JP2015183088A - Ink set, ink cartridge set, recording device, and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink set that inhibits an image of inks of multiple colors from peeling off an impermeable recording medium.SOLUTION: An ink set comprises aqueous inks of multiple colors different from each other. Each ink comprises a colorant, polymer particles, water, and an aqueous organic solvent; has a static surface tension of 28 mN/m or less; and, when examined for dynamic surface tension by the maximum bubble pressure method, has a width of variations in dynamic surface tension, for a period from 1 msec after to 1 sec after, in the range from 0.2 mN/m to 2.0 mN/m inclusive. A difference in the width of variations in dynamic surface tension between the aqueous inks of multiple colors is in the range from 0 mN/m to 1.0 mN/m inclusive.

Description

  The present invention relates to an ink set, an ink cartridge set, a recording apparatus, and a recording method.

  Patent Document 1 states that “the pigment dispersion resin is water-soluble, and the mass ratio of the pigment dispersion resin to the pigment (resin content / pigment content) is 0.3 to 0.6. The dynamic surface tension is 46 mN / m when the mass ratio (free resin amount / pigment content) of free resin and pigment not adhered to the pigment is 0 to 0.1 and the surface life is 10 ms. The above-mentioned “ink-jet recording liquid” is disclosed.

  Patent Document 2 states that “it has the property of being cured by irradiation with light such as ultraviolet rays and electron beams, and the dynamic surface tension value at 80 milliseconds is greater than 28 mN / m, and the dynamic value at 80 milliseconds is dynamic. “Non-aqueous ink for inkjet use” in which a value obtained by subtracting a dynamic surface tension value at 1000 milliseconds from a surface tension value is smaller than 8 mN / m is disclosed.

  Patent Document 3 states that “the dynamic surface tension γ30 after 30 seconds by the plate method is in the range of 25 mN / m to 35 mN / m and the difference from the dynamic surface tension γ600 after 600 seconds is γ600−. An inkjet ink satisfying γ30 ≦ −1 mN / m ”is disclosed.

JP 2011-219646 A JP 2006-219625 A JP 2013-112801 A

  The subject of this invention is providing the ink set which suppresses peeling of the image by multiple colors of ink with respect to a non-permeable recording medium.

  The above problem is solved by the following means.

The invention according to claim 1
Contains a colorant, polymer particles, water, and an aqueous organic solvent, has a static surface tension of 28 mN / m or less, and dynamic surface tension measured by the maximum bubble pressure method is dynamic from 1 msec to 1 sec. The variation range of the surface tension is 0.2 mN / m or more and 2.0 mN / m or less, and there are a plurality of water-based inks having different colors.
An ink set in which a difference in the fluctuation range of the dynamic surface tension between the water-based inks of the plurality of colors is 0 mN / m or more and 1.0 mN / m or less.

The invention according to claim 2
2. The dynamic surface tension after 1 msec in the multi-color water-based ink is 32 mN / m or less, and the dynamic surface tension after 1 sec in the multi-color water-based ink is 30 mN / m or less. The ink set described in 1.

The invention according to claim 3
An ink cartridge set containing each water-based ink of the ink set according to claim 1.

The invention according to claim 4
A recording apparatus comprising: an ejection head that ejects each aqueous ink of the ink set according to claim 1 or 2 onto a non-permeable recording medium.

The invention according to claim 5
The recording apparatus according to claim 4, further comprising a drying device that dries each of the water-based inks ejected on the non-permeable recording medium.

The invention according to claim 6
A recording method comprising a discharge step of discharging each water-based ink of the ink set according to claim 1 or 2 onto a non-permeable recording medium.

The invention according to claim 7 provides:
The recording method according to claim 6, further comprising a drying step of drying each water-based ink ejected on the non-permeable recording medium.

According to the first aspect of the invention, when the static surface tension of the water-based ink exceeds 28 mN / m, when the fluctuation range of the dynamic surface tension of the water-based ink exceeds 2.0 mN / m, or a plurality of colors Compared to the case where the difference in the dynamic surface tension fluctuation range in water-based ink exceeds 1.0 mN / m, there is an ink set that suppresses image peeling due to a plurality of colors of ink on a non-permeable recording medium. Provided.
According to the invention of claim 2, when the dynamic surface tension after 1 msec of the water-based ink exceeds 32 mN / m, or when the dynamic surface tension after 1 sec of the water-based ink exceeds 30 mN / m. In comparison, an ink set that suppresses peeling of an image due to a plurality of colors of ink is provided for a non-permeable recording medium.

  According to the invention of claim 3, when the static surface tension of the water-based ink exceeds 28 mN / m, when the fluctuation range of the dynamic surface tension of the water-based ink exceeds 2.0 mN / m, or a plurality of colors An ink cartridge set that suppresses peeling of an image due to a plurality of colors on a non-permeable recording medium as compared with a case where the difference in the fluctuation range of the dynamic surface tension between water-based inks exceeds 1.0 mN / m. Is provided.

According to the invention of claim 4, when the static surface tension of the water-based ink exceeds 28 mN / m, when the fluctuation range of the dynamic surface tension of the water-based ink exceeds 2.0 mN / m, or a plurality of colors A recording apparatus that suppresses peeling of an image due to a plurality of colors of ink on a non-penetrable recording medium as compared with a case where the difference in fluctuation range of dynamic surface tension between water-based inks exceeds 1.0 mN / m. Provided.
According to the invention of claim 5, there is provided a recording apparatus that realizes high-speed recording while suppressing peeling of an image due to a plurality of colors of ink on a non-permeable recording medium as compared with a case where a drying apparatus is not provided. Provided.

According to the invention of claim 6, when the static surface tension of the water-based ink exceeds 28 mN / m, when the fluctuation range of the dynamic surface tension of the water-based ink exceeds 2.0 mN / m, or a plurality of colors There is a recording method that suppresses peeling of an image due to a plurality of color inks on a non-permeable recording medium as compared with the case where the difference in the fluctuation range of the dynamic surface tension between water-based inks exceeds 1.0 mN / m. Provided.
According to the invention of claim 7, a recording method that realizes high-speed recording while suppressing peeling of an image due to a plurality of colors of ink on a non-permeable recording medium as compared with a case without a drying step. Is provided.

1 is a schematic configuration diagram illustrating a recording apparatus according to an embodiment.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

(Ink set)
The ink set according to the present embodiment includes a plurality of water-based inks (hereinafter also simply referred to as “inks”) that include a colorant, polymer particles, water, and an aqueous organic solvent and have different colors. Each ink has a static surface tension of 28 mN / m or less. When the dynamic surface tension is measured by the maximum bubble pressure method, the fluctuation range of the dynamic surface tension from 1 msec to 1 sec (hereinafter simply referred to as “dynamic”). The fluctuation range of the surface tension ”is also 0.2 mN / m or more and 2.0 mN / m or less.
And the difference of the fluctuation | variation width | variety of the mutual dynamic surface tension in the ink of several colors is 0 mN / m or more and 1.0 mN / m or less.

Here, when ink is ejected onto a non-penetrable recording medium, the ink that has landed on the recording medium does not penetrate or hardly penetrates the recording medium. Remains. For this reason, it is difficult for the ink to dry on the non-permeable recording medium, and if a roller member (a cooling roller, a conveyance roller, etc.) comes into contact with the image recording surface immediately after the image is recorded with the ink, the image may be peeled off. is there. In particular, when an image with a plurality of colors of ink is recorded, image peeling occurs remarkably. For this reason, there is a demand for an ink that has a characteristic of quickly drying on a non-permeable recording medium as a characteristic of each ink of a plurality of colors.
In addition, in order to quickly dry the ink on the non-permeable recording medium, it is also known to carry out evaporation drying (thermal drying) of the ink by heating, but this causes an increase in energy consumption and equipment. Become.

Therefore, in the ink set according to the present embodiment, the fluctuation range of the dynamic surface tension of the inks of the plurality of colors is set within the above range, and the fluctuation of the dynamic surface tension of each of the inks of the plurality of colors is changed. The difference in width is also in the above range.
The ink having the fluctuation range of the static surface tension and the dynamic surface tension within the above ranges is an ink in which the fluctuation range of the dynamic surface tension is reduced while the static surface tension is reduced. That is, this ink indicates an ink having a property of rapidly spreading on a non-permeable recording medium. Since this ink quickly wets and spreads on the non-permeable recording medium, rapid drying is realized even when the ink does not penetrate or hardly penetrates the recording medium. In addition to this, if the difference in the dynamic surface tension variation width of the plurality of colors of ink having this property is reduced to the above range, the difference in drying speed between the plurality of colors of ink is reduced. That is, in an image using a plurality of colors of ink, all the inks are dried to the same extent. For this reason, even if the image recording surface is in contact with the roller member immediately after the image recording with the ink, peeling of the image is suppressed.

From the above, in the ink set according to the present embodiment, peeling of an image due to a plurality of colors of ink is suppressed even on an impermeable recording medium. However, the above-described reason for suppressing image peeling is an estimation effect and is not interpreted in any way.

Examples of impermeable recording media include coated paper and resin films. Specifically, the non-permeable recording medium means a recording medium having a maximum ink absorption amount of 15 ml / m ² or less within a contact time of 500 ms as measured by a dynamic scanning absorption meter.

In the ink set according to the present embodiment, the static surface tension of each ink is 28 mN / m or less, and preferably 21 mN / m or more and 28 mN / m or less from the viewpoint of ejection stability.
The static surface tension is a value measured using a Wilhelmy surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) in an environment of 23 ° C. and 55% RH.

  The fluctuation range of the dynamic surface tension of each ink is 0.2 mN / m or more and 2.0 mN / m or less, and preferably 0.2 mN / m or more and 1.8 mN / m or less from the viewpoint of image peeling suppression. Preferably they are 0.2 mN / m or more and 1.5 mN / m or less. The fluctuation range of the dynamic surface tension is a difference between the value of the dynamic surface tension after 1 msec and the value of the dynamic surface tension after 1 sec.

The dynamic surface tension after 1 msec in each ink is preferably 32 mN / m or less, more preferably 21 mN / m or more and 30 mN / m or less, and still more preferably 22 mN / m or more and 28 mN / m or less, from the viewpoint of suppressing image peeling. It is.
On the other hand, the dynamic surface tension after 1 sec in each ink is preferably 30 mN / m or less, more preferably 21 mN / m or more and 28 mN / m or less, and further preferably 22 mN / m or more and 28 mN / m or less from the viewpoint of suppressing image peeling. m or less.

  The difference in the fluctuation range of the dynamic surface tension of each ink is 0 mN / m or more and 1.0 mN / m or less, and preferably 0 mN / m or more and 0.9 mN / m or less from the viewpoint of image peeling suppression. Preferably they are 0 mN / m or more and 0.5 mN / m or less. The difference in the dynamic surface tension fluctuation range is an absolute value.

The dynamic surface tension is a value measured in an environment of 23 ° C. and 55% RH using a maximum bubble pressure method dynamic surface tension meter MPTC (manufactured by LAUDA).
The value of the dynamic surface tension after 1 msec is the value of the dynamic surface tension when the maximum bubble pressure is reached in 1 msec after a new interface is formed at the capillary tip. However, in the case of the dynamic surface tension after 1 msec, the measurement limit displayed by the maximum bubble pressure method dynamic surface tension meter may be expressed as the dynamic surface tension after 0 msec. In this case, the value of the dynamic surface tension after 0 msec is adopted as the value of the dynamic surface tension after 1 msec.
On the other hand, the value of the dynamic surface tension after 1 sec is the value of the dynamic surface tension when the maximum bubble pressure is reached in 1 sec after a new interface is formed at the capillary tip. However, when the measurement limit of the maximum bubble pressure method dynamic surface tension meter is the dynamic surface tension after less than 1 sec, the value of the dynamic surface tension at the measurement limit is adopted as the value of the dynamic surface tension after 1 sec. . This is because the dynamic surface tension can be determined to be in the stable region if the value is the dynamic surface tension at the measurement limit.

  Here, in each ink, in order to set the static surface tension, the fluctuation range of the dynamic surface tension, the difference in the fluctuation range of the dynamic surface tension, and the dynamic surface tension after 1 msec or 1 sec, within the above ranges, Each ink may contain a surfactant together with, for example, a colorant, polymer particles, water, and an aqueous organic solvent. That is, the static surface tension, the dynamic surface tension fluctuation range, the difference in the dynamic surface tension fluctuation range, and the dynamic surface tension after 1 msec or 1 sec are adjusted according to the type and amount of the surfactant. Is good.

  Examples of the surfactant include a surfactant having an HLB (hydrophilic group / hydrophobic group balance “Hydrophile-Lipophile Balance”) of 14 or less. For example, by adjusting the amount of the surfactant having an HLB of 14 or less, the target static surface tension can be easily adjusted. Further, among the surfactants having an HLB of 14 or less, when a plurality of surfactants having different HLBs are used, the target dynamic surface tension can be easily adjusted. Specifically, for example, when a surfactant having an HLB of 11 or more and 14 or less and a surfactant having an HLB of 4 or more and less than 11 are used, the target dynamic surface tension can be easily adjusted.

The HLB (hydrophilic group / hydrophobic group balance “Hydrophile-Lipophile Balance”) is defined by the following formula (Griffin method).
・ HLB = 20 × (sum of formula weight of hydrophilic part / molecular weight)

  Examples of such a surfactant include at least one selected from the group consisting of an ethylene oxide adduct of acetylene glycol and a polyether-modified silicone.

The ethylene oxide adduct of acetylene glycol is, for example, an —O— (CH ₂ CH ₂ O) _n —H structure in which ethylene oxide is added to at least one hydroxyl group of acetylene glycol (for example, n is 1 to 30). A compound having an integer)
Examples of commercially available products of ethylene oxide adducts of acetylene glycol (the values in parentheses indicate catalog values of HLB) include, for example, Olphine E1004 (7-9), Olphine E1010 (13-14), Olphine EXP. 4001 (8-11), Olfine EXP. 4123 (11-14), Olfine EXP. 4300 (10-13), Surfinol 104H (4), Surfinol 420 (4), Surfinol 440 (4), Dinol 604 (8) [Nippon Chemical Industry Co., Ltd.] and the like.
The content of the ethylene oxide adduct of acetylene glycol is, for example, preferably 0.01% by mass to 10% by mass and preferably 0.1% by mass to 5% by mass with respect to the ink.

The polyether-modified silicone is, for example, a compound in which a polyether group is bonded to a silicone chain (polysiloxane main chain) in a graft form or a block form. Examples of the polyether group include a polyoxyethylene group and a polyoxypropylene group. The polyether group may be, for example, a polyoxyalkylene group in which an oxyethylene group and an oxypropylene group are added in a block form or randomly.
As commercial products of polyether-modified silicone (the numbers in parentheses indicate catalog values of HLB), Silface SAG002 (12), Silface SAG503A (11), Silface SAG005 (7) [more, Nissin Chemical Industry Co., Ltd.].
The content of the polyether-modified silicone is, for example, from 0.01% by mass to 5% by mass with respect to the ink, and preferably from 0.05% by mass to 1% by mass.

  Here, in the ink set according to the present embodiment, the plurality of colors of ink are, for example, at least two kinds of multiple colors selected from black ink, cyan ink, magenta ink, yellow ink, and intermediate color inks other than these colors. Consists of ink. The ink set is composed of inks of a plurality of colors other than black (for example, at least two kinds of inks selected from cyan ink, magenta ink, yellow ink, and intermediate color inks other than these colors). Preferably, the ink is composed of three colors of ink, cyan ink, magenta ink, and yellow ink.

  Next, the composition and characteristics of each ink in the ink set according to the present embodiment will be described in detail.

  Each ink of the ink set includes colorants of different colors. Each ink contains polymer particles, water, and an aqueous organic solvent in addition to the colorant.

The colorant will be described.
Examples of the colorant include pigments. Examples of the pigment include organic pigments and inorganic pigments.

  Specific examples of black pigments (black pigments) include Raven7000, Raven5750, Raven5250, Raven5000 ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1200, Raven1190, Raven1190, Raven1190, Raven1190 ), Regal 400R, Regal 330R, Regal 660R, Mogu L, Black Pearls L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Mo arch 1400 (above 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 S160, 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 (manufactured by Degussa), No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like, but are not limited thereto.

Specific examples of the cyan pigment include C.I. I. Pigment Blue-1, -2, -3, -15, -15: 1, -15: 2, -15: 3, -15: 4, -16, -22, -60, and the like. It is not limited.
Specific examples of the magenta color pigment include C.I. I. Pigment Red-5, -7, -12, -48, -48: 1, -57, -112, -122, -123, -146, -168, -177, -184, -202, C.I. I. Pigment Violet-19 etc. are mentioned, However, It is not limited to these.
Specific examples of yellow pigments include C.I. I. Pigment Yellow-1, -2, -3, -12, -13, -14, -16, -17, -73, -74, -75, -83, -93, -95, -97, -98, -114, -128, -129, -138, -151, -154, -180, and the like, but are not limited thereto.

  Here, when a pigment is used as the colorant, it is preferable to use a pigment dispersant together. Examples of the pigment dispersant used include a polymer dispersant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  As the polymer dispersant, a polymer having a hydrophilic structure portion and a hydrophobic structure portion is preferably used. As the polymer having a hydrophilic structure part and a hydrophobic structure part, for example, a condensation polymer and an addition polymer are used. Examples of the condensation polymer include known polyester dispersants. Examples of the addition polymer include addition polymers of monomers having an α, β-ethylenically unsaturated group. By copolymerizing a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group and a monomer having an α, β-ethylenically unsaturated group having a hydrophobic group, A molecular dispersant is obtained. A homopolymer of a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group is also used.

  Monomers having an α, β-ethylenically unsaturated group having a hydrophilic group include monomers having a carboxyl group, a sulfonic acid group, a hydroxyl group, a phosphoric acid group, such as acrylic acid, methacrylic acid, and croton. Acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, vinyl sulfonic acid, styrene sulfonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bis Examples include methacryloxyethyl phosphate, methacryloxyethyl phenyl acid phosphate, ethylene glycol dimethacrylate, and diethylene glycol dimethacrylate.

  Examples of the monomer having an α, β-ethylenically unsaturated group having a hydrophobic group include styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, and alkyl acrylate esters. Methacrylic acid alkyl ester, methacrylic acid phenyl ester, methacrylic acid cycloalkyl ester, crotonic acid alkyl ester, itaconic acid dialkyl ester, maleic acid dialkyl ester and the like.

  Examples of preferred copolymers as the polymer dispersant include styrene-styrene sulfonic acid copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer, vinyl naphthalene- Maleic acid copolymer, vinyl naphthalene-methacrylic acid copolymer, vinyl naphthalene-acrylic acid copolymer, alkyl acrylate ester-acrylic acid copolymer, alkyl methacrylate ester-methacrylic acid copolymer, styrene-methacrylic acid Examples include alkyl ester-methacrylic acid copolymer, styrene-acrylic acid alkyl ester-acrylic acid copolymer, styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, and styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer. It is done. Moreover, you may copolymerize the monomer which has a polyoxyethylene group and a hydroxyl group with these polymers.

  The weight average molecular weight of the polymer dispersant is preferably, for example, 2000 or more and 50000 or less.

  These polymer dispersants may be used alone or in combination of two or more. The content of the polymer dispersant varies greatly depending on the pigment and cannot be generally stated, but it is preferably 0.1% by mass or more and 100% by mass or less based on the pigment.

Examples of the pigment include pigments that are self-dispersed in water (hereinafter referred to as self-dispersing pigments).
The self-dispersing pigment refers to a pigment that has a water-solubilizing group on the pigment surface and disperses in water without the presence of a polymer dispersant. The self-dispersing pigment can be obtained, for example, by subjecting the pigment to surface modification treatment such as acid / base treatment, coupling agent treatment, polymer graft treatment, plasma treatment, oxidation / reduction treatment, and the like.

  As self-dispersing pigments, in addition to pigments that have been surface-modified to the above pigments, Cab-o-jet-200, Cab-o-jet-300, Cab-o-jet-400 manufactured by Cabot Corporation. IJX-157, IJX-253, IJX-266, IJX-273, IJX-444, IJX-55, Cab-o-jet-250C, Cab-o-jet-260M, Cab-o-jet-270Y, Cab -O-jet-450C, Cab-o-jet-465M, Cab-o-jet-470Y, Cab-o-jet-480M, Microjet Black CW-1, CW-2 manufactured by Orient Chemical Co., etc. Examples include dispersed pigments.

  The self-dispersing pigment is preferably a pigment having at least sulfonic acid, sulfonate, carboxylic acid, or carboxylate as a functional group on the surface thereof. More preferably, it is a pigment having at least a carboxylic acid or a carboxylate as a functional group on the surface.

Here, examples of the pigment include a pigment coated with a resin. This is called a microcapsule pigment, and there are commercially available microcapsule pigments such as those manufactured by DIC Chemical Industry Co., Ltd. and Toyo Ink Co., Ltd. In addition, it is not restricted to a commercially available microcapsule pigment, You may use the microcapsule pigment produced according to the objective.
Examples of the pigment also include a resin dispersion type pigment in which a polymer compound is physically adsorbed or chemically bonded to the pigment.
In addition to black, cyan, magenta, and yellow, the pigments include specific color pigments such as red, green, blue, brown, and white, metallic luster pigments such as gold and silver, and colorless or light-colored constitutions. Examples include pigments and plastic pigments.
Examples of the pigment include particles in which silica, alumina, polymer beads or the like are used as a core, and a dye or pigment is fixed on the surface thereof, an insoluble lake of the dye, a colored emulsion, a colored latex, or the like.

  As colorants, in addition to pigments, other hydrophilic anionic dyes, direct dyes, cationic dyes, reactive dyes, polymer dyes and oil-soluble dyes, wax powders and resin powders colored with dyes And emulsions, fluorescent dyes and fluorescent pigments.

The volume average particle diameter of the colorant is, for example, 10 nm or more and 1000 nm or less.
The volume average particle diameter of the colorant refers to the particle diameter of the colorant itself, or the particle diameter to which the additive has adhered when an additive such as a dispersant is attached to the colorant. The volume average particle size is measured with a Microtrac UPA particle size analyzer UPA-UT151 (manufactured by Microtrac). The measurement was performed by putting the ink diluted 1000 times into a measurement cell. As input values at the time of measurement, the viscosity of the ink diluent was used as the viscosity, and the refractive index of the particle was used as the particle refractive index.

  The content (concentration) of the colorant is, for example, preferably 1% by mass to 25% by mass and more preferably 2% by mass to 20% by mass with respect to the ink.

The polymer particles will be described.
The polymer particles are a component that improves the fixability of an image with ink on a non-permeable recording medium.

  Examples of the polymer particles include styrene-acrylic acid copolymer, styrene-acrylic acid-sodium acrylate copolymer, styrene-butadiene copolymer, polystyrene, acrylonitrile-butadiene copolymer, and acrylate copolymer. And particles (latex particles) such as polyurethane, silicon-acrylic acid copolymer, and acrylic-modified fluororesin. Examples of the polymer particles include core / shell type polymer particles having different compositions at the center and outer edge of the particles.

  The polymer particles may be dispersed in the ink using an emulsifier, or may be dispersed in the ink without using an emulsifier. As an emulsifier, a polymer having a hydrophilic group such as a surfactant, a sulfonic acid group, or a carboxyl group (for example, a polymer having a hydrophilic group grafted thereto, a hydrophilic monomer and a hydrophobic portion) Polymers obtained from monomers).

The volume average particle size of the polymer particles is preferably 10 nm or more and 300 nm or less, more preferably 10 nm or more and 200 nm or less, from the viewpoint of glossiness and scratch resistance of the image.
The volume average particle size of the polymer particles is measured with a Microtrac UPA particle size analyzer UPA-UT151 (manufactured by Microtrac). The measurement was performed by putting the ink diluted 1000 times into a measurement cell. As input values at the time of measurement, the viscosity of the ink diluent was used as the viscosity, and the refractive index of the particles was used as the refractive index of the polymer.

The glass transition temperature of the polymer particles is preferably −20 ° C. or more and 80 ° C. or less, more preferably −10 ° C. or more and 60 ° C. or less, from the viewpoint of image scratch resistance.
The glass transition temperature of the polymer particles is determined from the DSC curve obtained by differential scanning calorimetry (DSC). More specifically, the method for determining the glass transition temperature in JIS K7121-1987 “Method for Measuring Plastic Transition Temperature”. It is calculated | required by description "extrapolated glass transition start temperature" of description.

  The content of the polymer particles is, for example, preferably from 0.1% by mass to 10% by mass, and more preferably from 0.5% by mass to 5% by mass with respect to the ink.

Explain about water.
As water, ion-exchanged water, ultrapure water, distilled water, and ultrafiltered water are particularly preferable from the viewpoint of preventing contamination of impurities or generation of microorganisms.

  The water content is, for example, preferably 10% by mass to 95% by mass and more preferably 30% by mass to 90% by mass with respect to the ink.

The water-soluble organic solvent will be described.
Examples of the water-soluble organic solvent include polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, and sulfur-containing solvents. Other examples of the water-soluble organic solvent include propylene carbonate and ethylene carbonate.

  Polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2-hexanediol, 1,2,6-hexanetriol, glycerin, trimethylol Sugar alcohols such as propane and xylitol; sugars such as xylose, glucose and galactose;

  Polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diglycerin. And ethylene oxide adducts.

Examples of the nitrogen-containing solvent include pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, triethanolamine and the like.
Examples of alcohols include ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol.
Examples of the sulfur-containing solvent include thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like.

  The water-soluble organic solvent may be used alone or in combination of two or more.

  1 mass% or more and 60 mass% or less are preferable with respect to water, and, as for content of a water-soluble organic solvent, 1 mass% or more and 40 mass% or less are more preferable.

The surfactant will be described.
The ink may contain other surfactant. Examples of other surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Preferably, anionic surfactants and nonionic surfactants are used. is there.

Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfuric acid of higher alcohol ether. Examples thereof include ester salts and sulfonates, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, and the like.
Among these, as anionic surfactants, dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, monobutylbiphenylsulfonate, dibutylphenylphenol A disulfonate is preferable.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, poly Examples thereof include oxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkyl alkanol amide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol and the like.
Among these, nonionic surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene Oxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, polyethylene glycol polypropylene glycol block copolymer, and acetylene glycol are preferred.

  Other nonionic surfactants include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; And biosurfactants such as spicrispolic acid, rhamnolipid, and lysolecithin.

  The hydrophilic / hydrophobic balance (HLB) of the surfactant is preferably in the range of 3 to 20, for example, in consideration of solubility.

  The surfactant may be used alone or in combination of two or more.

  The content of the surfactant is preferably from 0.1% by weight to 10% by weight, more preferably from 0.1% by weight to 5% by weight, and more preferably from 0.2% by weight to 3% by weight with respect to the ink. Further preferred.

Other additives will be described.
The ink may contain other additives. Other additives include ink ejection improvers (polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethylene glycol, ethylcellulose, carboxymethylcellulose, etc.), conductivity / pH adjusters (potassium hydroxide, sodium hydroxide, lithium hydroxide, etc.) Alkali metal compounds), reactive diluents, penetrants, pH buffers, antioxidants, fungicides, viscosity modifiers, conductive agents, chelating agents, UV absorbers, infrared absorbers, etc. Can be mentioned.

The preferred physical properties of the ink will be described.
The pH of the ink is preferably in the range of 4 to 10 and more preferably in the range of 5 to 9.
Here, the pH of the ink is 23 ± 0.5 ° C. and 55 ± 5% humidity. H. Under the environment, a value measured by a pH / conductivity meter (MPC227 manufactured by METTLER TOLEDO) is adopted.

The conductivity of the ink is, for example, in the range of 0.01 S / m to 0.5 S / m (preferably in the range of 0.01 S / m to 0.25 S / m, more preferably in the range of 0.01 S / m to 0.000. 20 S / m or less).
The conductivity is measured by MPC227 (pH / Conductivity Meter, manufactured by METTLER TOLEDO).

Examples of the viscosity of the ink include a range of 1.5 mPa · s to 30 mPa · s (preferably a range of 1.5 mPa · s to 20 mPa · s).
The viscosity is measured under the conditions of TV-20 (manufactured by Toki Sangyo) as a measuring device, a measurement temperature of 23 ° C., and a shear rate of 1400 s ⁻¹ .

(Recording device / recording method)
The recording apparatus according to the present embodiment is a recording apparatus including an ejection head that ejects each water-based ink of the ink set according to the present embodiment onto a non-permeable recording medium. According to the recording apparatus according to the present embodiment, a recording method having an ejection step of ejecting each water-based ink of an ink set onto an impermeable recording medium is realized.

  The recording apparatus according to the present embodiment may further include a drying apparatus that dries each water-based ink ejected on a non-permeable recording medium. In the recording apparatus further provided with the drying device, a recording method further including a drying step of drying each water-based ink ejected on the non-permeable recording medium is realized. High speed recording is realized by drying each water-based ink ejected on a non-permeable recording medium by a drying device (drying step).

  The recording apparatus according to the present embodiment may include an ink cartridge set that accommodates each water-based ink of the ink set according to the present embodiment and is made into a cartridge so as to be attached to and detached from the recording apparatus.

  Hereinafter, an example of a recording apparatus and a recording method according to the present embodiment will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram illustrating a recording apparatus according to the present embodiment.
As shown in FIG. 1, the recording apparatus 10 according to the present embodiment discharges a water-based ink (hereinafter also referred to as “ink”) onto a non-permeable recording medium P (an ejection apparatus having the ejection head 122). 121). In the recording apparatus 10 according to the present embodiment, a recording method including an ejection process for ejecting ink onto the non-permeable recording medium P is realized. As a result, an ink image is recorded on the impermeable recording medium P.

  Specifically, the recording apparatus 10 according to the present embodiment includes, for example, an image recording unit 12 that records an image on a continuous paper (hereinafter also referred to as “continuous paper P”) as an impermeable recording medium P. It has.

  The recording apparatus 10 adjusts the pre-processing unit 14 in which the continuous paper P supplied to the image recording unit 12 is accommodated, the conveyance amount of the continuous paper P supplied from the pre-processing unit 14 to the image recording unit 12, and the like. And a buffer unit 16. The buffer unit 16 is disposed between the image recording unit 12 and the preprocessing unit 14.

  The recording apparatus 10 includes, for example, a post-processing unit 18 that stores the continuous paper P discharged from the image recording unit 12, and a conveyance amount of the continuous paper P discharged from the image recording unit 12 to the post-processing unit 18. A buffer unit 20 to be adjusted. The buffer unit 20 is disposed between the image recording unit 12 and the post-processing unit 18.

  The recording apparatus 10 includes a cooling unit 22 that is disposed between the image recording unit 12 and the buffer unit 20 and cools the continuous paper P that is carried out of the image recording unit 12.

  The image recording unit 12 includes, for example, a roll member (not shown) that guides the continuous paper P along the conveyance path 124 of the continuous paper P, and a continuous paper that is conveyed along the conveyance path 124 of the continuous paper P. And an ejection device 121 that ejects ink (ink droplets) onto the paper P to record an image.

The ejection device 121 includes an ejection head 122 that ejects ink onto the continuous paper P. The ejection head 122 has, for example, an effective recording area (arrangement area of nozzles for ejecting ink) equal to or greater than the width of the continuous paper P (the length in a direction intersecting (for example, orthogonal to) the continuous paper P conveyance direction). This is a long recording head.
The ejection head 122 is not limited to this, and is an ejection head that is shorter than the width of the continuous paper P, and is a system that discharges ink by moving in the width direction of the continuous paper P (so-called carriage system). The discharge head may be used.

  The ejection head 122 may be a so-called thermal system that ejects ink droplets by heat, or may be a so-called piezoelectric system that ejects ink droplets by pressure, and a known one is applied. The

  The ejection head 122 includes, for example, an ejection head 122K that ejects ink onto the continuous paper P and records a K (black) color image, an ejection head 122Y that records a Y (yellow) color image, and an M (magenta). ) A discharge head 122M that records a color image, and a discharge head 122C that records a C (cyan) color image. The ejection head 122K, the ejection head 122Y, the ejection head 122M, and the ejection head 122C follow the conveyance direction of the continuous paper P in this order (hereinafter sometimes simply referred to as “paper conveyance direction”). Thus, the paper sheets are arranged so as to face the continuous paper P from the upstream side to the downstream side. In the description of the ejection head, when K, Y, M, and C are not distinguished, the symbols K, Y, M, and C are omitted.

  The ejection heads 122K, 122Y, 122M, and 122C are connected to ink cartridges 123K, 123Y, 123M, and 123C of each color that are attached to and detached from the recording apparatus 10 through supply pipes (not shown). Are supplied to the ejection head 122, respectively.

  The ejection head 122 is not limited to the form in which the four ejection heads 122 corresponding to each of the above four colors are arranged, and according to the purpose, four or more ejections corresponding to each of four or more colors including other intermediate colors. The form which has arrange | positioned the head 122 may be sufficient.

  Here, as the ejection head 122, for example, a low-resolution ejection head 122 (e.g., a 600 dpi ejection head) that ejects ink in an ink droplet amount range of 1 to 15 pl, and an ink droplet amount in a range of less than 10 pl. Any one of the high-resolution ejection heads 122 (for example, 1200 dpi ejection head) for ejection may be provided. Further, the discharge device 121 may include both a low-resolution discharge head 122 and a high-resolution discharge head 122. The ink droplet amount of the ejection head 122 is in the range of the maximum ink droplet amount. Also, dpi means “dot per inch”

  In the discharge device 121, for example, the back surface of the continuous paper P is wound on the downstream side in the paper conveyance direction with respect to the discharge head 122, and the continuous paper is rotated while being driven in contact with the continuous paper P to be conveyed. A drying drum 126 (an example of a drying device) for drying an image (ink) on P is disposed.

  A heating source (for example, a halogen heater or the like: not shown) is built in the drying drum 126. The drying drum 126 dries the image (ink) on the continuous paper P by heating with a heating source.

  Around the drying drum 126, a hot air blower 128 (an example of a drying device) that dries an image (ink) on the continuous paper P is disposed. The image (ink) on the continuous paper P wound around the drying drum 126 is dried by the warm air from the warm air blower 128.

  Here, the ejection device 121 has a near-infrared heater (not shown) for drying an image (ink) on the continuous paper P, a laser irradiation device, and the like downstream of the ejection head 122 in the paper conveyance direction. The drying device may be arranged. Other drying devices such as a near-infrared heater and a laser irradiation device are arranged instead of at least one of the drying drum 126 and the hot air blowing device 128 or in addition to the drying drum 126 and the hot air blowing device 128.

  On the other hand, the preprocessing unit 14 includes a supply roll 14A around which the continuous paper P supplied to the image recording unit 12 is wound. The supply roll 14A is rotatably supported by a frame member (not shown). ing.

  In the buffer unit 16, for example, a first pass roller 16A, a dancer roller 16B, and a second pass roller 16C are arranged along the paper transport direction. The dancer roller 16 </ b> B moves up and down in FIG. 1 to adjust the tension of the continuous paper P conveyed to the image recording unit 12 and the conveyance amount of the continuous paper P.

  The post-processing unit 18 includes a winding roll 18A as an example of a transport unit that winds the continuous paper P on which images are recorded. The take-up roll 18 </ b> A receives a rotational force from a motor (not shown) and rotates so that the continuous paper P is transported along the transport path 124.

  In the buffer unit 20, for example, a first pass roller 20A, a dancer roller 20B, and a second pass roller 20C are arranged along the paper transport direction. The dancer roller 16 </ b> B moves up and down in FIG. 1 to adjust the tension of the continuous paper P discharged to the post-processing unit 18 and the conveyance amount of the continuous paper P.

  The cooling unit 22 is provided with a plurality of cooling rollers 22A. The continuous paper P is cooled by conveying the continuous paper P between the plurality of cooling rollers 22A.

Next, an operation (recording method) by the recording apparatus 10 according to the present embodiment will be described.
In the recording apparatus 10 according to the present embodiment, first, the continuous paper P is conveyed from the supply roll 14 </ b> A of the preprocessing unit 14 to the image recording unit 12 through the buffer unit 16.
Next, in the image recording unit 12, ink is ejected from the ejection heads 122 of the ejection device 121 onto the continuous paper P. As a result, an ink image is formed on the continuous paper P. Thereafter, the image (ink) on the continuous paper P is dried from the back side of the continuous paper P (the surface opposite to the recording surface) by the drying drum 126. Then, the ink (image) discharged onto the continuous paper P is dried from the surface side (recording surface) of the continuous paper P by the hot air blower 128. That is, the ink discharged onto the continuous paper P is dried by the drying drum 126 and the hot air blowing device 128.
Next, in the cooling unit 22, the continuous paper P on which the images are recorded is cooled by the cooling roller 22A.
Next, through the buffer unit 16, the post-processing unit 18 winds the continuous paper P on which the images are recorded by the winding roll 18A.

  Through the steps described above, an ink image is recorded on the continuous paper P as the non-permeable recording medium P.

  In the recording apparatus 10 according to the present embodiment, the method of directly ejecting ink droplets onto the surface of the recording medium P by the ejection device 121 (ejection head 122) has been described. Alternatively, after the ink droplets are discharged, the ink droplets on the intermediate transfer member may be transferred to the recording medium P.

  Further, in the recording apparatus 10 according to the present embodiment, the method of recording an image by ejecting ink onto the continuous paper P as the recording medium P has been described. However, the image by ejecting ink onto the sheet as the recording medium P is described. May be used.

  Further, it is needless to say that this embodiment is not limitedly interpreted and is realized within a range that satisfies the requirements of the present invention.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

<Example 1>
(Cyan ink; written as “C ink”)
・ C. I. Pigment Blue 15: 3 (colorant): 5% by mass
・ Styrene / acrylic acid copolymer sodium neutralized product: 2.5% by mass
(Water-soluble resin, weight average molecular weight = 30000)
TOCRYL W-4627 (acrylic emulsion; manufactured by Toyochem): 2.5% by mass (solid content)
(Polymer particles, volume average particle size = 0.12 μm, glass transition temperature = 45 ° C.)
・ Glycerin: 10% by mass
Surfactant (compound described in Table 1): mass% described in Table 1
-Ion-exchange water: remainder After mixing the said composition, it filtered with a 5 micrometer filter, and obtained the water-based ink (C ink).

(Magenta ink; written as “M ink”)
As a colorant, C.I. I. M ink was obtained in the same manner as C ink except that Pigment Red 122 was used.

(Indicated as yellow ink; Y ink)
As a colorant, C.I. I. A Y ink was obtained in the same manner as the C ink except that Pigment Yellow 128 was used.

(Black ink; K ink)
A K ink was obtained in the same manner as the C ink, except that carbon black (Moul L: manufactured by Cabot Corporation) was used as the colorant.

(Ink set)
The obtained C ink, M ink, Y ink, and K ink were used as the ink set of Example 1.

<Examples 2-7, Comparative Examples 1-5>
Ink sets were prepared in the same manner as in Example 1 except that the type and amount (mass%) of the surfactant were changed according to Tables 1 and 2.

<Evaluation>
(Preparation of recording device)
A recording apparatus having the same configuration as that shown in FIG. 1 and having a 600 dpi piezo head (maximum ink droplet amount 11 pl) as an ink ejection head was prepared. The details of the prepared recording apparatus are as follows.
-Details of the recording device-
Recording speed (recording medium transport speed): 25 m / min
・ Dry drum set temperature: 100 ℃
・ Set temperature of hot air blower: 100 ° C
・ Non-permeable recording medium: “OK Top Coat +” (43 kg)

  Then, each color ink of each ink set of each example was filled in each color ink tank of the recording apparatus. The following image recording was performed using this recording apparatus.

(Image recording)
Using each recording apparatus, ink was ejected from a 600 dpi piezo head (maximum ink droplet amount 11 pl) onto Oji Paper's “OK Top Coat +” as a non-permeable recording medium, 1.5 cm × 1. A solid image of 5 cm (a solid image of a tertiary color using C ink, M ink, and Y ink, and a solid image of a quaternary color using four colors of ink) was recorded. Then, it dried with the drying drum and the warm air blower, and cooled with the cooling roller. Through this process, an ink image was recorded on a non-permeable recording medium.
Then, the recorded image was visually observed to evaluate image peeling due to poor drying. The evaluation criteria are as follows.

-Image peeling evaluation criteria-
A + (◎): No peeling at the quaternary color portion of the image A (◯): No peeling at the tertiary color portion of the image B (Δ): Some peeling of the image C (×): Image Exfoliation is extremely dirty

The details of each example and the evaluation results are listed in Tables 1 to 4 below.
Note that in the column of the difference in dynamic surface tension change width, the values shown in the upper row are the differences in the dynamic surface tension change width between the four inks of C ink, M ink, Y ink, and K ink. The maximum value is shown. On the other hand, the numerical value in the parenthesis at the lower stage indicates the maximum value of the change width difference of the dynamic surface tension between the three colors of the C ink, the M ink, and the Y ink.

  From the above results, it can be seen that in the ink set of this example, image peeling due to the inks of a plurality of colors is suppressed with respect to the non-permeable recording medium as compared with the ink set of the comparative example.

Details of abbreviations and the like in Tables 1 and 2 are as follows.
-Ethylene oxide adduct of acetylene glycol (Nisshin Chemical Industry)-
・ Orphine E1010 (HLB = 13-14)
・ Olfin EXP. 4001 (HLB = 8-11)
・ Olfin EXP. 4123 (HLB = 11-14)
・ Olfin EXP. 4300 (HLB = 10-13)

-Polyether-modified silicone (Nissin Chemical Industry Co., Ltd.)-
・ Silface SAG002 (HLB = 12)
・ Silface SAG503A (HLB = 11)

DESCRIPTION OF SYMBOLS 10 Recording device 12 Image recording unit 12 Discharge device 14 Pre-processing unit 14A Supply roll 16 Buffer unit 16A First pass roller 16B Dancer roller 16C Second pass roller 18 Post-processing unit 18A Take-up roll 20 Buffer unit 20A First pass roller 20B Dancer roller 20C Second pass roller 22 Cooling unit 22A Cooling roller 121 Discharge device 122, 122K, 122Y, 122M, 122C Discharge head 123, 123K, 123Y, 123M, 123C Ink cartridge 124 Conveyance path 126 Drying drum 128 Hot air blower P Recording medium

Claims (7)

Contains a colorant, polymer particles, water, and an aqueous organic solvent, has a static surface tension of 28 mN / m or less, and dynamic surface tension measured by the maximum bubble pressure method is dynamic from 1 msec to 1 sec. The variation range of the surface tension is 0.2 mN / m or more and 2.0 mN / m or less, and there are a plurality of water-based inks having different colors.
An ink set in which a difference in the fluctuation range of the dynamic surface tension between the water-based inks of the plurality of colors is 0 mN / m or more and 1.0 mN / m or less.   2. The dynamic surface tension after 1 msec in the multi-color water-based ink is 32 mN / m or less, and the dynamic surface tension after 1 sec in the multi-color water-based ink is 30 mN / m or less. The ink set described in 1.   An ink cartridge set containing each water-based ink of the ink set according to claim 1.   A recording apparatus comprising: an ejection head that ejects each aqueous ink of the ink set according to claim 1 or 2 onto a non-permeable recording medium.   The recording apparatus according to claim 4, further comprising a drying device that dries each of the water-based inks ejected on the non-permeable recording medium.   A recording method comprising a discharge step of discharging each water-based ink of the ink set according to claim 1 or 2 onto a non-permeable recording medium.   The recording method according to claim 6, further comprising a drying step of drying each water-based ink ejected on the non-permeable recording medium.