alkanediols, polyhydric alcohols (excluding 1,2-alkanediols), pyrrolidone derivatives, glycol ethers and the like.

Examples of 1,2-alkanediols include 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol and the like. .. The 1,2-alkanediols are excellent in the action of enhancing the wettability of the colored ink composition with respect to the recording medium and uniformly wetting it. When 1,2-alkanediols are contained, the content thereof can be 1% by mass or more and 20% by mass or less with respect to the total mass of the colored ink composition.

Examples of polyhydric alcohols (excluding 1,2-alkanediols) include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,6. -Hexanediol, trimethylolpropane, glycerin and the like can be mentioned. When it contains polyhydric alcohols, it can be 2% by mass or more and 30% by mass or less with respect to the total mass of the colored ink composition.

Examples of the pyrrolidone derivative include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, and 5-methyl-2-pyrrolidone. And so on. The pyrrolidone derivative acts as a good solubilizer for the resin.

Examples of glycol ethers include ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, diethylene glycol monoisohexyl ether, and triethylene glycol monoiso. Hexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoisoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether , Ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono -2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, Examples thereof include propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and tripropylene glycol monomethyl ether. These can be used alone or in admixture of two or more. Glycol ethers can control the wettability of the colored ink composition with respect to the recording medium.

The content of the organic solvent is not particularly limited, but can be, for example, 1% by mass or more and 40% by mass or less with respect to the total mass of the colored ink composition.

<Surfactant>
The colored ink composition according to this embodiment may contain a surfactant. The surfactant has a function of improving the wettability with a recording medium by reducing the surface tension of the ink. Among the surfactants, for example, acetylene glycol-based surfactants, silicon-based surfactants, fluorine-based surfactants and the like can be preferably used.

The acetylene glycol-based surfactant is not particularly limited, but for example, Surfinol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F. , 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (all product names, manufactured by Air Products and Chemicals. Inc.), Orfin B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP. 4001, EXP. 4036, EXP. 4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all product names above, manufactured by Nisshin Kagaku Kogyo Co., Ltd.), acetylenol E00, E00P, E40, E100 (all product names above, all product names, Kawaken Fine Chemical Co., Ltd.).

The silicon-based surfactant is not particularly limited, but a polysiloxane-based compound is preferably mentioned. The polysiloxane-based compound is not particularly limited, and examples thereof include polyether-modified organosiloxane. Examples of commercially available products of the polyether-modified organosiloxane include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, and BYK-348 (trade names, manufactured by BYK). , KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515 , KF-6011, KF-6012, KF-6015, KF-6017 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

As the fluorine-based surfactant, it is preferable to use a fluorine-modified polymer, and specific examples thereof include BYK-340 (manufactured by Big Chemie Japan).

When a surfactant is contained, the content thereof can be 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the colored ink composition.

<Other ingredients>
The colored ink composition used in the present embodiment may contain a pH adjuster, a preservative / fungicide, a rust preventive, a chelating agent and the like, if necessary.

1.3. Clear ink composition adhesion step 13.1. Description of Step The clear ink composition adhering step is a step of adhering the resin-containing clear ink composition to the recording area of the recording medium after the above-mentioned reaction liquid adhering step. The timing of performing the clear ink composition adhering step may be after the reaction liquid adhering step, and may be performed after the colored ink composition adhering step, simultaneously with the colored ink composition adhering step, or the colored ink composition adhering step. Either do it before. Later or at the same time is preferable, and later is more preferable, in that the effect of the present invention can be easily obtained.

Since the resin contained in the colored ink composition has extremely high reactivity with the reactant contained in the reaction solution, the resin contained in the colored ink composition reacts rapidly with the reactant, and the image quality of the recorded image is improved. It will be excellent in terms of improvement. On the other hand, due to the aggregation or thickening of the resin contained in the colored ink composition, the surface of the recorded image tends to be uneven, and the glossiness (OD) and durability of the recorded image tend to be significantly deteriorated. It was. As a result of diligent studies by the inventors of the present application, it was found that the durability of the recorded image tends to be clearly inferior when the highly reactive resin contained in the colored ink composition is used. Therefore, by overcoating the surface of the image recorded with the colored ink composition with a clear ink composition containing a resin, the glossiness (OD) and durability of the recorded image can be significantly improved. It was done. That is, according to the recording method according to the present embodiment, it was possible to record a recorded image having excellent image quality and durability.

In the clear ink composition adhesion step, droplets of the clear ink composition are ejected from the nozzle of the head for inkjet recording and adhered to the recording region to which the reaction solution and / or the colored ink composition of the recording medium described above is adhered. As a result, the recording area is overcoated. As a result, an overcoated image is formed in the recording area of the recording medium.

The maximum amount of the clear ink composition adhered to the recording region is preferably 0.5 mg / inch ² or more and 4 mg / inch ² or less. When the maximum amount of the clear ink composition adhered to the recording region is within the above range, the thickness of the overcoat can be reduced, the step on the surface of the recorded image can be eliminated, and the recording speed can be increased, which is preferable.

After the clear ink composition adhering step, a drying step of drying the clear ink composition adhering to the recording area of the recording medium may be provided. In this case, it is preferable to dry the clear ink composition so that it does not feel sticky when it comes into contact with the recording area of the recording medium. The drying step of the clear ink composition may be carried out by natural drying, but from the same viewpoint as the above-mentioned drying step of the reaction solution, it may be dried with heating. The method for heating the clear ink composition is not particularly limited, and examples thereof include the same methods as those mentioned in the above-mentioned method for heating the reaction solution. In this case, the recording speed can be increased by heating the recording medium so that the temperature is 40 ° C. or higher (preferably 45 ° C. or higher and 80 ° C. or lower).

1.3.2. Clear ink composition Next, the clear ink composition used in the clear ink composition adhering step will be described. The clear ink composition used in this embodiment contains a resin and other components.
Hereinafter, the components contained in the clear ink composition used in the present embodiment and the components that can be contained will be described in detail.

<Resin>
The resin contained in the clear ink composition improves glossiness (OD) by smoothing the unevenness of the surface of the recorded image, and improves durability by overcoating the surface of the recorded image. Has the function of.

Examples of the resin contained in the clear ink composition include urethane resin, acrylic resin, styrene acrylic resin, fluorene resin, polyolefin resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, and vinyl chloride. -Known resins such as vinyl chloride copolymer, ethylene vinyl acetate resin, and ionomer resin can be mentioned. These resins can be used alone or in combination of two or more.

The resin contained in the clear ink composition is preferably a resin having a volume of calcium acetate 0.085 mol / kg aqueous solution required for aggregating 3 mL of water containing the resin at a content of 1% by mass of 5 mL or more. , More preferably 7 mL or more, further preferably more than 7 mL, more preferably 8 mL or more, and particularly preferably 9 mL or more. The upper limit of the required volume is not particularly limited, but it is preferably 30 mL or less, more preferably 20 mL or less, still more preferably 15 mL or less, and particularly preferably 10 mL or less. Since such a resin has low reactivity with the above-mentioned reactant, the reaction (aggregation or thickening) between the resin contained in the clear ink composition and the reactant is unlikely to occur in the recording region of the recording medium. Therefore, the influence of the colored ink composition on the image quality of the recorded image can be reduced, and a smooth overcoat can be formed on the surface of the recorded image.

Further, the resin contained in the clear ink composition is 0.085 mol / kg of calcium acetate required for aggregating 3 mL of water containing the resin at a content of 1% by mass as compared with the resin contained in the colored ink composition. The volume of the aqueous solution is preferably large, more preferably 2 mL or more, further preferably 4 mL or more, and particularly preferably 5 mL or more, in terms of odor reduction and durability. Further, although not limited, it is preferably as large as 15 mL or less, more preferably as large as 13 mL or less, further preferably as large as 9 mL or less, and particularly preferably as large as 6 mL or less.

The resin having such low reactivity is not particularly limited, but may be (1) a nonionic resin, (2) a resin having an acid value of less than 5 mgKOH / g, or (3) an emulsifier. It is preferable to use a dispersed resin dispersion.

The resin contained in the clear ink composition preferably contains a resin having a glass transition temperature (Tg) of 0 ° C. or higher, and more preferably 30 ° C. or higher. The upper limit of Tg is not particularly limited, but is preferably 80 ° C. or lower, more preferably 60 ° C. or lower. By containing a resin having a glass transition temperature (Tg) of 0 ° C. or higher, a film can be easily formed and the adhesion to a recording medium is improved. Further, by performing the above-mentioned heating step at a temperature equal to or higher than Tg of the resin particles, the resin particles become fluid, so that a smooth overcoat can be formed on the surface of the recorded image. The glass transition temperature of the resin can be measured by the differential scanning calorimetry (DSC method) according to JIS K7121.

As the form of the resin, resin particles are preferable in that the above-mentioned effects can be easily obtained. The average particle size of the resin particles is preferably 200 nm or less, more preferably 10 nm or more and 150 nm or less, and particularly preferably 30 nm or more and 150 nm or less. When the average particle size of the resin particles contained in the clear ink composition is within the above range, the effect of smoothing the surface irregularities of the recorded image caused by the aggregation or thickening of the resin contained in the colored ink composition is high. Therefore, the glossiness (OD) and durability of the recorded image can be further improved. The average particle size of the resin particles can be measured by a particle size distribution measuring device based on the laser diffraction / scattering method. Examples of the particle size distribution measuring device include a particle size distribution meter (for example, "Microtrack UPA" manufactured by Nikkiso Co., Ltd.) based on a dynamic light scattering method.

The solid content of the resin is preferably 0.5% by mass or more, more preferably 0.5% by mass or more, with respect to the total mass of the clear ink composition, from the viewpoint of forming a sufficient overcoat on the surface of the recorded image. It is 1% by mass or more, particularly preferably 3% by mass or more. On the other hand, the upper limit is preferably 17% by mass or less, more preferably 15% by mass or less, still more preferably 13% by mass or less, and particularly preferably 10% by mass in terms of storage stability and ejection stability of the clear ink composition. % Or less.

<Water>
The clear ink composition used in this embodiment preferably uses water as the main solvent. This water is a component that evaporates and scatters due to drying after the clear ink composition is attached to the recording area of the recording medium. The water preferably used is the same as that described in the colored ink composition described above. The content of water contained in the clear ink composition can be, for example, 50% by mass or more with respect to the total mass of the clear ink composition.

<Organic solvent>
The clear ink composition used in this embodiment may contain an organic solvent. The organic solvent can impart functions such as improving the wettability of the clear ink composition to the recording medium, preventing drying at the ejection head, and enhancing ejection stability. As a specific example of the organic solvent, the same organic solvent as those exemplified in the above description of the colored ink composition can be used. The content of the organic solvent is not particularly limited, but can be, for example, 1% by mass or more and 40% by mass or less with respect to the total mass of the clear ink composition.

<Surfactant>
The clear ink composition used in this embodiment may contain a surfactant. The surfactant has functions such as lowering the surface tension of the reaction solution and improving the wettability with the recording medium. Among the surfactants, for example, an acetylene glycol-based surfactant, a silicon-based surfactant, and a fluorine-based surfactant can be preferably used. As specific examples of these surfactants, the same surfactants as those exemplified in the above description of the colored ink composition can be used. The content of the surfactant is not particularly limited, but can be 0.1% by mass or more and 1.5% by mass or less with respect to the total mass of the clear ink composition.

<Other ingredients>
The clear ink composition used in the present embodiment may contain a pH adjuster, a preservative / fungicide, a rust preventive, a chelating agent and the like, if necessary. Since the film formed by the clear ink composition adhering step is preferably transparent, it usually does not contain a colorant.

1.4. Physical Properties of Each Ink Composition The reaction solution, colored ink composition and clear ink composition (also referred to as “each ink composition” in the present specification) used in the present embodiment are used as inks for image quality and inkjet recording. From the viewpoint of the balance with the reliability of the above, the surface tension at 20 ° C. is preferably 20 mN / m or more and 40 mN / m, and more preferably 20 mN / m or more and 35 mN / m or less. The surface tension is measured by, for example, using an automatic surface tension meter CBVP-Z (trade name, manufactured by Kyowa Interface Science Co., Ltd.) to measure the surface tension when the platinum plate is wetted with ink in an environment of 20 ° C. It can be measured by checking.

From the same viewpoint, the viscosity of each ink composition used in the present embodiment at 20 ° C. is preferably 3 mPa · s or more and 10 mPa · s or less, and preferably 3 mPa · s or more and 8 mPa · s or less. More preferred. The viscosity can be measured by using, for example, a viscoelasticity tester MCR-300 (trade name, manufactured by Pysica) in an environment of 20 ° C.

1.5. Ink set The ink set according to the present embodiment is an ink set to be used in the above-mentioned recording method, and is characterized by including the reaction solution, the colored ink composition, and the clear ink composition. .. The description of the reaction solution, the colored ink composition, and the clear ink composition contained in the ink set according to the present embodiment will be omitted because they have been described in detail above. By carrying out the above-mentioned recording method using the ink set according to the present embodiment, it is possible to record a recorded image having excellent image quality and durability, particularly on a recording medium having low ink absorption or non-absorption. it can.

2. Recording device An example of an image recording device capable of carrying out the recording method according to the present embodiment described above will be described with reference to the drawings. The image recording device that can be used in the recording method according to the present embodiment is not limited to the following aspects. That is, in the following aspects, all the steps are continuously performed on one line (in-line), but each step may not be performed in-line but may be performed intermittently.

FIG. 1 is a diagram schematically showing an image recording device capable of carrying out the recording method according to the present embodiment. The image recording apparatus 100 includes a transport means 10 for transporting the recording medium 1, a reaction liquid adhering means 20 for adhering the reaction solution to the recording area of the recording medium, and a colored ink for adhering the colored ink composition to the recording area of the recording medium. The composition adhering means 30 and the clear ink composition adhering means 40 for adhering the clear ink composition are provided.

2.1. Transport means The transport means 10 can be composed of, for example, a roller 11. The transport means 10 may have a plurality of rollers 11. The position and number of the transporting means 10 are arbitrary as long as the recording medium 1 can be transported. The transporting means 10 may include a paper feed roll, a paper feed tray, a paper discharge roll, a paper discharge tray, various platens, and the like.

In addition, although FIG. 1 illustrates the case where the recording medium 1 is a continuous body, even if the recording medium 1 is a single sheet, the recording medium as described above can be obtained by appropriately configuring the transport means 10. Can be transported.

2.2. Reaction solution adhering means The reaction solution adhering means 20 is a means for adhering the reaction solution to the recording area of the recording medium 1 and applying the reactant contained in the reaction solution to the recording area. The reaction liquid adhering means 20 includes an inkjet recording head 21 provided with a nozzle for discharging the reaction liquid. Examples of the method of discharging the reaction solution from the nozzle of the inkjet recording head 21 include the following. Specifically, a strong electric field is applied between the nozzle and the acceleration electrode placed in front of the nozzle, and droplet-shaped reaction liquid is continuously discharged from the nozzle, and the droplet of the reaction liquid flies between the deflection electrodes. A method in which the reaction liquid is discharged in response to the recorded information signal (electrostatic suction method); the reaction liquid is forcibly generated by applying pressure to the reaction liquid with a small pump and mechanically vibrating the nozzle with a crystal transducer or the like. Method of ejecting droplets of the reaction solution; pressure and recording information signal are simultaneously applied to the reaction solution with a piezoelectric element, and droplets of the reaction solution are ejected and recorded (piezo method); resin solution is discharged with a minute electrode according to the recording information signal. Examples thereof include a method of heating and foaming to eject and record droplets of the reaction solution (thermal jet method). The reaction liquid adhering means 20 is used in the reaction liquid adhering step in the recording method according to the present embodiment.

Note that FIG. 1 shows a case where the inkjet method is used as the reaction liquid adhering means 20, but the present invention is not limited to this, and the above-mentioned methods (for example, spray coating and roll coating) may be changed to a form that can be implemented. Good.

The reaction solution adhered to the recording surface may be dried by a drying means (not shown). When the reaction solution is dried by the drying means, the drying means may be provided on the downstream side of the reaction solution adhering means and on the upstream side of the colored ink composition adhering means. The drying means is not particularly limited as long as it has a structure that promotes evaporation and scattering of the liquid medium contained in the reaction solution. For example, a means for applying heat to a recording medium, a means for blowing wind on a reaction solution, a means for combining them, and the like can be mentioned. Specifically, forced air heating, radiant heating, conductive heating, public wave drying, microwave drying and the like are preferably used.

2.3. Colored Ink Composition Adhesive Means The colored ink composition adhering means 30 is a means for forming a recorded image by adhering droplets of the colored ink composition to a recording region to which the reaction solution has adhered. The colored ink composition adhering means 30 includes an inkjet recording head 31 provided with a nozzle for ejecting the colored ink composition. The method of ejecting the colored ink composition from the nozzle of the inkjet recording head 31 is the same as the method described in the reaction liquid adhering means 20. The colored ink composition adhering means 30 is used in the colored ink composition adhering step in the recording method according to the present embodiment.

2.4. Clear Ink Composition Adhesive Means The clear ink composition adhering means 40 is a means for adhering the clear ink composition to the recording surface of the recording medium 1 to form an overcoat made of a resin. The clear ink composition adhering means 40 includes an inkjet recording head 41 provided with a nozzle for ejecting the clear ink composition. The clear ink composition adhering means 40 is used in the clear ink composition adhering step in the recording method according to the present embodiment.

In FIG. 1, the clear ink composition attaching means 40 is provided on the downstream side of the colored ink composition attaching means 30, but the colored ink composition attaching means 30 and the clear ink composition attaching means 40 are simultaneously performed. You may. That is, the colored ink composition and the clear ink composition may be ejected at the same time. Here, "discharging at the same processing" means that droplets of both inks of one ink and the other ink are ejected at a timing at which they can be mixed with each other. For example, in a serial printer, the colored ink composition and the clear ink composition may be landed on the same area in the same scan.

FIG. 1 shows a case where the inkjet method is used as the clear ink composition adhering means 40, but the present invention is not limited to this, and the above-mentioned method (for example, spray coating, roll coating) may be changed to an embodiment. Good. When the colored ink composition and the clear ink composition are ejected during the same treatment, a mixed state of the colored ink composition and the clear ink composition can be obtained in the recording area, but the resin and the reactant contained in the clear ink composition Since the reactivity of the above is low, the effect of the present invention can be sufficiently obtained.

2.5. Inkjet Recording Head When an inkjet recording head is used in the above-mentioned reaction liquid adhering means 20, colored ink composition adhering means 30, and clear ink composition adhering means 40, an inkjet recording apparatus provided with a serial type recording head. , And an inkjet recording apparatus equipped with a line-type recording head can be used.

An inkjet recording device provided with a serial-type recording head records by performing scanning (pass) a plurality of times to eject the ink composition while moving the recording head relative to a recording medium. It is something to do. In a specific example of the serial type recording head, the recording head is mounted on a carriage that moves in the width direction of the recording medium (the direction that intersects the transport direction of the recording medium), and the recording head is mounted as the carriage moves. Examples include those that eject droplets onto a recording medium when the carriage moves.

On the other hand, an inkjet recording device provided with a line-type recording head records by performing one scan (pass) for ejecting the ink composition while moving the recording head relative to the recording medium. It is something to do. Specific examples of the line-type recording head include those in which the recording head is formed wider than the width of the recording medium and the recording head ejects droplets onto the recording medium without moving.

When the clear ink composition adhering means 40 is provided after the colored ink composition adhering means 30, in the multi-pass recording method using a serial type recording head, the length of the sub-scanning performed between passes (main scanning) The clear ink composition is adhered to the unit recording area of No. 1 after the adhesion of the colored ink composition is completed. On the other hand, in the one-pass recording method using a line-type recording head, the clear ink head is arranged on the downstream side in the scanning direction from the colored ink head. Further, when the colored ink composition adhering means 30 and the clear ink composition adhering means 40 are performed at the same time, in the multipath recording method using a serial type recording head, the colored ink composition is adhered to the unit recording area. The clear ink composition is adhered even after the start of the above process and before the adhesion of the colored ink composition is completed. It is preferable that the clear ink composition adhering means 40 is provided after the colored ink composition adhering means 30 in that a recorded image excellent in image quality and durability can be obtained.

2.6. The drying means image recording apparatus 100 may be provided with the drying means 50 after the colored ink composition adhering means 30 and the clear ink composition adhering means 40. By providing the drying means 50, the liquid medium can be rapidly evaporated and scattered from the colored ink composition and the clear ink composition adhered to the recording medium, and a recorded image or an overcoat can be quickly formed. The drying means that can be adopted in the drying means 50 is the same as the means described in the above-mentioned reaction liquid adhering means 20. The image recording device 100 does not need to provide the drying means 50 when the recorded image is dried by natural drying.

3. 3. Examples Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples, but the present embodiments are not limited to these Examples.

3.1. Preparation of each ink composition <Preparation of reaction solution>
Each reaction solution (H1, H2) was prepared by mixing and stirring each component so as to have the blending ratio shown in Table 1 and then filtering with a 10 μm membrane filter. All the values in Table 1 indicate mass%, and ion-exchanged water was added so that the total mass of the reaction solution was 100% by mass.

<Preparation of colored ink composition>
Each colored ink composition (C1 to C3) was prepared by mixing and stirring each component so as to have the blending ratio shown in Table 1 and then filtering with a 10 μm membrane filter. The numerical values in Table 1 all show mass%, and ion-exchanged water was added so that the total mass of the colored ink composition was 100% by mass.

<Preparation of clear ink composition>
Each component was mixed and stirred so as to have the blending ratio shown in Table 1 to obtain each clear ink composition (CL1 to CL5). The numerical values in Table 1 all indicate mass%, and ion-exchanged water was added so that the total mass of the clear ink composition was 100% by mass.

<Resin cohesiveness test>
A 0.085 mol / kg calcium nitrate aqueous solution was added dropwise to 3 mL of the resin solution containing 1% by mass of the resin shown in Table 1 and mixed and stirred, and it was visually confirmed whether or not a precipitate was generated in the mixed solution. Table 1 also shows the volume of the 0.085 mol / kg calcium nitrate aqueous solution required for agglutination of these resins.

<Composition and physical properties of each ink composition>
The composition and physical properties of each ink composition obtained above are shown in Table 1 below.

The components described in Table 1 other than the compound names are as follows.
<Color material>
・ Black pigment (carbon black)
<Surfactant>
-Silicon surfactant (trade name "BYK-348", manufactured by Big Chemie Japan Co., Ltd.)
<Resin>
Polyethylene resin A (trade name "AQUA C ER507", produced by BYK Japan KK, average particle diameter: 50nm, Tg: 60 ℃)
Polyethylene resin B (trade name "AQUA C ER515", produced by BYK Japan KK, average particle diameter: 50nm, Tg: 60 ℃)
-Polyester resin (trade name "Elitel KT-8701", manufactured by Unitika Ltd., average particle size: 50 nm, Tg: 60 ° C.)
-Ethylene-vinyl acetate resin (trade name "Evaflex EV170", manufactured by Mitsui DuPont Polychemical Co., Ltd., average particle size: 100 nm, Tg: -30 ° C)
-Ionomer resin (trade name "Chemipearl S300", manufactured by Mitsui Chemicals, Inc., average particle size: 400 nm, Tg: 40 ° C.)

3.2. Recording method A recording medium (trade name "Cast 73", manufactured by Daio Paper Corporation, low-absorbency coated paper) was carried into PX-G930 (manufactured by Seiko Epson Corporation). Next, a test pattern of 3 cm × 3 cm was set as a recording area on the recording medium, and the reaction solution was adhered to this recording area by an inkjet method with an adhesion amount of 1 mg / inch ² (however, in Example 12, the adhesion amount was 0.4 mg / inch ^2). ) Was attached. After the adhesion is completed, the recording medium is reverse-fed, and after the time shown in Tables 2 to 4 (weight between the reaction solution and the colored ink (seconds)) is allowed, the colored ink composition is inkjet into the recording area. By the method, the adhesion amount was 6 mg / inch ² . After the adhesion was completed and the recording medium was backfed, the clear ink composition was adhered to the recording area of the recording medium by an inkjet method at an adhesion amount of 1 mg / inch ² . The recording resolution was 720 x 720 dpi, respectively. After all the adhesion was completed, the discharged recording medium was heated and dried at 50 ° C. for 20 minutes to obtain a recorded material. When each ink composition was applied using PX-G930, the surface temperature of the recording medium was set to 25 ° C.

3.3. Evaluation test <Betamura bleed image>
With respect to the recorded matter obtained as described above, Betamura bleed was visually confirmed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
◯: No unevenness inside the pattern. No bleeding around the pattern. Very good.
Δ: No unevenness inside the pattern. There is bleed around the pattern. Good.
X: There is considerable unevenness inside the pattern. Bad.

<OD>
The optical density (OD) of the recorded material obtained as described above was measured with an OD measuring device (device name "Spectrolino", manufactured by Gretag Macbeth), and evaluated based on the following evaluation criteria. In the OD measuring instrument, the higher the gloss, the higher the OD value. Therefore, the evaluation of OD can be rephrased as the evaluation of gloss.
(Evaluation criteria)
◯: 2.1 or more.
Δ: 1.9 or more and less than 2.1.
X: Less than 1.9.

<Odor>
The odor of the recorded material obtained as described above was directly sniffed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
◯: There is no odor. Very good.
Δ: A slight odor is felt. Good.
×: I feel a considerable odor. Bad.

<Durability>
The durability of the recorded material obtained as described above was evaluated using a Gakushin type friction fastness tester (device name "AB-301", manufactured by Tester Sangyo Co., Ltd.). Specifically, the recording area where the image was recorded was rubbed 100 times back and forth with a friction element attached with a white cotton cloth (JIS L 0803 compliant) under a load of 500 g.
(Evaluation criteria)
◯: The white cotton cloth is dirty, but the image is not peeled off. Very good.
Δ: Some peeling is observed in the image (less than 20%). Good.
X: The image is considerably peeled off (20% or more). Bad.

3.4. Evaluation Results Based on the above recording method and evaluation test, Examples 1 to 12 and Comparative Examples 1 to 7 were carried out. The recording methods and evaluation results of Examples 1 to 12 and Comparative Examples 1 to 7 are summarized in Tables 2 to 4 below.

According to the recording methods of Examples 1 to 12 shown in Tables 2 and 3, it was found that a recorded image having excellent image quality and durability can be recorded. In Example 7, since CL5 containing an ionomer resin having an average particle diameter of 400 nm was used as the clear ink composition, unevenness on the surface of the recorded image caused by aggregation or thickening of the resin contained in the colored ink composition. The effect of overcoating was reduced, and the glossiness (OD) was reduced. Further, in Example 12, the amount of the reaction solution adhered was 0.4 mg / inch ² , which was smaller than that of the other examples, but this tended to improve the durability. From this, it was presumed that the reactant tends to peel off the interface between the ink coating film and the recording medium, and it was found that it is preferable to minimize the amount of the reaction solution adhered.

On the other hand, as in the recording methods of Comparative Examples 1, 2 and 6 shown in Table 4, when the clear ink composition adhesion step is not performed, the overcoat is not formed, so that the glossiness (OD) and durability of the recorded image are obtained. It turned out that the sex was getting worse.

Further, when the reactivity of the resin contained in the colored ink composition with the reactant is low as in the recording methods of Comparative Examples 3 to 5 and 7 shown in Table 4, the image quality of the solid image deteriorates. It turned out to be.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes substantially the same configurations as those described in the embodiments (eg, configurations with the same function, method and result, or configurations with the same purpose and effect). The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. The present invention also includes a configuration in which a known technique is added to the configuration described in the embodiment.

1 ... Recording medium, 10 ... Conveying means, 11 ... Roller, 20 ... Reaction liquid adhering means, 30 ... Colored ink composition adhering means, 40 ... Clear ink composition adhering means, 21.31.41 ... Inkjet recording head, 50 ... Drying means, 100 ... Image recording device

Claims (14)

A reaction solution adhering step of adhering a reaction solution containing a reactant that agglutinates the colored ink composition to a recording area of a recording medium, and a reaction solution adhering step.
A step of adhering a colored ink composition containing a first resin and a coloring material to the recording region to which the reaction solution is adhered, and a clear ink composition containing a second resin. A clear ink composition adhering step for adhering objects,
The first resin is either (1) an anionic resin having an ionic functional group introduced on the surface, (2) a resin having an acid value of 5 mgKOH / g or more, and (3) a self-dispersing resin that does not depend on an emulsifier. And
The first resin and the second resin are resin particles, respectively.
As the first resin contained in the colored ink composition, trees fat particles in the resin solution 3mL of water containing only trees lipid particles 1 wt% begins to aggregate, necessary for the precipitation occurs acetate Contains a resin having a volume of 0.085 mol / kg aqueous solution of calcium of 3 mL or less.
As the second resin contained in the clear ink composition, the tree fat particles of only a resin solution 3mL of water containing 1 wt% dendritic fat particles agglomerated started, required for the precipitation occurs acetate calcium 0.085 mol / kg volume of the aqueous solution, in the first resin, starts tree fat particles agglomerated, than the volume of calcium acetate 0.085 mol / kg solution required for the precipitation occurs, 2 mL A recording method containing a larger resin . As the second resin contained in the clear ink composition, the tree fat particles of only a resin solution 3mL of water containing 1 wt% dendritic fat particles agglomerated started, required for the precipitation occurs acetate The recording method according to claim 1, which comprises a resin having a volume of an aqueous solution of 0.085 mol / kg of calcium of 5 mL or more. The recording method according to claim 1 or 2, wherein the second resin contained in the clear ink composition includes a resin having a glass transition temperature of 40 ° C. or higher. Wherein the second resin contained in the clear ink composition, the average particle diameter of the resin particles is at 100nm than 200nm or less, the first resin contained in the colored ink composition, trees
The recording method according to any one of claims 1 to 3, wherein the average particle size of the fat particles is 50 nm or less. The recording method according to any one of claims 1 to 4, wherein the adhesion of the colored ink composition is started within 20 seconds from the completion of the adhesion of the reaction solution. The recording method according to any one of claims 1 to 5, wherein the maximum amount of the reaction solution adhered to the recording area is 0.2 mg / inch ² or more and 3 mg / inch ² or less. The recording method according to any one of claims 1 to 6, wherein the reactant comprises at least one selected from the group consisting of polyvalent metal salts and organic acids. The content of the first resin contained in the colored ink composition is 0.5% by mass or more and 13% by mass or less.
The content of the second resin contained in the clear ink composition is 1% by mass or more and 17% by mass or less.
The recording method according to any one of claims 1 to 7, wherein the content of the reactant contained in the reaction solution is 0.1 mol / kg or more and 1.5 mol / kg or less. As the second resin contained in the clear ink composition, calcium acetate required for trees fat particles in the resin solution 3mL of water containing only resin particles 1 wt% begins to aggregate, precipitate generated 0.085 mol / volume kg aqueous solution, the in the first resin contained in the colored ink composition, trees fat particles starts aggregation, calcium acetate required to precipitate occurs 0.085 mol / kg The recording method according to any one of claims 1 to 8, which comprises a resin having a volume of 4 mL or more larger than the volume of the aqueous solution. The first resin and the second resin are independently any resin of acrylic resin, urethane resin, polyolefin resin, polyester resin, vinyl acetate copolymer resin, and ionomer resin, according to any one of claims 1 to 2. The recording method according to any one of claim 9. The first resin, the water containing only trees lipid particles 1 wt% of the resin solution 3mL trees fat particles starts aggregation, precipitation of calcium acetate 0.085 mol / kg solution required to generate The recording method according to any one of claims 1 to 10, which comprises a resin having a volume of 0.1 to 3 mL. The second resin, the water containing only trees lipid particles 1 wt% of the resin solution 3mL trees fat particles starts aggregation, precipitation of calcium acetate 0.085 mol / kg solution required to generate The recording method according to any one of claims 1 to 11, which comprises a resin having a volume of 5 to 30 mL. The recording method according to any one of claims 1 to 12, wherein the colored ink composition and the clear ink composition are respectively ejected from an inkjet recording head and adhered to a recording medium. An ink set comprising the reaction solution, the colored ink composition, and the clear ink composition for use in the recording method according to any one of claims 1 to 13.

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