JP2014172963A - Ink for inkjet recording, ink cartridge, inkjet recording method, inkjet recording device and ink printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink for inkjet recording which has good storage stability of ink, can obtain a high image density and has good discharge stability of ink, an ink cartridge using the ink, an inkjet recording method, an inkjet recording device and an ink recorded matter.SOLUTION: There is provided ink for inkjet recording which comprises at least water, a humactant and a coloring agent, wherein the humectant contains at least one of isopropylidene glycerol and 3-ethyl-3-hydroxymethyloxetane and the coloring agent is carbon black obtained by subjecting carbon black having a BET specific surface area of 90 to 150 m/g to ozone oxidation to have a volatile content of 10 to 20%.

Description

  The present invention relates to an ink for ink jet recording, and particularly relates to the ink for ink jet recording, an ink cartridge containing the ink, an ink jet recording method using the ink, a recording apparatus, and an ink recorded matter.

In recent years, as an image forming method, since the process is simple and full color can be easily obtained as compared with other recording methods, there is an advantage that a high-resolution image can be obtained even with an apparatus having a simple configuration. The method has become widespread.
Inkjet recording is a method in which a small amount of ink is ejected with bubbles generated by heat, pressure generated by using piezoelectricity or static electricity, and the ink is attached to a recording medium such as paper and dried quickly (or recording). This is a method of forming an image (by penetrating into a medium). The inkjet recording method has been expanded to use for personal and industrial printers and printing.

In the ink jet recording apparatus, a water-based ink using a water-soluble dye as a colorant is mainly used. However, the dye ink has a defect that it is inferior in weather resistance and water resistance. Therefore, in recent years, research on pigment inks using pigments instead of water-soluble dyes has been advanced.
However, the pigment ink is still inferior in color development, ink ejection stability, and storage stability as compared with dye ink. In addition, with the improvement of image quality improvement technology for OA printers, image density equivalent to that of dye ink is required for both pigment ink and plain paper as a recording medium. However, when plain paper is used as a recording medium, the pigment ink has a problem that the pigment concentration on the paper surface is lowered by penetrating into the paper and the image density is lowered.

  In recent years, demand for industrial applications has been increasing, and high-speed printing is desired. Ink jet printers equipped with line heads have been proposed along with high-speed printing. In order to increase the drying speed of the ink adhering to the recording medium for high-speed printing, means for increasing the drying speed by adding a penetrant to the ink and allowing water to penetrate into the recording medium is taken. However, with such means, not only water but also the permeability of the pigment into the recording medium is increased, and the image density is further reduced.

As means for improving the ink ejection stability and storage stability and improving the image density, Patent Document 1 discloses that the wetting agent contains at least one of isopropylideneglycerol and 3-ethyl-3-hydroxymethyloxetane, Ink jet recording inks containing a self-dispersible pigment exhibiting water dispersibility in the absence of a dispersant as a colorant have been proposed.
Self-dispersing pigments can be obtained by a wet oxidation method. Carbon black is oxidized with hypochlorous acid (Patent Document 2), and the ratio of the surface functional group amount / specific surface area ratio of carbon black is controlled. There is a method of performing wet oxidation using a sulfate (Patent Document 3).

However, in the ink described in Patent Document 2, since water is used as a solvent in the treatment of carbon black with hypochlorite, dehydration and washing are necessary, and salt and the like remain in the washing. When ink containing carbon black oxidized with hypochlorous acid is used for inkjet recording, the ink storage stability is not fully satisfactory, and in the case of plain paper, the image density is also satisfactory. It wasn't possible.
In addition, in the ink described in Patent Document 3, the amount of surface functional groups and specific surface area of carbon black are defined for the purpose of improving dispersion stability, but wet oxidation using peroxodisulfate or the like. For the same reason as in the case of the ink described in Patent Document 2, storage stability and image density are not satisfactory.

Patent Document 4 proposes the use of carbon black in which the volatile content of carbon black oxidized with ozone is 25% or more, preferably 30%. However, if the volatile content is high, the water dispersibility is improved, but the stability decreases due to the increase of impurities during oxidation, the water compatibility becomes too high, and the penetration of the pigment into the paper with water occurs. It becomes easy and sufficient image density cannot be obtained.
Furthermore, Patent Document 5 proposes the use of carbon black having an oil absorption of 800 to 1000 g / 100 g based on DIN ISO 787/5 and a BET specific surface area of 250 to 500 m ² / g. However, if the BET specific surface area is high, the dispersion becomes insufficient and sufficient image density cannot be obtained.

  The present invention has been made in view of the present situation, and an object of the present invention is to provide an ink for ink jet recording that has good ink storage stability, high image density, and good ink ejection stability. And

In order to solve the above problems, the invention according to claim 1 is an inkjet recording ink comprising at least water, a wetting agent, and a colorant, wherein the wetting agent is isopropylideneglycerol represented by the following (formula 1): And at least one of 3-ethyl-3-hydroxymethyloxetane represented by the following (formula 2), and the colorant ozone-oxidizes carbon black having a BET specific surface area of 90 to 150 m ² / g to reduce the volatile content. An ink for ink-jet recording, characterized in that the carbon black is 10 to 20% by mass.

  According to the above ink for ink jet recording, the above problems can be solved and the object can be achieved. That is, the present invention can provide an ink for ink jet recording having good ink storage stability, high image density, and good ink ejection stability.

It is explanatory drawing which shows an example of the ink cartridge of this invention. It is explanatory drawing including the case (exterior) of the ink cartridge (FIG. 1) of this invention. 1 is a schematic diagram illustrating an example of a serial type inkjet recording apparatus of the present invention. FIG. 4 is a partially enlarged explanatory view of the ink jet recording apparatus shown in FIG. 3. FIG. 4 is another partially enlarged explanatory view of the ink jet recording apparatus shown in FIG. 3.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

<Ink for inkjet recording>
The ink for inkjet recording of the present invention (hereinafter sometimes referred to as “ink”) contains at least water, a wetting agent, and a colorant, and further contains other components as necessary. Specifically, the wetting agent contains at least one of isopropylideneglycerol represented by the following (formula 1) and 3-ethyl-3-hydroxymethyloxetane represented by the following (formula 2), and the colorant Is a carbon black having a BET specific surface area of 90 to 150 m ² / g and ozone-oxidized carbon black having a volatile content of 10 to 20% by mass.

〔water〕
As water used in the present invention, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. The blending amount of water is preferably 20 to 60% by mass, and more preferably 20 to 50% by mass with respect to the total amount of ink.

[Wetting agent]
The ink of the present invention contains at least one of isopropylideneglycerol represented by the above formula 1 and 3-ethyl-3-hydroxymethyloxetane represented by the above formula 2 as a wetting agent. When isopropylideneglycerol and 3-ethyl-3-hydroxymethyloxetane are used in combination, their mixing ratio can be arbitrarily adopted.
The reason for the effect of containing the wetting agent is not necessarily clarified, but it is difficult to penetrate into the paper together with the color material (coloring agent), and the color material stays on the paper surface and a high image density is obtained. Conceivable.

The wetting agent of the present invention is preferably any one selected from the following (1), (2), (3), and (4).
(1) Wetting agent comprising a combination of isopropylideneglycerol and glycerin (2) Wetting agent comprising 3-ethyl-3-hydroxymethyloxetane and glycerin (3) Wetting comprising a combination of the following (i) and (ii) Agent (i) Isopropylideneglycerol and glycerin (ii) At least one selected from 3-ethyl-3-hydroxymethyloxetane, 1,3-butanediol, 3-methyl-1,3-butanediol and 2-pyrrolidone (4) Wetting agent comprising a combination of (iii) and (iv): (iii) 3-ethyl-3-hydroxymethyloxetane and glycerin (iv) 1,3-butanediol, 3-methyl-1,3- At least one selected from butanediol and 2-pyrrolidone

In contrast to the humectant of (1) and (2), the humectant of (3) and (4) is a humectant other than isopropylideneglycerol or 3-ethyl-3-hydroxymethyloxetane and glycerin. By combining the agents, there is an advantage that the characteristics of each wetting agent can be utilized, and the viscosity can be easily adjusted.
Among these, a combination of isopropylideneglycerol and glycerol, a combination of 3-ethyl-3-hydroxymethyloxetane and glycerol, a combination of isopropylideneglycerol, glycerol and 2-pyrrolidone, 3-ethyl-3-hydroxy A combination of methyl oxetane, glycerin, and 2-pyrrolidone is particularly preferable.

In addition to the above-mentioned wetting agent, a predetermined wetting agent can be used in combination with the ink for inkjet recording of the present invention as necessary.
Examples of the predetermined wetting agent include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, and carbonic acid. Ethylene, other wetting agents, and the like.

(Polyhydric alcohols)
Examples of the polyhydric alcohols include diethylene glycol, dipropylene glycol, triethylene glycol, 1,5-pentanediol, propylene glycol, 2-methyl-2,4-pentanediol, ethylene glycol, tripropylene glycol, and tetraethylene. Glycol, hexylene glycol, polyethylene glycol, polypropylene glycol, 1,6-hexanediol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol , Trimethylolethane, trimethylolpropane, and the like.

(Polyhydric alcohol alkyl ethers)
Examples of the polyhydric alcohol alkyl ethers include 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, and the like. Can be mentioned.

(Polyhydric alcohol aryl ethers)
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

(Nitrogen-containing heterocyclic compounds)
Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone, and the like. .

(Amides)
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, and the like.

(Amines)
Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine, and the like.

(Sulfur-containing compounds)
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.

(Other wetting agents)
The other wetting agent preferably contains a saccharide. Examples of the saccharide include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides, and the like. Specific examples include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, and the like.
Here, the polysaccharide means a saccharide in a broad sense, and is used to include a substance that exists widely in nature such as α-cyclodextrin and cellulose.
Derivatives of these saccharides include reducing sugars (for example, sugar alcohols (general _{formula: HOCH 2 (CHOH) nCH 2} OH ( where, n is represented by an integer of 2-5). ), Oxidized sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids, etc. Among these, sugar alcohols are preferable, and specific examples include maltitol, sorbit, and the like.

The content of the wetting agent in the ink is preferably 20 to 50% by mass, and more preferably 20 to 40% by mass. When the content is less than 20% by mass, the ink ejection stability may be deteriorated, and when it exceeds 50% by mass, the drying property on paper is inferior and the character quality on plain paper may be deteriorated. .
However, the amount of isopropylideneglycerol represented by (Formula 1) and / or 3-ethyl-3-hydroxymethyloxetane represented by (Formula 2) in the wetting agent is 10 to 40% by mass, preferably 15-30 mass% is suitable.

  The mass ratio of the pigment and the wetting agent has a great influence on the ink ejection stability from the head. If the blending amount of the wetting agent is small even though the pigment solid content is high, water evaporation near the ink meniscus of the nozzle may progress and cause ejection failure. Therefore, in the ink of the present invention, a blending ratio of 5 to 60 parts by weight of pigment, preferably 10 to 40 parts by weight of pigment is appropriate for 100 parts by weight of the wetting agent.

[Colorant]
In the ink of the present invention, carbon black having a BET specific surface area of 90 to 150 m ² / g, preferably 80 to 130 m ² / g is oxidized by ozone treatment to have a volatile content of 10 to 20% by mass, preferably 12 to 18%. Carbon black adjusted to mass% (hereinafter, carbon black oxidized by ozone treatment may be referred to as “ozone oxidized carbon black”) is used.

When the BET specific surface area of the raw material carbon black is less than 90 m ² / g, the image density becomes low. On the other hand, when the BET specific surface area exceeds 150 m ² / g, the carbon black particle diameter and / or viscosity change during high-temperature storage in the ozone-oxidized carbon black dispersion and the inkjet recording ink using the ozone-oxidized carbon black dispersion growing.
In addition, the BET specific surface area in this invention is a value by the measuring method of DIN 66132 description.

Further, by setting the volatile content of ozone-oxidized carbon black to 10% by mass or more, a print density equal to or higher than that obtained when dye ink is used can be obtained. However, if the volatile content exceeds 20% by mass, the printing defect occurrence rate tends to be high when ejected by the ink jet recording apparatus.
In addition, the volatile matter in this invention is a value by the measuring method of DIN 53 552.

  The ozone treatment method is not particularly limited, but a dry method in which ozone gas is circulated through carbon black is preferable because of its high oxidation treatment ability. In the treatment using water, a reaction between water and ozone occurs, so that sufficient oxidation may not be possible. Ozone is obtained by passing air or oxygen through an ozone generator.

The adjustment of the volatile matter can be controlled by adjusting the amount of ozone and the treatment time. If the amount of ozone is increased or the treatment time is lengthened, carbon black having a large amount of volatile matter can be obtained. The treatment time and the volatile content are in a substantially proportional relationship. However, since the volatile content reaches saturation when a certain time is exceeded, it is necessary to make adjustment while confirming the volatile content. Further, the above conditions may be appropriately adjusted depending on the characteristics of carbon black before oxidation treatment, impurities, and the like.
Specifically, the ozone concentration is ^{3 to} 20 g / m ³ , the treatment time is 0.5 to 20 hours, the pressure may be increased or decreased, but it is performed at normal pressure from an economic and safety point of view. Is preferred. Regardless of whether the type of reaction vessel is a fixed bed or a fluidized bed, the temperature is controlled so that no dust explosion occurs.

The raw material carbon black may have a BET specific surface area of 90 to 150 m ² / g, preferably 100 to 130 m ² / g, but the oil absorption (DIN ISO 787/5 method) is 230 g / 100 g in terms of image density. As described above, preferably 100 to 800 g / 100 g is preferable. Various carbon blacks such as furnace black, lamp black, acetylene black, and gas black can be used, but gas black is preferable in terms of image density. Moreover, the thing with an average primary particle diameter of 13-30 nm is preferable. The average primary particle diameter of carbon black can be calculated from the particle diameter and number of the photographed image obtained by photographing particles using an electron micrograph.

In addition to the ozone-oxidized carbon black, the colorant of the present invention can be used in combination with an oxidized or alkali-treated surface, a resin-coated surface, or a grafted or encapsulated carbon black. However, in order to cover the surface with a dispersant, those not subjected to a treatment such as resin coating are preferred. The carbon black used in combination has an average primary particle size of 10 to 50 nm, a BET specific surface area of 50 to 400 m ² / g, a DBP absorption of 40 to 500 mL / 100 g, a volatile content of 0.5 to 20% by mass, and a pH of 2 to 2. 9 is preferred.
However, the amount of the ozone-oxidized carbon black in the colorant in the ink of the present invention is 50 to 100% by mass, preferably 60 to 100% by mass.

  The content of the colorant in the ink is preferably 1 to 20% by mass, and more preferably 2 to 16% by mass. If the content is less than 2% by mass, the print density may be insufficient and the ink ejection stability may be lowered. On the other hand, even if it exceeds 16% by weight, the print density may not be significantly improved, and the dryness on the paper surface may be inferior, and the character quality on plain paper may be lowered. For this reason, the content of the colorant in the ink is preferably within the above range.

The reason why the ink containing the ozone-oxidized carbon black of the present invention can achieve both image density and storage stability is not necessarily clarified, but is presumed as follows.
That is, as a result of the inventors' investigation on the volatile content of wet-oxidized carbon black, when the volatile content increases, the carbon black tends to stay on the paper surface and the image density increases. The image density was improved when the volatile content exceeded about 20% by mass, but it was found that when the volatile content was further increased, saturation tendency occurred and sufficient image density could not be obtained. Also, as the volatile content increases, the hydrophilicity of carbon black increases and the dispersibility improves, but it is also found that the stability of the ink deteriorates due to the increase in impurities due to oxidation, and the image density and the storage stability of the ink are reduced. Although it was impossible to achieve both, the specific surface area and the ratio of volatile matter were examined, but they were not compatible.
Therefore, the present inventors have further studied, and by performing the oxidation method by ozone treatment, even when the volatile content is 10 to 20% by mass, the BET specific surface area is set to 90 to 150 m ² / g. The result was able to satisfy both the concentration and storage stability. It has also been found that the image density can be improved by adjusting the pH of the pigment dispersion in which the pigment is dispersed in water to 6-8. A metal hydroxide is preferably used for pH adjustment, and examples thereof include lithium hydroxide, sodium hydroxide, and potassium hydroxide.

To actually prepare the ink of the present invention, ozone-oxidized carbon black is dispersed in water and the pH is adjusted to obtain a pigment dispersion, and this pigment dispersion (carbon black dispersion) is mixed with a wetting agent, water, and the like. Done. In this case, the pigment concentration in the pigment dispersion is preferably 0.1 to 50% by mass, particularly preferably 0.1 to 30% by mass.
Further, when an ether type polyurethane resin having an acid value of 40 to 100 mg KOH / g is contained in the pigment dispersion, the storage stability can be improved while maintaining the image density. The acid value is a value measured by a method according to JIS K0070.

[Dispersant]
Moreover, you may use a dispersing agent for the pigment dispersion in the range which does not impair the effect of this invention. Examples of the dispersant include various surfactants such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant, and a polymer type dispersant. These may be used alone or in combination of two or more.

(Anionic surfactant)
Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, polyoxyalkyl ether sulfates. Salt, polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, naphthalenesulfonate formalin condensate, alkyl type phosphate ester, alkylallylsulfone hydrochloride, diethyl Examples include sulfosuccinate, diethylhexyl sulfosuccinate, and dioctyl sulfosuccinate.

(Cationic surfactant)
Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

(Amphoteric surfactant)
Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline. Derivatives and the like.

(Nonionic surfactant)
Examples of nonionic surfactants include the following.
Ether-based interfaces such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyallylalkyl alkyl ether Active agent;
Polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate Ester surfactants such as
2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol Acetylene glycol surfactants such as

[Other ingredients]
Other components are not particularly limited and may be appropriately selected as necessary. For example, penetrants, pH adjusters, water-dispersible resins, antiseptic / antifungal agents, chelating reagents, rust inhibitors, and antioxidants Well-known various additives, such as an agent, a ultraviolet absorber, an oxygen absorber, a light stabilizer, are mentioned.

(Penetration agent)
The penetrant preferably contains either a polyol compound having 8 to 11 carbon atoms or a glycol ether compound having 8 to 11 carbon atoms.
The penetrant is different from the wetting agent and has a relatively low wettability compared to the wetting agent. Therefore, the penetrating agent can be referred to as a non-wetting agent. It is a meaning. These preferably have a solubility of between 0.2% and 5.0% by weight in 25 ° C. water.
Among these, 2-ethyl-1,3-hexanediol [solubility: 4.2% (25 ° C.)], 2,2,4-trimethyl-1,3-pentanediol [solubility: 2.0% (25 ° C)] is particularly preferred.

  As other polyol compounds, examples of the aliphatic diol include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3- Propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1, 2-diol etc. are mentioned.

  Other penetrants that can be used in combination are not particularly limited as long as they can be dissolved in the ink and adjusted to the desired physical properties, and can be appropriately selected according to the purpose. For example, diethylene glycol monophenyl ether, ethylene Glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, alkyl and aryl ethers of polyhydric alcohols such as tetraethylene glycol chlorophenyl ether, lower alcohols such as ethanol, etc. Is mentioned.

  The content of the penetrant in the ink is preferably 0.1 to 4.0% by mass. If the content is less than 0.1% by mass, quick drying may not be obtained and a blurred image may be obtained. On the other hand, when the content exceeds 4.0% by mass, the dispersion stability of the colorant is impaired, the nozzle is easily clogged, and the permeability to the recording medium is unnecessarily high. There may be a decrease in the image density or a show-through.

(PH adjuster)
The pH adjuster is not particularly limited as long as it can adjust the pH to 8.5 to 11 and preferably 9 to 11 without adversely affecting the ink to be prepared, and is appropriately selected according to the purpose. Examples thereof include alcohol amines, alkali metal hydroxides, ammonium hydroxides, phosphonium hydroxides, alkali metal carbonates, and the like.

When the pH is less than 8.5 or more than 11, the amount of the ink-jet head or ink supply unit that melts out is large, and problems such as ink deterioration, leakage, and ejection failure may occur. When it is less than 8.5, the ink pH may decrease during storage of the ink, and the polymer fine particles may aggregate due to an increase in the particle diameter.
The pH can be measured by, for example, a pH meter HM-30R (manufactured by TOA-DKK).

(Alcohol amines)
Examples of the alcohol amines include diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, and the like.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.

(Ammonium hydroxide)
Examples of the ammonium hydroxide include ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, and the like.

  Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, and potassium carbonate.

(Water dispersible resin)
The water-dispersible resin has excellent film-forming properties (image formability), high water repellency, high water resistance, and high weather resistance, and has high water resistance and high image density (high color development). Useful for. Specific examples of the water-dispersible resin include condensation-type synthetic resins, addition-type synthetic resins, natural polymer compounds, and the like.

Examples of the condensed synthetic resin include polyester resin, polyurethane resin, polyepoxy resin, polyamide resin, polyether resin, poly (meth) acrylic resin, acrylic-silicone resin, and fluorine-based resin.
Examples of the addition type synthetic resin include polyolefin resins, polystyrene resins, polyvinyl alcohol resins, polyvinyl ester resins, polyacrylic acid resins, unsaturated carboxylic acid resins, and the like.
Examples of the natural polymer compound include celluloses, rosins, and natural rubber.
Among these, polyurethane resin fine particles, acrylic-silicone resin fine particles, and fluorine-based resin fine particles are particularly preferable.

The average particle size (D50) of the water-dispersible resin is related to the viscosity of the dispersion, and for the same composition, the viscosity at the same solid content increases as the particle size decreases.
The average particle diameter (D50) of the water-dispersible resin is preferably 50 nm or more so that the ink does not have an excessively high viscosity. Further, when the particle size is several tens of μm, it becomes larger than the nozzle opening of the ink jet head and cannot be used. If particles having a large particle diameter are present in the ink even if smaller than the nozzle opening, the ejection stability is deteriorated. Therefore, the average particle diameter (D50) is more preferably 200 nm or less in order not to disturb the ink ejection stability.

  The average particle diameter (D50) can be measured by a conventional method, for example, using a particle size analyzer UPA150 manufactured by Nikkiso Co., Ltd. In addition, the average particle diameter (D50) can be controlled by the peripheral speed of the rotating part of the disperser, the dispersion time, the dispersion flow rate, and the dispersion temperature when the water dispersible resin is dispersed using the disperser. .

  The water-dispersible resin has a function of fixing the water-dispersed colorant on the paper surface, and is preferably formed into a film at room temperature to improve the fixability of the color material. Therefore, it is preferable that the minimum film-forming temperature (MFT) of the water-dispersible resin is 30 ° C. or less. Further, when the glass transition temperature of the water-dispersible resin is -40 ° C. or lower, the resin film becomes more viscous and the printed matter is tacky. Therefore, the water-dispersible resin has a glass transition temperature of −30 ° C. or higher. It is preferable.

  The content of the water-dispersible resin in the inkjet ink is preferably 1 to 15% by mass, more preferably 2 to 7% by mass in terms of solid content.

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

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

(Rust inhibitor)
Examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and the like.

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

(UV absorber)
Examples of the ultraviolet absorbers include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, salicylate ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, nickel complex ultraviolet absorbers, and the like.

<Inkjet ink manufacturing method>
The ink-jet ink of this embodiment is produced by dispersing or dissolving at least a water-dispersible colorant, a wetting agent and water, and other components in an aqueous medium as required, and further stirring and mixing as necessary. .
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.
The physical properties of the ink for ink jet recording of the present invention are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension and the like are preferably in the following ranges.

The viscosity of the ink for inkjet recording at 25 ° C. is preferably 3 to 20 mPa · s, and more preferably 3 to 15 mPa · s. By setting the ink viscosity to 3 mPa · s or more, the effect of improving the printing density and the character quality can be obtained. On the other hand, by suppressing the ink viscosity to 20 mPa · s or less, it is possible to ensure the discharge performance. The ink viscosity is preferably adjusted with a surfactant or a solvent.
The viscosity can be measured at 25 ° C. using, for example, a viscometer (RL-550, manufactured by Toki Sangyo Co., Ltd.).

  Further, the surface tension of the ink for ink jet recording is preferably 40 mN / m or less, more preferably 10 to 35 mN / m at 25 ° C. When the surface tension of the ink is 10 to 30 mN / m, the penetrability of the ink is enhanced and the drying property is good even when recording on plain paper, and the bleed is reduced. If the surface tension exceeds 40 mN / m, leveling of the ink on the recording medium (evenly wetting and spreading the ink on the surface of the recording medium) hardly occurs and the drying time may be prolonged. The surface tension of the ink is preferably adjusted with a surfactant.

<Ink cartridge>
The ink cartridge of the present invention accommodates the ink for ink jet recording of the present invention in a container, and can also constitute other members appropriately selected as necessary.
The shape, structure, size, and material of the container are not particularly limited and can be appropriately selected according to the purpose. Preferred examples include those having at least an ink bag formed of an aluminum laminate film, a resin film, or the like.

One embodiment of the ink cartridge of the present invention will be described with reference to FIGS.
FIG. 1 is a view showing an example of the ink cartridge of the present invention, and FIG. 2 is a view including a case (exterior) of the ink cartridge 200 of FIG.
As shown in FIG. 1, the ink cartridge 200 is filled into the ink bag 241 from the ink inlet 242 and 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. 2, the ink bag 241 is usually housed in a plastic cartridge case 244 and is detachably mounted on various ink jet recording apparatuses.

<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.

The ink flying step is a step of forming an image by applying a stimulus to the ink jet ink of the present invention and causing the ink jet ink to fly.
The ink flying means is means for forming an image by applying a stimulus to the ink-jet ink of the present invention and causing the ink-jet 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 superheater, a pressurizer, a piezoelectric element, a vibration generator, an ultrasonic oscillator, and a light.
Specifically, a piezoelectric actuator such as a piezoelectric element such as a piezoelectric element, a thermal actuator that uses a phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a shape that uses a metal phase change due to a temperature change Memory alloy actuators, electrostatic actuators using electrostatic force, and the like can be mentioned.

  There is no restriction | limiting in particular as an aspect of the said ink flying, It changes according to the kind etc. of the said stimulus. For example, when the stimulus is “heat” as a flight mode, thermal energy corresponding to a recording signal is applied to the ink in the recording head using, for example, a thermal head, and bubbles are formed in the ink by the thermal energy. And a method in which the ink is ejected and ejected as droplets from the nozzle holes of the recording head by the pressure of the bubbles.

  Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And a method of ejecting and ejecting the ink as droplets from the nozzle holes of the recording head.

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, one aspect of carrying out the ink jet recording method of the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings.
FIG. 3 is a schematic view showing an example of the serial type ink jet recording apparatus of the present invention. The ink jet recording apparatus shown in FIG. 3 stocks an apparatus main body 101, a paper feed tray 102 for loading paper mounted on the apparatus main body 101, and paper on which an image is recorded (formed) mounted on the apparatus main body 101. A paper discharge tray 103 and an ink cartridge loading unit 104.

  On the upper surface of the ink cartridge loading unit 104, an operation unit 105 such as operation keys and a display is arranged. The ink cartridge loading unit 104 has a front cover 115 that can be opened and closed for attaching and detaching the ink cartridge 200.

In the apparatus main body 101, as shown in FIGS. 4 and 5, the carriage 133 is slid in the main scanning direction by guide rods 131 and stays 132 which are horizontally mounted on left and right side plates (not shown). The main scanning motor moves and scans in the direction indicated by the arrow in FIG.
The carriage 133 is provided with a recording head 134 composed of four ink jet recording heads that eject 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 the ink jet recording head constituting the recording head 134, a piezoelectric actuator such as a piezoelectric element, a thermal actuator using phase change due to liquid film boiling using an electrothermal transducer such as a heating resistor, a metal phase due to temperature change, etc. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like provided as energy generating means for discharging ink can be used.

In addition, 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 the ink from the ink cartridge 200 of the present invention loaded in the ink cartridge loading unit 104 via an ink supply tube (not shown) and is replenished.

  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, a half-moon roller (feeding) that separates and feeds the paper 142 one by one from the paper stacking unit 141 The paper roller 143) and the paper supply roller 143 are opposed to each other, and a separation pad 144 made of a material having a large friction coefficient is provided. The separation pad 144 is urged toward the paper feed roller 143 side.

  As a transport unit for transporting the paper 142 fed from the paper feed unit below the recording head 134, a transport belt 151 for transporting the paper 142 by electrostatic adsorption and a guide 145 from the paper feed unit. The counter roller 152 for transporting the paper 142 fed via the transport belt 151 with the transport belt 151 and the paper 142 fed substantially vertically upward are changed by approximately 90 ° so as to follow the transport belt 151. For this purpose, a conveyance guide 153 and a tip pressure roller 155 urged toward the conveyance belt 151 by a pressing member 154 are provided.

In addition, a charging roller 156 that is a charging unit for charging the surface of the conveyance belt 151 is provided.
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 that is not subjected to resistance control, for example, a copolymer of tetrafluoroethylene and ethylene (ETFE), and the surface layer. It has a back layer (medium resistance layer, earth layer) that is made of the same material and has resistance controlled by carbon.
On the back side of the conveyance belt 151, a guide member 161 is arranged corresponding to a printing area by the recording head 134.

  Note that, 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 conveyance belt 151, a paper discharge roller 172, and a paper discharge roller 173 are provided. The paper discharge tray 103 is disposed below the paper discharge roller 172.

A double-sided paper feeding unit 181 is detachably mounted on 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 it again between the counter roller 152 and the transport belt 151.
A manual paper feed unit 182 is provided on the upper surface of the duplex paper feed unit 181.

In this ink jet recording apparatus, the paper 142 is separated and fed one by one from the paper feed unit, and the paper 142 fed substantially vertically upward is guided by the guide 145 and between the transport belt 151 and the counter roller 152. It is sandwiched and conveyed. 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 approximately 90 °.
At this time, the conveying belt 151 is charged by the charging roller 156, and the sheet 142 is electrostatically attracted to the conveying 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 paper 142 to record one line, and after the paper 142 is conveyed by a predetermined amount, Record the next line.
Upon receiving a recording end signal or a signal that the trailing edge of the sheet 142 has reached the recording area, the recording operation is terminated and the sheet 142 is discharged onto the discharge tray 103. When the ink remaining amount near end 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 of the present invention 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 installed vertically and has a front loading configuration.
Therefore, even when the upper portion of the apparatus main body 101 is closed and installed, for example, when stored in a rack or when an object is placed on the upper surface of the apparatus main body 101, the ink cartridge 200 is used. Can be easily exchanged.

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

<Ink record>
What was recorded by the ink jet recording method of the present invention is the ink recorded matter of the present invention. Specifically, the ink recorded matter of the present invention has an image formed on the recording medium using the ink in the ink media set of the present invention.

The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plain paper, coated paper for printing, glossy paper, special paper, cloth, film, and OHP sheet. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, at least one of plain paper and coated paper for printing is preferable.
The plain paper is advantageous in that it is inexpensive. The coated paper for printing is advantageous in that it provides a smooth glossy image at a relatively low cost as compared with glossy paper. So far, the coated paper for printing has poor drying properties and is generally difficult to use for ink jet printing. However, the ink of the present invention has improved drying properties and can be used.
The ink recorded matter has high image quality, no bleeding, excellent temporal stability, and can be suitably used for various purposes as a material on which various prints or images are recorded.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, carbon black dispersions were prepared and used. I made ink. In the examples, “part” and “%” are based on mass.

(Preparation Example 1) Carbon black dispersion A
Degussa carbon black (PRINTEX-U (oil absorption 460 g / 100 g))
200 g is put into a cylindrical ozone treatment device, ozone is generated by an ozone generator (Ktohira Industry Co., Ltd .: KQS-120), and ozone oxidation treatment is performed by maintaining the treatment temperature at about 30 ° C. in an ozone atmosphere. And ozone-oxidized carbon black a was obtained. The obtained ozone-oxidized carbon black a had a volatile content of 13% and a BET specific surface area of 110 m ² / g.
A 20% aqueous solution of NaOH was added to 20.0 parts of the above ozone-oxidized carbon black and 70.0 parts of distilled water, the pH was adjusted to 7.0, and distilled water was added so that the total amount was 100 parts.
Next, after pre-mixing the above-mentioned pH-adjusted materials, a peripheral speed of 10 m / s using a 0.3 mm zirconia bead and a liquid temperature of 10 ° C. using a disk type bead mill (manufactured by Shinmaru Enterprises: KDL type batch type). For 5 minutes. Coarse particles (particles having a particle size of 3000 nm or more) were separated using a centrifuge (manufactured by Kubota Corporation: Model-3600) to obtain a carbon black dispersion A.
The “oil absorption amount” is obtained by “DIN ISO 787/5 method” (the same applies hereinafter).

(Preparation Example 2) Carbon black dispersion B
Other than using Degussa carbon black (PRINTEX 140 (oil absorption 450 g / 100 g)) instead of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption 460 g / 100 g)), adjusting the ozone generation amount and the processing time. Produced ozone-oxidized carbon black b in the same manner as in Preparation Example 1. The obtained ozone-oxidized carbon black b had a volatile content of 10% and a BET specific surface area of 90 m ² / g.
Next, a carbon black dispersion B was obtained in the same manner as in Preparation Example 1 except that the ozone-oxidized carbon black b was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Preparation Example 3) Carbon black dispersion C
Other than using Degussa carbon black (PRINTEX 140 (oil absorption 450 g / 100 g)) instead of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption 460 g / 100 g)), adjusting the ozone generation amount and the processing time. Produced ozone-oxidized carbon black c in the same manner as in Preparation Example 1. The obtained ozone-oxidized carbon black c had a volatile content of 20% and a BET specific surface area of 90 m ² / g.
Next, a carbon black dispersion C was obtained in the same manner as in Preparation Example 1 except that the ozone-oxidized carbon black c was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Preparation Example 4) Carbon black dispersion D
Except that carbon black (NIPEX 160, oil absorption amount 620 g / 100 g) manufactured by Degussa was used in place of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption amount 460 g / 100 g)), and the ozone generation amount and treatment time were adjusted. In the same manner as in Preparation Example 1, ozone-oxidized carbon black d was obtained. The obtained ozone-oxidized carbon black d had a volatile content of 10% and a BET specific surface area of 150 m ² / g.
Next, a carbon black dispersion D was obtained in the same manner as in Preparation Example 1, except that the ozone-oxidized carbon black d was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Preparation Example 5) Carbon black dispersion E
A carbon black (NIPEX 160 (oil absorption amount 620 g / 100 g)) manufactured by Degussa Co. was used instead of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption amount 460 g / 100 g)), and the ozone generation amount and the treatment time were adjusted. Produced ozone-oxidized carbon black e in the same manner as in Preparation Example 1. The obtained ozone-oxidized carbon black e had a volatile content of 20% and a BET specific surface area of 150 m ² / g.
Next, a carbon black dispersion E was obtained in the same manner as in Preparation Example 1 except that the ozone-oxidized carbon black e was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Preparation Example 6) Carbon black dispersion F
A carbon black dispersion F was obtained in the same manner as in Preparation Example 1 except that the same ozone-oxidized carbon black as in Preparation Example 1 was used and the pH of the NaOH 20% aqueous solution was changed to pH 6.

(Preparation Example 7) Carbon black dispersion G
A carbon black dispersion G was obtained in the same manner as in Preparation Example 1 except that the same ozone-oxidized carbon black as in Preparation Example 1 was used and the pH of the NaOH 20% aqueous solution was changed to pH 8.

(Comparative Preparation Example 1) Carbon black dispersion H
A carbon black (PRINTEX 35 (oil absorption 42 g / 100 g) manufactured by Degussa) was used in place of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption 460 g / 100 g)), and the ozone generation amount and treatment time were adjusted. Produced ozone-oxidized carbon black h in the same manner as in Preparation Example 1. The obtained ozone-oxidized carbon black h had a volatile content of 13% and a BET specific surface area of 65 m ² / g.
Next, a carbon black dispersion H was obtained in the same manner as in Preparation Example 1 except that the ozone-oxidized carbon black h was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Comparative Preparation Example 2) Carbon black dispersion I
A carbon black (NIPEX 170 (oil absorption amount 760 g / 100 g)) manufactured by Degussa was used in place of the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption amount 460 g / 100 g)), and the ozone generation amount and treatment time were adjusted. Produced ozone-oxidized carbon black i in the same manner as in Preparation Example 1. The obtained ozone-oxidized carbon black i had a volatile content of 13% and a BET specific surface area of 200 m ² / g.
Next, a carbon black dispersion I was obtained in the same manner as in Preparation Example 1 except that the ozone-oxidized carbon black i was used in place of the ozone-oxidized carbon black a in Preparation Example 1.

(Comparative Preparation Example 3) Carbon black dispersion J
An ozone-oxidized carbon black j was obtained in the same manner as in Preparation Example 1 except that the carbon black (PRINTEX-U (oil absorption amount 460 g / 100 g)) of Preparation Example 1 was used and the ozone generation amount and treatment time were adjusted. The obtained ozone-oxidized carbon black j had a volatile content of 7% and a BET specific surface area of 110 m ² / g.
Next, a carbon black dispersion liquid J was obtained in the same manner as in Preparation Example 1, except that the ozone-oxidized carbon black j was used instead of the ozone-oxidized carbon black a in Preparation Example 1.

(Comparative Preparation Example 4) Carbon black dispersion K
An ozone-oxidized carbon black k was obtained in the same manner as in Preparation Example 1, except that the carbon black of Preparation Example 1 (PRINTEX-U (oil absorption amount 460 g / 100 g)) was used and the ozone generation amount and treatment time were adjusted. The obtained ozone-oxidized carbon black k had a volatile content of 28% and a BET specific surface area of 110 m ² / g.
Next, a carbon black dispersion liquid K was obtained in the same manner as in Preparation Example 1, except that the ozone-oxidized carbon black k was used in place of the ozone-oxidized carbon black a in Preparation Example 1.

(Comparative Preparation Example 5) Carbon black dispersion L
Carbon black (PRINTEX-U (oil absorption 460 g / 100 g)) manufactured by Degussa is mixed with 500 g of distilled water, and 1000 g of sodium hypochlorite aqueous solution (12%) is added dropwise with stirring and boiled for 6 hours. Wet oxidation was performed. Subsequently, after filtering with glass fiber and washing | cleaning with distilled water, it was made to dry with a 100 degreeC high temperature tank. The obtained oxidized carbon black l had a volatile content of 13% and a BET specific surface area of 110 m ² / g.
Next, a carbon black dispersion L was obtained in the same manner as in Preparation Example 1 except that the above oxidized carbon black l was used in place of the ozone-oxidized carbon black a in Preparation Example 1.

(Comparative Preparation Example 6) Carbon black dispersion M
Carbon black (PRINTEX-U (oil absorption amount 460 g / 100 g)) manufactured by Degussa is mixed with 500 g of distilled water, and 600 g of peroxodisulfuric acid Na aqueous solution (10%) is added dropwise with stirring, and the mixture is boiled for 6 hours and wetted. Oxidation was performed. Subsequently, after filtering with glass fiber and washing | cleaning with distilled water, it was made to dry with a 100 degreeC high temperature tank. The obtained oxidized carbon black m had a volatile content of 13% and a BET specific surface area of 110 m ² / g.
Next, a carbon black dispersion M was obtained in the same manner as in Preparation Example 1 except that the above oxidized carbon black m was used in place of the ozone-oxidized carbon black a in Preparation Example 1.

  Table 1 summarizes the carbon black adjustment examples and the comparative adjustment examples. In Table 1, “post-oxidation CB” means carbon black after oxidation.

[Examples 1-30, Comparative Examples 1-8]
Using the carbon black pigment dispersions of Preparation Examples 1-7 and Comparative Preparation Examples 1-6, a wetting agent, water, etc. were added thereto to prepare an ink. After stirring for 1 hour 30 minutes, a membrane having a pore size of 1.2 μm Filtration with a filter gave an ink for inkjet recording.
Below, the structure of the ink of Examples 1-30 is shown in Table 2-Table 5, and the structure of the ink of Comparative Examples 1-8 is shown in Table 6. In addition, the numerical value in a table | surface shows the mass%.

Here, the abbreviations in Tables 2 to 6 mean the following.
Acrylic-silicone resin emulsion: Showa Polymer Co., Ltd., Polysol ROY6312, solid content 37.2%, average particle diameter 171 nm, minimum film-forming temperature (MFT) 20 ° C.
FS-300: polyoxyethylene perfluoroalkyl ether (Dupont, 40% component)
Proxel GXL: Antifungal agent based on 1,2-benzisothiazolin-3-one (Avicia, 20% component, containing dipropylene glycol)

  Next, each ink for inkjet recording of Examples 1-30 and Comparative Examples 1-8 was evaluated by the evaluation method shown below. The results are shown in Table 7.

<Storage stability evaluation>
Each ink was filled in an ink cartridge and stored at 60 ° C. for 2 weeks, and the change in viscosity after storage with respect to the viscosity before storage was evaluated according to the following criteria. The smaller the value of the viscosity change rate, the better. The viscosity change rate was determined by the formula “viscosity change rate (%) = (viscosity after storage−viscosity before storage) × 100 / viscosity before storage”.
[Evaluation criteria]
○: Change in viscosity is within ± 10% △: Change in viscosity is within ± 30% ×: Change in viscosity exceeds 30%

<Image density>
A chart with a 64 point character “■” written in Microsoft Word 2000 (manufactured by Microsoft) filled with ink prepared in an ink jet printer (manufactured by Ricoh, IPSiO GX5000) in a 23 ° C. and 50% RH environment on paper (MyPaper, manufactured by Ricoh Co., Ltd.), the “■” portion of the printed surface was measured with X-Rite 938, and judged according to the following evaluation criteria.
The printing mode used was a driver attached to the printer, in which the "plain paper-standard fast" mode was changed to "no color correction" from the user setting for plain paper.
〔Evaluation criteria〕
◎: 1.35 or more ○: 1.25 or more Δ: 1.15 or more ×: less than 1.15

<Ink ejection stability>
Filled with ink created on an inkjet printer (Ricoh, IPSiO GX5000) under 32 ° C, 15% RH environment, and 5 sets of 200 sheets of paper (MyPaper, manufactured by Ricoh) are continuously set at a resolution of 600 dpi. Was printed. Discharge turbulence and non-discharge conditions at this time were evaluated according to the following criteria.
In addition, the printing pattern was printed with 100% duty for each ink in a chart in which each color printing area was 5% in the total area of the paper surface created by Microsoft Word 2000 (manufactured by Microsoft). The printing conditions were a recording density of 300 dpi and one-pass printing.
[Evaluation criteria]
◎: Discharge turbulence and non-ejection are not observed ○: Discharge turbulence is slight, but can be used in actual use △: Slight non-ejection and discharge turbulence are observed ×: Remarkable non-ejection and discharge turbulence are observed

<Drying>
A chart is printed out in the same manner as in the case of the image density described above, and the “■” portion of the printed surface printed on paper (Type 6200, manufactured by Ricoh) is printed immediately after printing. 2 Filter paper was pressed and judged by the presence or absence of transfer.
〔Evaluation criteria〕
◎: No transfer stains ○: Slight transfer stains are possible in actual use △: Transfer stains ×: Significant transfer stains

As seen in Table 7, it can be seen from the comparison between Examples 1 to 5 and Comparative Examples 1 and 2 that the wetting agent of the present invention has a high image density and is excellent.
Moreover, it is understood from the comparison between Examples 1 to 5 and Comparative Examples 7 and 8 that the ozone-oxidized carbon of the present invention is excellent in storage stability and ink discharge performance.
Further, from comparison between Examples 6 to 11 and Comparative Examples 3 to 6, it can be seen that the BET specific surface area and the volatile content are within the scope of the present invention, and both the image density and the storage stability can be achieved.
Moreover, it turns out from the comparison of Examples 12-30 and Examples 1-11 that the combined use of the wetting agent according to claim 2 is excellent in image density.

  As described above, the combination of the ozone-oxidized carbon black and the wetting agent of the present invention has good ink storage stability, high image density is obtained on plain paper, and ink ejection stability is good. In addition, an ink cartridge, an ink jet recording method, an ink jet recording apparatus, and an ink recorded matter using the ink can be provided.

DESCRIPTION OF SYMBOLS 101 Main body 102 Paper feed tray 103 Paper discharge tray 104 Ink cartridge loading part 111 Upper cover 112 Front surface 115 Front cover 131 Guide rod 132 Stay 133 Carriage 134 Recording head 135 Sub tank 141 Paper mounting part 142 Paper 144 Separation pad 151 Conveying belt 152 Counter roller 156 Charging roller 157 Transport roller 158 Densation roller 171 Separation claw 172 Paper discharge roller 173 Paper discharge roller 181 Double-sided paper feed unit 200 Ink cartridge 241 Ink bag 242 Ink inlet 243 Ink outlet 244 Cartridge exterior

JP 2008-163238 A JP 2000-319572 A JP 2004-224955 A JP 2001-164148 A JP-A-10-251575

Claims (6)

In an inkjet recording ink comprising at least water, a wetting agent, and a colorant, the wetting agent is isopropylideneglycerol represented by the following (formula 1) and 3-ethyl-3- 3 represented by the following (formula 2). It contains at least one of hydroxymethyloxetane, and the colorant is carbon black having a BET specific surface area of 90 to 150 m ² / g and ozone-oxidized carbon black having a volatile content of 10 to 20% by mass. Ink for inkjet recording.
The ink for inkjet recording according to claim 1, wherein the wetting agent is selected from the following (1), (2), (3), and (4).
(1) Wetting agent comprising a combination of isopropylideneglycerol and glycerin (2) Wetting agent comprising 3-ethyl-3-hydroxymethyloxetane and glycerin (3) Wetting comprising a combination of the following (i) and (ii) Agent (i) Isopropylideneglycerol and glycerin (ii) At least one selected from 3-ethyl-3-hydroxymethyloxetane, 1,3-butanediol, 3-methyl-1,3-butanediol and 2-pyrrolidone (4) Wetting agent comprising a combination of (iii) and (iv): (iii) 3-ethyl-3-hydroxymethyloxetane and glycerin (iv) 1,3-butanediol, 3-methyl-1,3- At least one selected from butanediol and 2-pyrrolidone   An ink cartridge comprising the ink jet recording ink according to claim 1 or 2 in a container.   An ink jet recording method comprising at least an ink flying step of recording an image by applying a stimulus to the ink for ink jet recording according to claim 1 and causing the ink for ink jet recording to fly.   An ink jet recording apparatus comprising at least an ink flying unit that records an image by applying a stimulus to the ink for ink jet recording according to claim 1 and causing the ink for ink jet recording to fly.   An ink recorded matter comprising an image recorded with the ink for ink jet recording according to claim 1 on a recording medium.