JP7172654B2 - Drying device, device for discharging liquid - Google Patents

Description

The present invention relates to a drying device and a device for ejecting liquid .

2. Description of the Related Art As a printing apparatus that applies liquid to an object to be heated such as roll paper, continuous form paper, web, sheet, etc., there is one that is provided with a drying device to facilitate drying of the applied liquid.

For example, along the moving direction of the object to be heated, a long heater that is long in a direction perpendicular to the direction of movement of the object to be heated and a blower having a long nozzle extending in a direction perpendicular to the direction of movement of the object to be heated are alternately arranged. There is a device in which air heated by a heater is blown onto an object to be heated from a nozzle of an air blower (Patent Document 1).

Further, as a hot air drying device in an inkjet recording apparatus, there is one that includes an intake section that supplies air to an air blowing source and a hot air circulation section that supplies hot air collected by an exhaust section to the intake section (Patent Document 2).

JP 2016-168805 A Japanese Patent No. 5893428

By the way, when the gas containing the organic solvent vaporized by drying in the drying device is reintroduced into the drying device and circulated, the concentration of the organic solvent vapor inside the drying device increases, the drying property of the liquid decreases, and the explosion-proof safety is improved. There is a problem that the

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to suppress a decrease in dryness while circulating gas, and to improve explosion-proof safety.

In order to solve the above problems, the drying apparatus according to the present invention includes:
drying means for warming the liquid composition on the object to be dried;
a gas circulation means for circulating the gas containing the volatile components of the organic solvent heated and volatilized by the drying means and reusing it for drying;
and concentration adjusting means for adjusting the concentration of the recycled volatile component,
The drying means includes radiant heating means for applying radiant heat to the object to be dried, and air blowing means for blowing the air heated by the radiant heating means to the object to be dried.
It was configured.

ADVANTAGE OF THE INVENTION According to this invention, the fall of dryness can be suppressed, and explosion-proof safety can also be improved, circulating gas.

1 is a schematic explanatory diagram of an example of a printing device as a device for ejecting liquid according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic explanatory drawing of the drying apparatus which concerns on 1st Embodiment of this invention. It is plane explanatory drawing of the same drying apparatus. It is a perspective explanatory view of the ventilation means of the same drying apparatus. It is a schematic explanatory drawing of the drying apparatus which concerns on 2nd Embodiment of this invention. It is a schematic explanatory drawing of the drying apparatus which concerns on 3rd Embodiment of this invention. It is a schematic explanatory drawing of the drying apparatus which concerns on 4th Embodiment of this invention. It is a schematic explanatory drawing of the drying apparatus which concerns on 5th Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory diagram of an example of a printing device as a device for ejecting liquid according to the embodiment.

The printing apparatus 100 is an inkjet recording apparatus, and applies liquid by ejecting ink of a desired color onto continuous paper 110, which is a member to be conveyed (member to be conveyed, object to be heated, object to be dried). It has a liquid applying section 101 including a liquid ejection head 111 (111A to 111D) as means.

For example, the liquid applying unit 101 is provided with full-line liquid ejection heads 111 for four colors from the upstream side in the conveying direction of the continuous paper 110 . , yellow Y liquid. Note that the types and number of colors are not limited to this.

The continuous paper 110 is fed out from the unwinding roller 102, sent out by the transport roller 112 of the transport unit 103 onto the transport guide member 113 arranged facing the liquid application unit 101, and guided by the transport guide member 113. , is transported (moved) facing the liquid applying unit 101 .

The continuous paper 110 to which liquid has been applied by the liquid applying section 101 passes through a drying apparatus (drying section) 104 according to the present invention, is sent by a discharge roller 114 , and is taken up by a take-up roller 105 .

Organic solvents, water, coloring materials, resins, additives, etc. of liquids (inks) used in the printing apparatus 1 will be described.

<Organic solvent>
The organic solvent to be used is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

Specific examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, nitrogen-containing heterocyclic compounds such as γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N- Amides such as dimethylpropionamide and 3-butoxy-N,N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine, and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane, and thiodiethanol, propylene carbonate, and ethylene carbonate. etc.

It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also provides good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a printing medium.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose. 20% by mass or more and 60% by mass or less is more preferable.

<Water>
The content of water in the ink is not particularly limited and can be appropriately selected according to the purpose. % to 60% by mass is more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.

An inorganic pigment or an organic pigment can be used as the pigment. These may be used individually by 1 type, and may use 2 or more types together. Mixed crystals may also be used.

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

As inorganic pigments, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as contact method, furnace method, thermal method, etc. can be used.

Organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinoflurone pigments, etc.). , dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments for black include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (C.I. Pigment Black 11). , metals such as titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1).

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

As dyes, acid dyes, direct dyes, reactive dyes, and basic dyes can be used without particular limitation, and may be used singly or in combination of two or more.

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

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability. It is below.

In order to disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing it, a method of dispersing using a dispersant, etc.

As a method of making a self-dispersing pigment by introducing a hydrophilic functional group into a pigment, for example, a self-dispersing pigment that is dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon). can be used.

As a method for dispersing the pigment by coating the surface of the pigment with a resin, a method in which the pigment is encapsulated in microcapsules and dispersible in water can be used. This can be rephrased as a resin-coated pigment. In this case, all the pigments mixed in the ink need not be coated with a resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. may be

Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant typified by surfactants.

As the dispersant, it is possible to use, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. depending on the pigment.

RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as a dispersant.

A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
Inks can be obtained by mixing materials such as water and organic solvents with coloring materials. Ink can also be produced by mixing a pigment, water, a dispersant, and the like to form a pigment dispersion, and then mixing materials such as water and an organic solvent.

The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. Dispersion should be carried out using a disperser.

The particle diameter of the pigment in the pigment dispersion is not particularly limited, but the dispersion stability of the pigment is improved, and the image quality such as ejection stability and image density is improved. 500 nm or less is preferable, and 20 nm or more and 150 nm or less is more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. % or more and 50 mass % or less is preferable, and 0.1 mass % or more and 30 mass % or less is more preferable.

The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator, or the like, if necessary.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additive>
Surfactants, antifoaming agents, antiseptic antifungal agents, anticorrosive agents, pH adjusters, etc. may be added to the ink as necessary.

<Surfactant>
Any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used as surfactants.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among them, those that do not decompose even at high pH are preferable. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as water-based surfactants. As the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.

Examples of fluorine-based surfactants include perfluoroalkylsulfonic acid compounds, perfluoroalkylcarboxylic acid compounds, perfluoroalkylphosphoric acid ester compounds, perfluoroalkylethylene oxide adducts, and perfluoroalkyl ether groups in side chains. Polyoxyalkylene ether polymer compounds are particularly preferred due to their low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonate. Examples of the perfluoroalkylcarboxylic acid compounds include perfluoroalkylcarboxylic acids and perfluoroalkylcarboxylic acid salts. As the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain, a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and a perfluoroalkyl ether group in a side chain Examples thereof include salts of polyoxyalkylene ether polymers. Counter ions of salts in these _{fluorosurfactants} include Li, Na, K, _NH4 , _NH3CH2CH2OH , _{NH2 ( CH2CH2OH} ) ₂ , and _{NH ( CH2CH2OH} ). ₃ and the like.
Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine and the like.

Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.

Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates.

These may be used individually by 1 type, or may use 2 or more types together.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples include polydimethylsiloxane modified at both chain ends, and polyether-modified silicone-based surfactants having polyoxyethylene groups or polyoxyethylene-polyoxypropylene groups as modifying groups exhibit excellent properties as water-based surfactants. preferable.

As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. Commercially available products are available from, for example, BYK Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nihon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.

The above polyether-modified silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include those introduced into the side chain of the Si portion of siloxane.

（但し、一般式（Ｓ-1）式中、ｍ、ｎ、ａ、及びｂは整数を表わす。 Ｒ及びＲ’はアルキル基、アルキレン基を表わす。）

(However, m, n, a, and b in general formula (S-1) represent integers. R and R' represent an alkyl group and an alkylene group.)

Commercially available products can be used as the above polyether-modified silicone-based surfactants. 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Corporation), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like.

As the fluorosurfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.

Examples of fluorine-based surfactants include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain is preferable because of its low foamability, and in particular, fluorine-based compounds represented by general formulas (F-1) and (F-2) Surfactants are preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.

In the compound represented by the general formula (F-2), Y is H, or CnF _2n+1 and n is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ -CnF _2n+1 and n is 4 to 6. Integer, or CpH _2p+1 where p is an integer from 1-19. a is an integer from 4 to 14;

Commercially available products may be used as the fluorosurfactant.

Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fleurard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (both manufactured by Sumitomo 3M); Megafac F-470, F -1405, F-474 (both manufactured by Dainippon Ink and Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (both , manufactured by DuPont); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova Co., Ltd.), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc., and among these, good print quality, especially color development, permeability to paper , Du Pont FS-300, Neos Co., Ltd. FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW, Polyfox PF-151N manufactured by Omnova and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be appropriately selected according to the purpose. % or more and 5 mass % or less is preferable, and 0.05 mass % or more and 5 mass % or less is more preferable.

<Antifoaming agent>
The antifoaming agent is not particularly limited, and examples thereof include silicone antifoaming agents, polyether antifoaming agents, and fatty acid ester antifoaming agents. These may be used individually by 1 type, or may use 2 or more types together. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

<Preservative and antifungal agent>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Antirust agent>
The rust inhibitor is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and can be appropriately selected depending on the intended purpose. For example, viscosity, surface tension, pH and the like are preferably within the following ranges.

The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, more preferably 5 mPa·s or more and 25 mPa·s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. more preferred. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume of 1.2 mL, rotation speed of 50 rpm, and measurement can be performed for 3 minutes.

The surface tension of the ink is preferably 35 mN/m or less, and more preferably 32 mN/m or less at 25° C., from the viewpoint that the ink is suitably leveled on the print medium and the drying time of the ink is shortened.

The pH of the ink is preferably from 7 to 12, more preferably from 8 to 11, from the viewpoint of preventing corrosion of metal members in contact with the liquid.

Next, the drying apparatus according to the first embodiment will be described with reference to FIGS. 2 to 4. FIG. 2 is a schematic explanatory view of the drying apparatus, FIG. 3 is a plan view of the drying apparatus, and FIG. 4 is a perspective view of air blowing means of the drying apparatus.

The drying device 104 has a plurality of air knives (six in total) blowing means along the direction of movement of the continuous paper 110 to be dried (direction of arrow Y: hereinafter referred to as “conveyance direction Y”). 120 are arranged.

Radiation heating means 121 for heating the air inside the air knives 120 is arranged between the adjacent air knives 120 , 120 outside each air knife 120 .

The air knife 120 has an elongated chamber (housing) 131 and is provided with a nozzle 132 which is a slit-shaped blowout opening communicating with an internal space 133 of the chamber 131 . The slit-shaped outlet 132 may be a single slit or a plurality of slits arranged in the width direction. The nozzle 132 has a length corresponding to the width in the direction intersecting the transport direction Y. As shown in FIG.

Further, the air knife 120 of this embodiment has a fan 134 as an airflow generating means for sending gas into the internal space 133 of the chamber 131 at one longitudinal end of the chamber 131 . As the fan 134 as the airflow generating means, for example, a counter-rotating fan or the like can be used to obtain a large air volume.

Here, the air knife 120 is a first air blowing means in which a fan 134 is arranged as an airflow generating means on one end side of the direction intersecting the moving direction (conveying direction Y) of the continuous paper 110 .

The fan 134 of the air knife 120A generates an airflow in the direction of the arrow b inside the chamber 131, and the airflow is jetted (blown out) from the nozzle 132 in the direction of the arrow d in FIG.

The radiant heating means 121 are arranged between the air knives 120, 120 adjacent in the conveying direction Y. As shown in FIG. That is, the air knives 120 and the radiant heating means 121 are alternately arranged.

Thereby, the air inside two adjacent air knives 120, 120 can be heated by one radiant heating means 121. FIG. However, the radiant heating means 121 can also be arranged, for example, every two airs 120 .

As the radiation heating means 121, an infrared heater that emits infrared rays having a maximum wavelength in the absorption wavelength band of moisture contained in the liquid is preferable. Further, it is preferable to use a carbon heater using carbon as the material of the heating element.

The air knife 120 and the radiant heating means 121 constitute a drying means 141 for drying the liquid composition (ink) on the continuous paper 110 to be dried. A plurality of drying means 141 are surrounded by an apparatus casing (housing) 140 .

A temperature detecting means 150 for detecting the surface temperature of the continuous paper 110 is provided downstream of the drying device 104 . As the temperature detection means 150, non-contact temperature detection means is preferable, and for example, an infrared surface thermometer is preferable.

A gas circulating means 200 is arranged outside the device exterior 140 to circulate the gas containing the volatile component of the organic solvent heated by the drying means 141 and reuse it for drying.

The gas circulation means 200 includes a circulation path 202 including an exhaust port 201 serving as a circulation path entrance for exhausting the gas including steam inside the drying apparatus provided in the apparatus housing 140, and the circulation path 202 as a plurality of drying means 141. It has a distribution path 300 that distributes the air to the air knife 120 and circulates it, and a circulation blower means 220 .

In addition, an outside air introduction path 203 for introducing outside air into the circulation path 202 of the gas circulation means 200 is provided, and the outside air is mixed with the gas in the circulation path 202 inside the gas circulation means 200 to adjust the concentration of the volatile component of the organic solvent. A circulation rate adjusting means 210 is provided as a concentration adjusting means for adjusting the concentration.

Next, an outline of the operation of this drying device 104 will be described.

The continuous paper 110 to which the liquid is applied by the liquid applying unit 101 is conveyed in the conveying direction Y and passes through the drying device 104 .

In the drying device 104, by energizing the radiant heating means 121, the radiant heat radiated from the radiant heating means 121 is directly applied to the conveyed continuous paper 110, and the continuous paper 110 is heated by the radiant heat. be done.

Also, the air in the internal space 133 of the chamber 131 of the air knife 120 is heated by the radiant heat of the radiant heating means 121 . Then, by driving the fan 134 to suck air, heated air (warm air) is blown out from the nozzle 132 in the direction of the arrow d and is blown onto the continuous paper 110 being conveyed.

After the continuous paper 110 is transported downstream, the surface temperature of the continuous paper 110 is detected by the temperature detecting means 150 . At this time, the power supplied to the radiant heating means 121 is controlled so that the surface temperature of the continuous paper 110 becomes a predetermined value.

By the above operation, the liquid on the continuous paper 110 is heated, the vapor pressure of the liquid (ink) is increased, and the continuous paper 110 and the liquid are dried.

The gas containing the volatile component of the organic solvent generated by heating and evaporating the liquid on the continuous paper 110 is blown into the circulation path 202 from the exhaust port 201 arranged in the drying device 104 by the circulation air blower 220 . exhausted.

The air containing steam exhausted to the circulation path 202 passes through the circulation path 202 and is recirculated to the upstream side of the fan 134 of the air knife 120, and is sucked by the fan 134 to enter the internal space 133 of the air knife 120. introduced into

Since the gas introduced into the air knife 120 has a higher temperature than the outside air, the temperature of the air rises to the temperature necessary for drying the ink, so the power consumption of the radiant heating means 121 is reduced.

Further, the vapor concentration of the gas containing the organic solvent having a high vapor concentration flowing through the circulation path 202 is reduced by being mixed with the outside air through the circulation rate adjusting means 210 having the outside air introduction path 203 .

In this way, the vapor concentration-reduced gas is circulated inside the drying device 104 , thereby suppressing an increase in the organic solvent vapor concentration inside the device housing 140 of the drying device 104 . As a result, it is possible to improve the safety against explosion while suppressing the deterioration of the drying property of the liquid.

Here, the "circulation rate" adjusted by the circulation rate adjusting means 210 is Vex/(Vex+Ve) where Vex is the flow rate exhausted from the exhaust port 201 of the drying device 104 and Ve is the flow rate Ve of the air introduced from the outside air. is indicated by

Next, a second embodiment of the invention will be described with reference to FIG. FIG. 5 is a schematic explanatory diagram of the drying apparatus according to the same embodiment, and an explanatory diagram showing along the transport direction Y the amount of organic solvent vapor generated by heating the liquid.

In this embodiment, a plurality of exhaust ports 201 are arranged along the transport direction Y of the continuous paper 110 . Here, the exhaust port 201 is arranged above the air knife 120 .

As described above, the organic solvent contained in the ink has a vapor pressure lower than that of water in terms of drying performance and ejection reliability in the nozzles of the liquid ejection head 111. Therefore, on the upstream side of the transport, Although the water evaporates, there is a dry section A in which the organic solvent hardly evaporates, and the evaporation of the organic solvent starts from the position P where the evaporation of the water has almost finished.

Therefore, the vapor concentration of the organic solvent generated in the drying section A is low, and the vapor concentration of the organic solvent generated in the drying section B after the position P is high.

Therefore, in the present embodiment, a plurality of exhaust ports 201 (201a to 201f) are provided in the direction along the conveying direction Y of the continuous paper 110, and flow control means 211 ( 211a-211f).

Then, the opening amount of the flow rate adjusting means 211a to 211c on the upstream side in the transport direction corresponding to the position of the drying section A where the vapor concentration of the organic solvent is low is reduced, and the transport corresponding to the position of the drying section B where the vapor concentration of the organic solvent is high. The opening amount of the flow control means 211d to 211f on the downstream side in the direction is increased.

As a result, among a plurality of circulation path entrances (exhaust ports 201a to 201f) arranged along the transport direction of the drying target, the circulation path entrances (exhaust ports 201d to 201f) located downstream in the transport direction are used for the flow. The flow rate of the gas flowing through is greater than the flow rate of the gas flowing in from the circulation path inlets (exhaust ports 201a to 201c) located on the upstream side.

By configuring in this way, it is possible to increase the inflow amount (exhaust amount) of the gas from the drying section B where the vapor concentration of the organic solvent is high, and efficiently reduce the vapor concentration inside the drying device 104. can be done. Therefore, explosion-proof safety can be further improved.

Here, the opening amount (inflow amount) of the flow rate adjusting means 211 is at least the type, size, number of prints, printing time, printing speed, type of liquid composition, and discharge amount of the liquid composition to be dried. You can decide accordingly.

Next, a third embodiment of the invention will be described with reference to FIG. FIG. 6 is a schematic explanatory diagram of a drying apparatus according to the same embodiment.

In this embodiment, gas detection means 240 is provided as concentration detection means for detecting the organic solvent concentration in the circulation path 202 in the second embodiment.

Then, when the vapor concentration (detection result) of the gas flowing inside the circulation path 202 detected by the gas detection means 240 is equal to or lower than a predetermined concentration, the adjustment control means 250 controls the circulation amount adjustment means 210 to control the amount of outside air introduced. and increase the circulation rate. As a result, the exhausted gas is recirculated while the temperature is high, and power consumption can be reduced.

On the other hand, when the vapor concentration of the gas flowing inside the circulation path 202 detected by the gas detection means 240 exceeds a predetermined concentration, the circulation amount adjustment means 210 is controlled to increase the amount of outside air introduced and decrease the circulation rate. As a result, explosion-proof safety can be ensured.

In each of the above-described embodiments, an example in which the air knife as the blower is arranged in the direction perpendicular to the conveying direction Y is described, but the air knife as the blower is arranged at an angle other than perpendicular to the conveying direction Y. may be arranged in a direction intersecting with each other.

Further, in each of the above-described embodiments, the gas to be introduced for mixing may be the gas outside the gas circulation means 200, for example, the gas having a low concentration of the solvent inside the drying device 104 may be used. When adjusting the concentration by exhausting the solvent at the same time as mixing the solvent, it is preferable to use the gas from outside the drying device 104 or the gas from the outside of the printing device 100 for mixing.

Next, a fourth embodiment of the invention will be described with reference to FIG. FIG. 7 is a schematic explanatory diagram of a drying apparatus according to the same embodiment.

In this embodiment, a filter 260 capable of blocking or absorbing the organic solvent is provided in the circulation path 202 as concentration adjusting means. By blocking or absorbing the organic solvent with this filter 260, the concentration of the organic solvent is adjusted to be reduced.

By providing the filter 260 capable of blocking or absorbing the organic solvent in this manner, it can be used also as a filter for suppressing the amount of solvent released to the outside air, thereby simplifying the device configuration.

Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a schematic explanatory diagram of a drying apparatus according to the same embodiment.

In this embodiment, a filter 260 capable of blocking or absorbing the organic solvent is provided between the circulation rate adjusting means 210 and the circulation blowing means 220 in the third embodiment.

By using the gas outside the gas circulation means 200 together with the filter 260 in this way, the frequency of replacement of the filter 260 can be reduced. In addition, a certain amount of the organic solvent can be exhausted in order to prevent the high-concentration organic solvent from staying for a long time.

Further, in each of the above embodiments, an example in which the member to be conveyed is a continuous form has been described, but the present invention is not limited to this. In addition to recording media such as elongated sheet materials, printed materials such as electronic circuit board sheets such as wallpaper and prepreg may also be used.

In addition to recording images such as letters and figures with a liquid such as ink on the object to be dried, it is also possible to apply meaningless images such as patterns with a liquid such as ink for the purpose of decoration and decoration. you can

In the present application, the liquid to be applied is not particularly limited, but preferably has a viscosity of 30 mPa·s or less at normal temperature, under normal pressure, or by heating or cooling. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, solutions, suspensions, emulsions, etc. These are, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used for applications such as liquids for liquids and material liquids for three-dimensional modeling.

When the liquid ejection head is used as the liquid applying means, the energy generating source for ejecting the liquid may be a piezoelectric actuator (laminated piezoelectric element or thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor, or a vibration. It includes those using an electrostatic actuator consisting of a plate and a counter electrode.

Note that printing in the present application has the same meaning as image formation, recording, printing, printing, and the like.

101 liquid application unit 104 drying device (drying unit)
110 Continuous paper (for drying)
120 air knife (blowing means)
121 radiation heating means (heating means)
131 chamber 132 nozzle (outlet)
133 Internal space 134 Fan (airflow generating means)
150 drying means 200 gas circulation means 201 exhaust port (circulation path inlet)
202 circulation path 203 outside air introduction path 210 circulation rate adjusting means 211 flow rate adjusting means

Claims (10)

drying means for warming the liquid composition on the object to be dried;
a gas circulation means for circulating the gas containing the volatile components of the organic solvent heated and volatilized by the drying means and reusing it for drying;
and concentration adjusting means for adjusting the concentration of the recycled volatile component,
The drying means includes radiant heating means for applying radiant heat to the object to be dried, and air blowing means for blowing the air heated by the radiant heating means to the object to be dried.
A drying device characterized by: 2. The drying apparatus according to claim 1, wherein the concentration adjusting means adjusts the concentration of the volatile components of the organic solvent by mixing the gas inside the gas circulation means with the gas outside the gas circulation means. Device. 3. The drying apparatus according to claim 1, wherein the concentration adjusting means has a filter capable of blocking or absorbing the organic solvent, and the filter adjusts the concentration of the organic solvent to be reduced. A plurality of circulation path inlets arranged along the direction of conveyance of the drying object,
3. The method according to claim 2, wherein a flow rate of the gas flowing in from the circulation path inlet positioned downstream in the conveying direction is greater than a flow rate of the gas flowing in from the circulation path inlet positioned upstream in the conveying direction. Drying equipment as described. 5. The rate of circulation of the gas by the gas circulation means is determined according to at least one of the type, size, number of objects to be dried, and time for applying the liquid composition. The drying device described in . Having concentration detection means for detecting the concentration of the organic solvent,
6. The drying apparatus according to claim 2, wherein said concentration adjusting means determines a circulation rate according to a detection result of said organic solvent concentration. The gas circulating means exhausts the gas in the device housing containing the radiant heating means and the air blowing means to a circulation path outside the device housing.
The drying apparatus according to claim 1, characterized in that: A plurality of the radiant heating means and the blowing means are arranged along the conveying direction of the object to be dried,
The radiant heating means heats the object to be dried and the air in the blowing means.
The drying apparatus according to claim 1, characterized in that: A plurality of the air blowing means are arranged along the transport direction of the object to be dried,
The circulation path includes a circulation path inlet through which the gas circulation means exhausts the gas in the device housing, and a distribution path that distributes and circulates the gas from the front side of the device to the plurality of air blowing means.
The drying apparatus according to claim 1, characterized in that: liquid applying means for applying liquid to the member being conveyed;
A device for ejecting liquid, comprising: a drying device according to any one of claims 1 to 9 .

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