JP2017002197A - Ink, ink cartridge, inkjet recording device, inkjet recording method and ink recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink providing high image density and excellent in storage stability and discharge recovery property.SOLUTION: An ink contains at least water, a water soluble solvent, a pigment and a polymer having a phosphonic acid group. The polymer is a copolymer having a diphosphonic acid group, at least a part of the diphosphonic acid group is tetraalkylammonium salt and the polymer has 2 or 3 specific structural units.SELECTED DRAWING: None

Description

  The present invention relates to an ink, an ink cartridge, an ink jet recording apparatus, an ink jet recording method, and an ink recorded matter.

  The inkjet recording method is popular because it has the advantage that the process is simpler than other recording methods, full color is easy, and even high-resolution images can be obtained even with a simple configuration. Have been doing. In this ink jet recording method, a small amount of ink is ejected by pressure generated using bubbles generated by heat, piezo or electrostatic, and the ink is attached to a recording medium such as paper and dried quickly (or recording). This is a method of forming an image by penetrating into a medium), and its application has been expanded to personal and industrial printers and printing.

In such an ink jet recording system, a water-based ink (dye ink) using a water-soluble dye as a colorant is mainly used. However, the dye ink has a defect that it is inferior in weather resistance and water resistance. For this reason, research on pigment inks that use water-insoluble pigments instead of water-soluble dyes is underway. However, the pigment ink is still inferior in color developability and ink storage stability to the dye ink.
Also, pigment ink is inferior in ejection stability compared to dye ink. For example, when water is evaporated at the tip of the ink head nozzle, the concentration of the water-soluble solvent is increased, the pigment and the ink composition are likely to precipitate, the ink is bent and the dots are missing, and the ink head nozzle is cleaned. An ejection performance recovery operation is required.
In addition, with the improvement of image quality improvement technology of OA printers, high image density is required even when plain paper is used as a recording medium in pigment ink. However, when the plain ink is used as the recording medium, the pigment ink has a problem that the pigment density on the paper surface is lowered by permeating into the paper and the image density is lowered.

In recent years, the demand for industrial applications has increased, and high-speed printing is desired. An ink jet printer equipped with a line head has been proposed along with such high-speed printing. In order to achieve high-speed printing, in order to increase the drying speed of the ink adhering to the recording medium, means for increasing the drying speed by adding a penetrant to the ink and allowing water to penetrate into the recording medium has been tried. In addition to this, there is a problem that the permeability of the pigment into the recording medium is increased and the image density is lowered.
In addition, when plain paper is used as a recording medium, there is a problem that immediately after printing, the surface of the plain paper is swollen by water as an ink solvent, the difference in elongation between the front and back is increased, and curling occurs. Since such a phenomenon disappears as the drying progresses, there was no problem in low-speed printing.
However, with the increase in printing speed, it is necessary to transport the recording medium without eliminating curling after printing, which may cause a paper jam problem. For curling, a means for increasing the content of the organic solvent in the ink is effective, but since the ink is more hydrophobic, it is difficult to ensure storage stability and ejection stability of the ink.

  In order to solve the above problems, for example, an ink-jet ink composition containing a liquid vehicle, a colorant, and a polymer having at least one functional group having a specific calcium index value has been proposed (see Patent Document 1). In this proposal, 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid is shown as a monomer constituting the polymer, and when the colorant comes into contact with the paper, the diphosphonic acid group of the polymer and the paper It is said that the printed image can be improved by making it unstable with the Ca salt therein. However, there is a problem that ink storage stability and ejection recovery properties are low.

  Further, an ink for ink jet recording containing water, a water-soluble organic solvent, a pigment, and a polymer containing a structural unit having a specific bisphosphonic acid group has been proposed (see Patent Document 2). In this proposal, 1-methacryloyloxyethane-1,1-diphosphonic acid is shown as a monomer constituting the previous polymer, and when the colorant comes into contact with the paper, the diphosphonic acid group of the polymer and the Ca in the paper It is said that the printed image can be improved by destabilizing with salt. Further, by using this polymer as a pigment dispersant, ink storage stability at 60 ° C. for one week is secured, but it is still insufficient in terms of storage stability. In addition, there is a problem that ink ejection characteristics from the nozzles become unstable when continuous printing is performed at a high speed, and there is a problem that ejection recoverability is low.

  Similarly, an ink for inkjet recording containing water, a water-soluble organic solvent, a pigment, and a polymer containing a structural unit having a specific bisphosphonic acid group has been proposed (see Patent Document 3). In this proposal, a specific monomer such as a salt of 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid and a hydrocarbon acrylate is used as a monomer constituting the polymer, and a high image density on plain paper. Ink storage stability is ensured, and by using this polymer as a pigment dispersant, ink storage stability at 60 ° C. for one week is ensured, but storage stability is still insufficient. Similarly, there is a problem that the ink ejection characteristics from the nozzles become unstable when continuous printing is performed at a high speed, and there is a problem that the ejection recoverability is low.

  In addition, an ink jet recording method has been proposed in which a receiving liquid containing a Ca salt is attached to paper, and ink containing a pigment having a phosphorus-containing group, a resin emulsion, and a surfactant is printed (see Patent Document 4). This proposal describes that bisphosphonic acid is preferable as the phosphorus-containing group, and describes that the Ca salt of the receiving solution reacts with the phosphorus-containing group and has an effect of improving feathering and fixing properties. Yes. However, in the proposed technique, a phosphonic acid group-containing polymer is not used as a dispersant and an additive for a pigment dispersion, but a phosphoric acid-bonded pigment is used, and an image when recorded on plain paper is used. The effect of increasing the concentration is not sufficient. In addition, in the case of this method, since it is necessary to chemically modify the pigment surface in advance, there is a problem that versatility in pigment selection is low.

Further, there has been proposed a water-based ink containing a colorant, water, a water-soluble organic solvent, a surfactant, and a chelating agent (see Patent Document 5). In this proposal, hydroxyethylidene diphosphonic acid or a salt thereof, which is a low molecular compound, is used as the chelating agent. The chelating agent is said to remove calcium and the like contained in a dispersion such as a pigment and improve discharge stability and storage stability. However, the proposal only describes a low molecular weight compound, hydroxyethylidene diphosphonic acid, and does not describe a polymer containing phosphonic acid, and improves the image density when recorded on a chelating agent and plain paper. It also does not describe the relationship with effects.
Therefore, it is desired to provide an ink for ink jet recording which can obtain a high image density even when recorded on plain paper and is excellent in storage stability and ejection recovery property even when the content of the water-soluble organic solvent is increased.

An object of the present invention is to solve the above-described problems and achieve the following objects.
That is, an object of the present invention is to provide an ink that can obtain a high image density and has excellent storage stability and ejection recovery property.

  The ink of the present invention as a means for solving the problems is an ink containing at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, and the polymer has a diphosphonic acid group. A copolymer, wherein at least a part of the diphosphonic acid group is a tetraalkylammonium salt, and the polymer is represented by the structural unit (1) represented by the general formula (1) and the general formula (2): It is an ink characterized by having at least the structural unit (2) represented.

(R ₁ in the general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in the general formula (2) represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.)

  According to the present invention, it is possible to provide an ink having a high image density and excellent storage stability and ejection recovery property.

It is the schematic plan view seen from the nozzle surface which shows an example (2 head type) of the recording head arrange | positioned at the inkjet recording device of this invention. It is the schematic plan view seen from the nozzle surface which shows another example (4 head type) of the recording head arrange | positioned at the inkjet recording device of this invention. FIG. 3 is a perspective explanatory view seen from the front side showing an example of an ink jet recording apparatus of the present invention having a maintenance / recovery device. It is a schematic block diagram explaining the whole structure of the mechanism part of the inkjet recording device shown in FIG. It is principal part plane explanatory drawing of the mechanism part of the inkjet recording device shown in FIG. FIG. 3 is a plan view of a principal part of a subsystem including a maintenance / recovery device in the ink jet recording apparatus of the present invention. It is a typical schematic block diagram of the subsystem shown in FIG. FIG. 7 is an explanatory diagram on the right side of the subsystem shown in FIG. 6. It is side surface explanatory drawing of the holding | maintenance raising / lowering mechanism part of a cap.

  Hereinafter, the present invention will be described in detail, but the present invention includes inks of the embodiments described below.

-Copolymer having diphosphonic acid group-
Hereinafter, the present invention will be described in detail and specifically.
The copolymer having a diphosphonic acid group in the present invention (hereinafter also referred to as polymer or copolymer polymer) is represented by the structural unit (1) represented by the general formula (1) and the general formula (2). It is a copolymer having at least the structural unit (2) represented.

  Apart from the above, the copolymer having a diphosphonic acid group in the present invention (hereinafter also referred to as a polymer or a copolymer polymer) includes the structural unit (1) represented by the general formula (1) and the general A copolymer having at least a structural unit (2) represented by the formula (2) and a structural unit (3) represented by the following general formula (3a), general formula (3b) or general formula (3c) is there.

(R ₃ in the general formula (3a) represents a hydrogen atom or a methyl group.)

(R ₄ in the general formula (3b) represents a hydrogen atom or a methyl group, and R ₅ and R ₆ each independently represents a methyl group or an ethyl group.)

(R ₇ in the general formula (3c) represents a hydrogen atom or a methyl group, and Y ₁ represents a methylene group or an ethylene group.)

Apart from the above, the copolymer having a diphosphonic acid group in the present invention (hereinafter also referred to as a polymer or a copolymer polymer) includes the structural unit (1) represented by the general formula (1) and the general It is a copolymer having at least the structural unit (2) represented by the formula (2) and the structural unit (4) represented by the following general formula (4a) or the general formula (4b).

(R ₈ in the general formula (4a) represents a hydrogen atom or a methyl group, R ₉ and R ₁₀ represent a methyl group or an ethyl group, and Y ₂ represents an alkylene group having 1 to 4 carbon atoms.)

(R ₁₁ in the general formula (4b) represents a hydrogen atom or a methyl group, and Y ₃ represents an alkylene group having 1 to ₃ carbon atoms.)

The M ⁺ tetraalkylammonium ion in the general formula (1) is an ammonium ion having 4 alkyl groups having 1 to 22 carbon atoms, such as a tetramethylammonium ion, a tetraethylammonium ion, a tetrapropylammonium ion, Examples thereof include tetrabutylammonium ion, tetraamylammonium ion, benzyltrimethylammonium ion, hydroxyethyltrimethylammonium ion, methyltrioctylammonium ion, and trimethylstearylammonium ion. In particular, when a tetraalkylammonium ion composed of an alkyl group having 1 to 5 carbon atoms is used, it is particularly preferable because an ink having a low viscosity and excellent storage stability can be provided.
Examples of tetraalkylammonium ions composed of alkyl groups having 1 to 5 carbon atoms include tetraethylammonium ion, tetrabutylammonium ion, methyltributylammonium ion, methyltriamylammonium ion, triethylmethylammonium ion, and ethyltrimethylammonium ion. Can be mentioned.
As M ⁺ , 2 or 3 are preferably tetraalkylammonium ions, and the rest are preferably hydrogen ions (protons).

Examples of the alkylene group having 2 to 18 carbon atoms represented by L in the general formula (2) include an ethylene group, a propylene group, a butylene group, a hexylene group, a nonylene group, a dodecylene group, and a stearylene group. it can. Moreover, Preferably it is a C2-C16 alkylene group, More preferably, it is a C2-C12 alkylene group.
The naphthyl group present at the terminal via L has excellent pigment adsorbing power due to π-π stacking with a pigment which is a coloring material in water-based ink (hereinafter also referred to as ink), so that the ink can be stored. Stability can be improved.

  The mass ratio of the structural unit (1) represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 20% by mass to 60% by mass with respect to the total amount of the polymer. % Is preferable, and 30% by mass to 50% by mass is more preferable. When the mass ratio is within a preferable range, it is advantageous in that a high image density is obtained when used for an ink jet recording ink, and dispersion stability, storage stability, and ejection stability are good. .

The copolymer having a diphosphonic acid group used in the present invention can be produced by the polymer production method of the present invention described below. Further, the copolymer containing the structural unit (1) represented by the general formula (1) and the structural unit (2) represented by the general formula (2) is not particularly limited, and can be widely used in various fields. Can do.
Furthermore, the structural unit (1) represented by the general formula (1), the structural unit (2) represented by the general formula (2), the general formula (3a), the general formula (3b), or the general formula (3c). The copolymer containing the structural unit (3) represented by the formula is not particularly limited and can be widely used in various fields.
The same applies to a copolymer containing the structural unit (4) represented by the general formula (4a) or the general formula (4b) together with the structural units (1) and (2) instead of the structural unit (3). It is.
For example, it can be suitably used as a pigment dispersant, pigment concentration improver, pigment binder resin, viscosity modifier and the like in ink jet recording ink.

<Method for producing polymer>
The polymer used in the present invention is a radical polymerization of a polymerizable raw material containing at least a monomer (1) represented by the following general formula (5) and a monomer (2) represented by the following general formula (6). Thereafter, the obtained polymer can be synthesized by further neutralizing with a tetraalkylammonium base.
In addition, the polymer used in the present invention includes at least a monomer (1) represented by the following general formula (5), a monomer (2) represented by the following general formula (6), and the following general formulas (7a) and (7b). ) Or (7c), after radical polymerization of a polymerizable material containing at least the monomer (3a), (3b) or (3c), the resulting polymer is further neutralized with a tetraalkylammonium base. Can be synthesized.
Furthermore, the polymer used in the present invention includes at least a monomer (1) represented by the following general formula (5), a monomer (2) represented by the following general formula (6), and the following general formula (8a) or ( After the radical polymerization of the polymerizable material containing at least the monomer (4a) or (4b) represented by 8b), the obtained polymer can be synthesized by further neutralizing with a tetraalkylammonium base. .

  Neutralization adjustment is a neutralization treatment that is performed in the case of further neutralization in addition to the tetraalkylammonium salt already neutralized in the monomer stage, and the same or different compound as the ammonium ion attached in the monomer stage. Neutralization adjustment can be performed. The total neutralization amount can adjust the amount of neutralization from 1 to 4 of the 4 acid groups in the general formula (1), but preferably 2 or 3 tetraalkylammonium ions per monomer molecule. .

  Specific examples of the monomer (1) represented by the general formula (5) include methacrylamidomethylene diphosphonic acid, acrylamide methylene diphosphonic acid and their disodium salt, trisodium salt, dipotassium salt, tripotassium salt, 2 tetramethyl ammonium salt, 3 tetramethyl ammonium salt, 2 tetraethyl ammonium salt, 3 tetraethyl ammonium salt, 2 tetrapropyl ammonium salt, 3 tetrapropyl ammonium salt, 2 tetrabutyl ammonium salt, 3 tetrabutyl ammonium salt and the like. Furthermore, the case where multiple types of tetraalkylammonium ions are mixed can be mentioned.

As a synthesis method of the monomer (1) represented by the general formula (5), a method of synthesizing by an esterification reaction of aminomethylene diphosphonic acid and (meth) acrylic acid chloride, and (meth) acrylamido methylene di A method of synthesizing from phosphonic acid tetramethyl ester by demethylation reaction may be mentioned.
In the former case, the aminomethylene diphosphonic acid is preferably neutralized in advance and then synthesized by an esterification reaction with acid chloride. After the reaction, the number of salts can be adjusted by reverse neutralization. In the latter case, the diphosphonic acid compound is obtained and then neutralized to adjust the number of salts.

In the general formula (6), the alkylene group having 2 to 18 carbon atoms represented by L is the same as in the general formula (2). The bonding position of the naphthyl group may be either α-position or β-position.
The monomer (2) represented by the general formula (6) can be synthesized and used as follows.
That is, as shown in the following reaction formulas (1) to (2), first, a naphthalenecarbonyl chloride (A-1) and an excess amount of a diol compound are subjected to a condensation reaction in the presence of an acid acceptor such as an amine or pyridine. To obtain naphthalenecarboxylic acid hydroxyalkyl ester (A-2). Subsequently, 2-methacryloyloxyethyl isocyanate (A-3) and the said (A-2) are made to react, and a monomer (2) can be obtained.

Examples of the monomer (3a) represented by the general formula (7a) include diacetone acrylamide and diacetone methacrylamide.
Examples of the monomer (3b) represented by the general formula (7b) include dimethyl (meth) acrylamide and diethyl (meth) acrylamide.
The monomer (3b) represented by the general formula (7b) can be used in combination with the monomer (3a) represented by the general formula (7a).
Examples of the monomer (3c) represented by the general formula (7c) include N- (hydroxymethyl) (meth) acrylamide and N- (2-hydroxyethyl) (meth) acrylamide.
The monomer (3c) represented by the general formula (7c) is used in combination with the monomer (3a) represented by the general formula (7a) and / or the monomer (7b) represented by the general formula (7b). can do.
Examples of the monomer (4a) represented by the general formula (8a) include N- [3- (dimethylamino) propyl] acrylamide, N- [3- (diethylamino) propyl] acrylamide, N- [2- (dimethylamino). ) Ethyl] acrylamide, N- [2- (diethylamino) ethyl] acrylamide, N- [2- (ethylmethylamino) ethyl] acrylamide, N- (dimethylaminomethyl) acrylamide, N- (diethylaminomethyl) acrylamide and the like. It is done.
Examples of the monomer (4b) represented by the general formula (8b) include trimethyl (meth) acryloyloxymethylammonium chloride, trimethyl-2- (meth) acryloyloxyethylammonium chloride, trimethyl-3- (meth) acryloyl. Examples thereof include oxypropylammonium chloride.
The monomer (4a) represented by the general formula (8a) and the monomer (4b) represented by the general formula (8b) may be used in combination.

The polymer containing the structural units (1) and (2) represented by the general formula (1) and the general formula (2) is obtained by using the monomer (1) and the monomer (2) obtained as described above. Polymerization is performed by a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method.
The polymer containing the structural units (1), (2) and (3) represented by the general formula (1), the general formula (2) and the general formula (3) is a monomer ( 1), monomer (2) and monomer (3) (= monomer (3a), (3b) or (3c)) are used for known bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. Polymerized by a polymerization method.
The polymer containing the structural units (1), (2) and (4) represented by the general formula (1), the general formula (2) and the general formula (4) is a monomer obtained as described above ( 1), a monomer (2) and a monomer (4) (= monomer (4a), (4b) or (4c)) are used for known bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc. Polymerized by a polymerization method.

Although not limited to these polymerization methods, a method using a radical polymerization initiator is preferable because the polymerization operation and molecular weight are easily adjusted, and a solution polymerization method in which polymerization is performed in a mixed solvent of an organic solvent and water is more preferable.
The operation for performing radical polymerization by the solution polymerization method is not particularly limited, but the monomer, initiator, chain transfer agent, and solvent may be charged all at once into the polymerization reaction vessel or continuously using a dropping funnel. May be supplied. Moreover, you may add an initiator during a polymerization reaction as needed.

As the solvent for the radical polymerization by the solution polymerization method, the monomer (1) is water-soluble and the monomer (2) is water-insoluble, so that a mixed solvent of water and a water-soluble organic solvent is preferable for mixing. As the water-soluble organic solvent, alcohol solvents such as methanol, ethanol, 2-methoxyethanol and 2-ethoxyethanol, ether solvents such as tetrahydrofuran, amide solvents such as N, N-dimethylformamide, and the like can be used. There is no particular limitation as long as it can be dissolved.
In addition to using a mixed solvent from the beginning, an aqueous solution of monomer (1) and an organic solvent solution of monomer (2) may be mixed during polymerization.
Making the solubility of the monomer (1) and the monomer (2) closer is important for improving the copolymerizability. In the present invention, the monomer (1) is converted into a tetraalkylammonium salt to form the monomer (2) Copolymers have been successfully synthesized by bringing the difference in solubility between the two. If a sodium salt similar to the monomer (1) is used, synthesis of the copolymer resin with the monomer (2) becomes difficult.
If attention is paid only to solubility, it is expected that the longer the alkyl group of tetraalkylammonium, the stronger the hydrophobicity and the better the copolymerization with monomer (2), but it is selected in balance with other properties. .
The monomer (3) may be dissolved in a mixed solvent from the beginning, or may be dissolved in an organic solvent simultaneously with the monomer (2).
Similarly, the monomer (4) may be dissolved in the mixed solvent from the beginning, or may be dissolved in the organic solvent simultaneously with the monomer (2).

There is no restriction | limiting in particular as a radical polymerization initiator, According to the objective, it can select suitably. For example, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, peroxyester, cyano-based azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobis (2 , 2′-isovaleronitrile), non-cyano dimethyl-2,2′-azobisisobutyrate, and the like. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable from the viewpoint of easy control of molecular weight and low decomposition temperature.
The content of the polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1% by mass to 20% by mass with respect to the total mass of the polymerizable monomer.

In order to adjust the molecular weight of the polymer, an appropriate amount of a chain transfer agent may be added. Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, nonyl mercaptan, 1-dodecanethiol, thioglycerol, and the like.
There is no restriction | limiting in particular in superposition | polymerization temperature, Although it can select suitably according to the objective, 50 to 150 degreeC is preferable and 60 to 100 degreeC is more preferable. The polymerization time is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 3 hours to 48 hours.

The resulting polymer is neutralized with a tetraalkylammonium base.
The neutralization treatment can be performed by neutralizing part or all of the phosphonic acid group of the polymer with a tetraalkylammonium base.
When neutralization has been completed in the monomer production process of the general formula (3), this neutralization process can be omitted, but usually 1 to 2 equivalents are neutralized in the monomer production process. The remaining acid groups are neutralized after polymerization.
The neutralization treatment of the tetraalkylammonium base can be performed in a state where the pigment and the polymer are mixed in the ink production process.

More specifically, an aqueous solution in which the monomer (1) of the general formula (5) is dissolved in a flask equipped with a stirrer, a thermometer, an inert gas (nitrogen or argon) introduction tube, and a condenser, the general formula The organic solvent solution in which the monomer (2) of (6) is dissolved, and the solution in which the polymerization initiator, the molecular weight modifier and the like are dissolved are batched or continuously stirred under an inert gas, and 60 ° C. to 150 ° C. It can synthesize | combine by making it react at this temperature and neutralizing with a tetraalkylammonium base.
Alternatively, an aqueous solution in which the monomer (1) of the general formula (5) is dissolved in a flask equipped with a stirrer, a thermometer, an inert gas (nitrogen or argon) introduction tube, and a condenser, the general formula (6) and An organic solvent solution in which the monomers (2) and (3) of the general formula (7a), (7b) or (7c) are dissolved, and a solution in which the polymerization initiator, the molecular weight modifier and the like are dissolved under an inert gas. It can synthesize | combine by carrying out neutralization with the tetraalkylammonium base, after making it stir batch or continuously and making it react at the temperature of 60 to 150 degreeC.
Alternatively, an aqueous solution in which the monomer (1) of the general formula (5) is dissolved in a flask equipped with a stirrer, a thermometer, an inert gas (nitrogen or argon) introduction tube, and a condenser, the general formula (6) and The organic solvent solution in which the monomers (2) and (4) of the general formula (8a) or (8b) are dissolved, and the solution in which the polymerization initiator, the molecular weight modifier and the like are dissolved are batched or continuously in an inert gas. Then, the mixture is stirred and reacted at a temperature of 60 ° C. to 150 ° C., and then neutralized with a tetraalkylammonium base.

The neutralization degree can be controlled by measuring the acid value of the resin in advance and performing neutralization treatment accordingly. The acid value is measured by dissolving or dispersing a weighed resin in water, a water-soluble organic solvent or a mixed solvent thereof, and neutralizing and titrating with a potassium hydroxide methanol solution with a specified concentration using thymolphthalein as an indicator.
As for the diphosphonic acid group of the polymer in the present invention, it is known that three of the four acid groups are neutralized when the color of thymolphthalein changes (pH = 8 to 9). Therefore, when the acid value is obtained using thymolphthalein as an indicator and neutralized by adding a base accordingly, a structure in which three acid groups are neutralized can be prepared.

  The ratio of the monomer (1) of the general formula (5) in the synthesis to the total monomers is preferably 20 to 60% by mass, and more preferably 30 to 50% by mass.

The resulting polymer has a molecular weight distribution depending on the degree of polymerization. Usually, the molecular weight can be easily measured by gel permeation chromatography (GPC), but the present polymer is a dissociative polymer and is difficult to measure due to adsorption to the GPC column.
Therefore, in the present invention, the viscosity when the polymer is a solution having a constant concentration is used as a substitute characteristic of molecular weight. The measuring method of a viscosity can be performed as follows. Using a viscometer (RE500L, manufactured by Toki Sangyo Co., Ltd.), it is adjusted to 50 or 100 rotations according to the viscosity of the sample.
The aqueous solution viscosity (10% by mass, 25 ° C.) of the polymer in the present invention is preferably 1.5 mPa · s to 4.0 mPa · s, and more preferably 1.7 mPa · s to 3.0 mPa · s. preferable.
If the aqueous solution viscosity of the polymer is 1.5 mPa · s or more, the image density is less likely to be lowered due to a decrease in calcium reactivity, and if it is 4.0 mPa · s or less, the pigment is caused by a decrease in dispersibility stability. Deterioration of storage stability of the dispersion and ink is less likely to occur.
When it is in the range of 1.7 mPa · s to 3.0 mPa · s, image density reduction and ink storage stability are more unlikely to occur. In addition, deterioration in ink storage stability may lead to a decrease in ejection recovery performance.

The molecular weight of the polymer in the present invention can be controlled to some extent by the polymerization temperature, the polymerization initiator amount, and the monomer concentration during the reaction.
Regarding the polymerization temperature, a low molecular weight polymer tends to be obtained when polymerized at a high temperature in a short time, and a high molecular weight polymer tends to be obtained when polymerized at a low temperature for a long time.
As for the content of the polymerization initiator, a larger amount tends to obtain a low molecular weight polymer, and a smaller amount tends to obtain a high molecular weight polymer.
As for the monomer concentration during the reaction, a higher concentration tends to yield a polymer having a higher molecular weight, and a lower concentration tends to yield a polymer having a lower molecular weight.
Further, as described above, the molecular weight of the copolymer in the present invention can be controlled by adjusting the amount of the chain transfer agent used. As is known, chain transfer agents receive radicals from the grown polymer chain and stop polymer elongation, but chain transfer agents that receive radicals can attack the monomer and start polymerization again, It also contributes to the adjustment of molecular weight distribution and the average molecular weight.

(ink)
The ink of the present invention contains water, a water-soluble organic solvent, a pigment and the polymer of the present invention, and further contains other components as necessary.

<Polymer in the present invention>
The ink of the present invention is characterized by containing the polymer of the present invention.
The structural unit represented by the general formula (1) is more water-soluble than the conventionally used diphosphonic acid structure alondronate methacrylamide or the like. Hydrophobic interaction with the pigment of the hydrophobic group becomes stronger, and the dispersion stability of the pigment increases.
Moreover, the structural unit derived from 1-methacryloxyethane-1,1-diphosphonic acid that has been conventionally used is not sufficient in storage stability and ejection recoverability because of a problem in hydrolysis resistance. On the other hand, the diphosphonic acid structure of the present invention is strong in hydrolysis resistance and is advantageous in storage stability and ejection stability.
As shown in the structural unit represented by the general formula (1), the diphosphonic acid group-containing structural unit is an acrylamide having a tetraalkylammonium salt, thereby increasing the hydrophobicity of the diphosphonic acid group-containing structural unit, Copolymerizability with the structural unit represented by the general formula (2) is improved. The structural unit represented by the general formula (2) has an excellent pigment adsorbing power due to π-π stacking with a pigment because a naphthyl group is present at the terminal via L.
That is, by using a copolymer resin containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2), only a high image density due to the polyvalent ion aggregation function of the diphosphonic acid group can be obtained. Therefore, it can exhibit excellent storage stability.
In addition, because of the excellent pigment adsorptivity, when water is evaporated at the tip of the ink head nozzle, the copolymer resin is less likely to be detached from the pigment even in an environment where the concentration of the water-soluble organic solvent is high. Precipitation due to dispersion instability can be prevented.
Furthermore, the hydrophobicity of the copolymer resin increases, so that the solubility of the copolymer resin in the vehicle can be maintained in an environment where the concentration of the water-soluble organic solvent is high, and the copolymer resin is deposited at the tip of the ink head nozzle. Can be prevented.
That is, by using a copolymer resin containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2), the pigment or the copolymer resin is deposited on the tip of the ink head nozzle. It is possible to suppress the ejection failure caused by this, and to reduce the ejection performance recovery operation such as head cleaning.
The structural unit (3) represented by the general formula (3a), the general formula (3b), or the general formula (3c) is represented by the general formula (1) because of its high affinity with the water-soluble solvent. And the structural unit represented by the general formula (2) and the structural unit represented by the general formula (3a), the general formula (3b) or the general formula (3c). By using this copolymer, the affinity of the copolymer resin with the water-soluble solvent can be increased, and the storage stability and ejection recovery property of the ink can be further improved.
Furthermore, the structural unit (4a) represented by the general formula (4a) belonging to the structural unit (4) has a tertiary amine structure and is basic, and is based on an acidic group and acid-base interaction existing on the pigment surface. It exerts a binding force and functions to compensate for the water-soluble solvent entering the ink vehicle and the hydrophobic interaction between the hydrophobic group and the pigment being weakened to reduce the pigment adsorbability of the resin. As a result, good dispersibility and storage stability can be improved even in an ink containing a water-soluble solvent. For example, many carbon black surfaces, which are black pigments, have a carboxyl group, and in that case, a tertiary amino group portion showing the basicity of the structural portion represented by the general formula (4a) and an acid-base interaction. Adsorbs strongly.
Further, the structural unit (4b) represented by the general formula (4b) belonging to the structural unit (4) has a quaternary ammonium base, and has a binding force due to an acid group interaction with an acidic group present on the pigment surface. Demonstrate. As a result, the water-soluble solvent enters the ink vehicle, and the hydrophobic interaction between the hydrophobic group and the pigment is weakened to compensate for the decrease in the pigment adsorptivity of the resin. Therefore, pigment dispersibility and storage stability can be improved even in an ink containing a water-soluble solvent. For example, many carbon black surfaces serving as black pigments have a carboxyl group and are strongly adsorbed by an acid-base interaction with a quaternary ammonium base of the structural unit represented by the general formula (4b).
Although the reason is not clear, the structural unit (1) represented by the general formula (1) is replaced with the structural unit (2) represented by the general formula (2) and the general formula (4a) or By copolymerizing with the structural unit (4) represented by (4b), there is a function of preventing the association of phosphonic acid groups in the polymer, and the effect of further improving the storage stability in aqueous ink. . By exhibiting these functions, the storage stability and ejection recovery property of the ink can be further improved.

  Therefore, when the polymer of the present invention is used for ink for ink jet recording, good dispersion stability and storage stability of the ink are exhibited. In addition, when ink is printed on paper, even in the case of plain paper with a low Ca ion content, the polymer in the present invention is hydrophobized by Ca ions eluted from the paper into the ink, and the general formula ( Since the structural unit represented by 2) has a high adsorptivity to the pigment, the pigment stays on the paper by agglomerating the pigment and aggregating it, and it becomes possible to realize a higher image density.

The content of the polymer in the present invention in the ink is not particularly limited and can be appropriately selected according to the purpose. However, the solid content is preferably 0.05% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass, and particularly preferably 1% by mass to 3% by mass.
When the content is 0.05% by mass or more, an effect of improving the image density is recognized.

  The polymer in the present invention is not particularly limited, and can be used as a pigment dispersant or an additive to the pigment dispersion. When used as a pigment dispersant, further improvement in image density on plain paper, storage stability with ink having a high content of water-soluble organic solvent, and ejection stability are recognized.

  The polymer content in the present invention is not particularly limited when used as a pigment dispersant, and can be appropriately selected according to the purpose. And 1 mass part-100 mass parts are preferable with respect to 100 mass parts of said pigments, 5 mass parts-80 mass parts are more preferable, and 10 mass parts-50 mass parts are still more preferable. When the content is within the more preferable range, it is advantageous in that a high image density is obtained and dispersion stability and storage stability are improved.

<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 in content in the said ink of ink, According to the objective, it can select suitably.

<Pigment>
There is no restriction | limiting in particular as said pigment, According to the objective, it can select suitably, For example, the inorganic pigment, organic pigment, etc. for black or color are mentioned. These may be used alone or in combination of two or more.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as a known method such as a contact method, a furnace method, and a thermal method. Carbon black can be used.
Examples of the organic pigment include azo pigments, azomethine pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more 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 a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofullerone pigment, and a rhodamine B lake pigment. Is mentioned.
Examples of the dye chelates include basic dye chelates and acidic dye chelates.
Examples of black materials include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide, and the like. And organic pigments such as aniline black (CI Pigment Black 1).
As the carbon black, a furnace method, a carbon black produced by the channel method, primary particle diameter of 15Nm～40nm, the BET specific surface area of ^{50m 2 / g~300m 2 / g,} DBP oil absorption amount 40 mL / 100 g Those having ˜150 mL / 100 g, volatile content of 0.5% to 10% and pH of 2 to 9 are preferred.
As the carbon black, commercially available products can be used. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, and 4 (all manufactured by Degussa).
There is no restriction | limiting in particular as a pigment which can be used for yellow ink as the thing for said colors, According to the objective, it can select suitably, for example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, and the like.
There is no restriction | limiting in particular as a pigment which can be used for a magenta ink, According to the objective, it can select suitably, For example, C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.
The pigment that can be used in the cyan ink is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.
In addition, the pigment used in the present invention may be newly produced for the present invention.
The pigment is not particularly limited, and a self-dispersing pigment in which a phosphorus-containing group such as phosphoric acid or phosphonic acid is chemically modified on the pigment surface can be used. In the present invention, a high image density can be obtained even with a pigment having no chemical modification of a phosphorus-containing group on the pigment surface, and an ink for inkjet recording excellent in storage stability and ejection recovery property can be provided.
In addition, C.I. I. Pigment Yellow 74, C.I. I. Pigment red 122, C.I. I. Pigment Bio Red 19 and C.I. I. By using CI Pigment Blue 15: 3, a well-balanced ink having excellent color tone and light resistance can be obtained.

The volume average particle diameter (D50) of the pigment is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 150 nm or less, and more preferably 100 nm or less. When the volume average particle diameter (D50) is 150 nm or less, ejection stability is improved, and occurrence of nozzle clogging and ink bending may be prevented.
Here, the 50% average particle diameter of the pigment indicates a value of D50% measured by a dynamic light scattering method with Microtrac UPA manufactured by Nikkiso Co., Ltd. in an environment of 23 ° C. and 55% RH.

  There is no restriction | limiting in particular in content of the said pigment in the said ink, Although it can select suitably according to the objective, 0.1 mass%-20 mass% are preferable, and 1 mass%-20 mass% are more preferable.

The pigment is preferably mixed with water, a pigment, and, if necessary, a dispersant, dispersed with a disperser to adjust the particle size, and then the pigment dispersion is contained in the ink.
The pigment dispersion is obtained by mixing water, a pigment, a pigment dispersant, and, if necessary, other components and then dispersing the mixture with a disperser and adjusting the particle size.
The obtained pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.
There is no restriction | limiting in particular in content of the pigment at the time of producing the said pigment dispersion, Although it can select suitably according to the objective, 0.1 mass%-50 mass% are preferable, 0.1 mass%- 30 mass% is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.
The pigment dispersant in the pigment dispersion is preferably a polymer containing a structural unit represented by the general formula (1). Other usable dispersants include, for example, various surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, naphthalenesulfonic acid Na formalin condensate, polymer type And the like.
These may be used alone or in combination of two or more.

Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurates, polyoxyalkyl ethers. Sulfate, polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate, lauryl alcohol sulfate, alkylphenol phosphate, naphthalenesulfonate formalin condensate, alkyl phosphate, alkylallylsulfone hydrochloride, Examples include diethylsulfosuccinate, diethylhexylsulfosuccinate, dioctylsulfosuccinate, and the like.
Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.
Examples of the amphoteric surfactant include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, And imidazoline derivatives.
Examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, Ether type surfactants such as oxyallylalkyl alkyl ethers; polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearic acid ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate Ester surfactants such as polyoxyethylene monooleate and polyoxyethylene stearate; 2,4,7,9-tetramethyl Acetylene glycol surfactants such as lu-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol, Etc.
Among these, naphthalenesulfonic acid Na formalin condensate is particularly preferable.
The total content of naphthalenesulfonic acid dimer, trimer, and tetramer in the naphthalenesulfonic acid Na formalin condensate is not particularly limited and can be appropriately selected according to the purpose. It is preferable that it is -80 mass%. When the content is 20% by mass or more, the dispersibility is improved and the storage stability of the ink is improved. As a result, the occurrence of nozzle clogging can be prevented. On the other hand, when the content is 80% by mass or less, the viscosity range of the ink is appropriate and the dispersibility may be good.

<Water-soluble organic solvent>
The water-soluble organic solvent has at least one of an effect as a wetting agent for preventing ink drying and an effect as a penetrating agent.
There is no restriction | limiting in particular as said water-soluble organic solvent, According to the objective, it can select suitably. For example, glycerin, ethylene glycol, diethylene glycol, isopropylideneglycerol, 1,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, propylene glycol, dipropylene glycol, trimethylolpropane, trimethylolethane, Ethylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, tetraethylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,2,6-hexanetriol, Polyhydric alcohols such as 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol; ethylene glycol monoethyl ester Polyhydric alcohol alkyl ethers such as ter, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol monophenyl ether, ethylene glycol monobenzyl Polyhydric alcohol aryl ethers such as ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, etc. Nitrogen-containing heterocyclic compounds; formamide, N-methylformamide, N, N-dimethylformamide, N, N-dimethyl- Amides such as methoxypropionamide and N, N-dimethyl-β-butoxypropionamide; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine; dimethyl sulfoxide, sulfolane, thiodiethanol and the like Sulfur-containing compounds: 3-ethyl-3-hydroxymethyloxetane, propylene carbonate, ethylene carbonate, and the like. These may be used individually by 1 type and may use 2 or more types together.

Among these, 3-ethyl-3-hydroxymethyloxetane, isopropylideneglycerol, N, N-dimethyl-β-methoxypropionamide, N, N-dimethyl-β-butoxypropion from the viewpoint of preventing curling in plain paper Amides are particularly preferred.
In addition, 1,3-butanediol, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol, triethylene glycol, and glycerin are excellent in preventing discharge failure due to moisture evaporation.
Examples of the water-soluble organic solvent having relatively low wettability and permeability include 2-ethyl-1,3-hexanediol [solubility: 4.2% (25 ° C.)], 2, 2, 4 -Trimethyl-1,3-pentanediol [solubility: 2.0% (25 ° C)], and the like.
As other polyol compounds, as aliphatic diols, for example, 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, and the like.
Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in the ink and adjusted to desired physical properties, and can be appropriately selected according to the purpose. For example, alkyl and aryl ethers of polyhydric alcohols such as diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, And lower alcohols such as ethanol.

In addition, saccharides can be contained as a wetting agent that is not a water-soluble organic solvent. Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like. Specific examples include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like. Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose. The derivatives of these saccharides are represented by the reducing sugars of the saccharides described above [for example, sugar alcohol [general formula: HOCH ₂ (CHOH) _n CH ₂ OH (where n represents an integer of 2 to 5)). The ], Oxidized sugars (eg, aldonic acid, uronic acid, etc.), amino acids, thioic acids and the like. Among these, sugar alcohol is preferable, and examples of the sugar alcohol include maltitol and sorbit.

The ratio of the pigment to the water-soluble organic solvent has a great influence on the ink ejection stability from the head. If the content of the water-soluble organic solvent is low even though the pigment solid content is high, the evaporation of water near the ink meniscus of the nozzle may progress and cause ejection failure.
The content of the water-soluble organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass to 60% by mass, and more preferably 20% by mass to 60% by mass. . When the content is 10% by mass or more, the ink ejection stability may be improved, and when it is 60% by mass or less, the drying property may be improved. The ink having the content in the more preferable numerical range has an advantage that the drying property and the ejection reliability are very good.

<Other ingredients>
There is no restriction | limiting in particular as said other component, It can select suitably as needed, For example, surfactant, pH adjuster, water-dispersible resin, antiseptic / antifungal agent, rust inhibitor, antioxidant , Ultraviolet absorbers, oxygen absorbers, light stabilizers, and the like.

-Surfactant-
The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, fluorine-based surfactants Agents, etc. Among these, nonionic surfactants and fluorine surfactants are particularly preferable.
Examples of the anionic surfactant include alkyl allyl, alkyl naphthalene sulfonate, alkyl phosphate, alkyl sulfate, alkyl sulfonate, alkyl ether sulfate, alkyl sulfosuccinate, alkyl ester sulfate, and alkylbenzene. Sulfonate, alkyl diphenyl ether disulfonate, alkyl aryl ether phosphate, alkyl aryl ether sulfate, alkyl aryl ether ester sulfate, olefin sulfonate, alkane olefin sulfonate, polyoxyethylene alkyl ether phosphate, Polyoxyethylene alkyl ether sulfate ester salt, ether carboxylate, sulfosuccinate, α-sulfo fatty acid ester, fatty acid salt, condensate of higher fatty acid and amino acid, naphthene Salt, and the like.
Examples of the cationic surfactant include alkylamine salts, dialkylamine salts, aliphatic amine salts, benzalkonium salts, quaternary ammonium salts, alkylpyridinium salts, imidazolinium salts, sulfonium salts, phosphonium salts, Etc.
Examples of the nonionic surfactant include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and the like.
Examples of the amphoteric surfactant include imidazoline derivatives such as imidazolinium betaine, dimethylalkyl lauryl betaine, alkyl glycine, alkyl di (aminoethyl) glycine, and the like.
Examples of the fluorosurfactant include materials represented by the following general formulas (I) to (III).

  However, in the said general formula (I), m represents the integer of 0-10. n represents an integer of 1 to 40.

In the general formula (II), Rf represents a fluorine-containing group, preferably a perfluoroalkyl group.
Examples of the perfluoroalkyl group preferably has a carbon number of 1 to 10, more preferably those of 1 to 3, for _example, -C _{n F 2n-1} (where, n is an integer of 1 to 10) Etc. Examples of the perfluoroalkyl group, _{e.g., -CF 3, -CF 2 CF 3} , -C 3 F 7, -C 4 F 9, and the like. Among these, —CF ₃ and —CF ₂ CF ₃ are particularly preferable.
m, n, and p each represent an integer, n is preferably 1-4, m is preferably 6-25, and p is preferably 1-4.

In the general formula (III), Rf represents a fluorine-containing group, and is preferably a perfluoroalkyl group similar to the above general formula (II). For example, CF ₃ , CF ₂ CF ₃ , C ₃ F ₇ , C ₄ such as F ₉ are preferably exemplified.
R ₂ ⁺ represents a cationic group, and examples thereof include quaternary ammonium groups; alkali metal ions such as sodium and potassium; triethylamine, triethanolamine, and the like. Among these, a quaternary ammonium group is particularly preferable. R ₁ ⁻ represents an anionic group, and examples thereof include COO ⁻ , SO ₃ ⁻ , SO ₄ ⁻ and PO ₄ ⁻ . q is preferably 1-6.
As said fluorosurfactant, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of the commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F1405 , F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont); FT-110 , FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Corporation); PF-151N (Solue) ® manufactured lens Inc. Co.); UNIDYNE DSN-403N (manufactured by Daikin Industries) and the like. Among these, Zonyl FS-300, FSN, FSN-100, FSO (all manufactured by DuPont) and Unidyne DSN-403N (manufactured by Daikin Industries) are particularly preferable from the viewpoint of improving reliability and color developability.
The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 5.0% by mass, and more preferably 0.5% by mass to 3%. The mass% is more preferable. When the content is 5.0% by mass or less, the permeability to the recording medium is improved, and it may be possible to prevent a decrease in image density and occurrence of show-through.

-PH adjuster-
The pH adjuster is not particularly limited as long as it can adjust the pH to 8.5 to 11 without adversely affecting the ink to be prepared, and can be appropriately selected according to the purpose.
Examples of the pH adjusting agent include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like.
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, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

-Water dispersible resin-
The water-dispersible resin has excellent film-forming properties (image forming properties) and has high water repellency, high water resistance, and high weather resistance, and is used for image recording with high water resistance and high image density (high color development). Useful.
Examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, natural polymer compounds, and the like.
Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin.
Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like.
Examples of the natural polymer compound include celluloses, rosins, natural rubber, and the like.
Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are preferable.
The average particle size (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and for the same composition, the viscosity at the same solid content increases as the particle size decreases.
The average particle diameter (D50) of the water-dispersible resin is not particularly limited so that the ink does not have an excessively high viscosity, and can be appropriately selected according to the purpose, but is preferably 50 nm or more.
Further, when the particle size is several tens of μm, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even though they are smaller than the nozzle opening, the ejection stability is deteriorated. Therefore, the average particle diameter (D50) is more preferably 200 nm or less in order not to disturb the ink ejection stability.
The water-dispersible resin has a function of fixing the water-dispersed colorant on the paper surface, and is preferably formed into a film at room temperature to improve the fixability of the color material.
Therefore, the minimum film-forming temperature (MFT) of the water-dispersible resin is not particularly limited and can be appropriately selected according to the purpose, but is preferably 30 ° C. or lower.
Further, when the glass transition temperature of the water-dispersible resin is -40 ° C. or lower, the resin film becomes more viscous and the printed matter is tacky. Therefore, the water-dispersible resin has a glass transition temperature of −30 ° C. or higher. It is preferable.
The content of the water-dispersible resin in the ink is not particularly limited and may be appropriately selected according to the purpose. However, the solid content is preferably 1% by mass to 15% by mass, and preferably 2% by mass to 7% by mass. % Is more preferable.

-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.

-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.

-UV absorber-
Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.

<Use of ink>
The ink of the present invention can be used for inkjet recording applications, spray coating applications, letterpress printing applications, intaglio printing applications, stencil printing applications, writing instrument applications, stamp applications, etc., and particularly preferably used for inkjet recording applications. .

(Inkjet recording method and inkjet recording apparatus)
The ink jet recording apparatus of the present invention has at least ink ejecting means for recording an image by ejecting the ink of the present invention. Specifically, the ink jet recording apparatus of the present invention includes at least a recording head and a maintenance / recovery device, and further includes other means such as a stimulus generating means and a control means as required.
The ink jet recording method of the present invention has at least an ink flying step of recording an image by flying the ink of the present invention. Specifically, it includes at least an ink flying process in which a stimulus is applied to the ink of the present invention via an ink flying means, and the ink is ejected from a recording head to record an image on a recording medium. That is, the ink jet recording method of the present invention includes at least an ink flying process and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.

Hereinafter, the details of the ink jet recording method of the present invention will be described through the description of the ink jet recording apparatus of the present invention.
The ink jet recording apparatus records an image by applying a stimulus to each ink of the present invention via an ink flying means and ejecting the ink from the nozzle of the recording head. The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned.
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, and a light. For example, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, an electrostatic force Examples include electrostatic actuators to be used.
There are no particular restrictions on the manner in which the recording ink flies, and the recording ink can be varied depending on the type of stimulus. For example, when the stimulus is “heat”, thermal energy corresponding to a recording signal is applied to the recording ink in the recording head using, for example, a thermal head, and bubbles are generated in the recording ink by the thermal energy. And the recording ink is ejected and ejected as droplets from the nozzle holes of the recording head by the pressure of the bubbles. Further, 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 bends and the volume of the pressure chamber is increased. And the recording ink is ejected and ejected as droplets from the nozzle holes of the recording head.
The size of the recording ink droplets to be ejected is preferably 3 to 40 pl, for example. Further, the speed of the discharge injection is preferably 5 to 20 m / s, the drive frequency is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

The recording head preferably includes a number of nozzles, and has either a head unit or a recording unit that discharges ink in the ink set into ink droplets by the action of energy. Further, the recording head includes a liquid chamber portion, a fluid resistance portion, a diaphragm, and a nozzle member, and at least a part of the recording head is made of a material containing any one of silicone and nickel. Preferably it is formed. The nozzle diameter of the recording head is preferably 30 μm or less, and more preferably 1 to 20 μm.
The ink jet recording apparatus of the present invention preferably has a sub tank for supplying ink onto the recording head, and the sub tank is replenished with ink from an ink cartridge through a supply tube.

  The maintenance recovery device covers at least one suction cover means (suction cap) that covers the recording head and communicates with the suction force generation means, and at least one suction cover means that covers the recording head and does not communicate with the suction force generation means Non-suction cover means (moisturizing cap) is provided, and other means are provided as necessary. Thus, by providing the suction cap and the moisture retention cap, the amount of ink consumed for the maintenance operation for ensuring reliability is less than the configuration in which all caps are suction caps, and the time required for the maintenance operation, Ink waste can be prevented. The maintenance / recovery device is not particularly limited and may be appropriately selected depending on the intended purpose. For example, those described in JP-A-2005-170035 may be used.

  The ink jet recording apparatus of the present invention preferably has a reversing unit that can perform double-sided printing by reversing the recording surface of the recording medium. Examples of the reversing means include a conveyance belt having electrostatic force, a means for holding a recording medium by air suction, and a combination of a conveyance roller and a spur. It is preferable to have an endless conveying belt and conveying means for conveying the surface of the conveying belt while charging and holding the recording medium. In this case, it is particularly preferable to charge the conveying belt by applying an AC bias of ± 1.2 kV to ± 2.6 kV to the charging roller.

  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 sequencers and computers.

Here, FIG. 1 and FIG. 2 are schematic plan views as seen from the nozzle surface showing an example of a recording head provided in the ink jet recording apparatus of the present invention. FIG. 1 shows a two-head type composed of a first head and a second head. FIG. 2 shows a four-head type including a first head, a second head, a third head, and a fourth head.
In the two-head type, either one of the first head and the second head is covered with a suction cover means (suction cap) communicating with the suction force generation means, and the other is not suctioned with no communication with the suction force generation means It is covered with a covering means (moisturizing cap). In the example of FIG. 1, the first head is covered with a suction cap, and the second head is covered with a moisture retention cap.
In the four-head type shown in FIG. 2, at least one of the first to fourth heads is covered with a suction cover means (suction cap) communicating with the suction force generation means, and the others are in communication with the suction force generation means. It is covered with non-suction cover means (moisturizing cap) that is not. In the example of FIG. 2, the first head is covered with a suction cap, and the second, third, and fourth heads are covered with a moisture retention cap.
In the two-head type shown in FIG. 1, when full-color recording is performed, yellow (Y), cyan (C), magenta (M), and black (Bk) inks are applied to a total of four nozzle rows. Each needs to be filled.

Here, an example of the ink jet recording apparatus of the present invention having the maintenance / recovery apparatus will be described with reference to FIG. FIG. 3 is an explanatory perspective view of the ink jet recording apparatus as viewed from the front side.
An ink jet recording apparatus shown in FIG. 3 includes an apparatus main body 1, a paper feed tray 2 for loading paper loaded in the apparatus main body 1, and a paper (recording medium) loaded in the apparatus main body 1 on which an image is recorded (formed). ) And a cartridge loading portion 6 that protrudes forward from the front surface 4 and is lower than the upper surface 5 on one end side of the front surface 4 of the apparatus main body 1. An operation unit 7 such as an operation key or a display is arranged on the upper surface of the cartridge loading unit 6. A main tank (hereinafter referred to as “ink cartridge”) 10 that is a liquid storage tank as a liquid replenishing unit is replaceably mounted on the cartridge loading unit 6, and has a front cover 8 that can be opened and closed. .
Here, the ink cartridge is formed by containing the ink of the present invention in a container, and other members appropriately selected as necessary can also be configured. The shape, structure, size, and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferred examples include those having at least an ink bag formed of an aluminum laminate film, a resin film, or the like.
For example, after the ink cartridge is filled into the ink bag from the ink inlet and exhausted, the ink inlet is closed by fusion. In use, the needle of the apparatus main body is pierced into an ink discharge port made of a rubber member and supplied to the apparatus. The ink bag is formed of a packaging member such as a non-permeable aluminum laminate film. The ink bag is usually housed in a plastic cartridge case and is detachably mounted on various ink jet recording apparatuses.

Next, the mechanism part of the ink jet recording apparatus of FIG. 3 will be described with reference to FIGS. FIG. 4 is a schematic configuration diagram for explaining the overall configuration of the mechanism unit, and FIG. 5 is a plan view for explaining a main part of the mechanism unit.
A carriage 33 is slidably held in the main scanning direction by a guide rod 31 which is a guide member horizontally mounted on the left and right side plates 21A and 21B constituting the frame 21 and a stay 32, and carriage scanning in FIG. 3 is performed by a main scanning motor. Move and scan in the direction (main scanning direction).
In the carriage 33, a plurality of recording heads 34, which are ink jet heads that are droplet ejection heads for ejecting ink droplets (ink droplets), are arranged in a direction crossing a plurality of nozzles with the main scanning direction, The ink droplet is ejected in the downward direction.
Here, the recording head 34 includes, for example, a recording head 34y that discharges yellow (Y) droplets, a recording head 34m that discharges magenta (M) droplets, and a recording head that discharges cyan (C) droplets. 34c, and a recording head 34k that discharges black (Bk) droplets. The “recording head 34” does not distinguish between colors. The head configuration is not limited to these examples, and it may be configured using one or a plurality of recording heads having one or a plurality of nozzle rows that eject droplets of one or a plurality of colors. .
The droplet discharge head constituting the recording head 34 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a metal phase caused by a temperature change. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging droplets can be used.
Also, the carriage 33 is equipped with sub-tanks 35y, 35m, 35c, and 35k for each color for supplying ink of each color to each recording head 34 (referred to as “sub-tank 35” when colors are not distinguished). Ink is supplied to the sub tank 35 from the ink cartridges 10 of the respective colors (referred to as “ink cartridges 10y, 10m, 10c, 10k” when different colors are distinguished) through the ink supply tubes 37 of the respective colors. I am doing so.

Here, the ink cartridge 10 is stored in the cartridge loading unit 6 as shown in FIG. The cartridge loading unit 6 is provided with a supply pump unit 23 for feeding ink in the ink cartridge 10. Further, the ink supply tube 37 from the ink cartridge loading unit 6 to the sub tank 35 is fixed and held by the main body side holder 25 on the rear plate 21C constituting the frame 21 in the middle of rolling. Further, it is fixed on the carriage 33 by the fixing rib 26.
4 and 5, reference numeral 22 denotes a flexible cable, and reference numeral 36 denotes an ink supply tube (sub tank connecting portion).
On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (bottom plate) 41 of the paper feed tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. The sheet roller 43 and the sheet feeding roller 43 are opposed to each other, and a separation pad 44 made of a material having a large friction coefficient is provided. The separation pad 44 is urged toward the sheet feeding roller 43 side.
As a transport unit for transporting the paper 42 fed from the paper feed unit on the lower side of the recording head 34, a transport belt 51 for transporting the paper 42 by electrostatic adsorption, and a paper feed unit The counter roller 52 for transporting the paper 42 fed through the guide 45 while sandwiching it between the transport belt 51 and the paper 42 fed substantially vertically upward are changed by approximately 90 ° and copied onto the transport belt 51. A conveying guide 53 for adjusting the pressure and a tip pressing roller 55 urged toward the conveying belt 51 by a pressing member 54. In addition, a charging roller 56 that is a charging unit for charging the surface of the conveyance belt 51 is provided.
Here, the conveyance belt 51 is an endless belt, and is configured to be looped around the conveyance roller 57 and the tension roller 58 in the belt conveyance direction of FIG. The charging roller 56 is disposed so as to contact the surface layer of the conveyor belt 51 and rotate following the rotation of the conveyor belt 51, and applies 2.5N to both ends of the shaft as pressure.
In addition, a guide member 61 is disposed on the back side of the conveyance belt 51 so as to correspond to a printing area by the recording head 34. The upper surface of the guide member 61 protrudes closer to the recording head 34 than the tangent line of the two rollers (the conveyance roller 57 and the tension roller 58) that support the conveyance belt 51. As a result, the conveyance belt 51 is pushed up and guided by the upper surface of the guide member 61 in the printing region, so that highly accurate flatness is maintained.
Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 71 for separating the paper 42 from the conveying belt 51, a paper discharge roller 72, and a paper discharge roller 73 are provided. A paper discharge tray 3 is provided below the paper discharge roller 72. Here, the height from between the paper discharge roller 72 and the paper discharge roller 73 to the paper discharge tray 3 is increased to some extent in order to increase the amount that can be stored in the paper discharge tray 3.
A double-sided paper feeding unit 81 is detachably attached to the back surface of the apparatus body 1. The double-sided paper feed unit 81 takes in the paper 42 returned by the reverse rotation of the transport belt 51, reverses it, and feeds it again between the counter roller 52 and the transport belt 51. A manual paper feed unit 82 is provided on the upper surface of the duplex paper feed unit 81.

Further, as shown in FIG. 5, in a non-printing area on one side of the carriage 33 in the scanning direction, a maintenance / recovery device (hereinafter referred to as “sub-system”) for maintaining and recovering the nozzle state of the recording head 34. 91 is also provided. The sub-system 91 includes cap members (hereinafter also referred to as “caps”) 92a to 92d for capping each nozzle surface of the recording head 34 (referred to as “caps 92” when not distinguished). A wiper blade 93 that is a blade member for wiping the nozzle surface, and an empty space that receives a droplet when performing an empty discharge that discharges a droplet that does not contribute to recording in order to discharge the thickened ink. A wiper cleaner 95 (see FIG. 7), which is formed integrally with the discharge receiver 94 and the idle discharge receiver 94 and removes ink adhering to the wiper blade 93, and the wiper blade 93 when the wiper blade 93 is cleaned. Provided with a cleaner roller 96 that constitutes a cleaner means to be pressed against the wiper cleaner 95 side. That.
Further, as shown in FIG. 5, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge ink that has been thickened during recording or the like. An empty discharge receiver 98 for receiving the droplets is disposed, and the empty discharge receiver 98 is provided with an opening 99 and the like along the nozzle row direction of the recording head 34.
In the ink jet recording apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feeding tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and the transport belt 51 and the counter roller 52 to be conveyed between the two. Further, the front end of the paper 42 is guided by the transport guide 53 and pressed against the transport belt 51 by the front end pressure roller 55, and the transport direction is changed by approximately 90 °.
At this time, a positive voltage and a negative output are alternately repeated from the high voltage power source to the charging roller 56 by the control circuit, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 51 alternates, that is, a rotating direction. In the sub-scanning direction, plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the sheet 42 is electrostatically attracted to the conveyance belt 51, and the sheet 42 is moved in the sub-scanning direction by the circular movement of the conveyance belt 51. Be transported. Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, the next Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.
Further, during printing (recording) standby, the carriage 33 is moved to the subsystem 91 side, the recording head 34 is capped by the cap member 92, and the nozzles are kept in a wet state to prevent ejection failure due to ink drying. . In addition, a recovery operation is performed in which ink is sucked from the nozzles (referred to as “nozzle suction” or “head suction”) while the recording head 34 is capped by the cap member 92 and the thickened ink and bubbles are discharged. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 34 is maintained.

Next, an outline of the configuration of the subsystem 91 including the maintenance / recovery device in the inkjet recording apparatus of the present invention will be described with reference to FIGS. 6 is an explanatory plan view of the main part of the system, FIG. 7 is a schematic schematic configuration diagram of the system, and FIG. 8 is an explanatory diagram on the right side of FIG.
A frame (maintenance device frame) 111 of the subsystem 91 includes two cap holders 112A and 112B as a cap holding mechanism, a wiper blade 93 as a wiping member including an elastic body as a cleaning means, and a carriage lock 115. Are held up and down (movable up and down). An empty discharge receiver 94 is disposed between the wiper blade 93 and the cap holder 112 </ b> A, and the wiper blade 93 is a cleaning member for the empty discharge receiver 94 from the outside of the frame 111 in order to clean the wiper blade 93. A wiper cleaner 118 that is a cleaner means including a cleaner roller 96 that is a cleaning member to be pressed against the wiper cleaner 95 side is swingably held.
The cap holders 112A and 112B (referred to as “cap holder 112” when not distinguished from each other) hold two caps 92a and 92b and caps 92c and 92d for capping the nozzle surfaces of the two recording heads 34, respectively. .
Here, a tubing pump (suction pump) 120 as a suction means is connected to the cap 92a held by the cap holder 112A closest to the printing area via a flexible tube 119, and the other caps 92b, 92c, 92d does not connect the tubing pump 120. That is, only the cap 92a is a suction (recovery) and moisturizing cap (hereinafter also referred to as “suction cap”), and the other caps 92b, 92c, and 92d are all just a moisturizing cap. Therefore, when performing the recovery operation of the recording head 34, the recording head 34 that performs the recovery operation is selectively moved to a position where it can be capped by the suction cap 92a.
A cam shaft 121 rotatably supported by the frame 111 is disposed below the cap holders 112A and 112B. Cap cams 122A and 122B for raising and lowering the cap holders 112A and 112B are disposed on the cam shaft 121. A wiper cam 124 for raising and lowering the wiper blade 93, a carriage lock cam 125 for raising and lowering the carriage lock 115 via the carriage lock arm 117, and an empty liquid droplet that is idlely discharged in the idle discharge receiver 94. A roller 126 as a rotating body, which is a discharge landing member, and a cleaner cam 128 for swinging the wiper cleaner 118 are provided.
Here, the cap 92 is moved up and down by the cap cams 122A and 122B. The wiper blade 93 is moved up and down by the wiper cam 124, and the wiper cleaner 118 is advanced when the wiper blade is lowered. The wiper blade 93 descends while being sandwiched between the cleaner roller 96 of the wiper cleaner 118 and the wiper cleaner 95 of the idle discharge receiver 94. Ink adhering to 93 is scraped off into the empty ejection receiver 94.
The carriage lock 115 is urged upward (in the locking direction) by a compression spring, and is raised and lowered via a carriage lock arm 117 driven by a carriage lock cam 125.
Then, in order to rotationally drive the tubing pump 120 and the cam shaft 121, the motor gear 132 provided on the motor shaft 131a rotates the motor 131 and the pump gear 133 provided on the pump shaft 120a of the tubing pump 120 is meshed. An intermediate gear 136 with a one-way clutch 137 is engaged with an intermediate gear 134 integral with 133 via an intermediate gear 135, and the intermediate gear 138 coaxial with the intermediate gear 136 is fixed to the camshaft 121 via the intermediate gear 139. The cam gear 140 is engaged. An intermediate shaft 141 that is a rotation shaft of the intermediate gears 136 and 138 with the clutch 137 is rotatably held by the frame 111.
Further, the cam shaft 121 is provided with a home position sensor cam 142 for detecting the home position, and the home position lever is operated when the cap 92 comes to the lowest end by the home position sensor provided in the subsystem 91. The sensor is opened and the home position of the motor 131 (other than the pump 120) is detected. Note that when the power is turned on, the position moves up and down (up and down) regardless of the position of the cap 92 (cap holder 112), the position is not detected until the movement starts, and the position is determined after detecting the home position of the cap 92 (on the way up). To the bottom end. Thereafter, the carriage moves left and right, returns to the cap position after position detection, and the recording head 34 is capped.
Reference numeral 142 denotes a home position sensor cam.

Next, details of the holding mechanism of the cap 92 and the lifting mechanism (vertical movement mechanism) will be described with reference to FIG. FIG. 9 is an explanatory side view of the cap holding lifting mechanism.
The cap holder 112A, which is a cap holding mechanism, includes a holder 151 that holds the cap 92a and the cap 92b (sometimes collectively referred to as “cap 92A”) so as to be movable up and down, a bottom surface of the holder 151, and a bottom portion of the cap 92A. And a slider 152 that holds the holder 151 movably in the front-rear direction (the direction in which the nozzles of the recording head 34 are arranged).
The cap 92A is inserted into the guide groove 150 (not shown) of the holder 151 so that the guide pin 150a provided at both ends can be moved up and down, and the guide shaft 150b provided on the bottom surface is inserted into the holder 151 so as to be movable up and down. It is mounted so that it can move up and down. The springs 152, 152 interposed between the cap 92A and the cap holder 151 urge the caps 92a, 92b upward (in the direction of pressing toward the nozzle surface when capping).
The slider 153 is configured such that the guide pins 154 and 155 provided at the front and rear ends are slidably fitted in guide grooves 156 formed in the frame 111 so that the slider 153, the holder 151, and the entire cap 92A can be moved up and down.
Then, the cam pin 157 provided on the lower surface of the slider 153 is fitted in a cam groove (not shown) of the cap cam 122A, and the slider 153 is rotated by the rotation of the cap cam 122A that is synchronized with the rotation of the cam shaft 121 to which the rotation of the motor 131 is transmitted. The holder 151 and the cap 92A move up and down.
Further, the slider 153 and the holder 151 are inserted into the suction cap 92a, and the tube 119 is wound around and connected from below the center position of the cap in the short direction of the cap 92a.
The cap holder 112B that holds the caps 92c and 92d (which may be collectively referred to as “cap 92B”) and the configuration that moves the cap holder 112B up and down are the same as described above, and a description thereof will be omitted. However, the tube 119 is not connected to the caps 92c and 92d. Thus, by driving the motor 131 which is one drive source, the cam shaft 121 which is one shaft rotates, and the cams 122A and 122B fixed to the cam shaft 121 are rotated by the rotation of the cam shaft 121. The cap 92A and the cap 92B move up and down.

  The ink jet recording apparatus and the ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method, and are particularly suitable for, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, and a printer / fax / copier multifunction machine. Can be applied to.

-Ink recordings-
The ink recorded matter recorded by the ink jet recording method of the present invention is the ink recorded matter of the present invention. The ink recorded matter of the present invention has an image recorded with the ink of the present invention on a recording medium.
The recording medium used in the present invention is not particularly limited as long as the ink of the present invention is landed and an image can be formed. For example, plain paper, coated paper for printing, glossy paper, special paper and the like can be mentioned. The paper exemplified above contains calcium carbonate, talc, kaolin, aluminum sulfate (sulfuric acid band), and the like. When the ink jet recording ink of the present invention lands on the paper, a polyvalent metal ion, specifically In the sample, divalent or trivalent metal ions such as calcium, magnesium and aluminum are eluted.
As mentioned above, the present invention can be used with any paper, but plain paper is particularly preferred. Here, “plain paper” means an image forming apparatus for office use, home use or personal use using hard copy forming technology such as an electrophotographic copying machine, a simple offset printing machine, a printer, or a conventional diazo copying machine. In general, it refers to all paper media for supporting images with paper-passability and transportability. Plain paper seems to be the reason for Plain Paper, but today the mainstream of Plain Paper is high-quality paper. Therefore, high-quality paper is often referred to as plain paper, and an electrophotographic image medium as a typical image forming technique using the high-quality paper is popularly abbreviated as PPC (plain paper copy).
The ink in the present invention reacts with the above polyvalent metal ions to aggregate the pigment, and a high image density can be obtained. However, it is difficult to achieve high image density, for example, with plain paper among the papers exemplified above.
Many of the fillers and sizing agent fixing agents contained in plain paper are poorly water-soluble metal salts. Moreover, even if a water-soluble metal salt is contained, the content is small. Therefore, plain paper has less elution of polyvalent metal ions compared to paper processed with water-soluble polyvalent metal salt or the like on the paper surface, and the prior art cannot provide an effect of improving image density.
In the present invention, a high image density can be realized not only on the processed paper but also on paper with less elution of polyvalent metal ions such as plain paper. Examples of commercially available plain paper include high-quality paper My Paper (manufactured by Ricoh Co., Ltd.) and Xerox 4024 (manufactured by Fuji Xerox Co., Ltd.).

The ink of the present invention is preferably used for paper having an amount of Ca ions eluted from the paper of 1.0 × 10 ^{−4 to} 5.0 × 10 ⁻⁴ [g / g]. When the Ca ion amount is 1.0 × 10 ⁻⁴ [g / g] or more, the effect of improving the image density by reaction aggregation with the pigment dispersant is improved. In addition, when the Ca ion amount is 5.0 × 10 ⁻⁴ [g / g] or less, the penetration of the ink into the paper is not inhibited, so that the drying property of the ink is improved, and the scratch resistance and the marker resistance are also improved. improves.
The amount of Ca ions eluted from the paper is calculated by the following method.
That is, the paper is filtered into a 2.5 cm (± 0.5 cm) × 3.5 cm (± 0.5 cm) square piece of paper, and the pure water is filtered through a 0.8 μm cellulose acetate filter (manufactured by Advantech Co., Ltd.). Then, the Ca ions contained in the immersion liquid are quantified by an ICP emission spectroscopic analyzer. The Ca ion concentration [ppm] obtained here is multiplied by 200 g, which is the weight of high-purity water, and is further divided by 16 g, which is the weight of the immersed paper. The amount of Ca ions eluted from the paper [g / g ] Is calculated.
For example, the amount of Ca ions of MyPaper (manufactured by Ricoh Co., Ltd.) is 4.3 × 10 ⁻⁴ [g / g], and the amount of Ca ions of Xerox 4024 (manufactured by Fuji Xerox Co., Ltd.) is 1.7 × 10 ⁻⁴ [ g / g].

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. “Part” represents “part by mass” unless otherwise specified. “%” Represents “% by mass” unless otherwise specified.

<Synthesis of monomer>
[Raw material synthesis]
Synthesis of aminomethylene diphosphonic acid 68.4 parts of phosphorous acid, 25 parts of formamide and 200 parts of chlorobenzene were placed in a reaction vessel and stirred at 100 ° C. for 1 hour while purging with nitrogen. Thereafter, the mixture was cooled to 30 ° C., and 152.8 parts of phosphorus trichloride was slowly added dropwise. Thereafter, the mixture was further stirred at 60 ° C. for 3 hours. After cooling, the solution was removed, and 200 parts of water was added to the remaining highly viscous residue while cooling with water, dissolved, and heated to reflux for 4 hours. After cooling, the target crystal precipitated. This was collected by filtration and dried to obtain 50.3 parts of the desired product. Mass spectrometry by ESI showed m / z (+) 191.75, which was in agreement with the calculated molecular weight of 191.02 + 1 in the error range.

[Monomer 1-1: Methacrylamidomethylenediphosphonic acid ditetraethylammonium salt]
Into a reaction vessel, 19.2 parts of aminomethylene diphosphonic acid was added, and then an aqueous solution in which 179.8 parts of tetraethylammonium hydroxide (Tokyo Kasei Co., Ltd., 35% aqueous solution) was dissolved in 83.1 parts of ion-exchanged water was added. The solution was completely dissolved with stirring. Next, 13.5 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise while cooling the flask to 5 ° C. After completion of the dropwise addition, the mixture was further stirred for 30 minutes, and then 14.55 parts of concentrated hydrochloric acid was added dropwise while cooling. The reaction solution was extracted and washed three times with methylene chloride, the remaining aqueous solution was dropped into 750 parts of acetone, and the desired product was separated by decantation. Water was removed by an evaporator to obtain 49.5 parts of the target product.
1.1 parts of this product was dissolved in 110 parts of ion-exchanged water, neutralized with 0.1N KOH methanol solution using thymolphthalein (manufactured by Kanto Chemical Co., Inc.) as an indicator, and the acid value was 107. . This result was equivalent to 108 mg KOH / g calculated on the assumption that the four acidic groups were two tetraethylammonium salts.

[Monomer 1-2: Acrylamide methylenediphosphonic acid ditetra-n-butylammonium salt]
In the synthesis of monomer 1-1, instead of using 13.5 parts of methacrylic acid chloride, 11.6 parts of acrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) is used, and tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd., 35%). Aqueous solution) Instead of 179.8 parts and 83.1 parts of ion-exchanged water, 277.2 parts of tetrabutylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd., 40% aqueous solution) and 33.7 parts of ion-exchanged water were used. Similarly, 65 parts of the target product was obtained.

[Preparation of Monomer 2-1 Synthesis of 2-naphthoic acid-2-hydroxyethyl ester]
62.0 g (525 mmol) of 1,6-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 700 mL of methylene chloride, and 20.7 g (262 mmol) of pyridine was added.
To this solution, a solution prepared by dissolving 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of methylene chloride was dropped with stirring over 2 hours, and then stirred at room temperature for 6 hours. . After the obtained reaction solution was washed with water, the organic phase was isolated and dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 98/2) as an eluent to obtain 52.5 g of 2-naphthoic acid-2-hydroxyethyl ester.

[Synthesis of Monomer 2-1]
Next, 42.1 g (155 mmol) of 2-naphthoic acid-2-hydroxyethyl ester was dissolved in 80 mL of dry methyl ethyl ketone and heated to 60 ° C. To this solution, a solution of 24.0 g (155 mmol) of 2-methacryloyloxyethyl isocyanate (produced by Showa Denko KK, Karenz MOI) dissolved in 20 mL of dry methyl ethyl ketone was added dropwise with stirring over 1 hour, and then 70 ° C. For 12 hours. After cooling to room temperature, the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent, and 57.0 g of monomer 2- having a structure represented by the following structural formula 1 1 was obtained.

[Synthesis of Monomer 2-2]
Monomer 2-2 having a structure represented by the following structural formula 2 is obtained in the same manner as monomer 2-1, except that ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) is used instead of 1,6-hexanediol. It was.

[Synthesis of Monomer 2-3]
Monomer 2 having a structure represented by the following structural formula 3 in the same manner as monomer 2-1, except that 1,12-dodecanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 1,6-hexanediol. -3 was obtained.

[Synthesis of Monomer 2-4]
Monomer 2 having a structure represented by the following structural formula 4 in the same manner as monomer 2-1, except that 1,16-hexadecanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 1,6-hexanediol. -4 was obtained.

<Synthesis of copolymer polymer having diphosphonic acid group>
[Synthesis Example 1; Synthesis of copolymer polymer 1 having diphosphonic acid group]
36 parts of the monomer 2-1 was placed in a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, and dissolved in 370 parts of N, N-dimethylformamide (DMF). Thereto was added an aqueous solution in which 24 parts of monomer 1-1 was dissolved in 75 parts of ion exchange water, and the mixture was heated to 75 ° C. in an argon atmosphere. A DMF solution in which 1.3 parts of 2,2′-azobisisobutyronitrile (AIBN) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 30 parts of DMF was added dropwise using a dropping funnel. Stirring was continued at 75 ° C. for 6 hours, followed by cooling to stop the polymerization.
Insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixed solution of tetrahydrofuran and hexane (volume ratio 40: 100). Subsequently, after removing the solvent with an evaporator, it was vacuum dried at 60 ° C. to obtain 56 parts of resin.
When 1 part of this resin was dissolved in 100 parts of ion-exchanged water and titrated with 0.1NKOH methanol solution using thymolphthalein as an indicator, the acid value was 43 mgKOH. It was in good agreement with the value of 43 mg KOH calculated from the acid value of monomer 1-1 as copolymerized according to the charge ratio.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while neutralizing with an aqueous tetraethylammonium hydroxide solution. When the viscosity of this solution was measured at 25 ° C., it was 2.3 mPa · s. The 10% by mass resin aqueous solution thus obtained was used for preparing a pigment dispersion.
From the titration result of the monomer raw material alendronic acid, it can be seen that three of the four OH groups of the phosphonic acid are neutralized when the color of thymolphthalein is discolored. Of the four OH groups, three are neutralized with tetraethylammonium ions.

[Synthesis Example 2 (Synthesis of Polymer 2) to Synthesis Example 16 (Synthesis of Polymer 16)]
As shown in Table 1, the mass% of the monomer (1) of the general formula (5) and the mass% of the monomer (2) of the general formula (6) were respectively changed and synthesized under the reaction conditions shown in Table 2. Others were carried out similarly to the synthesis example 1, and synthesize | combined the polymers 2-16.
As the chain transfer agent, α-thioglycerol manufactured by Tokyo Chemical Industry Co., Ltd. was used.
Each of the obtained polymers 2 to 16 was neutralized to a salt composition as shown in Table 1 (M in the general formula (1)) or not used for preparation of a pigment dispersion as it was. Table 1 shows the viscosities at 25 ° C. of 10% by mass aqueous solutions of the respective polymers 2 to 16.

  In Table 1, TetraEtA represents tetraethylammonium ion and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H, etc., M + represents 3 TetraEtA ions and 1 proton.

[Comparative Synthesis Example 1; Polymer 17]
Polymer 17 of Comparative Synthesis Example 1 was synthesized according to Example 5 of JP-T-2009-513802 which is publicly known.

[Comparative Synthesis Example 2; Polymer 18]
The polymer 18 of Comparative Synthesis Example 2 was synthesized according to Example 1 of JP-T-2009-513802 which is publicly known.

[Synthesis of Monomer 5 for Comparative Synthesis Example]
Place 25 parts of alendronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) into the flask, and then add an aqueous solution consisting of 179.8 parts of tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd., 35% aqueous solution) and 83.1 parts of ion-exchanged water. And dissolved completely with stirring. Next, 13.32 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise while cooling the flask to 5 ° C. After completion of the dropwise addition, the mixture was further stirred for 30 minutes, and then 14.53 parts of concentrated hydrochloric acid was added dropwise while cooling. The reaction solution was extracted and washed with methylene chloride three times, and the remaining aqueous solution was dropped into 800 parts of methanol to precipitate the desired product. By filtration, 55 parts of tetraethylammonium 1-hydroxy-4-methacrylamidebutane-1,1-diylbis (hydrogen phosphonate) as the target product monomer 5 was obtained.

[Comparative Synthesis Example 3; Synthesis of Polymer 19]
In a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, 450 parts of N, N-dimethylformamide (DMF) was placed under an argon atmosphere and heated to 75 ° C. Thereto, 558 parts of an aqueous solution of 75 parts of the comparative synthesis monomer 5, 525 parts of a DMF solution of 75 parts of benzyl acrylate, and 464 parts of a DMF solution in which 14 parts of 2,2′-azobisisobutyronitrile are dissolved are each 12 times. Added every 30 minutes. Stirring was continued for an additional 4 hours after all had been added, and then the polymerization was stopped by cooling.
The precipitate was collected by filtration, washed with hexane, and dried to obtain 140 parts of a copolymer (Polymer 19). The obtained resin was subjected to acid value measurement in the same manner as in the synthesis example, neutralized with an aqueous tetraethylammonium hydroxide solution, and used as a resin solution.

[Comparative Synthesis Example 4; Synthesis of Polymer 20]
In a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, 182 parts of N, N-dimethylformamide (DMF, manufactured by Kanto Chemical Co., Inc.) was placed in an argon atmosphere and heated to 75 ° C. Thereto, 223 parts of an aqueous solution prepared by dissolving 30 parts of the comparative synthesis monomer 5 in 193 parts of water, 24 parts of benzyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and N- [3- (dimethylamino) propyl] acrylamide (Tokyo) 2 parts DMF solution in which 6 parts are dissolved in 182 parts DMF and 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry / hereinafter abbreviated as AIBN) 5 187.4 parts of a DMF solution in which 4 parts were dissolved in 182 parts of DMF were added in 12 portions and added every 30 minutes. Stirring was further continued at 75 ° C. for 4 hours after all the addition was completed, and then the polymerization was stopped by cooling.
Then, it processed like the comparative synthesis example 3, and used as a resin solution.

[Synthesis of Monomer 6 for Comparative Synthesis Example]
25 parts of alendronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in the flask, and then an aqueous solution in which 17.1 parts of sodium hydroxide was dissolved in 200 parts of ion-exchanged water was added and completely dissolved while stirring. Next, 13.32 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly added dropwise while cooling the flask to 5 ° C. After completion of the dropwise addition, the mixture was further stirred for 30 minutes, and then 14.53 parts of concentrated hydrochloric acid was added dropwise while cooling. The reaction solution was extracted and washed with methylene chloride three times, and the remaining aqueous solution was dropped into 800 parts of methanol to precipitate the desired product. By filtration, 35 parts of sodium 1-hydroxy-4-methacrylamidebutane-1,1-diylbis (hydrogen phosphonate) as the target monomer 6 was obtained.

[Comparative Synthesis Example 5; Synthesis of Polymer 21]
In a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, 193 parts of N, N-dimethylformamide (DMF) was placed under an argon atmosphere and heated to 75 ° C. Thereto, 223 parts of an aqueous solution prepared by dissolving 30 parts of the monomer 6 for Comparative Synthesis Example in 193 parts of water, 24 parts of benzyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and trimethyl-2-methacryloyloxyethylammonium chloride (Tokyo Chemical Industry) (TMMEAC) 6 parts dissolved in 182 parts DMF and 212 parts DMF solution and 2,2'-azobisisobutyronitrile (Tokyo Chemical Industry Co., Ltd.) 5.4 parts dissolved in 182 parts DMF 187.4 parts of the DMF solution was added in 12 portions and added every 30 minutes. Stirring was further continued at 75 ° C. for 4 hours after all the addition was completed, and then the polymerization was stopped by cooling.
Then, it processed similarly to the comparative synthesis example 3 except neutralizing using sodium hydroxide, and used as the resin solution.

[Comparative Synthesis Example 6; Synthesis of Polymer 22]
In Comparative Synthesis Example 5, polymerization and treatment were performed in the same manner except that stearyl acrylate was used instead of benzyl acrylate and DMAPAA was used instead of TMMEAC, and used as a resin solution.

[Comparative Synthesis Example 7; Polymer 23]
The polymer 23 of Comparative Synthesis Example 7 was synthesized according to Example 7 of JP-A-2014-114409 which is publicly known.

<Preparation example of pigment dispersion>
[Preparation of Pigment Dispersion 1]
After premixing the following mixture, it was circulated and dispersed for 10 minutes at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, medium: zirconia ball having a diameter of 0.1 mm), and then the pore size was 1 A pigment dispersion 1 was obtained by filtration through a 2 μm membrane filter.
Carbon black (NIPEX 160, manufactured by Degussa) ... 16.0 parts by mass A 10% by weight aqueous solution of polymer 1 ... 40.0 parts by weight Pure water ... 44.0 parts by weight

[Preparation of pigment dispersion 2 to pigment dispersion 18]
In the same manner as in the preparation of pigment dispersion 1, pigment dispersion 2 to pigment dispersion 18 were prepared according to the formulation shown in Table 3.
In Table 3, the following products were used as pigments other than carbon black.
-Pigment Blue 15: 3 Chromo Fine Blue A-220JC, manufactured by Dainichi Seika Co., Ltd.- Pigment Red 122 Toner Magenta EO02, manufactured by Clariant, Inc.- Pigment Yellow 74 First Yellow 531, manufactured by Dainichi Seika Co., Ltd.

<Preparation of ink for ink jet recording>
[Example 1]
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter having a pore size of 1.2 μm to obtain an ink.
・ Pigment Dispersion 1 (Pigment solid content 16% by mass) ······ 40.0 parts by mass · Glycerin (water-soluble organic solvent) ········· ··· 10.0 parts by mass · 1,3-butanediol (water-soluble organic solvent) ······· 20.0 parts by mass · 2-ethyl-1,3-hexanediol (water-soluble organic solvent) ) ... 1.0 parts by mass. 2,2,4-trimethyl-1,3-pentanediol .... 1.0 parts by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
・ Distilled water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 27.0 parts by mass

[Examples 2 to 21]
Inks of Examples 2 to 21 were prepared according to the formulation (parts by mass) shown in Table 4 using the same preparation method as in Example 1.

[Example 22]
Using the same preparation method as in Example 1, the ink of Example 22 was prepared according to the formulation shown below.
・ Pigment Dispersion 22 (Pigment solid content 16% by mass) ・ ・ ・ ・ ・ ・ 40.0 parts by mass ・ Glycerin (water-soluble organic solvent) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・-10.0 parts by mass-1,3-butanediol (water-soluble organic solvent) ... 20.0 parts by mass-2-ethyl-1,3-hexanediol (water-soluble organic solvent)・ ・ ・ 1.0 part by mass ・ 2,2,4-trimethyl-1,3-pentanediol ・ ・ ・ 1.0 part by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
・ 10% by weight aqueous solution of polymer 1 ・ ・ ・ ・ ・ ・ 16.0 parts by weight ・ Distilled water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... 11.0 parts by mass

[Comparative Example 1]
Using the same preparation method as in Example 1, the ink of Comparative Example 1 was prepared according to the formulation shown in Table 4. That is, in this example, instead of polymer 1 in the formulation of pigment dispersion 1, pigment dispersion 23 using polymer 17 according to comparative synthesis example 1 was used.

[Comparative Example 2-7]
Using the same preparation method as in Comparative Example 1, an ink of Comparative Example 2-7 was prepared according to the formulation shown in Table 4. That is, in this example, pigment dispersion 24-29 using polymer 18-23 from Comparative Synthesis Example 2-7 was used.

[Evaluation results]
Next, the inkjet inks of Examples 1 to 22 and Comparative Examples 1 to 7 were evaluated by the following evaluation method. The results are shown in Table 5 below.

<Image density>
64 point character JIS X 0208 (1997), 2223, which was prepared by using Microsoft Word 2000 (manufactured by Microsoft) by filling ink prepared in an ink jet printer (manufactured by Ricoh Co., Ltd., IPSiO GX5000) under an environment of 23 ° C. and 50% RH. Are printed on plain paper 1 (XEROX 4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and the general symbols of JIS X 0208 (1997), 2223 on the printing surface are printed. The color of the part was measured with X-Rite 938 (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.
〔Evaluation criteria〕
(black)
A: 1.25 or more.
B: 1.20 or more and less than 1.25.
C: 1.10 or more and less than 1.20.
D: Less than 1.10.
E: The pigment is gelled and cannot be dispersed in the ink and cannot be printed.
(yellow)
A: 0.80 or more.
B: 0.75 or more and less than 0.80.
C: 0.70 or more and less than 0.75.
D: Less than 0.70.
E: The pigment is gelled and cannot be dispersed in the ink and cannot be printed.
(Magenta)
A: 0.95 or more.
B: 0.85 or more and less than 0.95.
C: 0.75 or more and less than 0.85.
D: Less than 0.75.
E: The pigment is gelled and cannot be dispersed in the ink and cannot be printed.
(cyan)
A: 1.05 or more.
B: 0.95 or more and less than 1.05.
C: 0.85 or more and less than 0.95.
D: Less than 0.85.
E: The pigment is gelled and cannot be dispersed in the ink and cannot be printed.

  C or higher is practical.

<Preservation of pigment dispersion>
Each pigment dispersion was put in a polyethylene container, sealed, stored at 70 ° C. for 2 weeks, the rate of change in viscosity after storage with respect to the viscosity before storage was determined from the following formula, and evaluated according to the following criteria.
Viscosity change rate (%) = (viscosity of pigment dispersion after storage / viscosity of pigment dispersion before storage) × 100
The viscosity was measured using a viscometer (RE500L, manufactured by Toki Sangyo Co., Ltd.), adjusted to 50 or 100 rotations according to the viscosity of the sample, and evaluated based on the following criteria. .
[Evaluation criteria]
A: Viscosity change rate is within ± 5%.
B: Viscosity change rate exceeds ± 5% and within ± 8%.
C: Viscosity change rate exceeds ± 8% and within ± 10%.
D: Viscosity change rate exceeds ± 10% and within ± 30%.
E: Viscosity change rate exceeds ± 30% (evaluates due to gelation).

  C or higher is practical.

<Ink storage stability>
Each ink was filled in an ink cartridge, stored at 60 ° C. for 1 week, and stored at 70 ° C. for 2 weeks.
Viscosity change rate (%) = (ink viscosity after storage / ink viscosity before storage) × 100
The viscosity was measured using a viscometer (RE500L, manufactured by Toki Sangyo Co., Ltd.), adjusted to 50 or 100 rotations according to the viscosity of the sample, and evaluated based on the following criteria. .
[Evaluation criteria]
A: Viscosity change rate is within ± 5%.
B: Viscosity change rate exceeds ± 5% and within ± 8%.
C: Viscosity change rate exceeds ± 8% and within ± 10%.
D: Viscosity change rate exceeds ± 10% and within ± 30%.
E: Viscosity change rate exceeds ± 30% (evaluates due to gelation).

In Table 5, the storage evaluation result at 60 ° C. for 1 week is described as “ink storage stability 1”, and the storage evaluation result at 70 ° C. for 2 weeks is described as “ink storage stability 2”.
C or higher is practical.

<Discharge recovery>
After filling each ink of Examples 1 to 22 and Comparative Examples 1 to 7 in an inkjet printer and leaving it in an HL environment (32 ± 0.5 ° C., 15 ± 5% RH) for 3 hours, printing a nozzle check pattern It was confirmed that there was no discharge failure such as missing dots or bent flight. Then, it was further left for 6 days. After completion of standing, a nozzle check pattern with a solid print part is applied to high-quality paper Mypaper (made by Ricoh Co., Ltd.) with a basis weight of 69.6 g / m ² , a sizing degree of 23.2 seconds, and an air permeability of 21.0 seconds. Sheets were printed and the presence or absence of missing dots or flying curves was confirmed. When there were missing ink dots or flying bends in the nozzle check pattern, the printer nozzle was cleaned as a return to normal printing, and the total number was evaluated. From the total number of times obtained, the ejection recovery property of each ink was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: Zero cleaning.
B: Cleaning once.
C: Cleaning twice.
D: Cleaning is performed 3 times or more and less than 5 times.
E: Cleaning 5 times or more.

  C or higher is practical.

From the results shown in Table 5, the inks of the examples having the configuration of the present invention are in practical use areas such as image density, dispersion stability, ink storage stability, and ejection recovery properties, and have excellent practicality. It can be seen that In particular, it can be seen that the storage stability and ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those in which the monomer content represented by the general formula (1) and the viscosity are controlled in a suitable range have particularly high evaluation results (Examples 1 to 8, 10, 13, 14, 21). ) The overall quality is improved. When the content and viscosity are out of the preferred ranges, the image density, storage stability, and ejection recovery performance are slightly reduced, but at a practicable level.
The ink of Example 22 using the polymer having a diphosphonic acid group of the present invention as an additive shows a slight deterioration in quality as a whole as compared with the other examples using as a pigment dispersant. Is a level.
On the other hand, those that do not have the configuration of the present invention are inferior in ink storage stability and ejection recovery properties (Comparative Examples 1 to 7). Even if the image density does not show a significant deterioration in quality, the long-term storage and ejection recovery properties of the ink are not at a practicable level.

[Synthesis Example 17; Synthesis of Copolymer Polymer 24 Containing Phosphonic Acid Group]
In a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, 30 parts of monomer 2-1 and 6 parts of dimethylacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd., DMAM) are placed, and 500 parts of N, N-dimethylformamide. Dissolved in (DMF). Thereto was added an aqueous solution in which 24 parts of monomer 1-1 was dissolved in 100 parts of ion exchange water, and the mixture was heated to 75 ° C. in an argon atmosphere. A DMF solution in which 1.8 parts of 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 30 parts of DMF was added dropwise using a dropping funnel. Stirring was continued at 75 ° C. for 6 hours, followed by cooling to stop the polymerization.
Insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixed solution of tetrahydrofuran and hexane (volume ratio 40: 100). Next, after removing the solvent by an evaporator, it was vacuum dried at 60 ° C. to obtain 54 parts of resin.
When 1 part of this resin was dissolved in 100 parts of ion-exchanged water and titrated with 0.1NKOH methanol solution using thymolphthalein as an indicator, the acid value was 43 mgKOH. It was in good agreement with the value of 43 mg KOH calculated from the acid value of monomer 1-1 as copolymerized according to the charge ratio.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while neutralizing with an aqueous tetraethylammonium hydroxide solution. The viscosity of this solution measured at 25 ° C. was 2.5 mPa · s. The 10% by mass resin aqueous solution thus obtained was used for preparing a pigment dispersion.
From the titration result of the monomer raw material alendronic acid, it can be seen that three of the four OH groups of the phosphonic acid are neutralized when the color of thymolphthalein is discolored. Of the four OH groups, three are neutralized with tetraethylammonium ions.

[Synthesis Example 18 (Synthesis of Polymer 25) to Synthesis Example 36 (Synthesis of Polymer 43)]
As shown in Table 6, the mass% of the monomer (1) of the general formula (5), the mass% of the monomer (2) of the general formula (6), the general formulas (7a), (7b), and (7c) Polymers 25 to 43 were synthesized in the same manner as in Synthesis Example 17 except that the mass% of the represented monomer (3) was changed and synthesized under the reaction conditions shown in Table 7.
As the chain transfer agent, α-thioglycerol manufactured by Tokyo Chemical Industry Co., Ltd. was used.
Each of the obtained polymers 25 to 43 was neutralized to a salt composition (M in the general formula (1)) as shown in Table 6 or not used for preparation of a pigment dispersion as it was. Table 6 shows the viscosities at 25 ° C. of 10 mass% aqueous solutions of the respective polymers 25 to 43.

In Table 6, TetraEtA represents tetraethylammonium ion and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H, etc., M + represents 3 TetraEtA ions and 1 proton.
In Table 6, the abbreviations for the monomer (3) are shown below.
DMAM: N, N-dimethylacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
DMMAM: N, N-dimethylmethacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
HEAM: 2-hydroxyethylacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
DEAM: N, N-diethylacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
DAAM: Diacetone acrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Preparation example of pigment dispersion>
[Preparation of Pigment Dispersion 30]
After premixing the following mixture, it was circulated and dispersed for 10 minutes at a peripheral speed of 10 m / s with a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls with a diameter of 0.1 mm), and the pore size was 1 A pigment dispersion 30 was obtained by filtration through a 2 μm membrane filter.
Carbon black (NIPEX 160, manufactured by Degussa) ... 16.0 parts by mass A 10% by weight aqueous solution of polymer 17 ... 40.0 parts by weight Pure water ... 44.0 parts by weight

[Preparation of Pigment Dispersion 31 to Pigment Dispersion 54]
Similarly to the preparation of pigment dispersion 30, pigment dispersion 31 to pigment dispersion 54 were prepared according to the formulation (parts by mass) shown in Table 8.
In Table 8, the following products were used as pigments other than carbon black.
-Pigment Blue 15: 3 Chromo Fine Blue A-220JC, manufactured by Dainichi Seika Co., Ltd.- Pigment Red 122 Toner Magenta EO02, manufactured by Clariant, Inc.- Pigment Yellow 74 First Yellow 531, manufactured by Dainichi Seika Co., Ltd.

<Preparation of ink for ink jet recording>
[Example 23]
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter having a pore size of 1.2 μm to obtain an ink.
・ Pigment dispersion 30 (pigment solid content: 16% by mass): 40.0 parts by mass ・ Glycerin (water-soluble organic solvent): -10.0 parts by mass-1,3-butanediol (water-soluble organic solvent) ... 20.0 parts by mass-2-ethyl-1,3-hexanediol (water-soluble organic solvent)・ ・ ・ 1.0 part by mass ・ 2,2,4-trimethyl-1,3-pentanediol ・ ・ ・ 1.0 part by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
・ Distilled water ... 27.0 parts by mass

[Examples 24-47]
Using the same preparation method as in Example 1, inks of Examples 24-47 were prepared according to the formulations shown in Table 9.

[Example 48]
Using the same preparation method as in Example 17, the ink of Example 48 was prepared according to the formulation shown below.
・ Pigment dispersion 55 (pigment solid content: 16% by mass): 40.0 parts by mass Glycerin (water-soluble organic solvent): -10.0 parts by mass-1,3-butanediol (water-soluble organic solvent) ... 20.0 parts by mass-2-ethyl-1,3-hexanediol (water-soluble organic solvent)・ ・ ・ 1.0 part by mass ・ 2,2,4-trimethyl-1,3-pentanediol ・ ・ ・ 1.0 part by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
・ 10% by weight aqueous solution of polymer 1 ・ ・ ・ ・ ・ ・ 16.0 parts by weight ・ Distilled water ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... 11.0 parts by mass

[Evaluation results]
Next, each of the inkjet inks of Examples 23 to 48 was evaluated by the above evaluation method. The results are shown in Table 10 below.

From the results shown in Table 10, the inks of the examples having the configuration of the present invention are in practical areas where the image density, the stability of the dispersion, the storage stability of the ink, and the ejection recovery property are excellent. It can be seen that In particular, it can be seen that the storage stability and ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those in which the monomer content represented by the general formula (1) and the viscosity are controlled in a suitable range have particularly high evaluation results (Examples 23 to 30, 32 to 36, 39, and 40). 47) and the overall quality is improved. When the content and viscosity are out of the preferred ranges, the image density, storage stability, and ejection recovery performance are slightly reduced, but at a practicable level.
The ink of Example 48 using the polymer having a diphosphonic acid group of the present invention as an additive shows a slight decrease in quality as a whole compared with other examples using as a pigment dispersant, but it can be carried out. Is a level.

[Synthesis Example 37; Synthesis of Copolymer Polymer 44 Containing Phosphonic Acid Group]
In a reaction vessel equipped with a gas introduction tube, a thermometer, and a reflux condenser, 30 parts of monomer 2-1 and 6 parts of N- [3- (dimethylamino) propyl] acrylamide (manufactured by Tokyo Chemical Industry Co., Ltd., DMAPAA) And dissolved in 500 parts of N, N-dimethylformamide (DMF). Thereto was added an aqueous solution in which 24 parts of monomer 1-1 was dissolved in 100 parts of ion exchange water, and the mixture was heated to 75 ° C. in an argon atmosphere. A DMF solution in which 1.7 parts of 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 30 parts of DMF was added dropwise using a dropping funnel. Stirring was continued at 75 ° C. for 6 hours, followed by cooling to stop the polymerization.
Insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixed solution of tetrahydrofuran and hexane (volume ratio 40: 100). Next, the solvent was removed by an evaporator, and then vacuum dried at 60 ° C. to obtain 53 parts of resin.
When 1 part of this resin was dissolved in 100 parts of ion-exchanged water and titrated with 0.1NKOH methanol solution using thymolphthalein as an indicator, the acid value was 43 mgKOH. It was in good agreement with the value of 43 mg KOH calculated from the acid value of monomer 1-1 as copolymerized according to the charge ratio.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while neutralizing with an aqueous tetraethylammonium hydroxide solution. When the viscosity of this solution was measured at 25 ° C., it was 2.4 mPa · s. The 10% by mass resin aqueous solution thus obtained was used for preparing a pigment dispersion.
From the titration result of the monomer raw material alendronic acid, it can be seen that three of the four OH groups of the phosphonic acid are neutralized when the color of thymolphthalein is discolored. Of the four OH groups, three are neutralized with tetraethylammonium ions.

[Synthesis Example 38 (Synthesis of Polymer 45) to Synthesis Example 56 (Synthesis of Polymer 63)]
As shown in Table 11, mass% of the monomer (1) of the general formula (5), mass% of the monomer (2) of the general formula (6), monomers represented by the general formulas (8a) and (8b) Polymers 45 to 63 were synthesized in the same manner as in Synthesis Example 1 except that the mass% of (4) was changed and synthesis was performed under the reaction conditions shown in Table 12.
As the chain transfer agent, α-thioglycerol manufactured by Tokyo Chemical Industry Co., Ltd. was used.
Each of the obtained polymers 45 to 63 was neutralized to a salt composition (M in the general formula (1)) as shown in Table 11 or not used for preparation of a pigment dispersion as it was. Table 11 shows the viscosity of 10% by mass aqueous solution of each of the polymers 44 to 63.

In Table 11, TetraEtA represents tetraethylammonium ion and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H, etc., M + represents 3 TetraEtA ions and 1 proton.
In Table 11, the abbreviations of the monomer (4a) or (4b) of the general formula (7a) or (7b) are shown below.
DMAPAA: N- [3- (dimethylamino) propyl] acrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
DEAEAA: N- [2- (diethylamino) ethyl] acrylamide (synthesized by a conventionally known method)
TMMEAC: trimethyl-2-methacryloyloxyethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., 80% aqueous solution)

<Preparation example of pigment dispersion>
[Preparation of Pigment Dispersion 55]
After premixing the following mixture, it was circulated and dispersed for 10 minutes at a peripheral speed of 10 m / s with a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls with a diameter of 0.1 mm), and the pore size was 1 A pigment dispersion 55 was obtained by filtration through a 2 μm membrane filter.
-Carbon black (NIPEX 160, manufactured by Degussa)-16.0 parts by weight-10% by weight aqueous solution of polymer 1-40.0 parts by weight-Pure water-44.0 parts by weight

[Preparation of pigment dispersion 56 to pigment dispersion 80]
In the same manner as in Pigment Dispersion Preparation Example 55, Pigment Dispersion 56 to Pigment Dispersion 80 were prepared according to the formulation shown in Table 13.
In Table 13, the following products were used as pigments other than carbon black.
-Pigment Blue 15: 3 Chromo Fine Blue A-220JC, manufactured by Dainichi Seika Co., Ltd.- Pigment Red 122 Toner Magenta EO02, manufactured by Clariant, Inc.- Pigment Yellow 74 First Yellow 531, manufactured by Dainichi Seika Co., Ltd.

<Preparation of ink for ink jet recording>
[Example 49]
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter having a pore size of 1.2 μm to obtain an ink.
・ Pigment dispersion 44 (pigment solid content: 16% by mass): 40.0 parts by mass ・ Glycerin (water-soluble organic solvent): -10.0 parts by mass-1,3-butanediol (water-soluble organic solvent) ... 20.0 parts by mass-2-ethyl-1,3-hexanediol (water-soluble organic solvent)・ ・ ・ 1.0 part by mass ・ 2,2,4-trimethyl-1,3-pentanediol ・ ・ ・ 1.0 part by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
-Distilled water ... 27.0 parts by mass [Examples 50 to 73]
Using the same preparation method as in Example 49, inks of Examples 50 to 73 were prepared according to the formulations shown in Table 14.

[Example 74]
Using the same preparation method as in Example 1, the ink of Example 74 was prepared according to the formulation shown below.
・ Pigment dispersion 80 (pigment solid content 16% by mass) ・ ・ ・ ・ ・ ・ 40.0 parts by mass ・ Glycerin (water-soluble organic solvent) ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ 10.0 mass parts ・ 1,3-butanediol (water-soluble organic solvent) ・ ・ ・ 20.0 mass parts ・ 2-ethyl-1,3-hexanediol (water-soluble) Organic solvent) ··· 1.0 parts by mass · 2,2,4-trimethyl-1,3-pentanediol ··· 1.0 parts by mass (water-soluble organic solvent)
・ Fluorosurfactant ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.0 parts by mass (100% solids, manufactured by Daikin Industries, Unidyne DSN-403N)
-10% by weight aqueous solution of polymer 44 ... 16.0 parts by weight-Distilled water ... ... 11.0 parts by mass

[Evaluation results]
Next, the tests for <image density>, <storability of pigment dispersion>, <storage stability of ink>, and <ejection recovery property> described above were performed, and each of the inkjet inks of Examples 49 to 74 was evaluated. did. The evaluation criteria for each test are the same as above. The results are shown in Table 15 below.
In the <Ink Storage Stability> test, Table 15 shows the 60 ° C. 1 week storage evaluation result as “ink storage stability 1” and the 70 ° C. 2 week storage evaluation result as “ink storage stability 2”. .

From the results shown in Table 15, the inks of the examples having the configuration of the present invention are in practical areas where the image density, the dispersion stability, the ink storage stability, and the ejection recovery property are both practical and excellent in practicality. It can be seen that In particular, it can be seen that the storage stability and ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those in which the monomer content represented by the general formula (1) and the viscosity are controlled within a suitable range have particularly high evaluation results (Examples 49 to 56, 58 to 62, 65 and 66). 73) and the overall quality is improved. When the content and viscosity are out of the preferred ranges, the image density, storage stability, and ejection recovery performance are slightly reduced, but at a practicable level.
The ink of Example 74 using the polymer having a diphosphonic acid group of the present invention as an additive shows a slight deterioration in quality as a whole as compared with the other examples using as a pigment dispersant. Is a level.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 4 Front surface 5 Upper surface 6 Cartridge loading part 7 Operation part 8 Front cover 10 Ink cartridge 21 Frame 21A Side plate 21B Side plate 21C Rear plate 22 Flexible cable 23 Supply pump unit 25 Main body side holder 26 Fixed Rib 31 Guide rod 32 Stay 33 Carriage 34 Recording head 35 Sub tank 36 Ink supply tube 37 Ink supply tube 41 Paper stacking portion (bottom plate)
42 paper 43 half moon roller (paper roller)
44 Separating Pad 45 Guide 51 Conveying Belt 52 Counter Roller 53 Conveying Guide 54 Pressing Member 55 Tip Pressure Roller 56 Charging Roller 57 Conveying Roller 58 Tension Roller 61 Guide Member 71 Separating Claw 72 Paper Discharge Roller 73 Paper Discharge Roller 81 Double-sided Paper Feed Unit 82 Manual Feeding Section 91 Subsystem 92 Cap 92a Cap 92b Cap 92c Cap 92d Cap 93 Wiper Blade 94 Empty Discharge Receiver 95 Wiper Cleaner 96 Cleaner Roll 98 Empty Discharge Receiver 99 Opening 111 Maintenance Device Frame 112A Cap Holder 112B Cap Holder 115 Carriage Lock 117 Carriage lock arm 118 Wiper liner 119 Flexible tube 120 Tubing pump (suction pump)
120a pump shaft 121 cam shaft 122A cap cam 122B cap cam 124 wiper cam 125 carriage lock cam 126 roller 128 cleaner cam 131 motor 131a motor shaft 132 motor gear 133 pump gear 134 intermediate gear 135 intermediate gear 136 intermediate gear 137 clutch gear 138 intermediate gear 140 139 Cam gear 141 Intermediate shaft 142 Home position sensor cam 150a Guide pin 150b Guide shaft 151 Holder 152 Spring 153 Slider 154 Guide pin 155 Guide pin 156 Guide groove 157 Cam pin

Special table 2009-513802 JP 2014-114409 A EP2843013A1 JP 2012-51357 A JP 2004-123904 A

Claims (14)

An ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is a tetra It is an alkyl ammonium salt, and the polymer has at least the structural unit (1) represented by the general formula (1) and the structural unit (2) represented by the general formula (2). Ink characterized by.

(R ₁ in the general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in the general formula (2) represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.) An ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is a tetra And an alkylammonium salt, and the polymer has a structural unit (1) represented by the general formula (1), a structural unit (2) represented by the general formula (2), a general formula (3a), An ink comprising at least the structural unit (3) represented by the general formula (3b) or the general formula (3c).

(R ₁ in the general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in the general formula (2) represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.)

(R ₃ in the general formula (3a) represents a hydrogen atom or a methyl group.)

(R ₄ in the general formula (3b) represents a hydrogen atom or a methyl group, and R ₅ and R ₆ each independently represents a methyl group or an ethyl group.)

(R ₇ in the general formula (3c) represents a hydrogen atom or a methyl group, and Y ₁ represents a methylene group or an ethylene group.) An ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is a tetra And an alkylammonium salt, and the polymer has a structural unit (1) represented by the general formula (1), a structural unit (2) represented by the general formula (2), a general formula (4a) An ink comprising at least the structural unit (4) represented by the general formula (4b).

(R ₁ in the general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in the general formula (2) represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.)

(R ₈ in the general formula (4a) represents a hydrogen atom or a methyl group, R ₉ and R ₁₀ represent a methyl group or an ethyl group, and Y ₂ represents an alkylene group having 1 to 4 carbon atoms.)

(R ₁₁ in the general formula (4b) represents a hydrogen atom or a methyl group, and Y ₃ represents an alkylene group having 1 to ₃ carbon atoms.)   The ink according to any one of claims 1 to 3, wherein L in the structural unit of the general formula (2) is an alkylene group having 2 to 12 carbon atoms.   The ink according to any one of claims 1 to 4, wherein the content of the structural unit (1) in the polymer is 20% by mass to 60% by mass.   The ink according to any one of claims 1 to 5, wherein the content of the structural unit (1) in the polymer is 30% by mass to 50% by mass.   The ink according to claim 6, wherein the polymer has an aqueous solution viscosity (concentration of 10 mass%, 25 ° C.) of 1.5 to 4.0 mPa · s. An aqueous ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is A tetraalkylammonium salt, and the polymer is obtained by radical polymerization of a polymerizable material containing at least the monomer (1) represented by the general formula (5) and the monomer (2) represented by the general formula (6). An ink characterized by being synthesized.

(In the general formula (5), R ₁ represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(In General Formula (6), R ₂ represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.) An aqueous ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is A tetraalkylammonium salt, and the polymer is a monomer (1) represented by the general formula (5), a monomer (2) represented by the general formula (6), and the general formulas (7a) and (7b). Or an ink synthesized by radical polymerization of a polymerizable material containing at least the monomer (3a), (3b) or (3c) represented by (7c).

(In the general formula (5), R ₁ represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(In General Formula (6), R ₂ represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.)

(In the general formula (7a), R ₃ represents a hydrogen atom or a methyl group.)

(In General Formula (7b), R ₄ represents a hydrogen atom or a methyl group, and R ₅ and R ₆ each independently represent a methyl group or an ethyl group.)

(In the general formula (7c), R ₇ represents a hydrogen atom or a methyl group, and Y ₁ represents a methylene group or an ethylene group). An aqueous ink comprising at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer is a copolymer having a diphosphonic acid group, and at least a part of the diphosphonic acid group is A tetraalkylammonium salt, and the polymer is a monomer (1) represented by the general formula (5), a monomer (2) represented by the general formula (6), and a general formula (8a) or (8b). An ink synthesized by radical polymerization of a polymerizable material containing at least the monomer (4a) or (4b) represented by

(In the general formula (5), R ₁ represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(In General Formula (6), R ₂ represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.)

(R ₈ in the general formula (8a) represents a hydrogen atom or a methyl group, R ₉ and R ₁₀ represent a methyl group or an ethyl group, and Y ₂ represents an alkylene group having 1 to 4 carbon atoms.)

(R ₁₁ in the general formula (8b) represents a hydrogen atom or a methyl group, and Y ₃ represents an alkylene group having 1 to ₃ carbon atoms.)   An ink cartridge comprising the ink according to claim 1 contained in a container.   An ink jet recording apparatus comprising at least ink flying means for recording an image by flying the ink according to claim 1.   An ink jet recording method comprising at least an ink flying step of recording an image by flying the ink according to claim 1.   An ink recorded matter comprising an image recorded with the ink according to any one of claims 1 to 10 on a recording medium.

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