Inkjet recording method and inkjet recording device

Abstract

The present invention relates to an inkjet recording method with good ejection stability and an inkjet recording device having an ejection head, wherein the ejection head includes a nozzle plate having a nozzle for ejecting ink containing a resin, an organic solvent and water, a liquid chamber connected to the nozzle, and a pressure generating mechanism for generating pressure in the liquid chamber, wherein a first drive pulse and a second drive pulse are applied by the pressure generating mechanism to eject the ink, wherein the viscosity of the ink at 25° C. is greater than 9.0 mPa·s and less than 11.0 mPa·s, and the viscosity of the ink at 36° C. is greater than 6.5 mPa·s and less than 11.0 mPa·s, and satisfies (1) the first drive pulse includes a first waveform element for applying a voltage exceeding a reference voltage after applying a voltage less than a reference voltage, and a second waveform element for applying a voltage less than the reference voltage after the first waveform element; and (2) the second drive pulse includes a third waveform element for pulling and pushing out a curved liquid surface of the nozzle surface without ejecting ink.

Description

Technical Field

[0001] The present invention relates to an inkjet recording method and an inkjet recording apparatus. Background Art

[0002] In recent years, permeable recording media such as textiles and canvas fabrics have been used in industrial applications such as wallpapers, advertisements, and billboards, and various inks for such permeable recording media have been developed.

[0003] As such ink, for example, solvent-based ink using an organic solvent as a solvent, ultraviolet curing ink containing a polymerizable monomer as a main component, and the like are widely used.

[0004] However, the above-mentioned solvent-based ink has a problem that the evaporation of the organic solvent may affect the environment. In addition, the above-mentioned ultraviolet curing ink has a problem that the selection of polymerizable monomers used is limited from the perspective of safety.

[0005] Therefore, inks containing aqueous inks that have a small environmental load and can directly record on a permeable recording medium have been proposed (for example, see Patent Document 1).

[0006] In the inkjet recording device using the above-mentioned water-based ink, when high-resolution images are produced, it is necessary to increase the frequency of ejecting ink droplets from the nozzle. However, if the ejection frequency is increased, the ink is heated due to vibration, which causes the viscosity of the ink to decrease. When the viscosity of the ink decreases, the meniscus formed inside the nozzle becomes unstable, and there is a problem that the ink droplets are not ejected or the speed of the droplets varies.

[0007] By using high-viscosity ink, the viscosity drop caused by temperature rise can be reduced. However, when the ink is ejected, satellite droplets are generated at the end of the main droplet. Since they land at a different position from the main droplet, there is a problem of reduced image quality.

[0008] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2006-142588 Summary of the invention

[0010] An object of the present invention is to provide an inkjet recording method having excellent ejection stability.

[0011] As a method for solving the above-mentioned problem, the inkjet recording method of the present invention relates to an inkjet recording method, which uses an inkjet recording device having an ejection head, wherein the ejection head includes a nozzle plate having a nozzle for ejecting ink containing a resin, an organic solvent, and water, a liquid chamber connected to the nozzle, and a pressure generating mechanism for generating pressure in the liquid chamber.

[0012] The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink,

[0013] The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C.,

[0014] The inkjet recording method satisfies the following conditions (1) and (2),

[0015] (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element;

[0016] (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus of the nozzle surface without ejecting the ink.

[0017] According to the present invention, an inkjet recording method having excellent ejection stability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. 1 is a diagram showing an example of an image forming apparatus for implementing the image forming method of the present invention.

[0019] Figure 2 Shown is Figure 1 An explanatory diagram of an example of a main box of an image forming apparatus.

[0020] Figure 3 FIG. 1 is a diagram showing an example of a driving waveform for implementing the image forming method of the present invention.

[0021] Figure 4 FIG. 1 is a diagram showing an example of a driving waveform for implementing the image forming method of the present invention.

[0022] The symbols in the figure are explained as follows:

[0023] 400: Image forming device

[0024] 401: Shell

[0025] 401c: Coverage

[0026] 404: Cartridge holding component

[0027] 410, 410k, 410c, 410m, 410y: Main box

[0028] 411: ink storage unit

[0029] 413: ink outlet

[0030] 414: Storage container box

[0031] 420: Organization Department

[0032] 434: Injection head

[0033] 436:Supply hose

[0034] L: Ink storage container DETAILED DESCRIPTION

[0035] (Inkjet Recording Method)

[0036] The inkjet recording method of the present invention uses an inkjet recording device having an ejection head, wherein the ejection head includes a nozzle plate having nozzles for ejecting ink containing resin, organic solvent and water, a liquid chamber connected to the nozzle, and a pressure generating mechanism for generating pressure in the liquid chamber.

[0037] The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink,

[0038] The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C.,

[0039] The inkjet recording method satisfies the following conditions (1) and (2),

[0040] (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element;

[0041] (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus of the nozzle surface without ejecting the ink.

[0042] <Injection head>

[0043] The above-mentioned nozzle preferably has a nozzle, a nozzle plate having the above-mentioned nozzle, a liquid chamber connected to the above-mentioned nozzle, and a pressurization chamber that generates pressure in the above-mentioned liquid chamber through a pressure generating mechanism, and has a stimulation generating mechanism and a heating mechanism.

[0044] The ink is ejected by the ejection head to form a printed layer.

[0045] -Nozzle Plate-

[0046] The nozzle plate includes a nozzle substrate and an ink repellent film on the nozzle substrate.

[0047] - Pressurized chamber -

[0048] The pressurizing chamber generates pressure in the liquid chamber by a pressure generating mechanism.

[0049] The pressurization chambers are a plurality of separate flow paths respectively arranged corresponding to the plurality of nozzle holes provided on the nozzle plate and connected to the nozzle holes, and are sometimes also referred to as ink flow paths, pressurization chambers, pressure chambers, ejection chambers, liquid chambers, etc.

[0050] The pressure generating mechanism is a mechanism that generates pressure by applying a voltage using a basic drive waveform including a first drive pulse and a second drive pulse.

[0051] The pressure generating mechanism is not particularly limited as long as it can apply the voltage of the driving waveform, and can be appropriately selected according to the purpose, and examples thereof include piezoelectric elements and heat. Among them, piezoelectric elements are preferred.

[0052] Reference Figure 3 The basic driving waveform is described.

[0053] Figure 3 The basic driving waveform is a driving waveform used to eject droplets using an ejection head.

[0054] The basic driving waveform includes a waveform element S1 that maintains a reference voltage Vref, a waveform element S2 that drops from the reference voltage Vref to a voltage Vx after the waveform element S1, a waveform element S3 that maintains the voltage Vx after the waveform element S2, a waveform element S4 that rises to a voltage Vy after the waveform element S3, a waveform element S5 that maintains the voltage Vy after the waveform element S4, a waveform element S6 that drops from the voltage Vy to the reference voltage Vref after the waveform element S5, a waveform element S7 that maintains the voltage Vref after the waveform element S6, a waveform element S8 that drops from the reference voltage Vref to a voltage Vz after the waveform element S7, a waveform element S9 that maintains the voltage Vz after the waveform element S8, and a waveform element S10 that rises to the reference voltage Vref after the waveform element S9.

[0055] When using the above-mentioned ejection head to eject droplets, main droplets and satellite droplets are generally ejected. The main droplets are main droplets, and the tiny droplets located at the tail of the main droplets are satellite droplets.

[0056] The basic driving waveform includes a first driving pulse P1 having a first waveform element and a second waveform element, and a second driving pulse P2 having a third waveform element.

[0057] The first waveform element is composed of waveform elements S1 to S4.

[0058] The first waveform element applies a voltage lower than a reference voltage and then applies a voltage higher than the reference voltage, thereby ejecting the droplets through waveform elements S3 and S4. In addition, in the waveform element S4, a voltage (high voltage) that is positive compared to the reference voltage Vref is applied to reduce the landing position deviation of the main droplet and the satellite droplet, thereby improving the image quality.

[0059] In the waveform element S4, when Vy=Vref, the driving waveform does not include the second waveform element. Compared with the driving waveform not including the second waveform element, the driving waveform including the second waveform element reduces the landing position deviation of the main droplet and the satellite droplet, thereby improving the image quality. Since the landing position deviation of the main droplet and the satellite droplet can be avoided, the landing position deviation is avoided by using the driving waveform including the second waveform element.

[0060] The second waveform element is composed of waveform elements S5 to S7.

[0061] The second waveform element applies a voltage less than or equal to the reference voltage Vref after the first waveform element by applying a voltage less than or equal to the reference voltage after the first waveform element.

[0062] The second waveform element preferably provides 1 / 2 or more of the natural vibration period of the liquid chamber from the start of droplet ejection by the first drive pulse, more preferably 1 / 2 or more and 1 or less. This reduces positional deviation between the main droplet and the satellite droplet, and improves image quality.

[0063] In the first waveform element and the second waveform element, the time Ta (μsec) required from the start of the waveform element S4 to the start of the waveform element S6 preferably satisfies Ta≤1 / 2Tc (Tc: natural vibration period of the liquid chamber). As a result, the speed of the satellite droplet is accelerated, thereby avoiding the deviation of the landing position of the main droplet and the satellite droplet.

[0064] The natural vibration period refers to the time when the droplet velocity increases the most with respect to the time interval (Tb) between the driving pulse P1 and the driving pulse P2.

[0065] The natural vibration period is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 6 μsec or more and 9 μsec or less.

[0066] The third waveform element is composed of waveform elements S8 to S10.

[0067] The third waveform element applies a voltage that is negative (lower voltage) than the reference voltage Vref and a voltage that is greater than the reference voltage Vref to the liquid chamber, thereby pulling in and pushing out the meniscus of the nozzle surface without ejecting a droplet.

[0068] In the above-mentioned waveform elements S8 to S10, when Vz=Vref, it will become a driving waveform that does not include the above-mentioned third waveform element. However, compared with the driving waveform that does not include the above-mentioned third waveform element, the driving waveform including the above-mentioned third waveform element can also stabilize the vibration of the curved liquid surface when continuously ejecting droplets, avoid the occurrence of abnormal ejection such as non-ejection or bending of ink droplets, and can print images well.

[0069] <Stimulus generating mechanism>

[0070] The stimulus generating mechanism is a mechanism for generating a stimulus to be applied to the ink.

[0071] There are no particular restrictions on the stimulus in the above-mentioned stimulus generating mechanism, and it can be appropriately selected according to the purpose, for example, heat (temperature), pressure, vibration, light, etc. can be cited. These can be used alone or in combination of two or more. Among them, heat and pressure can be preferably cited. As the above-mentioned stimulus generating mechanism, for example, a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a lamp, etc. can be cited. As the above-mentioned stimulus generating mechanism, specifically, piezoelectric actuators such as piezoelectric elements, electrothermal conversion elements using heating resistors, etc. and utilizing the phase change caused by film boiling of ink can be cited, shape memory alloy actuators that use temperature changes to cause metal phase changes, electrostatic actuators that use electrostatic forces, etc. can be cited.

[0072] When the stimulus is "heat", thermal energy corresponding to the recording signal is applied to the ink in the inkjet head, for example, using a thermal head, etc. Methods that can be cited include using the thermal energy to generate bubbles in the ink, and ejecting the ink as droplets from the nozzle holes of the nozzle plate by the pressure of the bubbles.

[0073] In the case where the stimulus is "pressure", for example, a voltage is applied to a piezoelectric element so that the piezoelectric element is bent, and the piezoelectric element is bonded to a position called a pressure chamber in the ink flow path in the inkjet head. As a result, the volume of the pressure chamber shrinks, and the ink is ejected as droplets from the nozzle hole of the inkjet head.

[0074] Among them, a piezoelectric method in which a voltage is applied to a piezoelectric element to cause ink to fly is preferred.

[0075] <Heating mechanism>

[0076] The heating mechanism is a mechanism for heating the printing object. The heating mechanism includes a mechanism for heating or drying the printing surface or the back surface of the recording medium as the printing object, and examples thereof include infrared heaters, warm air heaters, heating rollers, etc. These can be used alone or in combination of two or more.

[0077] There are no particular restrictions on the method of drying the recording medium to be printed, and it can be appropriately selected according to the purpose. For example, there can be cited a method of bringing a heated fluid such as warm air as a drying mechanism into contact with the recording medium to which ink is applied, a method of bringing the recording medium to which ink is applied into contact with a heating component and heating it by heat transfer, a method of heating the recording medium to which ink is applied by irradiating energy rays such as infrared rays or far infrared rays, etc. Heating can be performed before, during, and / or after printing. By heating before or during printing, printing can be performed on the heated medium, and the printed matter can be dried by heating after printing.

[0078] The heating time is not particularly limited as long as the surface temperature of the recording medium can be controlled to a desired temperature, and can be appropriately selected depending on the purpose.

[0079] The heating time is preferably controlled by controlling the conveyance speed of the recording medium to be printed.

[0080] <Ink>

[0081] The ink preferably contains an organic solvent, a resin, and water, and also contains a colorant and an additive. The ink preferably contains an aqueous ink.

[0082] The viscosity of the ink at 25° C. is 9.0 mPa·s to 11.0 mPa·s, preferably 9.0 mPa·s to 10.2 mPa·s. When the viscosity at 25° C. is 9.0 mPa·s to 11.0 mPa·s, continuous ejection stability is improved.

[0083] The viscosity of the ink at 36° C. is 6.5 mPa·s to 11.0 mPa·s, preferably 6.5 mPa·s to 9.0 mPa·s. When the viscosity at 25° C. is 6.5 mPa·s to 11.0 mPa·s, the continuous ejection stability is improved.

[0084] The viscosity of the ink can be measured without any particular limitation and can be appropriately selected depending on the intended purpose. For example, the viscosity can be measured using a rotational viscometer (RE-85, manufactured by Toki Sangyo Co., Ltd.).

[0085] <Organic Solvents>

[0086] There is no particular limitation on the type of the organic solvent, and it can be appropriately selected according to the purpose, and examples thereof include ethers such as polyols, polyol alkyl ethers or polyol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds. These can be used alone or in combination of two or more.

[0087] The polyols are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol, 3-methyl-1,3-butylene glycol, 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, glycerol, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, Petriol, etc.

[0088] The polyol alkyl ethers are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.

[0089] The polyol aryl ethers are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0090] The nitrogen-containing heterocyclic compound is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone.

[0091] The amides are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.

[0092] The amines are not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the amines include monoethanolamine, diethanolamine, and triethylamine.

[0093] The sulfur-containing compounds are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include dimethyl sulfoxide, sulfolane, and thiodiethanol.

[0094] Examples of other organic solvents include propylene carbonate, ethylene carbonate, etc. In order to function as a wetting agent and also to obtain good drying performance, it is preferred to use an organic solvent having a boiling point of 250° C. or less.

[0095] As the organic solvent, polyol compounds and glycol ether compounds having carbon atoms of 8 or more are also preferably used. Specific examples of polyol compounds having carbon atoms of 8 or more include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

[0096] Specific examples of the glycol ether compounds include polyol alkyl ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; and polyol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0097] The boiling point of the organic solvent is not particularly limited and can be appropriately selected according to the purpose, but is preferably 270° C. or higher. By making the ink contain an organic solvent at 270° C. or higher, sufficient fixability to wallpaper and canvas fabrics can be ensured, and drying near the nozzle can be suppressed to reduce ejection failure.

[0098] The content of the organic solvent at 270° C. or higher is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 6% by mass or higher, and more preferably 10% by mass or higher, based on the ink.

[0099] <Resin>

[0100] The resin is not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, acrylic silicon resin, etc. can be mentioned, and resin particles composed of these resins can also be used. Among them, polyurethane resin is preferred.

[0101] As the resin particles, those appropriately synthesized or commercially available may be used. In addition, these may be used alone or in combination of two or more.

[0102] The resin particles may be prepared by mixing a material such as a colorant or an organic solvent in a state of a resin emulsion in which the resin particles are dispersed using water as a dispersion medium.

[0103] The type of the polyurethane resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyether polyurethane resins, polyester polyurethane resins, and polycarbonate polyurethane resins.

[0104] The polyurethane resin is a reaction product of polyisocyanate and polyol, and can be listed as a soft segment composed of a polyol component with weak cohesion and a hard segment composed of a urethane bond with strong cohesion. The soft segment is soft and resistant to deformation of the base material such as stretching or bending. On the other hand, the hard segment has high adhesion to the base material and good wear resistance.

[0105] From the viewpoint of drying properties, the content of the resin is preferably 10% by mass or less based on the ink.

[0106] The volume average particle size of the resin particles is not particularly limited and can be appropriately selected according to the purpose. However, from the perspective of obtaining good fixing properties and high image density, it is preferably 10 nm or more and 1,000 nm or less, more preferably 10 nm or more and 200 nm or less, and particularly preferably 10 nm or more and 100 nm or less.

[0107] The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0108] <Water>

[0109] The content of the water is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or less based on the ink from the viewpoint of ink drying properties and ejection reliability.

[0110] <Color>

[0111] The colorant is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include pigments and dyes.

[0112] As the pigment, an inorganic pigment or an organic pigment can be used. These can be used alone or in combination of two or more. In addition, as the pigment, a mixed crystal can also be used.

[0113] The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. For example, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, gold or silver luster pigments, or metallic pigments may be used.

[0114] The inorganic pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black.

[0115] The carbon black can be produced by a known method such as a contact method, a furnace method, or a thermal method.

[0116] As the above-mentioned organic pigment, azo pigments, polycyclic pigments (such as phthalocyanine pigments, perylene pigments, pyrene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (such as basic dye type chelates, acid dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, it is preferred to use a pigment with good affinity to the solvent. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0117] Specific examples of black pigments include carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, metal pigments such as copper, iron (CI Pigment Black 11), and titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).

[0118] Furthermore, as color, there are CI Pigment Yellow 1,3,12,13,14,17,24,34,35,37,42 (yellow iron oxide), 53,55,74,81,83,95,97,98,100,101,104,108,109,110,117,120,138,150,153,155,180,1 85,213, CI Pigment Orange 5,13,16,17,36,43,51, CI Pigment Red 1,2,3,5,17,22,23,31,38,48:2 (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),104,105,106,108(cadmium red),112,114,122(quinacridone magenta),123,146,149,166,168,170,172,177,178,179,184,185,190,193,202,207,208,209,213 ,219,224,254,264, CI Pigment Violet 1 (Rhodamine Lake), 3,5:1,16,19,23,38, CI Pigment Blue 1,2,15 (Phthalocyanine Blue), 15:1,15:2,15:3,15:4 (Phthalocyanine Blue), 16,17:1,56,60,63, CI Pigment Green 1,4,7,8,10,17,18,36, etc.

[0119] The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes may be used. One of these dyes may be used alone, or two or more of these may be used in combination.

[0120] Examples of the dye include CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Acid Black 1, 2, 24, 94, CI Cover Black 1, 2, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Direct Black 19, 38, 51, 71, 154, 168, 171, 195, CI Reaction Red 14, 32, 55, 79, 249, and CI Reaction Black 3, 4, 35.

[0121] From the viewpoint of good fixing property and ejection stability, the content of the colorant in the ink is preferably 15% by mass or less, and more preferably 10% by mass or less. A colorant content of 0% by mass means that the ink can also be used as a transparent ink containing no colorant.

[0122] Examples of methods for dispersing a pigment to obtain an ink include a method of introducing a hydrophilic functional group into the pigment to make it self-dispersible, a method of dispersing the pigment by coating the surface of the pigment with a resin, and a method of dispersing the pigment using a dispersant.

[0123] As a method of introducing a hydrophilic functional group into a pigment to form a self-dispersible pigment, for example, there is a method of adding a functional group such as a sulfonic acid group or a carboxyl group to a pigment (for example, carbon) to make it dispersible in water.

[0124] As a method of coating the surface of the pigment with a resin and dispersing it, there can be exemplified a method of containing the pigment in a microcapsule and dispersing it in water. This can be said to be resin-coated pigment. In this case, the pigments in the ink do not need to be completely coated with the resin, and uncoated pigments or partially coated pigments can also be dispersed in the ink within the scope that does not affect the effect of the present invention.

[0125] Examples of the method of dispersing using a dispersant include a method of dispersing using a well-known low-molecular-weight dispersant or a high-molecular-weight dispersant represented by a surfactant.

[0126] As the dispersant, it is possible to use one depending on the pigment, and for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant or the like can be used.

[0127] As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fats Co., Ltd. or sodium naphthalenesulfonate formalin condensate can also be suitably used. The dispersant may be used alone or in combination of two or more.

[0128] <Pigment dispersion>

[0129] The ink can be obtained by mixing water or an organic solvent with a pigment. Alternatively, the ink can be produced by mixing water or an organic solvent with a pigment dispersion prepared by mixing a pigment with other water or a dispersant.

[0130] The pigment dispersion can be obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as required, and adjusting the particle size. A disperser can be used for dispersion.

[0131] There is no particular restriction on the particle size of the pigment in the pigment dispersion, but from the viewpoint that the dispersion stability of the pigment is good, the ejection stability, image quality such as image density will also be improved, the maximum frequency converted by the maximum number is preferably 20 nm to 500 nm, more preferably 20 nm to 150 nm. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0132] The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. From the perspective of obtaining good ejection stability and improving image density, it is preferably 0.1 mass % to 50 mass %, and more preferably 0.1 mass % to 30 mass %.

[0133] The pigment dispersion is preferably degassed by filtering out coarse particles with a filter, a centrifugal separator or the like as necessary.

[0134] There is no particular restriction on the particle size of the solid matter in the ink, and it can be appropriately selected according to the purpose. From the viewpoint of improving the image quality such as jetting stability and image density, the maximum frequency of the particle size of the solid matter in the ink is preferably between 20 nm and 1000 nm, and more preferably between 20 nm and 150 nm, in terms of the maximum number. Solids include resin particles and pigment particles, etc. The particle size can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0135] <Additives>

[0136] If necessary, a surfactant, a defoaming agent, a preservative and an antifungal agent, a rust inhibitor, a pH adjuster, etc. may be added to the ink.

[0137] <Surfactant>

[0138] As the surfactant, any of a silicon surfactant, a fluorine surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.

[0139] There are no particular restrictions on the silicone surfactant, and it can be appropriately selected according to the purpose. Among them, preferred are surfactants that do not decompose even at high pH. As silicone surfactants, for example, side chain modified polydimethylsiloxane, two-end modified polydimethylsiloxane, single-end modified polydimethylsiloxane, side chain two-end modified polydimethylsiloxane, etc. can be cited. As the modifying group, there are polyoxyethylene groups and polyoxyethylene polyoxypropylene groups, but preferred are modifying groups that show good properties as water surfactants. In addition, as silicone surfactants, polyether modified silicone surfactants can also be used, for example, compounds in which a polyalkylene oxide structure is introduced into the Si side chain of dimethylsiloxane, etc. can be cited.

[0140] As the fluorinated surfactant, for example, perfluoroalkylsulfonic acid compounds, perfluoroalkylcarboxylic acid compounds, perfluoroalkylphosphate compounds, and polyoxyalkylene ether polymer compounds having a perfluoroalkylethylene oxide adduct and a perfluoroalkylether group in a side chain are particularly preferred because of their low foaming properties.

[0141] As perfluoroalkyl sulfonic acid compounds, for example, perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, etc. can be exemplified. As perfluoroalkyl carboxylic acid compounds, for example, perfluoroalkyl carboxylic acid, perfluoroalkyl carboxylate, etc. can be exemplified. As polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain, sulfate ester salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group in the side chain, salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group in the side chain, etc. can be exemplified. As counterions of the salts in these fluorinated surfactants, Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, NH(CH2CH2OH)3, etc. can be exemplified.

[0142] Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

[0143] Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol.

[0144] Examples of the anionic surfactant include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, polyoxyethylene alkyl ether sulfates, etc. These may be used alone or in combination of two or more.

[0145] There are no particular restrictions on the silicone surfactant, and it can be appropriately selected according to the purpose. For example, side chain modified polydimethylsiloxane, both end modified polydimethylsiloxane, single end modified polydimethylsiloxane, side chain both end modified polydimethylsiloxane, etc. can be mentioned. As the modifying group, polyether modified silicone surfactants having polyoxyethylene groups and polyoxyethylene polyoxypropylene groups are particularly preferred because they show good properties as water surfactants.

[0146] As such a surfactant, a suitably synthesized one or a commercially available one may be used. Commercially available ones may be obtained 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.

[0147] As the above-mentioned polyether-modified silicone surfactant, there is no particular limitation and it can be appropriately selected according to the purpose. As the above-mentioned polyether-modified silicone surfactant, commercially available products can be used, for example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (Nihon 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 Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) etc. can be cited.

[0148] As the fluorine surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferred, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferred.

[0149] Examples of the fluorinated surfactant include perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in a side chain, etc. Among them, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in a side chain are preferred because they have less foaming properties.

[0150] As the above-mentioned fluorine surfactant, commercial products can also be used. As commercial products thereof, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by AGC Co., Ltd.); Fludard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafac F-470, F-1405, F-474 (all manufactured by Megafac Co., Ltd.); Nippon Ink & Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all made by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all made by NEOS Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), etc. Among them, FS-3100, FS-34, FS-300 manufactured by Chemours, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by NEOS Co., Ltd., Polyfox PF-151N manufactured by Omnova and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred from the perspective of good printing quality, especially color rendering, paper penetration, wettability, and significantly improved dyeing levelness.

[0151] The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the purpose. From the viewpoint of good wettability, good ejection stability, and improved image quality, it is preferably 0.001% by mass to 5% by mass, and more preferably 0.05% by mass to 5% by mass.

[0152] <Defoaming agent>

[0153] There are no particular restrictions on the defoamer, and examples thereof include silicon-based defoamers, polyether-based defoamers, fatty acid ester-based defoamers, etc. These can be used alone or in combination of two or more. Among these, silicon-based defoamers are preferred from the perspective of good bubble breaking effect.

[0154] <Anticorrosion and antifungal agent>

[0155] As an antiseptic and mildew-proof agent, there is no particular limitation. For example, 1,2-benzisothiazolin-3-one etc. can be cited.

[0156] <Rust inhibitor>

[0157] As a rust inhibitor, there is no particular limitation. For example, acid sulfite, sodium thiosulfate etc. can be cited.

[0158] <pH adjuster>

[0159] As a pH adjuster, as long as it can adjust the pH to above 7, there is no particular limitation. Amines such as diethanolamine and triethanolamine can be cited.

[0160] As the pH of the ink, from the viewpoint of preventing corrosion of the metal parts in contact with the liquid, it is preferably 7 to 12, more preferably 8 to 11.

[0161] <Printing object>

[0162] As the printing object, it is not limited to the printing object used as a recording medium. For example, building materials such as wallpaper, floor materials, and tiles, cloth for clothing such as T-shirts, textiles, leather, etc. can be appropriately used. In addition, by adjusting the configuration of the path for conveying the recording medium, ceramics, glass, metal, etc. can also be used as the printing object. As the recording medium, there is no particular limitation. Ordinary paper, glossy paper, special paper, cloth, etc. can also be used. Good image formation can be carried out even when using a non-permeable substrate material. A non-permeable substrate material is a substrate material with low water permeability and low absorbency on the surface, and also includes materials that do not open to the outside even if there are many voids inside. More quantitatively, it refers to a substrate material with a water absorption of 10 mL / m2 or less from the start of contact to 30 msec1 / 2 in the Bristow method. As the above non-permeable substrate material, for example, plastic films such as vinyl chloride resin film, polyethylene terephthalate (PET) film, acrylic resin film, polypropylene film, polyethylene film, and polycarbonate film can be suitably used.

[0163] <Recording device, recording method>

[0164] In the following description of the recording device and recording method, although the case of using black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink is described, non-aqueous transparent ink can also be used instead of or in addition to these inks. The non-aqueous transparent ink used in the present invention can be appropriately used in various recording devices of the inkjet recording method, such as printers, fax devices, copying devices, printer / fax / copying multi-function peripherals, three-dimensional modeling devices, etc. Unless otherwise specified, the inkjet recording device also includes any of a serial device that moves the nozzle and a linear device that does not move the nozzle. Furthermore, the inkjet recording device includes not only a desktop recording device, but also a wide-width recording device, for example, a continuous printer that can use continuous paper wound into a roll as a recording medium. In the present invention, the recording device and the recording method refer to a device that can spray ink and various processing liquids on the recording medium, and a method of recording using the device. The recording medium refers to a medium to which ink and various processing liquids can adhere even temporarily. The recording device includes not only the nozzle part that ejects ink, but also the mechanism related to the supply, transportation, and paper discharge of the recording medium, and the device called the pre-processing device, the post-processing device, etc. In addition, the recording device and the recording method are not limited to the recording device and the recording method that visualize meaningful images such as text and graphics through ink. For example, it also includes the formation of patterns such as geometric patterns, and the case of shaping a three-dimensional image. In addition, unless otherwise specified, the inkjet recording device also includes any of a serial device that moves the nozzle and a linear device that does not move the nozzle. Furthermore, in the recording device, not only a desktop recording device is included, but also a wide-width recording device that can print on a recording medium of A0 size, for example, a continuous printer that can use continuous paper wound into a roll as a recording medium.

[0165] Reference Figure 1 to Figure 2 An example of a recording device will be described. Figure 1 Shown is a perspective illustration of a recording device. Figure 2The figure shows a three-dimensional illustration of the main box. The image forming device 400, which is an example of a recording device, is a serial type image forming device. A mechanism unit 420 is provided in the housing 401 of the image forming device 400. Each ink storage unit 411 of the main box 410 (410k, 410c, 410m, 410y) for each color such as black (K), cyan (C), magenta (M), yellow (Y) is formed by a packaging member such as an aluminum laminate film. The ink storage unit 411 is contained in a storage container box 414 made of plastic, for example. Thus, the main box 410 is used as an ink cartridge for each color. On the other hand, an ink cartridge holding component 404 is provided on the inner side of the opening when the cover 401c of the device body is opened. The main box 410 is detachably mounted on the ink cartridge holding component 404. Thus, each ink discharge port 413 of the main tank 410 communicates with the ejection head 434 for each color via the supply hose 436 for each color, and ink can be ejected from the ejection head 434 toward the recording medium.

[0166] In addition, in the terms of the present invention, image formation, recording, printing, printing, etc. are all synonyms. Recording medium, medium, and printing object are all synonyms.

[0167] [Example]

[0168] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0169] (Preparation Example 1 of Polyurethane Resin)

[0170] In a nitrogen-purged container equipped with a thermometer, a nitrogen inlet pipe and a stirrer, 200.4 g of polyester polyol (trade name: Polylite OD-X-2251, manufactured by DIC Corporation, average molecular weight 2000), 15.7 g of 2,2-dimethylol propionic acid, 48.0 g of isophorone diisocyanate, 77.1 g of methyl ethyl ketone as an organic solvent and 0.06 g of DMTDL (dibutyltin dilaurate) as a catalyst were mixed and reacted for 4 hours. Then, 30.7 g of methyl ethyl ketone as a diluent was added, and when the average molecular weight reached the range of 20,000 to 60,000, 1.4 g of methanol was added to terminate the above reaction, thereby obtaining an organic solvent solution of a polyurethane resin.

[0171] To the obtained polyurethane resin organic solvent solution, 13.4 g of a 48% by mass potassium hydroxide aqueous solution and 715.3 g of water were added, and the mixture was sufficiently stirred, and then aged and desolvated, thereby preparing a polyurethane resin A.

[0172] The minimum film-forming temperature (MFT) of the obtained polyurethane resin emulsion A was measured using a film-forming temperature tester (manufactured by Imoto Seisakusho Co., Ltd.) and the result was 74°C.

[0173] (Preparation Example 2 of Polyurethane Resin)

[0174] In a nitrogen-purged container equipped with a thermometer, a nitrogen inlet tube, and a stirrer, 1500 g of polycarbonate (reaction product of 1,6-hexanediol and dimethyl carbonate (number average molecular weight (Mn): 1200)), 220 g of 2,2-dimethylol propionic acid (DMPA), and 1347 g of N-methylpyrrolidone (NMP) were mixed under a nitrogen stream and heated to 60° C. to dissolve DMPA. Then, 1445 g of 4,4'-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurate as a catalyst were added, heated to 90° C., and reacted for 5 hours to obtain an isocyanate-terminated urethane prepolymer. The obtained isocyanate-terminated urethane prepolymer was cooled to 80° C., and 149 g of triethylamine was added and mixed to obtain a mixture. To 4340 g of the obtained mixture were added 5400 g of water, 15 g of triethylamine, 1500 g of ice, and 626 g of a 35% by mass aqueous solution of 2-methyl-1,5-pentanediamine to carry out a chain growth reaction, thereby preparing a polyurethane resin B.

[0175] The minimum film-forming temperature (MFT) of the obtained polyurethane resin emulsion B was measured using a film-forming temperature tester (manufactured by Imoto Seisakusho Co., Ltd.) and the result was 55°C.

[0176] (Manufacturing Example 1 of Black Ink)

[0177] As shown in Table 1 below, 3 parts by weight of a black pigment (carbon black), 0.5 parts by weight of a dispersant (trade name: Pioneer A-51-B, manufactured by Takemoto Oil & Fats Co., Ltd., a polyester compound) and 58.5 parts by weight of diethylene glycol diethyl ether were premixed and then circulated and dispersed in a disc bead mill (manufactured by Shinmaru Enterprises, KDL type, medium: using zirconium oxide balls with a diameter of 0.3 mm) for 3 hours to obtain a black pigment dispersion.

[0178] Next, 18.7 parts by mass of the obtained black pigment dispersion, 17.1 parts by mass of polyurethane resin emulsion A, 20.6 parts by mass of polyurethane resin emulsion B, 0.3 parts by mass of 2-amino-2-ethyl-1,3-propanediol (AEPD, manufactured by Tokyo Chemical Industry Co., Ltd.), 1.2 parts by mass of glycerol, 29.0 parts by mass of isoprene glycol, 0.8 parts by mass of silicone surfactant (trade name: KF-643, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.2 parts by mass of defoamer (trade name: Surfynol AD01, manufactured by Nissin Chemical Industry Co., Ltd.), and 12.1 parts by mass of water were mixed and stirred to prepare a mixture. The obtained mixture was filtered with a polypropylene filter having an average pore size of 0.2 μm (trade name: Betafine polypropylene pleated filter PPG series, manufactured by 3M Company), thereby preparing black ink A.

[0179] The viscosity of the obtained black ink A was measured using a rotation viscometer (RE-85, manufactured by Toki Sangyo Co., Ltd.), and the viscosity at 25° C. was 10.1 mPa·s, and the viscosity at 36° C. was 6.6 mPa·s.

[0180] (Manufacturing Examples 2 to 8 of Black Ink)

[0181] In the black ink manufacturing example 1, black inks B to H were prepared in the same manner as in the black ink manufacturing example 1 except that the ink composition was changed to that shown in Table 1. The viscosity of the obtained black inks B to H was measured in the same manner as in the black ink manufacturing example 1. The measurement results are shown in Table 1.

[0182] Table 1

[0183]

[0184] (Examples 1 to 12 and Comparative Examples 1 to 20)

[0185] Any of the above black inks A to H was introduced into a droplet observation device (EV2500, manufactured by Ricoh Co., Ltd.), and a voltage was applied to the liquid chamber using any of the basic drive waveforms shown in Table 2 to eject droplets. The combinations of the basic drive waveforms and black inks in Examples 1 to 12 and Comparative Examples 1 to 20 are shown in Tables 2 to 4.

[0186] In addition, the natural vibration period Tc in the liquid chamber of the above-mentioned liquid droplet observation device (EV2500, manufactured by Ricoh Co., Ltd.) is 6.0 (μsec).

[0187] Figure 4 The basic driving waveform in Example 1 is shown. Figure 4 P1 is the first driving pulse, and P2 is the second driving pulse. Figure 4 P0 in FIG. 1 is a general driving waveform, not a necessary driving waveform.

[0188] Table 2

[0189]

[0190] Table 3

[0191] Basic driving waveform Black ink Example 1 1 A Example 2 1 D Example 3 1 E Comparative Example 1 1 B Comparative Example 2 1 C Comparative Example 3 1 F Comparative Example 4 1 G Example 4 1 H Comparative Example 5 2 B Comparative Example 6 2 C Comparative Example 7 2 F Comparative Example 8 2 G Comparative Example 9 2 H Comparative Example 10 3 B Comparative Example 11 3 C Comparative Example 12 3 F Comparative Example 13 3 G

[0192] Table 4

[0193] Basic driving waveform Black ink Example 5 3 H Comparative Example 14 4 B Comparative Example 15 4 C Comparative Example 16 4 F Comparative Example 17 4 G Example 6 4 H Comparative Example 18 2 A Comparative Example 19 2 D Comparative Example 20 2 E Example 7 3 A Example 8 3 D Example 9 3 E Example 10 4 A Embodiment 11 4 D Example 12 4 E

[0194] For Examples 1 to 12 and Comparative Examples 1 to 20, "ligament length", "continuous ejection stability" and "variation in droplet velocity" were evaluated based on the following evaluation method. The results are shown in Tables 5 and 6.

[0195] <Ligament length>

[0196] For Examples 1 to 12 and Comparative Examples 1 to 20, the time from the main droplet passing through to the rear end of the satellite droplet passing through at a point 2 mm from the nozzle surface was measured using EV2500 (manufactured by Ricoh Co., Ltd.), and the ligament length was evaluated based on the following evaluation criteria. "△" or above means practical.

[0197] (Evaluation Criteria)

[0198] ○: No satellite

[0199] △: There is a satellite droplet, and the time it takes for the rear end of the satellite droplet to pass is less than 20μs

[0200] ×: There is a satellite droplet, and the time it takes for the rear end of the satellite droplet to pass is more than 20 μs

[0201] <Continuous injection stability>

[0202] For Examples 1 to 12 and Comparative Examples 1 to 20, the ratio of nozzle holes that continued to eject droplets after ejecting droplets for 1 hour was measured, and the continuous ejection stability was evaluated based on the following evaluation criteria: "△" or above means practical.

[0203] (Evaluation Criteria)

[0204] ○: The ratio of the nozzle holes that continue to spray is 100% △: The ratio of the nozzle holes that continue to spray is 90% or more and less than 100% ×: The ratio of the nozzle holes that continue to spray is less than 90%

[0205] <Changes in Droplet Velocity>

[0206] exist Figure 4In the basic driving waveform shown, under the following conditions (i), (ii) and (iii), the time Tj from the main droplet passing through the point a at a certain distance from the nozzle surface is measured, and the maximum difference (ΔTj) among the differences in Tj under the following conditions (i), (ii) and (iii) is used to evaluate the change in droplet velocity based on the following evaluation criteria. "○" means practical.

[0207] (i) Ejection is performed using a driving waveform including only P1.

[0208] (ii) Ejection is performed using a driving waveform including P0 and P1.

[0209] (iii) Ejection is performed using a driving waveform including P0, P1, and P2.

[0210] (Evaluation Criteria)

[0211] ○: ΔTj<20

[0212] ×:ΔTj≥20

[0213] Table 5

[0214]

[0215] Table 6

[0216]

[0217] As embodiments of the present invention, for example, the following are described.

[0218] <1>

[0219] An inkjet recording device is used, which includes a nozzle plate having nozzles for ejecting ink containing resin, organic solvent and water, a liquid chamber connected to the nozzle, and a nozzle head having a pressure generating mechanism for generating pressure in the liquid chamber,

[0220] The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink.

[0221] The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C.,

[0222] The inkjet recording method is characterized by satisfying the following conditions (1) and (2):

[0223] (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element.

[0224] (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus on the nozzle surface without ejecting the ink.

[0225] <2>

[0226] according to <1> In the inkjet recording method, the second driving pulse is applied within 1 / 2 of the natural vibration period of the liquid chamber after the first driving pulse starts to eject the liquid droplets.

[0227] <3>

[0228] according to <1> In the inkjet recording method, the second driving pulse is applied at a frequency not less than 1 / 2 and not more than 1 of the natural vibration period of the liquid chamber after the first driving pulse starts ejecting the liquid droplets.

[0229] <4>

[0230] according to <1> ~ <3> In any one of the inkjet recording methods, the pressure generating mechanism is a piezoelectric element.

[0231] <5>

[0232] according to <1> ~ <4> In any one of the inkjet recording methods, the content of the resin is 10% by mass or more based on the ink.

[0233] <6>

[0234] according to <1> ~ <5> The inkjet recording method according to any one of the preceding claims: the ink contains at least one polyurethane resin.

[0235] <7>

[0236] An inkjet recording device, comprising:

[0237] Ink, containing resin, organic solvent and water, and

[0238] The ejection head includes a nozzle plate having nozzles for ejecting the ink, a liquid chamber connected to the nozzles, and a pressure generating mechanism for generating pressure in the liquid chamber.

[0239] The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink,

[0240] The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C.,

[0241] The following conditions (1) and (2) are met:

[0242] (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element;

[0243] (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus of the nozzle surface without ejecting the ink.

[0244] According to the above <1> ~ <6> The inkjet recording method described in any one of the above <7> The inkjet recording device can solve the above-mentioned various problems in the past and achieve the above-mentioned purpose of the present invention.

Claims

1. An inkjet recording method using an inkjet recording device having an ejection head, the ejection head comprising a nozzle plate having nozzles for ejecting ink containing a resin, an organic solvent and water, a liquid chamber connected to the nozzle, and a pressure generating mechanism for generating pressure in the liquid chamber, The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink, The inkjet recording method is characterized in that: The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C., The inkjet recording method satisfies the following conditions (1) and (2): (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element; (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus of the nozzle surface without ejecting the ink.

2. The inkjet recording method according to claim 1, characterized in that: From the start of ink ejection by the first drive pulse, the second drive pulse is applied at a period not greater than 1 / 2 of the natural vibration period of the liquid chamber.

3. The inkjet recording method according to claim 1, characterized in that: After the ejection of ink by the first drive pulse is started, the second drive pulse is applied at a period not less than 1 / 2 and not more than 1 of the natural vibration period of the liquid chamber.

4. The inkjet recording method according to any one of claims 1 to 3, characterized in that: The pressure generating mechanism is a piezoelectric element.

5. The inkjet recording method according to any one of claims 1 to 3, characterized in that: The content of the resin is 10% by mass or more.

6. The inkjet recording method according to any one of claims 1 to 3, characterized in that: The resin contains a polyurethane resin.

7. An inkjet recording device comprising: Ink, containing resin, organic solvent and water, and The ejection head includes a nozzle plate having nozzles for ejecting the ink, a liquid chamber communicating with the nozzles, and a pressure generating mechanism for generating pressure in the liquid chamber. The pressure generating mechanism applies a first driving pulse and a second driving pulse to eject ink, The inkjet recording device is characterized in that: The ink has a viscosity of 9.0 mPa·s or more and 11.0 mPa·s or less at 25° C., and a viscosity of 6.5 mPa·s or more and 11.0 mPa·s or less at 36° C., Satisfy the following conditions (1) and (2): (1) The first drive pulse includes a first waveform element in which a voltage exceeding the reference voltage is applied after a voltage less than a reference voltage is applied, and a second waveform element in which a voltage less than the reference voltage is applied after the first waveform element; (2) The second driving pulse includes a third waveform element for pulling in and pushing out the meniscus of the nozzle surface without ejecting the ink.

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