JP2006291174A - Water-based ink, ink cartridge, ink recorded product, ink jet recording device and ink jet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water based ink capable of giving high quality images with less bleeding and excellent in scratching properties for both regular and coated sheets of paper, particularly for a glossy sheet of paper and an OHP sheet of paper, an ink cartridge storing the water based ink, ink recorded products using the water based ink, an ink jet recording device and ink jet recording method using the water based ink. <P>SOLUTION: The water based ink contains a pigment as a coloring material having at least one hydrophilic group on its surface and exhibiting a water dispersibility in the absence of a dispersing agent, and a guanidine derivative. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is suitable for ink jet recording such as an on-demand method such as a piezo method and a thermal method, and a continuous jet method such as a charge control method, and exhibits excellent scratch properties with respect to plain paper. Water-based ink that is excellent in scratching and capable of forming a high-quality image with little bleeding, an ink jet recording method using the water-based ink, an ink cartridge containing the water-based ink, and an ink jet loaded with the water-based ink The present invention relates to a recording apparatus and an ink recorded matter formed with the water-based ink.

  An ink jet recording apparatus that discharges liquid ink from a nozzle or the like and records on a recording medium such as paper, cloth, or film is small and inexpensive, and is non-contact with the recording medium. Various types of paper and other materials can be used, color recording is possible, and because they have advantages such as quietness, they are widely used in homes, schools, workplaces, etc.

  In recent years, many full-color inkjet printers capable of performing full-color recording as well as black single-color inkjet printers capable of obtaining good print quality on plain paper such as report paper, copy paper, and recycled paper are commercially available. The full-color ink jet printer is also required to have high quality when printed on plain paper, in particular, high image quality (no blurring of the image, etc.) and high color development.

On the other hand, in order to obtain an image with high image quality (no blurring of the image and the like) and higher color development than that of plain paper, there are printing applications on coated paper such as coated paper and glossy paper, OHP sheets, and the like. In the case of these coated papers, the colorant tends to stay in the vicinity of the surface to suppress bleeding of the image and achieve high color development. However, since the colorant tends to stay near the surface, it may be peeled off by rubbing with a finger, clothes, eraser, or marking pen, or spread on the paper surface (hereinafter these phenomena are collectively referred to as rubbing). was there.
As described above, it is required to improve the rubbing property as well as achieving both high image quality (no blurring of the image) and high color development on plain paper and coated paper.

  Conventionally, various ink compositions have been proposed for preventing the bleeding of the image. That is, use of glycol ethers as a wetting agent (for example, see Patent Document 1), use of a water-soluble organic solvent (for example, see Patent Document 2), and use of a dye dissolution accelerator (for example, see Patent Document 3) The proposal is known.

  Further, recently, fastness of an image is also required, and a coloring material using a pigment instead of a dye has been proposed. By using the pigment, water resistance is improved. There has been proposed an ink that uses a pigment as a coloring material and uses glycol ethers to improve image bleeding (see, for example, Patent Document 4). However, as a problem when using a pigment ink, there is a problem that pigment particles are likely to aggregate with respect to long-term storage stability, which is generally inferior to dye ink. In addition, there is a problem that the rubability with the coated paper is poor.

As a technique for improving the dispersion stability of pigment particles, a method of modifying the pigment particle surface, for example, a method of azo coupling a substituent containing a water-solubilizing group to carbon black (see, for example, Patent Document 5) A method of polymerizing a water-soluble monomer or the like on the surface of carbon black (for example, see Patent Document 6) and a method of oxidizing carbon black (for example, see Patent Document 7) are known.
Furthermore, there is known an ink that has improved image bleeding by using a combination of the surface-modified pigment and glycol ethers (see, for example, Patent Document 8).

  However, an ink jet recording ink that has good long-term storage stability, good print quality, and excellent scratch resistance on coated paper has yet to be developed.

  In such a situation, the applicant firstly improved the image drying property, water resistance, light resistance, resolution, sharpness, sharpness, etc., and further increased the image density after printing and clogging of the nozzles. In order to prevent the ink composition, the ink composition is attached to the recording medium before the ink composition is attached to the recording medium, and then the ink composition is attached to the place where the liquid composition is attached. In a recording method (hereinafter, such a method is referred to as a two-component system), the liquid composition contains a guanidine derivative, and the ink composition contains a dye having an anionic group as a coloring material. An ink jet recording method was proposed (see Patent Document 9). According to this proposal, the above-mentioned problems can be solved. However, since the liquid composition is attached in addition to the ink composition, an extra ink flying means (head) is required, resulting in an increase in cost and a large apparatus. There are problems such as complicated means and cost increase and printing processing time.

  Similarly, as a method using a two-component ink, a fixing solution containing a precipitant such as polyguanidine and an ink containing a self-dispersing pigment and a polyurethane binder are printed on a porous medium substrate such as alumina. Dilution comprising a system (see Patent Document 10) and a condensed polyamine type new aqueous cationic polymer compound having a cyclic base derived from a guanidine group having a specific structural formula in the dilution liquid and ink Liquids (see Patent Documents 11 and 12) have been proposed. These proposals also have problems such as an extra ink flying means (head) requiring an increase in cost, an increase in apparatus, a complicated control means, an increase in cost, and a long print processing time.

Japanese Patent Publication No.2-2907 Japanese Patent Publication No. 1-15542 JP-B-2-3837 Japanese Patent No. 3102304 Japanese Patent No. 3510897 Japanese Patent Laid-Open No. 8-81646 Japanese Patent No. 3405817 Japanese Patent Laid-Open No. 10-95941 JP 2003-237218 A Japanese Patent Laid-Open No. 2005-1387 JP 2000-289323 A JP 2000-290562 A

This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past, and to achieve the following objectives.
That is, the present invention exhibits excellent scratch properties with respect to plain paper, and also has excellent scratch properties with respect to coated paper, especially glossy paper and OHP sheets, and has high image quality with little bleeding. Water-based ink, an ink-jet recording method using the water-based ink, an ink cartridge containing the water-based ink, an ink-jet recording apparatus loaded with the water-based ink, and an ink record formed by the water-based ink are provided. Objective.

  The present inventors have studied an ink that does not impair the stability of the ink even if it contains the guanidine derivative that has been effective for the above-described problems when used in a two-component system. Although it is difficult to ensure the stability of the ink when the guanidine derivative is directly contained in the ink with the pigment or dye used, it has at least one hydrophilic group on the surface of the pigment and in the absence of a dispersant. By including a guanidine derivative in an ink using a pigment exhibiting water dispersibility, it is possible to maintain an aqueous ink having excellent scratch resistance on a recording medium after printing, by maintaining the stability of the ink. The headline and the present invention were completed.

  Although the reason for this is not clear, the guanidine derivative and the pigment exist stably in the ink, and after printing on a recording medium, the amino group in the guanidine derivative and the hydrophilic group on the surface of the pigment are combined. Thus, it is presumed that an insoluble or hardly soluble salt is formed in the solvent, and an image excellent in abrasion is obtained.

That is, the said subject is solved by following (1)-(18) of this invention.
(1) “The coloring material is a pigment, and has a pigment having at least one hydrophilic group on the surface of the pigment and exhibiting water dispersibility in the absence of a dispersant, and a guanidine derivative. Water-based ink ";
(2) “Aqueous ink according to (1) above, wherein the guanidine derivative is an inorganic acid salt or organic acid salt of guanidine”;
(3) “Aqueous ink according to (1) above, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of aminoguanidine”;
(4) “The water-based ink according to (1) above, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of diphenylguanidine or triphenylguanidine”;
(5) "Aqueous ink according to (1) above, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of a bisguanidine compound";
(6) "Aqueous ink according to (1) above, wherein the guanidine derivative is an inorganic acid salt or organic acid salt of polyalkylene guanidine";
(7) “Aqueous ink according to any one of (1) to (6) above, wherein the content of the guanidine derivative is 0.1 to 1000 ppm”;
(8) “Aqueous ink according to (7) above, wherein the content of the guanidine derivative is 1 to 100 ppm”;
(9) “Aqueous ink according to any one of (1) to (8) above, which contains a water-soluble organic solvent”;
(10) As described in (9) above, wherein the water-soluble organic solvent is at least one selected from glycerin, diethylene glycol, 1,3-butanediol, triethylene glycol and 2-pyrrolidone. Aqueous ink ";
(11) Any one of (1) to (10) above, wherein the hydrophilic group on the surface of the pigment is at least one selected from a carboxyl group, a sulfone group, a carbonyl group, and a hydroxyl group A water-based ink according to claim 1;
(12) "Aqueous ink according to any of (1) to (11) above, wherein the pigment has an average particle size of 10 to 200 nm";
(13) “Aqueous ink according to any one of (1) to (12) above, which is at least one selected from cyan ink, magenta ink, yellow ink, and black ink”;
(14) In the inkjet recording method using a plurality of inks selected from cyan ink, magenta ink, yellow ink and black ink, the ink according to (13) is used as at least one of them. An inkjet recording method characterized by:
(15) “An ink jet recording method including at least an ink flying step of applying a stimulus to water-based ink and causing the water-based ink to fly to form an image, wherein the water-based ink includes any one of (1) to (13). An ink jet recording method comprising using the water-based ink according to claim 1;
(16) “Ink cartridge comprising the water-based ink according to any one of (1) to (13) contained in a container”;
(17) An inkjet recording apparatus including at least an ink flying unit that applies an stimulus to the aqueous ink according to any one of (1) to (13) and causes the aqueous ink to fly to form an image. An inkjet recording apparatus comprising the aqueous ink according to any one of (1) to (13) as the aqueous ink ”;
(18) An “ink recorded matter comprising an image formed using the water-based ink according to any one of (1) to (13) on a recording medium”.

The present invention has the effects described below.
According to the water-based ink of the first aspect, the following effects can be obtained.
It is difficult to ensure the stability of the ink when a guanidine derivative is directly contained in the ink with a pigment or dye using a normal dispersant, but at least one pigment has a hydrophilic group on the surface of the pigment. A water-based ink that can maintain its stability as an ink by containing a guanidine derivative in an ink using a pigment that exhibits water dispersibility in the absence of water and has excellent scratching properties on a recording medium after printing. Can be provided.

  According to the water-based inks of claims 2 to 6, by using the guanidine derivatives described in the respective items, the ink can maintain more stability and has an excellent scratch property on a recording medium after printing. Ink can be provided.

  According to the water-based inks of claims 7 to 8, by setting the content of the guanidine derivative within this range, it is possible to provide a water-based ink having sufficient scratch resistance and excellent long-term storage stability of the ink.

  According to the water-based ink of claim 9, when the water-based ink contains a water-soluble organic solvent and is made of an aqueous medium, the water-based ink having an excellent effect of preventing clogging of the nozzle portion can be provided.

  According to the water-based ink of claim 10, since the water-soluble organic solvent according to claim 10 is used in the water-based ink, the compatibility with the guanidine derivative and the dispersion stability of the pigment are excellent. Water-based ink that can further improve the effect of preventing clogging of the portion can be provided. In addition, a preferable water-based ink can be provided from the viewpoint of safety and price.

  According to the water-based ink of claim 11, by using a surface-modified pigment in which the hydrophilic group on the surface of the pigment is a carboxyl group, a sulfone group, a carbonyl group or a hydroxyl group, the image can be further reduced at a higher image density. It is possible to provide an ink capable of forming an extremely high-quality image with less bleeding and less bleeding. Such an ink does not cause phase separation, and does not cause aggregation or thickening. Therefore, the ink is suitable for use in a recording method in which an image can be formed on a recording medium by ejecting and flying as a droplet from a fine ejection port. .

  According to the water-based ink of claim 12, when the average particle diameter of the pigment is 10 to 200 nm, the dispersion stability is excellent, and thus the storage stability and the ejection stability in the ink jet recording method are excellent, and the image is exposed through. An excellent water-based ink with less ink can be provided.

  According to the aqueous ink of the thirteenth aspect, as the ink composition, an aqueous ink excellent in scratching property selected from yellow ink, magenta ink, cyan ink and black ink can be provided.

  According to the ink jet recording method of claim 14, a plurality of inks selected from yellow ink, magenta ink, cyan ink and black ink are used in combination as an ink composition, so that a color image having excellent scratching properties can be obtained. An inkjet recording method that can be formed can be provided.

  According to the fifteenth aspect, by using the water-based ink described above, it is possible to form an image having excellent scratch resistance, no phase separation, no aggregation or thickening, and the like as droplets from a fine discharge port. It is possible to provide an ink jet recording method capable of forming an image on a recording medium by discharging and flying.

According to claims 16 to 17, an ink cartridge containing an aqueous ink having excellent image characteristics capable of forming an image excellent in scratching property, not causing phase separation, and causing no aggregation or thickening, and the like An ink jet recording apparatus loaded with water-based ink or provided with the cartridge can be provided.
Furthermore, according to the eighteenth aspect, it is possible to provide an ink recorded matter having excellent scratch resistance.

  That is, the water-based ink of the present invention is particularly preferably used in an ink jet recording method in which a water-based ink is ejected and ejected as droplets from a fine ejection port to form a color image on a recording medium. It can be widely used as ink for general writing instruments such as ballpoint pens, recorders, and pen plotters.

The present invention is described in detail below.
As described above, the ink of the present invention contains a guanidine derivative.
The guanidine derivative used in the present invention is the following compound and its inorganic acid salt or organic acid salt.

<Specific examples of guanidine compounds>
A guanidine compound is a compound having the following skeleton structure and an inorganic acid salt or an organic acid salt thereof.

ここで、Ｒ_１とＲ_２とＲ_３は、水素、炭素数１〜４のアルキル基、アルキレン基、炭素数１〜４のアルキル基又はアルコキシ基が置換された置換フェニル基又は非置換フェニル基を示し、Ｒ_１又はＲ_２がアルキレン基の場合そのアルキレン基を挟んで同一の骨格を有するビス体或いはポリ体を含む。なお、ビス体、ポリ体の具体例は後記する。
このグアニジン化合物の具体例としては、
（１）グアニジンの無機酸塩又は有機酸塩、例えば、硫酸グアニジン、塩酸グアニジン、リン酸グアニジン、硝酸グアニジン、炭酸グアニジン、酢酸グアニジン、チオシアン酸グアニジン、スルファミン酸グアニジン等。
（２）アミノグアニジンの無機酸塩又は有機酸塩、例えば、硫酸アミノグアニジン、塩酸アミノグアニジン、リン酸アミノグアニジン、硝酸アミノグアニジン、炭酸アミノグアニジン、酢酸アミノグアニジン、チオシアン酸アミノグアニジン、スルファミン酸アミノグアニジン等。
（３）Ｎ，Ｎ’−ジフェニルグアニジン、Ｎ，Ｎ’−ジ−ｏ−トリルグアニジン、Ｎ，Ｎ’，Ｎ”−トリフェニルグアニジンの硫酸塩、塩酸塩、リン酸塩、硝酸塩、酢酸塩、炭酸塩、チオシアン酸塩及びスルファミン酸塩等。

Here, R ₁ , R ₂ and R ₃ are hydrogen, a substituted or unsubstituted phenyl group substituted with an alkyl group having 1 to 4 carbon atoms, an alkylene group, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. In the case where R ₁ or R ₂ is an alkylene group, it includes a bis body or a poly body having the same skeleton with the alkylene group in between. Specific examples of the bis body and the poly body will be described later.
As a specific example of this guanidine compound,
(1) Inorganic or organic acid salts of guanidine, such as guanidine sulfate, guanidine hydrochloride, guanidine phosphate, guanidine nitrate, guanidine carbonate, guanidine acetate, guanidine thiocyanate, guanidine sulfamate and the like.
(2) Aminoguanidine inorganic acid salt or organic acid salt, for example, aminoguanidine sulfate, aminoguanidine hydrochloride, aminoguanidine phosphate, aminoguanidine nitrate, aminoguanidine carbonate, aminoguanidine acetate, aminoguanidine thiocyanate, aminoguanidine sulfamate etc.
(3) N, N′-diphenylguanidine, N, N′-di-o-tolylguanidine, N, N ′, N ″ -triphenylguanidine sulfate, hydrochloride, phosphate, nitrate, acetate, Carbonate, thiocyanate, sulfamate and the like.

<Specific examples of bisguanidine compounds>
Sulfates, hydrochlorides, phosphates, nitrates, acetates, carbonates, thiocyanates and sulfamates of bisguanidine compounds represented by the following exemplary compounds.

・・・例示化合物１

... Exemplary compound 1

・・・例示化合物２

... Exemplary compound 2

・・・例示化合物３

... Exemplary compound 3

・・・例示化合物４

... Exemplary compound 4

・・・例示化合物５

... Exemplary compound 5

・・・例示化合物６

... Exemplary compound 6

<Specific examples of polyalkylene guanidine>
An inorganic acid salt or organic acid salt of polyalkyleneguanidine represented by the following general formula.

（式中、ｎは３〜５００の整数、ｍは２〜６の整数を示す。）
・・・例示化合物７

(In the formula, n represents an integer of 3 to 500, and m represents an integer of 2 to 6.)
... Exemplary compound 7

In the aqueous ink of the present invention, the content of such a guanidine derivative in the ink is not particularly limited, but is preferably 0.1 to 1000 ppm, more preferably 1 to 100 ppm.
If it is less than 0.1 ppm, sufficient scratch resistance cannot be obtained, and if it is more than 1000 ppm, the ink may have poor long-term storage stability.

  The pigment used in the present invention is a self-dispersing pigment in which the pigment in the ink is surface-modified and at least one hydrophilic group is directly bonded to the surface of the pigment and exhibits water dispersibility in the absence of a dispersant.

  Since the self-dispersing pigment has a modified surface and the hydrophilic group is present on the surface, the self-dispersing pigment can be dispersed in water even in the absence of a dispersant. An ink using the self-dispersing pigment as a colorant Even if it contains a guanidine derivative, it is excellent in dispersibility and dispersion stability in the water-based ink, excellent in storage stability, ejection stability (eg, intermittent ejection stability), and redispersibility after drying. Even if printing is stopped for a long time and the water content of the ink near the nozzles of the head evaporates, clogging does not occur, and high-quality printing or images can be easily obtained by simple cleaning. It is possible to improve the scratching property of the recorded matter after recording.

The hydrophilic group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polar group or atomic group having a strong interaction with water, and specifically, —SO _{3 H, -SO 3 M, -OSO} 3 H, -OSO 3 M, -COOM, -COOH, -NR 3 X, -NH 2, -OH, -CN, and the like (provided that the R is Represents an alkyl group, M represents an alkali metal or —NH ₄ , and X represents a halogen atom). Among these, a carboxyl group, a sulfone group, a carbonyl group, or a hydroxyl group is preferable in terms of dispersion stability and water resistance of an image after printing. Among them, the type having a carboxyl group bonded has the same effect as a pigment dispersed with a dispersant having a carboxyl group bonded, thereby improving the water resistance of the recording medium after printing and obtaining a sufficient drying speed. And is more preferable from the effect of preventing back-through.

  For example, the pigment is subjected to surface modification treatment such as acid treatment, base treatment, coupling agent treatment, polymer graft treatment, plasma treatment or oxidation or reduction treatment on the pigment particle surface. Self-dispersible pigments having a hydrophilic group such as a group, a sulfone group, a carbonyl group or a hydroxyl group can be produced. By performing such a surface treatment, the water-containing hydrophilic group is contained more than a normal pigment, and self-dispersion becomes possible. Among these treatment methods, a method of coupling and bonding a diazonium salt having a hydrophilic group capable of various chemical modifications to the pigment particle surface is preferable. This manufacturing method can be carried out by the method described in JP-T-10-510862.

  As the self-dispersible pigment of the present invention, a commercially available self-dispersible pigment can be used as it is. Examples of such commercially available pigments include CAB-O-JET-200, CAB-O-JET-300, IJX-55 (above, manufactured by Cabot Specialty Chemicals, Inc.), Microjet Black CW as black pigments. -1 (manufactured by Orient Chemical Co., Ltd.), LIOJET WD BLACK 002C (manufactured by Toyo Ink Co., Ltd.), etc., CAB-O-JET-250C as a cyan pigment, CAB-O-JET-260M as a magenta pigment, yellow Examples of the pigment include CAB-O-JET-270Y (manufactured by Cabot Specialty Chemicals, Inc.).

There is no restriction | limiting in particular in the average particle diameter of the said pigment, Although it can select suitably according to the objective, 10-200 nm is preferable and 20-150 nm is more preferable. When the average particle diameter is less than 10 nm, the pigment as the colorant penetrates deep into the paper, and thus the image density may be low and the back-through may be increased, and the dispersion stability in the ink may be increased. The image density may be lowered during printing. If it exceeds 200 nm, the fixing property of the image is inferior, the dispersion stability is poor, the particle size becomes large due to aggregation or the like during long-term storage, and clogging may easily occur.
Since the pigment is not dissolved in the ink and dispersed as particles compared to the dye, it is difficult for the ink to penetrate deep into the paper even if the ink has the same penetration characteristics. It is possible to obtain a small and good image quality.

  Here, the average particle diameter is determined based on the amount of change in the frequency (light frequency) of the light (backscattered light) returning from the particle when the particle performing Brownian motion in the ink is irradiated with laser light. The volume cumulative percentage measured by the dynamic light scattering method (Doppler scattered light analysis) for obtaining the diameter is a value of 50%.

  In addition to the above self-dispersing pigment as a colorant, pigments and dyes using other dispersion methods may be added as long as the content does not cause problems due to reaction with a guanidine derivative. The guanidine derivative is used by dissolving in an ink, and the ink preferably contains a water-soluble organic solvent from the viewpoint of preventing clogging of the nozzle portion.

  Examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, 1,3-butanediol, 2,3- Butanediol, 1,4-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,6-hexanediol, glycerin, 1,2,6-hexanetriol, 1,2, Polyhydric alcohols such as 4-butanetriol, 1,2,3-butanetriol, and petriol;

  Polyhydric alcohol alkyl ethers such as 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, triethylene glycol monomethyl ether;

  Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether;

Nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone;

Amides such as formamide, N-methylformamide, N, N-dimethylformamide; amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine; dimethyl sulfoxide, sulfolane, thiodiethanol, thiodiglycol Sulfur-containing compounds such as
Propylene carbonate, ethylene carbonate and the like. These solvents are used alone or in combination with water.

  Among these, in particular, from the point of compatibility with the guanidine derivative and excellent dispersion stability of the pigment, for example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, tetraethylene glycol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, Polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, thiodiglycol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3- Dimethyl-2-imidazolidinone is preferred Arbitrariness.

  Among these, glycerin, diethylene glycol, 1,3-butanediol, triethylene glycol, and 2-pyrrolidone are particularly preferable from the viewpoints of safety and price.

  When 2-pyrrolidone is added to the ink, an excellent effect is obtained in improving the image density and preventing the back-through. This is because by containing 2-pyrrolidone, the ink easily spreads and spreads on the paper surface, and the permeation in the thickness direction of the paper is relatively suppressed, so that the colorant tends to stay near the paper surface. It is estimated that.

  The amount of the water-soluble organic solvent added is preferably from 3 to 70% by mass, more preferably from 5 to 45% by mass, based on the entire aqueous ink. When the addition amount is less than 3% by mass, the effect of suppressing water evaporation in the ink is insufficient, and depending on the content of the guanidine derivative and the pigment in the ink, the effect as a dissolution aid becomes insufficient. In some cases, the storage stability and ejection stability of the ink are impaired. On the other hand, if it exceeds 70% by mass, the jetting stability in the ink jet due to the increase in viscosity may be inferior, and cockling of the image area after printing may be deteriorated.

  In order to promote solubility of the guanidine derivative in the ink, the number of carbon atoms of 1 to 4 such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, etc. It is also possible to add alkyl alcohols, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone and diacetone alcohol, keto alcohols, and the like.

  The ink is required to dry quickly after being applied to the recording medium, particularly when printing is performed at a high speed. In order to satisfy this requirement, the water-based ink of the present invention preferably contains a compound for increasing the permeability of the ink into the recording medium.

  Examples of compounds (penetrating agents) for increasing the permeability include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkyl sorbitan esters, polyoxyethylene Nonionic surfactants such as alkylamines, glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene glycol fatty acid esters; alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene Anionic surfactants such as alkyl ether acetates, alkylbenzene sulfonates, N-acyl amino acid salts, alkylsulfosuccinates, alkyl phosphates; Cationic surfactants such as quaternary amines such as corium salts; fluorinated surfactants such as perfluoroalkyl phosphates, perfluoroalkyl carboxylates, perfluoroalkyl betaines, etc. .

  Among these, more specific and preferred penetrants are diethylene glycol monobutyl ether, diethylene glycol monophenyl ether, propylene glycol monobutyl ether, and a fluorosurfactant, which have a large effect of increasing permeability.

  The amount of the penetrant added to the ink is particularly preferably an amount that makes the surface tension of the ink 50 mN / m or less. The amount of penetrant added to the ink should be selected in such a range that the surface tension is too low to make printing impossible, image bleeding occurs, and the dot diameter does not become too large. As the surface tension, it is desirable to add the penetrant in an amount that is in the range of 30 to 50 mN / m. Therefore, although it varies somewhat depending on the type of penetrant used, it is 30% by mass or less, preferably 0.001 to 30% by mass, and more preferably 0.000% by mass relative to the entire aqueous ink. About 1 to 15% by mass is appropriate.

  In addition to the above, what can be added to the ink can be used in the same manner as that conventionally added to the ink used in the ordinary ink jet recording method. For example, there are a viscosity modifier, an antiseptic (including an antiseptic agent), a pH adjuster, and an ultraviolet absorber.

  As the viscosity modifier, the above-mentioned water-soluble organic solvent is used, and as the viscosity modifier other than the water-soluble organic solvent, it is desirable that these viscosity modifiers can dissolve guanidine derivatives well. , Triethylene glycol and glycerin are preferably used.

  Examples of preservatives include dehydroacetate, sorbate, benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, 2,4-dimethyl-6-acetoxy-m-dioxane, 1,2 -A compound such as benzthiazolin-3-one.

  pH adjusters include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali carbonates such as sodium carbonate and potassium carbonate, ammonium hydroxide, quaternary ammonium hydroxide, diethanolamine, triethanolamine, etc. It is done. Further, salts such as sodium phosphate and sodium oxalate can be added to obtain pH buffering properties. The pH value of the ink should be determined in consideration of the fact that the guanidine derivative used does not cause precipitation, the ink does not immerse the member in contact with the ink, and the like. You must select a value. Therefore, the pH value of the ink containing the guanidine derivative is preferably 3 to 13, and more preferably 5 to 12.

Other physical properties of the water-based ink of the present invention are not particularly limited. For example, the viscosity and conductivity are preferably in the following ranges.
As a viscosity, 2-20 mPa * s is preferable at 25 degreeC, and 3-10 mPa * s is more preferable. If the viscosity is less than 2 mPa · s, bleeding may occur in the image, and if it exceeds 20 mPa · s, it may be difficult to ensure ejection stability.

  As said electrical conductivity, 0.5 S / m or less is preferable, for example, and 0.005-0.4 S / m is more preferable.

  There is no restriction | limiting in particular as coloring of the water-based ink of this invention, According to the objective, it can select suitably, A cyan ink, a magenta ink, a yellow ink, a black ink, etc. are mentioned. In addition, when recording is performed using a plurality of inks selected from cyan ink, magenta ink, yellow ink, and black ink, a multicolor image can be formed, and an ink set using all colors is used. When recording is performed, a full-color image can be formed. However, when a plurality of colored inks are used, it is not necessary to use the ink of the present invention for all the inks, and the ink may be used only for the ink for which scratch resistance is desired to be improved. For example, when only black ink is pigment ink and color ink is dye ink, a method of using the ink of the present invention only for black ink may be used.

  The ink of the present invention is excellent in scratching and has no high-quality images, high color development, ejection stability, and is less likely to cause ejection failure due to bubble entrainment during printing or when printing is stopped. Even if it occurs, an ink that can maintain reliability can be obtained with a simple recovery mechanism, so that it can be applied to a high-speed recording process that has been difficult in general. That is, in a recording method for forming an image on a recording medium by ejecting and ejecting a plurality of ink droplets from the same or different ejection ports so that at least a part of the pixel area overlaps on the recording medium, the overlapping is performed on the recording medium. It is possible to shorten the difference between the ejection times of the two ink droplets that cause the ink droplets, so that very high-speed recording is possible. In recent years, the technology related to inkjet printers has made remarkable progress and the printing speed has been improved, but in order to maintain a certain level of high image quality, dots that are adjacent to each other have not been formed continuously, while one is in the paper. The other ink was not landed until it soaked into the ink. That is, it can be said that high-quality printing is achieved while sacrificing printing speed by a method called so-called multi-pass printing.

Since the water-based ink of the present invention exhibits very high penetrability, it has become possible to perform high-quality printing in a single pass that could not be achieved conventionally. Furthermore, high-quality printing can be achieved without sacrificing printing speed even in color printing of four or more colors by the line head. Further, it is possible to record on a recording medium having a problem of abrasion such as coated paper, particularly glossy paper, OHP sheet, etc. in the high-speed recording process.
The water-based ink of the present invention is particularly preferably used in an ink jet recording method in which a water-based ink is ejected and ejected as droplets from a fine ejection port to form a color image on a recording medium. It can also be used as an ink for general writing instruments, recorders, and pen plotters. The water-based ink of the present invention is not limited to the above uses.

  As a suitable method for recording using the water-based ink of the present invention, a piezoelectric element is used as a pressure generating means for pressurizing the ink in the ink flow path, and the diaphragm that forms the wall surface of the ink flow path is deformed. A so-called piezo-type device that changes the volume of the ink flow path to eject ink droplets (see Japanese Patent Application Laid-Open No. 2-51734), or a bubble generated by heating ink in the ink flow path using a heating resistor A so-called thermal type (see Japanese Patent Application Laid-Open No. 61-59911), and an electrostatic force generated between the diaphragm and the electrode by disposing the diaphragm and the electrode that form the wall surface of the ink channel opposite to each other. The diaphragm is deformed by the electrostatic type to change the volume of the ink flow path to eject ink droplets (see Japanese Patent Laid-Open No. 6-71882), and the television set proposed by Mr. Keiji Maeda The method also performs various recorded emissions Journal 37 (7) 540 (1983) have been described. As a typical method, a charge control type continuous injection method; an on-demand method such as a Kaiser type, a Gould type, a bubble jet (registered trademark) type, a stem type type or the like can be cited. The water-based ink of the present invention can be favorably used in a printer equipped with any of these inkjet heads.

  The water-based ink of the present invention can be suitably used in various fields, and can be suitably used in an image forming apparatus (printer or the like) based on an ink jet recording method. An ink cartridge, an ink recorded matter, an ink jet recording apparatus, and an ink jet recording method of the present invention described below can be used for a printer or the like having a function of heating aqueous ink at 50 to 200 ° C. to promote print fixing. It can be particularly preferably used.

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

  Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 shows an external perspective view of the ink cartridge before loading into the recording apparatus, and FIG. 2 shows a front sectional view of the ink cartridge.

  As shown in FIG. 2, the ink cartridge (7) includes an ink absorber (42) that absorbs a predetermined color of ink in a cartridge body (41). The cartridge body (41) is formed by adhering or welding an upper lid member (44) to an upper opening of a case (43) having a wide opening at the upper portion, and is made of, for example, a resin molded product. The ink absorber (42) is made of a porous material such as a urethane foam, and after being compressed and inserted into the cartridge body (41), the ink is absorbed.

  An ink supply port (45) for supplying ink to the recording head (6) is formed at the bottom of the case (43) of the cartridge body (41), and a seal ring (45) is formed on the inner peripheral surface of the ink supply port (45). 46). The upper lid member (44) has an air opening (47). The cartridge main body (41) is closed with the ink supply port (45) in a state before loading, and the case (43) with pressure applied to the wide side wall during handling of the cartridge during loading or transportation, or during vacuum packaging. ) Is compressed and deformed, and the cap member (50) is attached to prevent the internal ink from leaking.

Further, as shown in FIG. 1, the air opening (47) is sealed by sticking a film-like sealing member (55) having an oxygen permeability of 100 ml / m ² or more to the upper lid member (44). In this way, the air opening (47) is sealed with the sealing member (55) having an oxygen permeability of 100 ml / m ² or more, so that the ink cartridge (7) is made of a packaging member such as a non-permeable aluminum laminate film. By wrapping in a reduced pressure state, gas is contained in the ink due to the atmosphere in the space (A) (see FIG. 2) that is created between the ink absorber (42) and the cartridge body (41) when the ink is filled. Even when dissolved, the air in the ink is discharged to the space between the packaging member outside the cartridge body (41) having a high degree of vacuum through the seal member (55), and the degree of deaeration of the ink is improved.

  The ink cartridge of the present invention contains the water-based ink (ink set) of the present invention and can be used by being detachably attached to various ink jet recording apparatuses, and can also be attached to and detached from the ink jet recording apparatus of the present invention described later. It is particularly preferable to use it mounted on.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.

The inkjet recording method of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

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

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

  Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, Examples include thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, electrostatic actuators that use electrostatic force, etc. It is done.

  The flying mode of the water-based ink is not particularly limited and varies depending on the type of the stimulus. For example, when the stimulus is “heat”, the water-based ink in the recording head corresponds to the recording signal. A method in which thermal energy is applied using, for example, a thermal head, bubbles are generated in the aqueous ink by the thermal energy, and the aqueous ink is ejected and ejected as droplets from the nozzle holes of the recording head by the pressure of the bubbles. , Etc. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the water-based ink as droplets from the nozzle holes of the recording head.

  The size of the droplet of the water-based ink to be ejected is preferably 3 to 40 pl, for example, and the speed of ejection and ejection is preferably 5 to 20 m / s, and the driving frequency thereof. Is preferably 1 kHz or more, and the resolution is preferably 300 dpi or more.

  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.

  Next, the aqueous ink of the present invention is accommodated in an ink cartridge with reference to the drawings, and the ink cartridge is mounted on an ink jet printer, and ejected and ejected as droplets from fine ejection ports to form an image on a recording medium. A method will be described.

FIG. 3 is a schematic front view of a mechanism part of a serial type ink jet recording apparatus on which an ink cartridge having an ink containing part containing the ink of the present invention is mounted.
The mechanism part of this ink jet recording apparatus lays a main support guide rod (3) and a sub support guide rod (4) between the side plates (1, 2) on both sides in a substantially horizontal positional relationship, and these main support guides. The carriage unit (5) is slidably supported in the main scanning direction by the rod (3) and the secondary support guide rod (4).

  The carriage unit (5) has four heads (6) for ejecting yellow (Y) ink, magenta (M) ink, cyan (C) ink and black (Bk) ink, respectively, and their ejection surfaces (nozzles). The surface (6a) is mounted facing downward, and on the upper side of the head (6) of the carriage unit (5) is an ink supply body of each color for supplying ink to each of the four heads (6). Four ink cartridges (7y, 7m, 7c, 7k) are mounted so as to be replaceable.

  The carriage unit (5) is a timing belt (11) stretched between a drive pulley (drive timing pulley) (9) and a driven pulley (idler pulley) (10) rotated by the main scanning motor (8). The carriage (5), that is, the four heads (6) are moved in the main scanning direction by driving and controlling the main scanning motor (8).

  Further, subframes (13, 14) are erected on the bottom plate (12) connecting the side plates (1, 2), and the paper (16) is placed between the subframes (13, 14) perpendicular to the main scanning direction. A transport roller (15) for feeding in the scanning direction is rotatably held. A sub-scanning motor (17) is disposed on the side of the sub-frame (14), and the rotation of the sub-scanning motor (17) is transmitted to transmit the rotation of the sub-scanning motor (17) to the transport roller (15). A gear (18) fixed to the shaft and a gear (19) fixed to the shaft of the transport roller (15) are provided.

  Further, between the side plate (1) and the sub-frame (12) of the bottom plate, a reliability maintenance / recovery mechanism (hereinafter referred to as “sub-system”) (21) of the head (6) is arranged. The sub-system (21) holds four cap means (22) for capping the ejection surface of each head (6) by a holder (23), and the holder (23) can be swung by a link member (24). The carriage unit (5) is brought into contact with the engaging portion (25) provided in the holder (23) by the movement of the carriage unit (5) in the main scanning direction, so that the carriage unit (5) moves according to the movement of the carriage unit (5). The holder (23) is lifted up, the cap means (22) is used to capping the ejection surface (6a) of the ink jet head (6), and the carriage unit (5) is moved to the printing area side, whereby the carriage unit (5 ), The holder (23) is lifted down so that the cap means (22) is separated from the ejection surface (6a) of the inkjet head (6).

  The cap means (22) is connected to the suction pump (27) via the suction tube (26), and forms an atmosphere opening, and communicates with the atmosphere via the atmosphere opening tube and the atmosphere opening valve. ing. The suction pump (27) discharges the sucked waste liquid to a waste liquid storage tank (not shown) through a drain tube or the like.

  Further, on the side of the holder (23), there is a wiper blade (28) which is a wiping means made of an elastic member such as a fiber member, a foam member or rubber for wiping the discharge surface (6a) of the inkjet head (6). The blade arm (29) is attached to an arm (29) and is pivotally supported so as to be swung by rotation of a cam that is turned by a driving means (not shown).

  Next, FIG. 4 shows an example of the configuration of a recording cartridge (recording unit) provided with an ink containing portion containing the ink of the present invention and a head portion for ejecting ink droplets. The recording unit will be described below.

  The recording unit (30) is of a serial type, and the head (6), an ink tank (33) that stores ink supplied to the head (6), and the inside of the ink tank (33) are sealed. A main part is comprised with a cover member (34).

  A number of nozzles (32) for ejecting ink are formed in the head (6) of the recording unit (30). The ink is guided from the ink tank (33) to a common liquid chamber (not shown) via an ink supply pipe (not shown), and converted into an electric signal from the recording apparatus main body input from the electrode (31). Accordingly, the liquid is discharged from the nozzle (32). This type of recording unit (30) has a structure suitable for a head of a type that can be manufactured at low cost, a head called a thermal method or a bubble method, which uses thermal energy as a driving power source. The ink of the present invention is suitable because it can provide ejection stability and frequency stability even in a recording method such as a bubble method or a thermal method.

Here, the serial type ink jet recording apparatus has been described. However, the ink of the present invention is accumulated by recording the nozzles in an arbitrary arrangement such as a staggered pattern at a density equal to or about a fraction of the target image resolution. The present invention can also be applied to a recording apparatus having a so-called line head arranged more than the width of the medium.
In addition, although it demonstrated in the example applied to the serial type (shuttle type) inkjet recording device which a carriage scans, it can apply similarly to the line type inkjet recording device provided with the line type head.

  Further, the ink jet recording apparatus and the ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method. For example, the ink jet recording apparatus, the facsimile apparatus, the copying apparatus, the printer / fax / copier multifunction machine, etc. It can be particularly preferably applied.

(Recorded material)
The recorded matter recorded by the ink jet recording apparatus and the ink jet recording method of the present invention is the recorded matter of the present invention. The recorded matter of the present invention has an image formed on the recording medium using the water-based ink of the present invention.

The recording medium is not particularly limited and may be appropriately selected according to the purpose. For example, the recording medium that has been conventionally used is not sized or weakly sized, and is generally commercially available as high-quality paper. Processed paper, medium quality paper, Japanese paper, cotton, acetate, nylon and other fibers and fabrics made with those fibers, polyester coated with hydrophilic polymer compounds such as polyvinyl alcohol, polyvinyl pyrrolidone and ethyl cellulose And plastic films such as polycarbonate, plain paper, coated paper such as glossy paper and coated paper, special paper, cloth, film, OHP sheet, and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, the improvement in scratching, which is a feature of the present invention, can be confirmed more remarkably with glossy paper, OHP sheet, and sized paper.

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

Example 1
Preparation of Ink Set The ink set of Example 1 was prepared by combining BK ink, C ink, M ink, and Y ink having the following formulation.
<Preparation of BK ink (black ink)>
Carboxyl group-bonded carbon black dispersion (CAB-O-JET-300, solid content 15% by mass, Cabot Specialty Chemicals Inc., average particle size 128 nm) 33% by mass, carbonate of Exemplified Compound 1 200 ppm, 1 , 3-butanediol 5.0% by mass, glycerin 7.0% by mass, diethylene glycol monobutyl ether 5.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water are sufficiently stirred at room temperature. After that, it was adjusted with a 5% by mass aqueous solution of sodium hydroxide so that the pH was 8.5. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, BK ink was prepared.

<Preparation of C ink (cyan ink)>
Sulfonic acid group-bonded cyan pigment (CAB-O-JET-250C, solid content 10 mass%, manufactured by Cabot Specialty Chemicals Inc., average particle size 79 nm) 40.0 mass%, phosphate of Example Compound 3 50 ppm , Ethylene glycol 4.0% by mass, glycerin 10.0% by mass, diethylene glycol monobutyl ether 6.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water were mixed and stirred. It was adjusted with a 5% by weight aqueous solution of lithium hydroxide so as to be 0.0. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. C ink was prepared by the above.

<Preparation of M ink (magenta ink)>
Sulfonic acid group-bonded magenta pigment (CAB-O-JET-260M, solid content 10% by mass, Cabot Specialty Chemicals Inc., average particle size 112 nm) 35.0% by mass, guanidine nitrate 400 ppm, thiodiglycol 10 After mixing and stirring 0.0 mass%, diethylene glycol monobutyl ether 4.0 mass%, sodium dehydroacetate 0.1 mass% and the remaining amount of ion-exchanged water, 5 mass of lithium hydroxide so that the pH is 8.7. % Aqueous solution. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. M ink was prepared by the above.

<Preparation of Y ink (yellow ink)>
Sulfonic acid group-bonded yellow pigment (CAB-O-JET-270Y, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc., average particle size 133 nm) 45.0% by mass, guanidine carbonate 20 ppm, glycerin 16.0 After mixing and stirring mass%, diethylene glycol monobutyl ether 3.0 mass%, dehydroacetic acid sodium 0.1 mass%, and the remaining amount of ion-exchanged water, an aqueous solution of lithium hydroxide 5 mass% so that the pH becomes 8.3. Adjusted. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. In this way, Y ink was prepared.

(Example 2)
Preparation of Ink Set An ink set of Example 2 was prepared by combining BK ink, C ink, M ink, and Y ink having the following formulation.
<Preparation of BK ink (black ink)>
Sulfonic acid group-bonded carbon black pigment dispersion (CAB-O-JET-200, solid content 20% by mass, Cabot Specialty Chemicals Inc., average particle size 109 nm) 35% by mass, aminoguanidine phosphate 1000 ppm, 2 -After sufficiently stirring 10.0 mass% of pyrrolidone, 14.0 mass% of glycerin, 0.9 mass% of propylene glycol monobutyl ether, 0.1 mass% of dehydroacetate and ion-exchanged water at room temperature, The pH was adjusted with a 5% by weight aqueous lithium hydroxide solution to 9.0. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, BK ink was prepared.

<Preparation of C ink (cyan ink)>
Sulfonic acid group-bonded cyan pigment dispersion (CAB-O-JET-250C, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc., average particle size 79 nm) 40.0% by mass, aminoguanidine hydrochloride 5 ppm, ethylene After mixing and stirring 4.0% by weight of glycol, 14.0% by weight of triethylene glycol, 6.0% by weight of propylene glycol monobutyl ether, 0.1% by weight of sodium dehydroacetate and the remaining amount of ion-exchanged water, the pH was 8 It was adjusted with a 5% by weight aqueous solution of lithium hydroxide so as to be 0.0. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. C ink was prepared by the above.

<Preparation of M ink (magenta ink)>
40.0% by mass of sulfonic acid group-bonded magenta pigment dispersion (CAB-O-JET-260M, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc., average particle size 112 nm), thiocyanic acid of exemplary compound 2 After mixing and stirring 30 ppm of salt, 20.0% by weight of diethylene glycol, 3.0% by weight of propylene glycol monobutyl ether, 0.1% by weight of sodium dehydroacetate and the remaining amount of ion-exchanged water, the pH was adjusted to 8.7. It adjusted with the lithium hydroxide 5 mass% aqueous solution. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. M ink was prepared by the above.

<Preparation of Y ink (yellow ink)>
Sulfonic acid group-bonded yellow pigment dispersion (CAB-O-JET-270Y, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc., average particle size 133 nm) 40.0% by mass, nitrate of exemplified compound 4 0 After mixing and stirring 1 ppm, triethylene glycol 15.0% by mass, glycerin 25.0% by mass, propylene glycol monobutyl ether 6.0% by mass, sodium dehydroacetate 0.1% by mass, and the remaining amount of ion-exchanged water, The pH was adjusted to 7.8 with a 5% by weight aqueous solution of lithium hydroxide. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. In this way, Y ink was prepared.

(Example 3)
Preparation of Ink Set An ink set of Example 2 was prepared by combining BK ink, C ink, M ink, and Y ink having the following formulation.
<Preparation of BK ink (black ink)>
Carboxyl group-bonded carbon black dispersion (Microjet Black CW-1, solid content 20% by mass, manufactured by Orient Chemical Co., Ltd., average particle size 71 nm) 30% by mass, exemplified compound 6 sulfate 2000 ppm, glycerin 25.0% by mass , 2-ethyl-1,3-hexanediol 3.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water were sufficiently stirred at room temperature so that the pH was 9.0. It adjusted with the lithium hydroxide 5 mass% aqueous solution. Then, it filtered with the membrane filter with an average hole diameter of 5.0 micrometers. Thus, BK ink was prepared.

<Preparation of C ink (cyan ink)>
35.0% by mass of sulfonic acid group-bonded cyan pigment dispersion (CAB-O-JET-250C, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc., average particle size 79 nm), acetate of Exemplified Compound 7 80ppm, diethylene glycol 10.0% by mass, triethylene glycol 10.0% by mass, 2-ethyl-1,3-hexanediol 2.0% by mass, sodium dehydroacetate 0.1% by mass and ion-exchanged water balance After stirring, it was adjusted with a 5% by weight aqueous solution of lithium hydroxide so that the pH was 8.0. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. C ink was prepared by the above.

<Preparation of M ink (magenta ink)>
Sulfonic acid group-bonded magenta pigment dispersion (CAB-O-JET-260M, solid content 10 mass%, manufactured by Cabot Specialty Chemicals Inc., average particle size 112 nm) 40.0 mass%, hydrochloride of exemplified compound 5 0.05 ppm, 18.0% by mass of triethylene glycol, 2.0% by mass of 2-pyrrolidone, 1.0% by mass of sodium polyoxyethylene alkyl ether acetate, 0.1% by mass of sodium dehydroacetate and the remaining amount of ion-exchanged water After mixing and stirring, the pH was adjusted to 8.7 with a 5% by weight aqueous solution of lithium hydroxide. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. M ink was prepared by the above.

<Preparation of Y ink (yellow ink)>
Sulfonic acid group-bonded yellow pigment dispersion (CAB-O-JET-270Y, solid content 10% by mass, Cabot Specialty Chemicals Inc., average particle size 133 nm) 40.0% by mass, N, N′-diphenyl Mixing and stirring 400 ppm of guanidine sulfate, 15.0% by weight of diethylene glycol, 5.0% by weight of glycerin, 0.3% by weight of sodium polyoxyethylene alkyl ether acetate, 0.1% by weight of sodium dehydroacetate and the remaining amount of ion-exchanged water Then, the pH was adjusted with a 5% by weight aqueous solution of lithium hydroxide so that the pH was 7.8. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. In this way, Y ink was prepared.

Example 4
Preparation of ink set Except for the guanidine derivative added to the BK, C, M, and Y inks in the ink set of Example 1, respectively, except that the following guanidine derivative was added instead, the same as in Example 1 An ink set of Example 4 was prepared.
BK ink: Acetate of exemplary compound 1 200 ppm
C ink: Phosphate of Exemplified Compound 3 50 ppm
M ink: N, N′-di-o-tolylguanidine carbonate 400 ppm
Y ink: Guanidine thiocyanate 20ppm

(Example 5)
Preparation of ink set Except for the guanidine derivative added to the BK, C, M, and Y inks in the ink set of Example 1, respectively, except that the following guanidine derivative was added instead, the same as in Example 1 An ink set of Example 5 was prepared.
BK ink: Guanidine sulfate 200ppm
C ink: Guanidine hydrochloride 50ppm
M ink: guanidine sulfamate 400ppm
Y ink: Guanidine phosphate 20ppm

(Example 6)
Preparation of ink set Except for the guanidine derivative added to the BK, C, M, and Y inks in the ink set of Example 1, respectively, except that the following guanidine derivative was added instead, the same as in Example 1 An ink set of Example 6 was prepared.
BK ink: Guanidine acetate 200ppm
C ink: N, N ′, N ″ -triphenylguanidine sulfamate
50ppm
M ink: aminoguanidine thiocyanate 400ppm
Y ink: Aminoguanidine bicarbonate 20ppm

(Example 7)
Preparation of Ink Set An ink set of Example 7 was prepared by combining BK ink, C ink, M ink, and Y ink having the following formulation.
<Preparation of BK ink (black ink)>
Carboxyl group-bonded carbon black dispersion (solid content 18% by mass, average particle size 108 nm) 33% by mass, exemplary compound 1 acetate 200 ppm, glycerin 7.0% by mass, diethylene glycol monobutyl ether 5.0% by mass, After 0.1 mass% of sodium dehydroacetate and the remaining amount of ion-exchanged water were sufficiently stirred at room temperature, the pH was adjusted to 8.5 with an aqueous solution of 5 mass% sodium hydroxide. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, BK ink was prepared.

<Preparation of C ink (cyan ink)>
Sulfonic acid group-bonded cyan pigment (CAB-O-JET-250C, solid content 10% by mass, Cabot Specialty Chemicals Inc.) 40.0% by mass, Example Compound 3 phosphate 50 ppm, thiodiglycol 10 After mixing and stirring 0.0% by mass, diethylene glycol monobutyl ether 6.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water, 5% by mass of lithium hydroxide so that the pH is 8.0. % Aqueous solution. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. C ink was prepared by the above.

<Preparation of M ink (magenta ink)>
Sulfonic acid group-bonded magenta pigment (CAB-O-JET-260M, solid content 10% by mass, Cabot Specialty Chemicals Inc.) 35.0% by mass, guanidine nitrate 50 ppm, ethylene glycol 4.0% by mass, glycerin After mixing 10.0% by mass, diethylene glycol monobutyl ether 4.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water, lithium hydroxide 5 was added so that the pH was 8.7. It adjusted with the mass% aqueous solution. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. M ink was prepared by the above.

<Preparation of Y ink (yellow ink)>
Sulfonic acid group-bonded yellow pigment (CAB-O-JET-270Y, solid content 10% by mass, Cabot Specialty Chemicals Inc.) 45.0% by mass, guanidine acetate 20 ppm, glycerin 16.0% by mass, diethylene glycol After mixing and stirring 3.0% by mass of coal monobutyl ether, 0.1% by mass of sodium dehydroacetate and the remaining amount of ion-exchanged water, it was adjusted with a 5% by mass aqueous solution of lithium hydroxide so that the pH was 8.3. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. In this way, Y ink was prepared.

(Example 8)
Preparation of Ink Set An ink set of Example 8 was prepared by combining BK ink, C ink, M ink, and Y ink having the following formulation.
<Preparation of BK ink (black ink)>
Sulfonic acid group-bonded carbon black pigment dispersion (solid content 18% by mass, average particle size 124 nm) 38% by mass, aminoguanidine phosphate 1000 ppm, 2-pyrrolidone 10.0% by mass, glycerin 14.0% by mass, propylene glycol After thoroughly stirring 0.9% by weight of coal monobutyl ether, 0.1% by weight of sodium dehydroacetate and the remaining amount of ion-exchanged water at room temperature, the resulting solution is made into an aqueous solution of 5% by weight of lithium hydroxide so that the pH becomes 9.0. Adjusted. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, BK ink was prepared.

<Preparation of C ink (cyan ink)>
Sulfonic acid group-bonded cyan pigment dispersion (CAB-O-JET-250C, solid content 10 mass%, Cabot Specialty Chemicals Inc.) 40.0 mass%, aminoguanidine hydrochloride 5 ppm, ethylene glycol 4.0 mass %, Triethylene glycol 14.0% by mass, propylene glycol monobutyl ether 6.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of deionized water so that the pH is 8.0. Was adjusted with a 5% by weight aqueous solution of lithium hydroxide. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. C ink was prepared by the above.

<Preparation of M ink (magenta ink)>
Sulfonic acid group-bonded magenta pigment dispersion (CAB-O-JET-260M, solid content 10 mass%, Cabot Specialty Chemicals Inc.) 40.0 mass%, exemplary compound 2 acetate 30 ppm, diethylene glycol 20. After mixing and stirring 0% by mass, propylene glycol monobutyl ether 3.0% by mass, sodium dehydroacetate 0.1% by mass and the remaining amount of ion-exchanged water, 5% by mass of lithium hydroxide so that the pH becomes 8.7. Adjusted with aqueous solution. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. M ink was prepared by the above.

<Preparation of Y ink (yellow ink)>
Sulfonic acid group-bonded yellow pigment dispersion (CAB-O-JET-270Y, solid content 10% by mass, manufactured by Cabot Specialty Chemicals Inc.) 40.0% by mass, Example Compound 4 nitrate 0.1 ppm, triethylene After mixing and stirring 15.0% by weight of glycol, 25.0% by weight of glycerin, 6.0% by weight of propylene glycol monobutyl ether, 0.1% by weight of sodium dehydroacetate and the remaining amount of deionized water, the pH was 7.8. It adjusted with lithium hydroxide 5 mass% aqueous solution so that it might become. Thereafter, filtration was performed with a membrane filter having an average pore diameter of 0.8 μm. In this way, Y ink was prepared.

(Comparative Example 1)
Preparation of ink set Except for the ink set of Example 1, except that the pigment dispersion added to each of the BK, C, M, and Y inks as a colorant was used, but the following water-soluble dye was added instead. In the same manner as in Example 1, an ink set of Comparative Example 1 was prepared.
BK ink: C.I. I. Direct Black 168 5.0% by mass
C ink: C.I. I. Direct Blue 199 4.0% by mass
M ink: C.I. I. Direct Red 227 3.5% by mass
Y ink: C.I. I. Direct Yellow 142 4.5% by mass

(Comparative Example 2)
Preparation of ink set The ink set of Comparative Example 2 was prepared in the same manner as in Example 2 except that the guanidine derivative added to each of the BK, C, M, and Y inks in the ink set of Example 2 was omitted. Prepared.

(Comparative Example 3)
Preparation of ink set In the ink set of Example 3, except for the pigment dispersion added to the BK, C, M, and Y inks as colorants, respectively, instead of being dispersed by the hydrophilic groups on the surface of the pigment. An ink set of Comparative Example 3 was prepared in the same manner as Example 3 except that the following pigment dispersion of a so-called dispersant dispersion type in which the pigment was dispersed by a dispersant instead of the pigment being added.

<Preparation of B ink (black ink)>
A pigment dispersion having an average particle size of 110 nm was prepared by dispersing 15% by mass of carbon black, 3% by mass of a formalin condensate of naphthalene sulfonate, and the remaining amount of ion-exchanged water using a bead mill. 40.0% by mass of this pigment dispersion is added.

<Preparation of C ink (cyan ink)>
C. I. Pigment Blue 15: 3 15% by mass, styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3% by mass, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 88 nm. 23.3 mass% of this pigment dispersion was added.

<Preparation of M ink (magenta ink)>
C. I. Pigment Red 122 15% by mass, styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3% by mass, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 120 nm. 26.7% by mass of this pigment dispersion was added.

<Preparation of Y ink (yellow ink)>
C. I. Pigment Yellow 74 15% by mass, naphthalenesulfonate formalin condensate 3% by mass, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 108 nm. 26.7% by mass of this pigment dispersion was added.

(Comparative Example 4)
Preparation of Ink Set Example 7 except that in the ink set of Example 7, the pigment dispersion added to the BK, C, M, and Y inks as the colorant was added, and the following water-soluble dye was added instead. In the same manner as in Example 7, an ink set of Comparative Example 4 was prepared.
BK ink: C.I. I. Direct Black 168 6.0% by mass
C ink: C.I. I. Direct Blue 199 4.0% by mass
M ink: C.I. I. Direct Red 227 3.5% by mass
Y ink: C.I. I. Direct Yellow 142 4.5% by mass

(Comparative Example 5)
Preparation of ink set The ink set of Comparative Example 5 was prepared in the same manner as in Example 7, except that the guanidine derivative added to each of the BK, C, M, and Y inks in the ink set of Example 7 was removed. Prepared.

(Comparative Example 6)
Preparation of ink set In the ink set of Example 8, except for the pigment dispersion added to each of the BK, C, M, and Y inks as the colorant, instead of being dispersed by the hydrophilic group possessed on the surface of the pigment. An ink set of Comparative Example 3 was prepared in the same manner as Example 8 except that the following pigment dispersion of the so-called dispersant dispersion type in which the pigment was dispersed by a dispersant instead of the pigment being added.

<Preparation of B ink (black ink)>
A pigment dispersion having an average particle size of 110 nm was prepared by dispersing 15% by mass of carbon black, 3% by mass of a formalin condensate of naphthalene sulfonate, and the remaining amount of ion-exchanged water using a bead mill. 26.7% by mass of this pigment dispersion is added.

<Preparation of C ink (cyan ink)>
C. I. Pigment Blue 15: 3 15% by mass, styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3% by mass, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 88 nm. 46.7 mass% of this pigment dispersion was added.

<Preparation of M ink (magenta ink)>
C. I. Pigment Red 122 15% by mass, styrene-acrylate-methacrylic acid diethanolamine salt copolymer 3% by mass, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 172 nm. 26.7% by mass of this pigment dispersion was added.

<Preparation of Y ink (yellow ink)>
C. I. Pigment Yellow 74 (average particle size 174 nm) 15% by weight, naphthalenesulfonate formalin condensate 3% by weight, and the remaining amount of ion-exchanged water were dispersed using a bead mill to prepare a pigment dispersion having an average particle size of 31 nm. . 26.7% by mass of this pigment dispersion was added.

  Next, with respect to each of the obtained inks of Examples and Comparative Examples, initial filling property, recovery property, storage property, scratching property, image sharpness, and show-through were evaluated as follows. The results are shown in Table 1. However, the BK ink and M ink of Comparative Example 1, the BK ink of Comparative Example 3, and the BK ink and M ink of Comparative Example 4 were not evaluated because they had poor initial filling properties.

  The initial filling property, recoverability, and storage property were tested by degassing each ink, filling the cartridge, and loading it into an ink jet printer (IPSiO JET 300, manufactured by Ricoh Co., Ltd.).

<Initial fillability>
After loading, an initial filling operation was performed, and then a nozzle check pattern was printed, and the initial filling performance was evaluated according to the following criteria.
〔Evaluation criteria〕
○: The initial filling operation performed until the nozzle omission disappeared could be filled once.
(Triangle | delta): The initial filling operation performed until nozzle omission disappeared was required twice or more.
×: No nozzle omission occurred even after the initial filling operation was performed four times or more.

<Recovery>
A solid image was printed for each color, and when nozzle omission occurred, recovery operation was performed, and printing was performed on 10 A4 size recording media (Xerox 4024 paper, manufactured by Fuji Xerox Office Supply Co., Ltd.) for each color. The mass of the cartridge before and after printing was measured, and the amount of ink used (g) was calculated. Further, the number of recovery operations performed during printing was measured.

<Preservability>
If each ink cartridge is set in the printer and left for 7 days at 60 ° C., then it can be restored by one cleaning operation of a conventionally known ink jet printer, and if it can be restored by 2 to 5 times, Δ If it did not return even after 5 times, it was marked as x.

  Scratchability, image sharpness, and show-through were tested by degassing each ink and filling the cartridge, and loading it into an ink jet printer EM-900 (manufactured by Seiko Epson Corporation). Printing was performed by changing the driving voltage, frequency, and pulse width of the head. The printing conditions were Mj 35 pl, Vj 20 m / sec, frequency 1 kHz, recording density 360 dpi, and one-pass printing. As the print pattern, a general document image including a solid at 100% duty, a character, and a two-color overlapping portion boundary of each ink was printed.

<Abrasion>
Three types of recording media (Xerox 4024 paper / Fuji Xerox Office Supply Co., Ltd.), PM photographic paper <Glossy>; KA450PSK / Seiko Epson Corporation, Super Fine Paper; KA4250NSF / Seiko Epson Corporation) An image formed with ink was printed. After 30 seconds, the sample was rubbed with a finger, cloth, eraser, and marking pen, and the state after the rub was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
A: No change in image due to rubbing on all three types of recording media.
○: No change in image due to rubbing between two types of recording media.
X: Image change due to rubbing occurred in two or more types of recording media.

<Image clarity>
After printing on each of the following recording media (1) to (3), the blur of the two-color overlap portion, the image blur, the color tone, and the image density are visually observed and a reflection type color spectrophotometric densitometer (manufactured by X-Rite) Was comprehensively examined and judged according to the following evaluation criteria.
〔recoding media〕
(1) My paper (NBS Ricoh Co., Ltd.)
(2) Paper source S and recycled paper (manufactured by NBS Ricoh Co., Ltd.)
(3) Xerox 4024 paper (Fuji Xerox Office Supply Co., Ltd.)
[Criteria]
A: All papers are clearly printed.
○: Some paper (recycled paper) has bleeding.
Δ: Bleeding occurs on all papers.
X: The blur has occurred so that the outline of the character and the boundary between the two color overlapping portions are not clear.

<Back-through>
A solid image on a recording medium (Xerox 4024 paper, manufactured by Fuji Xerox Office Supply Co., Ltd.) so that the density of each ink color measured with a reflective color spectrophotometric densitometer (manufactured by X-Rite) is 1.0. Formed. This image was visually observed from the back and evaluated according to the following criteria.
〔Evaluation criteria〕
A: When visually observed from the back side, the boundary between the solid image and the white background portion is completely unclear (the solid image cannot be recognized from the back side), and is a level that does not hinder the use of the double-sided printing.
◯: When visually observed from the back side, the boundary between the solid image and the white background is almost unclear (almost no solid image can be recognized from the back side), and it is a level that does not hinder even if it is used for double-sided printing.
Δ: When visually observed from the back side, the colorant of the solid image does not come off to the back side, but the boundary between the solid image and the white background is slightly unclear (a solid image can be recognized from the back side), and both sides Even if it is used for printing, it is at a level that does not hinder it.
X: When visually observed from the back side, the colorant of the solid image has fallen to the back side (a solid image can be recognized even from the back side) and is a level that cannot be used for double-sided printing.

FIG. 1 is an external perspective view showing an example of an ink cartridge before being loaded into the recording apparatus of the present invention. FIG. 2 is a front sectional view of the ink cartridge of FIG. FIG. 3 is a schematic front view showing an example of a serial type ink jet recording apparatus equipped with an ink cartridge containing the water-based ink of the present invention. FIG. 4 is an external perspective view showing an example of a recording unit integrated with the recording head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Side plate 2 Side plate 3 Main support guide rod 4 Sub support guide rod 5 Carriage unit 6 Head 6a Discharge surface (nozzle surface)
7 Ink Cartridge 7y Ink Cartridge 7m Ink Cartridge 7c Ink Cartridge 7k Ink Cartridge 8 Main Scanning Motor 9 Drive Pulley (Drive Timing Pulley)
10 Driven pulley (idler pulley)
DESCRIPTION OF SYMBOLS 11 Timing belt 12 Bottom plate 13 Sub frame 14 Sub frame 15 Conveyance roller 16 Paper 17 Sub scanning motor 18 Gear 19 Gear 21 Sub system 22 Cap means 23 Holder 24 Link member 25 Engagement part 26 Suction tube 27 Suction pump 28 Wiper blade 29 Blade Arm 30 Recording unit 31 Electrode 32 Nozzle 33 Ink tank 34 Lid member 41 Cartridge body 42 Ink absorber 43 Case 44 Upper lid member 45 Ink supply port 46 Seal ring 47 Air release port 50 Cap member 55 Seal member A Space

Claims (18)

  A water-based ink, wherein the colorant is a pigment, and the pigment has at least one hydrophilic group on the surface of the pigment and exhibits water dispersibility in the absence of a dispersant and a guanidine derivative.   The aqueous ink according to claim 1, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of guanidine.   The aqueous ink according to claim 1, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of aminoguanidine.   The aqueous ink according to claim 1, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of diphenylguanidine or triphenylguanidine.   The aqueous ink according to claim 1, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of a bisguanidine compound.   The aqueous ink according to claim 1, wherein the guanidine derivative is an inorganic acid salt or an organic acid salt of polyalkylene guanidine.   The water-based ink according to claim 1, wherein the content of the guanidine derivative is 0.1 to 1000 ppm.   The water-based ink according to claim 7, wherein the content of the guanidine derivative is 1 to 100 ppm.   The water-based ink according to claim 1, comprising a water-soluble organic solvent.   The water-based ink according to claim 9, wherein the water-soluble organic solvent is at least one selected from glycerin, diethylene glycol, 1,3-butanediol, triethylene glycol, and 2-pyrrolidone.   The aqueous ink according to claim 1, wherein the hydrophilic group on the surface of the pigment is at least one selected from a carboxyl group, a sulfone group, a carbonyl group, and a hydroxyl group.   The water-based ink according to claim 1, wherein the pigment has an average particle diameter of 10 to 200 nm.   The water-based ink according to any one of claims 1 to 12, wherein the water-based ink is at least one selected from cyan ink, magenta ink, yellow ink, and black ink.   14. An ink jet recording method using a plurality of inks selected from cyan ink, magenta ink, yellow ink and black ink in combination, wherein the ink according to claim 13 is used as at least one of them. Recording method.   An ink jet recording method comprising at least an ink flying step of forming an image by applying a stimulus to the water-based ink and causing the water-based ink to fly, wherein the water-based ink according to any one of claims 1 to 13 is used as the water-based ink. An ink jet recording method comprising using the ink jet recording method.   An ink cartridge comprising the water-based ink according to claim 1 contained in a container.   An ink jet recording apparatus comprising at least an ink flying unit that applies an stimulus to the water-based ink according to any one of claims 1 to 13 and causes the water-based ink to fly to form an image. An ink jet recording apparatus loaded with the water-based ink according to any one of 1 to 13. An ink recorded matter comprising an image formed using the water-based ink according to any one of claims 1 to 13 on a recording medium.

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