JP2018083930A - Ink, ink container, image formation method, image formation device, image formed article and liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink capable of high quality image formation with suppressing beading and good in image fixability and discharge stability to not only plain papers, but also general-purpose printing papers.SOLUTION: There is provided an ink containing a coloring material, an organic solvent, a resin particle and water, the resin particle consists of a resin having a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group, at least one kind of organic solvents having solubility parameter of 8.96 or more and less than 11.8 is contained as the organic solvent, dynamic surface tension A of the ink at 25°C and surface lifetime by a maximum foaming pressure method of 15 msec is 34.0 mN/m or less and the dynamic surface tension A and static surface tension B of the ink at 25°C satisfy 10.0%≤[(A-B)/(A+B)]×100≤19.0%.SELECTED DRAWING: None

Description

  The present invention relates to ink, an ink container, an image forming method, an image forming apparatus, an image formed article, and a liquid ejection apparatus.

  In recent years, an image forming method using an ink jet method has been rapidly spread because a color image can be easily recorded and the running cost is low.

As the ink used in the image forming method, an aqueous pigment ink in which a pigment is finely dispersed and dispersed in water has attracted attention. The pigment may have a composition close to that of a color material used in a general commercial printing ink, and it is expected that the texture of the printed matter can be approximated to commercial printing. However, when the aqueous pigment ink is used to record on coated paper for commercial printing or publication printing, there is a problem that beading occurs because the ink cannot be absorbed in time.
Further, there is a problem that the image recorded on the coated paper for printing is transferred to the interleaf side in the roll state in the winding process after the printing process.

  Therefore, the applicant of the present application has previously proposed an ink for ink jet recording containing water, a water-soluble organic solvent, a surfactant, and a coloring material (see, for example, Patent Documents 1 and 2).

  The present invention provides an ink that is capable of forming a high-quality image with suppressed beading, as well as plain paper as well as general-purpose printing paper, and having good image fixing properties and ejection stability. For the purpose.

The ink of the present invention as a means for solving the above problems is an ink containing a coloring material, an organic solvent, resin particles, and water,
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and has a dynamic surface tension A of 34.0 mN at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method. / M or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are as follows: 10.0% ≦ [(A−B) / (A + B)] × Satisfies 100 ≦ 19.0%.

  According to the present invention, it is possible to form a high-quality image with suppressed beading on general-purpose printing paper as well as plain paper, and provide an ink having good image fixing property and ejection stability. can do.

FIG. 1 is a diagram showing an example of a recording apparatus using the ink of the present invention. FIG. 2 is a perspective view of a main tank that accommodates the ink of the present invention. FIG. 3 is a schematic view showing an example of the liquid ejection apparatus of the present invention. FIG. 4 is an external perspective view showing an example of an ink discharge head in the ink discharge apparatus of the present invention. FIG. 5 is a cross-sectional explanatory view in a direction orthogonal to the nozzle arrangement direction of the ink discharge head in the ink discharge apparatus of the present invention.

(ink)
The ink of the present invention contains a coloring material, an organic solvent, resin particles, and water, preferably contains a surfactant, and further contains other components as necessary.
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group.
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and the dynamic surface tension A of the ink is 25.degree. 0 mN / m or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are expressed by the following formula: 10.0% ≦ [(A−B) / (A + B)] X100 ≦ 19.0% is satisfied.

  In the ink of the present invention, the relationship between the dynamic surface tension at the surface life of 15 msec by the maximum bubble pressure method and the static surface tension of the ink is not optimized in the conventional ink. This is based on the knowledge that there is a problem that the ink repellent film of the nozzle plate is easily wetted and the ejection stability is lowered due to the ink adhering to the nozzle.

The ink of the present invention is a resin particle in which the resin particles include a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and has a dynamic surface tension A of 34.0 mN at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method. / M or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are as follows: 10.0% ≦ [(A−B) / (A + B)] × By satisfying 100 ≦ 19.0%, sufficient wettability of the ink to the recording medium can be secured, and the ink is also applied to the coated paper having poor ink-absorbing property such as a general-purpose printing paper. It penetrates quickly, and pigment aggregation abruptly occurs during the drying process after ink landing on the paper surface, thereby increasing the viscosity and suppressing beading.

  General polyurethane resin particles and acrylic resin particles become unstable when in contact with an organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and the storage stability and ejection stability of ink cannot be ensured. As a result of intensive studies by the inventor on this point, the resin particles contain a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group, thereby increasing the stability of the resin particles with respect to the organic solvent. Ink storage stability is improved, and ejection stability is also improved. Furthermore, it has been found that blocking resistance, which is one of fixing properties, is also improved.

The dynamic surface tension A of the ink at 25 ° C. and the maximum bubble pressure method at a surface life of 15 msec is 34.0 mN / m or less, more preferably 30.1 mN / m or less, preferably 30.0 mN / m or less, 25 It is more preferably from 0.0 mN / m to 30.0 mN / m, particularly preferably from 27.5 mN / m to 30.0 mN / m.
By setting the dynamic surface tension A to 34.0 mN / m or less, the wettability and penetrability in general-purpose printing paper are improved, and the effect of reducing beading and color bleeding is enhanced. In addition, color development and white spots on plain paper can be improved.
The dynamic surface tension of the ink according to the maximum bubble pressure method at a surface life of 15 msec can be measured at 25 ° C. using, for example, SITA DynoTester (manufactured by SITA).

The dynamic surface tension A and the static surface tension B of the ink at 25 ° C. satisfy the following formula: 10.0% ≦ [(A−B) / (A + B)] × 100 ≦ 19.0% It is preferable to satisfy the following formula: 10.7% ≦ [(A−B) / (A + B)] × 100 ≦ 17.3%, preferably 12.0% ≦ [(A−B) / (A + B)] It is more preferable to satisfy x100 ≦ 17.0%.
The dynamic surface tension A and the static surface tension B of the ink at 25 ° C. satisfy the following formula: 10.0% ≦ [(A−B) / (A + B)] × 100 ≦ 19.0% By satisfying, the balance between the dynamic surface tension A and the static surface tension B in the ink can be optimized, the ink repellent film of the nozzle plate of the inkjet head is difficult to get wet, and discharge stability can be secured, An extremely stable ink can be obtained in which nozzle missing does not occur during continuous ejection.
The dynamic surface tension A of the ink at 25 ° C. and the maximum bubble pressure method at a surface life of 15 msec is 34.0 mN / m or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. In order to satisfy the following formula, 10.0% ≦ [(A−B) / (A + B)] × 100 ≦ 19.0%, the type and content of the surfactant in the ink are adjusted as appropriate. Can be achieved.
Among the types of the surfactant, a polyether-modified siloxane compound described later is preferable. Moreover, as content of the said surfactant, the range mentioned later is preferable.
The static surface tension B at 25 ° C. of the ink is preferably 20.0 mN / m or more and 30.0 mN / m or less, more preferably 20.8 mN / m or more and 26.8 mN / m or less.
When the static surface tension is 20.0 mN / m or more and 30.0 mN / m or less, the ink permeability can be increased, the effect of reducing cockling and curling is increased, and the penetration drying for plain paper printing. Becomes better.
The static surface tension of the ink can be measured at 25 ° C., for example, using a fully automatic surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

<Organic solvent>
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8. The solubility parameter is preferably 9 or more and less than 11.8, more preferably 9.03 or more and 11.3 or less.
By containing an organic solvent having a solubility parameter of 8.96 or more and less than 11.8, it is possible to suppress the occurrence of beading even on general-purpose printing paper.
The organic solvent in the present invention is a general term for organic compounds classified as a solvent, and is an organic compound classified as a solvent even if it is a substance represented by a functional expression such as a wetting agent or a penetrant. As long as it is included.

Here, the solubility parameter (SP value) refers to a numerical value of how easily each other is soluble. The SP value is expressed by a square root of an attractive force between molecules, that is, an aggregation energy density CED (Cohesive Energy Density). The CED is the amount of energy required to evaporate 1 mL.
The solubility parameter (SP value) is defined by the regular solution theory introduced by Hildebrand and is a measure of the solubility of the binary solution.
Although there are various theories on the calculation method of the SP value, the Fedors method generally used in the present invention is used.
By the Fedors method, the SP value can be calculated using the following mathematical formula (B).

[Formula (B)]
SP value (dissolution parameter) = (CED value) ^1/2 = (E / V) ^1/2
However, in the above formula (B), E is the molecular aggregation energy (cal / mol), V is the molecular volume (cm ³ / mol), the evaporation energy of the atomic group is Δei, and the molar volume is Δvi, It is shown by the mathematical formula (C) and the following mathematical formula (D).

[Formula (C)]
E = ΣΔei

[Formula (D)]
V = ΣΔvi

In addition, as various data of the said calculation method, evaporation energy (DELTA) ei of each atomic group, and molar volume (DELTA) vi, the data as described in "Fundamental theory of adhesion | attachment" (Akira Imoto writing, a polymer publication society, Chapter 5) are used. be able to.
For those in which —CF ₃ group or the like is not shown, R.I. F. Fedors, Polym. Eng. Sci. 14, 147 (1974).

  The organic solvent having a solubility parameter (SP value) of 8.96 or more and less than 11.8 is selected from an amide compound represented by the following general formula (I) and an oxetane compound represented by the following general formula (II). At least one is more preferable.

[General Formula (I)]
However, in said general formula (I), R 'shows a C4-C6 alkyl group.

[General Formula (II)]
In the general formula (II), R ″ represents an alkyl group having 1 to 2 carbon atoms.

  Specific examples of the amide compound represented by the general formula (I) or the oxetane compound represented by the general formula (II) include the following compounds.

[Structural formula (1), SP value: 9.03]

[Structural formula (2), SP value: 9.00]

[Structural formula (3), SP value: 8.96]

[Structural formula (4), SP value: 11.3]

[Structural formula (5), SP value: 11.79]

  Examples of the organic solvent having the solubility parameter (SP value) of 8.96 or more and less than 11.8 include, in addition to the amide compound represented by the general formula (I) and the oxetane compound represented by the general formula (II), for example. , 3-ethyl-oxetanemethanol (SP value: 11.31), β-methoxy-N, N-dimethylpropionamide (SP value: 9.19), β-butoxy-N, N-dimethylpropionamide (SP value) : 9.03), diethylene glycol monoethyl ether (SP value: 10.14), diethylene glycol monoisopropyl ether (SP value: 9.84), diethylene glycol monoisobutyl ether (SP value: 9.44), methyl polyglycol (SP Value: 9.77), polypropylene glycol 250 (SP value: 10.46), polyp Pyrene glycol 400 (SP value: 9.77), tripropylene glycol methyl ether (SP value: 9.77), polypropylene glycol glyceryl ether (SP value: 10.29), polypropylene glycol monomethyl ether (SP value: 9. 05), polybutylene glycol 500 (SP value: 9.51), methylpropylene triglycol (SP value: 9.43), (2EO) (2PO) butyl ether (SP value: 9.11), (5EO) (5PO) ) Butyl ether (SP value: 9.04), diethylene glycol mono-n-butyl ether (SP value: 9.86), diethylene glycol monovinyl ether (SP value: 10.90), diethylene glycol monomethyl ether (SP value: 10.34), Diethylene glycol Butyl ether (SP value: 9.77), triethylene glycol monomethyl ether (SP value: 10.12), diethylene glycol monoethyl ether acetate (SP value: 9.31), N-methyldiisopropanolamine (SP value: 11. 29), γ-butyrolactone methacrylate (SP value: 11.15), methyl acetate (SP value: 9.39), ethyl acetate (SP value: 9.26), n-propyl acetate (SP value: 9.17) ), N-propyl alcohol (SP value: 10.52), butyl acetate (SP value: 9.09), methylpropylene glycol (SP value: 9.73), propylene glycol-n-propyl ether (SP value: 9) .82), 1-methoxy-2-propyl acetate (SP value: 9.11), methyl Lopylene glycol acetate (SP value: 9.11), propylpropylene glycol (SP value: 9.82), ethylene glycol monomethyl ether acetate (SP value: 9.39), cyclohexanol acetate (SP value: 0.011), Butylpropylene glycol (SP value: 9.69), 3-methoxybutyl acetate (SP value: 9.05), 3-methoxybutanol (SP value: 9.98), 3-methoxy-1-propanol (SP value: 10.41) 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine (SP value: 10.21), ethylene glycol mono-n-butyl ether acetate (SP value: 9.15), dipropylene glycol Methyl ether (SP value: 9.69), 1,6-hexanediol diacetate (SP value) : 9.99), butyl propylene diglycol (SP value: 9.43), 1,4-butanediol diacetate (SP value: 10.25), propylpropylene diglycol (SP value: 9.50), 1 , 3-butylene glycol diacetate (SP value: 10.11), diethylene glycol monobutyl ether acetate (SP value: 9.19), propylene glycol diacetate (SP value: 10.27), dipropylene glycol methyl ether acetate (SP Value: 8.99). These may be used individually by 1 type and may use 2 or more types together.

  As the organic solvent, in addition to the amide compound represented by the general formula (I) and the oxetane compound represented by the general formula (II), a solubility parameter (SP value) of 11.8 or more and 14.0 or less can be used. It is preferable to use a monohydric alcohol or a penetrant.

Examples of the polyhydric alcohol having a solubility parameter (SP value) of 11.8 or more and 14.0 or less include 3-methyl-1,3-butanediol (SP value: 12.05) and 1,2-butanediol. (SP value: 12.8), 1,3-butanediol (SP value: 12.75), 1,4-butanediol (SP value: 12.95), 2,3-butanediol (SP value: 12) .55), 1,2-propanediol (SP value: 13.5), 1,3-propanediol (SP value: 13.72), 1,2-hexanediol (SP value: 11.8), 1 , 6-hexanediol (SP value: 11.95), 3-methyl-1,5-pentanediol (SP value: 11.8), triethylene glycol (SP value: 12.12), diethylene glycol (SP value: 13.02) Etc., and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, 3-methyl-1,3-butanediol (SP value: 12.05), 1,2-butanediol (SP value: 12.8), 1,3-butanediol (SP value: 12.2. 75), 1,4-butanediol (SP value: 12.95), 2,3-butanediol (SP value: 12.55), 1,2-propanediol (SP value: 13.5), 1, 3-propanediol (SP value: 13.72) is preferable, and 1,2-butanediol (SP value: 12.8) and 1,2-propanediol (SP value: 13.5) are more preferable.

The total content of the polyhydric alcohol having the solubility parameter (SP value) of 11.8 or more and 14.0 or less, the amide compound represented by the general formula (I) and the oxetane compound represented by the general formula (II) 30 mass% or more and 60 mass% or less are preferable with respect to the whole quantity.
When the content is 30% by mass or more, beading or color bleeding between colors may be suppressed on the general-purpose printing paper. When the content is 60% by mass or less, the image quality is good and the ink viscosity is low. It becomes appropriate and discharge stability is improved.

Examples of the penetrant include a polyol compound and a glycol ether compound having a solubility parameter (SP value) of 8.96 or more and less than 11.8, and having 8 to 11 carbon atoms.
Among these, 1,3-diol compounds represented by the following general formula (VII) are preferable, and 2-ethyl-1,3-hexanediol (SP value: 10.6), 2,2,4-trimethyl- 1,3-pentanediol (SP value: 10.8) is particularly preferred.

[General Formula (VII)]
However, in the general formula (VII), R ′ is either a methyl group or an ethyl group, R ″ is either a hydrogen atom or a methyl group, and R ′ ″ is an ethyl group or a propyl group. Either.

  Examples of other polyol compounds include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1,2-diol Etc.

  The content of the penetrant is preferably 0.5% by mass to 4% by mass, more preferably 1% by mass to 3% by mass, and particularly preferably 1% by mass to 2% by mass with respect to the total amount of the ink. . When the content is 0.5% by mass or more, an ink permeability effect is obtained, and an effect is obtained on image quality. On the other hand, when the content is 4% by mass or less, the initial viscosity of the ink is appropriate.

The content of the organic solvent having the solubility parameter of 8.96 or more and less than 11.8 is preferably 10% by mass or more, and more preferably 20% by mass or more and 60% by mass or less with respect to the total amount of the ink.
When the content is 10% by mass or more, occurrence of beading on general-purpose printing paper is suppressed, and the effect of suppressing color bleeding between colors is improved. On the other hand, when the content is 60% by mass or less, the image quality is improved, the ink viscosity is appropriate, and the ejection stability is improved.

The organic solvent preferably does not contain “polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C. and a relative humidity of 80%”.
The equilibrium water content is a potassium chloride / sodium chloride saturated aqueous solution, and the temperature and humidity in the desiccator is maintained at a temperature of 23 ° C. ± 1 ° C. and a relative humidity of 80% ± 3%. The obtained petri dish was stored, and the equilibrium water content was determined from the following formula A.
[Formula A]
Equilibrium moisture content (%) = [moisture content absorbed in organic solvent / (organic solvent + water content absorbed in organic solvent)] × 100
When the organic solvent contains “polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C. and a relative humidity of 80%”, the coated paper having poor ink-absorbing property and having a coating layer such as general-purpose printing paper As a result, the permeation of ink is delayed, drying after landing on the paper surface is delayed, and beading may occur.
The “polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C. and a relative humidity of 80%” is disclosed in JP 2012-207202 A (Patent Document 1) and JP 2014-94998 A (Patent Document 2). It is used by.
Examples of the “polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C. and a relative humidity of 80%” include 1,2,3-butanetriol (equilibrium water content: 38%), 1,2,4, and the like. -Butanetriol (equilibrium water content: 41%), glycerin (equilibrium water content: 49%, SP value 16.38), diglycerin (equilibrium water content: 38%), triethylene glycol (equilibrium water content: 39%, SP value 15.4), tetraethylene glycol (equilibrium water content: 37%), diethylene glycol (equilibrium water content: 43%), 1,3-butanediol (equilibrium water content: 35%) and the like.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used. Among these, it is preferable to use a pigment from the point of weather resistance.
Examples of the pigment include organic pigments and inorganic pigments.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is preferable.

The carbon black (Pigment Black 7) is produced by a known method such as a contact method, a furnace method, or a thermal method, and examples thereof include channel black, furnace black, gas black, and lamp black.
Commercially available products of the carbon black include, for example, Regal (registered trademark), Black Pearls (registered trademark), Elftex (registered trademark), Monarch (registered trademark), Regal (registered trademark), Mogul (registered trademark), and Vulcan (registered trademark). Carbon black available from Cabot Corporation under the registered trademark (for example, Black Pearls 2000, 1400, 1300, 1100, 1000, 900, 880, 800, 700, 570, Black Pearls) L, Elftex 8, Monarch 1400, 1300, 1100, 1000, 900, 900, 880, 800, 700, Mogu L, Regal 330, 400, 660, Vulcan P); S NSIJET Black SDP100 (SENSIENT Co., Ltd.), (made by SENSIENT Inc.) SENSIJET Black SDP1000, (manufactured by SENSIENT Inc.) SENSIJET Black SDP2000 and the like. These may be used individually by 1 type and may use 2 or more types together.

Examples of the organic pigment include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are preferable.
Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

  Specific examples of the organic pigment include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 128, 139, 150, 151, 155, 153, 180, 183, 185, 213, C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 219, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3 (phthalocyanine blue), 16, 17: 1, 56, 60, 63; I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, and the like. These may be used individually by 1 type and may use 2 or more types together.

The specific surface area of the pigment is not particularly limited and may be appropriately selected depending on the intended purpose. It is preferably 10 m ² / g or more and 1,500 m ² / g or less, and preferably 20 m ² / g or more and 600 m ² / g or less. More preferred is 50 m ² / g or more and 300 m ² / g or less.
If the desired surface area is not met, the pigment can be adjusted by size reduction or grinding (eg, ball milling, or jet milling, or sonication) to achieve a relatively small particle size. it can.
The cumulative 50% particle diameter (D ₅₀ ) of the pigment is preferably 10 nm or more and 200 nm or less in the ink.

The pigment is preferably a water-dispersible pigment. Examples of the water-dispersible pigment include (1) surfactant dispersion in which the pigment is dispersed with a surfactant, (2) resin dispersion in which the pigment is dispersed with a resin, (3) Resin coating dispersion in which the surface of the pigment is coated with a resin, (4) Self-dispersing pigment having a hydrophilic group on the pigment surface, and the like.
Among these, the resin-coated pigment in which the surface of the pigment of (3) is coated with a resin and the pigment surface of (4) are hydrophilic because they have high storage stability over time and can suppress an increase in viscosity during water evaporation. Self-dispersing pigments provided with groups are preferred.

As the self-dispersing pigment (4) having a hydrophilic functional group, anionically charged pigments are suitable. Examples of the anionic functional _{group, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -CONM 2, -SO 3 NM 2, -NH-C 6 H 4 -COOM, -NH- _{C 6 H 4 -SO 3 M,} -NH-C 6 H 4 -PO 3 HM, -NH-C 6 H 4 -PO 3 M 2, -NH-C 6 H 4 -CONM 2, -NH-C 6 H ₄ —SO ₃ NM _{2 and the} like can be mentioned, and examples of the counter ion M include alkali metal ions and quaternary ammonium ions, with quaternary ammonium ions being preferred.

Examples of the quaternary ammonium ion include tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, benzyltriethylammonium ion, benzyltriethylammonium ion, and tetrahexylammonium ion. Can be mentioned. Among these, tetraethylammonium ion, tetrabutylammonium ion and benzyltrimethylammonium ion are preferable, and tetrabutylammonium ion is more preferable.
The use of the self-dispersing pigment having the hydrophilic functional group and the quaternary ammonium ion is expected to show the affinity in the water-rich ink and the organic solvent-rich ink in which the water has evaporated, and to keep the dispersion of the pigment stable. Is done.

  Among the self-dispersing pigments, an ink using a pigment modified with at least one of a geminal bisphosphonic acid group and a geminal bisphosphonic acid group has excellent redispersibility after drying, and therefore does not print for a long time. Even when the moisture of the ink near the ink jet head nozzle evaporates, clogging does not occur, and good printing can be easily performed with a simple cleaning operation. Furthermore, since the storage stability with time is high and the increase in viscosity at the time of water evaporation is suppressed, the ink fixing property and the ejection reliability in the head maintenance device are also very excellent.

Specific examples of the phosphonic acid group or phosphonic acid group include any of the following structural formulas (i) to (iv).
However, in the structural formula (iii), X ⁺ represents Li ⁺ , K ⁺ , Na ⁺ , NH ₄ ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H _{7) 4} ⁺ and _{N (C} 4 H ₉₎ ^{4 +} represents any.

However, in the structural formula (iv), X ⁺ represents Li ⁺ , K ⁺ , Na ⁺ , NH ₄ ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H _{7) 4} ⁺ and _{N (C} 4 H ₉₎ ^{4 +} represents any.

-Pigment surface modification treatment-
Here, the modification treatment of the pigment surface will be described taking the case of a geminal bisphosphonic acid group as an example. Examples of the reforming method include the following method A and method B.
[Method A]
20 g of carbon black, 20 mmol of the compound of the following structural formula (v) or structural formula (vi), and 200 mL of ion-exchange high-purity water are mixed with a Silverson mixer (6000 rpm) in a room temperature environment. If the pH of the resulting slurry is higher than 4, 20 mmol of nitric acid is added. After 30 minutes, sodium nitrite (20 mmol) dissolved in a small amount of ion-exchanged high purity water is slowly added to the above mixture. Furthermore, when the mixture is heated to 60 ° C. with stirring and reacted for 1 hour, a modified pigment in which a compound of the following structural formula (v) or structural formula (vi) is added to carbon black is generated. Next, when the pH is adjusted to 10 with an aqueous NaOH solution, a modified pigment dispersion is obtained after 30 minutes. Next, ultrafiltration using a dialysis membrane is performed using the dispersion and ion-exchanged high-purity water, and further, a modified pigment dispersion in which solid content is concentrated by ultrasonic dispersion is obtained.

[Method B]
A ProcessAll 4HV mixer (4 L) is charged with 500 g of dry carbon black, 1 L of ion-exchange high purity water and 1 mol of the compound of the following structural formula (v) or structural formula (vi). The mixture is then mixed vigorously at 300 rpm while warming to 60 ° C. for 10 minutes. To this was added a 20% aqueous sodium nitrite solution [1 molar equivalent based on the compound of structural formula (v) or structural formula (vi)] over 15 minutes and mixed for 3 hours while warming to 60 ° C. Stir.
The reaction product was taken out while being diluted with 750 mL of ion-exchange high-purity water, ultrafiltered through a dialysis membrane using the resulting modified pigment dispersion and ion-exchange high-purity water, and further solidified by ultrasonic dispersion. A modified pigment dispersion is obtained. Furthermore, when there are many coarse particles, it is preferable to remove them using a centrifuge or the like.

[Structural Formula (v)]

[Structural Formula (vi)]

You may add a pH adjuster to the obtained modified pigment dispersion as needed. As the pH adjusting agent, the same one as the pH adjusting agent for ink described later can be used. Of these, Na ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H ₇ ) ₄ ⁺ , and N (C ₄ H ₉ ) ₄ ⁺ are preferable.
When the treatment with a pH adjuster is performed, at least a part of the compound of the structural formula (v) or the structural formula (vi) is a salt thereof (a compound corresponding to the structural formula (iii) or the structural formula (iv)). ).

The resin-coated pigment obtained by coating the surface of the pigment (3) with a resin is preferably a resin emulsion containing a pigment in a resin.
The resin emulsion containing a pigment in the resin is one in which the pigment is encapsulated in the resin, or one in which the pigment is adsorbed on the surface of the resin. In this case, it is not necessary for all the pigments to be encapsulated or adsorbed, and the pigments may be dispersed in the emulsion as long as the effects of the present invention are not impaired.
Examples of the resin that forms the resin emulsion include vinyl resins, polyester resins, polyurethane resins, and the like. Particularly preferably used resins are vinyl resins and polyester resins. The resin currently disclosed by 53897 gazette and Unexamined-Japanese-Patent No. 2001-139849 can be quoted.

In this case, a general organic pigment or a composite pigment obtained by coating inorganic pigment particles with an organic pigment or carbon black can be preferably used. The composite pigment can be produced by a method of depositing an organic pigment in the presence of inorganic pigment particles, a mechanochemical method of mechanically mixing and grinding an inorganic pigment and an organic pigment, or the like.
Further, if necessary, an adhesive layer between the inorganic pigment and the organic pigment can be improved by providing a layer of an organosilane compound formed from polysiloxane and alkylsilane between the inorganic pigment and the organic pigment.

The organic pigment and the inorganic pigment are not particularly limited, and can be appropriately selected from those described above.
The mass ratio between the inorganic pigment particles and the organic pigment or carbon black as the colorant is preferably 3: 1 to 1: 3, and more preferably 3: 2 to 1: 2.
When the amount of the coloring material is small, the color developability and coloring power may be lowered, and when the amount of the coloring material is large, the transparency and the color tone may be deteriorated.
Color material particles obtained by coating such inorganic pigment particles with an organic pigment or carbon black include silica / carbon black composite material manufactured by Toda Kogyo Co., Ltd., silica / phthalocyanine PB15: 3 composite material, silica / disazo yellow composite material, Silica / quinacridone PR122 composite material or the like can be suitably used because it has a small primary average particle size.
Here, when inorganic pigment particles having a primary particle size of 20 nm are coated with an equal amount of organic pigment, the primary particle size of the pigment is about 25 nm. If a primary dispersant can be dispersed using a suitable dispersant for this, a very fine pigment-dispersed ink having a dispersed particle diameter of 25 nm can be produced.
In the composite pigment, not only the organic pigment on the surface contributes to the dispersion, but also the properties of the inorganic pigment at the center appear through the thin layer of the organic pigment with a thickness of 2.5 nm, so that both can be dispersed and stabilized at the same time. The selection of the pigment dispersant is also important.

  The content of the coloring material is preferably 1% by mass or more and 15% by mass or less, and more preferably 2% by mass or more and 10% by mass or less with respect to the total amount of the ink. When the content is 1% by mass or more, sufficient ink color development and image density can be obtained. In addition, if the content is 15% by mass or less, the ink does not thicken or the discharge property is deteriorated, which is economically preferable.

<Resin particles>
The resin particles include a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group.
The resin particles have excellent film-forming properties (image-forming properties) and have high solvent properties, high water resistance, and high weather resistance. With high solvent properties, the resin particles are difficult to swell against the solvent added to the ink. Thus, the fixing property is good, and it is useful for forming an image with high water resistance and high image density (high color development).
In the ink of the present invention, resin particles having a charge having the same polarity as the pigment as the colorant and containing a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group are added in the form of a resin emulsion. Is preferable

  The glass transition temperature (Tg) of the resin in the resin emulsion is preferably 15 ° C. or higher, more preferably 30 ° C. or higher, still more preferably 40 ° C. or higher, and the upper limit is preferably 100 ° C. or lower, preferably 70 ° C. or lower. It is more preferable.

The glass transition temperature (Tg) of the resin is theoretically derived from the following formula (I). Note that the calculation of the glass transition temperature (Tg) does not include a structural unit having an alkoxysilyl group.
[Formula (I)]
1 / Tg = [(W1 / Tg1) + (W2 / Tg2) +... (Wn / Tgn)] / 100
In the formula (I), W1 is the mass% of the monomer 1, Tg1 is the glass transition temperature (° K) of a homopolymer that can be formed only from the monomer 1, W2 is the mass% of the monomer 2, Tg2 is the glass transition temperature (° K) of the homopolymer that can be formed from monomer 2 alone, Wn is the mass% of monomer n, and Tgn is the glass transition temperature (° K) of the homopolymer that can be formed from monomer n only. is there. Here, W1 + W2 +... + Wn = 100.
In addition, when using what has a radically polymerizable unsaturated group as an emulsifier when superposing | polymerizing a radically polymerizable unsaturated monomer in an aqueous medium, identification of the structure of a radically polymerizable unsaturated monomer and a copolymer In the calculation of the glass transition temperature (Tg), an emulsifier having a radically polymerizable unsaturated group is not included in the monomer.

(1) The content of the structural unit having a carboxyl group (radical polymerizable unsaturated monomer having a carboxyl group) (a1) is preferably 0.1% by mass or more and 10% by mass or less in the resin.
Examples of the radical polymerizable unsaturated monomer (a1) having a carboxyl group include acrylic acid and methacrylic acid.

(2) The content of the structural unit having an alkoxysilyl group (a structural unit derived from a radically polymerizable unsaturated monomer having an alkoxysilyl group) (a2) is preferably 0.1% by mass or more in the resin. More preferably, the content is 1% by mass or more and 20% by mass or less. When the content is 0.1% by mass or more, the particle size distribution state of the formed resin particles by the dynamic light scattering method and the number counting method satisfies the above conditions, the OD value becomes appropriate, and image formation The wear resistance, fixability, and solvent resistance of the product are improved. Many of the alkoxysilyl groups are considered to be hydrolyzed during the formation of the resin emulsion and contribute to the formation of internal crosslinks in the resin particles. Moreover, it is thought that a part of said alkoxy silyl group contributes also to the interparticle bridge | crosslinking formation between resin particles, and the interparticle bridge | crosslinking formation of resin and a pigment. Therefore, when the content of the structural unit (a2) derived from the radical polymerizable unsaturated monomer having an alkoxysilyl group is 0.1% by mass or more, both intra-particle crosslinking and inter-particle crosslinking by the alkoxysilyl group are appropriate. And As a result, not only the OD value is low, but also the abrasion resistance, fixing property and solvent resistance of the image formed product are improved.

When 0.1 mass% or more of the structural unit (a2) derived from the radically polymerizable unsaturated monomer having an alkoxysilyl group is contained in the resin, both intraparticle crosslinking and interparticle crosslinking are improved. As a result, the OD value is also improved, and the abrasion resistance, fixability, and solvent resistance of the image formed product are also improved.
On the other hand, even if an attempt is made to form a resin emulsion using a resin containing an excess of the structural unit (a2) derived from the radically polymerizable unsaturated monomer having an alkoxysilyl group in an amount of more than 20% by mass, the alkoxysilyl group Since the structural unit derived from the radically polymerizable unsaturated monomer is rich in hydrophobicity, it becomes difficult to polymerize. Furthermore, since the structural unit derived from the radically polymerizable unsaturated monomer having an alkoxysilyl group is a crosslinking component, it is also a component that lowers the polymerization stability. In a normal emulsion polymerization, when the crosslinking component contains 20% by mass or more The particles are aggregated during the polymerization, and a stable resin emulsion cannot be obtained.

  Examples of the radical polymerizable unsaturated monomer (a2) having an alkoxysilyl group include γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, and vinyltrimethoxysilane. It is done.

  Examples of the monomer (a3) for controlling the glass transition temperature (Tg) of other resins include acrylic acid (homopolymer Tg: 106 ° C. or lower), methyl acrylate (homopolymer Tg: −8 ° C.), acrylic Acrylic acid esters such as ethyl acrylate (Tg of homopolymer: −20 ° C.), butyl acrylate (Tg of homopolymer: −45 ° C.), 2-ethylhexyl acrylate (Tg of homopolymer: −55 ° C.); Methacrylic acid (Tg of homopolymer: 228 ° C.), Methyl methacrylate (Tg of homopolymer: 100 ° C.), Ethyl methacrylate (Tg of homopolymer: 65 ° C.), Butyl methacrylate (Tg of homopolymer: 20 ° C.) 2-ethylhexyl methacrylate (Tg of homopolymer: −10 ° C.), cyclohexyl methacrylate (photo Methacrylic acid esters such as polymer Tg: 66 ° C .; vinyl acetate (Tg of homopolymer: 30 ° C.), vinyl esters such as tertiary vinyl carboxylate; heterocyclic vinyl compounds such as vinylpyrrolidone; ethylene, Α-olefins such as propylene; dienes such as butadiene; glycidyl methacrylate (Tg of homopolymer: 41 ° C.), glycidyl group-containing monomers such as allyl glycidyl ether; Amino group-containing monomers of carboxylic acid amide groups such as acrylamide (Tg of homopolymer: 150 ° C.); cyano group-containing monomers such as acrylonitrile (Tg of homopolymer: 96 ° C.); styrene (Tg of homopolymer) : 100 ° C), divinylbenzene (homopoly) Vinyl monomer such as Tg of Mer: 116 ° C.). These may be used alone or in combination of two or more.

  In order to obtain the resin emulsion, 0.1 to 5 parts by mass of an emulsifier with respect to a total of 100 parts by mass of the monomers (a1) to (a3) and the monomers (a1) to (a3) It is important to obtain a monomer pre-emulsion having a volume average particle diameter of monomer droplets of 0.5 μm or more and 10 μm or less from water by the number counting method.

In the emulsion polymerization, the monomer subjected to the polymerization is dissolved in minute amounts from the monomer droplets in water, and the polymerization proceeds in water. That is, the polymerization field of the emulsion polymerization is a micelle made of an emulsifier generated in an aqueous phase, not in a monomer droplet. Therefore, in order to obtain a resin emulsion having a uniform composition and particle size distribution, it is important to make the dissolution of the monomer subjected to polymerization in water smooth and constant.
The radical polymerizable unsaturated monomer (a2) having an alkoxysilyl group is a poorly water-soluble monomer rich in hydrophobicity. In order to polymerize the poorly water-soluble monomer (a2) rich in hydrophobicity uniformly and reliably, it is necessary to quickly dissolve the poorly water-soluble monomer (a2) in water from the monomer droplets. is there.
For this purpose, it is effective to use a monomer pre-emulsion in which the volume average particle diameter of the monomer droplets is from 0.5 μm to 10 μm, and the monomer pre-emulsion having a volume average particle diameter of from 0.5 μm to 5 μm. It is extremely effective to use an emulsion. When the volume average particle size of the monomer droplets in the monomer pre-emulsion is larger than 10 μm, the radically polymerizable unsaturated monomer (a2) having an alkoxysilyl group is difficult to dissolve into the water from the monomer droplets. As a result, the monomer (a2) is not reliably used for the formation of the resin particles, and is left behind to generate ultra coarse particles or aggregates of 1.5 μm or more by the number counting method.
The monomer pre-emulsion in such a particle size state can be formed, for example, using a batch homomixer, an ultrasonic emulsifier, a high-pressure homogenizer, or the like, and appropriately adjusting the stirring speed, frequency, pressure, and the like.
The smaller the particle size of the monomer pre-emulsion, the higher the dissolution rate of the monomer from the monomer droplets into water, which is preferable. However, it is generally difficult to obtain a monomer pre-emulsion having a volume average particle size smaller than 0.5 μm even using the apparatus.
The volume average particle diameter of the monomer pre-emulsion by the number counting method is preferably 0.5 μm or more and 10 μm or less.
The volume average particle size of the monomer pre-emulsion is diluted with distilled water so that the monomer concentration is about 0.001% by mass to 0.05% by mass, as in the case of checking the coarse particles of the resin emulsion. "(Manufactured by PARTICLE SIZING SYSTEMS, USA).

The emulsifier is 0.1 parts by mass or more and less than 5 parts by mass and preferably 1 part by mass or more and 3 parts by mass or less with respect to 100 parts by mass in total of the monomers (a1) to (a3). When the amount of the emulsifier is 5 parts by mass or more, the water resistance of the image formed product is lowered. On the other hand, when the amount of the emulsifier is less than 0.1 parts by mass, the dispersion state of the monomer pre-emulsion cannot be kept stable.
As the emulsifier, an anionic emulsifier can be used alone, or an anionic emulsifier and a nonionic emulsifier can be used in combination.
The emulsifier may be a reactive emulsifier having a radical polymerizable functional group, a non-reactive emulsifier having no radical polymerizable functional group, or a combination of both. You can also. In terms of improving the water resistance of the image-formed product, it is preferable to use a reactive emulsifier having a radical polymerizable functional group.

  The reactive emulsifier is an anionic or nonionic emulsifier having one or more unsaturated double bonds capable of radical polymerization in the molecule. For example, sulfosuccinate ester type (for example, Kao Corporation Company-made Latemul S-120P, S-180A, Sanyo Chemical Co., Ltd., Eleminol JS-2, etc.), alkylphenol ethers (commercially available products are Dai-ichi Kogyo Seiyaku AQUALON KH-20, RN-20, etc.) There is.

  Examples of the non-reactive emulsifier include anionic non-reactive emulsifiers such as polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene polycyclic phenyl ether sulfate, and polyoxyethylene alkyl ether sulfate; polyoxyethylene nonylphenyl Polyoxyethylene alkylphenyl ethers such as ether and polyoxyethylene octylphenyl ether; polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether and polyoxyethylene oleyl ether; polyoxyethylene distyrenation And polyoxypolycyclic phenyl ethers such as phenyl ether; and nonionic non-reactive emulsifiers such as polyoxyethylene sorbitan fatty acid ester.

Specifically, as an anionic non-reactive emulsifier, for example, Hytenol NF-08 [repeating number of ethylene oxide units (hereinafter referred to as “number of EO units”): 8], NF-17 (number of EO units: 17) [Daiichi Kogyo Seiyaku Co., Ltd.], Eleminol ES-12 (EO unit number: 6), ES-30 (EO unit number: 15), ES-70 (EO unit number: 35) [above, Sanyo Chemical Industries, Ltd.].
Nonionic non-reactive emulsifiers include, for example, Emulgen 1108 (number of EO units: 8), 1118S-70 (number of EO units: 18), 1135S-70 (number of EO units: 35), 1150S-70 (number of EO units) : 50) [above, manufactured by Kao Corporation].
The said non-reactive emulsifier may be used individually by 1 type, and may use 2 or more types together.

It is also important that the resin emulsion contains water, an emulsifier, and an aqueous polymerizable initiator, and the monomer pre-emulsion is dropped into a polymerization field that does not contain the monomer pre-emulsion, thereby radical polymerization.
Add a large amount of water and a part of the monomer pre-emulsion for dropping to the reaction vessel, add the remaining monomer pre-emulsion and the polymerization initiator for dropping, or add a large amount of water, the polymerization initiator and the monomer pre-drop for dropping. A method of putting a part of the emulsion in a reaction vessel and adding the remaining monomer pre-emulsion for dropping to the reaction vessel is a method that is routinely selected in producing a resin emulsion.

However, when the radically polymerizable monomer (a2) having a poorly water-soluble alkoxysilyl group is used as in the present invention, the monomer (a2) dissolved in water from the monomer droplets is supplied to the polymerization field and then polymerized. It is important to polymerize quickly without staying in the field as much as possible and to be absent as the monomer (a2). That is, the dissolution of the monomer (a2) and the rapid disappearance of the monomer (a2) promote the further dissolution of the monomer (a2), and the polymerization reaction proceeds smoothly.
Therefore, in the case of the present invention, it is important not to put a part of the monomer pre-emulsion in the reaction vessel. If a part of the monomer pre-emulsion is put in the reaction vessel, even if the remainder of the monomer pre-emulsion is dropped from the dropping tank, the poorly water-soluble monomer (a2) in the monomer that was initially present is consumed by the polymerization. Until then, the poorly water-soluble monomer (a2) in the monomer supplied by dripping stays in the polymerization field, and causes generation of ultra coarse particles and aggregates.
In addition, the polymerization field containing water, an emulsifier, and an aqueous polymerizable initiator as used in the present invention means that the above three parties exist when the monomers in the monomer pre-emulsion are polymerized. That is, water, an emulsifier, and an aqueous polymerizable initiator are placed in a reaction vessel provided with a heating means and a cooling means, and the monomer and pre-emulsion are added dropwise to the reaction vessel similar to the above. In this reaction vessel, the monomer pre-emulsion and the aqueous polymerizable initiator may be dropped from separate dripping tanks, respectively. Alternatively, water and an emulsifier are placed in the same reaction vessel, and the reaction vessel is filled with aqueous solution. A method of dropping a monomer pre-emulsion containing a polymerizable initiator may also be used.

As an emulsifier put into a reaction container, the thing similar to what was illustrated when obtaining a monomer pre-emulsion can be illustrated.
The total amount of the emulsifier constituting the monomer pre-emulsion and the emulsifier to be added to the reaction vessel is more than 0.1 parts by mass and not more than 5 parts by mass with respect to a total of 100 parts by mass of the monomers (a1) to (a3). is important. When the total amount of the emulsifier is more than 5 parts by mass, the water resistance of the image formed product is lowered. On the other hand, if the total amount of emulsifier is 0.1 parts by mass or less, the dispersion state of the resin emulsion cannot be kept stable.

  Examples of the radical polymerization initiator include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate.

  The amount of the polymerization initiator used is preferably 0.1 parts by mass or more and 1 part by mass or less, and preferably 0.2 parts by mass or more and 0.8 parts by mass or less with respect to 100 parts by mass of the total amount of monomers used for emulsion polymerization. More preferred. Water resistance and superposition | polymerization stability become favorable in the said usage-amount being 0.1 mass part or more and 1 mass part or less.

  As the redox initiator, a combination of a peroxide-based initiator and a reducing agent is effective. Examples of the peroxide initiator include perbutyl H (tertiary butyl hydroperoxide), perbutyl O (tertiary butyl peroxy-2-ethylhexanoate), cumene hydroperoxide, p-menthane hydroperoxide, and the like. Is mentioned. Examples of the reducing agent include Erbit N (sodium isoascorbate), L-ascorbic acid (vitamin C), sodium sulfite, sodium bisulfite, sodium pyrosulfite (SMBS), sodium hyposulfite (hydrosulfite), and the like. Can be mentioned.

  The resin emulsion can also be obtained by a method different from the method described above. For example, with a part of the monomer pre-emulsion in the reaction vessel, a part of the aqueous polymerizable initiator is dropped into the reaction vessel to initiate the polymerization reaction, and the poorly water-soluble property in the reaction vessel There is a method in which the monomer pre-emulsion and the remainder of the aqueous polymerizable initiator are dropped into a reaction vessel after the monomer including the monomer (a2) is sufficiently consumed by polymerization. In this method, although the monomer pre-emulsion exists at the time of starting the polymerization, the monomer pre-emulsion disappears during the polymerization, so that the generation of ultra coarse particles and aggregates can be suppressed. The monomer concentration in the reaction vessel at the start of polymerization is preferably 20% by mass or less. When the monomer concentration is 20% by mass or less, the reaction heat at the time of polymerization is appropriate, and the polymerization stability is good.

Any of the resin emulsions obtained by the various methods described above has an extremely small content of ultra coarse particles of 1.5 μm or more.
The resin emulsion is preferably used after being neutralized with a volatile base compound.
Examples of the volatile base compound include ammonia; examples of amines include monoethylamine, dimethylethanolamine, diethylethanolamine, and methylpropanolamine. These may be used alone or in combination of two or more.
In the resin emulsion, a hydrophilic organic solvent can be used as needed as long as the objects and effects of the present invention are not impaired.
The cumulative 50% particle diameter (D ₅₀ ) of the resin in the resin emulsion by dynamic light scattering method is preferably 50 nm or more and 200 nm or less, and the resin emulsion has 0.5 μm (= 500 nm) or more by dynamic light scattering method. It is preferable that no coarse particles are observed.
The cumulative 50% particle size (D ₅₀ ) is a particle size corresponding to 50% of the volume distribution cumulative amount of the particle size distribution curve obtained by the dynamic light scattering method. Specifically, the resin emulsion is diluted to a solid content of 0.01% by mass or more and 0.1% by mass or less, and “Microtrac UPA” (manufactured by Lees & Northrup) is used, and the cumulative particle size (D ₅₀ ) is 50%. Can be requested.

  The content of the resin particles is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 8% by mass or less in terms of solid content with respect to the total amount of the ink.

The fact that resin particles containing an alkoxysilyl group and a carboxy group as structural units is contained in the ink can be analyzed as follows.
<Resin sorting>
(1) First, in order to acidify the ink, 0.1N hydrochloric acid aqueous solution is added while stirring the ink with a magnetic stirrer, and the ink is acidified until the pH becomes about 4. The coagulated and precipitated solid is filtered with a Buchner funnel type glass filter (mesh roughness of 1.0 μm or less). Further, it is washed several times with high purity water.
(2) The washed aggregated precipitate is dried under reduced pressure for 3 hours while keeping it at 40 ° C. or lower with a vacuum dryer.
(3) The dried aggregated precipitate is put into a cylindrical filter paper, and Soxhlet extraction is performed for 5 hours using tetrahydrofuran (THF).
(4) The THF obtained as a solvent is removed from the extract obtained by Soxhlet extraction using a rotary evaporator.
(5) Further, the obtained residue is dried under reduced pressure for 3 hours while being kept at 30 ° C. or lower using a vacuum dryer.
<Analysis>
The dried residue is subjected to GC-MS, H ¹ -NMR, and IR spectrum analysis to analyze whether or not resin particles containing alkoxysilyl groups and carboxy groups as constituent units are contained in the ink. it can.

<Water>
As said water, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used, for example.
There is no restriction | limiting in particular as content in the ink of the said water, According to the objective, it can select suitably.

<Surfactant>
The surfactant preferably contains a polyether-modified siloxane compound.
By using the polyether-modified siloxane compound as a surfactant, the ink becomes difficult to get wet with the ink-repellent layer of the nozzle plate of the ink head, and ejection failure due to ink nozzle adhesion is prevented and ejection stability is improved.

  The polyether-modified siloxane compound has the following general formula (III) from the viewpoints of low dynamic surface tension, low penetrability, and leveling properties without impairing dispersion stability depending on the type of color material and the combination of the organic solvents. To at least one selected from the compounds represented by (VI).

[General Formula (III)]
However, in said general formula (III), m shows the integer of 0-23 and n shows the integer of 1-10. a represents an integer of 1 to 23, and b represents an integer of 0 to 23. R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[General Formula (IV)]
However, in said general formula (IV), m shows the integer of 1-8, c and d show the integer of 1-10. R ₂ and R ₃ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[General Formula (V)]
However, the general formula (V), e represents an integer from 1 to 8, _{R 4} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[General Formula (VI)]
However, in said general formula (VI), f shows the integer of 1-8. R ₅ represents a polyether group represented by the following general formula (a).

[General Formula (a)]
However, in said general formula (a), g shows the integer of 0-23, h shows the integer of 0-23, g and h do not become 0 simultaneously. R ₆ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

  Examples of the polyether-modified siloxane compound represented by the general formula (III) include, but are not limited to, compounds represented by the following structural formula.

[Structural Formula (VI)]

[Structural Formula (VII)]

[Structural Formula (VIII)]

[Structural Formula (IX)]

[Structural Formula (X)]

[Structural Formula (XI)]

[Structural Formula (XII)]

[Structural Formula (XIII)]

  Examples of the polyether-modified siloxane compound represented by the general formula (IV) include, but are not limited to, compounds represented by the following structural formula.

[Structural Formula (XIV)]

  Examples of the polyether-modified siloxane compound represented by the general formula (V) include, but are not limited to, compounds represented by the following structural formula.

[Structural Formula (XV)]

  Examples of the polyether-modified siloxane compound represented by the general formula (VI) include, but are not limited to, compounds represented by the following structural formula.

[Structural Formula (XVI)]

[Structural Formula (XVII)]

[Structural Formula (XVIII)]

  As said polyether modified siloxane compound, what was synthesize | combined suitably may be used and a commercial item may be used.

The method for synthesizing the polyether-modified siloxane compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, Patent Nos. 5101598, 5032325, 5661229, etc. Can be referred to.
Specifically, it can be synthesized by hydrosilylation reaction of (A) polyether and (B) organohydrogensiloxane.
Polyethers of the component _{(A), - (C n H 2n O} ) - ( In the formula, n represents 2 to 4.) Shows a polyoxyalkylene polymer represented by.
The polyoxyalkylene copolymer unit is preferably an oxyethylene unit-(C ₂ H ₄ O)-, an oxypropylene unit-(C ₃ H ₆ O)-, an oxybutylene unit-(C ₄ H ₈ O)-, Alternatively, mixed units thereof can be included. The oxyalkylene units may be arranged in any way and can form either block or random copolymer structures, but preferably form random copolymer groups. More preferably, the polyoxyalkylene comprises both oxyethylene units (C ₂ H ₄ O) and oxypropylene units (C ₃ H ₆ O) in the random copolymer.

The organohydrogensiloxane of the component (B) is an organopolysiloxane containing at least one silicon-bonded hydrogen (SiH) per molecule. Examples of the organopolysiloxane include (R ₃ SiO _0.5 ), (R ₂ SiO), (RSiO _1.5 ), and (SiO ₂ ) (wherein, R is independently an organic group or carbonized) And any number or combination of siloxy units (which are hydrogen groups).
When R of (R ₃ SiO _0.5 ), (R ₂ SiO), (RSiO _1.5 ) of the organopolysiloxane is a methyl group, the siloxy units are M, D, and T units, respectively. Whereas (SiO ₂ ) siloxy units are shown as Q units.
The organohydrogensiloxane has a similar structure but has at least one SiH present on the siloxy units.
Methyl-based siloxy units in the organohydrogensiloxane, ^{"M H"} siloxy units _(R 2 _{HSiO 0.5),} ^{"D H"} siloxy units (RHSiO), ^{"T H"} siloxy units _{(HSiO 1.5)} Can be shown as including.
The organohydrogensiloxane can include any number of M, M ^H , D, D ^H , T, T ^H , or Q siloxy units, provided that at least one siloxy unit includes SiH.

The component (A) and the component (B) are reacted by a hydrosilylation reaction. The hydrosilylation reaction is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably performed by adding a hydrosilylation catalyst.
The hydrosilylation catalyst is not particularly limited and may be appropriately selected depending on the intended purpose. For example, platinum, rhodium, ruthenium, palladium, osmium, iridium metal, organometallic compounds thereof, or combinations thereof Etc.
The content of the hydrosilylation catalyst is preferably from 0.1 ppm to 1,000 ppm, more preferably from 1 ppm to 100 ppm, based on the mass of the component (A) and the component (B).

The hydrosilylation reaction can be performed without dilution or in the presence of a solvent, but is preferably performed in the presence of a solvent.
Examples of the solvent include alcohols (eg, methanol, ethanol, isopropanol, butanol, or n-propanol), ketones (eg, acetone, methyl ethyl ketone, or methyl isobutyl ketone); aromatic hydrocarbons (eg, benzene, toluene, Or xylene); aliphatic hydrocarbons (eg, heptane, hexane, or octane); glycol ethers (eg, propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, or ethylene) Glycol n-butyl ether), halogenated hydrocarbons (eg, dichloromethane, 1,1,1-trichloroethane, or methylene chloride, chloroform), dimethyl Rusuruhokishido, dimethylformamide, acetonitrile, tetrahydrofuran, gasoline, mineral spirits, or naphtha, and the like. These may be used individually by 1 type and may use 2 or more types together.

The amount of the component (A) and the component (B) used in the hydrosilylation reaction is not particularly limited and can be appropriately adjusted according to the purpose. The total unsaturated group in the component (A) , Expressed as a molar ratio with the SiH content of the component (B). It is preferable to use a polyether unsaturated group amount of 20 mol% or less, preferably 10 mol% or less of the polyether unsaturated group amount, relative to the SiH molar amount of the organohydrogensiloxane. preferable.
The hydrosilylation reaction is not particularly limited, and can be performed in any known batch method, semi-continuous method, or continuous method, and for example, can be performed in a continuous method using a plug flow reactor.

Examples of commercially available products of the polyether-modified siloxane compound include 71ADDITIVE, 74ADDITIVE, 57ADDITIVE, 8029ADDITIVE, 8054ADDITIVE, 8211ADDITIVE, 8019ADDITIVE, 8526ADDITIVE, FZ-2123, and FZ-2191 (all manufactured by TORAY Dow Corning 44; , TSF4441, TSF4445, TSF4446, TSF4450, TSF4452, TSF4460 (all manufactured by Momentive Performance Materials); Silface SAG002, Silface SAG003, Silface SAG005, Silface SAG503A, Silface SAG008, Silface SJM003 ( All manufactured by Nissin Chemical Industry Co., Ltd.); TEGO Wet KL245, TEGO Wet 250, TEGO Wet 260, TEGO Wet 265, TEGO Wet 270, TEGO Wet 280 (all manufactured by Evonik); BYK-345, BYK-347, BYK-348, BYK-375, BYK-377 (all are manufactured by Big Chemie Japan), and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, TEGO Wet 270 (manufactured by Evonik) and Silface SAG503A (manufactured by Nissin Chemical Industry Co., Ltd.) are preferable.

  As the surfactant, in addition to the polyether-modified siloxane compound, a fluorine-based surfactant, a silicone-based surfactant, an acetylene glycol or an acetylene alcohol-based surfactant may be used in combination.

  The content of the surfactant is preferably 0.001% by mass to 5% by mass and more preferably 0.5% by mass to 3% by mass with respect to the total amount of the ink. When the content is 0.001% by mass or more and 5% by mass or less, the ink does not easily wet the ink repellent layer of the nozzle plate of the ink head, the ejection failure due to the ink nozzle adhesion is prevented, and the ejection stability is improved. The effect is obtained.

The ink of the present invention contains, as another aspect, a colorant, at least one organic solvent selected from compounds represented by the following structural formulas (1) to (5), resin particles, and water, Contains other components as needed.
[Structural formula (1)]
[Structural formula (2)]
[Structural formula (3)]
[Structural formula (4)]
[Structural formula (5)]

  The coloring material, the resin particles, the organic solvent other than the compounds represented by the structural formulas (1) to (5), and water are the same as those of the ink of the present invention described above.

<Other ingredients>
The other components are not particularly limited and may be appropriately selected as necessary. For example, a foam suppressor (antifoaming agent), a pH adjuster, an antiseptic / antifungal agent, a chelating reagent, a rust preventive agent, Antioxidants, ultraviolet absorbers, oxygen absorbers, light stabilizers and the like can be mentioned.

-Antifoaming agent (antifoaming agent)-
The antifoaming agent (antifoaming agent) is used to suppress foaming by adding a small amount to the ink. Here, the foaming means that the ink becomes a thin film and encloses air. Properties such as the surface tension and viscosity of the ink are involved in the generation of the bubbles. That is, a liquid having a high surface tension such as water is difficult to foam because a force that attempts to make the surface area of the liquid as small as possible works. On the other hand, highly viscous and highly permeable inks tend to foam due to their low surface tension, and bubbles generated by the viscosity of the solution are easily maintained and are difficult to defoam.

Usually, the foam suppressor destroys the foam by locally lowering the surface tension of the foam film to destroy the foam or by interspersing the foam suppressor with a foam suppressor insoluble in the foam liquid. When a very strong polyether-modified siloxane compound that reduces surface tension as a surfactant is used in the ink, the surface tension of the foam film is locally reduced even if the foam suppressor using the former mechanism is used. It is not usually used because it cannot. For this reason, an antifoaming agent that is insoluble in the latter foaming liquid is used. In this case, the stability of the ink is lowered by the antifoaming agent that is insoluble in the solution.
On the other hand, the foam suppressor represented by the following general formula (A) is not as strong as the polyether-modified siloxane compound in reducing the surface tension, but has high compatibility with the polyether-modified siloxane compound. For this reason, when the foam suppressor is efficiently incorporated into the foam film, the surface of the foam film is locally unbalanced due to the difference in surface tension between the polyether-modified siloxane compound and the foam suppressor, and the foam is destroyed. Conceivable.

  Therefore, a compound represented by the following general formula (A) is used as the foam suppressor.

<General formula (A)>
In the general formula (A), _{R 4} and _{R 5} are independently an alkyl group having 3-6 carbon atoms, _{R 6} and _{R 7} are alkyl having 1-2 carbon atoms independently N is an integer of 1-6.

  Examples of the compound represented by the general formula (A) include 2,4,7,9-tetramethyldecane-4,7-diol, 2,5,8,11-tetramethyldodecane-5,8- Examples include diols. Among these, 2,5,8,11-tetramethyldodecane-5,8-diol is preferable from the viewpoint of high antifoaming effect and high compatibility with ink.

  The content of the foam suppressor is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 5% by mass or less with respect to the total amount of the ink. When the content of the foam suppressor is 0.01% by mass or more, an effect of suppressing foam can be obtained. On the other hand, when the content of the antifoaming agent is 10% by mass or less, good antifoaming properties are obtained, and ink physical properties such as viscosity and particle size are appropriate.

-PH adjuster-
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 to 11 without adversely affecting the ink to be prepared, and can be appropriately selected according to the purpose. For example, alcohol amines , Alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like. When the pH is less than 7 or more than 11, the amount of the ink-jet head or ink supply unit that melts out increases, and problems such as ink deterioration, leakage, and ejection failure may occur.
Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide and quaternary ammonium hydroxide.
Examples of the phosphonium hydroxide include quaternary phosphonium hydroxide.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

-Antiseptic and fungicide-
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol and the like.

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

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

-Antioxidant-
Examples of the antioxidant include phenolic antioxidants (including hindered phenolic antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.

<Ink production method>
The ink of the present invention is produced by dispersing or dissolving the colorant, the organic solvent, the resin particles, the surfactant, and, if necessary, the other components in water and stirring and mixing them. The stirring and mixing can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, a stirrer using a stirring blade, a magnetic stirrer, a high-speed disperser, or the like.

-Ink physical properties-
There is no restriction | limiting in particular as a physical property of the said ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s to 25 mPa · s, and more preferably 6 mPa · s to 20 mPa · s. By setting the ink viscosity to 5 mPa · s or more, the effect of improving the printing density and the character quality can be obtained. On the other hand, by suppressing the ink viscosity to 25 mPa · s or less, it is possible to ensure dischargeability.
Here, the said viscosity can be measured at 25 degreeC, for example using a viscometer (RE-550L, Toki Sangyo Co., Ltd. make).

The ink of the present invention is suitably used for either inkjet recording or spray coating.
The ink for ink-jet recording is an ink-jet head that deforms a diaphragm that forms a wall surface of the ink flow path by using a piezoelectric element as a pressure generating means for pressurizing the ink in the ink flow path. A so-called piezo type that discharges ink droplets by changing the temperature (see Japanese Patent Application Laid-Open No. 2-51734), or a so-called thermal type that generates bubbles by heating ink in an ink flow path using a heating resistor. (Refer to Japanese Patent Laid-Open No. 61-59911), the diaphragm and the electrode forming the wall surface of the ink flow path are arranged to face each other, and the diaphragm is deformed by the electrostatic force generated between the diaphragm and the electrode. Thus, any ink jet head such as an electrostatic type that discharges ink droplets by changing the volume of the ink flow path (see JP-A-6-71882) can be used. It can be satisfactorily used in the printer for mounting.

(Ink container)
The ink container of the present invention contains the ink of the present invention in a container, and further includes other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.

(Image forming method and image forming apparatus)
The image forming method of the present invention includes an ink flying step, and further includes other steps appropriately selected as necessary.
The image forming apparatus of the present invention has ink flying means, and further has other means appropriately selected as necessary.

  The image forming method of the present invention can be suitably carried out by the image forming apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

<Ink flying process and ink flying means>
The ink flying step is a step of forming an image on a recording medium by applying a stimulus (energy) to the ink of the present invention and causing the ink to fly.
The ink flying means is means for applying a stimulus (energy) to the ink of the present invention and causing the ink to fly to form an image on a recording medium. The ink flying means is not particularly limited, and examples thereof include various nozzles for ejecting ink.

  The stimulus (energy) can be generated by, for example, the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose. Heat (temperature), pressure, vibration, For example, light. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.

  Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, a heating resistor. Examples include a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal conversion element such as a shape memory alloy actuator that uses a metal phase change caused by a temperature change, and an electrostatic actuator that uses an electrostatic force.

  There is no particular limitation on the mode of the ink flying, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the thermal energy corresponding to the recording signal is output to the ink in the recording head. For example, using a thermal head or the like, generating bubbles in the ink by the thermal energy, and ejecting and ejecting the ink as droplets from the nozzle holes of the recording head by the pressure of the bubbles, etc. Is mentioned. When the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element is bent, and the pressure chamber For example, there is a method in which the volume is reduced and the ink is ejected and ejected as droplets from the nozzle holes of the recording head.

<Other processes and other means>
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a drying process, a control process, etc. are mentioned.
There is no restriction | limiting in particular as said other means, According to the objective, it can select suitably, For example, a drying means, a control means, etc. are mentioned.

-Drying process and drying means-
The drying step is a step of heating and drying a recording medium on which an image is recorded with the ink, and is performed by a drying unit.
There is no restriction | limiting in particular in the said drying, According to the objective, it can select suitably, For example, it can carry out with an infrared dryer, a microwave dryer, a roll heater, a drum heater, or warm air. In order to smooth the image forming surface and fix the image, there may be provided a fixing step in which heat fixing is performed by heating to 100 ° C. or more and 150 ° C. or less by a heating means.
By providing the fixing step, the gloss and fixability of the recorded matter are improved. Here, as the heat fixing means, a roller having a heated mirror surface, a drum heater or the like is preferably used, and the mirror surface portion (smooth portion) of the roll heater or drum heater can be brought into contact with the image forming surface. Regarding the heating temperature, a fixing roller heated to 100 ° C. or higher and 150 ° C. or lower is preferable in view of image quality, safety, and economic efficiency.

-Control process and control means-
The control step is a step of controlling each of the steps, and is performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording method, such as a printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier complex machine, and a three-dimensional modeling apparatus.
In the present invention, the recording apparatus and the recording method are an apparatus capable of ejecting ink, various treatment liquids, and the like to a recording medium, and a method of performing recording using the apparatus. The recording medium means a medium on which ink or various processing liquids can be temporarily attached.
The recording apparatus can include not only a head portion that ejects ink but also means for feeding, transporting, and discharging a recording medium, and other devices called pre-processing devices and post-processing devices. .
The recording apparatus and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, a means for heating and drying the printing surface and the back surface of the recording medium. Although it does not specifically limit as a heating means and a drying means, For example, a warm air heater and an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, what forms patterns, such as geometric patterns, and what forms a three-dimensional image are also included.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise specified.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, for example, a continuous paper wound up in a roll shape as a recording medium. Also included are continuous paper printers.
An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective view of the apparatus. FIG. 2 is an explanatory perspective view of the main tank. An image forming apparatus 400 as an example of a recording apparatus is a serial type image forming apparatus. A mechanism unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), yellow (Y) is packaged, for example, an aluminum laminate film It is formed by a member. The ink storage unit 411 is stored in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404. Thus, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and ink can be discharged from the discharge heads 434 to the recording medium.

The recording apparatus can include not only a portion that ejects ink but also a device called a pre-processing device or a post-processing device.
As one mode of the pretreatment device and the posttreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a pretreatment liquid and a posttreatment liquid are included. There is a mode in which a liquid container and a liquid discharge head are added, and a pretreatment liquid and a posttreatment liquid are discharged by an ink jet recording method.
As another aspect of the pretreatment apparatus and the posttreatment apparatus, there is an aspect in which, for example, a pretreatment apparatus or a posttreatment apparatus other than the ink jet recording method is provided by a blade coating method, a roll coating method, or a spray coating method.

  The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional stereoscopic image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

(Liquid discharge device)
The liquid ejection apparatus of the present invention is a liquid ejection apparatus comprising the ink of the present invention and a liquid ejection section having a nozzle for ejecting the ink,
The liquid ejection unit has a liquid chamber communicating with the nozzle, and a first supply port and a second supply port for allowing the ink to flow into or out of the liquid chamber;
The liquid ejecting apparatus includes a circulation unit that causes the ink flowing out from one of the first supply port and the second supply port to flow into the other supply port through a circulation path, and Other means are provided as necessary.

When the ink of the present invention is ejected by a conventional head, the ink in the vicinity of the meniscus is likely to form a film at the time of decap and may cause abnormal ejection such as bending or shaking when re-ejection. The effect of circulating the ink in the vicinity of the meniscus is obtained by the head it has, so it is possible to prevent film formation at the time of capping, improve ejection stability over a long period of time, and stably provide high-quality recording Is possible.
In the head having the circulation means, the ink is circulated, so that it is difficult to maintain the meniscus as compared with the conventional head, and there is a problem that meniscus overflow and bubble entrapment are likely to occur. However, by combining the ink of the present invention with the head having the above circulation means, the balance between the dynamic surface tension A and the static surface tension B in the ink can be optimized, and the ink which is difficult to wet the water repellent film of the nozzle plate. As a result, the meniscus can be maintained, and the meniscus can be prevented from overflowing and air bubbles can be prevented, and a high-quality image can be provided stably over a long period of time.

Here, FIG. 3 is a schematic diagram showing a configuration as an example of the liquid ejection apparatus (inkjet apparatus, image forming apparatus) of the present invention.
The liquid ejection apparatus 1 includes a nozzle 3 that ejects droplets of ink and the like, a head (liquid ejection unit, liquid ejection head) 2 having an ejection mechanism, and a liquid (first liquid, second liquid) in the head 2. A first ink supply path (first path) 100 for supplying liquid, and a second ink supply path (second liquid) for supplying liquid (first liquid, second liquid) to the head 2. Path) 110 and a first liquid supply section 20 including an ink tank (first liquid storage section) 21 that supplies ink (first liquid) 22 to the head 2 via the first ink supply path 100. Are connected to the first ink supply path 100 and the second ink supply path 110 via the valve A (first switching valve 101) and the valve B (second switching valve 111), respectively, and the head Circulation route that bypasses 2 (third route 120, a deaeration device 121 (a deaeration device 121a + a vacuum generation device (pump) 121b) and a liquid circulation means (pump) 122 disposed on the circulation path 120, and the first ink supply path 100 or the second A cleaning liquid supply path (fourth path) 130 connected to the ink supply path 110 via the valve C (third switching valve 102), and a cleaning liquid 42 (second liquid) to the head via the cleaning liquid supply path 130. ) And a first ink supply path for flowing the liquid in the first ink supply path 100 or the second ink supply path 110 to the head. 100 or a valve D (path opening / closing means 112) installed on the second ink supply path 110.

The head (liquid ejection unit) 2 includes a plurality of fine nozzles 3 that eject ink (first liquid) 22 on the tip surface, and a liquid chamber (not shown) that communicates with the nozzles and holds ink therein. I have. In addition, a first supply port 5 and a second supply port 6 for allowing ink or cleaning liquid to flow into or out of the liquid chamber are disposed at different portions of the head 2, respectively. The first supply port 5 is connected to one end of the first ink supply path 100, and the second supply port 6 is connected to one end of the second ink supply path 110.
Examples of a method (liquid ejection mechanism) for ejecting ink as droplets from the nozzle 3 include a method in which ink is heated and pushed out, and a method in which ink is pushed out by applying a voltage to a piezoelectric element disposed inside the head and deforming it. It is done.
Printing can be performed by ejecting ink onto a printing target (not shown). Examples of the print target include sheet-like materials such as paper.

One end of the first ink supply path (first path) 100 is connected to the first supply port 5 of the head, and the other end communicates with the ink 22 in the ink tank 21, and the three flow paths r1 and r2 are connected. , R3.
The cleaning liquid supply path (fourth path) 130 includes a flow path r4 having one end connected to the valve C and the other end communicating with the cleaning liquid 42 in the cleaning liquid tank 41.

The valve A (first switching valve 101), the valve B (second switching valve 111), and the valve C (third switching valve 102) are connected in communication with three paths, respectively. It has a function of conducting (communication) any two of them simultaneously. That is, the valve A is disposed in the middle of the first ink supply path 100 and is connected to one end of the circulation path 120. The valve B is disposed in the middle of the second ink supply path 110 and is connected to the other end of the circulation path 120. The valve C is disposed in the middle of the first ink supply path 100 closer to the ink tank 21 than the valve A, and is connected to one end (downstream end) of the cleaning liquid supply path 130.
The valve D (path opening / closing means 112) is disposed in the middle of the second ink supply path 110 closer to the waste liquid tank 50 than the valve B, and opens and closes the second ink supply path 110 to communicate with the atmosphere. Has a function of connecting and disconnecting (blocking, connecting).
As a method of switching the connection pattern (opening / closing pattern) between paths by the valve A, the valve B, the valve C, and the valve D, there are a manual method, a pneumatic method, and an electromagnetic method. However, when these are controlled by a control circuit (not shown), an electromagnetic type is preferable.

Next, the ink tank 21 and its peripheral part (first liquid supply part 20) will be described.
The ink tank 21 is a container that stores ink discharged from the nozzles of the head 2.
A first pressurization device (first pressurization means) 23 and a decompression device (decompression means) 24 communicate with the gas phase at the upper part in the ink tank.
Also, one end (opening) of the first ink supply path 100 enters the ink tank and reaches the lower part thereof, and is arranged to communicate with the ink 22 inside the ink tank.
The first ink supply path 100 is connected from the ink tank 21 to the first supply port 5 through the valve C and the valve A.
The first pressurizing device 23 is a pneumatic pressurizing device that sends out compressed air, and is arbitrarily controlled to be driven and stopped in response to a control signal from a control circuit (not shown).
An example of the first pressurizing device 23 is a configuration in which a compressor and a solenoid valve that opens and closes a path for sending out compressed air generated by the compressor are combined.
When the first pressure device 23 is driven, the gas phase in the sealed ink tank is pressurized, and the ink is pushed out in the direction of the first ink supply path 100.

The decompression device 24 is a device that decompresses air, and is driven, stopped, and the amount of decompression is controlled by a control circuit (not shown). The decompression device 24 generates a pressure difference between the first liquid supply unit and the second ink supply path 110 to recover the ink (first liquid) from the head to the first liquid supply unit 20. 1 liquid recovery mechanism.
The decompression device 24 may be configured by combining a vacuum pump and an adjustment device that regulates the amount of decompression by limiting the flow rate of air flowing through a path connected to the vacuum pump.
When the decompression device 24 is driven to decompress the gas phase in the ink tank, the ink in the first ink supply path 100 is drawn back to the ink tank 21 side.

In the liquid ejecting apparatus 1, when the ink pressure in the head 2 is larger than the atmospheric pressure, ink leaks unintentionally from the nozzle 3. In order to prevent this, it is effective to drive the decompression device 24. By depressurizing the gas phase in the sealed ink tank, the ink in the ink tank is depressurized. Thereby, a negative pressure is supplied into the liquid chamber of the head through the first ink supply path 100, and the ink in the head can be decompressed. For this reason, the pressure of the ink in the head can be maintained at an appropriate negative pressure.
Further, by increasing the amount of pressure generated by the pressure reducing device, the ink in the head can be collected in the ink tank through the first ink supply path 100.

Next, the configuration of the cleaning liquid tank 41 and its peripheral part (second liquid supply part 40) will be described.
The cleaning liquid tank 41 is a sealed container that stores the cleaning liquid 42 for cleaning the head 2 and its peripheral paths 100 and 110. A second pressurizing device (second pressurizing means) 43 communicates with the gas phase at the upper part in the cleaning liquid tank 41.
Further, the end (opening) of the cleaning liquid supply path 130 enters the cleaning liquid tank and extends to the lower part thereof, and is arranged to communicate with the cleaning liquid inside the cleaning liquid tank.
The cleaning liquid supply path 130 is connected to the valve C from the cleaning liquid tank 41.
The internal configuration of the second pressure device 43 is the same as that of the first pressure device 23.
When the second pressurizing device 43 is driven, the gas phase in the cleaning liquid tank is pressurized, and the cleaning liquid is pushed out toward the cleaning liquid supply path 130.

Next, the configuration of the waste liquid tank 50 and its periphery will be described.
The waste liquid tank 50 is a container for discharging a part of the cleaning liquid 42 that has cleaned the liquid chamber of the head. The liquid discharged from the head to the second ink supply path 110 is received by the waste liquid tank 50.
The waste liquid in the waste liquid tank is not in contact with the end of the second ink supply path 110, and the end of the second ink supply path 110 on the waste liquid tank side is in contact with the atmosphere.
Thereby, when the pressure reducing device 24 on the ink tank side is driven, the air can be sucked into the head 2 from the second ink supply path 110.
The waste liquid tank 50 is used for cleaning the head peripheral path in a cleaning process described later.

Next, the circulation path 120 that circulates the liquid through the path avoiding the head will be described.
The circulation path 120 has one end connected to the valve A and the other end connected to the valve B. A deaerator 121a, a pump 122, and a filter 123 are disposed on the circulation channel.
The deaeration device 121a is a device that removes dissolved gas in the ink. The inside of the deaeration device is divided into an ink chamber 121a-1 and a gas chamber 121a-2. The ink chamber and the gas chamber are partitioned by a member 121a-3 that allows the gas to pass through without passing the liquid. When ink is flowed into the ink chamber 121a-1 and the gas chamber 121a-2 is depressurized, the gas dissolved in the ink in the ink chamber moves to the gas chamber via the gas-permeable member 121a-3, and passes through the ink. I can degas. A hollow fiber membrane is mentioned as a member which permeate | transmits gas without letting a liquid pass.
In addition, as a deaeration device, a material having a property of allowing ink to pass therethrough, for example, a hollow fiber bundle made of a Teflon (registered trademark) tube or a silicone tube is disposed in a deaeration chamber, and the periphery thereof is depressurized by a vacuum pump. It is also possible to use a gas treatment that separates and removes the gas dissolved in the ink. Furthermore, various other methods such as an ultrasonic vibration method and a centrifugal separation method can be adopted as the ink degassing method in the degassing device.

The filter 123 allows the ink flowing through the circulation path 120 to pass therethrough and removes dust, foreign matter, solid matter, and the like mixed in the ink. Examples of the filter material include fibrous materials such as glass fiber.
The pump 122 is means for circulating the ink in the circulation path 120 and the head 2 at a constant flow rate. Using a control circuit (not shown), the driving and stopping of the pump can be arbitrarily controlled.
The gas chamber 121a-2 of the deaerator is connected to the vacuum generator 121b through a tube 121c.
By depressurizing the gas chamber 121a-2 in the degassing device 121a by driving the vacuum generator 121b, degassing from the ink can be performed.
A vacuum pump etc. are mentioned as the vacuum generator 121b.
The vacuum generator can be arbitrarily controlled to be driven and stopped by a control circuit. Thereby, the deaeration and stop by a deaeration apparatus can be controlled arbitrarily.
The order in which the pump 122, the deaerator 121a, and the filter 123 are arranged in the circulation path may be in any order.

Next, a procedure for filling the circulation path 120 with ink will be described.
First, the valve A is operated and set so that the flow paths (r1, r2, r8) from the ink tank 21 to the deaeration device 121a are communicated. On the other hand, the flow path r3 is blocked by the valve A, and the flow path r4 is also blocked by the valve C. Further, the valve B is operated and set so that the pump 122 in the circulation path can communicate with the waste liquid tank 50 (atmosphere). The pump 122 is driven to move the ink from the ink tank 21 toward the waste liquid tank 50. In other words, the flow path r5 is blocked by the valve B to connect the flow paths r11 (flow paths r10, r9, r8) and the flow path r6, and the valve D is opened to connect the flow paths r6 and r7. The pump is driven until the circulation path 120 (r8, r9, r10, r11) from the valve A to the deaerator 121a, the pump 122, and the valve B is filled with ink. When the circulation path is filled with ink, the pump is stopped. As a result, ink is filled in the circulation path of the valve A to the deaerator 121 to the pump 122 to the filter 123 to the valve B.

Next, a method for filling the head with ink will be described.
By operating the valves A and C, the flow paths (r1, r2, r3) from the ink tank 21 to the first supply port 5 are set in a communicating state. The valve r is operated to keep the flow path r8 open. Further, the valve C is operated to block the flow path r4. Further, the valve B is operated so that the flow paths r5, r6, r11 are communicated, and the flow path is set from the second supply port 6 to the waste liquid tank. At this time, the valve D is operated to open the flow path r7.
As a result, the flow paths r1, r2, r3, the liquid chamber in the head, and the flow paths r5, r6, r7 are in communication. The circulation path 120 is also in communication with the first ink supply path 100 and the valve B.

Next, the inside of the ink tank 21 is pressurized using the first pressurizing device 23, and the ink 22 is moved into the head 2 through the first ink supply path 100. When the first ink supply path 100, the liquid chamber in the head, and the flow paths r1 to r3, r5, r6 from the second supply port 6 to the valve D are filled with ink, pressurization of the ink tank is stopped. To do. Next, the valve D is closed.
As a result, ink is filled in the ink tank 21 to the deaerator 121a to the pump 122 to the filter 123 to the valve B circulation path and the head.
By driving the head in this state, it is possible to eject ink droplets from the nozzles.
In addition, by driving the vacuum generator 121b while circulating the ink in the circulation path by the pump 122, deaeration from the ink using the deaerator 121a can be performed.
Since the ink is circulated and degassed in the circulation path using the pump as described above, the ink can be degassed. Further, as will be described later, the inside of the head can be cleaned by pressurizing the cleaning liquid with air pressure and pushing it out from the nozzle, so that it is possible to simultaneously satisfy two requirements that were difficult to achieve at the same time. .

  Next, ink circulation in the circulation type discharge head will be described. As shown in FIGS. 4 and 5, a supply port 71 that communicates with the common liquid chamber and a circulation port 81 that communicates with the circulation common liquid chamber 150 are formed at the end of the common liquid chamber member 220. The supply port 71 and the circulation port 81 are connected to a supply tank and a circulation tank for storing ink via tubes, respectively. Then, the ink stored in the supply tank is supplied to the individual liquid chamber 16 through the supply port 71, the common liquid chamber 10, the liquid introduction portion 8, and the fluid resistance portion 7.

Furthermore, while the ink in the individual liquid chamber 16 is ejected from the nozzle 4 by driving the piezoelectric member 12, part or all of the ink that remains in the individual liquid chamber 16 without being ejected is circulated in the fluid resistance portion 51. It is circulated to the circulation tank through the flow paths 52 and 53, the circulation common liquid chamber 150, and the circulation port 81.
The ink circulation can be performed not only when the circulation type discharge head is operated but also when the operation is stopped. By circulating at the time of operation stop, the ink in the individual liquid chamber is always refreshed, and aggregation and sedimentation of components contained in the ink can be suppressed, which is preferable.

In the liquid discharge head, a nozzle plate 201, a flow path plate 202, and a vibration plate member 203 as a wall surface member are laminated and joined. The piezoelectric actuator 11 that displaces the diaphragm member 203, the common liquid chamber member 220, and a cover are provided.
The nozzle plate 201 has a plurality of nozzles 4 that eject ink.
The flow path plate 202 forms an individual liquid chamber 16 that communicates with the nozzle 4, a fluid resistance portion 7 that communicates with the individual liquid chamber 16, and a liquid introduction portion 8 that communicates with the fluid resistance portion 7. The flow path plate 202 is formed by laminating and joining a plurality of plate-like members 141 to 145 from the nozzle plate 201 side, and laminating and joining these plate-like members 141 to 145 and the vibration plate member 203. A member 140 is configured.

The diaphragm member 203 has a filter unit 9 as an opening through the liquid introduction unit 8 and the common liquid chamber 10 formed by the common liquid chamber member 220.
The diaphragm member 203 is a wall surface member that forms the wall surface of the individual liquid chamber 16 of the flow path plate 202. The diaphragm member 203 has a two-layer structure (not limited), and is formed of a first layer that forms a thin portion and a second layer that forms a thick portion from the flow path plate 202 side. A deformable vibration region 30 is formed in a portion corresponding to the chamber 16.

  The plate-like member 141 constituting the flow path plate 2 is formed with a through groove part (meaning a groove-shaped through hole) constituting the individual liquid chamber 16, a fluid resistance part 51, and a through groove part constituting the circulation flow path 52. Has been.

Similarly, the plate-like member 142 is formed with a through groove portion constituting the individual liquid chamber 16 and a through groove portion constituting the circulation channel 52.
Similarly, the plate-like member 143 is formed with a through groove portion constituting the individual liquid chamber 16 and a through groove portion having the nozzle arrangement direction constituting the circulation channel 53 as a longitudinal direction.
Similarly, the plate-like member 144 has a through-groove portion constituting the individual liquid chamber 16, a through-groove portion constituting the fluid resistance portion 7, a through-groove portion constituting the liquid introduction portion 8, and a nozzle arrangement direction constituting the circulation flow path 53. A through groove portion is formed in the longitudinal direction.
Similarly, the plate-like member 145 includes a through groove portion that constitutes the individual liquid chamber 16, a through groove portion that becomes the longitudinal direction of the nozzle that constitutes the liquid introduction portion 8, and a circulation channel. A through groove portion having a longitudinal direction in the nozzle arrangement direction constituting 53 is formed.

The vibration plate member 203 is formed with a vibration region 30, a filter portion 9, and a through groove portion whose longitudinal direction is the nozzle arrangement direction constituting the circulation flow channel 53.
In this way, by configuring the flow path member 140 by laminating and joining a plurality of plate-like members, a complicated flow path can be formed with a simple configuration.

  With the above configuration, the flow path member 140 including the flow path plate 202 and the vibration plate member 203 is provided with the fluid resistance portion 51, the circulation flow path 52, and the circulation along the surface direction of the flow path plate 202 leading to each individual liquid chamber 16. A circulation channel 53 in the thickness direction of the channel member 140 that communicates with the channel 52 is formed. The circulation channel 53 communicates with a circulation common liquid chamber 150 described later.

  On the other hand, the common liquid chamber member 220 is formed with a common liquid chamber 10 and a circulation common liquid chamber 150 to which ink is supplied from a supply / circulation mechanism.

As described above, the common liquid chamber member 220 is configured by the first common liquid chamber member 221 and the second common liquid chamber member 222, and the first common liquid chamber member 221 is joined to the diaphragm member 203 side of the flow path member 140. The second common liquid chamber member 222 is laminated and joined to the first common liquid chamber member 221.
Here, the first common liquid chamber member 221 forms a downstream common liquid chamber 10 </ b> A that is a part of the common liquid chamber 10 that communicates with the liquid introduction unit 8, and a circulation common liquid chamber 150 that communicates with the circulation channel 53. ing. The second common liquid chamber member 222 forms an upstream common liquid chamber 10 </ b> B that is the remaining part of the common liquid chamber 10.

At this time, the downstream common liquid chamber 10A, which is a part of the common liquid chamber 10, and the circulation common liquid chamber 150 are arranged side by side in a direction orthogonal to the nozzle arrangement direction, and the circulation common liquid chamber 150 is arranged in the common liquid chamber 10. It is arranged at the position projected inside.
Thereby, the dimension of the circulation common liquid chamber 150 is not restricted by the dimensions required for the flow path including the individual liquid chamber 16, the fluid resistance section 7, and the liquid introduction section 8 formed by the flow path member 140.
The circulation common liquid chamber 150 and a part of the common liquid chamber 10 are arranged side by side, and the circulation common liquid chamber 150 is arranged at a position projected into the common liquid chamber 10 so as to be orthogonal to the nozzle arrangement direction. The width of the head in the direction can be suppressed, and the enlargement of the head can be suppressed. The common liquid chamber member 220 forms a common liquid chamber 10 and a circulation common liquid chamber 150 to which ink is supplied from a head tank or an ink cartridge.

  On the other hand, on the opposite side of the diaphragm member 203 from the individual liquid chamber 16, the piezoelectric actuator 11 including an electromechanical transducer as a driving unit that deforms the vibration region 30 of the diaphragm member 203 is disposed.

Next, a method for ejecting ink (droplets) from the nozzles of the head will be described.
The valve A and the valve C are operated so that the first ink supply path 100 from the ink tank 21 to the first supply port 5 is communicated. Operate the valve B to connect the flow paths r5 and r6, set the flow path from the second supply port 6 to the waste liquid tank (atmosphere), and operate the valve D to open the flow path r7. set.
At this time, the liquid chamber in the head is filled with ink, and the first ink supply path 100 from the ink tank to the head is opened.

Next, the head is driven using a head drive circuit (not shown), and ink is ejected from the nozzles.
When ink is ejected and the ink in the liquid chamber in the head is consumed, the ink is supplied from the ink tank to the head by osmotic pressure.
Further, by driving the pressure reducing device 24 to adjust the amount of pressure reduction in the ink tank, the ink pressure in the head is maintained at an appropriate negative pressure through the gas phase in the ink tank and the first ink supply path 100. .

Here, a negative pressure amount for properly maintaining the ink pressure in the head will be described.
When the ink tank is installed at a position relatively higher than the head and the head is filled with ink, pressure is applied to the ink in the head according to Bernoulli's theorem.
Here, the pressure of the gas phase in the ink tank is P1. Further, the ink pressure of the nozzle portion in the head is set to P2. Further, the height of the bottom surface of the ink tank as viewed from the nozzle portion is h0.
At this time, the ink pressure P2 of the nozzle portion is given by the following equation.
P2 = P1 + ρ * h0 * g (Formula 1)
Here, in (Formula 1), ρ is the density of the ink, and g is the acceleration of gravity.

If the pressure P1 in the gas phase in the ink tank is equal to the atmospheric pressure, the ink pressure P2 in the nozzle portion is a pressure larger than the atmospheric pressure according to the equation 1. At this time, since the pressure of the air outside the nozzle is atmospheric pressure, the pressure P2 in the nozzle portion becomes higher than the air outside the nozzle, and a phenomenon occurs in which ink dripping from the nozzle portion to the outside occurs.
In order to prevent ink from dripping from the nozzle portion to the outside, the ink pressure P2 of the nozzle portion needs to be approximately the same as the atmospheric pressure.
In order to prevent ink from dripping from the nozzle portion to the outside, it is effective to make the pressure P1 of the gas phase in the ink tank smaller than the atmospheric pressure from the relationship of the above formula 1.
When the pressure of the gas in the gas phase in the ink tank when the ink pressure P2 of the nozzle portion is equal to the atmospheric pressure is P1 ′, P1 ′ is given by the following equation from the above equation 1.
P1 ′ = P0−ρ * h0 * g (Formula 2)
Here, in (Formula 2), P0 is atmospheric pressure.

When the ink is ejected from the head, the decompression device is driven so that the pressure in the gas phase of the ink tank is approximately the same as P1 ′ given by Equation 2.
Printing can be performed by relatively moving the print target and the head while discharging ink from the head.

Next, a method for circulating and degassing the ink in the circulation path 120 (circulation and degassing timing, ink flow direction and flow channel) will be described.
As an example, the liquid ejection apparatus 1 provides a deaeration method for deaeration while circulating ink (second liquid) in the circulation path 120 (third path).
In this deaeration method for deaeration while circulating, the valve A (first switching valve 101), the circulation path 120, the valve B (second switching valve 111), and the head 2 (liquid discharge part) are closed. In addition, the ink is circulated by the pump 122 (liquid circulation means) and the deaeration device 121a (deaeration) in a state where the ink is filled in the path (flow paths r3, r8, r9, r10, r11, r5, head). The feature is that the deaeration is performed from the ink using the means.
In other words, in this example, circulation and deaeration are performed in a state where ink is filled in the valve A to the first supply port 5 to the head 2 to the second supply port 6 to the valve B and the circulation path 120. .
First, the valve A, the deaerator 121a, the pump 122, the filter 123, the valve B, the second supply port 6, the head 2, the first supply port 5, and the ink in the closed path of the valve A are circulated by a pump. To do.
At this time, the valve A is set so that the flow paths r3 and r8 from the first supply port 5 to the deaeration device communicate with each other (the flow path r2 is shut off). The valve B is set so that the flow paths r10, r11, r5 from the pump to the second supply port 6 communicate with each other (the flow path r6 is blocked).

Next, while the pump 122 is driven to circulate the ink in the path, the ink is deaerated using a deaeration device. That is, the vacuum generator 121b is driven to depressurize the gas chamber 121a-2 inside the deaerator. Thus, the dissolved air in the ink flowing inside the liquid chamber 121a-1 of the deaerator is sucked to the vacuum generator through the deaerator and the ink is deaerated.
At this time, since the ink passes through the filter 123 in the circulation path, fine particles such as dust mixed in the ink can be removed.
Ink circulation and deaeration are performed for a predetermined time. After a predetermined time has elapsed since the start of circulation and deaeration, the vacuum generator 121b is stopped to stop the deaeration operation. Next, the pump is stopped to stop the ink circulation.
The direction in which the ink is circulated in the closed path by the pump 122 can be circulated and degassed by either clockwise or counterclockwise in FIG.

In the present invention, a “liquid ejection head” is a functional component that ejects and ejects liquid from a nozzle.
The liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head. However, the liquid has a viscosity of 30 mPa · s or less at room temperature, normal pressure, or by heating and cooling. It is preferable. More specifically, solvents such as water and organic solvents, coloring materials such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium , Edible materials such as natural pigments, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and electronic circuit resist patterns. It can be used in applications such as forming liquids and three-dimensional modeling material liquids.

As energy generation sources for discharging liquid, piezoelectric actuators (laminated piezoelectric elements and thin film piezoelectric elements), thermal actuators using electrothermal transducers such as heating resistors, electrostatic actuators consisting of a diaphragm and counter electrode are used. To be included.
A “liquid ejection unit” is a unit in which functional parts and mechanisms are integrated with a liquid ejection head, and is an assembly of parts related to liquid ejection. For example, the “liquid discharge unit” includes a combination of at least one of a supply / circulation mechanism, a carriage, a maintenance / recovery mechanism, and a main scanning movement mechanism with a liquid discharge head.

Here, the term “integrated” refers to, for example, a liquid discharge head, a functional component, and a mechanism that are fixed to each other by fastening, adhesion, engagement, etc., and one that is held movably with respect to the other. Including. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.
For example, there is a liquid discharge unit in which a liquid discharge head and a supply / circulation mechanism are integrated. Also, there are some in which a liquid discharge head and a supply / circulation mechanism are integrated by being connected to each other by a tube or the like. Here, a unit including a filter may be added between the supply / circulation mechanism of these liquid discharge units and the liquid discharge head.

In addition, there is a liquid discharge unit in which a liquid discharge head and a carriage are integrated.
In addition, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably on a guide member that constitutes a part of the scanning movement mechanism.
Also, there is a liquid discharge unit in which a cap member that is a part of the maintenance / recovery mechanism is fixed to a carriage to which the liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. .
Some liquid discharge units have a liquid discharge head and a supply mechanism integrated by connecting a tube to a liquid discharge head to which a supply / circulation mechanism or a flow path component is attached. The liquid in the liquid storage unit is supplied to the liquid discharge head via this tube.
The main scanning movement mechanism includes a guide member alone. The supply mechanism includes a single tube and a single loading unit.

  In the present invention, the “apparatus for ejecting liquid” is an apparatus that includes a liquid ejection head or a liquid ejection unit and that drives the liquid ejection head to eject liquid. The apparatus for ejecting liquid includes not only an apparatus capable of ejecting liquid to an object to which liquid can adhere, but also an apparatus for ejecting liquid toward the air or liquid.

This “apparatus for discharging liquid” may include means for feeding, transporting, and discharging a liquid to which liquid can adhere, as well as a pre-processing apparatus and a post-processing apparatus.
For example, as a “liquid ejecting device”, an image forming device that forms an image on paper by ejecting ink, a powder is formed in layers to form a three-dimensional model (three-dimensional model) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto the powder layer.
Further, the “apparatus for ejecting liquid” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “applicable liquid” means that the liquid can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic boards and piezoelectric elements, media such as powder layers (powder layers), organ models, and test cells. Unless specifically limited, anything to which liquid adheres is included.

The material of the above-mentioned “material to which liquid can adhere” is not limited as long as liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics can be adhered even temporarily.
The “liquid” is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, and the viscosity becomes 30 mPa · s or less at room temperature, normal pressure, or by heating and cooling. Preferably there is. More specifically, solvents such as water and organic solvents, coloring materials such as dyes and pigments, functional compounds such as polymerizable compounds, resins and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium , Edible materials such as natural pigments, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and electronic circuit resist patterns. It can be used in applications such as forming liquids and three-dimensional modeling material liquids.

In addition, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can adhere move relatively, but is not limited thereto. Specific examples include a serial type apparatus that moves the liquid discharge head, a line type apparatus that does not move the liquid discharge head, and the like.
In addition to the “device for discharging liquid”, a processing liquid coating apparatus for discharging a processing liquid onto a sheet for applying a processing liquid to the surface of the sheet for the purpose of modifying the surface of the sheet, or a raw material There is an injection granulating apparatus or the like that granulates fine particles of a raw material by spraying a composition liquid in which a solution is dispersed in a solution through a nozzle.
In addition, the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling”, and the like in the terms of the present invention are all synonymous.

(Image formation)
The image formed article of the present invention is an image formed article having a recording medium and an image layer on the recording medium,
The image layer contains a color material, an organic solvent, and a resin,
The resin comprises a resin having a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and the dynamic surface tension A of the ink at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method is 34.0 mN / The dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are 10.0% ≦ [(A−B) / (A + B)] × 100. ≦ 19.0% is satisfied.
The image-formed product is capable of forming a high-quality image with suppressed beading, not only on plain paper but also on general-purpose printing paper, and has excellent image fixability, and various printing or image recording. It can be suitably used for various purposes as a prepared document.

<Recording medium>
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plain paper, glossy paper, special paper, cloth, film, OHP sheet, and general-purpose printing paper.
Among these, liquid absorption characteristics are within a certain range because images with excellent image quality (image density, saturation, beading, color bleed), high gloss, and excellent smear fixability can be recorded. Is a recording medium having a coating layer on at least one surface of a support, and the surface having the coating layer is measured with a dynamic scanning absorptiometer. net transfer amount to the recording medium of the water is preferably 2 mL / ^{m 2} or more 35 mL / ^{m 2} or less in the contact time 100 ms, and the amount of transferred onto the recording medium of pure water at the contacting time 400ms is 3 mL / ^{m 2} or more A recording medium of 40 mL / m ² or less is preferred.
Even with the ink described above, if the recording medium has too little transfer amount of pure water, beading (a phenomenon in which adjacent dots are attracted and the image feels jerky) and color bleeding (bleeding between colors) occur. If the recording medium has a transfer amount of pure water that is too large, the ink dot diameter after recording becomes smaller than the desired diameter, and the solid image may not be filled.
Here, the dynamic scanning absorptiometer (DSA, Kojipa Gakkai, Vol. 48, May 1994, pp. 88-92, Kuju Shigenori) has a very short time. It is a device that can measure accurately. In this dynamic scanning absorption meter, (i) the liquid absorption speed is read directly from the movement of the meniscus in the capillary, (ii) the sample is formed into a disk shape, and the liquid absorption head is scanned in a spiral shape in advance. The measurement is automated by a method in which the scanning speed is automatically changed according to the set pattern and the measurement is performed for the number of necessary points with one sample. A liquid supply head for a paper sample is connected to a capillary via a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, the transfer amount of pure water was measured using a dynamic scanning absorption meter (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.). The transfer amount at the contact time of 100 ms can be obtained by interpolation from the measured value of the transfer amount at the contact time adjacent to the contact time.
As the general-purpose printing paper having a liquid absorption characteristic within a certain range, commercially available products can be used. Examples of the commercially available products include POD gloss coat, OK top coat +, OK Kanto +, SA Kanto + (Oji Paper). Co., Ltd.), Super MI Dal, Aurora Coat, Space DX (Nippon Paper Industries Co., Ltd.), α Matte, Mu Coat (Hokuetsu Paper Co., Ltd.), Thunderbird Art, Thunderbird Super Art (Chuetsu Pulp Co., Ltd.), Pearl coat N (Mitsubishi Paper Co., Ltd.) etc. are mentioned.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Preparation Example 1)
-Preparation of surface modified black pigment dispersion (1)-
Black Pearls (registered trademark) 1000 (carbon black having a BET specific surface area of 343 m ² / g and DBPA 105 mL / 100 g) manufactured by Cabot Corporation, 100 mmol of sulfanilic acid, and 1 L of ion-exchange high-purity water under a room temperature environment, a Silverson mixer ( 6,000 rpm).
When the pH of the resulting slurry was higher than 4, 100 mmol of nitric acid was added. After 30 minutes, sodium nitrite (100 mmol) dissolved in a small amount of ion-exchanged high purity water was slowly added to the above mixture. Further, the mixture was heated to 60 ° C. with stirring and reacted for 1 hour.
Next, a modification comprising a pigment bound with at least one sulfanilic acid group or sulfanilic acid tetrabutylammonium salt after 30 minutes by adjusting the pH to 9 with a 10% by weight tetrabutylammonium hydroxide solution (methanol solution). A pigment dispersion was obtained.
Next, ultrafiltration using a dialysis membrane was performed using the obtained modified pigment dispersion containing a pigment bonded to at least one sulfanilic acid group or sulfanilic acid tetrabutylammonium salt and ion-exchange high purity water. Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The surface treatment level of the resulting modified pigment dispersion was 0.75 mmol / g, and the volume average particle size was 120 nm as measured by a particle size distribution measuring device (Nanotrack UPA-EX150, manufactured by Nikkiso Co., Ltd.). It was.

(Preparation Example 2)
-Preparation of surface modified black pigment dispersion (2)-
ProcessAll 4HV mixer (4 L), Black Pearls (registered trademark) 880 (carbon black having BET specific surface area 220 m ² / g and DBPA 105 mL / 100 g) manufactured by Cabot Corporation, ion exchange high purity water 1 L, and 4-aminobenzoic acid 1 mole of acid was added. The mixture was then mixed vigorously at 300 rpm while warming to 60 ° C. for 10 minutes. To this was added a 20 wt% aqueous sodium nitrite solution [1 molar equivalent based on 4-aminobenzoic acid] over 15 minutes. The mixture was stirred for 3 hours while heating to 60 ° C. The reaction product was taken out while being diluted with 750 mL of ion-exchange high purity water.
Next, the pigment is bound to at least one aminobenzoic acid group or aminobutyltetrabutylammonium salt after 30 minutes by adjusting the pH to 9 with a 10% by mass tetrabutylammonium hydroxide solution (methanol solution). A modified pigment dispersion was obtained.
Next, ultrafiltration using a dialysis membrane is performed using the obtained modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or aminobutyltetrabutylammonium salt and ion-exchanged high-purity water. It was. Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The surface treatment level of the obtained modified pigment dispersion was 0.5 mmol / g, and the volume average particle size was 104 nm as measured by a particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac UPA-EX150). It was.

(Preparation Example 3)
-Preparation of surface modified black pigment dispersion (3)-
ProcessAll 4HV mixer (4L), Black Pearls (registered trademark) 880 (carbon black having BET specific surface area 220 m ² / g and DBPA 105 mL / 100 g) manufactured by Cabot Corporation, 1 L of ion-exchange high-purity water, and 4-aminobenzoic acid 175 mmol was added. The mixture was then mixed vigorously at 300 rpm while warming to 60 ° C. for 10 minutes. To this was added a 20 wt% aqueous sodium nitrite solution [175 mmol equivalent based on 4-aminobenzoic acid] over 15 minutes. The mixture was stirred for 3 hours while heating to 60 ° C. The reaction product was taken out while being diluted with 750 mL of ion-exchange high purity water.
Next, a modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or aminobenzoic acid tetraethylammonium salt after 30 minutes by adjusting the pH to 9 with a 10 mass% tetraethylammonium hydroxide aqueous solution. Obtained.
Next, ultrafiltration using a dialysis membrane was performed using the obtained modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or aminoethyl tetrabenzoyl ammonium salt and ion-exchanged high-purity water. . Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The surface treatment level of the resulting modified pigment dispersion was 0.35 mmol / g, and the volume average particle size was 114 nm as measured with a particle size distribution measuring device (Nikki Co., Ltd., Nanotrac UPA-EX150). It was.

(Preparation Example 4)
-Preparation of surface modified black pigment dispersion (4)-
Self-dispersion type carbon black Aqua-Black 162 (manufactured by Tokai Carbon Co., Ltd., pigment solid content: 19.2% by mass) 1 kg of pigment dispersion was acidified with 0.1N HCl aqueous solution. Next, a modified pigment comprising a pigment bound to at least one carboxylic acid group or benzyltrimethylammonium carboxylate after 30 minutes by adjusting the pH to 9 with a 40% by weight benzyltrimethylammonium hydroxide solution (methanol solution) A dispersion was obtained.
Next, ultrafiltration using a dialysis membrane was performed using the obtained modified pigment dispersion containing a pigment bound to at least one carboxylic acid group or benzyltrimethylammonium carboxylate and ion-exchanged high purity water. Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
About the obtained modified pigment dispersion, the volume average particle diameter was measured by a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) and found to be 100 nm.

(Preparation Example 5)
-Preparation of surface modified black pigment dispersion (5)-
SENSIJET Black SDP2000 (manufactured by SENSIENT, pigment solid content 14.5% by mass) 1 kg of pigment dispersion was acidified with 0.1N HCl aqueous solution. Then, by adjusting the pH to 9 with a 10% by mass tetrabutylammonium hydroxide solution (methanol solution), after 30 minutes, at least one carboxylic acid group or carboxylic acid tetrabutylammonium salt, and sulfonic acid group or sulfonic acid tetra A modified pigment dispersion containing a pigment combined with a butylammonium salt was obtained.
Next, using the obtained modified pigment dispersion containing at least one carboxylic acid group or carboxylic acid tetrabutylammonium salt, and a pigment bonded to the sulfonic acid group or sulfonic acid tetrabutylammonium salt, and ion-exchanged high-purity water Ultrafiltration using a dialysis membrane was performed. Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
About the obtained modified pigment dispersion, the volume average particle diameter was measured by a particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac UPA-EX150), and it was 120 nm.

(Preparation Example 6)
-Preparation of surface modified magenta pigment dispersion (1)-
SENSIJET SMART Magenta 3122BA (Pigment Red 122 surface treatment dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT) 1 kg of the pigment dispersion was acidified with 0.1N HCl aqueous solution. Next, by adjusting the pH to 9 with a 10 mass% tetraethylammonium hydroxide aqueous solution, a modified pigment dispersion containing a pigment bonded with at least one aminobenzoic acid group or aminoethyltetraethylammonium salt after 30 minutes is obtained. It was.
Next, ultrafiltration using a dialysis membrane is performed using the obtained modified pigment dispersion containing a pigment combined with at least one aminobenzoic acid group or aminobenzoic acid tetraethylammonium salt, and ion-exchanged high-purity water, Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
About the obtained modified pigment dispersion, the volume average particle diameter was measured by a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150), and it was 104 nm.

(Preparation Example 7)
-Preparation of surface-modified cyan pigment dispersion (1)-
1 kg of SENSIJET SMART Cyan 3154BA (Pigment Blue 15: 4 surface treatment dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT) was acidified with 0.1N HCl aqueous solution. Subsequently, the pH is adjusted to 9 with a 40% by mass benzyltrimethylammonium hydroxide solution (methanol solution), so that the modified compound containing a pigment bonded with at least one aminobenzoic acid group or aminobenzylbenzoic acid benzyltrimethylammonium salt after 30 minutes. A quality pigment dispersion was obtained.
Next, ultrafiltration using a dialysis membrane is performed using the obtained modified pigment dispersion containing a pigment bound to at least one aminobenzoic acid group or aminobenzyl benzyltrimethylammonium salt and ion-exchanged high-purity water. It was. Furthermore, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
The volume-average particle size of the obtained minute modified pigment powder was measured by a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) and found to be 116 nm.

(Preparation Example 8)
-Preparation of surface modified yellow pigment dispersion (1)-
SENSIJET SMART Yellow 3074BA (Pigment Yellow 74 surface treatment dispersion, pigment solid content 14.5% by mass, manufactured by SENSIENT) 10% by adjusting the pH to 9 with a 10% tetrabutylammonium hydroxide solution (methanol solution), 30 A modified pigment dispersion was obtained comprising pigments bound with at least one aminobenzoic acid group or aminobenzoic acid tetrabutylammonium salt after a minute.
Next, ultrafiltration using a dialysis membrane is performed using the obtained modified pigment dispersion containing a pigment bonded to at least one aminobenzoic acid group or aminobutyltetrabutylammonium salt and ion-exchanged high-purity water. Further, ultrasonic dispersion was performed to obtain a modified pigment dispersion in which the pigment solid content was concentrated to 20% by mass.
With respect to the obtained modified pigment dispersion, the volume average particle diameter was measured by a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrac UPA-EX150) and found to be 145 nm.

(Preparation Example 9)
<Preparation of carbon black pigment-containing polymer particle dispersion>
-Preparation of polymer solution A-
After sufficiently replacing the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) and 0.4 g of mercaptoethanol were mixed and heated to 65 ° C.
Next, styrene 100.8 g, acrylic acid 25.2 g, lauryl methacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g, hydroxylethyl methacrylate 60.0 g, styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6) A mixed solution of 36.0 g, mercaptoethanol 3.6 g, azobismethylvaleronitrile 2.4 g, and methyl ethyl ketone 18 g was dropped into the flask over 2.5 hours. After dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added, and further aged for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask to obtain 800 g of a polymer solution A having a concentration of 50% by mass.

-Preparation of carbon black pigment-containing polymer particle dispersion-
28 g of the polymer solution A, C.I. I. 42 g of carbon black (manufactured by Degussa, FW100), 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of ion-exchanged water were sufficiently stirred and then kneaded using a roll mill. The obtained paste was put into 200 g of pure water and stirred sufficiently. Then, the ethyl ethyl ketone and water were distilled off using an evaporator, and this dispersion was removed from the polyvinylidene fluoride having an average pore size of 5.0 μm to remove coarse particles. A carbon black pigment-containing polymer particle dispersion having a pigment solid content of 15% by mass and a solid content concentration of 20% by mass was obtained by pressure filtration with a ride membrane filter.
The volume average particle size of the polymer particles in the obtained carbon black pigment-containing polymer particle dispersion was measured with a particle size distribution measuring device (Nikkiso Co., Ltd., Nanotrac UPA-EX150), and was 104 nm.

(Production Example 1)
<Preparation of resin emulsion 1>
As monomer (a1) 1.2 parts by mass of acrylic acid, as monomer (a2) 6 parts by mass of Silaace 210 (vinyltrimethoxysilane, manufactured by Chisso Corporation), as monomer (a3) 35.5 parts by mass of methyl methacrylate, acrylic 60.3 parts by mass of acid-2-ethylhexyl, 1.0 part by mass of acrylamide, 1.5 parts by mass of Aqualon KH-20 (Reactive emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier, and 53.1 ion-exchanged water The mixture of parts by mass was emulsified with a batch type homomixer to prepare a monomer pre-emulsion, which was put in a dropping tank.
When the number of particles of 0.5 μm or more is 5,000 / cm ³ or more, the measurement accuracy decreases, so that the number of particles of 0.5 μm or more is about 5,000 / cm ³ . A monomer pre-emulsion having a monomer concentration of about 60% is diluted with distilled water, and a monomer pre-emulsion number counting method is performed using an Accusizer manufactured by US PARTICS SIZING SYSTEMS for a diluted solution having a monomer concentration of about 0.002% by mass. The volume average particle diameter was determined to be 3.0 μm.

  A 2 L four-necked flask equipped with a reflux condenser, stirrer, thermometer, nitrogen inlet tube, and raw material inlet was used as a reaction vessel, and 89.4 parts by mass of ion-exchanged water was introduced into the reaction vessel, and nitrogen was introduced. While stirring, the liquid temperature was warmed to 60 ° C. Next, 0.5 part by mass of Aqualon KH-20 (Daiichi Kogyo Seiyaku Co., Ltd.) as an alkylphenol ether-based reactive emulsifier is added to the reaction vessel, and at the same time, 5% by mass ammonium persulfate (hereinafter referred to as “APS”). (Omitted) 6 parts by mass of an aqueous solution (0.3 parts by mass as ammonium persulfate) was added.

Ten minutes after adding the 5 mass% APS aqueous solution to the reaction vessel, the monomer pre-emulsion was continuously dropped over 5 hours from the dropping tank, and 6 parts by mass of the 5 mass% APS aqueous solution (excessive from another dropping tank). As ammonium sulfate, 0.3 part by mass) was dropped intermittently over 5 hours. During this time, the inside of the reaction vessel was kept at 70 ° C.
After completion of dropping, the mixture was kept at 70 ° C. for 3 hours for aging. Thereafter, cooling was started, the mixture was cooled to 50 ° C., ammonia water was added, and the mixture was filtered through a 180 mesh polyester filter cloth. The aggregate remaining on the filter cloth was dried at 150 ° C. for 20 minutes, and the amount of aggregation (mass%) was determined based on the amounts of the monomer, the emulsifier and the polymerization initiator, and found to be 0.1 mass%.
A part of the resin emulsion after filtration was weighed, dried at 150 ° C. for 20 minutes, and the solid content concentration was determined to be 39.5% by mass. The resin emulsion had a pH of 8 and a viscosity of 50 mPa · s.
Since the number of particles of 0.5 μm or more is about 5,000 particles / cm ³ or less, the measurement limit on the apparatus is limited, so that the resin emulsion after filtration is diluted to a solid content concentration of 0.002% by mass so as to be in such a range. Then, using Microtrac UPA (Leeds & Northrup), the cumulative 50% particle diameter (D ₅₀ ) by dynamic light scattering was measured and found to be 130 nm.
Separately, the resin emulsion after filtration was diluted to a solid content concentration of 0.002% by mass, and the diluted liquid was measured for the number of ultra coarse particles of 1.5 μm or more by the number counting method using an Accusizer manufactured by US PARTICLE SIZING SYSTEMS. did. When converted to a solid content concentration of 0.1% by mass, the number of super coarse particles of 1.5 μm or more in the resin emulsion was 1.0 × 10 ⁵ particles / cm ³ .
In addition, the glass transition temperature (henceforth "theoretical Tg") calculated | required from the monomer except vinyltrimethoxysilane was 5 degreeC.

(Production Example 2)
<Preparation of resin emulsion 2>
Resin emulsion 2 was produced in the same manner as in Production Example 1 except that the following composition was changed in Production Example 1.
[composition]
-Acrylic acid: 3.0 parts by mass-Butyl acrylate: 12.5 parts by mass-Acrylic acid-2-ethylhexyl: 20.0 parts by mass-Styrene: 22.0 parts by mass-Silaace 210 (vinyltrimethoxysilane, nitrogen) Co., Ltd.): 6 parts by mass Next, the obtained resin emulsion 2 was measured for a cumulative 50% particle diameter (D ₅₀ ) by a dynamic light scattering method, which was 100 nm. Moreover, the theoretical Tg calculated | required from the monomer except vinyltrimethoxysilane was 15 degreeC. Moreover, solid content concentration was 39.6 mass%.

(Production Example 3)
<Preparation of resin emulsion 3>
Resin emulsion 3 was produced in the same manner as in Production Example 1 except that the following composition was changed in Production Example 1.
[composition]
-Acrylic acid: 5.0 parts by mass-Acrylic acid-2-ethylhexyl: 22.0 parts by mass-Methacrylic acid-2-ethylhexyl: 6.0 parts by mass-Cyclohexyl methacrylate: 5.0 parts by mass-Styrene: 22. 0 part by mass-Sila Ace 210 (vinyltrimethoxysilane, manufactured by Chisso Corporation): 6 parts by mass Next, the obtained resin emulsion 3 was measured for a cumulative 50% particle diameter (D ₅₀ ) by a dynamic light scattering method. However, it was 80 nm. Moreover, the theoretical Tg calculated | required from the monomer except vinyltrimethoxysilane was 30 degreeC. Moreover, solid content concentration was 39.4 mass%.

(Production Example 4)
<Preparation of resin emulsion 4>
A resin emulsion 4 was produced in the same manner as in Production Example 1 except that the following composition was changed in Production Example 1.
[composition]
-Methacrylic acid: 3.0 parts by mass-Butyl acrylate: 25.0 parts by mass-Acrylamide: 1.0 parts by mass-Styrene: 29.0 parts by mass-Silaace 210 (vinyltrimethoxysilane, manufactured by Chisso Corporation): 6 parts by mass Next, with respect to the obtained resin emulsion 4, when the cumulative 50% particle diameter (D ₅₀ ) was measured by a dynamic light scattering method, it was 80 nm. Moreover, the theoretical Tg calculated | required from the monomer except vinyltrimethoxysilane was 45 degreeC. Moreover, solid content concentration was 39.5 mass%.

(Production Example 5)
<Preparation of resin emulsion 5>
Resin emulsion 5 was produced in the same manner as in Production Example 1 except that the following composition was changed in Production Example 1.
[composition]
-Methacrylic acid: 6.0 parts by mass-Ethyl acrylate: 20.0 parts by mass-Methyl methacrylate: 16.0 parts by mass-Acrylamide: 1.0 parts by mass-Styrene: 20.0 parts by mass-Silaace 210 (vinyl) Trimethoxysilane (manufactured by Chisso Corporation): 6 parts by mass Next, with respect to the obtained resin emulsion 5, the cumulative 50% particle diameter (D ₅₀ ) measured by the dynamic light scattering method was 90 nm. Moreover, the theoretical Tg calculated | required from the monomer except vinyltrimethoxysilane was 70 degreeC. Moreover, solid content concentration was 39.7 mass%.

Example 1
<Preparation of ink>
In a container equipped with a stirrer, 20.00 parts by mass of 3-n-butoxy-N, N-dimethylpropanamide of the structural formula (1), 25.00 parts by mass of 1,2-propanediol, 2,2,4- 2.00 parts by weight of trimethyl-1,3-pentanediol, 1.00 parts by weight of a polyether-modified siloxane compound of the structural formula (VII), and 2,4,7,9-tetramethyldecane-4,7-diol 0 50 parts by mass were added and stirred for 30 minutes to make it uniform.
Next, 0.05 parts by mass of an antifungal agent (Proxel GXL, manufactured by Avicia), 0.20 parts by mass of 2-amino-2-ethyl-1,3-propanediol, surface-modified black pigment dispersion of Preparation Example 1 37.50 parts by mass of body 1 and pure water were added and stirred for 60 minutes to make the ink uniform. Further, 6.25 parts by mass of the resin emulsion 1 of Production Example 1 was added to make the whole 100 parts by mass and stirred for 30 minutes to obtain an ink.
The obtained ink was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore diameter of 1.2 μm to remove coarse particles and dust, whereby the ink of Example 1 was produced.

(Example 2)
In a container equipped with a stirrer, 40.00 parts by mass of 3-ethyl-3-hydroxymethyloxetane of the structural formula (4), 2.00 parts by mass of 2,2,4-trimethyl-1,3-pentanediol, structural formula 2.00 parts by mass of a polyether-modified siloxane compound of (IX) and 0.50 parts by mass of 2,4,7,9-tetramethyldecane-4,7-diol were added and stirred for 30 minutes to be uniform.
Next, 0.05 parts by mass of an antifungal agent (Proxel GXL, manufactured by Avicia), 0.20 parts by mass of 2-amino-2-ethyl-1,3-propanediol, surface-modified black pigment dispersion of Preparation Example 1 37.50 parts by mass of body 1 and pure water were added, and the mixture was stirred for 60 minutes to be uniform.
Further, 6.25 parts by mass of the resin emulsion 2 of Production Example 2 was added to make the whole 100 parts by mass and stirred for 30 minutes to obtain an ink.
The obtained ink was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore diameter of 1.2 μm to remove coarse particles and dust, and thus an ink of Example 2 was produced.

(Examples 3 to 15 and Comparative Examples 1 to 8)
In the same manner as in Example 1 or Example 2, the organic solvents, surfactants, and antifoaming agents shown in Tables 1 to 5 below were mixed and stirred. Next, the fungicide, the pH adjuster, the color material (pigment dispersion), and the resin emulsion were mixed and stirred to make the ink uniform.
The obtained ink was subjected to pressure filtration with a polyvinylidene fluoride membrane filter having an average pore diameter of 1.2 μm to remove coarse particles and dust, and inks of Examples 3 to 15 and Comparative Examples 1 to 8 were produced. .

The organic solvents used in Examples 1 to 15 and Comparative Examples 1 to 8 are collectively shown in Table A below.

Abbreviations in Tables 1 to 5 represent the following meanings.
* SENSIJET SMART Magenta 3122BA: manufactured by SENSIENT (surface-treated pigment dispersion, aminobenzoic acid Na salt)
* SENSIJET SMART Cyan 3154BA: manufactured by SENSIENT (surface-treated pigment dispersion, aminobenzoic acid Na salt)
* SENSIJET SMART Yellow 3074BA: manufactured by SENSIENT (surface-treated pigment dispersion, aminobenzoic acid Na salt)
* SENSIJET Black SDP2000: manufactured by SENSIENT (surface-treated pigment dispersion, carboxylic acid Na salt, sulfonic acid Na salt)
* Takelac W-6110: Polycarbonate polyurethane resin emulsion (Mitsui Chemicals, Inc., effective solid content 33.9% by mass, viscosity 455 mPa · s at 25 ° C.)
* Vinyl Blanc 700: Vinyl chloride acrylic resin emulsion (manufactured by Nissin Chemical Industry Co., Ltd., effective solid content 30.0% by mass, viscosity 100 mPa · s at 25 ° C., glass transition temperature (Tg) 70 ° C.)
* An organic solvent represented by the following structural formula (1) (3-n-butoxy-N, N-dimethylpropanamide)

[Structural formula (1), SP value: 9.03]
* An organic solvent (3-ethyl-3-hydroxymethyloxetane) represented by the following structural formula (4)

[Structural formula (4), SP value: 11.3]

* A polyether-modified siloxane compound represented by the following structural formula (VII)

[Structural Formula (VII)]
* A polyether-modified siloxane compound represented by the following structural formula (IX)

[Structural Formula (IX)]
* A polyether-modified siloxane compound represented by the following structural formula (X)

[Structural Formula (X)]

* TEGO Wet270: Polyether-modified siloxane compound (Evonik, active ingredient 100% by mass)
The “TEGO Wet270” is a polyether-modified siloxane compound having a structure represented by the general formula (III).
* Silface SAG503A: polyether-modified siloxane compound (manufactured by Nissin Chemical Industry Co., Ltd., 100% by mass of active ingredient)
The “Silface SAG503A” is a polyether-modified siloxane compound having a structure represented by the general formula (V).
* Unidyne DSN403N: Polyoxyethylene perfluoroalkyl ether (Daikin Industries, Ltd., active ingredient 100% by mass)
* Zonyl FS-300: polyoxyethylene perfluoroalkyl ether (manufactured by DuPont, 40 mass% active ingredient)
* Surfinol 104E: Acetylene glycol compound (manufactured by Nissin Chemical Industry Co., Ltd., 100% by mass of active ingredient)
* Softanol EP-7025: higher alcohol ethoxylate compound (manufactured by Nippon Shokubai Co., Ltd., 100% by mass of active ingredient)
* Proxel GXL: Antifungal agent based on 1,2-benzisothiazolin-3-one (Avicia, 20 mass% active ingredient, containing dipropylene glycol)

  Next, the ink physical properties of the inks of Examples 1 to 15 and Comparative Examples 1 to 8 were measured as follows. The results are shown in Table 6.

<Viscosity measurement>
The viscosity of each ink was measured at 25 ° C. using a viscometer (RE-550L, manufactured by Toki Sangyo Co., Ltd.).

<PH measurement>
The pH of each ink was measured at 25 ° C. using a pH meter (HM-30R type, manufactured by TOA-DKK).

<Dynamic surface tension measurement>
The dynamic surface tension of each ink was measured at 25 ° C. using SITA_DynoTester (manufactured by SITA) as the dynamic surface tension at the surface lifetime of 15 msec according to the maximum bubble pressure method.

<Static surface tension>
The static surface tension of each ink was measured at 25 ° C. using an automatic surface tension meter (DY-300, manufactured by Kyowa Interface Science Co., Ltd.).

-Image formation-
Using the image forming apparatus (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) under the environmental conditions adjusted to 23 ° C. ± 0.5 ° C. and 50 ± 5% RH, the piezo element The driving voltage was varied, and the recording medium was set such that the same amount of ink adhered to OK Top Coat manufactured by Oji Paper Co., Ltd. + (Basis weight 104.7 g / m ² ).

Next, with respect to Examples 1 to 15 and Comparative Examples 1 to 8, image density, beading resistance, ejection stability-1, ejection stability-2, fixing property-I, and fixing property are as follows. -II was evaluated. The results are shown in Tables 7 and 8.
Moreover, about Examples 1-15, the discharge stability-3 and the discharge stability-4 were evaluated as follows. The results are shown in Table 9.

<Image density>
A chart with 64 point characters “black square: ■” created by Word 2000 (manufactured by Microsoft) is printed on MyPaper (manufactured by Ricoh Co., Ltd.) as a recording medium, and the “black square” portion of the printing surface is spectral density. The color was measured with a meter (X-Rite 939, manufactured by X-Rite Co., Ltd.) and judged according to the following evaluation criteria. The printing mode used was a driver attached to the printer, in which the "plain paper-standard fast" mode was changed to "no color correction" from the user setting for plain paper. In addition, evaluation C or more is a range with no practical problem.
〔Evaluation criteria〕
A: Black: 1.25 or more, Yellow: 0.8 or more, Magenta: 1.00 or more, Cyan: 1.05 or more B: Black: 1.20 or more and less than 1.25, Yellow: 0.75 or more Less than 8, Magenta: 0.95 or more and less than 1.00, Cyan: 1.00 or more and less than 1.05 C: Black: 1.15 or more and less than 1.20, Yellow: 0.70 or more and less than 0.75, Magenta: 0.90 or more and less than 0.95, Cyan: 0.95 or more and less than 1.00 D: Black: less than 1.15, Yellow: less than 0.70, Magenta: less than 0.90, Cyan less than 0.95

<Beading resistance>
The recording medium was changed to OK Top Coat manufactured by Oji Paper Co., Ltd. (basis weight 104.7 g / m ² ), and the printing mode was changed to “no gloss correction” in the “Glossy paper-clean” mode with the driver attached to the printer. Using the mode, a solid image was printed in the same manner as the image density, and density unevenness (beading) of the solid image was visually observed, and judged according to the following evaluation criteria. In addition, evaluation C or more is a range with no practical problem.
[Evaluation criteria]
A: Not at all B: Slightly present C: Significantly D: Vigorous * A black solid image is very difficult to see by visual observation, and was magnified 40 times with an optical microscope.

<Discharge stability-1: intermittent discharge evaluation>
200 charts were continuously printed on MyPaper (manufactured by Ricoh Co., Ltd.) to fill a 5% area of A4 size paper per color created with Word 2000 (manufactured by Microsoft) with a solid image. The evaluation was based on the following criteria. The print mode used was a driver attached to the printer, in which the “plain paper-standard fast” mode was changed to “no color correction” from the user settings for plain paper. In addition, evaluation B or more is a range which is satisfactory practically.
[Evaluation criteria]
A: No discharge disturbance B: Some discharge disturbance C: Discharge disturbance or no discharge

<Discharge stability-2: Nozzle plate ink repellent time>
In an environment adjusted to a temperature of 23 ° C. ± 0.5 ° C. and a relative humidity of 50% ± 5%, 50 g of each ink is put into a 50 mL beaker and used in an image forming apparatus (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.). Take out the nozzle plate of the head that is picked up and pinch it with tweezers, soak it in ink at a speed of 315 mm / min, and measure the ink repellent time (ink draw time) from the ink repellent layer of the nozzle plate when taken out at the same speed. The evaluation was based on the following criteria. The ink-repellent layer of the nozzle plate is OPTOOL DSX manufactured by Daikin Industries, Ltd. In addition, evaluation C or more is a range with no practical problem.
[Evaluation criteria]
A: Ink repellent time is less than 10 seconds B: Ink repellent time is from 10 seconds to less than 30 seconds C: Ink repellent time is from 30 seconds to less than 60 seconds D: Ink repellent time is 60 seconds or more Since the plate is easily wetted with ink, it is easy to remove the nozzle in continuous discharge evaluation.

<Discharge stability-3: Discharge stability using a circulating head>
A liquid discharge apparatus incorporating the circulation type liquid discharge mechanism shown in FIGS. 3 to 5 (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) under environmental conditions adjusted to 23 ± 0.5 ° C. and 50 ± 5% RH. Using a modified machine, the drive voltage of the piezo element was varied so that the amount of ink discharged was equalized, and the same amount of ink was applied to the recording medium.
Next, 1,000 printing charts having a printing area of 5% were printed. Immediately after printing 1,000 sheets and after 24 hours from the end of printing, solid images, halftone images, and nozzle check patterns are printed on industrial inkjet paper (Made by Mitsubishi Paper Industries, SWORD iJET 4.3 gloss) five by five. In addition, the discharge uniformity and nozzle clogging were evaluated by visually observing the uniformity of images and the presence or absence of nozzle omission. The printing conditions were one-pass printing at a recording density of 100% duty and 600 × 300 dpi. Evaluation criteria are shown below. During this evaluation, the ink was always circulated regardless of the operation / pause of the circulation type discharge head. In addition, evaluation B or more is a range which is satisfactory practically.
[Evaluation criteria]
A: Discharge is not disturbed and nozzle is not clogged B: Discharge is slightly disturbed but nozzle is not clogged C: Discharge is greatly disturbed and nozzle is clogged

<Discharge stability-4: Discharge stability using a normal head>
Under the environmental conditions adjusted to 23 ± 0.5 ° C. and 50 ± 5% RH, using a liquid ejection device (IPSiO GXe-5500, manufactured by Ricoh Co., Ltd.) The drive voltage was varied so that the same amount of ink was applied to the recording medium.
Next, 1,000 printing charts having a printing area of 5% were printed. Immediately after printing 1,000 sheets and after 24 hours from the end of printing, solid images, halftone images, and nozzle check patterns are printed on industrial inkjet paper (Made by Mitsubishi Paper Industries, SWORD iJET 4.3 gloss) five by five. In addition, the discharge uniformity and nozzle clogging were evaluated by visually observing the uniformity of images and the presence or absence of nozzle omission. The printing conditions were one-pass printing at a recording density of 100% duty and 600 × 300 dpi. Evaluation criteria are shown below. During this evaluation, the ink was always circulated regardless of the operation / pause of the circulation type discharge head. In addition, evaluation B or more is a range which is satisfactory practically.
[Evaluation criteria]
A: Discharge is not disturbed and nozzle is not clogged B: Discharge is slightly disturbed but nozzle is not clogged C: Discharge is greatly disturbed and nozzle is clogged

<Fixability-I>
Changed the recording medium to Oji Paper Co., Ltd. OK Top Coat + (basis weight 104.7 g / m ² ), and changed the print mode to “Glossy Paper-Fast” mode with “No Color Correction” with the driver attached to the printer. Mode, a solid image is printed in the same manner as the image density, and is dried for 30 seconds with a natural convection dryer with an internal temperature set to 100 ° C., and the solid image is subjected to a friction tester (trade name: Crock Meter, Inc. Rub 20 reciprocations with a white paper OK top coat + set on Toyo Seiki Seisakusho, and measure the stain density on the white paper side rubbed with a spectral densitometer (X-Rite 939, manufactured by X-Rite Co., Ltd.). Judged. The stain density was a value excluding the background density of the recording medium. In addition, evaluation C or more is a range with no practical problem.
[Evaluation criteria]
A: Less than 0.1 B: 0.1 or more and less than 0.3 C: 0.3 or more and less than 0.5 D: 0.5 or more

<Fixability-II>
Changed the recording medium to Oji Paper Co., Ltd. OK Top Coat + (basis weight 104.7 g / m ² ), and changed the print mode to “Glossy Paper-Fast” mode with “No Color Correction” with the driver attached to the printer. Mode, a solid image is printed in the same manner as the image density, dried for 10 seconds with a natural convection dryer with an internal temperature set to 100 ° C., and the solid image and white paper OK top coat + are superimposed and 5 kg / cm A load of ² was applied and left in a 50% RH environment at 25 ° C. for 2 hours. After standing, the superimposed solid image and the white paper were peeled off, and the area transferred to the white paper side was visually observed and judged according to the following criteria. In addition, evaluation C or more is a range with no practical problem.
[Evaluation criteria]
A: No transfer B: Small dot image transferred C: Slight image transferred D: Image transferred

Aspects of the present invention are as follows, for example.
<1> An ink containing a coloring material, an organic solvent, resin particles, and water,
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and has a dynamic surface tension A of 34.0 mN at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method. / M or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are as follows: 10.0% ≦ [(A−B) / (A + B)] × The ink satisfies 100 ≦ 19.0%.
<2> The ink according to <1>, wherein the resin particles have a glass transition temperature (Tg) of 15 ° C. or higher.
<3> The dynamic surface tension A of the ink at 25 ° C. and a surface lifetime of 15 msec by the maximum bubble pressure method is 30.0 mN / m or less, and the dynamic surface tension A and the ink at 25 ° C. The ink according to any one of <1> to <2>, wherein the target surface tension B satisfies the following formula: 12.0% ≦ [(A−B) / (A + B)] × 100 ≦ 17.0% It is.
<4> The ink according to any one of <1> to <3>, wherein the static surface tension B at 25 ° C. of the ink is 20.0 mN / m or more and 30.0 mN / m or less.
<5> The organic solvent having a solubility parameter of 8.96 or more and less than 11.8 is at least one selected from compounds represented by the following general formula (I) and the following general formula (II) <1 > To <4>.
[General Formula (I)]
However, in said general formula (I), R 'shows a C4-C6 alkyl group.
[General Formula (II)]
In the general formula (II), R ″ represents an alkyl group having 1 to 2 carbon atoms.
<6> The ink according to any one of <1> to <5>, wherein the content of the organic solvent having a solubility parameter of 8.96 or more and less than 11.8 is 10% by mass or more based on the total amount of the ink. It is.
<7> Any one of <1> to <6>, wherein the content of the organic solvent having the solubility parameter of 8.96 or more and less than 11.8 is 20% by mass or more and 60% by mass or less with respect to the total amount of the ink. Ink.
<8> The ink according to any one of <1> to <7>, wherein the organic solvent does not contain a polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C. and a relative humidity of 80%.
<9> The ink according to any one of <1> to <8>, further including a polyether-modified siloxane compound as a surfactant.
<10> The ink according to <9>, wherein the polyether-modified siloxane compound is at least one selected from compounds represented by the following general formulas (III) to (VI).
[General Formula (III)]
However, in said general formula (III), m shows the integer of 0-23 and n shows the integer of 1-10. a represents an integer of 1 to 23, and b represents an integer of 0 to 23. R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (IV)]
However, in said general formula (IV), m shows the integer of 1-8, c and d show the integer of 1-10. R ₂ and R ₃ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (V)]
However, the general formula (V), e represents an integer from 1 to 8, _{R 4} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (VI)]
However, in said general formula (VI), f shows the integer of 1-8. R ₅ represents a polyether group represented by the following general formula (a).
[General Formula (a)]
However, in said general formula (a), g shows the integer of 0-23, h shows the integer of 0-23, g and h do not become 0 simultaneously. R ₆ represents either a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
<11> The ink according to any one of <9> to <10>, wherein the content of the polyether-modified siloxane compound is 0.001% by mass to 5% by mass.
<12> The ink according to any one of <1> to <11>, wherein the color material is a water-dispersible pigment.
<13> The ink according to <12>, wherein the water-dispersible pigment has a hydrophilic functional group on a surface, and the hydrophilic functional group is a quaternary ammonium salt.
<14> The ink according to <13>, wherein the water-dispersible pigment is a modified pigment modified with at least one of a geminal bisphosphonic acid group and a geminal bisphosphonate group.
<15> The ink according to any one of <12> to <14>, wherein the water-dispersible pigment is at least one selected from a black pigment, a cyan pigment, a magenta pigment, and a yellow pigment.
<16> The ink according to any one of <1> to <15>, wherein the ink is any one of inkjet recording and spray coating.
<17> An ink container comprising the ink according to any one of <1> to <16> in a container.
<18> Ink that records an image by applying the ink according to any one of <1> to <16> with at least one kind of stimulus selected from heat, pressure, vibration, and light and flying the ink. An image forming method including a flying step.
<19> Ink that records an image by applying the ink according to any one of <1> to <16> with at least one kind of stimulus selected from heat, pressure, vibration, and light and flying the ink. An image forming apparatus having a flying unit.
<20> An image formed article having a recording medium and an image layer on the recording medium,
The image layer contains a color material, an organic solvent, and a resin,
The resin comprises a resin having a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and the dynamic surface tension A of the ink at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method is 34.0 mN / The dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are 10.0% ≦ [(A−B) / (A + B)] × 100. An image formed product satisfying ≦ 19.0%.
<21> A liquid ejection apparatus comprising: the ink according to any one of <1> to <16>; and a liquid ejection unit having a nozzle that ejects the ink.
The liquid ejection unit has a liquid chamber communicating with the nozzle, and a first supply port and a second supply port for allowing the ink to flow into or out of the liquid chamber;
The liquid ejecting apparatus includes a circulation unit that causes the ink flowing out from one of the first supply port and the second supply port to flow into the other supply port through a circulation path. It is a liquid discharge apparatus.
<22> An ink containing a coloring material, an organic solvent, resin particles, and water,
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
An ink comprising at least one selected from compounds represented by the following structural formulas (1) to (5) as the organic solvent.
[Structural formula (1)]
[Structural formula (2)]
[Structural formula (3)]
[Structural formula (4)]
[Structural formula (5)]

  The ink according to any one of <1> to <16> and <22>, the ink container according to <17>, the image forming method according to <18>, and the image according to <19>. According to the forming apparatus, the image formed product described in <20>, and the liquid discharge apparatus described in <21>, the above-described problems can be solved and the object of the present invention can be achieved.

JP 2012-207202 A JP 2014-94998 A

Claims (20)

An ink containing a coloring material, an organic solvent, resin particles, and water,
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and has a dynamic surface tension A of 34.0 mN at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method. / M or less, and the dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are as follows: 10.0% ≦ [(A−B) / (A + B)] × An ink satisfying 100 ≦ 19.0%.   The ink according to claim 1, wherein the resin particles have a glass transition temperature (Tg) of 15 ° C. or higher.   The dynamic surface tension A at a surface life of 15 msec at 25 ° C. and the maximum bubble pressure method of the ink is 30.0 mN / m or less, and the dynamic surface tension A and the static surface tension of the ink at 25 ° C. The ink according to claim 1, wherein B satisfies the following formula: 12.0% ≦ [(A−B) / (A + B)] × 100 ≦ 17.0%.   The ink according to claim 1, wherein the ink has a static surface tension B at 25 ° C. of 20.0 mN / m or more and 30.0 mN / m or less. The organic solvent having a solubility parameter of 8.96 or more and less than 11.8 is at least one selected from the compounds represented by the following general formula (I) and the following general formula (II). The ink according to any one of the above.
[General Formula (I)]
However, in said general formula (I), R 'shows a C4-C6 alkyl group.
[General Formula (II)]
In the general formula (II), R ″ represents an alkyl group having 1 to 2 carbon atoms.   The ink according to any one of claims 1 to 5, wherein the organic solvent does not contain a polyhydric alcohol having an equilibrium water content of 30% or more at a temperature of 23 ° C and a relative humidity of 80%.   The ink according to any one of claims 1 to 6, further comprising a polyether-modified siloxane compound as a surfactant. The ink according to claim 7, wherein the polyether-modified siloxane compound is at least one selected from compounds represented by the following general formulas (III) to (VI).
[General Formula (III)]
However, in said general formula (III), m shows the integer of 0-23 and n shows the integer of 1-10. a represents an integer of 1 to 23, and b represents an integer of 0 to 23. R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (IV)]
However, in said general formula (IV), m shows the integer of 1-8, c and d show the integer of 1-10. R ₂ and R ₃ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (V)]
However, the general formula (V), e represents an integer from 1 to 8, _{R 4} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
[General Formula (VI)]
However, in said general formula (VI), f shows the integer of 1-8. R ₅ represents a polyether group represented by the following general formula (a).
[General Formula (a)]
However, in said general formula (a), g shows the integer of 0-23, h shows the integer of 0-23, g and h do not become 0 simultaneously. R ₆ represents either a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.   The ink according to any one of claims 7 to 8, wherein the content of the polyether-modified siloxane compound is 0.001 mass% or more and 5 mass% or less.   The ink according to claim 1, wherein the color material is a water-dispersible pigment.   The ink according to claim 10, wherein the water-dispersible pigment has a hydrophilic functional group on a surface, and the hydrophilic functional group is a quaternary ammonium salt.   The ink according to claim 11, wherein the water-dispersible pigment is a modified pigment modified with at least one of a geminal bisphosphonic acid group and a geminal bisphosphonic acid group.   The ink according to any one of claims 10 to 12, wherein the water-dispersible pigment is at least one selected from a black pigment, a cyan pigment, a magenta pigment, and a yellow pigment.   The ink according to any one of claims 1 to 13, which is one for inkjet recording and spray coating.   An ink container comprising the ink according to claim 1 contained in a container.   An ink flying step of applying an ink according to any one of claims 1 to 14 with at least one kind of stimulus selected from heat, pressure, vibration, and light and causing the ink to fly to record an image. An image forming method.   It has an ink flying means which records the image by applying the ink according to any one of claims 1 to 14 with at least one kind of stimulus selected from heat, pressure, vibration and light, and causing the ink to fly. An image forming apparatus. An image formed product having a recording medium and an image layer on the recording medium,
The image layer contains a color material, an organic solvent, and a resin,
The resin comprises a resin having a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
The organic solvent contains at least one organic solvent having a solubility parameter of 8.96 or more and less than 11.8, and the dynamic surface tension A of the ink at 25 ° C. and a surface life of 15 msec by the maximum bubble pressure method is 34.0 mN / The dynamic surface tension A and the static surface tension B of the ink at 25 ° C. are 10.0% ≦ [(A−B) / (A + B)] × 100. An image formed product satisfying ≦ 19.0%. A liquid ejection apparatus comprising: the ink according to any one of claims 1 to 14; and a liquid ejection unit having a nozzle that ejects the ink.
The liquid ejection unit has a liquid chamber communicating with the nozzle, and a first supply port and a second supply port for allowing the ink to flow into or out of the liquid chamber;
The liquid ejecting apparatus includes a circulation unit that causes the ink flowing out from one of the first supply port and the second supply port to flow into the other supply port through a circulation path. A liquid ejection device. An ink containing a coloring material, an organic solvent, resin particles, and water,
The resin particles are resin particles including a structural unit having a carboxyl group and a structural unit having an alkoxysilyl group,
An ink comprising at least one selected from compounds represented by the following structural formulas (1) to (5) as the organic solvent.
[Structural formula (1)]
[Structural formula (2)]
[Structural formula (3)]
[Structural formula (4)]
[Structural formula (5)]