JP2018202870A - Recording method - Google Patents

Abstract

To provide inkjet recording devices and recording methods that perform high-speed inkjet recording on a recording target medium with significantly low ink absorptivity.SOLUTION: The method includes a first drying step and a second drying step. In the first drying step, with respect to a recording target medium (F) with ink sprayed thereto, 50-85 wt.% of the ink is evaporated. The second drying step is performed on the downstream side in the feeding direction of the recording target medium than the first drying step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a recording method for performing high-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 view of such circumstances, and provides a recording method for performing inkjet recording at high speed on a recording medium having a remarkably low ink absorption capability.

  In order to achieve the above object, according to a preferred aspect of the present invention, the medium is opposed to the recording head that ejects ink to the surface of the recording medium, and the medium supporting unit that supports the recording medium from the back surface is A first drying step for evaporating 50 to 85% by weight of the ink adhering to the recording medium with respect to the recording medium on which ink is ejected from a recording head; and the recording medium that has undergone the first drying step. And a second drying step of drying on the downstream side in the feed direction of the recording medium from the medium support portion.

Furthermore, according to a preferred aspect of the present invention, the first drying step evaporates 60 to 80% by weight of the ink adhering to the recording medium with respect to the recording medium on which the ink is ejected from the recording head. It is characterized by that.
According to a preferred aspect of the present invention, the first drying step is a heat conduction type and / or a convection type.
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 (jetting medium). The “convection type” refers to a method of transferring heat by a fluid such as gas or liquid.

  After the ink ejected from the recording head adheres to the recording medium, it is heated in the first drying section, and 50% by weight, preferably 60% by weight or more of the ink component adhering to the recording medium evaporates. If the number is less than that, line width non-uniformity (beading) occurs when a ruled line is printed, color unevenness or mixing of different colors (color bleed) occurs when solid printing is performed.

  Further, after the ink ejected from the recording head adheres to the recording medium, it is heated in the first drying section, and the ink component adhering to the recording medium does not evaporate more than 85% by weight, preferably more than 80% by weight. . If it is evaporated more than that, the adhering dot diameter of ink droplets cannot be obtained sufficiently on the recording medium, and when the ruled lines are printed, the lines are not connected, or unevenness occurs in the case of solid printing . In addition, since the adhered dots of ink droplets become thick, the rub resistance may decrease.

  The second drying step is preferably a convection type.

  The recording medium is preferably a film material.

  The ink comprises at least (1) a colorant, (2) a resin, (3) a water-soluble resin solvent, (4) a volatile moisturizing agent, (5) a water-soluble penetrating solvent, (6) a surfactant, (7 It is desirable that the water-soluble resin solvent, the intermediate volatile humectant and the water-soluble penetrant are all organic solvents having a boiling point of 100 ° C. or higher and 250 ° C. or lower.

As the recording medium used in the present invention, a non-ink-absorbing or low-absorbing recording medium is preferably used. As such a recording medium, as a non-ink-absorbing recording medium, for example, a substrate such as a plastic film or paper that is not surface-treated for inkjet printing (that is, has no ink absorption layer formed) Examples include those coated with plastic or those having a plastic film adhered thereto. 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".

Furthermore, as the ink used in the present invention, at least,
(1) Pigment as colorant 0.5 to 10% by weight
(2) Single or two or more kinds of resins selected from the group consisting of a colorant dispersant, a resin emulsion or a water-soluble resin 0.5 to 10% by weight
(3) N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethylsulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl as a water-soluble resin solvent Ether, ethylene glycol dimethyl 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, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol Dimethyl ether, 2-10% by weight alone or two or more kinds of organic solvent selected from the group consisting of 1,4-dioxane
(4) From the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol, and 2,3-butanediol as medium volatile humectants Single or two or more organic solvents selected 2 to 15% by weight
(5) n-butanol, 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1, Single or two or more kinds of organic compounds selected from the group consisting of 3-octanediol, 1,2-pentanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, propylene glycol monobutyl ether 1-8% by weight of solvent
(6) A single or two or more kinds of surfactants selected from the group consisting of acetylene glycol surfactants or silicone surfactants 0.5 to 2% by weight
(7) It contains 50 to 80% by weight of water.

The colorant used in the chromatic and achromatic inks of the present invention is a water-insoluble colorant, which is a so-called pigment, and a preferred colorant for an 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.

  The dispersants or resin emulsions or water-soluble resins for the ink colorant used in the present invention are preferably those listed below.

  These resins are preferably a polymer having both a hydrophilic portion and a hydrophobic portion, since water dispersibility is required even when water-insoluble. 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.

  As the thermoplastic resin, a resin component similar to a dispersant resin or a resin emulsion conventionally used in ink compositions for ink jet recording can be used. Specific examples of the thermoplastic resin include acrylic polymers such as polyacrylic acid esters or copolymers thereof, polymethacrylic acid esters or copolymers thereof, polyacrylonitrile or copolymers thereof, polycyanoacrylates, poly Acrylamide, polyacrylic acid, or polymethacrylic acid; polyolefin polymers such as polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene or copolymers thereof, petroleum resins, coumarone-indene resins, or terpene resins; vinyl acetate Vinyl alcohol polymers such as polyvinyl acetate or copolymers thereof, polyvinyl alcohol, polyvinyl acetal, or polyvinyl ether; halogen-containing polymers such as polyvinyl chloride or copolymers thereof. Polymers, polyvinylidene chloride, fluororesins, or fluororubbers; nitrogen-containing vinyl polymers such as polyvinyl carbazole, polyvinyl pyrrolidone or copolymers thereof, polyvinyl pyridine, or polyvinyl imidazoles; diene polymers such as polybutadiene or the like A copolymer, polychloroprene, or polyisoprene (butyl rubber); or other ring-opening polymerization resin, condensation polymerization resin, natural polymer resin, or the like can be used.

  Furthermore, Hitech E-7025P, Hitech E-2213, Hitech E-9460, Hitech E-9015, Hitech E-4A, Hitech E-5403P, Hitech E-8237 (all trade names, manufactured by Toho Chemical Co., Ltd.), AQUACER 507 , AQUACER 515, AQUACER 840 (all trade names, manufactured by Big Chemie Japan Co., Ltd.) and the like.

  When the thermoplastic resin is obtained in the form of an emulsion, it can be prepared by mixing the resin particles with water, optionally with a surfactant. For example, an emulsion of an acrylic resin or a styrene-acrylic acid copolymer resin is composed of a (meth) acrylic ester resin or a styrene- (meth) acrylic ester resin, and optionally a (meth) acrylic resin, It can be obtained by mixing the active agent with water. The mixing ratio of the resin component and the surfactant is usually preferably about 50: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when it exceeds the above range, the water resistance of the ink tends to decrease or the adhesion tends to deteriorate. Therefore, it is not preferable.

The surfactant used here is not particularly limited, but preferred examples include anionic surfactants (for example, sodium dodecyl benzan sulfonate, sodium laurylate, ammonium salt of polyoxyethylene alkyl ether sulfate, etc.), nonions Surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl amines, polyoxyethylene alkyl amides, etc. These can be used as a mixture of two or more.
An emulsion of a thermoplastic resin can also be obtained by emulsion polymerization of the above resin component monomers in water in the presence of a polymerization catalyst and an emulsifier. A polymerization initiator, an emulsifier, and a molecular weight modifier used in the emulsion polymerization can be used according to a conventional method.

As the polymerization initiator, those used for normal radical polymerization are used, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, Examples include peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide, and the like. When the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable. Examples of the emulsifier include sodium lauryl sulfate, those generally used as an anionic surfactant, nonionic surfactant or amphoteric surfactant, and mixtures thereof. These can be used in combination of two or more.
The ratio of the resin and water as the dispersed phase component is preferably 60 to 400 parts by weight, more preferably 100 to 200 parts by weight of water with respect to 100 parts by weight of the resin.

  When a resin emulsion is used as the thermoplastic resin, a known resin emulsion can be used. For example, the resin emulsions described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, or JP-A-4-18462 are used. It can be used as it is. Commercially available resin emulsions can also be used. For example, Microgel E-1002, E-5002 (styrene-acrylic resin emulsion; manufactured by Nippon Paint Co., Ltd.), Boncoat (registered trademark) 4001 (acrylic resin) Emulsion; Dainippon Ink and Chemicals Co., Ltd.), Boncoat 5454 (styrene-acrylic resin emulsion; Dainippon Ink and Chemicals Co., Ltd.), SAE1014 (styrene-acrylic resin emulsion; manufactured by Nippon Zeon Co., Ltd.), or Cybinol (Registered trademark) SK-200 (acrylic resin emulsion; manufactured by Seiden Chemical Co., Ltd.) can be used. The thermoplastic resin may be mixed as a fine particle powder with other components in the aqueous ink, but after the resin fine particles are dispersed in an aqueous medium to form a resin emulsion, the thermoplastic resin is mixed with the other components of the aqueous ink. It is preferable. From the viewpoints of long-term storage stability and ejection stability of the water-based ink, the particle diameter of the resin fine particles preferred in the present invention is in the range of 5 to 400 nm, more preferably in the range of 50 to 200 nm.

Examples of the water-soluble resin include water-insoluble polymers such as polyethylene glycol, polyvinyl pyrrolidone, polyvinyl alcohol, and polyvinyl acetal.
The resin is preferably contained in a range of 0.5 to 10.0% by weight in terms of solid content with respect to the total amount of the water-based ink. If the resin component is too small, the ink film formed on the plastic surface becomes thin and the adhesion to the plastic surface may be insufficient. If the resin component is too much, the dispersion of the resin may become unstable during storage of the ink composition, or the resin component may be agglomerated and solidified due to slight evaporation of water, and a uniform film may not be formed.

Specific examples of preferable water-soluble penetrating solvents and surfactants added to the ink used in the present invention include the following.
Examples of water-soluble penetrating solvents include 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 monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, propylene glycol monobutyl ether, and the content thereof is 1 with respect to the total amount of the ink composition. -8 wt% is preferred.

  Examples of the acetylene glycol surfactant used in the ink of the present invention include Surfynol (registered trademark) 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, SE, SE-F, 61. 82, DF-110D (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol (registered trademark) E00, E00P (all trade names, manufactured by Kawaken Fine Chemical Co., Ltd.) and the like are preferable.

  As the silicone surfactant used in the ink of the present invention, a polysiloxane compound is preferably used, and examples thereof include polyether-modified organosiloxane. For example, silicon additives BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 and the like are preferable from Big Chemie Japan Co., Ltd.

Particularly preferred is a combination comprising a silicone surfactant and an acetylene glycol surfactant having an HLB value of 6 or less at the same time.
Further, the content of the surfactant is preferably 0.5 to 2% by weight.

  It is preferable that the surface tension of the water-based ink is used in the range of 23.0 mN / m to 40.0 mN / m, more preferably 25.0 mN / m to 35. The range is 0 mN / m.

  The water-soluble resin solvent used in the ink of the present invention is selected from water-soluble solvents that are compatible with the resin emulsion that is simultaneously added to the resin ink. There are optimum combinations depending on the resin to be used. Specifically, pyrrolidones such as N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, ε-caprolactam, methyl lactate, ethyl lactate , Isopropyl lactate, butyl lactate, ethylene glycol monomethyl ether, ethylene glycol dimethyl 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, propylene glycol dimethyl ether , Dipropylene glycol Monomethyl ether, dipropylene glycol dimethyl ether, 1,4-dioxane and the like are preferable. In particular, pyrrolidones are particularly preferable in terms of sufficient drying speed and promotion of film formation.

  The water-soluble resin solvent added to the ink used in the present invention may be added to chromatic and / or achromatic inks and resin inks containing no colorant, and is effective for further strengthening the film.

  Specific examples of water-soluble resin solvents include N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, and ethylene glycol. Monomethyl ether, ethylene glycol dimethyl 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, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol Call dimethyl ether 1,4-dioxane.

The addition amount of the water-soluble resin solvent is preferably 2 to 10% by weight.
The medium volatile moisturizing agent used in the ink of the present invention is preferably one that does not remain in the printed film when dried. Diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, Examples include hexylene glycol and 2,3-butanediol.

  For example, when a humectant having a low boiling point such as glycerin is added to the ink, heating by a very large energy in the second drying section, particularly in printing on a non-absorbable recording medium of ink such as PET media. Therefore, there arises a problem that the apparatus becomes large and the power consumption during operation of the recording apparatus increases. Insufficient drying in the second drying section may result in insufficient water resistance and rubbing resistance of the printed matter, or printing stains may occur in the recording medium feed driving section in the recording apparatus. Furthermore, in order to obtain high-quality printing in the present invention, it is necessary to evaporate the ink in the first drying section in an amount of 50 to 85% by weight, more preferably 60 to 80% by weight. Condition control becomes very difficult and places a heavy load on the device.

  Water is the main solvent of the ink used in the present invention. Preferred water is pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water for the purpose of reducing ionic impurities as much as possible. Water or ultrapure water can be used. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because it can prevent generation of mold and bacteria when the pigment dispersion and aqueous ink using the same are stored for a long period of time. .

Further, as necessary, antiseptics, fungicides, pH adjusters, antioxidants, metal trapping agents and the like can be mentioned.
Examples of preservatives and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN from ICI) and the like.
Examples of the pH adjuster include inorganic alkalis such as sodium hydroxide and potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, morpholine, potassium dihydrogen phosphate or disodium hydrogen phosphate.
Examples of the metal trapping agent include disodium ethylenediaminetetraacetate.

1 is a side view showing an outline of an entire inkjet recording apparatus according to the present invention. FIG. 2 is a side view illustrating an outline of a recording unit of a printer as an example of the ink jet recording apparatus according to the invention. FIG. 3 is a side view illustrating an outline of a second drying unit of a printer as an example of the ink jet recording apparatus according to the invention. The table | surface which shows the result of the tests 1-7 based on this invention. The table | surface which shows the result of the test 8 which concerns on this invention.

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 invention.

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 drying device 90, and a discharge unit 70.
Among these, the drying apparatus 90 has the 1st drying part 50 which performs the 1st drying process mentioned later, and the 2nd drying part 40 which performs a 2nd drying process.
Further, the feeding unit 10 is provided so as to feed a recording medium F in a roll shape, which is an example of the ejection target medium and the recording medium, 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 as to perform recording by discharging ink L (see FIG. 2), which is an example of a liquid, to the recording medium F sent from the transport unit 20. Yes.
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 first drying unit 40 that evaporates 40 to 80% by weight of the ink component in the ink L ejected onto 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 drying unit 50 on the downstream side in the feed direction.

Furthermore, as will be described in detail later, the second drying unit 50 is configured to be able to further evaporate a part of the remaining components in the ink L ejected onto the recording medium F.
A third feed roller 65 is provided in the vicinity of the outlet 64 of the second drying 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.

  Furthermore, the discharge unit 70 is provided so that the recording medium F sent from the second drying unit 50 can be further sent to the downstream side in the feed direction 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.

The first drying process will be described.
FIG. 2 is a side view showing an outline of a recording unit 30 of a printer as an example of an ink jet recording apparatus according to the present invention.
As shown in FIG. 2, the platen 34 is provided with a first drying unit 40. Specifically, the first drying unit 40 includes a first nichrome wire 42 which is an example of the heat conduction heating means 41. 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.

The recording medium F of this embodiment is a plastic film.
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 of 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 by the length of the nozzle row 33 toward the upstream side in the feed direction with respect to the carriage 31. 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 by the length of the nozzle row 33 toward the upstream side in the feed direction with respect to the carriage 31. Then, the carriage 31 moves in the width direction X, ink L is ejected, and recording is executed. This is repeated a plurality of times until the recording head 32 moves to a position facing the upstream side of the feeding direction of the platen 34, and the carriage 31 moves in the width direction X in this state until ink L is ejected and recording is executed. . That is, scanning is performed a plurality of times.

Thereafter, the recording medium F is sent to the downstream side in the feed direction by the length in the feed direction Y of the platen 34, that is, the length in the feed direction Y of the area recorded by the plurality of scans. Pause. 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.
Here, the 1st drying part 40 is not a convection type but a heat conduction type. Therefore, there is no possibility that warm air is blown directly onto the nozzle row 33 of the recording head 32. As a result, there is no possibility of affecting the state of the nozzle row 33 of the recording head 32. Specifically, when the ink L in the nozzles is dried, the viscosity increases, and there is no possibility of causing ejection failure. Further, the first drying unit 40 is at a lower temperature than the second drying unit 50. The low temperature level is such that there is no possibility of affecting the state of the nozzle row 33 of the recording head 32.

A 2nd drying process is demonstrated.
FIG. 3 is a side view showing an outline of the inside of the second drying unit of the printer as an example of the ink jet recording apparatus according to the present invention.
As shown in FIG. 3, the second drying unit 50 includes a drying furnace 52 as an example of the convection heating unit 51. Inside the drying furnace 52, there are a first partition plate 59, a second partition plate 60, a first passage 61, a second passage 62, a medium support surface 53, a second nichrome wire 54, a cross flow fan 55, a first An axial fan 56, a second axial fan 57, and a third axial fan 58 are provided.
Among these, the first partition plate 59 and the second partition plate 60 are disposed so as to partition the spaces A, B, and C. In addition, the first opening 61 is provided so that air flows between the space A and the space C. Furthermore, the second passage 62 is provided so that air flows between the space A and the space B. 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 drying furnace 52.

  Furthermore, the second nichrome wire 54 is arranged such that the second nichrome wire 54 itself generates heat when energized, and can heat the air in the space A partitioned by the first partition plate 59. ing. Specifically, the air that has entered the space A from the first opening 61 is heated. Further, the cross flow fan 55 generates a flow for sending air heated by the second nichrome wire 54 from the space A to the space B through the second passage 62.

Here, the cross-flow fan has a fan having a relatively small diameter and a long side and sucks air from one radial direction of the impeller and blows air from the opposite radial direction. Also called a cross-flow fan.
The first axial fan 56 to the third axial fan 58 are provided on the second partition plate 60, and the hot air in the space B is substantially perpendicular to the surface of the recording medium F on the medium support surface 53 of the space C. It is provided to hit. The warm air blown to the recording medium F passes through the side of the medium support surface 53 and flows to the space A through the first passage 61.

In the present embodiment, the temperature of the warm air blown by the first axial fan 56 to the third axial fan 58 on the medium support surface 53 is 60 to 100 degrees. That is, the temperature is higher than that of the first drying unit 40. The ink L is dried by evaporating an organic solvent that is less likely to evaporate than moisture at a high temperature and relatively strong wind power.
At this time, since the viscosity of the ink L on the surface of the recording medium F has already increased as described above, there is almost no possibility that the ink L is disturbed even if a strong wind is blown. Specifically, there is no possibility that the ink L moves on the surface of the recording medium F by being blown strongly. Then, by blowing a strong wind at a high temperature, the organic solvent which is difficult to evaporate can be efficiently evaporated in a short time.

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 the temporary stop, the evaporation of the ink L ejected onto the surface of the recording medium F can be further promoted and dried. The drying state can be adjusted by the temperature of the hot air, the length of time during which it is temporarily stopped, the organic solvent component in the ink, and the like.
In particular, when the recording medium is a recording medium F that does not soak water or organic solvent in the ink component, the two-stage drying by the first drying unit 40 and the second drying unit 50 of this embodiment is effective. Even when the recording medium is paper, the ink L can be efficiently dried, which is effective. Furthermore, it is also effective in the case of a recording method in which the ink L is ejected in a larger amount than usual because the ink L can be efficiently dried.

The cross flow fan 55 and the first partition plate 59 are provided at positions shifted from the recording medium F in the width direction X so as not to interfere with the recording medium F that enters from the entrance 63 and exits from the exit 64. It shall be.
In the second drying unit, the evaporation of the ink component cannot be promoted, and when the drying 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 from there Due to the transfer, the recorded matter itself may be soiled.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples.

[Example 1]
(ink)
[Preparation of ink]
(Adjustment of cyan ink composition 1)
As a colorant, C.I. I. Pigment Blue 15: 3 4% by weight
As a colorant dispersion resin, acrylic acid-acrylic acid ester copolymer (molecular weight 25000, glass transition temperature 80 ° C., acid value 180) 2% by weight
As a resin emulsion, styrene-acrylic acid copolymer (molecular weight 50000, acid value 130, average particle diameter 75 nm) 2% by weight
1,2-hexanediol 5% by weight as water-soluble penetrating solvent
Surfynol DF-110D (trade name, manufactured by Nissin Chemical Industry Co., Ltd.) 0.2% by weight as an acetylene glycol surfactant
BYK-348 (trade name, polyether-modified organosiloxane manufactured by Big Chemie Japan Co., Ltd.) 0.6% by weight as a silicone-based surfactant
As a water-soluble resin solvent, 2-pyrrolidone 5% by weight
10% by weight propylene glycol as a medium volatile moisturizer
Cyan ink was adjusted with the remaining amount of pure water.

(Adjustment of magenta ink composition 2 and yellow ink composition 3)
Composition of colorant for chromatic ink 1 2: C.I. I. Pigment Red 122, 5% by weight, composition 3: C.I. I. Pigment Yellow 180 was replaced with 6% by weight, and magenta ink and yellow ink were respectively adjusted.

(Adjustment of black ink composition 4)
As a colorant, carbon black MA77 (trade name, 6% by weight manufactured by Mitsubishi Chemical Corporation)
As a colorant dispersion resin, acrylic acid-acrylic acid ester copolymer (molecular weight 25000, glass transition temperature 80 ° C., acid value 180) 2% by weight
Styrene-acrylic acid copolymer (molecular weight 50000, acid value 130, average particle diameter 75 nm) as resin emulsion 2% by weight
1,2-hexanediol 5% by weight as water-soluble penetrating solvent
Surfynol DF-110D (trade name, manufactured by Nissin Chemical Industry Co., Ltd.) 0.2% by weight as an acetylene glycol surfactant
BYK-348 (trade name, polyether-modified organosiloxane manufactured by Big Chemie Japan Co., Ltd.) 0.4% by weight as a silicone-based surfactant
As a water-soluble resin solvent, 2-pyrrolidone 5% by weight
10% by weight propylene glycol as a medium volatile moisturizer
The black ink was adjusted with the remaining amount of pure water.
The surface tensions of the inks having the compositions 1 to 4 were all 26 mN / m.

[Printing evaluation]
As a recording medium, OK top coat of glossy fine coated paper used as so-called printing paper + (trade name, manufactured by Oji Paper Co., Ltd.), PET media cold laminate film PG-50L (trade name, Ramie Corporation) And PPC paper P (64 g / m ² , manufactured by Fuji Xerox Co., Ltd.), which is widely used as copy paper in general offices, was subjected to print evaluation using a printer having the configuration shown in FIGS.

As the 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 above ink compositions 1 to 4, and the discharge ink weight is 30 ng / dot. (Nanogram / dot) With resolution of 360 dpi (dot / inch) (1) Vertical and horizontal ruled lines formed with one black dot (2) Printing of cyan, magenta and yellow colors 100% solid (3) Yellow printing A ruled line of each color of cyan, magenta and black formed by 3 dots was printed on a solid of 100% duty.

  Next, in the platen 34 as the first drying unit, the temperature of the attached heater was changed to control the evaporation amount of the ink component in the first drying unit. After printing, the recording medium was sent to a drying furnace 52 as a second drying section, and warm air was applied to the recording medium to further promote evaporation of the ink components.

The print evaluation results are recorded by visual inspection by five subjects.
In evaluation (1), A: no beading phenomenon, B: occurrence of beading In evaluation (2), A: no betarum phenomenon, B: no occurrence of betamula In evaluation (3), A: no color bleeding phenomenon, B: color Judgment was made as the occurrence of bleed, and the majority decision was adopted. The results are shown in Table 1 as tests 1-8.
Next, propylene glycol as a medium volatile moisturizing agent in the inks of the above compositions 1 to 4 is replaced with 10% by weight of glycerol, which is a low-volatile moisturizing agent having a boiling point of 290 ° C., and a cyan ink composition. 5, magenta ink composition 6, yellow ink composition 7, and black ink composition 8 were prepared.

The surface tensions of the inks having the above compositions 5 to 8 were all 27 mN / m.
In the above-described printing evaluation, the ink compositions 1 to 4 were replaced with the ink compositions 5 to 8, and the test 8 was performed in the same manner as the tests 1 to 8 under other conditions. The results are shown in Table 2.

[effect]
As apparent from Tests 1 to 7 in FIG. 4, 50% by weight or more of the ink adhering to the recording medium is evaporated in the first drying unit, and provided downstream of the first drying unit in the feeding direction of the recording medium. By further evaporating in the second drying 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 60% by weight or more of the ink adhering to the recording medium is evaporated in the first drying section, high-speed and high-quality ink jet recording is performed on a non-absorbing recording medium such as PET media. It was possible to do. 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 They were mixed together and color bleed was generated.

  Further, when 85% by weight or more of the ink adhering to the recording medium is evaporated in the first drying section, the recording target having high ink absorption performance such as PPC paper that is widely used as copy paper in general offices. High-quality inkjet recording could be performed on recording media with low ink absorption performance, such as glossy fine-coated paper used as media and printing paper, but non-absorbability of inks such as PET media In this recording medium, the amount of ink that contributes to printing is reduced, so that the width of the ruled line in the scanning direction of the head is narrowed. As a result, white stripes occur in a solid portion with a duty of 100%. Therefore, it is difficult to perform high-quality inkjet recording.

  Further, when 90% by weight or more of the ink adhering to the recording medium is evaporated in the first drying unit, the recording medium having a low ink absorption performance such as glossy fine coated paper used as a printing main paper. However, white streaks occur at a solid portion of 100% duty, making it difficult to perform high-quality inkjet recording.

As apparent from FIG. 5, since the ink composition contains glycerin, which is a low volatility humectant having a boiling point of 290 ° C., the first drying section particularly in a non-absorbable recording medium such as PET media. In this case, it takes a relatively long time to reach an appropriate amount even though an appropriate amount of ink is evaporated in this case. The beading and betting caused by the gathering phenomenon occurred, 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 recording medium with low or non-absorbing ink. In this case, as compared with a recording apparatus provided with a heating means for promoting ink drying at one place 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 drying. Since heat is efficiently applied to the recording material, the effect of suppressing the energy required for heating as a whole can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording apparatus, 10 ... Feed part, 11 ... Roll medium holder, 20 ... Conveyance part, 21 ... 1st feed roller, 30 ... Recording part, 31 ... Carriage, 32 ... Recording head, 33 ... Nozzle row, 34 DESCRIPTION OF SYMBOLS ... Platen, 40 ... 1st drying part, 41 ... Heat conduction heating means, 42 ... 1st nichrome wire, 43 ... 2nd feed roller, 50 ... 2nd drying part, 51 ... Convection heating means, 52 ... Drying furnace 53 ... Medium support surface, 54 ... Second nichrome wire, 55 ... Cross flow fan, 56 ... First axial fan, 57 ... Second axial fan, 58 ... Third axial fan, 59 ... First partition plate , 60 ... second partition plate, 61 ... first passage, 62 ... second passage, 63 ... inlet, 64 ... outlet, 65 ... third feed roller, 70 ... discharge section, 71 ... fourth feed roller, 72 ... 5th feed roller, 73 ... 6th feed roller, 4 ... 7 feed roller, 75 take-up roller, 90 ... drying apparatus, F ... recording medium, L ... ink, X ... width direction, Y ... feeding direction.

Claims (7)

A recording head that ejects ink to the surface of the recording medium is opposed to the recording head, and the recording medium is ejected from the recording head on a medium support portion that supports the recording medium from the back surface. A first drying step for evaporating 50 to 85% by weight of the ink adhering to the recording medium;
A recording method comprising: a second drying step of drying the recording medium that has undergone the first drying step on the downstream side of the recording medium in the feeding direction of the recording medium. The recording method according to claim 1,
The recording method according to claim 1, wherein the first drying step evaporates 60 to 80% by weight of the ink attached to the recording medium with respect to the recording medium on which the ink is ejected from the recording head. The recording method according to claim 1 or 2,
The recording method according to claim 1, wherein the first drying step is a heat conduction type and / or a convection type. The recording method according to any one of claims 1 to 3,
The recording method, wherein the second drying step is a convection type. The recording method according to any one of claims 1 to 4,
The recording method, wherein the recording medium is a film material. The recording method according to any one of claims 1 to 5,
The ink contains at least (1) a colorant, (2) a resin, (3) a water-soluble resin solvent, (4) a moderately volatile humectant, (5) a water-soluble penetrating solvent, (6) a surfactant, and (7) water. A recording method, wherein the water-soluble resin solvent, the medium volatile humectant, and the water-soluble penetrant are all organic solvents having a boiling point of 100 ° C. or higher and 250 ° C. or lower. The recording method according to any one of claims 1 to 6,
The ink contains at least (1) a pigment as a colorant 0.5 to 10% by weight
(2) Single or two or more kinds of resins selected from the group consisting of a colorant dispersant, a resin emulsion or a water-soluble resin 0.5 to 10% by weight
(3) N-methylpyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, 2-pyrrolidone, dimethylsulfoxide, ε-caprolactam, methyl lactate, ethyl lactate, isopropyl lactate, butyl lactate, ethylene glycol monomethyl as a water-soluble resin solvent Ether, ethylene glycol dimethyl 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, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol Dimethyl ether, 2-10% by weight alone or two or more kinds of organic solvent selected from the group consisting of 1,4-dioxane
(4) From the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, hexylene glycol, and 2,3-butanediol as medium volatile humectants Single or two or more organic solvents selected 2 to 15% by weight
(5) n-butanol, 1,2-hexanediol, 1,3-hexanediol, 1,2-heptanediol, 1,3-heptanediol, 1,2-octanediol, 1, Single or two or more kinds of organic compounds selected from the group consisting of 3-octanediol, 1,2-pentanediol, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, propylene glycol monobutyl ether 1-8% by weight of solvent
(6) A single or two or more kinds of surfactants selected from the group consisting of acetylene glycol surfactants or silicone surfactants 0.5 to 2% by weight
(7) A recording method comprising 50 to 80% by weight of water.

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