Active energy ray-curable aqueous ink, recording method, and recording device

Abstract

To provide an active energy ray-curable aqueous ink which is good in both water solubility of a monomer and water resistance of a cured product when used as an aqueous ink.SOLUTION: The active energy ray-curable aqueous ink contains water and a curable substance and can be cured with an active energy ray. The curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1). (In the general formula (1), R1 represents a hydrogen atom or a methyl group; R2 represents a C1-5 divalent saturated hydrocarbon group; and L represents a divalent saturated hydrocarbon group optionally containing an ether bond, an amide bond, a carbonyl bond, a sulfone bond or a sulfonamide bond.)SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an active energy ray-curable aqueous ink containing a water-soluble monomer. Further, the present invention relates to a recording method and a recording apparatus using the active energy ray-curable aqueous ink.

Background Art

[0002] Conventionally, in an inkjet image forming method, a technique of using an active energy ray-curable liquid composition as ink is known. When using an active energy ray-curable liquid composition as ink, it is known to use a non-aqueous curable substance or an aqueous curable substance.

[0003] As an example of ink using a non-aqueous curable substance, in Patent Document 1, a method of suppressing the odor of ink by using an acrylate compound having an amide structure on the ester side has been proposed.

[0004] Further, as an example of ink using an aqueous curable substance, a curable aqueous ink containing water, a monomer·oligomer, and a pigment dispersion can be mentioned. Monomers and oligomers used in curable aqueous inks are required to have good water solubility and stability in an aqueous solution. In Patent Document 2, a method of making an ink composition have good water solubility by using an acrylamide compound having a specific structure has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The acrylic acid ester compound described in Patent Document 1 suppresses odor by using a monofunctional monomer having an amide bond in the ester structure. However, this acrylic acid ester compound is intended for use in non-aqueous inks. Therefore, if this acrylic acid ester compound is used in an aqueous ink, it is conceivable that the hydrolysis of the acrylic acid ester bond, as described in Japanese Patent Application Publication No. 2007-099802, may cause problems with the stability of the ink.

[0007] On the other hand, the acrylamide structure compound described in Patent Document 2 has good water solubility. However, because this compound has high water solubility in its monomer form, there are issues with the water resistance of the cured product.

[0008] Therefore, an object of the present invention is to provide an active energy ray-curable aqueous ink that contains monomers with excellent water solubility and also has excellent water resistance when cured. Another object of the present invention is to provide a recording method and a recording apparatus using the active energy ray-curable aqueous ink. [Means for solving the problem]

[0009] The aqueous ink according to the present invention is an active energy ray curable aqueous ink that contains water and a curable substance and can be cured by active energy rays, The present invention relates to an active energy ray-curable aqueous ink characterized in that the curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1).

[0010] [ka]

[0011] In the general formula (1) above, R1 represents a hydrogen atom or a methyl group, and R2 represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms. L is a divalent saturated hydrocarbon group which may include an ether bond, amide bond, carbonyl bond, sulfone bond, or sulfonamide bond.

[0012] The present invention also includes a step of applying an active energy ray-curable aqueous ink onto a recording medium, a step of irradiating the active energy ray-curable aqueous ink applied onto the recording medium with active energy rays, and is a recording method having at least the above steps, where the active energy ray-curable aqueous ink contains water and a curable substance and is curable by active energy rays, and relates to a recording method characterized in that the curable substance contains a bifunctional polymerizable monomer represented by the above general formula (1).

[0013] Furthermore, the present invention includes an ink application device for applying an active energy ray-curable aqueous ink onto a recording medium, an active energy ray irradiation device for irradiating the active energy ray-curable aqueous ink applied onto the recording medium with active energy rays, and is a recording device having at least the above components, where the active energy ray-curable aqueous ink contains water and a curable substance and is curable by active energy rays, and relates to a recording device characterized in that the curable substance contains a bifunctional polymerizable monomer represented by the above general formula (1).

Advantages of the Invention

[0014] According to the present invention, it is possible to provide an active energy ray-curable aqueous ink that contains a monomer excellent in water solubility and is also excellent in water resistance when formed into a cured product. In addition, it is possible to provide a recording method and a recording device using the active energy ray-curable aqueous ink.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic perspective view showing the configuration of an inkjet recording device in one embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0016] <Water-based ink> The water-based ink according to the present invention contains water and a curable substance, and is an active energy ray-curable water-based ink that can be cured by active energy rays. Hereinafter, the present invention will be described in detail with reference to preferred embodiments. (Curable substance) The active energy ray-curable water-based ink according to the present invention contains water and a curable substance. The curable substance includes a bifunctional polymerizable monomer represented by the following general formula (1). And this active energy ray-curable water-based ink can be cured by active energy rays. Hereinafter, the active energy ray-curable water-based ink is simply referred to as a water-based ink.

[0017]

Chemical formula

[0018] In the general formula (1), R1 represents a hydrogen atom or a methyl group, and R2 represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms. L is a divalent saturated hydrocarbon group that may contain an ether bond, an amide bond, a carbonyl bond, a sulfone bond, or a sulfonamide bond.

[0019] From the viewpoints of the storage stability of the water-based ink containing the monomer and the curing characteristics of the water-based ink, a polymerizable monomer having an acrylamide group as a functional group and in which R1 in the general formula (1) is hydrogen is particularly preferable.

[0020] Also, R2 in the general formula (1) is not limited as long as it is a divalent saturated hydrocarbon group having 1 to 5 carbon atoms. From the viewpoint of achieving both the water solubility of the monomer and the water resistance of the cured product, it is particularly preferable that it is a divalent saturated hydrocarbon group having 2 to 4 carbon atoms. Specifically, an ethylene group, a propylene group, an isopropylene group, a butylene group, an isobutylene group, etc. can be mentioned.

[0021] Furthermore, L in general formula (1) is not limited to any divalent saturated hydrocarbon group that may contain an ether bond (-O-), an amide bond (-C(=O)-NH-), a carbonyl bond (-C(=O)-), a sulfone bond (-SO2-), or a sulfonamide bond (-SO2-NH-). Here, a divalent saturated hydrocarbon group that may contain each of the aforementioned bonds means a functional group in which at least one carbon atom in the divalent saturated hydrocarbon group is replaced by an ether bond, an amide bond, a carbonyl bond, a sulfone bond, or a sulfonamide bond. From the viewpoint of improving the water solubility of the monomer, it is preferable that L is a divalent saturated hydrocarbon group containing at least one bond selected from the group consisting of ether bonds, amide bonds, carbonyl bonds, sulfone bonds, and sulfonamide bonds. Here, a bifunctional polymerizable monomer in which L is a divalent saturated hydrocarbon group containing these bonds is called the first polymerizable monomer, and a bifunctional polymerizable monomer in which L is a divalent saturated hydrocarbon group that does not have these bonds is called the second polymerizable monomer. For the first polymerizable monomer, it is more preferable that L is a divalent saturated hydrocarbon group containing an ether bond, and it is particularly preferable that it contains an oxyalkylene group such as an oxyethylene group, an oxypropylene group, or an oxybutylene group. Furthermore, each divalent saturated hydrocarbon group containing at least one bond selected from the group consisting of ether bonds, amide bonds, carbonyl bonds, sulfone bonds, and sulfonamide bonds can contain multiple repeating units, each containing one of the above bonds. From the viewpoint of the water resistance of the cured product, the number of repeating units containing the above bonds is preferably 1 to 10, and more preferably 1 to 5. When an oxyalkylene group is included, the number of repetitions is preferably 1 to 5 from the viewpoint of the water resistance of the cured product.

[0022] Furthermore, from the viewpoint of achieving both water solubility of the monomer and water resistance of the cured product, it is preferable that the curable substance contains both a first polymerizable monomer and a second polymerizable monomer. The content of the first polymerizable monomer in the ink is preferably 10% by mass or more and 90% by mass or less, and more preferably 25% by mass or more and 75% by mass or less, based on the total content of the first polymerizable monomer and the second polymerizable monomer in the ink. Table 1 below shows specific structures of difunctional polymerizable monomers represented by general formula (1), but the difunctional polymerizable monomers represented by general formula (1) are not limited to these structures.

[0023] [Table 1-1]

[0024] [Table 1-2]

[0025] The content of the curable substance containing the difunctional polymerizable monomer of general formula (1) is not particularly limited, but from the viewpoint of ejection performance when used in an inkjet system, it is preferably 50% by mass or less, and more preferably 30% by mass or less, relative to the total amount of aqueous ink. Furthermore, from the viewpoint of uniform gloss of the image, it is also preferable to have a content of 20% by mass or less. On the other hand, from the viewpoint of the stability of the cured product, the content of the curable substance containing the difunctional polymerizable monomer of general formula (1) is preferably 5% by mass or more, and more preferably 10% by mass or more, relative to the total amount of aqueous ink.

[0026] The method for synthesizing the difunctional polymerizable monomer of general formula (1) is not particularly limited, but examples include a condensation reaction of an amine compound with (meth)acrylic acid chloride, (meth)acrylic anhydride, or (meth)acrylic acid, or an exchange reaction of an amine compound with an ester compound. In this invention, "(meth)acrylic acid" means "acrylic acid" or "methacrylic acid." The same applies to "(meth)acrylamide," etc.

[0027] The active energy ray-curable aqueous ink of the present invention may optionally contain a combination of multiple difunctional polymerizable monomers represented by the general formula (1). Furthermore, within the limits that do not impair the effects of the present invention, monomers other than those represented by the general formula (1) may be included as curable substances. The monomers other than those represented by the general formula (1) can be monomers that can polymerize with the difunctional polymerizable monomer represented by the general formula (1), and vinyl monomers having similar reactivity are preferred. For example, monofunctional monomers include acroylmorpholine, N-vinylpyrrolidone, acrylamide, hydroxyethylacrylamide, monoacrylic acid esters of oligoethylene oxides, and monoacrylic acid esters of dibasic acids. Polyfunctional monomers include methylenebisacrylamide, ethylenebisacrylamide, 1,2-dihydroxyethylenebisacrylamide, and polyfunctional acrylamides. Commercially available polyfunctional monomers include FOM-03006 (water-soluble tetrafunctional acrylamide), FOM-03007 (water-soluble trifunctional acrylamide), and FOM-03009 (water-soluble tetrafunctional acrylamide) (all trade names, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Monomers that do not fall under the above general formula (1) also preferably have one or more (meth)acrylamide groups, particularly acrylamide groups, as functional groups. Furthermore, it is preferable that the aqueous ink contains monofunctional monomers together with the difunctional monomer represented by formula (1). This can further improve the water solubility of the difunctional monomer represented by formula (1).

[0028] When a monomer other than the one specified in general formula (1) is included, the proportion of the difunctional polymerizable monomer of general formula (1) is preferably 5% by mass or more and less than 100% by mass, more preferably 10% by mass or more and 90% by mass or less, and even more preferably 20% by mass or more and 80% by mass or less, based on the total amount of the curable material. The effects of the present invention are fully exhibited when the proportion of the difunctional polymerizable monomer of general formula (1) is 5% by mass or more, based on the total amount of the curable material.

[0029] Furthermore, if the curable substance contains 50% by mass or more of monofunctional monomers that do not fall under the general formula (1) relative to the total amount of the curable substance, it is preferable that the proportion of the difunctional polymerizable monomer of the general formula (1) be 25% by mass or more relative to the total amount of the curable substance. If the proportion of the difunctional polymerizable monomer of the general formula (1) is 25% by mass or more relative to the total amount of the curable substance, sufficient water resistance can be imparted to the cured product.

[0030] Furthermore, when the curable substance contains 10% by mass or more of a bifunctional or polyfunctional monomer that does not correspond to the general formula (1) relative to the total amount of the curable substance, the proportion of the bifunctional polymerizable monomer of the general formula (1) is preferably 25% by mass or more, and more preferably 40% by mass or more, relative to the total amount of bifunctional or polyfunctional monomers that do not correspond to the general formula (1). When the proportion of the bifunctional polymerizable monomer of the general formula (1) is 25% by mass or more relative to the total amount of bifunctional or polyfunctional monomers that do not correspond to the general formula (1), cracking of the cured product can be suppressed.

[0031] (Polymerization initiator) The aqueous ink according to the present invention preferably further contains a polymerization initiator. The polymerization initiator is not particularly limited as long as it generates an active species that initiates polymerization of the curable substance upon irradiation with active energy rays. Since the curing reaction of the curable substance of the present invention proceeds by radicals, a polymerization initiator that generates radicals is preferred.

[0032] When used as an aqueous ink, the structure of the polymerization initiator preferably has hydrophilic functional groups. Examples of hydrophilic functional groups include hydroxyl groups, carboxylic acid groups, sulfonic acid groups, phosphate groups, carboxylic acid bases, sulfonic acid bases, phosphate bases, ether groups, and amide groups. Preferred examples of polymerization initiators include the following compounds A to C, but the polymerization initiators of the present invention are not limited to these.

[0033] [ka]

[0034] The polymerization initiator may be a combination of two or more types, if necessary. Alternatively, a polymerization initiator may be combined with a sensitizer. By combining two or more polymerization initiators, or a polymerization initiator with a sensitizer, it is possible to generate further radicals by utilizing active energy rays at wavelengths that could not be effectively used with a single polymerization initiator.

[0035] The polymerization initiator content is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.01 to 10% by mass, and even more preferably in the range of 0.01 to 5% by mass, relative to the total amount (100% by mass) of the aqueous ink. If the polymerization initiator content is too high, unreacted polymerization initiator may remain in the cured product, which may reduce the strength of the cured product.

[0036] (Colorants) The aqueous ink according to the present invention may contain a colorant as needed. The colorant is not particularly limited, and dyes, pigments, and dispersions thereof are generally preferred. Furthermore, water-based inks that do not contain colorants are commonly referred to as clear inks and can be used for purposes such as adding gloss to a separately printed surface.

[0037] There are no restrictions on the dyes used; any commonly used dyes can be used without any problems. Examples include CI Direct Blue 6, 8, 22, 34, 70, 71, 76, 78, 86, 142, 199; CI Acid Blue 9, 22, 40, 59, 93, 102, 104, 117, 120, 167, 229; CI Direct Red 1, 4, 17, 28, 83, 227; and CI Acid Red 1, 4, 8, 13, 14, 15, 18, 21, 26. Examples include 35, 37, 249, 257, 289, CI Direct Yellow 12, 24, 26, 86, 98, 132, 142, CI Acid Yellow 1, 3, 4, 7, 11, 12, 13, 14, 19, 23, 25, 34, 44, 71, CI Food Black 1, 2, CI Acid Black 2, 7, 24, 26, 31, 52, 112, 118, etc.

[0038] There are no restrictions on the pigments used; any commonly used pigments can be used without any problems. Examples include CI Pigment Blue 1, 2, 3, 15: 3, 16, 22; CI Pigment Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 112, 122; CI Pigment Yellow 1, 2, 3, 13, 16, 83; Carbon Black No. 2300, 900, 33, 40, 52; MA7, 8, MCF88 (Mitsubishi Chemical Corporation); RAVEN 1255 (Columbia Chemicals); REGAL 330R, 660R; MOGUL (Cabot Chemicals); Color Black FW1, FW18, S170, S150; Printex 35 (Degussa).

[0039] When using such colorants, it is preferable to include a dispersion resin that disperses the dye and pigment in water. The dispersion resin is preferably water-soluble and has a weight-average molecular weight of approximately 1,000 to 15,000. Examples include block copolymers, random copolymers, or salts thereof, composed of the following monomers. • Styrene and its derivatives Vinyl naphthalene and its derivatives • Aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids Acrylic acid and its derivatives • Maleic acid and its derivatives Itaconic acid and its derivatives Fumaric acid and its derivatives

[0040] Furthermore, the material can be dispersed using the aforementioned curable substance without using a dispersion resin.

[0041] Furthermore, the present invention is not limited to the form of ink, and can be used in any form, such as self-dispersing type, resin-dispersed type, or microcapsule type.

[0042] (solvent) The aqueous ink according to the present invention contains at least water as a solvent, and may optionally contain an organic solvent to control ink-applying properties and drying properties. The organic solvent used is preferably a water-soluble material with a high boiling point and low vapor pressure. Examples include polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and glycerin. In addition, alcohols such as ethyl alcohol and isopropyl alcohol, and various surfactants can be added as components to adjust viscosity, surface tension, etc.

[0043] The amount of water-containing solvent is selected appropriately depending on the application, but is preferably 10% by mass or more relative to the total amount of aqueous ink, and is particularly preferably 30% by mass or more, and more preferably 50% by mass or more, when applicable to inkjet recording methods. There is no particular upper limit to the amount of water-containing solvent, but is preferably 90% by mass or less, and more preferably 80% by mass or less, relative to the total amount of aqueous ink. Furthermore, the water content is preferably 10% by mass or more, more preferably 30% by mass or more, and more preferably 50% by mass or more, relative to the total amount of aqueous ink. There is no particular upper limit to the water content, but is preferably 90% by mass or less, and more preferably 80% by mass or less, relative to the total amount of aqueous ink. Furthermore, the water-based ink may contain surfactants, curing accelerators, crosslinking agents, water-soluble additives, viscosity modifiers, etc. The surfactants, etc., mentioned above can be appropriately selected from known sources.

[0044] <Recording Method and Recording Device> The aqueous ink of the present invention can be applied to various known recording methods such as inkjet, gravure, and flexographic methods, but it provides particularly excellent results when applied to inkjet recording methods. The recording method according to the present invention comprises at least the steps of: applying the above-described active energy ray-curable aqueous ink according to the present invention onto a recording medium; and irradiating the active energy ray-curable aqueous ink applied to the recording medium with active energy rays. In particular, the step of applying the ink may be any recording method capable of applying the aqueous ink according to the present invention to the recording medium, such as an inkjet method, gravure method, or flexographic method, but it is preferable to perform the step using an inkjet recording method. (Recording medium) Any medium can be used as the recording medium, as long as it can hold the aqueous ink according to the present invention. In particular, thin media such as sheets or films are preferred for inkjet recording methods. Furthermore, the recording medium can be applied to various absorbent media, such as absorbent media such as paper that can absorb the applied ink, poorly absorbent media such as glossy paper for offset printing, and non-absorbent media such as PET, PC, PVC, and PMMA.

[0045] The recording device according to the present invention comprises at least an ink application device for applying the above-described active energy ray-curable aqueous ink according to the present invention onto a recording medium, and an active energy ray irradiation device for irradiating the active energy ray-curable aqueous ink applied to the recording medium with active energy rays. The ink application device may be any recording method capable of applying the aqueous ink according to the present invention to a recording medium. Preferably, it includes a recording head that ejects ink using an inkjet recording method. As the inkjet recording method, a method that ejects ink by applying thermal energy is preferred, as it allows for easy realization of high-density multi-orifice recording of the recording head and enables high-resolution and high-quality image recording at high speed.

[0046] As a recording head that ejects ink by applying thermal energy, it is preferable to adopt the basic principles disclosed in, for example, U.S. Patent No. 4,723,129 and U.S. Patent No. 4,740,796. Such a system is applicable to both so-called on-demand and continuous types. In the case of an on-demand type, it is preferable to apply at least one drive signal to an electrothermal converter positioned in accordance with the sheet or liquid channel holding the ink, which corresponds to the recording information and gives a rapid temperature rise exceeding nuclear boiling. This generates thermal energy in the electrothermal converter and causes film boiling on the thermal surface of the recording head. As a result, it is effective because it can correspond one-to-one with the drive signal and form bubbles in the ink.

[0047] The growth and contraction of bubbles causes ink to be ejected from the nozzle, forming at least one droplet. If this drive signal is pulsed, the bubbles can grow and contract immediately and appropriately. Therefore, ink can be ejected with particularly good responsiveness, which is preferable. Suitable pulsed drive signals are those described in U.S. Patent No. 4,463,359 and No. 4,345,262. Furthermore, it is preferable to adopt the conditions regarding the rate of temperature rise of the thermally acting surface described in U.S. Patent No. 4,313,124.

[0048] Suitable recording head configurations include those disclosed in the above-mentioned specifications, which consist of a combination of an outlet, a liquid channel, and an electrothermal converter (linear or right-angle liquid channel). Other suitable configurations include those disclosed in U.S. Patent No. 4,558,333 and U.S. Patent No. 4,459,600, which involve the thermal working section being located in a bent region. Furthermore, the atmospheric discharge method described in Japanese Patent No. 2962880, Japanese Patent No. 3246949, and Japanese Patent Application Publication No. 11-188870 is also effective. Additionally, configurations where a common outlet serves as the discharge section of the electrothermal converter (e.g., Japanese Patent Application Publication No. 59-123670) are also effective.

[0049] The following can be used as a full-line type recording head having a length corresponding to the maximum width of the recording medium that the recording device can record on. For example, it may be a configuration that satisfies the length by combining multiple recording heads as disclosed in the above specification, or a configuration as a single recording head formed integrally. Furthermore, interchangeable chip-type recording heads that can be attached to the recording device to enable electrical connection with the device body and ink supply from the device body, and cartridge-type recording heads that are integrally provided with the recording head are also effective.

[0050] It is also preferable to add means for recovering the recording head or auxiliary means. Specifically, these include means for capping the recording head, cleaning means, pressurizing or suction means, electrothermal converter, heating element, preheating means, and pre-discharge mode.

[0051] Figure 1 is a schematic perspective view showing one embodiment of the configuration of an inkjet recording device. The inkjet recording device shown in Figure 1 is a recording device that employs a shuttle system, using a short serial head and recording while scanning the head in the width direction of the recording medium. The carriage 100 is connected to an endless belt 101 and is movable along the guide shaft 102. The endless belt 101 is stretched between pulleys 103 and 104. The drive shaft of the motor 105 is connected to the pulley 103. Therefore, the carriage 100 reciprocates along the guide shaft 102 in the main scanning direction indicated by arrow A by the rotational drive of the motor 105.

[0052] The carriage 100 is equipped with a recording head (not shown) having multiple ink ejection nozzles arranged in parallel, and an ink tank IT which serves as a container for storing ink. An active energy ray irradiation unit 20 is provided at least one end of the carriage 100 in the main scanning direction indicated by arrow A. Therefore, it is possible to irradiate the recording surface with active energy rays from the active energy ray irradiation unit 20 immediately after ink is applied to the recording medium. Examples of active energy rays include electron beams, ultraviolet rays, alpha rays, beta rays, gamma rays, and X-rays. Ultraviolet rays are particularly preferred. This active energy ray irradiation unit 20 is an active energy ray irradiation device that irradiates the ink applied to the recording medium with active energy rays. In Figure 1, active energy ray irradiation units 20 are provided at both ends of the carriage 100. Active energy ray irradiation may be performed immediately after ink application, as shown in the figure, or it may be performed at a certain interval after ink application. Furthermore, it is not limited to a single irradiation, but may be irradiated in multiple stages.

[0053] The recording head has multiple ink ejection ports formed on the ejection port surface facing the paper P, which serves as the recording medium, arranged in the direction of transport of the paper P (the sub-scanning direction of arrow B). The recording head is provided with ink paths that communicate with each of the multiple ejection ports. Corresponding to each ink path, an electrothermal converter is provided to generate thermal energy for ejecting the ink.

[0054] The electrothermal converter generates heat when electrical pulses corresponding to the drive data are applied. This heat causes film boiling in the ink, and as bubbles are generated, the ink is ejected from the nozzle. Each ink path is connected to a common liquid chamber, which is connected to the ink tank IT.

[0055] The inkjet recording device shown in Figure 1 is equipped with a linear encoder 106 for detecting the movement position of the carriage 100. Specifically, a linear scale 107 provided along the direction of movement of the carriage 100 has, for example, 1,200 slits formed at equal intervals over a one-inch period. On the carriage 100 side, for example, a slit detection system 108 having a light-emitting unit and a light-receiving sensor, and a signal processing circuit are provided. Therefore, the linear encoder 106 outputs an ejection timing signal indicating the ink ejection timing, and information on the movement position of the carriage 100, in accordance with the movement of the carriage 100. By ejecting ink each time a slit on the linear scale 107 is detected, an image with a resolution of 1,200 dpi can be recorded in the main scanning direction.

[0056] The paper P, which serves as the recording medium, is intermittently transported in the sub-scanning direction indicated by arrow B, which is perpendicular to the operating direction of the carriage 100. The paper P is supported by a pair of roller units 109 and 110 on the upstream side of the transport direction and a pair of roller units 111 and 112 on the downstream side of the transport direction. A constant tension is applied, and the paper is transported while ensuring flatness relative to the recording head. The driving force for roller units 111 and 112 is supplied from a paper transport motor (not shown).

[0057] In the inkjet recording device shown in Figure 1, an image can be recorded on the entire sheet of paper P by moving the carriage 100 and alternately repeating the recording of a width corresponding to the arrangement width of the recording head's ejection ports and feeding the paper P. The carriage 100 stops at the home position as needed at the start of recording or during recording. At this home position, a cap member 113 is provided that caps the ejection surface side of each recording head. A suction recovery means (not shown) is connected to this cap member 113 to forcibly absorb ink from the ejection port and prevent clogging of the ejection port.

[0058] In addition to the shuttle method described above, there is also a line method that uses a line head in which recording elements are arranged to cover the entire area of ​​one side of the recording medium. In the line method, the recording medium is scanned in a direction perpendicular to the direction of the arrangement of recording elements, allowing image recording to be performed across the entire surface of the recording medium. Therefore, a transport system such as a carriage that scans the short head is unnecessary. Furthermore, complex scanning control between the movement of the carriage and the recording medium is unnecessary, and only the recording medium moves, so the recording speed can be increased compared to the shuttle method. [Examples]

[0059] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples, unless it exceeds the scope of its essence.

[0060] The examples of the present invention used curable substances 1-4 and 12 shown in Table 2 as bifunctional polymerizable monomers. The comparative examples used comparative compounds 1 and 2 shown in Table 2 as bifunctional polymerizable monomers. Furthermore, other monomers that do not fall under the above general formula (1) and are mixed with aqueous ink are shown in Table 3. Comparative compound 1 listed in Table 2 is trade name: FOM-3008 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Monofunctional monomer 1 listed in Table 3 is trade name: HEAA (manufactured by KJ Chemicals Co., Ltd.), monofunctional monomer 2 is trade name: ACMO (manufactured by KJ Chemicals Co., Ltd.), monofunctional monomer 3 is trade name: DAAM (manufactured by KJ Chemicals Co., Ltd.), the bifunctional monomer listed in Table 3 is N,N'-ethylenebisacrylamide (manufactured by Tokyo Chemical Industries, Ltd.), and the trifunctional monomer listed in Table 3 is trade name: FOM-03007 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Furthermore, comparative compound 2, listed in Table 2, was synthesized by the following method. [Synthesis Example A: Synthesis Method of Comparative Compound 2] 200 g (1.35 mol) of 1,2-bis(2-aminoethoxy)methane and 4 L of acetonitrile were mixed, and 256 g (2.83 mol) of acrylate chloride was added dropwise while stirring under ice cooling at a temperature of 8°C or below. The temperature was then raised to 20°C and stirred for a further 2 hours. After the reaction was complete, the reaction mixture was filtered. The reaction product separated by filtration was washed with acetonitrile to obtain 176.3 g of comparative compound 2.

[0061] [Table 2]

[0062] [Table 3]

[0063] (Synthesis of curable materials) The synthesis methods for curable substances 1-4 and 12 are shown below.

[0064] [Synthesis Example 1: Method for synthesizing curable substance 1] 35.0 g (0.24 mol) of 3-acrylamidopropanoic acid and 1 L of methanol were mixed. At room temperature (20°C), 14.8 g (0.10 mol) of 1,2-bis(2-aminoethoxy)ethane was added and the mixture was stirred for 30 minutes. 55.0 g (0.20 mol) of 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium chloride (DMT-MM) was added and the mixture was stirred overnight. After the reaction was complete, the reaction mixture was filtered. The obtained filtrate was concentrated and purified by column chromatography to obtain 27.5 g of curable substance 1. Note that 3-acrylamidopropanoic acid was prepared by reacting 3-aminopropanoic acid with acrylate chloride, but this method is not the only one that can be used.

[0065] [Synthesis Example 2: Method for synthesizing curable substance 2] 45.0 g (0.24 mol) of 6-acrylamidohexanoic acid and 1 L of methanol were mixed. At room temperature (20°C), 14.8 g (0.10 mol) of 1,2-bis(2-aminoethoxy)ethane was added and the mixture was stirred for 30 minutes. 55.0 g (0.20 mol) of DMT-MM was added and the mixture was stirred overnight. After the reaction was complete, the reaction mixture was filtered. The obtained filtrate was concentrated and purified by column chromatography to obtain 32.7 g of curable substance 2. Note that 6-acrylamidohexanoic acid was prepared by reacting 6-aminohexanoic acid with acrylate chloride, but this method is not the only one used.

[0066] [Synthesis Example 3: Method for synthesizing curable substance 3] 35.0 g (0.24 mol) of 3-acrylamidopropanoic acid and 1 L of methanol were mixed. 7.4 g (0.10 mol) of 1,3-diaminopropane was added at room temperature (20°C) and the mixture was stirred for 30 minutes. 55.0 g (0.20 mol) of DMT-MM was added and the mixture was stirred overnight. After the reaction was complete, the reaction mixture was filtered. The resulting filtrate was concentrated and purified by column chromatography to obtain 22.9 g of curable substance 3. Note that 3-acrylamidopropanoic acid was prepared by reacting 3-aminopropanoic acid with acrylate chloride, but this method is not the only one used.

[0067] [Synthesis Example 4: Method for synthesizing curable substance 4] 37.7 g (0.24 mol) of 3-acrylamidobutanoic acid and 1 L of methanol were mixed. 7.4 g (0.10 mol) of 1,3-diaminopropane was added at room temperature (20°C), and the mixture was stirred for 30 minutes. 55.0 g (0.20 mol) of DMT-MM was added, and the mixture was stirred overnight. After the reaction was complete, the reaction mixture was filtered. The resulting filtrate was concentrated and purified by column chromatography to obtain 24.6 g of curable substance 4. Note that 3-acrylamidobutanoic acid was prepared by reacting 3-aminobutanoic acid with acrylate chloride, but this method is not the only one used.

[0068] [Synthesis Example 5: Method for synthesizing curable substance 12] 45.0 g (0.24 mol) of 6-acrylamidohexanoic acid and 1 L of methanol were mixed. 6.0 g (0.10 mol) of ethylenediamine was added at room temperature (20°C) and the mixture was stirred for 30 minutes. 55.0 g (0.20 mol) of DMT-MM was added and the mixture was stirred overnight. After the reaction was complete, the reaction mixture was filtered. The resulting filtrate was concentrated and purified by column chromatography to obtain 20.1 g of curable substance 12. Note that 6-acrylamidohexanoic acid was prepared by reacting 6-aminohexanoic acid with acrylate chloride, but this method is not the only one that can be used.

[0069] <Example 1> (Preparation of water-based ink) Aqueous inks were prepared using the curable substances listed in Table 2, with the following compositions. Hardenable substance 1 5% by mass Monofunctional monomer 1 15% by mass Polymerization initiator (compound A) 2% by mass Surfactant "Acetylenel E100" (product name, manufactured by Kawaken Fine Chemical Co., Ltd.) 1% by mass Ion-exchanged water 77% by mass (Preparation of hardened material) The aforementioned water-based ink was applied as a barcoat to PET film (easy-adhesion white PET, manufactured by Teijin Corporation) at a rate of 10 g / m². 2The coating was applied. Subsequently, a UV-LED (product name, L60II, wavelength 395nm, manufactured by Ushio Inc.) was used to measure 1 J / cm². 2 A cured material was created by irradiating the ink with light to harden it.

[0070] <Example 2> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that curable substance 2 was used instead of curable substance 1 as the bifunctional polymerizable monomer.

[0071] <Example 3> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that curable substance 3 was used instead of curable substance 1 as the bifunctional polymerizable monomer.

[0072] <Example 4> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that curable substance 4 was used instead of curable substance 1 as the bifunctional polymerizable monomer.

[0073] <Example 5> An aqueous ink was prepared in the same manner as in Example 1, except that the ink was prepared using 10% by mass of curable substance 1 and 10% by mass of monofunctional monomer 1 as bifunctional polymerizable monomers, and a cured product was produced.

[0074] <Example 6> An aqueous ink was prepared in the same manner as in Example 1, except that 20% by mass of curable substance 1 was prepared as a bifunctional polymerizable monomer, and an ink without monofunctional monomer 1 was prepared, and a cured product was made.

[0075] <Example 7> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that monofunctional monomer 2 was used as the monofunctional monomer.

[0076] <Example 8> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that monofunctional monomer 3 was used as the monofunctional monomer.

[0077] <Example 9> An aqueous ink was prepared and a cured product was made in the same manner as in Example 5, except that the ink was prepared using the difunctional monomers listed in Table 3 instead of monofunctional monomers.

[0078] <Example 10> An aqueous ink was prepared and a cured product was made in the same manner as in Example 5, except that the ink was prepared using the trifunctional monomers listed in Table 3 instead of monofunctional monomers.

[0079] <Example 11> (Preparation of water-based magenta ink) The pigment (CI Pigment Red 122), dispersant (Styrene / Acrylic Acid / Ethyl Acrylate Random Copolymer, Weight-Average Molecular Weight = 3,500, Acid Value = 150 mg KOH / g), and deionized water were mixed and then dispersed using a bead mill. This yielded a magenta pigment dispersion with a pigment solids content of 10% by mass and a pigment:dispersant (mass ratio) of 3:1. Next, the components listed below were mixed and thoroughly stirred, and the mixture was pressure filtered through a pore size 0.5 μm filter to obtain aqueous magenta ink. Magenta pigment dispersion 40% by mass Hardenable substance 1 5% by mass Monofunctional monomer 1 15% by mass Polymerization initiator (compound A) 2% by mass Surfactant "Acetylenel E100" (product name, manufactured by Kawaken Fine Chemical Co., Ltd.) 1% by mass Ion-exchanged water 36% by mass

[0080] (Preparation of hardened material) The aqueous magenta ink prepared in Example 11 was used as the magenta ink in an on-demand inkjet recording device (product name, Pro-10, manufactured by Canon Corporation) that applies thermal energy corresponding to the recording signal to the ink for ejection. A UV-LED irradiation device (product name, M30, manufactured by Ushio Inc., wavelength 395 nm) was mounted adjacent to the recording head of this recording device. Specifically, as shown in Figure 1, the above device was mounted on the carriage 100 as an active energy ray irradiation unit 20. Using this inkjet recording device, a solid image with 100% duty cycle was printed in one pass onto a PET film (easy-adhesion white PET, manufactured by Teijin Corporation) at a rate of 2 J / cm². 2 A cured material was created by irradiating the ink with light to harden it. Using this inkjet recording device, an image recorded under the condition of applying 8 drops of 3.8 ng of ink to a unit area of ​​1 / 600 inch x 1 / 600 inch is defined as having a 100% duty cycle.

[0081] <Example 12> Aqueous magenta ink was prepared in the same manner as in Example 11, except that instead of using 5% by mass of curable substance 1, the ink was prepared using 2% by mass of curable substance 1 and 3% by mass of curable substance 12. A cured product was then prepared in the same manner as in Example 11.

[0082] <Comparative Example 1> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that comparative compound 1 was used instead of curable substance 1 as the bifunctional polymerizable monomer.

[0083] <Comparative Example 2> An aqueous ink was prepared and a cured product was made in the same manner as in Example 1, except that comparative compound 2 was used instead of curable substance 1 as the bifunctional polymerizable monomer.

[0084] <Comparative Example 3> An aqueous magenta ink was prepared in the same manner as in Example 11, except that comparative compound 1 was used instead of curable substance 1 as a bifunctional polymerizable monomer, and a cured product was prepared in the same manner as in Example 11.

[0085] (evaluation) The aqueous inks and cured products prepared under the above conditions were evaluated using the following evaluation method. The evaluation results are shown in the table. In this disclosure, evaluation criteria A to C for each of the evaluation items below are considered acceptable levels, and D is considered an unacceptable level.

[0086] <Water-soluble> When a bifunctional polymerizable monomer is mixed with deionized water at 25°C and observed visually, the concentration at which no insoluble matter is observed is defined as water solubility. Higher water solubility is preferable, and the evaluation criteria are as follows. A: No insoluble matter was observed at 20% by mass. At B: 5% by mass, no insoluble matter was observed. No insoluble matter was observed at C:1 mass%. At D:1 mass%, insoluble matter was observed.

[0087] <Water resistance> 24 hours after preparing the cured material, 0.2 ml of deionized water was dropped onto the cured material, and after 1 minute, a sheet of Silbon paper was placed on top, with a density of 40 g / cm². 2 The Silbon paper was pulled while under load. Visual inspection was performed to see if peeling occurred in the hardened material. Furthermore, visual inspection was performed to see if any staining occurred on the Silbon paper due to friction with the hardened material. The evaluation criteria were as follows: A: Less than 3% of the hardened material was peeled off due to friction, and more than 90% of the surface area of ​​the Silbon paper was completely free of dirt. B: Less than 10% of the hardened material was peeled off due to friction, and more than 70% of the surface area of ​​the Silbon paper was completely free of dirt. C: Less than 30% of the hardened material is peeled off due to friction, and more than 50% of the surface area of ​​the Silbon paper is completely free of dirt. D: More than 30% of the hardened material was peeled off due to friction, and less than 20% of the surface area of ​​the Silbon paper was free of any dirt.

[0088] Table 4 shows the water solubility results for curable substances 1-4 and 12 used in the examples, and comparative compounds 1-2 used in the comparative examples.

[0089] [Table 4]

[0090] Table 5 shows the composition of the aqueous inks and aqueous magenta inks of Examples 1-12 and Comparative Examples 1-3, as well as the results of the water resistance evaluation.

[0091] [Table 5]

[0092] Furthermore, the disclosure of this embodiment includes the following configurations and methods. (Composition 1) An active energy ray curable aqueous ink containing water and a curable substance, which can be cured by active energy rays, An active energy ray-curable aqueous ink characterized in that the curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1).

[0093] [ka]

[0094] In the general formula (1) above, R1 represents a hydrogen atom or a methyl group, R2 represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms, and L is a divalent saturated hydrocarbon group which may include an ether bond, amide bond, carbonyl bond, sulfone bond, or sulfonamide bond. (Configuration 2) The active energy ray curable aqueous ink according to Configuration 1, wherein L is a divalent saturated hydrocarbon group comprising at least one bond selected from the group consisting of ether bonds, amide bonds, carbonyl bonds, sulfone bonds, and sulfonamide bonds, and the number of repeating units comprising the bond is 1 to 5. (Configuration 3) The active energy ray-curable aqueous ink according to Configuration 1 or 2, wherein the content of the solvent containing water is 50% by mass or more relative to the total amount of the active energy ray-curable aqueous ink. (Configuration 4) An active energy ray curable aqueous ink according to any one of Configurations 1 to 3, comprising a polymerization initiator that generates an active species that initiates polymerization of a curable substance upon irradiation with active energy rays. (Composition 5) An active energy ray curable aqueous ink containing a colorant, as described in any one of Compositions 1 to 4. (Configuration 6) The active energy ray curable aqueous ink according to any one of Configurations 1 to 5, wherein the curable substance further contains a monomer that does not correspond to general formula (1), and the ratio of the difunctional polymerizable monomer of general formula (1) to the total amount of the curable substance is 20% by mass or more and 80% by mass or less. (Configuration 7) The active energy ray curable aqueous ink according to Configuration 6, wherein the monomer not corresponding to the general formula (1) is a monomer having one or more (meth)acrylamide groups as functional groups. (Configuration 8) An active energy ray curable aqueous ink according to Configuration 6 or 7, wherein monofunctional monomers that do not fall under the general formula (1) are contained in an amount of 50% by mass or more relative to the total amount of the curable substance, and the ratio of difunctional polymerizable monomers of the general formula (1) to the total amount of the curable substance is 25% by mass or more. (Configuration 9) An active energy ray curable aqueous ink according to Configuration 6 or 7, wherein the monomer not corresponding to General Formula (1) contains 10% by mass or more of a polyfunctional monomer relative to the total amount of curable material, and the ratio of the difunctional polymerizable monomer of General Formula (1) to the total amount of polyfunctional monomer not corresponding to General Formula (1) is 40% by mass or more. (Method 1) A step of applying an active energy ray curable aqueous ink described in any one of the components 1 to 9 onto a recording medium, A step of irradiating the active energy ray-curable aqueous ink applied to the recording medium with active energy rays, A recording method characterized by having at least one of the following. (Method 2) The recording method described in Method 1, wherein the step of applying the ink is performed using an inkjet recording method. (Configuration 10) An ink dispensing device that dispenses an active energy ray curable aqueous ink described in any one of Configurations 1 to 9 onto a recording medium, An active energy ray irradiation device for irradiating the active energy ray-curable aqueous ink applied to the recording medium with active energy rays, A recording device characterized by having at least one of the following. (Configuration 11) The recording device according to Configuration 10, wherein the ink dispensing device comprises a recording head that ejects ink in an inkjet recording manner. [Explanation of symbols]

[0095] 100 Carriage 101 Endless belt 102 Guide shaft 103 Pulley 104 Pulley 105 Motor 106 Linear Encoder 107 Linear Scale 108 Slit detection system 109 Upstream Roller Unit 110 Upstream roller unit 111 Downstream roller unit 112 Downstream Roller Unit 113 Cap member 20 Active energy ray irradiation section IT Ink Tank

Claims

1. An active energy ray-curable water-based ink that contains water and a curable substance and can be cured by active energy rays, The active energy ray-curable water-based ink, wherein the curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1): 【Chemistry 1】 In the general formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms, and L is a divalent saturated hydrocarbon group which may contain an ether bond, an amide bond, a carbonyl bond, a sulfone bond, or a sulfonamide bond.

2. 2. The active energy ray-curable water-based ink according to claim 1, wherein L is a divalent saturated hydrocarbon group containing at least one bond selected from the group consisting of an ether bond, an amide bond, a carbonyl bond, a sulfone bond, and a sulfonamide bond, and the number of repeating units containing the bond is 1 to 5.

3. 3. The actinic energy ray-curable water-based ink according to claim 1, wherein the content of the water-containing solvent is 50 mass % or more based on the total amount of the actinic energy ray-curable water-based ink.

4. 3. The active energy ray-curable water-based ink according to claim 1, further comprising a polymerization initiator that generates an active species that initiates polymerization of the curable substance upon irradiation with active energy rays.

5. The active energy ray-curable water-based ink according to claim 1 or 2, further comprising a coloring material.

6. 2. The active energy ray-curable water-based ink according to claim 1, wherein the curable substance further contains a monomer not represented by general formula (1), and a ratio of the bifunctional polymerizable monomer represented by general formula (1) to a total amount of the curable substance is 20% by mass or more and 80% by mass or less.

7. The active energy ray-curable water-based ink according to claim 6 , wherein the monomer not corresponding to the general formula (1) is a monomer having one or more (meth)acrylamide groups as a functional group.

8. 8. The active energy ray-curable water-based ink according to claim 6, wherein the monomer not corresponding to the general formula (1) is a monofunctional monomer in an amount of 50 mass% or more relative to a total amount of the curable substance, and a ratio of the difunctional polymerizable monomer of the general formula (1) to the total amount of the curable substance is 25 mass% or more and 50 mass% or less.

9. 8. The active energy ray-curable water-based ink according to claim 6, wherein the monomer not corresponding to general formula (1) is a polyfunctional monomer in an amount of 10% by mass or more and 80% by mass or less relative to a total amount of the curable substance, and a ratio of the bifunctional polymerizable monomer of general formula (1) to the total amount of the polyfunctional monomer not corresponding to general formula (1) is 40% by mass or more.

10. A step of applying an active energy ray-curable water-based ink onto a recording medium; a step of irradiating the active energy ray-curable water-based ink applied onto the recording medium with active energy rays; A recording method comprising at least The active energy ray-curable water-based ink contains water and a curable substance and is curable by active energy rays, The recording method according to the present invention, wherein the curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1): 【Chemistry 2】 In the general formula (1), R １ represents a hydrogen atom or a methyl group, and R ２ represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms, and L is a divalent saturated hydrocarbon group which may contain an ether bond, an amide bond, a carbonyl bond, a sulfone bond, or a sulfonamide bond.

11. The recording method according to claim 10 , wherein the step of applying the ink is carried out by an inkjet recording method.

12. an ink applying device that applies an active energy ray-curable water-based ink onto a recording medium; an active energy ray irradiation device that irradiates the active energy ray curable water-based ink applied onto the recording medium with active energy rays; A recording device having at least The active energy ray-curable water-based ink contains water and a curable substance and is curable by active energy rays, The recording apparatus according to claim 1, wherein the curable substance contains a bifunctional polymerizable monomer represented by the following general formula (1): 【Chemistry 3】 In the general formula (1), R １ represents a hydrogen atom or a methyl group, R ２ represents a divalent saturated hydrocarbon group having 1 to 5 carbon atoms, and L is a divalent saturated hydrocarbon group which may contain an ether bond, an amide bond, a carbonyl bond, a sulfone bond, or a sulfonamide bond.

13. 13. The recording apparatus according to claim 12, wherein the ink applying device comprises a recording head that ejects ink by an inkjet recording method.

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