Ink set, recording method and recording device

Abstract

Provided are an ink set, a recording method, and a recording device having excellent color reproduction area, fluorescent color reproduction area, granularity, intermittent reliability, and storage stability. The ink set comprises: a cyan ink C1 having a fluorescent whitening intensity of 3.0 or more and an SP value of 12 to 18; a magenta ink M1 having a fluorescent whitening intensity of 3.0 or more and an SP value of 12 to 18; a yellow ink Y1 having a fluorescent whitening intensity of 3.0 or more and an SP value of 12 to 18; a cyan ink C2 having a fluorescent whitening intensity of less than 3.0 and an SP value of 12 to 18; a magenta ink M2 having a fluorescent whitening intensity of less than 3.0 and an SP value of 12 to 18; and a yellow ink Y2 having a fluorescent whitening intensity of less than 3.0 and an SP value of 12 to 18, and the unit of the SP value is (cal / cm 3 ) 1 / 2 The above SP value is a value obtained by turbidity point titration using a water / acetone mixed solution.

Description

Technical Field

[0001] The present invention relates to an ink set, a recording method and a recording device. Background Art

[0002] The inkjet recording method can record high-definition images with a relatively simple device, and has achieved rapid development in various aspects. Among them, various studies have been conducted on schemes for more stably obtaining high-quality recorded objects. For example, Patent Document 1 describes an ink set having a predetermined cyan ink and a yellow ink for the purpose of providing a blue dye having good light resistance and used for dyeing various recording media, preferably fibers, more preferably polyester fibers, wherein the predetermined cyan ink and the yellow ink respectively contain a water-insoluble colorant and a liquid medium selected from water or an organic solvent.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Application Publication No. 2019-001870.

[0006] However, although the invention described in Patent Document 1 describes that the cyan ink contains a predetermined colorant in order to expand the color reproduction area in inkjet printing, it does not describe that the yellow ink also contains a predetermined colorant, and it cannot be said that the expansion of the color reproduction area is fully achieved. Summary of the invention

[0007] The ink set of the present invention comprises: a cyan ink C1, the fluorescent whitening intensity is above 3.0, and the SP value is 12 to 18 (cal / cm 3 ) 1 / 2 Magenta ink M1, fluorescent whitening intensity is above 3.0, SP value is 12~18 (cal / cm 3 ) 1 / 2 ; Yellow ink Y1, fluorescent whitening intensity is above 3.0, SP value is 12~18 (cal / cm 3 ) 1 / 2 ; Cyan ink C2, fluorescent whitening intensity less than 3.0, SP value 12 ~ 18 (cal / cm 3 ) 1 / 2 Magenta ink M2, fluorescent whitening intensity less than 3.0, SP value 12 ~ 18 (cal / cm 3 ) 1 / 2 ; and yellow ink Y2, fluorescent whitening intensity less than 3.0, SP value of 12 ~ 18 (cal / cm 3 ) 1 / 2 The above SP value is a value obtained by turbidity point titration using a water / acetone mixed solution.

[0008] In addition, the recording method of the present invention includes an ink adhesion process of ejecting the above-mentioned ink group from the inkjet head and making it adhere to the recording medium. In the ink adhesion process, the nozzle opening time is more than 1 minute. The above-mentioned nozzle opening time is the time that a part of the nozzle of the inkjet head is in an open state from the time when ink is ejected from the part of the nozzle to the time when the part of the nozzle is sucked and cleaned.

[0009] Furthermore, the recording apparatus of the present invention is a recording apparatus including an inkjet head having nozzles for ejecting each ink included in the ink set, and a cleaning unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of a recording device that can be used in this embodiment.

[0011] Explanation of symbols:

[0012] 1. Serial printer; 2. Inkjet head; 3. Ink cartridge; 4. Slide; 5. Platen; 6. Heating mechanism; 7. Slide moving mechanism; 8. Conveying unit; 9. Guide rod; 10. Linear encoder; 11. Cover part; 12. Cleaning unit; M, recording medium; CONT, control unit; S1, S2, main scanning direction; T1, T2, sub-scanning direction. DETAILED DESCRIPTION

[0013] Below, as needed, refer to the attached Figure 1 While an embodiment of the present invention (hereinafter referred to as "the present embodiment") is described in detail, the present invention is not limited thereto and various modifications are possible without departing from the gist thereof. In addition, in the drawings, the same symbols are marked for the same elements, and repeated descriptions are omitted. In addition, as for the positional relationship such as up, down, left, and right, unless otherwise specified, the positional relationship shown in the drawings is used as a reference. Moreover, the dimensional ratios in the drawings are not limited to the ratios shown in the drawings.

[0014] 1. Ink set

[0015] The ink set of this embodiment comprises: a cyan ink C1 having a fluorescent whitening intensity of 3.0 or more and an SP value of 12 to 18 (cal / cm 3 ) 1 / 2 Magenta ink M1, fluorescent whitening intensity is above 3.0, SP value is 12~18 (cal / cm 3 ) 1 / 2 ; Yellow ink Y1, fluorescent whitening intensity is above 3.0, SP value is 12~18 (cal / cm 3 ) 1 / 2 ; Cyan ink C2, fluorescent whitening intensity less than 3.0, SP value 12 ~ 18 (cal / cm3 ) 1 / 2 Magenta ink M2, fluorescent whitening intensity less than 3.0, SP value 12 ~ 18 (cal / cm 3 ) 1 / 2 ; and yellow ink Y2, fluorescent whitening intensity less than 3.0, SP value of 12 ~ 18 (cal / cm 3 ) 1 / 2 In addition, the SP value can also be 12 to 18 (cal / cm 3 ) 1 / 2 The black ink B, SP value is 12 to 18 (cal / cm 3 ) 1 / 2 Orange ink O, SP value is 12~18(cal / cm 3 ) 1 / 2 The other inks are preferably eight or more in total. In the ink set, the SP value is a value obtained by turbidity titration using a water / acetone mixed solution.

[0016] In the present embodiment, the fluorescent whitening intensity refers to a numerical value represented by the following formula (1), and can be measured using a spectrophotometer FD-7 (manufactured by Konica Minolta Holdings).

[0017] Fluorescent whitening intensity ΔB = B(D65)-B(UVcut)……(1)

[0018] (Wherein, B(D65) is the brightness of the D65 light source, and B(UVcut) is the brightness of the D65 light source obtained by cutting off the wavelength below 410 nm.) In addition, the D65 light source refers to the standard light source defined by the International Commission on Illumination. In order to avoid the influence of the recording medium, the ink adhesion amount is preferably set to 15 g / m 2 The fluorescent whitening intensity of the ink is measured as above. It is more preferable to set the ink adhesion amount to 21 g / m 2 To carry out the measurement.

[0019] In addition, the SP value of each ink in the ink set represents an SP value obtained by a turbidity point titration method using a water / acetone mixed solution, the Hansen SP value of the water-soluble organic solvent represents an SP value based on the Hansen method, and the average Hansen SP value of the water-soluble organic solvent represents a weighted average of the Hansen SP values ​​of each water-soluble organic solvent in the ink. The reason for using two types of SP values ​​in this embodiment is described in detail below.

[0020] Since the SP value of ink contains multiple components, it is difficult to define it using the Hansen method of estimating solubility from the molecular structure of one molecule, so it is preferable to use the SP value obtained by the turbidity titration method. In addition, since it can be considered that the SP value obtained by the turbidity titration method evaluates the state similar to the evaluation of the dispersion stability of the ink in the state where the ink becomes rich in solvent as it dries in the nozzle, it can be said that the SP value obtained by the turbidity titration method is appropriate for the SP value of the ink from the viewpoint of solving the technical problem.

[0021] On the other hand, regarding the SP value of a water-soluble organic solvent, depending on the type of solvent, sometimes the turbidity point titration method cannot be used because white turbidity or precipitation does not occur due to a change in the water / acetone ratio, and the solubility of a water-soluble organic solvent can be easily estimated from its molecular structure. Therefore, it is considered preferable to use the SP value based on the Hansen method.

[0022] Here, the SP value obtained by the turbidity point titration method in this embodiment is described.

[0023] In general, the SP value obtained by the turbidity point titration method refers to a value calculated by dropping a poor solvent into each ink and finding the amount of the poor solvent required to produce turbidity according to the following formula (2) of KWSUH, JM CORBET (see Journal of Applied Polymer Science, 12, 2359, 1968). However, in the present embodiment, since the colored ink is used as the measurement object, it is difficult to directly determine the turbidity by visual inspection. Therefore, the amount of the poor solvent required to produce a precipitate of the color material is determined instead of the turbidity, and it is defined as the value calculated according to the following formula (2) of KWSUH, JM CORBET (see Journal of Applied Polymer Science, 12, 2359, 1968).

[0024] In the specification, the value obtained by the turbidity titration method defined in this way is referred to as an SP value obtained by the turbidity titration method.

[0025] At this time, two poor solvents, poor solvent 1 with a low SP value and poor solvent 2 with a high SP value, are used as the poor solvents. However, in the present embodiment, water / acetone mixed solutions with different mixing ratios are used as the poor solvent 1 and the poor solvent 2, respectively, and the SP value of each ink is measured by the turbidity point titration method.

[0026] SP value = (V ml 1 / 2 ·δ ml +V mh 1 / 2 ·δmh ) / (V ml 1 / 2 +V mh 1 / 2 )……(2)

[0027] Here, the meanings of the symbols in the above calculation formula are as follows.

[0028] V ml =v 1 ×v 2 / ((1-V L )×v 2 +V L ×v 1 )

[0029] V mh =v 1 ×v 3 / ((1-V H )×v 3 +V H ×v 1 )

[0030] T: The amount of solvent required to dissolve the ink components (ml)

[0031] L: Titration of poor solvent 1 (ml)

[0032] H: Titration of poor solvent 2 (ml)

[0033] V L =L / (T+L)

[0034] V H =H / (T+H)

[0035] v 1 : Molar molecular volume of the solvent used to dissolve the ink components (cm 3 / mol)

[0036] v 2 : Molar molecular volume of poor solvent 1 (cm 3 / mol)

[0037] v 3 : Molar molecular volume of poor solvent 2 (cm 3 / mol)

[0038] δ ml =δ T ×T / (T+L)+δ L ×L / (T+L)

[0039] δ mh =δ T ×T / (T+H)+δH ×H / (T+H)

[0040] δ T : SP value of the solvent used to dissolve the ink components

[0041] δ L : SP value of poor solvent 1

[0042] δ H : SP value of poor solvent 2.

[0043] In addition, the molar molecular volumes (cm 3 / mol) are acetone: 74.4, water: 18, and the SP values ​​of acetone and water (deionized water) are acetone: 9.75, water: 23.4.

[0044] In addition, the SP value obtained by Hansen in this embodiment (referred to as "Hansen SP value") is described. The Hansen SP value in this embodiment refers to the solubility parameter based on the Hansen method. The Hansen method is to classify the SP value δ into three terms, expressed as δ 2 =δ d 2 +δ p 2 +δ h 2 The method used to calculate δ d ,δ p ,δ h They are the solubility parameters equivalent to the dispersion force term, dipole force term, and hydrogen bond force term respectively.

[0045] In addition, the units of SP value and Hansen SP value are (cal / cm 3 ) 1 / 2 The Hansen SP value is a value proposed by Hansen based on the idea that "two substances with similar intermolecular interactions are more likely to dissolve each other". In addition to being estimated by calculation, it can also be obtained by experiment and experience, and this value is recorded in a large number of documents. In this embodiment, the Hansen SP value can be derived using Hansen-Solubility HSPiP as calculation software.

[0046] The ink in the present embodiment refers to ink that is ejected from an inkjet head by an inkjet method and is made to adhere to a recording medium.

[0047] Hereinafter, each ink included in the ink set according to the present embodiment will be described in detail.

[0048] 1.1. Cyan ink

[0049] The cyan ink of the present embodiment includes two cyan inks C1 and C2 having SP values ​​within a predetermined range and different fluorescent whitening intensities. By including two cyan inks C1 and C2 having different fluorescent whitening intensities, the color reproduction area is expanded and the particle size is improved. In addition, by using the cyan inks C1 and C2, the color reproduction of high chromaticity (hereinafter referred to as "fluorescent color reproduction area") that is difficult to reproduce with inks with low fluorescent whitening intensity can be further improved, and the light resistance of the cyan ink that is difficult to achieve with inks with low fluorescent whitening intensity can also be improved.

[0050] In addition, in an ink set where the number of colors is increased in order to expand the color reproduction area, the open state of the nozzles that are not capped and do not eject will be prolonged anyway. In addition, the time until suction cleaning is prolonged due to the large size of the inkjet head. Therefore, the nozzles are easily clogged and the intermittent reliability is reduced. In contrast, by making the SP value within a predetermined range, the intermittent reliability can be further improved even if the inkjet head is enlarged due to the presence of multiple inks and the nozzle opening time is long, and the storage stability is also improved.

[0051] In particular, when using inks of the same color, the ink used for the purpose of expanding the color reproduction area is used for printing at a low frequency and in a low ejection amount, so that intermittent reliability is more likely to decrease. Therefore, the present invention is particularly useful.

[0052] The color material contained in the cyan ink is not particularly limited, but examples thereof include compounds represented by the following formula (I), CI Disperse Blue 3, 5, 6, 7, 9, 14, 16, 19, 20, 24, 26, 26:1, 27, 35, 43, 44, 52, 54, 55, 56, 58, 60, 61, 62, 64, 64:1, 71, 72, 72:1 、73、75、77、77:1、79、81、81:1、82、83、85、87、88、90、91、93、94、95、96、99、102、106、108、112、113、115、118、120、122、125、128、130、131、139、141、142、143、145、 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 241, 257, 259, 267, 268, 27 0, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 354, 359, 360, 367, CI Solvent Blue 2, 11, 14, 24, 25, 35, 36, 38, 48, 55, 59, 63, 67, 68, 70, 73, 83, 105, 111, 132, etc.

[0053]

Chemical formula 1

[0054]

[0055] (In formula (I), R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, the hydrogen atom of the alkyl group may be substituted by an alkoxy group having 1 to 6 carbon atoms, and X represents an oxygen atom or an imino group)

[0056] The alkyl group having 1 to 18 carbon atoms represented by R is not particularly limited, and examples thereof include straight-chain alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl and dodecyl; branched-chain alkyl groups such as isopropyl, isobutyl, tert-butyl, neopentyl, 2-hexyl, 2-octyl, 2-decyl and 2-dodecyl; and cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl and cyclododecyl.

[0057] The alkyl group represented by R has 1 to 18 carbon atoms, preferably 2 to 10 carbon atoms, and more preferably 3 to 8 carbon atoms.

[0058] Furthermore, the hydrogen atom of the alkyl group having 1 to 18 carbon atoms represented by R may be substituted with an alkoxy group having 1 to 6 carbon atoms. Such a group is not particularly limited, and examples thereof include groups represented by the following formula (II).

[0059] -C n H 2n -OC m H2 m+1 ……(II)

[0060] In formula (II), n is 1 to 18, preferably 2 to 10, and more preferably 3 to 8. In addition, m is 1 to 6, preferably 2 to 5, and more preferably 3 to 4.

[0061] For the cyan ink C1 and the cyan ink C2, one color material may be used alone, or a plurality of color materials may be used.

[0062] Hereinafter, the cyan ink C1 and the cyan ink C2 will be described in detail respectively.

[0063] 1.1.1. Cyan ink C1

[0064] The fluorescent whitening intensity of the cyan ink C1 is 3.0 or more, preferably 3.0-24, more preferably 3.0-18, and even more preferably 3.0-12.

[0065] As the color material contained in the cyan ink C1, it is preferred to contain at least one of CI Disperse Blue 60 and the compound represented by the above formula (I), and it is more preferred to contain the compound represented by the above formula (I). By containing such a color material, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the particle size is further improved.

[0066] The SP value of the cyan ink C1 is 12 to 18 (cal / cm 3 ) 1 / 2 , preferably 12 to 16 (cal / cm 3 ) 1 / 2 , more preferably 12 to 14 (cal / cm 3 ) 1 / 2 When the SP value of the cyan ink C1 is within such a range, there is a tendency for intermittent reliability and storage stability to be further improved.

[0067] The content of the colorant in the cyan ink C1 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and still more preferably 4.0 to 6.0% by mass relative to the total amount of the ink. By setting the content of the colorant in the cyan ink C1 to be within such a range, the color reproduction area and the fluorescent color reproduction area tend to be further improved, and the granularity tends to be further improved.

[0068] 1.1.2. Cyan ink C2

[0069] The fluorescent whitening intensity of the cyan ink C2 is less than 3.0, preferably 0.1 or more and less than 3.0, and more preferably 0.1 or more and less than 1.0.

[0070] The color material contained in the cyan ink C2 preferably contains at least one of CI Disperse Blue 359 and CI Disperse Blue 360. By containing such a color material, the color reproduction area and the fluorescent color reproduction range tend to be further improved, and the granularity tends to be further improved.

[0071] The SP value of cyan ink C2 is 12 to 18 (cal / cm 3 ) 1 / 2 , preferably 13 to 17 (cal / cm 3 ) 1 / 2 , more preferably 14 to 16 (cal / cm 3 ) 1 / 2 By setting the SP value of the cyan ink C2 to be within such a range, there is a tendency for intermittent reliability and storage stability to be further improved.

[0072] The content of the colorant contained in the cyan ink C2 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and still more preferably 4.0 to 6.0% by mass relative to the total amount of the ink. By setting the content of the colorant contained in the cyan ink C2 to such a range, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the granularity is further improved.

[0073] 1.2. Magenta ink

[0074] The magenta ink of this embodiment includes two magenta inks M1 and M2 whose SP values ​​are within a predetermined range and whose fluorescent whitening intensities are different. By including two magenta inks M1 and M2 with different fluorescent whitening intensities, as described above, the color reproduction area, fluorescent color reproduction area, and granularity are further improved, and intermittent reliability and storage stability are also improved.

[0075] There are no particular restrictions on the colorant contained in the magenta ink, but examples thereof include CI Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93、96、103、105、106、107、108、110、111、113、117、118、121、122、126、127、128、131、132、134、135、137、143、145、146、151、152、153、154、157、159、164、167、169、 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 257, 258, 277, 278, 279, 281, 288, 29 8, 302, 303, 310, 311, 312, 320, 324, 328, 362, 364, CI Solvent Red 1, 3, 7, 8, 9, 18, 19, 23, 24, 25, 27, 49, 100, 109, 121, 122, 125, 127, 130, 132, 135, 218, 225, 230, CI Vat Red 41, etc.

[0076] For the magenta ink M1 and the magenta ink M2, one color material may be used alone, or a plurality of color materials may be used.

[0077] Hereinafter, the magenta ink M1 and the magenta ink M2 will be described in detail respectively.

[0078] 1.2.1. Magenta ink M1

[0079] The fluorescent whitening intensity of the magenta ink M1 is 3.0 or more, preferably 3.0-24, more preferably 3.0-18, and even more preferably 3.0-12.

[0080] The magenta ink M1 contains at least one colorant, and as such a colorant, it preferably contains at least one of CI Disperse Red 364, CI Disperse Red 362, and CI Vat Red 41, and more preferably contains CI Disperse Red 364. By containing such a colorant, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the granularity is further improved.

[0081] The SP value of the magenta ink M1 is 12 to 18 (cal / cm 3 )1 / 2 , preferably 12 to 16 (cal / cm 3 ) 1 / 2 , more preferably 12 to 14 (cal / cm 3 ) 1 / 2 When the SP value of the magenta ink M1 is within such a range, there is a tendency that intermittent reliability and storage stability are further improved.

[0082] The content of the colorant contained in the magenta ink M1 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass relative to the total amount of the ink. When the content of the colorant contained in the magenta ink M1 is within such a range, the color reproduction area and the fluorescent color reproduction area tend to be further improved, and the granularity tends to be further improved.

[0083] 1.2.2. Magenta ink M2

[0084] The fluorescent whitening intensity of the magenta ink M2 is less than 3.0, preferably 0.1 or more and less than 3.0, and more preferably 0.1 or more and less than 1.0.

[0085] The magenta ink M2 contains at least one color material, and as such a color material, it is preferable to contain CI Disperse Red 60. By containing such a color material, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the granularity is further improved.

[0086] In addition, the SP value of the magenta ink M2 is 12 to 18 (cal / cm 3 ) 1 / 2 , preferably 14 to 18 (cal / cm 3 ) 1 / 2 , more preferably 15 to 17 (cal / cm 3 ) 1 / 2 When the SP value of the magenta ink M2 is within such a range, there is a tendency for intermittent reliability and storage stability to be further improved.

[0087] The content of the colorant contained in the magenta ink M2 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass relative to the total amount of the ink. By setting the content of the colorant contained in the magenta ink M2 to be within such a range, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the granularity is further improved.

[0088] 1.3. Yellow ink

[0089] The yellow ink of this embodiment includes two yellow inks Y1 and Y2 whose SP values ​​are within a predetermined range and whose fluorescent whitening intensities are different. By including two yellow inks Y1 and Y2 with different fluorescent whitening intensities, the color reproduction area, fluorescent color reproduction area, and granularity are further improved as described above, and intermittent reliability and storage stability are also improved.

[0090] The colorant contained in the yellow ink is not particularly limited, but examples thereof include CI Disperse Yellow 1, 3, 4, 5, 7, 8, 9, 13, 16, 23, 24, 30, 31, 33, 34, 39, 41, 42, 44, 49, 50, 51, 54, 56, 58, 60, 61, 63, 64, 66, 68, 71, 74, 76, 77, 78, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149 , 153, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 201, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232, 233, 245, CI Solvent Yellow 2, 6, 14, 16, 21, 25, 29, 30, 33, 51, 56, 77, 80, 88, 89, 93, 112, 113, 114, 116, 136, 150, 155, 157, 160, 163, 176, 179, 199, etc.

[0091] For the yellow ink Y1 and the yellow ink Y2, a single color material may be used alone, or a plurality of color materials may be used.

[0092] Hereinafter, the yellow ink Y1 and the yellow ink Y2 will be described in detail.

[0093] 1.3.1. Yellow ink Y1

[0094] The fluorescent whitening intensity of the yellow ink Y1 is 3.0 or more, preferably 3.0-24, more preferably 3.0-18, and even more preferably 3.0-12.

[0095] The yellow ink Y1 contains at least one color material, and as such a color material, it is preferred to contain at least one of CI Disperse Yellow 82, CI Disperse Yellow 184, CI Disperse Yellow 232, and CI Solvent Yellow 160, and more preferably contains at least one of CI Disperse Yellow 82 and CI Disperse Yellow 232. By containing such a color material, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved, and the granularity is further improved.

[0096] The SP value of the yellow ink Y1 is 12 to 18 (cal / cm 3 ) 1 / 2 , preferably 14 to 18 (cal / cm 3 ) 1 / 2 , more preferably 15 to 17 (cal / cm 3 ) 1 / 2 When the SP value of the yellow ink Y1 is within such a range, there is a tendency that intermittent reliability and storage stability are further improved.

[0097] The content of the colorant contained in the yellow ink Y1 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and still more preferably 4.0 to 6.0% by mass relative to the total amount of the ink. When the content of the colorant contained in the yellow ink Y1 is within such a range, the color reproduction area and the fluorescent color reproduction area tend to be further improved, and the granularity tends to be further improved.

[0098] 1.3.2. Yellow ink Y2

[0099] The fluorescent whitening intensity of the yellow ink Y2 is less than 3.0, preferably 0.1 or more and less than 3.0, and more preferably 0.1 or more and less than 1.0.

[0100] The yellow ink Y2 contains at least one colorant, and as such a colorant, it preferably contains at least one of CI Disperse Yellow 54 and CI Disperse Yellow 114. By containing such a colorant, the color reproduction area and fluorescent color reproduction range tend to be further improved, and the granularity tends to be further improved.

[0101] In addition, the SP value of yellow ink Y2 is 12 to 18 (cal / cm 3 ) 1 / 2 , preferably 12 to 16 (cal / cm 3 ) 1 / 2 , more preferably 12 to 14 (cal / cm 3 ) 1 / 2 When the SP value of the yellow ink Y2 is within such a range, there is a tendency for intermittent reliability and storage stability to be further improved.

[0102] The content of the colorant contained in the yellow ink Y2 is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and still more preferably 4.0 to 6.0% by mass relative to the total amount of the ink. By setting the content of the colorant contained in the yellow ink Y2 within such a range, there is a tendency that the color reproduction area and the fluorescent color reproduction area are further improved and the granularity is further improved.

[0103] 1.4. Black ink B

[0104] The ink set of this embodiment preferably further includes a black ink B. The black ink B contains at least one color material, and such a color material is not particularly limited, but examples thereof include CI Disperse Black 1, 3, 10, and 24. In addition, the ink set may be prepared by mixing cyan ink, magenta ink, and yellow ink at a predetermined ratio. By including such a black ink B, there is a tendency that the color reproduction area can be expanded, the fluorescent color reproduction area can be expanded, and the particle size can be improved.

[0105] The SP value of the black ink B is preferably 12 to 18 (cal / cm 3 ) 1 / 2 , more preferably 14 to 18 (cal / cm 3 ) 1 / 2 , more preferably 16 to 18 (cal / cm 3 ) 1 / 2 By setting the SP value within such a range, there is a tendency that intermittent reliability and storage stability can be improved even when the amount of ink is increased.

[0106] The content of the colorant contained in the black ink B is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass relative to the total amount of the black ink B. By setting the content of the colorant contained in the black ink B to be within such a range, an image with good color development properties that contributes to the expansion of the color reproduction area, the expansion of the fluorescent color reproduction range, and the improvement of the granularity can be formed.

[0107] 1.5. Orange ink O

[0108] The ink set of this embodiment preferably further comprises an orange ink O. The orange ink O contains at least one colorant, and such colorant is not particularly limited, but examples thereof include CI Disperse Orange 1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 46, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 60, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, and 142. By comprising such an orange ink O, there is a tendency that the color reproduction region can be expanded, the fluorescent color reproduction region can be expanded, and the particle size can be improved.

[0109] In addition, the SP value of the orange ink O is preferably 12 to 18 (cal / cm 3 ) 1 / 2 , more preferably 13 to 17 (cal / cm3 ) 1 / 2 , more preferably 14 to 16 (cal / cm 3 ) 1 / 2 By setting the SP value within such a range, there is a tendency that intermittent reliability and storage stability can be improved even when the amount of ink is increased.

[0110] The content of the colorant contained in the orange ink O is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass relative to the total amount of the orange ink O. By setting the content of the colorant contained in the orange ink O to be within such a range, an image with good color development properties that contributes to the expansion of the color reproduction area, the expansion of the fluorescent color reproduction range, and the improvement of the granularity can be formed.

[0111] 1.6. Other inks

[0112] The ink set of this embodiment preferably has other inks as needed. The other inks contain at least one colorant, and such colorants are not particularly limited, but examples thereof include CI Disperse Green 9, CI Disperse Brown 1, 2, 4, 9, 13, and 19.

[0113] In addition, the SP value of other inks is preferably 12 to 18 (cal / cm 3 ) 1 / 2 By setting the SP value within such a range, there is a tendency that intermittent reliability and storage stability can be improved even when the amount of ink is increased.

[0114] The content of the colorant contained in the other inks is preferably 1.0 to 10% by mass, more preferably 2.0 to 8.0% by mass, and further preferably 4.0 to 6.0% by mass relative to the total amount of the other inks. By making the content of the colorant in such a range, an image with good color development properties that contributes to the expansion of the color reproduction area, the expansion of the fluorescent color reproduction area, and the improvement of the granularity can be formed.

[0115] 1.7. Water-soluble organic solvents

[0116] Each ink of the ink set of the present embodiment may contain a water-soluble organic solvent. The water-soluble organic solvent is not particularly limited, but examples thereof include 1,2-pentanediol, glycerol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, triethylene glycol (2-[2-(2-methoxyethoxy)ethoxy]ethanol), triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monopropyl ether, tripropylene glycol, polypropylene glycol, polyethylene oxide polypropylene oxide glycol, 1,2-hexanediol, 1,2-heptanediol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-3-phenylene glycol, 1,2-hexanediol, 1,2-heptanediol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-3-phenylene glycol, 1,2-hexanediol, 1,2-heptanediol, 1,3-propanediol ... Polyols represented by diols such as oxy-1,2-propanediol, 3-(3-methylphenoxy)-1,2-propanediol, 3-hexyloxy-1,2-propanediol, 2-hydroxymethyl-2-phenoxymethyl-1,3-propanediol, 3-methyl-1,3-butanediol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, and 3-methyl-1,5-pentanediol; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, ε-caprolactam, and hydroxyethylpyrrolidone.

[0117] The content of the water-soluble organic solvent contained in each ink is preferably 10% by mass or more, more preferably 12% by mass or more, further preferably 13 to 35% by mass, further preferably 14 to 30% by mass, and further preferably 15 to 25% by mass relative to the total amount of each ink. By making the content of the humectant within such a range, there is a tendency to improve intermittent reliability and storage stability.

[0118] Furthermore, as the water-soluble organic solvent, it is preferred to use a water-soluble organic solvent having a Hansen SP value of 12 (cal / cm 3 ) 1 / 2 The above water-soluble organic solvent A and Hansen SP value are less than 12 (cal / cm 3 ) 1 / 2 of a water-soluble organic solvent B.

[0119] The content of the water-soluble organic solvent A is preferably 7.5 to 30% by mass, more preferably 10 to 25% by mass, and even more preferably 12.5 to 20% by mass, based on the total amount of each ink.

[0120] The content of the water-soluble organic solvent B is preferably 1.0 to 9.0% by mass, more preferably 2.0 to 8.0% by mass, and even more preferably 3.0 to 7.0% by mass, based on the total amount of each ink.

[0121] The ratio of the content of the water-soluble organic solvent A to the content of the water-soluble organic solvent B is preferably 1.0 to 6.0, more preferably 1.5 to 5.0, and even more preferably 2.0 to 4.0.

[0122] When the contents of the water-soluble organic solvents A and B are within the above ranges, intermittent reliability and storage stability tend to be further improved.

[0123] In addition, as a water-soluble organic solvent, it is preferable to use a water-soluble organic solvent having a Hansen SP value of 15 (cal / cm 3 ) 1 / 2 The above water-soluble organic solvents. Hansen SP value is 15 (cal / cm 3 ) 1 / 2 The content of the above water-soluble organic solvents is preferably 5% by mass or more, more preferably 6 to 15% by mass, and even more preferably 7 to 12.5% ​​by mass, based on the total amount of each ink.

[0124] 1.8. Surfactants

[0125] Each ink of the present embodiment may further contain a surfactant. The surfactant is not particularly limited, but examples thereof include silicone surfactants, acetylene glycol surfactants, and fluorine surfactants. Among these, silicone surfactants having high surface activity and low bubbling properties are preferred.

[0126] Examples of the silicone-based surfactant include polysiloxane-based compounds, polyether-modified silicone compounds, etc. The silicone-based surfactant may be used alone or in combination of two or more.

[0127] The acetylene glycol surfactant is not particularly limited, but is preferably one or more selected from, for example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and an alkylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and an alkylene oxide adduct of 2,4-dimethyl-5-decyne-4-ol and 2,4-dimethyl-5-decyne-4-ol. The acetylene glycol surfactant may be used alone or in combination of two or more.

[0128] The fluorine-based surfactant is not particularly limited, but examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, and perfluoroalkyl amine oxide compounds. The fluorine-based surfactant may be used alone or in combination of two or more.

[0129] The content of the surfactant is preferably 0.1 to 3.0% by mass, more preferably 0.2 to 2.0% by mass, and even more preferably 0.3 to 1.0% by mass relative to the total amount of each ink. When the content of the surfactant is within the above range, intermittent reliability tends to improve.

[0130] 1.9. Other ingredients

[0131] In addition to the above-mentioned components, each ink of the present embodiment may also contain one or more arbitrary components that can be used in conventional inkjet inks. As such arbitrary components, specifically, other additives such as cosolvents, viscosity modifiers, pH modifiers, antioxidants, preservatives, mildew inhibitors, corrosion inhibitors, and chelating agents for capturing metal ions that affect dispersion, and solvents other than the above-mentioned solvents can be listed. These can be used alone or in combination of two or more.

[0132] 2. Recording Method

[0133] The recording method of this embodiment includes an ink attaching step of ejecting the inkjet ink using an inkjet head and attaching it to a recording medium. In the ink attaching step, the nozzle opening time is more than 1 minute, and the nozzle opening time is the time that the part of the nozzle of the inkjet head is open from the time when the ink is ejected from the part of the nozzle to the time when the part of the nozzle is suction-cleaned. In addition, the recording method of this embodiment may include a conveying step or other steps according to other needs.

[0134] 2.1. Ink adhesion process

[0135] In the ink attachment process, the ink is ejected from the inkjet head and attached to the recording medium. More specifically, the pressure generating unit provided in the inkjet head is driven to eject the ink filled in the pressure generating chamber of the inkjet head from the nozzle. Such an ejection method is also called an inkjet method.

[0136] Examples of the inkjet head used in the ink adhesion step include a line head that performs recording by a line method and a serial head that performs recording by a serial method.

[0137] In the line method using a line head, for example, an inkjet head having a width greater than the recording width of a recording medium is fixed to a recording device. Then, the recording medium is moved in a sub-scanning direction (the conveying direction of the recording medium), and ink droplets are ejected from the nozzles of the inkjet head in conjunction with the movement, thereby recording an image on the recording medium.

[0138] In the serial method using a serial head, for example, an inkjet head is mounted on a carriage that can move in the width direction of a recording medium. Then, the carriage is moved in the main scanning direction (the width direction of the recording medium), and ink droplets are ejected from the nozzles of the inkjet head in conjunction with the movement, thereby recording an image on the recording medium.

[0139] In the ink adhesion process of the present embodiment, the time during which a part of the nozzle of the inkjet head is open from the time when the ink is ejected to the time when the part of the nozzle is suction-cleaned, that is, the nozzle open time, is 1 minute or more. Therefore, even in the case where the ink set has a large number of inks and the nozzle open time is 1 minute or more, the present invention is particularly effective.

[0140] 2.2. Conveying process

[0141] In the conveying process, the recording medium is conveyed in a predetermined direction in the recording device. More specifically, the recording medium is conveyed from the paper supply section to the paper discharge section of the recording device using a conveying roller or a conveying belt provided in the recording device. During the conveying process, the ink ejected from the inkjet head adheres to the recording medium to form a recorded object. The conveying can be performed continuously or intermittently.

[0142] 2.3. Recording medium

[0143] The recording medium used in this embodiment is not particularly limited, but examples thereof include absorptive or non-absorptive recording media. Of these, absorptive recording media are prone to problems such as curling, so the present invention, which uses inorganic oxide particles but has excellent clogging recovery properties, is effective.

[0144] There are no particular restrictions on the absorptive recording medium, but examples thereof include ordinary paper such as electronic photographic paper having high permeability to inkjet ink, inkjet paper (inkjet-specific paper having an ink absorbing layer composed of silica particles, alumina particles, or an ink absorbing layer composed of a hydrophilic polymer such as polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP)), coated paper, coated paper, cast-coated paper, etc. that have relatively low permeability to ink and are used for general offset printing, and the like.

[0145] There are no particular restrictions on the non-absorbent recording medium, but examples thereof include films or plates of plastics such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, and polyurethane; plates of metals such as iron, silver, copper, and aluminum; or metal plates or plastic films made by vapor deposition of these various metals, plates of alloys such as stainless steel or brass; recording media formed by bonding (coating) films of plastics such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, and polyurethane onto a paper substrate, etc.

[0146] 3. Recording device

[0147] The recording device according to the present embodiment includes: an inkjet head having nozzles for ejecting inkjet ink toward a recording medium; and a cleaning unit for cleaning the nozzles of the inkjet head.

[0148] As a recording device as an example of this embodiment, Figure 1 A stereogram of the serial printer 1 is shown in FIG. Figure 1 As shown, the serial printer 1 includes a recording unit 13, a platen 5, a drying mechanism 6, a conveying unit 8, a guide rod 9, a linear encoder 10, a control unit CONT, a cover member 11, and a cleaning unit 12. The conveying unit 8 conveys the recording medium M supplied to the serial printer to the recording unit 13, and discharges the recorded recording medium to the outside of the serial printer. Specifically, the conveying unit 8 includes a conveying roller, and conveys the conveyed recording medium M in the secondary scanning directions T1 and T2.

[0149] The recording unit 13 includes an inkjet head 2 for ejecting each ink from an ink cartridge 3 onto a recording medium M conveyed from a conveying unit 8, a carriage 4 for carrying the above structure, and a carriage moving mechanism 7 for moving the carriage 4 along the main scanning directions S1 and S2 of the recording medium M. The ink cartridge is filled with each ink of the ink set.

[0150] The cleaning unit 12 can perform a moisturizing action, a flushing action, an inkjet head cleaning action, and the like. Specifically, the moisturizing action refers to an action of covering the inkjet head 2 with the cap member 11 outside the recording action to suppress the drying of the nozzle holes (not shown) of the inkjet head 2. In addition, the flushing action refers to an action of pre-discharging ink from the nozzle holes of the inkjet head 2 toward the cap member 11 to prevent the nozzle holes from being clogged. The inkjet head cleaning action refers to an action of driving a suction pump (not shown) after covering the inkjet head 2 with the cap member 11 to discharge ink from each nozzle hole while replacing the recording ink or replacement ink in the ink flow path.

[0151] Example

[0152] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples. The present invention is not limited to the following Examples in any way.

[0153] 1. Preparation of each ink in the ink set

[0154] Each component was placed in a container as shown in Table 1, mixed and stirred for 2 hours with a magnetic stirrer, and then dispersed with grinding beads filled with zirconium oxide beads with a diameter of 0.3 mm to fully mix. After stirring for 1 hour, the mixture was filtered using a 5.0 μm PTFE membrane filter to obtain the inks shown in Table 1. The values ​​in Table 1 represent mass %. Water was ion-exchanged water, and was added in such a manner that the mass of each ink was 100 mass %. In addition, in Table 1, the average Hansen SP value of the water-soluble organic solvent represents the weighted average of the Hansen SP values ​​of each water-soluble organic solvent in the ink.

[0155] 2. Preparation of Ink Set

[0156] In addition, by selecting inks so as to achieve the combinations shown in Table 2, each ink set shown in Table 2 was obtained.

[0157] Table 1

[0158]

[0159] The abbreviations used in Table 1 and the ingredients of the products are as follows.

[0160] color material

[0161] ·DB60: Disperse Blue 60

[0162] Compound A: A ) (the compound obtained in the following Preparation Example 1)

[0163] Compound B: B ) (the compound obtained in the following Preparation Example 2)

[0164] ·DB359: Disperse Blue 359

[0165] DB360: Dispersed Blue 360

[0166] DR364: Disperse Red 364

[0167] DR60: Disperse Red 60

[0168] ·DY82: Disperse Yellow 82

[0169] ·DY54: Disperse Yellow 54

[0170] ·DY114: Disperse Yellow 114

[0171] DO25: Disperse Orange 25

[0172] Water-soluble organic solvents

[0173] Propylene glycol

[0174] ·glycerin

[0175] ·2-[2-(2-methoxyethoxy)ethoxy]ethanol

[0176] ·TEGmBE: triethylene glycol monobutyl ether

[0177] Surfactants

[0178] BYK348 = BYK Chemical Japan Ltd., trade name "BYK (registered trademark)-348" (polyether-modified silicone surfactant)

[0179]

Chemical formula 2

[0180]

[0181]

Chemical formula 3

[0182]

[0183] Production Example 1

[0184] According to the above formula (I A The compound represented by ) was prepared as follows.

[0185] 3 parts of 1,4-diamino-2,3-anthraquinone dicarboxylic acid imide and 25 parts of 3-aminopentane were added to 75 parts of cyclopentane to obtain a liquid. The obtained liquid was heated to 140° C. in an autoclave, reacted for 6 hours, and then cooled to room temperature to obtain a liquid. The solid precipitated from the obtained liquid was filtered and separated, washed with 100 parts of methanol and 200 parts of water, and then dried to obtain 3.1 parts of the above formula (I A ) represented by.

[0186] Production Example 2

[0187] According to the above formula (I B The compound represented by ) was prepared as follows.

[0188] 3.0 parts of 1,4-diamino-2,3-anthraquinone dicarboxylic acid imide and 25 parts of 1-aminobutane were added to 75 parts of cyclopentane to obtain a liquid. The obtained liquid was heated to 140° C. in an autoclave, reacted for 6 hours, and then cooled to room temperature to obtain a liquid. The solid precipitated from the obtained liquid was filtered and separated, washed with 100 parts of methanol and 200 parts of water, and then dried to obtain 2.9 parts of the above formula (I B ) represented by.

[0189] 2.1. Determination of SP value by turbidity titration

[0190] The SP value of each ink was measured by a turbidity point titration method using a water / acetone mixed solution having different mixing ratios.

[0191] 2.2. Determination of fluorescent whitening intensity

[0192] B (D65) and B (UVcut) were measured using a spectrophotometer FD-7 (manufactured by Konica Minolta Holdings), and the fluorescent whitening intensity was determined by the following formula: D65 light source refers to a standard light source defined by the International Commission on Illumination.

[0193] Fluorescent whitening intensity ΔB = B(D65)-B(UVcut)……(1)

[0194] (Wherein, B(D65) is the brightness of the D65 light source, and B(UVcut) is the brightness of the D65 light source after cutting off the wavelength below 410nm)

[0195] 3. Evaluation Method

[0196] 3.1. Color reproduction area

[0197] The inkjet printer SureColor SC-F7000 (manufactured by Seiko Epson Corporation) was used to print on TRANSJET Classic (Cham Paper Co., Ltd.) as an intermediate transfer medium at a resolution of 1440×720 dpi and an adhesion weight of 21 g / m 2The color chart was outputted by recording in a manner. Then, the ink-attached side of the intermediate transfer medium was brought into close contact with a cloth (100% polyester, AMINA, manufactured by Toray Industries) as a white recording medium, and heated at 200°C for 60 seconds using a heat press (TP-608M, manufactured by Taiyo Seiki Co., Ltd.) to perform sublimation transfer to obtain each dyed product. The L* value, a* value, and b* value of the obtained reference color chart image were measured using a colorimeter (trade name "FD-7", manufactured by Konica Minolta Holdings). From these values, the value of the L*a*b* color reproduction area volume (color gamut value 1) of each ink group was calculated, and the color reproduction area was evaluated according to the following evaluation criteria.

[0198] Evaluation Benchmarks

[0199] A: Color gamut value 1 is 400,000 or more.

[0200] B: The color gamut value 1 is 350,000 or more and less than 400,000.

[0201] C: The color gamut value 1 is greater than or equal to 300,000 and less than 350,000.

[0202] D: The color gamut value 1 is greater than or equal to 250,000 and less than 300,000.

[0203] E: The color gamut value 1 is less than 250,000.

[0204] 3.2. Fluorescent color reproduction range

[0205] Each dyed product was obtained by the same method as the evaluation test of the color reproduction area described above. The L* value, a* value, b* value, and fluorescent whitening intensity were measured for the obtained reference color chart image using a colorimeter (trade name "FD-7", manufactured by Konica Minolta Holdings). The value of the L*a*b* color reproduction area volume (color gamut value 2) was calculated by plotting points with a fluorescent whitening intensity of 0.3 or more, and the fluorescent color reproduction area was evaluated according to the following evaluation criteria.

[0206] Evaluation Benchmarks

[0207] A: Color gamut value 2 is greater than 200,000.

[0208] B: Color gamut value 2 is greater than or equal to 150,000 and less than 200,000.

[0209] C: Color gamut value 2 is greater than or equal to 100,000 and less than 150,000.

[0210] D: Color gamut value 2 is 50,000 or more and less than 100,000.

[0211] E: Color gamut value 2 is less than 50,000.

[0212] 3.3. Granularity

[0213] Each dyed product was obtained by the same method as the above-mentioned color reproduction area evaluation test. The occupancy rate of the secondary color was changed from 10 to 100%, and the graininess was evaluated visually according to the following evaluation criteria.

[0214] Evaluation Benchmarks

[0215] A: No graininess at all.

[0216] B: Slightly grainy.

[0217] C: Clearly grainy.

[0218] 3.4. Intermittent reliability

[0219] Each ink was filled in an inkjet printer (trade name SC-F10050H, manufactured by Seiko Epson Corporation) and left for 1 minute with the nozzle open. Then, when the ink was ejected without cleaning by the cleaning unit, the number of nozzle drops was counted, and intermittent reliability was evaluated according to the following evaluation criteria.

[0220] Evaluation Benchmarks

[0221] A: The number of nozzles that fell off was 0.

[0222] B: The number of nozzles that have fallen off is 1 to 5.

[0223] C: The number of nozzles that fell off was 6 or more.

[0224] 3.5. Storage stability

[0225] After the ink was left to stand at 70° C. for one week, the initial viscosity and the viscosity after the one-week standing were measured, and the storage stability was evaluated according to the following evaluation criteria.

[0226] Evaluation Benchmarks

[0227] A: Viscosity change is ±5% or less.

[0228] B: The viscosity change is more than ±5% and less than 10%.

[0229] C: The viscosity change is more than ±10% and 15% or less.

[0230] 4. Evaluation results

[0231] Table 2

[0232]

[0233] According to the comparison between Examples 1 to 5 and Comparative Examples 1 to 5, it can be seen that the ink set involved in the present embodiment is superior in color reproduction area, fluorescent color reproduction area, granularity, intermittent reliability and storage stability compared with the ink set involved in Comparative Examples 1 to 5 that do not meet the constituent requirements of the ink component.

Claims

1. An ink set, characterized in that: have: Cyan ink C1, fluorescent whitening intensity is above 3.0, SP value is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 ; Magenta ink M1, fluorescent whitening intensity is above 3.0, SP value is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 ; Yellow ink Y1, fluorescent whitening intensity is above 3.0, SP value is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 ; Cyan ink C2, fluorescent whitening intensity less than 3.0, SP value 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 ; Magenta ink M2, fluorescent whitening intensity less than 3.0, SP value is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 ; as well as Yellow ink Y2, fluorescent whitening intensity less than 3.0, SP value is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 , The SP value is a value obtained by a turbidity point titration method using a water / acetone mixed solution.

2. The ink set according to claim 1, characterized in that: The SP value of the cyan ink C1 is 12 (cal / cm 3 ) 1 / 2 ~14(cal / cm 3 ) 1 / 2 , The SP value of the magenta ink M1 is 12 (cal / cm 3 ) 1 / 2 ~14(cal / cm 3 ) 1 / 2 , The SP value of the yellow ink Y1 is 15 (cal / cm 3 ) 1 / 2 ~17(cal / cm 3 ) 1 / 2 , The SP value of the cyan ink C2 is 14 (cal / cm 3 ) 1 / 2 ~16(cal / cm 3 ) 1 / 2 , The SP value of the magenta ink M2 is 15 (cal / cm 3 ) 1 / 2 ~17(cal / cm 3 ) 1 / 2 , The SP value of the yellow ink Y2 is 12 (cal / cm 3 ) 1 / 2 ~14(cal / cm 3 ) 1 / 2 .

3. The ink set according to claim 1 or 2, characterized in that: The cyan ink C1 contains a compound represented by the following formula (I): In formula (I), R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, the hydrogen atom of the alkyl group may be substituted by an alkoxy group having 1 to 6 carbon atoms, and X represents an oxygen atom or an imino group.

4. The ink set according to claim 1, characterized in that: The yellow ink Y1 contains at least one of Disperse Yellow 232 and Disperse Yellow 82 .

5. The ink set according to claim 1, characterized in that: The magenta ink M1 contains disperse red 364 .

6. The ink set according to claim 1, characterized in that: The SP value obtained by turbidity titration is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 Black ink B.

7. The ink set according to claim 1, characterized in that: The SP value obtained by turbidity titration is 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 Orange ink O.

8. The ink set according to claim 1, wherein: There are more than eight kinds of inks in total. The SP value of all inks obtained by turbidity titration was 12 (cal / cm 3 ) 1 / 2 ~18(cal / cm 3 ) 1 / 2 .

9. The ink set according to claim 1, characterized in that: All inks contain water-soluble organic solvents. The content of the water-soluble organic solvent is 10% by mass or more based on the total amount of each ink.

10. The ink set according to claim 9, characterized in that: The content of the water-soluble organic solvent as a moisturizing agent in each of the cyan ink C1, the magenta ink M1, and the yellow ink Y1 is 12% by mass or more relative to the total amount of each ink.

11. The ink set according to claim 9 or 10, characterized in that: All inks contain water-soluble organic solvents. The average Hansen SP value of the water-soluble organic solvent is 15 (cal / cm 3 ) 1 / 2 The content of the above water-soluble organic solvent is 5% by mass or more based on the total amount of each ink.

12. A recording method, characterized in that: The method comprises the step of ejecting the ink set according to any one of claims 1 to 11 from an inkjet head and attaching the ink set to a recording medium, In the ink adhesion process, the nozzle opening time is more than 1 minute. The nozzle open time is the time during which a part of the nozzle of the inkjet head is open from the time when ink is ejected from the part of the nozzle to the time when the part of the nozzle is suction-cleaned.

13. A recording device, characterized in that: have: An inkjet head having nozzles for ejecting each ink included in the ink set according to any one of claims 1 to 11; and Cleaning unit.

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