Recording method and recording device

Abstract

To provide a recording method and a recording device effectively preventing unintentional precipitation or the like of metallic pigment in an inkjet head, and capable of stably producing a recorded matter excellent in glossy feeling.SOLUTION: A recording method for recording in a recording medium by using a recording device including an inkjet head includes a step of discharging an inkjet composition from the inkjet head. The inkjet composition contains metallic pigment, and the metallic pigment comprises a plurality of scaly metallic particles. The inkjet head has a circulation passage for circulating the inkjet composition, and an average thickness of the metallic particles determined by an atomic force microscope is 19 nm or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a recording method and a recording apparatus. [Background technology]

[0002] BACKGROUND ART Conventionally, metal plating, foil stamping using metal foil, thermal transfer using metal foil, and the like have been used as methods for manufacturing decorative articles with a glossy appearance.

[0003] However, these methods have problems such as difficulty in forming fine patterns and application to curved surfaces.

[0004] On the other hand, a recording method is used in which a composition containing a pigment or dye is applied to a recording medium by an inkjet method, which is advantageous in that it can be suitably applied to the formation of fine patterns and recording on curved surfaces.

[0005] A method for producing a recorded matter using ink containing silver particles, which are metal particles, instead of ordinary pigments or dyes has been proposed, with the aim of obtaining a recorded matter that exhibits high metallic luster and specularity (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-103616 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when ink containing metal particles is applied to the inkjet method, a problem occurs in that the metal particles in the ink settle inside the inkjet head.

[0008] In particular, when the metal particles are scaly particles, they are likely to become locally retained within the inkjet head and to sediment.

[0009] This causes a problem that the concentration of metal particles in the ink ejected from the inkjet head becomes non-uniform, and the metallic luster of the resulting printed matter is not stable. [Means for solving the problem]

[0010] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0011] A recording method according to an application example of the present invention is a recording method for recording on a recording medium using a recording apparatus equipped with an inkjet head, ejecting the inkjet composition from the inkjet head; the composition for inkjet contains a metal pigment, the metal pigment is composed of a plurality of scale-like metal particles, the inkjet head is provided with a circulation flow path for circulating the inkjet composition, The metal particles have an average thickness of 19 nm or less as determined by atomic force microscopy.

[0012] In a recording method according to another application example of the present invention, the content of the metal particles in the composition for inkjet is 0.2% by mass or more and 4.0% by mass or less.

[0013] In a recording method according to another application example of the present invention, the metal particles are made of a material containing aluminum or an aluminum alloy.

[0014] In a recording method according to another application example of the present invention, the metal particles are surface-treated with a phosphorus compound or a silicon compound.

[0015] In a recording method according to another application example of the present invention, the metal particles have a volume average particle diameter D50 of 0.20 μm or more and 1.00 μm or less.

[0016] In addition, in a recording method according to another application example of the present invention, the average aspect ratio of the metal particles, which is the ratio of the volume average particle diameter D50 of the metal particles to the average thickness of the metal particles determined by atomic force microscopy, is 20 or more and 2000 or less.

[0017] In a recording method according to another application example of the present invention, the metal particles have an average thickness of 5 nm or more and 19 nm or less as determined by atomic force microscopy.

[0018] In a recording method according to another application example of the present invention, the ink-jet composition is a solvent-based ink.

[0019] In a recording method according to another application example of the present invention, the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow path to the maximum ejection rate of the inkjet head is 0.50 or more and 15 or less.

[0020] Further, a recording apparatus according to an application example of the present invention includes an inkjet head, the inkjet head is provided with a circulation flow path for circulating the inkjet composition, A recording method according to an application example of the present invention is carried out. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a recording apparatus. [Figure 2] FIG. 2 is a perspective view showing the configuration of the carriage and its surroundings in the recording apparatus shown in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view of an inkjet head of a recording apparatus. [Figure 4] FIG. 4 is a schematic cross-sectional view showing an enlarged view of a portion of the ink-jet head in the vicinity of the circulating liquid chamber. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will be described in detail below. [1] Recording method First, the recording method of the present invention will be described.

[0023] The recording method of the present invention is a recording method for recording on a recording medium using a recording device equipped with an inkjet head, and includes a step of ejecting from the inkjet head an inkjet composition containing a metal pigment composed of a plurality of scale-like metal particles. The inkjet head is equipped with a circulation flow path for circulating the inkjet composition. Furthermore, the average thickness of the metal particles measured by atomic force microscopy is 19 nm or less.

[0024] With this configuration, it is possible to provide a recording method that can effectively prevent undesired settling of the metal pigment inside the inkjet head and stably produce recorded matter with excellent gloss.

[0025] The reasons for the above-described excellent effects are believed to be as follows. Specifically, by circulating an inkjet composition containing a metal pigment that satisfies certain conditions in an inkjet head provided with a circulation channel, the metal particles are preferably oriented so that the plane direction of the scaly metal particles, i.e., the direction intersecting the thickness direction of the metal particles, is approximately parallel to the flow direction of the inkjet composition as the inkjet composition flows through the narrow channel in the inkjet head. This preferred orientation of the metal particles reduces flow resistance when the inkjet composition flows through the narrow channel in the inkjet head, allowing for favorable flow and preventing sedimentation of the metal particles. Furthermore, metal pigments containing scaly metal particles may aggregate so that the main surfaces of the metal particles come into contact with each other. Even if such aggregation occurs, the thickness of the metal particles is sufficiently small as described above, which reduces the thickness of the aggregates and favorably prevents blockage of the flow of the metal particles. Furthermore, even if aggregates do form, the aggregates are broken down by circulation through the circulation channel, allowing the inkjet composition to be ejected from the nozzle in an independent state. These factors are believed to be responsible for the above-described excellent effects.

[0026] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, if the metal particles are not scaly, for example, if they are spherical, the gloss of the resulting printed matter will be significantly inferior.

[0027] Furthermore, even if the metal particles are scaly, if their average thickness is too large, aggregation of the metal particles in the inkjet head cannot be sufficiently prevented even if the inkjet head that ejects the inkjet composition is equipped with a circulation flow path, and once aggregates of the metal particles occur, it becomes difficult to break up the aggregated state. As a result, the ejection stability of the inkjet composition by the inkjet method decreases, and recorded matter with excellent gloss cannot be stably produced.

[0028] Furthermore, if the inkjet head that ejects the inkjet composition does not have a circulation flow path, it is not possible to sufficiently prevent the sedimentation and aggregation of metal particles within the inkjet head, and once sedimentation or aggregation of metal particles occurs, it becomes difficult to release the sedimented or aggregated state of the metal particles. As a result, the ejection stability of the inkjet composition by the inkjet method decreases, and it is not possible to stably produce recorded matter with excellent glossiness.

[0029] [1-1] Discharge process In the ejection step, the inkjet composition is ejected from an inkjet head toward a recording medium.

[0030] The inkjet composition discharged in this step contains a metal pigment, which is composed of a plurality of scale-like metal particles, and the average thickness of the metal particles measured by atomic force microscopy is 19 nm or less.

[0031] The inkjet composition used in this step and the recording apparatus equipped with an inkjet head for ejecting the inkjet composition will be described in detail later.

[0032] The recording medium onto which the inkjet composition is applied may be of any type, and may be either absorbent or non-absorbent, and may include, for example, paper such as plain paper or paper specifically for inkjet printing, plastic materials, metals, ceramics, wood, shells, natural fibers or synthetic fibers such as cotton, polyester, or wool, nonwoven fabrics, etc. The shape of the recording medium is not particularly limited, and may be any type, such as a sheet.

[0033] The application pattern of the inkjet composition onto the recording medium, the amount applied per unit area onto the recording medium, and the like are adjusted appropriately depending on the recorded matter to be produced, and are not particularly limited.

[0034] [1-2] Circulation process The inkjet head that ejects the inkjet composition is provided with a circulation flow path that circulates the inkjet composition, and the recording method of the present invention includes a circulation step of circulating the inkjet composition through the inkjet head. This allows the effects of the present invention to be achieved as described above.

[0035] The circulation step may be performed simultaneously with the ejection step, or may be performed at a timing when the ejection step is not being performed. For example, the circulation step may be performed only at a timing when the ejection step is not being performed, such as when the ejection step is paused or when the recording apparatus is idling, but it is preferable that at least a part of the circulation step is performed simultaneously with the ejection step. This makes the above-mentioned effects more pronounced.

[0036] The lower limit of the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow channel to the maximum ejection rate of the inkjet head is preferably 0.50, more preferably 0.60, even more preferably 0.70, and most preferably 0.75. The upper limit of the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow channel to the maximum ejection rate of the inkjet head is preferably 15, more preferably 10, even more preferably 5.0, and most preferably 3.0.

[0037] This makes it possible to prevent the circulation flow rate of the inkjet composition flowing through the circulation flow path from becoming greater than necessary, while also making it possible to more significantly exhibit the above-mentioned effects.

[0038] The maximum ejection amount of the inkjet composition refers to the maximum ejection amount of droplets of the inkjet composition per ejection performed in recording, and the ejection amount of the inkjet composition ejected from the inkjet head when the inkjet composition is ejected from all nozzles used for recording of the inkjet head at the maximum ejection frequency of the inkjet composition performed in recording.

[0039] The circulation flow rate of the inkjet composition flowing through the circulation flow path is the sum of the flow rates of the inkjet composition flowing through each discharge path provided in the inkjet head for the inkjet composition and connected to the nozzles of the inkjet head.

[0040] The maximum ejection amount of the ink jet composition and the flow rate of the ink jet composition flowing through the circulation flow path can be expressed as a mass per unit time.

[0041] [1-3] Dispersion medium removal process A dispersion medium removing step may be carried out to remove the dispersion medium that functions to disperse the metal pigment in the inkjet composition from the inkjet composition that has been applied to the recording medium.

[0042] This step can be carried out by, for example, subjecting the recording medium to which the inkjet composition has been applied to a heat treatment, placing the recording medium to which the inkjet composition has been applied in a reduced pressure atmosphere, or by a combination of these methods. This step may also be carried out by natural drying.

[0043] In addition, when the dispersion medium constituting the inkjet composition is highly volatile, the dispersion medium can be substantially removed without providing this step. More specifically, since the dispersion medium volatilizes before or in a relatively short time after the droplets of the inkjet composition land on the recording medium, there is no need to provide a separate dispersion medium removal step.

[0044] When this step is carried out by heat treatment, the heating temperature in this step varies depending on the composition of the dispersion medium and is not particularly limited, but the lower limit of the heating temperature in this step is preferably 30°C, more preferably 40°C, and even more preferably 50°C. Furthermore, when this step is carried out by heat treatment, the upper limit of the heating temperature in this step is preferably 100°C, more preferably 90°C, and even more preferably 80°C.

[0045] This effectively prevents the dispersion medium from unintentionally remaining in the final recorded product and from adversely affecting the recording medium, etc., thereby improving the reliability of the recorded product and further improving the productivity of the recorded product, which is also advantageous from the viewpoint of energy conservation.

[0046] When this step is carried out by heat treatment, the heating time in this step varies depending on the composition of the dispersion medium, the heating temperature, etc., and is not particularly limited, but the lower limit of the heating time in this step is preferably 10 minutes, more preferably 20 minutes, and even more preferably 30 minutes. Also, when this step is carried out by heat treatment, the upper limit of the heating time in this step is preferably 60 minutes, more preferably 50 minutes, and even more preferably 40 minutes.

[0047] This effectively prevents the dispersion medium from unintentionally remaining in the final recorded product and from adversely affecting the recording medium, etc., thereby improving the reliability of the recorded product and further improving the productivity of the recorded product, which is also advantageous from the viewpoint of energy conservation.

[0048] When this step is carried out by heat treatment, the heating method is not particularly limited, but examples thereof include a heat press method, an atmospheric pressure steam method, a high pressure steam method, and a Thermofix method.

[0049] The heat source for heating is not particularly limited, but for example, an infrared lamp or the like can be used.

[0050] [1-4] Other processes The recording method of the present invention may include steps other than those described above.

[0051] For example, when the composition for inkjet contains a curable resin as a binder, the composition may have a curing step of curing the curable resin.

[0052] The curing step can be carried out by a method selected according to the type of the curable resin. For example, in the case of a thermosetting resin, this step can be carried out by a heat treatment. In addition, in the case of a photocurable resin, this step can be carried out by a light irradiation treatment.

[0053] [1-5] Inkjet composition Next, the inkjet composition to be applied to the recording method of the present invention will be described in detail.

[0054] [1-5-1] Metallic pigments The inkjet composition according to the present invention contains a metal pigment consisting of a plurality of metal particles.

[0055] Metal particles are particles in which at least a portion of the visible portion is made of a metal material, and usually the vicinity of the outer surface is made of a metal material.

[0056] Metal particles are a component that has a significant effect on the appearance of a recorded matter produced using the recording method and recording apparatus of the present invention.

[0057] The metal particles may be any metal particles as long as at least a region including the surface is made of a metal material. For example, the entire metal particle may be made of a metal material, or the metal particle may have a base made of a non-metallic material and a coating made of a metal material that covers the base. Furthermore, the metal particles may have an oxide coating, such as a passive film, formed on their surfaces. Even with such metal particles, the problems described above have occurred in the past, and by applying the present invention, the excellent effects described above can be obtained.

[0058] The metal material constituting the metal particles can be a simple metal or various alloys, etc. Examples include aluminum, silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, iron, copper, etc. Of these, the metal particles are preferably made of a material containing aluminum or an aluminum alloy.

[0059] This makes it possible to more effectively prevent undesired settling or aggregation of metal particles that satisfy the above conditions in an inkjet head, thereby improving the ejection stability of the inkjet composition, and also to improve the glossiness and luxurious feel of the recorded matter while suppressing an increase in the production cost of the recorded matter.

[0060] In the present invention, the metal particles are scaly. This allows the metal particles to be arranged on the recording medium to which the inkjet composition is applied, with their main surfaces conforming to the surface shape of the recording medium, thereby more effectively exhibiting the inherent glossiness and high-quality feel of the metal material that constitutes the metal particles in the resulting recorded matter, thereby providing the printed portion with particularly excellent glossiness and a luxurious feel, as well as particularly excellent abrasion resistance of the recorded matter.

[0061] 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 from a predetermined angle, for example, when viewed in a plan view, is larger than the area when viewed from an angle perpendicular to the viewing direction. In particular, when viewed from a direction in which the projected area is largest, i.e., the area S1 [μm 2 ] and the area S0 [μm 2 The ratio S1 / S0 to the particle diameter [μm] is preferably 2 or more, more preferably 5 or more, and even more preferably 8 or more. For example, 50 random particles are observed, and the average value calculated for these particles can be used as this value. Observation can be carried out using, for example, an electron microscope, an atomic force microscope, or the like.

[0062] The average thickness of the metal particles measured by atomic force microscopy may be 19 nm or less, preferably 17 nm or less, and more preferably 15 nm or less, and the lower limit of the average thickness of the metal particles measured by atomic force microscopy is preferably 5 nm, more preferably 6 nm, and even more preferably 7 nm. This makes the above-mentioned effects more pronounced.

[0063] The lower limit of the volume average particle diameter D50 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 D50 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.

[0064] This improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0065] In this specification, the volume-average particle size 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.

[0066] The lower limit of the average aspect ratio of metal particles, which is the ratio of the volume average particle diameter D50 of metal particles to the average thickness of metal particles determined by atomic force microscopy, is preferably 10, more preferably 20, even more preferably 22, and most preferably 24. The upper limit of the average aspect ratio of metal particles, which is the ratio of the volume average particle diameter D50 of metal particles to the average thickness of metal particles determined by atomic force microscopy, is preferably 2000, more preferably 200, and even more preferably 50.

[0067] This improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0068] The average aspect ratio of the metal particles can be determined by measuring a dispersion of the metal particles using a laser diffraction / scattering method.

[0069] The lower limit of the content of metal particles in the composition for inkjet is not particularly limited, but is preferably 0.2 mass%, more preferably 0.3 mass%, and even more preferably 0.4 mass%, and the upper limit of the content of metal particles in the composition for inkjet is not particularly limited, but is preferably 4.0 mass%, more preferably 3.5 mass%, and even more preferably 3.0 mass%.

[0070] This improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0071] The metal particles may be produced by any method. However, if the metal particles are made of Al, they are preferably obtained by forming an Al film by vapor deposition and then pulverizing the film. This allows the inherent glossiness of Al to be more effectively expressed in the printed portion formed using the recording method and recording apparatus of the present invention. Furthermore, the variation in properties between particles can be suppressed. Furthermore, by using this method, even relatively thin metal particles can be suitably produced.

[0072] When producing metal particles using such a method, the metal particles can be suitably produced, for example, by forming a film composed of Al on a substrate. 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.

[0073] Preferably, the pulverization is carried out by applying ultrasonic vibrations to the film in a liquid, which allows metal particles having a particle size as described below to be easily and reliably obtained, and also prevents variations in size, shape, and properties among the individual metal particles.

[0074] Furthermore, when milling is performed by the above-described method, the liquid that can be suitably used includes alcohols, hydrocarbon compounds, ether compounds, and polar compounds such as propylene carbonate, γ-butyrolactone, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, cyclohexanone, acetonitrile, etc. Use of such a liquid can prevent undesired oxidation of the metal particles, while achieving particularly high productivity of the metal particles and particularly small variations in size, shape, and properties among the individual particles.

[0075] 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, 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.

[0076] [1-5-2]Dispersion medium The inkjet composition according to the present invention contains a dispersion medium that has the function of dispersing the metal pigment.

[0077] When the ink-jet composition contains a dispersion medium, the ink-jet composition can be ejected by inkjet.

[0078] The dispersion medium is not particularly limited as long as it is a liquid capable of dispersing the metal pigment, but it is preferably composed mainly of a liquid component other than water, particularly an organic solvent. In other words, the inkjet composition is preferably a solvent-based ink. An ink whose solvent component is mainly composed of an organic solvent is called a solvent-based ink.

[0079] This improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0080] As described above, the inkjet composition is preferably a solvent-based ink, but even in such a case, it may contain a small amount of water. However, when the inkjet composition is a solvent-based ink, the content of water in the inkjet composition is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less.

[0081] As the organic solvent used as the dispersion medium, for example, an ester compound, an ether compound, a hydroxyketone, a carbonic acid diester, a cyclic amide compound, or the like can be used. More specifically, examples of compounds that can be used as dispersion media include 2-(2-methoxy-1-methylethoxy)-1-methylethyl acetate, triethylene glycol dimethyl ether, triethylene glycol diacetate, diethylene glycol monoethyl ether acetate, 4-methyl-1,3-dioxolan-2-one, bis(2-butoxyethyl) ether, dimethyl glutarate, ethylene glycol di-n-butylate, 1,3-butylene glycol diacetate, diethylene glycol monobutyl ether acetate, tetraethylene glycol dimethyl ether, 1,6-diacetoxyhexane, tripropylene glycol monomethyl ether, butoxypropanol, diethylene glycol methyl ethyl ether, diethylene glycol methyl butyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl butyl ether, dipropylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, and 3-ethoxyethyl propionate. , diethylene glycol ethyl methyl ether, 3-methoxybutyl acetate, diethylene glycol diethyl ether, ethyl octanoate, ethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether, cyclohexyl acetate, diethyl succinate, ethylene glycol diacetate, propylene glycol diacetate, 4-hydroxy-4-methyl-2-pentanone, dimethyl succinate, 1-butoxy-2-propanol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, 3-methoxy-n-butyl acetate, diacetin, dipropylene glycol mono n-propyl ether, polyethylene glycol monomethyl ether, butyl glycolate, ethylene glycol monohexyl ether, dipropylene glycol mono n-butyl ether, N-methyl-2-pyrrolidone, triethylene glycol butyl methyl ether, bis(2-propoxyethyl) ether, diethylene glycol diacetate,Examples of the alkyl ethers include diethylene glycol butyl methyl ether, diethylene glycol butyl ethyl ether, diethylene glycol butyl propyl ether, diethylene glycol ethyl propyl ether, diethylene glycol methyl propyl ether, diethylene glycol propyl ether acetate, triethylene glycol methyl ether acetate, triethylene glycol ethyl ether acetate, triethylene glycol propyl ether acetate, triethylene glycol butyl ether acetate, triethylene glycol butyl ethyl ether, triethylene glycol ethyl methyl ether, triethylene glycol ethyl propyl ether, triethylene glycol methyl propyl ether, dipropylene glycol methyl ether acetate, n-nonyl alcohol, diethylene glycol mono-normal butyl ether, triethylene glycol monomethyl ether, ethylene glycol 2-ethylhexyl ether, triethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monobutyl ether, diethylene glycol mono-2-ethylhexyl ether, tripropylene glycol mono-n-butyl ether, butyl cellosolve acetate, and γ-butyrolactone, and these may be used alone or in combination of two or more.

[0082] Among the organic solvents mentioned above, glycol ethers are preferred. Glycol ethers are etherified glycol compounds. Examples of glycol ethers include monoethers and diethers, with diethers being more preferred. The glycol moiety of glycol ethers includes glycols and glycols obtained by intermolecular condensation of glycols between hydroxyl groups. The ether moiety of glycol ethers includes alkyl ethers, etc.

[0083] Among these, the dispersion medium preferably contains at least one of diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, and triethylene glycol monobutyl ether, and more preferably contains at least one of diethylene glycol diethyl ether and diethylene glycol methyl ethyl ether.

[0084] This further improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and also improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0085] The sum of the contents of diethylene glycol diethyl ether and diethylene glycol methyl ethyl ether in the entire dispersion medium constituting the composition for inkjet is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. There is no particular upper limit, but it is preferably 99% by mass or less, more preferably 95% by mass or less. This makes the above-mentioned effects more pronounced.

[0086] The lower limit of the content of the dispersion medium (organic solvent) in the composition for inkjet is not particularly limited, but is preferably 70.0 mass %, more preferably 80.0 mass %, and even more preferably 85.0 mass %. The upper limit of the content of the dispersion medium in the composition for inkjet is not particularly limited, but is preferably 99.8 mass %, more preferably 99.5 mass %, and even more preferably 99.0 mass %.

[0087] This further improves the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and also improves the glossiness of recorded matter produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0088] [1-5-3] Surface treatment agents The metal particles contained in the inkjet composition are preferably surface-modified with a surface treatment agent.

[0089] This improves the dispersion stability of the inkjet composition of metal particles, thereby improving the storage stability of the inkjet composition and the ejection stability when using an inkjet method, thereby improving the glossiness of recorded materials produced using the inkjet composition and more effectively preventing the occurrence of undesired color unevenness, etc.

[0090] In particular, it is preferable that the metal particles are surface-treated with a phosphorus compound or a silicon compound.

[0091] This further improves the dispersion stability of the inkjet composition for metal particles, further improving the storage stability of the inkjet composition and the ejection stability when using an inkjet method, and also improving the glossiness of recorded materials produced using the inkjet composition, while more effectively preventing the occurrence of undesired color unevenness, etc.

[0092] The phosphorus compound functioning as a surface treatment agent is not particularly limited as long as it contains a phosphorus atom in its molecule and has the function of modifying the surface of metal particles, i.e., is a phosphorus-based surface treatment agent. However, it is preferably a hydrophobic phosphorus-based surface treatment agent that, when attached to metal particles, has the function of increasing the hydrophobicity of metal particles compared to metal particles to which the phosphorus compound is not attached. This makes the above-mentioned effects more pronounced.

[0093] Examples of hydrophobic phosphorus-based surface treatment agents that can be used include phosphoric acid derivatives, phosphonic acid derivatives, phosphinic acid derivatives, etc. Examples of derivatives include tautomers, esterified products, etherified products, and products in which hydrogen atoms in the structural formula are replaced with organic substituents.

[0094] These hydrophobic phosphorus-based surface treatment agents may also be used as surfactants, etc. The hydrophobic phosphorus-based surface treatment agent preferably has a hydrophobic atom or atomic group.

[0095] Examples of hydrophobic atoms or atomic groups include fluorine atoms, alkyl groups having 3 or more carbon atoms, and alkyl groups in which at least a portion of the hydrogen atoms are substituted with fluorine atoms. The number of carbon atoms in the alkyl group or the alkyl group in which at least a portion of the hydrogen atoms are substituted with fluorine atoms is preferably 3 or more, more preferably 5 or more, and even more preferably 8 or more. It is further preferably 10 or more, and even more preferably 15 or more. The upper limit of the carbon number is not particularly limited, but is preferably 30, more preferably 25, and even more preferably 20. The alkyl group or the alkyl group in which at least a portion of the hydrogen atoms are substituted with fluorine atoms is preferably bonded to the phosphorus atom of a phosphorus-based surface treatment agent, or a hydroxyl group bonded to the phosphorus atom of a phosphorus-based surface treatment agent that has been etherified with the alkyl group or the alkyl group.

[0096] As the hydrophobic phosphorus-based surface treatment agent, a fluorine-based phosphorus-based compound, which is a phosphorus compound having at least one fluorine atom in the molecule, can be suitably used.

[0097] This makes it possible to further increase the hydrophobicity of the metal particles in a state where they are attached, thereby improving the dispersion stability of the metal particles in the inkjet composition and the ejection stability by the inkjet method. Furthermore, in a recorded matter produced using the recording method and recording apparatus of the present invention, the metal particles can be more suitably arranged near the outer surface of the printed part, and the inherent properties of the metal material that constitutes the metal particles, such as glossiness, can be more effectively exhibited.

[0098] When the hydrophobic phosphorus-based surface treatment agent is a fluorine-based phosphorus-based compound, the fluorine-based phosphorus-based compound preferably has a perfluoroalkyl structure.

[0099] This further improves the storage stability of the inkjet composition and the ejection stability by the inkjet method, and further improves the glossiness and abrasion resistance of the printed portion of a recording material produced using the inkjet composition.

[0100] The silicon compound that functions as a surface treatment agent is not particularly limited as long as it contains a silicon atom in its molecule and has the function of modifying the surface of metal particles, i.e., is a silicon-based surface treatment agent. For example, a silane coupling agent or a surface treatment agent prepared by using tetraethoxysilane and aqueous ammonia can be used.

[0101] The inkjet composition according to the present invention may contain multiple types of compounds as surface treatment agents. In such a case, the same metal particles may be surface-treated with multiple types of surface treatment agents. Furthermore, the inkjet composition may contain metal particles that have been surface-treated with different surface treatment agents.

[0102] The surface treatment of metal particles with a surface treatment agent may be carried out, for example, by including the 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.

[0103] When the same particles are surface-treated with multiple types of surface treatment agents, the surface treatment may be performed in multiple steps corresponding to the respective surface treatment agents, or the surface treatment may be performed with the multiple types of surface treatment agents in the same step.

[0104] The lower limit of the content of the surface treatment agent in the composition for inkjet is not particularly limited, but is preferably 0.01% by mass, more preferably 0.05% by mass, and even more preferably 0.10% by mass. The upper limit of the content of the surface treatment agent in the composition for inkjet is not particularly limited, but is preferably 1.5% by mass, more preferably 1.0% by mass, and even more preferably 0.8% by mass.

[0105] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0106] The lower limit of the content of the surface treatment agent in the composition for inkjet is preferably 5.0 parts by mass, more preferably 10 parts by mass, and even more preferably 20 parts by mass, relative to 100 parts by mass of the metal particles, and the upper limit of the content of the surface treatment agent in the composition for inkjet is preferably 60 parts by mass, more preferably 50 parts by mass, and even more preferably 40 parts by mass, relative to 100 parts by mass of the metal particles.

[0107] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0108] [1-5-4] Polyoxyalkyleneamine compounds The composition for inkjet according to the present invention may contain a polyoxyalkyleneamine compound.

[0109] This improves the dispersion stability of the inkjet composition of metal particles, thereby improving the storage stability of the inkjet composition and the ejection stability when using an inkjet method, thereby improving the glossiness of recorded materials produced using the inkjet composition and more effectively preventing the occurrence of undesired color unevenness, etc.

[0110] In particular, when the metal particles have been surface-treated with the above-mentioned surface treatment agent, a synergistic effect is exhibited by using these in combination, and the above-mentioned effects are exhibited more significantly.

[0111] The polyoxyalkyleneamine compound may be any amine compound having a polyoxyalkylene structure in the molecule, but is preferably at least one of the compounds represented by the following formula (1) and salts thereof: R 1 -(OR 2 ) x -NH2 (1) (In formula (1), R 1 is a hydrogen atom or an alkyl group having 4 or less carbon atoms, and R 2 is an alkylene group having 5 or less carbon atoms, and x is an integer of 10 or more. 2 It may have multiple types of oxyalkylene units with different conditions.)

[0112] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0113] As described above, the polyoxyalkyleneamine compound is preferably at least one of the compounds represented by the above formula (1) and salts thereof, and more preferably at least one of the compounds represented by the following formula (2) and salts thereof:

[0114] [ka] (In formula (2), R 1 is a hydrogen atom or an alkyl group having 4 or less carbon atoms, and R 2 is a hydrogen atom or an alkyl group having 3 or less carbon atoms, and x is an integer of 10 or more. In addition, in formula (2), multiple types of oxyalkylene units having different conditions for R may be provided.

[0115] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0116] R in the above formula (1) and formula (2) 1 may be a hydrogen atom or an alkyl group having 4 or less carbon atoms, but is preferably a methyl group.

[0117] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0118] R in the above formula (2) 2 is a hydrogen atom or an alkyl group having 3 or less carbon atoms, preferably a hydrogen atom or a methyl group, and more preferably a compound represented by the following formula (3):

[0119] [ka] (In formula (3), x1 and x2 are independently an integer of 1 or more, and x1+x2 is an integer of 10 or more. In formula (3), the order of the oxyethylene unit and the oxypropylene unit does not matter.)

[0120] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0121] The lower limit of the value of x1 / x2, which is the ratio of x1 to x2 in the above formula (3), i.e., the ratio of the amount of oxyethylene units to the amount of oxypropylene units in the molecule of the polyoxyalkyleneamine compound, is preferably 0.05, more preferably 0.15, and even more preferably 0.70.The upper limit of the value of x1 / x2 is preferably 10.00, more preferably 8.00, and even more preferably 6.00.

[0122] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0123] As mentioned above, the order of the oxyethylene units and the oxypropylene units in the formula (3) does not matter. More specifically, in the formula (3), an amino group is bonded to the end of successive oxyethylene units, and a methyl group is bonded to the end of successive oxypropylene units. However, an amino group may be bonded to the end of successive oxypropylene units, and a methyl group may be bonded to the end of successive oxyethylene units. In addition, the compound represented by the formula (3) may be a block copolymer or a random copolymer.

[0124] The lower limit of the weight-average molecular weight of the polyoxyalkyleneamine compound is not particularly limited, but is preferably 400, more preferably 500, even more preferably 800, and most preferably 1000. The upper limit of the weight-average molecular weight of the polyoxyalkyleneamine compound is not particularly limited, but is preferably 8000, more preferably 5000, and even more preferably 3000.

[0125] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0126] The composition for inkjet according to the present invention may contain a plurality of types of compounds as the polyoxyalkyleneamine compound.

[0127] The lower limit of the content of the polyoxyalkyleneamine compound in the composition for inkjet is not particularly limited, but is preferably 0.01% by mass, more preferably 0.02% by mass, and even more preferably 0.03% by mass. The upper limit of the content of the polyoxyalkyleneamine compound in the composition for inkjet is not particularly limited, but is preferably 1.0% by mass, more preferably 0.80% by mass, and even more preferably 0.60% by mass.

[0128] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0129] The lower limit of the content of the polyoxyalkyleneamine compound in the composition for inkjet is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and even more preferably 1.0 part by mass, relative to 100 parts by mass of the metal particles, and the upper limit of the content of the polyoxyalkyleneamine compound in the composition for inkjet is preferably 50 parts by mass, more preferably 40 parts by mass, and even more preferably 30 parts by mass, relative to 100 parts by mass of the metal particles.

[0130] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0131] When the content of the polyoxyalkyleneamine compound in the composition for inkjet is XA [mass %] and the content of the surface treatment agent in the composition for inkjet is XP [mass %], the lower limit of the value of XA / XP is preferably 0.02, more preferably 0.05, and even more preferably 0.07. The upper limit of the value of XA / XP is preferably 3.0, more preferably 2.0, and even more preferably 1.0.

[0132] This makes it possible to further improve the storage stability of the inkjet composition, the ejection stability by the inkjet method, etc., and to further improve the glossiness of recorded matter produced using the recording method and recording apparatus of the present invention.

[0133] The treatment of metal particles with a polyoxyalkyleneamine compound may be carried out in the same step as or a different step from the surface treatment with a surface treatment agent. The treatment with a polyoxyalkyleneamine compound may be carried out before or after the surface treatment with a surface treatment agent.

[0134] [1-5-5] Other ingredients The composition for inkjet according to the present invention may contain components other than those described above, such as a leveling agent, a binder, a polymerization accelerator, a polymerization inhibitor, a photopolymerization initiator, a dispersant, a surfactant, a penetration accelerator, a moisturizer, a colorant, a fixing agent, an antifungal agent, a preservative, an antioxidant, a chelating agent, a thickener, and a sensitizer.

[0135] The binder may be any resin, and preferred examples include acrylic resins, ester resins, urethane resins, etc., with acrylic resins being more preferred. When a binder is included, it is preferably contained in an amount of 0.1% by mass or more, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less in the composition.

[0136] Preferred surfactants include silicone surfactants, fluorine surfactants, acetylene glycol surfactants, etc., and silicone surfactants are particularly preferred. When a surfactant is contained, it is preferably contained in an amount of 0.1% by mass or more, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less in the composition.

[0137] [1-5-6]Other The upper limit of the viscosity of the composition for inkjet according to the present invention at 25°C measured using a vibration 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 composition for inkjet according to the present invention at 25°C measured using a vibration viscometer in accordance with JIS Z8809 is not particularly limited, but is preferably 3 mPa·s.

[0138] This allows, for example, the composition for inkjet according to the present invention to be more suitably ejected as droplets by an inkjet method.

[0139] [2] Recording device Next, the recording apparatus of the present invention will be described.

[0140] The recording apparatus of the present invention includes an inkjet head having a circulation flow path for circulating the inkjet composition, and performs the above-described recording method of the present invention.

[0141] This makes it possible to provide a recording apparatus that can effectively prevent undesired settling of the metal pigment inside the inkjet head and stably produce recorded material with excellent gloss.

[0142] The recording apparatus of the present invention is equipped with an inkjet head that ejects the inkjet composition of the present invention.

[0143] As the inkjet method, a piezo method or a method in which ink is ejected by bubbles generated by heating the ink can be used, but the piezo method is preferred from the viewpoint of preventing deterioration of the inkjet composition.

[0144] Hereinafter, preferred embodiments of the recording apparatus of the present invention will be described in more detail with reference to the accompanying drawings.

[0145] FIG. 1 is a schematic cross-sectional view showing an example of a recording apparatus. FIG. 2 is a perspective view showing the configuration of the carriage and its surroundings in the recording apparatus shown in FIG. 1. FIG. 3 is a schematic cross-sectional view of an inkjet head of the recording apparatus. FIG. 4 is a schematic cross-sectional view showing an enlarged view of a portion of the inkjet head near a circulating liquid chamber. In the drawings used in the following explanation, the scale and relative dimensions of each component have been changed as appropriate to make each component recognizable.

[0146] The recording apparatus of the present embodiment has a circulation flow path for circulating the inkjet composition described above, and is equipped with an inkjet head that ejects the inkjet composition and causes it to adhere to a recording medium, and the inkjet composition is ejected from the inkjet head and adhered to the recording medium.

[0147] [2-1] Overview of the recording device 1 and 2, the recording apparatus 1 includes an inkjet head 2, an IR heater 3, a platen heater 4, a heater 5, a cooling fan 6, a preheater 7, a ventilation fan 8, a carriage 9, a platen 11, a carriage movement mechanism 13, and a transport means 14. The overall operation of the recording apparatus 1 is controlled by a control unit (not shown).

[0148] The inkjet head 2 is configured to perform recording on the recording medium M by ejecting an inkjet composition from the nozzles of the inkjet head 2 and depositing it on the recording medium M. In this example, the inkjet head 2 is a serial inkjet head that scans multiple times in the main scanning direction relative to the recording medium M to deposit the inkjet composition on the recording medium M. The inkjet head 2 is mounted on a carriage 9 shown in FIG. 2. The inkjet 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 13 that moves the carriage 9 in the medium width direction of the recording medium M. The medium width direction is the main scanning direction of the inkjet head 2. Scanning in the main scanning direction is also called main scanning.

[0149] Here, the main scanning direction is the direction in which the carriage 9 carrying the inkjet head 2 moves. In FIG. 2, the width direction of the recording medium M, i.e., the direction indicated by arrows S1 and S2, is the main scanning direction MS, and the direction indicated by arrows T1 and T2 is the sub-scanning direction SS. Note that a single scan involves scanning in either the main scanning direction, i.e., the direction indicated by arrow S1 or S2. Recording is performed on the recording medium M by repeatedly performing the main scan of the inkjet head 2 and the sub-scan, which is the transport of the recording medium M, multiple times. In other words, the ejection process is performed by multiple main scans in which the inkjet head 2 moves in the main scanning direction, and multiple sub-scans in which the recording medium M moves in a sub-scanning direction that intersects the main scanning direction.

[0150] The cartridge 12 that supplies the inkjet composition to the inkjet head 2 includes a plurality of independent cartridges. The cartridges 12 are detachably mounted on a carriage 9 that mounts the inkjet head 2. Each of the plurality of cartridges is filled with a different type of inkjet composition, and the inkjet composition is supplied from the cartridge 12 to each nozzle. Note that, while an example in which the cartridge 12 is mounted on the carriage 9 is shown, the present invention is not limited to this, and the cartridge 12 may be provided in a location other than the carriage 9, and the ink may be supplied to each nozzle by a supply pipe (not shown).

[0151] A conventionally known method can be used for ejection from the inkjet head 2. Here, a method of ejecting droplets by utilizing the vibration of a piezoelectric element, that is, an ejection method of forming droplets of the inkjet composition by mechanical deformation of an electrostrictive element, is used.

[0152] The recording apparatus 1 can be equipped with a dispersion medium removing means for removing the dispersion medium contained in the inkjet composition when the inkjet composition is discharged from the inkjet head 2 and deposited on the recording medium. In the illustrated configuration, the dispersion medium removing means includes an IR heater 3 and a platen heater 4. When performing the dispersion medium removing step, the IR heater 3, a ventilation fan 8, and the like can be used.

[0153] Note that, when the IR heater 3 is used, the recording medium M can be radiatively heated by radiating infrared rays from the inkjet head 2 side. This makes it easier for the inkjet head 2 to heat, but compared to heating from the back side of the recording medium M using a platen heater 4 or the like, the temperature can be increased without being affected by the thickness of the recording medium M. In addition, various fans may be provided to blow warm air or air at the same temperature as the environment onto the recording medium M to dry the inkjet composition on the recording medium M.

[0154] The platen heater 4 is capable of heating the recording medium M via the platen 11 at a position opposite the inkjet head 2 so that the inkjet composition ejected by the inkjet head 2 can be dried quickly from the moment it is deposited on the recording medium M. The platen heater 4 is capable of conductively heating the recording medium M, and is used as needed in the inkjet recording method. However, if treatment using a dispersion medium removal means is not performed, the dispersion medium removal means may not be provided.

[0155] After the ejection step, a post-heating step may be carried out in which the recording medium is heated to dry and fix the inkjet composition. The post-heating step is also called secondary heating.

[0156] The heater 5 used in the post-heating step dries and solidifies the inkjet composition attached to the recording medium M, that is, it is a heater for secondary heating or secondary drying. The heater 5 can be used in the post-heating step. By using the heater 5 to heat the recording medium M on which an image has been recorded, the dispersion medium contained in the inkjet composition evaporates and dissipates more quickly.

[0157] The recording apparatus 1 may have a cooling fan 6. After the inkjet composition recorded on the recording medium M has dried, the cooling fan 6 can cool the recording medium M to which the inkjet composition has been applied.

[0158] The recording apparatus 1 may also include a preheater 7 that preheats the recording medium M before the inkjet composition is applied to the recording medium M. Furthermore, the recording apparatus 1 may also include a ventilation fan 8 so that the inkjet composition applied to the recording medium M can be dried more efficiently.

[0159] Below the carriage 9, there are provided a platen 11 that supports the recording medium M, a carriage movement mechanism 13 that moves the carriage 9 relative to the recording medium M, and a conveying means 14 that is a roller that conveys the recording medium M in the sub-scanning direction. The operations of the carriage movement mechanism 13 and the conveying means 14 are controlled by a control unit (not shown).

[0160] [2-2] Inkjet head with circulation channel The recording apparatus of this embodiment ejects ink using an inkjet head having a circulation flow path for at least the inkjet composition. That is, at least the inkjet composition is circulated by the circulation flow path. The circulation flow path has a path for passing the inkjet composition through a pressure chamber and allowing it to flow back into the pressure chamber.

[0161] In this embodiment, the inkjet head 2 has a circulation flow path for circulating the inkjet composition.

[0162] Figure 3 is a schematic cross-sectional view of an inkjet head of a recording device. More specifically, the transport direction of the recording medium is defined as the Y direction, and this is a schematic cross-sectional view of the inkjet head taken along a line perpendicular to this. In Figure 3, a plane parallel to the surface of the recording medium M is defined as the XY plane, and the direction perpendicular to the XY plane will be referred to as the Z direction below. The direction in which the inkjet composition is ejected from the inkjet head 2 corresponds to the Z direction.

[0163] The multiple nozzles N of the inkjet head 2 are arranged in the Y direction to form a nozzle row. In the inkjet head 2, a central plane O that passes through a central axis parallel to the Y direction and is parallel to the Z direction, i.e., the YZ plane, will be referred to as the "central plane" in the following explanation.

[0164] 3, the inkjet head 2 has a structure in which elements related to each nozzle N in the first row L1 and elements related to each nozzle N in the second row L2 are arranged symmetrically with respect to a central plane O. That is, the portion of the inkjet head 2 on the positive side in the X direction, i.e., the first portion P1, and the portion on the negative side in the X direction, i.e., the second portion P2, across the central plane O, have a substantially common structure. The multiple nozzles N in the first row L1 are formed in the first portion P1, and the multiple nozzles N in the second row L2 are formed in the second portion P2. The central plane O corresponds to the boundary surface between the first portion P1 and the second portion P2.

[0165] 3, the nozzles N in the second row L2 and the nozzles N in the first row L1 constitute a nozzle row filled with the inkjet composition. Although the region of the inkjet head from which the inkjet composition is ejected is not described here, it may be configured in the same way.

[0166] As shown in FIG. 3, the inkjet head 2 includes a flow path forming section 30. The flow path forming section 30 is a structure that forms a flow path for supplying an inkjet composition to a plurality of nozzles N. In this embodiment, the flow path forming section 30 is configured by laminating a first flow path substrate 32 and a second flow path substrate 34. Each of the first flow path substrate 32 and the second flow path substrate 34 is a plate-like member that is long in the Y direction. The second flow path substrate 34 is attached to the surface Fa of the first flow path substrate 32 on the negative side in the Z direction, for example, by using an adhesive.

[0167] As shown in FIG. 3 , in addition to the second flow path substrate 34, the vibrating section 42, the piezoelectric element 44, the protective member 46, and the housing section 48 are disposed on the surface Fa of the first flow path substrate 32. On the other hand, a nozzle plate 52 and a vibration absorber 54 are disposed on the positive side of the first flow path substrate 32 in the Z direction, i.e., on the surface Fb opposite to the surface Fa. The elements of the inkjet head 2 are generally plate-like members that are elongated in the Y direction, similar to the first flow path substrate 32 and the second flow path substrate 34, and are bonded to each other using, for example, an adhesive. The direction in which the first flow path substrate 32 and the second flow path substrate 34 are stacked, the direction in which the first flow path substrate 32 and the nozzle plate 52 are stacked, or the direction perpendicular to the surface of each plate-like element can also be understood as the Z direction.

[0168] The nozzle plate 52 is a plate-like member on which a plurality of nozzles N are formed. The nozzle plate 52 is attached to the surface Fb of the first flow path substrate 32 using, for example, an adhesive. Each of the plurality of nozzles N is a circular through-hole through which the inkjet composition passes. The nozzle plate 52 is formed with a plurality of nozzles N constituting a first row L1 and a plurality of nozzles N constituting a second row L2. Specifically, the plurality of nozzles N of the first row L1 are formed along the Y direction in a region of the nozzle plate 52 on the positive side in the X direction as viewed from the center plane O, and the plurality of nozzles N of the second row L2 are formed along the Y direction in a region on the negative side in the X direction. The nozzle plate 52 is a single plate-like member that is continuous across the portion where the plurality of nozzles N of the first row L1 are formed and the portion where the plurality of nozzles N of the second row L2 are formed. The nozzle plate 52 is manufactured by processing a single-crystal silicon substrate using semiconductor manufacturing techniques, such as dry etching and wet etching. However, known materials and manufacturing methods may be used to manufacture the nozzle plate 52.

[0169] As shown in the figure, the first flow path substrate 32 has a space Ra, multiple supply channels 61, and multiple communication channels 63 formed in each of the first portion P1 and the second portion P2. The space Ra is an elongated opening extending along the Y direction when viewed from the Z direction in a plan view, and the supply channels 61 and communication channels 63 are through-holes formed for each nozzle N. The multiple communication channels 63 are arranged in the Y direction in a plan view, and the multiple supply channels 61 are arranged in the Y direction between the arrangement of the multiple communication channels 63 and the space Ra. The multiple supply channels 61 are commonly connected to the space Ra. Furthermore, any one communication channel 63 overlaps with the nozzle N corresponding to that communication channel 63 in a plan view. Specifically, any one communication channel 63 in the first portion P1 is connected to one nozzle N in the first row L1 that corresponds to that communication channel 63. Similarly, any one of the communication passages 63 in the second portion P2 communicates with one nozzle N corresponding to that communication passage 63 in the second row L2.

[0170] As shown in the figure, the second flow path substrate 34 is a plate-like member in which multiple pressure chambers C are formed for each of the first portion P1 and the second portion P2. The multiple pressure chambers C are arranged in the Y direction. Each pressure chamber C is formed for each nozzle N and is an elongated space extending along the X direction in a plan view. Like the nozzle plate 52 described above, the first flow path substrate 32 and the second flow path substrate 34 are manufactured by processing a single-crystal silicon substrate using, for example, semiconductor manufacturing technology. However, any known material or manufacturing method may be used to manufacture the first flow path substrate 32 and the second flow path substrate 34. As illustrated above, the flow path forming portion 30 and the nozzle plate 52 include substrates made of silicon. Therefore, using semiconductor manufacturing technology, for example, as in the above example, has the advantage of enabling fine flow paths to be formed with high precision in the flow path forming portion 30 and the nozzle plate 52.

[0171] As shown in the figure, a vibrating section 42 is provided on the surface of the second flow path substrate 34 opposite to the first flow path substrate 32. The vibrating section 42 is a plate-like member that can vibrate elastically. Note that it is also possible to form the second flow path substrate 34 and the vibrating section 42 integrally by selectively removing a portion in the plate thickness direction from a region of a plate-like member of a predetermined thickness that corresponds to the pressure chamber C.

[0172] As shown in the figure, the surface Fa of the first flow path substrate 32 and the vibration section 42 face each other with a gap between them inside each pressure chamber C. The pressure chamber C is a space located between the surface Fa of the first flow path substrate 32 and the vibration section 42, and generates a pressure change in the inkjet composition filled in that space. Each pressure chamber C is a space with the X direction as its longitudinal direction, for example, and is individually formed for each nozzle N. A plurality of pressure chambers C are arranged in the Y direction in each of the first row L1 and the second row L2.

[0173] As shown in the figure, the end of any one pressure chamber C on the central plane O side overlaps with the communicating passage 63 in a plan view, and the end on the opposite side of the central plane O overlaps with the supply passage 61 in a plan view. Therefore, in each of the first portion P1 and the second portion P2, the pressure chamber C communicates with the nozzle N via the communicating passage 63 and with the space Ra via the supply passage 61. It is also possible to add a predetermined flow path resistance by forming a throttle flow path in the pressure chamber C, where the flow path width is narrowed.

[0174] As shown in the figure, a plurality of piezoelectric elements 44 corresponding to different nozzles N are provided in each of the first portion P1 and the second portion P2 on the surface of the vibration portion 42 opposite the pressure chamber C. The piezoelectric elements 44 are elements that deform when a drive signal is supplied. The plurality of piezoelectric elements 44 are arranged in the Y direction so as to correspond to each pressure chamber C. Any one piezoelectric element 44 is, for example, a laminate having a piezoelectric layer interposed between two opposing electrodes. Note that it is also possible to define the portion that deforms when a drive signal is supplied, i.e., the active portion that vibrates the vibration portion 42, as the piezoelectric element 44. In this embodiment, when the vibration portion 42 vibrates in conjunction with the deformation of the piezoelectric elements 44, the pressure in the pressure chamber C fluctuates, and the inkjet composition filled in the pressure chamber C is ejected through the communicating passage 63 and the nozzle N.

[0175] The protective member 46 is a plate-like member for protecting the multiple piezoelectric elements 44, and is placed on the surface of the vibration section 42 or the surface of the second flow path substrate 34. The protective member 46 may be made of any material and manufactured by any method, but similar to the first flow path substrate 32 and the second flow path substrate 34, the protective member 46 may be formed, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology. The multiple piezoelectric elements 44 arranged in the Y direction in the figure are housed in a recess formed in the surface of the protective member 46 on the vibration section 42 side.

[0176] An end of the wiring board 28 is joined to the surface of the vibration section 42 opposite to the flow path forming section 30, or to the surface of the flow path forming section 30. The wiring board 28 is a flexible mounting component on which a plurality of wires (not shown) are formed, which electrically connect the control unit and the inkjet head 2. The end of the wiring board 28 that passes through an opening formed in the protective member 46 and an opening formed in the housing section 48 and extends to the outside is connected to the control unit. For example, a flexible wiring board 28 such as a flexible printed circuit or a flexible flat cable is preferably used.

[0177] The housing 48 is a case for storing the inkjet composition to be supplied to the multiple pressure chambers C and further to the multiple nozzles N. The surface of the housing 48 on the positive side in the Z direction is bonded to the surface Fa of the first flow path substrate 32, for example, with an adhesive. Any known technology or manufacturing method can be used to manufacture the housing 48. For example, the housing 48 can be formed by injection molding of a resin material.

[0178] As shown in the figure, a space Rb is formed in each of the first portion P1 and the second portion P2 in the housing 48. The space Rb in the housing 48 and the space Ra in the first flow path substrate 32 are mutually connected. The space formed by the space Ra and the space Rb functions as a liquid storage chamber R that stores the ink jet composition to be supplied to the multiple pressure chambers C. The liquid storage chamber R is a common liquid chamber shared by the multiple nozzles N. A liquid storage chamber R is formed in each of the first portion P1 and the second portion P2. The liquid storage chamber R in the first portion P1 is located on the positive side of the X direction from the central plane O, and the liquid storage chamber R in the second portion P2 is located on the negative side of the X direction from the central plane O. An inlet 482 is formed in the surface of the housing 48 opposite to the first flow path substrate 32, for introducing the ink jet composition supplied from a liquid container into the liquid storage chamber R.

[0179] As shown in the figure, a vibration absorber 54 is provided for each of the first portion P1 and the second portion P2 on the surface Fb of the first flow path substrate 32. The vibration absorber 54 is a flexible film, i.e., a compliant substrate, that absorbs pressure fluctuations of the inkjet composition in the liquid storage chamber R. For example, the vibration absorber 54 is provided on the surface Fb of the first flow path substrate 32 so as to close the space Ra of the first flow path substrate 32 and the plurality of supply channels 61, and forms a wall surface of the liquid storage chamber R, specifically a bottom surface.

[0180] As shown in the figure, a space, i.e., a circulation liquid chamber 65, is formed on the surface Fb of the first flow path substrate 32 facing the nozzle plate 52. The circulation liquid chamber 65 for the first embodiment liquid is an elongated, bottomed hole extending in the Y direction in a plan view. The nozzle plate 52 joined to the surface Fb of the first flow path substrate 32 blocks the opening of the circulation liquid chamber 65. The circulation liquid chamber 65 is continuous across the plurality of nozzles N along the first row L1 and the second row L2, for example. Specifically, the circulation liquid chamber 65 is formed between the arrangement of the plurality of nozzles N in the first row L1 and the arrangement of the plurality of nozzles N in the second row L2. Therefore, the circulation liquid chamber 65 is located between the communication path 63 of the first portion P1 and the communication path 63 of the second portion P2. In this way, the flow path forming section 30 is a structure in which the pressure chamber C and the communication passage 63 in the first portion P1, the pressure chamber C and the communication passage 63 in the second portion P2, and the circulating fluid chamber 65 located between the communication passage 63 in the first portion P1 and the communication passage 63 in the second portion P2 are formed. The flow path forming section 30 includes a wall-like portion that separates the circulating fluid chamber 65 from each communication passage 63, i.e., a partition portion 69.

[0181] As described above, the plurality of pressure chambers C and the plurality of piezoelectric elements 44 are arranged in the Y direction in each of the first portion P1 and the second portion P2. Therefore, it is also possible to say that the circulating liquid chamber 65 extends in the Y direction so as to be continuous across the plurality of pressure chambers C or the plurality of piezoelectric elements 44 in each of the first portion P1 and the second portion P2. It is also possible that the circulating liquid chamber 65 and the liquid storage chamber R extend in the Y direction with a gap between them, and the pressure chamber C, the communication passage 63, and the nozzle N are located within that gap.

[0182] As shown in FIG. 4 , each nozzle N includes a first section n1 and a second section n2. The first section n1 and the second section n2 are cylindrical spaces that are coaxially formed and communicate with each other. The second section n2 is located on the flow path forming portion 30 side as viewed from the first section n1. In this embodiment, the central axis Qa of each nozzle N is located on the opposite side of the circulating fluid chamber 65 as viewed from the central axis Qb of the communicating passage 63. The inner diameter d2 of the second section n2 is larger than the inner diameter d1 of the first section n1. The stepped configuration of each nozzle N as described above has the advantage of making it easier to set the flow path resistance of each nozzle N to the desired characteristics. In this embodiment, the central axis Qa of each nozzle N is located on the opposite side of the circulating fluid chamber 65 as viewed from the central axis Qb of the communicating passage 63.

[0183] 4, a plurality of discharge channels 72 are formed for each of the first portion P1 and the second portion P2 on the surface of the nozzle plate 52 facing the flow path forming portion 30. The plurality of discharge channels 72 in the first portion P1 correspond one-to-one to the plurality of nozzles N in the first row L1 or the plurality of communicating channels 63 corresponding to the first row L1. Furthermore, the plurality of discharge channels 72 in the second portion P2 correspond one-to-one to the plurality of nozzles N in the second row L2 or the plurality of communicating channels 63 corresponding to the second row L2.

[0184] In an inkjet head, a flow path for supplying an inkjet composition and a flow path for discharging the inkjet composition are collectively referred to as a circulation flow path. The flow path for discharging the inkjet composition is a flow path through which the inkjet composition deviates from and exits the path through which the inkjet composition passes from the path through which the inkjet composition is supplied to the inkjet head until it is ejected from the nozzle. The flow path for supplying an inkjet composition is a flow path through which the inkjet composition that has exited the path by the flow path for discharging the inkjet composition reenters the path. The flow path for supplying an inkjet composition may constitute a part of the path. In other words, it is sufficient if the flow path supplies the inkjet composition that has exited the path back into the path.

[0185] 3, the circulation flow path is a combination of at least the supply path 61 and the discharge path 72. This is a flow path that enables the liquid supplied from the supply path 61 to be ejected from the nozzle N to be discharged from the liquid path from the supply path 61 to the nozzle N without being ejected from the nozzle N, and then to be supplied again to the liquid path from the supply path 61 to the nozzle N.

[0186] Each discharge channel 72 is a groove extending in the X direction, i.e., an elongated hole with a bottom, and functions as a flow path for circulating the inkjet composition. The discharge channel 72 is formed at a position spaced apart from the nozzle N, specifically, on the circulating liquid chamber 65 side as viewed from the nozzle N corresponding to the discharge channel 72. For example, the plurality of nozzles N, particularly the second section n2, and the plurality of discharge channels 72 are formed collectively in a common process using semiconductor manufacturing technology, for example, processing technology such as dry etching or wet etching.

[0187] As shown in FIG. 4 , each discharge channel 72 is formed linearly with a channel width equal to the inner diameter d2 of the second section n2 of the nozzle N. The width of the discharge channel 72 in the Y direction is smaller than the width of the pressure chamber C in the Y direction. Therefore, the channel resistance of the discharge channel 72 can be increased compared to a configuration in which the channel width of the discharge channel 72 is larger than the channel width of the pressure chamber C. A configuration in which the channel width is larger than the channel width of the pressure chamber C is also acceptable. Meanwhile, the depth Da of the discharge channel 72 relative to the surface of the nozzle plate 52 is constant throughout its entire length. In this example, each discharge channel 72 is formed to the same depth as the second section n2 of the nozzle N. The discharge channel 72 and the second section n2 may be formed to different depths, but this configuration has the advantage of making it easier to form the discharge channel 72 and the second section n2. The “depth” of a channel refers to the depth of the channel in the Z direction, e.g., the difference in elevation between the channel formation surface and the bottom surface of the channel.

[0188] Any one discharge path 72 in the first portion P1 is located on the circulation liquid chamber 65 side when viewed from the nozzle N in the first row L1 that corresponds to that discharge path 72. Additionally, any one discharge path 72 in the second portion P2 is located on the circulation liquid chamber 65 side when viewed from the nozzle N in the second row L2 that corresponds to that discharge path 72. The side of each discharge path 72 opposite to the central plane O overlaps with the corresponding communicating path 63 in plan view. That is, the discharge path 72 communicates with the communicating path 63. On the other hand, the end of each discharge path 72 on the central plane O side overlaps with the circulation liquid chamber 65 in plan view. That is, the discharge path 72 communicates with the circulation liquid chamber 65. In this way, each of the multiple communicating paths 63 communicates with the circulation liquid chamber 65 via the discharge path 72. Therefore, the inkjet composition in each communicating path 63 is supplied to the circulation liquid chamber 65 via the discharge path 72. That is, in this embodiment, the plurality of communication passages 63 corresponding to the first row L1 and the plurality of communication passages 63 corresponding to the second row L2 are in communication with one circulating fluid chamber 65 in common.

[0189] FIG. 4 illustrates the flow path length La of a portion of any one discharge path 72 overlapping with the circulating fluid chamber 65, the flow path length Lb of a portion of the discharge path 72 overlapping with the communicating passage 63, i.e., the flow path length in the X direction, and the flow path length Lc of a portion of the discharge path 72 overlapping with the partition wall 69 of the flow path forming section 30, i.e., the flow path length Lc in the X direction. The flow path length Lc corresponds to the thickness of the partition wall 69. The partition wall 69 functions as a throttle portion of the discharge path 72. Therefore, the longer the flow path length Lc, which corresponds to the thickness of the partition wall 69, the greater the flow path resistance of the discharge path 72. The relative lengths of the flow path length La and the flow path length Lc are arbitrary, but in this example, the relationship is established that the flow path length La is longer than the flow path length Lb, and the flow path length La is longer than the flow path length Lc. Furthermore, in this example, the relationship is established that the flow path length Lb is longer than the flow path length Lc. The above configuration has the advantage that the ink jet composition can more easily flow from the communicating passage 63 through the discharge path 72 into the circulating liquid chamber 65, compared to a configuration in which the flow path length La and the flow path length Lb are shorter than the flow path length Lc.

[0190] As described above, in the inkjet head 2, the pressure chamber C is indirectly connected to the circulating liquid chamber 65 via the communicating passage 63 and the discharge path 72. That is, the pressure chamber C is not directly connected to the circulating liquid chamber 65. In the above configuration, when the pressure in the pressure chamber C fluctuates due to the operation of the piezoelectric element 44, a portion of the inkjet composition flowing in the communicating passage 63 is ejected to the outside from the nozzle N, and the remaining portion flows from the communicating passage 63 via the discharge path 72 into the circulating liquid chamber 65. The inertances of the communicating passage 63, the nozzle N, and the discharge path 72 are selected so that the amount of the inkjet composition flowing through the communicating passage 63 in a single actuation of the piezoelectric element 44 that is ejected via the nozzle N exceeds the amount of the inkjet composition flowing through the communicating passage 63 that flows into the circulating liquid chamber 65 via the discharge path 72. Assuming that all the piezoelectric elements 44 are driven simultaneously, it can be said that the total amount of circulation flowing into the circulating fluid chamber 65 from the multiple communicating passages 63, for example, the flow rate within the circulating fluid chamber 65 per unit time, is greater than the total amount of injection from the multiple nozzles N.

[0191] For example, the recording apparatus 1 is configured to include a circulation mechanism. The circulation mechanism is a mechanism for supplying, i.e., circulating, the inkjet composition in the circulation liquid chamber 65 to the liquid storage chamber R. The circulation mechanism is configured to include, for example, a suction mechanism, such as a pump, that sucks the inkjet composition from the circulation liquid chamber 65, and a heating mechanism that heats the inkjet composition. The inkjet composition is supplied from the circulation mechanism to the liquid storage chamber R via the inlet 482. As a result, the inkjet composition circulates through the following route: liquid storage chamber R → supply channel 61 → pressure chamber C → communicating channel 63 → discharge channel 72 → circulating liquid chamber 65 → circulation mechanism → liquid storage chamber R. In other words, the circulation flow path has a path that allows the inkjet composition to pass through the pressure chamber C and flow back into the pressure chamber C.

[0192] In this way, when the discharge paths 72 that communicate between the communication paths 63 and the circulation liquid chamber 65 are formed in the nozzle plate 52, it is possible to efficiently circulate the inkjet composition near the nozzles N to the circulation liquid chamber 65. Furthermore, since the communication paths 63 corresponding to the first row L1 and the communication paths 63 corresponding to the second row L2 communicate with a common circulation liquid chamber 65 therebetween, there is an advantage that the structure of the inkjet head is simplified and therefore more compact than in a structure in which a circulation liquid chamber communicated with each of the discharge paths 72 corresponding to the first row L1 and a circulation liquid chamber communicated with each of the discharge paths 72 corresponding to the second row L2 are separately provided.

[0193] Note that the discharge path 72 and the nozzle N may be configured to be continuous with each other, instead of being spaced apart from each other. In addition to the circulating fluid chamber 65, a circulating fluid chamber may be formed corresponding to each of the first portion P1 and the second portion P2.

[0194] The inkjet head 2 is equipped with a pressure chamber C that applies pressure to the inkjet composition to eject it from the nozzle. As shown in the example of FIG. 3, it is preferable that a circulation flow path circulates the inkjet composition that has passed through the pressure chamber C. This allows the inkjet composition that has passed through the pressure chamber C to be circulated and supplied again to the pressure chamber. In this case, the discharge path can be provided in the pressure chamber or at a position downstream of the pressure chamber. This is preferable as it provides particularly excellent ejection stability.

[0195] Alternatively, the circulation flow path may have a discharge path provided at a position upstream of the pressure chamber in the inkjet head, and the inkjet composition may be discharged and circulated through the discharge path. The inkjet composition may then be circulated and supplied to the same position again. In this case, the inkjet composition is circulated before passing through the pressure chamber. An example of the upstream position is the liquid storage chamber R.

[0196] The circulation flow path may circulate the inkjet composition that has passed through the discharge path within the inkjet head and supply it again to the inkjet composition path, or may be configured to discharge the inkjet composition that has passed through the discharge path to the outside of the inkjet head 2 and supply the discharged inkjet composition again to the inkjet head, thereby circulating the inkjet composition. Of these, the former is preferred in terms of ease of manufacturing the circulation flow path, etc.

[0197] [3] Recorded material Next, the recorded matter according to the present invention will be described.

[0198] The recorded matter according to the present invention is produced using the recording method and recording apparatus according to the present invention as described above.

[0199] Such a recorded matter has a printed portion that is excellent in gloss and in which the occurrence of defects is prevented.

[0200] The recorded matter according to the present invention may be used for any purpose, for example, decorative items or other applications. Specific examples of the recorded matter according to the present invention include vehicle interior parts such as console lids, switch bases, center clusters, interior panels, emblems, center consoles, and meter nameplates, operating parts for various electronic devices, decorative parts that exhibit decorative properties, indicators, logos, and other displays.

[0201] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0202] For example, the recording apparatus to which the present invention is applied is not limited to the above-mentioned ones, as long as the inkjet head is provided with a circulation flow path for circulating the inkjet composition.

[0203] More specifically, in the above-described embodiment, a serial type printing apparatus is described which is equipped with a serial type inkjet head and performs a serial type printing method, but the printing apparatus of the present invention may also be a printing apparatus which is equipped with, for example, a line type inkjet head.

[0204] Furthermore, the recording method of the present invention may further include other steps in addition to the steps described above. [Example]

[0205] Next, specific examples of the present invention will be described. [4] Preparation of inkjet composition (Preparation Example 1) 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.

[0206] Next, a release resin solubilized with acetone was coated on the entire surface of one side of the film using a roll coater to form a release layer.

[0207] The polyethylene terephthalate film on which the release layer was formed was transported into a vacuum deposition device at a speed of 5 m / s, and a 15 nm thick film made of Al was formed under reduced pressure.

[0208] 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, which is an aggregate of Al metal particles.

[0209] Next, 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.

[0210] Next, this suspension was treated in a high-power circulating ultrasonic crusher to crush the metal particles to a predetermined size by applying ultrasonic waves of 20 kHz.

[0211] Next, a polyoxyalkyleneamine compound represented by the above formula (3) was added to the suspension in a predetermined ratio, and the suspension was subjected to heat treatment at 55°C for 1 hour under 40kHz ultrasonic irradiation, thereby dispersing the metal particle aggregates into primary particles. Here, the polyoxyalkyleneamine compound used was a block copolymer in which an amino group is bonded to the end of consecutive oxyethylene units and a methyl group is bonded to the end of consecutive oxypropylene units, and which satisfies the condition that x1 / x2 between x1 and x2 in the above formula (3) is 3.1 and has a weight-average molecular weight of 2000.

[0212] Furthermore, FHP was added as a fluorine-based phosphorus compound, a hydrophobic phosphorus-based surface treatment agent. FHP is a compound represented by the formula 2-(perfluorohexyl)ethylphosphonic acid: CF3(CF2)5(CH2)2P(O)-(OH)2. The mixture was then subjected to a heat treatment at 55°C for 3 hours under 28 kHz ultrasonic irradiation, causing the FHP to react with the surfaces of the metal particles, resulting in a dispersion of metal particles with extremely low surface free energy and high leafing ability.

[0213] To the obtained dispersion of metal particles, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, UC-3000 (manufactured by Toagosei Co., Ltd., an acrylic resin) as a binder, and BYK-333 (manufactured by BYK Japan, a silicone surfactant) as a surfactant were added in predetermined proportions to obtain a composition for inkjet printing.

[0214] The metal particles contained in the inkjet composition thus obtained had a volume average particle diameter D50 of 0.40 μm.

[0215] (Preparation Examples 2 to 21) Inkjet compositions were prepared in the same manner as in Preparation Example 1, except that the metallic pigments were configured as shown in Tables 1 and 2, and the types and ratios of raw materials used in preparing the inkjet compositions were changed to obtain the compositions shown in Tables 1 and 2. In each preparation example in the table, the total content (by mass) of each component was taken as 100.

[0216] The constitution of the metal pigment contained in the inkjet composition and the composition of the inkjet composition for each of the preparation examples are summarized in Tables 1 and 2. In the tables, the polyoxyalkyleneamine compound represented by the above formula (3), which satisfies the condition that x1 / x2 between x1 and x2 is 3.1 and has a weight average molecular weight of 2000, is referred to as "POAA1", diethylene glycol diethyl ether is referred to as "DEDG", diethylene glycol methyl ethyl ether is referred to as "MEDG", 2-(perfluorohexyl)ethylphosphonic acid, which is a hydrophobic phosphorus-based surface treatment agent, is referred to as "FHP", octadecylphosphonic acid, which is a hydrophobic phosphorus-based surface treatment agent, is referred to as "C18", and dodecylphosphonic acid, which is a hydrophobic phosphorus-based surface treatment agent, is referred to as "C12". "," octylphosphonic acid, a hydrophobic phosphorus-based surface treatment agent, was designated "C8," a silane coupling agent, a fluorinated alkylsilane compound (1H,1H,2H,2H-perfluorodecyltriethoxysilane) manufactured by Sigma-Aldrich, was designated "SC," a surface treatment agent prepared using 1 part by mass of tetraethoxysilane and 1.6 parts by mass of 28% by mass aqueous ammonia was designated "SiO2," BYK-333 (manufactured by BYK Japan) as a surfactant was designated "BYK-333," and UC-3000 (manufactured by Toagosei) as a binder was designated "UC-3000." POAA1 was a block copolymer in which an amino group was bonded to the end of consecutive oxyethylene units and a methyl group was bonded to the end of consecutive oxypropylene units. Furthermore, for the metal pigment constituting the inkjet composition of each of the above preparation examples, observations were performed on 50 randomly selected metal particles from each. As a result, when observed from the direction in which the projected area is maximum, that is, when viewed in plan view, the area S1 [μm 2 ] and the area S0 [μm2 The ratio S1 / S0 to the total volume of the ink was calculated, and the average value of these values ​​was found to be 19 or greater. The average thickness in the table was determined by atomic force microscopy using a NanoNavi E-Sweep (manufactured by SII Nano Technology Inc.). The volume average particle diameter D50 in the table was determined by measurement using a Microtrac MT-3000 (a laser diffraction / scattering particle size distribution analyzer manufactured by Microtrac-Bell Inc.). The viscosity of the inkjet compositions of each of the above Preparation Examples at 25°C, measured using a vibration viscometer in accordance with JIS Z8809, was in the range of 3 mPa·s or greater and 15 mPa·s or less.

[0217] [Table 1]

[0218] [Table 2]

[0219] [5] Production of recorded materials Example 1 First, a recording device was prepared by modifying a Seiko Epson SC-S80650 to have the configuration shown in Figures 1 to 4, with a nozzle row nozzle density of 360 npi and 360 nozzles, and the inkjet composition of Preparation Example 1 was filled in. After confirming that all nozzles of the recording device were ejecting normally without any missing or bent nozzles, the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow path to the maximum ejection rate of the inkjet head was adjusted to 5.0, and droplets of the inkjet composition of Preparation Example 1 were ejected continuously in this state for two hours, whereby the deposition amount of the solid content of the inkjet composition on a vinyl chloride film (Scotchcal Graphics Film IJ8150, manufactured by 3M) as a recording medium was 3 mg / inch. 2The inkjet composition was applied to the recording medium at a recording resolution of 1440 x 1440 dpi, and the platen and after-heater media temperatures were set at 45°C and 50°C, respectively.

[0220] Examples 2 to 20 Recorded matter was produced in the same manner as in Example 1, except that the type of inkjet composition was changed to one shown in Table 3 and the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow path to the maximum ejection rate of the inkjet head was adjusted as shown in Table 3.

[0221] (Comparative Examples 1 to 3) Recorded matter was produced in the same manner as in Example 1, except that the type of inkjet composition was changed to that shown in Table 3.

[0222] Comparative Example 4 The recording device was the same as in Example 2 except that an inkjet head without a circulation flow path was used as the recording device.

[0223] (Comparative Examples 5 to 7) Recorded matter was produced in the same manner as in Comparative Example 4, except that the type of inkjet composition was changed to that shown in Table 3.

[0224] [6] Evaluation The following evaluations were carried out for each of the examples and comparative examples. [6-1] Gloss stability During the production of the recorded matter according to each of the Examples and Comparative Examples, the gloss value of the recorded portion formed by the inkjet composition adhering to the recording medium was measured every 10 minutes from the start of ejection, and the maximum and minimum values ​​of each measurement value until the ejection of the inkjet composition was completed were determined. The difference between these values ​​was calculated from the results and evaluated according to the following criteria. The smaller this value, the better the gloss stability. A level of B or higher was determined as good.

[0225] The gloss was measured using a gloss meter, MINOLTA MULTI GLOSS 268, at a tilt angle of 60°.

[0226] AA: The difference between the maximum and minimum values ​​is 5° or less. A: The difference between the maximum and minimum values ​​is more than 5° and not more than 10°. B: The difference between the maximum and minimum values ​​is more than 10° and not more than 20°. D: The difference between the maximum and minimum values ​​is more than 20°.

[0227] [6-2] Gloss value In the above [6-1], the average gloss value was calculated every 10 minutes and evaluated according to the following criteria. The higher this value, the better the gloss value. A value of B or higher was considered to be good.

[0228] AA: The average gloss value is 600° or more. A: The average gloss value is less than 600° and 500° or more. B: The average gloss value is less than 500° and 400° or more. D: The average gloss value is less than 400°.

[0229] [6-3] Discharge stability During the production of the recorded matter relating to each of the above-mentioned Examples and Comparative Examples, each nozzle was inspected for the presence or absence of ejection defects every 10 minutes from the start of ejection, and nozzles that were experiencing non-ejection or deflected ink flight were determined as ejection-defective nozzles, and the percentage of ejection-defective nozzles at each time point was calculated. From the results, the average value for each time period was calculated as the average rate of ejection-defective nozzles, and evaluated according to the following criteria. The smaller this value, the better the ejection stability. A grade of C or higher was determined as good.

[0230] A: The average rate of defective nozzles is less than 10%. B: The average rate of defective nozzles is 10% or more and less than 20%. C: The average rate of defective nozzles is 20% or more and less than 30%. D: The average rate of defective nozzles is 30% or more.

[0231] These results, together with the production conditions of the recorded matter according to each of the Examples and Comparative Examples, are summarized in Table 3. In Table 3, the ratio of the circulation flow rate of the inkjet composition circulating through the circulation flow path to the maximum discharge rate of the inkjet head is shown as the "circulation flow rate ratio."

[0232] [Table 3]

[0233] As is clear from Table 3, excellent results were obtained in the present invention. In contrast, satisfactory results were not obtained in the comparative examples. [Explanation of symbols]

[0234] 1...recording device, 2...inkjet head, 3...IR heater, 4...platen heater, 5...heating heater, 6...cooling fan, 7...preheater, 8...ventilation fan, 9...carriage, 11...platen, 12...cartridge, 13...carriage movement mechanism, 14...transport means, 28...wiring board, 30...flow path forming section, 32...first flow path board, 34...second flow path board, 42...vibration section, 44...piezoelectric element, 46...protective member, 48...casing section, 482...inlet, 52...nozzle plate, 54...vibration absorber, 61...supply path, 63 ...Communicating passage, 65...Circulating liquid chamber, 69...Partition wall portion, 72...Discharge passage, C...Pressure chamber, d1...Inner diameter, d2...Inner diameter, Da...Depth, Fa...Surface, Fb...Surface, L1...First row, L2...Second row, La...Flow path length, Lb...Flow path length, Lc...Flow path length, M...Recording medium, MS...Main scanning direction, N...Nozzle, n1...First section, n2...Second section, O...Center plane, P1...First part, P2...Second part, Qa...Center axis, Qb...Center axis, R...Liquid storage chamber, Ra...Space, Rb...Space, S1...Arrow, S2...Arrow, SS...Sub-scanning direction, T1...Arrow, T2...Arrow

Claims

1. A recording method for recording on a recording medium using a recording device equipped with an inkjet head, comprising: ejecting the inkjet composition from the inkjet head; the inkjet composition contains a metal pigment, is a solvent-based ink, and contains a glycol ether as an organic solvent; the metal pigment is composed of a plurality of scale-like metal particles, The volume average particle diameter D50 of the metal particles is 0.90 μm or less, the metal particles have been surface-treated with a phosphorus compound, the phosphorus compound has an alkyl group having 12 or more carbon atoms, does not have a polyoxyethylene structure, and is not an amine compound; the inkjet head is provided with a circulation flow path for circulating the inkjet composition, A recording method, wherein the metal particles have an average thickness of 19 nm or less as determined by atomic force microscopy.

2. The recording method according to claim 1 , wherein the content of the metal particles in the inkjet composition is 0.2% by mass or more and 4.0% by mass or less.

3. 3. The recording method according to claim 1, wherein the metal particles are made of a material containing aluminum or an aluminum alloy.

4. 4. The recording method according to claim 1, wherein the phosphorus compound has an alkyl group having 15 or more carbon atoms.

5. 5. The recording method according to claim 1, wherein the volume average particle diameter D50 of the metal particles is 0.20 [mu]m or more and 0.90 [mu]m or less.

6. 6. The recording method according to claim 1, wherein the average aspect ratio of the metal particles, which is the ratio of the volume average particle diameter D50 of the metal particles to the average thickness of the metal particles determined by atomic force microscopy, is 20 or more and 2000 or less.

7. 7. The recording method according to claim 1, wherein the metal particles have an average thickness of 5 nm or more and 19 nm or less as determined by atomic force microscopy.

8. A recording method described in any one of claims 1 to 7, wherein the recording medium is a non-absorbent recording medium.

9. 9. The recording method according to claim 1, wherein a ratio of a circulation flow rate of the inkjet composition circulating through the circulation flow path to a maximum ejection rate of the inkjet head is 0.50 or more and 15 or less.

10. Equipped with an inkjet head, A recording apparatus for carrying out the recording method according to claim 1 , wherein the inkjet head is provided with a circulation flow path for circulating the inkjet composition.

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