JP5659879B2 - Ink set, manufacturing method thereof, and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an ink set, a method for manufacturing the ink set, and an ink jet recording apparatus.

  For water-based pigment inks for inkjet, high image density, scratch resistance (resistance to dirt when rubbing paper with ink attached), storage stability, ink ejection stability from the head, bleeding resistance, etc. are required. It has been.

  Patent Document 1 discloses an ink jet recording ink containing carbon black, a dispersant, polyurethane resin particles, and water. At this time, the carbon black is channel black and / or gas black, the polyurethane resin particles are anionic self-emulsifying ether-based polyurethane resin particles, and the anionic self-emulsifying ether-based polyurethane resin particles have an acid value of 40. 120 or less, a molecular weight of 500 or more and 50000 or less, and an average primary particle diameter of 20 nm or less.

  However, there is a problem that color bleeding occurs between colors other than black.

  The present invention has been made in view of the above-described problems of the prior art, an ink set capable of suppressing the occurrence of color bleeding between black and a color other than black, a method for manufacturing the ink set, and ink jet recording having the ink set. An object is to provide an apparatus.

The invention according to claim 1 is an ink set having a black ink and a color ink other than black, wherein the black ink and the color ink other than black are water, a surfactant, A first pigment, a colored particle containing a second pigment and a resin having a hydrophilic group, and an anionic polyurethane particle, wherein the first pigment is dispersed in the water by the surfactant; The content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the black ink are respectively S (Bk) [mass%] and R (Bk) [mass%]. ] And U (Bk) [mass%], the content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the ink of a color other than black are respectively S (CL) Mass%], R (CL) [mass%] and U (CL) [mass%], the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)] ≦ 100
1 ≦ [R (Bk) + S (Bk)] / [R (CL) + S (CL)] ≦ 10
2 ≦ R (Bk) + S (Bk) ≦ 20
0.2 ≦ U (Bk) / U (CL) ≦ 5
0.5 ≦ U (Bk) ≦ 1.8
It is characterized by satisfying.

  The invention according to claim 2 is the ink set according to claim 1, wherein the weight average molecular weight of the polyurethane particles contained in the black ink is the weight average of the polyurethane particles contained in the ink of a color other than black. It has a molecular weight or more.

The invention according to claim 3 is the ink set according to claim 1 or 2, wherein the polyurethane particles contained in the black ink have a weight average molecular weight of 1.3 × 10 ⁴ or more and 3.0 × 10 ^4. It is characterized by the following.

  According to a fourth aspect of the present invention, in the ink set according to any one of the first to third aspects, the black ink and the color ink other than the black each have an average particle diameter (D50) of 70 nm. It is characterized by being 150 nm or less.

The invention according to claim 5 is a method of manufacturing an ink set having a black ink and a color ink other than black, wherein the black ink and the color ink other than black are water, A step of producing a black ink and an ink of a color other than black, comprising a surfactant, a first pigment, a colored particle comprising a second pigment and a resin having a hydrophilic group, and an anionic polyurethane particle; Preparing a first liquid in which the first pigment is dispersed in the water by the surfactant and preparing a second liquid in which the colored particles are dispersed in the water, respectively. The content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the black ink are respectively S (Bk) [mass%], (Bk) [mass%] and U (Bk) [mass%], the content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the color ink other than the black When the amounts are S (CL) [mass%], R (CL) [mass%] and U (CL) [mass%], respectively, the formula 1 ≦ [R (Bk) / S (Bk)] / [ R (CL) / S (CL)] ≦ 100
1 ≦ [R (Bk) + S (Bk)] / [R (CL) + S (CL)] ≦ 10
2 ≦ R (Bk) + S (Bk) ≦ 20
0.2 ≦ U (Bk) / U (CL) ≦ 5
0.5 ≦ U (Bk) ≦ 1.8
It is characterized by satisfying.

According to a sixth aspect of the present invention, in the method of manufacturing the ink set according to the sixth aspect, the average particle diameter (D50) of the first liquid prepared when the black ink is manufactured is set to D (S −Bk) [nm], where D (S−CL) [nm] is the average particle diameter of the first liquid prepared when the ink of a color other than black is manufactured, the formula 60 ≦ D (S −CL) ≦ D (S−Bk) ≦ 130
It is characterized by satisfying.

  According to a seventh aspect of the present invention, in the ink jet recording apparatus, the ink set according to any one of the first to fourth aspects is provided.

  According to the present invention, it is possible to provide an ink set capable of suppressing the occurrence of color bleeding between black and a color other than black, a method for manufacturing the ink set, and an ink jet recording apparatus having the ink set. .

It is a perspective view which shows an example of the inkjet recording device of this invention. It is the schematic which shows the whole structure of the inkjet recording device of FIG. FIG. 3 is a partially enlarged view of the ink jet recording apparatus of FIG. 2. It is the schematic which shows an example of the ink cartridge used by this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

The ink set of the present invention has a black ink and an ink of a color other than black, and the black ink and the ink of a color other than black are water, a surfactant, a first pigment, and a second ink, respectively. Colored particles containing a pigment and a resin having a hydrophilic group and anionic polyurethane particles are included. At this time, the first pigment is dispersed in water by the surfactant. Further, the content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the black ink are respectively set to S (Bk) [mass%], R (Bk) [mass%] and U (Bk) [mass%], the content of the first pigment, the content of the second pigment, and the content of polyurethane particles in the ink of a color other than black are respectively S (CL) [mass% ], R (CL) [mass%] and U (CL) [mass%], the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)] ≦ 100
1 ≦ [R (Bk) + S (Bk)] / [R (CL) + S (CL)] ≦ 10
2 ≦ R (Bk) + S (Bk) ≦ 20
0.2 ≦ U (Bk) / U (CL) ≦ 5
0.5 ≦ U (Bk) ≦ 1.8
Meet.

The polyurethane particles can be adsorbed on the first pigment dispersed in water by the surfactant and can stabilize the dispersion. At this time, the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)]
Therefore, the number of polyurethane particles not adsorbed on the first pigment in the black ink increases. Here, polyurethane particles that are not adsorbed to the first pigment, that is, free polyurethane particles, have a film-forming action. Therefore, when black ink lands on a recording medium such as paper and moisture evaporates. The viscosity tends to increase. As a result, it is difficult for the black ink to ooze out to the color ink other than black, and color bleeding between colors other than black and black can be suppressed.

  On the other hand, if [R (Bk) / S (Bk)] / [R (CL) / S (CL)] exceeds 100, the image density may decrease. Also, if [R (Bk) + S (Bk)] / [R (CL) + S (CL)] is less than 1, the ejection stability may be reduced, and if it exceeds 10, the image density is reduced. Sometimes. Further, if R (Bk) + S (Bk) is less than 2% by mass, the image density may be lowered, and if it exceeds 20% by mass, the ejection stability may be lowered. Further, when U (Bk) / U (CL) is less than 0.2, the ejection stability or scratch resistance may be lowered, and when it exceeds 5, the ejection stability or the storage stability is lowered. There is. Further, when U (Bk) is less than 0.5% by mass, the storage stability and scratch resistance may decrease, and when it exceeds 1.8, the ejection stability and image density may decrease. .

Further, the formula 1 ≦ [R (Bk) / S (Bk)] − [R (CL) / S (CL)] ≦ 3.5
It is preferable to satisfy. 2. When [R (Bk) / S (Bk)]-[R (CL) / S (CL)] is less than 1, color bleeding between colors other than black and non-black may occur. If it exceeds 5, the image density of black may decrease.

  Although it does not specifically limit as a polyurethane particle, The particle | grains etc. which are contained in a polyurethane emulsion can be used.

  The polyurethane emulsion is an O / W type emulsion, and includes an emulsion obtained by emulsifying polyurethane using an emulsifier and a self-emulsification type emulsion in which a functional group having the function of an emulsifier is introduced by copolymerization or the like. Among these, self-emulsification type emulsions are preferred because they are excellent in dispersion stability in combination with pigments and dispersants. At this time, an ether type emulsion is preferable from the viewpoint of the fixing property of the pigment and the dispersion stability.

  Examples of commercially available polyurethane emulsions include SF460, SF460S, SF420, SF110, SF300, SF361 (Nihon Unicar), Bondick series (DIC), Takelac W, WS series (Mitsui Chemicals), and the like. .

  The weight average molecular weight of the polyurethane particles contained in the black ink is preferably equal to or higher than the weight average molecular weight of the polyurethane particles contained in the color ink other than black. If the weight average molecular weight of the polyurethane particles contained in the black ink is less than the weight average molecular weight of the polyurethane particles contained in the color ink other than black, the scratch resistance may be lowered.

The polyurethane particles contained in the black ink preferably have a weight average molecular weight of 1.3 × 10 ^{4 to} 3.0 × 10 ⁴ . When the weight average molecular weight of the polyurethane particles contained in the black ink is less than 1.3 × 10 ⁴ , the scratch resistance may be lowered, and when it exceeds 3.0 × 10 ⁴ , the ejection stability of the black ink is decreased. May decrease.

  The number average molecular weight and the weight average molecular weight are molecular weights in terms of polystyrene measured by GPC using N-methyl-2-pyrrolidone as a developing solvent.

  In the present invention, the polyurethane emulsion may be used alone or in combination with an acrylic resin emulsion, a styrene-acrylic resin emulsion, an acrylic-silicone resin emulsion, a fluororesin emulsion or the like.

  Commercially available styrene-acrylic resin emulsions include J-450, J-734, J-7600, J-352, J-390, J-7100, J-741, J74J, J-511, J-840, J-775, HRC-1645, HPD-71 (above, manufactured by Johnson Polymer Co., Ltd.) and the like.

  Examples of commercially available acrylic-silicone resin emulsions include UVA383MA (BASF) and AP4710 (Showa Polymer Co., Ltd.).

  Examples of commercially available fluororesin emulsions include FE4300, FE4500, and FE4400 (above, manufactured by Asahi Glass Co., Ltd.).

  The pigment contained in each color ink is not particularly limited, but azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, aniline black, azomethine, Organic pigments such as rhodamine B lake pigment and carbon black; inorganic pigments such as iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, metal powder, etc. Two or more species may be used in combination.

  The first pigment and the second pigment may be the same or different.

Carbon black contained in the black ink is manufactured using a furnace method and a channel method, has a primary particle size of 15 to 40 nm, a BET specific surface area of 50 to 300 m ² / g, and a DBP oil absorption amount. It is preferable that it is 40-150 ml / 100g, a volatile matter is 0.5-10%, and pH is 2-9.

  As a commercial product of carbon black, No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (above, manufactured by Mitsubishi Chemical Corporation), Raven700, 5750, 5250, 5000, 3500, 1255 (above, manufactured by Columbia), Regal400R, 330R, 660R, MoguL, Monarch700, 800, 880, 900, 1000, 1100, 1300 , Monarch 1400 (manufactured by Cabot Corporation), Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, 4 ( As mentioned above, Degussa) and the like can be mentioned.

  The color ink other than black is not particularly limited, and yellow, magenta, cyan, red, green, blue, and the like can be used.

  Commercially available pigments contained in yellow ink include C.I. I. Pigment Yellow 1 (Fast Yellow G), 2, 3, 12 (Disazo Yellow AAA), 13, 14, 16, 17, 20, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55 73, 74, 75, 81, 83 (disazo yellow HR), 86, 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185 and the like.

  Commercially available pigments contained in magenta ink include C.I. I. Pigment Red 1, 2, 3, 5, 7, 9, 12, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 1 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B) (Ca)), 48: 3 (permanent red 2B (Sr)), 48: 4 (permanent red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (brilliant carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 92, 97, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 175, 176, 178, 179, 18 , And the like 184,185,190,192,193,202,209,215,216,217,219,220,223,226,227,228,238,240,254,255,272.

  Commercially available pigments contained in cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 22, 56, 60, 63, 64, Bat Blue 4, Bat Blue 60, and the like.

  Commercial products of pigments contained in red, green and blue inks include C.I. I. Pigment red 177, 194, 224, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 71, C.I. I. Pigment violet 3, 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment green 7, 36, and the like.

  As the surfactant, a nonionic surfactant, an anionic surfactant, or an amphoteric surfactant can be used.

  The nonionic surfactant is not particularly limited, but polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; Polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether; polyoxyethylene-α-naphthyl ether, polyoxyethylene-β-naphthyl ether, polyoxyethylene monostyryl phenyl ether, polyoxy Ethylene distyryl phenyl ether, polyoxyethylene alkyl naphthyl ether, polyoxyethylene monostyryl naphthyl ether And polyoxyethylene distyryl naphthyl ether. In addition, polyoxyethylene polyoxypropylene block copolymers obtained by substituting part of polyoxyethylene of these nonionic surfactants with polyoxypropylene, and compounds having an aromatic ring such as polyoxyethylene alkylphenyl ether are formalin. A condensate condensed with the above can also be used.

  The HLB of the nonionic surfactant is preferably 12 to 19.5, and more preferably 13 to 19. When the HLB of the nonionic surfactant is less than 12, the familiarity of the nonionic surfactant with water may decrease, and the dispersion stability of the first pigment may decrease, and when it exceeds 19.5, The nonionic surfactant may be difficult to adsorb to the first pigment, and the dispersion stability of the first pigment may be reduced.

  The anionic surfactant is not particularly limited, but polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene monostyryl phenyl ether sulfate, polyoxyethylene distyryl phenyl ether sulfate, Polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, polyoxyethylene monostyryl phenyl ether phosphate, polyoxyethylene distyryl phenyl ether phosphate, polyoxyethylene alkyl ether carboxylate, Polyoxyethylene alkyl phenyl ether carboxylate, polyoxyethylene monostyryl phenyl ether carboxylate, polyoxyethylene distyryl phenyl ether carbonate Condensates obtained by condensing phosphates, naphthalene sulfonates with formalin, condensates obtained by condensing melanin sulfonates with formalin, dialkyl sulfosuccinic acid ester salts, alkyl sulfosuccinates, polyoxyethylene alkyl sulfosuccinic acid disalts Alkyl sulfoacetate, α-olefin sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfonate, N-acyl amino acid salt, acylated peptide, soap and the like.

  The amphoteric surfactant is not particularly limited, and examples thereof include lauryl dimethyl betaine, N-alkyl glycine, alkyldiaminoethyl glycine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine and the like.

  The colored particles can be produced by microencapsulation using a resin having a second pigment and a hydrophilic group.

The method for microencapsulating the second pigment is not particularly limited, and examples thereof include a chemical production method, a physical production method, a physicochemical production method, and a mechanical production method. Specific examples are described below.
Interfacial polymerization method (2 monomers or 2 reactive substances are dissolved separately in an organic solvent and an aqueous solvent in which the second pigment is dispersed, and then at the interface between the organic solvent phase and the aqueous solvent phase. How to react)
In-situ polymerization method (a method in which a liquid or gaseous monomer and catalyst, or two reactive substances are supplied from an aqueous solvent phase or an organic solvent phase in which a second pigment is dispersed and reacted)
・ Liquid-cured coating method (drop the dispersion droplet in which the second pigment is dispersed in a solution in which a resin having a hydrophilic group is dissolved in an organic solvent). Method)
・ Coacervation (phase separation) method (dispersion in which the second pigment is dispersed in a solution in which a resin having a hydrophilic group is dissolved in an organic solvent) And to separate into a dilute phase)
-In-liquid drying method (After a dispersion in which the second pigment is dispersed in a solution in which a resin having a hydrophilic group is dissolved in an organic solvent is poured into an aqueous solvent to form a composite emulsion. , How to remove organic solvent)
-Melt dispersion cooling method (method of cooling a dispersion liquid in which a second pigment is dispersed in a melt obtained by melting a resin having a hydrophilic group that solidifies at room temperature, and then cooling it)
・ Air suspension coating method (a method of spraying a liquid containing a resin having a hydrophilic group while floating the second pigment in an air stream using a fluidized bed)
・ Spray drying method (a method in which a dispersion liquid in which a second pigment is dispersed in a solution in which a resin having a hydrophilic group is dissolved in an organic solvent is sprayed and contacted with hot air to evaporate the organic solvent)
-Acid precipitation method (at least part of the anionic group of the resin having an anionic group is neutralized with a basic compound, kneaded with an aqueous solvent in an aqueous solvent, and then neutralized or acidic with an acidic compound) , A method of precipitating a resin and further neutralizing with a basic compound)
・ Phase inversion emulsification method (injecting water into a dispersion in which a second pigment is dispersed in a solution in which a resin having an anionic group is dissolved in an organic solvent, or injecting a dispersion into water) how to)
Examples of the resin having a hydrophilic group include polyamide, polyurethane, polyester, epoxy resin, polycarbonate, urea resin, melamine resin, phenol resin, polysaccharide, gelatin, gum arabic, dextran, casein, protein, natural rubber, carboxypoly Methylene, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, cellulose, ethyl cellulose, methyl cellulose, nitrocellulose, hydroxyethyl cellulose, cellulose acetate, polyethylene, polystyrene, (meth) acrylic acid polymer or copolymer Polymer, copolymer or copolymer of (meth) acrylic acid ester, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene- (meth) acrylic acid copolymer , Styrene - maleic acid copolymer, sodium alginate, fatty acids, paraffin, beeswax, water wax, hardened beef tallow, carnauba wax, albumin and the like. Among them, a resin having an anionic group such as a carboxyl group or a sulfonic acid group is preferable.

  Examples of the resin having a nonionic group as the hydrophilic group include polyvinyl alcohol, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, and a cationic ring-opening polymer of 2-oxazoline. Among them, a completely saponified product of polyvinyl alcohol is preferable because it has low water solubility, easily dissolves in hot water, and hardly dissolves in cold water.

  In addition, it is preferable to select a resin having a hydrophilic group depending on the method of microencapsulation. For example, when the interfacial polymerization method is used, it is preferable to use polyester, polyamide, polyurethane, polyvinyl pyrrolidone, epoxy resin or the like as the resin having a hydrophilic group. When the in-situ polymerization method is used, as the resin having a hydrophilic group, a polymer or copolymer of (meth) acrylic acid ester, (meth) acrylic acid- (meth) acrylic acid ester copolymer, styrene- It is preferable to use a (meth) acrylic acid copolymer, polyvinyl chloride, polyvinylidene chloride, polyamide or the like. When using the liquid curing method, it is preferable to use sodium alginate, polyvinyl alcohol, gelatin, albumin, epoxy resin, etc. as the resin having a hydrophilic group. When using the coacervation method, it is preferable to use gelatin, celluloses, casein, or the like as the resin having a hydrophilic group.

The number average molecular weight of the resin having a hydrophilic group is preferably 2 × 10 ³ or more in consideration of microencapsulation.

  The mass ratio of the resin having a hydrophilic group to the second pigment is preferably 0.10 to 0.90, and more preferably 0.20 to 0.70. If the mass ratio of the resin having a hydrophilic group to the second pigment is less than 0.10, it may be difficult to coat the surface of the second pigment, and if it exceeds 0.90, Color developability may be reduced.

  When a self-dispersing organic pigment or self-dispersing carbon black is used as the second pigment, even if the content of the resin having a hydrophilic group in the colored particles is relatively small, Since the dispersibility is improved, the storage stability of the ink can be ensured.

  The aqueous solvent used for microencapsulation is not particularly limited, but alkyl alcohols such as methanol, ethanol, propanol and butanol; aromatic hydrocarbons such as benzol, toluol and xylol; methyl acetate, ethyl acetate, Esters such as butyl acetate; Chlorinated hydrocarbons such as chloroform and ethylene dichloride; Ketones such as acetone and methyl isobutyl ketone; Ethers such as tetrahydrofuran and dioxane; Cellosolves such as methyl cellosolve and butyl cellosolve .

  The colored particles are preferably purified by microencapsulation and then purified by centrifugation, filtration, or the like.

  The average particle diameter (D50) of the colored particles is preferably 50 to 180 nm.

  The average particle diameter (D50) is obtained by measuring a sample diluted with pure water so that the solid content concentration becomes 0.01% by mass using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.). .

  Each color ink preferably further contains a wetting agent.

  Although it does not specifically limit as a wetting agent, It is preferable to use together the wetting agent A whose boiling point exceeds 250 degreeC, and the wetting agent B whose boiling point is 140-250 degreeC.

  The wetting agent A is not particularly limited as long as it is a polyhydric alcohol having an equilibrium water content of 40% by mass or more in an environment of 23 ° C. and 80% RH, but 1,2,3-butanetriol, Examples include 4-butanetriol (bp190-191 ° C / 24 hPa), glycerin (bp290 ° C), diglycerin (bp270 ° C / 20 hPa), triethylene glycol (bp285 ° C), tetraethylene glycol (bp324-330 ° C), and the like. Among these, glycerin is preferable.

  The wetting agent B is not particularly limited as long as it is a polyhydric alcohol having an equilibrium water content of 40% by mass or more in an environment of 23 ° C. and 80% RH, but diethylene glycol (bp 245 ° C.), 1,3-butanediol ( bp 203-204 ° C.). Of these, 1,3-butanediol is preferable.

  The mass ratio of the wetting agent B to the wetting agent A is usually 10/90 to 90/10.

The equilibrium water content was determined by storing a petri dish weighing 1 g of wetting agent in a desiccator maintained at 23 ± 1 ° C. and 80 ± 3% RH using a saturated aqueous solution of potassium chloride. Water mass) / (Wetting agent mass) × 100
It is obtained by calculating the saturated water content [mass%] represented by

  In addition, wetting agent C may be used in combination with wetting agent A and / or wetting agent B.

  The wetting agent C is not particularly limited, but dipropylene glycol (bp 232 ° C.), 1,5-pentanediol (bp 242 ° C.), 3-methyl-1,3-butanediol (bp 203 ° C.), propylene glycol (bp 187 ° C.) ), 2-methyl-2,4-pentanediol (bp 197 ° C.), ethylene glycol (bp 196-198 ° C.), tripropylene glycol (bp 267 ° C.), hexylene glycol (bp 197 ° C.), polyethylene glycol (viscous liquid to solid) ), Polypropylene glycol (bp 187 ° C), 1,6-hexanediol (bp253-260 ° C), 1,2,6-hexanetriol (bp178 ° C), trimethylolethane (solid, mp 199-201 ° C), trimethylolpropane (Solid, mp61 ° C) etc. Polyhydric alcohol: ethylene glycol monoethyl ether (bp 135 ° C.), ethylene glycol monobutyl ether (bp 171 ° C.), diethylene glycol monomethyl ether (bp 194 ° C.), diethylene glycol monobutyl ether (bp 231 ° C.), ethylene glycol mono 2-ethylhexyl ether (bp 229 ° C.) Polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether (bp 132 ° C.); polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether (bp 237 ° C.) and ethylene glycol monobenzyl ether; N-methyl-2-pyrrolidone (bp 202 ° C.), 1,3-dimethyl-2-imidazolidinone (bp 226 ° C.), ε-caprolactam (bp 270 ° C.), γ-buty Nitrogen-containing heterocyclic compounds such as lactone (bp204-205 ° C); formamide (bp210 ° C), N-methylformamide (bp199-201 ° C), N, N-dimethylformamide (bp153 ° C), N, N-diethylformamide ( amides such as bp 176-177 ° C; monoethanolamine (bp 170 ° C), diethanolamine (bp268 ° C), triethanolamine (bp360 ° C), N, N-dimethylmonoethanolamine (139 ° C), N-methyldiethanolamine (bp243) ), N-methylethanolamine (bp159 ° C), N-phenylethanolamine (bp282-287 ° C), amines such as 3-aminopropyldiethylamine (bp169 ° C); dimethyl sulfoxide (bp139 ° C), sulfolane (bp 85 ° C.), sulfur-containing compounds such as thiodiglycol (bp282 ℃); propylene carbonate, ethylene and the like carbonates.

  Other wetting agents C include solid wetting agents such as saccharides such as monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides and derivatives thereof.

  Specific examples of the saccharide include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose and the like.

  Here, the polysaccharide means a saccharide in a broad sense and includes substances widely present in nature such as α-cyclodextrin and cellulose.

As derivatives of saccharides, the general formula HOCH ₂ (CHOH) _n CH ₂ OH
(In the formula, n is an integer of 2 to 5.)
And reducing sugars such as sugar alcohols; oxidized sugars such as aldonic acid and uronic acid; amino acids and thioic acids. Of these, sugar alcohols such as maltitol and sorbit are preferable.

  Each color ink preferably further contains a penetrant. As a result, the surface tension of the ink is reduced, and after the ink droplets have landed on the recording medium, the ink easily penetrates into the recording medium. Therefore, the occurrence of feathering and color bleeding can be suppressed.

  The penetrating agent is not particularly limited, but is a surfactant such as a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, a fluorosurfactant, a silicone surfactant, or an acetylene glycol surfactant. And two or more of them may be used in combination.

  Nonionic surfactants include polyol, glycol ether, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene Examples thereof include ethylene alkylamine, polyoxyethylene alkylamide, and acetylene glycol.

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.

  Examples of amphoteric surfactants include lauryl dimethyl betaine, N-alkyl glycine, alkyl diaminoethyl glycine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine.

  Fluorosurfactants include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl phosphates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl betaines, perfluoroalkylamine oxide compounds, etc. Can be mentioned.

  Commercially available fluorosurfactants include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-144, S-145 (above, Asahi Glass Co., Ltd.), Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431, FC-4430 (above, manufactured by Sumitomo 3M), Megafuck F-470, F-1405, F-474 (above, manufactured by DIC), Zonyl FS-300, FSN, FSN-100, FSO, FSO-100 (above, made by DuPont), F-top EF-351 352, 801, 802 (above, manufactured by Gemco), FT-250, 251 (above, manufactured by Neos), PF-151N, PF-136A, PF-156A (above, O NOVA Co., Ltd.), and the like. Among these, FSO, FSO-100, FSN, FSN-100, and FS-300 are preferable because of excellent image quality and storage stability.

  Examples of the silicone surfactant include polyether-modified silicone compounds.

  As the polyether-modified silicone compound, a side chain type in which a polyether group is introduced into the side chain of polysiloxane (pendant type), a single-end type in which a polyether group is introduced into one or both ends of the polysiloxane, or a both-end type (ABA type), a side chain of polysiloxane and a side chain both terminal type in which a polyether group is introduced at both ends, a polysiloxane (A) in which a polyether group is introduced, and a polysiloxane in which a polyether group is not introduced (B ABn type, in which a polyether group is introduced at the end of a branched polysiloxane, and the like. Among these, a side chain type (pendant type) is preferable.

  Commercially available silicone surfactants include KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-618, KF-6011, KF-6015. KF-6004 (manufactured by Shin-Etsu Chemical Co., Ltd.), SF-3771, SF-8427, SF-8428, SH-3749, SH-8400, FZ-2101, FZ-2104, FZ-2118, FZ-2203, Examples thereof include FZ-2207, L-7604 (manufactured by Dow Corning Toray), BYK-345, BYK-346, BYK-348 (manufactured by Big Chemie Japan).

  Examples of acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5- Examples include dimethyl-1-hexyn-3-ol.

  Examples of commercially available acetylene glycol surfactants include Surfynol 104, 82, 465, 485, and TG (manufactured by Air Products).

  The content of the penetrant in the ink is preferably 0.05 to 5% by mass, and more preferably 0.1 to 3% by mass.

  In order to improve the penetrability of the ink, a polyol having 8 to 11 carbon atoms such as 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol is used as a penetrant. You may use together.

  Each color ink may further contain an antifoaming agent, a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, an antioxidant, an ultraviolet absorber, and the like as necessary.

  Although it does not specifically limit as an antifoamer, A silicone type antifoamer, a polyether type | system | group antifoamer, a fatty-acid ester type | system | group antifoamer etc. are mentioned, You may use 2 or more types together. Among these, a silicone-based antifoaming agent is preferable because it has an excellent foam breaking effect.

  The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, but is not limited to amines such as diethanolamine and triethanolamine, and alkali metal such as lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the hydroxide include alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate; ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium hydroxide.

  The antiseptic / antifungal agent is not particularly limited, but 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, etc. Is mentioned.

  The rust inhibitor is not particularly limited, and examples thereof include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Although it does not specifically limit as antioxidant, A phenolic antioxidant (a hindered phenolic antioxidant is included), an amine antioxidant, a sulfuric antioxidant, phosphorus antioxidant, etc. are mentioned.

  The ultraviolet absorber is not particularly limited, and examples thereof include oxybenzone, phenyl salicylate, and paraaminobenzoic acid ester.

  Each color ink preferably has an average particle diameter (D50) of 70 to 150 nm. If the average particle diameter (D50) of the ink is less than 70 nm, the scratch resistance may be lowered, and if it exceeds 150 nm, the ejection stability of the ink may be lowered.

  The viscosity of each color ink at 25 ° C. is preferably 5 to 20 mPa · s, and more preferably 6 to 15 mPa · s. If the viscosity at 25 ° C. of the ink is less than 5 mPa · s, the ink may bleed on the recording medium, and if it exceeds 20 mPa · s, the ejection stability of the ink may be reduced.

  Each color ink preferably has a surface tension at 25 ° C. of 20 to 40 mN / m. If the surface tension of the ink at 25 ° C. is less than 20 mN / m, the ink may ooze on the recording medium, and if it exceeds 40 mN / m, the ink hardly penetrates into the recording medium, and drying takes a long time. It may take.

  The ink of each color preferably has a pH of 7-10.

  The steps for producing each color ink include a step of preparing a first liquid in which a first pigment is dispersed in water by a surfactant and a second liquid in which colored particles are dispersed in water. Process.

The average particle diameter (D50) of the first liquid prepared when producing the black ink is D (S-Bk) [nm], and the first liquid prepared when producing the ink of a color other than black. When the average particle diameter of the liquid is D (S-CL) [nm], the formula 60 ≦ D (S-CL) ≦ D (S-Bk) ≦ 130
It is preferable to satisfy. When D (S-CL) is less than 60 nm, the light resistance and storage stability of the ink may be lowered. If D (S-Bk) is less than D (S-CL), color bleeding between colors other than black and black may easily occur. When D (S-Bk) exceeds 130 nm, the saturation of the image may decrease, the viscosity of the ink may increase during storage, or the nozzle may become clogged when ink is ejected.

  The ink set of the present invention can be applied to an ink jet recording apparatus such as an ink jet recording printer, a facsimile apparatus, a copying apparatus, and a printer / fax / copier multifunction machine.

  FIG. 1 shows an example of the ink jet recording apparatus of the present invention. The ink jet recording apparatus 100 includes a paper feed tray 101 for loading paper, a paper discharge tray 102 for stocking paper on which an image is formed, and an ink cartridge loading unit 103. On the upper surface of the ink cartridge loading unit 103, an operation unit 104 on which operation keys, a display, and the like are installed is disposed. The ink cartridge loading unit 103 is provided with an openable and closable cover 103a for attaching and detaching an ink cartridge (not shown).

  In the ink jet recording apparatus 100, as shown in FIGS. 2 and 3, a carriage 107 is slidably held in the main scanning direction A by a guide rod 105 and a stay 106 that are horizontally mounted on left and right side plates (not shown). It is moved and scanned in the main scanning direction A by a main scanning motor (not shown).

  The carriage 107 includes four inkjet heads 108 that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). And are mounted so that the direction in which the ink droplets are ejected is downward.

  The inkjet head 108 is not particularly limited, but a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. A shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like can be used.

  Also, the carriage 107 is equipped with a sub tank 109 for each color for supplying each color ink to the inkjet head 108. The sub tank 109 is supplied with ink according to the ink set of the present invention from an ink cartridge (not shown) loaded in the ink cartridge loading unit 103 via an ink supply tube (not shown).

  On the other hand, as a paper feeding unit for feeding the paper P stacked on the paper stacking unit (pressure plate) 102a of the paper feeding tray 102, the paper feeding is performed by separating and feeding the paper P one by one from the paper stacking unit 102a. A separation pad 111 made of a material having a large friction coefficient is provided so as to face the roller 110 and the paper feeding roller 110. At this time, the separation pad 111 is biased toward the paper feed roller 110 side.

  A transport belt 113 for electrostatically attracting and transporting the paper P as a transport section for transporting the paper P fed from the paper feed section via the guide 112 on the lower side of the inkjet head 108, and the paper P A counter roller 114 for transporting the paper P sandwiched between the transport belt 113 and a transport guide 115 for changing the direction of the paper P transported substantially vertically upward by approximately 90 ° to follow the transport belt 113. Further, a tip pressurizing roller 117 urged toward the conveying belt 113 by the pressing member 116 is installed. A charging roller 118 for charging the surface of the conveyor belt 113 is provided.

  The conveyance belt 113 is an endless belt, is stretched between the conveyance roller 119 and the tension roller 120, and can circulate in the direction B in which the paper P is conveyed. In addition, a guide member 121 is disposed on the back side of the conveyance belt 113 so as to correspond to an image forming area formed by the inkjet head 108.

  The transport belt 113 is not particularly limited, but a surface layer that electrostatically adsorbs a sheet P made of a resin such as a tetrafluoroethylene and ethylene copolymer (ETFE) having a thickness of about 40 μm, and a resistance caused by carbon. Except for being controlled, those having a back layer (medium resistance layer, earth layer) made of the same material as the surface layer can be used.

  As a paper discharge unit for discharging the paper P on which an image is formed by the inkjet head 108, a separation claw 122 for separating the paper P from the transport belt 113, a paper discharge roller 123, and a paper discharge roller 124 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 123.

  A double-sided paper feeding unit 125 is detachably attached to the back surface of the inkjet recording apparatus 100. The double-sided paper feeding unit 125 takes in and reverses the paper P returned by the conveyance belt 113 rotating in the direction opposite to the direction B, and then feeds the paper P between the counter roller 114 and the conveyance belt 113. A manual paper feed unit 126 is installed on the upper surface of the double-sided paper feed unit 125.

  In the ink jet recording apparatus 100, the paper P is separated and fed one by one from the paper feeding unit, and the paper P fed substantially vertically upward is guided by the guide 112 and between the transport belt 113 and the counter roller 114. It is sandwiched and conveyed. Further, the front end is guided by the transport guide 115 and pressed against the transport belt 113 by the front end pressure roller 117, and the transport direction is changed by about 90 °.

  At this time, since the conveyance belt 113 is charged by the charging roller 118, the paper P is electrostatically attracted to the conveyance belt 113 and conveyed. Therefore, by driving the inkjet head 108 in accordance with the image signal while moving the carriage 107, ink droplets are ejected onto the stopped paper P to form an image for one line, and the paper P is transferred by a predetermined amount. After the conveyance, an image for the next line is formed. Upon receiving a signal indicating completion of image formation or a signal indicating that the trailing edge of the paper P has reached the image forming area, the image forming operation is completed, and the paper P is discharged onto the paper discharge tray 103.

  When a near end of the remaining amount of ink in the sub tank 109 is detected, a required amount of ink is supplied to the sub tank 109 from an ink cartridge (not shown).

  In the ink jet recording apparatus 100, when the ink in the ink cartridge is used up, the ink cartridge housing can be disassembled and the ink bag inside can be replaced. Further, the ink cartridge can be stably supplied with ink even when the ink cartridge is vertically placed and has a front loading configuration. Therefore, when the upper side of the ink jet recording apparatus 100 is closed, for example, when it is stored in a rack, or when an object is placed on the upper surface of the ink jet recording apparatus 100. However, the ink cartridge can be easily replaced.

  FIG. 4 shows an example of an ink cartridge used in the present invention. The ink cartridge 200 is used in such a manner that an ink bag 201 filled with ink is accommodated in a plastic casing 202 and is detachably mounted on the inkjet recording apparatus 100.

  The ink bag 201 is composed of a packaging member such as a non-permeable aluminum laminate film and is sealed by fusing the ink injection port 201a after filling and exhausting ink from the ink injection port 201a. Yes. The ink bag 201 is formed with an ink discharge port 201b made of a rubber member. When supplying ink to the sub tank 109, the ink bag 201 is installed at the tip of the ink supply tube. Sting the needle.

  The example in which the ink set of the present invention is applied to a serial type (shuttle type) ink jet recording apparatus that is scanned by a carriage has been described above, but the present invention can be similarly applied to a line type ink jet recording apparatus having a line type head. .

  Examples of the present invention will be described below, but the present invention is not limited to the examples. In addition, a part means a mass part.

[Preparation of first liquid (Bk-1)]
200 parts of carbon black NIPEX 150 (manufactured by Degussa) having a BET specific surface area of 110 m ² / g, an average primary particle size of 29 nm, a pH of 4.0, and a DBP oil absorption of 400 g / 100 g, a dimer of naphthalenesulfonic acid, 3 12.5 parts of sodium naphthalene sulfonate formalin condensate with a content of a monomer and tetramer of 50% by mass Pionein A-45-PN (manufactured by Takemoto Yushi Co., Ltd.) and 788 parts of water are premixed to obtain a mixed slurry. It was. Next, using a disk-type media mill MSC type (manufactured by Mitsui Mining Co., Ltd.), the mixed slurry was circulated for 3 minutes at a filling rate of 70% zirconia beads having a diameter of 15 μm, a peripheral speed of 8 m / s, and a liquid temperature of 10 ° C. Dispersed. Furthermore, after centrifuging coarse particles using a centrifuge Model-7700 (manufactured by Kubota Shoji Co., Ltd.), the solid content is adjusted, and the pigment content is 13% by mass and the average particle size (D50) is 125 nm. A first liquid (Bk-1) was obtained.

[Preparation of first liquid (Bk-2)]
175 parts of carbon black NIPEX160 (manufactured by Degussa) having a BET specific surface area of 150 m ² / g, an average primary particle size of 20 nm, a pH of 4.0, and a DBP oil absorption of 620 g / 100 g, a dimer of naphthalenesulfonic acid, 3 175 parts of sodium naphthalene sulfonate formalin condensate Pionein A-45-PN (manufactured by Takemoto Yushi Co., Ltd.) and 650 parts of water having a content of a monomer and a tetramer of 50% by mass were mixed to obtain a mixed slurry. Next, using a disk type media mill DMR type (manufactured by Ashizawa Finetech), the filling rate of zirconia beads having a diameter of 50 μm is 55%, the peripheral speed is 10 m / s, the liquid temperature is 10 ° C., 3 The mixed slurry was circulated and dispersed for a minute. Furthermore, after centrifuging coarse particles using a centrifuge Model-7700 (manufactured by Kubota Shoji Co., Ltd.), the solid content is adjusted, and the pigment content is 13% by mass and the average particle size (D50) is 100 nm. A first liquid (Bk-2) was obtained.

[Preparation of first liquid (C-1)]
Pigment Blue 15: 3 LIONOL BLUE FG-7351 (Toyo Ink Co., Ltd.) 24 parts, POE (40) β-naphthyl ether 10% by weight aqueous solution 120 parts, and water 16 parts were placed in a 500 ml beaker and Teflon (registered trademark) ) Stir for 3 hours using a coating stir bar. Next, using a batch type table-top sand mill (made by Campe Papio), using a zirconia ball having a diameter of 0.3 mm and dispersing for 8 hours, the solid content was adjusted, and the pigment content was 13% by mass. A first liquid (C-1) having an average particle diameter (D50) of 97 nm was obtained.

[Preparation of first liquid (C-2)]
Except for changing the dispersion time using zirconia balls having a diameter of 0.3 mm to 12 hours, the pigment content was 13% by mass and the average particle diameter ( A first liquid (C-1) having a D50) of 85 nm was obtained.

[Preparation of first liquid (M-1)]
The same as the first liquid (C-1) except that Pigment Red 122 Toner Magenta EO02 (Clariant) was used instead of Pigment Blue 15: 3 LIONOL BLUE FG-7351 (Toyo Ink) Thus, a first liquid (M-1) having a pigment content of 13% by mass and an average particle diameter (D50) of 121 nm was obtained.

[Preparation of first liquid (M-2)]
The same as the first liquid (C-2) except that Pigment Red 122 Toner Magenta EO02 (Clariant) was used instead of Pigment Blue 15: 3 LIONOL BLUE FG-7351 (Toyo Ink) Thus, a first liquid (M-2) having a pigment content of 13% by mass and an average particle diameter (D50) of 103 nm was obtained.

[Preparation of first liquid (Y-1)]
Pigment Yellow 138 LIONOGEN YELLOW 1010 (Toyo Ink Co., Ltd.) 24 parts, POE (40) α-naphthyl ether 10% by weight aqueous solution 120 parts and water 16 parts were placed in a 500 ml beaker and a Teflon (registered trademark) coated stirrer And stirred for 3 hours. Next, using a batch type table-top sand mill (made by Campe Papio), using a zirconia ball having a diameter of 0.3 mm and dispersing for 8 hours, the solid content was adjusted, and the pigment content was 13% by mass. A first liquid (Y-1) having an average particle diameter (D50) of 70 nm was obtained.

[Preparation of first liquid (Y-2)]
Except for changing the dispersion time using a zirconia ball having a diameter of 0.3 mm to 12 hours, the pigment content was 13% by mass, the average particle diameter ( A first liquid (Y-1) having a D50) of 54 nm was obtained.

[Preparation of second liquid (Bk)]
After sufficiently replacing the inside of the 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer AS-6 (manufactured by Toa Gosei Co., Ltd.) and 0.4 g of mercaptoethanol were charged and heated to 65 ° C. Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxyethyl methacrylate, 36.0 g of styrene macromer AS-6 (manufactured by Toagosei Co., Ltd.), mercapto A mixed solution of 3.6 g of ethanol, 2.4 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask in 2.5 hours. Further, a mixed solution of 0.8 g of azobisdimethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask in 0.5 hours. Next, after aging at 65 ° C. for 1 hour, 0.8 g of azobisdimethylvaleronitrile was added and aging was performed for 1 hour. Further, 364 g of methyl ethyl ketone was added to obtain a 50% by mass polymer solution. The polymer had a weight average molecular weight of 1.5 × 10 ⁴ .

  After stirring 28 g of polymer solution, 26 g of carbon black, 13.6 g of 1 mol / L potassium hydroxide solution, 20 g of methyl ethyl ketone and 30 g of water, the mixture was kneaded 20 times using a three-roll mill NR-84A (manufactured by Noritake Company), A paste was obtained. Next, after putting the paste into 200 g of ion-exchanged water and stirring, using an evaporator, methyl ethyl ketone and a part of the water are distilled off, the pigment content is 13% by mass, and the average particle size (D50) is 84 nm. A second liquid (Bk) was obtained.

[Preparation of second liquid (C)]
The pigment content was 13% by mass and the average particle size was the same as in the second liquid (Bk) except that a copper phthalocyanine pigment (CI Pigment Cyan 15: 3) was used instead of carbon black. A second liquid (C) having a (D50) of 93 nm was obtained.

[Preparation of second liquid (M)]
Instead of carbon black, C.I. I. A second liquid (M) having a pigment content of 13 mass% and an average particle diameter (D50) of 127 nm was obtained in the same manner as in the second liquid (Bk) except that CI Pigment Red 122 was used.

[Preparation of second liquid (Y)]
Instead of carbon black, C.I. I. A second liquid (Y) having a pigment content of 13 mass% and an average particle diameter (D50) of 76 nm was obtained in the same manner as in the second liquid (Bk) except that CI Pigment Yellow 74 was used.

[Preparation of polyurethane emulsion 1]
Viscosity and weight average molecular weight were changed based on an anionic self-emulsifying type (ether type) polyurethane emulsion W5025 (manufactured by Mitsui Chemicals). The content of polyurethane particles was 33% by mass, and the average particle size ( A polyurethane emulsion 1 having a D50) of 22 nm and a viscosity at 25 ° C. of 211 mPa · s was obtained. The polyurethane particles had a weight average molecular weight of 2.0 × 10 ⁴ and an acid value of 80 mgKOH / g.

[Preparation of polyurethane emulsion 2]
Viscosity and weight average molecular weight were changed based on an anionic self-emulsifying type (ether type) polyurethane emulsion W5025 (manufactured by Mitsui Chemicals). The content of polyurethane particles was 33% by mass, and the average particle size ( A polyurethane emulsion 2 having a D50) of 24 nm and a viscosity at 25 ° C. of 232 mPa · s was obtained. The polyurethane particles had a weight average molecular weight of 3.0 × 10 ⁴ and an acid value of 80 mgKOH / g.

[Preparation of polyurethane emulsion 3]
Viscosity and weight average molecular weight were changed based on an anionic self-emulsifying type (ether type) polyurethane emulsion W5025 (manufactured by Mitsui Chemicals). The content of polyurethane particles was 33% by mass, and the average particle size ( A polyurethane emulsion 3 having a D50) of 20 nm and a viscosity at 25 ° C. of 199 mPa · s was obtained. The polyurethane particles had a weight average molecular weight of 1.4 × 10 ⁴ and an acid value of 80 mgKOH / g.

[Preparation of polyurethane emulsion 4]
Viscosity and weight average molecular weight were changed based on an anionic self-emulsifying type (ether type) polyurethane emulsion W5025 (manufactured by Mitsui Chemicals). The content of polyurethane particles was 33% by mass, and the average particle size ( A polyurethane emulsion 4 having a D50) of 20 nm and a viscosity at 25 ° C. of 485 mPa · s was obtained. The polyurethane particles had a weight average molecular weight of 1.3 × 10 ⁴ and an acid value of 80 mgKOH / g.

[Preparation of polyurethane emulsion 5]
Viscosity and weight average molecular weight were changed based on an anionic self-emulsifying type (ether type) polyurethane emulsion W5025 (manufactured by Mitsui Chemicals). The content of polyurethane particles was 33% by mass, and the average particle size ( A polyurethane emulsion 5 having a D50) of 22 nm and a viscosity at 25 ° C. of 74 mPa · s was obtained. The polyurethane particles had a weight average molecular weight of 9.3 × 10 ³ and an acid value of 80 mgKOH / g.

[Polyurethane emulsion 6]
As the polyurethane emulsion 6, a cationic self-emulsifying type (polycarbonate type) polyurethane emulsion SF650 having a polyurethane particle content of 25% by mass, an average particle size (D50) of 10 nm, and a viscosity at 25 ° C. of 187 mPa · s (first type) Kogyo Seiyaku Co., Ltd.) was used. The polyurethane particles had a weight average molecular weight of 1.5 × 10 ⁴ and an acid value of 110 mgKOH / g.

[Measurement of average particle diameter (D50)]
Using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50) of the sample diluted with pure water was measured so that the solid content concentration was 0.01% by mass.

[Measurement of viscosity at 25 ° C.]
The viscosity at 25 ° C. was measured using a viscometer RE80L (manufactured by Toki Sangyo Co., Ltd.).

[Measurement of weight average molecular weight]
The weight average molecular weight was measured using HPLC LC-10 (manufactured by Shimadzu Corporation) and column TSKgelα-M (manufactured by Tosoh Corporation). A calibration curve was prepared using N-methyl-2-pyrrolidone as a developing solvent and standard polystyrene (manufactured by Tosoh Corporation) as a standard substance.

[Preparation of black ink]
3-methyl-1,3-butanediol, 2-pyrrolidone and glycerin as wetting agents, 2-ethyl-1,3-hexanediol and zonyl FS-300 (manufactured by Dupont) as antiseptics, antiseptic After stirring Proxel GXL (manufactured by Avicia) and water as a glaze for 1 hour, adding polyurethane emulsion and stirring for 1 hour, the first liquid, the second liquid, and 2- Amino-2-ethyl-1,3-propanediol was added and stirred for 1 hour. Next, pressure filtration was carried out using a membrane filter made of polyvinylidene fluoride having an average pore size of 5.0 μm to obtain a black ink.

  Table 1 shows the formulation of the black ink. In the table, the unit of numerical values is mass%.

表２に、ブラックインクの特性を示す。

Table 2 shows the characteristics of the black ink.

［平均粒径（Ｄ５０）の測定］
マイクロトラックＵＰＡ−１５０（日機装社製）を用いて、固形分濃度が０．０１質量％になるように純水で希釈したサンプルの平均粒径（Ｄ５０）を測定した。

[Measurement of average particle diameter (D50)]
Using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.), the average particle diameter (D50) of the sample diluted with pure water was measured so that the solid content concentration was 0.01% by mass.

[Measurement of viscosity at 25 ° C.]
The viscosity at 25 ° C. was measured using a viscometer RE80L (manufactured by Toki Sangyo Co., Ltd.).

[Evaluation of preservability]
Put the ink in a polyethylene container, seal it, and store it at 70 ° C for 2 weeks, then measure the viscosity and average particle size (D50) at 25 ° C, and reference the initial viscosity and average particle size (D50) at 25 ° C. The preservability was evaluated based on the rate of change. In addition, the case where the rate of change was less than 5% was evaluated as ◯, the case where it was 5% or more and less than 50% as Δ, and the case where it was 50% or more as x.

[Preparation of cyan ink]
1,3-butanediol and glycerin as wetting agents, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and zonyl FS-300 (as penetrants) Dupont), Proxel GXL (Abyssia) as a preservative and antifungal agent, and water are stirred for 1 hour, then a polyurethane emulsion is added and stirred for 1 hour, and the first, second, and pH 2-Amino-2-ethyl-1,3-propanediol as a regulator was added and stirred for 1 hour. Next, pressure filtration was carried out using a membrane filter made of polyvinylidene fluoride having an average pore diameter of 5.0 μm to obtain a cyan ink.

  Table 3 shows the prescription of cyan ink. In the table, the unit of numerical values is mass%.

表４に、シアンインクの特性を示す。

Table 4 shows the characteristics of the cyan ink.

［マゼンタインクの調製］
湿潤剤としての、１，３−ブタンジオール及びグリセリン、浸透剤としての、２−エチル−１，３−ヘキサンジオール、２，２，４−トリメチル−１，３−ペンタンジオール及びゾニールＦＳ−３００（Ｄｕｐｏｎｔ社製）、防腐防黴剤としての、Ｐｒｏｘｅｌ ＧＸＬ（アビシア社製）及び水を１時間撹拌した後、ポリウレタンエマルジョンを添加して１時間撹拌し、第一の液、第二の液及びｐＨ調整剤としての、２−アミノ−２−エチル−１，３−プロパンジオールを添加し、１時間撹拌した。次に、平均孔径５．０μｍのポリビニリデンフルオライド製のメンブレンフィルターを用いて加圧ろ過し、マゼンタインクを得た。

[Preparation of magenta ink]
1,3-butanediol and glycerin as wetting agents, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and zonyl FS-300 (as penetrants) Dupont), Proxel GXL (Abyssia) as a preservative and antifungal agent, and water are stirred for 1 hour, then a polyurethane emulsion is added and stirred for 1 hour, and the first, second, and pH 2-Amino-2-ethyl-1,3-propanediol as a regulator was added and stirred for 1 hour. Next, pressure filtration was performed using a membrane filter made of polyvinylidene fluoride having an average pore size of 5.0 μm to obtain a magenta ink.

  Table 5 shows the magenta ink formulation. In the table, the unit of numerical values is mass%.

表６に、マゼンタインクの特性を示す。

Table 6 shows the characteristics of magenta ink.

［イエローインクの調製］
湿潤剤としての、１，３−ブタンジオール及びグリセリン、浸透剤としての、２−エチル−１，３−ヘキサンジオール、２，２，４−トリメチル−１，３−ペンタンジオール及びゾニールＦＳ−３００（Ｄｕｐｏｎｔ社製）、防腐防黴剤としての、Ｐｒｏｘｅｌ ＧＸＬ（アビシア社製）及び水を１時間撹拌した後、ポリウレタンエマルジョンを添加して１時間撹拌し、第一の液、第二の液及びｐＨ調整剤としての、２−アミノ−２−エチル−１，３−プロパンジオールを添加し、１時間撹拌した。次に、平均孔径５．０μｍのポリビニリデンフルオライド製のメンブレンフィルターを用いて加圧ろ過し、イエローインクを得た。

[Preparation of yellow ink]
1,3-butanediol and glycerin as wetting agents, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and zonyl FS-300 (as penetrants) Dupont), Proxel GXL (Abyssia) as a preservative and antifungal agent, and water are stirred for 1 hour, then a polyurethane emulsion is added and stirred for 1 hour, and the first, second, and pH 2-Amino-2-ethyl-1,3-propanediol as a regulator was added and stirred for 1 hour. Next, pressure filtration was performed using a membrane filter made of polyvinylidene fluoride having an average pore size of 5.0 μm to obtain a yellow ink.

  Table 7 shows the prescription of the yellow ink. In the table, the unit of numerical values is mass%.

表８に、イエローインクの特性を示す。

Table 8 shows the characteristics of the yellow ink.

［印字評価］
実施例１〜１０及び比較例１〜４のインクセット（表９〜１３参照）の印字評価を実施した。具体的には、２４±０．５℃、５０±５％ＲＨの環境下、インクジェットプリンタＩＰＳｉＯ ＧＸ３０００（リコー社製）を用いて、インクの吐出量が等しくなるようにピエゾ素子の駆動電圧を変動させ、同じ量のインクが記録媒体に付着するように設定した。

[Print evaluation]
Printing evaluation of the ink sets of Examples 1 to 10 and Comparative Examples 1 to 4 (see Tables 9 to 13) was performed. Specifically, using an inkjet printer IPSiO GX3000 (manufactured by Ricoh) in an environment of 24 ± 0.5 ° C. and 50 ± 5% RH, the drive voltage of the piezo element is varied so that the ink discharge amount becomes equal. The same amount of ink was set to adhere to the recording medium.

以下に、評価項目及び評価方法を示す。

Evaluation items and evaluation methods are shown below.

[Color bleed]
A high-quality paper Type 6200 (manufactured by Ricoh) having a basis weight of 71.7 g / m ² , a sizing degree of 20.0 seconds, and an air permeability of 22.5 seconds was printed with black 0 in a solid image of cyan, magenta and yellow. A line image of .5 mm was formed, and the color bleed was evaluated by visually observing blurring at the color boundary that was blurred when different color inks were adjacent to each other. In addition, when there is no problem at the color boundary and there is no problem, ◎, when the color boundary is slightly blurred, ○ when there is no problem, and x when there is a problem at the color boundary. Judged.

[Discharge stability]
A chart including a solid image and a line image having the same area and shape as black, cyan, magenta, and yellow has a basis weight of 69.6 g / m ² , a size of 23.2 seconds, and an air permeability of 21.0 seconds. 100 high-quality paper my paper (manufactured by Ricoh) was continuously printed. During printing, when missing ink dots or flying curves were found on the chart, the printer nozzle was cleaned as an operation for returning to normal printing, and the ejection stability was evaluated by the number of cleanings. In addition, the case where the frequency | count of cleaning was 1 times or less was evaluated as (circle), the case where it was 2 times or more and 4 times or less (triangle | delta), and the case where it was 5 times or more as x.

[Abrasion resistance]
Black, cyan, magenta and yellow on a high-quality paper TyPe6200 paper (manufactured by Ricoh) having a basis weight of 71.7 g / m ² , a sizing degree of 20.0 seconds and an air permeability of 22.5 seconds at a resolution of 600 dpi A chart containing a solid image was printed. After drying, the printed part was rubbed 10 times with a cotton cloth, and the transfer of the pigment onto the cotton cloth was visually observed to evaluate the scratch resistance. In the case of black, cyan, magenta and yellow, the case where almost no pigment was transferred to the cotton cloth was observed, and for black, the transfer of the pigment to the cotton cloth was not observed, but cyan, magenta and yellow 1 For color and above, transfer of the pigment to the cotton cloth is observed. For all colors of cyan, magenta and yellow, the transfer of the pigment to the cotton cloth is not observed, but for black, the transfer of the pigment to the cotton cloth is observed. The case where the transfer of the pigment to the cotton cloth was observed for black and the case where the transfer of the pigment to the cotton cloth was observed for one or more colors of cyan, magenta and yellow was determined as x.

[OD value]
Printed on My Paper (Ricoh Co., Ltd.) a chart containing 64 points of black, cyan, magenta, and yellow “■” created using Microsoft Word 2003, and the “■” part using X-Rite 938 Was measured and the OD value was evaluated. At this time, the printing mode was set to “plain paper-standard fast” mode with the driver attached to the printer. For black, ◎ when the OD value is 1.20 or more, ◯ when it is 1.10 or more and less than 1.20, Δ when it is 1.00 or more and less than 1.10, or less than 1.00 The case was determined as x. Cyan is ◎ when the OD value is 1.00 or more, ◯ when it is 0.90 or more and less than 1.00, Δ when it is 0.80 or more and less than 0.90, and less than 0.80. The case was determined as x. Magenta is ◎ when the OD value is 0.90 or more, ◯ when it is 0.80 or more and less than 0.90, Δ when it is 0.70 or more and less than 0.80, or less than 0.70. The case was determined as x. Yellow is ◎ when the OD value is 0.75 or more, ◯ when it is 0.70 or more and less than 0.75, Δ when it is 0.65 or more and less than 0.70, and less than 0.65. The case was determined as x.

  Table 14 shows the results of printing evaluation.

表１４より、実施例１〜１０のインクセットは、式
１≦［Ｒ（Ｂｋ）／Ｓ（Ｂｋ）］／［Ｒ（ＣＬ）／Ｓ（ＣＬ）］
を満たすため、ブラックとブラック以外の色の間のカラーブリードの発生を抑制できることがわかる。一方、比較例１、２のインクセットは、［Ｒ（Ｂｋ）／Ｓ（Ｂｋ）］／［Ｒ（ＣＬ）／Ｓ（ＣＬ）］が１未満であるため、ブラックとブラック以外の色の間のカラーブリードが発生する。また、比較例３のインクセットは、アニオン性のポリウレタン粒子を含まないため、ブラックとブラック以外の色の間のカラーブリードが発生し、保存安定性、吐出安定性及び耐擦過性が低下する。さらに、比較例４のインクセットは、カチオン性のポリウレタン粒子を含むため、ブラックとブラック以外の色の間のカラーブリードが発生し、保存安定性、吐出安定性及び耐擦過性が低下する。

From Table 14, the ink sets of Examples 1 to 10 have the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)].
Thus, it can be seen that the occurrence of color bleeding between black and a color other than black can be suppressed. On the other hand, in the ink sets of Comparative Examples 1 and 2, since [R (Bk) / S (Bk)] / [R (CL) / S (CL)] is less than 1, between black and a color other than black Color bleed occurs. Further, since the ink set of Comparative Example 3 does not contain anionic polyurethane particles, color bleeding between colors other than black and black occurs, and storage stability, ejection stability, and scratch resistance are reduced. Furthermore, since the ink set of Comparative Example 4 contains cationic polyurethane particles, color bleeding between black and a color other than black occurs, and storage stability, ejection stability, and scratch resistance decrease.

JP 2009-173805 A

Claims (7)

An ink set having black ink and ink of a color other than black,
The black ink and the non-black ink are respectively colored particles containing water, a surfactant, a first pigment, a second pigment and a resin having a hydrophilic group, and anionic polyurethane particles. Including
The first pigment is dispersed in the water by the surfactant;
The content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the black ink are respectively S (Bk) [mass%] and R (Bk) [mass%]. ] And U (Bk) [mass%], the content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the ink of a color other than black are respectively S When (CL) [mass%], R (CL) [mass%] and U (CL) [mass%], the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)] ≦ 100
1 ≦ [R (Bk) + S (Bk)] / [R (CL) + S (CL)] ≦ 10
2 ≦ R (Bk) + S (Bk) ≦ 20
0.2 ≦ U (Bk) / U (CL) ≦ 5
0.5 ≦ U (Bk) ≦ 1.8
An ink set characterized by satisfying   2. The ink set according to claim 1, wherein a weight average molecular weight of the polyurethane particles contained in the black ink is equal to or more than a weight average molecular weight of the polyurethane particles contained in the ink of a color other than black. The ink set according to claim 1, wherein the polyurethane particles contained in the black ink have a weight average molecular weight of 1.3 × 10 ⁴ or more and 3.0 × 10 ⁴ or less.   4. The ink set according to claim 1, wherein the black ink and the ink of a color other than black each have an average particle size (D50) of 70 nm or more and 150 nm or less. A method of manufacturing an ink set having black ink and ink of a color other than black,
The black ink and the non-black ink are respectively colored particles containing water, a surfactant, a first pigment, a second pigment and a resin having a hydrophilic group, and anionic polyurethane particles. Including
The steps of manufacturing the black ink and the ink of a color other than black include preparing a first liquid in which the first pigment is dispersed in the water using the surfactant, and coloring Preparing a second liquid in which particles are dispersed in the water,
The content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the black ink are respectively S (Bk) [mass%] and R (Bk) [mass%]. ] And U (Bk) [mass%], the content of the first pigment, the content of the second pigment, and the content of the polyurethane particles in the ink of a color other than black are respectively S When (CL) [mass%], R (CL) [mass%] and U (CL) [mass%], the formula 1 ≦ [R (Bk) / S (Bk)] / [R (CL) / S (CL)] ≦ 100
1 ≦ [R (Bk) + S (Bk)] / [R (CL) + S (CL)] ≦ 10
2 ≦ R (Bk) + S (Bk) ≦ 20
0.2 ≦ U (Bk) / U (CL) ≦ 5
0.5 ≦ U (Bk) ≦ 1.8
An ink set manufacturing method characterized by satisfying: The average particle diameter (D50) of the first liquid prepared when the black ink is manufactured is D (S-Bk) [nm], and is prepared when manufacturing an ink of a color other than the black. When the average particle diameter of the first liquid is D (S-CL) [nm], the formula 60 ≦ D (S-CL) ≦ D (S-Bk) ≦ 130
The method of manufacturing an ink set according to claim 5, wherein:   An ink jet recording apparatus comprising the ink set according to claim 1.

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