Inkjet recording device and inkjet recording method

Abstract

Provided is an inkjet recording device and an application therefor, said inkjet recording device comprising: an inkjet head having at least one nozzle for discharging ink containing water and particles containing a polymerizable compound A and a polymer P having an acid group onto a base material; a scanning means for scanning the inkjet head in a scanning direction; a conveying means for conveying the base material in a conveyance direction intersecting the scanning direction; a heating means for heating the base material; a blowing means that in scanned in concert with the inkjet head and that blows a gas onto the surface on which the ink has landed; and a light source for irradiating the surface on which the ink has landed on the base material with active energy rays after the ink discharged from the nozzle has landed on the base material.

Description

Inkjet recording apparatus and inkjet recording method

[0001] The present disclosure relates to an inkjet recording apparatus and an inkjet recording method.

[0002]

[0003] Various studies have been conducted on inkjet recording apparatuses and inkjet recording methods. For example, Japanese Patent No. 6584677 discloses an inkjet ink composition containing water and particles containing a chain polymer including a specific structural unit (1), a specific structural unit (2), and a hydrophilic group, and including a polymerizable group. Japanese Patent Application Laid-Open No. 2014-240070 discloses a droplet ejection device having a ejection unit that ejects droplets of a photocurable liquid material from a nozzle onto a workpiece, a spraying unit that blows an airflow onto the droplets that have landed on the workpiece, an irradiation unit that irradiates light onto the droplets that have landed on the workpiece, and a moving unit that moves the ejection unit, the spraying unit, and the irradiation unit relative to the workpiece, wherein when the direction in which the moving unit moves the workpiece and the ejection unit relative to each other when the droplets are ejected from the nozzle is defined as the main scanning direction, the spraying unit is disposed in the main scanning direction relative to the ejection unit, and the irradiation unit is disposed at a position offset from the ejection unit in a direction perpendicular to the main scanning direction so that an ejection region from which droplets are ejected by the ejection unit and an irradiation region irradiated with light by the irradiation unit do not overlap in the main scanning direction.

[0003] However, it has been difficult to achieve all of the image quality (image quality), abrasion resistance, and stretchability in image recordings obtained by ink jet recording methods.

[0004] The present disclosure has been made in consideration of the above circumstances, and an object of the present invention is to provide an inkjet recording apparatus and an inkjet recording method that are capable of recording images that are excellent in image quality, abrasion resistance, and stretchability.

[0005] The present disclosure includes the following aspects: <1> An inkjet recording apparatus comprising: an inkjet head having at least one nozzle for ejecting an ink containing water, and particles containing a polymer P having an acid group and a polymerizable compound A onto a substrate, a scanning means for scanning the inkjet head in a scanning direction, a transport means for transporting the substrate in a transport direction intersecting the scanning direction, a heating means for heating the substrate, an air blowing means that is scanned in conjunction with the inkjet head and blows air toward a surface of the substrate on which the ink has landed, and a light source that irradiates the surface of the substrate on which the ink has landed with active energy rays after the ink ejected from the nozzle has landed on the substrate. <2> The inkjet recording device according to <1>, wherein, when point A is the end closest to the air blowing means of the nozzle closest to the air blowing port of the at least one nozzle, and point B is a position on the substrate 150 mm away from point A toward the air blowing means in a direction parallel to the scanning direction, the air blowing means blows air at a wind speed of 2 m / s or less at point A and 4 m / s or more at point B. <3> The inkjet recording device according to <2>, wherein the air blowing means blows air at a wind speed of 1 m / s or less at point A and 4 m / s or more at point B. <4> The inkjet recording device according to any one of <1> to <3>, wherein the distance along the transport direction between the end of the nozzle on the downstream side in the transport direction and the end of the light source on the upstream side in the transport direction is 40 mm or more. <5> The inkjet recording device according to any one of <1> to <4>, wherein the heating means heats at a temperature of 35°C to 60°C. <6> An inkjet recording method using the inkjet recording apparatus and ink according to any one of <1> to <5>, comprising: a step of heating a substrate; a step of ejecting the ink onto the substrate; a step of blowing air onto the surface of the substrate on which the ink has landed; and a step of irradiating the surface of the substrate on which the ink has landed with active energy rays.<7> The inkjet recording method according to <6>, wherein the ink further contains an organic solvent, and the water content in the ink that has landed on the substrate at the time of irradiation with actinic energy rays is 5% by mass or less relative to the water content at the time of landing on the substrate, and the organic solvent content in the ink that has landed on the substrate at the time of irradiation with actinic energy rays is 30% by mass or more relative to the organic solvent content at the time of landing on the substrate.<8> The inkjet recording method according to <7>, wherein the mass ratio of the content of the polymerizable compound A to the total content of the polymer P having an acid group and the polymerizable compound A is 0.3 to 0.7.

[0006] According to the present disclosure, there are provided an inkjet recording apparatus and an inkjet recording method capable of recording images with excellent image quality, abrasion resistance, and stretchability.

[0007] FIG. 1 is an external perspective view of an inkjet recording apparatus according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view illustrating a substrate transport path of the inkjet recording apparatus illustrated in FIG. 1. FIG. 3 is a planar perspective view illustrating an example of an arrangement of an inkjet head, a blower, and a light source. FIG. 4A is a planar perspective view illustrating an example of a nozzle arrangement of an inkjet head. FIG. 4B is a planar perspective view illustrating another example of a nozzle arrangement of an inkjet head. FIG. 5A is a cross-sectional perspective view illustrating an example of a blower. FIG. 5B is a cross-sectional perspective view illustrating another example of a blower. FIG. 5C is a cross-sectional perspective view illustrating another example of a blower. FIG. 6 is a schematic perspective view illustrating an example in which a rectifying plate 38A is provided below a blower 33A. FIG. 7 is a diagram illustrating the relationship between points A and B. FIG. 8 is a schematic plan view illustrating an example of the configuration of a light source. FIG. 9 is a block diagram illustrating the configuration of the main parts of a control system of the inkjet recording apparatus. FIG. 10 is a diagram illustrating a character image used to evaluate image definition in the examples.

[0008] In this disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In this disclosure, when a composition contains multiple substances corresponding to each component, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. In numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages, or may be replaced with a value shown in the examples. In this disclosure, the term "step" includes not only independent steps, but also steps that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved. In this disclosure, "*" in a chemical formula represents a bond position.

[0009] In this disclosure, the concept of "image" encompasses not only pattern images (e.g., letters, symbols, or graphics) but also solid images. In this disclosure, "light" encompasses active energy rays such as gamma rays, beta rays, electron beams, ultraviolet rays, and visible light. In this disclosure, ultraviolet rays are sometimes referred to as "UV (Ultra Violet) light." In this disclosure, light generated from an LED (Light Emitting Diode) light source is sometimes referred to as "LED light." In this disclosure, "(meth)acrylic acid" encompasses both acrylic acid and methacrylic acid, "(meth)acrylate" encompasses both acrylate and methacrylate, and "(meth)acryloyl group" encompasses both acryloyl and methacryloyl groups. The elements in the drawings shown in this disclosure are not necessarily drawn to scale; emphasis is placed on clearly illustrating the principles of this disclosure, and some parts are emphasized. Furthermore, components indicated by the same reference numerals in the drawings are identical components.

[0010] [Inkjet Recording Apparatus] The inkjet recording apparatus of the present disclosure includes an inkjet head having at least one nozzle for ejecting an ink containing water and particles containing a polymer P having an acid group and a polymerizable compound A onto a substrate, a scanning means for scanning the inkjet head in a scanning direction, a transport means for transporting the substrate in a transport direction intersecting the scanning direction, a heating means for heating the substrate, an air blowing means that is scanned in conjunction with the inkjet head and blows air toward the surface of the substrate on which the ink has landed, and a light source that irradiates the surface of the substrate on which the ink has landed with active energy rays after the ink ejected from the nozzle has landed on the substrate.

[0011] By using the inkjet recording apparatus of the present disclosure, it is possible to record images that are excellent in image quality, abrasion resistance, and stretchability. The reason for this effect is presumed to be as follows.

[0012] In an image recording mode in which an inkjet ink containing water and particles containing a polymer and a polymerizable compound is deposited on a substrate and the deposited ink is cured by irradiation with active energy rays to obtain an image, it has been difficult to achieve good image quality, abrasion resistance, and stretchability all at the same time.

[0013] The inkjet recording apparatus of the present disclosure includes a heating unit for heating the substrate, an air blowing unit that is scanned in conjunction with the inkjet head and blows air toward the surface of the substrate on which the ink has landed, and a light source that, after the ink ejected from the nozzles has landed on the substrate, irradiates the surface of the substrate on which the ink has landed with active energy rays using the air blowing unit. Therefore, the ink is dried by the heating unit, further dried by the air blowing unit, and cured by the light source. In particular, by drying the ink using the air blowing unit that is scanned in conjunction with the scanning unit, the ink is dried more rapidly than before before being irradiated with active energy rays. The drying evaporates water contained in the ink, and the polymerizable compound A is efficiently exuded from the particles contained in the ink, accelerating the polymerization of the polymerizable compound A, resulting in excellent abrasion resistance and stretchability. Furthermore, because the ink is dried more rapidly than before before being irradiated with active energy rays, interference between ink droplets on the substrate is suppressed, resulting in excellent image quality.

[0014] On the other hand, Japanese Patent No. 6584677 only discloses particles containing a polymerizable monomer, and does not describe a specific configuration of an inkjet recording apparatus. JP-A-2014-240070 does not disclose particles containing a polymerizable compound, and the technical concept is different from that of the present disclosure.

[0015] An example of an inkjet recording apparatus according to the present disclosure will be described below with reference to the drawings.

[0016] 1 is a perspective view of the appearance of an inkjet recording apparatus 10 according to an embodiment of the present disclosure. The inkjet recording apparatus 10 is an apparatus used to apply ink onto a substrate by an inkjet recording method.

[0017] The inkjet recording apparatus 10 includes an apparatus main body 20 and support legs 22 that support the apparatus main body 20. The apparatus main body 20 is provided with platens 26A (not shown), 26B, and 26C, a carriage 30 on which a head unit 24, blowers 33A and 33B, and a light source 34 are mounted, and a guide mechanism 28 as a means (scanning means) for moving the carriage 30. The head unit 24 has inkjet heads 241 and 242, which will be described later.

[0018] In this disclosure, the direction in which the carriage 30 reciprocates (Y direction) is referred to as the "scanning direction." In this disclosure, the direction in which the substrate 12 is transported (X direction) is referred to as the "transport direction." The scanning direction and the transport direction intersect, and are preferably perpendicular to each other.

[0019] The guide mechanism 28 is disposed to extend along the scanning direction (Y direction) of the carriage 30. The carriage 30 is supported so as to be able to move back and forth along the guide mechanism 28 in the scanning direction (Y direction).

[0020] The head unit 24, blowers 33A and 33B, and light source 34, which are arranged on the carriage 30, move integrally (together) with the carriage 30 along the guide mechanism 28. That is, the scanning speed of the carriage 30 is the same as the scanning speed of the head unit 24. Furthermore, the scanning distance per scan of the carriage 30 (the distance traveled in one direction along the scanning direction) is the same as the scanning distance of the head unit 24.

[0021] The scanning speed of the carriage 30 is not particularly limited, but is preferably set to 500 mm / sec to 2000 mm / sec from the viewpoint of further improving the image quality, abrasion resistance, and stretchability of the resulting image.

[0022] The scanning distance of the carriage 30 per scan is not particularly limited, but is preferably 100 mm to 6000 mm, more preferably 500 mm to 6000 mm, and even more preferably 1200 mm to 6000 mm.

[0023] In Figure 1, an attachment portion 38 for ink cartridges 36 is provided on the front left side of the device main body 20 as viewed from the front. The ink cartridges 36 are replaceable ink supply sources (ink tanks) that store ink. The ink cartridges 36 are provided corresponding to the inks used in the inkjet recording device 100. Each ink cartridge 36 for each color is connected to the inkjet head 24 by an ink supply path (not shown) that is formed independently of the other ink cartridges 36.

[0024] FIG. 2 is a schematic cross-sectional view showing a substrate transport path of the inkjet recording apparatus shown in FIG.

[0025] As shown in FIG. 2, the inkjet recording apparatus 10 is provided with platens 26A, 26B, and 26C, which are heating means for heating the substrate 12, and a temperature adjusting unit 50 for adjusting the temperatures of the platens 26A, 26B, and 26C.

[0026] Platen 26A is disposed in an area upstream of head unit 24. By disposing platen 26A, it is possible to heat substrate 12 before image recording. Platen 26B is disposed in an area that includes the area directly below head unit 24. By disposing platen 26B, it is possible to heat substrate 12 during image recording. Platen 26C is disposed in an area downstream of head unit 24. By disposing platen 26C, it is possible to heat substrate 12 after image recording.

[0027] In the inkjet recording apparatus of the present disclosure, the substrate 12 may be heated by at least one of the platens 26A, 26B, and 26C.

[0028] In the inkjet recording apparatus of the present disclosure, it is preferable that at least one of the platens 26A, 26B, and 26C is set to a temperature of 35° C. to 60° C. In particular, from the viewpoint of improving the image quality, abrasion resistance, and stretchability of the obtained image, it is preferable that the platen 26B is set to a temperature of 35° C. to 60° C., and it is more preferable that the platens 26A and 26B are set to a temperature of 35° C. to 60° C.

[0029] In the inkjet recording apparatus of the present disclosure, the heating means may be any means capable of heating the substrate, such as a means for heating at least one surface of the substrate. The heating means may be a means for heating the surface of the substrate opposite to the surface on which the ink lands, a means for heating the surface on which the ink lands, or a means for heating both surfaces of the substrate. Examples of means for heating the surface of the substrate opposite to the surface on which the ink lands include the platen described above. Examples of means for heating the surface of the substrate on which the ink lands include a hot air heater. From the viewpoint of causing the polymerizable compound A to leach out of the particles contained in the ink, it is preferable that the heating means heat the surface of the substrate opposite to the surface on which the ink lands.

[0030] The temperature adjustment unit 50 can adjust the temperatures of the platens 26A, 26B, and 26C individually.

[0031] A pair of nip rollers 40, which are conveying means for intermittently conveying the substrate 12, are disposed between the platens 26A and 26B. The nip rollers 40 move the substrate 12 in the conveying direction (X direction) on the platens 26A, 26B, and 26C.

[0032] A guide 46 for the substrate 12 is provided in the area downstream of the head unit 24. The guide 46 is a means for suppressing deviation in the transport direction.

[0033] A supply roll 42, around which the substrate to be supplied in the transport direction is wound, is provided on the rear side of the inkjet recording apparatus 10. The supply roll 42 is rotatably supported by a frame member (not shown). A take-up roll 44, which takes up the substrate 12 after image recording, is provided on the front side of the inkjet recording apparatus 10. The take-up roll 44 is rotatably supported by a frame member (not shown).

[0034] The head unit 24, the fans 33A and 33B, and the light source 34 will be described in detail below.

[0035] FIG. 3 is a plan view perspective view showing an example of the arrangement of the inkjet heads 241 and 242, the air blowers 33A and 33B, and the light source 34. As shown in FIG.

[0036] (Head Unit) The head unit 24 has inkjet heads 241 and 242. The inkjet heads 241 and 242 are each provided with nozzles for ejecting black ink (K), cyan ink (C), yellow ink (Y), and magenta ink (M). In FIG. 3 , the nozzle rows are indicated by straight lines, and individual nozzles are not shown. In FIG. 3 , the inkjet head 241 is provided with nozzle rows 61Ka, 61Ca, 61Ya, and 61Ma for ejecting the four color inks, and the inkjet head 242 is provided with nozzle rows 61Kb, 61Cb, 61Yb, and 61Mb for ejecting the four color inks. Hereinafter, the nozzle rows 61Ka, 61Kb, 61Ca, 61Cb, 61Ya, 61Yb, 61Ma, and 61Mb will be collectively referred to as nozzle row 61.

[0037] In the present disclosure, the type of ink is not particularly limited. The inkjet heads 241 and 242 may be provided with nozzle rows corresponding to other inks, such as light cyan ink, light magenta ink, white ink, clear ink, and metal ink, in addition to the four colors of ink described above. In FIG. 3 , the nozzle rows corresponding to black ink (K), cyan ink (C), yellow ink (Y), and magenta ink (M) are arranged in this order, but the arrangement order of the nozzle rows for each color is not particularly limited. In FIG. 3 , the head unit 24 has two inkjet heads 241 and 242, but the number of inkjet heads included in the head unit 24 is not particularly limited. In FIG. 3 , the nozzle row of the inkjet head 241 and the nozzle row of the inkjet head 242 partially overlap in the transport direction (X direction). When the head unit 24 has two or more inkjet heads, the relative positions of the inkjet heads are not particularly limited.

[0038] As described above, although the nozzle rows 61 are shown as straight lines in FIG. 3, in reality, each nozzle row 61 is made up of a plurality of nozzles lined up at regular intervals along the transport direction (X direction).

[0039] 4A and 4B are planar perspective views showing the nozzle arrangement of the inkjet heads 241 and 242. As shown in Fig. 4A, the plurality of nozzles 70 may be arranged in a single row. Alternatively, as shown in Fig. 4B, the plurality of nozzles 70 may be arranged in two rows, with the nozzles 70 being alternately staggered.

[0040] 1, the inkjet recording apparatus 10 is provided with fans 33A and 33B, which are air blowing units that blow air onto the surface on which the ink has landed. The fans 33A and 33B blow air onto the surface of the substrate on which the ink has landed, thereby drying the ink.

[0041] As described above, the blowers 33A and 33B are mounted on the carriage 30 together with the head unit 24, and are scanned by the guide mechanism 28, which serves as a means (scanning means) for moving the carriage 30. In other words, the blowers 33A and 33B are scanned in conjunction with the inkjet heads 241 and 242 of the head unit 24.

[0042] The blowers 33A and 33B only need to be scanned in conjunction with the head unit 24 (specifically, the inkjet heads 241 and 242), and do not have to be mounted on the carriage 30 together with the head unit 24. For example, the blowers 33A and 33B may be provided separately from the carriage 30, and may be scanned by a separate guide mechanism that scans in accordance with the scanning direction and scanning speed of the guide mechanism 28.

[0043] The type of gas blown by the fans 33A and 33B is not particularly limited, and may be air taken in from the outside. The temperature of the gas blown is, for example, 20°C to 60°C.

[0044] 5A, 5B, and 5C are schematic cross-sectional views showing an example of the blower 33A.

[0045] 5A to 5C, blower 33A has blower body 331 and blower nozzle 332 attached to the tip of blower body 331. The blower nozzle 332 has an air outlet formed in a lattice pattern. Gas is blown out from a plurality of ventilation holes formed by the lattice.

[0046] The longer the length of the blower nozzle 332 in the direction in which the gas is blown out, the more controllable the flow of the blown gas can be. The length is, for example, 5 mm or more, preferably 10 mm or more, and more preferably 20 mm or more. The upper limit of the length is, for example, 50 mm.

[0047] Furthermore, it is preferable that the air blowing direction of the air blowers 33A and 33B is opposite to the side where the head unit 24 is arranged so that the openings of the nozzle rows 61 do not dry out.

[0048] Specifically, the air blowing direction of the air blowers 33A and 33B is preferably inclined at an angle of 20° or more with respect to the normal direction of the substrate. From the viewpoint of ink drying efficiency, the air blowing direction is preferably inclined at an angle of 50° or less with respect to the normal direction of the substrate.

[0049] For example, the direction of airflow can be adjusted by the arrangement of a grid within the airflow nozzle 332 .

[0050] FIG. 5A shows an example of a blower in which the length of the blower nozzle 332 in the direction in which gas is blown out is relatively short, and the inclination angle of the grid in the blower nozzle is 10° relative to the blowing direction of the blower. The blower is tilted 30° relative to the normal direction of the substrate, but the blowing direction is tilted an additional 10°, allowing air to be blown in a direction of 40° or more relative to the normal direction of the substrate. FIG. 5B shows an example of a blower in which the length of the blower nozzle 332 in the direction in which gas is blown out is longer than that shown in FIG. 5A, and the inclination angle of the grid in the blower nozzle is 0° relative to the blowing direction of the blower. A blower tilted 30° relative to the normal direction of the substrate can blow air in a direction of 30° relative to the normal direction of the substrate. FIG. 5C shows an example of a blower in which the length of the blower nozzle 332 in the direction in which gas is blown out is longer than that shown in FIG. 5A.

[0051] It should be noted that blowers 33A and 33B may have only blower body 331 and may not be equipped with blower nozzle 332. If a blower nozzle is equipped, the blower nozzle may have a lattice structure as shown in Figures 5A to 5C inside the nozzle, or may have a plurality of plates arranged in parallel in one direction inside the nozzle.

[0052] 6 shows an example in which a rectifying plate 38A is provided below the blower 33A. By providing the rectifying plate 38A below the blower 33A, drying of the openings of the nozzle row 61 is suppressed.

[0053] In the inkjet recording apparatus of the present disclosure, it is preferable that the air blowers 33A and 33B blow air at a wind speed of 2 m / s or less at point A and at a wind speed of 4 m / s or more at point B, which will be described later.

[0054] By controlling the wind speed at point A to 2 m / s, the ink landing accuracy is improved, image distortion, crushing, and bleeding are suppressed, and image quality is excellent. Furthermore, by controlling the wind speed at point B to 4 m / s or more, the ink that has landed on the substrate is easily dried, and the polymerizable compound A is efficiently exuded from the particles contained in the ink, accelerating polymerization of the polymerizable compound A, resulting in excellent abrasion resistance and stretchability.

[0055] Point A refers to the end of the nozzle closest to the air outlets of the air blowers 33A and 33B, among at least one nozzle. If it is difficult to measure the air speed at the nozzle due to the structure of the inkjet device, the air speed may be measured near the nozzle closest to the air blowers 33A and 33B, and at a position close to the air blowers 33A and 33B.

[0056] Point B is a position on the substrate 150 mm away from point A in the direction parallel to the scanning direction toward the air blowers 33A and 33B.

[0057] From the above viewpoint, the wind speed at point A is more preferably 1 m / s or less. The wind speed at point A may be 0 m / s. The upper limit of the wind speed at point B is, for example, 15 m / s.

[0058] In the present disclosure, wind speed is measured using an anemometer, such as a wind speed and volume meter manufactured by Custom (product name "WS-06").

[0059] Specifically, in Fig. 3, of the nozzle rows 61, the nozzle row closest to the air outlet of the blower 33A is nozzle row 61Ma, and the nozzle row closest to the air outlet of the blower 33B is nozzle row 61Kb. In Fig. 3, the distance between the air outlet of the blower 33A and the nozzle row 61Ma is compared with the distance between the air outlet of the blower 33B and the nozzle row 61Kb, and the position where the shorter nozzle row (specifically, the nozzles) is located is designated as point A. If the distances are the same, the position where either nozzle row is located is designated as point A. In Fig. 3, the end of the nozzle row 61Ma on the blower 33A side is designated as point APa.

[0060] Fig. 7 is a diagram showing the relationship between point A and point B. As shown in Fig. 7, point B Pb is a position on the substrate 12 that is 150 mm away from point A Pa in a direction parallel to the scanning direction (Y direction) toward the blower 33A.

[0061] It should be noted that the inkjet recording apparatus 10 may be provided with air blowers other than the air blowers 33A and 33B. For example, the air blowers may be provided above the carriage 30, or may be provided upstream of the carriage 30 in the transport direction.

[0062] As other types of blowers, an axial flow fan or a cross flow fan is preferably used. Air is preferably blown in a curtain-like manner across the width of the substrate in the inkjet recording device. Therefore, in the axial flow fan type, it is preferable to arrange multiple fans horizontally. Furthermore, in the cross flow fan type, it is preferable to arrange a fan long enough to blow air across the entire width of the substrate. It is preferable to blow air continuously during ink ejection to form a laminar flow on the surface of the substrate.

[0063] (Light Source) The light source 34 emits active energy rays.

[0064] Examples of light sources include discharge lamps such as mercury lamps, metal halide lamps, high-pressure mercury lamps, medium-pressure mercury lamps, low-pressure mercury lamps, and ultraviolet fluorescent lamps; laser light sources such as gas lasers and solid-state lasers; and semiconductor light sources such as LEDs (light-emitting diodes) and LDs (laser diodes).

[0065] Among these, the light source is preferably a light source for ultraviolet irradiation, such as a metal halide lamp, a high-pressure mercury lamp, a medium-pressure mercury lamp, a low-pressure mercury lamp, or an ultraviolet LED (hereinafter also referred to as UV-LED).

[0066] The peak wavelength of the ultraviolet light is, for example, preferably 200 nm to 405 nm, more preferably 220 nm to 400 nm, and even more preferably 340 nm to 400 nm.

[0067] The peak wavelength of the light from the LED light source (LED light) is preferably 200 nm to 600 nm, more preferably 300 nm to 450 nm, even more preferably 320 nm to 420 nm, even more preferably 340 nm to 405 nm, and even more preferably 355 nm, 365 nm, 385 nm, 395 nm, or 405 nm.

[0068] Examples of UV-LEDs include UV-LEDs manufactured by Nichia Corporation, whose main emission spectrum has a wavelength between 365 nm and 420 nm. Also included are UV-LEDs capable of emitting actinic radiation centered between 300 nm and 370 nm, as described in U.S. Patent No. 6,084,250. Furthermore, by combining several UV-LEDs, it is possible to irradiate ultraviolet rays in different wavelength ranges.

[0069] The light source 34 preferably has a configuration in which a plurality of light source elements are arranged at regular intervals along the scanning direction (Y direction). Examples of the light source elements include UV-LED elements.

[0070] Fig. 8 is a plan view showing an example of the configuration of the light source 34. In Fig. 8, the light source 34 includes 12 light source elements 35. Six light source elements 35 are arranged at equal intervals along the scanning direction and are arranged in two rows with the light source elements 35 shifted alternately.

[0071] The illuminance of the light source 34 is, for example, 500 mW to 15,000 mW.

[0072] As shown in Figures 3, 4A, and 4B, in the inkjet recording device 10 of the present disclosure, it is preferable that the distance along the transport direction between the end of the nozzle 70 on the downstream side in the transport direction and the end of the light source on the upstream side in the transport direction (hereinafter referred to as "distance X1") is 40 mm or more.

[0073] Specifically, the distance X1 means the distance along the transport direction (X direction) between the dashed line D1 and the dashed line D2 in FIG.

[0074] 4A and 4B, dashed line D1 is a straight line parallel to the scanning direction that passes through the center of the nozzle located most downstream in the transport direction among the nozzles included in the nozzle row 61. Dashed line D2 is a straight line parallel to the scanning direction that passes through the center of the light source element located most upstream in the transport direction among the light source elements included in the light source 34, as shown in FIG. 8. Note that "downstream side" means the side facing the transport direction. "Upstream side" means the side facing the opposite direction to the transport direction.

[0075] When the distance X1 is 40 mm or more, the image quality, abrasion resistance, and stretchability of the resulting image are excellent. This is thought to be because the volatile components contained in the ink that has landed on the substrate evaporate, suppressing interference between ink droplets that land on the substrate, and the polymerizable compound A sufficiently seeps out of the particles contained in the ink, accelerating polymerization of the polymerizable compound A. From the viewpoint of further improving the image quality, abrasion resistance, and stretchability of the resulting image, the distance X1 is preferably 40 mm to 150 mm, and more preferably 60 mm to 100 mm.

[0076] The position of the light source relative to the inkjet head is not particularly limited as long as the distance X1 is 40 mm or more. As with the light source 34 shown in Fig. 3, one light source may be disposed at a position away from the head unit 24 in the transport direction. The number of light sources may be two, and in the case of two light sources, the light sources may be disposed at both ends of the head unit 24 in the scanning direction.

[0077] Fig. 9 is a block diagram showing the main configuration of a control system of the inkjet recording apparatus 10. As shown in Fig. 9, the inkjet recording apparatus 10 is provided with a control device 102 as a control means.

[0078] The control device 102 may be, for example, a computer equipped with a central processing unit (CPU). The control device 102 functions as a control device that controls the entire inkjet recording apparatus 10 in accordance with a predetermined program, and also functions as a calculation device that performs various calculations. The control device 102 includes a substrate transport control unit 104, a carriage drive control unit 106, a blower control unit 108, a light source control unit 109, an image processing unit 110, and a discharge control unit 112. Each of these units is realized by a hardware circuit, software, or a combination of these.

[0079] The substrate transport control unit 104 controls a transport drive unit 114 for transporting the substrate 12. The transport drive unit 114 includes a drive motor for driving the nip roller 40 shown in FIG. 2 and a drive circuit for the motor. The substrate 12 transported onto the platens 26A, 26B, and 26C is intermittently fed in the transport direction in accordance with the reciprocating movement in the scanning direction by the head unit 24.

[0080] The carriage drive control unit 106 controls a scan drive unit 116 for moving the carriage 30 in the scanning direction. The scan drive unit 116 includes a drive motor connected to the movement mechanism of the carriage 30 and its control circuit.

[0081] The blower control unit 108 is a means for controlling the operation of the blowers 33A and 33B via a blower drive circuit 118.

[0082] The light source control unit 109 is a control unit that controls the light emission of the light source elements of the light source 34 via the element drive circuit 119 .

[0083] An input device 120 such as an operation panel and a display device 122 are connected to the control device 102. The input device 120 is a means for manually inputting external operation signals to the control device 102, and may take various forms, such as a keyboard, a mouse, a touch panel, or an operation button. The display device 122 may take various forms, such as a liquid crystal display, an organic EL display, or a CRT. By operating the input device 120, the operator can select a drawing mode, input printing conditions, and input / edit auxiliary information, and can confirm various information such as the input contents and search results through the display on the display device 122.

[0084] The inkjet recording apparatus 10 is also provided with an information storage unit 124 for storing various types of information, and an image input interface 126 for importing image data for printing. The image input interface may be a serial interface or a parallel interface. This interface may be equipped with a buffer memory (not shown) for increasing communication speed.

[0085] Image data input via the image input interface 126 is converted into printing data (dot data) by the image processing unit 110. Dot data is generally generated by performing color conversion processing and halftone processing on multi-tone image data. The color conversion processing is a process of converting image data expressed in sRGB or the like (e.g., 8-bit image data for each RGB color) into color data for each ink color used in the inkjet recording apparatus 10.

[0086] The ejection control unit 112 generates an ejection control signal for the head drive circuit 128 based on the dot data generated by the image processing unit 110. The ejection control unit 112 also includes a drive waveform generation unit (not shown). The drive waveform generation unit is means for generating a voltage waveform of a drive voltage for driving ejection energy generating elements (piezo elements in this example) corresponding to each nozzle of the inkjet head 24.

[0087] The drive waveform data is stored in advance in the information storage unit 124, and the drive waveform data to be used is output as needed. The drive waveform output from the drive waveform generation unit is supplied to a head drive circuit 128. The signal output from the drive waveform generation unit may be digital waveform data or an analog voltage signal.

[0088] A common drive voltage is applied to each ejection energy generating element of the inkjet head 24 via the head drive circuit 128, and ink is ejected from the corresponding nozzle by switching on and off a switch element (not shown) connected to the individual electrode of each energy generating element according to the ejection timing of each nozzle.

[0089] The information storage unit 124 stores programs executed by the CPU of the control device 102, various data necessary for control, etc. The information storage unit 124 stores resolution setting information according to the drawing mode, the number of passes (number of scan repetitions), feed amount information necessary for controlling the transport feed amount, control information for the light source 34, etc.

[0090] The number of passes is not particularly limited, but is preferably 1 pass to 32 passes, more preferably 4 passes to 24 passes, and even more preferably 8 passes to 20 passes.

[0091] The encoder 130 is attached to the drive motor of the scan drive unit 116 and the drive motor of the transport drive unit 114, and outputs a pulse signal corresponding to the rotation amount and rotation speed of the drive motor, and the pulse signal is sent to the control device 102. Based on the pulse signal output from the encoder 130, the position of the carriage 30 and the position of the substrate 12 are determined.

[0092] The sensor 132 includes sensors provided in various parts of the device. For example, a sensor that detects the width of the substrate 12 attached to the carriage 30 determines the width of the substrate 12 based on a sensor signal obtained from the sensor 132.

[0093] Other examples of the sensor 132 include a temperature sensor that detects the temperature of the ink, a position detection sensor that detects the position of the substrate, a pressure sensor, etc. For example, based on ink temperature information obtained from a temperature sensor that detects the ink temperature, the control device 102 sends a command signal to a heater control unit (not shown), and the heater control unit controls the operation of the heater based on the command signal from the control device 102.

[0094] <Modifications> The inkjet recording device 10 is provided with a light source 34 as a main curing light source for completely curing the ink, but a provisional curing light source may also be provided in addition to the main curing light source. When a provisional curing light source is provided, it is preferable that the provisional curing light source is also mounted on the carriage 30. The provisional curing light source is a means for irradiating actinic energy rays with an exposure amount smaller than that of the main curing light source. When a provisional curing light source is provided, exposure is performed in the order of the provisional curing light source and the main curing light source (light source 34).

[0095] <Substrate> The substrate used in the inkjet recording apparatus of the present disclosure is not particularly limited, and may be either a non-permeable substrate or a permeable substrate, but is preferably a non-permeable substrate.

[0096] Here, the impermeable substrate refers to a substrate having a water absorption rate (unit: mass %, measurement time: 24 hours) of less than 10 according to ASTM test method ASTM D570.

[0097] The water absorption rate of the impermeable substrate is preferably 5% by mass or less.

[0098] Examples of impermeable substrates include paper laminated with plastic (e.g., polyethylene, polypropylene, polystyrene, etc.), polyester cloth, metal plates (e.g., plates of metals such as aluminum, zinc, copper, etc.), plastic films (e.g., films of polyvinyl chloride (PVC) resin, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), polypropylene (PP), polycarbonate (PC), polyvinyl acetal, acrylic resin, etc.), paper laminated or vapor-deposited with the above-mentioned metals, plastic films laminated or vapor-deposited with the above-mentioned metals, leather, wallpaper, etc. Examples of wallpaper include vinyl chloride wallpaper, olefin wallpaper, and nonwoven fabric wallpaper.

[0099] Examples of leather include natural leather (also called "genuine leather"), synthetic leather (for example, PVC (polyvinyl chloride) leather, PU (polyurethane) leather), etc. For more information on leather, see, for example, paragraphs 0163 to 0165 of JP 2009-058750 A.

[0100] For example, when forming an ink film on an impermeable substrate such as leather (e.g., vehicle seats, bags, shoes, wallets, etc.) or plastic film, the ink film to be formed is required to have excellent abrasion resistance and stretchability.

[0101] Furthermore, when forming an ink film on a substrate other than leather or plastic film, the film to be formed may also be required to have excellent abrasion resistance and stretchability.

[0102] The inkjet recording apparatus of the present disclosure can satisfy such requirements, and from this perspective, it is more effective when PVC is used as the substrate.

[0103] The substrate may be subjected to a surface treatment to improve the surface energy, such as, but not limited to, corona treatment, plasma treatment, flame treatment, heat treatment, abrasion treatment, and light irradiation treatment (UV treatment).

[0104] The thickness of the substrate is not particularly limited, but from the viewpoint of flexibility, it is preferably 20 μm to 500 μm.

[0105] <Ink> The ink used in the inkjet recording apparatus of the present disclosure contains water and particles containing a polymer P having an acid group and a polymerizable compound A. As described above, the inkjet recording apparatus of the present disclosure is suitable for recording images using ink containing water and particles containing a polymer P having an acid group and a polymerizable compound A. By using the inkjet recording apparatus of the present disclosure, the polymerizable compound A is sufficiently exuded from the particles contained in the ink, accelerating polymerization of the polymerizable compound A and resulting in excellent abrasion resistance and stretchability.

[0106] Each component contained in the ink will be described in detail below.

[0107] (Water) The ink contains water. The water content relative to the total amount of the ink can be, for example, 10% by mass or more and 99% by mass or less. The water content relative to the total amount of the ink is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 50% by mass or more.

[0108] The upper limit of the water content relative to the total amount of ink is determined appropriately depending on the contents of other components, but is, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0109] <Particles> The ink contains at least one type of particle containing a polymer P and a polymerizable compound A (hereinafter also referred to as "specific particles"). In the ink, the inclusion of the polymer P and the polymerizable compound A in the specific particles contributes to the storage stability of the ink. A preferred embodiment of the ink is one in which the polymerizable compound A remains in the specific particles in the ink before it is applied onto a substrate, and in which the polymerizable compound A seeps out from the specific particles in the ink after it has been applied onto a substrate.

[0110] (Polymerizable Compound A) The specific particles contain at least one type of polymerizable compound A. The specific particles may contain only one type of polymerizable compound A, or two or more types of polymerizable compounds A.

[0111] The polymerizable compound A is not particularly limited as long as it is a compound having a polymerizable group.

[0112] The molecular weight of the polymerizable compound A is not particularly limited, but from the viewpoint of improving the stretchability of the image, the weight average molecular weight is preferably 1,000 or more, more preferably 1,500 or more, and even more preferably 2,000 or more. On the other hand, the upper limit of the weight average molecular weight of the polymerizable compound A is not particularly limited, but from the viewpoint of dispersion stability, it is preferably 20,000 or less, more preferably 15,000 or less. The weight average molecular weight of the polymerizable compound A may be in the range of 1,000 to 20,000.

[0113] In this disclosure, weight average molecular weight (Mw) refers to the value measured by gel permeation chromatography (GPC).

[0114] Measurements by GPC were performed using an HLC (registered trademark)-8020GPC (Tosoh Corporation) as the measuring device, three TSKgel (registered trademark) Super Multipore HZ-H columns (4.6 mm ID x 15 cm, Tosoh Corporation), and THF (tetrahydrofuran) as the eluent. The measurement conditions were a sample concentration of 0.45% by mass, a flow rate of 0.35 ml / min, a sample injection volume of 10 μL, and a measurement temperature of 40 ° C., and the measurement was performed using an RI detector. A calibration curve was prepared from eight samples of "Standard Sample TSK Standard, Polystyrene" from Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene". The type of polymerizable group contained in the polymerizable compound A is not particularly limited, but from the viewpoint of curability, it is more preferably an ethylenically unsaturated group.

[0115] Examples of the ethylenically unsaturated group contained in the polymerizable compound A include a (meth)acryloyl group, a vinyl group, a vinyl ester group, and a vinyl ether group. From the viewpoint of reactivity, the ethylenically unsaturated group is preferably a (meth)acryloyl group or a vinyl group, and more preferably a (meth)acryloyl group. Examples of the (meth)acryloyl group include a (meth)acryloyloxy group and a (meth)acrylamide group. Among these, from the viewpoint of further improving the scratch resistance of the image, the ethylenically unsaturated group is preferably a (meth)acryloyl group, more preferably an acryloyl group, and even more preferably an acryloyloxy group.

[0116] The number of polymerizable groups possessed by the polymerizable compound A may be 1 or 2 or more, but from the viewpoint of improving the scratch resistance of the image, it is preferably 2 or more. The upper limit of the number of polymerizable groups is not particularly limited, and is, for example, 20. From the viewpoint of ease of synthesis, it is preferable that the number of ethylenically unsaturated groups is 2, 3, 6, 9, 10, 15, or 20.

[0117] In addition, from the viewpoint of further improving the scratch resistance of the image, the polymerizable compound A is preferably a urethane (meth)acrylate having two or more (meth)acryloyl groups in one molecule.

[0118] Urethane (meth)acrylate is a compound having a (meth)acryloyl group and a urethane bond. When polymerizable compound A contains a urethane bond, adhesion to the substrate is improved, which is thought to improve the scratch resistance of the image. Furthermore, hydrogen bonding between the urethane bonds is thought to improve the strength of the ink film, resulting in improved scratch resistance of the image.

[0119] The urethane (meth)acrylate can be produced, for example, by reacting a bifunctional isocyanate compound with a hydroxyl group-containing (meth)acrylate and, optionally, with a polyol.

[0120] Examples of bifunctional isocyanate compounds include methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dipropyl ether diisocyanate, 2,2-dimethylpentane diisocyanate, 3-methoxyhexane diisocyanate, octamethylene diisocyanate, 2,2,4-trimethylpentane diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 3-butoxyhexane diisocyanate, 1,4-butylene glycol dipropyl ether diisocyanate, thiodihexane aliphatic diisocyanates such as silyl diisocyanate; aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, dimethylbenzene diisocyanate, ethylbenzene diisocyanate, isopropylbenzene diisocyanate, tolidine diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate, metaxylylene diisocyanate, paraxylylene diisocyanate, and tetramethylxylylene diisocyanate; and alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane 4,4'-diisocyanate.

[0121] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, phenyl glycidyl ether (meth)acrylate, pentaerythritol (meth)triacrylate, and dipentaerythritol penta(meth)acrylate.

[0122] Examples of the polymerizable compound A include acrylate compounds, methacrylate compounds, styrene compounds, vinylnaphthalene compounds, N-vinyl heterocyclic compounds, N-vinylamides, unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.

[0123] Examples of acrylate compounds include 2-hydroxyethyl acrylate, butoxyethyl acrylate, carbitol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, 2-phenylphenoxyethyl acrylate, benzyl acrylate, tridecyl acrylate, 2-phenoxyethyl acrylate (PEA), bis(4-acryloxypolyethoxyphenyl)propane, oligoester acrylate, epoxy acrylate, isobornyl acrylate (IBOA), dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, cyclic trimethylolpropane formal acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-vinyloxyethoxy)ethyl acrylate, octyl acrylate, decyl acrylate, isodecyl acrylate, lauryl acrylate, 3,3,5-trimethyl monofunctional acrylate compounds such as cyclohexyl acrylate, 4-t-butylcyclohexyl acrylate, isoamyl acrylate, stearyl acrylate, isostearyl acrylate, 2-ethylhexyl diglycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hydrophthalic acid, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, vinyl ether acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyphthalic acid, 2-acryloxyethyl-2-hydroxyethyl phthalic acid, lactone-modified acrylate, acryloylmorpholine, acrylamide, and substituted acrylamides (for example, N-methylolacrylamide and diacetone acrylamide);Polyethylene glycol diacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate (HDDA), 1,9-nonanediol diacrylate (NDDA), 1,10-decanediol diacrylate (DDDA), 3-methylpentanediol diacrylate (3MPDDA), neopentyl glycol diacrylate, tricyclodecane dimethanol diacrylate, bisphenol A ethylene oxide (EO) adduct diacrylate, bisphenol A propylene oxide (PO) adduct diacrylate, ethoxylated bisphenol A diacrylate, hydrochloric acid bifunctional acrylate compounds such as xyneopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethyloltricyclodecane diacrylate, polytetramethylene glycol diacrylate, alkoxylated cyclohexanone dimethanol diacrylate, alkoxylated hexanediol diacrylate, dioxane glycol diacrylate, cyclohexanone dimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), and neopentyl glycol propylene oxide adduct diacrylate;Trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, caprolactone Examples of the acrylate compound include tri- or higher functional acrylate compounds such as lactone-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxytetraacrylate, glycerin propoxy triacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerin triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate;

[0124] Examples of the methacrylate compound include monofunctional methacrylate compounds such as methyl methacrylate, n-butyl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylaminomethyl methacrylate, methoxypolyethylene glycol methacrylate, methoxytriethylene glycol methacrylate, hydroxyethyl methacrylate, phenoxyethyl methacrylate, and cyclohexyl methacrylate; and bifunctional methacrylate compounds such as polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2-bis(4-methacryloxypolyethoxyphenyl)propane, and tetraethylene glycol dimethacrylate.

[0125] Examples of styrene compounds include styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene.

[0126] Examples of vinylnaphthalene compounds include 1-vinylnaphthalene, methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4-methyl-1-vinylnaphthalene, and 4-methoxy-1-vinylnaphthalene.

[0127] Examples of N-vinyl heterocyclic compounds include N-vinylcarbazole, N-vinylpyrrolidone, N-vinylethylacetamide, N-vinylpyrrole, N-vinylphenothiazine, N-vinylacetanilide, N-vinylethylacetamide, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazole.

[0128] N-vinylamides include, for example, allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, and N-vinylformamide.

[0129] Among these, the difunctional or less radical polymerizable monomer is preferably at least one selected from 1,6-hexanediol diacrylate (HDDA), 1,9-nonanediol diacrylate (NDDA), 1,10-decanediol diacrylate (DDDA), 3-methylpentadiol diacrylate (3MPDDA), neopentyl glycol diacrylate, tricyclodecane dimethanol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), cyclohexanone dimethanol diacrylate, alkoxylated hexanediol diacrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate.

[0130] The trifunctional or higher radical polymerizable monomer is preferably at least one selected from trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxy tetraacrylate, glycerin propoxy triacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerin triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate.

[0131] Examples of combinations of difunctional or lower radical polymerizable monomers and trifunctional or higher radical polymerizable monomers include a combination of a difunctional acrylate compound and a trifunctional acrylate compound, a combination of a difunctional acrylate compound and a pentafunctional acrylate compound, and a combination of a monofunctional acrylate compound and a tetrafunctional acrylate compound.

[0132] The polymerizable compound A is preferably a polymerizable compound having a cyclic structure, such as tricyclodecane dimethanol di(meth)acrylate, bisphenol A ethylene oxide (EO) adduct di(meth)acrylate, bisphenol A propylene oxide (PO) adduct di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, alkoxylated dimethylol tricyclodecane di(meth)acrylate, alkoxylated cyclohexanone dimethanol di(meth)acrylate, cyclohexanone dimethanol di(meth)acrylate, etc. monofunctional cyclic (meth)acrylates such as cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; ethoxylated isocyanuric acid tri(meth)acrylate, or ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate are more preferred, with the above-mentioned difunctional cyclic (meth)acrylates, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, and dicyclopentanyl acrylate being even more preferred, and the above-mentioned difunctional cyclic (meth)acrylates being particularly preferred.

[0133] In addition to the above, commercially available products described in "Crosslinking Agent Handbook" edited by Yamashita Shinzo (Taiseisha, 1981); "UV-EB Curing Handbook (Raw Materials Edition)" edited by Kato Kiyomi (Kobunshi Kankokai, 1985); "Applications and Markets of UV-EB Curing Technology" edited by RadTech Research Group, p. 79 (CMC, 1989); "Polyester Resin Handbook" by Takiyama Eiichiro (Nikkan Kogyo Shimbun, 1988), and the like, as well as radically polymerizable compounds known in the industry, can be used.

[0134] Further, photocurable polymerizable monomers used in photopolymerizable compositions described in JP-A Nos. 7-159983, 7-31399, 8-224982, 10-863, 9-134011, and JP-T No. 2004-514014 are known, and these can also be used as the polymerizable compound A that can be contained in the specific particles.

[0135] The polymerizable compound A may be a commercially available product. Examples of commercially available products include AH-600 (bifunctional), AT-600 (bifunctional), UA-306H (hexafunctional), UA-306T (hexafunctional), UA-306I (hexafunctional), UF-8001G (bifunctional), DAUA-167 (bifunctional), Light Acrylate NPA (bifunctional), and Light Acrylate 3EG-A (bifunctional) (all manufactured by Kyoeisha). Chemical Co., Ltd.), SR339A (PEA, monofunctional), SR506 (IBOA, monofunctional), CD262 (bifunctional), SR238 (HDDA, bifunctional), SR341 (3MPDDA, bifunctional), SR508 (bifunctional), SR306H (bifunctional), CD560 (bifunctional), SR833S (bifunctional), SR444 (trifunctional), SR454 (trifunctional), SR492 (trifunctional) functional), SR499 (trifunctional), CD501 (trifunctional), SR502 (trifunctional), SR9020 (trifunctional), CD9021 (trifunctional), SR9035 (trifunctional), SR494 (tetrafunctional), SR399E (pentafunctional) (all from Sartomer), A-NOD-N (NDDA, bifunctional), A-DOD-N (DDDA, bifunctional), A-200 (bifunctional), APG-40 0 (bifunctional), A-BPE-10 (bifunctional), A-BPE-20 (bifunctional), A-9300 (trifunctional), A-9300-1CL (trifunctional), A-TMPT (trifunctional), A-TMM-3L (trifunctional), A-TMMT (tetrafunctional), AD-TMP (tetrafunctional) (all manufactured by Shin-Nakamura Chemical Co., Ltd.), UV-7510B (trifunctional) (Nippon Synthetic Chemical Industry Co., Ltd.), KAYARAD DPCA-30 (hexafunctional), and KAYARAD DPEA-12 (hexafunctional) (all manufactured by Nippon Kayaku Co., Ltd.).

[0136] Examples of commercially available products include NPGPODA (neopentyl glycol propylene oxide adduct diacrylate), SR531, SR285, and SR256 (all manufactured by Sartomer Corporation), A-DHP (dipentaerythritol hexaacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.), Aronix (registered trademark) M-156 (manufactured by Toagosei Co., Ltd.), V-CAP (manufactured by BASF), and Viscoat #192 (manufactured by Osaka Organic Chemical Industry Ltd.).

[0137] Among these, SR506, SR833S, A-9300, and A-9300-CL, which are polymerizable monomers having a cyclic structure, are particularly preferred, with SR833S being more preferred.

[0138] The content of the polymerizable compound A in the ink is preferably 1% by mass to 15% by mass, and more preferably 2% by mass to 8% by mass, based on the total amount of the ink.

[0139] (Polymer P Having Acid Group) The specific particles contain at least one type of polymer P having an acid group (hereinafter also simply referred to as "polymer P").

[0140] The polymer P plays a role in keeping the polymerizable compound A within specific particles in the ink before it is applied to the substrate, thereby contributing to improving the storage stability of the ink.

[0141] The polymer P may be a chain polymer or a cross-linked polymer.

[0142] In the present disclosure, a linear polymer refers to a polymer that does not have a cross-linked structure, and a cross-linked polymer refers to a polymer that has a cross-linked structure.

[0143] The chain polymer may have a cyclic structure or a branched structure.

[0144] For specific particles containing polymer P, which is a chain polymer, see, for example, Japanese Patent No. 6584677.

[0145] A preferred embodiment of the specific particle when the polymer P is a crosslinked polymer is a microcapsule comprising a shell made of the polymer P, which is a crosslinked polymer, and a core containing a polymerizable compound.

[0146] For specific particles containing polymer P, which is a crosslinked polymer, see, for example, Japanese Patent No. 6510681.

[0147] —Weight Average Molecular Weight (Mw)— The weight average molecular weight (Mw) of the polymer P is preferably 3,000 to 200,000, more preferably 4,000 to 150,000, even more preferably 5,000 to 100,000, still more preferably 8,000 to 80,000, and still more preferably 10,000 to 50,000.

[0148] The storage stability of the ink is further improved when the Mw of the polymer P is 3000 or more. This is thought to be because, when the Mw of the polymer P is 3000 or more, the function of the polymer P (the function of retaining the polymerizable compound A within the specific particles; in other words, the function of suppressing the exudation of the polymerizable compound A from the specific particles) is more effectively exhibited in the ink before it is applied to the substrate.

[0149] When the Mw of polymer P is 200,000 or less, the blocking resistance of the image is further improved. The reason for this is thought to be that when the Mw of polymer P is 200,000 or less, the decrease in fluidity (i.e., thickening) during the drying process of the ink applied to the substrate is suppressed, and as a result, the volatilization of liquid components (i.e., water and water-soluble organic solvents) from the ink is further promoted.

[0150] —Glass Transition Temperature (Tg)— There are no particular limitations on the glass transition temperature (Tg) of the polymer P. From the viewpoint of improving the mobility of the polymer P and further improving the image quality (specifically, suppressing image graininess), the Tg of the polymer P is preferably 120° C. or lower, more preferably 100° C. or lower, even more preferably 80° C. or lower, and still more preferably 70° C. or lower.

[0151] On the other hand, the Tg of the polymer P is preferably 0° C. or higher, more preferably 10° C. or higher, even more preferably 20° C. or higher, and even more preferably 30° C. or higher.

[0152] In this disclosure, the glass transition temperature (Tg) of a polymer means the value measured using differential scanning calorimetry (DSC).

[0153] The glass transition temperature is specifically measured according to the method described in JIS K 7121 (1987) or JIS K 6240 (2011). The glass transition temperature in this disclosure is the extrapolated glass transition onset temperature (hereinafter, sometimes referred to as "Tig"). The method for measuring the glass transition temperature will be described in more detail below. To determine the glass transition temperature, the apparatus is held at a temperature approximately 50°C lower than the expected glass transition temperature of the resin until the apparatus stabilizes, and then heated at a heating rate of 20°C / min to a temperature approximately 30°C higher than the temperature at which the glass transition ends, to create a differential thermal analysis (DTA) curve or a DSC curve. The extrapolated glass transition onset temperature (Tig), i.e., the glass transition temperature in this disclosure, is determined as the temperature at the intersection of a straight line extending the low-temperature baseline of the DTA curve or DSC curve toward the high-temperature side and a tangent drawn at the point where the gradient of the step-like change in the glass transition curve is maximum. When the ink contains two or more types of polymer P, the glass transition temperature (Tg) of the polymer P means the weighted average of the glass transition temperatures of the individual polymers P.

[0154] Examples of the polymer P include urethane polymer, urethane urea polymer, urea polymer, acrylic polymer, polyester, polyolefin, polystyrene, polycarbonate, and polyamide.

[0155] Here, the term "urethane polymer" refers to a polymer that contains a urethane bond but does not contain a urea bond, the term "urea polymer" refers to a polymer that contains a urea bond but does not contain a urethane bond, and the term "urethane-urea polymer" refers to a polymer that contains a urethane bond and a urea bond.

[0156] Further, the acrylic polymer means a polymer (homopolymer or copolymer) of raw material monomers containing at least one selected from the group consisting of acrylic acid, derivatives of acrylic acid (e.g., acrylic acid esters), methacrylic acid, and derivatives of methacrylic acid (e.g., methacrylic acid esters).

[0157] - Bond U - The polymer P preferably contains at least one of a urethane bond and a urea bond, namely, a bond U. In other words, the polymer P is preferably a urethane polymer, a urethane-urea polymer, or a urea polymer.

[0158] When the polymer P contains a bond U, the specific particles are likely to interact with each other in the ink that has landed on the substrate due to interactions (e.g., hydrogen bonds) between the bonds U. This makes it easier for the specific particles to be linked together by polymerization of the polymerizable compound A that has seeped out of the specific particles. This makes it easier for curing to proceed between the specific particles, further improving the scratch resistance of the image.

[0159] The bond U preferably contains a urethane bond. In other words, the polymer P preferably contains a urethane bond and no urea bond, or contains a urethane bond and a urea bond.

[0160] - Acid Group - The polymer P preferably contains at least one type of acid group, which contributes to the dispersion stability of the specific particles in the ink, and as a result, the storage stability of the ink is further improved.

[0161] The acid groups may be neutralized or unneutralized.

[0162] Examples of the unneutralized acid group include a carboxy group, a sulfo group, a sulfate group, a phosphonic acid group, and a phosphate group.

[0163] A neutralized acid group refers to an acid group in the form of a "salt" (for example, a salt of a carboxy group (e.g., -COONa)). Examples of neutralized acid groups include salts of acid groups such as salts of a carboxy group, salts of a sulfo group, salts of a sulfate group, salts of a phosphonic acid group, and salts of a phosphoric acid group.

[0164] Neutralization can be carried out using, for example, an alkali metal hydroxide (such as sodium hydroxide or potassium hydroxide) or an organic amine (such as triethylamine).

[0165] From the viewpoint of further improving the storage stability of the ink, the acid group in polymer P is preferably at least one selected from the group consisting of a carboxy group, a salt of a carboxy group, a sulfo group, a salt of a sulfo group, a sulfate group, a salt of a sulfate group, a phosphonic acid group, a salt of a phosphonic acid group, a phosphoric acid group, and a salt of a phosphoric acid group, and more preferably at least one selected from the group consisting of a carboxy group, a salt of a carboxy group, a sulfo group, and a salt of a sulfo group.

[0166] The "salt" in the above-mentioned salts of a carboxy group, salts of a sulfo group, salts of a sulfate group, salts of a phosphonic acid group, and salts of a phosphoric acid group is preferably an alkali metal salt or an organic amine salt, more preferably an organic amine salt.

[0167] The organic amine in the organic amine salt is preferably N,N-diisopropylethylamine or triethylamine.

[0168] Furthermore, when the total number of millimoles of acid groups (e.g., carboxy groups and salts of carboxy groups) contained in 1 g of polymer P is defined as the acid value of polymer P, the acid value of polymer P is preferably 0.10 mmol / g to 2.00 mmol / g, and more preferably 0.30 mmol / g to 1.50 mmol / g, from the viewpoint of dispersion stability.

[0169] The degree of neutralization of the acid groups in the polymer P is preferably 50% to 100%, more preferably 70% to 100%.

[0170] Here, the degree of neutralization refers to the ratio of the "number of neutralized acid groups" to the "total number of unneutralized acid groups (e.g., carboxy groups) and the number of neutralized acid groups (e.g., salts of carboxy groups)" in polymer P (i.e., the ratio [number of neutralized acid groups / (number of unneutralized acid groups+number of neutralized acid groups)]). The degree of neutralization of acid groups in polymer P can be measured by neutralization titration.

[0171] —Polymerizable Group— The specific particles contain not only the polymer P but also the polymerizable compound A. Therefore, the polymer P does not necessarily need to contain a polymerizable group. However, from the viewpoint of further improving the scratch resistance of the image, the polymer P may contain a polymerizable group.

[0172] The polymerizable group that can be contained in the polymer P is preferably a photopolymerizable group or a thermally polymerizable group.

[0173] The photopolymerizable group is preferably a radically polymerizable group, more preferably a group containing an ethylenic double bond, and even more preferably a (meth)acryloyl group, an allyl group, a styryl group, or a vinyl group. As the radically polymerizable group, a (meth)acryloyl group is particularly preferred from the viewpoints of radical polymerization reactivity and the hardness of the film formed.

[0174] The thermally polymerizable group is preferably an epoxy group, an oxetanyl group, an aziridinyl group, an azetidinyl group, a ketone group, an aldehyde group, or a blocked isocyanate group.

[0175] The polymer P may contain only one type of polymerizable group, or may contain two or more types of polymerizable groups.

[0176] The presence of polymerizable groups in the polymer P can be confirmed, for example, by Fourier transform infrared spectroscopy (FT-IR) analysis.

[0177] When the number of millimoles of ethylenic double bonds in 1 g of polymer P is defined as the C=C value of polymer P, from the viewpoint of further improving the hardness of the image, the C=C value of polymer P is preferably 0.05 mmol or more, more preferably 0.10 mmol / g or more, even more preferably 0.30 mmol / g or more, and particularly preferably 0.50 mmol / g or more.

[0178] From the viewpoint of further improving the water resistance and alcohol resistance of the image, the C═C value of the polymer P is preferably 0.05 mmol or more, more preferably 0.10 mmol / g or more, even more preferably 0.30 mmol / g or more, still more preferably 0.50 mmol / g or more, still more preferably 0.60 mmol / g or more, and particularly preferably 0.70 mmol / g or more.

[0179] On the other hand, from the viewpoint of improving the curability of the ink over time (i.e., suppressing deterioration in the curability of the ink over time), the C═C value of polymer P is preferably 4.00 mmol / g or less, more preferably 3.00 mmol / g or less, even more preferably 2.00 mmol / g or less, and particularly preferably 1.50 mmol / g or less.

[0180] The polymer P may contain a structure other than the above-described structures (i.e., the bond U, the hydrophilic group, and the polymerizable group). Examples of the other structure include a polysiloxane bond (i.e., a divalent polysiloxane group), a monovalent polysiloxane group, a monovalent fluorohydrocarbon group, and a divalent fluorohydrocarbon group.

[0181] —Preferred Structure of Polymer P— The polymer P preferably contains a structural unit derived from an isocyanate compound and a structural unit derived from a compound containing an active hydrogen group.

[0182] The polymer P in the above preferred embodiment contains a bond U formed by the reaction of an isocyanate group of an isocyanate compound with an active hydrogen group of a compound containing an active hydrogen group.

[0183] The active hydrogen group is preferably a hydroxy group, a primary amino group, or a secondary amino group. For example, a urethane group is formed by the reaction of an isocyanate group with a hydroxy group. Also, a urea group is formed by the reaction of an isocyanate group with a primary amino group or a secondary amino group.

[0184] The isocyanate compound and the compound containing an active hydrogen group, which are raw materials for the polymer P having the above-described preferred structure, may be referred to as raw material compounds hereinafter.

[0185] The raw material compound may be a single isocyanate compound or two or more compounds. The raw material compound may be a single active hydrogen group-containing compound or two or more compounds.

[0186] At least one of the isocyanate compounds used as raw material compounds is preferably a di- or higher functional isocyanate compound.

[0187] As at least one of the compounds containing an active hydrogen group as the raw material compound, a compound containing two or more active hydrogen groups is preferred.

[0188] Among the raw material compounds, at least one of the isocyanate compound and the compound containing an active hydrogen group preferably contains a hydrophilic group. This makes it easy to produce a polymer P containing a hydrophilic group. In this case, at least some of the hydrophilic groups in the finally obtained polymer P may be groups obtained by neutralizing the hydrophilic groups in the raw material compounds. A more preferred embodiment is one in which at least one of the compounds containing an active hydrogen group among the raw material compounds is a compound containing an active hydrogen group and a hydrophilic group.

[0189] When the polymer P contains a polymerizable group, it is preferable that at least one of the isocyanate compound and the compound containing an active hydrogen group among the raw material compounds contains a polymerizable group. This makes it easy to produce the polymer P containing a polymerizable group. A more preferred embodiment is one in which at least one of the compounds containing an active hydrogen group among the raw material compounds is a compound containing an active hydrogen group and a polymerizable group.

[0190] As described above, the polymer P may be a linear polymer or a crosslinked polymer. The linear polymer as the polymer P can be produced by reacting a bifunctional isocyanate compound with a compound containing two active hydrogen groups. The crosslinked polymer as the polymer P can be produced by reacting a trifunctional or higher isocyanate compound with a compound containing two or more active hydrogen groups. The crosslinked polymer as the polymer P can also be produced by reacting a bifunctional isocyanate compound with a compound containing three or more active hydrogen groups.

[0191] Preferred raw material compounds will be described below.

[0192] -Isocyanate Compound- The isocyanate compound is preferably a di- or higher functional isocyanate compound, more preferably a di- to hexa-functional isocyanate compound.

[0193] When a bifunctional isocyanate compound is used as the raw material compound, the polymer P contains the following structural unit (P1), which is a structural unit derived from the bifunctional isocyanate compound.

[0194]

[0195] In the structural unit (P1), L １ represents a divalent organic group having 1 to 20 carbon atoms, and * represents the bonding position.

[0196] L １ Specific examples of the above include residues obtained by removing two isocyanate groups (NCO groups) from the bifunctional isocyanate compounds according to the following specific examples.

[0197] Specific examples of the bifunctional isocyanate compound are as follows: However, the bifunctional isocyanate compound is not limited to the following specific examples.

[0198]

[0199] In addition, as the bifunctional isocyanate compound, bifunctional isocyanate compounds derived from the above specific examples can also be used, such as Duranate (registered trademark) D101, D201, and A101 (manufactured by Asahi Kasei Corporation).

[0200] The tri- or higher functional isocyanate compound is preferably a reaction product of at least one selected from the group consisting of bifunctional isocyanate compounds and at least one selected from the group consisting of compounds containing three or more active hydrogen groups (e.g., tri- or higher functional polyol compounds, tri- or higher functional polyamine compounds, and tri- or higher functional polythiol compounds). The number of moles (number of molecules) of the bifunctional isocyanate compound to be reacted with the compound containing three or more active hydrogen groups is preferably 0.6 times or more, more preferably 0.6 to 5 times, even more preferably 0.6 to 3 times, and even more preferably 0.8 to 2 times the number of moles of active hydrogen groups (number of equivalents of active hydrogen groups) in the compound containing three or more active hydrogen groups.

[0201] Examples of the bifunctional isocyanate compound for forming a trifunctional or higher isocyanate compound include the bifunctional isocyanate compounds according to the specific examples described above.

[0202] Examples of compounds containing three or more active hydrogen groups for forming trifunctional or higher isocyanate compounds include the compounds described in paragraphs 0057 to 0058 of WO 2016 / 052053.

[0203] Examples of tri- or higher functional isocyanate compounds include adduct-type tri- or higher functional isocyanate compounds, isocyanurate-type tri- or higher functional isocyanate compounds, biuret-type tri- or higher functional isocyanate compounds, etc. Commercially available adduct-type tri- or higher functional isocyanate compounds include Takenate (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (all Mitsui Chemicals, Inc.), Desmodur (registered trademark) L75, UL57SP (Sumika Bayer Urethane Co., Ltd.), Coronate (registered trademark) HL, HX, L (Nippon Urethane Polymer Co., Ltd.), P301-75E (Asahi Kasei Corporation), and the like. Commercially available isocyanurate-type trifunctional or higher isocyanate compounds include Takenate (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N (all Mitsui Chemicals, Inc.), Sumidur N3300, Desmodur (registered trademark) N3600, N3900, Z4470BA (all Sumika Bayer Urethane Co., Ltd.), Coronate (registered trademark) HX, HK (all Nippon Urethane Polymer Co., Ltd.), Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (all Asahi Kasei Corporation), and the like. Commercially available biuret-type tri- or higher functional isocyanate compounds include Takenate (registered trademark) D-165N and NP1100 (both manufactured by Mitsui Chemicals, Inc.), Desmodur (registered trademark) N3200 (manufactured by Sumika Bayer Urethane Co., Ltd.), and Duranate (registered trademark) 24A-100 (manufactured by Asahi Kasei Corporation).

[0204] At least one of the isocyanate compounds used as raw material compounds may be an isocyanate compound containing a hydrophilic group. For details about isocyanate compounds containing a hydrophilic group, see paragraphs

[0112] to

[0118] and

[0252] to

[0254] of WO 2016 / 052053. At least one of the isocyanate compounds used as raw material compounds may be an isocyanate compound containing a polymerizable group. For details about isocyanate compounds containing a polymerizable group, see paragraphs

[0084] to

[0089] ,

[0203] , and

[0205] of WO 2016 / 052053.

[0205] - Compound containing an active hydrogen group - The compound containing an active hydrogen group is preferably a compound containing two or more active hydrogen groups. The compound containing two or more active hydrogen groups is more preferably a polyol compound (i.e., a compound having two or more hydroxy groups) or a polyamine compound (i.e., a compound having two or more amino groups).

[0206] When a compound containing an active hydrogen group and a hydrophilic group is used as a raw material compound, the polymer P preferably contains at least one of the following structural units (P0).

[0207]

[0208] In the structural unit (P0), L ０ represents a divalent organic group; １ and Y ２ are each independently an oxygen atom, a sulfur atom, or —NR １ represents a - group, R １ represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and * represents the bonding position.

[0209] In the structural unit (P0), L ０ The divalent organic group represented by the formula (I) may be a group consisting of carbon atoms and hydrogen atoms, or may be a group containing carbon atoms and hydrogen atoms and also containing a heteroatom (for example, an oxygen atom, a nitrogen atom, a sulfur atom, etc.). ０ The divalent organic group represented by the formula (I) may contain at least one of a hydrophilic group and a polymerizable group. ０Specific examples of the compound include residues obtained by removing two active hydrogen groups from the specific examples of compounds containing two or more active hydrogen groups described below.

[0210] R １ is preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms. １ and Y ２ are each independently an oxygen atom or —NR １ It is preferably a - group, and more preferably an oxygen atom.

[0211] Specific examples of diol compounds as compounds containing active hydrogen groups are shown below, but the compounds containing active hydrogen groups are not limited to the following specific examples.

[0212]

[0213] In compounds (12) to (15), nC ７ H １５ , nC ９ H １９ , nC １１ H ２３ , and nC １７ H ３５represent a normal heptyl group, a normal nonyl group, a normal undecyl group, and a normal heptadecyl group, respectively. Compound (16) PPG is polypropylene glycol, and n is the number of repetitions. Compound (16-2) PEG is polyethylene glycol, and n is the number of repetitions. Compound (17) PEs is polyester diol, and n is the number of repetitions, and Ra and two Rb's are each independently a divalent hydrocarbon group having 2 to 25 carbon atoms. The n Ra's in compound (17) PEs may be the same or different. The (n+1) Rb's in compound (17) PEs may be the same or different. Compound (18) PCD is polycarbonate diol, and n is the number of repetitions, and the (n+1) Rc's are each independently an alkylene group having 2 to 12 carbon atoms (preferably 3 to 8, more preferably 3 to 6). In compound (18) PCD, the (n+1) Rc's may be the same or different. Compound (19) PCL is polycaprolactone diol, where n and m are the repeating numbers, and Rd is an alkylene group having 2 to 25 carbon atoms.

[0214] Compound containing an active hydrogen group and a polymerizable group Examples of compounds containing an active hydrogen group include compounds containing an active hydrogen group and a polymerizable group. Compounds containing an active hydrogen group and a polymerizable group are suitable as compounds for introducing a polymerizable group into polymer P (hereinafter also referred to as "polymerizable group introducing compounds").

[0215] Specific examples of diol compounds as compounds containing an active hydrogen group and a polymerizable group are shown below, but the compounds containing an active hydrogen group and a polymerizable group are not limited to the following specific examples.

[0216]

[0217] For the compound containing an active hydrogen group and a polymerizable group, the description in paragraphs 0075 to 0089 of WO 2016 / 052053 may be appropriately referred to.

[0218] Compound containing an active hydrogen group and a hydrophilic group: Examples of compounds containing an active hydrogen group include compounds containing an active hydrogen group and a hydrophilic group. Compounds containing an active hydrogen group and a hydrophilic group are suitable as compounds for introducing hydrophilic groups into polymer P (hereinafter also referred to as "hydrophilic group-introducing compounds").

[0219] When a compound containing an active hydrogen group and a hydrophilic group is used as the raw material compound, the polymer P preferably contains the following structural unit (P2).

[0220]

[0221] In the structural unit (P2), L ２１ represents a trivalent organic group having 1 to 20 carbon atoms; L ２２ represents a single bond or a divalent organic group having 1 to 20 carbon atoms; １ represents a carboxy group, a salt of a carboxy group, a sulfo group, or a salt of a sulfo group, and * represents a bonding position.

[0222] L ２１ The number of carbon atoms in the trivalent organic group having 1 to 20 carbon atoms represented by the formula (I) is preferably 2 to 20, more preferably 3 to 20, and even more preferably 4 to 20. ２１ The trivalent organic group represented by the formula (I) is preferably a trivalent hydrocarbon group or a group in which at least one carbon atom in a trivalent hydrocarbon group is replaced with a heteroatom (preferably an oxygen atom, a sulfur atom, or a nitrogen atom).

[0223] L ２２ The number of carbon atoms in the divalent organic group having 1 to 20 carbon atoms represented by the formula (I) is preferably 1 to 10, and more preferably 1 to 6. ２２ The divalent organic group represented by the formula (I) is preferably a divalent hydrocarbon group (preferably an alkylene group) or a group in which at least one carbon atom in a divalent hydrocarbon group (preferably an alkylene group) is substituted with an oxygen atom or a sulfur atom (preferably an oxygen atom). ２２ may be a single bond.

[0224] Specific examples of compounds containing an active hydrogen group and a hydrophilic group are shown below, but the compounds containing an active hydrogen group and a hydrophilic group are not limited to these examples. The carboxyl group and sulfo group in the following specific examples may be neutralized (i.e., may be a salt of the carboxyl group and a salt of the sulfo group), respectively.

[0225]

[0226] For compounds containing an active hydrogen group and a hydrophilic group, the descriptions in paragraphs 0112 to 0118 and 0252 to 0254 of WO 2016 / 052053 can be appropriately referenced.

[0227] The content of polymer P relative to the total solid content of the specific particles is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, even more preferably 30% by mass to 70% by mass, and still more preferably 40% by mass to 60% by mass.

[0228] In the present disclosure, the total solid content of the specific particles means the total amount of the specific particles excluding the solvent (i.e., water and organic solvent). When the specific particles do not contain a solvent, the total solid content of the specific particles is the same as the total amount of the specific particles.

[0229] The content of the polymer P is preferably 0.3% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and even more preferably 1% by mass to 10% by mass, based on the total amount of the ink.

[0230] From the viewpoint of storage stability of the ink, the ratio of the content of the polymerizable compound A to the total content of the polymer P having an acid group and the polymerizable compound A is preferably 0.3 to 0.7, and more preferably 0.4 to 0.6. When the ratio is within this range, the function of the polymer P (the function of retaining the polymerizable compound A within the specific particles; in other words, the function of suppressing the exudation of the polymerizable compound A from the specific particles) is more effectively exhibited.

[0231] (Radical Polymerization Initiator) The specific particles preferably contain at least one type of radical polymerization initiator.

[0232] In the present disclosure, a radical polymerization initiator means a compound that absorbs light to generate radicals.

[0233] When the specific particles contain a radical polymerization initiator, the abrasion resistance and adhesion of the ink film are further improved. This is thought to be because the distance between the polymerizable compound A and the radical polymerization initiator is shortened, thereby improving the curing sensitivity of the ink film (hereinafter also simply referred to as "sensitivity").

[0234] Furthermore, when the specific particles contain a radical polymerization initiator, it is possible to use a radical polymerization initiator that has previously been difficult to use due to its high sensitivity but low dispersibility or solubility in water (for example, a radical polymerization initiator having a solubility in water of 1.0 mass% or less at 25°C). This allows for a wider range of radical polymerization initiators to be used, and therefore a wider range of light sources to be used. As a result, curing sensitivity can be improved compared to conventional methods.

[0235] Specific examples of the above-mentioned radical polymerization initiator, which has high sensitivity but is difficult to use due to its low dispersibility or low solubility in water, include carbonyl compounds and acylphosphine oxide compounds described below, and acylphosphine oxide compounds are preferred.

[0236] By incorporating a radical polymerization initiator having low solubility in water into specific particles, the radical polymerization initiator can be contained in the ink.

[0237] Furthermore, the ink in which the specific particles contain a radical polymerization initiator also has superior storage stability compared to conventional photocurable compositions, which is thought to be because the radical polymerization initiator contained in the specific particles is prevented from aggregating or settling.

[0238] For the radical polymerization initiator, for example, the description in paragraphs 0091 to 0094 of WO 2016 / 052053 can be appropriately referred to.

[0239] The radical polymerization initiator is preferably (a) a carbonyl compound such as an aromatic ketone or (b) an acylphosphine oxide compound. Examples of the radical polymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (e.g., product name "Omnirad 819" manufactured by IGM Resins B.V.), 2-(dimethylamine)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (e.g., product name "Omnirad 369" manufactured by IGM Resins B.V.), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (e.g., product name "Omnirad 907" manufactured by IGM Resins B.V.), and 1-hydroxy-cyclohexyl-phenyl-ketone (e.g., product name "Omnirad 184" manufactured by IGM Resins B.V.). Examples of suitable phosphine oxides include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (e.g., product name "Omnirad TPO-H", manufactured by IGM Resins B.V.), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (e.g., product name "Omnirad TPO-H", manufactured by IGM Resins B.V.), and (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (e.g., product name "Omnirad TPO-L", manufactured by IGM Resins B.V.).

[0240] Among these, from the viewpoint of improving sensitivity and compatibility with LED light, the radical polymerization initiator is preferably an acylphosphine oxide compound (b), and more preferably a monoacylphosphine oxide compound or a bisacylphosphine oxide compound.

[0241] The wavelength of the LED light is preferably 355 nm, 365 nm, 385 nm, 395 nm, or 405 nm.

[0242] The specific particles of the embodiment containing a polymerization initiator can be produced, for example, by emulsifying a mixture of an oil phase component containing a polymer P (or a raw material compound for producing the polymer P), a polymerizable compound A, and a polymerization initiator, and an aqueous phase component.

[0243] The content of the radical polymerization initiator is preferably 0.1% by mass to 15% by mass, more preferably 0.5% by mass to 10% by mass, and even more preferably 1% by mass to 6% by mass, relative to the total solid content of the specific particles.

[0244] The content of the radical polymerization initiator is preferably 0.1% by mass to 3.0% by mass, more preferably 0.3% by mass to 2.0% by mass, and even more preferably 0.5% by mass to 1.5% by mass, relative to the total amount of the ink.

[0245] (Sensitizer) The specific particles preferably contain at least one type of sensitizer.

[0246] When the specific particles contain a photopolymerization initiator, the specific particles preferably contain a sensitizer.

[0247] When the specific particles contain a sensitizer, the decomposition of the photopolymerization initiator due to irradiation with active energy rays can be further accelerated.

[0248] A sensitizer is a substance that absorbs specific active energy rays and becomes electronically excited. The electronically excited sensitizer contacts a photopolymerization initiator and causes electron transfer, energy transfer, heat generation, and other reactions. This promotes chemical changes in the photopolymerization initiator, such as decomposition and the generation of radicals, acids, or bases.

[0249] Examples of sensitizers include benzophenone, thioxanthone, isopropylthioxanthone, anthraquinone, 3-acylcoumarin derivatives, terphenyl, styryl ketone, 3-(aroylmethylene)thiazoline, camphorquinone, eosin, rhodamine, and erythrosin.

[0250] In addition, as the sensitizer, a compound represented by general formula (i) described in JP-A-2010-24276, a compound represented by general formula (I) described in JP-A-6-107718, and the like can also be suitably used.

[0251] Among these, from the viewpoints of compatibility with LED light and reactivity with the photopolymerization initiator, the sensitizer is preferably at least one selected from thioxanthone, isopropylthioxanthone, and benzophenone, more preferably at least one selected from thioxanthone and isopropylthioxanthone, and even more preferably isopropylthioxanthone.

[0252] When the specific particles contain a sensitizer, the content of the sensitizer is preferably 0.1% by mass to 20% by mass, more preferably 0.2% by mass to 15% by mass, and even more preferably 0.3% by mass to 10% by mass, relative to the solid content of the specific particles.

[0253] The content of the sensitizer is preferably 0.01% by mass to 0.5% by mass, more preferably 0.05% by mass to 0.3% by mass, and even more preferably 0.1% by mass to 0.2% by mass, relative to the total amount of the ink.

[0254] The specific particles containing a polymerization initiator and a sensitizer can be produced, for example, by emulsifying a mixture of a polymer P (or a raw material compound for producing the polymer P), a polymerizable compound A, an oil phase component containing a photopolymerization initiator and a sensitizer, and an aqueous phase component.

[0255] (Other Components) The specific particles may contain other components in addition to the above-described components. Examples of the other components include a compound containing at least one selected from the group consisting of a polysiloxane bond (i.e., a divalent polysiloxane group), a monovalent polysiloxane group, a monovalent fluorohydrocarbon group, and a divalent fluorohydrocarbon group.

[0256] (Method for Producing Aqueous Dispersion of Specific Particles) The ink of the present disclosure can be produced by producing an aqueous dispersion of specific particles containing the above-described specific particles and water, and adding other components to the obtained aqueous dispersion as needed.

[0257] Furthermore, since the ink of the present disclosure is in the form of an aqueous dispersion of specific particles, depending on the composition of the ink, it is also possible to produce the ink directly as an aqueous dispersion of specific particles (i.e., without adding other components).

[0258] There is no particular limitation on the method for producing the aqueous dispersion of the specific particles. Examples of the method for producing the aqueous dispersion of the specific particles include the following production method A and production method B.

[0259] - Production Method A - Production Method A includes a step of mixing an oil phase component containing an organic solvent, polymer P, and a polymerizable monomer with an aqueous phase component containing water, and emulsifying the mixture to obtain an aqueous dispersion of specific particles. Production Method A is suitable as a method for producing an aqueous dispersion of specific particles containing polymer P in the form of a chain polymer. For details of Production Method A, reference can be made to publicly known documents such as Japanese Patent No. 6584677.

[0260] - Production Method B - Production Method B includes a step of mixing and emulsifying an oil phase component containing an organic solvent, raw material compounds for polymer P (e.g., a tri- or higher functional isocyanate compound, a compound having two or more active hydrogen groups, etc.), and a polymerizable monomer, with an aqueous phase component containing water, to obtain an aqueous dispersion of specific particles. Production Method B is suitable as a method for producing an aqueous dispersion of specific particles (e.g., microcapsules) containing polymer P in the form of a crosslinked polymer. For details of Production Method B, reference can be made to publicly known documents such as WO 2016 / 052053.

[0261] <Organic Solvent> The ink preferably contains at least one organic solvent (preferably a water-soluble organic solvent), which further ensures the ink ejection properties from the inkjet head.

[0262] In the present disclosure, the term "water-soluble" in "water-soluble organic solvent" means that 1 g or more of the solvent dissolves in 100 g of water at 25° C. The amount of the water-soluble organic solvent that dissolves in 100 g of water at 25° C. is preferably 5 g or more, and more preferably 10 g or more.

[0263] The content of the water-soluble organic solvent is preferably 1% by mass to 35% by mass, more preferably 3% by mass to 30% by mass, even more preferably 5% by mass to 20% by mass, and still more preferably 7% by mass to 15% by mass, relative to the total amount of the ink.

[0264] When the content of the water-soluble organic solvent is 1% by mass or more, the ejection properties of the ink are further improved.

[0265] When the content of the water-soluble organic solvent is 35% by mass or less, the storage stability of the ink is further improved.

[0266] Specific examples of water-soluble organic solvents are as follows: Alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.) Polyhydric alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, 2-methylpropanediol, etc.) Polyhydric alcohol ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.) Amines (e.g., ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.) Amides (for example, formamide, N,N-dimethylformamide, N,N-dimethylacetamide, etc.) Heterocycles (for example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, etc.) Sulfoxides (e.g., dimethyl sulfoxide, etc.) Sulfones (e.g., sulfolane, etc.) Others (urea, acetonitrile, acetone, etc.),

[0267] <Coloring Material> The ink may be an ink containing at least one coloring material (so-called "colored ink"), or an ink containing no coloring material (so-called "clear ink").

[0268] When the ink contains a coloring material, it is preferable that the coloring material be contained outside the specific particles (that is, the specific particles do not contain the coloring material).

[0269] The coloring material is not particularly limited, and can be arbitrarily selected from known coloring materials such as pigments, water-soluble dyes, disperse dyes, etc. Among these, pigments are more preferred as the coloring material in terms of excellent weather resistance and color reproducibility.

[0270] The pigment is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include known organic pigments and inorganic pigments, etc. Further examples of the pigment include resin particles dyed with a dye, commercially available pigment dispersions, and surface-treated pigments (for example, pigments dispersed in water, liquid compounds, insoluble resins, etc. as a dispersion medium, and pigments whose surfaces have been treated with resins, pigment derivatives, etc.).

[0271] Examples of organic pigments and inorganic pigments include yellow pigments, red pigments, magenta pigments, blue pigments, cyan pigments, green pigments, orange pigments, purple pigments, brown pigments, black pigments, and white pigments.

[0272] When a pigment is used as the coloring material, a pigment dispersant may be used as needed. When a pigment is used as the coloring material, a self-dispersing pigment having hydrophilic groups on the surface of the pigment particles may be used as the pigment.

[0273] For colorants and pigment dispersants, reference can be made to paragraphs 0180 to 0200 of JP-A-2014-040529 and paragraphs 0122 to 0129 of WO 2016 / 052053, as appropriate.

[0274] When the ink contains a colorant, the content of the colorant is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass, and particularly preferably 0.5% by mass to 5% by mass, relative to the total amount of the ink.

[0275] <Other Components> The ink may contain other components in addition to those described above, as necessary. The other components may or may not be contained in the specific particles. The ink may contain other components such as a surfactant, a polymerization inhibitor, and an ultraviolet absorber.

[0276] Furthermore, the ink may contain, outside the specific particles, a water-soluble polymerizable monomer, a water-soluble photopolymerization initiator, a water-soluble resin, etc. For details about these components, see, for example, paragraphs 0134 to 0157 of WO 2016 / 052053.

[0277] (Preferred method for producing ink) There are no particular limitations on the method for producing the ink, but a preferred embodiment includes the steps of producing an aqueous dispersion of specific particles by the above-mentioned method for producing an aqueous dispersion (production method A or production method B), and adding other components such as a pigment and a water-soluble organic solvent to the aqueous dispersion of specific particles and mixing them.

[0278] Another embodiment of the method for producing ink is a method in which ink is directly produced as an aqueous dispersion of specific particles by the step of producing an aqueous dispersion of specific particles by the above-mentioned method for producing an aqueous dispersion (production method A or production method B) (i.e., a method in which no other components are added to the aqueous dispersion of specific particles).

[0279] (Preferable physical properties of the ink) The viscosity of the ink at 25°C is preferably 3 mPa·s to 15 mPa·s, and more preferably 3 mPa·s to 13 mPa·s. When the ink viscosity is in the above range, higher ejection stability can be achieved. The ink viscosity is a value measured using a viscometer. As the viscometer, for example, a VISCOMETER TV-22 (Toki Sangyo Co., Ltd.) can be used.

[0280] [Inkjet Recording Method] The inkjet recording method of the present disclosure preferably includes, using the inkjet recording apparatus of the present disclosure and the ink described above, a step of heating a substrate (hereinafter also referred to as a heating step), a step of ejecting the ink onto the substrate (hereinafter also referred to as an "ejecting step"), a step of blowing air onto the surface on which the ink has landed (hereinafter also referred to as an "air blowing step"), and a step of irradiating the surface of the substrate on which the ink has landed with active energy rays (hereinafter also referred to as an "irradiation step").

[0281] Hereinafter, the operation of irradiating with active energy rays may be referred to as "exposure".

[0282] In the inkjet recording method of the present disclosure, the inkjet recording apparatus of the present disclosure is used, and therefore the same effects as those obtained by the inkjet recording apparatus of the present disclosure can be achieved.

[0283] The ink used in the inkjet recording method of the present disclosure is the same as the ink used in the inkjet recording apparatus of the present disclosure, and therefore a description thereof will be omitted.

[0284] In the inkjet recording method of the present disclosure, it is preferred that the ink contains an organic solvent, and that the water content in the ink that has landed on the substrate at the time of irradiation with actinic energy rays is 5% by mass or less relative to the water content at the time of landing on the substrate, and the organic solvent content in the ink that has landed on the substrate at the time of irradiation with actinic energy rays is 30% by mass or more relative to the organic solvent content at the time of landing on the substrate.

[0285] In other words, at the time of irradiation with active energy rays, it is preferable that there is little water remaining in the ink at the time of impacting the ink on the substrate, and it is preferable that a certain amount of organic solvent remains. When the remaining states of water and organic solvent are as described above, seepage of the polymerizable compound A from the specific particles is promoted, the subsequent polymerization reaction easily proceeds, and the image quality, abrasion resistance, and stretchability of the obtained image are further improved.

[0286] Hereinafter, the ratio of the water content at the time of irradiation with active energy rays to the water content at the time of impact on the substrate will be referred to as the "remaining water ratio," and the ratio of the organic solvent content at the time of irradiation with active energy rays to the organic solvent content at the time of impact on the substrate will be referred to as the "remaining organic solvent ratio."

[0287] The lower limit of the remaining water content is not particularly limited and may be 0% by mass, and the upper limit of the remaining organic solvent content is preferably 80% by mass.

[0288] The remaining proportion of water and the remaining proportion of organic solvent are calculated using the following method.

[0289] At the time of irradiation with the active energy rays, the inkjet recording device is stopped, and a measurement sample of 25 mm x 30 mm is cut out.

[0290] - Remaining water ratio - Water content B1 (mg / m ２ ) is measured by a moisture vaporization method using a trace moisture analyzer (product name "CA-200", manufactured by Mitsubishi Chemical Analytical Co., Ltd.). The moisture vaporization temperature is set to 140°C, and a coulometric titration reagent (product name "Aquamicron AKX", manufactured by Mitsubishi Chemical Co., Ltd.) is used as the anolyte, and a coulometric titration reagent (product name "Aquamicron CxU", manufactured by Mitsubishi Chemical Co., Ltd.) is used as the catholyte. Separately, the moisture content B2 (mg / m ) of the substrate before inkjet recording is measured. ２ ) is measured in the same manner as for the water content B1. "B1-B2" is the mass per unit area (mg / m) of water in the ink that has landed on the substrate at the time of irradiation with active energy rays. ２ ) The content of polymerizable compound A contained in the measurement sample is measured using a high performance liquid chromatograph (product name "Prominence (liquid delivery unit: LC-20AT, detector: SPD-M20A)" manufactured by Shimadzu Corporation). The ratio of the content of polymerizable compound A to the content of water is calculated from the ink filled in the ink cartridge. Using the mass per unit area of ​​polymerizable compound A contained in the measurement sample and the above ratio, the mass A (mg / m) of water per unit area in the ink that has landed on the substrate at the time the ink has landed is calculated.２ The remaining percentage of water is calculated based on the following formula: Remaining percentage of water (mass%) = {(B1 - B2) / A} x 100

[0291] - Remaining ratio of organic solvent - The organic solvent contained in the ink that has landed on the substrate is extracted from the surface of the measurement sample on which the ink has landed, using 1 mL of methanol, for 24 hours at 25°C. Using the obtained extract, the mass C (mg / m) per unit area of ​​the organic solvent in the ink that has landed on the substrate at the time of irradiation with active energy rays was measured using a gas chromatograph (product name "GC-2010", manufactured by Shimadzu Corporation). ２ ) is measured. In addition, the content of polymerizable compound A contained in the measurement sample is measured using a high performance liquid chromatograph (product name "Prominence (liquid supply unit: LC-20AT, detector: SPD-M20A)" manufactured by Shimadzu Corporation). The ratio of the content of polymerizable compound A to the content of organic solvent is calculated from the ink filled in the ink cartridge or ink bottle. Using the mass per unit area of ​​polymerizable compound A contained in the measurement sample and the above ratio, the mass per unit area D (mg / m) of the organic solvent in the ink that has landed on the substrate at the time the ink has landed is calculated. ２ The remaining proportion of organic solvent is calculated based on the following formula: remaining proportion of organic solvent (mass%)=(C / D)×100

[0292] <Heating Step> The heating step is a step of heating the substrate. In the heating step, the surface of the substrate opposite to the surface on which the ink lands may be heated, the surface on which the ink lands may be heated, or both surfaces of the substrate may be heated. From the viewpoint of causing the polymerizable compound A to leach out from the particles contained in the ink, it is preferable that the surface of the substrate opposite to the surface on which the ink lands be heated in the heating step. For example, the surface of the substrate opposite to the surface on which the ink lands is heated by a platen arranged below the substrate.

[0293] The substrate may be heated in advance before the ink lands, may be heated at the time the ink lands, may be heated after the ink lands, or any combination thereof.

[0294] From the viewpoint of promoting the seepage of the polymerizable compound A, the substrate is preferably heated in advance before the ink lands on the substrate, and more preferably heated in advance before the ink lands on the substrate and also heated at the time the ink lands on the substrate.

[0295] The heating temperature is preferably 35°C to 60°C, and more preferably 40°C to 50°C.

[0296] <Discharging Step> The discharging step is a step of discharging the ink onto a substrate.

[0297] The ink is ejected by the inkjet recording method using the inkjet recording apparatus of the present disclosure.

[0298] The resolution of the inkjet head is preferably 300 dpi or more, more preferably 600 dpi or more, and even more preferably 800 dpi or more, where dpi (dots per inch) refers to the number of dots per 2.54 cm (1 inch).

[0299] The amount of ink droplets ejected from the inkjet head (amount per dot) is preferably 1 pL (picoliter) to 100 pL, more preferably 3 pL to 80 pL, and even more preferably 3 pL to 50 pL.

[0300] <Air Blowing Step> The air blowing step is a step of blowing air onto the surface on which the ink has landed. By blowing air onto the surface on which the ink has landed, the ink dries more rapidly, and the image quality and abrasion resistance are further improved.

[0301] The temperature of the gas to be blown is, for example, 20°C to 60°C.

[0302] The gas is blown onto the applied ink using a blower provided in the inkjet recording apparatus of the present disclosure.

[0303] <Irradiation Step> The irradiation step is a step of irradiating the surface of the substrate on which the ink has landed with active energy rays (in other words, a step of exposing the ink ejected onto the substrate).

[0304] In this step, the irradiation of active energy rays (i.e., exposure) polymerizes the polymerizable compound A in the ink, curing the ink and obtaining an image. More specifically, as described above, after the ink lands, the polymerizable compound A effectively seeps out from the specific particles, which allows sufficient curing between the specific particles (i.e., bonding between the specific particles), resulting in an image with excellent image quality and scratch resistance.

[0305] The ink ejected onto the substrate may be irradiated with active energy rays in a state where the substrate and the ink ejected onto the substrate are heated. Alternatively, the ink ejected onto the substrate may be irradiated with active energy rays in a state where the substrate and the ink ejected onto the substrate are heated and gas is blown onto the ink ejected onto the substrate by an air blower.

[0306] The irradiation energy (i.e., exposure dose) of the active energy ray was 20 mJ / cm ２ It is preferable that the concentration is 100 mJ / cm or more. ２ More preferably, it is 500 mJ / cm or more. ２ More preferably, it is equal to or greater than this.

[0307] There is no particular upper limit to the exposure dose, and it is 5 J / cm ２ and 1,500 mJ / cm ２ may be.

[0308] The irradiation step may include a step of temporarily curing the ink with a relatively small amount of exposure light and a step of fully curing the ink with a relatively large amount of exposure light. ２ ~500 mJ / cm ２ and preferably 100 mJ / cm ２ ~300 mJ / cm ２ It is more preferable that:

[0309] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0310] "Room temperature" refers to 25°C unless otherwise specified.

[0311] <Preparation of Polymer P> A 1-liter three-neck flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 187.9 g of methyl ethyl ketone, 137.4 g of isophorone diisocyanate, 32.3 g of tricyclodecane dimethanol, 91.8 g of epoxy acrylate (product name "EBECRYL 600" manufactured by Daicel-Allnex Corporation), 28.8 g of 2,2-bis(hydroxymethyl)propionic acid, 25.3 g of a hydroxy group-containing silicone compound (product name "Silaplane FM-DA11" manufactured by JNC Corporation), and 0.01 g of 2-tert-butyl-1,4-benzoquinone, and the mixture was heated to 70°C, followed by the addition of 0.5 g of bismuth tris(2-ethylhexanoate) (product name "Neostan U-600" manufactured by Daicel-Allnex Corporation). The mixture was then stirred for 8 hours while maintaining the temperature inside the reaction vessel at 70°C. Next, a solution consisting of 64.4 g of methyl ethyl ketone and 221.1 g of 2-propanol was added to the reaction vessel and stirred for 2 hours. Thereafter, the temperature was lowered to 40°C, and 27.8 g of N,N-diisopropylethylamine was added. While maintaining the temperature inside the reaction vessel at 40°C, stirring was continued for 1 hour to obtain a polymer P solution (polymer P content: 40 mass%).

[0312] Example 1 Preparation of Aqueous Dispersion of Specific Particles Preparation of Oil Phase Component The following components were mixed and stirred at room temperature for 30 minutes to obtain an oil phase component: 40% by mass solution of polymer P...38.7 g Polymerizable compound A: product name "MIRAMER SC2153", manufactured by Miwon Specialty Chemical Co., Ltd.: 70% by mass of 10-functional urethane acrylate, 30% by mass of dipentaerythritol hexaacrylate (DPHA)...15.5 g Polymerization initiator: (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (product name "Omnirad TPO-L", manufactured by IGM Resins B.V.)...2.5 g Sensitizer: isopropylthioxanthone (ITX)...0.6 g Ethyl acetate...31.7 g Methyl ethyl ketone...9.4 g

[0313] - Preparation of aqueous dispersion of specific particles - The oil phase component and 84.6 g of distilled water were mixed, and the resulting mixture was emulsified at room temperature using a homogenizer at 7,000 rpm for 30 minutes to obtain an emulsion. The resulting emulsion was added to distilled water (30.0 g), and the resulting liquid was heated to 50°C and stirred at 50°C for 4 hours to distill off ethyl acetate and methyl ethyl ketone from the liquid. The liquid from which ethyl acetate and methyl ethyl ketone had been distilled off was diluted with distilled water to a solids concentration of 25% by mass, thereby obtaining an aqueous dispersion of specific particles (content of specific particles: 25% by mass). The volume average dispersed particle diameter of the specific particles was 100 nm.

[0314] <Preparation of Ink> The components were mixed to prepare an ink.

[0315] ・Water dispersion of the above specific particles (content of specific particles: 25% by mass) ... 44 parts by mass ・Pigment dispersion: product name "Pro-jet Black APD4000", manufactured by FUJIFILM Imaging Colorants, pigment concentration 15% by mass, pigment dispersant concentration 6% by mass ... 20 parts by mass ・Surfactant: product name "Emulgen 707", manufactured by Kao Corporation, solid content concentration 100% by mass ... 0.5 parts by mass ・Water ... the remaining amount to make the total ink 100 parts by mass

[0316] [Examples 2 to 14, Comparative Example 1] Aqueous dispersions of specific particles were prepared in the same manner as in Example 1 so that the contents (mass %) of each component contained in the ink were as shown in Tables 1 and 2, and inks were obtained in the same manner as in Example 1. In Examples 7 to 14 and Comparative Example 1, propylene glycol was used as the organic solvent.

[0317] <Image Recording> In Examples 1 to 14, a multi-pass (i.e., shuttle scan) inkjet recording apparatus equipped with a blower, as shown in FIG. 1, was prepared. In Comparative Example 1, a multi-pass (i.e., shuttle scan) inkjet recording apparatus not equipped with a blower, as shown in FIG. 3, was prepared. The distance X1 shown in FIG. 3 was adjusted to the value shown in Tables 1 and 2. Transport rollers for transporting the substrate were installed, and platens 26A, 26B, and 26C shown in FIG. 2 were provided below the transport rollers. The inkjet head shown in FIG. 3 was used. The scanning speed of the inkjet head was set to 1000 mm / sec, and the scanning distance per scan of the inkjet head was set to 1700 mm. Details of the blowers used in Examples 1 to 14 are as follows. Blower a: Blower with a blowing nozzle as shown in FIG. 5C Blower b: Blower with a blowing nozzle as shown in FIG. 5B Blower c: Blower without a blowing nozzle and provided with a rectifying plate 38A as shown in FIG. 6 Blower d: Blower without a blowing nozzle

[0318] The ink cartridge attached to an inkjet recording device was filled with the ink, and an image was recorded on a substrate by the following method: A PVC (polyvinyl chloride) film (product name "LAG Jet P-282ZW", thickness 80 μm, manufactured by Lintec Corporation) was used as the substrate.

[0319] The temperature of platen 26A in FIG. 2 was set to the heating temperature shown in Tables 1 and 2. The heated substrate was transported, and the ink was ejected onto the heated substrate from the inkjet head of the inkjet recording device. The ink ejection conditions were 900 dpi (dots per inch), 10 pL per dot, 8 passes, and bidirectional printing. The temperature of platen 26B in FIG. 2 was set to the heating temperature shown in Tables 1 and 2, and the ink was ejected while heating the substrate and while blowing gas from a blower based on the air blowing conditions described below. The substrate onto which the ink had landed was exposed to light using light source 34 at an exposure dose of 1000 mJ / cm. ２ The exposure was performed while heating the substrate and blowing gas from a blower. Note that in Comparative Example 1, no blower was installed, and therefore no gas was blown during ink ejection and exposure.

[0320] - Air blowing conditions - The outputs of fans a to d were controlled to set the same air volume and air speed. Fans a and b were equipped with air blowing nozzles, and fan c was equipped with an air straightening plate, so that the air speeds at points A and B were adjusted to the values ​​shown in Tables 1 and 2.

[0321] The image quality, abrasion resistance, and stretchability of the obtained image recording material were evaluated. The ejection properties of the image recording material were also evaluated. The evaluation methods were as follows.

[0322] <Image Quality> Using the inks prepared and stored at room temperature for less than one day, character images shown in FIG. 10 were recorded in 4-point, 5-point, and 6-point sizes under the image recording conditions described above. The character images of each size were observed using a 10x craft loupe (manufactured by Etsumi Co., Ltd.). Based on the observation results, the image definition was evaluated using the following evaluation criteria. The evaluation criteria are as follows: A, B, and C are levels that are acceptable for practical use. A: No disruption, crushing, or bleeding was observed in the 4-point character image shown in FIG. 10. B: No disruption, crushing, or bleeding was observed in the 5-point character image shown in FIG. 10 (excluding cases falling under A). C: No disruption, crushing, or bleeding was observed in the 6-point character image shown in FIG. 10 (excluding cases falling under A and B). D: At least one of disruption, crushing, and bleeding was observed in the 6-point character image shown in FIG. 10.

[0323] <Abrasion Resistance> Using the above-described image recording method, a 100 mm x 30 mm rectangular solid image was recorded on a substrate at 100% recording duty to obtain an image recording. The obtained image recording was left for 24 hours in an environment of 25°C and 50% relative humidity. After leaving the image recording, a cotton cloth (Kanakin No. 3) was placed on the image recording surface of the image recording, and the image recording was rubbed 100 times back and forth under a load of 500 g using a Gakushin-type abrasion tester (manufactured by TESTER SANGYO CO., LTD.). After rubbing, the image recording surface was visually observed to confirm the presence of abrasions and the state of image peeling. The evaluation criteria are as follows: Ratings 3, 4, and 5 are acceptable for practical use. 5: No abrasions were observed on the image. 4: Abrasions were observed on the image, but did not reach the substrate. 3: Scratches were left on the image, and some of the scratches reached the substrate, but the area where the substrate was visible was smaller than the area of ​​the image at the time of recording (30 cm ２ 2: The image has scratches, some of which reach the substrate, and the area where the substrate is visible is greater than or equal to the area of ​​the image at the time of recording (30 cm). ２1: The image has scratches, some of which reach the substrate, and the area where the substrate is visible is 5% or more and less than 50% of the area of ​​the image at the time of recording (30 cm ２ ) is more than 50%.

[0324] <Stretchability> Using the image recording method described above, a 100 mm x 30 mm rectangular solid image was recorded on a substrate at 100% recording duty to obtain an image recording. The obtained image recording was left for 24 hours in an environment of 25°C and 50% relative humidity. The image density of the image recording after leaving (i.e., the image recording before stretching) was measured using a fluorescence spectrodensitometer (product name "FD-7", manufactured by Konica Minolta Japan, Inc.). The image recording after leaving was set to a gripping distance of 5 cm using a tensile tester (product name "Autograph AG-IS 5kN Type", manufactured by Shimadzu Corporation) and stretched at a stretching speed of 300 mm / min until the gripping distance became 13 cm. The image density of the stretched image recording was measured in the same manner as the image density of the image recording before stretching. The stretched image recording was also visually observed to confirm the presence or absence of cracks. The stretchability was evaluated based on the amount of change in image density between the image recorded material after stretching and the image density of the image recorded material before stretching, and the presence or absence of cracks. The evaluation criteria are as follows. Ratings 3, 4, and 5 are at levels that are acceptable for practical use. Amount of change in image density before and after stretching = Image density of image recorded material before stretching - Image density of image recorded material after stretching 5: No image cracks are observed after stretching, and the amount of change in image density before and after stretching is less than 0.3. 4: No image cracks are observed after stretching, and the amount of change in image density before and after stretching is 0.3 or more and less than 0.6. 3: No image cracks are observed after stretching, and the amount of change in image density before and after stretching is 0.6 or more and less than 0.9. 2: No image cracks are observed after stretching, but the amount of change in image density before and after stretching is 0.9 or more. 1: Image cracks are observed after stretching.

[0325] <Ejectability> The ink prepared and stored at room temperature for less than one day was ejected from the inkjet head of the inkjet recording device for 30 minutes, and then ejection was stopped. Five minutes after ejection was stopped, the ink was ejected again from the inkjet head onto a substrate to record a 5 cm x 5 cm solid image. The resulting image was visually observed to check for missing dots due to non-ejecting nozzles, etc., and the ink ejectability was evaluated according to the following evaluation criteria. The evaluation criteria were as follows. Ratings A and B indicate levels that are acceptable for practical use.

[0326] A: No missing dots due to non-ejecting nozzles, etc. were observed, and a good image was obtained. B: A small amount of missing dots due to non-ejecting nozzles, etc. was observed, but at a level that was not problematic for practical use. C: Missing dots due to non-ejecting nozzles, etc. were observed, and the image was not suitable for practical use.

[0327] The evaluation results are shown in Tables 1 and 2. In Tables 1 and 2, point A is the position where the nozzle row 61Ma is arranged. Point B, as shown in FIG. 7, is a position on the substrate 12 150 mm away from point APa in a direction parallel to the scanning direction (Y direction) toward the blower 33A. Distance X1 refers to the distance along the conveying direction between the end of the nozzle 70 on the downstream side of the conveying direction and the end of the light source 34 on the upstream side of the conveying direction. "Polymerizable compound A / (polymer P + polymerizable compound A)" ​​refers to the mass ratio of the content of polymerizable compound A to the total content of polymer P and polymerizable compound A. "Remaining water ratio" refers to the ratio of the content of water at the time of irradiation with active energy rays to the content of water at the time of impact on the substrate. "Remaining organic solvent ratio" refers to the ratio of the content of organic solvent at the time of impact on the substrate to the content of organic solvent at the time of impact on the substrate. The methods for calculating the remaining water ratio and the remaining organic solvent ratio are as described above.

[0328]

[0329]

[0330] As shown in Tables 1 and 2, in Examples 1 to 14, the inkjet recording apparatus was provided with a blower means that was scanned in conjunction with the inkjet head and was used to blow gas onto the surface on which the ink had landed. Therefore, it was found that the image quality, abrasion resistance, and stretchability of the obtained image were excellent.

[0331] On the other hand, in Comparative Example 1, since no air blowing means was provided, it was found that the image quality, abrasion resistance, and stretchability were poor.

[0332] In Example 6, the air blowing means controlled the wind speed at point A to 2 m / s or less and the wind speed at point B to 4 m / s or more, and it was found that the image quality and dischargeability were superior to those of Example 3, and the abrasion resistance and stretchability were superior to those of Example 4.

[0333] In Example 7, the air blowing means controlled the wind speed at point A to 1 m / s or less and the wind speed at point B to 4 m / s or more, and it was found that the discharge performance was superior to that of Example 6.

[0334] In Example 6, the distance X1 was 40 mm or more, and it was found that the abrasion resistance and stretchability were superior to those of Example 5.

[0335] In Example 6, the heating temperature was 35° C. to 60° C., and it was found that the abrasion resistance and stretchability were superior compared to Examples 1 and 2.

[0336] The disclosure of Japanese Patent Application No. 2024-025794, filed on February 22, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. An inkjet recording device comprising: an inkjet head having at least one nozzle for ejecting an ink containing water and particles containing a polymer P having an acid group and a polymerizable compound A onto a substrate; scanning means for scanning the inkjet head in a scanning direction; transport means for transporting the substrate in a transport direction intersecting the scanning direction; heating means for heating the substrate; air blowing means that is scanned in conjunction with the inkjet head and blows air toward the surface of the substrate on which the ink has landed; and a light source that, after the ink ejected from the nozzle has landed on the substrate, irradiates the surface of the substrate on which the ink has landed with active energy rays.

2. The inkjet recording device according to claim 1, wherein, when the end of the nozzle closest to the air blowing means of the at least one nozzle is defined as point A, and a position on the substrate 150 mm away from point A toward the air blowing means in a direction parallel to the scanning direction, is defined as point B, the air blowing means blows air at a wind speed of 2 m / s or less at point A and a wind speed of 4 m / s or more at point B.

3. The inkjet recording apparatus according to claim 2, wherein the air blowing means blows air at a speed of 1 m / s or less at point A and at a speed of 4 m / s or more at point B.

4. The inkjet recording apparatus according to claim 1, wherein the distance along the transport direction between the downstream end of the nozzle in the transport direction and the upstream end of the light source in the transport direction is 40 mm or more.

5. The ink jet recording apparatus according to claim 1, wherein said heating means heats at a temperature of 35°C to 60°C.

6. An inkjet recording method using the inkjet recording apparatus and the ink described in any one of claims 1 to 5, comprising the steps of: heating the substrate; ejecting the ink onto the substrate; blowing air onto the surface on which the ink has landed; and irradiating the surface of the substrate on which the ink has landed with the active energy rays.

7. The inkjet recording method according to claim 6, wherein the ink further contains an organic solvent, and the water content in the ink that has landed on the substrate at the time of irradiation with the active energy rays is 5% by mass or less relative to the water content at the time of landing on the substrate, and the organic solvent content in the ink that has landed on the substrate at the time of irradiation with the active energy rays is 30% by mass or more relative to the organic solvent content at the time of landing on the substrate.

8. The inkjet recording method according to claim 6, wherein the mass ratio of the content of the polymerizable compound A to the total content of the polymer P having an acid group and the polymerizable compound A is 0.3 to 0.7.

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