JP2014034640A - Ink for ink jet recording and cartridge using the same, recording device, image forming method and image formed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink for ink jet recording, excellent in discharge stability, high temperature storage stability and scratch resistance, having high image density and inhibiting device dirt, and to provide a cartridge for ink jet using the same, a recording device for ink jet, an image forming method and an image formed matter.SOLUTION: An ink for ink jet recording contains at least color materials, a polyaniline compound (for example, polyaniline represented by the general formula (1), where R represents a hydrogen atom or a methoxy group, and m represents an integer of 1 to 30) and water as ink components. The ink is accommodated in a container to make the cartridge 200 for ink jet arranged in a recording device for ink jet, is discharged from heads by ink flight means and recorded on an image substrate to obtain an image formed matter.

Description

  The present invention relates to an ink jet recording ink, an ink jet cartridge using the same, an ink jet recording apparatus, an image forming method, and an image formed article.

  The inkjet recording method is easy to make full color because the process is simpler than other recording methods, and there is an advantage that a high-resolution image can be obtained even with an apparatus having a simple configuration. Inkjet recording methods can be broadly divided into continuous and on-demand methods. Among continuous methods, charge control ink jet printers can generate ink droplets and control the direction of flight. The conductivity must be set to an appropriate range.

  In some cases, an on-demand method such as a piezo method or a thermal ink-jet method is performed by measuring the remaining amount of ink by measuring the conductivity. Usually, surfactants and dyes added to the ink are ionized in the ink and show a certain degree of conductivity. However, this is not sufficient, and it is necessary to add a conductive agent to give higher conductivity.

Usually, the pigment-based ink depends on the type of pigment and / or pigment dispersant used, but the electrical conductivity is mostly less than 0.1 mS / cm. In order to adjust the electric conductivity to about ˜5.0 mS / cm, it is necessary to add an ionic surfactant or so-called conductive agent such as an inorganic salt or an organic salt.
Excessive addition of a general ionic surfactant is not preferable because it easily causes foaming of the ink, and the ink is not soaked into the receiving paper, causing bleeding and a decrease in image density. Therefore, the addition of the conductive agent is generally used to adjust the electrical conductivity of the ink. However, the addition to the pigment-based ink tends to hinder dispersion stability such as dispersion and destruction of the pigment. Aggregation of pigment fine particles due to inhibition of dispersion stability and increase in particle size are factors that cause clogging of the head, which is the orifice part of the ink flying means.

  Conventionally, various studies and proposals have been made to add a so-called conductive agent to an ink composition in order to impart conductivity to the ink or generate charge (see, for example, Patent Documents 1 to 15). However, if only the conductive agent described in these patent documents is used, the ink tends to aggregate and clog easily, and the ejection stability and high-temperature storage stability are not sufficient.

As described above, in charge control type inkjet printers, good droplet generation and flight direction control with appropriate conductivity are performed, and in on-demand type inkjet printers, the remaining amount of ink is detected. In order to measure by conductivity, it is necessary to increase conductivity by adding a conductive agent to the ink. However, when a conductive agent is added to pigment-based inks, pigment fine particles aggregate due to pigment dispersion failure, which increases the particle size and causes clogging of the head. Sex could not be maintained sufficiently.
An object of the present invention is to solve the conventional problems and achieve the following objects. That is, an inkjet recording ink having excellent ejection stability and high-temperature storage stability, high image density, excellent scratch resistance, and suppressed device contamination (encoder contamination), and an inkjet cartridge containing the ink It is an object of the present invention to provide an ink jet recording apparatus that performs recording using the ink, an image forming method that performs recording using the ink jet recording apparatus, and an image formed product recorded by the image forming method.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using a polyaniline compound as a conductive agent to be added to the ink composition, leading to the present invention.
That is, the above-mentioned problem is solved by an ink jet recording ink characterized in that it contains at least a coloring material, a polyaniline compound, and water as ink components.
The above-described problem is solved by an ink jet cartridge characterized in that the ink jet recording ink according to any one of claims 1 to 8 is contained in a container.
Further, the above-mentioned problem is achieved by an ink jet recording apparatus comprising ink flying means for recording on an image support by discharging the ink jet recording ink according to any one of claims 1 to 8 from a head. Solved.
Further, the above-mentioned problem is solved by an image forming method characterized in that recording is performed on an image support by discharging ink jet recording ink from a head by the ink flying means of the ink jet recording apparatus according to claim 10. The
Further, the above-mentioned problems are solved by an image formed product recorded on an image support by the image forming method according to claim 11.

  The ink composition of the present invention is composed of at least a coloring material, a polyaniline compound, and water, so that it has excellent ejection stability and high-temperature storage stability, high image density, excellent scratch resistance, and device contamination. An ink jet recording ink in which (encoder dirt) is suppressed is provided, and by using the ink, an ink jet cartridge, an ink jet recording apparatus, an image forming method, and a high image quality capable of stable image formation, As well as an image formed article.

1 is a perspective view of an ink jet recording apparatus in a state where a cover of an ink cartridge loading unit according to the present invention is opened. It is sectional drawing explaining the whole structure of the inkjet recording device of FIG. FIG. 6 is a schematic diagram illustrating an example of an ink bag 241 of an ink cartridge according to the present invention. FIG. 4 is a schematic view showing an ink cartridge 200 in which the ink bag 241 of FIG. 3 is accommodated in a cartridge case 244.

As described above, the ink jet recording ink according to the present invention is characterized by containing at least a coloring material, a polyaniline compound, and water as ink components.
Hereinafter, “ink-jet recording ink” may be abbreviated as “recording ink” or “ink”.

Hereinafter, the present invention will be described in more detail.
The polyaniline compound includes a six-membered ring (benzene ring: aromatic ring), an imine nitrogen atom (= N-) and an amine nitrogen atom (-NH-) for bonding the polymer molecule main chain, It is a conductive polymer.
In other words, the inclusion of a conductive agent composed of a polyaniline compound as an ink component of an inkjet recording ink exhibits the effects described below, and ensures the dispersion stability of the pigment, which has been a problem in particular in pigment-based inks. Ink ejection stability and high-temperature storage stability from the head of the recording apparatus (constituting part of the ink flying means) are improved, and when an image is formed on an image support (recording medium), the image density is high, and the It is excellent in scratching property and suppresses device contamination such as encoder contamination (mist adhesion).
The “polyaniline compound” is sometimes abbreviated as “polyaniline”. In the present invention, forming an image may be referred to as “recording” or “printing”.

Conventionally, materials used as a conductive agent for inkjet recording inks include various inorganic salts and salts of organic compounds.
Specific examples of the inorganic salt include sodium chloride, lithium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium chloride, sodium bromide, lithium bromide, potassium bromide, magnesium bromide, calcium bromide, ammonium bromide, Alkali metals and alkaline earth metals such as lithium iodide, sodium iodide, potassium iodide, magnesium iodide, calcium iodide, ammonium iodide, and ammonia halides, lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, nitric acid Nitrate such as calcium, ammonium nitrate, iron nitrate, copper nitrate, silver nitrate, zinc nitrate, sulfur such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, ammonium sulfate, iron sulfate, copper sulfate, silver sulfate, zinc sulfate Salts, salts thiocyanate and the like.
Specific examples of organic compound salts include choline, monoethanolamine, diethanolamine, triethanolamine, morpholine, sulfates, hydrochlorides, nitrates, phosphates, formates, borates, etc. of various other amines. Further, monomethylammonium chloride, dimethylammonium chloride, trimethylammonium chloride, tetramethyleneammonium chloride, monoethylammonium chloride, ammonium acetate, lithium acetate, sodium acetate, polyoxyethylene and / or sodium salt of acetic acid having an alkyl group, lithium Examples are salts, lithium formate, sodium formate, ammonium formate, tetramethylammonium bromide, tetraethylammonium bromide, sodium salts of sulfosuccinates with alkyl groups, lithium salts, etc. It is.
However, when an inorganic salt or an organic compound salt is added as a conductive agent to a pigment-based ink, problems such as aggregation of pigment fine particles are likely to occur due to inhibition of pigment dispersion stability. Since the diameter increases and clogging of the head of the ink jet recording apparatus occurs, there is a difficulty in ejection stability and high temperature storage stability.

In the present invention, since a polyaniline compound (polyaniline) is used as a conductive agent, the reason is not clear. However, since the polyaniline adsorbs to the colorant (pigment) without hindrance, even when added to a pigment-based ink, Dispersion breakage and the like can be avoided, and the dispersion stability as in the case of the above-described inorganic salts and organic compound salts is not inhibited.
The electrical conductivity of the ink is required to be adjusted to, for example, about 0.10 mS / cm to 1.00 mS / cm. The conductive agent is composed of a water-soluble polyaniline compound in the ink composition of the present invention. The content of is not generally limited by the type of polyaniline, but is adjusted to about 0.05 wt% to 5.0 wt% in the ink composition as described later. With such an added amount, there is no problem in the characteristics required for the ink, and various characteristics can be achieved in a balanced manner.

  As the polyaniline compound, polyaniline represented by the following general formula (1) is preferably used.

  (In the formula, R represents a hydrogen atom or a methoxy group, and m represents an integer of 1 or more and 30 or less.)

  That is, as represented by the general formula (1), a polymer containing a sulfonic acid group in polyaniline is preferably used in the present invention because it has high conductivity and solubility in water or an organic solvent. By introducing a sulfone group as a functional group into a six-membered ring (benzene ring: aromatic ring), it becomes soluble in water or an organic solvent and can be easily mixed in an ink vehicle composed of various ink components. Further, by using polyaniline, which is a polymer, the odor that becomes a problem in conventional low molecular weight amines typified by choline and the like is reduced, and environmental problems are also solved.

As a polyaniline having a large introduction ratio of a sulfonic acid group to an aromatic ring, for example, an aniline copolymer sulfonated product proposed in Japanese Patent Laid-Open No. 5-178989 is known. This sulfonated aniline copolymer exhibits high conductivity and good solubility in water and alcohol solvents.
In the synthesis of this aniline copolymer sulfonated product, various compounds conventionally proposed by using compounds having an alkoxy group on the aromatic ring of aminobenzenesulfonic acid, that is, alkoxy group-substituted aminobenzenesulfonic acids, as monomers are used. The sulfonation operation can be omitted.
The polyaniline compound represented by the general formula (1) in the present invention can be synthesized by the same process. For example, at least one compound selected from aniline, N-alkylaniline and phenylenediamines ( The weight ratio of A) to the alkoxy group-substituted aminobenzenesulfonic acid (B) is changed and copolymerized with an oxidizing agent (for example, ammonium persulfate) in a solution at a temperature of −5 ° C. to 70 ° C. It can be obtained by adjusting the repetition number m of (1) to 1 or more and 30 or less. The resulting polyaniline is a water-soluble and organic solvent-soluble and conductive polymer. The conductivity of the polymer is, for example, about 10 ⁵ Ω / □ to 10 ⁷ Ω / □ although it depends on the introduction ratio of the sulfone group.

The conductivity of the inkjet recording ink is preferably 0.10 mS / cm or more and 1.00 mS / cm or less. If the conductivity is less than 0.10 mS / cm, the conductivity is insufficient. For example, it may be difficult to detect the remaining amount of ink. On the other hand, if the conductivity is more than 1.00 mS / cm, salting out, agglomeration, etc. with a conductive agent may occur. Adverse effects tend to be significant.
The conductivity of the ink depends on the amount of polyaniline compound (polyaniline) added, but the detailed adjustment is carried out by centrifugation, ultrafiltration, SUS mesh, cellulose filtration or the like.

  The content of the polyaniline compound (polyaniline) is preferably 0.05% by weight or more and 5.0% by weight or less in the ink composition. If the polyaniline content is less than 0.05% by weight, the conductivity required for the ink cannot be ensured. On the other hand, if the polyaniline content is more than 5.0% by weight, salting out or aggregation tends to occur.

Either a dye or a pigment can be used as the color material included in the ink composition of the present invention.
<dye>
As the dye used in the present invention, an acid dye, basic dye, direct dye, food coloring, disperse dye, reactive dye, and the like can be used.
<Pigment>
As the pigment used in the present invention, any of a self-dispersing pigment in which an ionic substituent is chemically bonded, a pigment coated with a resin, and a pigment dispersed with a dispersant other than the self-dispersing pigment can be used.
A pigment is preferably used as the colorant. By using the pigment, an ink having excellent water resistance and weather resistance can be obtained.

  Examples of the black pigment include self-dispersing carbon black and carbon black produced by a furnace method or a channel method.

  Examples of yellow pigments include Pigment Yellow 1, Pigment Yellow 2, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, Pigment Yellow 16, Pigment Yellow 17, Pigment Yellow 73, Pigment Yellow 74, Pigment Yellow 75, Pigment Yellow 83, Pigment Yellow 93, Pigment Yellow 95, Pigment Yellow 97, Pigment Yellow 98, Pigment Yellow 114, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 129, Pigment Yellow 138, Pigment Yellow 150, Pigment Yellow 151, Pigment Yellow 154 Pigment Yellow 155, Pigment Yellow 180, etc. It is.

  Examples of magenta pigments include Pigment Red 5, Pigment Red 7, Pigment Red 12, Pigment Red 48 (Ca), Pigment Red 48 (Mn), Pigment Red 57 (Ca), Pigment Red 57: 1, Pigment Red 112, and Pigment Red. 122, Pigment Red 123, Pigment Red 168, Pigment Red 184, Pigment Red 202, Pigment Violet 19, and the like.

  Examples of cyan pigments include Pigment Blue 1, Pigment Blue 2, Pigment Blue 3, Pigment Blue 15, Pigment Blue 15: 3, Pigment Blue 15: 4, Pigment Blue 16, Pigment Blue 22, Pigment Blue 60, Bat Blue 4, Bat Blue 60 etc. are mentioned.

  In addition, by using carbon black as the black pigment, pigment yellow 74 as the yellow pigment, pigment red 122 as the magenta pigment, and pigment blue 15 as the cyan pigment, it is possible to obtain a balanced ink with excellent color tone and light resistance. .

  The ink composition in the ink jet recording ink of the present invention preferably further comprises an organic solvent. The boiling point of the organic solvent is preferably 180 ° C. or higher. That is, when the organic solvent is contained in the ink (aqueous pigment ink), the water retention and wettability of the ink composition can be ensured. As a result, even when the water-based pigment ink is stored for a long period of time, there is no aggregation of the coloring material or increase in viscosity, and excellent storage stability can be realized. Further, an ink for ink jet recording that can maintain the fluidity of ink exposed to a dry state for a long time even when left in an open state at a nozzle tip or the like of an ink jet printer can be realized. Further, nozzle clogging does not occur during printing or when restarting after interruption of printing, and high ejection stability can be obtained.

  Examples of the organic solvent include ethylene glycol, diethylene glycol, 3-methyl-1.3-butyl glycol, 1.3-butyl glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5-pentanediol, and 1,6- Polyhydric alcohols such as quinanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol , Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether Polyhydric alcohol alkyl ethers, ethylene glycol monophenyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monobenzyl ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, Nitrogen-containing heterocyclic compounds such as 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone; amides such as formamide, N-methylformamide, N, N-dimethylformamide; monoethanolamine, diethanolamine, triethanol Examples include amines such as amine, monoethylamine, diethylamine, and triethylamine, sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol, propylene carbonate, and ethylene carbonate.

  The organic solvent (wetting agent) can be used alone or in combination of two or more. Among the wetting agents, containing 3-methyl-1.3-butyl glycol, 1.3-butyl glycol, diethylene glycol, triethylene glycol and / or glycerin prevents clogging due to drying of the ink, that is, prevention of poor ink ejection characteristics due to water evaporation. In addition, an excellent effect can be obtained in improving the formed image of the present invention.

It is preferable that a resin is further contained as an ink composition in the ink jet recording ink of the present invention. As such a resin, a urethane resin is preferably used. The urethane resin may be referred to as “urethane resin” or “polyurethane”.
The urethane-based resin (urethane resin: polyurethane) used in the present invention refers to a polymer composed mainly of a polyurethane skeleton having a main chain of continuous urethane bonds.
In the present invention, among urethane resins, a urethane resin having good water dispersibility (abbreviated as “water dispersible urethane resin”) is used. As such a water-dispersible urethane resin, one having a hydrophilic functional group or a binding component necessary for stable dispersion in water in the main chain of the polyurethane skeleton is used, or an external emulsifier is used. It is common to use an aqueous dispersion of polyurethane obtained by dispersing using a self-dispersion type (self-emulsifying type) with a hydrophilic component in the main chain (self-emulsifying type) Polyurethane) is more preferred.

  The urethane resin used in the present invention is a reaction between a diisocyanate compound, a diol compound such as polyether diols, polyester diols, and polycarbonate diols, and an acid group-containing diol such as a carboxylic acid group and a sulfonic acid group. Various water-dispersible urethane resins (ester urethane resin, ether urethane resin, carbonate urethane resin, etc.) obtained in the above are suitable. Among these, an anionic self-emulsifying ether urethane resin (anionic self-emulsifying ether polyurethane) is more preferable.

  Examples of the diisocyanate include aliphatic diisocyanate compounds such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 1,4-cyclohexane diisocyanate, and 4,4′-. Cycloaliphatic diisocyanate compounds such as dicyclohexylmethane diisocyanate, aromatic aliphatic diisocyanate compounds such as xylylene diisocyanate and tetramethylxylene diisocyanate, aromatic diisocyanate compounds such as toluylene diisocyanate and phenylmethane diisocyanate, modified products of these diisocyanates (carbodiimide, uretdione) Ureitomine-containing metamorphs, etc.).

  Examples of the diol compound include polyether diols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and polyhexamethylene ether glycol, polyethylene adipate, polybutylene adipate, polyneopentyl adipate, and poly-3-methylpentyl. Examples thereof include polyester diols such as adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate, polylactone diols such as polycaprolactone diol, and polycarbonate diol.

  From the viewpoint of ink storage stability, polyether-based, polyester-based, and polycarbonate-based diol compounds are preferable, polyether-based or polycarbonate-based compounds are more preferable, and polyether-based compounds are more preferable. Polyether-based and polycarbonate-based materials are not easily altered by hydrolysis in water, so that the storage stability is improved.

  Examples of the acid group-containing diol such as carboxylic acid group and sulfonic acid group include dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, and dimethylolbutyric acid. Particularly preferred is dimethylolbutanoic acid.

  As a method for synthesizing a urethane resin, so-called water-dispersible urethane resin (water-based urethane resin), an isocyanate-terminated prepolymer is synthesized in a low boiling point solvent (acetone or the like) that does not react with an isocyanate group, and is hydrophilic with a diamine or a polyol. After introducing the group, it is diluted with water to cause phase change, the solvent is distilled off to obtain a polyurethane dispersion, and an isocyanate group-terminated prepolymer having a hydrophilic group introduced is first synthesized and dispersed in water. A prepolymer method in which chain extension is performed with an amine, a hot melt method, a method in which a urethane prepolymer is used as a chain extender in an aqueous emulsifier solution, or liberation obtained from a hydrophobic polyol and an aromatic polyisocyanate. Sulfonating aromatic ring of urethane prepolymer having isocyanate group How through the degree or method using block isocyanate,, known variously both applicable, it is not particularly limited.

  In particular, a urethane-based resin may be synthesized by a prepolymer method, and in this case, a low-molecular weight polyhydroxy compound may be used. Examples of the low molecular weight polyhydroxy compound include glycol and alkylene oxide low molar adducts mentioned as raw materials for the above polyester diols, trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, and alkylene oxide low molar adducts thereof. Is mentioned.

In the case of an aqueous urethane resin, a method is generally known in which a urethane prepolymer prepared in an organic solvent phase is phase-inverted and emulsified and further chain-extended in the aqueous phase. In this case, polyamines such as diamine are generally used as chain extenders. Specifically, the urethane prepolymer is subjected to water extension, or diamine or triamine extension after neutralizing or neutralizing acid groups derived from dimethylolalkanoic acid. Examples of polyamines used as a chain extender during amine extension usually include diamines and triamines. Specific examples thereof include hexamethylene diamine, isophorone diamine, hydrazine, piperazine and the like.
However, it has been found that when a urethane-based resin using polyamines is used as a chain extender, the storage stability of the recording liquid (ink) tends to be poor. This is because an amine-extended urethane resin (polyurethane containing a polyurethane urea moiety) is prone to hydrolysis, and polyamines generated by hydrolysis also act as a flocculant in the pigment dispersion recording liquid. It is presumed to have a bad influence on

  The urethane resin can be used in the form of an alkali metal salt such as Li, Na, or K, an organic amine salt such as ammonia, dimethylamine, or (mono, di, tri) ethanolamine. These can be obtained by further neutralizing the urethane resin obtained by the above-mentioned method. The base used in this neutralization can be appropriately selected according to the counter ion of the desired salt, for example, alkylamines such as butylamine and triethylamine, monoethanolamine, diethanolamine, triethanolamine and the like. Inorganic bases such as alkanolamine, morpholine, ammonia, sodium hydroxide and the like can be mentioned.

  A commercially available resin emulsion can be used as the water-dispersible urethane resin (water-based urethane resin). Examples of such commercially available resin emulsions include SF460, SF460S, SF420SF110, SF300, SF361 (polyurethane resin emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), W-6020, W-5025, W-5661, W-6010 (polyurethane) Resin emulsion, manufactured by Mitsui Chemicals, Inc.).

  The acid value of the anionic self-emulsifying ether polyurethane is preferably 40 or more and 100 or less. When the acid value is less than 40, the ink storage stability is deteriorated, and when the acid value exceeds 100, the viscosity is increased and the ejection stability is deteriorated.

As the ink composition of the present invention, a penetrant can be added. As such penetrants, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene glycol ester, polyoxyethylene / polyoxypropylene decyl ether or acetylene surfactant, silicone surfactant and fluorine-based surfactant Nonionic surfactants such as surfactants may be mentioned.
In the present invention, the following surfactants may be used in combination as long as they do not affect the ink characteristics. Specifically, BT series (Nikko Chemicals), Nonipol series (Sanyo Kasei), D-, P-series (Takemoto Yushi), Surfynol series (Air Products), Olphin series (Nisshin Chemical), EMALEX DAPE Examples include series (Nippon Emulsion), silicone surfactants (Toray Dow Corning, etc.), fluorine surfactants (Neos, Sumitomo 3M, Dupont, Daikin), etc., which are available as nonionic surfactants.

The method for producing the inkjet recording ink of the present invention is not limited, but is usually performed as follows.
First, a vehicle [component A] composed of water and a water-soluble organic solvent (wetting agent, penetrant, etc.) is prepared.
Next, after premixing a mixture of a coloring material (for example, a pigment) and a nonionic dispersant, an anionic surfactant, water or a water-soluble organic solvent, if necessary, with a stirring blade, a homogenizer, or a beadless disperser The pigment dispersion is prepared by dispersing with a known disperser such as a sand mill, a ball mill, a dyno mill, a roll mill, a nanomizer, or a homogenizer. After mixing polyurethane (for example, water-based urethane resin) with the prepared pigment dispersion, a polyaniline compound is added and mixed [component B]. If other materials are mixed before mixing the pigment dispersion and polyurethane (for example, water-based urethane resin), agglomeration or thickening may occur, so the method of mixing the pigment dispersion and polyurethane first is desirable. . When the coloring material is a dye, it is not necessary to prepare a dispersion as in the case of a pigment, and it can be mixed directly.

As described above, the method for producing the inkjet recording ink of the present invention is preferably a method in which a material (ink composition) necessary for the ink is mixed with the pigment dispersion. In this case, the mixing order can be either a method of feeding the ink material into the pigment dispersion or a method of feeding the dispersion into the ink material. An increase in particle diameter can be suppressed, which is preferable.
That is, water-soluble organic solvent, 2-ethyl-1,3-hexanediol, polyoxyethylene (3) alkyl (C13) ether sodium acetate, 2-pyrrolidone, polyether-modified silicone oil, water, etc. do not have a particle size Prepared by mixing and preparing the materials in the above order for about 30 minutes (vehicle A), and mixing and preparing materials having particle sizes such as pigment dispersion and polyurethane in the order shown for about 30 minutes (coloring material B) Then, the colorant B is added to the prepared vehicle A, and the ink is prepared by stirring and mixing for about 1 hour.
In addition, if the pigment dispersion and / or ink is filtered with a filter, a centrifugal separator or the like to remove coarse particles, the ejection stability of the ink can be reliably ensured.

If the ink jet recording ink of the present invention is contained in a container, an ink jet cartridge can be formed (see FIGS. 3 and 4 described later).
An image formed product can be obtained by installing an ink cartridge in an ink jet apparatus, ejecting ink from an orifice (head) according to a recording signal, and recording on an image support (recording medium).

The ink jet recording apparatus of the present invention is characterized by comprising an ink flying means for recording on an image support (recording medium) by discharging the ink jet recording ink of the present invention from a head.
The image forming method of the present invention is characterized in that recording is performed on an image support (recording medium) by ejecting the ink jet recording ink of the present invention from the head by the ink flying means of the ink jet recording apparatus of the present invention. It is what.
Examples of means for printing using the inkjet recording ink (for example, pigment ink) of the present invention include a printing method using an inkjet printer (inkjet printer) having a continuous jet type or on-demand type recording head. . Note that examples of the on-demand type include a piezo method, a thermal ink jet method, and an electrostatic method.
In the formation of the ink cartridge and the formation of the ink jet apparatus, a known technique in this technical field can be appropriately employed without departing from the gist of the present invention (for example, those described in Japanese Patent Application Laid-Open No. 2000-198958) ).

The image-formed product of the present invention is recorded on an image support (recording medium) by the image-forming method of the present invention.
Further, in the present invention, the image support (recording medium) is one that has an absorptivity with respect to the ink composition (such as paper) and one that is substantially non-absorbable with respect to the ink composition (such as a film). Any of these are preferably used.
Specific examples of recording media to which the ink jet recording method according to the present invention can be applied include, for example, plastic sheets based on polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polysulfone, ABS resin, polyvinyl chloride, brass, iron, High-temperature recording materials such as aluminum, SUS, copper, or other metal surfaces, or recording media that have been subjected to metal coating by vapor deposition or other techniques, recording media that has been subjected to water-repellent treatment using paper as a base material, and inorganic materials at high temperatures And a recording medium made of a so-called ceramic material, which is fired in the above. Of these, paper is most preferable in terms of economy and image naturalness.

[Inkjet recording apparatus]
The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording system, such as an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like.
The outline of the ink jet recording apparatus used in the examples will be described below.
FIG. 1 is a perspective view of an ink jet recording apparatus in a state where a cover of an ink cartridge loading unit according to the present invention is opened.
The ink jet recording apparatus shown in FIG. 1 has an apparatus main body (101), a paper feed tray (102) for loading paper mounted on the apparatus main body (101), and an image mounted on the apparatus main body (101). A paper discharge tray (103) for stocking the formed paper and an ink cartridge loading section (104) are provided. On the upper surface of the ink cartridge loading section (104), an operation section (105) such as operation keys and a display is arranged. The ink cartridge loading unit (104) has an openable / closable front cover (115) for attaching and detaching the ink cartridge (200). Reference numeral (111) is the upper cover, and (112) is the front surface of the front cover.

  In the apparatus main body (101), as shown in FIG. 2, a carriage (133) is mainly composed of a guide rod (131) and a stay (132) which are guide members horizontally mounted on left and right side plates (not shown). It is slidably held in the scanning direction and moved and scanned by a main scanning motor (not shown).

  The carriage (133) includes a plurality of recording heads (134) including four inkjet recording heads that discharge ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed downward.

  As an inkjet recording head constituting the recording head (134), a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a temperature change A shape memory alloy actuator using a metal phase change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used.

  The carriage (133) is equipped with a sub tank (135) for each color for supplying ink of each color to the recording head (134). The sub tank (135) is supplied with ink according to the present invention from the ink cartridge (200) of the present invention loaded in the ink cartridge loading section (104) via an ink supply tube (not shown) and replenished. The

  On the other hand, as a paper feeding unit for feeding the paper (142) stacked on the paper stacking unit (pressure plate) (141) of the paper feed tray (102), 1 sheet (142) is fed from the paper stacking unit (141). Opposite to the half-moon roller [sheet feeding roller (143)] for separating and feeding one sheet at a time, and the sheet feeding roller (143), a separation pad (144) made of a material having a large friction coefficient is provided, and this separation pad (144) is It is biased toward the paper feed roller (143).

  A conveying belt (151) for electrostatically adsorbing and conveying the paper (142) as a conveying unit for conveying the paper (142) fed from the paper feeding unit below the recording head (134). A counter roller (152) for conveying the paper (142) sent from the paper supply unit via the guide (145) between the conveying belt (151) and a paper (substantially vertically upward) ( 142) and a leading guide roller 153 urged toward the conveying belt (151) by the holding member (154). (155) and a charging roller (156) which is a charging means for charging the surface of the conveyor belt (151).

  The conveyance belt (151) is an endless belt, is stretched between the conveyance roller (157) and the tension roller (158), and can circulate in the belt conveyance direction. The transport belt (151) includes, for example, a surface layer serving as a sheet adsorbing surface formed of a resin material having a thickness of about 40 μm without resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), It has the same material as the surface layer and a back layer (medium resistance layer, earth layer) that has been subjected to resistance control by carbon. On the back side of the conveyance belt (151), a guide member (161) is arranged corresponding to the printing area by the recording head (134). As a paper discharge unit for discharging the paper (142) recorded by the recording head (134), a separation claw (171) for separating the paper (142) from the transport belt (151), and paper discharge A roller (172) and a paper discharge roller (173) are provided, and a paper discharge tray (103) is arranged below the paper discharge roller (172).

  A double-sided paper feeding unit (181) is detachably attached to the back surface of the apparatus main body (101). The double-sided paper feeding unit (181) takes in the paper (142) returned by the reverse rotation of the transport belt (151), reverses it, and feeds the paper again between the counter roller (152) and the transport belt (151). To do. A manual paper feed unit (182) is provided on the upper surface of the double-sided paper feed unit (181).

In this ink jet recording apparatus, the sheet (142) is separated and fed one by one from the sheet feeding unit, and the sheet (142) fed substantially vertically upward is guided by the guide (145) and the transport belt (151). ) And the counter roller (152). Further, the leading end is guided by the conveying guide (153) and pressed against the conveying belt (151) by the leading end pressure roller (155), and the conveying direction is changed by about 90 °.
At this time, the conveyance belt (157) is charged by the charging roller (156), and the paper (142) is electrostatically adsorbed to the conveyance belt (151) and conveyed. Therefore, by driving the recording head (134) according to the image signal while moving the carriage (133), ink droplets are ejected onto the stopped sheet (142) to record one line, and the sheet ( 142), the next line is recorded after a predetermined amount is conveyed.
Upon receiving a recording end signal or a signal that the rear end of the paper (142) has reached the recording area, the recording operation is finished and the paper (142) is discharged to the paper discharge tray (103).
When a near-end ink remaining amount in the sub tank (135) is detected, a required amount of ink is supplied from the ink cartridge (200) to the sub tank (135).

In this ink jet recording apparatus, when the ink in the ink cartridge (200) is used up, the casing of the ink cartridge (200) can be disassembled and only the ink bag inside can be replaced. Further, the ink cartridge (200) can supply ink stably even when the ink cartridge (200) is vertically placed and has a front loading configuration. Therefore, even when the upper part of the apparatus main body (101) is closed and installed, for example, even when it is stored in a rack or an object is placed on the upper surface of the apparatus main body (101), the ink The cartridge (200) can be easily replaced.
Here, an example is described in which the present invention is applied to a serial (shuttle type) ink jet recording apparatus that is scanned by a carriage.

[ink cartridge]
The ink of the present invention can constitute each color ink such as three primary colors (yellow, magenta, cyan) and black (black) which enable full color display. Each color ink can be stored in a container as an ink set and used as an ink cartridge. The container and / or the ink cartridge may be further provided with other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, the container has an ink bag formed of an aluminum laminate film, a resin film, etc. Etc. are preferable.
The ink cartridge will be described with reference to FIGS. Here, FIG. 3 is a schematic diagram illustrating an example of the ink bag 241 of the ink cartridge of the present invention, and FIG. 4 is a schematic diagram illustrating the ink cartridge 200 in which the ink bag 241 of FIG. 3 is accommodated in the cartridge case 244. is there.

As shown in FIG. 3, ink is filled into the ink bag 241 from the ink inlet 242 and air remaining in the ink bag is exhausted, and then the ink inlet 242 is closed by fusion. In use, the needle of the apparatus main body is pierced into the ink discharge port 243 made of a rubber member and supplied to the apparatus. The ink bag 241 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 4, it is usually housed in a plastic cartridge case 244 and used as an ink cartridge 200 detachably mounted on various ink jet recording apparatuses.
The ink cartridge of the present invention is particularly preferably used by being detachably mounted on the above-described ink jet recording apparatus of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a present Example. In addition, the number of parts in an Example represents a weight part.

[Examples 1-26] and [Comparative Examples 1-3]
A black pigment dispersion (α) was prepared by mixing the colorant type α shown in Table 1 below, the dispersant type I shown in Table 2 below, and water (high pure water) according to the following basic formulation.
<Black pigment dispersion: basic formula of α>
・ Black pigment (color material type: α) 150 parts ・ Dispersant (dispersant type: I) 10 parts ・ High purity water remaining (total: 1000 parts)

Each colorant type β, γ, δ shown in Table 1 below, Dispersant Type II shown in Table 2 below, and water (high pure water) are mixed according to the following basic formulation, and each pigment dispersion of yellow, magenta, cyan ( β, γ, δ) were prepared.
<Color pigment dispersion: basic formulation of β, γ, δ>
・ Yellow, magenta, and cyan pigments (colorant types: β, γ, δ) 200 parts ・ Dispersant (dispersant type II) 75 parts ・ High purity water remaining (total: 1000 parts)

  In Table 2, the compound represented by General Formula (2) of Dispersant Species II has the following structural formula.

  (In the formula, n represents an integer of 20 or more and 200 or less.)

  Premixing was performed with the basic formulations of the black pigment dispersion α and the color pigment dispersions β, γ, and δ to obtain a mixed slurry. Using a disk type media mill (UAM type Kotobuki Kogyo Co., Ltd.), 0.03 mm zirconia beads, filling rate 70%, circulating speed 6 m / s, liquid temperature 10 ° C. for 20 minutes circulation dispersion (retention time 20 min), The coarse particles were centrifuged at 8000 G for 20 minutes with a centrifuge (Model 7700 manufactured by Kubota Corporation), and then filtered using a filter having a diameter of 1.2 μm.

Next, after preparing each ink in accordance with the following basic ink formulation and the following ink blending method, filtration with a membrane filter having a pore diameter of 0.8 μm and vacuum degassing, Examples (Examples 1 to 26) and Comparative Examples Inkjet recording inks (Comparative Examples 1 to 3) were obtained.
The compositions of the various inks obtained and the ink conductivity are shown in Tables 5 and 6 below. The specific conductivities described in Tables 5 and 6 can be obtained by changing the conditions such as ultrafiltration and centrifugation in the subsequent steps. The conductivity was measured using a digital conductivity meter manufactured by Kyoto Electronics in an environment of 23 ° C. and 50% RH.

<Ink basic formula>
Color material [pigment dispersion (α to δ), color material type (ε to θ)] 4.0 to 10.0 parts first 5.0 water soluble organic solvent (glycerin) second water soluble Organic solvent 1 (1,3-butanediol) 20.0 parts, 2-ethyl-1,3-hexanediol 3.0 parts, 2-pyrrolidone 3.0 parts, polyoxyethylene (3) alkyl (C13) ) Sodium ether acetate 0.5 parts · Urethane resin (af) (Table 3 below) 2.0 parts · Polyaniline compound represented by the above general formula (1) (Table 4 below) 0.5 parts · High purity water remaining (Total: 100 copies)

<Ink preparation method>
First, in accordance with the basic ink formulation described above, the following ink compositions (1) to (6) were mixed and then stirred for 30 minutes to prepare vehicle A.
(1) First water-soluble organic solvent (glycerin)
(2) Second water-soluble organic solvent 1 (1,3-butanediol)
(3) 2-ethyl-1,3-hexanediol (4) polyoxyethylene (3) alkyl (C13) ether sodium acetate (5) 2-pyrrolidone (6) high purity water Next, the following (7) to (9) After mixing the ink components, Color Material B was prepared by stirring for 30 minutes.
(7) Color material [pigment dispersion (α to δ) (pigment, surfactant, high purity water), color material type (ε to θ) (dye)] (Table 1)
(8) Urethane resin (af) (Table 3 below)
(9) Polyaniline compounds represented by the general formula (1) (parts 1 to 5) (table 4 below) and choline nitrate (part 6)
Colorant B was added to vehicle A prepared above, mixed, and stirred for 1 hour to prepare inks (Examples 1 to 26 and Comparative Examples 1 to 3). Tables 5 and 6 below collectively show ink compositions.

<Evaluation of ink>
Each of the inks prepared in Examples 1 to 26 and Comparative Examples 1 to 3 was filled in an ink pack for an ink jet printer IPSiO GX 5000 manufactured by Ricoh Co., Ltd. to prepare each ink cartridge.

  Ink cartridges filled with the inks of Examples 1 to 26 and Comparative Examples 1 to 3 were placed in an ink jet printer IPSiO GX 5000 manufactured by Ricoh Co., Ltd., printed on PPC paper XEROX 4200 manufactured by Xerox Co., Ltd., and the printed image was Xrite. Measured with a densitometer. Further, ejection stability and ink storage stability were also evaluated by the following test methods. The measurement results are shown in Table 7 below.

[Evaluation 1]: Encoder dirt evaluation Inkjet printer IPSiO GX 5000 manufactured by Ricoh Co., Ltd. is placed in a constant temperature and humidity chamber, the environment in the tank is set to a temperature of 32 ° C., and humidity is set to 30% RH. After printing continuously, the printer was put into a pause state in which printing was not performed for 20 minutes. This was repeated 50 times, and after a total of 1,000 sheets were printed, the degree of mist adhesion on the encoder sheet was judged. The evaluation criteria are as follows.
○: No mist adhesion △: Slight mist adhesion ×: Complete mist adhesion [Evaluation 2]: Evaluation of ink storage stability Each ink was sealed in a polyethylene container and stored at 70 ° C. for 2 weeks. The viscosity was measured and evaluated according to the following evaluation criteria based on the rate of change from the initial physical properties.
○: Within 10% Δ: Within 30% ×: Over 50% [Evaluation 3]: Image evaluation (saturation of image, solid density)
The optical density of the solid image portion printed using the ink of each Example and Comparative Example was measured with a spectrocolorimeter (X-Rite 938) and evaluated according to the following evaluation criteria.
Note that the sharpness (saturation) of the following image refers to the distance from the origin on the chromaticity diagram by measuring the color of the solid image of the image sample with an Xrite densitometer and plotting it on the chromaticity diagram. More specifically, (a ² + b ² ) ^{1/2 is referred} to for the a value and b value on the chromaticity diagram.
[Saturation of yellow pigment ink]
○: Saturation of 80 or more Δ: Saturation of 75 or more and less than 80 ×: Saturation of less than 75 [Saturation of magenta pigment ink]
○: Saturation 70 or more △: Saturation 65 or more and less than 70 ×: Saturation 65 or less [Saturation of cyan pigment ink]
○: Saturation 55 or more △: Saturation 50 or more and less than 55 ×: Saturation 50 or less [Black solid density]
○: 1.30 or more Δ: 1.20 or more and less than 1.30 ×: less than 1.20 [Evaluation 4]: Evaluation of ejection stability Inkjet printer IPSiO GX 5000 manufactured by Ricoh Co., Ltd. was placed in a thermostatic chamber. Was set at a temperature of 32 ° C. and a humidity of 30% RH, and after printing the following print pattern charts continuously for 20 sheets, it was put into a resting state in which printing was not performed for 20 minutes, and this was repeated 50 times. After printing the sheet, a nozzle check pattern was struck and judged by the number of omissions.
<Print pattern chart>
In the printing pattern, each ink was printed at a duty of 100% in a chart in which the printing area in the image area is 5% of the printing area of each color in the entire area of the paper. The printing conditions were a recording density of 300 dpi and one-pass printing. The evaluation criteria are as follows.
○: No missing Δ: Less than 10 missing ×: More than 10 missing [Evaluation 5]: Evaluation of scratch resistance A commercially available sand eraser was subjected to 10 times of friction with a weight of 750 g, and the image was peeled before and after the friction. Was observed. The determination was made as follows.
○: No peeling Δ: Partial peeling is observed and visibility is also lowered.
X: Most part peeled

The following was found from the evaluation results shown in Table 7 above.
(1) Examples 1 to 26 comprising the ink composition of the present invention are Comparative Example 1 (not containing a coloring material), Comparative Example 2 (conducting agent: not containing a polyaniline compound), and Comparative Example 3 Compared to (contains choline nitrate as a conductive agent), the characteristics are maintained in a well-balanced manner in any of the encoder stain evaluation, ink storage stability evaluation, image evaluation, ejection stability evaluation, and scratch resistance evaluation. On the other hand, Comparative Examples 1-3 were the characteristics which cannot endure actual use in any of these evaluations. (Claim 1).
(2) Example 5 (average molecular weight 3,000), Example 6 (average molecular weight 20,000) and Example 25 (average molecular weight 30,000) were compared, and Examples 5 and 6 were examples. 25, which is superior in the discharge stability evaluation. This is because Examples 5 and 6 are within the range of the general formula (1) (Claim 2).
When Examples 15 and 16 were compared with Examples 17 and 18, Example 15 (polyaniline compound content: 0.05% by weight) was identical to Example 17 (polyaniline compound content: 0.03% by weight). ) Is superior in encoder stain evaluation, and Example 16 (polyaniline compound content: 5.0% by weight) is superior in Example 18 (polyaniline compound content: 5.2% by weight) in ink storage stability evaluation. It was better than This is because the content of the polyaniline compound represented by the general formula (1) in Examples 15 and 16 is within a preferable range (Claim 3).
(3) When Example 4 was compared with Example 24, Example 4 was superior to Example 24 in ink storage stability evaluation. This is because the resin used in Example 24 is a polycarbonate-based resin, whereas the resin used in Example 4 is an anionic self-emulsifying ether-based polyurethane resin (claim 4).
(4) When Examples 19 and 20 are compared with Examples 21 and 22, Example 19 (oxidation: 45) is better than Example 21 (oxidation: 30) in terms of encoder stain evaluation, ink storage stability evaluation, and abrasion resistance. Example 20 (oxidation: 95) was superior to Example 22 (oxidation: 105) in ink storage stability evaluation. This is because the resin used in Examples 19 and 20 has an acid value of an anionic self-emulsifying ether polyurethane resin within a preferable range (Claim 5).
(5) When Example 1 is compared with Example 23, Example 1 is superior to Example 23 in encoder dirt evaluation and ejection stability evaluation. This is because Example 1 contains an organic solvent (Claim 6).
(6) When Examples 11 and 12 are compared with Examples 13 and 14, Example 11 (conductivity: 0.10 mS / cm) is an encoder than Example 13 (conductivity: 0.05 mS / cm). This is superior in dirt evaluation, and Example 12 (conductivity: 1.00 mS / cm) is superior in Example 14 (conductivity: 1.05 mS / cm) in discharge stability evaluation. This is because the conductivities of Examples 11 and 12 are within a preferable range (Claim 7).
(7) When Examples 2 and 4 are compared with Examples 8 and 9, Example 2 (coloring material type β: pigment) is more effective in evaluating scratch resistance than Example 8 (coloring material type ζ: dye). Example 4 (coloring material type δ: pigment) was superior to Example 9 (coloring material type η: dye) in scuff resistance evaluation. This is because Examples 2 and 4 use pigments (Claim 8).

From the above results, by including at least a coloring material, a polyaniline compound, and water as an ink component, it is possible to achieve both encoder stain evaluation, ink storage stability evaluation, image evaluation, ejection stability evaluation, and scratch resistance evaluation. An ink jet cartridge, an ink jet recording apparatus, an image forming method, and an ink jet recording ink capable of stably forming a high quality image by using such an excellent ink jet recording ink can be provided. An image formation can be provided.
That is, the ink jet recording ink of the present invention is excellent in image quality (high image density) on various image supports (recording media) and has good ejection stability, and therefore can be applied to various recordings by the ink jet recording method. Can do. As the recording apparatus using the ink jet recording method, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like can be applied.

DESCRIPTION OF SYMBOLS 101 Main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading part 105 Operation part 111 Upper cover 112 Front cover front 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Paper stacking part (pressure plate)
142 Paper 143 Feed roller 144 Separation pad 145 Guide 151 Transport belt 152 Counter roller 153 Transport guide 154 Press member 155 Tip pressure roller 156 Charging roller 157 Transport roller 158 Tension roller 161 Guide member 171 Separation claw 172 Discharge roller 173 Discharge Roller 181 Double-sided paper feed unit 182 Manual paper feed unit 200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge case

JP 54-85804 A JP-A-55-50073, JP-A-55-82175, Japanese Patent Laid-Open No. 55-115478 JP 56-36559 A JP 56-161480 A JP-A-57-83569 JP 2002-212470 A JP-A-2005-75998 JP 2006-316227 A JP 2007-297626 A

Claims (13)

  An ink jet recording ink comprising at least a colorant, a polyaniline compound, and water as ink components. The inkjet recording ink according to claim 1, wherein the polyaniline compound is represented by the following general formula (1).

(In the formula, R represents a hydrogen atom or a methoxy group, and m represents an integer of 1 or more and 30 or less.)   The inkjet recording ink according to claim 1 or 2, wherein the content of the polyaniline compound is 0.05% by weight or more and 5.0% by weight or less in the ink composition.   The inkjet recording ink according to claim 1, further comprising a resin as the ink composition, wherein the resin is an anionic self-emulsifying ether-based polyurethane.   The ink-jet recording ink according to claim 4, wherein an acid value of the ether polyurethane resin is 40 or more and 100 or less.   6. The ink jet recording ink according to claim 1, further comprising an organic solvent as the ink composition.   The ink jet recording ink according to any one of claims 1 to 6, wherein the ink jet recording ink has a conductivity of 0.10 mS / cm or more and 1.00 mS / cm or less.   8. The inkjet recording ink according to claim 1, wherein the color material is a pigment.   An ink jet cartridge, wherein the ink jet recording ink according to claim 1 is contained in a container.   An ink jet recording apparatus comprising ink jetting means for recording on an image support by discharging the ink jet recording ink according to claim 1 from a head.   11. An image forming method comprising: recording on an image support by ejecting ink jet recording ink from a head by the ink flying means of the ink jet recording apparatus according to claim 10.   An image formed article recorded on an image support by the image forming method according to claim 11.   The image-formed product according to claim 12, wherein the image support is paper.

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