Inkjet recording method and inkjet recording device

Abstract

To provide an inkjet recording method which can effectively suppress accumulation of a dye in a flow channel part of an inkjet recording device, and can effectively suppress deviation of a hue in a recording part formed on a recording medium from a target hue.SOLUTION: An inkjet recording method includes an image formation step of imparting a discharged ink composition onto a recording medium using an inkjet recording device including an ink composition, an ink storage part, a recording head and a flow channel part for circulating the ink composition, and forming an image. The ink composition contains a coloring material containing at least one selected from the group consisting of C.I. acid red 407, C.I. acid blue 140, C.I. acid blue 161 and C.I. acid brown 298, and water. At least a part of the flow channel part is an elastomer-made tube having surface roughness Ra of its inner surface of 10 μm or less, and an inner diameter of 5 mm or more.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Inkjet recording methods and recording devices are not limited to home printers, but are widely used in a variety of industrial and commercial applications.

[0003] In an inkjet recording device that uses a large amount of ink over its lifetime, coloring material may accumulate in the ink composition flow path, causing partial or complete blockage of the flow path. Even a partial blockage of the flow path can cause problems such as insufficient flow rate of the ink composition, leading to printing defects and deviation from the target color.

[0004] As a recording method for suppressing color unevenness and improving image quality, a method has been proposed in which an ink containing a specific dye such as CI Acid Red 407 together with a nitrogen-containing heterocyclic compound is used (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-26963 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, when recording is performed by the inkjet method over a long period of time, it is not possible to sufficiently suppress the accumulation of dye in the flow path of the inkjet recording device, and it is not possible to sufficiently suppress deviations from the target color in the recorded matter. [Means for solving the problem]

[0007] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0008] An inkjet recording method according to an application example of the present invention includes an inkjet recording apparatus including an ink composition, an ink reservoir portion for storing the ink composition, a recording head for ejecting the ink composition, and a flow path portion for distributing the ink composition from the ink reservoir portion to the recording head, the inkjet recording method including an image forming step of applying the ink composition ejected from the recording head to a recording medium to form an image, the ink composition contains water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298; At least a part of the flow path is an elastomer tube, The surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, The elastomer tube has an inner diameter of 5 mm or more.

[0009] An inkjet recording apparatus according to an application example of the present invention includes an ink composition, an ink storage section in which the ink composition is stored, a recording head that ejects the ink composition, and a flow path section that distributes the ink composition from the ink storage section to the recording head, the ink composition contains water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298; At least a part of the flow path is an elastomer tube, The surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, The elastomer tube has an inner diameter of 5 mm or more. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic diagram for explaining a method for measuring the air permeability of a tube. [Diagram 2] FIG. 2 is a perspective view that shows a schematic configuration of an example of an inkjet recording apparatus in a see-through state. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the arrangement of the degassing unit. [Figure 4] FIG. 4 is a schematic diagram showing another example of the arrangement of the deaeration section. [Diagram 5] FIG. 5 is a schematic diagram showing an example of the deaeration unit. [Figure 6] FIG. 6 is a table showing the configuration of the inkjet recording device and the evaluation results for Examples 1 to 13. [Figure 7] FIG. 7 is a table showing the configuration of the inkjet recording apparatus and the evaluation results for Examples 14 to 26. [Figure 8] FIG. 8 is a table showing the configuration of the inkjet recording apparatus and the evaluation results for Examples 27 to 39. [Figure 9] FIG. 9 is a table showing the configuration of the inkjet recording apparatus and the evaluation results for Examples 40 to 52. [Figure 10] FIG. 10 is a table showing the configuration of the inkjet recording apparatus and the evaluation results for Examples 53 to 65. [Figure 11] FIG. 11 is a table showing the configurations of the inkjet recording apparatus and the evaluation results for Examples 66 to 67 and Comparative Examples 1 to 9. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments of the present invention will now be described in detail. [1] Inkjet recording method

[0012] First, the ink jet recording method of the present invention will be described. The inkjet recording method of the present invention includes an image forming step of forming an image by applying the ink composition ejected from the recording head to a recording medium using an inkjet recording device including an ink composition, an ink storage section in which the ink composition is stored, a recording head for ejecting the ink composition, and a flow path section for distributing the ink composition from the ink storage section to the recording head. The ink composition contains water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298. At least a part of the flow path section is an elastomer tube, the surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, and the inner diameter of the elastomer tube is 5 mm or more.

[0013] This makes it possible to provide an inkjet recording method that can effectively prevent the deposition of dye in the flow path of the inkjet recording device, and can effectively prevent the color of the recording part formed on the recording medium from deviating from the target color. In addition, the use of an elastomer tube makes it easy to assemble the inkjet recording device, which is also advantageous for miniaturizing the inkjet recording device.

[0014] As described above, the deposition of the dye in the flow passage of the inkjet recording device can be effectively suppressed, and the color of the recording portion formed on the recording medium can be effectively suppressed from deviating from the target color. It is believed that the following reasons are the reason why CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298 are all characterized by a planar chemical structure and a relatively large molecular weight. Therefore, even in an elastomer tube where minute gaps are likely to occur, the specific dye is unlikely to enter such gaps and is unlikely to deposit. Furthermore, since the surface roughness Ra of the inner surface of the elastomer tube is a predetermined value or less and the inner diameter is a predetermined value or more, the deposition of the specific dye on the inner surface of the elastomer tube is effectively suppressed. This is believed to be because the surface roughness Ra is a predetermined value or less, the dye is unlikely to adhere to the tube surface, and the inner diameter is a predetermined value or more, the effect of water evaporation is relatively small. It is believed that the effects of these configurations work synergistically to obtain the above-mentioned excellent effects.

[0015] On the other hand, if the above conditions are not met, satisfactory results will not be obtained. For example, if an ink composition is used that does not contain at least one colorant selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298, and that contains only colorant components other than these, accumulation of the colorant is likely to occur in the flow path of the inkjet recording device, and the color in the recording portion formed on the recording medium is likely to deviate from the target color.

[0016] Furthermore, if the surface roughness Ra of the inner surface of the elastomer tube is too large or the inner diameter of the elastomer tube is too small, the color material is likely to accumulate in the flow path of the inkjet recording device, and the color of the recording part formed on the recording medium is likely to deviate from the target color.

[0017] [1-1] Image forming process The image forming process is a process in which an ink composition is ejected from a recording head provided in an inkjet recording apparatus and applied to a recording medium to form an image.

[0018] [1-1-1] Recording medium The recording medium to which the ink composition is applied will be described below.

[0019] The recording medium may be any material to which the ink composition can be attached, and examples of the recording medium include various types of paper such as plain paper, recycled paper, and paper specifically for inkjet printing, various types of fabrics, plastic sheets, metal sheets, and composites of these, etc. The recording medium may also be a three-dimensional object other than a sheet.

[0020] Among them, the recording medium is preferably a fabric, which is preferable because it has good dyeability with CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, or CI Acid Brown 298 and can provide good color development.

[0021] The fabric as a recording medium will be described below. Fabrics are fabrics made by shaping fibers into knitted fabrics, woven fabrics, nonwoven fabrics, and the like.

[0022] Examples of woven fabrics include plain weave, twill weave, satin weave, varied plain weave, varied twill weave, varied satin weave, variegated weave, patterned weave, single layer weave, double weave, multi-layer weave, warp pile weave, weft pile weave, and leno weave.

[0023] The fabric may be processed into clothing and other accessories, etc. Examples of clothing and other accessories include sewn T-shirts, handkerchiefs, scarves, towels, carrier bags, cloth bags, curtains, sheets, bed covers, wallpaper, and other furniture items.

[0024] Examples of fibers constituting the fabric include natural fibers such as cotton, hemp, wool, silk, leather, and wood; synthetic fibers such as polypropylene, polyester, acetate, triacetate, polyamide, acrylic, and polyurethane; and biodegradable fibers such as polylactic acid, and may be blended fibers using two or more of these. In particular, animal fibers such as wool and silk, and polyamide are preferred in that they have good dyeability with CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298, and good color development can be obtained.

[0025] The fabric preferably has a basis weight of, for example, 1.0 oz or more and 10.0 oz or less. This allows better recording on the fabric.

[0026] [1-1-2] Overview of the overall configuration of the inkjet recording device Next, the overall configuration of the inkjet recording device used in the inkjet recording method of the present invention will be outlined. Details of the inkjet recording device, particularly the configuration other than the ink composition and the elastomer tube, will be described in detail in [2] below.

[0027] The inkjet recording device includes an ink storage section in which the ink composition is stored, a recording head that ejects the ink composition, and a flow path section that distributes the ink composition from the ink storage section to the recording head.

[0028] [1-1-2-1] Ink composition In the present invention, an ink composition containing water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298 is used.

[0029] In the present invention, a plurality of types of ink compositions may be used. This makes it possible, for example, to widen the color gamut that can be expressed.

[0030] When a plurality of types of ink compositions are used, at least one of the ink compositions may contain water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298. However, it is preferable that the plurality of ink compositions contain water and a colorant including at least one selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298.

[0031] [1-1-2-1-1] Coloring materials In the present invention, an ink composition is used that contains at least one colorant selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298. In the following description, CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298 are referred to as "specific dyes."

[0032] The content of the colorant in the ink composition used in the present invention is preferably from 1.0% by mass to 15.0% by mass, more preferably from 2.0% by mass to 12.0% by mass, and even more preferably from 3.0% by mass to 9.0% by mass.

[0033] This makes it easier to ensure sufficient color density in the recording portion formed using the ink composition. Furthermore, in the past, when the ink composition contained the coloring material at such a content, the above-mentioned problems were particularly likely to occur, but in the present invention, even when the content of the coloring material in the ink composition is within the above range, the occurrence of the above-mentioned problems can be effectively suppressed. In other words, when the content of the coloring material in the ink composition is within the above range, the effects of the present invention are more pronounced.

[0034] The ink composition used in the present invention may further contain coloring material components other than the specific dyes, in addition to the specific dyes. In the following description, coloring material components other than the specific dyes are referred to as "other coloring material components". Examples of other coloring material components include various dyes and pigments other than those mentioned above.

[0035] However, the proportion of other coloring material components in the total coloring materials contained in the ink composition is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0036] [1-1-2-1-2]Water The ink composition containing the specific dye described above contains water. Water is the main component that imparts fluidity to the ink composition.

[0037] Water is a component that mostly evaporates and dissipates after the ink composition is applied to a recording medium.

[0038] Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, and ultrapure water from which ionic impurities have been removed as much as possible. Water that has been sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like is preferred because it can inhibit the growth of mold and bacteria when the ink composition is stored for a long period of time.

[0039] The water content in the ink composition is preferably from 50.0% to 90.0% by mass, more preferably from 60.0% to 85.0% by mass, and even more preferably from 70.0% to 83.0% by mass.

[0040] [1-1-2-1-3] glycol ether The ink composition may further contain a glycol ether.

[0041] This improves the solubility of the specific dye in the ink composition, more effectively suppresses the deposition of the dye in the flow path of the inkjet recording device, and more effectively suppresses the color of the recording part formed on the recording medium from deviating from the target color. In addition, the glycol ether can function as a humectant and a penetrating solvent, so that the ink composition can have better penetrability into the recording medium and better ejection stability by the inkjet method.

[0042] Examples of glycol ethers include glycol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monobutyl ether, and methyl triglycol; diethylene glycol, triethylene glycol, and dipropylene glycol. One or more selected from these may be used in combination.

[0043] Among these, the glycol ether is preferably triethylene glycol or triethylene glycol monobutyl ether. This makes the above-mentioned effects more pronounced.

[0044] The content of glycol ether in the ink composition is preferably 3.0% by mass or more, more preferably from 3.5% to 12.0% by mass, and even more preferably from 4.0% to 11.0% by mass. This makes the above-mentioned effects more pronounced.

[0045] [1-1-2-1-4]1-(2-hydroxyethyl)pyrrolidin-2-one The ink composition may further contain 1-(2-hydroxyethyl)pyrrolidin-2-one.

[0046] 1-(2-hydroxyethyl)pyrrolidin-2-one has a particularly high affinity with the specific dye, and thus, by containing 1-(2-hydroxyethyl)pyrrolidin-2-one, the solubility of the specific dye in the ink composition is improved, and the deposition of the dye in the flow path of the inkjet recording device can be more effectively suppressed, and the color of the recording part formed on the recording medium can be more effectively suppressed from deviating from the target color.

[0047] The content of 1-(2-hydroxyethyl)pyrrolidin-2-one in the ink composition is preferably 1.0% by mass or more, more preferably 1.2% by mass or more and 6.0% by mass or less, and even more preferably 1.5% by mass or more and 5.0% by mass or less. This makes the above-mentioned effects more pronounced.

[0048] [1-1-2-1-5] Other water-soluble organic solvents The ink composition may further contain water-soluble organic solvents other than those mentioned above. Hereinafter, such organic solvents will be referred to as "other water-soluble organic solvents" in this section.

[0049] Other water-soluble organic solvents include, for example, glycerin; glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; nitrogen-containing solvents such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone; and alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, 2-butanol, tert-butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol. The other water-soluble organic solvents may be used alone or in combination of two or more kinds.

[0050] The content of other water-soluble organic solvents in the ink composition is preferably 3.0% by mass or more and 30.0% by mass or less, more preferably 5.0% by mass or more and 25.0% by mass or less, and even more preferably 7.0% by mass or more and 20.0% by mass or less.

[0051] [1-1-2-1-6] Other ingredients The ink composition may further contain components other than those described above. Hereinafter, such components will be referred to as "other components" in this section.

[0052] Examples of other components include dispersants, surfactants, dissolution aids, viscosity adjusters, pH adjusters, antioxidants, preservatives, fungicides, corrosion inhibitors, and chelating agents.

[0053] However, the content of other components in the ink composition is preferably 7.0% by mass or less, more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

[0054] [1-1-2-2] Elastomer tube In the inkjet recording device according to the present invention, at least a part of the flow path for the ink composition is constituted by an elastomer tube, and the elastomer tube has an inner surface with a surface roughness Ra of 10 μm or less and an inner diameter of 5 mm or more.

[0055] The surface roughness Ra of the inner surface of the elastomer tube may be 10 μm or less, preferably 1 μm to 10 μm, more preferably 2 μm to 10 μm, and even more preferably 3 μm to 10 μm.

[0056] This makes it possible to more significantly exhibit the above-mentioned effects, and also effectively suppresses the difficulty and cost of manufacturing the elastomer tube from increasing, and also makes it possible to improve the ease of bending the elastomer tube.

[0057] The inner diameter of the elastomer tube may be 5 mm or more, but is preferably 6 mm to 50 mm, more preferably 7 mm to 40 mm, and even more preferably 8 mm to 30 mm.

[0058] This allows the above-mentioned effects to be more pronounced. It is presumed that the effect of water evaporation from the tube wall surface is reduced by the inner diameter of 5 mm or more. In addition, the size of the pump for distributing the ink composition can be more effectively prevented, and the size of the inkjet recording device can be more effectively prevented. In addition, the occurrence of problems such as nozzle missing due to insufficient flow rate of the ink composition by the pump can be more effectively prevented.

[0059] The elastomer tube is a general term for thermoplastic elastomers or thermosetting elastomers. Examples of materials constituting thermoplastic elastomers include olefin-based, urethane-based, ester-based, styrene-based, vinyl chloride-based, and amide-based resins. Examples of materials constituting thermosetting elastomers include natural rubber, silicone rubber, ethylene propylene rubber, ethylene propylene diene rubber, urethane rubber, acrylic rubber, and butyl rubber. These materials may be a single material or a combination of two or more materials. The structure of the tube may be a single layer structure or a laminated structure. The elastomer tube may also contain additives such as softeners, lubricants, surfactants, antioxidants, adhesion promoters, and pigments.

[0060] It is preferable that the elastomer tube has a bent portion within the inkjet recording device.

[0061] In the bent portion of the elastomer tube, the gaps described above tend to widen, making it easier for the dye to enter and for water to evaporate, leading to a localized high concentration of the dye and other factors that make the dye more likely to accumulate, and in the past, this was particularly likely to cause problems with dye accumulation in these areas. In contrast, the present invention can effectively prevent the occurrence of such problems. Therefore, when the elastomer tube has a bent portion within the inkjet recording device, the effects of the present invention are more pronounced.

[0062] It is also preferable that the elastomer tube has a portion that is bent at an angle of 30° to 180° in the inkjet recording device. This makes the above-mentioned effects more pronounced.

[0063] In this specification, the term "bending angle" refers to the smaller of the angles formed at the intersection of the flow directions of the ink composition at both ends of the elastomer tube, with the fixed parts of the elastomer tube being the two ends. There may be cases where the intersection does not exist, but in such cases, it is defined as follows. When the flow direction of the ink composition is the same at both ends, it is defined as 0°. When the flow directions of the ink composition differ by 180°, it is defined as 180°. When it is in a twisted position, the flow direction of the ink composition is translated in a plane including the flow path direction to define the intersection and the angle formed therewith. In addition, when the elastomer tube is movable and the bending angle varies with time, the maximum bending angle is defined as the bending angle of the elastomer tube.

[0064] The bending angle of the elastomer tube in the inkjet recording device is preferably 30° to 180°, more preferably 50° to 180°, and even more preferably 70° to 180°. This makes the above-mentioned effects even more pronounced.

[0065] Moreover, the air permeability of the elastomer tube at 35° C. is preferably 60 μL / day or less, more preferably 50 μL / day or less, and even more preferably 40 μL / day or less.

[0066] This makes it possible to more effectively prevent water evaporation from the elastomer tube and more effectively prevent localized high concentration of the dye, which in turn makes it possible to more effectively prevent the dye from accumulating in the flow passage of the inkjet recording device and more effectively prevent the color of the recording portion formed on the recording medium from deviating from the target color.

[0067] The air permeation rate of the elastomer tube can be measured according to the following method. FIG. 1 is a schematic diagram for explaining a method for measuring the air permeation rate of a tube. As shown in FIG. 1, one end of an elastomer tube 46 cut to an arbitrary length is sealed with a pinch cock 302, and the other end of the elastomer tube 46 is connected to one tip of an L-shaped 1 mL measuring pipette 303. At this time, the elastomer tube 46 has no curved or bent parts, and is not subjected to stress such as tension except for the sealing part by the pinch cock 302 and the connection part to the L-shaped 1 mL measuring pipette 303. In addition, the other tip of the 1 mL measuring pipette 303 is inserted into a container 304 containing water. In the above state, the tube is left in an environment with a temperature of 35° C. and a relative humidity of 20%, and the scale of the measuring pipette is read at regular intervals to measure the amount of air that has permeated into the elastomer tube 46. The air permeability of the tube shown in this specification is the amount per 100 mm of tube length, and is expressed in units of "μL / day." The target temperature for determining the air permeability of the tube is 35°C, in order to confirm that sufficient effects can be obtained even in a normal temperature environment by evaluating under more severe conditions compared to the normal temperature environment (room temperature, 25°C) in which an inkjet recording device is used. The air permeability of the tube shown in this specification refers to the value measured under the above conditions, unless otherwise specified.

[0068] The length of the elastomer tube is preferably 1000 mm or more and 8000 mm or less, more preferably 1500 mm or more and 7500 mm or less, and even more preferably 2000 mm or more and 7000 mm or less.

[0069] This allows recording with the ink composition to be suitably performed even on larger recording media. Furthermore, when the elastomer tube is long as described above, the ink composition is likely to dry out in the elastomer tube in the past, and the above-mentioned problems are particularly likely to occur, but the present invention can effectively prevent the above-mentioned problems from occurring even when the elastomer tube is long as described above. In other words, when the length of the elastomer tube is within the above-mentioned range, the effects of the present invention are more pronounced.

[0070] [1-2] Other processes The inkjet recording method of the present invention may further include other steps in addition to the image forming step described above.

[0071] Examples of such processes include a pretreatment process for performing pretreatment on the recording medium, and posttreatment processes such as a heating process and a drying process for the recording medium to which the ink composition is attached.

[0072] [2] Inkjet recording device Next, the ink jet recording apparatus of the present invention will be described.

[0073] The inkjet recording device of the present invention includes an ink composition, an ink storage section in which the ink composition is stored, a recording head for ejecting the ink composition, and a flow path section for distributing the ink composition from the ink storage section to the recording head. The ink composition contains water and at least one colorant selected from the group consisting of CI Acid Red 407, CI Acid Blue 140, CI Acid Blue 161, and CI Acid Brown 298. At least a part of the flow path section is an elastomer tube, the surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, and the inner diameter of the elastomer tube is 5 mm or more.

[0074] This makes it possible to provide an inkjet recording device that can effectively prevent the dye from accumulating in the flow path of the inkjet recording device, and can effectively prevent the color of the recording part formed on the recording medium from deviating from the target color. In addition, the use of an elastomer tube makes it easier to assemble the inkjet recording device, which is also advantageous for miniaturizing the inkjet recording device.

[0075] The above-mentioned ink jet recording method of the present invention can be suitably carried out by using the ink jet recording apparatus of the present invention, which will be described in detail below.

[0076] Hereinafter, preferred embodiments of an inkjet recording apparatus will be described in detail with reference to the drawings.

[0077] Fig. 2 is a perspective view showing an example of the schematic configuration of an inkjet recording apparatus in a see-through state. Fig. 3 is a schematic view showing an example of the arrangement of a deaeration unit. Fig. 4 is a schematic view showing another example of the arrangement of a deaeration unit. Fig. 5 is a schematic view showing an example of a deaeration unit.

[0078] As shown in FIG. 2, the inkjet recording device 21 includes a housing 22 having a rectangular parallelepiped shape with the left-right direction as the longitudinal direction. FIG. 2 shows a simplified view of the inside of the housing 22 of the inkjet recording device 21 in a see-through state. A support table 23 with the left-right direction as the longitudinal direction is provided in a lower part near the rear in the housing 22, with its upper surface aligned substantially horizontally. A fabric P, which is an example of a recording medium, is supported on the upper surface of the support table 23 and transported forward in the transport direction. A guide shaft 24 extending along the left-right direction is installed above the support table 23 in the housing 22, and a carriage 26 having a recording head 25 on its lower surface side that ejects an ink composition is supported on the guide shaft 24. That is, the carriage 26 is supported so as to be freely movable back and forth in the left-right direction with respect to the guide shaft 24, with the guide shaft 24 inserted through a support hole 27 penetrating in the left-right direction.

[0079] A driving pulley 28 and a driven pulley 29 are rotatably supported at positions near both ends of the guide shaft 24 within the housing 22. An output shaft of a carriage motor 30 is connected to the driving pulley 28, and an endless timing belt 31, a part of which is connected to the carriage 26, is wound between the driving pulley 28 and the driven pulley 29. When the carriage 26 is driven by the carriage motor 30 to reciprocate along the left-right direction, which is the scanning direction for the fabric P, while being guided by the guide shaft 24 via the timing belt 31, an ink composition is ejected from the recording head 25 on the underside of the carriage 26 onto the fabric P, which is transported forward on the support table 23.

[0080] 2, a rectangular discharge port 32 is opened at a position on the front side of the housing 22 in front of the support stand 23, for discharging the fabric P, which has been recorded on by the ejection of the ink composition from the recording head 25 when it is transported on the support stand 23 inside the housing 22, to the front side. A rectangular plate-shaped discharge tray 33 capable of supporting the fabric P discharged from inside the housing 22 is provided at the discharge port 32 so as to be freely retractable forward, which is the discharge direction. A paper feed cassette 34 capable of accommodating a plurality of sheets of fabric P used for recording in a stacked state is attached to the lower side of the discharge tray 33 inside the discharge port 32 so as to be freely insertable and removable in the front-rear direction.

[0081] 2, an opening / closing door 35 having a rectangular front and upper surface and a right-angled triangular right side surface is provided on the front of the housing 22 at a position closer to the left-right end than the discharge port 32 (the right end in FIG. 2), and can be opened and closed in the front-rear direction around a rotation shaft 36 provided at the bottom of the opening / closing door 35 and extending in the left-right direction. A window 37 made of a rectangular transparent member is formed on the front of the opening / closing door 35, so that the user can view the inside of the housing 22, particularly the back side of the front of the opening / closing door 35, when the opening / closing door 35 is closed.

[0082] An ink supply unit 40 that supplies an ink composition to the recording head 25 is housed inside the housing 22 of the inkjet recording device 21 at a position behind the opening and closing door 35, i.e., at a position closer to the front and closer to an end (closer to the right end in this case). The ink supply unit 40 is a structure that includes ink tanks as a plurality of ink containing sections, particularly five ink tanks 41 to 45 in the illustrated configuration, and can be handled as a unit.

[0083] The ink supply unit 40 includes five ink tanks 41 to 45 serving as ink storage sections, each having a deformed box shape that is long in the front-rear direction, and five elastomer tubes 46 serving as ink supply tubes that are pulled out from the rear side of each of the ink tanks 41 to 45. The elastomer tubes 46 form flow paths that distribute the ink composition from the ink tanks 41 to 45, which are ink storage sections, to the recording head 25.

[0084] In the illustrated configuration, the ink supply unit 40 includes a rectangular parallelepiped ink refill adapter 47 to which the ink tanks 41 to 45 are attached in a state where they are all assembled together. The ink refill adapter 47 is attached to stepped portions 48 cut out and formed in the upper front half portions of all the ink tanks 41 to 45 when all the ink tanks 41 to 45 are arranged side by side with their thickness direction being the left-right direction, thereby being integrated with the ink tanks 41 to 45. The ink refill adapter 47 is configured to be connected to an ink container such as a pack, bottle, or tank that contains an ink composition, so that the ink composition in the ink container can be refilled to the ink tanks 41 to 45.

[0085] In the inkjet recording apparatus of the present invention, the ink composition preferably satisfies the condition described above in [1-1-2-1], and the elastomer tube preferably satisfies the condition described above in [1-1-2-2]. This provides the same effect as described above.

[0086] The inkjet recording apparatus 21 preferably further includes a degassing section (not shown in FIG. 2) downstream of the flow path connected to the ink storage section, for reducing the amount of gas contained in the ink composition.

[0087] As a result, even in the case of an inkjet recording device having a CISS system in which the ink composition is placed in a degassed saturated state or a sub-tank, the initial filling property can be improved by degassing within the inkjet recording device, and nozzle missing caused by air bubbles can be more effectively suppressed. On the other hand, in the degassing section, the cross-sectional area of ​​the flow path section is usually reduced in order to increase the degassing efficiency of the ink composition, and the proportion of the surface area of ​​the ink composition that contacts the inside of the flow path section increases. For this reason, in the past, when a degassing section was provided, the moisture in the ink composition was easily evaporated, and the dye was particularly likely to accumulate in the flow path section. In contrast, in the present invention, even when a degassing section is provided, the occurrence of the above-mentioned problems can be effectively suppressed. In other words, when the inkjet recording device 21 has a degassing section, the effect of the present invention is more pronounced.

[0088] In the embodiment shown in FIG. 3, a degassing module 204 is provided as a degassing section in a flow path 214 connecting the ink tank 41 (42 to 45) and the ejection port of the recording head 25, and reduces the amount of gas contained in the inflowing ink composition.

[0089] An example of the degassing module 204 is a hollow fiber degassing module. An example of a commercially available hollow fiber degassing module is EF-G3 manufactured by DIC Corporation.

[0090] In the embodiment shown in FIG. 4, the recording head 25 receives the ink composition from the ink tank 41 (42-45) via the outgoing path 214A, which is a part of the flow path, and ejects the ink composition. At this time, the ink composition, the gas content of which has been reduced by the degassing module 204, which is a degassing unit provided in the outgoing path 214A, is supplied to the recording head 25. Thereafter, the ink composition that has not been ejected by the recording head 25 is supplied again to the degassing module 204 via the returning path 214B, which is a part of the flow path. As a result, even if the gas content increases due to the passage of time or gas absorption in the flow path, the gas content can be reduced again.

[0091] As the degassing module 204, for example, one including a member made of adhesive can be used.

[0092] A degassing chamber (not shown) into which the ink composition flows, and a decompression chamber (not shown) that is in contact with the degassing chamber via a separation membrane that is selectively permeable to gases such as air but not permeable to liquids such as the ink composition may be provided within the degassing module 204. In this case, an adhesive is usually used in at least one of the members that constitute the degassing chamber or the decompression chamber, and the connection between the degassing chamber and the flow path portion.

[0093] When the pressure in the decompression chamber is reduced by the decompression pump, air bubbles that have been mixed into the ink composition in the degassing chamber and gases such as oxygen and nitrogen that have been dissolved in the ink composition are removed from the ink composition. This prevents air bubbles from being mixed into the ink composition, and the ink composition with a lower amount of dissolved gas than the ink composition supplied to the degassing module 204 can be supplied to the recording head 25 and ejected from the recording head 25.

[0094] The adhesive is preferably an epoxy adhesive. The epoxy adhesive is preferably one obtained by reacting an epoxy resin with a curing agent.

[0095] As the epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, aliphatic type epoxy resin, glycidylamine type epoxy resin, etc. can be used, with bisphenol A type epoxy resin being preferred.

[0096] Specific examples of epoxy resins include jER825, jER827, jER828, jER828EL, jER828US, jER828XA, jER834, jER801N, jER801PN, jER802, jER811, jER813, jER816A, jER816C, jER819, jER1001, jER1002, and jER1003 (all manufactured by Mitsubishi Chemical Corporation).

[0097] As the curing agent, for example, aliphatic polyamines, polyaminoamides, polymercaptans, aromatic polyamines, acid anhydrides, phenol novolac resins, dicyandiamide, diamine compounds, etc. can be used, with diamine compounds and polyamidoamines being preferred.

[0098] More specifically, examples of the curing agent include 1,3-BAC (manufactured by Mitsubishi Gas Chemical Company, Inc.), MXDA (meta-xylylenediamine) (manufactured by Mitsubishi Gas Chemical Company, Inc.), triethylenetetramine, diaminodiphenylmethane, 4-methylhexahydrophthalic anhydride, phenol novolac resin, and dicyandiamide.

[0099] When the adhesive is obtained by the reaction of an epoxy resin with a curing agent, the amounts of these can be adjusted as appropriate, but the content of the curing agent per 100 parts by mass of the epoxy resin is preferably 10 parts by mass or more and 200 parts by mass or less, more preferably 50 parts by mass or more and 150 parts by mass or less, and even more preferably 70 parts by mass or more and 120 parts by mass or less.

[0100] The adhesive can be applied or filled to the area where adhesion is desired, and cured by heating as necessary. In this embodiment, the adhesive refers to the cured adhesive.

[0101] In the degassing module shown in Fig. 5, the adhesive bonds the hollow fibers and the degassing module in the degassing module and also serves to seal the ink from flowing into the degassing pump. By reducing the pressure inside the hollow fibers with the degassing pump, dissolved oxygen, nitrogen, and the like in the ink can be suitably removed through the hollow fibers. The adhesive is used in the flow path that comes into contact with the ink composition.

[0102] [3] Recorded material Next, the recorded matter according to the present invention will be described. The recorded matter according to the present invention is produced by using the inkjet recording method and inkjet recording apparatus according to the present invention described above.

[0103] The recorded matter according to the present invention is one in which the color tone of the recorded portion formed on the recording medium is effectively prevented from deviating from the target color tone.

[0104] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these. EXAMPLES

[0105] Next, specific examples of the present invention will be described, but the present invention is not limited to the following examples.

[0106] [4] Manufacture of inkjet recording devices Example 1 In a mixing tank, CI Acid Red 407, 2-pyrrolidone, glycerin, disodium ethylenediaminetetraacetate, Olfin PD002W (manufactured by Nissin Chemical Industry Co., Ltd.), tripropanolamine, Proxel XL-2 (manufactured by ARXADA), and ion-exchanged water were added in the prescribed ratio, mixed and stirred, and then mixed and stirred for 2 hours with a stirrer. After that, the mixture was filtered through a membrane filter with a pore size of 5 μm, and then further filtered with N 2 A degassing treatment was carried out so that the dissolved amount became 10 ppm or less, thereby obtaining an ink composition.

[0107] An ink-jet printing machine, Monna-Lisa (ML-64000) manufactured by Seiko Epson Corporation, was modified and filled with the above-mentioned ink composition to obtain an ink-jet recording device as shown in FIG.

[0108] This inkjet recording device did not include a degassing module, but instead included an elastomer tube in the flow path, which had an inner surface roughness Ra of 10 μm, an air permeability of 30 μL / day, an inner diameter of 10 mm, a length of 6000 mm, and a bending angle of 100° within the inkjet recording device.

[0109] (Examples 2 to 63) An ink jet recording device was manufactured in the same manner as in Example 1, except that the composition of the ink composition and the conditions of the elastomer tube were as shown in Figs.

[0110] (Example 64) An inkjet recording apparatus was manufactured in the same manner as in Example 1, except that a degassing module (PF-001D, manufactured by DIC Corporation) was provided.

[0111] (Examples 65 to 67) An ink jet recording apparatus was produced in the same manner as in Example 64, except that the composition of the ink composition and the conditions of the elastomer tube were as shown in Figs.

[0112] (Comparative Examples 1 to 8) An ink jet recording apparatus was manufactured in the same manner as in Example 1, except that the composition of the ink composition and the conditions of the elastomer tube were as shown in FIG.

[0113] Comparative Example 9 An ink jet recording apparatus was produced in the same manner as in Example 64, except that the composition of the ink composition and the conditions of the elastomer tube were as shown in FIG.

[0114] [5] Evaluation The following evaluations were carried out using the inkjet recording apparatuses according to the above-mentioned respective Examples and Comparative Examples.

[0115] [5-1] Initial filling evaluation During the manufacture of the inkjet recording devices of the Examples and Comparative Examples, the ink composition was filled and a nozzle check was carried out. In this nozzle check, the percentage of nozzles that ejected normally without missing ink or deflected ink was determined and evaluated according to the following criteria.

[0116] A: The percentage of nozzles that eject normally is 98% or more. B: The percentage of nozzles that eject normally is 95% or more but less than 98%. C: The percentage of nozzles that eject normally is less than 95%.

[0117] [5-2] Evaluation of nozzle failure Using the inkjet recording apparatus of each of the Examples and Comparative Examples, a solid print (1200 x 1200 dpi, all nozzles ejecting, normal mode, duty 100%, 1500 mm width) of 10 m was performed on a fabric (nylon / polyurethane blend) as a recording medium, and then printing was stopped for 1 hour. This cycle was repeated 10 times.

[0118] For each of the above-mentioned Examples and Comparative Examples, the color difference was determined as follows for the printed area of ​​the first recorded material and the last recorded material obtained.

[0119] That is, for each recorded material, measurements were taken using a spectrodensitometer (product name "Spectrolino", manufactured by X-RITE) under the following conditions: light source: D65, status: DIN_NB, viewing angle: 2 degrees, filter: UV. * , a * , b * The value was calculated for the first recording. * , a * , b * The values ​​are, respectively, L1 * , a1 *, b1 * Finally, the L of the obtained records * , a * , b * The values ​​are, respectively, L2 * , a2 * , b2 * Then, ΔE = {(L2 * -L1 * ) 2 +(a2 * -a1 * ) 2 +(b2 * -b1 * ) 2} 1 / 2 The color difference ΔE was calculated according to the formula above, and the color change was evaluated according to the following criteria. The smaller the ΔE, the more the nozzle missing is suppressed and the more the color change is suppressed. In particular, an evaluation result of B or higher can be said to have achieved a good effect.

[0120] A++: ΔE is less than 1.0. A+: ΔE is 1.0 or more and less than 2.0. A: ΔE is 2.0 or more and less than 3.0. B: ΔE is 3.0 or more and less than 5.0. C: ΔE is 5.0 or more and less than 6.0. D: ΔE is 6.0 or more.

[0121] These results are shown together in FIGS. 6 to 11, together with the configurations of the inkjet recording apparatuses according to the respective Examples and Comparative Examples.

[0122] In addition, in Figures 6 to 11, CI Acid Red 407 is represented as "AR407", CI Acid Blue 140 is represented as "AB140", CI Acid Blue 161 is represented as "AB161", CI Acid Brown 298 is represented as "ABr298", CI Acid Red 37 is represented as "AR37", CI Acid Blue 1 is represented as "AB1", CI Acid Brown 75 is represented as "ABr75", 2-pyrrolidone is represented as "2py", glycerin is represented as "Gly", disodium ethylenediaminetetraacetate is represented as "EDTA", the solid content of Olfine PD002W (manufactured by Nissin Chemical Industry Co., Ltd.) is represented as "PD002W", tripropanolamine is represented as "TPA", Proxel The solid content of XL-2 (manufactured by ARXADA) was indicated as "XL2", 1-(2-hydroxyethyl)pyrrolidin-2-one as "HEP", triethylene glycol as "TEG", and triethylene glycol monobutyl ether as "TEGMBE".

[0123] As is clear from Figures 6 to 11, excellent results were obtained in each of the Examples, whereas satisfactory results were not obtained in each of the Comparative Examples.

[0124] In addition, inkjet recording devices were manufactured in the same manner as in each of the above Examples, except that the length of the elastomer tube was changed in various ways within the range of 1000 mm or more and 8000 mm or less, and the same evaluations as above were performed on these devices, and the same results as above were obtained. [Explanation of symbols]

[0125] 21...inkjet recording device, 22...casing, 23...support stand, 24...guide shaft, 25...recording head, 26...carriage, 27...support hole, 28...driving pulley, 29...driven pulley, 30...carriage motor, 31...timing belt, 32...discharge port, 33...discharge tray, 34...paper feed cassette, 35...opening door, 36...rotating shaft, 37...window, 40...ink supply unit, 41-45...ink tank, 46...elastomer tube, 47...ink supply adapter, 48...step, 204...deaeration module, 214...flow path, 214A...outgoing path, 214B...return path, 302...pinch cock, 303...1mL measuring pipette, 304...container, P...recording medium

Claims

1. an image forming step of forming an image by applying the ink composition ejected from the recording head onto a recording medium using an inkjet recording apparatus including an ink composition, an ink storage section in which the ink composition is stored, a recording head for ejecting the ink composition, and a flow path section for distributing the ink composition from the ink storage section to the recording head, The ink composition contains a colorant including at least one selected from the group consisting of C.I. Acid Red 407, C.I. Acid Blue 140, C.I. Acid Blue 161, and C.I. Acid Brown 298, and water; At least a part of the flow path is an elastomer tube, The surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, The inkjet recording method, wherein the elastomer tube has an inner diameter of 5 mm or more.

2. The ink jet recording method according to claim 1 , wherein the elastomer tube has a portion bent at an angle of 30° or more and 180° or less.

3. an ink jet recording apparatus comprising: an ink composition; an ink storage section for storing the ink composition; a recording head for ejecting the ink composition; and a flow path section for distributing the ink composition from the ink storage section to the recording head; The ink composition contains a colorant including at least one selected from the group consisting of C.I. Acid Red 407, C.I. Acid Blue 140, C.I. Acid Blue 161, and C.I. Acid Brown 298, and water; At least a part of the flow path is an elastomer tube, The surface roughness Ra of the inner surface of the elastomer tube is 10 μm or less, The inner diameter of the elastomer tube is 5 mm or more.

4. The inkjet recording apparatus according to claim 3 , wherein the elastomer tube has a portion bent at an angle of 30° or more and 180° or less.

5. The ink jet recording apparatus according to claim 3 , further comprising a deaeration section downstream of the flow path section connected to the ink storage section.

6. The inkjet recording apparatus according to claim 3 , wherein the ink composition further contains a glycol ether.

7. The inkjet recording apparatus according to claim 6 , wherein the content of the glycol ether in the ink composition is 3.0% by mass or more.

8. 5. The ink jet recording apparatus according to claim 3, wherein the ink composition further contains 1-(2-hydroxyethyl)pyrrolidin-2-one.

9. 9. The inkjet recording apparatus according to claim 8, wherein the content of the 1-(2-hydroxyethyl)pyrrolidin-2-one in the ink composition is 1.0% by mass or more.

10. 5. The ink jet recording apparatus according to claim 3, wherein the elastomer tube has an air permeability of 60 [mu]L / day or less at 35[deg.] C.

11. 5. The ink jet recording apparatus according to claim 3, wherein the inner diameter of the elastomer tube is 50 mm or less.

12. 5. The inkjet recording apparatus according to claim 3, wherein the length of the elastomer tube is 1000 mm or more and 8000 mm or less.

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