JP6492487B2 - Image recording device - Google Patents

Description

  The present invention relates to an ink set and an image recording apparatus.

Inkjet printing technology has been greatly increasing in recent years in the printing field because it is easy to increase the width and speed.
There is an increasing demand for recording with a water-based inkjet ink on a medium (slowly permeable medium, non-penetrable medium) in which liquid permeation is slow, such as coated paper for printing.

Moreover, as a conventional ink composition, what is described in patent document 1, for example is known.
Patent Document 1 includes at least a recording liquid containing at least a colorant and a polymerizable compound and a treatment liquid containing at least one polysiloxane compound and substantially not containing a colorant. A characteristic ink set for inkjet recording is described.

JP 2007-313839 A

  An object of the present invention is to provide an ink set capable of obtaining an image excellent in abrasion resistance when an image is formed on a recording medium by an ink jet recording apparatus as compared with a case where a treatment liquid containing an aggregating agent is not used. is there.

The above-described problems of the present invention have been solved by the means described in <1> or <4> below. The preferred embodiments are shown below together with <2>, <3>, <5>, and <6>.
<1> An inkjet recording ink and a treatment liquid, wherein the inkjet recording ink contains at least a colorant, polymer particles, a surfactant, and water, and has a dynamic surface tension by a maximum bubble pressure method. When measured, the dynamic surface tension after 1 msec is 32 mN / m or less, and the change range of the dynamic surface tension from 1 msec to 1 sec is 0.2 mN / m to 3.0 mN / m, An ink set, wherein the treatment liquid contains water and a flocculant;
<2> The ink set according to <1>, wherein the flocculant is selected from the group consisting of an organic acid, a polyvalent metal salt, and a cationic polymer.
<3> The ink set includes a magenta inkjet recording ink, a cyan inkjet recording ink, a yellow inkjet recording ink, and a black inkjet recording ink as the inkjet recording ink. <1> or <2>, the ink set according to
<4> The method according to any one of <1> to <3>, including a processing liquid applying unit that applies a processing liquid onto the recording medium, and a discharge unit that discharges ink for inkjet recording onto the recording medium. An image recording apparatus using an ink set,
<5> The image recording apparatus according to <4>, further comprising a drying means for heating and drying the treatment liquid and / or ink for ink jet recording.
<6> The recording medium according to <4> or <5>, wherein the ink-jet recording ink has a maximum liquid absorption of 15 mL / m ² or less at a contact time of 500 msec as measured by a dynamic operation absorption meter. Image recording device.

According to the inventions described in the above <1> to <3>, in the case where an image is formed on a recording medium by an ink jet recording apparatus, the image is excellent in abrasion resistance as compared with the case where no treatment liquid containing a flocculant is used. Can be provided.
According to the inventions described in <4> and <5> above, when an image is formed on a recording medium by an ink jet recording apparatus, as compared with a case where an ink set containing a treatment liquid containing an aggregating agent is not used. An image recording apparatus capable of obtaining an image having excellent abrasion resistance can be provided.
According to the invention described in <6> above, the inkjet recording apparatus uses the inkjet recording apparatus on the recording medium in which the maximum liquid absorption amount of the inkjet recording ink at a contact time of 500 msec measured by a dynamic operation absorption meter is 15 mL / m ² or less. When forming an image, it is possible to provide an image recording apparatus capable of obtaining an image excellent in abrasion resistance as compared with a case where an ink set containing a treatment liquid containing a flocculant is not used.

It is a schematic block diagram which shows an example of the inkjet recording device of this embodiment.

  Hereinafter, this embodiment will be described in detail. In addition, in this embodiment, description with "A-B" showing a numerical range represents the range including not only the range between A and B but A and B which are the both ends.

(Ink set)
The ink set of the present embodiment includes an ink for ink jet recording (hereinafter also simply referred to as “ink” or “ink of the present embodiment”) and a treatment liquid. When the dynamic surface tension is measured by the maximum bubble pressure method and contains at least molecular particles, a surfactant, and water, the dynamic surface tension after 1 msec is 32 mN / m or less, and 1 sec after 1 msec. The change width of the dynamic surface tension until later is 0.2 mN / m or more and 3.0 mN / m or less, and the treatment liquid contains water and a flocculant.

When recording with a water-based inkjet ink on a recording medium (slowly permeable medium, non-penetrable medium) such as a coated paper for printing, the conventional water-based ink has a poor ink absorbability. The image fixability (rubbing resistance) on paper was poor.
The present inventors have intensively studied, and by using a water-based ink containing polymer particles and having specific dynamic surface tension characteristics, wetting and spreading are good even on a slow-penetrating recording medium. I found it possible. Furthermore, it has been found that the rub resistance (image fixability) is further improved by using it together with a treatment liquid containing a flocculant. In particular, the present inventors have found that after image recording (printing), occurrence of image disturbance in post-printing processes such as cutting and bookbinding is suppressed.
Although the detailed mechanism is unknown, it is presumed that the above-mentioned specific ink is easy to spread and wet, and that it is excellent in abrasion resistance when used in combination with a treatment liquid containing a flocculant.
Hereinafter, the ink for ink jet recording and the treatment liquid constituting the ink set of the present embodiment will be described.

<Ink for inkjet recording>
The ink for ink jet recording (ink) used in the present embodiment contains at least a colorant, polymer particles, a surfactant, and water, and after measuring the dynamic surface tension by the maximum bubble pressure method, after 1 msec. Dynamic surface tension at 32 mN / m or less, dynamic surface tension after 1 sec is less than 32 mN / m, and the range of change in dynamic surface tension from 1 msec to 1 sec after is 0.2 mN / m It is above 3.0mN / m.
The ink is an aqueous ink containing water. In addition to water, a water-soluble organic solvent may be contained.

Ink having dynamic surface tension after 1 msec (milliseconds) and after 1 sec (seconds) of the above range, and dynamic surface tension fluctuation range, the dynamic surface tension is reduced after reducing each dynamic surface tension. This ink has a small fluctuation range of tension. In other words, this ink indicates an ink having the property of easily spreading on the recording medium.
The ink having the property of easily spreading on the recording medium and containing the polymer particles spreads quickly on the recording medium when discharged onto the permeable recording medium, and records the liquid component in the ink. It is presumed that penetration into the medium is promoted. At this time, the polymer particles, which are solid components in the ink, are delayed in penetrating into the recording medium (that is, between the paper fibers), and the dispersion stability is weakened due to the interaction with the flocculant in the treatment liquid described later. It is presumed that the interaction (interaction) between polymer particles becomes strong.
When the interaction between the polymer particles becomes stronger, the apparent viscosity in the vicinity of the polymer particles increases, and the polymer particles tend to remain on the surface of the recording medium, and the surface direction of the recording medium (along the surface). The colorant, which is also a solid component of the ink, is taken into the interaction between the polymer particles and easily remains on the surface of the recording medium, and the surface direction of the recording medium (the direction along the surface) ) Is estimated to be difficult to spread. In particular, since the ink has the surface tension characteristics, when a part of the liquid component in the ink is absorbed into the recording medium, the ink stability is easily lost due to the action of the treatment liquid, and the liquid component in the ink It is presumed that separation from the solid content (colorant and polymer particles) is promoted, and these phenomena are likely to occur.
Furthermore, it is estimated that it is excellent also in abrasion resistance compared with the conventional water-based ink.

The dynamic surface tension after 1 msec in the ink used in the present embodiment is 32 mN / m or less, and is preferably 25 to 31 mN / m from the viewpoint of further suppressing image bleeding and image peeling. 27 to 31 mN / m is more preferable.
The range of change in dynamic surface tension from 1 msec to 1 sec after the ink used in the present embodiment is 0.2 mN / m or more and 3.0 mN / m or less, further suppressing image bleeding and abrasion resistance. From the point of improving, it is preferable that it is 0.9-3.0 mN / m, and it is more preferable that it is 1.0-3.0 mN / m. In addition, since the change width of the dynamic surface tension from 1 msec to 1 sec later becomes smaller as time elapses, the dynamic surface tension after 1 sec from the value of the dynamic surface tension after 1 msec. Equal to the value obtained by subtracting the value of.

The dynamic surface tension in the present embodiment is a value measured by a maximum bubble pressure method in an environment of 23 ° C. and 55% RH using a 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, when the measurement limit of the maximum bubble pressure method dynamic surface tension meter is the dynamic surface tension after 1 msec, it 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.

The static surface tension of the ink used in the present embodiment is preferably less than 30 mN / m, more preferably 20 to 27 mN / m, from the viewpoint of ejection stability.
The static surface tension in the present embodiment is a value measured in an environment of 23 ° C. and 55% RH using a Wilhelmy type surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

In this embodiment, the ink for inkjet recording used for an ink set may be used individually by 1 type, and may use 2 or more types together. Among these, from the viewpoint of obtaining a full-color image, at least magenta inkjet recording ink, cyan inkjet recording ink, yellow inkjet recording ink, and black inkjet recording ink are used. It is preferable. In the case of using a plurality of colors of ink jet recording inks as described above, at least one ink is an ink jet ink constituting the ink set of the present embodiment, that is, a colorant, polymer particles, a surfactant, and When the dynamic surface tension is measured by the maximum bubble pressure method, the dynamic surface tension after 1 msec is 32 mN / m or less, and the dynamic surface tension from 1 msec to 1 sec is measured. It is preferable that the change width is an ink of 0.2 mN / m or more and 3.0 mN / m or less, and all the inks for ink jet recording contain at least a colorant, polymer particles, a surfactant, and water, And when dynamic surface tension was measured by the maximum bubble pressure method, the dynamic surface tension after 1 msec was 32 mN / m or less, and 1 se after 1 msec. It is more preferable range of change in dynamic surface tension until after it is less ink 0.2 mN / m or more 3.0 mN / m.
In the present embodiment, the ink jet recording ink is not limited to the above-described aspect, and may be configured in five colors including the white ink jet recording ink in addition to the above four colors. Further, a seven-color configuration in which light magenta ink and light cyan ink are further added may be used, and is not particularly limited.

[Surfactant]
In the ink, in order to make the dynamic surface tension after 1 msec or after 1 sec and the change range of the dynamic surface tension within the above range, the ink contains a surfactant. That is, it is preferable to adjust the dynamic surface tension after 1 msec or after 1 sec and the change range of the dynamic surface tension depending on the type and amount of the surfactant.

  As the surfactant used in the ink, for example, a surfactant having an HLB (hydrophilic group / hydrophobic group balance “Hydrophile-Lipophile Balance”) value of 14 or less is preferably exemplified. 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. In addition, the ink described above preferably contains two or more surfactants in view of easy preparation to the target dynamic surface tension and further suppresses image peeling. It is more preferable to contain 2 or 3 types, still more preferably 2 types.

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

  As the surfactant, an ethylene oxide adduct of acetylene glycol, an ethylene oxide adduct of acetylene alcohol, and a polyether-modified silicone are preferably mentioned, and an ethylene oxide adduct of acetylene glycol and a polyether-modified silicone are more preferred. More preferred are an ethylene oxide adduct of acetylene glycol and an ethylene oxide adduct of acetylene alcohol.

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 an integer of 1 to 30) Represents a compound.
Examples of commercially available products of ethylene oxide adducts of acetylene glycol (the numbers 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) (the above, Nissin Chemical Industry Co., Ltd. product) etc. are mentioned.

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.
Examples of commercially available polyether-modified silicones (the values in parentheses indicate HLB catalog values) are Silface SAG002 (12), Silface SAG503A (11), Silface SAG005 (7) Shin Chemical Industry Co., Ltd.).

  Among these, the ink contains, as a surfactant, two or more compounds selected from the group consisting of an acetylene glycol ethylene oxide adduct, an acetylene alcohol ethylene oxide adduct, and a polyether-modified silicone. It is more preferable to contain two or more acetylene glycol ethylene oxide adducts, and it is even more preferable to contain two acetylene glycol ethylene oxide adducts.

  Examples of other surfactants other than those described above include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants.

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 disulfonic acid salt etc. are mentioned preferably.

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 Preferable examples include oxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, polyethylene glycol polypropylene glycol block copolymer, and acetylene glycol.

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

  The surfactant content in the ink is preferably 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, and more preferably 0.5 to 8%, based on the total weight of the ink. It is more preferable that it is weight%, and it is especially preferable that it is 2-5 weight%. When it is in the above range, preparation to the intended dynamic surface tension is easy, and image peeling is further suppressed.

[Colorant]
The ink used in this embodiment contains a colorant.
As the colorant, a pigment is preferably exemplified.
Examples of the pigment include organic pigments and inorganic pigments, and there are no particular limitations, and known pigments are used.

  Specific examples of the black pigment (black pigment) include Raven7000, Raven5750, Raven5250, Raven5000 ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1200, Raven1190, Raven1190, Raven1190, ULTRAII, Raven1170. Manufactured), 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, M 1400 (above, manufactured by Cabot Corporation), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW200, Color Black S150, Color Black S150, Color Black S150, Color Black S150, Color Black S150, 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 140U, 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 (above, manufactured by Mitsubishi Chemical Corporation), and the like, but are not limited thereto.

Specific examples of cyan pigments include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 22, 60, and the like, but are not limited thereto.
Specific examples of the magenta 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 and the like, but are not limited thereto.
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, etc. However, it is not limited to these.

  Here, when a pigment is used as the colorant, the ink preferably contains a pigment dispersant. 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 Alkyl ester-methacrylic acid copolymer, styrene-acrylic acid alkyl ester-acrylic acid copolymer, styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer, and These salts It is. Moreover, you may copolymerize the monomer which has a polyoxyethylene group and a hydroxyl group with these polymers.
Among these, the ink used in this embodiment preferably contains a styrene-acrylic acid copolymer neutralized product, and the styrene-acrylic acid copolymer neutralized product is 0% relative to the total weight of the ink. It is preferable to contain 1 to 10% by weight, and more preferably 0.5 to 5% by weight of the neutralized styrene-acrylic acid copolymer based on the total weight of the ink.
As the styrene-acrylic acid copolymer neutralized product, an alkali metal salt of a styrene-acrylic acid copolymer is preferable, and a sodium salt of a styrene-acrylic acid copolymer is more preferable.

  The weight average molecular weight (Mw) of the polymer dispersant is preferably 2,000 or more and 50,000 or less, for example.

A pigment dispersant may be used individually by 1 type, or may use 2 or more types together.
Although the content of the pigment dispersant varies greatly depending on the pigment, it cannot be generally stated, but it is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the pigment.

Examples of the pigment include a pigment that self-disperses in water (hereinafter also referred to as “self-dispersing pigment”).
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 the self-dispersing pigment, in addition to the above-described pigment subjected to surface modification treatment, 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 Industries, Ltd. Commercially available self-dispersing pigments can also be mentioned.

  The self-dispersing pigment is preferably a pigment having at least a sulfonic acid, a sulfonate, a carboxylic acid, or a carboxylate as a functional group on the surface, and at least a carboxylic acid or a carboxylic acid as a functional group on the surface. A pigment having a salt is more preferable.

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 Corporation and Toyo Ink Corporation. 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 pigments, cyan, magenta, and yellow primary pigments, specific pigments such as red, green, blue, brown, and white, metallic luster pigments such as gold and silver, and colorless or light colored pigments. Examples include extender 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 preferably 10 nm or more and 1,000 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 placing 1,000-fold diluted ink in 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 preferably 1 to 25% by weight and more preferably 2 to 20% by weight with respect to the total weight of the ink.

[Polymer particles]
The ink used in the present embodiment contains polymer particles.
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 diameter 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 measurement of the volume average particle size of the polymer particles in the present embodiment is performed with a Microtrac UPA particle size analyzer UPA-UT151 (manufactured by Microtrac). The measurement is performed by placing 1,000-fold diluted ink in 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 higher and 80 ° C. or lower, and more preferably −10 ° C. or higher and 60 ° C. or lower 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 preferably from 0.1 to 10% by weight, more preferably from 0.5 to 5% by weight, based on the total weight of the ink.

〔water〕
The ink used in this embodiment contains 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 preferably 10 to 95% by weight, more preferably 30 to 90% by weight, based on the total weight of the ink.

(Water-soluble organic solvent)
The ink in the present embodiment preferably contains a water-soluble organic solvent.
Examples of the water-soluble organic solvent include polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, and sulfur-containing solvents. In addition, 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 Examples thereof include 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 contained singly or in combination of two or more.
The content of the water-soluble organic solvent is preferably 0.1 to 60% by weight, more preferably 1 to 50% by weight, and more preferably 5 to 40% by weight with respect to the total weight of the ink. Is more preferable, and it is especially preferable that it is 10 to 30 weight%.

[Other additives]
The ink used in this embodiment may contain other additives than those described above.
There is no restriction | limiting in particular as another additive, A well-known additive is used. Specifically, for example, an ink dischargeability improving agent (polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethylene glycol, ethylcellulose, carboxymethylcellulose, etc.), conductivity / pH adjuster (potassium hydroxide, sodium hydroxide, lithium hydroxide) Etc.), reactive diluents, penetrants, pH buffers, antioxidants, fungicides, viscosity modifiers, conducting agents, chelating agents, ultraviolet absorbers, infrared absorbers, etc. Is mentioned.
The pH of the ink used in this embodiment is preferably 4 to 10, and more preferably 5 to 9.
As the pH of the ink, a value measured with a pH / conductivity meter (MPC227 manufactured by METTLER TOLEDO) under a temperature of 23 ± 0.5 ° C. and a humidity of 55 ± 5% RH is adopted.
The conductivity of the ink used in the present embodiment is preferably 0.01 to 0.5 S / m, more preferably 0.01 to 0.25 S / m, and 0.01 to 0.20 S. More preferably, it is / m.
The conductivity is measured by MPC227 (pH / Conductivity Meter, manufactured by METTLER TOLEDO).
The viscosity of the ink used in the present embodiment is preferably 1.5 to 30 mPa · s, and more preferably 1.5 to 20 mPa · s.
Viscosity is measured using TV-20 (manufactured by Toki Sangyo Co., Ltd.) as a measuring device, at a measurement temperature of 23 ° C. and a shear rate of 1,400 s ⁻¹ .

<Processing liquid>
In the present embodiment, the treatment liquid contains water and a flocculant. The treatment liquid is preferably transparent or pale, more preferably transparent or white, and still more preferably transparent. The term “transparent” means that the treatment liquid does not contain a colorant or the content thereof is 1% by weight or less based on the total weight of the treatment liquid. That is, it does not exclude that the treatment liquid contains a small amount of colorant. When the treatment liquid is transparent, the content of the colorant in the treatment liquid is preferably 0 to 0.5% by weight, more preferably 0 to 0.1% by weight, and 0 to 0.01. It is more preferable that it is weight%, and it is especially preferable not to contain.
As the treatment liquid, one kind of treatment liquid may be used, or two or more kinds may be used in combination, but it is preferable to use only one kind, and it is more preferred to use a transparent treatment liquid.

[Flocculant]
In the present embodiment, the treatment liquid contains a flocculant. The flocculant contained in the treatment liquid is not particularly limited as long as it is a compound that lowers the dispersion stability of a substance dispersed in the ink and has an aggregating action. Specifically, it preferably has an action of reducing the dispersion stability of the polymer particles, the colorant and the like contained in the ink.
Examples of the flocculant include acidic compounds, polyvalent metal salts, and cationic polymers. Among these, an acidic compound is preferable from the viewpoint of the cohesiveness of the ink 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. Are preferable.

Among these, acidic compounds with high water solubility are preferable. Further, from the viewpoint of fixing the whole ink by reacting with the ink component, an acidic compound having a valence of 3 or less is preferable.
As the acidic compound, pyrrolidone carboxylic acid is particularly preferable.
An acidic compound may be used individually by 1 type, and may use 2 or more types together.

When the said processing liquid contains an acidic compound, it is preferable that the pH (25 degreeC) of a processing liquid is 0.1-6.8, It is more preferable that it is 0.5-6.0, 0.8 More preferably, it is -5.0.
Further, when the treatment liquid contains an acidic compound, a basic compound may be added in order to adjust the pH of the treatment liquid. Specifically, as the inorganic basic compound, an alkali metal hydroxide is used. (Lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.), alkali metal carbonates, alkaline earth metal carbonates, ammonium hydroxide, and the like. Examples of the organic basic compound include amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine; alcohol amines such as triethanolamine, diethanolamine and methyldiethanolamine, and tetraalkylammonium hydroxide.
Among these, as the basic compound, an alkali metal hydroxide is preferable from the viewpoint of availability.

The content of the acidic compound is preferably 40% by weight or less, more preferably 3 to 30% by weight, and still more preferably 5 to 20% by weight with respect to the total weight of the treatment liquid. . By setting the content of the acidic compound within the above range, the components in the ink can be more efficiently aggregated.
The application amount of the recording medium of the acidic compound is not particularly limited as long as the amount is large enough to aggregate the ink, from the viewpoint of aggregating the ink, is 0.5g / m ² ~4.0g / m ² it is more preferably ^{preferably, 0.9g / m 2 ~3.75g / m} 2.

-Multivalent metal salt-
The polyvalent metal salt is preferably a compound containing a divalent or higher metal such as an alkaline earth metal or a zinc group metal. For example, an acetate of a metal ion such as Ca ²⁺ , Cu ²⁺ , Al ³⁺ , An oxide etc. can be mentioned.
From the viewpoint of agglomeration reaction, the polyvalent metal salt preferably has a valence of 2 or more, and more preferably a polyvalent metal salt composed of a trivalent or more polyvalent metal ion.

The polyvalent metal salt is preferably at least one selected from the group consisting of the following polyvalent metal ion and anion salts, polyaluminum hydroxide and polyaluminum chloride.
Examples of the polyvalent metal ion include Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Sr ²⁺ , Zn ²⁺ , Ba ²⁺ , Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Co ³⁺ , Fe ²⁺ , La ³⁺ , Nd ³⁺ , Y ³⁺ , Zr ^{4+ and the} like can be mentioned. In order to contain these polyvalent metal ions in the treatment liquid, the polyvalent metal salt may be used.
The salt is a metal salt composed of the above polyvalent metal ions and an anion that binds to these ions, but is preferably soluble in a solvent. Here, the said solvent is a medium which comprises a process liquid with a polyvalent metal salt, for example, water and the organic solvent mentioned later are mentioned.
Preferred anions for forming a salt with the polyvalent metal ion include, for example, Cl ⁻ , NO ₃ ⁻ , I ⁻ , Br ⁻ , ClO ₃ ⁻ , CH ₃ COO ⁻ , SO ₄ ^{2− and the} like. .
A polyvalent metal ion and an anion can form a salt of a polyvalent metal ion and an anion, respectively, using a single species or a plurality of species.
Examples of other polyvalent metal salts include polyaluminum hydroxide and polyaluminum chloride.

Examples of the polyvalent metal salt, reactivity and coloring property, further in view of ease of handling, it is preferable to use a salt of a polyvalent metal ion and an anion, the polyvalent metal ion, Ca ^{2 At} least one selected from ⁺ , Mg ²⁺ , Sr ²⁺ , Al ³⁺ and Y ³⁺ is preferable, and Ca ²⁺ is more preferable.
As the anion, NO ₃ ⁻ is particularly preferable from the viewpoint of solubility and the like.
The said polyvalent metal salt can be used individually by 1 type or in mixture of 2 or more types.

When the treatment liquid contains the polyvalent metal salt, the content of the polyvalent metal salt is preferably 1% by weight or more with respect to the total weight of the treatment liquid. When the content of the polyvalent metal salt is 1% by weight or more, the components in the ink composition can be more effectively fixed.
The content of the polyvalent metal salt is preferably 1% by weight to 20% by weight, more preferably 2% by weight to 15% by weight, more preferably 3% by weight to 10% by weight with respect to the total weight of the treatment liquid. More preferably.
The application amount of the recording medium of the polyvalent metal salt is preferably, but not particularly limited insofar as the amount is sufficient for aggregating the ink composition is 0.5g / m ² ~4.0g / m ² , and more preferably ^{0.9g / m 2 ~3.75g / m 2} .

-Cationic polymer-
The cationic polymer includes at least one cationic selected from poly (vinyl pyridine) salt, polyalkylaminoethyl acrylate, polyalkylaminoethyl methacrylate, poly (vinyl imidazole), polyethyleneimine, polybiguanide, and polyguanide. Polymers.
A cationic polymer may be used individually by 1 type, and may use 2 or more types together.
Among the cationic polymers, polyguanides (preferably poly (hexamethyleneguanidine) acetate, polymonoguanide, polymeric biguanide), polyethyleneimine, and poly (vinylpyridine), which are advantageous from the viewpoint of aggregation rate, are preferable.

  The weight average molecular weight of the cationic polymer is preferably smaller in terms of the viscosity of the treatment liquid. When the treatment liquid is applied to the recording medium by an inkjet method, a range of 500 to 500,000 is preferable, a range of 700 to 200,000 is more preferable, and a range of 1,000 to 100,000 is more preferable. . When the weight average molecular weight is 500 or more, it is advantageous from the viewpoint of aggregation speed, and when it is 500,000 or less, it is advantageous from the viewpoint of ejection reliability. However, this is not the case when the treatment liquid is applied to the recording medium by a method other than inkjet.

  Commercially available products may be used as the cationic polymer, and examples thereof include Vinibrand 701FE35, Vinibrand 701FE50, and Vinibrand 701FE65 (manufactured by Nissin Chemical Industry Co., Ltd.).

  When the said processing liquid contains a cationic polymer, it is preferable that pH (25 degreeC) of a processing liquid is 1.0-10.0, It is more preferable that it is 2.0-9.0. More preferably, it is 0-7.0.

When the treatment liquid contains a cationic polymer, the content of the cationic polymer is preferably 1% by weight to 20% by weight of the polymer solid content with respect to the total weight of the treatment liquid, and 2.5% by weight. It is more preferable that it is% -15 weight%.
The amount of the cationic polymer applied to the coated paper is not particularly limited as long as it is an amount sufficient to agglomerate the ink, but from the viewpoint of aggregating the ink, 0.5 g / m ^{2 to} 4.0 g / m ^2. it is preferably, and more preferably ^{0.9g / m 2 ~3.75g / m 2} .

〔water〕
In the present embodiment, the treatment liquid contains 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 preferably 10 to 95% by weight, more preferably 30 to 90% by weight, based on the total weight of the treatment liquid.

(Water-soluble organic solvent)
The treatment liquid preferably contains at least one water-soluble organic solvent in addition to the flocculant and water. The details of the water-soluble organic solvent are the same as those in the ink, 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 embodiment. Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, antiseptics, fungicides, pH adjusters, surfactants, antifoaming agents. Known additives such as an agent, a viscosity modifier, a dispersant, a dispersion stabilizer, a rust inhibitor, and a chelating agent can be used.

(Image recording apparatus and image recording method)
The image recording apparatus according to the present embodiment preferably includes a processing liquid applying unit that applies a processing liquid onto the recording medium, and a discharge unit that discharges ink for inkjet recording onto the recording medium. The treatment liquid and the ink for ink jet recording are the treatment liquid and the ink for ink jet recording that constitute the ink set of the present embodiment.
The image recording method of the present embodiment preferably includes a treatment liquid application step for applying a treatment liquid onto the recording medium, and a discharge step for discharging ink for inkjet recording onto the recording medium. The treatment liquid and the ink for ink jet recording are the treatment liquid and the ink for ink jet recording that constitute the ink set of the present embodiment.
In the present embodiment, it is preferable to include the treatment liquid application step and the discharge step in this order. As a result, the treatment liquid and the ink are applied in this order on the recording medium, and the ink aggregates in a region close to the recording medium, so that the abrasion resistance is further improved.
In addition, when two or more types of ink are used in the discharge process described later, the treatment liquid application process may be performed only once before the discharge process, or the treatment liquid application process and the discharge process may be repeated. Although not particularly limited, an embodiment in which the treatment liquid application step is performed only once before the start of the discharge step is preferable from the viewpoint of obtaining the effect with fewer steps.
In the present embodiment, when using multicolor ink, as described above, an embodiment having an ejection step of ejecting multicolor ink onto a recording medium after the treatment liquid application step is preferable. After performing the discharge process using this ink, an embodiment in which the treatment liquid application process is performed and an aspect in which the treatment liquid application process is performed before or after the discharge process of each color ink can be performed without particular limitation.

<Processing liquid application means and processing liquid application process>
The image forming apparatus according to the present embodiment includes a processing liquid applying unit that applies a processing liquid onto a recording medium. Since the image recording apparatus of the present embodiment includes the treatment liquid application unit, it is possible to form an image having excellent abrasion resistance even on a recording medium that is slow to penetrate. Further, by having the treatment liquid applying means, it is possible to speed up image recording, and an image having excellent abrasion resistance can be obtained even at high speed recording. Even with high-speed recording, it is possible to obtain an image with high density and resolution and excellent drawing performance (for example, reproducibility of fine lines and fine portions).
In addition, the image recording method of the present embodiment includes a processing liquid application step of applying a processing liquid on the recording medium. Since the image recording method of the present embodiment includes the treatment liquid application step, an image having excellent abrasion resistance can be formed even on a recording medium with slow penetration. Further, by having the treatment liquid application step, it is possible to speed up image recording, and an image having excellent abrasion resistance can be obtained even at high speed recording. Even with high-speed recording, it is possible to obtain an image with high density and resolution and excellent drawing performance (for example, reproducibility of fine lines and fine portions).

As described above, the treatment liquid application process is preferably provided before the discharge process.
Since the treatment liquid application step is a step of applying a treatment liquid containing an aggregating agent capable of forming an agglomeration by contact with the ink, even if the treatment liquid application step is provided before the ink application step, It may be provided later. However, from the viewpoint of image quality and abrasion resistance, the treatment liquid application step is preferably provided before the discharge step. In other words, the discharge step is preferably a step that is provided after the treatment liquid application step and applies an ink material onto the treatment liquid of the recording medium to which the treatment liquid has been applied by the treatment liquid application step.

As the treatment liquid application means in the treatment liquid application means, a known liquid application means can be used without any particular limitation. For example, any means such as spray application, application by an application roller, application by an inkjet method, immersion, etc. can be used. You can choose.
Specifically, for example, a size press method represented by a horizontal size press method, a roll coater method, a calendar size press method, etc .; a knife coater method represented by an air knife coater method; a transfer roll such as a gate roll coater method Roll coater method represented by coater method, direct roll coater method, reverse roll coater method, squeeze roll coater method, etc .; bill blade coater method, short duel coater method; blade coater method represented by two stream coater method; rod Bar coater method represented by bar coater method, etc .; Bar coater method represented by rod bar coater method, etc .; Cast coater method; Gravure coater method; Curtain coater method; Die coater method; Brush coater method; Etc., and the like.
Moreover, the method of apply | coating by controlling a coating amount by using the coating device provided with the liquid quantity limiting member like the coating device of Unexamined-Japanese-Patent No. 10-230201 may be used.
Among these, from the viewpoint that it is preferable to apply the treatment liquid only to the region where ink is ejected, the application of the treatment liquid is preferably performed by an inkjet method. In addition, when using a cationic polymer as an aggregating agent, it is assumed that the viscosity of the treatment liquid is high and is not suitable for the ink jet method. In that case, the above-described bar coater method or the like may be appropriately employed. preferable.

The region to which the treatment liquid is applied may be the entire surface application that is applied to the entire recording medium or the partial application that is partially applied to the region where ink jet recording is performed in the ejection process.
Among these, it is preferable to apply the treatment liquid only to the region where ink is ejected in the ejection process from the viewpoint of suppressing the amount of the treatment liquid used and reducing the amount of the treatment liquid remaining on the recording medium.

The application amount of the treatment liquid to the recording medium is not particularly limited as long as the amount is large enough to aggregate the ink, from the viewpoint of aggregating the ink, is 0.5g / m ² ~4.0g / m ² it is more preferably ^{preferably, 0.9g / m 2 ~3.75g / m} 2.

[Drying means and drying step]
In the present embodiment, it is preferable that the image recording apparatus has a drying means for heating and drying the treatment liquid applied on the recording medium.
In the present embodiment, a discharge step is provided after the treatment liquid application step, and a drying step of heating and drying the treatment liquid on the recording medium after the treatment liquid is applied onto the recording medium and before ink is discharged. Is preferably provided. By preliminarily heating and drying the treatment liquid before the discharging step, bleeding is prevented and good image quality can be obtained.

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.
In the drying step, the surface temperature of the recording medium is preferably 35 ° C to 200 ° C, and more preferably 40 ° C to 150 ° C. Setting the temperature in the drying step within the above range is preferable because the ink can be dried quickly, while the scorching of the recording medium, the increase in apparatus cost, and the increase in power consumption are suppressed.
The surface temperature of the recording medium is a value measured as follows. First, a radiation thermometer is installed at a location 0.5 m from the drying device of the recording device by the recording medium conveyance distance. Then, with this radiation thermometer, the temperature of the non-image recording portion (white paper portion) of the recording medium is measured, and this measured temperature is obtained as the surface temperature of the recording medium.

<Discharge means and discharge process>
The image recording apparatus according to the present embodiment includes an ejection unit that ejects ink for inkjet recording onto a recording medium.
In addition, the image recording method of the present embodiment includes an ejection step for ejecting ink jet recording ink onto a recording medium. In the ejection step, it is preferable to eject ink droplets onto a recording medium by an inkjet head.
The ink jet head used for discharging ink droplets is not particularly limited, and a known ink jet head is used. Examples thereof include a piezo ink jet head and a thermal ink jet head.
The ink discharge temperature is not particularly limited and can be adjusted according to the ink used.
In the image recording apparatus and the image recording method of the present embodiment, ink ejection may be performed a plurality of times as necessary. For example, one type of ink may be ejected multiple times to the same location on the recording medium, two or more types of ink may be ejected once, or two or more types of ink may be ejected multiple times. May be.
The ink used in the present embodiment may be used alone or in combination of two or more. For example, when forming a color image, cyan, magenta, yellow, and black inks are preferably used.

In the image recording apparatus of the present embodiment and the image recording method of the present embodiment, the liquid weight per drop of ink droplet is preferably 25 ng or less, more preferably 0.5 ng to 20 ng, and more preferably 2 ng or more. More preferably, it is 15 ng or less. In the above embodiment, the drying property is excellent, and the occurrence of peeling in the image is further suppressed.
In the ink jet apparatus capable of ejecting a plurality of drops from one nozzle, the liquid weight per drop refers to the drop amount of the minimum drop that can be printed.

  The image recording apparatus of the present embodiment and the image recording method of the present embodiment preferably employ a thermal ink jet recording method or a piezo ink jet recording method from the viewpoint of an effect of improving bleeding and intercolor bleeding. Although the mechanism that brings about this effect has not been clarified, in the case of the thermal ink jet recording method, the ink is heated at the time of ejection and has a low viscosity, but the temperature of the ink on the recording medium decreases, so the viscosity is low. It grows rapidly. For this reason, it is considered that bleeding and intercolor bleeding have an improving effect. On the other hand, in the case of the piezo ink jet method, it is possible to discharge a high-viscosity liquid, and the high-viscosity liquid can suppress spreading in the paper surface direction on the recording medium. It is estimated that there is an improvement effect on intercolor bleeding.

In the image recording apparatus of the present embodiment and the image recording method of the present embodiment, the replenishment (supply) of ink to the ink jet head is preferably performed from an ink tank containing ink. The ink tank is preferably of a cartridge type that can be attached to and detached from the apparatus, and ink can be easily replenished by replacing the cartridge type ink tank.
The ink supply system preferably includes, for example, an original tank containing ink, a supply pipe, an ink tank immediately before the inkjet head, a filter, and a piezo-type inkjet head.

[Drying means and drying step]
The image forming apparatus of the present embodiment preferably further includes a drying unit that dries the ink ejected onto the recording medium. By having a drying means, high-speed image recording is realized.
In the present embodiment, the image recording method preferably further includes a drying step of drying the ink ejected on the recording medium. By having a drying step, high-speed image recording is realized.
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.
In the drying step, the surface temperature of the recording medium is preferably 35 ° C to 200 ° C, and more preferably 40 ° C to 150 ° C. Setting the temperature in the drying step within the above range is preferable because the ink can be dried quickly, while the scorching of the recording medium, the increase in apparatus cost, and the increase in power consumption are suppressed.
The surface temperature of the recording medium is a value measured as follows. First, a radiation thermometer is installed at a location 0.5 m from the drying device of the recording device by the recording medium conveyance distance. Then, with this radiation thermometer, the temperature of the non-image recording portion (white paper portion) of the recording medium is measured, and this measured temperature is obtained as the surface temperature of the recording medium.

  Further, in the image recording method of the present embodiment, an ink cartridge that contains the ink according to the present embodiment and is cartridge-mounted so as to be attached to and detached from the recording apparatus may be used. An ink cartridge set that contains 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 may be used.

〔recoding media〕
The recording medium used in the image recording apparatus of the present embodiment and the image recording method of the present embodiment is not particularly limited, and a known recording medium is used.
The ink set of the present embodiment is suitable for a non-penetrable recording medium in which it is difficult to obtain rub resistance because the blur of the image is suppressed even for a permeable recording medium that is liable to cause image bleeding. However, it has excellent abrasion resistance. For this reason, the ink set according to the present embodiment is excellent in versatility of the recording medium.
In addition, a plain paper etc. are mentioned as a permeable recording medium. Specifically, the permeable recording medium means a recording medium having a maximum ink absorption amount exceeding 15 ml / m ² within a contact time of 500 ms as measured by a dynamic scanning absorption meter.
On the other hand, examples of the impermeable recording medium include coated paper and resin film. 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 present embodiment, it is particularly preferable to use a non-permeable recording medium as the recording medium. In this embodiment, even when an impermeable recording medium is used as the recording medium, an image having excellent abrasion resistance can be obtained by using the ink and the treatment liquid in combination.

Hereinafter, an example of the image recording method of the present embodiment will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an example of an ink jet recording apparatus according to the present embodiment.
As shown in FIG. 1, the inkjet recording apparatus 10 is a recording apparatus that includes an ejection head 122 (an ejection apparatus 121 having the ejection head 122) that ejects aqueous ink (hereinafter also referred to as “ink”) onto a recording medium P. . In the ink jet recording apparatus 10, an image recording method (ink jet recording method) having an ejection process for ejecting ink onto the recording medium P is realized. Thereby, an image by ink is recorded on the recording medium P.

Specifically, the inkjet recording apparatus 10 includes an image recording unit 12 that records an image on a continuous paper (hereinafter, also referred to as “continuous paper P”) as a recording medium P, for example.
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 ejection head 122 may be a so-called thermal system that ejects ink droplets by heat, or may be a so-called piezo system that ejects ink droplets by pressure. Applied.
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 are in this order in the transport direction of the continuous paper P (hereinafter, simply referred to as “paper transport direction”). 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 ink jet recording apparatus 10 through supply pipes (not shown). Ink is supplied to each ejection head 122.
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 discharge head 122, for example, a low-resolution discharge head 122 (for example, a 600 dpi discharge head) that discharges ink in a range of ink droplet amount to 15 pl or less, ink is discharged in a range of ink droplet amount of less than 10 pl. Any of the high-resolution ejection heads 122 (for example, a 1,200 dpi ejection head) may be provided. Further, the ejection device 121 may include both a low resolution ejection head 122 and a high resolution ejection head 122. The ink droplet amount of the ejection head 122 is in the range of the maximum ink droplet amount. In addition, 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 recording medium P.
In the inkjet recording apparatus 10, 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. However, the present invention is not limited to this. A method of transferring ink droplets on the intermediate transfer member to the recording medium P after discharging the droplets may be used.

  Further, in the inkjet recording apparatus 10, the method of recording an image by ejecting ink onto the continuous paper P as the recording medium P has been described. However, the method of recording the image by ejecting ink onto a sheet as the recording medium P It may be.

  Hereinafter, the present embodiment will be described in detail with reference to examples. However, the present embodiment is not limited only to the following examples. In the following description, “parts” means “parts by weight” unless otherwise specified.

(Measuring method)
<Measurement method of dynamic surface tension of ink>
The dynamic surface tension was measured using a maximum bubble pressure method dynamic surface tension meter MPTC (manufactured by LAUDA) in an environment of 23 ° C. and 55% RH.
The value of the dynamic surface tension after 1 msec was the value of the dynamic surface tension when the maximum bubble pressure was reached in 1 msec after a new interface was 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 1 msec, it may be expressed as the dynamic surface tension after 0 msec. In this case, the value of dynamic surface tension after 0 msec was adopted as the value of dynamic surface tension after 1 msec.
On the other hand, the value of the dynamic surface tension after 1 sec was the value of the dynamic surface tension when the maximum bubble pressure was reached in 1 sec after a new interface was 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. .

<Measurement method of static surface tension of ink>
The static surface tension of the ink was measured in a 23 ° C. and 55% RH environment using a Wilhelmy type surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

(Preparation of inkjet inks 1 to 5)
The components listed in Table 1 were mixed to prepare inkjet inks 1-5.
The measured values of static surface tension and dynamic surface tension are summarized in Table 1.
In Table 1, the numerical value of each component means weight% as a solid content, and the amount of ion-exchanged water is added as the balance so that each component becomes the weight%.
After mixing the components described in Table 1, inkjet inks 1 to 5 were prepared by filtering with a filter having a pore size of 5 μm (manufactured by ADVANTEC, A500A090C).

The components used in Table 1 above are as follows.
Carbon black: Mogul L, manufactured by Cabot Co., Ltd. Styrene-acrylate ester-acrylate copolymer: (water-soluble resin, average molecular weight 30,000), styrene: ethyl acrylate: acrylate (molar ratio) ) = 40: 30: 30
Aqueous resin emulsion: acrylic resin emulsion, W-4627 (Tg 45 ° C.), W-4626 (Tg 20 ° C.), manufactured by Toyochem Co., Ltd. PEG: manufactured by Wako Pure Chemical Industries, Ltd., polyethylene glycol (average molecular weight 20, 000)
・ Glycerin: Wako Pure Chemical Industries, Ltd. ・ Diethylene glycol: Wako Pure Chemical Industries, Ltd. ・ Orphine E1010: Ethylene oxide adduct of acetylene glycol, manufactured by Nissin Chemical Industry ・ Orphine EXP. 4001: Ethylene oxide adduct of acetylene glycol, manufactured by Nissin Chemical Industry Co., Ltd. ・ Orphine EXP. 4123: Ethylene oxide adduct of acetylene glycol, manufactured by Nissin Chemical Industry Co., Ltd. • Olfine EXP. 4300: Ethylene oxide adduct of acetylene glycol, manufactured by Nissin Chemical Industry Co., Ltd. • Silface SAG002: Polyether-modified silicone, manufactured by Nissin Chemical Industry Co., Ltd. • Silface SAG503A: Polyether-modified silicone, Nisshin Chemical Industry Made by

(Preparation of treatment liquids A to D)
After mixing each component described in Table 2, treatment liquids A to D were prepared by filtering with a filter having a pore size of 1 μm (manufactured by ADVANTEC, A100A090C).
In Table 2, the numerical value of each component means weight% as a solid content, and the amount of ion-exchanged water is added as the balance so that each component becomes the weight%.

Each component used in Table 2 is as follows.
・ Pyrrolidone carboxylic acid: Ajinomoto Co., Inc. ・ Polyaluminum chloride: Central Glass Co., Ltd. ・ Viniblanc 701FE50: Cationic polymer, Nissin Chemical Industry Co., Ltd. ・ Glycerin: Wako Pure Chemical Industries, Ltd. ・ Diethylene glycol : Wako Pure Chemical Industries, Ltd.-Olphine E1010: Ethylene oxide adduct of acetylenic diol, manufactured by Nissin Chemical Industry Co., Ltd.

(Examples 1 to 4 and Comparative Examples 1 to 5)
<Print test>
A printing apparatus having a printing speed of 25 m / min and a drying process comprising a drum heater (set temperature of 100 ° C.) and warm air (set temperature of 100 ° C.) was used. The print head used was a 600 dpi piezo head (maximum droplet volume of 11 pl). The treatment liquid was first applied with an IJ head (2.0 g / m ² ), and then a solid image was printed with each color ink.
The printing media used were Oki Paper Co., Ltd. OK Top Coat + (continuous amount 43 kg, maximum liquid absorption 15 ml / m ² ) and Nippon Paper Industries Co., Ltd. Aurora Coat.

<Rubbing resistance evaluation>
The obtained image was evaluated for abrasion resistance.
An ink-permeable penetrating paper NIJ70 (manufactured by Oji Paper Co., Ltd.) was layered on the obtained solid image portion and dragged with a load of 20N.
The evaluation criteria are as follows. The same evaluation was made regardless of which recording medium was used.
G1: There is no peeling, and the optical density of the transfer part is 0.03 or less. G2: The image is not peeled off, but the optical density of the transfer part exceeds 0.03. G3: The image is peeled off. Measuring instrument: ROMIX CS Co. , Ltd., Ltd. Manufactured by X-Rite 504 spectral densitometer.

(Preparation of inkjet inks 7 to 13)
The components listed in Table 4 were mixed to prepare inkjet inks 7 to 13.
The measured values of static surface tension and dynamic surface tension are summarized in Table 4.
In Table 4, the numerical value of each component means weight% as a solid content, and the amount of ion-exchanged water was added as the balance so that each component becomes the weight%.
After mixing the components described in Table 4, inkjet inks 7 to 13 were prepared by filtering with a filter having a pore size of 5 μm (manufactured by ADVANTEC, A500A090C).

(Preparation of treatment liquid E)
After the following components were mixed, the treatment liquid E was prepared by filtering with a filter having a pore size of 1 μm (ADVANTEC, A100A090C).
In addition, the numerical value of each component means the weight% as solid content, and the quantity of ion-exchange water was added as the remainder so that each component might be the said weight%.
Malonic acid: 5
Lithium hydroxide: 2
Glycerin: 8
Diethylene glycol: 8
Olphin E1010: 1.5
Ion-exchange water: balance

(Examples 5 to 11 and Comparative Example 6)
Evaluation was performed in the same manner as in Example 1. The evaluation results are shown in the following table.

10: inkjet recording device 12: image recording unit 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 devices 122, 122K, 122Y, 122M, 122C: discharge heads 123, 123K, 123Y, 123M, 123C: ink Cartridge 124: Conveyance path 126: Drying drum 128: Hot air blower P: Recording medium

Claims (4)

Treatment liquid application means for applying the treatment liquid on the recording medium; and
Including ejection means for ejecting ink for inkjet recording onto a recording medium;
When the ink for inkjet recording contains at least a colorant, polymer particles, a surfactant, a water-soluble organic solvent, and water, and the dynamic surface tension is measured by the maximum bubble pressure method, the ink after 1 msec. The dynamic surface tension is 32 mN / m or less, the change range of the dynamic surface tension from 1 msec to 1 sec is 0.2 mN / m to 3.0 mN / m,
The surfactant contains two or more acetylene glycol ethylene oxide adducts,
The water-soluble organic solvent contains diethylene glycol;
The treatment liquid contains water and a flocculant ,
The recording medium has a maximum liquid absorption amount of the ink for ink jet recording of 15 mL / m ² or less at a contact time of 500 msec as measured by a dynamic operation absorption meter.
Image recording device . The image recording apparatus according to claim 1, wherein the aggregating agent is selected from the group consisting of an organic acid, a polyvalent metal salt, and a cationic polymer. As before heard inkjet recording ink, to chromatic ink for ink jet recording magenta ink for ink jet recording cyan, yellow ink for ink jet recording, and a black ink for ink jet recording, according to claim 1 Or the image recording apparatus of 2. Furthermore, the treatment liquid and / or a drying means for heating and drying the ink-jet recording ink, an image recording apparatus according to any one of claims 1-3.

Images