JP6507868B2 - Ink, ink cartridge, ink jet recording apparatus, ink jet recording method and ink recorded matter - Google Patents

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 an advantage that the process is simple compared with other recording methods, and full-coloring is easy, and a high-resolution image can be obtained even with an apparatus having a simple configuration. It has been done. In this inkjet recording method, a small amount of ink is ejected by bubbles generated by heat, pressure generated by using piezo or electrostatic, etc., and the ink is adhered to a recording medium such as paper and dried quickly (or recording By permeating the medium, it is an image forming method, and the application to personal and industrial printers and printing has been expanded.

In such an inkjet recording system, an aqueous ink (dye ink) using a water-soluble dye as a coloring agent is mainly used, but the dye ink has a disadvantage that it is inferior in weather resistance and water resistance. For this reason, research is being conducted on pigment inks that use water-insoluble pigments instead of water-soluble dyes. However, the pigment ink is still inferior to the dye ink in color developability and storage stability of the ink.
In addition, pigment ink is inferior in discharge stability to dye ink. For example, when the water evaporates at the tip of the ink head nozzle, the concentration of the water-soluble solvent becomes high, the pigment and the ink composition are easily deposited, and the ink is bent or missing, causing cleaning of the ink head nozzle, etc. It requires an ejection recovery operation.
Further, with the improvement of the image quality improvement technology of the OA printer, a high image density is required even if plain paper is used as a recording medium in the pigment ink. However, when plain paper is used as a recording medium, the pigment ink has a problem that the pigment concentration on the paper surface is lowered by penetration into the paper, and the image density is lowered.

Further, in recent years, the demand particularly for industrial use has increased, and high speed printing has been desired. Along with such high speed printing, an ink jet printer equipped with a line head has also been proposed. In order to speed up the drying of the ink adhering to the recording medium in order to achieve high-speed printing, it is attempted to accelerate the drying by adding a penetrant to the ink and permeating the water into the recording medium. Not only that, but also the permeability of the pigment to the recording medium becomes high, and there is a problem that the image density is lowered.
When plain paper is used as the recording medium, the surface of the plain paper is swelled by water as a solvent of ink immediately after printing, and there is a problem that the difference in elongation rate between the front and back becomes large and curling occurs. Such a phenomenon is not a problem in low speed printing because it is eliminated as the drying progresses.
However, as printing becomes faster, it is necessary to transport the recording medium without curling being eliminated, which may cause a paper jam. With regard to curling, a means for increasing the content of the organic solvent in the ink is effective, but since the ink becomes more hydrophobic, it becomes difficult to secure the storage stability and the ejection stability of the ink.

  In order to solve the above problems, for example, an inkjet 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 the diphosphonic acid group of the polymer and the paper when the colorant comes in contact with the paper. It is believed that it can be destabilized with the Ca salt in the medium to improve the printed image. However, there is a problem that the storage property of the ink and the ejection recovery property are low.

  Also, an ink jet recording ink 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 which constitutes the above-mentioned polymer, and when the colorant comes in contact with the paper, the diphosphonic acid group of the polymer and Ca in the paper It is believed that it can be destabilized with salt and improve the printed image. In addition, using this polymer as a pigment dispersant ensures an ink storability of 1 week at 60 ° C., but it is still insufficient in terms of storage stability. In addition, when continuous printing is performed at high speed, there is a problem that the ink discharge characteristics from the nozzles become unstable, and there is a problem that discharge recovery is low.

  Similarly, an ink jet recording ink 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 salt of 4-methacrylamide-1-hydroxybutane-1,1-diphosphonic acid and a specific monomer such as a hydrocarbon-based acrylic acid ester are used as monomers constituting the polymer, and high image density on plain paper is obtained. Both ink storage stability and ink storage performance are achieved, and by using this polymer as a pigment dispersant, the ink storage performance at 60 ° C. for one week is secured, but it is still insufficient in terms of storage stability. Similarly, when printing is continuously performed at high speed, there is a problem that the ink ejection characteristics from the nozzles become unstable, and there is a problem that the ejection recovery property 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 an ink containing a pigment having a phosphorus-containing group bonded thereto, a resin emulsion, and a surfactant is printed (see Patent Document 4). In this proposal, it is described that bisphosphonic acid is preferable as the phosphorus-containing group, and it is described that the Ca salt of the receiving liquid reacts with the phosphorus-containing group to have an effect of improving feathering and fixing property. There is. However, in the proposed technique, the phosphonic acid group-containing polymer is not used as a dispersant for the pigment dispersion and as an additive, but a pigment bonded with phosphoric acid is used, and the image when recorded on plain paper The effect of improving the concentration is not sufficient. In addition, in the case of this method, since it is necessary to chemically modify the surface of the pigment in advance, there is a problem that versatility in pigment selection is low.

In addition, an aqueous ink comprising a colorant, water, a water-soluble organic solvent, a surfactant, and a chelating agent has been proposed (see Patent Document 5). In this proposal, a low molecular weight compound, hydroxyethylidene diphosphonic acid or a salt thereof is used as the chelating agent. The chelating agent is said to be capable of removing calcium and the like contained in the dispersion of the pigment and the like to improve the ejection stability and the storage stability. However, only the low molecular weight compound, hydroxyethylidene diphosphonic acid, is described in the above proposal, and there is no description about polymers containing phosphonic acid, and the image density is improved when recorded on a chelating agent and plain paper. There is also no mention of the relationship with effects.
Therefore, it is desired to provide an ink jet recording ink which can obtain high image density even when printed on plain paper and is excellent in storage stability and ejection recovery even when the content of the water-soluble organic solvent is increased.

An object of the present invention is to solve the above-mentioned problems in the prior art and to achieve the following objects.
That is, an object of the present invention is to provide an ink which can obtain high image density and is excellent in storage stability and ejection recovery property.

  The ink of the present invention as a means for solving the above problems is an ink containing at least water, a water-soluble solvent, a pigment, and a polymer having a phosphonic acid group, wherein the polymer has a diphosphonic acid group A copolymer, at least a portion of the diphosphonic acid group is a tetraalkyl ammonium 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 general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in 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, a high image density can be obtained, and an ink excellent in storage stability and ejection recovery can be provided.

It is the schematic plan view seen from the nozzle surface which shows an example (2 head types) 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 types) of the recording head arrange | positioned at the inkjet recording device of this invention. FIG. 2 is a perspective explanatory view seen from the front side showing an example of the ink jet printing apparatus of the present invention having a maintenance and recovery device. FIG. 6 is a schematic configuration view for explaining the overall configuration of a mechanical unit of the inkjet recording apparatus shown in FIG. 3; FIG. 4 is an explanatory plan view of an essential part of a mechanical part of the ink jet recording apparatus shown in FIG. 3; FIG. 6 is a plan view of relevant parts of a subsystem including a maintenance and recovery device in the ink jet printing apparatus of the present invention. It is a schematic schematic block diagram of the subsystem shown in FIG. It is right side explanatory drawing of the subsystem shown in FIG. It is side explanatory drawing of the holding raising / lowering mechanism part of a cap.

  Detailed Description of the Invention The present invention will be described in detail below, but the present invention includes the ink of the embodiment as 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 a polymer or copolymer) is represented by the structural unit (1) represented by the general formula (1) and the general formula (2) It is a copolymer which has a structural unit (2) represented at least.

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

(R ₃ in General Formula (3a) represents a hydrogen atom or a methyl group.)

(R ₄ in General Formula (3b) represents a hydrogen atom or a methyl group, and R ₅ and R ₆ each independently represent 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 copolymer) is a structural unit (1) represented by the general formula (1), It is a copolymer which has a structural unit (2) represented by Formula (2), and a structural unit (4) represented by following General formula (4a) or General formula (4b).

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

(R ₁₁ in 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 tetraalkyl ammonium ion of M ^{+ in} the general formula (1) is an ammonium ion having four alkyl groups having 1 to 22 carbon atoms, and examples thereof include tetramethyl ammonium ion, tetraethyl ammonium ion and tetrapropyl ammonium ion, Examples thereof include tetrabutyl ammonium ion, tetraamyl ammonium ion, benzyl trimethyl ammonium ion, hydroxyethyl trimethyl ammonium ion, methyl trioctyl ammonium ion, trimethyl stearyl ammonium ion and the like. In particular, the use of a tetraalkylammonium ion consisting of an alkyl group having 1 to 5 carbon atoms is particularly preferable because it can provide an ink having a low viscosity and excellent storage stability.
As a tetraalkyl ammonium ion consisting of an alkyl group having 1 to 5 carbon atoms, for example, tetraethyl ammonium ion, tetrabutyl ammonium ion, methyl tributyl ammonium ion, methyl triamyl ammonium ion, triethyl methyl ammonium ion, etc. It can be mentioned.
It is preferable that two or three of the M ⁺ be tetraalkyl ammonium ions, and the rest be hydrogen ions (protons).

Moreover, as a C2-C18 alkylene group represented by L in General formula (2), an ethylene group, a propylene group, a butylene group, a hexylene group, a nonylene group, a dodecylene group, a stearylene group etc. may be mentioned. it can. Moreover, Preferably it is a C2-C16 alkylene group, More preferably, it is a C2-C12 alkylene group.
Since the naphthyl group present at the end via L has excellent pigment adsorption power due to π-π stacking with the pigment which is a coloring material in the aqueous ink (hereinafter sometimes referred to as ink), the ink is preserved Stability can be improved.

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

The copolymer having a diphosphonic acid group used in the present invention can be produced by the method for producing a polymer 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 is widely used in various fields. Can.
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 is not particularly limited, and can be widely used in various fields.
Also in the case of a copolymer including the structural unit (4) represented by the general formula (4a) or the general formula (4b) instead of the structural unit (3) together with the structural units (1) and (2) It is.
For example, it can be suitably used as a pigment dispersant, a pigment concentration improver, a pigment binder resin, a viscosity modifier, etc. in an ink jet recording ink.

<Method of producing polymer>
The polymer used in the present invention was obtained by radically polymerizing 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) After that, the resultant polymer can be further synthesized by neutralization adjustment with a tetraalkylammonium base.
The polymer used in the present invention is 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) After radical polymerization of the polymerizable material containing at least the monomer (3a), (3b) or (3c) represented by (7c) or (7c), the obtained polymer is further neutralized and adjusted with a tetraalkylammonium base Can be synthesized by
Furthermore, the polymer used in the present invention is 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) After radical polymerization of the polymerizable material containing at least the monomer (4a) or (4b) represented by 8b), the polymer obtained can be further synthesized by neutralization adjustment with a tetraalkylammonium base .

  Neutralization adjustment is a neutralization treatment which is carried out in the case of further neutralization in addition to the tetraalkyl ammonium salt which has already been neutralized in the monomer stage, and is the same or different compound as the ammonium ion attached in the monomer stage. Neutralization adjustment can be performed by using. The total amount of neutralization can be adjusted to an amount of 1 to 4 of the four acid groups in the general formula (1), but preferably 2 or 3 tetraalkylammonium ions per molecule of monomer. .

  Specific examples of the monomer (1) represented by the general formula (5) include methacrylamidomethylenediphosphonic acid, acrylamidomethylenediphosphonic acid and their disodium salts, trisodium salts, dipotassium salts and tripotassium salts, 2 tetramethyl ammonium salt, 3 tetramethyl ammonium salt, 2 tetra ethyl ammonium salt, 3 tetra ethyl ammonium salt, 2 tetra propyl ammonium salt, 3 tetra propyl ammonium salt, 2 tetra butyl ammonium salt, 3 tetra butyl ammonium salt and the like. Furthermore, the case where multiple types of tetraalkyl ammonium ion are mixed can be mentioned.

As a synthesis method of the monomer (1) represented by the above general formula (5), a method of synthesizing by 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 a demethylation reaction is mentioned.
In the former case, aminomethylene diphosphonic acid is preferably subjected to neutralization treatment in advance, and then it is preferably synthesized by esterification reaction with acid chloride, and after the reaction, the number of salts can be adjusted by reverse neutralization treatment. In the latter case, the diphosphonate is obtained and then neutralized to adjust the number of salts.

In the said General formula (6), as a C2-C18 alkylene group represented by L, it is the same as that of the case of General formula (2). The bonding position of the naphthyl group may be either α or β.
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) and (2), first, naphthalene carbonyl chloride (A-1) and an excess amount of diol compound are subjected to a condensation reaction in the presence of an acid acceptor such as amine or pyridine Thus, naphthalenecarboxylic acid hydroxyalkyl ester (A-2) is obtained. Next, 2-methacryloyloxyethyl isocyanate (A-3) and the above (A-2) can be reacted to obtain a monomer (2).

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).
As a monomer (3c) represented by the said General formula (7c), N- (hydroxymethyl) (meth) acrylamide and N- (2- hydroxyethyl) (meth) acrylamide are mentioned.
Further, 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.
As the monomer (4a) represented by the general formula (8a), 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 etc Be
In addition, as the monomer (4b) represented by the general formula (8b), trimethyl (meth) acryloyloxymethyl ammonium chloride, trimethyl-2- (meth) acryloyloxyethyl ammonium chloride, trimethyl-3- (meth) acryloyl An oxypropyl ammonium chloride etc. are mentioned.
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 using the monomer (1) and the monomer (2) obtained as described above It is polymerized by a known polymerization method such as bulk polymerization method, solution polymerization method, suspension polymerization method, emulsion polymerization method and the like.
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 obtained as described above 1) Well-known methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization using monomer (2) and monomer (3) (= monomer (3a), (3b) or (3c)) It is polymerized by the 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) Well-known methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization using monomer (2) and monomer (4) (= monomer (4a), (4b) or (4c)) It is polymerized by the polymerization method.

Although not limited to these polymerization methods, a method using a radical polymerization initiator is preferable because polymerization operation and adjustment of molecular weight are easy, and a solution polymerization method in which polymerization is performed in a mixed solvent of an organic solvent and water is more preferable.
There is no particular limitation on the operation when performing radical polymerization in the solution polymerization method, but the monomer, initiator, chain transfer agent, and solvent may be charged at once in the polymerization reaction vessel, or continuously using a dropping funnel. It may be supplied as In addition, if necessary, an initiator may be added during the polymerization reaction.

As the solvent for radical polymerization in the solution polymerization method, a mixed solvent of water and a water-soluble organic solvent is preferable because the monomer (1) is water-soluble and the monomer (2) is water-insoluble. As the water-soluble organic solvent, alcohol solvents such as methanol, ethanol, 2-methoxyethanol and 2-ethoxyethanol, ether solvents such as tetrahydrofuran, and amide solvents such as N, N-dimethylformamide can be used, and the monomers can be used. There is no particular limitation as long as it dissolves.
In addition to using the mixed solvent from the beginning, the aqueous solution of the monomer (1) and the organic solvent liquid of the monomer (2) may be mixed at the time of polymerization.
It is important for the solubility of the monomer (1) and the monomer (2) to be close to each other in order to increase the copolymerizability, and in the present invention, by making the monomer (1) into a tetraalkylammonium salt, the monomer (2) and The copolymer has been successfully synthesized by making the solubility difference between If a sodium salt similar to monomer (1) is used, the synthesis of a copolymer resin with monomer (2) becomes difficult.
Focusing only on solubility, the longer the alkyl group in tetraalkylammonium, the stronger the hydrophobicity, and it is predicted that the copolymerizability with monomer (2) will be excellent, but it is selected in balance with other properties .
The monomer (3) may be dissolved in the mixed solvent from the beginning, or may be dissolved in the 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, peroxy ketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxy dicarbonate, peroxy ester, cyano 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.
There is no restriction | limiting in particular, content of the said polymerization initiator can be suitably selected according to the objective, However, 1 mass%-20 mass% are preferable with respect to the total mass of a polymerizable monomer.

An appropriate amount of chain transfer agent may be added to adjust the molecular weight of the polymer. Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, nonyl mercaptan, 1-dodecanethiol, thioglycerol and the like.
The polymerization temperature is not particularly limited and may be appropriately selected depending on the purpose, but 50 ° C to 150 ° C is preferable, and 60 ° C to 100 ° C is more preferable. The polymerization time is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 3 hours to 48 hours.

The resulting polymer is neutralized with tetraalkyl ammonium base.
The neutralization treatment can be carried out by neutralizing a part or all of the phosphonic acid groups of the polymer with a tetraalkylammonium base.
When all the neutralization is 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. After polymerization, the remaining acid groups are neutralized.
In addition, it is also possible to perform the neutralization process of the said tetraalkyl ammonium base in the state which mixed the pigment and the polymer in the manufacturing process of ink.

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, a condenser, the general formula An organic solvent solution in which monomer (2) of (6) is dissolved, and a solution in which a polymerization initiator, a molecular weight modifier, and the like are dissolved are batchwise or continuously charged under inert gas with stirring at 60 ° C to 150 ° C. The reaction can be carried out at a temperature of 50 ° C., followed by neutralization treatment 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 a polymerization initiator, a molecular weight modifier, etc. are dissolved under inert gas The reaction can be carried out by batchwise or continuously charging, reacting at a temperature of 60 ° C. to 150 ° C., and then performing neutralization treatment with a tetraalkyl ammonium 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 (4) of the general formula (8a) or (8b) are dissolved, and a solution in which a polymerization initiator, a molecular weight modifier, etc. are dissolved are batched or continuous under inert gas. The reaction can be carried out by adding and stirring, reacting at a temperature of 60 ° C. to 150 ° C., and then performing neutralization treatment with a tetraalkyl ammonium base.

At the time of neutralization, the degree of neutralization can be controlled by measuring the acid value of the resin in advance and performing neutralization treatment accordingly. The acid value can be determined by dissolving or dispersing the weighed resin in water or a water-soluble organic solvent or a mixed solvent thereof, and performing neutralization titration with potassium hydroxide methanol solution having a specified concentration using thymolphthalein as an indicator.
It is known that, of the diphosphonic acid groups of the polymer in the present invention, three of four acid groups are neutralized at the time of discoloration of thymolphthalein (pH = 8 to 9). Therefore, when acid value is determined using thymolphthalein as an indicator, and a base is added and neutralized accordingly, it is possible to adjust a structure in which three acid groups are neutralized.

  20-60 mass% is preferable, and, as for the ratio in the whole monomer of the monomer (1) of the said General formula (5) at the time of a synthesis | combination, 30-50 mass% is more preferable.

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, which is difficult to measure by adsorption onto a GPC column.
Therefore, in the present invention, the viscosity when the polymer is made into a solution of a certain concentration is taken as the substitute characteristic of the molecular weight. The viscosity can be measured as follows. Using a viscometer (RE500L, manufactured by Toki Sangyo Co., Ltd.), the viscosity is adjusted to 50 revolutions or 100 revolutions in accordance with the viscosity of the sample and measurement is performed.
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 further preferably 1.7 mPa · s to 3.0 mPa · s. preferable.
When the aqueous solution viscosity of the polymer is 1.5 mPa · s or more, the decrease in the image density due to the decrease in the calcium reactivity hardly occurs, and when the viscosity is 4.0 mPa · s or less, the pigment resulting from the decrease in the dispersion stability The storage stability of the dispersion and ink is less likely to occur.
When the viscosity is in the range of 1.7 mPa · s to 3.0 mPa · s, the decrease in the image density and the deterioration in the ink storage stability become even more difficult to occur. In addition, the deterioration of the storage stability of the ink may lead to the deterioration of the ejection recovery property.

The molecular weight of the polymer in the present invention can be controlled to some extent by the polymerization temperature, the amount of polymerization initiator, and the monomer concentration at the time of reaction.
With regard to the polymerization temperature, a low molecular weight polymer is easily obtained when the polymerization is performed in a short time at high temperature, and a high molecular weight polymer tends to be easily obtained when the polymerization is performed at a low temperature for a long time.
With regard to the content of the polymerization initiator, the larger the amount, the lower the molecular weight polymer tends to be obtained, and the smaller the amount tends to result in a higher molecular weight polymer.
With regard to the monomer concentration at the time of the reaction, it is easy to obtain a high molecular weight polymer at a high concentration, and a low molecular weight polymer tends to be easily obtained at a low concentration.
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, the chain transfer agent receives radicals from the grown polymer chain and stops the polymer elongation, but since the chain transfer agent receiving the radical can attack the monomer and start the polymerization again, It also contributes to control of molecular weight distribution and control of 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 needed.

<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 above general formula (1) has higher water solubility than conventionally used alondronate methacrylamides and the like having a diphosphonic acid structure, and when the copolymerization composition of the present invention is influenced by that, The hydrophobic interaction of the hydrophobic group with the pigment intensifies, and the dispersion stability of the pigment is increased.
In addition, the structural unit derived from 1-methacryloxyethane-1,1-diphosphonic acid which has been used in the prior art is insufficient in storage stability and discharge recovery, probably because of a problem with hydrolysis resistance. On the other hand, the diphosphonic acid structure of the present invention is resistant to hydrolysis, and is advantageous in storage stability and discharge stability.
As shown in the structural unit represented by the general formula (1), by setting the diphosphonic acid group-containing structural unit to acrylamide in which the tetraalkyl ammonium salt is used, the hydrophobicity of the diphosphonic acid group-containing structural unit is increased. The 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 adsorptivity by π-π stacking with a pigment because a naphthyl group is present at the end 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 high image density due to the multivalent ion aggregation function of the diphosphonic acid group can be obtained. It can exhibit excellent storage stability.
In addition, by having excellent pigment adsorptivity, when water is evaporated at the tip of the ink head nozzle, the copolymer resin is difficult to be detached from the pigment even in an environment where the concentration of the water-soluble organic solvent is high, and the pigment Precipitation due to dispersion instability can be prevented.
Furthermore, by increasing the hydrophobicity of the copolymer resin, 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 increased, and precipitation of the copolymer resin at the tip of the ink head nozzle can be achieved. It can prevent.
That is, by using the copolymer resin containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2), the pigment and the copolymer resin are precipitated at the tip of the ink head nozzle. It is possible to suppress an ejection failure resulting from the ejection performance recovery operation such as head cleaning.
Further, 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 it has a high affinity for a water-soluble solvent. In which the structural unit (3) represented by the general formula (3a), the general formula (3b) or the general formula (3c) is further copolymerized with the structural unit represented by the general formula (2) and the structural unit represented by the general formula (2) By using the copolymer of (1), the affinity of the copolymer resin to the water-soluble solvent can be increased, and the storage stability of the ink and the ejection recovery can be further improved.
Furthermore, the structural unit (4a) represented by the above general formula (4a) belonging to the structural unit (4) is basic having a tertiary amine structure and is based on acid group interaction with an acid group present on the pigment surface It exerts a bonding power and works to compensate for the reduction of the pigment adsorption of the resin by weakening the hydrophobic interaction between the hydrophobic group and the pigment by the water-soluble solvent entering the ink vehicle. Thereby, good dispersibility and storage stability can be improved even in the ink containing the water-soluble solvent. For example, many carbon black surfaces to be black pigments have carboxyl groups present, in which case a tertiary amino group portion showing basicity of the structural portion represented by the general formula (4a) and acid-base interaction Strongly adsorb.
In addition, the structural unit (4b) represented by the general formula (4b) belonging to the structural unit (4) has a quaternary ammonium base, and has a bonding strength due to acid group interaction with an acid group present on the pigment surface. Demonstrate. As a result, the water-soluble solvent enters the ink vehicle, weakens the hydrophobic interaction between the hydrophobic group and the pigment, and functions 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 to be black pigments have carboxyl groups, and they are strongly adsorbed by acid-base interactions with the quaternary ammonium base of the structural unit represented by the general formula (4b).
Although the reason is not clear, structural unit (1) represented by the general formula (1), 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), it has the function of preventing the association of phosphonic acid group in the polymer, and the effect of further improving the storage stability in water-based ink . The expression of these functions can further improve the storage stability and the ejection recovery of the ink.

  Therefore, when the polymer according to the present invention is used for an ink jet recording ink, the ink exhibits good dispersion stability and storage stability. Furthermore, when the ink is printed on paper, even if it is a plain paper with a low content of Ca ions, the polymer in the present invention is made hydrophobic by the Ca ions eluting from the paper to the ink, and the above general formula ( Since the structural unit represented by 2) has high adsorptivity to the pigment, the pigment can be retained on the paper surface by incorporating and aggregating the pigment, and a higher image density can be realized.

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, in solid content, 0.05% by mass to 10% by mass is preferable, 0.5% by mass to 5% by mass is more preferable, and 1% by mass to 3% by mass is particularly preferable.
When the content is 0.05% by mass or more, the improvement effect of the image density is recognized, and when it is 10% by mass or less, it is possible to set the viscosity range suitable for discharging the ink from the head.

  The polymer in the present invention is not particularly limited, and can be used as a pigment dispersant or an additive to a pigment dispersion. If it is used as a pigment dispersant, further improvement in storage stability and discharge stability in an image having an image density on plain paper and an ink containing a large amount of water-soluble organic solvent can be observed.

  When used as a pigment dispersant, the content of the polymer in the present invention is not particularly limited, and can be appropriately selected depending on the purpose. And 1 mass part-100 mass parts are preferred to 100 mass parts of the above-mentioned pigments, 5 mass parts-80 mass parts are more preferred, and 10 mass parts-50 mass parts are still more preferred. When the content is in the above-mentioned preferable range, a high image density can be obtained, which is advantageous in that the dispersion stability and the storage stability become good.

<Water>
As the water, for example, pure water such as ion exchange water, ultrafiltered water, reverse osmosis water, distilled water or ultrapure water can be used.
The content of the water in the ink is not particularly limited, and can be appropriately selected according to the purpose.

<Pigment>
The pigment is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include black and color inorganic pigments and organic pigments. One of these may be used alone, or two or more may be used in combination.
Examples of the inorganic pigment include, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red and chromium yellow, they are produced by known methods such as contact method, furnace method, thermal method and the like. Carbon black can be used.
Examples of the organic pigment include azo pigments, azomethine pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, aniline black and the like. Among these, azo pigments, polycyclic pigments and the like are more preferable.
Examples of the azo pigment include azo lake, insoluble azo pigment, condensed azo pigment, and chelate azo pigment.
Examples of the polycyclic pigment include phthalocyanine pigment, perylene pigment, perinone pigment, anthraquinone pigment, quinacridone pigment, dioxazine pigment, indigo pigment, thioindigo pigment, isoindolinone pigment, quinofarone pigment, rhodamine B lake pigment, etc. Can be mentioned.
Examples of the dye chelates include basic dye chelates and acid dye chelates.
Examples of black are carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide Etc., organic pigments such as aniline black (C.I. pigment black 1), and the like.
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 It is preferable that it has -150 mL / 100 g, 0.5%-10% of volatile matter, and pH 2-9.
A commercial item can be used as said carbon black, As said commercial item, for example, No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven 700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal 400R, 330R, 660R, Mogul L, Monarch 700, The same 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot); color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S160, S160 S170, Printex 35, U, V, 140 U, 140 V, Special Black 6, 5, 4 A, 4 (all manufactured by Degussa), and the like.
There is no restriction | limiting in particular as a pigment which can be used for yellow ink as a thing for said color, 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.
The pigment that can be used for the magenta ink is not particularly limited and may be appropriately selected according to the purpose. 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 for the cyan ink is not particularly limited and may be appropriately selected according to the 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 one newly produced for the present invention.
The pigment is not particularly limited, and it is possible to use a self-dispersible pigment in which a phosphorus-containing group such as phosphoric acid or phosphonic acid is chemically modified on the pigment surface. In the present invention, even with a pigment having no chemical modification of a phosphorus-containing group on the pigment surface, high image density can be obtained, and an ink jet recording ink excellent in storage stability and ejection recovery can be provided.
As a yellow pigment, C.I. I. Pigment yellow 74, C.I. I. Pigment red 122, C.I. I. Pigment bio red 19, C.I. I. By using pigment blue 15: 3, it is possible to obtain a well-balanced ink with excellent color tone and light resistance.

The volume average particle diameter (D50) of the pigment is not particularly limited and may be appropriately selected depending on the purpose, but 150 nm or less is preferable and 100 nm or less is more preferable. When the volume average particle diameter (D50) is 150 nm or less, the ejection stability may be improved, and the occurrence of nozzle clogging and ink bending may be prevented.
Here, the 50% average particle size of the pigment shows a value of D50% measured by a dynamic light scattering method using Microtrac UPA manufactured by Nikkiso Co., Ltd. under 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.

As the pigment, water, a pigment and, if necessary, a dispersing agent are mixed, and then dispersed by a dispersing machine to adjust the particle size, it is preferable that 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, dispersing the mixture with a dispersing machine, and adjusting the particle size.
The pigment dispersion thus obtained is preferably subjected to degassing 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 subjected to degassing by filtering coarse particles with a filter, a centrifugal separator, etc., as necessary.
The pigment dispersant in the pigment dispersion is preferably a polymer containing the structural unit represented by the general formula (1). Other usable dispersants include, for example, various surfactants such as anionic surfactants, cationic surfactants, amphoteric surfactants and nonionic surfactants, Na formalin naphthalene sulfonate condensates, polymer type Dispersants, 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 taurine salts, polyoxyalkyl ethers Sulfate salt, polyoxyethylene alkyl ether phosphate salt, rosin acid soap, castor oil sulfuric acid ester salt, lauryl alcohol sulfuric acid ester salt, alkylphenol type phosphoric acid ester, naphthalene sulfonate formalin condensation product, alkyl type phosphoric acid ester, alkyl allyl sulfone hydrochloric acid, Diethyl sulfo borate, diethyl hexyl sulfo borate, dioctyl sulfo borate, etc. may be mentioned.
Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.
Examples of the amphoteric surfactant include lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctylpolyaminoethyl glycine, 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, poly Ether surfactants such as oxyallyl alkyl ether; polyoxyethylene oleic acid, polyoxyethylene oleate ester, polyoxyethylene distearate ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquiolate Ester surfactants such as polyoxyethylene monooleate and polyoxyethylene stearate; 2,4,7,9-tetrame Acetylene glycol surfactants such as le-5-decyne-4,7-diol, 3,6-dimethyl-4-octin-3,6-diol, 3,5-dimethyl-1-hexyne-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 may be appropriately selected depending on the purpose, but is 20% by mass It is preferable that it is 80 mass%. When the content is 20% by mass or more, the dispersibility is good, the storage stability of the ink is improved, and as a result, the occurrence of clogging of the nozzle may be prevented. On the other hand, when the content is 80% by mass or less, the viscosity range of the ink may be 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 the ink from drying and an effect as a penetrant.
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, isopropylidene glycerol, 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, petriol; ethylene glycol monoethyl ether Polyhydric alcohol alkyl ethers such as ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl 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 ethers; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolyzinone, ε-caprolactam, γ-butyrolactone, etc. Nitrogen-containing heterocyclic compounds; formamide, N-methylformamide, N, N-dimethylformamide, N, N-dimethyl- -Amides such as methoxypropionamide, N, N-dimethyl-β-butoxypropionamide, etc .; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethanolamine, monoethylamine, diethylamine and triethylamine; dimethylsulfoxide, sulfolane, thiodiethanol etc. And sulfur-containing compounds of the following; 3-ethyl-3-hydroxymethyl oxetane, propylene carbonate, ethylene carbonate, and the like. These may be used alone or in combination of two or more.

Among these, 3-ethyl-3-hydroxymethyl oxetane, isopropylidene glycerol, N, N-dimethyl-β-methoxypropionamide, N, N-dimethyl-β-butoxypropionamide 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 have excellent effects in preventing ejection failure due to water evaporation.
Moreover, as a water-soluble organic solvent having relatively low wettability and permeability, for example, 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, examples of aliphatic diols include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1, 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene 1,2-diol and the like.
The 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, etc. And lower alcohols such as ethanol.

In addition, saccharides can be contained as a wetting agent which is not a water-soluble organic solvent. Examples of the saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like. Specifically, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like can be mentioned. Here, polysaccharides mean sugars in a broad sense, and are used to mean substances including substances widely present in the natural world such as α-cyclodextrin and cellulose. Further, derivatives of these saccharides are represented by reducing saccharides of the above-mentioned saccharides [for example, sugar alcohol [general formula: HOCH ₂ (CHOH) _n CH ₂ OH (wherein n represents an integer of 2 to 5)] Ru. ], Oxidized sugars (eg, aldonic acid, uronic acid and the like), amino acids, thioacids and the like. Among these, sugar alcohols are preferable, and examples of the sugar alcohol include maltitol, sorbite and the like.

The ratio of the pigment to the water-soluble organic solvent greatly affects the ink ejection stability from the head. If the content of the water-soluble organic solvent is low although the pigment solid content is high, the evaporation of water near the ink meniscus of the nozzle may proceed to cause ejection failure.
The content of the water-soluble organic solvent in the ink is not particularly limited and may be appropriately selected according to the purpose, but 10% by mass to 60% by mass is preferable, and 20% by mass to 60% by mass is more preferable. . When the content is 10% by mass or more, the discharge stability of the ink may be improved, and when the content is 60% by mass or less, the drying property may be good. The ink having the content within the more preferable numerical range has an advantage that the drying property and the ejection reliability become 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 mildew agent, rust inhibitor, antioxidant UV absorbers, oxygen absorbers, light stabilizers, and the like.

-Surfactant-
There is no restriction | limiting in particular as said surfactant, According to the objective, it can select suitably, Anionic surfactant, cationic surfactant, nonionic surfactant, amphoteric surfactant, fluorine surfactant Agents, and the like. 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, alkyl benzene 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, 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, and the like. Etc.
Examples of the nonionic surfactant include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl 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 fluorine-based surfactant include materials represented by the following general formulas (I) to (III).

  However, in 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.
The perfluoroalkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 3 carbon atoms, and for example, -C _n F _{2 n-1} (wherein n represents 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 to 4, m is 6 to 25, and p is 1 to 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 F ₉ etc. are mentioned suitably.
R ₂ ⁺ represents a cationic group, and examples thereof include quaternary ammonium groups; alkali metal ions such as sodium and potassium; triethylamine and triethanolamine. Among these, quaternary ammonium groups are particularly preferable. R ₁ ⁻ represents an anionic group, and examples thereof include COO ⁻ , SO ₃ ⁻ , SO ₄ ⁻ , PO ₄ ⁻ , and the like. As for q, 1-6 are preferable.
As said fluorochemical surfactant, what was synthesize | combined suitably may be used, and a commercial item may be used.
Examples of the commercially available product include Surfron S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullard 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, F 1405 , F-474 (all from DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all from DuPont); FT-110 , FT-250, FT-251, FT-400S, FT-150, and FT-400SW (all from Neos, Inc.); PF-151N (Solution ® manufactured lens Inc. Co.); UNIDYNE DSN-403N (manufactured by Daikin Industries) and the like. Among them, 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 improvement in reliability and color development.
The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 0.01% by mass to 5.0% by mass, and more preferably 0.5% by mass to 3%. % By mass is more preferred. When the content is 5.0% by mass or less, the permeability to the recording medium may be improved, and the decrease in the image density and the occurrence of the strike-through may be prevented.

-PH adjuster-
The pH adjuster is not particularly limited as long as the pH can be adjusted to 8.5 to 11 without adversely affecting the prepared ink, and can be appropriately selected according to the purpose.
For example, as the pH adjuster, alcohol amines, hydroxides of alkali metal elements, hydroxides of ammonium, phosphonium hydroxides, carbonates of alkali metals, and the like can be mentioned.
Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like. Examples of the hydroxide of the alkali metal element include lithium hydroxide, sodium hydroxide and potassium hydroxide.
Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, and quaternary phosphonium hydroxide.
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate and potassium carbonate.

-Water dispersible resin-
The water-dispersible resin is excellent in film-forming property (image-forming property), and has high water repellency, high water resistance, high weatherability, and high-water resistance and high image density (high coloring) image recording. It is useful.
Examples of the water-dispersible resin include condensation synthetic resins, addition synthetic resins, and natural polymer compounds.
Examples of the condensation type synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, fluorine resin and the like.
Examples of the addition synthetic resin include polyolefin resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl ester resin, polyacrylic acid resin, unsaturated carboxylic acid resin, and the like.
Examples of the natural polymer compound include celluloses, rosins, natural rubber and the like.
Among these, polyurethane resin particles, acryl-silicone resin particles and fluorine resin particles are preferable.
The average particle size (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and in the case of the same composition, the smaller the particle size, the higher the viscosity at the same solid content.
The average particle size (D50) of the water-dispersible resin is not particularly limited and may be appropriately selected depending on the purpose, for the reason that the ink does not have an excessively high viscosity, and is preferably 50 nm or more.
In addition, when the particle diameter is several tens of μm, the particle diameter is larger than the nozzle opening of the ink jet head, so it can not be used. If particles having a large particle diameter, even if smaller than the nozzle opening, are present in the ink, the ejection stability is degraded. Therefore, the average particle diameter (D50) is more preferably 200 nm or less in order not to inhibit the ink ejection stability.
The water-dispersible resin preferably has the function of fixing the water-dispersible colorant on the surface of the paper, and is preferably coated at normal 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 depending on the purpose, but is preferably 30 ° C. or less.
In addition, when the glass transition temperature of the water dispersible resin is -40 ° C or lower, the viscosity of the resin film becomes strong and tackiness occurs in the printed matter, and therefore the water dispersible resin has a glass transition temperature of -30 ° C or higher. Is preferred.
The content of the water-dispersible resin in the ink is not particularly limited and may be appropriately selected according to the purpose, but it is preferably 1% by mass to 15% by mass, and 2% by mass to 7% by solid content. % Is more preferable.

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

-Rust inhibitor-
Examples of the antirust agent include acid sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropyl ammonium nitrite, pentaerythritol tetranitrate, dicyclohexyl ammonium nitrite, and the like.

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

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

<Use of ink>
The ink of the present invention can be used in inkjet recording applications, spray coating applications, letterpress printing applications, intaglio printing applications, stencil printing applications, writing tools applications, stamp applications, etc., and it is particularly preferable to use in inkjet recording applications .

(Ink jet recording method and ink jet recording apparatus)
The ink jet recording apparatus of the present invention at least includes an ink jetting means for jetting the ink of the present invention to record an image. Specifically, the ink jet recording apparatus of the present invention comprises at least a recording head and a maintenance and recovery apparatus, and further comprises other means such as a stimulation generating means and a control means as required.
The inkjet recording method of the present invention at least includes an ink flying step of flying an ink of the present invention to record an image. Specifically, a stimulus is applied to the ink of the present invention through an ink jetting means, and the ink is ejected from the recording head to at least an ink jetting step of recording an image on a recording medium. That is, the ink jet recording method of the present invention at least includes an ink jetting step, and further includes other steps appropriately selected as necessary, such as a stimulus generation step, a control step and the like.

Hereinafter, the ink jet recording method of the present invention will be described in detail through the description of the ink jet recording apparatus of the present invention.
The inkjet recording apparatus applies a stimulus to each of the inks of the present invention via an ink jetting unit, and ejects the ink from the nozzles of the recording head to record an image. The stimulation can be generated by, for example, the stimulation generation unit, and the stimulation is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Can be mentioned.
These may be used alone or in combination of two or more. Among these, heat and pressure are suitably mentioned.
In addition, as said stimulation generation means, a heating apparatus, a pressurization apparatus, a piezoelectric element, a vibration generator, an ultrasonic oscillator, a light etc. are mentioned, for example. For example, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to film boiling of a liquid using an electrothermal transducer such as a heating resistor, a shape memory alloy actuator using metal phase change due to temperature change, electrostatic force The electrostatic actuator etc. to be used are mentioned.
There is no restriction | limiting in particular as an aspect of flight of the said recording ink, According to the kind etc. of the said stimulation, it can be different. For example, when the stimulus is "heat", heat energy corresponding to a recording signal is applied to the recording ink in the recording head using, for example, a thermal head, and the heat energy causes air bubbles in the recording ink. And the recording ink is ejected as droplets from the nozzle holes of the recording head according to the pressure of the air bubbles. When the stimulus is "pressure", for example, the piezoelectric element is bent by applying a voltage to the piezoelectric element bonded to a position called a pressure chamber in the ink flow path in the recording head, and the volume of the pressure chamber And the recording ink is ejected as droplets from the nozzle holes of the recording head.
The droplets of the recording ink to be ejected preferably have a size of, for example, 3 to 40 pl. Further, the speed of discharge and ejection is preferably 5 to 20 m / s, the driving frequency thereof is preferably 1 kHz or more, and the resolution thereof is preferably 300 dpi or more.

It is preferable that the recording head has a large number of nozzles, and has any of a head unit and a recording unit for forming ink droplets in the ink set by the action of energy and discharging the ink. Further, the recording head includes a liquid chamber, 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 either silicone or 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.
Preferably, the ink jet recording apparatus of the present invention has a sub tank for supplying the ink onto the recording head, and the sub tank is replenished with the ink from the ink cartridge through the supply tube.

  The maintenance and recovery apparatus covers the recording head, at least one suction cover means (suction cap) in communication with the suction force generation means, and at least one which covers the recording head and is not in communication with the suction force generation means. It comprises a non-suction capping means (moisturizing cap), and optionally further means. As described above, by providing the suction cap and the moisturizing cap, the amount of ink consumed in the maintenance operation for ensuring reliability is smaller than in the configuration in which all the caps are suction caps, and the time taken for the maintenance operation Waste of ink can be prevented. There is no restriction | limiting in particular as said maintenance and recovery apparatus, Although it can select suitably according to the objective, For example, what was described in Unexamined-Japanese-Patent No. 2005-170035 etc. can be used.

  The ink jet recording apparatus of the present invention preferably has a reversing means which reverses the recording surface of the recording medium to enable double-sided printing. 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 conveyance belt, and conveyance means for charging the surface of the conveyance belt and conveying it while holding the recording medium. In this case, it is particularly preferable to charge the transport 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 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 consisting of a first head and a second head. FIG. 2 shows a four-head type comprising a first head, a second head, a third head, and a fourth head.
In the two-head type, any one of the first head and the second head is covered with suction cover means (suction cap) in communication with the suction force generation means, and the other is not in communication with the suction force generation means Covered with cover 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 moisturizing cap.
In the four-head type shown in FIG. 2, at least one of the first to fourth heads is covered with suction cover means (suction cap) communicating with the suction force generation means, and the others are in communication with the suction force generation means The cover is covered with a non-suction cover means (moisturizing cap). 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 moisturizing cap.
In the 2-head type of FIG. 1, when performing full-color recording, ink of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is used in 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 a maintenance and recovery device will be described with reference to FIG. FIG. 3 is a perspective view of the ink jet recording apparatus as viewed from the front side.
The inkjet recording apparatus shown in FIG. 3 includes an apparatus main body 1, a paper feed tray 2 for loading a sheet mounted on the apparatus main body 1, and a sheet on which an image is recorded (formed) mounted on the apparatus main body 1 (recording medium And a cartridge loading unit 6 which protrudes forward from the front surface 4 and is lower than the upper surface 5 at one end of the front surface 4 of the apparatus main body 1. An operation unit 7 such as an operation key or a display is disposed on the upper surface of the cartridge loading unit 6. In the cartridge loading unit 6, a main tank (hereinafter referred to as "ink cartridge") 10, which is a liquid storage tank as a liquid replenishment means, is replaceably mounted, and has a front cover 8 which can be opened and closed. .
Here, the ink cartridge contains the ink of the present invention in a container, and may further constitute other members appropriately selected as necessary. The container is not particularly limited in its shape, structure, size, and material, and can be appropriately selected according to the purpose. As an example, one having at least an ink bag formed of an aluminum laminate film, a resin film or the like is preferably mentioned.
For example, the ink cartridge is filled into the ink bag from the ink inlet, and after being evacuated, the ink inlet is closed by fusion. At the time of use, the ink discharge port made of a rubber member is supplied to the apparatus by sticking the needle of the apparatus main body. The ink bag is formed of a packaging member such as an air-impermeable aluminum laminate film. The ink bag is usually housed in a plastic cartridge case, and is detachably mounted to various ink jet recording apparatuses.

Next, the mechanical part of the ink jet recording apparatus of FIG. 3 will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic configuration view for explaining the entire configuration of the mechanism portion, and FIG. 5 is a plan view for explaining the main portion of the mechanism portion.
The carriage 33 is slidably held in the main scanning direction by the guide rods 31 and the stays 32, which are guide members extending laterally over the left and right side plates 21A and 21B constituting the frame 21, and the carriage scanning in FIG. It moves and scans in the direction (main scanning direction).
On the carriage 33, a plurality of recording heads 34 consisting of an inkjet head, which is a droplet discharge head for discharging ink droplets (ink droplets), are arranged in a direction intersecting a main scanning direction with a plurality of nozzles. The ink droplet ejection direction is directed downward.
Here, the recording head 34 is, for example, a recording head 34 y which discharges droplets of yellow (Y), a recording head 34 m which discharges droplets of magenta (M), and a recording head which discharges droplets of cyan (C) The recording head 34k discharges droplets of black (Bk) 34c. When the term "recording head 34" is used, the colors are not distinguished. The head configuration is not limited to these examples, and may be configured using one or more recording heads having one or more nozzle arrays that discharge droplets of one or more colors. .
As a droplet discharge head constituting the recording head 34, a piezoelectric actuator such as a piezoelectric element, a thermal actuator utilizing a phase change due to film boiling of a liquid using an electrothermal conversion element such as a heating resistor, a metal phase due to temperature change It is possible to use a shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like as an energy generating means for discharging a droplet.
In the carriage 33, sub-tanks 35y, 35m, 35c, and 35k (referred to as "sub-tanks 35" when the colors are not distinguished) for mounting the respective colors of ink to the respective recording heads 34 are mounted. The sub-tank 35 is supplied with ink from the ink cartridges 10 of each color (referred to as "ink cartridges 10y, 10m, 10c, 10k" to distinguish each color) via the ink supply tubes 37 of each color. It is like that.

Here, the ink cartridge 10 is stored in the cartridge loading unit 6, as also shown in FIG. The cartridge loading unit 6 is provided with a supply pump unit 23 for feeding the 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 fixedly held by the main body side holder 25 on the rear plate 21C constituting the frame 21 in the middle of the crawling. Furthermore, the carriage 33 is also fixed by the fixing rib 26.
In FIGS. 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 sheet feeding portion for feeding the sheets 42 stacked on the sheet stacking portion (bottom plate) 41 of the sheet feeding tray 2, a half-moon roller (feeding A paper roller 43 and a separation pad 44 facing the paper feed roller 43 and made of a material having a large coefficient of friction are provided, and the separation pad 44 is biased toward the paper supply roller 43 side.
Then, as a conveyance unit for conveying the sheet 42 supplied from the sheet supply unit below the recording head 34, the conveyance belt 51 for electrostatically attracting and conveying the sheet 42, and the sheet supply unit A counter roller 52 for conveying the sheet 42 fed through the guide 45 with the conveying belt 51 and conveying the sheet 42, and the sheet 42 fed almost vertically upward are turned by approximately 90 ° and copied on the conveying belt 51. And a leading end pressure roller 55 biased toward the conveyance belt 51 by the pressing member 54. Further, a charging roller 56 which 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 wound around the conveyance roller 57 and the tension roller 58 so as to rotate in the belt conveyance direction in FIG. 5. The charging roller 56 is in contact with the surface layer of the conveyance belt 51 and is arranged to be rotated following the rotation of the conveyance belt 51, and applies 2.5 N to both ends of the shaft as a pressing force.
Further, on the back side of the conveyance belt 51, a guide member 61 is disposed corresponding to the printing area by the recording head. The guide member 61 protrudes toward the recording head 34 more than the tangent of the two rollers (conveying roller 57 and tension roller 58) whose upper surface supports the conveying belt 51. As a result, the transport belt 51 is pushed up and guided by the upper surface of the guide member 61 in the printing area, so that high-precision planarity is maintained.
Furthermore, 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 conveyance belt 51, a paper discharge roller 72, and a paper discharge roller 73 are provided. The sheet discharge tray 3 is provided below the sheet 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 a certain extent in order to increase the amount of stock on the paper discharge tray 3.
Further, a double-sided sheet feeding unit 81 is detachably mounted on the back of the apparatus body 1. The duplex feeding unit 81 takes in the sheet 42 returned by the reverse rotation of the conveyance belt 51, reverses the sheet 42, and feeds the sheet 42 again between the counter roller 52 and the conveyance belt 51. In addition, a manual sheet feeding unit 82 is provided on the upper surface of the double-sided sheet feeding unit 81.

Further, as shown in FIG. 5, a maintenance recovery device (hereinafter referred to as “sub system”) for maintaining and recovering the state of the nozzles of the recording head 34 in the non-printing area on one side of the carriage 33 in the scanning direction. (Sometimes referred to as 91). In this subsystem 91, cap members 92a to 92d (hereinafter also referred to as "caps") for capping the nozzle surfaces of the recording head 34 (hereinafter referred to as "caps 92") There is also a wiper blade 93, which is a blade member for wiping the nozzle surface, and an empty ink droplet which is used to eject ink droplets that do not contribute to recording in order to eject thickened ink. A wiper cleaner 95 (see FIG. 7), which is a cleaning member formed integrally with the discharge receptacle 94 and the empty discharge receptacle 94 and removing ink adhering to the wiper blade 93, and the wiper blade 93 when cleaning the wiper blade 93. Provided with a cleaner roller 96 or the like that constitutes a cleaner means that presses against the wiper cleaner 95 side That.
In addition, as shown in FIG. 5, in the other non-printing area on the other side in the scanning direction of the carriage 33, in order to discharge thickened ink during recording or the like, idle discharge is performed to discharge droplets not contributing to recording. An empty discharge receptacle 98 for receiving the liquid droplets is disposed, and the empty discharge receptacle 98 is provided with an opening 99 along the nozzle row direction of the recording head 34 and the like.
In the ink jet recording apparatus configured as described above, the sheet 42 is 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 conveying belt 51 and the counter roller The sheet 52 is transported while being sandwiched therebetween. Further, the sheet 42 is guided at its leading end by the conveyance guide 53 and pressed against the conveyance belt 51 by the leading end pressure roller 55, and the conveyance direction of the sheet 42 is changed by about 90 °.
At this time, the control circuit causes the high voltage power supply to alternately repeat positive output and negative output to the charging roller 56, that is, an alternating voltage is applied, and the conveying belt 51 alternates in charging voltage pattern, that is, the winding direction. In the sub-scanning direction, plus and minus are alternately charged in a strip shape with a predetermined width. When the sheet 42 is fed onto the conveyance belt 51 charged alternately in the plus and minus directions, the sheet 42 is electrostatically attracted to the conveyance belt 51, and the sheet 42 is moved in the sub scanning direction by the circumferential movement of the conveyance belt 51. It is transported. Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are discharged onto the stopped sheet 42 to record one line, and after the sheet 42 is conveyed by a predetermined amount, Record the line of The recording operation is ended by receiving the recording end signal or a signal that the rear end of the sheet 42 has reached the recording area, and the sheet 42 is discharged to the sheet discharge tray 3.
In addition, while waiting for printing (recording), the carriage 33 is moved to the subsystem 91 side, the recording head 34 is capped by the cap member 92, and the nozzle is kept wet to prevent discharge failure due to ink drying. . Further, in a state where the recording head 34 is capped by the cap member 92, the ink is suctioned from the nozzles (referred to as "nozzle suction" or "head suction"), and recovery operation is performed to discharge thickened ink or bubbles. In addition, before the start of recording, in the middle of recording, etc., an idle discharge operation is performed to discharge ink not related to the recording. As a result, the stable ejection performance of the recording head 34 is maintained.

Next, the outline of the configuration of the subsystem 91 including the maintenance and recovery device in the ink jet printing apparatus according to the present invention will be described with reference to FIGS. 6 is a plan view of the main part of the system, FIG. 7 is a schematic diagram of the system, and FIG. 8 is a right side view of FIG.
In the frame (maintenance device frame) 111 of the subsystem 91, two cap holders 112A and 112B as cap holding mechanisms, a wiper blade 93 as a wiping member including an elastic body as a cleaning means, and a carriage lock 115 And are each held so as to be vertically movable (vertically movable). An idle discharge receptacle 94 is disposed between the wiper blade 93 and the cap holder 112A, and the wiper blade 93 is a cleaning member for the idle discharge receptacle 94 from the outside of the frame 111 to clean the wiper blade 93. A wiper cleaner 118, which is a cleaner means including a cleaner roller 96 which is a cleaning member for pressing against the wiper cleaner 95, is pivotally held.
The cap holders 112A and 112B (referred to as "cap holder 112" when not distinguished) respectively hold two caps 92a and 92b and caps 92c and 92d which respectively cap the nozzle surfaces of the two recording heads 34. .
Here, a tubing pump (suction pump) 120, which is suction means, is connected to the cap 92a held by the cap holder 112A closest to the printing area via the flexible tube 119, and the other caps 92b, 92c, 92 d does not connect the tubing pump 120. That is, only the cap 92a is used as a suction (recovery) and moisturizing cap (hereinafter, may be referred to as a "suction cap"), and the other caps 92b, 92c, and 92d are all used as simple moisturizing caps. Therefore, when the recovery operation of the recording head 34 is performed, the recording head 34 performing the recovery operation is selectively moved to a position where it can be capped by the suction cap 92 a.
A cam shaft 121 rotatably supported by the frame 111 is disposed below the cap holders 112A and 112B, and cap cams 122A and 122B for raising and lowering the cap holders 112A and 112B are disposed on the cam shaft 121. The wiper cam 124 for moving the wiper blade 93 up and down, the carriage lock cam 125 for moving the carriage lock 115 up and down through the carriage lock arm 117 A roller 126 as a rotating body, which is a discharge impact 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 when lowered, the wiper cleaner 118 advances and is lowered while being held between the cleaner roller 96 of the wiper cleaner 118 and the wiper cleaner 95 of the idle discharge receiver 94. The ink adhering to 93 is scraped off into the empty discharge receptacle 94.
The carriage lock 115 is urged upward (in the locking direction) by a compression spring and raised and lowered via a carriage lock arm 117 driven by the carriage lock cam 125.
Then, in order to rotationally drive the tubing pump 120 and the cam shaft 121, the pump gear 133 provided on the pump shaft 120a of the tubing pump 120 is engaged with the motor gear 132 provided on the motor shaft 131a for rotation of the motor 131 An intermediate gear 136 having a one-way clutch 137 is engaged with an intermediate gear 134 integral with 133 via an intermediate gear 135, and is fixed to a camshaft 121 via an intermediate gear 139 coaxial with the intermediate gear 136. The cam gear 140 is engaged. The intermediate shaft 141, which is the rotational shaft of the intermediate gears 136 and 138 with the clutch 137, is rotatably held by the frame 111.
In addition, the cam shaft 121 is provided with a home position sensor cam 142 for detecting a home position, and the home position sensor provided in this subsystem 91 operates the home position lever when the cap 92 comes to the lowermost end. The sensor is opened to detect the home position of the motor 131 (other than the pump 120). When the power is on, it moves up and down (raising and lowering) regardless of the position of the cap 92 (cap holder 112), does not detect the position until the movement starts, and is determined after detecting the home position (during the ascent) of the cap 92. Move to the lower end. Thereafter, the carriage moves laterally to return to the cap position after position detection, and the recording head 34 is capped.
Reference numeral 142 indicates a home position sensor cam.

Next, the holding mechanism of the cap 92 and the elevating mechanism (vertical movement mechanism) will be described in detail with reference to FIG. FIG. 9 is an explanatory side view of the cap holding elevating mechanism.
The cap holder 112A, which is a cap holding mechanism, holds the cap 92a and the cap 92b (some of which may be collectively referred to as "cap 92A") in an elevating manner, and the bottom surface of the holder 151 and the bottom portion of the cap 92A. A spring 152 for urging the cap 92A upward, and a slider 153 for holding the holder 151 movably in the front-rear direction (the direction in which the nozzles of the recording head 34 are aligned).
In the cap 92A, the guide pins 150a provided at both ends are vertically inserted into the guide grooves of the holder 151 so as to move up and down, and the guide shafts 150b provided on the bottom are inserted into the holder 151 so as to move vertically. Can be vertically moved. Springs 152, 152 interposed between the cap 92A and the cap holder 151 bias the caps 92a, 92b upward (in the direction of pressing on the nozzle surface side at the time of capping).
The slider 153 is structured such that the whole of the slider 153, the holder 151 and the cap 92A can move up and down by slidably fitting guide pins 154 and 155 provided on the front and rear ends into guide grooves 156 formed in the frame 111.
Then, the cam pin 157 provided on the lower surface of the slider 153 is fitted to the cam groove (not shown) of the cap cam 122A, and the slider 153 is rotated by the rotation of the cap cam 122A which moves in unison 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 are moved up and down.
Furthermore, 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 for holding the caps 92c and 92d (these may be collectively referred to as "cap 92B") and the configuration for moving the cap up and down are similar to the above, and thus the 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 is rotated, and by rotation of the cam shaft 121, the cams 122A and 122B fixed to the cam shaft 121 are rotated. , Cap 92A and 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 recordings by an ink jet recording method, and particularly suitable for, for example, an ink jet recording printer, a facsimile machine, a copying machine, a printer / fax / copier complex machine, etc. It can be applied to

-Ink recording material-
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 comprises an image recorded by 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 can land 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 or aluminum sulfate (sulfuric acid band) and the like, and when the ink jet recording ink of the present invention lands on the same paper, polyvalent metal ions, specifically In these, divalent or trivalent metal ions such as calcium, magnesium and aluminum are eluted.
As mentioned above, although any paper can be used in the present invention, plain paper is particularly preferred. Here, “plain paper” refers to 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. This refers to paper media in general for image-passing and transportable image support. Plain paper seems to be a translation of Plain Paper, but the mainstream of Plain Paper is fine paper today. Therefore, high-quality paper is often referred to as plain paper, and an electrophotographic image medium as a typical image forming technology using this is commonly known as PPC (Plain Paper Copy).
The ink according to the present invention reacts with the above-described polyvalent metal ion to coagulate the pigment and obtain a high image density. However, among the sheets exemplified above, for example, plain paper, it has been difficult to realize high image density.
Most of fillers, sizing agents, fixing agents, and the like contained in plain paper are metal salts having poor water solubility. Moreover, even if it contains a water-soluble metal salt, its content is small. Therefore, compared with the paper which processed water-soluble polyvalent metal salt etc. on the paper surface, plain paper has little elution of polyvalent metal ion, and the image density improvement effect was not acquired in the prior art.
In the present invention, high image density can be realized with paper having little elution of polyvalent metal ions as well as the above-mentioned processed paper as well as plain paper. Examples of commercial products of 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 paper of 1.0 × 10 ^{−4 to} 5.0 × 10 ⁻⁴ [g / g]. When the amount of Ca ions is 1.0 × 10 ⁻⁴ [g / g] or more, the effect of improving the image density by the reaction aggregation with the pigment dispersant is improved. Further, when the Ca ion content is 5.0 × 10 ⁻⁴ [g / g] or less, since the penetration of the ink into the paper is not inhibited, 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 cut into 2.5 cm (. +-. 0.5 cm) .times.3.5 cm (. +-. 0.5 cm) square pieces of paper, pure water is filtered with a 0.8 .mu.m cellulose acetate filter (manufactured by Advantec Co., Ltd.) After removing the foreign matter, the Ca ion contained in the immersion liquid is quantified by an ICP emission spectrophotometer. The Ca ion concentration [ppm] obtained here is multiplied by 200 g which is the weight of high pure water, and it is further divided by 16 g which is the weight of the soaked paper, and the amount of Ca ion eluted from the paper [g / g Calculate].
For example, the amount of Ca ions in MyPaper (manufactured by Ricoh Co., Ltd.) is 4.3 × 10 ⁻⁴ [g / g], and the amount of Ca ions in Xerox 4024 (manufactured by Fuji Xerox Co., Ltd.) is 1.7 × 10 ⁻⁴ [g / g]. g / g].

  EXAMPLES Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples. The term "parts" refers to "parts by mass" unless otherwise specified. "%" Represents "% by mass" unless otherwise specified.

<Synthesis of Monomer>
Raw material synthesis
Synthesis of aminomethylenediphosphonic 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 replacing with nitrogen. Thereafter, it 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 the remaining highly viscous residue was dissolved by adding 200 parts of water while cooling with water, and the mixture was heated to reflux for 4 hours. After that, when it was cooled, crystals of the desired product were precipitated. The resultant was collected by filtration and dried to obtain 50.3 parts of a desired product. Mass spectrometry by ESI showed m / z (+) 191.75, which was in agreement with the calculated molecular weight of 191.02 + 1 with an error range.

[Monomer 1-1: Methacrylamide methylene diphosphonic acid ditetraethyl ammonium salt]
Into a reaction vessel, 19.2 parts of aminomethylenediphosphonic acid is added, and then an aqueous solution in which 179.8 parts of tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd., 35% aqueous solution) is dissolved with 83.1 parts of ion exchanged water Completely dissolved with stirring. Next, 13.5 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly dropped while the flask was cooled 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 desired product.
An acid value was determined by dissolving 1.1 parts of this substance in 110 parts of ion-exchanged water and performing neutralization titration with 0.1 N KOH methanol solution using thymolphthalein (manufactured by Kanto Chemical Co., Ltd.) as an indicator. . This result was equivalent to 108 mg KOH / g, which was calculated as four acid groups becoming two tetraethyl ammonium salts.

[Monomer 1-2: Acrylamido methylene diphosphonic acid ditetra-n-butyl ammonium salt]
In the synthesis of monomer 1-1, 11.6 parts of acrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) is used instead of 13.5 parts of methacrylic acid chloride, and 35% of tetraethyl ammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) 27.27 parts of tetrabutylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd., 40% aqueous solution) and 33.7 parts of ion exchange water are used instead of 179.8 parts of an aqueous solution and 83.1 parts of ion exchange water. Similarly, 65 parts of the desired product were obtained.

[Precursor 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.
A solution of 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of methylene chloride was added dropwise to this solution with stirring over 2 hours, and then stirred at room temperature for 6 hours . The resulting reaction solution is washed with water, and the organic phase is isolated, dried over magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography using methylene chloride / methanol (volume ratio 98/2) mixed solvent 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.degree. A solution of 24.0 g (155 mmol) of 2-methacryloyloxyethyl isocyanate (Karen MOI, manufactured by Showa Denko KK) dissolved in 20 mL of dry methyl ethyl ketone is added dropwise to this solution while stirring over 1 hour, and then the solution is heated to 70 ° C. The mixture was stirred for 12 hours. After cooling to room temperature, the solvent was distilled off. The residue is purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (99/1 by volume) as an eluent to obtain 57.0 g of a monomer having a structure represented by the following structural formula 1 I got one.

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

[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 1 Having Diphosphonic Acid Groups
A reaction vessel equipped with a gas inlet tube, a thermometer and a reflux condenser was charged with 36 parts of monomer 2-1 and dissolved in 370 parts of N, N-dimethylformamide (DMF). The aqueous solution which melt | dissolved 24 parts of monomers 1-1 in 75 parts of ion-exchange water was added there, and it heated at 75 degreeC under argon atmosphere. Thereto, a DMF solution prepared by dissolving 1.3 parts of 2,2′-azobisisobutyronitrile (AIBN) (manufactured by Tokyo Kasei Kogyo Co., Ltd.) in 30 parts of DMF was added dropwise with a dropping wax. Stirring was continued at 75 ° C. for 6 hours and then cooled to terminate polymerization.
The insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixture of tetrahydrofuran and hexane (volume ratio 40: 100). Then, the solvent was removed by an evaporator, and the residue was vacuum dried at 60 ° C. to obtain 56 parts of a resin.
One part of this resin was dissolved in 100 parts of deionized water, and thymolphthalein as an indicator was titrated with a 0.1 N KOH methanol solution to obtain an acid value, which was 43 mg KOH. The value was in good agreement with the value 43 mg KOH calculated as copolymerized according to the charge ratio from the acid value of monomer 1-1.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while being neutralized with a tetraethylammonium hydroxide aqueous solution. It was 2.3 mPa * s when the viscosity of this solution was measured at 25 degreeC. The 10% by weight aqueous resin solution thus obtained was used for pigment dispersion preparation.
It is found from the titration results of the monomer raw material alendroonic acid that three out of four OH groups of phosphonic acid are neutralized at the time of discoloration of thymolphthalein, so the resin obtained by neutralization is Of the four OH groups, three were neutralized with tetraethylammonium ion.

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 synthesis was performed under the reaction conditions shown in Table 2. Polymers 2 to 16 were synthesized in the same manner as in Synthesis Example 1 except for the above.
As α-thioglycerol as a chain transfer agent, one manufactured by Tokyo Chemical Industry Co., Ltd. was used.
The obtained polymers 2 to 16 were each neutralized or not neutralized to a salt composition as shown in Table 1 (M of the general formula (1)), and were used as they were for the preparation of a pigment dispersion. The viscosities at 25 ° C. of a 10% by weight aqueous solution of each of the polymers 2 to 16 are shown in Table 1.

  In Table 1, TetraEtA represents tetraethylammonium ion, and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H and the like, 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-A-2009-513802, which is publicly known.

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

[Synthesis of Monomer 5 for Comparative Synthesis Example]
25 parts of alendronate (manufactured by Tokyo Chemical Industry Co., Ltd.) is placed in a flask, and then an aqueous solution consisting of 179.8 parts of tetraethylammonium hydroxide (manufactured by Tokyo Chemical Industry, 35% aqueous solution) and 83.1 parts of ion exchanged water is charged. And completely dissolved with stirring. Next, while the flask was cooled to 5 ° C., 13.32 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly dropped. 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 three times with methylene chloride, and the remaining aqueous solution was dropped into 800 parts of methanol to precipitate the desired product. Filtration gave 55 parts of the desired product monomer 5, tetraethylammonium 1-hydroxy-4-methacrylamidobutane-1,1-diylbis (hydrogen phosphonate).

Comparative Synthesis Example 3 Synthesis of Polymer 19
In an argon atmosphere, 450 parts of N, N-dimethylformamide (DMF) was placed in a reaction vessel equipped with a gas inlet tube, a thermometer and a reflux condenser, and heated to 75 ° C. Thereto, each of 558 parts of an aqueous solution of 75 parts of a monomer for comparison synthesis 5 and 525 parts of a DMF solution of 75 parts of benzyl acrylate and 14 parts of a DMF solution in which 14 parts of 2,2'-azobisisobutyronitrile have been dissolved 12 Divided into 30 minutes each. Stirring was continued for a further 4 hours after everything had been added and then cooled to stop the polymerization.
The precipitate was separated by filtration, washed with hexane and dried to obtain 140 parts of a copolymer (polymer 19). The acid value of the obtained resin was measured in the same manner as in the synthesis example, and the resin was neutralized using a tetraethylammonium hydroxide aqueous solution and used as a resin solution.

Comparative Synthesis Example 4 Synthesis of Polymer 20
In an argon atmosphere, 182 parts of N, N-dimethylformamide (DMF, manufactured by Kanto Chemical Co., Inc.) was placed in a reaction vessel equipped with a gas inlet tube, a thermometer, and a reflux condenser, 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) 212 parts of a DMF solution prepared by dissolving 6 parts of Chemical Industries, Ltd./abbreviated as DMAPAA hereinafter in DMF, and 2,2′-azobisisobutyro nitrile (abbreviated as Tokyo Chemical Industry Co., Ltd./abbreviated as AIBN) 5 187.4 parts of a DMF solution in which 4 parts were dissolved in 182 parts of DMF was added in 12 portions each and every 30 minutes. Stirring was further continued at 75 ° C. for 4 hours after all the addition, and then the polymerization was stopped by cooling.
Then, it processed similarly to the comparative synthesis example 3, and used as a resin solution.

[Synthesis of Monomer 6 for Comparative Synthesis Example]
Twenty-five parts of alendronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a flask, and then an aqueous solution prepared by dissolving 17.1 parts of sodium hydroxide in 200 parts of ion-exchanged water was charged and completely dissolved with stirring. Next, while the flask was cooled to 5 ° C., 13.32 parts of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was slowly dropped. 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 three times with methylene chloride, and the remaining aqueous solution was dropped into 800 parts of methanol to precipitate the desired product. Filtration gave 35 parts of the desired product monomer 6, sodium 1-hydroxy-4-methacrylamide butane-1,1-diyl bis (hydrogen phosphonate).

Comparative Synthesis Example 5 Synthesis of Polymer 21
Under an argon atmosphere, 193 parts of N, N-dimethylformamide (DMF) was charged into a reaction vessel equipped with a gas inlet tube, a thermometer and a reflux condenser, and heated to 75 ° C. Thereto, 223 parts of an aqueous solution prepared by dissolving 30 parts of a 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-methacryloyloxyethyl ammonium chloride (Tokyo Chemical Industry) Co., Ltd., 6 parts of TMMEAC dissolved in 182 parts of DMF and 212 parts of DMF solution and 5.4 parts of 2,2'-azobisisobutyro nitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 182 parts of DMF 187.4 parts of the DMF solution was added in 12 portions each and added every 30 minutes. Stirring was further continued at 75 ° C. for 4 hours after all the addition, and then the polymerization was stopped by cooling.
Then, it processed similarly to the comparative synthesis example 3 except having neutralized using sodium hydroxide, and it used as a resin solution.

Comparative Synthesis Example 6 Synthesis of Polymer 22
A stearyl acrylate in place of benzyl acrylate in Comparative Synthesis Example 5 was polymerized and treated in the same manner except that DMAPAA was used in place 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]
The following mixture is premixed, and after circulating and dispersing for 10 minutes at a peripheral speed of 10 m / s with a disk type bead mill (manufactured by Shinmaru Enterprises, KDL type, medium: zirconia balls with a diameter of 0.1 mm) The pigment dispersion 1 was obtained by filtration through a membrane filter of 2 μm.
-Carbon black (NIPEX 160, manufactured by Degussa)-16.0 parts by mass-10% by mass aqueous solution of polymer 1-40.0 parts by mass-pure water-44.0 parts by mass

[Pigment Dispersion 2 to Pigment Dispersion 18 Preparation]
Pigment dispersion 2 to pigment dispersion 18 were prepared according to the formulation shown in Table 3 in the same manner as in the preparation of pigment dispersion 1.
In Table 3, the following products were used as pigments other than carbon black.
Pigment Blue 15: 3 Chromo Fine Blue A-220 JC, manufactured by Dainichi Seisei Co., Ltd. Pigment Red 122 Toner Magenta EO 02, Clariant Co., Ltd.

<Production of Ink for Ink Jet Recording>
Example 1
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter with 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 part by mass · 2,2,4-trimethyl-1,3-pentanediol ... ... 1.0 part by mass (water-soluble organic solvent)
Fluorine surfactant ····················· 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
Distilled water: 27.0 parts by mass

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

Example 22
Using the same preparation method as 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)
Fluorine surfactant ····················· 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
·································································· ........ 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, a pigment dispersion 23 using a polymer 17 according to Comparative Synthesis Example 1 was used instead of the polymer 1 in the formulation of the pigment dispersion 1.

Comparative Example 2-7
Using the same preparation method as Comparative Example 1, the 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 according to comparative synthesis example 2-7 was used.

[Evaluation results]
Next, each inkjet ink of Examples 1-22 and Comparative Examples 1-7 was evaluated by the evaluation method shown below. The results are shown in Table 5 below.

<Image density>
64 point characters JIS X 0208 (1997), 2223 prepared by filling the ink prepared in an ink jet printer (IPCO GX 5000 manufactured by Ricoh Co., Ltd.) under an environment of 23 ° C. and 50% RH and manufactured by Microsoft Word 2000 (manufactured by Microsoft Corp.) The chart with the general symbol is printed on plain paper 1 (XEROX 4200, manufactured by XEROX) and plain paper 2 (MyPaper, manufactured by Ricoh Co., Ltd.), and the general symbol of JIS X 0208 (1997), 2223 of the printed surface The color of each part was measured with X-Rite 938 (manufactured by X-Rite Co., Ltd.), and the color was determined according to the following evaluation criteria.
In addition, the printing mode used the mode which changed the "plain paper-standard is quick" mode to "no color correction" from the user setting of the plain paper with the driver attached to the printer.
〔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 gels and can not be dispersed in the ink, and printing can not be performed.
(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 gels and can not be dispersed in the ink, and printing can not be performed.
(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 gels and can not be dispersed in the ink, and printing can not be performed.
(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 gels and can not be dispersed in the ink, and printing can not be performed.

  More than C is practical.

<Preservation of pigment dispersion>
Each pigment dispersion was placed in a polyethylene container, sealed, stored at 70 ° C. for 2 weeks, and the rate of change in viscosity after storage relative to the viscosity before storage was determined from the following equation 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 (RE 500L, manufactured by Toki Sangyo Co., Ltd.), adjusted to 50 revolutions or 100 revolutions according to the viscosity of the sample, and evaluated based on the following criteria. .
[Evaluation criteria]
A: The change rate of viscosity is within ± 5%.
B: The rate of change of viscosity exceeds ± 5% and within ± 8%.
C: The rate of change of viscosity exceeds ± 8% and within ± 10%.
D: The rate of change of viscosity exceeds ± 10% and within ± 30%.
E: The rate of change in viscosity exceeds ± 30% (gelling can not be evaluated).

  More than C is practical.

<Storage stability of ink>
Each ink was filled in an ink cartridge, stored at 60 ° C. for 1 week, and stored at 70 ° C. for 2 weeks, and the change rate of viscosity after storage with respect to the viscosity before storage was determined from the following equation and evaluated according to the following criteria.
Viscosity change rate (%) = (viscosity of ink after storage / viscosity of ink before storage) × 100
The viscosity was measured using a viscometer (RE 500L, manufactured by Toki Sangyo Co., Ltd.), adjusted to 50 revolutions or 100 revolutions according to the viscosity of the sample, and evaluated based on the following criteria. .
[Evaluation criteria]
A: The change rate of viscosity is within ± 5%.
B: The rate of change of viscosity exceeds ± 5% and within ± 8%.
C: The rate of change of viscosity exceeds ± 8% and within ± 10%.
D: The rate of change of viscosity exceeds ± 10% and within ± 30%.
E: The rate of change in viscosity exceeds ± 30% (gelling can not be evaluated).

Table 5 describes the result of storage evaluation at 60 ° C. for one week as “ink storability 1” and the result of storage evaluation at 70 ° C. for two weeks as “ink storability 2”.
More than C is practical.

<Discharge recoverability>
An ink jet printer is filled with the inks of Examples 1 to 2 and Comparative Examples 1 to 7 and left for 3 hours in an HL environment (32 ± 0.5 ° C., 15 ± 5% RH), and then the nozzle check pattern is printed. It was confirmed that there were no discharge defects such as missing dots and flying curves. Then, it was left as it is for another 6 days. After leaving, the quality check paper My Paper (manufactured by Ricoh Co., Ltd.) having a basis weight of 69.6 g / m ² , a size degree of 23.2 seconds, and an air permeability of 21.0 seconds is used. The sheet was printed, and the presence or absence of dot missing or flying deflection was confirmed. When ink dot missing or flying deflection was observed in the nozzle check pattern, the printer nozzle was cleaned as a return operation to normal printing, and the total number of times was evaluated. From the total number of times obtained, the ejection recoverability of each ink was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: Cleaning 0 times.
B: One cleaning.
C: Cleaning twice.
D: Cleaning 3 or more and less than 5 times.
E: Cleaning 5 times or more.

  More than C is practical.

From the results in Table 5, it is found that the ink of the example having the configuration of the present invention is in a practical region in which all of the image density, the stability of the dispersion, the storage stability of the ink, and the ejection recovery property It can be seen that In particular, it is understood that the storage stability and the ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those having the monomer content shown by the general formula (1) and those whose viscosity is controlled in a suitable range have particularly high evaluation results (Examples 1 to 8, 10, 13, 14, 21) ), Improve the overall quality. If the content and the viscosity are out of the preferable ranges, the image density, the storability and the ejection recovery property show a slight deterioration in quality, but they are practicable levels.
The ink of Example 22 in which the polymer having a diphosphonic acid group of the present invention is used as an additive has a somewhat lower overall quality than the other examples in which it is used as a pigment dispersant, but it is feasible It is a level.
On the other hand, those which do not take the constitution of the present invention are inferior in the ink storability and ejection recovery property (Comparative Examples 1 to 7). Even if the image density does not show significant deterioration, the long-term storage and ejection recovery of the ink are not at a practicable level.

Synthesis Example 17 Synthesis of Copolymer 24 Containing Phosphonic Acid Group
In a reaction vessel equipped with a gas inlet tube, a thermometer, and a reflux condenser, 30 parts of monomer 2-1, 6 parts of dimethyl acrylamide (DMAM manufactured by Tokyo Chemical Industry Co., Ltd.), and 500 parts of N, N-dimethylformamide It was dissolved in (DMF). The aqueous solution which melt | dissolved 24 parts of monomers 1-1 in 100 parts of ion-exchange water was added there, and it heated at 75 degreeC under argon atmosphere. Thereto, a DMF solution prepared by dissolving 1.8 parts of 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) in 30 parts of DMF was dropped using a dropping wax. Stirring was continued at 75 ° C. for 6 hours and then cooled to terminate polymerization.
The insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixture of tetrahydrofuran and hexane (volume ratio 40: 100). Subsequently, the solvent was removed by an evaporator, and the residue was vacuum dried at 60 ° C. to obtain 54 parts of a resin.
One part of this resin was dissolved in 100 parts of deionized water, and thymolphthalein as an indicator was titrated with a 0.1 N KOH methanol solution to obtain an acid value, which was 43 mg KOH. The value was in good agreement with the value 43 mg KOH calculated as copolymerized according to the charge ratio from the acid value of monomer 1-1.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while being neutralized with a tetraethylammonium hydroxide aqueous solution. It was 2.5 mPa * s when the viscosity of this solution was measured at 25 degreeC. The 10% by weight aqueous resin solution thus obtained was used for pigment dispersion preparation.
It is found from the titration results of the monomer raw material alendroonic acid that three out of four OH groups of phosphonic acid are neutralized at the time of discoloration of thymolphthalein, so the resin obtained by neutralization is Of the four OH groups, three were neutralized with tetraethylammonium ion.

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), and the general formulas (7a), (7b), (7c) Polymers 25 to 43 were synthesized in the same manner as in Synthesis Example 17 except that mass% of the monomer (3) to be represented was changed, and synthesis was performed under the reaction conditions shown in Table 7.
As α-thioglycerol as a chain transfer agent, one manufactured by Tokyo Chemical Industry Co., Ltd. was used.
The obtained polymers 25 to 43 were each neutralized or not neutralized to a salt composition as shown in Table 6 (M of the general formula (1)), and were used as they were for the preparation of a pigment dispersion. The viscosity at 25 ° C. of a 10% by mass aqueous solution of each of the polymers 25 to 43 is shown in Table 6.

In Table 6, TetraEtA represents tetraethylammonium ion, and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H and the like, M + represents 3 TetraEtA ions and 1 proton.
In Table 6, abbreviations for monomer (3) are shown below.
DMAM: N, N-dimethyl acrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
DMMAM: N, N-dimethyl methacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)
HEAM: 2-hydroxyethyl acrylamide (made 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 is circulated and dispersed for 10 minutes at a peripheral speed of 10 m / s with a disk type bead mill (manufactured by Shinmaru Enterprises Co., Ltd., model KDL, media: zirconia balls with a diameter of 0.1 mm), The 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-10% by mass aqueous solution of polymer 17-40.0 parts by mass-pure water-44.0 parts by mass

[Preparation of pigment dispersion 31 to pigment dispersion 54]
Pigment dispersion 31 to pigment dispersion 54 were prepared according to the formulation (parts by mass) shown in Table 8 in the same manner as in the preparation of pigment dispersion 30.
In Table 8, the following products were used as pigments other than carbon black.
Pigment Blue 15: 3 Chromo Fine Blue A-220 JC, manufactured by Dainichi Seisei Co., Ltd. Pigment Red 122 Toner Magenta EO 02, Clariant Co., Ltd.

<Production of Ink for Ink Jet Recording>
[Example 23]
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter with 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)
Fluorine surfactant ····················· 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
Distilled water: 27.0 parts by mass

[Examples 24 to 47]
Using the same preparation method as in Example 1, the inks of Examples 24-47 were prepared according to the formulation 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)
Fluorine surfactant ····················· 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
·································································· ........ 11.0 parts by mass

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

From the results in Table 10, it is found that the ink of the example having the configuration of the present invention is in a practical range in which all of the image density, the stability of the dispersion, the storage stability of the ink, and the ejection recovery property are practicable. It can be seen that In particular, it is understood that the storage stability and the ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those having the monomer content represented by the general formula (1) and those whose viscosity is controlled in a suitable range have particularly high evaluation results (Examples 23 to 30, 32 to 36, 39, 40) , 47), improve the overall quality. If the content and the viscosity are out of the preferable ranges, the image density, the storability and the ejection recovery property show a slight deterioration in quality, but they are practicable levels.
Although the ink of Example 48 using the polymer having a diphosphonic acid group of the present invention as an additive has a somewhat lower overall quality as compared to the other examples using a pigment dispersant, it is feasible. It is a level.

[Synthesis example 37; Synthesis of copolymer 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, 6 parts of N- [3- (dimethylamino) propyl] acrylamide (DMAPAA, manufactured by Tokyo Chemical Industry Co., Ltd.) Then, it was dissolved in 500 parts of N, N-dimethylformamide (DMF). The aqueous solution which melt | dissolved 24 parts of monomers 1-1 in 100 parts of ion-exchange water was added there, and it heated at 75 degreeC under argon atmosphere. Thereto, a DMF solution prepared by dissolving 1.7 parts of 2,2′-azobisisobutyronitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) in 30 parts of DMF was dropped using a dropping wax. Stirring was continued at 75 ° C. for 6 hours and then cooled to terminate polymerization.
The insoluble matter in the reaction solution was removed, and the reaction solution was washed three times with a mixture of tetrahydrofuran and hexane (volume ratio 40: 100). Subsequently, the solvent was removed by an evaporator, and the residue was vacuum dried at 60 ° C. to obtain 53 parts of a resin.
One part of this resin was dissolved in 100 parts of deionized water, and thymolphthalein as an indicator was titrated with a 0.1 N KOH methanol solution to obtain an acid value, which was 43 mg KOH. The value was in good agreement with the value 43 mg KOH calculated as copolymerized according to the charge ratio from the acid value of monomer 1-1.
Based on this acid value, a 10% by mass resin aqueous solution was prepared while being neutralized with a tetraethylammonium hydroxide aqueous solution. It was 2.4 mPa * s when the viscosity of this solution was measured at 25 degreeC. The 10% by weight aqueous resin solution thus obtained was used for pigment dispersion preparation.
It is found from the titration results of the monomer raw material alendroonic acid that three out of four OH groups of phosphonic acid are neutralized at the time of discoloration of thymolphthalein, so the resin obtained by neutralization is Of the four OH groups, three were neutralized with tetraethylammonium ion.

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), and 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 α-thioglycerol as a chain transfer agent, one manufactured by Tokyo Chemical Industry Co., Ltd. was used.
The obtained polymers 45 to 63 were each neutralized or not neutralized to a salt composition as shown in Table 11 (M of the general formula (1)), and were used as they were for the preparation of a pigment dispersion. The 10 mass% aqueous solution viscosity of each of the polymers 44 to 63 is shown in Table 11.

In Table 11, TetraEtA represents tetraethylammonium ion, and TetraBuA represents tetrabutylammonium ion. In 3TetraEtA, 1H and the like, M + represents 3 TetraEtA ions and 1 proton.
In Table 11, abbreviations of monomers (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-methacryloyloxyethyl ammonium 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 is circulated and dispersed for 10 minutes at a peripheral speed of 10 m / s with a disk type bead mill (manufactured by Shinmaru Enterprises Co., Ltd., model KDL, media: zirconia balls with a diameter of 0.1 mm), 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 mass 10% aqueous solution of polymer 1 40.0 parts by mass Pure water 44.0 parts by mass

[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-220 JC, manufactured by Dainichi Seisei Co., Ltd. Pigment Red 122 Toner Magenta EO 02, Clariant Co., Ltd.

<Production of Ink for Ink Jet Recording>
[Example 49]
The following materials were mixed, stirred for 1.5 hours, and filtered through a membrane filter with 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)
Fluorine surfactant ····················· 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
Distilled water: 27.0 parts by mass [Examples 50 to 73]
Using the same preparation method as Example 49, the inks of Examples 50 to 73 were prepared according to the formulation shown in Table 14.

[Example 74]
Using the same preparation method as 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 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)
Fluorine surfactant ······················ 1.0 part by mass (solid content 100%, manufactured by DAIKIN INDUSTRIES, Unidyne DSN-403N)
································································ ..... 11.0 parts by mass

[Evaluation results]
Next, the tests of <image density>, <preservability of pigment dispersion>, <storage stability of ink>, and <discharge recovery property> shown above are performed to evaluate each ink jet ink of Examples 49 to 74. did. Evaluation criteria for each test are also the same as above. The results are shown in Table 15 below.
In the test of <storage stability of ink>, in Table 15, the evaluation result of storage at 60 ° C. for one week is described as “ink storage stability 1”, and the result of storage evaluation at 70 ° C. for two weeks is described as “ink storage performance 2”. .

From the results in Table 15, it is found that the ink of the example having the configuration of the present invention is in a practical region in which all of the image density, the stability of the dispersion, the storage stability of the ink, and the ejection recovery property are practicable. It can be seen that In particular, it is understood that the storage stability and the ejection recovery property of the ink are greatly improved as compared with the ink of the comparative example.
Among the examples, those having a monomer content indicated by the general formula (1) and those whose viscosity is controlled in a suitable range have particularly high evaluation results (Examples 49 to 56, 58 to 62, 65, 66 , 73), improve the overall quality. If the content and the viscosity are out of the preferable ranges, the image density, the storability and the ejection recovery property show a slight deterioration in quality, but they are practicable levels.
The ink of Example 74 in which the polymer having a diphosphonic acid group of the present invention is used as an additive has a somewhat lower overall quality than the other examples in which it is used as a pigment dispersant, but it is feasible It is a level.

Reference Signs List 1 apparatus body 2 paper feed tray 3 paper discharge tray 4 front surface 5 upper surface 6 cartridge loading unit 7 operation unit 8 front cover 10 ink cartridge 21 frame 21A side plate 21B side plate 21B side plate 21C rear plate 22 flexible cable 23 supply pump unit 25 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 loading section (bottom plate)
42 Paper 43 Half Moon Roller (Feed Roller)
Reference Signs List 44 separation pad 45 guide 51 conveyance belt 52 counter roller 53 conveyance guide 54 holding member 55 leading end pressure roller 56 charge roller 57 conveyance roller 58 tension roller 61 guide member 71 separation claw 72 sheet discharge roller 73 sheet discharge roller 81 double-sided sheet feeding unit 82 manual feed portion 91 subsystem 92 cap 92a cap 92b cap 92c cap 92 d cap 93 wiper blade 94 idle discharge receiver 95 wiper cleaner 96 cleaner roller 98 idle discharge receiver 99 opening 111 maintenance device frame 112A cap holder 112B cap holder 115 carriage lock 117 Carriage lock arm 118 Wiper cleaner 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 138 intermediate gear 139 intermediate gear 140 Cam gear 141 Intermediate shaft 142 Cam for home position sensor 150a Guide pin 150b Guide shaft 151 Holder 152 Spring 153 Slider 154 Guide pin 155 Guide pin 156 Guide groove 157 Cam pin

Japanese Patent Application Publication No. 2009-513802 JP, 2014-114409, A EP 2843013 A1 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 portion of the diphosphonic acid group is tetra 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 general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in 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 portion of the diphosphonic acid group is tetra And an alkyl ammonium salt, and the polymer is a structural unit (1) represented by the general formula (1), a structural unit (2) represented by the general formula (2), and 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 general formula (1) represents a hydrogen atom or a methyl group, and M ⁺ represents a tetraalkylammonium ion or a proton.)

(R ₂ in 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 General Formula (3a) represents a hydrogen atom or a methyl group.)

(R ₄ in General Formula (3b) represents a hydrogen atom or a methyl group, and R ₅ and R ₆ each independently represent 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 portion of the diphosphonic acid group is tetra And the polymer is a structural unit (1) represented by the general formula (1), a structural unit (2) represented by the general formula (2), and the general formula (4a) or An ink comprising at least the structural unit (4) represented by the general formula (4b).

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

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

(R ₁₁ in 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 of 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 an aqueous solution viscosity (concentration 10% by mass, 25 ° C) of the polymer is 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 portion of the diphosphonic acid group It is a tetraalkyl ammonium 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 in that it is a composite.

(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 the 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 portion of the diphosphonic acid group A tetraalkyl ammonium 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 which is 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 the 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 the 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 portion of the diphosphonic acid group 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 formula (8a) or (8b) An ink characterized by being 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 the 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 General Formula (8a) represents a hydrogen atom or a methyl group, R ₉ and R ₁₀ each represent a methyl group or an ethyl group, and Y ₂ represents an alkylene group having 1 to 4 carbon atoms.)

(R ₁₁ in 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 any one of claims 1 to 10 in a container.   An ink jet recording apparatus comprising at least ink jetting means for jetting an ink according to any one of claims 1 to 10 and printing an image.   An ink jet recording method comprising at least an ink jetting step of printing an image by flying the ink according to any one of claims 1 to 10.   An ink recorded matter comprising an image recorded by the ink according to any one of claims 1 to 10 on a recording medium.

Images