JP2018178131A - Ink set and recording method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set that can prevent bleeding among inks and less likely causes clogging when a plurality of inks are recorded on a non-absorptive recording medium or a low-absorptive recording medium in a superimposed manner.SOLUTION: The ink set includes a reaction liquid containing a coagulant, a first ink containing a color material, and a second ink containing a color material and is used for recording on a non-absorptive recording medium or a low-absorptive recording medium. The ink set is used for imparting the reaction liquid, the first ink, and the second ink to the recording medium in a superimposed manner in the described order.SELECTED DRAWING: None

Description

  The present invention relates to an ink set and a recording method using the same.

  The ink jet recording method is a relatively simple apparatus and can record high definition images, and has been rapidly developed in various fields. For example, in Patent Document 1, for the purpose of image formation such as realization of the formation of a white image having high ink-jetting characteristics and high hiding property when forming a white image using an inkjet recording method, It is disclosed that recording is performed on an OHP sheet using an ink composition containing a titanium dioxide sol and a reaction liquid containing magnesium sulfate.

JP, 2002-103783, A

  However, when recording is performed on a non-absorbing recording medium or low-absorbing recording medium using the inkjet recording method described in Patent Document 1, a color image is recorded using a color ink on a white image. There is a problem that bleeding of color ink occurs.

  Also, in order to suppress bleeding, a method may be considered in which the recording medium is heated instead of using the reaction liquid. However, when the recording medium is heated without using the reaction liquid, high energy for heating is required, and there is a problem that clogging occurs.

  The present invention has been made to solve at least a part of the above-described problems, and when a plurality of inks are overlapped and recorded on a non-absorbing recording medium or a low-absorbing recording medium, An object of the present invention is to provide an ink set that can prevent bleeding between inks and is less likely to clog.

  The present inventors diligently studied to solve the above problems. As a result, it is found out that the above problem can be solved if the ink set includes the liquid for predetermined pretreatment separately from the plurality of inks with respect to the non-absorbing recording medium or the low-absorbing recording medium. The present invention has been completed.

That is, the present invention is as follows.
[1]
A reaction liquid containing a coagulant, a first ink containing a coloring material, and a second ink containing a coloring material,
Used for recording on non-absorbing recording media or low-absorbing recording media,
The reaction liquid, the first ink, and the second ink are applied to the recording medium in an overlapping manner in this order, and used.
Ink set.
[2]
At least one of the first ink and the second ink is a color ink containing a color colorant or a black ink containing a black colorant.
The ink set as described in the preceding paragraph [1].
[3]
The other of the first ink and the second ink is a white ink containing a white coloring material or a metallic ink containing a metallic coloring material.
The ink set as described in the preceding paragraph [2].
[4]
The coagulant includes at least one selected from the group consisting of polyvalent metal salts and organic acids.
The ink set according to any one of the above items [1] to [3].
[5]
The ratio (color material) of the number of moles of the polyvalent metal salt (unit: mol) contained in the reaction liquid to the total mass (unit: g) of the color material contained in the first ink and the second ink : A polyvalent metal salt) is from 1000: 1 to 31000: 1,
The ink set as described in the preceding paragraph [4].
[6]
Ratio (color material: organic acid) of the number of moles of the organic acid (unit: mol) contained in the reaction liquid and the total mass (unit: g) contained in the color material of the first ink and the second ink ) Is 800: 1 to 5500: 1,
The ink set as described in the preceding item [4] or [5].
[7]
The first ink is a white ink containing a white coloring material or a metallic ink containing a metallic coloring material,
The second ink is a color ink containing a color material or a black ink containing a black material.
The ink set according to any one of the above items [1] to [6].
[8]
The surface tension of the reaction solution is 55 mN / N or less at 25 ° C.
The ink set according to any one of the above items [1] to [7].
[9]
The reaction liquid further contains at least one selected from the group consisting of a component to be a receiving layer of the ink applied next to the reaction liquid, and a cationic resin.
The ink set according to any one of the above items [1] to [8].
[10]
At least one type (unit: g) selected from the group consisting of the component to be the receiving layer, which is contained in the reaction liquid, and the cationic resin, and the coloring material (unit: g) contained in the first ink The mass ratio thereof (coloring material: at least one selected from the group) is 7: 1 to 70: 1,
The ink set as described in preceding clause [9].
[11]
A recording method using the ink set according to any one of the above items [1] to [10], wherein
A reaction liquid applying step of applying a reaction liquid contained in the ink set to a non-absorbing recording medium or a low-absorbing recording medium;
A first step of applying a first ink contained in the ink set to the area to which the reaction liquid has been applied;
A second step of applying a second ink contained in the ink set to the area to which the first ink has been applied;
Recording method.
[12]
After the first step, before the second step, volatilization of volatile components contained in the reaction liquid and the first ink on the non-absorbing recording medium or the low-absorbing recording medium The amount is 95% by mass or less based on 100% by mass of the total mass of volatile components contained in the reaction liquid and the first ink before application.
The recording method as described in said [11].
[13]
The number of moles (unit: mol) of polyvalent metal salt contained in the reaction solution per unit area of the non-absorbing recording medium or the low-absorbing recording medium, the first ink, and the second ink The ratio (color material: polyvalent metal salt) to the total mass (unit: g) of the color material contained in is from 1000: 1 to 31000: 1,
The recording method according to item [11] or [12].
[14]
The number of moles (unit: mol) of the organic acid contained in the reaction liquid per unit area of the non-absorbing recording medium or the low-absorbing recording medium, and included in the first ink and the second ink The ratio (color material: organic acid) to the total mass (unit: g) of the color material to be extracted is 800: 1 to 5500: 1,
The recording method according to any one of [1] to [13].
[15]
From the component to be the receptive layer of the first ink and the second ink contained in the reaction liquid per unit area of the non-absorbing recording medium or the low-absorbing recording medium, and a cationic resin A ratio (coloring material: at least one kind selected from a group) of at least one kind of mass (unit: g) selected from the group consisting of 7: 1 to 70: 1,
The recording method according to any one of the above items [11] to [14].

FIG. 1 is a side view showing an outline of an example of an inkjet recording apparatus that can be used in the present embodiment.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as needed, but the present invention is not limited to this, Various modifications are possible without departing from the scope of the invention. In the drawings, the same elements will be denoted by the same reference signs and redundant description will be omitted. Further, the positional relationships such as upper, lower, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[Ink set]
The ink set according to the present embodiment includes a reaction liquid containing a coagulant, a first ink containing a coloring material, and a second ink containing a coloring material, and is a non-absorbing recording medium or a low-absorbing recording medium. It is used for recording on a medium (hereinafter collectively referred to as "recording medium"), and the reaction liquid and the first ink are formed on the non-absorbing recording medium or the low-absorbing recording medium. , And the second ink are applied in this order in an overlapping manner. Hereinafter, the first ink and the second ink will be collectively referred to simply as "ink".

[Reaction solution]
The reaction solution contains a coagulant. By using such a reaction liquid, it is possible to obtain a high-quality recorded material without heating the recording medium, and to prevent clogging of the nozzle due to the nozzle drying or the like due to the heating of the recording medium. be able to. Specifically, by including a coagulant, the pigment contained in the first ink and the pigment contained in the second ink can be coagulated without heating, and bleeding of the second ink can be prevented. As a result, it becomes possible to prevent the solid unevenness of the first ink, and a high quality recorded matter can be obtained.

(Flocculant)
The aggregating agent is not particularly limited, but preferably contains, for example, at least one selected from the group consisting of polyvalent metal salts and organic acids.

(Polyvalent metal salt)
The polyvalent metal salt is not particularly limited, but for example, a polyvalent metal salt of an inorganic acid or a polyvalent metal salt of an organic acid is preferable. Such polyvalent metal salts are not particularly limited, and examples thereof include alkaline earth metals of group 2 of the periodic table (for example, magnesium, calcium), and transition metals of group 3 of the periodic table (for example, lanthanum) Mention may be made of the salts of Group 13 earth metals of the Periodic Table (for example aluminum), lanthanides (for example neodymium). As salts of these polyvalent metals, carboxylates (formic acid, acetic acid, benzoate and the like), sulfates, nitrates, chlorides and thiocyanates are preferable. Among them, calcium salts or magnesium salts of carboxylic acids (formic acid, acetic acid, benzoate and the like), calcium salts or magnesium salts of sulfuric acid, calcium salts or magnesium salts of nitric acid, calcium chloride, magnesium chloride, and thiocyanate are preferable. Calcium or magnesium salts may be mentioned. The polyvalent metal and the salt constituting the polyvalent metal salt may be any combination, or may be a hydrate. In addition, a polyvalent metal salt may be used individually by 1 type, and may use 2 or more types together.

  The content of the polyvalent metal salt is preferably 0.5 to 5% by mass, more preferably 0.5 to 4% by mass, and still more preferably 1 to 4% by mass with respect to 100% by mass of the total mass of the reaction solution. . When the content of the polyvalent metal salt is in the above range, the bleeding resistance of the obtained recorded matter tends to be more excellent.

(Organic acid)
The organic acid is not particularly limited, and examples thereof include phosphoric acid, oxalic acid, malonic acid, succinic acid, citric acid and acetic acid. Among these, monovalent or divalent or higher carboxylic acids are preferable. By containing such a carboxylic acid, it tends to be more excellent in the bleed resistance of the obtained recording material. In addition, an organic acid may be used individually by 1 type, and may use 2 or more types together. The organic acid may also be in the form of a salt. Although it does not specifically limit as an organic acid salt, For example, the salt of the said organic acid (However, it does not overlap with the said polyvalent metal salt.) Is mentioned. Although it does not specifically limit as a salt of the said organic acid, For example, sodium acetate etc. are mentioned. In addition, an organic acid salt may be used individually by 1 type, and may use 2 or more types together.

  1-15 mass% is preferable with respect to 100 mass% of total mass of a reaction liquid, as for content of an organic acid, 1-14 mass% is more preferable, and 1-7 mass% is further more preferable. When the content of the organic acid is in the above range, the resistance to bleeding of a recorded material obtained tends to be more excellent.

  The reaction liquid is at least one selected from the group consisting of a component (hereinafter, also simply referred to as “receiving layer component”) to be a receiving layer of at least one of the first ink and the second ink, and a cationic resin It is preferable to include.

(Component to be a receptive layer of at least one of the first ink and the second ink)
When the reaction solution contains a receptor layer component, it tends to be more excellent in bleed resistance and color developability of the obtained recording material. The receptor layer component is not particularly limited, and examples thereof include solid particles in a liquid, including inorganic particles and solid resin particles in a liquid. Examples of such particles include cationic particles, nonionic particles, and anionic particles. Among these, one in which a gap remains between fine particles in a state of being attached to a recording medium to form a coating film is preferable. The "gap" refers to a void in a state in which the coating film of the reaction liquid is dried. When the reaction liquid is applied to the recording medium to form a coating film, a gap is formed in the coating film by the component to be the receiving layer, and at least the ink applied next to the reaction liquid is absorbed in the gap, thereby bleeding. Is more preferable in that The component to be the receptive layer is usually at least a component to be the receptive layer of the first ink, and may be the receptive layer of the second ink to be applied next.

  When the particles are cationic, they have an effect of forming a layer that receives the first ink and the second ink and imparting cohesion. The cationic particles are not particularly limited, and examples thereof include Snowtec ST-AK (trade name of Nissan Chemical Industries, Ltd.).

  The particles are anionic or nonionic to form a layer that receives the first ink or the second ink. The anionic particles or the nonionic particles are not particularly limited, and examples thereof include anionic colloidal silica. As a commercial item, Snowtex ZL (brand name by Nissan Chemical Industries, Ltd.) is mentioned, for example.

  0.1-10 mass% is preferable with respect to 100 mass% of total mass of a reaction liquid, as for content of a receiving layer component, 0.1-6 mass% is more preferable. When the content of the receptive layer component is in the above range, it tends to be more excellent in bleed resistance and color developability of the obtained recording material. The receptor layer components may be used alone or in combination of two or more.

(Cationic resin)
When the reaction liquid contains a cationic resin, it tends to be more excellent in bleed resistance and color developability of the obtained recording material. Although it does not specifically limit as cationic resin, For example, resin which shows a dispersed state in liquids, such as resin soluble in a reaction liquid and a resin emulsion, is mentioned. The cationic resin acts as an adjunct to the coagulant more than the coagulant because the interaction with the pigment contained in the first ink and the second ink is relatively weak compared to the coagulant described above. A resin soluble in the reaction solution is preferred in that the interaction is excellent.

  The resin soluble in the reaction solution is not particularly limited, and examples thereof include amine resins, such as polyallylamine and polyallylamine derivatives.

  The resin emulsion is not particularly limited, and examples thereof include polyolefin resins, urethane resins, acrylic resins, and polyester resins. For example, a resin emulsion that may be contained in the ink described later is mentioned, and as a commercial product, for example, Arrow Base CD-1200 (trade name of UNITIKA, a polyolefin-based resin) is mentioned, which is preferable.

  0.1-10 mass% is preferable with respect to 100 mass% of total mass of a reaction liquid, and, as for content of cationic resin, 0.1-6 mass% is more preferable. When the content of the cationic resin is in the above-mentioned range, it tends to be more excellent due to the bleeding resistance and the coloring property of the recording material obtained. The cationic resin may be used alone or in combination of two or more.

  In addition to the above, the reaction solution can contain a solvent, a surfactant, and the like.

〔solvent〕
The reaction liquid in the present embodiment preferably further contains a solvent. The solvent is not particularly limited, and for example, an organic solvent or water can be used.

  Examples of water include pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, and distilled water, and water from which ionic impurities have been removed as much as possible, such as ultrapure water. In addition, if water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the reaction solution is stored for a long time. This tends to further improve storage stability.

  80-95 mass parts is preferable with respect to 100 mass parts of reaction liquids, and, as for content of water, 85-95 mass parts is more preferable. When the water content is in the above range, the viscosity tends to be lower.

  As the organic solvent, a volatile water-soluble organic solvent is more preferable. The organic solvent is not particularly limited. Specifically, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1, 2 -Pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol Mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monobutyl Ether, diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono- n-Butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol Butylme Ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, Alcohols or glycols such as tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, Sulfolane and 1,1,3,3-tetramethylurea can be mentioned.

  The organic solvents may be used alone or in combination of two or more. The content of the organic solvent is not particularly limited, and can be appropriately determined as necessary. Among these, it is preferable to use one or more selected from the group consisting of 1,2-hexanediol, triethylene glycol monobutyl ether, and dipropylene glycol monopropyl ether.

  The content of the organic solvent is preferably 1 to 10% by mass with respect to 100% by mass of the total mass of the reaction solution.

[Surfactant]
The reaction liquid used in the present embodiment preferably contains a surfactant. The surfactant is not particularly limited, but is preferably at least one selected from the group consisting of, for example, an acetylene glycol surfactant and a polysiloxane surfactant.

  Among these, polysiloxane-based surfactants are more preferable because the solubility in the reaction solution is increased and foreign matter is less likely to be generated in the reaction solution.

  The above-mentioned acetylene glycol surfactant is not particularly limited, and, for example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl- Alkylene oxide adducts of 5-decyne-4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol One or more of them are preferred. These are E series (trade names of Air Products Japan, Inc.) such as Olfin 104 series and Olfin E1010, Olfin PD-002W, Surfynol 465 and Surfynol 61 (Nissin Chemical Industries, Ltd. They are available as commercial products such as Chemical Industry CO., Ltd.).

  The polysiloxane surfactant is not particularly limited, and examples thereof include BYK-347 and BYK-348 (trade names of BYK Japan KK).

  As for content of said surfactant, 0.1-3 mass% is preferable with respect to 100 mass% of total mass of a reaction liquid.

  At 25 ° C., the surface tension of the reaction solution is preferably 55 mN / N or less, more preferably 40 mN / N or less. When the surface tension is within the above range, the reaction liquid can be uniformly applied when recording is performed on the recording medium. The lower limit of the surface tension of the reaction solution is not particularly limited, but is preferably 1 mN / N or more at 25 ° C. The surface tension can be measured by the method described in the examples.

[First ink]
The first ink contains a colorant. The content of the coloring material in the first ink is preferably 15 to 2% by mass, and more preferably 13 to 3% by mass with respect to 100% by mass of the total mass of the first ink. When the content of the coloring material is in the above-mentioned range, it tends to be more excellent due to the bleeding resistance and the coloring property of the obtained recording material.

[Second ink]
The second ink contains a colorant. The content of the colorant in the second ink is preferably 15 to 2% by mass, and more preferably 13 to 3% by mass, with respect to 100% by mass of the total mass of the second ink. When the content of the coloring material is in the above-mentioned range, it tends to be more excellent due to the bleeding resistance and the coloring property of the obtained recording material.

[Color material]
The colorants that may be included in the first ink and the second ink will be described below. Each of the first ink and the second ink may contain one or two or more coloring materials. The coloring material may be a dye or a pigment.

  Examples of the black colorant used in the black ink include carbon black and are not particularly limited. 2300, no. 900, MCF 88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200 B and the like (above, Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700 and so on (above, Columbia Carbon), Rega1 400R, Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400 etc. (made by CABOT JAPAN K. K.), Color Black FW1 , Color B lack FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140 U, Special Black 6, Special Black 5, Special Black 4A , Special Black 4 (manufactured by Degussa).

  The color material used for the white ink (white ink) is not particularly limited. I. Pigment white 6, 18, 21 may be mentioned. Other pigments used for white ink include sulfates of alkaline earth metals such as barium sulfate, carbonates of alkaline earth metals such as calcium carbonate, and silicas such as finely divided silicic acid and synthetic silicates, And metal compounds such as calcium silicate, alumina, alumina hydrate, titanium dioxide, and zinc oxide, and talc and clay.

  The colorant used in the yellow ink is not particularly limited. I. Pigment yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 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, 154, 154, 154, 167, 172, 180 can be mentioned.

  The colorant used in the magenta ink is not particularly limited. 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, or C.I. I. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

  The colorant used for cyan ink is not particularly limited. I. Pigment blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat Blue 4, 60 can be mentioned.

  In addition, color materials other than magenta, cyan, and yellow are not particularly limited. I. Pigment green 7, 10, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I. Pigment orange 1,2,5,7,13,14,15,16,24,34,36,38,40,43,63.

  A metallic pigment is mentioned as a metallic color material used for metallic ink, a metal particulate can be used, aluminum, an aluminum alloy, silver etc. is mentioned as a metal. The metallic ink is an ink in which the pattern formed on the recording medium has a metallic gloss, and the metallic pigment is a pigment exhibiting a metallic gloss.

  It is preferable that at least one of the first ink and the second ink is a color ink containing a color colorant or a black ink containing a black colorant. Further, one of the first ink and the second ink is a color ink containing a color coloring material or a black ink containing a black coloring material, and the other of the first ink and the second ink is a white ink containing a white coloring material. It is more preferable that With such an ink set, when recorded on a non-absorptive recording medium or a low-absorptive recording medium, color development can be obtained with respect to recording media other than white. For example, transparent, color and metallic media are preferably used.

  It is preferable that the first ink is a white ink containing a white coloring material, and the second ink is a color ink containing a color coloring material or a black ink containing a black coloring material. With such an ink set, when recorded on a non-absorptive recording medium or a low-absorptive recording medium, color development can be obtained with respect to recording media other than white. For example, transparent, color and metallic media are preferably used.

  The ratio A of the number of moles of flocculant (unit: mol) contained in the reaction liquid to the total mass (unit: g) of the coloring material contained in the first ink and the second ink is 100: 1 to 5000: 1. Are preferred, and 500: 1 to 4000: 1 are more preferred. By setting the ratio A to 100: 1 or more, it is possible to prevent the deposition of the reaction solution, the occurrence of white turbidity, stickiness and odor due to the reaction solution. Further, when the ratio A is 5000: 1 or less, bleeding at the time of ink superposition can be suppressed.

  The ratio B of the number of moles of polyvalent metal salt contained in the reaction liquid (unit: mol) to the total mass (unit: g) of the coloring material contained in the first ink and the second ink is 300: 1 to 5000 : 1: 1 is preferable and 500: 1-5000: 1 are more preferable. By setting the ratio B to 300: 1 or more, it is possible to prevent the precipitation of the polyvalent metal salt, the occurrence of cloudiness, stickiness and odor due to the polyvalent metal salt. In addition, when the ratio B is 5000: 1 or less, it is possible to suppress bleeding at the time of ink superposition.

  The ratio C of the number of moles of organic acid contained in the reaction liquid (unit: mol) to the total mass (unit: g) contained in the coloring materials of the first ink and the second ink is 100: 1 to 800: 1. Is preferred, and 100: 1 to 700: 1 is more preferred. By setting the ratio C to 100: 1 or more, it is possible to prevent the deposition of the organic acid, the white turbidity due to the organic acid, the stickiness, and the generation of an odor. In addition, when the ratio C is 800: 1 or less, bleeding at the time of ink superposition can be suppressed.

  At least one mass (unit: g) selected from the group consisting of a receptor layer component and a cationic resin contained in the reaction liquid, and the mass (unit: g) of the coloring material contained in the first ink The ratio D is preferably 1: 1 to 10: 1, more preferably 1: 1 to 5: 1. When the ratio D is 1: 1 or more (the former), the bleeding tends to be further suppressed in order to further assist the function of suppressing the bleeding of the coagulant. In addition, when the ratio D is 10: 1 or less (the former), the storage stability of the reaction liquid and the clogging reliability in the case of coating by inkjet tend to be more excellent.

  As apparent from Table 2, in the above-mentioned respective ratios, the ratio A is the ratio (colorant: flocculant), the ratio B is the ratio (colorant: polyvalent metal salt), and the ratio C is the ratio (colorant: organic acid The ratio D is a ratio (color material: at least one selected from the above group), and the ratios A to C are in the reaction liquid of unit mass, the first ink of unit mass, and the second ink of unit mass The ratio D is for the unit mass of the reaction liquid and the unit mass of the first ink.

  When a pigment is used as the coloring material, the pigment is a self-dispersion type surface having a hydrophilic group introduced as a pigment dispersion obtained by dispersing it in water with a dispersant, or using a chemical reaction on the surface of pigment particles. It is preferable to add to the ink as a pigment dispersion obtained by dispersing the treated pigment in water or obtained by dispersing a polymer-coated pigment in water.

  The dispersant is not particularly limited. For example, polymer dispersants (gum, gelatin, casein, proteins of albumin, gum arabic, natural gums of tragacanth gum, glucosides of saponin, alginic acid and propylene glycol ester, alginic acid Triethanolamine, alginic acid fermented ammonium alginate methylcellulose, carboxymethylcellulose, cellulose derivative of ethylhydroxycellulose, polyvinyl alcohols, polypyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer Polymer, vinyl acetate-acrylic acid ester copolymer, acrylic resin of acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene -Methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-acrylic resin of styrene-m-methylstyrene-acrylic acid copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride Copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-fatty acid vinyl ethylene copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-croton copolymer, acetic acid Vinyl acetate copolymers of vinyl-acrylic acid copolymers and salts thereof and surfactants (various anionic surfactants, nonionic surfactants, amphoteric surfactants) can be used.

  The surface-treated pigment of self-dispersion type into which a hydrophilic group is introduced is capable of being dispersed or dissolved in water without a dispersant by surface treatment such that a carboxyl group and its salt are directly bonded to the surface of the pigment It is. Specifically, it is obtained by grafting a functional group or a molecule containing a functional group to the surface of a pigment by physical treatment of vacuum plasma or chemical treatment using an oxidant of sodium hypochlorite or ozone. Can. The functional group to be grafted to one pigment particle may be single or plural. The kind of the functional group to be grafted and the degree thereof may be appropriately determined in consideration of the dispersion stability in the ink, the color density, and the drying property on the front surface of the ink jet head.

  Further, the pigment coated with the above-mentioned polymer is not particularly limited, but for example, after dispersing the pigment using a dispersant having a polymerizable group, a monomer copolymerizable with the dispersant (copolymerizable monomer) And an optical radical polymerization initiator to obtain emulsion polymerization in water. Among these polymers, monomers and oligomers having at least one selected from the group consisting of acryloyl group, methacryloyl group, vinyl group, and allyl group as a double bond, according to a known polymerization method using a photo radical polymerization initiator Those polymerized are preferably usable. The above-mentioned emulsion polymerization can be performed by a general method, and the polymerization proceeds by free radicals generated by thermal decomposition of a water-soluble photo-radical polymerization initiator in the presence of an emulsifier.

  The pigment and the dispersant that constitute the pigment dispersion may be used alone or in combination of two or more.

[Resin emulsion]
When the ink used in the present embodiment contains a pigment as a coloring material, it is preferable to further contain a resin emulsion. By using the resin emulsion, the resins in the resin emulsion, the resin and the pigment mutually fuse with each other as the ink is dried, and the pigment is fixed to the recording medium, so that the image portion of the recording material is The abrasion resistance and the adhesion can be further improved. Among resin emulsions, urethane resin emulsions and acrylic resin emulsions are preferable, and urethane resin emulsions are more preferable. As a result, the fixability of the ink becomes excellent, so both the abrasion resistance and the adhesion of the recorded matter become excellent.

  When the resin emulsion is contained in the ink, the resin emulsion forms a resin film on the recording medium, thereby sufficiently fixing the ink on the recording medium to make the abrasion resistance of the recording material excellent. . Therefore, it is preferable that the resin emulsion contains a thermoplastic resin. In particular, a urethane resin emulsion has a high degree of freedom in design, so it is easy to obtain desired film properties.

  In addition, anionic resin emulsions are also preferred. Although it does not specifically limit as resin contained in the said anionic resin emulsion, For example, (meth) acrylic acid, (meth) acrylic acid ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, Included are homopolymers or copolymers of vinyl alcohol, vinyl ether, vinyl pyrrolidone, vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride, fluororesins, and natural resins. Among them, at least one selected from the group consisting of (meth) acrylic resins and styrene- (meth) acrylic acid copolymer resins is preferable, and is selected from the group consisting of acrylic resins and styrene-acrylic acid copolymer resins At least one is more preferable, and a styrene-acrylic acid copolymer resin is more preferable. The above-mentioned copolymer may be in any form among a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  As a resin emulsion, what is obtained by a well-known material and manufacturing method may be used, and a commercial item may be used. The commercially available product is not particularly limited. For example, Movinyl 966A (trade name of acrylic resin emulsion manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Microgel E-1002, Microgel E- 5002 (trade name, manufactured by Nippon Paint Co., Ltd.), Bon coat 4001, Bon coat 5454 (trade name, manufactured by DIC), SAE 1014 (trade name, manufactured by Zeon Corporation), Sybinol SK-200 (trade name, manufactured by SAIDEN CHEMICAL INDUSTRY CO., LTD.), Joncryl 7100, Joncryl 390, Joncryl 711, Joncryl 511, Joncryl 7001, Joncryl 632, Joncryl 741, John Krill 450, John Krill 840, John Krill 62 J, Joncrill 74J, Joncryl HRC-1645J, Joncryl 734, Joncryl 852, Joncryl 7600, Joncryl 775, Joncryl 537J, Joncryl 1535, Joncryl PDX-7630A, Joncryl 352J, Joncryl 352D, Joncryl PDX -7145, Joncryl 538J, Joncryl 7640, Joncryl 7641, Joncryl 631, Joncryl 790, Joncryl 780, Joncryl 7610 (trade name, manufactured by BASF), NK binder R-5HN (Shin-Nakamura Chemical Co., Ltd.) (Trade name, acrylic resin emulsion, solid content 44%). Among these, Movinyl 966A, which is an acrylic resin emulsion, is preferable in order to sufficiently satisfy the preferable physical properties of the resin emulsion described above.

  The resin emulsion may be used alone or in combination of two or more.

  3-15 mass% is preferable with respect to 100 mass% of total mass of each ink, as for content of resin of a resin emulsion, 7-14 mass% is more preferable, and 8-13 mass% is more preferable. By being within the above range, the adhesion and abrasion resistance of the recorded matter tend to be more excellent, and the long-term storage stability of the ink is excellent, and in particular, the viscosity can be reduced. It is in.

〔solvent〕
The ink in the present embodiment preferably further contains a solvent. The solvent is not particularly limited, and for example, an organic solvent or water can be used.

  Examples of water include pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, and distilled water, and water from which ionic impurities have been removed as much as possible, such as ultrapure water. In addition, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, the generation of mold and bacteria can be prevented when the ink is stored for a long time. This tends to further improve storage stability.

  As the organic solvent, a volatile water-soluble organic solvent is more preferable. The organic solvent is not particularly limited. Specifically, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1, 2 -Pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol Mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monobutyl Ether, diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono- n-Butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol Butylme Ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, Alcohols or glycols such as tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, Sulfolane and 1,1,3,3-tetramethylurea can be mentioned.

  The organic solvents may be used alone or in combination of two or more. The content of the organic solvent is not particularly limited, and can be appropriately determined as necessary. Among these, it is preferable to use one or more selected from the group consisting of 1,2-hexanediol, triethylene glycol monobutyl ether, and dipropylene glycol monopropyl ether.

[Surfactant]
The ink used in the present embodiment preferably contains a surfactant. The surfactant is not particularly limited, but is preferably at least one selected from the group consisting of, for example, an acetylene glycol surfactant and a polysiloxane surfactant. When the ink contains these surfactants, the drying property of the ink attached to the recording medium is further improved, and high speed recording is possible.

  Among these, polysiloxane-based surfactants are more preferable because the solubility in the ink is increased and foreign matter is less likely to be generated in the ink.

  The above-mentioned acetylene glycol surfactant is not particularly limited, and, for example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl- Alkylene oxide adducts of 5-decyne-4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol One or more of them are preferred. These are E series (trade names of Air Products Japan, Inc.) such as Olfin 104 series and Olfin E1010, Olfin PD-002W, Surfynol 465 and Surfynol 61 (Nissin Chemical Industries, Ltd. They are available as commercial products such as Chemical Industry CO., Ltd.).

  The polysiloxane surfactant is not particularly limited, and examples thereof include BYK-347 and BYK-348 (trade names of BYK Japan KK).

[Moisturizer]
The ink used in the present embodiment preferably further includes a humectant (humectant). The humectant can be used without particular limitation as long as it is generally used for inkjet ink. The boiling point of the humectant is preferably 180 ° C. or more, more preferably 200 ° C. or more. When the boiling point is in the above range, the ink can be provided with good water retention and wettability.

  Specific examples of the high boiling point humectant include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1 , 3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycol having a number average molecular weight of 2000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, glycerin, mesoerythritol, and Pentaerythritol is mentioned.

  The humectant may be used alone or in combination of two or more. When the ink contains a high boiling point humectant, it is possible to obtain an ink capable of maintaining fluidity and redispersion for a long time even when the pigment ink is left in contact with air in an open state. Furthermore, such an ink is less likely to cause clogging of the nozzles during resumption during printing using the printing apparatus or after interruption, so that the ink ejection stability is excellent.

[Other ingredients]
In order to maintain the storage stability and the ejection stability from the head favorably, the ink used in this embodiment improves the clogging, or prevents the deterioration of the ink, solubilizer, viscosity modifier, pH Various additives such as modifiers, antioxidants, preservatives, fungicides, corrosion inhibitors, and chelating agents for capturing metal ions that affect dispersion can be added as appropriate. It is preferable from the viewpoint of safety that the ink used in the present embodiment is a water-based ink containing the largest amount of water among volatile components.

[Recording medium]
The ink set according to the present embodiment is used for recording on a non-absorbing recording medium or a low-absorbing recording medium. Absorbable recording media are inferior in water resistance and abrasion resistance, etc., and in the case of an absorbent recording medium constructed by providing an ink receiving layer on the surface, the cost may be high, whereas non-absorbing The recording medium or the low absorption recording medium is superior in cost and cost to the absorbent recording medium constructed by providing the ink receiving layer on the surface with water resistance, abrasion resistance, and low absorption, and further, The more non-absorbing, the more likely bleeding occurs, and it becomes more difficult to simultaneously achieve both bleeding and printing speed, so it is advantageous to use the ink set according to this embodiment, and non-absorbing recording media are more advantageous. is there.

Here, "low absorbing recording medium" or "non-absorbing recording medium", water absorption from the contact start to 30msec in Bristow (Bristow) method refers to a recording medium which is a 10 mL / m ² or less . The Bristow method is most widely used as a method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper and Pulp Technical Association (JAPAN TAPPI). For the details of the test method, the standard No. 1 of "JAPAN TAPPI Paper Pulp Test Method 2000 Edition". 51 "Paper and board-liquid absorption test method-Bristow method".

  The non-absorbing recording medium or the low-absorbing recording medium can also be classified by the wettability of the recording surface to water. For example, a 0.5 μL water droplet is dropped on the recording surface of the recording medium, and recording is performed by measuring the reduction rate of the contact angle (comparison of the contact angle at 0.5 ms after landing and the contact angle at 5 seconds) The media can be characterized. More specifically, as a property of the recording medium, the non-absorbing property of the "non-absorbing recording medium" indicates that the reduction ratio is less than 1%, and the low absorbing property of the "low-absorbing recording medium" The term "sex" means that the above-mentioned reduction rate is 1% or more and less than 5%. Moreover, absorbency points out that the said fall rate is 5% or more. The contact angle can be measured using a portable contact angle meter PCA-1 (manufactured by Kyowa Interface Science Co., Ltd.) or the like.

The low absorption recording medium is not particularly limited, and examples thereof include a coated paper provided with a coating layer for receiving an oil-based ink on the surface. Specifically, it is a paper which is coated with a paint on the surface to enhance the appearance and smoothness, and is classified as a coated paper for printing in the "Production Movement Statistical Classification" of the Ministry of Economy, Trade and Industry. Examples of the paint include those prepared by mixing a white pigment which is an inorganic compound such as clay (kaolin) and calcium carbonate and an adhesive (binder) such as starch. The application amount of the paint is preferably about 10 to 40 g / m ² . The coated paper is not particularly limited, and examples thereof include recording paper such as art paper, coated paper, matte paper and the like.

  The non-absorbing recording medium is not particularly limited. For example, a plastic film not having an ink absorbing layer, a substrate on which a plastic is coated on a substrate such as paper, or a plastic film is adhered Etc. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, polypropylene and polyacryl.

  Furthermore, in addition to the above-described recording medium, a plate of metals such as iron, silver, copper, and aluminum, and a non-ink-absorbing or low-absorbing recording medium such as glass can also be used.

〔Recording method〕
In the recording method according to the present embodiment, a reaction liquid applying step of applying a reaction liquid on a non-absorbing recording medium or a low-absorbing recording medium using the above ink set, and a first ink from above the reaction liquid And a second step of applying a second ink from above the first ink.

  FIG. 1 is a side view showing an outline of an example of an inkjet recording apparatus 1 that can be used in the present embodiment. As shown in FIG. 1, the inkjet recording apparatus 1 includes a recording medium feeding unit 10, a conveyance unit 20, a recording unit 30, a drying device 90, and a discharge unit 70. The inkjet recording apparatus 1 also includes a pre-heater (not shown), and the recording medium F may be heated from the beginning.

  Among them, the drying device 90 includes a first drying unit 40 which performs a drying process of the recording medium, and a second drying unit 50 which dries the recorded matter obtained by the recording method according to the present embodiment.

  Further, the feeding unit 10 is provided so as to be able to feed the recording medium F to the conveyance unit 20. Specifically, the feeding unit 10 has a roll medium holder 11, and the roll medium holder 11 holds the recording medium F. Then, by rotating the recording medium F, the recording medium F can be fed to the conveyance section 20 on the downstream side in the feeding direction Y. The recording medium F is not limited to the roll shape.

  Further, the transport unit 20 is provided so as to be able to transport the recording medium F sent from the feeding unit 10 to the recording unit 30. Specifically, the transport unit 20 includes the first feed roller 21 and is configured to be able to further transport the fed recording medium F to the recording unit 30 on the downstream side in the transport direction Y.

  In addition, the recording unit 30 is provided so as to apply a reaction liquid to the recording medium F sent from the conveyance unit 20 and to discharge the ink for recording. Specifically, the recording unit 30 includes a head 31 that performs a reaction liquid application process, a head 32 that performs a first process, a recording head 33 that performs a second process, and a platen 34 as a medium support unit. . The method of applying the reaction liquid and the ink is not limited to inkjet, and in particular, the reaction liquid may be applied by roller coating, spray coating, or the like. The ink jet is preferable in that the application position and the application amount can be applied with high accuracy to the necessary area.

  Among these, the platen 34 is provided so as to support the recording medium F from the back side. Further, the platen 34 is provided with a first drying unit 40 for drying the reaction liquid applied to the recording medium F and the ink discharged to the recording medium F. Furthermore, a second feed roller 43 is provided downstream of the platen 34 in the feed direction Y. The second feed roller 43 is configured to be able to feed the recorded recording medium F to the second drying unit 50 on the downstream side in the feed direction Y.

  The second drying unit 50 is configured to be able to further dry the reaction liquid applied to the recording medium F and the ink discharged to the recording medium F. Further, a third feed roller 65 is provided near the outlet 64 of the second drying unit 50. The third feed roller 65 is disposed to be in contact with the back surface of the recording medium F, and is configured to be able to send the recording medium F to the discharge unit 70 on the downstream side in the feeding direction Y.

  Furthermore, the discharge unit 70 is provided so that the recording medium F sent from the second drying unit 50 can be further sent to the downstream side in the feed direction Y and discharged to the outside of the inkjet recording apparatus 1. Specifically, the discharge unit 70 includes a fourth feed roller 71, a fifth feed roller 72, a sixth feed roller 73, a seventh feed roller 74, and a winding roller 75. Among them, the fourth feed roller 71 and the fifth feed roller 72 are disposed in contact with the surface of the recording medium F. The sixth feed roller 73 and the seventh feed roller 74 are disposed to form a roller pair. The recording medium F discharged by the sixth feed roller 73 and the seventh feed roller 74 is provided so as to be taken up by the take-up roller 75.

[Reaction liquid application process]
The reaction liquid applying step is a step of applying the reaction liquid on the non-absorbing recording medium or the low absorbing recording medium. The application means is not particularly limited, and for example, roller application, spray application, and inkjet application can be used. The method may further include the step of drying at least a part of the reaction liquid applied to the recording medium during or after the reaction liquid applying step.

Application amount to the recording medium of the reaction solution is preferably ^{1~10mg / inch 2, 1~5mg / inch} 2 is preferable. When the application amount of the reaction liquid is in the above range, the resistance to bleeding of the obtained recording material tends to be excellent.

The amount of the coagulant to be applied to the recording medium is preferably 0.5 × 10 ^-4 to 15 × 10 ^-4 mmol / inch ² (50 to 1500 nmol / inch ² ), and 0.65 × 10 ^-4 mmol / inch ² or more is more preferable, 1 × 10 ⁻⁴ mmol / inch ² or more is more preferable, 1.5 × 10 ⁻⁴ mmol / inch ² or more is more preferable, 2 × 10 ⁻⁴ mmol / inch ² or more is more preferable , 3 × 10 ⁻⁴ mmol / inch ² or more is particularly preferable. Further, the application amount is preferably 10.8 × 10 ⁻⁴ mmol / inch ² or less, more preferably 10 × 10 ⁻⁴ mmol / inch ² or less, and particularly preferably 5 × 10 ⁻⁴ mmol / inch ² or less. When the application amount of the coagulant is as described above, the image quality and the like of the recorded matter are further excellent, and it is preferable in that the values of ratio F to ratio H described later can be easily obtained. The application amounts of the reaction liquid and the coagulant are the application amounts of the reaction liquid and the coagulant per unit area in a region where the first ink and the second ink are applied in an overlapping manner.

[First step]
The first step is a step of applying a first ink from above the reaction liquid. At this time, since the reaction liquid and the first ink directly react, aggregation of the first ink is possible quickly, and the reaction liquid may not be completely dried. Since the reaction liquid may not be completely dried or the reaction liquid may not be dried, the application of the first ink can be started quickly, and the speeding up of the recording speed can be achieved. The method may further include the step of drying at least a part of the reaction liquid and the first ink applied to the recording medium during or after the first step.

2-20 mg / inch ² is preferable and, as for the application amount of the 1st ink in a 1st process, 15-5 mg / inch ² is more preferable. When the application amount of the first ink is in the above range, the obtained recording material tends to be more excellent in bleed resistance, clogging reliability, and stickiness.

[The second step]
The second step is a step of applying a second ink from above the first ink. At this time, the reaction liquid and the first ink may not be completely dried. By applying the second ink in a state in which the first ink is not completely dried, the reaction liquid and the second ink can react even from above the first ink, and the reaction occurs. Even if the liquid and the first ink are not completely dried, the second ink can be applied while suppressing the bleeding, and the speeding up of the recording speed can be achieved. Before the second step, it may have the step of drying at least a part of the reaction liquid and the first ink applied to the recording medium, and it is a step of drying the part without completely drying it. Is preferred. In addition, it may have a step of drying the second ink applied to the recording medium during or after the second step.

Providing amount of the second ink in the second step is preferably ^{2~20mg / inch 2, 15~5mg / inch} 2 is preferable. When the application amount of the first ink is in the above range, the obtained recording material tends to be more excellent in bleed resistance, clogging reliability, and stickiness.

In the first and second steps, the total application amount (total mass) per unit area of the coloring material contained in the first ink and the second ink in the area where the first ink and the second ink are applied in an overlapping manner is 0.5 to 3 mg / inch ² is preferable, 1 mg / inch ² or more is preferable, 1.5 mg / inch ² or more is more preferable, and 2.5 mg / inch ² or less is more preferable.

In the first step, the total application amount per unit area of the coloring material contained in the first ink in the area where the first ink and the second ink are applied in an overlapping manner is 0.1 to 2.5 mg / inch ² 0.2 mg / inch ² or more is more preferable, 0.5 mg / inch ² or more is more preferable, 1 mg / inch ² or more is particularly preferable, and 2 mg / inch ² or less is more preferable. It is preferable at the point which the image quality etc. of a recorded matter are further excellent as each application amount is the above, and it is easy to set it as the value of the below-mentioned ratio E-ratio H.
The application amount of each color material in the first step and the second step, the total application amount of color material, the application amount of flocculant in the reaction liquid application step, and the ratio E to ratio H described later are the first ink and the second ink. It is preferable in the area where the total application amount of the coloring material is the largest in the area where the ink is applied in an overlapping manner, because the image quality of the recorded matter can be further improved.

  In the first step and the second step, the first ink or the second ink can be ejected from the nozzle of the line head or the serial head by the ink jet method, and can be deposited on the recording medium. In the line method using a line head, the head is fixed and the recording medium is moved along the sub-scanning direction (longitudinal direction of the recording medium, transport direction), and interlocked with this movement, the nozzle opening of the head is By discharging the ink droplets, an image can be recorded on the recording medium. In the serial method using a serial head, the head is moved along the main scanning direction (horizontal direction and width direction of the recording medium), and ink droplets are ejected from the nozzle opening of the head in conjunction with this movement. Thus, the image can be recorded on the recording medium.

  The volatilizing amount of the volatile component contained in the reaction liquid and the first ink applied to the non-absorbing recording medium or the low-absorbing recording medium at the time of applying the second ink in the second step is the amount before the application. 95 mass% or less is preferable with respect to 100 mass% of total mass of the volatile component contained in a reaction liquid and a 1st ink, 85 mass% or less is more preferable, 80 mass% or less is more preferable. The content is more preferably 60% by mass or less, particularly preferably 50% by mass or less, and still more preferably 30% by mass or less from the viewpoint of excellent clogging reliability and excellent recording speed. On the other hand, 5% by mass or more is preferable, 10% by mass or more is more preferable, 50% by mass or more is particularly preferable, and 60% by mass or more is more preferable, in terms of further excellent bleeding suppression. Here, the “reaction liquid before application” means the reaction liquid before application of the reaction liquid of the reaction liquid to be applied to the recording medium in the reaction liquid application step, “first ink before application”. The term “1” means the first ink of the first ink to be applied to the recording medium in the first step before the application of the first ink. When the volatilization amount of the volatile component is 95% by mass or less, the reaction liquid and the second ink can be efficiently reacted, so that the recording speed can be increased. In addition, the volatilization amount of a volatile component can be calculated | required by the method as described in an Example.

  The number of moles of aggregating agent contained in the reaction liquid per unit area in the non-absorbing recording medium or the low-absorbing recording medium, in the area where the first ink and the second ink are applied in an overlapping manner (unit: mol) The ratio E of the total mass (unit: g) of the coloring material contained in the first ink and the second ink is preferably 800: 1 to 31,000: 1, more preferably 800: 1 to 16000: 1, and 1600 More preferably, 1 to 5100: 1. By setting the ratio E to 800: 1 or more, it is possible to prevent the deposition of the reaction solution, the occurrence of white turbidity, stickiness and odor due to the reaction solution. By setting the ratio E to 31000: 1 or less, it is possible to suppress bleeding during ink superposition. The ratio E can be controlled by the application amounts of the first ink, the second ink, and the reaction liquid.

  The number of moles of polyvalent metal salt contained in the reaction liquid (unit: mol) per unit area of the above-mentioned area of the non-absorbing recording medium or the low-absorbing recording medium, and the first ink and the second ink 1000: 1-31000: 1 are preferable, 1000: 1-15000: 1 are more preferable, and, as for ratio F with the total mass (unit: g) of the color material to be carried out, 1000: 1-5100: 1 are more preferable. By setting the ratio F to 1000: 1 or more, it is possible to prevent the precipitation of the polyvalent metal salt, the occurrence of cloudiness, stickiness and odor due to the polyvalent metal salt. By setting the ratio F to 31000: 1 or less, it is possible to suppress bleeding at the time of ink superposition. The ratio F can be controlled by the application amounts of the first ink, the second ink, and the reaction liquid.

  The number of moles (unit: mol) of the organic acid contained in the reaction liquid per unit area of the above-mentioned area of the non-absorbing recording medium or the low-absorbing recording medium and the colors contained in the first ink and the second ink The ratio G to the total mass (unit: g) of the material is preferably 800: 1 to 5500: 1, more preferably 800: 1 to 1700: 1, and still more preferably 1000: 1 to 1700: 1. By setting the ratio G to 800: 1 or more, it is possible to prevent the deposition of the organic acid, the white turbidity due to the organic acid, the stickiness, and the generation of the odor. By setting the ratio G to 5500: 1 or less, it is possible to suppress bleeding at the time of ink superposition. The ratio G can be controlled by the application amounts of the first ink, the second ink, and the reaction liquid.

  At least one mass selected from the group consisting of a receptor layer component and a cationic resin contained in a reaction liquid per unit area of the above-mentioned area of a non-absorbing recording medium or a low-absorbing recording medium (unit: The ratio H of G: to the mass (unit: g) of the coloring material contained in the first ink is preferably 7: 1 to 70: 1, and more preferably 7: 1 to 50: 1. When the ratio H is 7: 1 or more (the former), it tends to be more excellent in bleed suppression. When the ratio H is 70: 1 or less (the former), the application efficiency of the reaction liquid tends to be more excellent. The ratio H can be controlled by the application amount of the first ink and the reaction liquid.

  As is apparent from Tables 3 to 5, in the above-mentioned respective ratios, the ratio E is a ratio (colorant: coagulant), the ratio F is a ratio (colorant: polyvalent metal salt), and the ratio G is a ratio (colorant: Organic acid) and ratio H are ratios (coloring materials: at least one selected from the above group).

  In the recording method according to the present embodiment, the surface temperature of the recording medium in the first step and / or the second step is preferably 10 ° C. or more and 65 ° C. or less. Moreover, 50 degrees C or less is more preferable at the point which is more excellent in clogging reliability, and 40 degrees C or less is further more preferable. On the other hand, 20 ° C. or more is more preferable, 40 ° C. or more is more preferable, and 50 ° C. or more is particularly preferable in that the recording speed is further excellent. When the surface temperature of the recording medium is in the above range, the clogging reliability and the recording speed tend to be particularly excellent.

  Hereinafter, the present invention will be more specifically described using examples and comparative examples. The present invention is not limited at all by the following examples.

[Materials for Reaction Solution and Ink]
The main materials for the reaction liquid and ink used in the following Examples and Comparative Examples are as follows.
[Pigment]
Titanium dioxide: metal oxide NanoTek (R) Slurry CIAE Cyan pigment: C.I. I. Pigment blue 15: 3
[Polyvalent metal salt]
Magnesium sulfate heptahydrate (molecular weight 246.47 g / mol)
Calcium acetate monohydrate (molecular weight 176.18 g / mol)
Calcium nitrate tetrahydrate (molecular weight 164.09 g / mol)
[Organic acid]
Succinic acid (molecular weight 118.09 g / mol)
[Surfactant]
BYK 348 (Silicone-based surfactant, manufactured by Big Chemie Japan)
[Resin emulsion]
Joncryl 62J (acrylic styrene resin, manufactured by BASF)
[Receptive layer component]
Anionic colloidal silica ("Snowtex ZL" manufactured by Nissan Chemical Industries, Ltd.)
[Cationic resin]
Cationic resin emulsion ("Arrow base CD-1200" manufactured by UNITICA)
〔Organic solvent〕
1,2 hexanediol [moisturizer]
Propylene glycol

[Preparation of Reaction Solution and Ink]
The respective materials were mixed according to the composition (% by mass) shown in Table 1 below, and thoroughly stirred to obtain a reaction liquid, a first ink, and a second ink.

[Method of measuring surface tension]
The surface tension of the reaction solution was measured by the Wilhelmy method at a liquid temperature of 25 ° C. using a surface tension meter (surface tension meter CBVP-Z, etc., manufactured by Kyowa Interface Science Co., Ltd.).

[Preparation of ink set]
The obtained reaction liquid, the first ink, and the second ink were combined as shown in Table 2 to obtain an ink set.

[Examples 1 to 18, Comparative Examples 1 to 5]
A modified machine of PX-G 930 (manufactured by Epson Corporation) was used. The modification point is that a heater is attached to the platen to heat the recording medium. The nozzle pitch is 180 dpi. The ink set prepared above is discharged from the head in the order of the reaction liquid, the first ink and the second ink by the ink jet method under the recording conditions shown in Tables 1 to 3, and Toray PET, which is a non-absorbing recording medium A solid pattern was deposited on a film "Lumirror S10" (trade name, thickness 100 μm) or NP coated paper (manufactured by Lintec) which is a low-absorbent recording medium. At this time, a pattern 1 to which only the reaction liquid was applied, a pattern 2 to which only the reaction liquid and the first ink were overlapped, and a pattern 3 to which the reaction liquid, the first ink, and the second ink were overlapped were formed. The patterns 2 and 3 were simultaneously formed in contact with each other.

  Specifically, if pattern 3 is to be formed, the temperature of the recording medium is adjusted beforehand by the heater so that the temperature of the recording medium is as shown in Tables 3 to 5, and then the reaction liquid is applied to form a pattern (sub Next, the first ink is applied on the subpattern of the reaction liquid to form the subpattern of the first ink, and then the second ink is formed on the subpattern of the first ink. A subpattern was formed to form pattern 3. The temperature of the recording medium was adjusted by the platen heater so that the temperature in Tables 3 to 5 was maintained during the application of the reaction liquid, the first ink, and the second ink. Further, after the first step and before the start of the second step (at the start), the contents of the reaction components on the recording medium and the volatile components of the first ink are adjusted to the values in Tables 3 to 5 and the second The process was done. The recording resolution was set to 720 × 720 dpi, and the amount of reaction liquid per dot and the amount of ink were adjusted to be the amount of application shown in the table.

[Volatilization amount of volatile component of reaction liquid and first ink before second step]
The volatilization amount of the reaction liquid and the volatile component of the first ink in the pattern 3 after the first step and before the second step (when the recording medium is conveyed to the position facing the second ink head) is the following equation Calculated by. Here, Af is the total application amount (mg) of the reaction liquid and the first ink in the portion to be applied redundantly to the recording medium. Further, Ae is the total amount of the residual of the reaction liquid and the first ink on the recording medium in a state in which the reaction liquid and the first ink are dried (volatilized) to a state sufficient for using the recording material. Furthermore, A is the total mass of the reaction liquid and the first ink on the recording medium immediately before the second step.
Volatilization amount% of volatile component = ((Af-A) / (Af-Ae)) × 100

  Af can be determined from the ejection data of the printer and the mass per dot as the application amounts of the reaction liquid and the first ink in pattern 3. A can be determined by measuring the difference between the mass of the recording medium at the start of the application of the second ink and the mass of the recording medium before the reaction liquid application step. When measuring the volatilization amount of the volatile component, it is convenient to use a recording medium prepared for the measurement. The measurement was measured by an electronic balance. At the time of measurement, the reaction liquid and the first ink are applied, and then the relationship between the drying time and the amount of volatilization when predetermined heating drying is performed with a platen is determined and placed. When recording with the recording apparatus, the time from the application of the reaction liquid and the first ink to the application of the second ink is taken as any of the relationship between the drying time and the volatilization amount determined above. It is possible to achieve the desired volatilization amount.

[Evaluation]
[Bleeding in overlapping recording of the first ink and the second ink]
The amount of the second ink applied in pattern 3 was changed between 30 and 200%, with the values described in Tables 3 to 5 as 100%, to obtain recorded articles. The bleeding at the time of superposition recording of the first ink and the second ink was visually observed at the contact portion between the pattern 3 and the pattern 2 of the obtained recorded matter, and evaluation was made according to the following evaluation criteria. Note that “200%” is a value that assumes the maximum application amount of the total of a plurality of inks in the case of recording a secondary color or more using a plurality of color inks. It can be said that a recorded matter in which bleeding is suppressed can be obtained even when a plurality of color inks are used if A or AA in the following evaluation criteria.
(Evaluation criteria)
AA: Even if the second ink application amount is 200%, there is no color mixing.
A: There is no color mixing if the application amount of the second ink is up to 100%.
B: There is no color mixing if the application amount of the second ink is up to 50%.
C: Color mixing occurs even when the application amount of the second ink is 30%.

[Deposition of reaction liquid on recording medium]
The deposition of the reaction liquid on the recording medium was observed by visually observing the pattern 1 and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: No precipitation is observed.
B: Precipitation is observed but no white turbidity is observed.
C: Precipitation is observed, and cloudiness is observed.

[White turbidity of image area]
The white turbidity of the portion (image portion) to which the ink was applied was observed visually with the pattern 3 and was evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: There is no cloudiness.
B: White turbidity is observed.

[Fat unevenness of the first ink on the recording medium]
The solid unevenness of the first ink on the recording medium was observed by visually observing the pattern 2 and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: No aggregation unevenness is found in the first ink.
B: Some aggregation unevenness is observed in the first ink.
C: Cohesive unevenness is considerably observed in the first ink.

[Odor of recording material]
The odor of the recorded matter was evaluated based on the following evaluation criteria by sensory evaluation of pattern 3.
(Evaluation criteria)
A: There is no odor.
B: There is a slight odor.
C: The odor is very high.

Stickiness of recorded material
The tackiness of the recorded matter was evaluated according to the following evaluation criteria by superimposing pattern 3 on the printing surfaces.
(Evaluation criteria)
A: There is no sticking even if it is left for 1 day in the state where two printing sides are overlapped. (No stickiness)
B: The two printed surfaces are stacked on each other for one day, and when one is lifted, the two sheets stick, but they fall off within one minute. (Slightly sticky,)
C: The two printed surfaces are stacked one on another for one day, and when one is lifted, the two sheets stick together, but they do not come off even if it takes more than one minute. (There is stickiness.)

[Recording speed]
The recording speed was evaluated based on the recording speed at which the pattern 3 was obtained according to the following evaluation criteria.
(Evaluation criteria)
A: A single A4 size recording medium can be recorded in less than 30 seconds.
B: Recording can be performed in 30 seconds to 1 minute on one A4 size recording medium.
C: Recording can be performed if it exceeds 3 minutes on one A4 size recording medium.

[Clogging reliability]
The clogging reliability was evaluated by visually observing the nozzles after the pattern 3 was recorded on 50 sheets of the A4 size recording medium, and evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: Even if 50 sheets are recorded on the recording medium, there will be neither nozzle missing nor nozzle bending.
B: When 50 sheets are recorded on the recording medium, nozzle missing does not occur but nozzle bending occurs.
C: When 50 sheets are recorded on the recording medium, nozzle missing and nozzle bending occur.

  From the comparison between Examples and Comparative Examples 1 to 3, it was found that the ink set in which the reaction liquid does not contain a coagulant is inferior in the effect of suppressing the bleeding of the second ink. In addition, although the effect of suppressing the bleeding of the second ink is improved by heating the recording medium to 70 ° C. when the reaction liquid does not contain the coagulant according to the comparison between the example and the comparative example 4, It turned out that clogging reliability is inferior.

  From Examples 1 to 4, it was found that bleeding was suppressed as the amount of polyvalent metal salt used increased. It was also found that the less the amount of polyvalent metal salt used, the more the precipitation of the reaction liquid on the recording medium and the white turbidity of the recorded matter are suppressed. Further, from Examples 5 to 11, it was shown that there is a similar tendency even when other polyvalent metal salts and organic acids are used.

  Furthermore, it was found from the Examples 12 and 13 that bleeding is further suppressed by using a component serving as a receptive layer and a cationic resin. Moreover, it turned out that the one where heat assist temperature is low is excellent in clogging reliability by comparison with Example 14 and another Example, and Comparative Examples 2 and 4. Further, it was found from Examples 2 and 14 to 16 that bleeding tends to be suppressed when the volatilization amount of the volatile component is high, but bleeding is suppressed when the volatilization amount is not too high. It is presumed that this is because if the volatilization amount is too high, the coagulant contained in the reaction liquid can not be sufficiently mixed onto the first ink, and the reaction between the second ink and the coagulant becomes difficult . In addition, it was found that the lower the volatilization amount, the recording speed and the clogging reliability could be both further improved.

  From Example 17, it was shown that the effects of the present invention can be obtained by reversing the color and white of the first ink and the second ink. Also, from Examples 9 and 18, it was shown that the effects of the present invention can be obtained even with other recording media. When a low-absorbent recording medium is used, there is a tendency to be further excellent in bleeding, but on the other hand, the non-absorbent recording medium is more excellent in water resistance and abrasion resistance, When used in a recording medium, the present invention has been found to be more useful. Furthermore, as the content of the surfactant in the reaction liquid is large and the surface tension is lower according to the comparison between Example 19 and the other examples, bleeding, precipitation of the reaction liquid on the recording medium, or recording material becomes lower as the surface tension decreases. It turned out that cloudiness is suppressed.

  Although recording is performed using a serial printer in the above example, recording can also be performed using a line printer as shown in FIG. In this case, after the reaction liquid and the first ink are applied by the reaction liquid applying head and the first ink applying head, the time taken for the second ink to be applied after being conveyed to a position facing the second ink head By adjusting the recording medium conveyance speed or the like, it is possible to control the volatilization amount of the recording medium.

Claims (15)

A reaction liquid containing a coagulant, a first ink containing a coloring material, and a second ink containing a coloring material,
Used for recording on non-absorbing recording media or low-absorbing recording media,
The reaction liquid, the first ink, and the second ink are applied to the recording medium in an overlapping manner in this order, and used.
Ink set. At least one of the first ink and the second ink is a color ink containing a color colorant or a black ink containing a black colorant.
The ink set according to claim 1. The other of the first ink and the second ink is a white ink containing a white coloring material or a metallic ink containing a metallic coloring material.
The ink set according to claim 2. The coagulant includes at least one selected from the group consisting of polyvalent metal salts and organic acids.
The ink set according to any one of claims 1 to 3. The ratio (color material) of the number of moles of the polyvalent metal salt (unit: mol) contained in the reaction liquid to the total mass (unit: g) of the color material contained in the first ink and the second ink : A polyvalent metal salt) is from 1000: 1 to 31000: 1,
The ink set according to claim 4. Ratio (color material: organic acid) of the number of moles of the organic acid (unit: mol) contained in the reaction liquid and the total mass (unit: g) contained in the color material of the first ink and the second ink ) Is 800: 1 to 5500: 1,
The ink set according to claim 4 or 5. The first ink is a white ink containing a white coloring material or a metallic ink containing a metallic coloring material,
The second ink is a color ink containing a color material or a black ink containing a black material.
The ink set according to any one of claims 1 to 6. The surface tension of the reaction solution is 55 mN / N or less at 25 ° C.
The ink set according to any one of claims 1 to 7. The reaction liquid further contains at least one selected from the group consisting of a component to be a receiving layer of the ink applied next to the reaction liquid, and a cationic resin.
The ink set according to any one of claims 1 to 8. At least one type (unit: g) selected from the group consisting of the component to be the receiving layer, which is contained in the reaction liquid, and the cationic resin, and the coloring material (unit: g) contained in the first ink The mass ratio thereof (coloring material: at least one selected from the group) is 7: 1 to 70: 1,
The ink set according to claim 9. A recording method using the ink set according to any one of claims 1 to 10, wherein
A reaction liquid applying step of applying a reaction liquid contained in the ink set to a non-absorbing recording medium or a low-absorbing recording medium;
A first step of applying a first ink contained in the ink set to the area to which the reaction liquid has been applied;
A second step of applying a second ink contained in the ink set to the area to which the first ink has been applied;
Recording method. After the first step, before the second step, volatilization of volatile components contained in the reaction liquid and the first ink on the non-absorbing recording medium or the low-absorbing recording medium The amount is 95% by mass or less based on 100% by mass of the total mass of volatile components contained in the reaction liquid and the first ink before application.
A recording method according to claim 11. The number of moles (unit: mol) of polyvalent metal salt contained in the reaction solution per unit area of the non-absorbing recording medium or the low-absorbing recording medium, the first ink, and the second ink The ratio (color material: polyvalent metal salt) to the total mass (unit: g) of the color material contained in is from 1000: 1 to 31000: 1,
A recording method according to claim 11 or 12. The number of moles (unit: mol) of the organic acid contained in the reaction liquid per unit area of the non-absorbing recording medium or the low-absorbing recording medium, and included in the first ink and the second ink The ratio (color material: organic acid) to the total mass (unit: g) of the color material to be extracted is 800: 1 to 5500: 1,
The recording method according to any one of claims 11 to 13. From the component to be the receptive layer of the first ink and the second ink contained in the reaction liquid per unit area of the non-absorbing recording medium or the low-absorbing recording medium, and a cationic resin A ratio (coloring material: at least one kind selected from a group) of at least one kind of mass (unit: g) selected from the group consisting of: and a mass (unit: g) of a coloring material contained in the first ink 7: 1 to 70: 1,
The recording method according to any one of claims 11 to 14.

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