Inkjet recording apparatus and inkjet recording method

Abstract

An inkjet recording apparatus and an application thereof, the inkjet recording apparatus including: an inkjet head having a nozzle for discharging, onto a substrate, an ink including water and particles including a polymer P having an acid group and a polymerizable compound A; a scanning mechanism that causes the inkjet head to scan in a scanning direction; a transport mechanism that transports the substrate in a transport direction that intersects the scanning direction; a heating mechanism for heating a surface on the substrate opposite to the surface on which the ink is landed; and a light source that, after the ink ejected from the nozzle falls on the substrate, irradiates an active energy ray on a surface on which the ink falls on the substrate, the distance in the conveyance direction between an end portion of the nozzle on the downstream side in the conveyance direction and an end portion of the light source on the upstream side in the conveyance direction being 10-200 mm.

Description

Technical Field

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

[0002] Conventionally, various studies have been made on inkjet recording apparatuses and inkjet recording methods.

[0003] For example, Japanese Patent No. 6584677 discloses an inkjet ink composition containing water, a chain polymer containing specific structural unit (1), specific structural unit (2), and a hydrophilic group, and particles containing a polymerizable group.

[0004] Japanese Unexamined Patent Application Publication No. 2013-78862 discloses an inkjet recording apparatus including: an inkjet head having a plurality of nozzles for ejecting an ink that is cured by irradiation with activating light; a recording medium conveyance mechanism for conveying a recording medium to which ink droplets ejected from the inkjet head adhere; a scanning mechanism for relatively moving the inkjet head with respect to the recording medium; a pre-curing mechanism that moves together with the inkjet head by the scanning mechanism and irradiates activating light to an extent that the ink droplets adhered to the recording medium are not completely cured; and a formal curing mechanism that is provided separately from the pre-curing mechanism, performs additional exposure on the ink droplets exposed by the pre-curing mechanism, and irradiates activating light to formally cure the ink droplets. Summary of the Invention

[0005] Technical Problem to be Solved by the Invention

[0006] However, conventionally, it has been difficult to achieve both good image quality, rubfastness, and stretchability of an image in an image recording object obtained by an inkjet recording method.

[0007] The present invention has been made in view of such circumstances, and a problem to be solved by an embodiment of the present invention is to provide an inkjet recording apparatus and an inkjet recording method capable of recording an image excellent in image quality, rubfastness, and stretchability.

[0008] Means for Solving the Technical Problem

[0009] The present invention includes the following aspects.

[0010] <1>

[0011] An inkjet recording apparatus including:

[0012] an inkjet head having nozzles for ejecting an ink containing water and particles containing a polymer P having an acid group and a polymerizable compound A onto a substrate;

[0013] a scanning mechanism for scanning the inkjet head in a scanning direction;

[0014] A conveying mechanism that conveys a base material in a conveying direction that intersects the scanning direction;

[0015] A heating mechanism for heating the surface of the base material on the side opposite to the surface where the ink lands; and

[0016] A light source that irradiates the surface of the base material where the ink lands with active energy rays after the ink ejected from the nozzle lands on the base material,

[0017] The distance in the conveying direction between the end on the downstream side in the conveying direction of the nozzle and the end on the upstream side in the conveying direction of the light source is 10 mm to 200 mm.

[0018] <2>

[0019] The inkjet recording apparatus according to <1>, wherein

[0020] The distance is 40 mm to 150 mm.

[0021] <3>

[0022] The inkjet recording apparatus according to <1> or <2>, wherein

[0023] The heating mechanism performs heating at a temperature of 35°C to 60°C.

[0024] <4>

[0025] The inkjet recording apparatus according to any one of <1> to <3> further includes:

[0026] A blower for spraying gas onto the surface of the base material where the ink lands.

[0027] <5>

[0028] An inkjet recording method that uses the inkjet recording apparatus and ink according to any one of <1> to <4>, the inkjet recording method including:

[0029] A step of heating the surface of the base material on the side opposite to the surface where the ink lands;

[0030] A step of ejecting ink onto the base material; and

[0031] A step of irradiating the surface of the base material where the ink lands with active energy rays.

[0032] <6>

[0033] The inkjet recording method according to <5>, wherein

[0034] The ink further contains an organic solvent,

[0035] The water content in the ink landed on the substrate at the time of irradiating the active energy ray is 5% by mass or less relative to the water content at the time of landing on the substrate.

[0036] And the content of the organic solvent in the ink landed on the substrate at the time of irradiating the active energy ray is 30% by mass or more relative to the content of the organic solvent at the time of landing on the substrate.

[0037] <7>

[0038] According to the inkjet recording method described in <5> or <6>, wherein

[0039] 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.

[0040] Advantageous Effects of the Invention

[0041] According to the present invention, there are provided an inkjet recording apparatus and an inkjet recording method capable of recording an image excellent in image quality, rub resistance, and stretchability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is an external perspective view of an inkjet recording apparatus in one embodiment of the present invention.

[0043] Figure 2A schematically shows Figure 1 an explanatory view of a substrate conveyance path of the inkjet recording apparatus shown.

[0044] Figure 2B is for explaining Figure 2A a modified example of the blower shown.

[0045] Figure 2C is for explaining Figure 2A a modified example of the blower shown.

[0046] Figure 3A is a plan perspective view showing an arrangement structure of an inkjet head and a light source.

[0047] Figure 3B is a plan perspective view showing an arrangement structure of an inkjet head and a light source.

[0048] Figure 4A is a plan perspective view showing a nozzle arrangement of an inkjet head.

[0049] Figure 4B is a plan perspective view showing a nozzle arrangement of an inkjet head.

[0050] Figure 5 is a top view showing a structural example of a light source.

[0051] Figure 6 It is a perspective view showing the arrangement structure of an inkjet head and a light source.

[0052] Figure 7 It is a block diagram showing the main part structure of the control system of an inkjet recording apparatus.

[0053] Figure 8 It is a diagram of a character image showing the evaluation of the fineness of an image in an embodiment. Detailed Description of the Invention

[0054] In the present invention, a numerical range represented by "~" means a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0055] In the present invention, when there are a plurality of substances corresponding to each component in a composition, unless otherwise specified, the amount of each component in the composition means the total amount of the plurality of substances present in the composition.

[0056] In the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described within a certain numerical range can be replaced with the upper limit value or the lower limit value of other stepwise described numerical ranges, and can also be replaced with the value shown in the examples.

[0057] In the present invention, the term "process" includes not only independent processes, but also includes this term even when it cannot be clearly distinguished from other processes as long as the desired purpose of the process can be achieved.

[0058] In the present invention, "*" in a chemical formula indicates the bonding position.

[0059] In the present invention, the concept of "image" includes not only pattern images (e.g., characters, symbols, or graphics), but also solid images.

[0060] In the present invention, "light" is a concept including active energy rays such as gamma rays, beta rays, electron beams, ultraviolet rays, and visible light.

[0061] In the present invention, ultraviolet rays are sometimes referred to as "UV (Ultra Violet: ultraviolet) light".

[0062] In the present invention, the light generated from an LED (Light Emitting Diode) light source is sometimes referred to as "LED light".

[0063] In the present invention, “(meth)acrylic acid” is a concept encompassing both acrylic acid and methacrylic acid, “(meth)acrylate” is a concept encompassing both acrylate and methacrylate, and “(meth)acryloyl” is a concept encompassing both acryloyl and methacryloyl.

[0064] In each of the drawings shown in the present invention, each element is not necessarily to an accurate scale, with the emphasis on clearly showing the principle of the present invention, and there are also emphasized parts. Also, components denoted by the same reference signs in the drawings refer to the same components.

[0065] [Inkjet recording device]

[0066] The inkjet recording device of the present invention includes: an inkjet head having nozzles 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 mechanism for scanning the inkjet head in a scanning direction; a conveying mechanism for conveying the substrate in a conveying direction intersecting the scanning direction; a heating mechanism for heating the side of the substrate opposite to the surface on which the ink lands; and a light source for irradiating the surface of the substrate on which the ink lands with active energy rays after the ink ejected from the nozzles lands on the substrate, and the distance in the conveying direction between the downstream end of the inkjet head in the conveying direction and the upstream end of the light source in the conveying direction is 10 mm to 200 mm.

[0067] By using the inkjet recording device of the present invention, an image excellent in recording image quality, rub resistance, and stretchability can be recorded. The reasons for achieving this effect are presumably as follows.

[0068] In image recording by the method of landing an inkjet ink containing water and particles containing a polymer and a polymerizable compound on a substrate and curing the landed ink by irradiation with active energy rays, it is difficult to balance image quality, rub resistance, and stretchability.

[0069] The inkjet recording device of the present invention includes: a heating mechanism for heating the side of the substrate opposite to the surface on which the ink lands; and a light source for irradiating the surface of the substrate on which the ink lands with active energy rays after the ink ejected from the nozzles lands on the substrate, and after the ink is dried by the heating mechanism, the ink is cured by the light source. In particular, by setting the distance in the conveying direction between the downstream end of the inkjet head in the conveying direction and the upstream end of the light source in the conveying direction to be 10 mm to 200 mm, the landing interference between inks is suppressed by the heating mechanism. Also, by setting the above distance to be 10 mm to 200 mm, the polymerizable compound A exudes well from the particles contained in the ink, thereby promoting the polymerization of the polymerizable compound A and achieving excellent rub resistance and stretchability.

[0070] On the other hand, in Japanese Patent Publication No. 6584677, only particles containing polymerizable monomers are disclosed, and the specific structure of the inkjet recording device is not described. In Japanese Patent Laid-Open No. 2013-78862, particles containing polymerizable compounds are not disclosed, which is different from the technical idea of the present invention.

[0071] Hereinafter, an example of the inkjet recording device of the present invention will be described with reference to the accompanying drawings.

[0072] Figure 1 It is a perspective external view of the inkjet recording device 10 in an embodiment of the present invention. The inkjet recording device 10 is a device for applying ink to a substrate by an inkjet recording method.

[0073] The inkjet recording device 10 includes a device main body 20 and support legs 22 for supporting the device main body 20. On the device main body 20, there are provided: platen presses 26A (not shown), 26B, 26C; a carriage 30 on which an inkjet head 24 and light sources 34A, 34B are mounted; a guide mechanism 28 as a mechanism (scanning mechanism) for moving the carriage 30; and a blower 33 (not shown).

[0074] In the present invention, the direction (Y direction) in which the carriage 30 reciprocates is referred to as the "scanning direction".

[0075] In the present invention, the direction (X direction) in which the substrate 12 is conveyed is referred to as the "conveying direction".

[0076] The scanning direction intersects with the conveying direction, and preferably is orthogonal.

[0077] The guide mechanism 28 is arranged to extend along the scanning direction (Y direction) of the carriage 30. The carriage 30 is supported so as to be able to reciprocate in the scanning direction (Y direction) along the guide mechanism 28.

[0078] The inkjet head 24, light sources 34A, 34B disposed 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 inkjet head 24. Also, the scanning distance of the carriage 30 each time (one-way moving distance along the scanning direction) is the same as the scanning distance of the inkjet head 24.

[0079] The scanning speed of the carriage 30 is not particularly limited, and from the viewpoint of further improving the image quality, rub resistance and stretchability of the obtained image, it is preferably set to 500 mm / second to 2000 mm / second.

[0080] The scanning distance of the carriage 30 each time is not particularly limited, and is preferably 100 mm to 6000 mm, more preferably 500 nm to 6000 nm, and further preferably 1200 nm to 6000 nm.

[0081] In Figure 1 Figure 1 , an installation portion 38 for an ink cartridge 36 is provided on the front surface on the left side facing the front surface of the apparatus main body 20. The ink cartridge 36 is a replaceable ink supply source (ink tank) that stores ink. The ink cartridge 36 is provided corresponding to the ink used in the inkjet recording apparatus 100. Each ink cartridge 36 for each color is connected to the inkjet head 24 through an ink supply path (not shown) formed independently.

[0082] Figure 2A is schematically showing Figure 1 an explanatory view of the substrate conveyance path of the inkjet recording apparatus shown in Figure 2B and Figure 2C is for explaining Figure 2A a modified example of the blower shown in

[0083] As Figure 2A shown, the inkjet recording apparatus 10 is provided with: platen presses 26A, 26B, 26C as a heating mechanism for heating the substrate 12; a temperature adjustment unit 50 that adjusts the temperatures of the platen presses 26A, 26B, 26C; and a blower 33A as a mechanism for jetting gas onto the surface where the ink lands on the substrate.

[0084] The platen press 26A is disposed in a region upstream of the inkjet head 24. By disposing the platen press 26A, the substrate 12 can be heated before image recording.

[0085] The platen press 26B is disposed in a region including directly below the inkjet head 24. By disposing the platen press 26B, the substrate 12 can be heated during image recording.

[0086] The platen press 26C is disposed in a region downstream of the inkjet head 24. By disposing the platen press 26C, the substrate 12 can be heated after image recording.

[0087] In the inkjet recording apparatus of the present invention, it is sufficient to heat the substrate 12 by at least one of the platen presses 26A, 26B, and 26C.

[0088] In the inkjet recording apparatus of the present invention, it is preferable to set the temperature of at least one of the platen presses 26A, 26B, and 26C to 35°C to 60°C. In particular, from the viewpoints of improving the image quality, rub resistance, and stretchability of the obtained image, it is preferable to set the temperature of the platen press 26A to 35°C to 60°C, and more preferably to set the temperatures of the platen press 26A and the platen press 26B to 35°C to 60°C.

[0089] The temperature adjustment unit 50 can independently adjust the temperatures of the platen presses 26A, 26B, and 26C.

[0090] The air blowers 33A, 33B, and 33C are mechanisms for jetting gas onto the surface where the ink lands on the substrate. The air blowers are preferably arranged above the inkjet head 24 or on the upstream side of the inkjet head 24 in the conveying direction. The air blower 33A is arranged above the inkjet head 24. The air blowers 33B and 33C are arranged on the upstream side of the inkjet head 24 in the conveying direction. The type of gas jetted by the air blowers 33A, 33B, and 33C is not particularly limited and may be air inhaled from the outside. The temperature of the jetted gas is, for example, 20°C to 60°C.

[0091] As the air blower, an axial flow fan type (refer to Figure 2B ) or a cross flow fan type (refer to Figure 2C ) is preferably used. The air blowing is preferably performed in a curtain shape over the width of the substrate in the inkjet recording apparatus. Therefore, in the axial flow fan type, it is preferable to arrange a plurality of fans in the horizontal direction. Also, in the cross flow fan type, it is preferable to arrange a fan having a length capable of blowing air over the entire width of the substrate. It is preferable to continuously blow air during the ink ejection to form a laminar flow on the substrate surface.

[0092] The air blowers 33A, 33B, and 33C are preferably arranged at a certain angle so that the air flow direction is the outlet side in the conveying direction. The wind speed is, for example, 1.0 m / s to 5.0 m / s.

[0093] By the gas jetted from the air blowers 33A, 33B, and 33C, not only can the ink be dried, but also the inkjet head 24 can be cooled.

[0094] In addition, in Figures 2A to 2C , one air blower is arranged for each, but a plurality of air blowers may also be arranged in the inkjet recording apparatus. For example, the air blower 33A and the air blower 33B may be combined and arranged above the inkjet head 24 and on the upstream side of the inkjet head 24 in the conveying direction.

[0095] A pair of pinch rollers 40 are arranged between the platen 26A and the platen B, and the pair of pinch rollers 40 is a conveying mechanism for intermittently conveying the substrate 12. The pinch rollers 40 move the substrate 12 on the platens 26A, 26B, and 26C in the conveying direction (X direction).

[0096] A guide 46 for the substrate 12 is provided in a region on the downstream side of the inkjet head 24. The guide 46 is a mechanism for suppressing the deviation in the conveying direction.

[0097] A supply roller 42 around which the substrate supplied in the conveying direction is wound is provided on the back side of the inkjet recording apparatus 100. The supply roller 42 is rotatably supported by a frame member (not shown).

[0098] On the front side of the inkjet recording apparatus 100, a take-up roller 44 for taking up the substrate 12 after image recording is provided. The take-up roller 44 is rotatably supported by a frame member (not shown).

[0099] Hereinafter, the details of the inkjet head 24 and the light sources 34A and 34B will be described.

[0100] Figure 3A and Figure 3B is a plan perspective view showing an example of the arrangement of the inkjet head 24 and the light sources 34A and 34B.

[0101] (Inkjet head)

[0102] In the inkjet head 24, nozzle arrays 61W, 61M, 61Lm, 61C, 61Lc, 61Y, 61K, and 61CL for ejecting the inks of respective colors of white (white) ink (W) (CL), yellow (Y), magenta (M), cyan (C), black (K), light cyan (Lc), light magenta (Lm), and transparent (transparent) ink are provided. In Figure 3A and Figure 3B the nozzle arrays are illustrated by dotted lines, and the individual illustration of the nozzles is omitted. Also, in the following description, the nozzle arrays 61W, 61M, 61Lm, 61C, 61Lc, 61Y, 61K, and 61CL may be collectively referred to by the symbol 61 to represent the nozzle arrays.

[0103] In the present invention, the types of inks are not particularly limited. For example, it may be a mode of omitting the nozzle arrays of Lc and Lm, a mode of omitting either one of the nozzle arrays of CL and W, a mode of adding a nozzle array for metallic ink, a mode of having a nozzle array for metallic ink instead of the nozzle array of W, a mode of adding a nozzle array for ejecting an ink of a special color, etc. Also, the arrangement order of the nozzle arrays for each color is not particularly limited.

[0104] By forming nozzle columns 61 for each color to constitute a head module and arranging them, an inkjet head 24 capable of performing color printing can be constituted. For example, it may also be a configuration in which a head module 24Y having a nozzle column 61Y for ejecting yellow ink, a head module 24M having a nozzle column 61M for ejecting magenta ink, a head module 24C having a nozzle column 61C for ejecting cyan ink, a head module 24K having a nozzle column 61K for ejecting black ink, and head modules 24Lc, 24Lm, 24CL, and 24W each having a nozzle column 61Lc, 61Lm, 61CL, and 61W for ejecting inks of respective colors of Lc, Lm, CL, and W are arranged at equal intervals in a manner along the scanning direction (Y direction) of the carriage 30. It may also be configured such that ink flow paths are separately formed for each color inside one inkjet head 24, and a nozzle column for ejecting inks of multiple colors with one head is provided.

[0105] Each nozzle column 61 is a nozzle column in which a plurality of nozzles are arranged at a constant interval in the conveyance direction (X direction).

[0106] Figure 4A and Figure 4B is a plan perspective view showing the nozzle arrangement of the inkjet head 24. As Figure 4A shown, a plurality of nozzles 70 may be arranged in a single row. And, as Figure 4B shown, a plurality of nozzles 70 may be arranged in two rows in an alternately offset state.

[0107] (Light source)

[0108] Light sources 34A, 34B, and 34C are light sources for irradiating active energy rays.

[0109] Examples of the light source 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).

[0110] Among them, the light source is preferably a metal halide lamp, high-pressure mercury lamp, medium-pressure mercury lamp, low-pressure mercury lamp, or UV-LED (hereinafter, also referred to as a UV-LED) as a light source for ultraviolet irradiation.

[0111] The peak wavelength of ultraviolet rays is, for example, preferably 200 nm to 405 nm, more preferably 220 nm to 400 nm, and still more preferably 340 nm to 400 nm.

[0112] As the peak wavelength of the light from the LED light source (LED light), it is preferably 200 nm to 600 nm, more preferably 300 nm to 450 nm, further preferably 320 nm to 420 nm, further preferably 340 nm to 405 nm, and further preferably 355 nm, 365 nm, 385 nm, 395 nm, or 405 nm.

[0113] As the UV-LED, for example, a UV-LED manufactured by NICHIACORPORATION whose main emission spectrum has a wavelength between 365 nm and 420 nm can be cited.

[0114] In addition, a UV-LED that emits actinic rays with a release center between 300 nm and 370 nm as described in U.S. Patent No. 6,084,250 can also be cited.

[0115] Moreover, by combining several UV-LEDs, it is possible to irradiate ultraviolet rays in different wavelength regions.

[0116] The light sources 34A, 34B, and 34C are preferably arranged such that a plurality of light source elements are arranged at constant intervals along the scanning direction (Y direction). As the light source element, for example, a UV-LED element can be cited.

[0117] Figure 5 It is a top view showing a structural example of the light sources 34A and 34B.

[0118] In Figure 5 the light sources 34A and 34B include 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 in an alternately staggered state.

[0119] The illuminance of the light sources 34A, 34B, and 34C is, for example, 500 mW to 15000 mW.

[0120] (Distance between the nozzle and the light source)

[0121] Figure 6 It is a perspective view showing the arrangement structure of the inkjet head and the light source.

[0122] In the inkjet recording apparatus 10 of the present invention, the distance in the transport direction (hereinafter referred to as "distance X1") between the end portion on the downstream side in the transport direction of the nozzle 70 and the end portion on the upstream side in the transport direction of the light source is 10 mm to 200 mm.

[0123] Specifically, the distance X1 refers to Figure 6 the distance in the transport direction (X direction) between the straight line D1 and the straight line D2 in

[0124] As shown in Figure 4A andFigure 4B As shown, the straight line D1 is a straight line parallel to the scanning direction passing through the center of the nozzle 70 located on the most downstream side in the conveying direction among the nozzles 70 included in the nozzle row 61.

[0125] As Figure 5 shown, the straight line D2 is a straight line parallel to the scanning direction passing through the center of the light source element 35 located on the most upstream side in the conveying direction among the light source elements 35 included in the light source 34A.

[0126] In addition, the "downstream side" refers to the side facing the conveying direction. The "upstream side" refers to the side facing the direction opposite to the conveying direction.

[0127] By setting the distance X1 to be 10 mm to 200 mm, the image quality, rub resistance, and stretchability of the obtained image are excellent. It is considered that this is because the volatile components contained in the ink landing on the substrate evaporate, the landing interference between inks is suppressed, and the polymerizable compound A sufficiently exudes from the particles contained in the ink, thereby promoting the polymerization of the polymerizable compound A. From the viewpoint of further improving the image quality, rub resistance, and stretchability of the obtained image, the straight line X1 is preferably 40 mm to 150 mm, more preferably 60 mm to 100 mm.

[0128] The position of the light source relative to the inkjet head is not particularly limited as long as the distance X1 becomes a configuration relationship of 10 nm to 200 nm. As Figure 3A shown by the light sources 34A and 34B, they may also be arranged at both ends in the scanning direction relative to the inkjet head 24. And, as Figure 3B shown by the light source 34C, it may also be arranged at a position separated from the inkjet head 24 in the conveying direction.

[0129] Figure 7 is a block diagram showing the main part structure of the control system of the inkjet recording apparatus 10. As Figure 7 shown, the inkjet recording apparatus 10 is provided with a control device 102 as a control mechanism.

[0130] As the control device 102, for example, a computer equipped with a central processing unit (CPU) can be used. The control device 102 functions as a control device that controls the entire inkjet recording apparatus 10 according to a prescribed program, and also functions as an arithmetic device that performs various operations. The control device 102 includes a substrate conveyance control section 104, a carriage drive control section 106, a blower control section 108, a light source control section 109, an image processing section 110, and an ejection control section 112. These sections are implemented by a hardware circuit, software, or a combination thereof.

[0131] The substrate conveyance control unit 104 controls the conveyance drive unit 114 that conveys the substrate 12. The conveyance drive unit 114 includes a drive motor for driving the nip rollers 40 shown in FIG. 2 and its drive circuit. The substrate 12 conveyed onto the platen disks 26A, 26B, and 26C is intermittently conveyed in the conveyance direction in synchronization with the reciprocating movement in the scanning direction of the inkjet head 24.

[0132] The carriage drive control unit 106 controls the scanning drive unit 116 that moves the carriage 30 in the scanning direction. The scanning drive unit 116 includes a drive motor connected to the movement mechanism of the carriage 30 and its control circuit.

[0133] The blower control unit 108 is a mechanism that controls the operation of the blower via the blower drive circuit 118.

[0134] The light source control unit 109 is a control mechanism that controls the light emission of the light source elements of the light sources 34A and 34B via the element drive circuit 119.

[0135] 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 mechanism that inputs an external operation signal based on manual operation into the control device 102, and various methods such as a keyboard, a mouse, a touch panel, and operation buttons can be adopted, for example. The display device 122 can adopt various methods such as a liquid crystal display, an organic EL display, and a CRT. By operating the input device 120, an operator can select a drawing mode, input printing conditions, and input / edit additional information, etc., and various information such as input contents and search results can be confirmed by the display of the display device 122.

[0136] Furthermore, an information storage unit 124 that stores various information and an image input interface 126 for reading print image data are provided in the inkjet recording apparatus 10. The image input interface can apply a serial interface or a parallel interface. A buffer memory (not shown) for accelerating communication can be mounted in this part.

[0137] The image data input via the image input interface 126 is converted into print data (dot data) in the image processing unit 110. The dot data is usually generated by performing color conversion processing and halftone processing on multi-gray-scale image data. The color conversion processing is a process of converting image data expressed by sRGB, etc. (for example, 8-bit image data for each of the RGB colors) into color data for each color of the ink used in the inkjet recording apparatus 10.

[0138] The ejection control unit 112 generates an ejection control signal for the printhead drive circuit 128 based on the dot data generated in the image processing unit 110. Further, the ejection control unit 112 includes a drive waveform generation unit (not shown). The drive waveform generation unit is a mechanism for generating a voltage waveform of a drive voltage for driving an ejection energy generation element (in this example, a piezoelectric element) corresponding to each nozzle of the inkjet head 24.

[0139] Drive waveform data is pre-stored in the information storage unit 124 and the used drive waveform data is output as needed. The drive waveform output from the drive waveform generation unit is supplied to the printhead drive circuit 128. Further, the signal output from the drive waveform generation unit may be digital waveform data or an analog voltage signal.

[0140] A common drive voltage is applied to each ejection energy generation element of the inkjet head 24 via the printhead drive circuit 128, and the on and off of a switching element (not shown) connected to the individual electrode of each energy generation element is switched according to the ejection timing of each nozzle, whereby ink is ejected from the corresponding nozzle.

[0141] The information storage unit 124 stores programs executed by the CPU of the control device 102 and various data required for control, etc. The information storage unit 124 stores setting information of the resolution corresponding to the drawing mode, the number of paths (the number of repetitions of scanning), feed amount information required for the control of the conveyance feed amount, control information of the light sources 34A and 34B, etc.

[0142] The number of paths is not particularly limited, preferably 1 path to 32 paths, more preferably 3 paths to 16 paths, and still more preferably 6 paths to 12 paths.

[0143] The encoder 130 is mounted on the drive motors of the scanning drive unit 116 and the conveyance drive unit 114, and outputs a pulse signal corresponding to the rotation amount and rotation speed of the drive motors, 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 grasped.

[0144] The sensor 132 includes various sensors provided in each part of the device. For example, the width of the substrate 12 mounted on the carriage 30 is detected by a sensor, and the width of the substrate 12 is grasped based on the sensor signal obtained from the sensor 132.

[0145] As another example of the sensor 132, 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. can be cited. For example, the control device 102 sends a command signal to a heater control unit (not shown) based on the ink temperature information obtained from the temperature sensor that detects the ink temperature, and the heater control unit controls the operation of the heater based on the command signal from the control device 102.

[0146] <Modification Example>

[0147] The above inkjet recording device 10 is provided with a blower 33, but the inkjet recording device of the present invention may not be provided with a blower. Also, regarding the above inkjet recording device 10, as light sources, light sources 34A and 34B are provided as formal curing light sources for completely curing the ink, but in addition to the formal curing light sources, a pre-curing light source may also be provided. In the case where a pre-curing light source is provided, the pre-curing light source is also preferably mounted on the carriage 30. The pre-curing light source is a mechanism that irradiates active energy rays with an exposure amount smaller than that of the formal curing light source. In the case where a pre-curing light source is provided, exposure is performed in the order of the pre-curing light source and the formal curing light sources (light sources 34A and 34B).

[0148] <Substrate>

[0149] The substrate used in the inkjet recording device of the present invention is not particularly limited, and may be a non-permeable substrate or a permeable substrate, but a non-permeable substrate is preferred.

[0150] Here, the non-permeable substrate refers to a substrate having a water absorption rate (unit: mass%, measurement time: 24 hours) of less than 10 in ASTM D570 of the ASTM test method.

[0151] The above water absorption rate of the non-permeable substrate is preferably 5 mass% or less.

[0152] As non-permeable substrates, for example, mention may be made of paper laminated with plastics (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 metals, plastic films laminated or vapor-deposited with the above metals, leather, etc.).

[0153] As leather, natural leather (also referred to as "genuine leather"), synthetic leather (e.g., PVC (polyvinyl chloride) leather, PU (polyurethane) leather), etc. may be mentioned. Regarding leather, for example, reference may be made to paragraphs 0163 to 0165 of Japanese Patent Laid-Open No. 2009-058750.

[0154] For example, when forming an ink film on leather (e.g., vehicle seats, bags, shoes, wallets, etc.) or a plastic film as a non-permeable substrate, the formed ink film is required to have excellent rub resistance and stretchability.

[0155] Moreover, when forming an ink film on substrates other than leather and plastic films, the formed film may sometimes be required to have excellent rub resistance and stretchability.

[0156] The inkjet recording apparatus according to the present invention can meet such requirements. From this viewpoint, it is more effective to use PVC as the substrate.

[0157] From the viewpoint of improving surface energy, the substrate may also be surface-treated.

[0158] As the surface treatment, corona treatment, plasma treatment, frame treatment, heat treatment, abrasion treatment, light irradiation treatment (UV treatment), etc. may be mentioned, but it is not limited to these.

[0159] The thickness of the substrate is not particularly limited, but from the viewpoint of flexibility, it is preferably 20 μm to 500 μm.

[0160] <Ink>

[0161] The ink used in the inkjet recording device of the present invention contains water and particles containing a polymer P having an acid group and a polymerizable compound A. As described above, the inkjet recording device of the present invention is suitable for an ink containing water and particles containing a polymer P having an acid group and a polymerizable compound A. By using the inkjet recording device of the present invention, the polymerizable compound A sufficiently exudes from the particles contained in the ink, thereby promoting the polymerization of the polymerizable compound A, and excellent in rub resistance and stretchability.

[0162] Hereinafter, the details of each component contained in the ink will be described.

[0163] (Water)

[0164] The ink contains water.

[0165] The content of water relative to the total amount of the ink can be set, for example, to 10% by mass or more and 99% by mass or less.

[0166] The content of water relative to the total amount of the ink is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and particularly preferably 50% by mass or more.

[0167] The upper limit of the content of water relative to the total amount of the ink is appropriately determined according to the content of other components, but is, for example, 99% by mass, preferably 95% by mass, and more preferably 90% by mass.

[0168] <Particles>

[0169] The ink contains at least one kind of particles containing a polymer P and a polymerizable compound A (hereinafter, also referred to as "specific particles").

[0170] 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.

[0171] A preferred mode of the ink is as follows: in the ink before being applied to a substrate, the polymerizable compound A stays in the specific particles, and in the ink applied to the substrate, the polymerizable compound A exudes from the specific particles.

[0172] (Polymerizable Compound A)

[0173] The specific particles contain at least one kind of polymerizable compound A. The polymerizable compound A contained in the specific particles may be only one kind or two or more kinds.

[0174] The polymerizable compound A is not particularly limited as long as it is a compound having a polymerizable group.

[0175] The molecular weight of the polymeric compound A is not particularly limited, but from the viewpoint of improving the stretchability of the image, the weight-average molecular weight is preferably 1000 or more, more preferably 1500 or more, and still more preferably 2000 or more. On the other hand, the upper limit value of the weight-average molecular weight of the polymeric compound A is not particularly limited, but from the viewpoint of dispersion stability, it is preferably 20000 or less, more preferably 15000 or less. The weight-average molecular weight of the polymeric compound A can be set in the range of 1000 to 20000.

[0176] In the present invention, the weight-average molecular weight (Mw) refers to the value measured by gel permeation chromatography (GPC).

[0177] In the measurement based on GPC, as the measurement device, HLC (registered trademark)-8020GPC (Tosoh Corporation) is used. As the column, 3 TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID × 15 cm, Tosoh Corporation) are used. As the eluent, THF (tetrahydrofuran) is used. And, as the measurement conditions, the sample concentration is set to 0.45 mass%, the flow rate is set to 0.35 ml / min, the sample injection volume is set to 10 μL, and the measurement temperature is set to 40 °C, and the measurement is performed using an RI detector.

[0178] The calibration curve is prepared from 8 samples of "standard sample TSK standard, polystyrene" of Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000" and "n-propylbenzene".

[0179] The type of the polymerizable group possessed by the polymeric compound A is not particularly limited, but from the viewpoint of curability, it is more preferably an ethylenically unsaturated group.

[0180] Examples of the ethylenically unsaturated group possessed by the polymeric compound A include (meth)acryloyl group, vinyl group, vinyl ester group and vinyl ether group. From the viewpoint of reactivity, the ethylenically unsaturated group is preferably (meth)acryloyl group or vinyl group, more preferably (meth)acryloyl group. Examples of the (meth)acryloyl group include (meth)acryloyloxy group and (meth)acrylamide group. Among them, from the viewpoint of further improving the rub resistance of the image, the ethylenically unsaturated group is preferably (meth)acryloyl group, more preferably acryloyl group, and still more preferably acryloyloxy group.

[0181] The number of polymerizable groups in the polymerizable compound A may be 1 or 2 or more. However, from the viewpoint of improving the rub resistance of the image, 2 or more are preferred. The upper limit value of the number of polymerizable groups is not particularly limited, and is, for example, 20. From the viewpoint of ease of synthesis, the number of ethylenically unsaturated groups is preferably 2, 3, 6, 9, 10, 15, or 20.

[0182] Furthermore, from the viewpoint of further improving the rub resistance of the image, the polymerizable compound A is preferably a urethane (meth)acrylate having 2 or more (meth)acryloyl groups in 1 molecule.

[0183] Urethane (meth)acrylate refers to a compound having a (meth)acryloyl group and a urethane bond. It is considered that if the polymerizable compound A contains a urethane bond, the adhesion to the substrate is improved, and thus the rub resistance of the image is improved. Also, it is considered that the strength of the ink film is increased by hydrogen bonding between urethane bonds, and as a result, the rub resistance of the image is improved.

[0184] Urethane (meth)acrylate can be produced, for example, by reacting a bifunctional isocyanate compound, a hydroxy group-containing (meth)acrylate, and, if necessary, a polyol.

[0185] Examples of the bifunctional isocyanate compound include aliphatic diisocyanates such as 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-butanediol dipropyl ether diisocyanate, thiodihexyl diisocyanate; aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, dimethylbenzene diisocyanate, ethylbenzene diisocyanate, isopropylbenzene diisocyanate, dimethylbiphenyl diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 2,7-naphthalene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate; and

[0186] alicyclic diisocyanates such as hydrogenated xylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate.

[0187] As the (meth)acrylate containing a hydroxyl group, for example, 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, and pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate can be cited.

[0188] And, as the polymerizable compound A, an acrylate compound, a methacrylate compound, a styrene compound, a vinylnaphthalene compound, an N-vinyl heterocyclic compound, an N-vinylamide, an unsaturated polyester, an unsaturated polyether, an unsaturated polyamide, and an unsaturated urethane can be cited.

[0189] As the acrylate compound, for example, 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, dicyclopentenoxyethyl acrylate, dicyclopentyl acrylate, cyclic trimethylolpropane formaldehyde acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-vinyloxyethoxy)ethyl acrylate, octyl acrylate, decyl acrylate, isodecyl acrylate, lauryl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 4-tert-butylcyclohexyl acrylate, isoamyl acrylate, stearyl acrylate, isostearyl acrylate, 2-ethylhexyl diethylene glycol acrylate, 2-hydroxybutyl acrylate, 2-acryloyloxyethyl hydrogen phthalate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, vinyl ether acrylate, 2-acryloyloxyethyl succinate, 2-acryloyloxyphthalate, 2-acryloyloxyethyl-2-hydroxyethyl phthalate, lactone-modified acrylate, acryloylmorpholine, acrylamide, substituted acrylamide (for example, N-hydroxymethylacrylamide and diacetoneacrylamide), and other monofunctional acrylate compounds;

[0190] 2-functional acrylate compounds such as polyethylene glycol diacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, 1,3-butanediol 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, hydroxyneopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, alkoxylated dimethylol tricyclodecane diacrylate, polytetramethylene glycol diacrylate, alkoxylated cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, dioxane diol diacrylate, cyclohexanedimethanol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), neopentyl glycol propylene oxide adduct diacrylate, etc.;

[0191] Acrylate compounds with 3 or more functional groups such as trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol tetraacrylate, ethoxylated isocyanuric acid triacrylate, ε-caprolactone-modified tris(2-acryloyloxyethyl) isocyanurate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxytetraacrylate, glycerol propoxytriacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, etc.;

[0192] As methacrylate compounds, for example, monofunctional methacrylate compounds such as methyl methacrylate, n-butyl methacrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, dimethylamino methyl methacrylate, methoxypolyethylene glycol methyl acrylate, methoxytriethylene glycol methyl acrylate, 2-hydroxyethyl methacrylate, phenoxyethyl methacrylate, cyclohexyl methacrylate, etc. can be cited;

[0193] 2-functional methacrylate compounds such as polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2-bis(4-methacryloxypolyethoxyphenyl) propane, tetraethylene glycol dimethacrylate, etc.

[0194] As styrene compounds, for example, styrene, p-methylstyrene, p-methoxystyrene, β-methylstyrene, p-methyl-β-methylstyrene, α-methylstyrene, and p-methoxy-β-methylstyrene can be cited.

[0195] As vinylnaphthalene compounds, for example, 1-vinylnaphthalene, methyl-1-vinylnaphthalene, β-methyl-1-vinylnaphthalene, 4-methyl-1-vinylnaphthalene, and 4-methoxy-1-vinylnaphthalene can be cited.

[0196] As N-vinyl heterocyclic compounds, for example, N-vinylcarbazole, N-vinylpyrrolidone, N-vinylethylacetamide, N-vinylpyrrole, N-vinylphenothiazine, N-vinylacetanilide, N-vinylsuccinimide, N-vinylphthalimide, N-vinylcaprolactam, and N-vinylimidazole can be cited.

[0197] As N-vinylamides, for example, allyl glycidyl ether, diallyl phthalate, triallyl trimellitate, and N-vinylformamide can be cited.

[0198] Among them, the radical polymerizable monomer having 2 or less functional groups is preferably at least one selected from 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, diethylene glycol diacrylate, tetraethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate (TPGDA), cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, polyethylene glycol diacrylate, and polypropylene glycol diacrylate.

[0199] And, the radical polymerizable monomer having 3 or more functional groups 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 ethoxytetraacrylate, glycerol propoxytriacrylate, ethoxylated dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, propoxylated glycerol triacrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate.

[0200] As combinations of radically polymerizable monomers having 2 or less functional groups and radically polymerizable monomers having 3 or more functional groups, combinations of a bifunctional acrylate compound and a trifunctional acrylate compound, combinations of a bifunctional acrylate compound and a pentafunctional acrylate compound, and combinations of a monofunctional acrylate compound and a tetrafunctional acrylate compound can be mentioned.

[0201] Moreover, the polymerizable compound A is preferably a polymerizable compound having a cyclic structure, more preferably a bifunctional cyclic (meth)acrylate 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 cyclohexanedimethanol di(meth)acrylate, cyclohexanedimethanol di(meth)acrylate; monofunctional cyclic (meth)acrylates such as (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid tetrahydrofurfuryl ester, (meth)acrylic acid benzyl ester, (meth)acrylic acid isobornyl ester, (meth)acrylic acid dicyclopentenyl ester, (meth)acrylic acid dicyclopentenoxyethyl ester, (meth)acrylic acid dicyclopentyl ester; ethoxylated isocyanuric acid tri(meth)acrylate or ε-caprolactone-modified tris(2-(meth)acryloyloxyethyl) isocyanurate,

[0202] More preferably, it is the above-mentioned bifunctional cyclic (meth)acrylate, dicyclopentenyl acrylate, dicyclopentenoxyethyl acrylate or dicyclopentyl acrylate, and particularly preferably the above-mentioned bifunctional cyclic (meth)acrylate.

[0203] In addition to the above, commercially available products described in "Crosslinking Agent Handbook" edited by Shinzo Yamashita (TAISEISHA, 1981); "UV·EB Curing Handbook (Raw Material Edition)" edited by Kiyomi Kato (Polymer Publishing Society, 1985); "Application and Market of UV·EB Curing Technology" edited by RadTech Japan, page 79 (CMC Publishing Co., Ltd., 1989); "Polyester Resin Handbook" written by Eiichiro Ryuzan (NIKKAN KOGYO SHIMBUN, LTD., 1988), etc. and radically polymerizable compounds well-known in the industry can also be used.

[0204] In addition, the photopolymerizable monomers used in the photopolymerizable compositions described in each of the gazettes such as Japanese Patent Laid-Open No. 7-159983, Japanese Patent Publication No. 7-31399, Japanese Patent Laid-Open No. 8-224982, Japanese Patent Laid-Open No. 10-863, Japanese Patent Laid-Open No. 9-134011, and Japanese Patent Publication No. 2004-514014 can also be applied as the polymerizable compound A that can be included in the specific particles.

[0205] The polymerizable compound A may be a commercially available product on the market.

[0206] Examples of commercially available products include AH-600 (bifunctional), AT-600 (bifunctional), UA-306H (hexafunctional), UA-306T (hexafunctional), UA-306I (hexafunctional), UA-510H (decafunctional), UF-8001G (bifunctional), DAUA-167 (bifunctional), LIGHT ACRYLATE NPA (bifunctional), LIGHT ACRYLATE 3EG-A (bifunctional) (above, KYOEISHACHEMICAL 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), SR499 (trifunctional), CD501 (trifunctional), SR502 (trifunctional), SR9020 (trifunctional), CD9021 (trifunctional), SR9035 (trifunctional), SR494 (tetrafunctional), SR399E (pentafunctional) (above, Sartomer Company, Inc.), A-NOD-N (NDDA, bifunctional), A-DOD-N (DDDA, bifunctional), A-200 (bifunctional), APG-400 (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) (above, SHIN-NAKAMURA CHEMICAL Co., Ltd.), UV-7510B (trifunctional) (Nippon Synthetic Chemical Industry Co., Ltd.), KAYARAD DPCA-30 (hexafunctional) and KAYARAD DPEA-12 (hexafunctional) (above, Nippon Kayaku Co., Ltd.).

[0207] Moreover, as examples of commercially available products, NPGPODA (neopentyl glycol propylene oxide adduct diacrylate), SR531, SR285, SR256 (above, Sartomer Company, Inc.), A-DHP (dipentaerythritol hexaacrylate, SHIN-NAKAMURA CHEMICAL Co., Ltd.), ARONIX (registered trademark) M-156 (TOAGOSEI CO., LTD.), V-CAP (BASF Corporation), VISCOAT #192 (Osaka Organic Chemical Industry Co., Ltd.) can be cited.

[0208] Among them, SR506, SR833S, A-9300 or A-9300-CL as polymerizable monomers having a cyclic structure are particularly preferred, and SR833S is more preferred.

[0209] In the ink, the content of the polymerizable compound A is preferably 1% by mass to 15% by mass, more preferably 2% by mass to 8% by mass, relative to the total amount of the ink.

[0210] (Polymer P having an acid group)

[0211] The specific particles contain at least one polymer P having an acid group (hereinafter, also simply referred to as "polymer P").

[0212] Polymer P plays a role of retaining the polymerizable compound A in the specific particles in the ink before being applied to the substrate, thereby contributing to improving the storage stability of the ink.

[0213] Polymer P can be a linear polymer or a crosslinked polymer.

[0214] In the present invention, a linear polymer means a polymer having no crosslinked structure, and a crosslinked polymer means a polymer having a crosslinked structure.

[0215] The linear polymer can have a cyclic structure or a branched structure.

[0216] Regarding the specific particles containing the linear polymer, i.e., polymer P, reference can be made to, for example, Japanese Patent No. 6584677.

[0217] As a preferred form of the specific particles when polymer P is a crosslinked polymer, microcapsules containing a shell formed of the crosslinked polymer, i.e., polymer P, and a core containing a polymerizable compound can be cited.

[0218] Regarding the specific particles containing the crosslinked polymer, i.e., polymer P, reference can be made to, for example, Japanese Patent No. 6510681.

[0219] - Weight-average molecular weight (Mw)-

[0220] The weight-average molecular weight (Mw) of polymer P is preferably from 3,000 to 200,000, more preferably from 4,000 to 150,000, still more preferably from 5,000 to 100,000, still more preferably from 8,000 to 80,000, and still more preferably from 10,000 to 50,000.

[0221] When the Mw of polymer P is 3,000 or more, the storage stability of the ink is further improved. The reason is considered to be that when the Mw of polymer P is 3,000 or more, the function of polymer P (the function of retaining polymerizable compound A in specific particles, in other words, the function of suppressing the leakage of polymerizable compound A from specific particles) in the ink before being applied to the substrate is more effectively exerted.

[0222] When the Mw of polymer P is 200,000 or less, the anti-blocking property of the image is further improved. The reason is considered to be that when the Mw of polymer P is 200,000 or less, the decrease in fluidity (i.e., thickening) of the ink applied to the substrate during the drying process is suppressed, and as a result, the volatilization of the liquid components (i.e., water and water-soluble organic solvents) from the ink is further promoted.

[0223] - Glass transition temperature (Tg)-

[0224] The glass transition temperature (Tg) of polymer P is not particularly limited.

[0225] From the viewpoint of improving the mobility of polymer P and further improving the image quality (specifically, suppressing the roughness of the image), the Tg of polymer P is preferably 120°C or lower, more preferably 100°C or lower, still more preferably 80°C or lower, and still more preferably 70°C or lower.

[0226] On the other hand, the Tg of polymer P is preferably 0°C or higher, more preferably 10°C or higher, still more preferably 20°C or higher, and still more preferably 30°C or higher.

[0227] In the present invention, the glass transition temperature (Tg) of the polymer refers to the value measured using a differential scanning calorimeter (DSC).

[0228] The specific measurement of the glass transition temperature is carried out according to the method described in JIS K 7121 (1987) or JIS K 6240 (2011).

[0229] The glass transition temperature in the present invention is the extrapolated glass transition start temperature (hereinafter, sometimes referred to as Tig).

[0230] A method for measuring the glass transition temperature will be described in more detail.

[0231] When determining the glass transition temperature, maintain at a temperature about 50 °C lower than the expected glass transition temperature of the resin until the apparatus stabilizes, and then heat at a heating rate of 20 °C / minute until a temperature about 30 °C higher than the temperature at which the glass transition ends, to produce a differential thermal analysis (DTA) curve or a DSC curve.

[0232] The extrapolated glass transition start temperature (Tig), which is the glass transition temperature in the present invention, is determined as the temperature of the intersection of a straight line extending the low-temperature side baseline in the DTA curve or DSC curve to the high-temperature side and a tangent line drawn from the point where the gradient of the curve in the stepped change portion of the glass transition becomes maximum.

[0233] When the ink contains two or more polymers P, the glass transition temperature (Tg) of the polymer P refers to the weighted average of the glass transition temperatures of the respective polymers P.

[0234] Examples of the polymer P include urethane polymers, urethane-urea polymers, urea polymers, acrylic polymers, polyesters, polyolefins, polystyrenes, polycarbonates, polyamides, and the like.

[0235] Here, the urethane polymer refers to a polymer containing a urethane bond and not containing a urea bond, the urea polymer refers to a polymer containing a urea bond and not containing a urethane bond, and the urethane-urea polymer refers to a polymer containing a urethane bond and a urea bond.

[0236] Furthermore, the acrylic polymer refers to a polymer (homopolymer or copolymer) containing at least one raw material monomer selected from the group consisting of acrylic acid, derivatives of acrylic acid (e.g., acrylates, etc.), methacrylic acid, and derivatives of methacrylic acid (e.g., methacrylates, etc.).

[0237] -bond U-

[0238] The polymer P preferably contains at least one of a urethane bond and a urea bond, i.e., bond U. In other words, the polymer P is preferably a urethane polymer, a urethane-urea polymer, or a urea polymer.

[0239] When the polymer P contains bond U, in the ink deposited on the substrate, specific particles are more likely to interact with each other through the interaction of bond U (e.g., hydrogen bond). Therefore, it is easier to carry out the linking of specific particles caused by the polymerization of the polymerizable compound A exuded from the specific particles. As a result, it is easier to carry out the curing between specific particles, and thus the rub resistance of the image is further improved.

[0240] Bond U preferably contains a urethane bond.

[0241] In other words, the polymer P preferably contains urethane bonds and does not contain urea bonds, or contains both urethane bonds and urea bonds.

[0242] -acid group-

[0243] The polymer P preferably contains at least one kind of acid group.

[0244] Thereby, it contributes to the dispersion stability of specific particles in the ink, and as a result, the storage stability of the ink is further improved.

[0245] The acid group may or may not be neutralized.

[0246] Examples of the non-neutralized acid group include carboxyl group, sulfo group, sulfate group, phosphonic acid group, phosphoric acid group, etc.

[0247] The neutralized acid group refers to the acid group in the form of "salt" (for example, the salt of carboxyl group (such as -COONa)). Examples of the neutralized acid group include salts of carboxyl group, sulfo group, sulfate group, phosphonic acid group, phosphoric acid group, etc.

[0248] Neutralization can be carried out, for example, using alkali metal hydroxides (such as sodium hydroxide, potassium hydroxide, etc.) or organic amines (such as triethylamine, etc.).

[0249] As the acid group in the polymer P, from the viewpoint of further improving the storage stability of the ink, it is preferably at least one selected from the group consisting of carboxyl group, salt of carboxyl group, sulfo group, salt of sulfo group, sulfate group, salt of sulfate group, phosphonic acid group, salt of phosphonic acid group, phosphoric acid group and salt of phosphoric acid group, and more preferably at least one selected from the group consisting of carboxyl group, salt of carboxyl group, sulfo group and salt of sulfo group.

[0250] As the "salt" in the above-mentioned salts of carboxyl group, sulfo group, sulfate group, phosphonic acid group and phosphoric acid group, an alkali metal salt or an organic amine salt is preferred, and an organic amine salt is more preferred.

[0251] As the organic amine in the organic amine salt, N,N-diisopropylethylamine or triethylamine is preferred.

[0252] Moreover, when the total millimoles of the acid groups (such as carboxyl group and salt of carboxyl group) contained in 1 g of the polymer P is defined as the acid value of the polymer P, from the viewpoint of dispersion stability, the acid value of the 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.

[0253] Moreover, the degree of neutralization of the acid group in the polymer P is preferably 50% to 100%, and more preferably 70% to 100%.

[0254] Here, the degree of neutralization refers to the ratio of "the number of neutralized acid groups" in polymer P to "the total of the number of unneutralized acid groups (such as carboxyl groups) and the number of neutralized acid groups (such as salts of carboxyl groups)" (i.e., the ratio [the number of neutralized acid groups / (the number of unneutralized acid groups + the number of neutralized acid groups)]).

[0255] The degree of neutralization of the acid groups in polymer P can be measured by neutralization titration.

[0256] - Polymerizable group -

[0257] The specific particles contain not only polymer P but also polymerizable compound A. Therefore, polymer P does not necessarily need to contain polymerizable groups. However, from the viewpoint of further improving the rub resistance of the image, polymer P can also contain polymerizable groups.

[0258] As the polymerizable groups that can be contained in polymer P, photopolymerizable groups or thermopolymerizable groups are preferred.

[0259] As the photopolymerizable groups, radical polymerizable groups are preferred, more preferably groups containing an olefinic double bond, and still more preferably (meth)acryloyl, allyl, styryl or vinyl. As the radical polymerizable groups, from the viewpoints of radical polymerization reactivity and the hardness of the formed film, (meth)acryloyl is particularly preferred.

[0260] As the thermopolymerizable groups, epoxy groups, oxetanyl groups, aziridinyl groups, azetidinyl groups, keto groups, aldehyde groups or blocked isocyanate groups are preferred.

[0261] Polymer P can contain only one kind of polymerizable group or can contain two or more kinds.

[0262] That polymer P contains polymerizable groups can be confirmed, for example, by Fourier transform infrared spectroscopy (FT-IR) analysis.

[0263] When the millimole number of the olefinic double bond in 1 g of polymer P is defined as the C═C valence of polymer P, from the viewpoint of further improving the hardness of the image, the C═C valence of polymer P is preferably 0.05 mmol or more, more preferably 0.10 mmol / g or more, still more preferably 0.30 mmol / g or more, and particularly preferably 0.50 mmol / g or more.

[0264] From the viewpoint of further improving the water resistance and alcohol resistance of the image, the C═C valence of the polymer P is preferably 0.05 mmol or more, more preferably 0.10 mmol / g or more, still 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.

[0265] On the other hand, from the viewpoint of improving the curing property of the ink over time (i.e., suppressing the decrease in the curing property of the ink over time), the C═C valence of the polymer P is preferably 4.00 mmol / g or less, more preferably 3.00 mmol / g or less, still more preferably 2.00 mmol / g or less, and particularly preferably 1.50 mmol / g or less.

[0266] The polymer P may also contain other structures in addition to the above structures (i.e., the bond U, the hydrophilic group, and the polymerizable group).

[0267] Examples of the other structures include a polysiloxane bond (i.e., a divalent polysiloxanyl group), a monovalent polysiloxanyl group, a monovalent fluorinated hydrocarbon group, and a divalent fluorinated hydrocarbon group.

[0268] -Preferred Structure of Polymer P-

[0269] 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.

[0270] The polymer P in the above preferred embodiment contains a bond U formed by the reaction between the isocyanate group of the isocyanate compound and the active hydrogen group of the compound containing an active hydrogen group.

[0271] As the active hydrogen group, a hydroxyl group, a primary amino group, or a secondary amino group is preferred.

[0272] For example, by the reaction between an isocyanate group and a hydroxyl group, a urethane group is formed.

[0273] And, by the reaction between an isocyanate group and a primary amino group or a secondary amino group, a urea group is formed.

[0274] Hereinafter, the isocyanate compound and the compound containing an active hydrogen group that are raw materials for the polymer P having the above preferred structure may sometimes be referred to as raw material compounds.

[0275] The isocyanate compound as the raw material compound may be only one kind or two or more kinds.

[0276] The compound containing an active hydrogen group as the raw material compound may be only one kind or two or more kinds.

[0277] At least one of the isocyanate compounds as raw material compounds, preferably an isocyanate compound having two or more functional groups.

[0278] At least one of the compounds containing an active hydrogen group as raw material compounds, preferably a compound containing two or more active hydrogen groups.

[0279] 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. Thus, it is easy to manufacture the polymer P containing a hydrophilic group. In this case, at least a part of the hydrophilic groups in the finally obtained polymer P may be groups in which the hydrophilic groups in the raw material compounds are neutralized.

[0280] A more preferred mode is as follows: at least one of the compounds containing an active hydrogen group in the raw material compounds is a compound containing an active hydrogen group and a hydrophilic group.

[0281] When the polymer P contains a polymerizable group, among the raw material compounds, at least one of the isocyanate compound and the compound containing an active hydrogen group preferably contains a polymerizable group. Thus, it is easy to manufacture the polymer P containing a polymerizable group.

[0282] A more preferred mode is as follows: at least one of the compounds containing an active hydrogen group in the raw material compounds is a compound containing an active hydrogen group and a polymerizable group.

[0283] As described above, the polymer P can be a linear polymer or a crosslinked polymer.

[0284] The linear polymer as the polymer P can be manufactured by reacting a bifunctional isocyanate compound with a compound containing two active hydrogen groups.

[0285] The crosslinked polymer as the polymer P can be manufactured by reacting a trifunctional or higher functional isocyanate compound with a compound containing two or more active hydrogen groups.

[0286] The crosslinked polymer as the polymer P can also be manufactured by reacting a bifunctional isocyanate compound with a compound containing three or more active hydrogen groups.

[0287] Hereinafter, preferred raw material compounds will be described.

[0288] -Isocyanate compound-

[0289] As the isocyanate compound, a bifunctional or higher functional isocyanate compound is preferred, and a bifunctional to hexafunctional isocyanate compound is more preferred.

[0290] When a bifunctional isocyanate compound is used as a raw material compound, the polymer P contains a structural unit derived from the bifunctional isocyanate compound, namely the following structural unit (P1).

[0291] [Chemical formula 1]

[0292]

[0293] In the structural unit (P1), L 1 represents a divalent organic group having 1 to 20 carbon atoms, and * represents the bonding position.

[0294] As specific examples of L 1 can be cited residues obtained by removing two isocyanate groups (NCO groups) from the bifunctional isocyanate compounds involved in the following specific examples.

[0295] Specific examples of the bifunctional isocyanate compound are as follows. Among them, the bifunctional isocyanate compound is not limited to the following specific examples.

[0296] [Chemical formula 2]

[0297]

[0298] Furthermore, as the bifunctional isocyanate compound, a bifunctional isocyanate compound derived from the above specific examples can also be used. For example, Duranate (registered trademark) D101, D201, A101 (manufactured by Asahi Kasei Corporation), etc. can be cited.

[0299] Furthermore, the polyfunctional isocyanate compound having 3 or more functional groups is preferably a reaction product of at least one selected from the group including bifunctional isocyanate compounds and at least one selected from the group including compounds having 3 or more active hydrogen groups (for example, polyol compounds having 3 or more functional groups, polyamine compounds having 3 or more functional groups, and polythiol compounds having 3 or more functional groups).

[0300] The molar number (number of molecules) of the bifunctional isocyanate compound reacting with the compound having 3 or more active hydrogen groups relative to the molar number (equivalent number of active hydrogen groups) of the active hydrogen groups in the compound having 3 or more active hydrogen groups is preferably 0.6 times or more, more preferably 0.6 to 5 times, further preferably 0.6 to 3 times, and still further preferably 0.8 to 2 times.

[0301] As the bifunctional isocyanate compound used for forming the polyfunctional isocyanate compound having 3 or more functional groups, the bifunctional isocyanate compounds involved in the above specific examples can be cited.

[0302] As the compound containing 3 or more active hydrogen groups for forming an isocyanate compound having 3 or more functional groups, the compounds described in paragraphs 0057 to 0058 of WO2016 / 052053 can be cited.

[0303] As the isocyanate compound having 3 or more functional groups, an adduct type isocyanate compound having 3 or more functional groups, an isocyanurate type isocyanate compound having 3 or more functional groups, a biuret type isocyanate compound having 3 or more functional groups, etc. can be cited.

[0304] As commercially available products of the adduct type isocyanate compound having 3 or more functional groups, Takenate (registered trademark) D-102, D-103, D-103H, D-103M2, P49-75S, D-110N, D-120N, D-140N, D-160N (above, Mitsui Chemicals, Inc.), Desmodule (registered trademark) L75, UL57SP (Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HL, HX, L (Nippon Polyurethane Industry Co., Ltd.), P301-75E (Asahi Kasei Corporation), etc. can be cited.

[0305] As commercially available products of the isocyanurate type isocyanate compound having 3 or more functional groups, Takenate (registered trademark) D-127N, D-170N, D-170HN, D-172N, D-177N (above, Mitsui Chemicals, Inc.), SUMIDUR N3300, Desmodule (registered trademark) N3600, N3900, Z4470BA (above, Sumika Bayer Urethane Co., Ltd.), CORONATE (registered trademark) HX, HK (above, Nippon Polyurethane Industry Co., Ltd.), Duranate (registered trademark) TPA-100, TKA-100, TSA-100, TSS-100, TLA-100, TSE-100 (above, Asahi Kasei Corporation), etc. can be cited.

[0306] Examples of commercially available polyfunctional isocyanate compounds having a biuret structure and having three or more functional groups include Takenate (registered trademark) D-165N, NP1100 (both from Mitsui Chemicals, Inc.), Desmodule (registered trademark) N3200 (Sumika Bayer Urethane Co., Ltd.), Duranate (registered trademark) 24A-100 (Asahi Kasei Corporation), and the like.

[0307] At least one of the isocyanate compounds as the raw material compound may be an isocyanate compound containing a hydrophilic group. For the isocyanate compound containing a hydrophilic group, reference can be made to paragraphs 0112 to 0118 and paragraphs 0252 to 0254 of International Publication No. 2016 / 052053.

[0308] At least one of the isocyanate compounds as the raw material compound may be an isocyanate compound containing a polymerizable group. For the isocyanate compound containing a polymerizable group, reference can be made to paragraphs 0084 to 0089, paragraph 0203, and paragraph 0205 of International Publication No. 2016 / 052053.

[0309] -Compound Containing Active Hydrogen Group-

[0310] As the compound containing an active hydrogen group, a compound containing two or more active hydrogen groups is preferred.

[0311] As the compound containing two or more active hydrogen groups, a polyol compound (i.e., a compound having two or more hydroxyl groups) or a polyamine compound (i.e., a compound having two or more amino groups) is more preferred.

[0312] When a compound containing an active hydrogen group and a hydrophilic group is used as the raw material compound, the polymer P preferably contains at least one of the following structural units (P0).

[0313] [Chemical Formula 3]

[0314]

[0315] In the structural unit (P0),

[0316] L 0 represents a divalent organic group,

[0317] Y 1 and Y 2 each independently represents an oxygen atom, a sulfur atom, or -NR 1 -group,

[0318] R 1represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms,

[0319] * indicates the bonding position.

[0320] In the structural unit (P0), L 0 The divalent organic group represented by may be a group containing carbon atoms and hydrogen atoms, or a group containing carbon atoms, hydrogen atoms and heteroatoms (for example, oxygen atoms, nitrogen atoms, sulfur atoms, etc.).

[0321] L 0 The divalent organic group represented by may contain at least one of a hydrophilic group and a polymerizable group.

[0322] As L 0 Specific examples thereof include residues obtained by removing two active hydrogen groups from the specific examples of the compounds containing two or more active hydrogen groups described later.

[0323] As R 1 , it 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.

[0324] Y 1 and Y 2 are each independently preferably an oxygen atom or a -NR 1 - group, more preferably an oxygen atom.

[0325] Specific examples of the diol compound as the compound containing an active hydrogen group are shown below, but the compound containing an active hydrogen group is not limited to the following specific examples.

[0326] [Chemical formula 4]

[0327]

[0328] In compounds (12) to (15), nC 7 H 15 , nC 9 H 19 , nC 11 H 23 and nC 17 H 35 represent n-heptyl, n-nonyl, n-undecyl and n-heptadecyl, respectively.

[0329] In compound (16), PPG is polypropylene glycol and n is the number of repetitions.

[0330] In compound (16-2), PEG is polyethylene glycol and n is the number of repetitions.

[0331] The compound (17) PEs is a polyester diol, n is the number of repetitions, and Ra and two Rbs are each independently a divalent hydrocarbon group having 2 to 25 carbon atoms. The n Ras in the compound (17) PEs may be the same or different. The (n + 1) Rbs in the compound (17) PEs may be the same or different.

[0332] The compound (18) PCD is a polycarbonate diol, n is the number of repetitions, and (n + 1) Rcs are each independently an alkylene group having 2 to 12 carbon atoms (preferably 3 to 8, more preferably 3 to 6). The (n + 1) Rcs in the compound (18) PCD may be the same or different.

[0333] The compound (19) PCL is a polycaprolactone diol, n and m are each the number of repetitions, and Rd is an alkylene group having 2 to 25 carbon atoms.

[0334] -Compound containing an active hydrogen group and a polymerizable group-

[0335] As the compound containing an active hydrogen group, a compound containing an active hydrogen group and a polymerizable group can also be cited.

[0336] The compound containing an active hydrogen group and a polymerizable group is suitable as a compound for introducing a polymerizable group into the polymer P (hereinafter, also referred to as "compound for introducing a polymerizable group").

[0337] The following shows specific examples of diol compounds as the compound containing an active hydrogen group and a polymerizable group, but the compound containing an active hydrogen group and a polymerizable group is not limited to the following specific examples.

[0338] [Chemical formula 5]

[0339]

[0340] Regarding the compound containing an active hydrogen group and a polymerizable group, reference can be appropriately made to the description in paragraphs 0075 to 0089 of International Publication No. 2016 / 052053.

[0341] -Compound containing an active hydrogen group and a hydrophilic group-

[0342] As the compound containing an active hydrogen group, a compound containing an active hydrogen group and a hydrophilic group can also be cited.

[0343] The compound containing an active hydrogen group and a hydrophilic group is suitable as a compound for introducing a hydrophilic group into the polymer P (hereinafter, also referred to as "compound for introducing a hydrophilic group").

[0344] When using the compound containing an active hydrogen group and a hydrophilic group as a raw material compound, the polymer P preferably contains the following structural unit (P2).

[0345] [Chemical formula 6]

[0346]

[0347] In the structural unit (P2),

[0348] L 21 represents a trivalent organic group having 1 to 20 carbon atoms,

[0349] L 22 represents a single bond or a divalent organic group having 1 to 20 carbon atoms,

[0350] A 1 represents a carboxyl group, a salt of a carboxyl group, a sulfo group or a salt of a sulfo group,

[0351] * represents the bonding position.

[0352] L 21 The number of carbon atoms in the trivalent organic group having 1 to 20 carbon atoms represented by is preferably 2 to 20, more preferably 3 to 20, and still more preferably 4 to 20.

[0353] As L 21 The trivalent organic group represented preferably includes a trivalent hydrocarbon group or a group in which at least one carbon atom in the trivalent hydrocarbon group is replaced by a heteroatom (preferably an oxygen atom, a sulfur atom or a nitrogen atom).

[0354] L 22 The number of carbon atoms in the divalent organic group having 1 to 20 carbon atoms represented by is preferably 1 to 10, more preferably 1 to 6.

[0355] As L 22 The divalent organic group represented preferably includes a divalent hydrocarbon group (preferably an alkylene group) or a group in which at least one carbon atom in the divalent hydrocarbon group (preferably an alkylene group) is replaced by an oxygen atom or a sulfur atom (preferably an oxygen atom).

[0356] L 22 may be a single bond.

[0357] Specific examples of the compound containing an active hydrogen group and a hydrophilic group are shown below, but the compound containing an active hydrogen group and a hydrophilic group is not limited to the following specific examples. The carboxyl group and the sulfo group in the following specific examples may be neutralized respectively (that is, they may be a salt of a carboxyl group and a salt of a sulfo group).

[0358] [Chemical formula 7]

[0359]

[0360] Regarding the compound containing an active hydrogen group and a hydrophilic group, reference can be appropriately made to paragraphs 0112 to 0118 and paragraphs 0252 to 0254 of International Publication No. 2016 / 052053.

[0361] The content of polymer P is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 80% by mass, still more preferably 30% by mass to 70% by mass, and still more preferably 40% by mass to 60% by mass with respect to the total solid content of the specific particles.

[0362] In the present invention, the total solid content of the specific particles means the total amount of the solvent (i.e., water and organic solvents) removed from the specific particles. 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.

[0363] The content of polymer P is preferably 0.3% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, and still more preferably 1% by mass to 10% by mass with respect to the total amount of the ink.

[0364] From the viewpoint of the 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, more preferably 0.4 to 0.6. When the ratio is within the above range, the function of the polymer P (the function of retaining the polymerizable compound A in the specific particles, in other words, the function of suppressing the exudation of the polymerizable compound A from the specific particles) is more effectively exerted.

[0365] (Free radical polymerization initiator)

[0366] The specific particles preferably contain at least one free radical polymerization initiator.

[0367] In the present invention, the free radical polymerization initiator means a compound that generates free radicals by absorbing light.

[0368] When the specific particles contain a free radical polymerization initiator, the abrasion resistance and adhesion of the ink film are further improved.

[0369] It is considered that the reason is that the distance between the polymerizable compound A and the free radical polymerization initiator becomes closer, and the curing sensitivity of the ink film (hereinafter, also simply referred to as "sensitivity") is improved.

[0370] Further, in the case where the specific particles contain a radical polymerization initiator, a radical polymerization initiator that has high sensitivity in the past but has been difficult to use due to low dispersibility or low solubility in water (for example, a radical polymerization initiator having a solubility in water of 1.0 mass% or less at 25°C) can be used. As a result, the selection range of the radical polymerization initiator to be used is expanded, and further, the selection range of the light source to be used is also expanded. Therefore, the curing sensitivity can be improved as compared with the past.

[0371] Specific examples of the radical polymerization initiator that has high sensitivity in the past but has been difficult to use due to low dispersibility or low solubility in water include the carbonyl compounds and acylphosphine oxide compounds described below, and acylphosphine oxide compounds are preferred.

[0372] By including a radical polymerization initiator having low solubility in water in specific particles, the radical polymerization initiator can be included in the ink.

[0373] In addition, the storage stability of the ink in which the specific particles contain a radical polymerization initiator is also excellent as compared with conventional photocurable compositions. It is considered that this is because the aggregation or precipitation of the radical polymerization initiator can be suppressed by including the radical polymerization initiator in the specific particles.

[0374] As the radical polymerization initiator, for example, reference can be appropriately made to the descriptions in paragraphs 0091 to 0094 of International Publication No. 2016 / 052053.

[0375] As the radical polymerization initiator, 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 (for example, product name "Omnirad 819", manufactured by IGM Resins B.V.), 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (for example, product name "Omnirad 369", manufactured by IGM Resins B.V.), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (for example, product name "Omnirad 907", manufactured by IGM Resins B.V.), 1-hydroxy-cyclohexyl-phenyl-ketone (product name "Omnirad 184", manufactured by IGM Resins B.V.), 2,4,6-trimethylbenzoyl-diphenyl-oxide phosphine (for example, product name "Omnirad TPO-H", manufactured by IGM Resins B.V.), (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (for example, product name "Omnirad TPO-L", manufactured by IGM Resins B.V.).

[0376] Among them, from the viewpoints of improving sensitivity and adaptability to LED light, etc., as the radical polymerization initiator, (b) acylphosphine oxide compounds are preferred, and monoacylphosphine oxide compounds or bisacylphosphine oxide compounds are more preferred.

[0377] As the wavelength of the LED light, 355 nm, 365 nm, 385 nm, 395 nm or 405 nm is preferred.

[0378] Specific particles in the form containing a polymerization initiator can be produced, for example, by emulsifying a mixture of an oil phase component and an aqueous phase component in which a polymer P (or a raw material compound for producing polymer P), a polymerizable compound A and a polymerization initiator are mixed.

[0379] 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 still more preferably 1% by mass to 6% by mass with respect to the total solid content of the specific particles.

[0380] 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 still more preferably 0.5% by mass to 1.5% by mass with respect to the total amount of the ink.

[0381] (Sensitizer)

[0382] The specific particles preferably contain at least one kind of sensitizer.

[0383] When the specific particles contain a photopolymerization initiator, the specific particles preferably contain a sensitizer.

[0384] If the specific particles contain a sensitizer, the decomposition of the photopolymerization initiator caused by the irradiation with active energy rays can be further promoted.

[0385] A sensitizer is a substance that absorbs specific active energy rays and becomes an electronically excited state. The sensitizer in the electronically excited state comes into contact with the photopolymerization initiator to produce effects such as electron transfer, energy transfer, and heat generation. Thereby, the chemical change of the photopolymerization initiator, that is, the decomposition, generation of free radicals, acids or bases, etc. are promoted.

[0386] Examples of the sensitizer include benzophenone, thioxanthone, isopropylthioxanthone, anthraquinone, 3-acylcoumarin derivatives, terphenyl, styryl ketone, 3-(aroyl methylene)thiazoline, camphorquinone, eosin, rhodamine, erythrosine, etc.

[0387] Further, as the sensitizer, it is also preferable to use a compound represented by the general formula (i) described in Japanese Patent Application Laid-Open No. 2010-24276, a compound represented by the general formula (I) described in Japanese Patent Application Laid-Open No. 6-107718, and the like.

[0388] Among them, as the sensitizer, from the viewpoints of adaptability to LED light and reactivity with the photoinitiator, at least one selected from thioxanthone, isopropylthioxanthone, and benzophenone is preferable, at least one selected from thioxanthone and isopropylthioxanthone is more preferable, and isopropylthioxanthone is further preferable.

[0389] 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 further preferably 0.3% by mass to 10% by mass relative to the solid content of the specific particles.

[0390] 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 further preferably 0.1% by mass to 0.2% by mass relative to the total amount of the ink.

[0391] The specific particles containing a photoinitiator and a sensitizer can be produced, for example, by emulsifying a mixture obtained by mixing an oil phase component and an aqueous phase component containing a polymer P (or a raw material compound for producing the polymer P), a polymerizable compound A, a photoinitiator, and a sensitizer.

[0392] (Other components)

[0393] The specific particles may further contain other components in addition to the above components.

[0394] As the other components, for example, compounds containing at least one selected from the group consisting of a polysiloxane bond (i.e., a divalent polysiloxanyl group), a monovalent polysiloxanyl group, a monovalent fluorinated hydrocarbon group, and a divalent fluorinated hydrocarbon group can be mentioned.

[0395] (Method for producing an aqueous dispersion of specific particles)

[0396] The ink of the present invention can produce an aqueous dispersion of specific particles containing the above specific particles and water, and if necessary, other components can be added to the obtained aqueous dispersion for production.

[0397] Furthermore, since the ink of the present invention is a form of an aqueous dispersion of specific particles, depending on the composition of the ink, the ink can also be directly produced (i.e., without adding other components) as an aqueous dispersion of specific particles.

[0398] The method for producing the aqueous dispersion of specific particles is not particularly limited.

[0399] As methods for producing an aqueous dispersion of specific particles, the following production methods A and B can be cited.

[0400] - Production method A-

[0401] Production method A has the following steps: An aqueous dispersion of specific particles is obtained by mixing an oil phase component containing an organic solvent, polymer P, and a polymerizable monomer and an aqueous phase component containing water and emulsifying them.

[0402] 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.

[0403] Regarding production method A, publicly known documents such as Japanese Patent No. 6584677 can be referred to.

[0404] - Production method B-

[0405] Production method B has the following steps: An aqueous dispersion of specific particles is obtained by mixing an oil phase component containing an organic solvent, a raw material compound of polymer P (for example, a polyfunctional isocyanate compound having three or more functional groups, a compound having two or more active hydrogen groups, etc.), and a polymerizable monomer and an aqueous phase component containing water and emulsifying them.

[0406] Production method B is suitable as a method for producing an aqueous dispersion of specific particles (for example, microcapsules) containing polymer P in the form of a crosslinked polymer.

[0407] Regarding production method B, publicly known documents such as International Publication No. 2016 / 052053 can be referred to.

[0408] <Organic solvent>

[0409] The ink preferably contains at least one organic solvent (preferably a water-soluble organic solvent).

[0410] Thereby, the ejectability of the ink from the inkjet head is further ensured.

[0411] In the present invention, "water-soluble" in "water-soluble organic solvent" means the property of dissolving 1 g or more in 100 g of water at 25°C.

[0412] The amount of the water-soluble organic solvent dissolved in 100 g of water at 25°C is preferably 5 g or more, more preferably 10 g or more.

[0413] The content of the water-soluble organic solvent relative to the total amount of the ink is preferably 1% by mass to 35% by mass, more preferably 3% by mass to 30% by mass, further preferably 5% by mass to 20% by mass, and further preferably 7% by mass to 15% by mass.

[0414] When the content of the water-soluble organic solvent is 1% by mass or more, the ejection property of the ink is further improved.

[0415] When the content of the water-soluble organic solvent is 35% by mass or less, the storage stability of the ink is further improved.

[0416] Specific examples of the water-soluble organic solvent are as follows.

[0417] · Alcohols (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.)

[0418] · Polyhydric alcohols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, 2-methyl-1,3-propanediol, etc.)

[0419] · 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.)

[0420] · Amines (e.g., ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.)

[0421] · Amides (e.g., formamide, N,N-dimethylformamide, N,N-dimethylacetamide, etc.)

[0422] · Heterocycles (e.g., 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, etc.)

[0423] · Sulfoxides (e.g., dimethyl sulfoxide, etc.)

[0424] · Sulfones (e.g., sulfolane, etc.)

[0425] · Others (urea, acetonitrile, acetone, etc.)

[0426] <Colorant>

[0427] The ink can be an ink containing at least one colorant (so-called "colored ink") or an ink not containing a colorant (so-called "transparent ink").

[0428] When the ink contains a coloring agent, it is preferable that the coloring agent is contained outside the specific particles (i.e., the specific particles do not contain the coloring agent).

[0429] As the coloring agent, there is no particular limitation, and it can be arbitrarily selected and used from known coloring agents such as pigments, water-soluble dyes, and disperse dyes. Among them, from the viewpoints of excellent weather resistance and rich color reproducibility, the coloring agent is more preferably a pigment.

[0430] As the pigment, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, known organic pigments and inorganic pigments can be cited. Also, as the pigment, 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. with the pigment as the dispersion medium and pigments whose surfaces have been treated with resins, pigment derivatives, etc.) can be cited.

[0431] As the organic pigment and inorganic pigment, for example, yellow pigment, red pigment, magenta pigment, blue pigment, cyan pigment, green pigment, orange pigment, purple pigment, brown pigment, black pigment, white pigment, etc. can be cited.

[0432] When using a pigment as the coloring agent, a pigment dispersant can be used as needed.

[0433] Also, when using a pigment as the coloring agent, as the pigment, a self-dispersing pigment having a hydrophilic group on the surface of the pigment particles can be used.

[0434] Regarding the coloring agent and the pigment dispersant, paragraphs 0180 to 0200 of Japanese Patent Laid-Open No. 2014-040529 and paragraphs 0122 to 0129 of International Publication No. 2016 / 052053 can be appropriately referred to.

[0435] When the ink contains a coloring agent, the content of the coloring agent relative to the total amount of the ink 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.

[0436] <Other Components>

[0437] The ink can contain other components in addition to those described above as needed.

[0438] The other components can be contained in the specific particles or can be not contained in the specific particles.

[0439] The ink can contain a surfactant, a polymerization inhibitor, an ultraviolet absorber, etc. as other components.

[0440] Further, the ink may contain a water-soluble polymerizable monomer, a water-soluble photoinitiator, a water-soluble resin, etc. on the outside of the specific particles as needed.

[0441] Regarding these components, for example, reference can be made to paragraphs 0134 to 0157 of International Publication No. 2016 / 052053.

[0442] (Preferred method for manufacturing ink)

[0443] The method for manufacturing the ink is not particularly limited, and a method preferably including the following steps is preferred: a step of manufacturing an aqueous dispersion of specific particles by the above-described method for manufacturing an aqueous dispersion (Production Method A or Production Method B); and

[0444] a step of adding other components such as a pigment and a water-soluble organic solvent to the aqueous dispersion of specific particles and mixing them.

[0445] Further, as another mode of the method for manufacturing the ink, a mode of directly manufacturing the ink as an aqueous dispersion of specific particles (that is, a method of not adding other components to the aqueous dispersion of specific particles) by the above-described method for manufacturing an aqueous dispersion (Production Method A or Production Method B) can also be cited.

[0446] (Preferred physical properties of ink)

[0447] The viscosity of the ink at 25°C is preferably 3 mPa·s to 15 mPa·s, more preferably 3 mPa·s to 13 mPa·s. If the viscosity of the ink is within the above range, higher ejection stability can be achieved.

[0448] In addition, the viscosity of the ink is a value measured using a viscometer.

[0449] As the viscometer, for example, VISCOMETER TV-22 (Toki Sangyo Co., Ltd.) can be used.

[0450] [Inkjet recording method]

[0451] The inkjet recording method of the present invention preferably includes: a step of heating the surface of the substrate on the side opposite to the surface where the ink lands using the inkjet recording apparatus of the present invention and the above-described ink (hereinafter, also referred to as "heating step"); a step of ejecting the ink onto the substrate (hereinafter, also referred to as "ejecting step"); and a step of irradiating the surface of the substrate where the ink lands with active energy rays (hereinafter, also referred to as "irradiating step").

[0452] Hereinafter, the operation of irradiating active energy rays is sometimes referred to as "exposure".

[0453] In the inkjet recording method of the present invention, since the inkjet recording apparatus of the present invention is used, the same effects as those obtained by the inkjet recording apparatus of the present invention can be exhibited.

[0454] The ink used in the inkjet recording method of the present invention is the same as the ink used in the inkjet recording apparatus of the present invention, and thus the description thereof is omitted.

[0455] In the inkjet recording method of the present invention, the ink preferably contains an organic solvent.

[0456] Preferably, the content of water in the ink landed on the substrate at the time of irradiating the active energy ray is 5% by mass or less with respect to the content of water at the time of landing on the substrate, and the content of the organic solvent in the ink landed on the substrate at the time of irradiating the active energy ray is 30% by mass or more with respect to the content of the organic solvent at the time of landing on the substrate.

[0457] In other words, at the time of irradiating the active energy ray, it is preferably in a state where almost no water remains in the ink at the time of landing on the substrate, and a certain amount of the organic solvent preferably remains. When the residual states of water and the organic solvent are in the above states, the exudation of the polymerizable compound A from the specific particles is promoted, and the subsequent polymerization reaction is easily carried out, further improving the image quality, rub resistance, and stretchability of the obtained image.

[0458] Hereinafter, the ratio of the content of water at the time of irradiating the active energy ray to the content of water at the time of landing on the substrate is defined as the "residual ratio of water", and the ratio of the content of the organic solvent at the time of irradiating the active energy ray to the content of the organic solvent at the time of landing on the substrate is defined as the "residual ratio of the organic solvent" for explanation.

[0459] The lower limit value of the residual ratio of water is not particularly limited and may be 0% by mass.

[0460] The upper limit value of the residual ratio of the organic solvent is preferably 80% by mass.

[0461] The residual ratio of water and the residual ratio of the organic solvent are calculated by the following method.

[0462] At the time of irradiating the active energy ray, the inkjet recording apparatus is stopped, and a measurement sample of 25 mm × 30 mm is cut out.

[0463] - Residual ratio of water -

[0464] Using a trace moisture measurement device (product name "CA-200", manufactured by Mitsubishi Chemical Analytech Co., Ltd.), the water content B1 (mg / m 2)。The water vaporization temperature is set at 140°C. For the anolyte, a coulometric titration reagent (product name: “AQUAMICRON AKX”, manufactured by Mitsubishi Chemical Corporation) is used, and for the catholyte, a coulometric titration reagent (product name: “AQUAMICRON CxU”, manufactured by Mitsubishi Chemical Corporation) is used.

[0465] In addition, the water content B2 (mg / m 2 ) of the substrate before inkjet recording is measured in the same manner as the water content B1.

[0466] “B1 - B2” refers to the mass per unit area (mg / m 2 ) of water in the ink deposited on the substrate at the time of irradiation with actinic energy rays.

[0467] Moreover, the content of the 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).

[0468] Based on the ink filled in the ink cartridge, the ratio of the content of the polymerizable compound A to the water content is calculated. Using the mass per unit area of the polymerizable compound A contained in the measurement sample and the above ratio, the mass per unit area A (mg / m 2 ) of water in the ink deposited on the substrate at the time of ink deposition is calculated. The residual ratio of water is calculated according to the following formula.

[0469] Residual ratio of water (mass %) = {(B1 - B2) / A} × 100

[0470] - Residual ratio of organic solvent -

[0471] From the surface where the ink from the measurement sample is deposited, 1 mL of methanol is used to extract the organic solvent contained in the ink deposited on the substrate at 25°C for 24 hours. Using the obtained extract, the mass per unit area C (mg / m 2 ) of the organic solvent in the ink deposited on the substrate at the time of irradiation with actinic energy rays is measured by a gas chromatograph (product name: “GC - 2010”, manufactured by Shimadzu Corporation).

[0472] Moreover, the content of the polymerizable compound A contained in the measurement sample was measured using a high-performance liquid chromatograph (product name: "Prominence" (liquid delivery unit: LC-20AT, detector: SPD-M20A), manufactured by Shimadzu Corporation).

[0473] Based on the ink filled in the ink cartridge or ink bottle, the ratio of the content of the polymerizable compound A to the content of the organic solvent was calculated. Using the mass per unit area of the polymerizable compound A contained in the measurement sample and the above ratio, the mass D (mg / m 2 ) of the organic solvent per unit area in the ink landed on the substrate at the time of ink landing was calculated. The residual ratio of the organic solvent was calculated according to the following formula.

[0474] Residual ratio of organic solvent (mass %) = (C / D) × 100

[0475] <Heating process>

[0476] The heating process is a process of heating the surface on the opposite side of the substrate from the surface where the ink lands. For example, through a platen disposed below the substrate, the surface on the opposite side of the substrate from the surface where the ink lands is heated.

[0477] The substrate can be pre-heated before the ink lands, can be heated at the time of ink landing, can be heated after the ink lands, or can be any combination thereof.

[0478] From the viewpoint of promoting the exudation of the polymerizable compound A, it is preferable that the substrate is pre-heated before the ink lands, and it is more preferable that the substrate is pre-heated before the ink lands and is also heated at the time of ink landing.

[0479] The heating temperature is preferably 35°C to 60°C, and more preferably 40°C to 50°C.

[0480] <Jetting process>

[0481] The jetting process is a process of jetting the above ink onto the substrate.

[0482] The ink is jetted by an inkjet recording method using the inkjet recording apparatus of the present invention.

[0483] As the resolution of the inkjet head, it is preferably 300 dpi or more, more preferably 600 dpi or more, and further preferably 800 dpi or more.

[0484] Here, dpi (dot per inch) means the number of dots per 2.54 cm (1 inch).

[0485] The droplet ejection amount of the ink ejected from the inkjet head (the droplet ejection amount per dot) is preferably from 1 pL (picoliter) to 100 pL, more preferably from 3 pL to 80 pL, and still more preferably from 3 pL to 50 pL.

[0486] The inkjet recording method of the present invention preferably includes a blowing step of blowing a gas onto the ejected ink after the ejection step. By blowing the gas, the drying of the ink is further performed, and the image quality and rub resistance of the image are further improved.

[0487] The temperature of the gas to be blown is, for example, from 20°C to 60°C.

[0488] The blowing of the gas onto the applied ink can be performed, for example, using a blower provided in the inkjet recording apparatus of the present invention.

[0489] <Irradiation step>

[0490] 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).

[0491] By the irradiation of the active energy rays (i.e., exposure) in this step, the polymerizable compound A in the ink polymerizes and the ink cures, thereby obtaining an image. More specifically, as described above, after the ink has landed, the polymerizable compound A effectively oozes out from the specific particles, whereby the curing between the specific particles (i.e., the connection between the specific particles) is sufficiently performed, and as a result, an image excellent in image quality and rub resistance can be obtained.

[0492] The irradiation of the active energy rays on the ink ejected onto the substrate can be performed in a state where the substrate and the ink ejected onto the substrate are heated. And the irradiation of the active energy rays on the ink ejected onto the substrate can be performed in a state where the substrate and the ink ejected onto the substrate are heated and a gas is blown onto the ink ejected onto the substrate by a blower.

[0493] The irradiation energy of the active energy rays (i.e., the exposure amount) is preferably 20 mJ / cm 2 or more, more preferably 100 mJ / cm 2 or more, and still more preferably 500 mJ / cm 2 or more.

[0494] The upper limit value of the exposure amount is not particularly limited and can be 5 J / cm 2 , or can be 1,500 mJ / cm 2 .

[0495] And the irradiation step may include a step of pre-curing the ink with a relatively small exposure amount and a step of formally curing the ink with a relatively large exposure amount. The exposure amount when pre-curing the ink is preferably 50 mJ / cm2 ~500 mJ / cm 2 ,more preferably 100 mJ / cm 2 ~300 mJ / cm 2 。

[0496] Examples

[0497] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

[0498] Unless otherwise specified, "room temperature" means 25°C.

[0499] <Preparation of Polymer P>

[0500] 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 "EBECRYL600", manufactured by DAICEL-ALLNEX LTD.), 28.8 g of 2,2-bis(hydroxymethyl)propionic acid, a hydroxyl group-containing silicone compound (product name "SILAPLANE FM-DA11", manufactured by JNC Corporation) 25.3 g and 0.01 g of 2-tert-butyl-1,4-benzoquinone were charged into a 1-liter three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, heated to 70°C, and 0.5 g of bismuth tris(2-ethylhexanoate) (product name "NEOSTANN U-600", manufactured by DAICEL-ALLNEX LTD.) was added. Then, while maintaining the temperature inside the reaction vessel at 70°C, it was stirred for 8 hours.

[0501] Next, a solution containing 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. Then, 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, it was stirred for 1 hour to obtain a polymer P solution (content of polymer P: 40% by mass).

[0502] [Example 1]

[0503] <Preparation of Aqueous Dispersion of Specific Particles>

[0504] - Preparation of Oil Phase Component -

[0505] The following components were mixed and stirred at room temperature for 30 minutes to obtain an oil phase component.

[0506] 40% by mass solution of polymer P... 38.7 g

[0507] Polymeric 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 DPHA... 15.5 g

[0508] Polymerization initiator: (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (product name "Omnirad TPO-L", manufactured by IGM Resins B.V.)... 2.5 g

[0509] Sensitizer: isopropylthioxanthone (ITX)... 0.6 g

[0510] Ethyl acetate... 31.7 g

[0511] Methyl ethyl ketone... 9.4 g

[0512] - Preparation of aqueous dispersion of specific particles -

[0513] The above oil phase components and 84.6 g of distilled water were mixed, and the resulting mixture was emulsified at 7000 rpm for 30 minutes at room temperature using a homogenizer to obtain an emulsion.

[0514] 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, whereby ethyl acetate and methyl ethyl ketone were distilled off from the above liquid.

[0515] The liquid from which ethyl acetate and methyl ethyl ketone were distilled off was diluted with distilled water so that the solid component concentration became 25% by mass, thereby obtaining an aqueous dispersion of specific particles (content of specific particles: 25% by mass).

[0516] The volume average dispersion particle size of the specific particles is 100 nm.

[0517] <Preparation of ink>

[0518] Each component was mixed to prepare an ink.

[0519] · The above aqueous dispersion of specific particles (content of specific particles 25% by mass)... 44 parts by mass

[0520] · Pigment dispersion: Product name "Pro-jet Black APD4000", manufactured by FUJIFILM Imaging Colorants, Inc., pigment concentration 15% by mass, concentration of pigment dispersant 6% by mass... 20 parts by mass

[0521] · Surfactant: Product name "EMULGEN 707", manufactured by Kao Corporation, solid component concentration 100% by mass... 1.0 part by mass

[0522] · Surfactant: Product name "SURFYNOL 440", manufactured by Evonik Japan Co., Ltd., solid component concentration 100% by mass... 1.0 part by mass

[0523] · Surfactant: Product name "TEGO Wet 270", manufactured by Evonik Japan Co., Ltd., solid component concentration 100% by mass... 1.0 part by mass

[0524] · Water... the balance to make the total ink 100 parts by mass

[0525] 〔Examples 2 to 15, Comparative Examples 1 to 2〕

[0526] The aqueous dispersion of specific particles was prepared by the same method as in Example 1 such that the content of each component contained in the ink became those shown in Tables 1 and 2, and the ink was obtained by the same method as in Example 1.

[0527] <Image Recording>

[0528] An Figure 1 inkjet recording apparatus of the multipath method (i.e., shuttle scanning method) shown was prepared. Figure 6 The distance X1 shown was adjusted to the values shown in Tables 1 and 2. Conveyor rollers for conveying the substrate were provided, and pressing plates 26A, 26B, and 26C shown in Figure 2 were provided below the conveyor rollers. The inkjet head used was the inkjet head described in Figure 3. In Examples 4 to 15 and Comparative Examples 1 to 2, a blower 33A was provided above the inkjet head. The blower 33A was arranged at a certain angle so that the wind with a wind speed of 1.0 m / s flowed toward the outlet side in the conveying direction.

[0529] The scanning speed of the inkjet head was set to 1000 mm / second, and the scanning distance per scan of the inkjet head was set to 1700 mm.

[0530] The above ink was filled in the ink cartridge attached to the inkjet recording apparatus, and an image was recorded on the substrate by the following method.

[0531] As the substrate, a PVC (polyvinyl chloride) film (product name "LAG Jet P-282ZW", thickness 80 μm, manufactured by LINTEC Corporation) was used.

[0532] The temperature of the pressing plate 26A in Figure 2 was set to the heating temperature described in Tables 1 and 2.

[0533] The heated substrate is conveyed, and the ink is ejected from the inkjet head of the above-described inkjet recording apparatus onto the heated substrate. The ejection conditions of the ink are set to 900 dpi (dots per inch), 10 pL per dot, 8 paths, and bidirectional printing.

[0534] The temperature of the platen 26B in FIG. 2 is set to the heating temperatures described in Tables 1 and 2, and the ink is ejected while heating the substrate, and the ink is ejected while blowing gas from the blower provided above the inkjet head.

[0535] The substrate on which the ink has landed is exposed using the light sources 34A and 34B so that the exposure amount becomes 1000 mJ / cm 2 to obtain an image recording material. The substrate is exposed while being heated, and the substrate is exposed while blowing gas from the blower.

[0536] In addition, in Examples 1 to 3, since the blower was not provided, gas was not blown during the ejection and exposure of the ink.

[0537] Using the obtained image recording material, evaluations of image quality, rub resistance, and stretchability were performed. In addition, the ejection property during image recording was evaluated. The evaluation methods are as follows.

[0538] <Image Quality>

[0539] Using the above-described ink stored at room temperature within 1 day after preparation, character images shown in Figure 8 were recorded in each of the sizes of 5 dots, 6 dots, and 7 dots under the above-described image recording conditions.

[0540] Each size of character image was observed using a 10-fold process magnifying glass (manufactured by ETSUMI Co., Ltd.). Based on the observed results, the fineness of the image was evaluated according to the following evaluation criteria. The evaluation criteria are as follows. A, B, and C are levels that are practically acceptable.

[0541] A: The character image shown in Figure 8 for the 5-dot size is formed without being flattened or bleeding.

[0542] B: The character image shown in Figure 8 for the 6-dot size is formed without being flattened or bleeding (however, except when it meets A).

[0543] C: The character image shown in Figure 8 for the 7-dot size is formed without being flattened or bleeding (however, except when it meets A and B).

[0544] D: For the 7-dot sizeFigure 8 The character image shown is formed by being flattened or bleeding

[0545] <Scratch resistance>

[0546] By the above image recording method, a solid image of a rectangle of 100 mm × 30 mm was recorded on a substrate with a recording duty ratio of 100%, thereby obtaining an image recording object. The obtained image recording object was placed in an environment of 25°C and a relative humidity of 50% for 24 hours.

[0547] A cotton cloth (Kanakin #3) was placed on the image recording surface of the image recording object after placement, and using a Gakushin type friction tester (manufactured by TESTER SANGYO CO., LTD.), a load of 200 g was applied and reciprocally rubbed 100 times. The image recording surface after rubbing was observed with the naked eye to confirm the rubbing marks and the peeling state of the image. The evaluation criteria are as follows. Evaluations 3, 4, and 5 are at a level where there are no practical problems.

[0548] 5: There are no rubbing marks in the image.

[0549] 4: There are rubbing marks in the image, but they do not reach the substrate.

[0550] 3: There are rubbing marks in the image, a part of the rubbing marks reaches the substrate, but the visible area of the substrate exceeds 0% and is less than 5% of the area of the image at the initial recording (30 cm 2 ).

[0551] 2: There are rubbing marks in the image, a part of the rubbing marks reaches the substrate, and the visible area of the substrate is 5% or more and less than 50% of the area of the image at the initial recording (30 cm 2 ).

[0552] 1: There are rubbing marks in the image, a part of the rubbing marks reaches the substrate, and the visible area of the substrate is 50% or more of the area of the image at the initial recording (30 cm 2 ).

[0553] <Tensile property>

[0554] By the above image recording method, a solid image of a rectangle of 100 mm × 30 mm was recorded on a substrate with a recording duty ratio of 100%, thereby obtaining an image recording object. The obtained image recording object was placed in an environment of 25°C and a relative humidity of 50% for 24 hours.

[0555] The image density of the image recording object after placement (i.e., the image recording object before stretching) was measured using a fluorescence spectrophotometer (product name "FD-7", manufactured by KONICA MINOLTA JAPAN, INC.).

[0556] Using a tensile testing machine (product name "Autograph AG-IS 5kN type", manufactured by SHIMADZU CORPORATION), the placed image recording material was set with the distance between the clamps being 5 cm, and stretched at a tensile speed of 300 mm / minute until the distance between the clamps became 13 cm.

[0557] The image density of the stretched image recording material was measured in the same manner as that of the image recording material before stretching. Also, the stretched image recording material was visually observed to confirm the presence or absence of cracks. Based on the change in the image density of the stretched image recording material and that of the image recording material before stretching, as well as the presence or absence of cracks, the stretchability was evaluated. The evaluation criteria are as follows. Evaluations 3, 4, and 5 are at levels where there are no practical problems.

[0558] Change in image density before and after stretching = Image density of the image recording material before stretching - Image density of the stretched image recording material

[0559] 5: No cracks in the image were seen after stretching, and the change in the image density before and after stretching was less than 0.5. 4: No cracks in the image were seen after stretching, and the change in the image density before and after stretching was 0.5 or more and less than 0.8.

[0560] 3: No cracks in the image were seen after stretching, and the change in the image density before and after stretching was 0.8 or more and less than 1.1.

[0561] 2: No cracks in the image were seen after stretching, but the change in the image density before and after stretching was 1.1 or more.

[0562] 1: Cracks in the image were seen after stretching.

[0563] <Ejectability>

[0564] The above ink stored at room temperature within 1 day after preparation was ejected from the inkjet head of the above inkjet recording device for 30 minutes, and then the ejection was stopped.

[0565] After 5 minutes had passed since the ejection was stopped, the above ink was ejected again from the above inkjet head onto the substrate, and a solid image of 5 cm × 5 cm was recorded.

[0566] The obtained image was visually observed to confirm the presence or absence of dot missing caused by non-ejecting nozzles, and the ejectability of the ink was evaluated according to the following evaluation criteria. The evaluation criteria are as follows. Evaluations A and B are at levels where there are no practical problems.

[0567] A: No dot missing caused by non-ejecting nozzles was confirmed, and a good image was obtained.

[0568] B: Slight occurrence of dot missing due to the occurrence of non-jetting nozzles, etc. was confirmed, but it was at a level that was not problematic in practical use.

[0569] C: Occurrence of dot missing due to the occurrence of non-jetting nozzles, and an image that is problematic in practical use.

[0570] The evaluation results are shown in Table 1 and Table 2. In Table 1 and Table 2, as Figure 6 shown, the distance X1 refers to the distance in the conveyance direction between the end on the downstream side in the conveyance direction of the nozzle 70 and the end on the upstream side in the conveyance direction of the light sources 34A and 34B. "Polymerizable compound A / (polymer P + polymerizable compound A)" refers to the mass ratio of the content of the polymerizable compound A to the total content of the polymer P and the polymerizable compound A. "Residual ratio of water" refers to the ratio of the water content at the time of irradiating active energy rays to the water content at the time of landing on the substrate. "Residual ratio of organic solvent" refers to the ratio of the organic solvent content at the time of irradiating active energy rays to the organic solvent content at the time of landing on the substrate. The calculation methods for the residual ratio of water and the residual ratio of organic solvent are as described above.

[0571] [Table 1]

[0572]

[0573] [Table 2]

[0574]

[0575] As shown in Table 1 and Table 2, it can be seen that in Examples 1 to 15, since the distance X1 in the inkjet recording apparatus is 10 mm to 200 mm, the image quality, rub resistance, and stretchability of the obtained images are excellent.

[0576] On the other hand, it can be seen that in Comparative Example 1, since the distance X1 is less than 10 mm, the image quality, rub resistance, and stretchability are poor.

[0577] It can be seen that in Comparative Example 2, since the distance X1 exceeds 200 mm, the rub resistance and stretchability are poor.

[0578] It can be seen that in Examples 5 and 13, the distance X1 is 40 mm to 150 mm, and compared with Example 12, the rub resistance and stretchability are excellent.

[0579] It can be seen that in Example 7, the heating temperature is 35°C to 60°C, and compared with Examples 10 and 11, the image quality, rub resistance, and stretchability are excellent.

[0580] In addition, the entire disclosure of Japanese Patent Application No. 2022-175010, filed on October 31, 2022, is incorporated herein by reference in its entirety. Further, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and separately indicated to be incorporated by reference.

Claims

1. An inkjet recording apparatus comprising: an inkjet head having nozzles 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 mechanism for scanning the inkjet head in a scanning direction; a conveying mechanism for conveying the substrate in a conveying direction intersecting the scanning direction; a heating mechanism for heating a side of the substrate opposite to the surface on which the ink lands; and a light source for irradiating an active energy ray onto the surface of the substrate where the ink lands after the ink ejected from the nozzles lands on the substrate, wherein a distance in the conveying direction between an end portion on the downstream side in the conveying direction of the nozzle and an end portion on the upstream side in the conveying direction of the light source is 10 mm to 200 mm.

2. The inkjet recording apparatus according to claim 1, wherein the distance is 40 mm to 150 mm.

3. The inkjet recording apparatus according to claim 1, wherein the heating mechanism performs heating at a temperature of 35°C to 60°C.

4. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus further comprises a blower for spraying a gas onto the surface of the substrate where the ink lands.

5. An inkjet recording method using the inkjet recording apparatus and the ink according to any one of claims 1 to 4, the inkjet recording method comprising: a step of heating a side of the substrate opposite to the surface on which the ink lands; a step of ejecting the ink onto the substrate; and a step of irradiating the active energy ray onto the surface of the substrate where the ink lands.

6. The inkjet recording method according to claim 5, wherein the ink further contains an organic solvent, a content of water in the ink landing on the substrate at the time of irradiating the active energy ray is 5% by mass or less relative to a content of water in the ink at the time when the ink lands on the substrate, and a content of the organic solvent in the ink landing on the substrate at the time of irradiating the active energy ray is 30% by mass or more relative to a content of the organic solvent in the ink at the time when the ink lands on the substrate.

7. The inkjet recording method according to claim 5, wherein a 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.

Images