JP7676843B2 - Ink-jet ink composition and recording method. - Google Patents

Description

The present invention relates to an inkjet ink composition, an ink set, and a recording method.

2. Description of the Related Art Conventionally, methods of manufacturing decorative articles with a glossy appearance have included metal plating, foil stamping using metal foil, and thermal transfer using metal foil.
However, these methods are inconvenient in terms of being able to print freely on desired areas.

On the other hand, compositions containing pigments or dyes are used as inkjet inks that are applied to recording media by inkjet printing, or as paints. These methods have the advantage that they allow printing freely on the desired areas.

However, when simply applying metal particles instead of pigments or dyes, it is often difficult to fully utilize the inherent properties of metal, such as its luster.

In order to solve the above problems, it has been proposed to use metal particles whose surfaces are treated with a fluorine-based compound (see, for example, Patent Document 1).

JP 2015-189775 A

However, the ink composition still did not have sufficient ejection stability when ejected from an inkjet head.

The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

An inkjet ink according to an application example of the present invention is an inkjet ink composition comprising a metal pigment and a liquid medium component, the metal pigment being composed of metal particles, the metal particles being surface-modified with a surface treatment agent, the surface treatment agent being at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), and the inkjet ink composition is a water-based ink or a solvent-based ink.
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is 1 or 2.)

An ink set according to an application example of the present invention is an ink set including the above-mentioned ink-jet ink composition and an ink-jet ink composition that is a colored ink containing a coloring material.
A recording method according to an application example of the present invention is a recording method comprising a step of ejecting the above-mentioned ink-jet ink composition from an ink-jet head and depositing it onto a recording medium.

FIG. 1 is a schematic diagram of an example of a recording device.

Preferred embodiments of the present invention will now be described in detail.
[1] Metal Pigment Composition First, the metal pigment composition of the present invention will be described.

Conventionally, methods of manufacturing decorative articles with a glossy appearance have included metal plating, foil stamping using metal foil, and thermal transfer using metal foil.
However, these methods have characteristics such as difficulty in applying them to curved surfaces.

On the other hand, compositions containing coloring materials are used as inkjet inks that are applied to recording media by inkjet printing, or as paints. These methods are advantageous in that they can be suitably applied to curved surfaces and that the ink can be freely applied to the desired area.

However, when metal pigments are simply used as coloring materials, the ejection stability when ejected from an inkjet head is insufficient. In addition, there is a tendency for the inherent properties of metal, such as gloss, to not be fully exhibited.

Conventionally, it has been proposed to use metal particles that have been surface-treated with a fluorine-based compound. This improves the gloss of the portion to which the composition is attached to a certain extent, but does not provide sufficient ejection stability when ejected from an inkjet head. Furthermore, it is not sufficient in terms of providing a composition that is excellent in gloss and dispersion stability.

The inventors have conducted intensive research aimed at solving the above-mentioned problems, and as a result have arrived at the present invention. That is, the ink-jet ink composition of the present invention comprises a metal pigment and a liquid medium component, the metal pigment is made of metal particles, the metal particles are surface-modified with a surface treatment agent, the surface treatment agent is at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), and the ink-jet ink composition is a water-based ink or a solvent-based ink.
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is 1 or 2.)

This allows the ink to be suitably applied to the production of colored bodies that have excellent inkjet ejection stability, excellent dispersion stability of metal particles, and excellent gloss. In particular, the above-mentioned excellent effects can be obtained whether the ink is applied to a solvent-based ink or a water-based ink. In addition, since there is no need to use the above-mentioned fluorine-based surface treatment agent, it is also advantageous from the perspective of environmental friendliness.

In addition, since the inkjet ink composition is applied to ejection by the inkjet method, it is possible to enjoy the benefits of applying the inkjet method, such as the ability to more suitably form fine patterns and excellent on-demand performance. In addition, the inkjet composition can have excellent ejection stability, etc. of droplets in a relatively short period of time after production, and can also have excellent ejection stability, etc. of droplets even when stored for a long period of time or under harsh conditions.

On the other hand, if the above conditions are not met, satisfactory results will not be obtained.
For example, if the ink composition does not contain a metal pigment whose surface has been modified with the above-mentioned surface treatment agent, the following problems will occur: the ejection stability will be poor, the dispersion stability of the metal particles will be reduced, and the gloss of a colored product produced using the ink composition will be significantly reduced.

In the following description, the surface treatment agent, which is at least one selected from the group consisting of the compound represented by formula (1) and the compound represented by formula (2), is also referred to as the "specific surface treatment agent."

The components of the ink composition of the present invention will be described below. Note that an ink composition that is discharged from an inkjet head by an inkjet method and deposited on a recording medium for use in recording is called an inkjet ink composition or inkjet ink. An inkjet ink composition may also be simply called an ink composition or ink.

The ink composition of the present invention is an ink containing a metal pigment, and is an ink capable of recording an image having a metallic luster due to the metal pigment on a recording medium. It is also called metallic ink or metallic luster ink. When it is said that an excellent luster can be obtained by using the ink composition of the present invention, the luster may refer to a metallic luster.

[1-1] Metal Pigment The metal pigment composition of the present invention contains a metal pigment made of metal particles.
The metal particles constituting the metal pigment are surface-modified with a specific surface treatment agent, which will be described in detail later. More specifically, it is believed that the OH groups on the surfaces of the metal particles react with the phosphorus-containing acid groups of the specific surface treatment agent, thereby bonding the metal particles to the specific surface treatment agent through covalent bonds or hydrogen bonds.

Metal particles are particles in which at least a portion of the visible part is made of a metal material, and typically the area near the outer surface is made of a metal material.

Metal particles are a component that has a significant impact on the appearance of colored bodies produced using metal pigment compositions.

The metal particles may be made of a metal material at least in the region including the surface area. For example, the entire metal particle may be made of a metal material, or the metal particle may have a base made of a nonmetallic material and a coating made of a metal material that covers the base. The metal particles may also have an oxide coating, such as a passive film, formed on the surface. Even with such metal particles, the problems described above have occurred in the past, and the application of the present invention provides the excellent effects described above.

As the metal material constituting the metal particles, a single metal or various alloys can be used. Examples include aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, iron, copper, etc. Among these, the metal particles are preferably made of aluminum or an aluminum alloy. The reason why aluminum and aluminum alloys are preferred is that they have a lower specific gravity than iron, etc. As a result, when particles made of aluminum or an aluminum alloy are dispersed in a metal pigment composition, sedimentation proceeds very slowly, and the metal pigment composition can be stored for a longer period of time while effectively preventing the occurrence of uneven concentration, etc.

In addition, the colored body produced using the metal pigment composition can have a particularly excellent gloss and luxurious feel while suppressing an increase in the production cost of the colored body. Aluminum and aluminum alloys inherently exhibit particularly excellent gloss among various metal materials, but the present inventors have found that when particles composed of these materials are applied to a metal pigment composition, the following problems arise. That is, the present inventors have found that the storage stability of the metal pigment composition is particularly low, and that, particularly when such a metal pigment composition is used as an inkjet composition, problems such as a decrease in ejection stability due to an increase in viscosity caused by gelation are particularly likely to occur. In contrast, when the metal pigment is surface-modified with a specific surface treatment agent, the occurrence of the above problems can be reliably prevented even when particles composed of aluminum or an aluminum alloy are used. That is, when the metal particles are composed of aluminum or an aluminum alloy, the effect of the present invention is more pronounced.

The metal particles may be of any shape, such as spherical, spindle-shaped, or needle-shaped, but are preferably scale-shaped.

This allows the main surfaces of the metal particles to be arranged on the treated body to which the metal pigment composition is applied so as to conform to the surface shape of the treated body. As a result, the glossiness and other properties inherent to the metal material constituting the metal particles can be more effectively exhibited in the resulting colored body, and the colored body can be made to have particularly excellent glossiness and luxurious feel, as well as particularly excellent abrasion resistance. In addition, in an ink composition in which the metal pigment is not surface-modified with a specific surface treatment agent, if the metal particles are scaly, the storage stability of the metal pigment composition tends to be particularly low, and when the metal pigment composition is used as an inkjet composition, the ejection stability of the inkjet composition tends to be particularly low. In addition, it is not possible to express the excellent glossiness and other properties of the scaly metal particles.

In contrast, when the metal pigment composition is a metal pigment in which the metal pigment has been surface-modified with a specific surface treatment agent, the occurrence of the above problems can be reliably prevented even if the metal particles are scaly. In other words, when the metal particles are scaly, the effect of the present invention is more pronounced.

In the present invention, the term "scale-like" refers to a shape such as a flat plate or curved plate, in which the area when viewed in plan is larger than the area when viewed in an angle perpendicular to the observation direction when observed from a predetermined angle. In particular, when observed in a direction in which the projected area is maximum, that is, the ratio S1/S0 of the area _S1 [ ^μm2 ] when viewed in plan to the area _S0 [ ^μm2 ] when observed in a direction perpendicular to the observation direction in which the area is _maximum , is preferably ₂ or more, more preferably 5 or more, and even more preferably 8 or more. It is further preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more.
The upper limit of _S1 / _S0 is not particularly limited, but is preferably 1000, more preferably 500, and even more preferably 100. Furthermore, it is preferably 80 or less.
As this value, for example, 50 random particles are observed, and the average value of the values calculated for these particles can be used. The observation can be performed using, for example, an electron microscope, an atomic force microscope, or the like.

Alternatively, the volume average particle diameter (D50) and average thickness described below may be used, the units may be adjusted to match, and the volume average particle diameter (D50)/average thickness may be used to define the above range.

When the metal particles are scaly, the lower limit of the average thickness of the metal particles is not particularly limited, but is preferably 5 nm, more preferably 10 nm, and even more preferably 15 nm. When the metal particles are scaly, the upper limit of the average thickness of the metal particles is not particularly limited, but is preferably 90 nm, more preferably 70 nm, even more preferably 50 nm, and most preferably 30 nm. Furthermore, 20 nm or less is preferable.

The average thickness can be measured using an atomic force microscope. For example, but not limited to, it can be measured by atomic force microscopy using NanoNavi E-Sweep (manufactured by SII Nanotechnology). For example, measurements are taken of 50 random metal particles and the average value is calculated.

This allows the effect of the scale-like particles described above to be more pronounced.

The lower limit of the volume average particle diameter of the metal particles is not particularly limited, but is preferably 0.20 μm, more preferably 0.25 μm, and even more preferably 0.30 μm. The upper limit of the volume average particle diameter of the metal particles is not particularly limited, but is preferably 1.00 μm, more preferably 0.90 μm, and even more preferably 0.80 μm.

This improves the storage stability and water resistance of the ink composition, while more effectively preventing the occurrence of undesired color unevenness in colored products produced using the ink composition, and improves the gloss and abrasion resistance of the colored products.

In the present invention, the volume average particle diameter refers to the median diameter of the volume distribution measured by using a laser diffraction/scattering method for a particle dispersion, and is the particle size that is exactly 50% of the median value when the results of multiple measurements are expressed as the cumulative abundance ratio of each size. When the metal particles are scaly, the volume average particle diameter is calculated based on the shape and size of the metal particles when converted to spheres.

The upper limit of the particle diameter D90 at a volume cumulative distribution rate of 90% from the fine particle side of the metal particles contained in the ink composition is preferably 1.50 μm, more preferably 1.20 μm, and even more preferably 0.95 μm.

This improves the storage stability and water resistance of the ink composition, while more effectively preventing the occurrence of undesired color unevenness in colored products produced using the ink composition, and improves the gloss and abrasion resistance of the colored products.

The lower limit of the content of metal particles in the ink composition is not particularly limited, but is preferably 0.1% by mass, more preferably 0.2% by mass, and even more preferably 0.3% by mass. Furthermore, 0.5% by mass or more is preferable. The upper limit of the content of metal particles in the ink composition is not particularly limited, but is preferably 30% by mass, more preferably 20% by mass, even more preferably 15% by mass, and particularly preferably 10% by mass. Furthermore, 5% by mass or less is preferable. Further, 2.4% by mass or less is preferable, more preferably 2.2% by mass or less, and even more preferably 1.8% by mass or less.

This allows the ink composition to have better storage stability, water resistance, etc., while also providing the colored parts formed using the ink composition with particularly excellent gloss and abrasion resistance.

The metal particles may be produced by any method, but when they are made of Al, they are preferably obtained by forming a film made of Al by a vapor phase film formation method and then pulverizing the film. This allows the inherent luster and other properties of Al to be more effectively expressed in the colored portion formed using the metal pigment composition of the present invention. In addition, the variation in properties between particles can be suppressed. Furthermore, by using this method, even relatively thin metal particles can be suitably produced.

When manufacturing metal particles using such a method, for example, a film made of Al is formed on a substrate, whereby the metal particles can be suitably manufactured. The substrate can be, for example, a plastic film such as polyethylene terephthalate. The substrate may also have a release agent layer on the film forming surface.

The crushing is preferably performed by applying ultrasonic vibrations to the film in a liquid. This makes it possible to easily and reliably obtain metal particles having a particle size as described below, and also suppresses variations in size, shape, and properties between the individual metal particles.

When grinding is performed using the above-mentioned method, the liquid can be preferably an alcohol, a hydrocarbon compound, an ether compound, or a polar compound such as propylene carbonate, γ-butyrolactone, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, cyclohexanone, or acetonitrile. By using such a liquid, it is possible to prevent unintended oxidation of the metal particles, while improving the productivity of the metal particles and reducing the variation in size, shape, and properties between the individual particles.

Examples of alcohols include methanol, ethanol, propanol, and butanol. Examples of hydrocarbon compounds include n-heptane, n-octane, decane, dodecane, tetradecane, toluene, xylene, cymene, durene, indene, dipentene, tetrahydronaphthalene, decahydronaphthalene, and cyclohexylbenzene. Examples of ether compounds include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, tetraethylene glycol monobutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol n-butyl ether, tripropylene glycol dimethyl ether, triethylene glycol diethyl ether, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, p-dioxane, and tetrahydrofuran.

[1-2] Specific Surface Treatment Agent The above-mentioned metal particles are surface-modified with a specific surface treatment agent.

The specific surface treatment agent is at least one selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2).
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is 1 or 2.)

One or more of the specific surface treatment agents may be selected. When two or more are selected, one or more of the compounds represented by formula (1) and one or more of the compounds represented by formula (2) may be selected, two or more of the compounds represented by formula (1) may be selected, and two or more of the compounds represented by formula (2) may be selected. In these cases, the above R and a may be independent for each selected compound. Also, when a is 2, R in the compound may be independent for each R.

In the above formula, R is a hydrocarbon group having a carbon skeleton with 13 or more carbon atoms, that is, a hydrocarbon group having a skeleton in which 13 or more carbon atoms are bonded in succession.
In formula (1), any carbon atom in the carbon skeleton of R having 13 or more carbon atoms is directly bonded to the oxygen atom of O in (R-O), and the oxygen atom is directly bonded to the phosphorus atom of P.
In formula (2), any one of the carbon atoms of the carbon skeleton of R having 13 or more carbon atoms is directly bonded to the phosphorus atom of P.
For this reason, it is presumed that when the treatment agent reacts with the metal pigment at the hydroxyl group bonded to the phosphorus atom of the treatment agent to surface-modify the metal pigment, R can be located relatively close to the metal pigment, thereby providing excellent dispersion stability of the metal pigment.
It is also presumed that the fact that R is a relatively long-chain hydrocarbon group can impart excellent dispersion stability to the metal pigment.

If the dispersion stability of the metal pigment is poor, agglomerates of the metal pigment are generated, which causes poor ejection stability. In addition, the gloss may be poor if the agglomerates of the metal pigment cannot be neatly aligned on the recording medium, or if a sufficient amount of ink cannot be ejected and deposited. However, the ink of this embodiment has excellent dispersion stability, ejection stability, gloss, etc.

Examples of hydrocarbon groups having a carbon skeleton with 13 or more carbon atoms include saturated hydrocarbon groups that do not have double bonds or triple bonds between carbon atoms, and unsaturated hydrocarbon groups that have double bonds or triple bonds between carbon atoms. The hydrocarbon group of R may be an aromatic hydrocarbon group whose carbon skeleton has an aromatic ring structure, or a chain or cyclic aliphatic hydrocarbon group. Chain aliphatic hydrocarbon groups are particularly preferred because of their excellent dispersion stability. Chain aliphatic hydrocarbon groups may be branched or straight, with straight-chain types being preferred because of their excellent dispersion stability, ejection stability, and gloss. In this case, for example, a large number of specific surface treatment agents can be used to modify the surface of the metal pigment, and it is presumed that sufficient effects are achieved.

R is a hydrocarbon group, and therefore has a bond between a carbon atom and a hydrogen atom. When R does not have a substituent, R is a hydrocarbon group consisting of a carbon atom and a hydrogen atom. For example, when R is a chain-like aliphatic hydrocarbon group, examples include an alkyl group, an alkenyl group, and an alkynyl group. In this case, dispersion stability is superior and this is preferable, particularly when the ink is a solvent-based ink.

R is a hydrocarbon group having a carbon skeleton with 13 or more carbon atoms, containing carbon atoms and hydrogen atoms, and at least a bond between a carbon atom and a hydrogen atom. Therefore, some of the hydrogen atoms that the hydrocarbon group may have may be substituted with a substituent. Examples of the substituent include a carboxyl group, a hydroxyl group, an amino group, and an oxyalkylene-containing group. In this case, depending on the type of liquid medium component, affinity with the liquid medium component of the metal pigment is imparted, and dispersion stability is more excellent and preferable. This is particularly preferred when the ink composition of the present invention is an aqueous composition. In particular, when substituted with a carboxyl group, a hydroxyl group, an amino group, an oxyalkylene-containing group, etc., water affinity is imparted and this is preferable. When some of the hydrogen atoms that the hydrocarbon group of R may have are substituted with a substituent, the number of the substituents is preferably 50% or less of the number of hydrogen atoms of the hydrocarbon group when R does not have a substituent, and more preferably 10% or less. The number of the substituents is preferably 5 or less, and particularly preferably 3 or less. Further, 2 or less is preferable, and 1 or less is more preferable. The number of substituents is 0 or more, and when substituted with a substituent, the lower limit of the number of substituents is 1 or more. It is preferable that the substituent is provided on the carbon atom that is farthest from the phosphorus atom in the formula, as this provides better dispersion stability.

When the substituent is an oxyalkylene-containing group, the oxyalkylene-containing group is a group having an oxyalkylene structure. The oxyalkylene structure is also called an alkylene oxide structure. The oxyalkylene-containing group has one or more alkylene oxide units, and may have two or more. In particular, it may have a structure in which a plurality of alkylene oxide units are repeated. The number of repeating alkylene oxide units is preferably 10 or less, and more preferably 4 or less. The lower limit is 1 or more, preferably 2 or more, and more preferably 3 or more. The number of carbon atoms of the alkylene in the alkylene oxide unit is preferably 1 to 4.

R in the above formula (1) and formula (2) is a hydrocarbon group having a carbon skeleton with 13 or more carbon atoms, and preferably has a carbon skeleton with 14 to 30 carbon atoms. Furthermore, the carbon skeleton preferably has a carbon skeleton with 15 to 28 carbon atoms, more preferably 16 to 25 carbon atoms, and even more preferably 17 to 25 carbon atoms.

This allows the ink composition to have excellent ejection stability. It is presumed that this is related to the excellent dispersion stability of the metal particles in the ink. This also allows the glossiness of the recorded matter produced using the ink composition to be improved.

The compound represented by formula (1) is a compound in which one or two of the three hydroxyl groups of phosphoric acid are esterified with an R group. The compound represented by formula (2) is a compound in which the hydrogen atom bonded to the phosphorus atom of phosphonic acid is replaced with an R group.

The ink composition of the present invention may contain multiple types of compounds as the specific surface treatment agent. In such a case, the same metal particles may be surface-treated with multiple types of surface treatment agents. In addition, the ink composition of the present invention may contain metal particles that have been surface-treated with different specific surface treatment agents.

Surface treatment of metal particles with a specific surface treatment agent may be carried out, for example, by including a specific surface treatment agent in a liquid when a metal film formed by a vapor phase deposition method is pulverized in the liquid to form metal particles, as described above.

When surface treatment with multiple types of specific surface treatment agents is performed on the same metal particles, the surface treatment may be performed in multiple steps corresponding to each specific surface treatment agent, or the surface treatment with multiple types of specific surface treatment agents may be performed in the same step.

The lower limit of the content of the specific surface treatment agent in the ink composition is not particularly limited, but is preferably 0.01% by mass, more preferably 0.03% by mass, and even more preferably 0.05% by mass.
On the other hand, the upper limit of the content of the specific surface treatment agent in the metal pigment composition is not particularly limited, but is preferably 10% by mass, more preferably 7.0% by mass, even more preferably 5.0% by mass, and even more preferably 2.0% by mass or less.

This improves the dispersion stability of the metal particles in the ink composition, and the gloss and abrasion resistance of the colored body produced using the metal pigment composition.

In particular, the lower limit of the content of the specific surface treatment agent in the ink is not particularly limited, but is preferably 0.01% by mass, more preferably 0.03% by mass, and even more preferably 0.05% by mass, and is further preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more.
On the other hand, the upper limit of the content of the specific surface treatment agent in the ink is not particularly limited, but is preferably 1.5% by mass, more preferably 1.0% by mass, even more preferably 0.8% by mass, more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less.

The content of the specific surface treatment agent in the ink composition is not particularly limited, but is preferably 1.0 parts by mass or more and 50 parts by mass or less, more preferably 1.5 parts by mass or more and 40 parts by mass or less, and even more preferably 2.0 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of metal particles. Furthermore, 5 parts by mass or more and 20 parts by mass or less is preferable. Or 10 parts by mass or more and 28 parts by mass or less is preferable.

The above content and amount are the content and amount of the specific surface treatment agent contained in the ink composition, including the specific surface treatment agent that modifies the surface of the metal pigment.

This makes it possible to further improve the ejection stability of the ink composition, the dispersion stability of the metal particles, and the glossiness of the colored body produced using the metal pigment composition. It also makes it possible to further improve the ejection stability when stored for a long period of time or under harsh conditions.

[1-3] Liquid Medium Component The ink composition of the present invention contains a liquid medium component.
The liquid medium component is a component that is liquid by itself, and in the ink composition of the present invention, it mainly functions as a dispersion medium for dispersing metal particles. It also makes it easier for the composition to adhere to a target object. In other words, by including the liquid medium component in the ink, the viscosity of the ink can be made relatively low, making it easier to eject by inkjet, and also making it easy to adjust the surface tension of the ink, for example, by lowering it.

Furthermore, the ink composition contains a liquid medium component, which enables the ink to be ejected by inkjet printing.
Examples of the liquid medium component include water and various organic solvents.

When the ink is a water-based ink or a solvent-based ink containing a liquid medium component, the liquid medium component evaporates from the ink attached to the recording medium and the solids contained in the ink become a dried coating, thereby fixing the ink. During this process, a phenomenon called leafing occurs in which the metallic pigments contained in the ink float and line up neatly above the ink, resulting in an excellent metallic luster. Since the ink contains a liquid medium component and has a relatively low viscosity, leafing is likely to occur, and since the liquid medium component takes time to evaporate, it is easy to ensure that there is enough time for leafing to occur. Therefore, when the ink is a water-based ink or a solvent-based ink containing a liquid medium component, it is preferable because it is easy to obtain an excellent metallic luster.

On the other hand, when the ink is a water-based ink or a solvent-based ink containing a liquid medium component, the liquid medium component has a relatively low viscosity, so the metal pigment is likely to settle, and especially when the dispersion stability of the metal pigment is insufficient, the metal pigment is likely to settle and the ejection stability tends to be poor, so attention must be paid to the ejection stability and dispersion stability. In addition, depending on the liquid medium component, the dispersion stability of the metal pigment may be poor, so attention must be paid. Even in such a situation, the ink composition of the present embodiment is necessary because it can provide excellent dispersion stability and ejection stability.
From this viewpoint, it is preferable that the ink composition is not a photocurable ink that is cured by irradiation with light such as ultraviolet light.

The solvent-based ink and the water-based ink refer to inks containing 40% by mass or more of a liquid medium component.
The solvent-based ink refers to an ink containing less than 30% by mass of water among the liquid medium components contained in the ink, whereas the water-based ink refers to an ink containing 30% by mass or more of water among the liquid medium components contained in the ink.

Solvent-based inks have superior wetting and spreading properties compared to water-based inks, especially on low-absorption or non-absorption recording media. In addition, compared to water-based inks, the ink tends to dry more slowly. As a result, the metal pigments tend to leaf on the recording media, which is preferable since it tends to produce a higher gloss. On the other hand, water-based inks are preferable from the viewpoint of reducing environmental pollution, etc.

When the ink composition of the present invention is a solvent-based ink (solvent-based composition) containing an organic solvent as a liquid medium component, the dispersion stability of the metal particles in the ink composition, and the gloss and abrasion resistance of the colored body produced using the ink composition can be further improved. In addition, when the recording medium is a low-absorbency or non-absorbency recording medium, the adhesion and abrasion resistance of the ink are further improved, which is preferable.

In addition, when the ink composition of the present invention is an aqueous ink (aqueous composition) containing water as a liquid medium component, the ink composition can have a sufficiently excellent dispersion stability of metal particles, and the colored body produced using the ink composition can have a sufficiently excellent gloss and abrasion resistance, while the ink composition can have a smaller environmental impact.

As the organic solvent contained in the ink composition of the present invention, for example, alcohols, hydrocarbon compounds, ether compounds, ketones, esters, and polar compounds such as propylene carbonate, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, cyclohexanone, and acetonitrile can be suitably used.

Examples of alcohols include monohydric alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; and polyhydric alcohols such as ethylene glycol, propylene glycol, and 1,2-hexanediol. Examples of hydrocarbon compounds include n-heptane, n-octane, decane, dodecane, tetradecane, toluene, xylene, cymene, durene, indene, dipentene, tetrahydronaphthalene, decahydronaphthalene, and cyclohexylbenzene.

Examples of the ether compounds include glycol ethers, etc. Examples of the glycol ethers include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, tetraethylene glycol monobutyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol n-butyl ether, tripropylene glycol dimethyl ether, triethylene glycol diethyl ether, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, etc.
Examples of the glycol ethers include glycol diethers and glycol monoethers, with glycol diethers being preferred.
Ether compounds are also called ethers. Other examples of ethers include p-dioxane and tetrahydrofuran. Examples of ketones include acetone, methyl ethyl ketone, and diethyl ketone.

Examples of esters include ethyl acetate, propyl acetate, and butyl acetate. Examples of esters include cyclic esters. Examples of cyclic esters include lactones such as gamma-butyrolactone.

When the ink composition of the present invention is a solvent-based ink, the organic solvent preferably contains one or more selected from the group consisting of ether compounds, esters, ketones, alcohols, and hydrocarbon compounds. It is more preferable that the organic solvent contains one or more selected from the group consisting of ether compounds and esters. In particular, it is preferable that the organic solvent contains one or more selected from glycol ethers and cyclic esters, and glycol ethers are particularly preferable.

In particular, it is more preferable to include one or more selected from the group consisting of diethylene glycol diethyl ether, tetraethylene glycol monobutyl ether, and gamma-butyrolactone.

This makes it possible to improve the dispersion stability of the metal particles in the ink composition, and the gloss and abrasion resistance of the colored body produced using the ink composition. It also makes it possible to improve the moisture retention of the ink composition, and for example, when the ink composition is an inkjet ink, it is possible to more effectively prevent the solid content of the ink composition from unintentionally precipitating due to drying in an inkjet head or the like. It also makes it possible to more suitably adjust the viscosity of the ink composition.

In particular, when the ink of the present invention is a solvent-based composition containing an organic solvent as a main liquid medium component, the proportion of the organic solvent in all the liquid medium components constituting the metal pigment composition of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, still more preferably 60% by mass or more, and even more preferably 70% by mass or more, with the upper limit being 100% by mass or less.
The lower limit of the content of the organic solvent relative to the total amount of the ink composition is also preferably within the above range, and the upper limit is also preferably 99 mass % or less.
This makes the above-mentioned effects more pronounced.

When the ink composition of the present invention is a solvent-based composition, the content of water in the total liquid medium components is less than 30% by mass. Furthermore, the content of water in the total liquid medium components is preferably sufficiently low, more specifically, preferably 5.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.1% by mass or less. The lower limit is 0% by mass.
The content of water relative to the total amount of the ink composition may be within the above range.

When the ink composition of the present invention is an aqueous composition containing water as the main liquid medium component, the liquid medium component may contain an organic solvent in addition to water.

In the case of an aqueous composition, the proportion of organic solvent in the total liquid medium components is preferably 70% or less, more preferably 50% or less, even more preferably 40% or less, and even more preferably 30% or less. The lower limit is 0% or more, and may be 10% or more.

When the ink composition of the present invention is a water-based composition, the organic solvent contained together with the water is preferably a liquid component that is soluble in water, i.e., a water-soluble organic solvent.

This makes it possible to improve the dispersion stability of the metal particles in the ink composition, and the gloss and abrasion resistance of the colored body produced using the ink composition. In addition, the moisture retention of the ink pigment composition can be improved, and, for example, the solid content of the ink composition can be more effectively prevented from unintentionally precipitating due to drying in an inkjet head or the like. In addition, the viscosity of the ink composition can be more suitably adjusted.

The water-soluble organic solvent may be any water-soluble liquid component, but for example, a liquid component with a solubility in water of 2 g/100 g water or more at 25°C can be preferably used.

The boiling point of the water-soluble organic solvent at 1 atmosphere is preferably 110°C or higher and 300°C or lower.

This can further improve the moisture retention of the ink composition, and for example, when the ink composition is an inkjet ink, it can more effectively prevent the solid content of the metal pigment composition from unintentionally precipitating due to drying in an inkjet head or the like. As a result, the ejection stability of the ink composition by the inkjet method can be further improved. In addition, after the ink composition is ejected, it can be relatively easily volatilized when necessary, and it can more effectively prevent liquid medium components from unintentionally remaining in a colored body produced using the ink composition.

When the ink composition of the present invention is a water-based composition, examples of the water-soluble organic solvent contained together with water include polyols, glycol ethers, amides, and alcohols.
Polyols are compounds having divalent or higher hydroxyl groups, and examples thereof include trivalent or higher polyols, glycols, and alkanediols having 5 or more carbon atoms.
An example of a trihydric or higher polyol is glycerin.
Examples of the glycols include alkanediols having 4 or less carbon atoms, and alkanediols in which hydroxyl groups are condensed between molecules. Examples of the glycols include ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol.
Examples of alkanediols having 5 or more carbon atoms include 1,2-pentanediol and 2-hexanediol.
Examples of the glycol ethers include glycol diethers and glycol monoethers, and glycol monoethers are preferred. Examples of the glycol monoethers include triethylene glycol monobutyl ether.

Examples of the amides include cyclic amides and non-cyclic amides, and examples of the cyclic amides include lactams, etc. Examples of the lactams include 2-pyrrolidone, etc.
Examples of the alcohol include monohydric alcohols. Examples of the monohydric alcohols include ethanol, methanol, propanol, isopropanol, butanol, and phenoxyethanol.
The organic solvent may be used alone or in combination of two or more selected from these.

When the ink composition of the present invention is an aqueous composition, the proportion of water in all the liquid medium components constituting the ink composition of the present invention is 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and even more preferably 55% by mass or more. When the ink composition of the present invention is an aqueous composition, the upper limit of the proportion of water in all the liquid medium components constituting the ink composition of the present invention is 100% by mass.

The lower limit of the water content relative to the total mass of the ink composition may be within the above range, and the upper limit may be 99% by mass or less.

The lower limit of the content of the liquid medium component in the ink composition of the present invention is preferably 50% by mass or more, more preferably 60.0% by mass, even more preferably 70.0% by mass, and even more preferably 75.0% by mass. The upper limit of the content of the liquid medium component in the ink composition of the present invention is not particularly limited, but is preferably 99.7% by mass, more preferably 99.5% by mass, and even more preferably 99.0% by mass.
This allows the viscosity of the ink composition to be more suitable.

[1-5] Other Components The ink composition of the present invention may contain components other than those described above. Hereinafter, these components are also referred to as "other components." Examples of such components include surface treatment agents other than the specific surface treatment agent, leveling agents, binders, dispersants, surfactants, penetration enhancers, moisturizing agents, colorants, fixing agents, antifungal agents, preservatives, antioxidants, chelating agents, thickeners, etc.

The binder may be any resin, and preferred examples include acrylic resins, polyester resins, urethane resins, and cellulose resins. The acrylic resin is a resin obtained by polymerizing at least an acrylic monomer, and may be a copolymer resin of an acrylic monomer and another monomer. Examples of other monomers include vinyl monomers.

Preferred examples of surfactants include silicone-based surfactants and acetylene glycol-based surfactants.

However, the content of other components in the ink composition of the present invention is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less.

The composition used in the preparation of the coloring composition is a composition for obtaining a coloring composition by mixing the composition with other components necessary for the coloring composition. The composition used in the preparation of the coloring composition is also called a pigment dispersion liquid or pigment dispersion used in the preparation of the coloring composition. Therefore, the content of the metal pigment in the composition used in the preparation of the coloring composition is greater than the content of the metal pigment in the coloring composition obtained using the composition used in the preparation of the coloring composition.

The upper limit of the viscosity of the metal pigment composition of the present invention at 25°C measured using a rotational viscometer in accordance with JIS Z8809 is not particularly limited, but is preferably 25 mPa·s, and more preferably 15 mPa·s. The lower limit of the viscosity of the metal pigment composition of the present invention at 25°C measured using a rotational viscometer in accordance with JIS Z8809 is not particularly limited, but is preferably 1.5 mPa·s.

For example, if the metal pigment composition is an ink that is ejected by an inkjet method, this allows the ink to be more suitably ejected in droplets by the inkjet method.

[2] Recording Medium The recording medium is an object to be colored by depositing the ink composition, that is, an object to be colored.

Examples of the recording medium include ink-absorbent recording media such as paper and fabric, which have a recording surface that easily absorbs ink.
Examples of paper include ordinary paper, paper specifically for inkjet printing, and cardboard.
As the fabric, natural or synthetic fibers such as cotton, polyester, or wool, or nonwoven fabric, etc. can be used.
Other examples include non-absorbent recording media made of plastic materials, metals, glass, ceramics, wood, etc. These are recording media whose recording surfaces do not easily absorb ink.
Examples of recording media made of plastic materials include plastic films, plastic sheets, etc. Examples of plastics include, but are not limited to, vinyl chloride, polyester, polyethylene, etc. Examples of polyesters include polyethylene terephthalate, etc.

There are also low-absorbency recording media. These are recording media whose recording surface has the second lowest absorbency after non-absorbency recording media. Low-absorbency recording media include recording media with a coating layer (receptive layer) on the surface for receiving liquid, such as printing paper, whose base material is paper. The coating layer is difficult to absorb ink, and examples of such coating layers include those coated with particles of inorganic compounds and the like together with a binder.

A low-absorbency or non-absorbency recording medium is a recording medium that does not absorb liquid at all or absorbs very little liquid. For example, a non-absorbency or low-absorbency recording medium is preferably a recording medium that has a water absorption of 10 mL/ ^m2 or less from the start of contact to 30 msec1 ^/2 in the Bristow method.
The Bristow method is the most widely used method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Pulp and Paper Technical Association (JAPAN TAPPI). Details of the test method are described in Standard No. 51 "Paper and paperboard - Liquid absorbency test method - Bristow method" of "JAPAN TAPPI Paper and Pulp Test Method 2000 Edition".
In contrast, an absorbent recording medium refers to a recording medium that does not fall under the category of non-absorbent or low absorbent.

The shape of the recording medium is not particularly limited and may be any shape, such as a sheet, a plate, or an object.

[3-1] Ink Set The ink set of this embodiment is an ink set that includes the ink composition described above and an inkjet ink composition that is a colored ink that contains a coloring material.
The term "ink set" refers to two or more inks used as a set for recording. Each ink included in the ink set may be contained in a separate ink container, or may be contained in an integrated ink container.
The ink set includes at least one (one type) of the ink composition described above and at least one (one type) of the colored ink composition. Either one or both of the composition and the colored ink composition described above may be included in two or more pieces.

[3-2] Colored Ink The ink set according to this embodiment includes an inkjet ink composition that is a colored ink. The colored ink is an ink that is used to color a recording medium by the colorant contained in the colored ink. The colored ink is also called a colored ink composition.

By using the ink set of this embodiment, it is possible to record an image having a metallic luster and an image colored with a colorant on a recording medium.
In addition, by recording by overlapping the ink composition containing the above-mentioned metallic pigment and the color ink, an image having a metallic luster and colored by the colorant can be recorded. In this case, the metallic luster may be blocked by the colorant, resulting in a poor metallic luster. However, according to the ink set of this embodiment, the ink composition containing the metallic pigment has excellent luster, so that a colored image having excellent metallic luster can be recorded, which is preferable.
The color ink may be similar to the ink composition containing the metallic pigment in terms of other components and composition, except that the color ink contains a colorant instead of the metallic pigment.

[3-3] Colorant The color ink contains a colorant. The colorant is not the above-mentioned metal pigment. Examples of the colorant include dyes and pigments. The colorant is preferably a chromatic colorant such as cyan, yellow, magenta, or an achromatic colorant such as white or black.

The colorant may be either a dye or a pigment, or a mixture. It is preferable that the colorant contains a pigment. The pigment has excellent storage stability such as light resistance, weather resistance, and gas resistance, and from that viewpoint, it is preferable that the pigment is an organic pigment.

Specific examples of pigments that can be used include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments, polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments, dye chelates, dye lakes, nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments, and carbon black. The above pigments can be used alone or in combination of two or more.

Specific examples of pigments include, but are not limited to, the following:

Examples of black pigments include No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. (all manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (all manufactured by Carbon Columbia), 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. (manufactured by CABOT JAPAN KK), Color Black FW1, Color Black 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 140U, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (all manufactured by Degussa) and other carbon blacks.

Examples of yellow pigments include C.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, 167, 172, and 180.

Examples of magenta pigments include C.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. Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50.

Examples of cyan pigments include C.I. Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, and 66, and C.I. Bat Blue 4 and 60.

Pigments other than magenta, cyan, and yellow are not particularly limited, but examples thereof include C.I. Pigment Green 7, 10, C.I. Pigment Brown 3, 5, 25, 26, and C.I. Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, and 63.

Examples of white coloring materials include C.I. Pigment White 1, which is basic lead carbonate, C.I. Pigment White 4, which is made of zinc oxide, C.I. Pigment White 5, which is made of a mixture of zinc sulfide and barium sulfate, C.I. Pigment White 6, which is made of titanium dioxide, C.I. Pigment White 6:1, which is made of titanium dioxide containing other metal oxides, C.I. Pigment White 7, which is made of zinc sulfide, C.I. Pigment White 18, which is made of calcium carbonate, C.I. Pigment White 19, which is made of clay, C.I. Pigment White 20, which is made of titanium mica, C.I. Pigment White 21, which is made of barium sulfate, C.I. Pigment White 22, which is made of gypsum, C.I. Pigment White 26, which is made of magnesium oxide and silicon dioxide, C.I. Pigment White 27, which is made of silicon dioxide, and C.I. Pigment White 28, which is made of anhydrous calcium silicate. Examples of the pigments include C.I. Pigment White 28. Among these, it is preferable to use C.I. Pigment White 6, which has excellent color development and hiding properties.

As dyes, various dyes that are typically used in inkjet recording, such as direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, and reactive disperse dyes, can be used.

When the colored ink contains a pigment as the colorant, it is preferable that the ink contains a dispersant to disperse the pigment. Examples of dispersants include dispersant resins and other surfactants. Alternatively, if the pigment has acidic groups on its surface, it can be a self-dispersing pigment that can be dispersed without a dispersant.

[4] Recording Method Next, the recording method of the present invention will be described.

[4-1] Application Step The recording method of the present invention includes a step (application step) of applying the ink composition containing the above-mentioned metal pigment to a recording medium by an inkjet method in which the ink composition is ejected from an inkjet head.

This makes it possible to provide a recording method that can record records with excellent ejection stability, and furthermore, with ink that has excellent dispersion stability and gloss.

When the ink composition is ejected by the inkjet method, the inkjet method may be a piezoelectric method or a method in which the ink is ejected by bubbles generated by heating the ink, but the piezoelectric method is preferred from the viewpoint of the resistance to deterioration of the metal pigment.

The ink composition can be ejected using the inkjet method using a known droplet ejection device.

The colored portion formed by the ink composition may, for example, have a predetermined pattern, or may be formed over the entire surface of the substrate.

[4-2] Primary Heating Step The recording method according to this embodiment may include a primary heating step, which is a step of quickly heating the ink composition that has been applied to the recording medium.
The primary heating step is a step of heating and drying the ink adhered to the recording medium at an early stage. The primary heating step is a heating step for drying at least a part of the liquid medium of the ink adhered to the recording medium to an extent that at least the flow of the ink is reduced. In the primary heating step, the ink may be adhered to the heated recording medium, or may be heated at an early stage after the ink is adhered to the recording medium.
It is preferable that heating of the ink droplets that have landed on the recording medium be started within 0.5 seconds at the latest after the ink droplets have landed on the recording medium.
The primary heating step is preferably carried out for each ink composition to be deposited. For example, when colored inks are also deposited, the primary heating step is preferably carried out for each ink composition to be deposited.

The primary heating step is preferably performed using an IR heater, microwave radiation, a platen heater, or blowing hot air onto the recording medium using a fan.

The heating in the primary heating step may be carried out at least either before the ink application step, simultaneously with application, or shortly after application, and is preferably carried out simultaneously. The ink application step can be carried out in such a heating order. In particular, it is preferable to heat the recording medium and then apply the ink composition to the heated recording medium in the ink application step.

When the method includes a primary heating step, the ink composition can be dried quickly on the recording medium, which is preferable because it can prevent bleeding of the ink. In particular, bleeding between the ink composition containing a metal pigment and the color ink can be prevented, which is preferable.
On the other hand, when a primary heating step is included, the ink dries quickly, so that the metallic pigment does not have enough time to leaf-in, which may result in poor gloss, and the ink may be subjected to heat in the primary heating step, which may result in poor ejection stability. However, according to the ink composition containing the metallic pigment of this embodiment, excellent gloss and ejection stability can be obtained, which is preferable, even when a primary heating step is included.

The surface temperature of the recording surface of the recording medium in the primary heating step in which the ink composition is heated is preferably 30° C. or higher, and more preferably 60° C. or lower. Further, it is preferably 35° C. or higher and 55° C. or lower, and even more preferably 40° C. or higher and 50° C. or lower. When the surface temperature of the recording medium is in the above-mentioned mode, bleeding is prevented and ejection stability is more excellent, which is preferable.
The surface temperature of the recording medium in the primary heating step is the surface temperature of the recording medium when the ink is applied, or, if heating is performed after application, the temperature of the recording medium at the time of heating. It is also the maximum temperature during recording.

[4-3] Post-Heating Step The recording method according to this embodiment may include a post-heating step (secondary heating step) of heating the recording medium after the ink application step.
The post-heating step is a heating step for heating the recording medium sufficiently to complete the recording and make the recorded matter usable. The post-heating step is a heating step for sufficiently drying the solvent component of the ink. The post-heating step is preferably started more than 0.5 seconds after the ink is attached to the recording medium. For example, it is preferable to start heating a certain recording area of the recording medium more than 0.5 seconds after the ink is completely attached to the area.
The recording medium can be heated in the post-heating step by using, for example, an appropriate heating means. In this case, the surface temperature of the recording medium is preferably 50° C. or higher, more preferably 60° C. or higher, 70° C. or higher, or 75° C. or higher. Although there is no upper limit, it is preferably 120° C. or lower. In addition, the heating temperature is preferably equal to or lower than the softening point of the substrate of the recording medium.

[4-4] Order of ink application steps The recording method of this embodiment may include an application step of applying the above-mentioned color ink. In this case, the order in which the ink application steps are performed is not particularly limited. The ink composition containing the metallic pigment may be applied before the color ink, or the color ink may be applied before the ink composition containing the metallic pigment. In addition, the ink composition containing the metallic pigment and the color ink may be applied to different locations on the recording medium, or may be applied to the same location in a superimposed manner.
By depositing the ink composition containing the metallic pigment and the color ink on the same location in layers, an image having a metallic luster and colored by the colorant can be recorded, which is preferable. In particular, it is preferable to deposit the ink composition containing the metallic pigment first, and then deposit the color ink on top of the layer of the ink composition containing the metallic pigment that has been deposited, since this provides better coloring of the image having a metallic luster and colored by the colorant.

In a recording area where the ink composition containing a metallic pigment and the color ink are adhered in an overlapping manner, the adhesion amount of the ink composition containing a metallic pigment per unit area is preferably 1 to 10 mg/ ^inch2 , and more preferably 2 to 7 mg/ ^inch2 . The adhesion amount of the color ink in the recording area is preferably 0.1 to 7 mg/ ^inch2 , and more preferably 0.5 to 5 mg/ ^inch2 . In addition, in a recording area where the ink composition containing a metallic pigment and the color ink are adhered in an overlapping manner, the maximum adhesion amount of the ink composition containing a metallic pigment and the maximum adhesion amount of the color ink may each be within the above-mentioned ranges, and are preferable.

[5] Recording Apparatus A recording apparatus according to one embodiment of the present invention includes a recording head that ejects the ink composition containing the metal pigment described above and deposits it onto a recording medium, and a recording head that ejects the colored ink and deposits it onto a recording medium, and performs recording by the recording method described above.

An example of a recording device according to this embodiment will be described with reference to the drawings.

[5-1] Overview of the Device Configuration Fig. 1 is a schematic cross-sectional view showing a recording device. As shown in Fig. 1, the inkjet recording device 1 includes a recording head 2, an IR heater 3, a platen 4, a heater 5, a cooling fan 6, a pre-heater 7, and a ventilation fan 8. The recording head is mounted on a carriage (not shown) and performs a main scan in the back-to-front direction of the figure to deposit ink on a recording medium M. The platen 4 is provided with a platen heater (not shown). The recording device 1 includes a control unit (not shown) that controls each unit to perform recording. The recording head 2 receives a supply of ink from an ink container (not shown).

[5-2] Configuration Related to Inkjet Head The recording head 2, which is an inkjet head, is configured to perform recording on a recording medium M by ejecting and depositing an ink composition from the nozzles of the recording head 2. The recording head 2 shown in FIG. 1 is a serial type recording head, which scans multiple times in the main scanning direction relative to the recording medium M to deposit ink on the recording medium M. The recording head 2 is mounted on a carriage (not shown). The recording head 2 is scanned multiple times in the main scanning direction relative to the recording medium M by the operation of a carriage movement mechanism that moves the carriage in the medium width direction of the recording medium M (back-to-front direction in the figure). The medium width direction is the main scanning direction of the recording head 2. Scanning in the main scanning direction is also called main scanning.

Here, the main scanning direction is the direction in which the carriage carrying the recording head 2 moves. In FIG. 1, it is the direction that intersects with the sub-scanning direction, which is the transport direction of the recording medium M, indicated by the arrow SS. Then, recording is performed on the recording medium M by repeating the main scanning of the recording head 2 and the sub-scanning, which is the transport direction of the recording medium M, multiple times.

The recording head 2 can use a conventional method for ejecting ink. For example, a method of ejecting ink droplets using the vibration of a piezoelectric element, i.e., an ejection method of forming ink droplets by mechanically deforming an electrostrictive element, can be used.

[5-3] Primary Heating Mechanism The inkjet recording device 1 may include a primary heating mechanism that performs a primary heating step of heating the recording medium M when ink is discharged from the recording head 2 and adhered to the recording medium. The primary heating mechanism may be of a conduction type, an air blowing type, a radiation type, or the like. The conduction type conducts heat to the recording medium from a member that contacts the recording medium. For example, a platen heater or the like may be used. Although the platen heater is not shown, it is provided integrally with the platen 4. The air blowing type sends normal temperature air or hot air to the recording medium to dry the ink. For example, a blower fan may be used. The radiation type radiates radiation that generates heat to the recording medium to heat it. For example, IR radiation may be used. Although not shown, a heater similar to the platen heater may be provided immediately downstream of the platen 4 in the SS direction. These primary heating mechanisms may be used alone or in combination.

For example, the primary heating mechanism includes an IR heater 3 and a platen heater.

When the IR heater 3 is used, the recording medium M can be radiated by radiating infrared rays from the recording head 2 side. This makes it easier for the recording head 2 to heat at the same time, but compared to heating from the back side of the recording medium M using a platen heater or the like, the temperature can be increased without being affected by the thickness of the recording medium M. The primary heating mechanism may also be equipped with various fans (e.g., ventilation fan 8) that blow warm air or air at the same temperature as the environment onto the recording medium M to dry the ink on the recording medium M.

The platen heater can heat the recording medium M through the platen 4 at a position opposite the recording head 2. The platen heater can heat the recording medium M by conduction, and is used as necessary in the inkjet recording method.

The inkjet recording device 1 may also be equipped with a preheater 7 that preheats the recording medium M before the ink is applied to the recording medium M.

[5-4] Post-Heating Mechanism A post-heating mechanism may be provided that performs a post-heating step of heating the recording medium after the white ink application step and the non-white ink application step to dry and fix the ink.

The heater 5 used in the post-heating mechanism dries and solidifies the ink attached to the recording medium M. By heating the recording medium M on which an image has been recorded, the water contained in the ink evaporates and dissipates more quickly, and an ink film is formed by the resin contained in the ink. In this way, the ink film is firmly fixed or adhered to the recording medium M, resulting in excellent film-forming properties, and an excellent, high-quality image can be obtained in a short time.

[5-5] Other Configurations The inkjet recording apparatus 1 may have a cooling fan 6. After the ink recorded on the recording medium M is dried, the ink on the recording medium M is cooled by the cooling fan 6, whereby an ink coating film with good adhesion can be formed on the recording medium M.

The recording device shown in FIG. 1 is a serial printer that records using a so-called serial method. The recording device may also be a line printer that has a line head and records using a line method.

The line head includes a nozzle row in which a plurality of nozzles are arranged in the width direction of the recording medium, has a length equal to or greater than the width of the recording medium M being transported, and can record an image in a single pass in the width direction of the recording medium M being transported. Then, recording can be performed in a single scan. Alternatively, after one scan in which the recording medium is transported, the recording medium can be returned in the opposite direction to the transport direction and transported again to perform another scan, thereby performing recording in two or more scans.
Scanning may be performed by a head whose position is fixed relative to the conveyed recording medium, or scanning may be performed while the head moves relative to the recording medium fixed in the platen area.

Note that a recording device capable of performing line-type recording can have the same configuration as shown in FIG. 1, except that the recording head 2 is changed to a line head. Specifically, heating mechanisms such as the ventilation fan 8, IR heater 3, platen heater, and pre-heater 7 above the recording head 2 shown in FIG. 1 can be provided above or below the line head in the same way. In addition, a post-heating mechanism such as the heater 5 and cooling fan 6 shown in FIG. 1 may also be provided.

The present invention has been described above based on preferred embodiments, but the present invention is not limited to these.

Next, specific examples of the present invention will be described.
(Example A1)
First, a polyethylene terephthalate film having a thickness of 20 μm and a smooth surface with a surface roughness Ra of 0.02 μm or less was prepared.

Next, a release resin that had been solubilized with acetone was coated on the entire surface of one side of the film using a roll coater to form a release layer.

The polyethylene terephthalate film with the release layer formed was transported into a vacuum deposition device at a speed of 5 m/s, and a 16 nm thick film composed of Al was formed under reduced pressure.

Next, the polyethylene terephthalate film on which the Al film was formed was immersed in tetrahydrofuran and subjected to ultrasonic vibrations of 40 kHz, resulting in a dispersion of a metal pigment that is an aggregate of Al metal particles.

Next, the tetrahydrofuran was removed using a centrifuge, and diethylene glycol diethyl ether was added to obtain a suspension with a metal pigment content of 5% by mass.

Next, this suspension was treated with a circulating high-power ultrasonic grinder to crush the metal particles to a specified size. In this treatment, ultrasonic waves of 20 kHz were applied.

Next, the suspension was heat-treated at 55°C for 2 hours under ultrasonic irradiation at 40 kHz to break down the agglomerates of the metal particles and disperse them in the form of primary particles. A specific surface treatment agent, which is a compound represented by the above formula (1), was added to the suspension in such a ratio that the mass ratio to the metal particles was the value in Table 1. In this example, the specific surface treatment agent used was a mixture of a compound in which R is a tridecyl group and a is 1, and a compound in which a is 2, in the above formula (1).

Then, the metal particles were subjected to a heat treatment at 55°C for 5 hours under irradiation with 28 kHz ultrasonic waves to react with the specific surface treatment agent on the surface of the metal particles, thereby obtaining a dispersion of metal particles whose surfaces were modified with the specific surface treatment agent.

Then, diethylene glycol diethyl ether, tetraethylene glycol monobutyl ether, γ-butyrolactone, and resin were added to the obtained dispersion liquid of metal particles to obtain the inkjet ink composition A1 shown in Table 1. This was a solvent-based composition.

The metal particles contained in the ink composition thus obtained had a volume average particle diameter of 0.40 μm and an average thickness of 16 nm.

(Examples A2~)
A metallic pigment dispersion was prepared by using a metallic pigment having the composition shown in Table 1, and by replacing the surface treatment agent used in the preparation of the metallic pigment dispersion with that shown in Table 1. Comparative ink compositions from A2 onwards were produced in the same manner as in Example A1, except that the obtained metallic pigment dispersion and the remaining components shown in Table 1 were used to obtain the composition shown in Table 1 by changing the types and ratios of the raw materials contained. The average thickness of the metallic particles was adjusted during deposition of Al. The average particle size of the metallic particles was adjusted by adjusting the amount of grinding during ultrasonic grinding.

(Example B1)
The metal pigment dispersion obtained in the preparation of the metal pigment dispersion in Example A1 was used, and diethylene glycol diethyl ether was replaced with water to obtain an aqueous dispersion of the metal pigment containing 5% by mass of metal particles surface-modified with a specific surface treatment agent.
To the resulting pigment dispersion were added water, 1,2-hexanediol, propylene glycol, and a urethane resin (Rezamin D1060, manufactured by Dai-Nippon Seika Kogyo Co., Ltd.) to obtain the ink composition B1 shown in Table 2. This was a water-based ink.

The volume average particle diameter of the metal particles contained in the metal pigment composition obtained in this manner was 0.40 μm, and the average thickness was 16 nm.

(Examples B2~)
A metallic pigment dispersion was prepared by using the metallic pigment as shown in Table 2, and by replacing the surface treatment agent used in the preparation of the metallic pigment dispersion with that shown in Table 2. Using the obtained metallic pigment dispersion and the remaining components shown in Table 2, the ink compositions from Example B2 onwards and the comparative examples were produced in the same manner as in Example B1, except that the composition shown in Table 2 was obtained by changing the types and ratios of the raw materials contained using the obtained metallic pigment dispersion and the remaining components shown in Table 2. The average thickness of the metallic particles was adjusted during deposition of Al. The average particle size of the metallic particles was adjusted by adjusting the amount of grinding during ultrasonic grinding.

The constitution and composition of the metal pigment contained in the ink composition for each of the above examples and comparative examples are summarized in Tables 1 and 2. Each component is described below. The carbon number of R in the treatment agent in the table indicates the number of carbon atoms in the carbon skeleton of R.

Tridecyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-tridecyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Isotridecyl phosphate: a surface treatment agent represented by the above formula (1), in which R in formula (1) is an isotridecyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Cetyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-cetyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Octadecyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-octadecyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Octadecylphosphonic acid: A surface treatment agent represented by the above formula (2), in which R in formula (2) is an n-octadecyl group.
Oleyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-oleyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Tetracosyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-tetracosyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Octyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-octyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Dodecyl phosphate: A surface treatment agent represented by the above formula (1), in which R in formula (1) is an n-dodecyl group, and a mixture of a compound in which a is 1 and a compound in which a is 2.
Dodecylphosphonic acid: A surface treatment agent represented by the above formula (2), in which R in formula (1) is an n-dodecyl group.
16-Phosphonohexadecanoic Acid: A surface treatment agent represented by the above formula (2), in which R in formula (1) is a 16-carboxy-n-hexadecyl group.
FHP: 2-(perfluorohexyl)ethylphosphonic acid. A surface treatment agent that is not a specific surface treatment agent.
ODTMS: Octadecyltrimethoxysilane. A surface treatment agent that is not a specific surface treatment agent.
Paraloid B60: Acrylic resin manufactured by The Dow Chemical Company.
DEDG: Diethylene glycol diethyl ether.
BTGH: Tetraethylene glycol monobutyl ether.
γBL: γ-butyrolactone.
D1060: Urethane resin. Resamine D1060 manufactured by Dai-Nippon Seika Kogyo Co., Ltd.
1,2HD: 1,2-hexanediol.
PG: Propylene glycol.
P. B. 15:3: Pigment Blue 15:3.

Colored inks shown in A18 in Table 1 and B9 in Table 2 were also prepared. In preparing the colored inks, a dispersion was prepared in advance by dispersing the pigment using a dispersant not listed in the table, and this was used to prepare the inks. The dispersant used was a polyester polyamide resin for A18, and an acrylic styrene resin for B9. The pigment:dispersant was mixed in a mass ratio of 2:1 and thoroughly stirred in a bead mill to prepare a pigment dispersion. The dispersion medium was diethylene glycol diethyl ether for A18, and water for B9.
In the table, the unit of the content of each component is mass %. For the metal pigment constituting the ink composition of the previous example, the volume average particle diameter D (D50) in the table was measured using a Microtrac MT-3300 (a laser diffraction/scattering type particle size distribution measuring device manufactured by Microtrac Bell). The average thickness T was measured by atomic force microscopy using a NanoNavi E-Sweep (manufactured by SII Nano Technology Co., Ltd.).
The viscosity of the ink composition of each example at 25° C., measured using a rotational viscometer in accordance with JIS Z8809, was in the range of 1.5 mPa·s to 15 mPa·s.

(evaluation)
A recording device was prepared. A modified version of the Seiko Epson SC-S80650 was used. The nozzle density of the nozzle row of the inkjet head was set to 360 npi, with 360 nozzles. The inkjet head was filled with ink. The drive waveform of the inkjet head was optimized to perform optimal ejection of the filled ink.
During recording, the platen heater was controlled to heat the surface temperature of the recording medium on the platen during recording to the heating temperature (° C.) shown in the table as the primary heating step.
During recording, an after-heater was operated to carry out a post-heating process, and the surface temperature of the recording medium in the post-heating process was set to 50° C. For recording, a polyvinyl chloride film (Mactac 5829R, manufactured by Mactac Corporation) was used as the recording medium.
When recording, the amount of ink attached in the recording pattern was 5 mg/inch ² , and the recording resolution was 1440×1440 dpi.

(Discharge characteristics)
Before recording, we checked whether the ink could be ejected stably from the inkjet head. This was a test to check the ejection stability.
During the test, the platen heater of the recording device was not operated, and ink was ejected from the inkjet head, which was fixed in position, to the ink receiver. The inkjet head was driven at an ejection frequency of 4 kHz to eject ink continuously. The test was carried out in an environment of 30° C. and 50% RH.
The ink droplets flying downward from the nozzle were photographed from the side with a camera to confirm the flight state of the ink droplets. The continuously ejected ink droplets were photographed at a predetermined time interval to confirm the position of the ink droplets during flight. The position was confirmed 20 seconds after the start of continuous ejection at a position 0.8 mm from the nozzle in the ejection direction.
Although each nozzle was ejecting ink at the same time, some nozzles had ink droplets that were offset in the ejection direction from the other nozzles. In the captured image, nozzles with ink droplets that were offset by 30% or more from the distance between successively ejected ink droplets were determined to have flight speed deviations. The results are shown in Tables 1 and 2.

A: The number of nozzles with deviation in flight speed is 2% or less of the total number of nozzles.
B: The number of nozzles with deviation in flight speed is more than 2% but not more than 5% of the total number of nozzles.
C: The number of nozzles with deviation in flight speed is more than 5% but not more than 8% of the total number of nozzles.
D: The number of nozzles with deviation in flight speed exceeds 8% of the total number of nozzles.

(Dispersion stability)
The ink compositions prepared in the above examples were each placed in a container and sealed, and the container was left in a thermostatic chamber at 45° C. for 10 days, and then gradually cooled to room temperature.

These ink compositions were then measured using a particle size distribution meter (Microtrac, MT3300EXII) to determine the volume average particle diameter D50 of the metal particles, and the rate of increase from the volume average particle diameter D50 of the metal particles contained in the metal pigment composition before it was placed in the thermostatic bath was determined and evaluated according to the following criteria. The smaller the rate of increase in the volume average particle diameter D50, the better the dispersion stability of the metal particles. The results are shown in Tables 1 and 2.

A: The increase rate is within 2%.
B: The increase rate is more than 2% and not more than 4%.
C: The increase rate is more than 4% and not more than 7%.
D: The increase rate is more than 7% and not more than 10%.
E: The increase rate is more than 10%.

(Glossiness)
A recording test was carried out under the above conditions using the recording device described above. The gloss of the recorded portion of the recorded matter thus obtained was measured at a tilt angle of 60° using a gloss meter, MINOLTA MULTI GLOSS 268, and evaluated according to the following criteria. The higher this value, the better the metallic gloss. Note that the solvent-based ink and the water-based ink have different types of solvents, which results in differences in overall glossiness, so the evaluation criteria were different. The results are shown in Tables 3 and 4.

(Evaluation criteria for the examples in Table 3)
A: The gloss level is 350 or more.
B: Glossiness is 300 or more and less than 350.
C: Glossiness is 270 or more and less than 300.
D: Glossiness is 240 or more and less than 270.
E: The gloss level is less than 240.

(Evaluation criteria for the examples in Table 4)
A: The gloss level is 250 or more.
B: The gloss level is 200 or more and less than 250.
C: The gloss level is less than 200.

(Discharge test)
The above recording test was carried out continuously for one hour. After recording, a nozzle inspection was carried out to check for nozzle ejection defects, i.e., non-ejection or landing position deviation. An impact position deviation of 30% or more of the nozzle distance from the correct position was deemed defective. This test was carried out to check the ejection stability during recording. The results are shown in Tables 3 and 4.

A: The ejection failure rate was 2% or less of the total number of nozzles.
B: The ejection failure rate is more than 2% and not more than 4% of the total number of nozzles.
C: The ejection failure occurred in more than 4% to 7% of the total number of nozzles.
D: Discharge defects exceed 7% of the total number of nozzles.

(Evaluation of Ink Set)
The ink sets shown in Tables 5 and 6 were constructed by combining an ink containing a metallic pigment (metallic ink) and a color ink. In the above recording test, the ink containing a metallic pigment and the color ink were filled in separate nozzle rows and recording was performed. First, the ink containing a metallic pigment was applied at an adhesion amount of 5 mg/ ^inch2 , and then the recording medium was rewound and the color ink was applied on top of the ink containing a metallic pigment at an adhesion amount of 1 mg/ ^inch2 . In this way, recording was performed in the same manner as in the above recording test. The recorded matter obtained in this way had a metallic luster and a color metallic color colored with the color of the color ink in the recorded portion.
The gloss of the recorded portion was measured in the same manner as described above. Since the gloss was generally lower than that of the recorded matter recorded using only the ink containing the above-mentioned metallic pigment, the evaluation criteria were as follows. The results are shown in Tables 5 and 6.

(Evaluation criteria for the examples in Table 5)
A: The gloss level is 200 or more.
B: Glossiness is 150 or more and less than 200.
C: Glossiness is less than 150.

(Evaluation criteria for the examples in Table 6)
A: The gloss level is 150 or more.
B: The gloss level is 100 or more and less than 150.
C: The gloss level is less than 100.

As is clear from the table, each of the examples using the ink composition containing the metallic pigment of the present invention had excellent ejection stability. Furthermore, the dispersion stability and glossiness were also excellent. Furthermore, the ink set including the ink composition containing the metallic pigment of the present invention also had excellent color metallic gloss.
In contrast, all of the comparative examples not using the metallic pigment composition of the present invention were inferior in ejection stability, and the ink sets not including the ink composition containing the metallic pigment of the present invention were inferior in color metallic gloss.

The same evaluation was carried out as above, except that a polyethylene terephthalate film (E1000ZC, manufactured by Lintec Corporation) was used instead of a polyvinyl chloride film (Mactac 5829R, manufactured by Mactac Corporation) as the recording medium, and the same results were obtained.

For example, the following can be derived from the above-described embodiment:

An ink-jet ink composition comprising a metal pigment and a liquid medium component, the metal pigment being composed of metal particles, the metal particles being surface-modified with a surface treatment agent, the surface treatment agent being at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), and the ink-jet ink composition being a water-based ink or a solvent-based ink.
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is 1 or 2.)

An inkjet ink composition in which the surface treatment agent is represented by formula (1) or (2), where R is a chain-like aliphatic hydrocarbon group.

The surface treatment agent is an inkjet ink composition, wherein R in formula (1) or (2) is a hydrocarbon group having no substituent, and the inkjet ink composition is a solvent-based ink.

An inkjet ink composition that is a solvent-based ink containing an organic solvent as the liquid medium, or a water-based ink containing water as the liquid medium.

The surface treatment agent is an inkjet ink composition, wherein R in formula (1) or (2) is a hydrocarbon group having a substituent, and the inkjet ink composition is a water-based ink.

An inkjet ink composition, wherein the metal particles are composed of aluminum or an aluminum alloy.

An inkjet ink composition, in which the metal particles are scaly.

An inkjet ink composition in which the content of the surface treatment agent is 1.0 part by mass or more and 50 parts by mass or less per 100 parts by mass of the metal particles.

An inkjet ink composition in which the surface treatment agent is represented by formula (1) or (2), where R has a carbon skeleton having 15 or more carbon atoms.

An ink set comprising the above inkjet ink composition and an inkjet ink composition that is a colored ink containing a coloring material.

A recording method comprising a deposition step of ejecting the inkjet ink composition from an inkjet head and depositing it on a recording medium.

A recording method including a primary heating step of heating the ink composition applied in the application step.

The recording method further includes a deposition step in which an inkjet ink composition, which is a colored ink containing a coloring material, is ejected from an inkjet head and deposited on a recording medium, thereby forming a colored image with a metallic luster.

1... Inkjet recording device, 2... Recording head, 3... IR heater, 4... Platen, 5... Heater, 6... Cooling fan, 7... Pre-heater, 8... Ventilation fan.

Claims (13)

The ink-jet ink composition is discharged from an ink-jet head and deposited on a recording medium.
and
a primary heating step of heating the ink composition deposited in the depositing step,
1. A method comprising:
The ink-jet ink composition contains a metal pigment and a liquid medium component .
the ink is a water-based ink, the liquid medium component of which contains water , or a solvent-based ink, the liquid medium component of which contains an organic solvent ;
It is not a photocurable ink that is cured by exposure to light.
The solvent-based ink contains one selected from glycol ethers and cyclic esters.
A solvent-based ink containing the above organic solvent,
The metal pigment is made of metal particles,
the metal particles are surface-modified with a surface treatment agent;
The surface treatment agent is at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2),
The primary heating step includes heating a platen at a position facing the inkjet head.
A recording method in which the supported recording medium is heated .
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is 1 or 2.) 2. The recording method according to claim 1, wherein in the surface treatment agent, R in the formula (1) or (2) is a chain aliphatic hydrocarbon group. 3. The recording method according to claim 1, wherein in the surface treatment agent, R in formula (1) or (2) is a hydrocarbon group having no substituent, and the ink-jet ink composition is a solvent- based ink . The primary heating step is a step of conducting heat from the platen to a recording medium supported by the platen.
The recording method according to any one of claims 1 to 3 , wherein the recording is performed by The inkjet ink composition is a solvent-based ink,
Contains one or more organic solvents selected from glycol ethers and cyclic esters
The amount of the liquid medium component is 50% by mass or more based on the total amount of the liquid medium components.
The recording method according to claim 1. 6. The recording method according to claim 1, wherein the metal particles are made of aluminum or an aluminum alloy. 7. The recording method according to claim 1, wherein the metal particles are scaly.
Law. 8. The recording method according to claim 1, wherein the content of the surface treatment agent is 1.0 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the metal particles. 9. The recording method according to claim 1, wherein in the surface treatment agent, R in formula (1) or (2) has a carbon skeleton having 15 or more carbon atoms. The ink-jet ink composition, which is a colored ink containing a coloring material , is sprayed from an ink-jet head.
The method according to any one of claims 1 to 9, further comprising a step of ejecting the ink from a nozzle and depositing the ink on a recording medium .
The recording method according to claim 1. In the first heating step, the surface temperature of the recording surface of the recording medium is 50° C. or less.
The recording method according to any one of claims 1 to 10 . The method further includes a step of ejecting an ink-jet ink composition, which is a color ink containing a coloring material , from an ink-jet head and depositing the ink on a recording medium,
The recording method according to any one of claims 1 to 11 , wherein a colored image having a metallic luster is formed. Contains a metal pigment and a liquid medium component,
The metal pigment is made of metal particles,
the metal particles are surface-modified with a surface treatment agent;
The surface treatment agent is selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2).
At least one selected from the group consisting of
The surface treatment agent is represented by the formula (1) or (2), wherein R is a hydrocarbon group having a substituent,
The ink-jet ink composition is a water-based ink.
(RO) _a P(O)(OH) _3-a (1)
(R)P(O)(OH) ₂ (2)
(In the formula, R is independently a hydrocarbon group having a carbon skeleton having 13 or more carbon atoms, and a is
, 1 or 2.)

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