Ink set and method for producing printed matter

Abstract

An ink set containing an inkjet ink and a treatment liquid, wherein the inkjet ink contains a pigment, a water-soluble organic solvent, a surfactant and water, the water-soluble organic solvent contains an alkyl diol (A) of 2 to 8 carbon atoms, the weighted average boiling point of the water-soluble organic solvent at one atmosphere is from 175 to 240° C., the surfactant contains an acetylenediol-based surfactant, the treatment liquid contains a coagulant, calcium nitrate is included as the coagulant in an amount of 6.8 to 20.8% by mass relative to the total mass of the treatment liquid, and the pH of the treatment liquid is from 2 to 11.

Claims

1. An ink set comprising an inkjet ink, and a treatment liquid used in combination with the inkjet ink, wherein the inkjet ink comprises a pigment, a water-soluble organic solvent, a surfactant and water, the water-soluble organic solvent comprises an alkyl diol (A) of 2 to 8 carbon atoms, and a weighted average boiling point of the water-soluble organic solvent at one atmosphere is within a range from 175 to 240° C., the surfactant comprises an acetylenediol-based surfactant, the treatment liquid comprises a coagulant, calcium nitrate is included as the coagulant in an amount of 6.8 to 20.8% by mass relative to a total mass of the treatment liquid, and a pH of the treatment liquid is within a range from 2 to 11.

2. The ink set according to claim 1, wherein a pH of the treatment liquid is from 3.5 to 11.

3. The ink set according to claim 1, wherein the treatment liquid further comprises an organic solvent, and the organic solvent comprises less than 10% by mass of organic solvent having a boiling point at one atmosphere of at least 240° C. relative to a total mass of the treatment liquid.

4. The ink set according to claim 1, wherein the inkjet ink further comprises a pigment dispersing resin.

5. The ink set according to claim 4, wherein an acid value of the pigment dispersing resin is within a range from 30 to 300 mgKOH/g.

6. The ink set according to claim 4, wherein an acid value of the pigment dispersing resin is from 100 to 300 mgKOH/g.

7. The ink set according to claim 4, wherein the pigment dispersing resin comprises a water-soluble pigment dispersing resin, and a weight average molecular weight (Mw) of the water-soluble pigment dispersing resin satisfies 10,000≤Mw≤40,000.

8. The ink set according to claim 1, wherein the alkyl diol (A) has 3 to 6 carbon atoms.

9. The ink set according to claim 1, wherein the treatment liquid also comprises a pH adjuster.

10. The ink set according to claim 1, wherein a viscosity of the treatment liquid is within a range from 5 to 100 mPa.Math.s.

11. The ink set according to claim 1, wherein an amount of the calcium nitrate is within a range from 7.0 to 20.5% by mass relative to a total mass of the treatment liquid.

12. A method for producing inkjet ink printed matter that uses the ink set according to claim 1, the method comprising: a step of applying the treatment liquid to a recording medium formed from a paper substrate or a synthetic paper substrate, and a step of applying the inkjet ink by one-pass printing to a portion to which the treatment liquid has been applied.

13. The method for producing inkjet ink printed matter according to claim 12, wherein the step of applying the treatment liquid is conducted so that an amount of calcium ions on a surface of the recording medium is within a range from 0.5 to 5 mmol/m.sup.2.

14. A Printed matter obtained by printing the ink set according to claim 1 to a recording medium.

Description

EXAMPLES

(1) The present invention is described below in further detail using a series of examples and comparative examples. In the following description, unless particularly stated otherwise, “parts” and “%” mean “parts by mass” and “% by mass” respectively.

I. Preparation of Treatment Liquids

(1) Preparation Example for PVA103 Varnish

(2) The materials described below were mixed at room temperature for one hour under constant stirring, and the temperature was then raised to 90° C. and mixing was continued for a further one hour. Subsequently, the thus obtained mixture was cooled to room temperature to obtain a PVA103 varnish.

(3) (Materials)

(4) PVA103 (a polyvinyl alcohol manufactured by Kuraray Co., Ltd. (degree of saponification: 98 to 99% (fully saponified), degree of polymerization: 300)) 25 parts

(5) Ion-exchanged water 75 parts

(2) Preparation Example for Treatment Liquid 1

(6) A mixing container equipped with a stirrer was prepared, and the materials listed below were added sequentially. The materials were mixed at room temperature for one hour under gentle stirring, and the temperature was then raised to 60° C. and mixing was continued for a further one hour. Subsequently, the thus obtained mixture was cooled to room temperature and filtered through a membrane filter having a pore size of 1 μm to obtain a treatment liquid 1.

(7) (Materials)

(8) TABLE-US-00001 Calcium nitrate tetrahydrate (manufactured by 10 parts Yoneyama Chemical Industry Co., Ltd.) Triethanolamine (TEA) 1 part 35% hydrochloric acid (35% HCl) 0.62 parts PVA103 varnish 20 parts 2-propanol (iPrOH) 4 parts Dynol 607 (an acetylene-based surfactant 0.4 parts manufactured by Air Products and Chemicals, Inc.) PROXEL GXL (a preservative, a 1,2-benzisothiazol- 0.05 parts 3-one solution, manufactured by Arch Chemicals, Inc.) Ion-exchanged water 63.93 parts

(9) The viscosity of the obtained treatment liquid 1 at 25° C. was measured using an E-type viscometer (TVE25L viscometer, manufactured by Toki Sangyo Co., Ltd.). Further, the pH of the treatment liquid 1 at 25° C. was measured using a desktop pH meter (F-72 manufactured by Horiba, Ltd.) and a standard ToupH electrode. These results are shown in Table 1.

(3) Preparation Examples for Treatment Liquids 2 to 32

(10) With the exception of using the materials shown in Table 1, the same method as that described for the treatment liquid 1 was used to obtain treatment liquids 2 to 32.

(11) Further, the viscosity and pH of each treatment liquid was measured in the same manner as treatment liquid 1. The measurement results are shown in Table 1.

(12) TABLE-US-00002 TABLE 1 Treatment liquid No. 1 2 3 4 5 6 7 8 Blend Metal salt Ca(NO.sub.3).sub.2•4H.sub.2O 10.0  11.0  20.0  28.0  30.0  20.0  20.0  20.0  amount CaCl.sub.2•2H.sub.2O (%) NaCl pH Base TEA 1.0 1.0 1.0 1.0 1.0 adjuster NaOH Acid 35% HCl  0.62  0.62  0.62  0.62  0.62 0.4 0.3 CH.sub.3COOH 1.0 Other CH.sub.3COONa  0.25 Binder resin PVA103 varnish 20.0  20.0  20.0  20.0  20.0  20.0  20.0  20.0  (solid fraction: 25%) BYK190 (solid fraction: 40%) Organic Monohydric iPrOH 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 solvent alcohol (boiling point: 82° C.) Glycol 1,2-PD (boiling point: 188° C.) 1,2-HexD (boiling point: 224° C.) DEG (boiling point: 244° C.) Other Glycerol (boiling point: 290° C.) Surfactant Dynol 607 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water 63.93 62.93 53.93 45.93 43.93 55.15 55.25 54.3  Treatment liquid viscosity (mPa .Math. s) 8.0 8.2 8.5 8.8 9.0 8.0 8.1 8.2 Treatment liquid pH 6.6 6.5 6.2 5.8 5.5 2.2 3.1 3.6 Calcium nitrate content (%) 6.9 7.6 13.9  19.5  20.8  13.9  13.9  13.9  Amount of organic solvent having boiling 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 point of 240° C. or higher (%) Treatment liquid No. 9 10 11 12 13 14 15 16 Blend Metal salt Ca(NO.sub.3).sub.2•4H.sub.2O 20.0  20.0 20.0  20.0  20.0  20.0  20.0  20.0  amount CaCl.sub.2•2H.sub.2O (%) NaCl pH Base TEA 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 adjuster NaOH Acid 35% HCl 0.6 0.5 0.4  0.62 0.4  0.62  0.62 CH.sub.3COOH Other CH.sub.3COONa Binder resin PVA103 varnish 20.0  20.0  20.0  20.0  20.0  20.0  20.0  20.0  (solid fraction: 25%) BYK190 (solid fraction: 40%) Organic Monohydric iPrOH 4.0 solvent alcohol (boiling point: 82° C.) Glycol 1,2-PD 20.0  (boiling point: 188° C.) 1,2-HexD 15.0  (boiling point: 224° C.) DEG 8.0 10.0  15.0  (boiling point: 244° C.) Other Glycerol 8.0 10.0  (boiling point: 290° C.) Surfactant Dynol 607 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water 54.55 37.95 43.05 50.15 47.93 43.15 49.93 47.93 Treatment liquid viscosity (mPa .Math. s) 8.3 14.0  18.0  15.0  18.0  22.0  18.0  24.0  Treatment liquid pH 8.2 6.6 7.4 7.9 6.2 7.8 6.2 6.2 Calcium nitrate content (%) 13.9  13.9  13.9  13.9  13.9  13.9  13.9  13.9  Amount of organic solvent having boiling 0.0 0.0 0.0 8.0 10.0  15.0  8.0 10.0  point of 240° C. or higher (%) Treatment liquid No. 17 18 19 20 21 22 23 24 Blend Metal salt Ca(NO.sub.3).sub.2•4H.sub.2O 20.0  20.0  20.0  20.0  20.0  20.0  20.0  20.0  amount CaCl.sub.2•2H.sub.2O (%) NaCl pH Base TEA 1.0 1.0 1.0 1.0 1.0 adjuster NaOH 0.5 Acid 35% HCl  0.62 0.4  0.62  0.62  0.62  0.62 CH.sub.3COOH Other CH.sub.3COONa Binder resin PVA103 varnish 20.0  20.0  20.0  20.0  20.0  64.0  (solid fraction: 25%) BYK190 10.0  12.5  (solid fraction: 40%) Organic Monohydric iPrOH 4.0 4.0 4.0 solvent alcohol (boiling point: 82° C.) Glycol 1,2-PD 10.0  30.0  20.0  (boiling point: 188° C.) 1,2-HexD 10.0  (boiling point: 224° C.) DEG (boiling point: 244° C.) Other DEGBE (boiling point: 230° C.) Glycerol 15.0  (boiling point: 290° C.) Surfactant Dynol 607 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 EMULGEN 120 Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water 42.93 54.65 33.93 25.55 39.55 67.93 65.43 13.93 Treatment liquid viscosity (mPa .Math. s) 32.0  8.5 17.0  17.0  17.0  4.5 5.0 100.0  Treatment liquid pH 6.2 10.3  6.2 5.0 5.0 6.0 6.0 5.5 Calcium nitrate content (%) 13.9  13.9  13.9  13.9  13.9  13.9   13.9  13.9  Amount of organic solvent having boiling 15.0  0.0 0.0 0.0 0.0 0.0 0.0 0.0 point of 240° C. or higher (%) Treatment liquid No. 25 26 27 28 29 30 31 32 Blend Metal salt Ca(NO.sub.3).sub.2•4H.sub.2O 20.0  17.3  7.8 31.8  20.0  20.0  amount CaCl.sub.2•2H.sub.2O 15.0  (%) NaCl 20.0  pH Base TEA 1.0 1.0 1.0 1.0 1.0 adjuster NaOH 0.5 Acid 35% HCl  0.62  0.62  0.62  0.62  0.62  0.62 CH.sub.3COOH Other CH.sub.3COONa Binder resin PVA103 varnish 76.0  20.0  20.0  20.0  20.0  20.0  20.0  (solid fraction: 25%) BYK190 (solid fraction: 40%) Organic Monohydric iPrOH 4.0 4.0 4.0 4.0 4.0 4.0 solvent alcohol (boiling point: 82° C.) Glycol 1,2-PD (boiling point: 188° C.) 1,2-HexD (boiling point: 224° C.) DEG (boiling point: 244° C.) Other DEGBE 15.0  (boiling point: 230° C.) Glycerol 30.0  (boiling point: 290° C.) Surfactant Dynol 607 0.4 0.4 0.4 0.4 0.4 0.4 0.4 EMULGEN 120 1 Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water  1.93 36.65 58.93 53.93 66.13 42.13 54.93 55.05 Treatment liquid viscosity (mPa .Math. s) 120.0  10.2  8.0 8.5 8.0 9.0 8.2 8.1 Treatment liquid pH 5.6 8.0 6.5 6.2 6.6 5.5 1.7 11.5  Calcium nitrate content (%) 13.9  12.0  0.0 0.0 5.4 22.1  13.9  13.9  Amount of organic solvent having boiling 0.0 30.0  0.0 0.0 0.0 0.0 0.0 0.0 point of 240° C. or higher (%)

(13) Details regarding the abbreviations and product names for the materials shown in Table 1 are as follows.

(14) <1> Metal Salts

(15) Ca(NO.sub.3).sub.2.4H.sub.2O: calcium nitrate tetrahydrate CaCl.sub.2.2H.sub.2O: calcium chloride dihydrate NaCl: sodium chloride <2> pH Adjusters TEA: triethanolamine NaOH: sodium hydroxide 35% HCl: 35% hydrochloric acid CH.sub.3COOH: acetic acid CH.sub.3COONa: sodium acetate
<3> Binder Resins PVA103 varnish: as described above BYK190: an aqueous solution of a styrene-maleic acid resin (solid fraction: 40%) manufactured by BYK-Chemie Japan K.K.
<4> Organic Solvents iPrOH: 2-propanol 1,2-PD: 1,2-propanediol 1,2-HexD: 1,2-hexanediol DEG: diethylene glycol DEGBE: diethylene glycol monobutyl ether
<5> Surfactants Dynol 607: an acetylene-based surfactant manufactured by Air Products and Chemicals, Inc.) EMULGEN 120: polyoxyethylene lauryl ether manufactured by Kao Corporation
<6> Additive (Preservative) PROXEL GXL: a 1,2-benzisothiazol-3-one solution, manufactured by Arch Chemicals, Inc.

II. Preparation of Inkjet Inks

(1) Pigment Dispersing Resin

(16) <Production Example for Aqueous Solution of Pigment Dispersing Resin 1>

(17) A reaction container fitted with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 93.4 parts of butanol, and the container was flushed with nitrogen gas. Subsequently, the contents of the reaction container were heated to 110° C., and a mixture containing 20 parts of styrene, 40 parts of acrylic acid and 40 parts of behenyl acrylate as polymerizable monomers and 6 parts of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to the container over a period of two hours to achieve a polymerization reaction. Following completion of the dropwise addition, reaction was continued at 110° C. for a further three hours, an additional 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was continued at 110° C. for a further one hour, thus obtaining a solution of a pigment dispersing resin 1.

(18) Following cooling of the solution of the pigment dispersing resin 1 to room temperature, 37.1 parts of dimethylaminoethanol was added to neutralize the solution, and 100 parts of water was then added to generate an aqueous solution of a pigment dispersing resin (water-soluble pigment dispersing resin) 1. Subsequently, the aqueous solution was heated to at least 100° C., and the butanol was removed by azeotropic distillation with the water to adjust the solid fraction to 30%. This yielded an aqueous solution of the pigment dispersing resin 1 with a solid fraction of 30%. The above term “aqueous solution” describes a solution containing an aqueous medium, and components dispersed and/or dissolved in the aqueous medium.

(19) Measurement of the pH of the aqueous solution (solid fraction: 30%) of the above pigment dispersing resin 1 using a desktop pH meter F-72 manufactured by Horiba, Ltd. revealed a pH of 9.7. Further, the acid value of the pigment dispersing resin 1 measured using the method described above was 250 mgKOH/g, and the weight average molecular weight was 22,500.

(20) <Production Examples for Aqueous Solutions of Pigment Dispersing Resins 2 to 7>

(21) With the exceptions of altering the types and blend amounts of the polymerizable monomers and the amount of the polymerization initiator as shown below in Table 2, aqueous solutions (solid fraction: 30%) of pigment dispersing resins (water-soluble pigment dispersing resins) 2 to 7 were obtained in the same manner as the pigment dispersing resin 1.

(22) TABLE-US-00003 TABLE 2 Pigment dispersing resin 1 2 3 4 5 6 7 Polymerizable Styrene    20      20      30      35      45      20      20   monomers Acrylic acid    40      30      16      6      1      50      30   Lauryl methacrylate    50      44      59      54      30      50   Behenyl acrylate    40   Polymerization V-601    6      6      6      6      6      6      12   initiator Aqueous solution pH    9.7    8.1    8.5    8.8    9.2    7.4    8.1 Acid value (mgKOH/g)   250     200     110      40      15     350     200   Weight average molecular weight 22,500   15,000   13,000   11,000   15,000   28,000   8,000 

(23) Table 2 shows the pH of the aqueous solution (solid fraction: 30%) of each pigment dispersing resin, the acid value of each pigment dispersing resin, and the weight average molecular weight of each pigment dispersing resin.

(24) <Production Example for Aqueous Solution of Joncryl 678>

(25) A mixing container was charged sequentially with 4.0 parts of Joncryl 678 (a styrene-acrylic resin manufactured by BASF Corporation, acid value: 215 mgKOH/g, weight average molecular weight: 8,500), 1.7 parts of dimethylaminoethanol and 94.3 parts of water, and by mixing the components thoroughly under heating at 70° C. to dissolve the resin, an aqueous solution (solid fraction: 4%) of Joncryl 678 was obtained.

(2) Pigment Dispersions

(26) <Preparation Examples for Cyan Pigment Dispersions 1 to 7>

(27) Twenty parts of LIONOL BLUE 7358G (C.I. Pigment Blue 15:3) manufactured by Toyo Color Co., Ltd., 20 parts of the aqueous solution (solid fraction: 30%) of the pigment dispersing resin 1 and 60 parts of water were mixed together and preliminary dispersed using a stirrer. Subsequently, the mixture was subjected to a main dispersion for two hours using a Dyno-Mill with a capacity of 0.6 L filled with 1,800 g of zirconia beads of diameter 0.5 mm, thus obtaining a cyan pigment dispersion 1. Further, with the exception of replacing the pigment dispersing resin 1 with each of the pigment dispersing resins 2 to 7, cyan pigment dispersions 2 to 7 were obtained in the same manner as the above cyan pigment dispersion 1.

(28) <Preparation Examples for Magenta Pigment Dispersions 1 to 7>

(29) With the exception of changing the pigment used to Inkjet Magenta E5B02 (C.I. Pigment Violet 19) manufactured by Clariant AG, magenta pigment dispersions 1 to 7 were obtained in the same manner as the preparation examples for the above cyan pigment dispersions 1 to 7.

(30) <Preparation Examples for Yellow Pigment Dispersions 1 to 7>

(31) With the exception of changing the pigment used to LIONOL YELLOW TT-1405G (C.I. Pigment Yellow 14) manufactured by Toyo Color Co., Ltd., yellow pigment dispersions 1 to 7 were obtained in the same manner as the preparation examples for the above cyan pigment dispersions 1 to 7.

(32) <Preparation Examples for Black Pigment Dispersions 1 to 7>

(33) With the exception of changing the pigment used to PrinteX 85 (carbon black) manufactured by Orion Engineered Carbons S.A., black pigment dispersions 1 to 7 were obtained in the same manner as the preparation examples for the above cyan pigment dispersions 1 to 7.

(34) <Preparation Example for Cyan Pigment Dispersion 8>

(35) Twenty parts of LIONOL BLUE 7358G (C.I. Pigment Blue 15:3) manufactured by Toyo Color Co., Ltd., 24 parts of Plascoat Z-730 (a carboxyl group-containing polyester resin manufactured by GOO Chemical Co., Ltd., weight average molecular weight: 3,000, acid value: 50 mgKOH/g, solid fraction concentration: 25%) and 56 parts of water were mixed together and preliminary dispersed using a stirrer. Subsequently, the mixture was subjected to a main dispersion for two hours using a Dyno-Mill with a capacity of 0.6 L filled with 1,800 g of zirconia beads of diameter 0.5 mm, thus obtaining a cyan pigment dispersion 8.

(36) <Preparation Examples for Magenta Pigment Dispersion 8, Yellow Pigment Dispersion 8 and Black Pigment Dispersion 8>

(37) With the exception of changing the pigment used to Inkjet Magenta E5B02 (C.I. Pigment Violet 19) manufactured by Clariant AG, LIONOL YELLOW TT-1405G (C.I. Pigment Yellow 14) manufactured by Toyo Color Co., Ltd., and PrinteX 85 (carbon black) manufactured by Orion Engineered Carbons S.A. respectively, a magenta pigment dispersion 8, yellow pigment dispersion 8 and black pigment dispersion 8 were obtained in the same manner as the preparation example for the above cyan pigment dispersion 8.

(38) <Preparation Example for Cyan Pigment Dispersion 9>

(39) A mixing container was charged sequentially with 75.0 parts of the aqueous solution of Joncryl 678 produced above and 10.0 parts of water, and the components were mixed thoroughly. Subsequently, 15 parts of C.I. Pigment Blue 15:3 was added and stirred thoroughly. A main dispersion was then conducted in the same manner as that described above for the cyan pigment dispersion 1 using a Dyno-Mill with a capacity of 0.6 L, thus obtaining a cyan pigment dispersion 9 (pigment concentration: 15%).

(40) <Preparation Examples for Magenta Pigment Dispersion 9, Yellow Pigment Dispersion 9 and Black Pigment Dispersion 9>

(41) With the exception of changing the C.I. Pigment Blue 15:3 to Inkjet Magenta E5B02 (C.I. Pigment Violet 19) manufactured by Clariant AG, LIONOL YELLOW TT-1405G (C.I. Pigment Yellow 14) manufactured by Toyo Color Co., Ltd., and PrinteX 85 (carbon black) manufactured by Orion Engineered Carbons S.A. respectively, a magenta pigment dispersion 9, yellow pigment dispersion 9 and black pigment dispersion 9 (each having a pigment concentration of 15%) were obtained in the same manner as the preparation example for the above cyan pigment dispersion 9.

(3) Inkjet Ink Sets

(42) <Production Example for CMYK Inkjet Ink Set 1>

(43) The materials listed below were added sequentially to a mixing container under constant stirring with a stirrer, and were mixed thoroughly until a uniform mixture was obtained. Subsequently, a filtration was performed using a membrane filter having a pore size of 1 μm to remove coarse particles that can cause inkjet head blockages, thus obtaining an ink. More specifically, by conducting the above step with each of the previously prepared cyan pigment dispersion 1, magenta pigment dispersion 1, yellow pigment dispersion 1 and black pigment dispersion 1, a cyan ink, magenta ink, yellow ink and black ink were obtained. Using these four color inks, a CMYK inkjet ink set 1 was produced.

(44) (Materials)

(45) TABLE-US-00004 Pigment dispersion 1 30 parts (each of the previously prepared pigment dispersions 1 of cyan, magenta, yellow and black Joncryl 8211 (an acrylic resin emulsion 13 parts manufactured by BASF Corporation, solid fraction: 44%, acid value: 26 mgKOH/g) 1,2-propanediol 17 parts 1,3-propanediol 10 parts Triethanolamine 0.5 parts Surfynol 465 (an acetylene-based 1 part surfactant manufactured by Air Products and Chemicals, Inc.) PROXEL GXL 0.05 parts Ion-exchanged water 28.45 parts

(46) The viscosity of each of the obtained inks at 25° C. was measured using an E-type viscometer (TVE25L viscometer, manufactured by Toki Sangyo Co., Ltd.). The average value of the viscosities of the cyan ink, magenta ink, yellow ink and black ink that constitute the above CMYK inkjet ink set 1 is shown in Table 3.

(47) Further, the weighted average boiling point for the water-soluble organic solvent shown in Table 3 represents the value for the weighted average boiling point at one atmosphere. This weighted average boiling point is a value obtained by calculating, for each water-soluble organic solvent, a multiplication value of the boiling point at one atmosphere and the mass ratio of that organic solvent relative to the total mass of all of the water-soluble organic solvents, and then adding together the calculated multiplication values for the various water-soluble organic solvents.

(48) <Production Examples for CMYK Inkjet Ink Sets 2 to 34>

(49) With the exception of using the materials shown below in Table 3, the same method as that described for the inkjet ink set 1 was used to obtain CMYK inkjet ink sets 2 to 34 (each composed of the four colors of C, M, Y, K). For each of these inkjet ink sets, the viscosity was measured and the weighted average boiling point of the water-soluble organic solvents at one atmosphere was determined in the same manner as described for the inkjet ink set 1. These results are shown in Table 3.

(50) TABLE-US-00005 TABLE 3 CMYK inkjet ink set 1 2 3 4 5 6 7 8 9 10 Blend Pigment Pigment 30.0 30.0 amount dispersion dispersion 1 (%) Pigment 30.0 dispersion 2 Pigment 30.0 dispersion 3 Pigment 30.0 dispersion 4 Pigment 30.0 dispersion 5 Pigment 30.0 dispersion 6 Pigment 30.0 dispersion 7 Pigment 30.0 dispersion 8 Pigment self- CABOJET 60.0 dispersion Binder resin Joncryl 8211 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 (solid fraction: 44%) Water- Diol (A) EG soluble (boiling point: organic 198° C.) solvent 1,2-PD 17.0 17.0 17.0 17.0 17.0 17.0 17.0 17.0 16.0 17.0 (boiling point: 188° C.) 1,3-PD 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0  9.0 (boiling point: 214° C.) 1,2-BuD (boiling point: 194° C.) 1,2-HexD (boiling point: 223° C.) 3-M-1,5-PenD (boiling point: 250° C.) Diethylene DEG 10.0 glycol (boiling point: 244° C.) Alkyl Glycerol polyol (boiling point: 290° C.) pH adjuster TEA  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5  0.5 NaOH  0.1 Surfac- acetylene- Surfynol 465  1.0  1.0  1.0  1.0  1.0  1.0  1.0  1.0  1.0  1.0 tant based Surfynol 104E Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water  28.45  28.45  28.45  28.45  28.45  28.45  28.45  28.45  0.45  28.85 Viscosity  8.0  7.7  7.5  7.4  7.9  8.3  7.1  7.3  7.4  9.5 Amount of organic solvent having  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0  0.0 10.0 boiling point of 240° C. or higher (%) Weighted average boiling point of 197.6  197.6  197.6  197.6  197.6  197.6  197.6  197.6  197.4  208.7  water-soluble organic solvents (° C.) CMYK inkjet ink set 11 12 13 14 15 16 17 18 19 Blend Pigment Pigment 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 amount dispersion dispersion 1 (%) Pigment dispersion 2 Pigment dispersion 3 Pigment dispersion 4 Pigment dispersion 5 Pigment dispersion 6 Pigment dispersion 7 Pigment dispersion 8 Pigment self- CABOJET dispersion Binder resin Joncryl 8211 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 13.0 (solid fraction: 44%) Water- Diol (A) EG 17.0 soluble (boiling point: organic 198° C.) solvent 1,2-PD  5.0  4.0 15.0 17.0 (boiling point: 188° C.) 1,3-PD  2.0 17.0 (boiling point: 214° C.) 1,2-BuD 17.0 10.0 (boiling point: 194° C.) 1,2-HexD 17.0 10.0 (boiling point: 223° C.) 3-M-1,5-PenD 17.0 (boiling point: 250° C.) Diethylene DEG 15.0 17.0 10.0 glycol (boiling point: 244° C.) Alkyl Glycerol 10.0 15.0 10.0 polyol (boiling point: 290° C.) pH adjuster TEA  1.0  1.0  1.0  1.0 NaOH  0.1  0.1  0.1  0.1  0.1 Surfac- acetylene- Surfynol 465  1.0  1.0  1.0  1.0  1.0  0.5 tant based Surfynol 104E  1.0  1.0  0.5 Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water  28.85  23.85  23.85  21.85  40.85  38.95  39.95  28.45  28.45 Viscosity 12.0  8.2 10.0 12.0 10.1  7.8  7.3  7.4  7.8 Amount of organic solvent having 10.0 15.0 15.0 34.0 10.0 10.0  0.0  0.0  0.0 boiling point of 240° C. or higher (%) Weighted average boiling point of 232.1  239.0  232.8  247.0  225.3  255.0  188.0  190.2  217.3  water-soluble organic solvents (° C.) CMYK inkjet ink set 20 21 22 23 24 25 26 27 28 29 Blend Pigment Pigment 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 amount dispersion dispersion 1 (%) Pigment dispersion 9 Binder resin Joncryl 8211 13.0 13.0 13.0 13.0 13.0 (solid fraction: 44%) X-345 12.0 12.0 12.0 12.0 12.0 (solid fraction: 37%) JDX6500 (solid fraction: 29.5%) Water- Diol (A) 1,2-PD  8.5  3.5  1.0  3.0  3.0  3.0  3.0  3.0 soluble (boiling point: organic 188° C.) solvent 1,3-PD 10.0 10.0 10.0 10.0 10.0 (boiling point: 214° C.) 1,2-HexD  5.0  5.0  5.0  5.0  5.0 (boiling point: 223° C.) 3-M-1,5-PenD  8.5 13.5 16.0 17.0 17.0 (boiling point: 250° C.) Diethylene DEG 10.0 10.0 10.0 10.0 10.0 10.0 glycol (boiling point: 244° C.) Alkyl Glycerol 10.0 polyol (boiling point: 290° C.) Glycol TEGBE ether (boiling point: 278° C.) DEGME 10.0 (boiling point: 194° C.) PGME 10.0 (boiling point: 121° C.) Monohydric 3MB 10.0 alcohol (boiling point: 158° C.) pH adjuster TEA  1.0  1.0  1.0  1.0  1.0 NaOH  0.1  0.1  0.1  0.1  0.1 Surfac- Acetylene- Surfynol 465  1.0  1.0  1.0  1.0 tant based Surfynol 104E  1.0  1.0  1.0  1.0  1.0  1.0 Siloxane- BYK348 based Fluorine- Zonyl FS-300 based Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05  0.05 Water  28.85  28.85  28.85  28.85  28.85  27.95  27.95  27.95  27.95  27.95 Viscosity  9.7  9.9 10.0 10.2 10.0  8.4  8.3  8.0  7.9  7.7 Amount of organic solvent having 18.5 23.5 26.0 27.0 27.0 10.0 10.0  0.0  0.0  0.0 boiling point of 240° C. or higher (%) Weighted average boiling point of 228.3  239.7  245.5  247.8  247.8  219.4  205.2  189.6  178.4  167.0  water-soluble organic solvents (° C.) CMYK inkjet ink set 30 31 32 33 34 Blend Pigment Pigment 30.0 30.0 30.0 30.0 amount dispersion dispersion 1 (%) Pigment 33.0 dispersion 9 Binder resin Joncryl 8211 13.0 13.0 13.0 (solid fraction: 44%) X-345 (solid fraction: 37%) JDX6500 15.0 10.0 (solid fraction: 29.5%) Water- Diol (A) 1,2-PD 11.5 15.0 17.0 17.0 soluble (boiling point: organic 188° C.) solvent 1,3-PD 10.0 10.0 (boiling point: 214° C.) 1,2-HexD (boiling point: 223° C.) 3-M-1,5-PenD (boiling point: 250° C.) Diethylene DEG 10.0 glycol (boiling point: 244° C.) Alkyl Glycerol 25.0 17.0 polyol (boiling point: 290° C.) Glycol TEGBE  5.0 ether (boiling point: 278° C.) DEGME  3.0 (boiling point: 194° C.) PGME (boiling point: 121° C.) Monohydric 3MB alcohol (boiling point: 158° C.) pH adjuster TEA  1.0  0.5  0.5  0.5 NaOH Surfac- Acetylene- Surfynol 465  0.5  1.0 tant based Surfynol 104E  1.0 Siloxane- BYK348  1.0 based Fluorine- Zonyl FS-300  1.0 based Preservative PROXEL GXL  0.05  0.05  0.05  0.05  0.05 Water  38.45  11.45  28.45  28.45  28.45 Viscosity  7.5 10.0 13.8  7.9  7.9 Amount of organic solvent having  0.0 30.0 27.0  0.0  0.0 boiling point of 240° C. or higher (%) Weighted average boiling point of 189.2  254.7  273.0  197.6  197.6  water-soluble organic solvents (° C.)

(51) Of the materials shown in Table 3, details regarding the materials and abbreviations not used in Table 1 or the above description are as follows.

(52) <Pigment Dispersions>

(53) CABOJET: Cyan: Cabojet 250C (a self-dispersing copper phthalocyanine pigment dispersion, manufactured by Cabot Corporation, pigment concentration: 10%) Magenta: Cabojet 265M (a self-dispersing magenta pigment dispersion, manufactured by Cabot Corporation, pigment concentration: 10%) Yellow: Cabojet 270 (a self-dispersing yellow pigment dispersion, manufactured by Cabot Corporation, pigment concentration: 10%) Black: Cabojet 200 (a self-dispersing carbon black aqueous solution, manufactured by Cabot Corporation, pigment concentration: 20%) was diluted with an equal volume of water to adjust the pigment concentration to 10% X-345: Hiros X-345 (a styrene-acrylic water-soluble resin solution, manufactured by BASF Corporation, solid fraction: 37% (and containing 35% of 2-propanol), acid value: 40 mgKOH/g) JDX6500: Joncryl JDX6500 (a styrene-acrylic water-soluble resin solution, manufactured by BASF Corporation, solid fraction: 29.5%, acid value: 74 mgKOH/g)
<Water-Soluble Organic Solvents> EG: ethylene glycol 1,2-PD: 1,2-propanediol 1,3-PD: 1,3-propanediol 1,2-BuD: 1,2-butanediol 1,2-HexD: 1,2-hexanediol 3-M-1,5-PenD: 3-methyl-1,5-pentanediol TEGBE: triethylene glycol monobutyl ether DEGME: diethylene glycol monomethyl ether PGME: propylene glycol monomethyl ether 3 MB: 3-methoxy-1-butanol
<Surfactants> Surfynol 104E: an acetylene-based surfactant manufactured by Air Products and Chemicals, Inc. BYK348: a siloxane-based surfactant manufactured by BYK-Chemie Japan K.K. Zonyl FS-300: a fluorine-based surfactant manufactured by E. I. du Pont de Nemours and Company.

III. Evaluations of Treatment Liquids and Inkjet Inks

(1) Production Examples for Recording Media with Applied Treatment Liquid

(54) <Production Example for Recording Medium 1a with Applied Treatment Liquid>

(55) Using a print tester Flexiproof 100 (manufactured by Matsuo Sangyo Co., Ltd.), the treatment liquid 1 prepared in the manner described above was coated uniformly onto OK Top Coat+paper (manufactured by Oji Holdings Corporation, grammage: 104.7 g/m.sup.2, referred to as “recording medium A” in the subsequent description and Tables 4 to 6). The coating was performed using a ceramic roller having 140 ridges/inch at a speed of 80 m/min, so as to achieve a coating film thickness of the treatment liquid 1 of 3.0±0.3 μm. Following application of the treatment liquid 1 in the manner described above, the OK Top Coat+paper was dried for three minutes in a 50° C. air oven, thus completing production of a recording medium 1a with the applied treatment liquid.

(56) <Production Examples for Recording Media 2a to 26a and 33a to 38a with Applied Treatment Liquids>

(57) Using the same method as the recording medium 1a with the applied treatment liquid, recording media 2a to 26a and 33a to 38a each with an applied treatment liquid were produced using the treatment liquids shown in Table 4.

(58) <Production Example for Recording Medium 27a with Applied Treatment Liquid>

(59) With the exceptions of using the treatment liquid 3 prepared above, and using the print tester Flexiproof 100 with a ceramic roller having 1,000 ridges/inch so as to achieve a coating film thickness of the treatment liquid 3 of 0.4±0.1 μm, a recording medium 27a with an applied treatment liquid was produced in the same manner as the recording medium 1a with an applied treatment liquid.

(60) <Production Example for Recording Medium 28a with Applied Treatment Liquid>

(61) Following production of the recording medium 3a with an applied treatment liquid, a print tester Flexiproof 100 with a ceramic roller having 140 ridges/inch was used to apply a second coating of the treatment liquid 3 to the surface already coated with the treatment liquid 3, and the recording medium was then dried for three minutes in a 50° C. air oven. This process was repeated a further two times to produce a recording medium 28a with an applied treatment liquid in which the total wet coating film thickness of the treatment liquid 3 was 12.0±1.2 μm.

(62) <Production Examples for Recording Media 29a to 31a and 39a with Applied Treatment Liquids>

(63) With the exceptions of using the treatment liquids 2 to 4 and 27, and using Npi high-quality paper 45 (manufactured by Nippon Paper Industries Co., Ltd., grammage: 52.3 g/m.sup.2, referred to as “recording medium B” in the subsequent description and Tables 4 to 6) as the recording medium, recording media 29a to 31a and 39a with applied treatment liquids were produced in the same manner as the recording medium 1a with an applied treatment liquid.

(64) <Production Example for Recording Medium 32a with Applied Treatment Liquid>

(65) With the exception of using the treatment liquid 3 and using a 100% cotton white cloth (referred to as “recording medium C” in the subsequent description and Tables 4 to 6) as the recording medium, a recording medium 32a with an applied treatment liquid was produced in the same manner as the recording medium 1a with an applied treatment liquid.

(66) TABLE-US-00006 TABLE 4 Recording medium Amount of calcium with applied Coating film ions on recording treatment Treatment Recording thickness medium surface liquid liquid No. medium (μm) (mmol/m.sup.2)  1a 1 A 3.0 2.5  2a 2 A 3.0 2.5  3a 3 A 3.0 2.5  4a 4 A 3.0 2.5  5a 5 A 3.0 2.5  6a 6 A 3.0 2.5  7a 7 A 3.0 2.5  8a 8 A 3.0 2.5  9a 9 A 3.0 2.5 10a 10 A 3.0 2.5 11a 11 A 3.0 2.5 12a 12 A 3.0 2.5 13a 13 A 3.0 2.5 14a 14 A 3.0 2.5 15a 15 A 3.0 2.5 16a 16 A 3.0 2.5 17a 17 A 3.0 2.5 18a 18 A 3.0 2.5 19a 19 A 3.0 2.5 20a 20 A 3.0 2.5 21a 21 A 3.0 2.5 22a 22 A 3.0 2.5 23a 23 A 3.0 2.5 24a 24 A 3.0 2.5 25a 25 A 3.0 2.5 26a 26 A 3.0 2.5 27a 3 A 0.4 0.3 28a 3 A 12.0 10.2 29a 2 B 3.0 2.5 30a 3 B 3.0 2.5 31a 4 B 3.0 2.5 32a 3 C 3.0 2.5 33a 27 A 3.0 2.1 34a 28 A 3.0 0.0 35a 29 A 3.0 4.0 36a 30 A 3.0 10.0 37a 31 A 3.0 2.5 38a 32 A 3.0 2.5 39a 27 B 3.0 2.1

(2) Evaluation of Treatment Liquid Coating Irregularities

(67) <Evaluation of Treatment liquid Coating Irregularities (Initial)>

(68) In order to enhance the visibility, 0.1 g of Kayafect Red P Liquid (manufactured by Nippon Kayaku Co., Ltd.) was added to 9.9 g samples of each of the treatment liquids 1 to 26 produced above. These samples were then each mixed thoroughly to dissolve the dye, thus obtaining colored treatment liquids 1 to 26. Using a Flexiproof 100 (manufactured by Matsuo Sangyo Co., Ltd.), each of these colored treatment liquids was coated uniformly onto the recording medium shown below in Table 5. The coating of the colored treatment liquid was performed using a ceramic roller having 140 ridges/inch at a speed of 80 m/min, so as to achieve a coating film thickness of the treatment liquid 1 of 3.0±0.3 μm. Following application of the treatment liquid, the recording medium was dried for three minutes in a 50° C. air oven, thus completing production of a recording media 1b to 30b each with an applied colored treatment liquid.

(69) The level of treatment liquid coating irregularities (the initial coating applicability) was evaluated by continuously producing 10 copies of each recording medium with an applied colored treatment liquid using the method described above, and visually inspecting each recording medium for color irregularities. The evaluation criteria were as follows, with evaluations of A and B being deemed a good level of coating irregularities for the treatment liquid.

(70) (Evaluation criteria)

(71) A: absolutely no coating irregularities observed in any of the 10 copies. B: coating irregularities observed in one or two of the 10 copies. C: coating irregularities observed in at least three of the 10 copies.
<Evaluation of Treatment liquid Coating Irregularities (after Aging)>

(72) Ten kg of each of the above treatment liquids 1 to 26 was placed in an 18-liter drum, and with the drum unsealed in an open state, the drum was left to stand for one week at room temperature. Subsequently, the solid fraction concentration of each treatment liquid was measured, and if the measured value was greater than that prior to the standing period, then water was added to adjust the solid fraction concentration to the same as that prior to standing, thus completing preparation of aged treatment liquids 1 to 26.

(73) Using the above aged treatment liquids 1 to 26, aged colored treatment liquids 1 to 26 were prepared using the same method as that described above in the evaluation method for treatment liquid coating irregularities. Recording media 1c to 30c with these applied aged colored treatment liquids were then produced, and the level of treatment liquid coating irregularities after aging (the coating applicability after aging) was evaluated. The same evaluation criteria as those described above were used.

(74) The evaluation results for the above coating irregularities are shown in Table 5.

(75) TABLE-US-00007 TABLE 5 Recording Recording medium medium with applied with applied colored aged colored Treatment liquid treatment treatment Treatment Recording coating irregularities liquid liquid liquid No. medium Initial After aging  1b  1c 1 A A A  2b  2c 2 A A A  3b  3c 3 A A A  4b  4c 4 A A A  5b  5c 5 A A A  6b  6c 6 A A B  7b  7c 7 A A B  8b  8c 8 A A B  9b  9c 9 A A B 10b 10c 10 A A A 11b 11c 11 A A A 12b 12c 12 A A A 13b 13c 13 A A A 14b 14c 14 A A A 15b 15c 15 A A A 16b 16c 16 A A A 17b 17c 17 A A A 18b 18c 18 A A A 19b 19c 19 A A A 20b 20c 20 A A A 21b 21c 21 A A A 22b 22c 22 A B B 23b 23c 23 A A A 24b 24c 24 A A A 25b 25c 25 A B B 26b 26c 26 A A B 27b 27c 2 B A A 28b 28c 3 B A A 29b 29c 4 B A A 30b 30c 3 C A A

IV. Evaluation of Ink Sets

Examples 1 to 61, Comparative Examples 1 to 11

(1) Preparation of Inkjet Ink Set Printing Apparatus

(76) Four inkjet heads KJ4B-1200 (manufactured by Kyocera Corporation) were installed above a conveyor capable of transporting a recording medium, and the K, C, M and Y inkjet inks that constitute an inkjet ink set were used to fill these heads in sequence from the upstream side. The design resolution of these inkjet heads is 1,200 dpi, the maximum drive frequency is 64 kHz, and the recording resolution in the recording medium transport direction during printing at the maximum drive frequency and a printing speed of 80 m/min is 1,200 dpi.

(2) Production of Printed Matter

(77) <Printing of Printed Matter for Evaluating Aggregation Properties (Color Mixing)>

(78) Each of the recording media with an applied treatment liquid produced in the manner described above was secured to the conveyor of the aforementioned inkjet ink set printing apparatus, and the conveyor was driven at a fixed speed listed below. On the other hand, as the recording medium with the applied treatment liquid passed beneath the installed location of the inkjet heads, the inkjet inks were jetted onto the recording medium in KCMY order using a drop volume of 3 pL to print a natural image N5 (bicycle) from the high-precision color digital standard image data (CMYK/SCID) prescribed in JIS X 9201. Within 10 seconds of the completion of printing, the printed matter was fed into a 50° C. air oven and dried for three minutes, thus obtaining printed matter for evaluating bleeding. The above conveyor speed was set to one of three speeds: 40 m/min, 60 m/min and 80 m/min, with printing conducted under each of these conditions to obtain printed matter. For a portion of the ink sets described below, the same printing was also conducted at a conveyor speed of 100 m/min.

(79) <Printing of Solid Printed Matter>

(80) Each of the recording media with an applied treatment liquid produced in the manner described above was secured to the conveyor of the aforementioned inkjet ink set printing apparatus, and the conveyor was driven at a fixed speed listed below. On the other hand, as the recording medium with the applied treatment liquid passed beneath the installed location of the inkjet heads, the KCMY inkjet inks were jetted onto the recording medium using a drop volume of 3 pL to print an image in which 3 cm×3 cm solid printing portions with a print ratio of 100% were arranged adjacent to one another in CMYK order. Within 10 seconds of the completion of printing, the printed matter was fed into a 50° C. air oven and dried for three minutes, thus obtaining solid printed matter. The above conveyor speed was set to one of three speeds: 40 m/min, 60 m/min and 80 m/min, with printing conducted under each of these conditions to obtain printed matter. For a portion of the ink sets described below, the same printing was also conducted at a conveyor speed of 100 m/min.

(81) The various combinations of recording media an inkjet inks used in producing the above printed matter were as shown below in Table 6.

(3) Evaluations of Printed Matter

(82) The printed matter for evaluating aggregation properties and the solid printed matter produced above were subjected to each of the evaluations described below. The evaluation results obtained are shown below in Table 6.

(83) TABLE-US-00008 TABLE 6 Evaluation results Recording Recording Initial medium medium Aggregation Cov- with with aged Coating properties erage After applied applied film CMYK at 100 at 100 aging treatment treatment Treatment Recording thickness inkjet Aggregation m/min m/min Cov- liquid liquid liquid No. medium (μm) ink set properties printing Coverage printing OD erage Example 1  1a  1d  1 A 3   1 B — A — A A Example 2  2a  2d  2 A 3   1 A — A — A A Example 3  3a  3d  3 A 3   1 A A A B A A Example 4  4a  4d  4 A 3   1 A — A — A A Example 5  5a  5d  5 A 3   1 B — A — A A Example 6  6a  6d  6 A 3   1 A — B — A B Example 7  7a  7d  7 A 3   1 A — B — A B Example 8  8a  8d  8 A 3   1 A — A — A A Example 9  9a  9d  9 A 3   1 A — A — A A Example 10 10a 10d 10 A 3   1 A — A — A A Example 11 11a 11d 11 A 3   1 A — A — A A Example 12 12a 12d 12 A 3   1 A — A — A A Example 13 13a 13d 13 A 3   1 B — A — A A Example 14 14a 14d 14 A 3   1 C — A — A A Example 15 15a 15d 15 A 3   1 A — A — A A Example 16 16a 16d 16 A 3   1 B — A — A A Example 17 17a 17d 17 A 3   1 C — A — A A Example 18 18a 18d 18 A 3   1 B — B — B B Example 19 19a 19d 19 A 3   1 A — A — A A Example 20 20a 20d 20 A 3   1 A — A — A B Example 21 21a 21d 21 A 3   1 A — A — A B Example 22 22a 22d 22 A 3   1 A — A — A A Example 23 23a 23d 23 A 3   1 A — A — A A Example 24 24a 24d 24 A 3   1 A — A — A A Example 25 25a 25d 25 A 3   1 A — A — A A Example 26  3a  3d  3 A 3   2 A A A B A A Example 27  3a  3d  3 A 3   3 A A A B A A Example 28  3a  3d  3 A 3   4 A A B — A B Example 29  3a  3d  3 A 3   5 A B B — A C Example 30  3a  3d  3 A 3   6 B — B — A B Example 31  3a  3d  3 A 3   7 B — A B A A Example 32  3a  3d  3 A 3   8 B — B — A B Example 33  3a  3d  3 A 3   9 C — A B A A Example 34  3a  3d  3 A 3  10 A A A B A A Example 35  3a  3d  3 A 3  11 A A B — B B Example 36  3a  3d  3 A 3  12 A B A B A A Example 37  3a  3d  3 A 3  13 A B A A A A Example 38  3a  3d  3 A 3  14 A B B — B B Example 39  3a  3d  3 A 3  15 B A A A B A Example 40  3a  3d  3 A 3  16 A B A B A A Example 41  3a  3d  3 A 3  17 A A B — A B Example 42  3a  3d  3 A 3  18 A A A B A A Example 43  3a  3d  3 A 3  19 A A A B A A Example 44  3a  3d  3 A 3  20 A A A B A A Example 45  3a  3d  3 A 3  21 A A A B A B Example 46  3a  3d  3 A 3  22 A B B — B B Example 47  3a  3d  3 A 3  23 A B B — B B Example 48  3a  3d  3 A 3  24 A B A B B B Example 49  3a  3d  3 A 3  25 A A A A A A Example 50  3a  3d  3 A 3  26 A A A A A A Example 51  3a  3d  3 A 3  27 A A A A A A Example 52  3a  3d  3 A 3  28 A A A A A A Example 53  3a  3d  3 A 3  29 A A B — A B Example 54  3a  3d  3 A 3  30 A B A A A A Example 55 26a 26d 26 A 3  31 A B B — B C Example 56 27a 27d  3 A  0.4  1 C — A — B A Example 57 28a 28d  3 A 12    1 A — B — B B Example 58 29a 29d  2 B 3   1 A — A — A A Example 59 30a 30d  3 B 3   1 A — A — A A Example 60 31a 31d  4 B 3   1 A — A — A A Example 61 32a 32d  3 C 3   1 B — C — C C Comparative — — — A —  1 D — D — D D Example 1 Comparative 33a 33d 27 A 3   1 B — D — D D Example 2 Comparative 34a 34d 28 A 3   1 D — B — D B Example 3 Comparative 35a 35d 29 A 3   1 D — A — C A Example 4 Comparative 36a 36d 30 A 3   1 B — D — C D Example 5 Comparative 37a 37d 31 A 3   1 A — D — C D Example 6 Comparative 38a 38d 32 A 3   1 D — B — C B Example 7 Comparative  3a  3d  3 A 3  32 C — D — D D Example 8 Comparative  3a  3d  3 A 3  33 C — D — D D Example 9 Comparative  3a  3d  3 A 3  34 C — D — D D Example 10 Comparative 39a 39d 27 B 3   1 B — D — D D Example 11 * In the above table, — indicates that the evaluation was not performed
<Evaluation of Aggregation Properties (Color Mixing)>

(84) Using a microscope, the dot shape of the 4C (CMYK) printed portion of the above printed matter for evaluating the aggregation properties (color mixing) was inspected at a magnification of 200× to evaluate the aggregation properties. The evaluation criteria were as follows, with evaluations of A, B and C deemed to indicate good aggregation properties.

(85) (Evaluation Criteria)

(86) A: at all three printing speeds, the dots in the 4C printed portion remained independent and no color mixing was observed. B: at 40 m/min and 60 m/min, the dots in the 4C printed portion remained independent and no color mixing was observed, but at 80 m/min, color mixing of the dots was observed. C: at 40 m/min, the dots in the 4C printed portion remained independent and no color mixing was observed, but at 60 m/min and 80 m/min, color mixing of the dots was observed. D: at all three printing speeds, color mixing of the dots in the 4C printed portion was observed.
<Evaluation of Aggregation Properties (Color Mixing) when Printing at 100 m/min>

(87) Among the ink sets that were evaluated above, those that used the recording medium 3a as the recording medium with the applied treatment liquid, and exhibited an evaluation result of A for the aggregation properties were used to produce printed matter under altered printing conditions. In other words, those ink sets for which no color mixing of the dots was observed in the 4C printed portion even when the printing speed was 80 m/min were each used to produce printed matter for evaluating the aggregation properties (color mixing) at a conveyor speed of 100 m/min, and the aggregation properties were then evaluated. The evaluation method was the same as that described above for the aggregation properties, and the evaluation criteria were as follows.

(88) (Evaluation Criteria)

(89) A: even at a printing speed of 100 m/min, the dots in the 4C printed portion remained independent and no color mixing was observed. B: at a printing speed of 100 m/min, color mixing of the dots in the 4C printed portion was observed.
<Evaluation of Coverage (Initial)>

(90) Using a microscope, the solid printed matter described above was inspected at a magnification of 200×, and for each color, an evaluation was made as to whether voids were absent and banding was absent. The evaluation criteria were as follows, with evaluations of A, B and C deemed to indicate good coverage. The evaluation result recorded in Table 6 represents the worst evaluation result among the four colors.

(91) (Evaluation Criteria)

(92) A: at all three printing speeds, neither voids nor banding was observed. B: at 40 m/min and 60 m/min, neither voids nor bands were observed, but at 80 m/min, voids or bands were observed. C: at 40 m/min, neither voids nor bands were observed, but at 60 m/min and 80 m/min, voids or bands were observed. D: at all three printing speeds, voids or bands were observed.
<Evaluation of Coverage (Initial) when Printing at 100 m/min>

(93) Among the ink sets that were evaluated above, those that used the recording medium 3a as the recording medium with the applied treatment liquid, and exhibited an evaluation result of A for the coverage (initial) were used to produce printed matter under altered printing conditions. In other words, those ink sets for which neither voids nor bands were observed even when the printing speed was 80 m/min were each used to produce printed matter at a conveyor speed of 100 m/min, and the coverage was then evaluated. The evaluation method was the same as that described above for the coverage evaluation, and the evaluation criteria were as follows.

(94) (Evaluation Criteria)

(95) A: even at a printing speed of 100 m/min, neither voids nor banding was observed. B: at a printing speed of 100 m/min, voids or bands were observed.
<Evaluation of Printed Matter OD (Density)>

(96) The OD value of the aforementioned solid printed matter was measured for each color under Status T conditions using a spectroscopic colorimeter X-RITE 528. The passing grade for the measured OD value was set to 1.55 or higher for cyan, 1.50 or higher for magenta, 1.03 or higher for yellow, and 1.70 or higher for black. The number of colors that satisfies the respective passing grade was determined, and the OD was evaluated against the following evaluation criteria. Evaluations of A, B and C were deemed to indicate a favorable level for practical application.

(97) (Evaluation Criteria)

(98) A: in all of the magenta, yellow, cyan and black regions, the OD value satisfied the passing grade. B: in three regions among the magenta, yellow, cyan and black regions, the OD value satisfied the passing grade. C: in two regions among the magenta, yellow, cyan and black regions, the OD value satisfied the passing grade. D: among the magenta, yellow, cyan and black regions, the OD value satisfied the passing grade for not more than one color.

(4) Evaluation of Ink Sets after Aging

(99) <Production of Ink Sets after Aging>

(100) Ten kg of each of the above treatment liquids 1 to 32 and each of the CMYK inkjet ink sets 1 to 34 was placed in an 18-liter drum, and with the drum unsealed in an open state, the drum was left to stand for one week at room temperature. Subsequently, the solid fraction concentration of each treatment liquid and each inkjet ink was measured, and if the measured value was greater than that prior to the standing period (the initial value), then water was added to adjust the solid fraction concentration to the same as that prior to standing, thus completing preparation of aged treatment liquids 1 to 32 and aged CMYK inkjet ink sets 1 to 34.

(101) <Evaluation of Coverage (after Aging)>

(102) Using the above aged treatment liquids 1 to 32, the same method as that described above was used to produce recording media 1d to 39d with the applied aged treatment liquids. Further, using these recording media 1d to 39d with the applied aged treatment liquids and the aged CMYK inkjet ink sets 1 to 34 described above, the same method as that described above for evaluating the coverage was used to evaluated the coverage after aging. The evaluation criteria were the same as described above. The evaluation results are shown in Table 6.

(103) <Evaluation of Jetting Stability of Inkjet Inks>

(104) Using the method described below, each of the aged CMYK inkjet ink sets 1 to 31 produced in the manner described above was used to evaluate the jetting stability simulating the state following a long run. The evaluation results are shown in Table 7.

(105) First, an inkjet jetting apparatus fitted with four inkjet heads KJ4B-1200 (manufactured by Kyocera Corporation) was prepared, and the K, C, M and Y inkjet inks that constitute the aged CMYK inkjet ink set were used to fill these heads in sequence from the upstream side. Then, under conditions including a drop volume of 3 pl and a drive frequency of 64 kHz, ink was jetted continuously from all of the nozzles for two hours. Subsequently, a nozzle check pattern was printed, and the jetting stability was evaluated by counting the number of missing nozzles. The evaluation criteria were as follows, with evaluations of A, B and C deemed to indicate favorable jetting stability. A: in the nozzle check pattern printed 2 hours after starting printing, there were no missing nozzles. B: in the nozzle check pattern printed 2 hours after starting printing, there were 1 or 2 missing nozzles. C: in the nozzle check pattern printed 2 hours after starting printing, there were 3 or 4 missing nozzles. D: in the nozzle check pattern printed 2 hours after starting printing, there were 5 or more missing nozzles.

(106) TABLE-US-00009 TABLE 7 CMYK inkjet Evaluation results ink set Jetting stability 1 A 2 A 3 A 4 A 5 B 6 A 7 A 8 A 9 A 10 A 11 A 12 A 13 A 14 A 15 A 16 A 17 C 18 A 19 A 20 A 21 A 22 A 23 A 24 A 25 A 26 A 27 A 28 A 29 B 30 A 31 A

(107) Based on the above results, it is evident that by using an ink set of the present invention, favorable density and color gamut can be achieved, and images of high image quality with good suppression of image defects such as color mixing caused by dot coalescence and recording medium exposure and banding caused by insufficient coverage can be obtained on various paper media when inkjet printing is conducted at high speed and at high recording resolution.