Liquid ejection device, printing device

Abstract

To provide a device capable of performing efficient drying while reducing an environmental load.SOLUTION: A device includes ejection units 33A to 33D which eject first liquid 801 comprising aqueous pigment inks of respective colors C, M, Y, K capable of generating heat in an absorption wavelength region of ultraviolet rays, an ejection unit 33E which ejects second liquid 802 comprising ultraviolet-curable ink of color W capable of initiating polymerization in the absorption wavelength region of ultraviolet rays, and ultraviolet rays irradiation means 521 which irradiates sheet material P to which the first liquid 801 and the second liquid 802 are applied, with ultraviolet rays of wavelength of absorption wavelength region.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a liquid ejecting device and a printing device. [Background technology]

[0002] 2. Description of the Related Art Printing devices that apply liquid to a printing target such as a sheet material to perform printing include those that use liquid that hardens when exposed to active energy rays such as ultraviolet rays, and those that heat and dry the liquid applied to the sheet material by irradiating it with ultraviolet rays. There are some.

[0003] Conventionally, for example, there is a method using an active energy ray-curable water-based ink (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-180436 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, active energy ray curable inks, such as ultraviolet ray curable inks, have a problem in that they impose a greater environmental load than water-based pigment inks.

[0006] The present invention has been made in view of the above problems, and has an object to perform efficient drying while reducing the environmental load. [Means for solving the problem]

[0007] In order to solve the above problems, a liquid ejection device according to the present invention comprises: Ultraviolet rays a first discharge means for discharging a first liquid that generates heat in an absorption wavelength region of the The above Ultraviolet rays Polymerization begins in the absorption wavelength range of whiteA second discharge means for discharging liquid onto the medium; A conveying means for conveying the medium; A means for irradiating infrared rays; The above Ultraviolet rays and a means for irradiating the light, the first discharge means discharges the first liquid onto the medium after the second discharge means has discharged the white liquid onto the medium; The conveying means conveys the medium that has passed through the infrared ray irradiating means to the Ultraviolet rays to a means for irradiating the The composition was as follows.

[0008] According to the present invention, efficient drying can be performed while reducing the environmental load. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of a printing apparatus as a liquid ejecting apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view illustrating a discharge unit of the printing apparatus. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 2 is a perspective view illustrating an example of an ultraviolet ray irradiation means. [Figure 6] 4 is an explanatory diagram of an example of reflectance of each color with respect to an ultraviolet wavelength, to be provided for explaining the operation of the embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. A printing apparatus as a liquid ejecting apparatus according to a first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic explanatory diagram of the printing apparatus, and Figure 2 is a plan explanatory diagram of an ejection unit of the printing apparatus.

[0011] The printing device 1 includes an input section 10 for inputting the sheet material P, a pre-treatment section 20 which is an application section, a printing section 30, a first drying section 40, a second drying section 50, an inversion mechanism section 60, and an output section 70.

[0012] The printing device 1 applies (coats) a pretreatment liquid as a coating liquid to the sheet material P transported (supplied) from the transport section 10 in the pretreatment section 20 as necessary, and then applies the required liquid to the sheet material P in the printing section 30 to perform the required printing.

[0013] Then, the printing device 1 dries the liquid adhering to the sheet material P in the first drying section 40 and the second drying section 50, and then discharges the sheet material P to the discharge section 70 via the inversion mechanism section 60, either as is or after printing on both sides of the sheet material P.

[0014] The loading section 10 includes an input tray 11 (lower input tray 11A, upper input tray 11B) that stores multiple sheet materials P, and a feeding device 12 (12A, 12B) that separates and sends out the sheet materials P one by one from the input tray 11, and supplies the sheet materials P to the pre-processing section 20.

[0015] The pre-treatment section 20 includes, for example, an application section 21 which is a treatment liquid application section that applies a treatment liquid having an effect of agglomerating ink and preventing show-through to the printing surface of the sheet material P.

[0016] The printing unit 30 includes a drum 31 which is a support member (rotating member) that supports the sheet material P on its circumferential surface and rotates, and a liquid ejection unit 32 which ejects liquid toward the sheet material P supported by the drum 31.

[0017] The printing section 30 includes a transfer cylinder 34 which receives the sheet material P sent from the pre-treatment section 20 and transfers the sheet material P between the drum 31, and a transfer cylinder 35 which receives the sheet material P transported by the drum 31 and transfers it to the first drying section 40.

[0018] The sheet material P transported from the pre-processing section 20 to the printing section 30 has its leading edge gripped by a gripping means (sheet gripper) provided on the transfer cylinder 34, and is transported as the transfer cylinder 34 rotates. The sheet material P transported by the transfer cylinder 34 is delivered to the drum 31 at a position opposite to the drum 31.

[0019] A gripping means (sheet gripper) is also provided on the surface of the drum 31, and the leading end of the sheet material P is gripped by the gripping means (sheet gripper). A plurality of suction holes are formed in a dispersed manner on the surface of the drum 31, and the suction means generates a suction airflow that flows inward from the required suction holes of the drum 31.

[0020] Then, the sheet material P transferred from the transfer cylinder 34 to the drum 31 has its leading edge gripped by the sheet gripper, and is adsorbed and supported on the drum 31 by the suction airflow of the suction means, and is transported as the drum 31 rotates.

[0021] The liquid discharge section 32 includes discharge units 33 (33A to 33E) which are liquid discharge means serving as liquid application means. For example, the discharge unit 33A discharges cyan (C) liquid, the discharge unit 33B discharges magenta (M) liquid, the discharge unit 33C discharges yellow (Y) liquid, the discharge unit 33D discharges black (K) liquid, and the discharge unit 33E discharges white (W) liquid. In addition, a discharge unit that discharges a special liquid such as gold (silver) can also be used.

[0022] The ejection unit 33 has a head module 100 including a full-line head in which a plurality of liquid ejection heads (hereinafter simply referred to as "heads") 101, each having a plurality of nozzle rows in which a plurality of nozzles 111 are arranged, are arranged in a staggered pattern on a base member 103, as shown in FIG.

[0023] The discharge operation of each discharge unit 33 of the liquid discharge section 32 is controlled by a drive signal corresponding to the printing information. When the sheet material P supported on the drum 31 passes through an area facing the liquid discharge section 32, liquid of each color is discharged from the discharge unit 33, and an image corresponding to the printing information is printed.

[0024] The first drying section 40 includes a heating means 42 such as an IR heater, and irradiates infrared rays to heat and dry the sheet material P to which the liquid has been applied and which is being transported by the transport section 41. The second drying section 50 includes a heating means 52 that irradiates ultraviolet rays as active energy rays, and irradiates ultraviolet rays to heat and dry the sheet material P to which the liquid has been applied and which has passed through the first drying section 40 and is being transported by the transport section 51. The transport sections 41 and 51 are configured as parts of the same transport means.

[0025] The reversing mechanism 60 includes a reversing section 61 that reverses the sheet material P using a switchback method when performing double-sided printing on the sheet material P that has passed through the first drying section 40 and the second drying section 50 and has had liquid applied to one side and been dried, and a double-sided conveying section 62 that sends the reversed sheet material P back upstream of the transfer drum 34 of the printing section 30.

[0026] The discharge section 70 includes a discharge tray 71 on which a plurality of sheet materials P are stacked. The sheet materials P conveyed from the reversing mechanism section 60 are successively stacked and held on the discharge tray 71.

[0027] In this embodiment, an example is described in which the sheet material is cut sheet material, but the present invention can also be applied to devices that use continuous bodies (webs) such as continuous paper or rolled paper, and devices that use sheet materials such as wallpaper.

[0028] Here, the liquid discharged from the discharge unit will be described.

[0029] The ejection units 33A to 33D are first ejection means that eject a first liquid 801 (FIG. 3) that generates heat in the absorption wavelength region of ultraviolet light as an active energy ray. The first liquid 801 is a water-based pigment ink. That is, water-based pigment inks are used as the inks of the respective colors C, M, Y, and K (inks other than white).

[0030] A typical composition of aqueous pigment ink is about 90% water and other high boiling point solvents, about 5% resin, and about 5% pigment coloring material, but is not limited to this. Specific examples of pigment coloring materials that can be used include K carbon black, C copper phthalocyanine, M quinacridone, and Y monoazo yellow. By using such pigment coloring materials, it is possible to obtain vivid printed images that do not fade even when exposed to ultraviolet light, unlike inks that use dye coloring materials.

[0031] The discharge unit 33E is a second discharge means for discharging a second liquid 802 (FIG. 3) that starts to polymerize in the absorption wavelength region of ultraviolet light as an active energy ray. The second liquid 802 is an ultraviolet curable ink. That is, an ultraviolet curable ink is used as the W ink (white ink).

[0032] UV-curable ink contains a UV-polymerization initiator and a UV-polymerizable monomer, and when irradiated with UV light, the polymerization initiator becomes active in a radical or cationic state, which reacts with the monomer, polymerizing the monomer and curing it as a resin. By using UV-curable ink for the white ink, cockling in the white area can be suppressed.

[0033] Next, an example of the heating device will be described with reference to Figures 3 and 4. Figure 3 is a side view of the heating device, and Figure 4 is a front view of the same.

[0034] The heating device 500 of the second drying section 50 has a transport mechanism section 501 which is a transport means, and an ultraviolet ray irradiation section 502 which is a heating means 52. The heating device 500 constitutes the second drying section 50.

[0035] The conveying mechanism 501 has a conveying belt 511 that carries and conveys the sheet material P. The conveying belt 511 is looped around a driving roller 512 and a driven roller 513 and moves in a circular motion. In this embodiment, the conveying mechanism 501 is a mechanism that conveys the sheet material P from the printing unit 30 to the reversing mechanism 60 as shown in FIG.

[0036] The conveyor belt 511 is a belt having a plurality of openings that are sucked by a suction chamber 514 disposed inside. For example, a mesh belt or a flat belt having suction holes is used. The suction chamber 514 performs suction using a suction blower, a fan, or the like. The conveyor is not limited to a conveyor using a suction method, and may be a conveyor that conveys the sheet material P using, for example, an electrostatic adsorption method or a gripper gripping method.

[0037] The ultraviolet ray irradiation section 502 includes a plurality of ultraviolet ray irradiation means 521 arranged along the conveying direction in a housing 503. The ultraviolet ray irradiation means 521 irradiates the sheet material P conveyed by the conveying mechanism section 501 with ultraviolet rays to heat it.

[0038] As shown in FIG. 3, the housing 503 is arranged with a gap between it and the conveyor belt 511 in the direction along the conveying direction, and as shown in FIG. 4, in the direction perpendicular to the conveying direction, the housing 503 has a portion 503a that extends below the conveyor belt 511 in the height direction.

[0039] Next, an example of the ultraviolet ray irradiation means will be described with reference to Fig. 5. Fig. 5 is a perspective explanatory view of the example of the ultraviolet ray irradiation means.

[0040] The ultraviolet irradiation means 521 has granular UV-LED light emitting elements 523 arranged in a lattice pattern on an irradiation surface 522. Each UV-LED light emitting element 523 emits light with the same illuminance, resulting in a state in which light is emitted uniformly along the irradiation surface 522 as a whole. The ultraviolet light (UV light) used has a peak wavelength of 395 nm and a wavelength distribution with a full width at half maximum of approximately 15 nm.

[0041] Next, the operation of this embodiment will be described with reference to Fig. 6. Fig. 6 is an explanatory diagram of an example of the reflectance of each color with respect to the ultraviolet wavelength, which is provided for explaining the operation.

[0042] Process color pigment inks such as black, cyan, magenta, and yellow (Figure 6), as well as special color pigment inks such as orange, green, and violet, have absorption wavelengths in the ultraviolet wavelength range (380 to 400 nm) and generate heat.

[0043] Therefore, by irradiating the aqueous pigment ink (first liquid 801) applied to the sheet material P with ultraviolet light of a wavelength (380 to 400 nm) from the ultraviolet light irradiation means 521, the ultraviolet light acts on the absorption wavelength range of the coloring material in the aqueous pigment ink and the composition in the ink, generating heat and drying the ink.

[0044] On the other hand, when an aqueous pigment ink is used for white, the coloring material in the aqueous pigment ink and the ink composition have low absorption (high reflectance) in the ultraviolet absorption wavelength region (380 to 400 nm), so heat generation is difficult and drying is insufficient, as shown in Figure 6. Also, white ink is mainly used as the white part of an image on non-white media.

[0045] In other words, since the water-based pigment-based white ink absorbs less ultraviolet light and does not generate heat, it is slow to dry, which can cause problems such as soiling the transport path and adhering and sticking to overlapping sheet materials after ejection, causing the image to peel off when the sheet materials P are separated.

[0046] Therefore, in this embodiment, for white, ultraviolet curable ink (second liquid 802) is used. By using ultraviolet curable ink, the monomer undergoes a polymerization reaction when ultraviolet light in the absorption wavelength range (380 to 400 nm) is irradiated by the ultraviolet irradiation means 521, and the ink becomes hardened and dried.

[0047] As a result, even when white ink is used, an image can be obtained in which cockling does not occur in the white portion, and the inside of the conveying path is prevented from being soiled with undried ink.

[0048] Furthermore, by limiting the use of active energy curable inks, which have a relatively large environmental impact, to white ink, it is possible to reduce the environmental impact while performing efficient drying.

[0049] In addition, the ultraviolet ray irradiation means 521 used for drying is a single unit that can act on both water-based pigment inks (black, cyan, magenta, yellow, orange, green, violet) and white ink, leading to miniaturization and cost reduction of the device.

[0050] Here, the liquid compositions used as the first liquid and the second liquid will be described.

[0051] The liquid composition contains water or an organic solvent, and if necessary, contains other components such as a coloring material, a resin, etc. The active energy curable liquid composition contains an ultraviolet polymerization initiator and an ultraviolet polymerizable compound.

[0052] When the liquid composition contains a coloring material such as a pigment or dye, the coloring material absorbs the light irradiated by the irradiation means and converts it into thermal energy, generating heat. As the temperature of the liquid composition rises, water and organic solvents evaporate, and when the liquid composition contains a resin, the resin melts, and the printed image is fixed to the sheet material.

[0053] -UV polymerization initiators and UV polymerizable compounds- When the liquid composition contains an ultraviolet polymerization initiator and an ultraviolet polymerizable compound, the content of the ultraviolet polymerization initiator in the liquid composition is preferably less than 0.1 mass %, or the content of the ultraviolet polymerizable compound in the liquid composition is preferably less than 5 mass %.

[0054] Examples of ultraviolet polymerization initiators include those that can generate active species such as radicals and cations by UV (ultraviolet rays) and initiate polymerization of polymerizable compounds (monomers and oligomers). As such polymerization initiators, known radical polymerization initiators, cationic polymerization initiators, base generators, etc. are used alone or in combination of two or more.

[0055] Examples of the radical polymerization initiator include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.

[0056] The ultraviolet-polymerizable compound is not particularly limited and can be appropriately changed. For example, a known polymerizable compound can be used. The polymerizable compound may be a monomer or an oligomer. For example, methacrylic acid can be used.

[0057] -water- The water content in the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of drying property and ejection reliability, however, it is preferably from 10% by mass to 90% by mass, and more preferably from 20% by mass to 60% by mass.

[0058] -Organic solvents- The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples of the organic solvent include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

[0059] Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, and 1,4-pentanediol. Examples of such hexanediol include 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol.

[0060] Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.

[0061] Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0062] Examples of the nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Examples of the amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.

[0063] Examples of the amines include monoethanolamine, diethanolamine, and triethylamine.

[0064] Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol.

[0065] Other organic solvents include propylene carbonate, ethylene carbonate, and the like.

[0066] It is preferable to use an organic solvent having a boiling point of 250° C. or less, since this not only functions as a wetting agent but also provides good drying properties.

[0067] As the organic solvent, polyol compounds having 8 or more carbon atoms and glycol ether compounds are also suitably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

[0068] Specific examples of the glycol ether compound include polyhydric alcohol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; and polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0069] Polyol compounds having 8 or more carbon atoms and glycol ether compounds can improve the permeability of ink when paper is used as the recording medium.

[0070] The content of the organic solvent in the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of drying property and ejection reliability, however, the content is preferably from 10% by mass to 60% by mass, and more preferably from 20% by mass to 60% by mass.

[0071] -Water and organic solvent content- The total amount of water and organic solvent in the liquid composition is 80% by mass or more. It is preferable that the content of the water-soluble polymer is 90% by mass or more, and more preferable that the content of the water-soluble polymer is 90% by mass or more. It is possible.

[0072] -Coloring materials- The coloring material is not particularly limited, and pigments and dyes can be used. As the pigment, an inorganic pigment or an organic pigment can be used. These pigments can be used alone or in combination of two or more. Also, mixed crystals can be used as the pigment.

[0073] Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.

[0074] As inorganic pigments, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method can be used.

[0075] As organic pigments, azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0076] Specific examples of pigments for black colors include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (CI Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (CI Pigment Black 1).

[0077] In addition, for color, CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, CI Pigment Yellow Range 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88 , 101 (red oxide), 104, 105, 106, 108 (cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.

[0078] The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. One type of dye may be used alone, or two or more types may be used in combination.

[0079] Dyes such as CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Acid Black 1, 2, 24, 94, CI Food Black 1, 2, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Directed Black 19, 38, 51, 71, 154, 168, 171, 195, CI Reactive Red 14, 32, 55, 79, 249, and CI Reactive Black 3, 4, and 35.

[0080] The content of the coloring material in the liquid composition is preferably from 0.1% to 15% by mass, and more preferably from 1% to 10% by mass, from the viewpoints of improving image density, good fixing property and ejection stability.

[0081] Methods for dispersing a pigment to obtain a liquid composition include a method of introducing a hydrophilic functional group into a pigment to make it a self-dispersing pigment, a method of dispersing the pigment by coating the surface of the pigment with a resin, and a method of dispersing the pigment using a dispersant. As a method for introducing a hydrophilic functional group into a pigment to make it a self-dispersing pigment, for example, a method in which a functional group such as a sulfone group or a carboxyl group is added to a pigment (e.g., carbon) to make it dispersible in water can be mentioned.

[0082] As a method for dispersing a pigment by coating its surface with a resin, a method for encapsulating the pigment in a microcapsule to make it dispersible in water can be mentioned. This can be called a resin-coated pigment. In this case, it is not necessary for all the pigments to be blended in the liquid composition to be coated with a resin, and uncoated or partially coated pigments may be dispersed in the liquid composition within a range that does not impair the effects of the present invention.

[0083] Examples of the method for dispersing using a dispersant include a method for dispersing using a known low molecular weight dispersant or a known polymeric dispersant, such as a surfactant. As the dispersant, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. can be used depending on the pigment. As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used. The dispersants may be used alone or in combination of two or more.

[0084] A liquid composition such as ink can be obtained by mixing a pigment with materials such as water or an organic solvent. It is also possible to manufacture a liquid composition by mixing a pigment with other materials such as water and a dispersant to prepare a pigment dispersion, and then mixing the pigment with materials such as water and an organic solvent.

[0085] The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. Dispersion is preferably performed using a dispersing machine.

[0086] The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency in terms of the maximum number is preferably 20 nm or more and 500 nm or less, more preferably 20 nm or more and 150 nm or less, in order to improve the dispersion stability of the pigment and the image quality such as ejection stability and image density. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0087] The pigment content in the pigment dispersion is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of obtaining good ejection stability and increasing image density, the pigment content is preferably from 0.1% by mass to 50% by mass, and more preferably from 0.1% by mass to 30% by mass. It is preferable to filter out coarse particles from the pigment dispersion using a filter or a centrifugal separator, and degas the pigment dispersion, if necessary.

[0088] -resin- The type of resin contained in the liquid composition is not particularly limited and can be appropriately selected depending on the purpose. Examples of the resin include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Resin particles made of these resins may be used. The resin particles may be dispersed in water as a dispersion medium to form a resin emulsion, and then mixed with materials such as coloring materials and organic solvents to obtain a liquid composition. The resin particles may be appropriately synthesized or may be commercially available. These may be used alone or in combination of two or more types of resin particles.

[0089] The volume average particle size of the resin particles is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint of obtaining good fixing property and high image hardness, however, it is preferably from 10 nm to 1,000 nm, more preferably from 10 nm to 200 nm, and particularly preferably from 10 nm to 100 nm. The volume average particle size can be measured, for example, using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac-Bell Co., Ltd.).

[0090] The resin content is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoints of fixation property and storage stability of the liquid composition, however, the resin content is preferably from 1 mass % to 30 mass % and more preferably from 5 mass % to 20 mass % of the total amount of the liquid composition.

[0091] -Other ingredients- If necessary, surfactants, antifoaming agents, antiseptic and antifungal agents, rust inhibitors, pH adjusters, etc. may be added to the liquid composition.

[0092] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural colorant, etc., and these can be used for applications such as inkjet ink, surface treatment liquid, a liquid for forming a component of an electronic element or a light-emitting element, an electronic circuit resist pattern, a material liquid for three-dimensional modeling, etc.

[0093] Energy sources for ejecting liquid include piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode.

[0094] Furthermore, the term "device for ejecting liquid" includes not only devices capable of ejecting liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0095] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0096] For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0097] In addition, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0098] The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0099] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

[0100] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, a line type device in which a liquid ejection head does not move, etc.

[0101] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0102] In the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous. [Explanation of symbols]

[0103] 1 Printing device 10 Loading section 20 Pretreatment section 30 Printing Department 40 1st drying section 50 2nd drying section 60 Reversing mechanism 70 Unloading section 500 Heating device 501 Transport mechanism 502 UV irradiation unit 511 Conveyor belt 514 Suction chamber 521 Ultraviolet irradiation means 522 Irradiation surface

Claims

1. A first ejection means for ejecting a first liquid that generates heat in an ultraviolet absorption wavelength range onto a medium; a second ejection means for ejecting a white liquid that initiates polymerization in the absorption wavelength region of the ultraviolet light onto the medium; A conveying means for conveying the medium; A means for irradiating infrared rays; a means for irradiating the ultraviolet light, the first ejection means ejects the first liquid onto the medium after the second ejection means ejects the white liquid onto the medium; The transport means transports the medium that has passed through the infrared ray irradiating means to the ultraviolet ray irradiating means. A liquid ejection device comprising:

2. The first liquid is a water-based pigment ink.

2. The liquid dispensing device according to claim 1.

3. The white liquid is an ultraviolet curable ink.

3. The liquid ejection device according to claim 1 or 2.

4. The irradiating means includes an LED that irradiates ultraviolet light.

4. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

5. The color material is a pigment 5. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

6. The first liquid is an ink of a color other than white.

6. The liquid ejection device according to claim 1, wherein the liquid ejection device is a liquid ejection device.

7. A first ejection means for ejecting a first liquid that generates heat in an ultraviolet absorption wavelength range onto a medium; a second ejection means for ejecting a white liquid that initiates polymerization in the absorption wavelength region of the ultraviolet light onto the medium; A conveying means for conveying the medium; A means for irradiating infrared rays; a means for irradiating the ultraviolet light, the first ejection means ejects the first liquid onto the medium after the second ejection means ejects the white liquid onto the medium; The transport means transports the medium that has passed through the infrared ray irradiating means to the ultraviolet ray irradiating means. A printing device comprising:

Images