JP5924430B2 - Inkjet recording system and recording method - Google Patents

Description

  The present invention relates to an ink jet recording system and a recording method for performing high image quality recording at high speed on a non-ink-absorbing or low-absorbing recording medium.

  Conventionally, as shown in Patent Document 1, it has been proposed that an ink jet recording apparatus is equipped with a preheating lamp and an air blowing means as ink drying means. Among these, the preheating lamp is provided so as to heat the driving roller, and the driving roller is configured to be heated before the recording medium passes through the printing zone. On the other hand, the blowing means is configured to heat the recording medium immediately after printing in the printing zone by applying a strong wind.

Japanese Patent Laid-Open No. 6-126952

  However, when performing inkjet recording at high speed on a recording medium with extremely low ink absorption capability, such as cast paper or plastic film for offset printing, high-speed and high-quality printing is performed with an apparatus using a conventional drying means. It was impossible to do. For example, there are problems such as uneven line width (beading) when ruled lines are printed and color unevenness and mixing of different colors (color bleed) when solid printing is performed.

  The present invention has been made in order to solve at least a part of the above-described problems. In the following forms or modes, inkjet recording is performed at high speed on a recording medium with extremely low ink absorption capability. It is possible to realize a recording system and a recording method.

  In order to achieve the above object, a first aspect is a recording head that ejects ink to the surface of a non-ink-absorbing and low-absorbing recording medium; the recording head that faces the recording head; A medium support unit supported by the recording head, a drying unit as a first fixing unit for evaporating the liquid component of the ink ejected and adhered to the recording medium from the recording head, and transport of the recording medium from the drying unit An ink jet recording system comprising a second fixing unit on the downstream side in the direction, wherein the ink is at least (1) a colorant, and (2) a monomer that is an organic solvent having a boiling point of 100 ° C. to 250 ° C. 3) a polymerizable oligomer and / or polymer, and (4) a photopolymerization initiator, wherein the second fixing unit is an irradiation device that irradiates the recording medium with ultraviolet rays or an electron beam, and the drying unit Evaporation of definitive said liquid component, wherein 40 to 70% by weight of the ink deposited on a recording medium, it is characterized.

  According to the first aspect, the ink jet recording system includes a drying unit as a first fixing unit that evaporates 40 to 70% by weight of the ink attached to the recording medium, and a recording medium fed from the drying unit. An irradiation device for irradiating the recording medium as a second fixing unit provided on the downstream side in the direction with an ultraviolet ray or an electron beam is provided. Therefore, even when printing at high speed, the ink adhering to the recording medium is evaporated by 40% by weight or more in the drying section, so that the line width is not uniform (beading) when the ruled line is printed on the recording medium. In addition, it is possible to prevent occurrence of color unevenness or mixing of different colors (color bleed) when solid printing is performed, and not to evaporate more than 70% by weight of ink adhering to the recording medium in the drying section. In addition, it is possible to secure the dot diameter of the ink droplets on the recording medium, and to prevent the lines from being connected when the ruled lines are printed, or the occurrence of unevenness during the solid printing. In addition, it is possible to prevent a decrease in abrasion resistance due to the thickened dots of ink droplets.

  According to a second aspect, in the ink jet recording system described above, (1) a colorant contained in the ink, (2) a monomer that is an organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower, and (3) a polymerizable oligomer And / or polymer, (4) photopolymerization initiator is (1) 0.2 to 10% by weight of pigment as colorant, (2) allyl glycol, N-vinylformamide as monomer, (2-methyl- 2-ethyl-1,3-dioxolan-4-yl-) methyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, methoxydiethylene glycol monoacrylate, acryloylmorpholine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, 1 , 9-Nona Diol diacrylate, polyethylene glycol # 400 diacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, trimethylolpropane trimethacrylate , Trimethylolpropane-modified triacrylate, trimethylolpropane PO-modified triacrylate, glycerol PO-modified triacrylate, or a single or two or more organic solvents of 30 to 70% by weight, (3) a polymerizable oligomer and / or Alternatively, the polymer is characterized by containing 10 to 50% by weight of a polymer and (4) 3 to 10% by weight of a photopolymerization initiator.

  According to the 2nd aspect, it can employ | adopt suitably as an ink of the 1st aspect of this invention, and the effect of the inkjet recording system by the 1st aspect of this invention can be heightened further.

  According to a third aspect, in the inkjet recording system described above, the ink includes (5) a volatile organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower and / or water.

  According to the 3rd aspect, it can employ | adopt suitably as an ink of the 1st or 2nd aspect of this invention, and the effect of the inkjet recording system by the 1st aspect of this invention can be heightened further.

  A fourth aspect is the ink jet recording system according to the above, wherein (5) a volatile organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower contained in the ink is N-methylpyrrolidone, N-ethylpyrrolidone, N- Vinyl pyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol Diethyl ether, diethylene glycol isopropyl ether, propylene glycol monomethyl ether, dipropylene glycol Methyl ether, dipropylene glycol dimethyl ether, 1,4-dioxane, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol, n-butanol, 1, 2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octanediol, 1,2-pentanediol, triethylene glycol A single selected from the group consisting of monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, propylene glycol monobutyl ether Alternatively, it contains two or more kinds of organic solvents.

  According to the 4th aspect, it can employ | adopt suitably as an ink of the 3rd aspect of this invention, and the effect of the inkjet recording system by the 1st aspect of this invention can be heightened further.

  A fifth aspect is an inkjet recording method using the inkjet recording system described above, wherein the recording head ejects ink onto the surface of the recording medium that is non-ink-absorbing and low-absorbing. In the drying unit, the drying unit causes the liquid component of the ink attached to the recording medium to evaporate by 40 to 70% by weight of the ink and the irradiation device as the second fixing unit. And irradiating the recording medium in which the liquid component is evaporated with ultraviolet rays or electron beams to polymerize and cure the remaining component after the liquid component of the ink is evaporated.

  According to the fifth aspect, the inkjet recording system according to any one of the first to fourth aspects can provide a method of performing inkjet recording at a high speed on a recording medium with extremely low ink absorption capability.

FIG. 2 is a side view illustrating the outline of the entire printer according to the embodiment. FIG. 3 is a side view illustrating an outline of a recording unit of the printer according to the embodiment. FIG. 4 is a side view illustrating an outline of a second fixing unit of the printer according to the embodiment. Print evaluation results of tests 1-6. Print evaluation result of test 7.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an outline of the entire inkjet recording apparatus 1 according to the present embodiment.
As shown in FIG. 1, the inkjet recording apparatus 1 includes a recording medium feeding unit 10, a transport unit 20, a recording unit 30, a fixing unit 90, and a discharge unit 70.

Among these, the fixing unit 90 includes a drying unit 40 and a second fixing unit 50 as first fixing units to be described later.
The feeding unit 10 is provided so that a roll-shaped recording medium F, which is an example of a recording medium, can be fed to the transport unit 20.
Specifically, a roll medium holder 11 is provided, and the roll medium holder 11 holds a roll-shaped recording medium F. Then, by rotating the roll-shaped recording medium F, the recording medium F can be fed to the conveyance unit 20 on the downstream side in the feeding direction.

In this embodiment, the recording medium F will be described, but it is needless to say that it may be paper or plastic film.
The transport unit 20 is provided so that the recording medium F sent from the feeding unit 10 can be transported to the recording unit 30. Specifically, it has the 1st feed roller 21, and it is comprised so that the sent recording medium F can be further conveyed to the recording part 30 of the feed direction downstream.

  Furthermore, the recording unit 30 is provided so that recording can be performed by ejecting ink L, which is an example of a liquid, to the recording medium F sent from the transport unit 20.

  Specifically, the recording unit 30 includes a platen 34 serving as a medium support unit, a carriage 31, and a recording head 32. Among these, the platen 34 is provided so that the recording medium F can be supported from the back surface. The carriage 31 faces the platen 34 and can be moved in the width direction X with respect to the feeding direction Y of the recording medium F by the power of a carriage motor (not shown) while being guided by a first guide shaft (not shown). Is provided.

  The recording head 32 is provided on the carriage 31 so as to be able to move integrally with the carriage 31 in the width direction X. Further, the recording head 32 is configured to be able to move relative to the carriage 31 in the feed direction Y. Specifically, it is provided so that it can be moved in the feed direction Y by the power of a recording head motor (not shown) while being guided by a second guide shaft (not shown). That is, the recording head 32 is configured to be able to move in the feed direction Y and the width direction X within a range facing the platen 34. Then, it is possible to perform recording on the recording medium F by ejecting the ink L from the nozzle row 33 provided on the surface of the recording head 32 facing the platen 34.

Further, the platen 34 is provided with a drying unit 40 for evaporating 40 to 70% by weight of the ink component in the ink L adhering to the recording medium F, as will be described in detail later.
A second feed roller 43 is provided on the downstream side of the platen 34 in the feed direction. The second feed roller 43 is configured to send the recorded recording medium F to the second fixing unit 50 on the downstream side in the feed direction.

Furthermore, as will be described in detail later, the second fixing unit 50 may irradiate ultraviolet rays or an electron beam so that the remaining components in the ink L of the ink L attached to the recording medium F can be polymerized and cured. It is configured to be able to.
A third feed roller 65 is provided in the vicinity of the outlet 64 of the second fixing unit 50. The third feed roller 65 is disposed so as to be in contact with the back surface of the recording medium F, and is configured to be able to feed the recording medium F to the discharge unit 70 on the downstream side in the feeding direction.

  Further, the discharge unit 70 is provided so that the recording medium F sent from the second fixing unit 50 can be further sent to the downstream side in the feed direction and discharged to the outside of the inkjet recording apparatus 1. Specifically, the discharge unit 70 includes a fourth feed roller 71, a fifth feed roller 72, a sixth feed roller 73, a seventh feed roller 74, and a take-up roller 75. Among these, the 4th feed roller 71 and the 5th feed roller 72 are arrange | positioned so that the surface of the recording medium F may be contacted. Moreover, the 6th feed roller 73 and the 7th feed roller 74 are arrange | positioned so that a roller pair may be comprised. The recording medium F discharged by the sixth feed roller 73 and the seventh feed roller 74 is provided so as to be taken up by the take-up roller 75.

FIG. 2 is a side view illustrating an outline of a recording unit of the printer according to the present embodiment.
As shown in FIG. 2, the platen 34 is provided with a drying unit 40. Specifically, the drying unit 40 includes a first nichrome wire 42 which is an example of a heat conduction heating means (heater) 41.
Here, the “heat conduction type” means a method of transferring heat from the high temperature part to the low temperature part through the inside of the object. That is, this is a system in which heat is conducted to the recording medium side when a high-temperature object comes into contact with the recording medium. The “convection type” refers to a method of transferring heat by a fluid such as gas or liquid.

  The first nichrome wire 42 is disposed in the entire region of the platen 34 so as to be a certain distance from the upper surface of the platen 34. When energized, the first nichrome wire 42 itself generates heat, and heat can be transmitted to the back surface of the recording medium F on the platen 34 in contact with the platen 34.

  Here, since the first nichrome wire 42 is provided in the entire region of the platen 34, heat can be generated in the entire region of the platen 34. Since the platen 34 has a smooth surface without unevenness, the upper surface of the platen 34 can be in uniform contact with the recording medium F. Further, the distance from the first nichrome wire 42 to the upper surface of the platen 34 is constant. Therefore, heat can be uniformly conducted to the recording medium F on the platen 34. That is, the recording medium F can be warmed uniformly.

  Moreover, you may make it equip the drying part 40 with the warm air fan 35 as a convection type heating means. By applying warm air on the surface of the recording medium F on the platen 34, the liquid component in the ink L adhering to the recording medium F can be efficiently evaporated. The hot air fan can be replaced with an infrared lamp or both as required.

  As the recording medium F in this embodiment, a non-ink-absorbing or low-absorbing recording medium is preferably used. As such a non-ink-absorbing recording medium, for example, a plastic film coated on a substrate such as a plastic film or paper that has not been surface-treated for inkjet printing (that is, an ink-absorbing layer is not formed) is coated. And those to which a plastic film is bonded. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. Examples of the recording medium with low ink absorption include printing paper such as art paper, coated paper, and matte paper.

Here, the non-ink-absorbing and low-absorbing recording medium is a recording medium whose printing surface has a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec in the Bristow method. . This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method".

  The recording medium F sent onto the platen 34 of the recording unit 30 is temporarily stopped. Then, with the recording head 32 positioned at a position facing the downstream side in the feed direction Y on the platen 34, the carriage 31 moves in the width direction X, ink L is ejected, and recording is executed. Next, the recording head 32 moves to the upstream side in the feed direction Y with respect to the carriage 31 by the length of the nozzle row 33. Then, the carriage 31 moves in the width direction X, ink L is ejected, and recording is executed.

  Further, the recording head 32 moves further to the upstream side in the feed direction Y with respect to the carriage 31 by the length of the nozzle row 33. Then, the carriage 31 moves in the width direction X, ink L is ejected, and recording is executed. The recording head 32 moves to a position facing the upstream side in the feed direction Y of the platen 34. In this state, the carriage 31 moves in the width direction X, and the ink L is ejected and recording is performed a plurality of times. repeat. That is, scanning is performed a plurality of times.

  Thereafter, the recording medium F is sent to the downstream side of the feeding direction Y by the length of the platen 34 in the feeding direction Y, that is, the length of the feeding direction Y of the area recorded by the plurality of scans. , Pause again. Then, recording is performed on the recording medium F on the platen 34 by a plurality of scans. In other words, the recording is performed by so-called intermittent feeding.

  The ink L of the present embodiment includes at least (1) a colorant, (2) a monomer that is an organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower, (3) a polymerizable oligomer and / or polymer, and (4) light. Those containing a polymerization initiator are preferably used.

Specifically, at least (1) 0.2 to 10% by weight of pigment as a colorant
(2) Allyl glycol, N-vinylformamide as monomer, (2-methyl-2-ethyl-1,3-dioxolan-4-yl-) methyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, methoxydiethylene glycol monoacrylate , Acryloyl morpholine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, polyethylene glycol # 400 diacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, Neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, trimethylolpropant Methacrylate, trimethylolpropane modified triacrylate trimethylolpropane PO-modified triacrylate, alone or two or more kinds of organic solvents 30 to 70 wt% is selected from the group consisting of glycerol PO-modified triacrylate
(3) Polymerizable oligomer and / or polymer 10 to 50% by weight
(4) Photopolymerization initiator 3 to 10% by weight
The thing containing is mentioned.

(5) N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethylsulfoxide, ε-caprolactam, methyl lactate, ethyl lactate as a volatile organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower , Isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol isopropyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, di Propylene glycol dimethyl ether, 1,4-dioxy Down,
Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol,
n-butanol, 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octanediol, 1,2- It may contain a single organic solvent or two or more organic solvents selected from the group consisting of pentanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, and propylene glycol monobutyl ether. .

  The colorant used for chromatic and achromatic inks is a water-insoluble colorant, so-called pigment, and a preferred colorant for achromatic black ink is carbon black.

  Specifically, no. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, etc. (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U , Special Black 6, 5, 4A, 4, 250, etc. (all trade names, manufactured by Degussa), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, etc. (all trade names, Colombia) (Manufactured by Carbon Co., Ltd.), Regar 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12, etc. (all trade names, manufactured by Cabot Corporation). In addition, these are description of an example of the carbon black suitable for this invention, and this invention is not limited by these. These carbon blacks may be used alone or as a mixture of two or more.

  Preferred organic pigments for chromatic ink include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene. Pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments or azo pigments.

  Specifically, as the cyan pigment, C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, etc .; C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and 60 selected from the group consisting of 60 or more.

  Examples of magenta pigments include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, and 209, C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Violet 19.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138.

Examples of the pigment used in the orange pigment dispersion include C.I. I. Pigment Orange 36 or 43, or a mixture thereof.
Examples of the pigment used in the green pigment dispersion include C.I. I. These pigments which are CI Pigment Green 7 or 36 or a mixture thereof may be used by dispersing the resin using a dispersion resin, or by oxidizing or sulfonating the pigment surface with ozone, hypochlorous acid, fuming sulfuric acid or the like. It may be used as a self-dispersing pigment.

  Specifically, the urethane oligomer such as polyester urethane acrylate, polyether urethane acrylate, polybutadiene urethane acrylate and polyol urethane acrylate having a molecular weight in the range of 500 to 20,000 is preferable as the polymerizable oligomer added to the ink. . More specifically, U-4HA and U-15HA (both manufactured by Shin-Nakamura Chemical Co., Ltd.) are preferable.

  Specifically, the polymerizable polymer added to the ink is a dendrimer, a hyperbranched polymer, a dendrigraft polymer, a hypergraft polymer or the like that is solid at room temperature and has a molecular weight in the range of 2,000 to 50,000 (“ Dendritic polymers-the world of high functionality that multi-branched structures expand-"Keiei Aoi / Masaaki Anemoto, see NTS Corporation) are preferred.

The amount of the polymerizable oligomer and / or polymer added is preferably 10 to 50% by weight.
Specific examples of the photopolymerization initiator added to the ink include benzyldimethyl ketal, α-hydroxyalkylphenone, α-aminoalkylphenone, acylphosphine oxide, oxime ester, thioxanthone, α-dicarbonyl, anthraquinone, and the like. .

  Also, Vice 10, 30 (above, manufactured by Stauffer Chemical), Irgacure 127, 184, 500, 651, 2959, 907, 369, 379, 754, 1700, 1800, 1850, 819, OXE01, Darocur 1173, TPO, ITX Photopolymerization available under the trade names of Ciba Specialty Chemicals, Quantacure CTX (Aceto Chemical), Kayacure DETX-S (Nippon Kayaku) and ESCURE KIP150 (Lamberti) Agents can also be used.

The addition amount of the photopolymerization initiator is preferably 3 to 10% by weight.
Further, it is preferable to add a mesovolatile organic solvent and / or water having a boiling point of 100 ° C. or higher and 250 ° C. or lower to the ink.

Specifically, as a volatile organic solvent having a boiling point of 100 ° C. or more and 250 ° C. or less,
N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethylsulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol Monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol isopropyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 1,4-dioxane,
Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol,
n-butanol, 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octanediol, 1,2- Examples include pentanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, and propylene glycol monobutyl ether.

  For example, when a humectant having a high boiling point such as glycerin is added to the ink, particularly in printing on a non-absorbable recording medium of an ink such as PET media, the second fixing unit 50 uses an electron beam or ultraviolet rays. In the case of curing, the curing is insufficient and the water resistance and abrasion resistance of the printed matter cannot be obtained sufficiently.

  A colorant dispersant, a resin emulsion, or a monomer-soluble resin can be appropriately added to the ink.

  These resins need to be dispersible in monomers even when they are insoluble in monomers. When a resin emulsion is used as the thermoplastic resin, the particle diameter is not particularly limited as long as the emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 nm to 100 nm.

  Furthermore, a surfactant can be added to the ink as necessary in order to improve the stability when the ink is ejected from the ink jet recording head.

  As the surfactant, for example, a silicone-based surfactant such as polyester-modified silicone or polyether-modified silicone is preferably used, and polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane is more preferably used. Specific examples include BYK-347, 348, BYK-UV3500, 3510, 3530, 3570 (manufactured by Big Chemie Japan, Inc.), but are not limited thereto.

Furthermore, a thermal polymerization inhibitor can be added to the ink as necessary in order to improve the usability by allowing it to be stored in a warehouse at room temperature for a long period of time.
Examples of the thermal polymerization inhibitor include Irgastab UV-10 (manufactured by Ciba Specialty Chemicals), but are not limited thereto.

FIG. 3 is a side view illustrating the outline of the inside of the second fixing unit of the printer according to the present embodiment.
As shown in FIG. 3, the second fixing unit 50 includes an ultraviolet irradiation device 51. Inside the ultraviolet irradiation device 51, a first ultraviolet lamp 56, a second ultraviolet lamp 57, and a third ultraviolet lamp 58 are provided. When an LED is used, an LED with an emission peak wavelength of 395 nm is combined as a first ultraviolet lamp 56, an LED with an emission peak wavelength of 380 nm is combined with an second ultraviolet lamp 57, and an LED with an emission peak wavelength of 365 nm is combined into an third ultraviolet lamp 58. Arrange.

  As other light sources that can be used as the ultraviolet irradiation device 51, a high-pressure mercury lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, a low-pressure mercury lamp, a metal halide lamp, an ultraviolet light emitting semiconductor laser, or the like may be used. Commercially available products such as H lamp, D lamp, and V lamp available from Fusion System, etc. can also be used.

The medium support surface 53 is provided so as to support the recording medium F sent from the entrance 63 to the inside of the second fixing unit 50.
In this embodiment, the recording medium F is configured to be intermittently fed as described above. The time for which the recording medium F is temporarily stopped on the medium support surface 53 is about 5 to 50 seconds.

  During this temporary stop, the liquid in the drying unit 40 in the ink L adhered to the surface of the recording medium F by the ultraviolet rays or the electron beams emitted from the light source of the ultraviolet irradiation device 51 of the second fixing unit 50. The ink L can be fixed by polymerizing and curing the remaining components after the components are evaporated. The state of polymerization and curing can be adjusted by the intensity of ultraviolet rays, the length of time during which the ink is temporarily stopped, the oligomer component in the ink, the amount of initiator added, and the like.

  In particular, when the recording medium is a recording medium F that does not soak moisture or organic solvent in the ink component, the two-stage fixing of the ink L by the drying unit 40 and the second fixing unit 50 of this embodiment is effective. . Further, even when the recording medium is paper, the ink L can be efficiently fixed, which is effective. Further, even in a recording method in which the ink L is ejected in a larger amount than usual, the ink L can be efficiently fixed, which is effective.

  In the second fixing unit 50, when the polymerization and curing of the residual ink component is insufficient, the ink adheres to the parts of the fourth feed roller 71 to the seventh feed roller 74 in the discharge unit 70, and further, transfer from there, Dirt may adhere to the recording medium itself.

  Hereinafter, the present invention will be described in more detail with reference to results of printing evaluation using actual machines, but the scope of the present invention is not limited thereto.

(ink)
[Preparation of ink]
First, the pigment dispersion was prepared by the method shown below.
As a coloring agent, C.I. I. 20 parts of Pigment Blue 15: 3, 5 parts of DISCOL (registered trademark) N-509 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a dispersant, and 75 parts of allyl glycol (manufactured by Nippon Emulsifier Co., Ltd.) as a monomer are mixed, and zirconia Dispersion treatment was performed for 5 hours using a sand mill (manufactured by Yaskawa Seisakusho) together with beads (diameter 1.5 mm).

Thereafter, the zirconia beads were removed with a separator to obtain a cyan pigment dispersion.
In the same manner, C.I. I. Magenta pigment dispersion using CI Pigment Red 122, C.I. I. A yellow pigment dispersion using Pigment Yellow 180 and a black pigment dispersion using carbon black as a colorant were prepared.

Next, an ink having the following composition was prepared using each of the color pigment dispersions.
(Cyan ink composition 1)
C. as a colorant I. Pigment Blue 15: 3 4% by weight
Discol N-509 1% by weight as a colorant dispersant
10% by weight of N-vinylformamide as monomer
20% by weight of U-15HA as an oligomer
Irgacure 127 3% by weight as photopolymerization initiator
Irgacure 819 2% by weight as a photoinitiator
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
Allyl glycol as monomer 59.6% by weight
The cyan ink was adjusted.

(Magenta ink composition 2)
C. as a colorant I. Pigment Red 122 5% by weight
DISCOL as a dispersant for colorant N-509 1.25% by weight
30% by weight of allyl glycol as monomer
50% by weight of U-15HA as an oligomer
Irgacure 127 2% by weight as a photoinitiator
Irgacure 819 1% by weight as a photoinitiator
7.35% by weight of 2-pyrrolidone as a medium volatile organic solvent
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
3% pure water
The magenta ink was adjusted.

(Yellow ink composition 3)
C. as a colorant I. Pigment Yellow 180 10% by weight
DISCOL as a dispersant for colorant N-509 2.5% by weight
10% by weight of 2-pyrrolidone as a medium volatile organic solvent
10% by weight of U-15HA as oligomer
Irgacure 127 3% by weight as photopolymerization initiator
Irgacure 819 2% by weight as a photoinitiator
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
Allyl glycol as monomer 62.1% by weight
The yellow ink was adjusted.

(Black ink composition 4)
6% by weight of carbon black as a colorant
DISOL as a colorant dispersant N-509 1.5 wt%
20% by weight of N-methylpyrrolidone as a medium volatile organic solvent
20% by weight of U-15HA as an oligomer
Irgacure 127 7% by weight as photopolymerization initiator
Irgacure 819 3% by weight as photopolymerization initiator
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
Allyl glycol as monomer 42.1% by weight
The black ink was adjusted.

[Printing evaluation]
As a recording medium,
1) PVC film: ViewCAL (manufactured by Sakurai Co., Ltd., model number VC900B)
2) Transparent PET film: Super Kimoart (Kimotosha, SP2)
3) PP film: Cold LF (manufactured by Ramie C, model number PPG-20S)
Was evaluated using a printer having the configuration shown in FIGS.

As a recording head, a type mounted on an ink jet printer PX-B500 (trade name, manufactured by Seiko Epson Corporation) is used, and the recording head is filled with the ink compositions 1 to 4 described above, and a discharge ink weight of 30 ng / dot (nanogram / dot), 360 dpi (dot / inch) resolution,
I. Vertical and horizontal ruled lines formed with one black dot
II. Cyan, magenta, yellow printing duty 100% solid
III. A ruled line of each color of cyan, magenta, and black formed by 3 dots was printed on a solid of 100% yellow printing duty.

  By changing the temperature of the heater 41 attached and the temperature and air volume of the hot air fan 35 in the platen 34 as a drying unit during printing, the evaporation amount of the ink component in the drying unit is 30% of the test 1 and the test 2 of the test 2 Control was performed so that the setting was 40%, 50% of Test 3, 60% of Test 4, 70% of Test 5, and 80% of Test 6.

Next, after printing, the recording medium is sent to the ultraviolet irradiation device 51 of the second fixing unit 50, and a Fusion System D lamp is used as the first ultraviolet lamp 56, the second ultraviolet lamp 57, and the third ultraviolet lamp 58, Polymerization curing was performed at an irradiation intensity of 100 mW / cm ^2, respectively.
The irradiation time was 10 seconds for Test 1 and Test 2, and 5 seconds for Test 3, Test 4, Test 5 and Test 6.

The print evaluation results are recorded by visual inspection by five subjects.
In evaluation I, A: no beading phenomenon, B: occurrence of beading In evaluation II, A: no occurrence of betamura, B: occurrence of betamura In evaluation III, A: no color bleeding phenomenon, B: occurrence of color bleeding Judgment was made and a majority decision was adopted. The results are shown as tests 1 to 6 in FIG.

Next, magenta ink composition 5 was prepared by replacing 2-pyrrolidone as a medium volatile organic solvent in magenta ink composition 2 with glycerin as a low volatile organic solvent.
Further, the black ink composition 6 was prepared by replacing N-methylpyrrolidone as the medium volatile organic solvent in the black ink composition 4 with glycerin as the low volatile organic solvent.
In the printing evaluation described above, Test 7 was performed in the same manner as Tests 1 to 6 except that magenta ink composition 2 was replaced with magenta ink composition 5 and black ink composition 4 was replaced with black ink composition 6. The result is shown in FIG.

  Further, as a recording medium, a PVC film: ViewCAL (manufactured by Sakurai Co., Ltd., model number VC900B), the printer having the configuration shown in FIGS. 1 to 3 described above is used, and an ink jet printer PX-5600 (trade name, Seiko Epson) is used as the recording head. The above ink compositions 1 to 4 and the following ink compositions 7 to 9 are filled in the recording head, and the discharge ink weight is 5 ng / dot (nanogram / dot), 1 , 440 dpi × 1, 440 dpi resolution, 4 ng ejection amount, and 8 pass printing evaluation.

(Light cyan ink composition 7)
C. as a colorant I. Pigment Blue 15: 3 0.5% by weight
DISOL N-509 0.125% by weight as a colorant dispersant
10% by weight of N-vinylformamide as monomer
50% by weight of U-15HA as an oligomer
Irgacure 127 3% by weight as photopolymerization initiator
Irgacure 819 2% by weight as a photoinitiator
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
Allyl glycol as monomer 33.975% by weight
The light cyan ink was adjusted.

(Light magenta ink composition 8)
C. as a colorant I. Pigment Red 122 0.5% by weight
DISOL N-509 0.125% by weight as a colorant dispersant
30% by weight of allyl glycol as monomer
50% by weight of U-15HA as an oligomer
Irgacure 127 2% by weight as a photoinitiator
Irgacure 819 1% by weight as a photoinitiator
7.35% by weight of 2-pyrrolidone as a medium volatile organic solvent
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
Pure water 8.625% by weight
The light magenta ink was adjusted.

(Light black ink composition 9)
Carbon black as a colorant 0.2% by weight
DISCOL as a colorant dispersant N-509 0.05% by weight
4.35% by weight of N-methylpyrrolidone as medium volatile organic solvent
20% by weight of U-15HA as an oligomer
Irgacure 127 2% by weight as a photoinitiator
Irgacure 819 3% by weight as photopolymerization initiator
Irgastab UV-10 0.2% by weight as thermal polymerization inhibitor
BYK-UV3500 0.2% by weight as a silicone surfactant
70% by weight of allyl glycol as a monomer
The light black ink was adjusted.

  In the above test, a gradation pattern of 0% to 100% duty of yellow, magenta, cyan, red, green, blue and black was printed. In the platen 34 as the drying unit, the temperature of the heater 41 and the temperature and the air volume of the hot air fan 35 were controlled in the platen 34 as the drying unit so that the evaporation amount of the ink component in the drying unit was in the range of 40 to 70% in the print pattern. .

Next, after printing, the recording medium is sent to the ultraviolet irradiation device 51 of the second fixing unit 50, and a Fusion System D lamp is used as the first ultraviolet lamp 56, the second ultraviolet lamp 57, and the third ultraviolet lamp 58, Polymerization curing was performed at an irradiation intensity of 100 mW / cm ^2, respectively.
The irradiation time was 10 seconds.
As a result, no occurrence of aggregation unevenness was observed, and a good gradation could be printed. Moreover, the fixability of the printed matter was also good.

  As is apparent from the above results, 40% by weight or more of the ink adhering to the recording medium is evaporated in the first drying section, and the second fixing provided downstream of the first drying section in the feeding direction of the recording medium. In addition, by polymerizing and curing the ink residual components in the printing section, it is possible to perform high-speed and high-quality inkjet recording on a recording medium with low ink absorption performance, such as glossy fine-coated paper used as printing paper. It was.

  Furthermore, when 40% by weight or more of the ink adhering to the recording medium is evaporated in the first drying unit, high-speed and high-quality images can be obtained even in non-ink-absorbing recording media such as PVC, PET, and PP films. Inkjet recording was possible. On the contrary, when the evaporation amount in the first drying portion is smaller than those, beading or betting due to ink gathering phenomenon occurs on the surface of the recording medium, or color ink that is insufficiently dried on the recording medium Color bleed may occur due to the mixing of each other.

  Further, when an amount larger than 70% by weight of the ink adhering to the recording medium is evaporated in the first drying unit, it contributes to printing in a non-absorbing recording medium such as PET media. Since the amount of ink is reduced, the width of the ruled line in the scanning direction of the head is narrowed. As a result, white stripes occur at a solid portion of 100% duty, which is perceived by the subjects like a sticky and high-quality inkjet recording. It was difficult to do.

  As apparent from the printing result of Test 7 shown in FIG. 5, since the ink composition contains glycerin, which is a low volatility humectant having a boiling point of 290 ° C., ink non-absorbing properties such as PVC, PET, and PP films are included. In the recording medium, although an appropriate amount of ink is evaporated in the first drying section, it takes a relatively long time to reach the appropriate amount. Insufficient drying caused beading and betting due to the gathering phenomenon, making it difficult to perform high-quality inkjet recording.

  That is, according to the ink jet recording apparatus and the recording method using the same according to the present invention, it was possible to perform high-quality recording at high speed on a non-ink-absorbing recording medium. In this case, compared with a recording apparatus provided with a heating means for promoting drying of ink at one location in the vicinity of the recording head as proposed in the past and a recording method using the same, it is more suitable for ink evaporation. Since heat is efficiently applied to the recording material and the ink polymerization and curing is efficiently performed by ultraviolet rays or electron beams, the effect of suppressing the energy required for drying the ink as a whole can be obtained.

  DESCRIPTION OF SYMBOLS 1 Inkjet recording device, 10 feeding part, 11 roll medium holder, 20 conveyance part, 21 1st feeding roller, 30 recording part, 31 carriage, 32 recording head, 33 nozzle row, 34 platen, 35 hot air fan, 40 drying Part 41 heat conduction heating means (heater) 42 first nichrome wire 43 second feed roller 50 second fixing part 51 ultraviolet irradiation device 53 medium support surface 56 first ultraviolet lamp 57 second ultraviolet ray Lamp, 58 3rd UV lamp, 63 entrance, 64 exit, 65 3rd feed roller, 70 discharge part, 71 4th feed roller, 72 5th feed roller, 73 6th feed roller, 74 7th feed roller, 75 rolls Take-off roller, 90 fixing section, F recording medium, L ink, X width direction, Y feed direction.

Claims (5)

A recording head for ejecting ink to the surface of the recording medium;
A medium support portion facing the recording head and supporting the recording medium from the back surface;
A drying unit as a first fixing unit that evaporates the liquid component of the ink ejected and adhered to the recording medium from the recording head;
A recording method performed using an inkjet recording system including a second fixing unit on the downstream side in the transport direction of the recording medium from the drying unit,
The ink is at least
(1) Colorant (2) Monomer which is an organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower (3) A polymerizable oligomer and / or polymer other than the monomer (2) (4) Initiating photopolymerization Agent (5) A volatile organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower, which is N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethylsulfoxide, ε-caprolactam, methyl lactate, Ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene Recall isopropyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 1,4-dioxane, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butane Diol, hexylene glycol, n-butanol, 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octane Diol, 1,2-pentanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene Recall monopentyl ether, alone or two or more kinds of organic solvent selected from the group consisting of propylene glycol monobutyl ether as a content in the ink from 4.35 to 20 wt%
Including no low volatile organic solvent having a boiling point of more than 250 ° C.,
The second fixing unit is an irradiation device that irradiates the recording medium with ultraviolet rays or an electron beam;
Ejecting ink onto the surface of the recording medium by the recording head;
Evaporating 40 to 70% by weight of the ink liquid component of the ink attached to the recording medium by the drying unit;
Residue after the liquid component of the ink is evaporated by irradiating the recording medium on which the liquid component has evaporated in the drying unit with the irradiation device as the second fixing unit by irradiating the recording medium with ultraviolet rays or an electron beam. And a step of polymerizing and curing the components. The ink, as each component,
(1) Pigment as colorant 0.2 to 10% by weight
(2) As a monomer which is an organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower, allyl glycol, N-vinylformamide, (2-methyl-2-ethyl-1,3-dioxolan-4-yl-) methyl acrylate, Phenoxyethyl acrylate, isobornyl acrylate, methoxydiethylene glycol monoacrylate, acryloylmorpholine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, polyethylene glycol # 400 diacrylate, tetraethylene glycol Dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimeta Lilo alkoxy propane, trimethylolpropane trimethacrylate, trimethylolpropane PO-modified triacrylate, alone or two or more kinds of organic solvents 30 to 70 wt% is selected from the group consisting of glycerol PO-modified triacrylate
(3) Polymerizable oligomer and / or polymer other than the monomer of (2)
10-50% by weight
(4) Photopolymerization initiator 3 to 10% by weight
The recording method according to claim 1 , comprising: The recording method according to claim 1 or 2, wherein the ink further contains 8.625% by weight or more of water in the ink . The ink contains the components,
(1) Colorant 0.2 to 10% by weight
(2) 30 to 70% by weight of a monomer which is an organic solvent having a boiling point of 100 ° C. or higher and 250 ° C. or lower
(3) Polymerizable oligomer and / or polymer other than the monomer of (2)
10-50% by weight
(4) Photopolymerization initiator 3 to 10% by weight
Containing, recording method according to any one of claims 1 to 3.   An ink jet recording system for performing recording by the recording method according to claim 1.

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