JP2012097143A - Method for producing black color-based ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a black color-based ink composition for inkjet-recording, capable of forming an image excellent in ejection stability, abrasion resistance and close adhesion to a recording medium.SOLUTION: This method for producing the black color-based ink composition for inkjet-recording includes obtaining an aqueous dispersion of a carbon black pigment, containing the carbon black pigment as the pigment, obtaining an aqueous dispersion of a coloring pigment, containing at least the one kind of the coloring pigments selected from the group consisting of a magenta pigment, a cyan pigment and an yellow pigment, as the pigment, and mixing the aqueous dispersion of the carbon black pigment, aqueous dispersion of the coloring pigment, a water soluble polymerizable compound and a polymerization initiator.

Description

  The present invention relates to a method for producing a black ink composition.

  Inkjet technology has been applied as an image recording method for recording color images in the fields of office printers, home printers, and the like. A pigment is widely used as a colorant for an ink component used in inkjet, and carbon black is often used for black ink.

In an ink composition using carbon black, it is possible to improve the hue of black ink by using a color pigment in addition to carbon black (see, for example, Patent Document 1). In addition, as a solvent-based UV curable ink, studies have been made to include a phthalocyanine derivative in black ink in order to improve storage stability and curability (see, for example, Patent Document 2).
On the other hand, water-based inks are preferable for reducing the environmental load, but water-based pigment inks have problems such as scratch resistance, and recently, ultraviolet curable water-based pigment inks have been studied.

JP 2000-318293 A JP 2005-264098 A

  In the ink compositions described in Patent Documents 1 and 2, sufficient adhesion to a recording medium may not be obtained when an image is formed. The pigment derivative described in Patent Document 2 contributes to the improvement of the dispersibility of the carbon black pigment, and is essentially different from a so-called pigment intended for coloring.

  An object of the present invention is to provide a method for producing a black ink composition for ink jet recording capable of forming an image having excellent ejection stability and excellent adhesion to a recording medium.

Specific means for solving the above problems are as follows.
<1> Obtaining an aqueous carbon black pigment dispersion containing a carbon black pigment as a pigment, and an aqueous pigment dispersion containing at least one color pigment selected from the group consisting of a magenta pigment, a cyan pigment and a yellow pigment as a pigment And mixing the carbon black pigment aqueous dispersion, the colored pigment aqueous dispersion, the water-soluble polymerizable compound, and the polymerization initiator, and a method for producing a black ink composition for inkjet recording, comprising: .

<2> At least one of the carbon black pigment aqueous dispersion and the colored pigment aqueous dispersion contains a pigment coated with a water-insoluble resin having an acidic group on at least a part of the surface thereof. A method for producing a black ink composition.

<3> The method for producing a black ink composition according to <1> or <2>, wherein the colored pigment aqueous dispersion contains at least one color pigment selected from the group consisting of a magenta pigment and a cyan pigment. .

<4> The method for producing a black ink composition according to any one of <1> to <3>, wherein the polymerization initiator is a compound represented by the following general formula (1).

(In the formula, m and n each independently represent an integer of 0 or more, and m + n represents an integer of 0 to 3)

<5> The method for producing a black ink composition according to any one of <1> to <4>, further comprising mixing colloidal silica.

<6> The volume average secondary particle diameter of the pigment contained in at least one selected from the group consisting of the carbon black pigment aqueous dispersion and the colored pigment aqueous dispersion is 40 nm to 150 nm, <1> to < 5. A method for producing a black ink composition according to any one of 5>.

<7> The method for producing a black ink composition according to any one of <1> to <6>, further comprising mixing an acetylene glycol surfactant.

<8> A black ink composition produced by the production method according to any one of <1> to <7>.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in discharge stability, the manufacturing method of the black-type ink composition for inkjet recording which can form the image excellent in the adhesiveness to a recording medium can be provided.

  In the present invention, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.

<Method for producing black ink composition>
The method for producing a black ink composition for ink jet recording of the present invention (hereinafter also simply referred to as “ink composition”) includes a carbon black dispersion step of obtaining an aqueous dispersion of a carbon black pigment containing a carbon black pigment as a pigment, A color pigment dispersion step for obtaining a color pigment aqueous dispersion containing as a pigment at least one color pigment selected from the group consisting of a magenta pigment, a cyan pigment and a yellow pigment, the carbon black pigment aqueous dispersion, and the color pigment aqueous dispersion A mixing step of mixing a product, a water-soluble polymerizable compound, and a polymerization initiator, and including other steps as necessary.

  Independently of the step of obtaining the aqueous dispersion of the carbon black pigment, by including the step of obtaining the aqueous dispersion containing at least one color pigment selected from the group consisting of a magenta pigment, a cyan pigment and a yellow pigment, A black ink composition having excellent stability can be produced. Further, by irradiating the black ink composition applied on the recording medium with an active energy ray and curing it, an image having excellent adhesion to the recording medium can be formed. This can be attributed to, for example, an improvement in curing sensitivity compared to the case where only a carbon black pigment is used as the pigment.

[Carbon black dispersion process]
The carbon black dispersion step is not particularly limited as long as the carbon black pigment can be dispersed in an aqueous medium, and a commonly used dispersion method can be appropriately selected and applied.
For example, an aqueous carbon black pigment dispersion can be obtained by mixing at least one dispersant and at least one carbon black pigment in an aqueous medium, and dispersing the resulting mixture. The details of the carbon black pigment will be described later.

  The mixing method and the dispersion treatment method are not particularly limited, and a commonly used mixing and stirring device, and a dispersing device such as an ultrasonic dispersing machine, a high-pressure homogenizer, a ball mill, a roll mill, and a high-speed stirring type dispersing machine may be used as necessary. it can.

The dispersant may be either a polymer dispersant or a low molecular surfactant type dispersant. The polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.
As the low molecular surfactant type dispersant, a commonly used low molecular surfactant can be used without particular limitation.

  Among the polymer dispersants, examples of the water-soluble dispersant include hydrophilic polymer compounds. For example, natural hydrophilic polymer compounds include plant polymers such as gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, pectin, quince seed starch, seaweeds such as alginic acid, carrageenan and agar. Examples include molecules, animal polymers such as gelatin, casein, albumin and collagen, and microorganism polymers such as xanthene gum and dextran.

  In addition, in hydrophilic polymer compounds modified from natural products, fiber polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, starch such as sodium starch glycolate and sodium starch phosphate And seaweed polymers such as sodium alginate, propylene glycol alginate, and the like.

  Further, synthetic hydrophilic polymer compounds include vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl methyl ether, non-crosslinked polyacrylamide, polyacrylic acid or alkali metal salts thereof, water-soluble styrene acrylic resins, and the like. Acrylic resin, water-soluble styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, polyvinyl pyrrolidone, polyvinyl alcohol, alkali metal salts of β-naphthalene sulfonic acid formalin condensate, quaternary ammonium and amino And a polymer compound having a salt of a cationic functional group such as a group in the side chain, a natural polymer compound such as shellac, and the like.

  Among these, water-soluble dispersants introduced with carboxyl groups such as homopolymers such as acrylic acid, methacrylic acid, and styrene acrylic acid, and copolymers with monomers having other hydrophilic groups are highly hydrophilic. Preferred as a molecular compound.

As the water-insoluble dispersant among the polymer dispersants, a water-insoluble resin having a hydrophobic constituent unit and a hydrophilic constituent unit can be used. The hydrophilic structural unit is preferably a structural unit having an acidic group, and more preferably a structural unit having a carboxyl group.
Examples of the water-insoluble resin include styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid- (meth) acrylic acid ester copolymer, (meth) acrylic acid ester- (meth) acrylic acid copolymer. Examples thereof include a polymer, a polyethylene glycol (meth) acrylate- (meth) acrylic acid copolymer, a vinyl acetate-maleic acid copolymer, and a styrene-maleic acid copolymer.
More specifically, for example, the water-insoluble resins described in JP-A-2005-41994, JP-A-2006-238991, JP-A-2009-084494, JP-A-2009-191134, and the like are preferably used in the present invention. Can be used.

The carbon black dispersion step in the present invention uses a water-insoluble resin having an acidic group as a dispersant, and a carbon black pigment, a neutralizing agent, water, and a water-soluble organic solvent capable of dissolving or dispersing the water-insoluble resin. Preferably, the method includes a step of obtaining a mixture, a step of dispersing the mixture, and a step of removing at least a part of the water-soluble organic solvent after the dispersion step. By this dispersion treatment method, at least a part of the pigment surface is coated with a water-insoluble resin having an acidic group, and an aqueous carbon black pigment dispersion having excellent dispersion stability can be obtained.
Such a dispersion method is generally called a phase inversion emulsification method. For details of the phase inversion emulsification method, for example, descriptions in JP-A-10-140065, JP-A-11-209672, JP-A-11-172180 and the like can be referred to.

  The water-insoluble resin used for phase inversion emulsification preferably contains a water-insoluble resin having a carboxyl group, from the viewpoint of self-dispersibility and the aggregation rate when the treatment liquid described below comes into contact, and has a carboxyl group, A water-insoluble resin having an acid value of 100 mgKOH / g or less is preferable, and a water-insoluble resin having an acid value of 25 to 100 mgKOH / g is more preferable. In particular, when the ink composition of the present invention is used in combination with a treatment liquid for aggregating components in the ink composition (details will be described later), a polymer dispersion having a carboxyl group and an acid value of 25 to 100 mgKOH / g The agent is effective.

  The weight average molecular weight of the water-insoluble resin is preferably 3,000 to 100,000, more preferably 5,000 to 50,000, still more preferably 5,000 to 40,000, particularly preferably. 10,000 to 40,000.

  The mixing method and the dispersion method in the phase inversion emulsification method are not particularly limited. Dispersion of a generally used mixing and stirring device, ultrasonic dispersing machine, high-pressure homogenizer, ball mill, roll mill, high-speed stirring type dispersing machine, etc. An apparatus can be used.

Moreover, there is no restriction | limiting in particular in a solvent removal process, The method etc. which distill off an organic solvent by conventional methods, such as reduced pressure distillation, can be applied. At this time, in addition to at least a part of the water-soluble organic solvent, a part of the water may be removed.
By removing the water-soluble organic solvent and carrying out phase inversion to an aqueous system, a dispersion of resin-coated carbon black particles in which at least a part of the surface of the carbon black particles is coated with a water-insoluble resin can be obtained. It is preferable that the organic solvent in the obtained dispersion is substantially removed. The amount of the organic solvent here is preferably 0.2% by mass or less, and more preferably 0.1% by mass or less.

  The water-soluble organic solvent used in the phase inversion emulsification method is not particularly limited as long as the water-insoluble resin can be dissolved or dispersed, and can be appropriately selected according to the water-insoluble resin. Specific examples include alcohol solvents, ketone solvents, and ether solvents. Examples of the alcohol solvent include isopropyl alcohol, n-butanol, t-butanol, ethanol and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone. Examples of the ether solvent include dibutyl ether and dioxane. Among these solvents, ketone solvents such as methyl ethyl ketone and alcohol solvents such as isopropyl alcohol are preferable, and ketone solvents such as methyl ethyl ketone are more preferable.

The neutralizing agent is used for neutralizing part or all of the acidic groups and forming a water-insoluble resin in a stable emulsified or dispersed state in water.
Examples of the neutralizing agent include alcohol amines (eg, diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol), alkali metal hydroxides (eg, lithium hydroxide, hydroxide) Sodium, potassium hydroxide, etc.), ammonium hydroxide (eg, ammonium hydroxide, quaternary ammonium hydroxide), phosphonium hydroxide, alkali metal carbonate, etc. Preferably used.

In the carbon black pigment dispersion step of the present invention, the pigment is dispersed using a water-soluble or water-insoluble dispersant as a method of obtaining “a pigment dispersion in which at least a part of the pigment surface is coated with a water-insoluble resin”. After that, it is also preferable that the pigment dispersion is prepared by water-insolubilizing the water-soluble dispersant by crosslinking the dispersant with a crosslinking agent.
Examples of the dispersant include polyvinyls, polyurethanes, polyesters, etc. Among them, polyvinyls are preferable.
The dispersant needs to have a functional group that can be crosslinked by a crosslinking agent in the molecule. The crosslinkable functional group is not particularly limited, and examples thereof include a carboxyl group or a salt thereof, an isocyanate group, an epoxy group, and the like. From the viewpoint of improving dispersibility, the functional group may have a carboxyl group or a salt thereof. preferable.

The dispersant is preferably a copolymer obtained using a carboxyl group-containing monomer as a copolymerization component. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, β-carboxyethyl acrylate, fumaric acid, itaconic acid, maleic acid, crotonic acid and the like. Among these, from the viewpoint of crosslinkability and dispersion stability, (meth) Acrylic acid and β-carboxyethyl acrylate are preferred. (Meth) acrylic acid means at least one of acrylic acid and methacrylic acid.
The copolymer component preferably contains at least one hydrophobic monomer. Examples of hydrophobic monomers include alkyl (meth) acrylates having 1 to 20 carbon atoms, (meth) acrylates having aromatic ring groups such as benzyl (meth) acrylate and phenoxyethyl (meth) acrylate, and styrene and derivatives thereof. Can be mentioned.

The dispersant is a copolymer obtained by using, as a copolymerization component, a carboxyl group-containing monomer and at least one of an alkyl (meth) acrylate having 1 to 20 carbon atoms and a (meth) acrylate having an aromatic ring group. Preferably there is.
The method for synthesizing the copolymer as a dispersant is not particularly limited, but random polymerization of vinyl monomers is preferable from the viewpoint of dispersion stability.

The acid value of the dispersant before crosslinking is preferably 60 to 250 mgKOH / g, more preferably 65 to 150 mgKOH / g, from the viewpoint of dispersibility of the pigment.
The acid value of the dispersant after crosslinking is preferably 25 to 100 mgKOH / g from the viewpoints of stability and ink aggregation.
Further, the weight average molecular weight of the dispersant before crosslinking is not particularly limited, but is preferably 3,000 to 100,000, more preferably 5,000 to 50,000, from the viewpoint of dispersibility of the pigment. More preferably, it is 10,000 to 40,000.

The cross-linking agent is not particularly limited as long as it is a compound having two or more sites that react with the dispersant, but preferably has two or more epoxy groups from the viewpoint of excellent reactivity with a carboxyl group. (A bifunctional or higher functional epoxy compound).
Specific examples include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, and polypropylene glycol diglycidyl. Examples include ether and trimethylolpropane triglycidyl ether, and polyethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether are preferable.

  The molar ratio of the cross-linked site of the cross-linking agent to the cross-linked site of the dispersant is preferably from 1: 1.1 to 1:10 from the viewpoint of the cross-linking reaction rate and the dispersion stability after cross-linking, and from 1: 1.1 to 1: 5 is more preferable, and 1: 1.1 to 1: 3 is most preferable.

  Specifically, for example, a pigment dispersion in which at least a part of the pigment surface is coated with a water-insoluble resin can be produced by the method described in JP-A-2009-190379.

  In the present invention, the mixing mass ratio (p: s) between the carbon black pigment (p) and the dispersant (s) is not particularly limited, and can be appropriately selected depending on the dispersion method and the like. For example, a range of 1: 0.06 to 1: 3 is preferable, a range of 1: 0.125 to 1: 1 is more preferable, and a range of 1: 0.125 to 1: 0.7 is more preferable.

In the present invention, the average particle size of the carbon black pigment in the dispersed state is preferably 10 to 200 nm, more preferably 10 to 150 nm, and further preferably 40 to 150 nm. When the average particle size is 200 nm or less, the color reproducibility is good, the droplet ejection characteristics when droplets are ejected by the ink jet method are good, and when it is 10 nm or more, the light resistance is good. Further, the particle size distribution of the carbon black pigment aqueous dispersion is not particularly limited, and may be either a wide particle size distribution or a monodisperse particle size distribution. Further, two or more carbon black pigment aqueous dispersions having a monodispersed particle size distribution may be mixed and used.
Here, the average particle diameter of the carbon black pigment in the dispersed state indicates the average particle diameter in the inked state, but the same applies to the so-called concentrated ink dispersion in the stage before the inking.

  In addition, the average particle size and particle size distribution of the carbon black pigment in the dispersed state are determined by a dynamic light scattering method using a nanotrack particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.). It is calculated | required by measuring.

(Carbon black pigment)
There is no restriction | limiting in particular as said carbon black pigment. From the viewpoint of image adhesion, abrasion resistance, image density, and the like, a carbon black pigment whose pH is in an acidic to neutral region is preferable. Furthermore, the average primary particle diameter of the carbon black pigment is preferably 10 to 50 nm, and more preferably 10 to 30 nm.
The average primary particle size is a particle size (equivalent to a circle) of 1000 primary particles arbitrarily selected from an image taken using a transmission electron microscope TEM2010 (pressurized voltage 200 kV) manufactured by JEOL Ltd. Diameter) is measured and calculated as the arithmetic average.

The pH of the carbon black pigment is preferably in the acidic to neutral range, since easy dispersibility can be obtained, more preferably pH 2.0 to pH 8.5, and pH 2.5 to pH 8.0. It is particularly preferred.
The pH of the carbon black pigment is measured as the pH (25 ° C.) of the aqueous dispersion of the carbon black pigment.

The DBP absorption amount of the carbon black pigment is not particularly limited, but is preferably 30 ml / 100 g or more and 200 ml / 100 g or less, and more preferably 50 ml / 100 g or more and 150 ml / 100 g or less from the viewpoint of color tone and printing density. .
The DBP absorption is measured by the JIS K6221 A method.

Also, the carbon black BET specific surface area of the pigment is not particularly limited, from the viewpoint of printing density and storage stability, is preferably not more than ^{30 m} 2 / g or more ^{450m 2 / g, 200m 2 /} g or more 400 meters ² / g The following is more preferable.

Examples of the carbon black pigment include those produced by known methods such as a contact method, a furnace method, and a thermal method.
Specific examples include Raven7000, Raven5750, Raven5250, Raven5000ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1200, Raven1190 ULTRAII, Raven1170, Raven1170, Raven1170 Regal 330R, Regal 660R, Mogul L, Black Pearls L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400 (above, manufactured by Cabot), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black S150, Color Black S160, Color Black S160, Color Black S150, Color Black S150, Color Black S150, Color Black S150, Color Black S150, Color Black S150, Color Black S150, Color Black S150 , Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, NIPEX180-IQ, NIPEX170-IQ (manufactured by Degussa), No. 25, no. 33, no. 40, no. 45, no. 47, no. 52, no. 900, no. 2200B, no. 2300, no. 990, no. 980, no. 970, no. 960, no. 950, no. 850, MCF-88, MA600, MA7, MA8, MA100 (above, manufactured by Mitsubishi Chemical Corporation). However, it is not limited to these.

The above carbon black pigments may be used singly or in combination of two or more.
The content ratio of the carbon black pigment in the ink composition of the present invention is not particularly limited, but is preferably 0.5 to 4% by mass from the viewpoint of adhesion, abrasion resistance, and print density, and is preferably 0.8 to It is more preferable that it is 2 mass%.

[Coloring pigment dispersion process]
The color pigment dispersion step is not particularly limited as long as at least one color pigment selected from a magenta pigment, a cyan pigment, and a yellow pigment can be dispersed in an aqueous medium, and a commonly used dispersion method is appropriately selected and applied. can do.
For example, an aqueous colored pigment dispersion can be obtained by mixing at least one dispersing agent and at least one coloring pigment in an aqueous medium and dispersing the resulting mixture. The dispersing agent, the mixing method and the dispersing method are as described above. The color pigment will be described later.

In the present invention, independently of the dispersion treatment of the carbon black pigment, the colored pigment is dispersed to prepare an aqueous colored pigment dispersion, and an ink composition is produced using the dispersion. Thereby, it is possible to constitute a black ink composition that is superior in dispersion stability and ejection stability.
This can be considered to be because, for example, a better dispersion state according to the type of pigment can be obtained. It is also possible to select more appropriate dispersion conditions according to the type of pigment.

  When the black ink composition according to the present invention includes two or more color pigments, the color pigment dispersion step may be a step of mixing and co-dispersing two or more color pigments. It may be a step of monodispersed processing every time. In the present invention, from the viewpoint of ejection stability, it is preferable to prepare an aqueous colored pigment dispersion for each colored pigment.

In the color pigment dispersion step in the present invention, the water-insoluble resin having an acidic group described above is used as a dispersant, and a step of obtaining a mixture containing the color pigment, a neutralizing agent, water, and a water-soluble organic solvent, It is preferable to include a step of dispersing the mixture and a step of removing at least a part of the water-soluble organic solvent after the dispersion treatment step. By carrying out such a dispersion step, a colored pigment aqueous dispersion having excellent dispersion stability can be obtained.
Similar to the carbon black dispersion step described above, the pigment is dispersed using a water-soluble or water-insoluble dispersant, and then the dispersant is cross-linked using a cross-linking agent to insolubilize the dispersant to prepare a dispersion. The method is also a preferred embodiment.
The details of the color pigment dispersion step are the same as those of the carbon black dispersion step described above, and the preferred embodiments are also the same.

  Moreover, as an average particle diameter of the colored pigment in a dispersed state, 10-200 nm is preferable, 10-150 nm is more preferable, and 40-150 nm is further more preferable. When the average particle size is 200 nm or less, the color reproducibility is good, the droplet ejection characteristics when droplets are ejected by the ink jet method are good, and when it is 10 nm or more, the light resistance is good. The particle size distribution of the colored pigment aqueous dispersion is not particularly limited, and may be either a wide particle size distribution or a monodisperse particle size distribution. Two or more color pigment aqueous dispersions having a monodispersed particle size distribution may be mixed and used.

(Color pigment)
The colored pigment in the present invention is at least one selected from a magenta pigment, a cyan pigment, and a yellow pigment. The magenta pigment, cyan pigment, and yellow pigment can be appropriately selected from known organic pigments according to the purpose. Specific examples of the organic pigment used in the present invention are shown below.

Examples of magenta pigments include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 222, C.I. I. Pigment violet 19 and the like.
Among these, from the viewpoints of adhesion and abrasion resistance, C.I. I. Pigment red 122, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. It is preferably at least one selected from pigment violet 19.

Examples of cyan pigments include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment Green 7, and siloxane-crosslinked aluminum phthalocyanine described in US Pat. No. 4,311,775.
Among these, from the viewpoints of adhesion and abrasion resistance, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. C.I. preferably at least one selected from CI Pigment Blue 16. I. Pigment blue 15: 3, C.I. I. More preferably, it is at least one selected from CI Pigment Blue 15: 4.

Examples of the yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.
Among these, from the viewpoints of adhesion and abrasion resistance, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 155, C.I. I. It is preferably at least one selected from Pigment Yellow 185.

  The colored pigment in the present invention more preferably contains at least one magenta pigment and at least one cyan pigment from the viewpoint of adhesion.

  In the present invention, the content ratio of the color pigment to the total amount of the carbon black pigment and the color pigment (color pigment / (carbon black pigment + color pigment)) is not particularly limited, but from the viewpoints of adhesion, abrasion resistance, and ejection properties. From 5% by mass to 60% by mass is preferable, and from 10% by mass to 50% by mass is more preferable.

  In addition, the content ratio of the magenta pigment to the cyan pigment in the colored pigment (magenta pigment / cyan pigment) is not particularly limited, but is 100% by mass or more and 180% by mass or less from the viewpoint of adhesion, abrasion resistance, and color tone. Preferably, it is 120 mass% or more and 150 mass% or less.

[Mixing process]
In the mixing step, at least one carbon black pigment aqueous dispersion, at least one color pigment aqueous dispersion, at least one water-soluble polymerizable compound, and at least one polymerization initiator, However, if necessary, at least one water-soluble organic solvent and at least one surfactant may be further mixed.
There is no restriction | limiting in particular in the mixing method in a mixing process. A commonly used liquid mixing method can be appropriately selected. For example, a general stirring device can be used.

[Filtering process]
In this invention, in addition to the said mixing process, you may provide the filtration process which filters the mixture obtained at the said mixing process as needed. The method for the filtration treatment is not particularly limited, and any of atmospheric filtration, pressure filtration, suction filtration and the like may be used. The filter medium used for filtration is not particularly limited, and can be appropriately selected according to the purpose. Examples thereof include filter paper and membrane filter.

(Polymerizable compound)
In the mixing step, a water-soluble polymerizable compound is used for mixing. Here, water-soluble means that it can be dissolved in water at a certain concentration or more. Specifically, the solubility in water at 25 ° C. is preferably 5% by mass or more, and more preferably 10% by mass or more. The water-soluble polymerizable compound is preferably one that can be dissolved (desirably uniformly) in the aqueous ink composition. Further, the solubility may be increased by adding a water-soluble organic solvent to be described later, and it may be dissolved (desirably uniformly) in the ink composition.

  The water-soluble polymerizable compound in the present invention preferably contains at least one selected from the group consisting of a compound having a (meth) acrylic ester structure in the molecule and a compound having a (meth) acrylamide structure in the molecule. More preferably, at least one compound having a (meth) acrylamide structure in the molecule is contained. Here, the (meth) acrylic ester structure means at least one of a methacrylic ester structure and an acrylic ester structure, and the (meth) acrylamide structure means at least one of a methacrylamide structure and an acrylamide structure.

-Compound having (meth) acrylic ester structure in molecule-
The polymerizable compound having a (meth) acrylic ester structure in the molecule is not limited as long as it is a polymerizable compound having a (meth) acrylic ester structure in the molecule.
The polymerizable compound having a (meth) acrylic ester structure in the molecule is preferably a compound represented by the following general formula (M-1).

In General Formula (M-1), Q ¹ represents an i-valent linking group, and R ¹ represents a hydrogen atom or a methyl group. I represents an integer of 1 or more.

Compound represented by the general formula (M-1) are those unsaturated monomer bonded to the linking group Q ¹ by an ester bond. R ¹ represents a hydrogen atom or a methyl group, preferably a hydrogen atom. Although there is no limit to the valence i of the linking group Q ^1, preferably 2 or more, more preferably 2 to 6 or less, still more preferably 2 to 4.

The linking group Q ¹ is not particularly limited as long as it is a group that can be linked to the (meth) acrylic ester structure, but the linking group is such that the compound represented by the general formula (M-1) satisfies the above-described water solubility. Is preferably selected from. Specific examples include residues from which one or more hydrogen atoms or hydroxyl groups have been removed from the following compound group X.

-Compound group X-
Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 -Butanediol, 2,3-butanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4 -Pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, glycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,5 -Pentanetriol, thioglycol, Methylolpropane, ditrimethylolpropane, trimethylolethane, ditrimethylolethane, neopentyl glycol, pentaerythritol, dipentaerythritol, and their condensates, low molecular weight polyvinyl alcohol, or polyols such as sugars, ethylenediamine, diethylenetriamine, triethylene Polyamines such as tetramine, polyethyleneimine, and polypropylenediamine.

Still linking group Q ^1, methylene, ethylene, propylene, 4 or less of the substituted or unsubstituted alkylene chain of carbon atoms such as butylene group, more pyridine ring, an imidazole ring, a pyrazine ring, piperidine ring, piperazine ring, morpholine ring Examples thereof include a functional group having a saturated or unsaturated heterocyclic ring.

Among these, the linking group Q ¹ is preferably a residue of a polyol containing an oxyalkylene group (preferably an oxyethylene group), and contains three or more oxyalkylene groups (preferably an oxyethylene group). A residue of a polyol is particularly preferable.

  Specific examples of the water-soluble polymerizable compound (M-1) having a (meth) acrylic ester structure in the molecule include the following nonionic compounds, but the present application is not limited thereto.

  Further, as the nonionic polymerizable compound, a (meth) acrylic acid ester having two or more acryloyl groups in one molecule derived from a polyol compound can also be used. Examples of the polyol compound include polyol compounds having two or more hydroxyl groups such as glycol condensates, oligoethers, oligoesters, monosaccharides, and disaccharides.

  Also suitable are (meth) acrylic acid esters with triethanolamine, diethanolamine, trishydroxyaminomethane, trishydroxyaminoethane, and the like.

  Furthermore, specific examples of the water-soluble polymerizable compound (M-1) having a (meth) acrylic ester structure in the molecule include the following cationic compounds. It is not limited.

In the above structure, R represents a residue of a polyol compound. X represents H or CH ₃ , and A ⁻ represents Cl ⁻ , HSO ₄ ^— or CH ₃ COO ^— . Examples of the polyol compound include glycerin, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2,6-hexanetriol, trimethylolpropane, trimethylolmethane, trimethylolethane, and penta. Examples include erythritol, bisphenol A, alicyclic bisphenol A, and condensates thereof. Furthermore, the following structures (cationic compounds 1-11) can also be mentioned as a polymeric compound which has a cationic group.

-Compounds with (meth) acrylamide structure in the molecule-
The compound having a (meth) acrylamide structure in the molecule is not limited as long as it is a polymerizable compound having a (meth) acrylamide structure in the molecule.
The compound having a (meth) acrylamide structure in the molecule is preferably a compound represented by the following general formula (M-2). It is preferable to have the structure of the formula (M-2) because the compatibility between the compound represented by the general formula (1) described later and the polymerizable compound can be improved and the curing sensitivity can be increased.

In General Formula (M-2), Q ² represents a j-valent linking group, and R ² represents a hydrogen atom or a methyl group. J represents an integer of 1 or more.

The compound represented by formula (M-2) are those unsaturated monomers, bonded to the linking group Q ² by an amide bond. R ² represents a hydrogen atom or a methyl group, preferably a hydrogen atom. While the linking group Q is not limited to ^two valence j, preferably 2 or more, more preferably 2 to 6 or less, still more preferably 2 to 4.

The connecting group Q ² is not particularly limited as long as it is capable of linking groups and (meth) acrylamide structure. Details of the linking group Q ² is the same as the linking group Q ^1, preferred embodiment is also the same.

  Specific examples of the water-soluble polymerizable compound having a (meth) acrylamide structure in the molecule include the following water-soluble polymerizable compounds.

  In addition to the polymerizable compound, for example, a compound having a maleimide structure typified below, a compound having a sulfamide structure, a compound having an N-vinylacetamide structure, or the like can also be used.

A water-soluble polymeric compound can be contained individually by 1 type or in combination of 2 or more types.
The content of the polymerizable compound in the ink composition is preferably 3 to 50% by mass, more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass with respect to the total mass of the ink composition.

(Polymerization initiator)
In the mixing step, at least one polymerization initiator is used for mixing. The polymerization initiator is preferably at least one water-soluble polymerization initiator. Here, water-soluble means to dissolve 0.5% by mass or more in distilled water at 25 ° C. The water-soluble polymerization initiator is preferably dissolved at 1% by mass or more in distilled water at 25 ° C., more preferably at least 3% by mass.

  Examples of the water-soluble polymerization initiator include compounds represented by the following general formula (1), compounds described in JP-A-2005-307198, and the like. Especially, it is preferable that it is a water-soluble polymerization initiator represented by following General formula (1) from a viewpoint of adhesiveness and abrasion resistance.

In the general formula (1), m and n each independently represent an integer of 0 or more, and m + n represents an integer of 0 to 3, preferably m is 0 to 3 and n is 0 or 1. , M is 0 or 1, and n is more preferably 0.
Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

  The compound represented by the general formula (1) may be a newly synthesized compound or a commercially available compound. Examples of commercially available compounds represented by the general formula (1) include Irgacure 2959 (m = 0, n = 0: manufactured by BASF Japan).

  The content of the polymerization initiator in the ink composition of the present invention is preferably in the range of 0.1 to 30% by mass in terms of solid content, more preferably in the range of 0.5 to 20% by mass, The range is more preferably 1.0 to 15% by mass, and most preferably 1.0 to 7.0% by mass.

(Water-soluble organic solvent)
In the mixing step, it is preferable to further mix at least one water-soluble organic solvent. By including the water-soluble organic solvent in the black ink composition, it is possible to obtain the effect of preventing drying, moistening, or promoting penetration. In order to prevent drying, the ink adheres to and drys at the ink discharge port of the ejection nozzle and is used as an anti-drying agent to prevent clogging. For drying prevention and wetting, the vapor pressure is lower than that of water. A water-soluble organic solvent is preferred. Further, for penetration promotion, it can be used as a penetration enhancer that enhances ink permeability to paper.

  Examples of water-soluble organic solvents include, for example, alkanediols (polyhydric alcohols) such as glycerin, ethylene glycol, and propylene glycol; sugar alcohols; those having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, and isopropanol Alkyl alcohols; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl Ether, diethylene glycol mono-iso-propyl ether, ethylene glycol -N-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol monoethyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono T-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, Dipropylene glycol mono-iso-propyl ether, tripropylene glycol monomethyl ester Glycol ethers such as such as ether and the like. These can be used individually by 1 type or in combination of 2 or more types.

(Surfactant)
The mixing step preferably includes further mixing at least one surfactant. The surfactant can be used as a surface tension adjusting agent.
As the surface tension modifier, a compound having a structure having both a hydrophilic part and a hydrophobic part in the molecule can be used effectively. Anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic properties Either a surfactant or a betaine surfactant can be used.
In the present invention, a nonionic surfactant is preferable from the viewpoint of suppressing droplet ejection interference of the ink composition, and among them, an acetylene glycol surfactant is more preferable.

  Examples of acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne-4,7. -Alkylene oxide adduct of diol etc. can be mentioned, It is preferable that it is at least 1 sort (s) chosen from this. Examples of commercially available products of these compounds include E series such as Olphine E1010 manufactured by Nissin Chemical Industry Co., Ltd.

In the case where the surfactant (surface tension adjusting agent) is contained in the black ink composition, the surfactant has a surface tension of 20 to 60 mN / in from the viewpoint of satisfactorily discharging the ink composition by an ink jet method. It is preferable to contain the quantity of the range which can be adjusted to m, More preferably, it is 20-45 mN / m from the point of surface tension, More preferably, it is 25-40 mN / m.
The specific amount of the surfactant in the black ink composition of the surfactant is not particularly limited except that the range of the surface tension is preferable, and is preferably 0.1% by mass or more, more preferably. It is 0.1-10 mass%, More preferably, it is 0.2-3 mass%.

(Colloidal silica)
The method for producing a black ink composition of the present invention preferably includes a step of further mixing at least one colloidal silica. The step of mixing colloidal silica may be performed simultaneously with the mixing step or may be performed independently of the mixing step.

When the black ink composition contains colloidal silica, the discharge stability can be improved and a decrease in liquid repellency in the inkjet head member can be suppressed. The effect is particularly great when silicon is used in at least a part of the ink jet head member.
For example, the inclusion of colloidal silica effectively suppresses hydrolysis of the ink component and improves the stability of the ink composition, thereby stopping the ejection of the ink composition on the ink jet recording apparatus for a certain period of time. Even if it is allowed to stand and then discharge is restarted, it is considered that an excellent effect in discharge stability (stand-by recovery performance) can be obtained, and the rubbing resistance of the image can be compatible. Further, it is presumed that colloidal silica is appropriately adsorbed on the surface of the ink jet head member, and the surface erosion due to the ink component is alleviated, thereby preventing the liquid repellency from being lowered.

Colloidal silica is a colloid composed of fine particles of inorganic oxide containing silicon having an average particle size of several hundred nm or less. Silicon dioxide (including hydrates thereof) may be included as a main component, and aluminate may be included as a minor component. Examples of the aluminate that may be contained as a minor component include sodium aluminate and potassium aluminate.
The colloidal silica may contain inorganic salts such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide, and organic salts such as tetramethylammonium hydroxide. These inorganic salts and organic salts act, for example, as colloid stabilizers.

  There is no restriction | limiting in particular as a dispersion medium of colloidal silica, Any of water, an organic solvent, and these mixtures may be sufficient. The organic solvent may be a water-soluble organic solvent or a water-insoluble organic solvent, but is preferably a water-soluble organic solvent. Specifically, methanol, ethanol, isopropyl alcohol, n-propanol etc. can be mentioned.

  There is no restriction | limiting in particular in the manufacturing method of colloidal silica, It can manufacture by the method used normally. For example, it can be produced from aerosil synthesis by thermal decomposition of silicon tetrachloride or water glass. Alternatively, it can also be produced by a liquid phase synthesis method such as hydrolysis of alkoxide (for example, see “Fiber and Industry”, Vol. 60, No. 7 (2004) P376).

Although there is no restriction | limiting in particular as an average particle diameter of the particle | grains contained in the colloidal silica in this invention, Preferably they are 1-25 nm, More preferably, they are 3-20 nm, More preferably, they are 3-15 nm, Especially preferably, 5 nm- 10 nm.
When the average particle size is 25 nm or less, damage (for example, reduction in liquid repellency) due to the ink composition to members constituting the inkjet head, such as a base material, a protective film, and a liquid repellent film, is more effective. Can be suppressed. This can be considered to be because, for example, the average particle diameter is small, the total surface area of the particles is increased, and damage to members constituting the inkjet head is more effectively suppressed. Furthermore, the average particle diameter of the particles is preferably 25 nm or less from the viewpoint of the dischargeability of the ink composition and the abrasive effect of the particles. In addition, when the average particle diameter is 1 nm or more, productivity is improved and colloidal silica with little variation in performance can be obtained.

In the present invention, the average particle diameter of colloidal silica can be measured by a method such as a light scattering method or a laser diffraction method, which is a general measurement of dispersed particles, but in the present invention, as a more direct method, TEM (transmission type) The particle diameter of 300 colloidal silica particles was measured by an electron microscope) imaging method, and the average value was taken as the average particle diameter.
The shape of the colloidal silica is not particularly limited as long as it does not hinder the ejection performance of the ink composition. For example, any of a spherical shape, a long shape, a needle shape, and a bead shape may be used. Among them, the spherical shape is preferable from the viewpoint of ink ejection.

  The colloidal silica that can be used in the present invention may be one produced by the above production method or a commercial product. Specific examples of commercially available products include, for example, Ludox AM, Ludox AS, Ludox LS, Ludox TM, Ludox HS and the like (manufactured by EI Du Pont de Nemours &Co); 20, Snowtex 30, Snowtex 40, Snowtex N, Snowtex C, Snowtex O and the like (manufactured by Nissan Chemical Co., Ltd.); , Nalcoag-ID21 to 64 (above, manufactured by Nalco Chem Co); methanol sol, IPA sol, MEK sol, and toluene sol (above, manufactured by Fuso Chemical Industry); Cataloid-S, Cataloid-F12 0, Cataloid SI-350, Cataloid SI-500, Cataloid SI-30, Cataloid S-20L, Cataloid S-20H, Cataloid S-30L, Cataloid S-30H, Cataloid SI-40, OSCAL-1432 (isopropyl alcohol sol) (Above, manufactured by JGC Catalysts &Chemicals); Adelite (manufactured by Asahi Denka); As beaded colloidal silica, for example, Snowtex ST-UP, PS-S, PS-M, ST-OUP, PS- Examples include commercially available products such as SO and PS-MO (manufactured by Nissan Chemical Co., Ltd.), which are easily available.

  The pH of the commercially available colloidal silica dispersion is often adjusted to be acidic or alkaline. This is because the stable dispersion region of colloidal silica exists on the acidic side or alkaline side. When a commercially available colloidal silica dispersion is added to the ink composition, the pH of the stable dispersion region of colloidal silica and the ink composition It is necessary to add in consideration of the pH of the product.

  Although there is no restriction | limiting in particular in content of the colloidal silica in the ink composition of this invention, Preferably it is 0.005 mass%-0.5 mass% of an ink composition total amount, More preferably, it is 0 of an ink composition total amount. 0.005% by mass to 0.1% by mass, and particularly preferably 0.01% by mass to 0.1% by mass of the total amount of the ink composition. When the content in the ink composition is less than or equal to the above upper limit value, the dischargeability of the ink composition is further improved, and the influence on the inkjet head due to the abrasive effect of the silica particles can be more effectively suppressed. Moreover, the fall of the liquid repellency of an inkjet head member can be suppressed more effectively because it is more than the said lower limit.

  Furthermore, in the ink composition of the present invention, colloidal silica having an average particle size (TEM imaging method) of 3 nm to 25 nm is 0.005 of the total amount of the ink composition from the viewpoint of suppressing the liquid repellency of the ink jet head member and ink ejection properties. The content is preferably from 0.5% to 0.5% by mass, and more preferably from 5% to 0.1% by mass of 3 to 15 nm of colloidal silica based on the total amount of the ink composition.

The content ratio of colloidal silica to the polymerizable compound (colloidal silica / polymerizable compound) in the ink composition of the present invention is preferably 0.0001 to 0.1 on a mass basis, and is preferably 0.001 to 0.00. More preferably, it is 05.
When the content ratio of the colloidal silica to the polymerizable compound is 0.0001 or more, a decrease in liquid repellency of the inkjet head member is more effectively suppressed. Moreover, discharge property improves more because it is 0.1 or less.

(Resin particles)
The black ink composition in the present invention can contain resin particles as necessary. The resin particles may be mixed simultaneously in the mixing step, or may be mixed independently of the mixing step.
The resin particles fix the ink composition, that is, the image, by aggregating or destabilizing the ink and increasing the viscosity of the ink when contacting with a treatment liquid described later or a region on a recording medium dried by the resin particle. It is preferable to have a function of Such resin particles are preferably dispersed in at least one of water and an organic solvent.

Resin particles include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, styrene resins, crosslinked acrylic resins, crosslinked styrene resins, and benzoguanamine resins. A phenol resin, a silicone resin, an epoxy resin, a urethane resin, a paraffin resin, a fluorine resin, or a latex thereof can be used. Preferred examples include acrylic resins, acrylic-styrene resins, styrene resins, cross-linked acrylic resins, and cross-linked styrene resins.
The resin particles can also be used in the form of latex.

The weight average molecular weight of the resin particles is preferably 10,000 or more and 200,000 or less, more preferably 20,000 or more and 200,000 or less.
The average particle size of the resin particles is preferably in the range of 1 nm to 1 μm, more preferably in the range of 1 nm to 200 nm, still more preferably in the range of 1 nm to 100 nm, and particularly preferably in the range of 1 nm to 50 nm.
The glass transition temperature Tg of the resin particles is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 50 ° C. or higher.

The addition amount of the resin particles is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, and further preferably 0.1 to 5% by mass with respect to the black ink composition.
Moreover, there is no restriction | limiting in particular regarding the particle size distribution of a resin microparticle, What has a wide particle size distribution or a thing with a monodispersed particle size distribution may be sufficient. Two or more kinds of resin particles having a monodispersed particle size distribution may be mixed and used.

(Other ingredients)
The black ink composition may further contain various additives as other components, if necessary, in addition to the above components. Various additives may be mixed simultaneously in the mixing step, or may be mixed independently of the mixing step.
Examples of the various additives include, for example, ultraviolet absorbers, antifading agents, antifungal agents, pH adjusters, rust inhibitors, antioxidants, emulsion stabilizers, preservatives, antifoaming agents, viscosity modifiers, and dispersions. Known additives such as stabilizers or chelating agents can be used. The content of these additives may be appropriately determined according to the application, but may be, for example, about 0.02 to 1.00% by mass in the black ink composition.

  Examples of the UV absorber include benzophenone UV absorbers, benzotriazole UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, nickel complex salt UV absorbers, and the like.

  As the anti-fading agent, various organic and metal complex anti-fading agents can be used. Examples of organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, and metal complexes. There are nickel complex, zinc complex and the like.

  Examples of the antifungal agent include, for example, sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, ethyl p-hydroxybenzoate, 1,2-benzisothiazolin-3-one, sodium sorbate, pentachlorophenol Sodium etc. are mentioned.

  The pH adjuster is not particularly limited as long as it can adjust the pH to a desired value without adversely affecting the ink composition to be prepared, and can be appropriately selected according to the purpose. For example, alcohol amines (for example, diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, etc.), alkali metal hydroxides (for example, lithium hydroxide, sodium hydroxide, potassium hydroxide) Etc.), ammonium hydroxide (for example, ammonium hydroxide, quaternary ammonium hydroxide, etc.), phosphonium hydroxide, alkali metal carbonate and the like.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the antioxidant include phenol antioxidants (including hindered phenol antioxidants), amine antioxidants, sulfur antioxidants, phosphorus antioxidants, and the like.

  Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like.

(Physical properties of ink composition)
The surface tension (25 ° C.) of the ink composition in the invention is preferably from 20 mN / m to 60 mN / m. More preferably, it is 20 mN / m or more and 45 mN / m or less, More preferably, it is 25 mN / m or more and 40 mN / m or less.
The surface tension is measured under conditions of 25 ° C. using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

Further, the viscosity at 25 ° C. of the ink composition in the invention is preferably 1.2 mPa · s or more and 15.0 mPa · s or less, more preferably 2 mPa · s or more and less than 13 mPa · s, and further preferably. Is 2.5 mPa · s or more and less than 10 mPa · s.
The viscosity is measured using a VISCOMETER TV-22 (manufactured by TOKI SANGYO CO. LTD) under conditions of 25 ° C.

[Image forming method]
As an image forming method using the black ink composition, for example, an ink application step of applying the black ink composition on a recording medium by an ink jet method, and an aggregate is formed by contacting the ink composition A treatment liquid application step of applying a treatment liquid containing a possible flocculant onto the recording medium, and a curing step of irradiating the ink composition applied on the recording medium with an active energy ray, as necessary. An image forming method including a process can be given.

  By coagulating the components of the ink composition with an aggregating agent contained in the treatment liquid and irradiating this with active energy rays to polymerize and cure the polymerizable compound, it is superior in adhesion to the recording medium and scratch resistance. Images can be formed. Further, the film strength of the image obtained by curing is further improved.

(Ink application process)
In the ink application step, the black ink composition of the present invention described above is applied onto a recording medium by an ink jet method. In this step, the ink composition can be selectively applied onto the recording medium, and a desired image can be formed.

  The inkjet method is not particularly limited, and is a known method, for example, a charge control method that discharges ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses vibration pressure of a piezoelectric element, an electric method An acoustic ink jet system that converts a signal into an acoustic beam, irradiates the ink with ink and ejects the ink using radiation pressure, and a thermal ink jet (bubble jet (registered trademark)) that heats the ink to form bubbles and uses the generated pressure. )) Any method may be used. The ink jet method includes a method of ejecting many low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent inks. The method using is included.

In addition, an ink jet head used in the ink jet method may be an on-demand method or a continuous method. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, a thermal type) Specific examples include an ink jet type, a bubble jet (registered trademark) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.) and a discharge type (for example, a spark jet type). However, any discharge method may be used.
There are no particular restrictions on the ink nozzles used when recording by the ink jet method, and they can be appropriately selected according to the purpose.

  As an ink jet method, a short-type serial head is used, and a shuttle system that performs recording while scanning the head in the width direction of the recording medium, and a line head in which recording elements are arranged corresponding to the entire area of one side of the recording medium There is a line system using. In the line method, an image can be recorded on the entire surface of the recording medium by scanning the recording medium in a direction orthogonal to the arrangement direction of the recording elements, and a carriage system such as a carriage for scanning a short head is not necessary. Further, since complicated scanning control of the carriage movement and the recording medium is not required, and only the recording medium is moved, the recording speed can be increased as compared with the shuttle system. The ink jet recording method of the present invention can be applied to any of these, but generally, when applied to a line system in which no dummy jet is performed, the effect of improving ejection accuracy and image scratch resistance is great.

  The amount of ink droplets ejected from the inkjet head is preferably 0.5 to 6 pl (picoliter), more preferably 1 to 5 pl, and still more preferably 2 to 4 pl from the viewpoint of obtaining a high-definition image. .

(Processing liquid application process)
In the treatment liquid application step, a treatment liquid containing an aggregating agent capable of forming an aggregate by contact with the ink composition is applied to the recording medium, and the treatment liquid is contacted with the ink composition to form an image. In this case, dispersed particles such as resin particles and pigment in the ink composition are aggregated, and the image is fixed on the recording medium. The details and preferred embodiments of each component in the treatment liquid will be described later.

  The treatment liquid can be applied by applying a known method such as a coating method, an ink jet method, or an immersion method. As the coating method, a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or the like can be used. The details of the inkjet method are as described above.

The treatment liquid application step may be provided either before or after the ink application step using the ink composition.
In the present invention, it is preferable to provide an ink application step after applying the treatment liquid in the treatment liquid application step. That is, before applying (discharging) the ink composition to the recording medium by the ink jet method, a processing liquid capable of aggregating the pigment in the ink composition is applied in advance, and the processing liquid applied on the recording medium is applied. An embodiment in which an image is formed by discharging the ink composition so as to come into contact with the ink is preferable. Thereby, inkjet recording can be speeded up, and an image with high density and resolution can be obtained even at high speed recording.

The application amount of the treatment liquid is not particularly limited as long as the ink composition can be aggregated. However, the application amount is preferably such that the application amount of the flocculant is 0.1 g / m ² or more. Especially, the quantity from which the provision amount of a flocculant will be 0.1-1.0 g / m < ² > is preferable, More preferably, it is 0.2-0.8 g / m < ² >. When the amount of the aggregating component is 0.1 g / m ² or more, the agglomeration reaction proceeds favorably, and when it is 1.0 g / m ² or less, the glossiness is not excessively increased.

[Treatment solution]
The treatment liquid contains at least one kind of aggregating agent capable of forming an aggregate by contact with the black ink composition described above, and further contains other components as necessary.

The flocculant in the present invention is capable of aggregating (fixing) components in the ink composition by contacting the ink composition on the recording medium, and functions as, for example, a fixing agent. For example, when the treatment liquid is applied to a recording medium (preferably coated paper), the ink composition further drops and comes into contact with the aggregating agent while the aggregating agent is present on the recording medium. The components in the ink composition can be agglomerated to fix the ink composition component on the recording medium.
Examples of the flocculant include acidic compounds, polyvalent metal salts, and cationic polymers. Among these, an acidic compound is preferable from the viewpoint of cohesiveness of the ink composition component. A flocculant may be used individually by 1 type, or may use 2 or more types together.

-Acidic compounds-
Examples of acidic compounds include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, and tartaric acid. , Lactic acid, sulfonic acid, orthophosphoric acid, metaphosphoric acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, and derivatives of these compounds, etc. Preferably mentioned.

Among these, acidic compounds with high water solubility are preferable. Further, from the viewpoint of fixing the whole ink by reacting with the ink composition component, a trivalent or lower valent acidic compound is preferable, and a divalent or trivalent acidic compound is particularly preferable.
An acidic compound may be used individually by 1 type, and may use 2 or more types together.

  When the treatment liquid contains an acidic compound, the pH (25 ° C.) of the treatment liquid is preferably 0.1 to 6.8, more preferably 0.5 to 6.0, 0.8 More preferably, it is -5.0.

  The content of the acidic compound is preferably 40% by mass or less, more preferably 15 to 40% by mass, and 15 to 35% by mass with respect to the total mass of the treatment liquid. Further preferred. By setting the content of the acidic compound to 40% by mass or less, the components in the ink composition can be more efficiently fixed.

  The treatment liquid preferably contains at least one water-soluble organic solvent in addition to the flocculant. The details of the water-soluble organic solvent are the same as those in the ink composition, and the preferred embodiments are also the same.

  The treatment liquid can further contain other additives as other components within a range not impairing the effects of the present invention. Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, preservatives, anti-fungal agents, pH adjusters, surface tension adjusters, anti-foaming agents. Well-known additives, such as a foaming agent, a viscosity modifier, a dispersing agent, a dispersion stabilizer, a rust preventive agent, a chelating agent, are mentioned.

  In the present invention, an ink application step is provided after the treatment liquid application step, and the treatment liquid on the recording medium is heated and dried after the treatment liquid is applied on the recording medium and before the ink composition is applied. It is preferable to further provide a heat drying step. By heating and drying the treatment liquid in advance before the ink application step, ink colorability such as bleeding prevention is improved, and a visible image with good color density and hue can be recorded.

  Heating and drying can be performed by a known heating means such as a heater, an air blowing means such as a dryer, or a combination of these. As the heating method, for example, a method of applying heat with a heater or the like from the side opposite to the treatment liquid application surface of the recording medium, a method of applying warm air or hot air to the treatment liquid application surface of the recording medium, or an infrared heater was used. The heating method etc. are mentioned, You may heat combining these two or more.

(Heat drying process)
The image forming method of the present invention includes a heating and drying step of heating at least a part of the solvent in the ink composition by heating the ink image formed by applying the ink composition after the ink ejection step. Is preferred. By performing the heat drying treatment, an image having better adhesion and abrasion resistance can be formed by a subsequent curing step.

  The method of heating is not particularly limited, but a non-contact drying method such as a method of heating with a heating element such as a nichrome wire heater, a method of supplying warm air or hot air, a method of heating with a halogen lamp, an infrared lamp, etc. Preferably, it can be mentioned.

(Curing process)
In the image forming method, it is preferable to provide a curing step of irradiating the ink composition applied on the recording medium with active energy rays. The curing step of irradiating the active energy ray is a step of irradiating the ink image formed by applying the ink composition with, for example, ultraviolet rays from an ultraviolet irradiation lamp. Thereby, the monomer component (water-soluble polymerizable compound) in the image can be surely polymerized and cured. At this time, if the ultraviolet irradiation lamp is disposed opposite the recording surface of the recording medium and the entire recording surface is irradiated, the entire image can be cured. The light source for irradiating the active energy ray is not limited to the ultraviolet irradiation lamp, and a halogen lamp, a high-pressure mercury lamp, a laser, an LED, an electron beam irradiation device, or the like can also be employed.
The curing process for irradiating the active energy ray may be installed before or after the heat drying process, as long as it is after the ink application process and the treatment liquid application process. Also good.

The irradiation condition of the active energy ray is not particularly limited as long as the polymerizable compound can be polymerized and cured. For example, the wavelength of the active energy ray is, for example, preferably 200 to 600 nm, more preferably 300 to 450 nm, and further preferably 350 to 420 nm.
The output of the actinic energy ray is preferably at 5000 mJ / cm ² or less, more preferably 10~4000mJ / cm ^2, further preferably 20~3000mJ / cm ^2.

-Recording media-
The image forming method of the present invention records an image on a recording medium.
The recording medium is not particularly limited, and general printing paper mainly composed of cellulose, such as so-called high-quality paper, coated paper, and art paper, used for general offset printing and the like can be used. General printing paper mainly composed of cellulose is relatively slow in ink absorption and drying in image recording by a general ink jet method using water-based ink, and color material movement is likely to occur after droplet ejection, and image quality is likely to deteriorate. However, according to the image forming method using the ink set of the present invention, it is possible to record a high-quality image excellent in color density and hue by suppressing color material movement.

  As the recording medium, commercially available media can be used. For example, “OK Prince Quality” manufactured by Oji Paper Co., Ltd., “Shiraoi” manufactured by Nippon Paper Industries Co., Ltd., and Nippon Paper Industries Co., Ltd. Fine paper (A) such as “New NPI Fine” manufactured by Oji Paper Co., Ltd., “OK Everlight Coat” manufactured by Oji Paper Co., Ltd., and “Aurora S” manufactured by Nippon Paper Industries Co., Ltd., Oji Paper Co., Ltd. Lightweight coated paper (A3) such as “OK Coat L” manufactured by Nippon Paper Industries Co., Ltd. and “Aurora L” manufactured by Nippon Paper Industries Co., Ltd. “OK Top Coat +” manufactured by Oji Paper Co., Ltd. and Nippon Paper Industries Co., Ltd. Coated paper (A2, B2) such as “Aurora Coat” manufactured by Oji Paper Co., Ltd. Art paper (A1) such as “OK Kanto +” manufactured by Oji Paper Co., Ltd. and “Tokuhishi Art” manufactured by Mitsubishi Paper Industries Co., Ltd. Can be mentioned. It is also possible to use various photographic papers for ink jet recording.

Among these, from the viewpoint of obtaining a high-quality image having a large color material movement suppression effect and better color density and hue than before, the water absorption coefficient Ka is preferably 0.05 to 0.5. a recording medium mL ^/ m 2 ^{· ms 1/2,} more preferably recording medium 0.1~0.4mL ^/ m 2 ^{· ms 1/2,} more preferably 0.2-0.3 ml / It is a recording medium of m ² · ms ^1/2 .

  The water absorption coefficient Ka is synonymous with that described in JAPAN TAPPI paper pulp test method No. 51: 2000 (issued by Japan Paper Pulp Technology Association). Specifically, the absorption coefficient Ka is an automatic scanning absorption meter. It is calculated from the difference in the amount of water transferred between the contact time of 100 ms and the contact time of 900 ms using KM500Win (manufactured by Kumagai Riki Co., Ltd.).

  Among the recording media, so-called coated paper used for general offset printing is preferable. The coated paper is obtained by applying a coating material to the surface of high-quality paper, neutral paper, or the like that is mainly surface-treated with cellulose as a main component and is not surface-treated. The coated paper tends to cause quality problems such as image gloss and scratch resistance in image formation by ordinary aqueous inkjet, but in the inkjet recording method of the present invention, gloss unevenness is suppressed and gloss and resistance are reduced. An image having good rubbing properties can be obtained. In particular, it is preferable to use a coated paper having a base paper and a coat layer containing kaolin and / or calcium bicarbonate. More specifically, art paper, coated paper, lightweight coated paper, or finely coated paper is more preferable.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Synthesis of water-insoluble resin (polymer dispersant) P-1)
To a 1000 ml three-necked flask equipped with a stirrer and a condenser, 88 g of methyl ethyl ketone was added and heated to 72 ° C. under a nitrogen atmosphere. To this, 50 g of methyl ethyl ketone was added with 0.85 g of dimethyl-2,2′-azobisisobutyrate and phenoxy. A solution in which 50 g of ethyl methacrylate, 13 g of methacrylic acid, and 37 g of methyl methacrylate were dissolved was dropped over 3 hours. After completion of the dropwise addition, the reaction was further continued for 1 hour, and then a solution prepared by dissolving 0.42 g of dimethyl-2,2′-azobisisobutyrate in 2 g of methyl ethyl ketone was added, heated to 78 ° C. and heated for 4 hours. The obtained reaction solution was reprecipitated twice in an excess amount of hexane, and the precipitated resin was dried to obtain phenoxyethyl methacrylate / methyl methacrylate / methacrylic acid (copolymerization ratio [mass% ratio] = 50/37/13). 96.5 g of copolymer (water-insoluble resin P-1) was obtained.
The composition of the obtained water-insoluble resin P-1 was confirmed by ¹ H-NMR, and the weight average molecular weight (Mw) determined by GPC was 49400. Furthermore, when the acid value of this water-insoluble resin was determined by the method described in JIS standard (JIS K 0070: 1992), it was 84.8 mgKOH / g.

(Synthesis of water-soluble resin (polymer dispersant) P-2)
While isopropanol (187.5 parts) was heated to 80 ° C. under a nitrogen atmosphere, methacrylic acid (216 parts) / benzyl methacrylate (784 parts) / 2,2′-azobis (2-methylbutyronitrile) The liquid mixture (22.05 parts) was dripped over 2 hours. After completion of dropping, the mixture was kept at 80 ° C. for further 4 hours, and then cooled to 25 ° C. By removing the solvent under reduced pressure, a water-soluble resin dispersant P-2 (water-soluble dispersant) having a weight average molecular weight of about 30,000 and an acid value of 140 mgKOH / g was obtained.

(Synthesis of water-soluble resin (polymer dispersant) P-3)
A copolymer (water-soluble) was prepared in the same manner as the water-insoluble resin P-1, except that the copolymerization ratio [mass% ratio] of phenoxyethyl methacrylate / methyl methacrylate / methacrylic acid was 50/11/39). Resin P-3) 96.5 g was obtained.
The composition of the obtained water-soluble resin P-3 was confirmed by ¹ H-NMR, and the weight average molecular weight (Mw) determined by GPC was 48900. The acid value of this polymer was 248.8 mgKOH / g.

(Preparation of carbon black pigment aqueous dispersion CB1)
13 parts of carbon black pigment (NIPEX 170-IQ, manufactured by Degussa), 5.9 parts of the polymer dispersant P-1, 20 parts of methyl ethyl ketone, 8.3 parts of 1 mol / L NaOH aqueous solution, and ion-exchanged water 52 8 parts were mixed and dispersed with a bead mill using 0.1 mmφ zirconia beads for 3 hours.
After removing methyl ethyl ketone at 55 ° C. under reduced pressure and removing a part of water in the obtained dispersion, using a high-speed centrifugal cooler 7550 (manufactured by Kubota Seisakusho), using a 50 mL centrifuge, Centrifugation was performed at 8000 rpm for 30 minutes, and the supernatant liquid other than the precipitate was collected. Thereafter, the pigment concentration was determined from the absorbance spectrum, and ion-exchanged water was added to obtain a carbon black pigment aqueous dispersion CB1 as a dispersion of resin-coated pigment particles (encapsulated pigment) having a pigment concentration of 15% by mass.
When the volume average particle size was measured by a dynamic light scattering method using Nanotrac particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.), it was 87 nm.

(Preparation of carbon black pigment aqueous dispersion CB2)
Pigment dispersion 2 was obtained using water-soluble resin P-2 as follows.
13.6 parts of carbon black pigment, 6.2 parts of the dispersing agent P-2, 9.3 parts of 1 mol / L NaOH aqueous solution, and 70.9 parts of ion-exchanged water were mixed, and 0. Dispersion was performed for 3 hours using 1 mmφ zirconia beads.
Thereafter, 0.87 part of trimethylolpropane triglycidyl ether and 0.38 part of boric acid were added and reacted at 60 ° C. for 6 hours, followed by cooling. Further, using a high-speed centrifugal cooler 7550 (manufactured by Kubota Corporation), Centrifugation was performed at 8000 rpm for 30 minutes using a 50 mL centrifuge, and the supernatant other than the precipitate was collected. Thereafter, the pigment concentration was determined from the absorbance spectrum, and ion-exchanged water was added to obtain a pigment dispersion 2 as a dispersion of resin-coated pigment particles having a carbon black concentration of 13% by mass.
Similarly, the volume average particle diameter was measured and found to be 92 nm.

(Preparation of carbon black pigment aqueous dispersion CB3)
11.3 parts of carbon black pigment, 5.1 parts of the water-soluble dispersant P-3, 21 parts of a 1 mol / L NaOH aqueous solution, and 62.6 parts of ion-exchanged water were mixed, and 0. Dispersion was performed for 3 hours using 1 mmφ zirconia beads.
The obtained dispersion was centrifuged at 8000 rpm for 30 minutes using a high-speed centrifugal cooler 7550 (manufactured by Kubota Seisakusho), and the supernatant liquid other than the precipitate was collected. Thereafter, the pigment concentration was determined from the absorbance spectrum, and ion-exchanged water was added to obtain a pigment dispersion 3 having a carbon black concentration of 10.0% by mass.
Similarly, the volume average particle diameter was measured and found to be 90 nm.

(Preparation of Colored Pigment Aqueous Dispersion C1)
A colored pigment aqueous dispersion C1 was obtained in the same manner as described above except that in the preparation of the aqueous carbon black pigment dispersion 1, Pigment Blue 15: 3 was used instead of the carbon black pigment.
Similarly, the volume average particle diameter was measured and found to be 93 nm.

(Preparation of colored pigment aqueous dispersion M1)
A colored pigment aqueous dispersion M1 was obtained in the same manner as described above except that in the preparation of the colored pigment dispersion C1, Pigment Red 122 was used instead of Pigment Blue 15: 3.
Similarly, the volume average particle diameter was measured and found to be 78 nm.

(Preparation of colored pigment aqueous dispersion Y1)
Colored pigment aqueous dispersion Y1 was obtained in the same manner as described above except that in the preparation of Pigment Dispersion 1, Pigment Yellow 74 was used instead of Pigment Blue 15: 3.
Similarly, the volume average particle diameter was measured and found to be 95 nm.

(Synthesis of polymerizable compound 2)
To a 1 L three-necked flask equipped with a stirrer was added 40.0 g (182 mmol) of 4,7,10-trioxa-1,13-tridecanediamine, 37.8 g (450 mmol) of sodium bicarbonate, 100 g of water, and 300 g of tetrahydrofuran. In an ice bath, 35.2 g (389 mmol) of acrylic acid chloride was added dropwise over 20 minutes. After dropping, the mixture was stirred at room temperature for 5 hours, and then tetrahydrofuran was distilled off from the obtained reaction mixture under reduced pressure. Next, the aqueous layer was extracted four times with 200 ml of ethyl acetate, and the obtained organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off under reduced pressure to obtain 35.0 g of the target polymerizable compound 2 solid. (107 mmol, 59% yield).

<Example 1>
(Preparation of black ink composition Bk-1)
Using the carbon black pigment aqueous dispersion CB1 obtained above, the colored pigment aqueous dispersion C1to, the polymerizable compound 1, and colloidal silica (Snowtex XS, average particle size 5 nm, manufactured by Nissan Chemical Industries, Ltd.) Each component was mixed so as to have the following ink composition. This was packed in a plastic disposable syringe and filtered through a PVDF 5 μm filter (Millex-SV, diameter 25 mm, manufactured by Millipore) to prepare a black ink composition Bk-1.

~ Ink composition ~
-Carbon black pigment aqueous dispersion CB1 ... 17.3%
-Colored pigment aqueous dispersion C1 2.7%
・ Polymerizable compound 2 ... 19%
・ Diethylene glycol monoethyl ether ・ ・ ・ 1%
(DEGmEE, manufactured by Wako Pure Chemical Industries, Ltd.)
・ Colloidal silica (solid content) 0.05%
(Snowtex XS, solid concentration 20%, manufactured by Nissan Chemical Industries, Ltd.)
・ Orphine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) ・ ・ ・ 1%
・ Irgacure 2959 (BASF Japan) 2.9%
・ Ion-exchanged water ・ ・ ・ Remaining amount (added to 100% by mass in total)

<Examples 2 to 6>
In Example 1, the black ink composition Bk was used in the same manner as in Example 1 except that the types and addition amounts of the carbon black pigment aqueous dispersion and the colored pigment aqueous dispersion were changed so as to have the formulation shown in Table 1. -2 to 6 were prepared respectively.
In Table 1, the addition amounts of the carbon black pigment and the color pigment each mean the solid content.

<Comparative Example 1>
In Example 1, the black ink composition Bk-7 was prepared in the same manner as in Example 1 except that the addition amount of the carbon black pigment aqueous dispersion CB1 was changed to 20% without using the color pigment aqueous dispersion. Prepared.

<Preparation of treatment liquid 1>
The component of the following composition was mixed and the processing liquid 1 was prepared. The viscosity, surface tension, and pH (25 ° C.) of the treatment liquid 1 were a viscosity of 2.5 mPa · s, a surface tension of 40 mN / m, and a pH of 1.0. The surface tension was measured using a fully automatic surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd., and the viscosity was measured using DV-III Ultra CP manufactured by Brookfield Engineering. The pH was measured using a PH meter HM-30R manufactured by Toa DKK Co., Ltd.
~ Composition of treatment liquid 1 ~
・ Malonic acid (Wako Pure Chemical Industries, Ltd.) 25.0%
・ Diethylene glycol monomethyl ether 20.0%
(Wako Pure Chemical Industries, Ltd.)
・ Emulgen P109 ・ ・ ・ 1.0%
(Nonionic surfactant manufactured by Kao Corporation)
・ Ion-exchanged water: 54.0%

<Image formation and evaluation>
An ink jet head provided with a silicon nozzle plate was prepared, and the black ink composition obtained above was refilled in a storage tank connected thereto. The silicon nozzle plate is previously provided with a liquid repellent film using a fluorinated alkylsilane compound. “OK Top Coat +” (basis weight 104.7 g / m ² ) manufactured by Oji Paper Co., Ltd. as a recording medium is cut into A5 size and fixed on a stage that can move in a predetermined linear direction at 500 mm / second. The stage temperature was kept at 30 ° C. The treatment liquid 1 obtained above was applied to this with a bar coater so as to have a thickness of about 1.2 μm, and was dried at 50 ° C. for 2 seconds immediately after the application.
Thereafter, the inkjet head is fixedly arranged so that the direction of the line head in which the nozzles are arranged (main scanning direction) is inclined by 75.7 degrees with respect to the direction orthogonal to the moving direction (sub-scanning direction) of the stage, and recording A solid image is obtained by ejecting ink over the entire surface of the recording medium in a line system under the ejection conditions of an ink droplet amount of 2.8 pL, an ejection frequency of 25.5 kHz, a resolution of 1200 dpi × 1200 dpi while moving the medium at a constant speed in the sub-scanning direction. It was. After the image was recorded, while being heated from the back side (back side) of the ink landing surface with an infrared heater, the recording surface was dried by applying warm air of 120 ° C. and 5 m / sec for 15 seconds. After the image was dried, UV light (metal halide lamp, maximum irradiation wavelength 365 nm, manufactured by Eye Graphics Co., Ltd.) was irradiated so as to obtain an integrated irradiation amount of 3 J / cm ² to cure the image to obtain a print sample.

[Adhesion evaluation]
The print sample obtained above was left in an environment of 25 ° C. and 50% RH for 24 hours. A 3 cm long cello tape (registered trademark) (LP-12, manufactured by Nichiban Co., Ltd.) was applied to the solid image surface of the printed sample after being left, and the cello tape (registered trademark) was peeled off after 5 seconds. Then, the cellotape (registered trademark) peeled off from the sample was visually observed and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

~Evaluation criteria~
A: There was no color adhesion to the tape, and no deterioration of the solid image of the sample was observed.
B: Although the color adhered to the tape, no deterioration of the solid image of the sample was observed.
C: Color adhered to the tape, and deterioration of the solid image of the sample was also observed.
D: Color adhered to more than half the area of the tape, and the solid image of the sample dropped out.
* D is a level that is problematic in practice.

[Evaluation of neglectability] (Discharge stability when the ink composition is stopped on the ink jet recording apparatus and allowed to stand for a certain period of time, and then the ejection is resumed)
Using Fuji Photo Film Co., Ltd.'s photo photographic finishing Pro as the recording medium, moving the stage holding the recording medium at 248 mm / min, ink droplet volume 3.4 pL, ejection frequency 10 kHz, nozzle array direction x transport direction Print samples (line images) were prepared by discharging 96 ink droplets per nozzle at 75 × 1200 dpi in parallel with the transport direction. The other detailed conditions for image formation were the same as those for the above-described solid image formation.
Next, the obtained print sample was visually observed to confirm that ink was ejected from all nozzles.
After forming this line image, the head was left as it was for a predetermined time, then a new recording medium was pasted, and ink was again ejected under the same conditions as above to produce a print sample (line image). . The obtained print sample (line image) was visually observed, and after leaving for a predetermined time, 2000 discharges were performed, and the stand recovery property was evaluated by the maximum stand time in which all 96 nozzles could be discharged. The longer the standing time during which no ejection failure occurred, the better the ejection performance, and the evaluation was based on the following evaluation criteria. The evaluation results are shown in Table 1.

~Evaluation criteria~
A: The maximum standing time was 45 minutes or more.
B: The maximum standing time was 30 or more and less than 45 minutes.
C: The maximum standing time was 20 minutes or more and less than 30 minutes.
D: The maximum standing time was less than 20 minutes.
* D is a level that is problematic in practice.

From Table 1, it can be seen that an image having excellent adhesion and abrasion resistance can be formed by forming an image using the black ink composition of the present invention.
Further, since colloidal silica is included, even when an ink jet head provided with a silicon nozzle plate is used, a decrease in liquid repellency in the silicon nozzle plate is suppressed.

Claims (8)

Obtaining an aqueous dispersion of carbon black pigment containing carbon black pigment as a pigment;
Obtaining a colored pigment aqueous dispersion containing as a pigment at least one color pigment selected from the group consisting of a magenta pigment, a cyan pigment and a yellow pigment;
Mixing the carbon black pigment aqueous dispersion, the colored pigment aqueous dispersion, the water-soluble polymerizable compound, and the polymerization initiator;
A method for producing a black ink composition for ink jet recording comprising:   2. The black ink composition according to claim 1, wherein at least one of the carbon black pigment aqueous dispersion and the colored pigment aqueous dispersion contains a pigment having a surface coated with a water-insoluble resin having an acidic group. Manufacturing method.   3. The method for producing a black ink composition according to claim 1, wherein the color pigment aqueous dispersion contains at least one color pigment selected from the group consisting of a magenta pigment and a cyan pigment. The said polymerization initiator is a manufacturing method of the black-type ink composition of any one of Claims 1-3 which is a compound represented by following General formula (1).

(In the formula, m and n each independently represent an integer of 0 or more, and m + n represents an integer of 0 to 3)   The method for producing a black ink composition according to any one of claims 1 to 4, further comprising mixing colloidal silica.   The volume average secondary particle diameter of the pigment contained in at least one selected from the group consisting of the carbon black pigment aqueous dispersion and the colored pigment aqueous dispersion is 40 nm to 150 nm. A method for producing the black ink composition according to claim 1.   The method for producing a black ink composition according to any one of claims 1 to 6, further comprising mixing an acetylene glycol surfactant.   The black ink composition manufactured with the manufacturing method of any one of Claims 1-7.