JP5317482B2 - Aqueous ink, ink jet recording method, ink cartridge, recording unit, ink jet recording apparatus, and image - Google Patents

Abstract

Provided is an aqueous ink, ink jet recording method, ink cartridge, recording unit, ink jet recording apparatus, and image with high storage stability and scratch resistance at such a high level that the coloring material of an image is not scraped off even when lightly touched with a sharp product. The aqueous ink includes a water-insoluble coloring material and plural polymers. The plural polymers include a polymer A which relatively contributes to dispersion of the water-insoluble coloring material and a polymer B which does not relatively contribute to the dispersion of the water-insoluble coloring material compared to the polymer A. The polymer A includes a block copolymer having an acid value of 120 mgKOH/g to 180 mgKOH/g and having an ethylene oxide group as a nonionic group. The polymer B has an acid value of 150 mgKOH/g or less and a hydrogen bond parameter (deltah) of the polymer obtained by solubility parameters of monomers constituting the polymer of 1.0 cal<0.5>/cm<1.5 >or more and 3.2 cal<0.5>/cm<1.5 >or less.

Description

  The present invention relates to a water-based ink using a water-insoluble color material as a color material, and an ink jet recording method, an ink cartridge, a recording unit, an ink jet recording apparatus, and an image using the water-based ink.

  Ink coloring materials used for ink jet recording mainly include dyes and pigments. Conventionally, dyes have been mainly used for easy handling as water-based inks and high color developability of formed images. Met. However, in recent years, water-based pigment inks using pigments as colorants have been developed for the purpose of further improving the weather resistance of images. In this pigment ink, a resin dispersant (hereinafter sometimes referred to as a dispersant) or the like is widely used as a dispersant for a water-insoluble pigment.

  However, although the image formed with the pigment ink is superior in weather resistance as compared with the image formed with the dye ink, there is a problem that the scratch resistance is low. In order to solve this problem, there is a proposal related to devising a water-soluble resin to be contained in ink (see Patent Document 1).

JP-A-8-269374

  However, the scratch resistance required for images displayed outdoors, such as posters, panels, signs, pop advertisements, etc., is required for conventional recorded materials. This level is insufficient, and a high level of scratch resistance is required. For example, for printing posters and advertisements, a large recording medium such as A0 size or A1 size is often used. When carrying a recording medium on which an image is formed, it is generally rolled up into a cylindrical shape. Is. When the recording medium is rolled, the image may be rubbed with a sharp portion such as a corner of the recording medium. At this time, even when the conventional pigment ink, which is said to satisfy the scratch resistance of the image at a high level, is used, the formed image is scratched and the color material is scraped off. With conventional pigment inks, this problem occurs quite often.

  The same problem as described above also occurs in other situations. For example, when an image formed with pigment ink is pasted outdoors as a poster, the image can be touched lightly with a sharp object such as a nail. At this time, similarly to the above, the problem that the color material of the image formed with the pigment ink is scraped off occurs with considerable frequency. In this way, particularly when pigment ink is selected as the ink used in a large-format ink jet recording apparatus, even if the image is touched with sharp objects such as corners or nails of the recording medium, the color material of the image is scraped off. There is a need for higher scratch resistance than conventional. In the expansion of the use of ink-jet recorded images, the above problem has become a major problem in pigment inks.

  In the past, scratch resistance of images formed with pigment ink has been a problem, and various methods have been proposed to solve this problem. However, many of them have been studied for small-sized ink jet recording apparatuses used for offices and homes, so that only using conventional technology does not damage the recording medium with a finger. It is best to obtain a scratch-resistant image. That is, the problem of scratch resistance of an image formed with pigment ink when a sharp object such as a corner or nail of a recording medium touches the image still cannot be solved.

  In order to improve the scratch resistance of the image formed with the pigment ink in response to such a problem, a dispersant or the like is contained in the ink so that the pigment constituting the image is firmly fixed by the recording medium. It is conceivable to contain a large amount of this resin. However, when an excessive amount of resin or the like is added to the ink, the dispersion stability of the pigment in the ink, the storage stability of the ink, or the ejection stability of the ink is reduced. A problem may occur.

  Accordingly, an object of the present invention is to solve the above-described problems of water-based ink using a water-insoluble color material such as a pigment as a color material. Specifically, an image having a high level of scratch resistance that satisfies the storage stability of the ink and does not scrape off the coloring material even when the image is lightly touched with a sharp object such as a nail. An object of the present invention is to provide an aqueous ink that can be formed. Another object of the present invention is an ink jet recording method, an ink cartridge, a recording unit, an ink jet recording apparatus, and the water-based ink that can stably obtain the above-described excellent image having high scratch resistance. Is to provide an image.

  As a result of the study by the present inventors, it has been found that the above-described problem of the present invention cannot be solved only by the constitution of ink containing one type of dispersant. Therefore, the present inventors, in the configuration of an ink containing a plurality of resins having different characteristics, the plurality of resins have different functions with respect to the color material in the ink, that is, the plurality of resins are functionally separated. We examined based on the new idea of making it happen. As a result, the resin A, which has a relatively high contribution to the dispersion of the water-insoluble colorant, and the scratch resistance of the image although the contribution to the dispersion of the water-insoluble colorant is relatively low compared to the resin A. It was found that by using together the resin B that can contribute to the above, it is possible to achieve both high scratch resistance and storage stability.

That is, the present invention is an inkjet water-based ink containing at least a water-insoluble colorant and a plurality of resins, wherein the plurality of resins include a resin A and a resin B, and the water-based ink is discharged at 20,000 rpm. The resin A is detected more than the resin B in the sediment when centrifuged for 2 hours, and the resin A has an acid value of 120 mgKOH / g or less and 180 mgKOH / g or less. A block copolymer having an ethylene oxide group as a functional group, wherein the resin B has an acid value of 90 mgKOH / g or more and 150 mgKOH / g or less, and is calculated from a solubility parameter of a monomer constituting the resin. aqueous Lee, characterized in that hydrogen bond (.delta.h) is 1.0 cal ^0.5 / cm ^1.5 or more 3.2cal ^0.5 / cm ^1.5 or less A click.

  Another embodiment of the present invention is an ink jet recording method in which ink is ejected by an ink jet method to perform recording on a recording medium, wherein the ink is the water-based ink described above. It is.

  Another embodiment of the present invention is an ink cartridge including an ink storage portion that stores ink, wherein the ink stored in the ink storage portion is the water-based ink described above. Ink cartridge.

  Another embodiment of the present invention is a recording unit comprising an ink containing portion that contains ink and a recording head that ejects ink, wherein the ink contained in the ink containing portion is The recording unit is a water-based ink.

  Another embodiment of the present invention is an ink jet recording apparatus that includes an ink storage unit that stores ink and a recording head that discharges ink, and the ink stored in the ink storage unit includes: An ink jet recording apparatus comprising the water-based ink described above.

  Another embodiment of the present invention is an image formed on a recording medium by ejecting ink by an ink jet method, wherein the ink is the water-based ink described above.

  According to the present invention, the ink storage stability is satisfied, and even when the image is rubbed with a finger, the color material is not scraped off even when the image is lightly touched with a sharp object such as a nail. Provided is a water-based ink using a water-insoluble colorant capable of obtaining scratch resistance. According to another embodiment of the present invention, an ink jet recording method, an ink cartridge, a recording unit, an ink jet recording apparatus, and an image formed using the water-based ink can stably obtain the excellent image. Is provided.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In addition, although a pigment is mentioned and demonstrated as a typical example of a water-insoluble color material, this invention is not limited to this. In the following description, “water-based ink” and “pigment ink” may be simply referred to as “ink”.

  First, the inventors of the present invention, as the level of scratch resistance of an image formed with the pigment ink intended by the present invention, of course, when the image is rubbed with a finger, lightly touching with a sharp object such as a nail. So, we set the standard that the coloring material is not scraped off. If the image satisfies this standard, sufficient scratch resistance can be realized even in applications such as posters and pop advertisements displayed outdoors. Therefore, the present inventors have studied a resin to be contained in the ink in combination with the resin dispersant so that the image formed with the ink satisfies the high scratch resistance as described above. went. As a result, it has been found that a resin having such a function needs to remain on the recording medium and form a film without penetrating into the recording medium together with the aqueous medium in the ink. Obtained. Furthermore, it has been found that a resin satisfying the following two conditions is necessary in order to cause the phenomenon described above when recording is performed by applying pigment ink to an ink jet system. . That is, when selecting a resin to be included in the ink that can contribute to the scratch resistance of the image, the hydrogen bond term (δh) of the resin calculated from the acid value of the resin and the solubility parameter of the monomer constituting the resin. We came to the conclusion that it is important to consider two conditions.

  First, the hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin, which is one condition in selecting a resin that can contribute to the scratch resistance of the image by being contained in the ink, The relationship with the scratch resistance of the image will be described. The hydrogen bond term which is a problem in the present invention is derived from hydrogen bonds, and if the value of the hydrogen bond term of the resin increases, the affinity between the resin and water tends to increase. Ink mainly containing an aqueous medium, such as an aqueous ink for inkjet, tends to reduce the cohesiveness between resins as the hydrogen bond term of the resin increases. Along with this, the resin does not aggregate on the recording medium and easily penetrates into the recording medium, and the ratio of the resin remaining on the recording medium tends to decrease. For this reason, it is considered that when the hydrogen bond term of the resin contained in the water-based ink is increased, the effect of improving the scratch resistance of the formed image is not exhibited.

This will be described more specifically with reference to the drawings. FIG. 1 is a schematic diagram showing a state in which a resin having a hydrogen bond term calculated from the solubility parameter of the monomer constituting the resin exceeds 3.2 cal ^0.5 / cm ^1.5 is dissolved in an aqueous medium. FIG. 2 is a schematic diagram showing a state in which a resin having a hydrogen bond term of 3.2 cal ^0.5 / cm ^1.5 calculated from the solubility parameter of the monomer constituting the resin penetrates the recording medium D. FIG. FIG. 3 is a schematic diagram showing how a resin having a hydrogen bond term of 3.2 cal ^0.5 / cm ^1.5 or less calculated from the solubility parameter of the monomer constituting the resin is dissolved in an aqueous medium. . FIG. 4 is a schematic diagram showing a state in which a resin having a hydrogen bond term of 3.2 cal ^0.5 / cm ^1.5 or less calculated from the solubility parameter of the monomer constituting the resin aggregates on the recording medium D.

As shown in FIG. 1, since the hydrogen bond term of the resin calculated from the solubility parameter of the monomer constituting the resin exceeds 3.2 cal ^0.5 / cm ^1.5 has a large hydrogen bond term, only the hydrophilic part B of the resin is present. But also hydrates to the hydrophobic part C of the resin. In addition, A in a figure represents a water molecule. As a result, when an ink containing such a resin is applied to the recording medium D, hydrophilicity is maintained even if the resin content is relatively higher than before evaporation due to evaporation of the aqueous medium in the ink. Water molecules A are hydrated in part between the sex parts B. For this reason, as shown in FIG. 2, the cohesiveness between the resins tends to decrease, and the resin does not aggregate on the recording medium D and easily penetrates into the recording medium D. The amount of remaining resin is reduced. As a result of the study by the present inventors, when the hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin exceeds 3.2 cal ^0.5 / cm ^1.5 , the above tendency becomes remarkable and sufficient resistance to resistance is obtained. It has been found that images showing scratching properties may not be obtained.

On the other hand, as shown in FIG. 3, since the resin hydrogen bond term calculated from the solubility parameter of the monomer constituting the resin is 3.2 cal ^0.5 / cm ^1.5 or less, the hydrogen bond term is small. Hydration of water molecule A to C hardly occurs. As a result, when an ink containing such a resin is applied to the recording medium D, the resin content may be increased even if the resin content is relatively higher than before evaporation due to evaporation of the aqueous medium in the ink. Since the influence of hydration of water molecules A on the hydrophilic portion B of the resin is small, the aggregation of the resin is not suppressed. For this reason, as shown in FIG. 4, the aggregation of the resins proceeds, and a large amount of the resin remains on the recording medium D. As a result, an image showing sufficient scratch resistance can be obtained.

Further, as a result of the study by the present inventors, the resin contained in the ink used for ink jet recording has a hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin of 1.0 cal ^0.5 / cm. It turns out that it is necessary to be ^1.5 or more. This is because, when the hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin is less than 1.0 cal ^0.5 / cm ^1.5 , the discharge port wetting phenomenon due to the resin occurs remarkably. There is. As a result, the ink ejection characteristics may be deteriorated, for example, the flight of the ink droplet may be bent.

  Next, the relationship between the acid value of the resin and the scratch resistance of the image, which is another condition when selecting a resin that can be included in the ink and can contribute to the scratch resistance of the image, will be described. According to the study by the present inventors, it has been found that the above resin satisfies the above-mentioned range of the hydrogen bond term (δh), and further the acid value of the resin needs to be 150 mgKOH / g or less. . When the acid value of the resin is 150 mgKOH / g or less, the object of the present invention is to obtain a high level of scratch resistance that prevents the coloring material from being scraped off even when the image is lightly touched with a sharp object such as a nail. It becomes possible. On the other hand, when the acid value of the resin exceeds 150 mgKOH / g, the anionic groups of the resin increase, and the buffering action on salts and protons on the recording medium increases. As a result, the above-described aggregation of the resin on the recording medium is suppressed, the ratio of the resin remaining on the recording medium is reduced, and high image scratch resistance may not be obtained.

  Further, if the acid value of the resin that can contribute to image scratch resistance is less than 90 mgKOH / g, the resin may precipitate when the resin cannot be dissolved with an alkali or when the ink is stored for a long period of time. Ink storage stability may not be sufficiently obtained due to an increase in particle size. Furthermore, when the acid value is less than 90 mgKOH / g, it is used as an ink sufficient to obtain the high scratch resistance intended by the present invention, and when ejected by an ink jet method utilizing thermal energy, stable ejection properties are obtained. It may be difficult to maintain. Therefore, the acid value of the resin that can contribute to the scratch resistance of the image is more preferably 90 mgKOH / g or more.

As described above, in order to improve the scratch resistance of an image formed with an ink containing a water-insoluble colorant such as a pigment, the ink should contain a resin that satisfies the above two conditions. Is effective. That is, the acid value of the resin is 150 mgKOH / g or less, and the hydrogen bond term of the resin calculated from the solubility parameter of the monomer constituting the resin is 1.0 cal ^0.5 / cm ^1.5 or more and 3.2 cal ^0.5 / cm ^1.5 or less. It is necessary to use a resin that is Furthermore, as described above, the acid value of the resin is preferably 90 mgKOH / g or more. Hereinafter, a water-insoluble colorant such as a pigment is dispersed in the ink, and it is necessary to improve the scratch resistance of the image with respect to the resin A described later having a function of relatively achieving the storage stability of the ink. A resin that satisfies the above two conditions is referred to as Resin B.

The “hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin” defined in the present invention will be described. First, the solubility parameter will be described. The solubility parameter is affected by the type of functional group in the compound. The solubility parameter is one of the factors for determining the solubility of a plurality of compounds, that is, the strength of affinity between the compounds. When the solubility parameters of each of the plurality of compounds are close, these compounds There is a tendency that the mutual solubility becomes high. The solubility parameter includes the dispersion force term (δd) due to the primary bias of the electron distribution, the polar term (δp) due to the attractive force generated by the dipole moment, and the hydrogen bonds generated by active hydrogen and lone electron pairs. It is divided into the resulting hydrogen bond term (δh). In the present invention, the solubility parameter is applied to the resin, but the greater the value of the hydrogen bond term (δh) of the resin, the greater the affinity between the resin and water. The hydrogen bond term (δh) of the resin can be calculated from the solubility parameter of the monomer constituting the resin. In that case, it can be obtained by using the atomic group summation method proposed by Krebelen, in which organic molecules are handled as atomic groups. (See Krevelen, Properties of Polymer 2nd Edition, New York, 154 (1976).) This method is as follows. First, from the dispersion force parameter Fdi per mole, the polar force parameter Fpi per mole, and the hydrogen bond strength parameter Fhi per mole of each atomic group of the organic molecule, the solubility parameter dispersion force term (δd), polarity term (δp) ), A hydrogen bond term (δh) is obtained. Then, by using these values, the solubility parameter (δ) can be obtained as in the following formula. In the present invention, as described later, the hydrogen bond term (δh) of the resin was calculated using the above-described concept and using the solubility parameter unique to each monomer constituting the resin.

  Next, resin A that can particularly contribute to the storage stability of the ink will be described. The present inventors have studied in detail about a resin that can improve the storage stability of ink. As a result, it was first found that excellent storage stability can be obtained by using a block copolymer having an ethylene oxide group as a nonionic group as a dispersant for a water-insoluble colorant.

  FIG. 5 is a schematic diagram showing the dispersion state of the water-insoluble colorant (pigment) E in the ink. (1) shows the case of a block copolymer, and (2) shows the case of a random copolymer. Indicates. When using a block copolymer as resin, the hydrophilic part B (nonionic group and / or anionic group) and the hydrophobic part C exist as a block, respectively. For this reason, as shown in (1) of FIG. 5, the adsorption of the hydrophobic portion C to the water-insoluble colorant (pigment) E becomes strong, and the spread of the hydrophilic portion B to the aqueous medium is also a random copolymer. It becomes larger than the case of (2) using. Therefore, by using a block copolymer, the effect of dispersion due to the three-dimensional structure of the resin is great, and as a result, aggregation of water-insoluble colorants is less likely to occur. At this time, when a block copolymer having a nonionic group is used, even if the dispersion stability due to electrostatic repulsion of the anionic group is reduced by an external factor such as a salt or pH change, the resin is nonionic. Since it has a group, the dispersion stability in the ink is extremely high.

  Based on the above, the present inventors have developed a resin that is a block copolymer having a nonionic group that functions well as a dispersant for the water-insoluble colorant and the resin B that improves image scratch resistance. It was considered that the object of the present invention can be achieved by the constitution of the ink having both.

  However, as a result of further studies by the present inventors, a high image resistance, which is the object of the present invention, can be obtained simply by using a resin that is a block copolymer having a nonionic group in combination with the resin B described above. It has been found that there are cases where the scratch resistance and the storage stability of the ink cannot be compatible. That is, it has been found that the use of both types of resins as constituent components of the ink causes a new problem that the properties inherent to each other resin may not be exhibited. Therefore, the present inventors further examined the cause of the above problem. As a result, it was found that the degree of compatibility between these resins is greatly related to the compatibility between high image scratch resistance and ink storage stability. That is, it was found that if the compatibility of the resins is too small, the properties of each other may be canceled out, and as a result, all of the properties inherent to each resin may not be exhibited.

  Therefore, the present inventors have searched for a resin that is a block copolymer having a nonionic group that is compatible with the resin B. As a result, it was found that the resin A, which is a block copolymer having an acid value of 120 mgKOH / g or more and 180 mgKOH / g or less and having an ethylene oxide group as a nonionic group, is highly compatible with the resin B. . Further, in order to achieve both high image scratch resistance and good ink storage stability, which is the object of the present invention, among the two types of resins described above, the resin A is relatively free from dispersion of the water-insoluble colorant. It was found that it was necessary to contribute to the present invention, and the present invention was made.

  In the present invention, it can be determined by the following method whether the resin A in the ink contributes relatively to the dispersion of the water-insoluble colorant as compared to other resins used together. First, by centrifuging the ink, it is divided into a component containing a water-insoluble colorant as a sediment and a water-soluble component as a supernatant, and analysis of the resin present in the component containing the water-insoluble colorant is as follows. Do as follows. The centrifugation conditions at this time are preferably 20,000 rpm and 2 hours, but the present invention is not limited to this. The component containing the water-insoluble colorant separated by centrifugation is dispersed again in water, and hydrochloric acid or the like is added thereto for acid precipitation. The precipitate is separated by centrifugation or filtration to obtain a solid. This solid is subjected to Soxhlet extraction with an organic solvent such as tetrahydrofuran (THF) to obtain a resin. Then, the obtained resin is analyzed by NMR measurement or the like. By such a method, it is possible to determine which resin was relatively adsorbed to the water-insoluble color material, and to determine which resin contributed relatively to the dispersion of the water-insoluble color material.

[Water-based ink]
Hereinafter, each component constituting the inkjet aqueous ink of the present invention (sometimes simply referred to as “ink”) will be described.
<Resin A>
In the present invention, as described above, the resin A which is a block copolymer having an acid value of 120 mgKOH / g to 180 mgKOH / g and having an ethylene oxide group as a nonionic group is used. The resin A needs to be a block copolymer. Examples of the method for obtaining the block copolymer include a living anion polymerization method using n-butyllithium or the like as a polymerization initiator, a method by polymerization of a macromonomer and another monomer, and group transfer polymerization. Of course, the present invention is not limited to these.

  The monomer for forming the resin A only needs to contain a monomer having an ethylene oxide group as a nonionic group, and any other monomer may be used. As monomers other than the monomer having an ethylene oxide group, for example, the following can be used. Styrenes such as styrene and o-methylstyrene. (Meth) acrylic acid esters such as methyl methacrylate and benzyl methacrylate. (Meth) acrylic esters having a nonionic group such as polyoxyethylene. And monomers having an unsaturated group having an anionic group such as acrylic acid, methacrylic acid and maleic acid.

  The ratio of the ethylene oxide group constituting the resin A based on the total mass of the resin A (the mass of the ethylene oxide group / the total mass of the resin A) is preferably 10% by mass or more and 40% by mass or less. If the proportion of the ethylene oxide group is less than 10% by mass, the degree of contribution of the nonionic group to the dispersion of the water-insoluble colorant is lowered, and the dispersion stability may be lowered. On the other hand, when the proportion of the ethylene oxide group exceeds 40% by mass, the affinity between the resin and water is increased, and depending on the content of the resin in the ink, the scratch resistance of the image may be lowered.

  The weight average molecular weight of the resin A is preferably 2,000 or more and 15,000 or less, and more preferably 3,000 or more and 6,000 or less. If the weight average molecular weight is less than 2,000, the scratch resistance of the image may be slightly lowered. On the other hand, if the weight average molecular weight exceeds 15,000, the storage stability of the ink may decrease. In addition, although mentioned later for details, it is preferable that the weight average molecular weight of resin A is smaller than the weight average molecular weight of resin B used together.

  The content (% by mass) of the resin A in the ink is preferably 0.10% by mass or more and 5.00% by mass or less based on the total mass of the ink. Further, the content (mass%) of the resin A based on the total mass of the ink is (content of the resin A / water insoluble) with respect to the content (mass%) of the water-insoluble colorant based on the total mass of the ink. The content of the coloring material) is preferably 0.20 times or more. Further, the content (mass%) of the resin A based on the total mass of the ink is (content of the resin A / water insoluble) with respect to the content (mass%) of the water-insoluble colorant based on the total mass of the ink. Colorant content), 2.16 times or less, and more preferably 2.00 times or less. By setting the ratio of the content of the resin A and the content of the water-insoluble colorant within the above range, the dispersion stability of the water-insoluble colorant in the ink can be further increased, and the storage stability of the ink is also improved. This is because it can be increased.

<Resin B>
The ink of the present invention comprises the resin A described above and the resin B as described below in combination. As a first condition, the resin B needs to have an acid value of 150 mgKOH / g or less. At the same time, as the second condition, the resin B has a hydrogen bond term (δh) calculated from the solubility parameter of the monomer constituting the resin, 1.0 cal ^0.5 / cm ^1.5 or more and 3.2 cal ^0.5 / cm ^1.5 or less. It is necessary to be. If these conditions are satisfied, the monomer constituting the resin B, the ratio of each monomer, and the like can be appropriately determined without particular limitation. In addition, as described above, in consideration of the storage stability of the ink and the stable ejection property in the ink jet method using thermal energy, the acid value of the resin B is more preferably 90 mgKOH / g or more. Further, according to the study by the present inventors, in order to further improve the scratch resistance of the image, it is preferable to use a resin that satisfies the following conditions as the resin B. That is, when a hydrophobic monomer is used as a component of the resin B and the hydrogen bond term (δh) of the hydrophobic monomer calculated from the solubility parameter is 2.8 cal ^0.5 / cm ^1.5 or less, the scratch resistance of the image The sex can be further improved.

  The “hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin” defined in the present invention is a value specifically determined as follows. First, for each monomer constituting the target resin, the hydrogen bond term (δh) of each monomer constituting the resin is calculated from the solubility parameter specific to the monomer. Next, the value obtained by multiplying the hydrogen bond term (δh) of each monomer constituting the resin obtained above by the composition (mass) ratio of each monomer constituting the resin (composition ratio with the sum being 1), respectively. Further, the hydrogen bond term (δh) of the resin is obtained by adding the obtained values.

In the resin B used in the present invention, the value of the hydrogen bond term (δh) of the resin calculated as described above from the solubility parameter of the monomer constituting the resin is 1.0 cal ^0.5 / cm ^1.5 or more. 2 cal ^0.5 / cm ^1.5 or less is required. In the present invention, each monomer constituting the resin B is also preferably configured such that the value of the hydrogen bond term (δh) of the monomer calculated from the solubility parameter is within the above range.

In the ink of the present invention, particularly when a resin composed of a specific hydrophobic monomer is used, the scratch resistance of the formed image can be further improved. Specifically, when a hydrophobic monomer is used as a constituent component of the resin B and the hydrogen bond term (δh) of the hydrophobic monomer calculated from the solubility parameter is 2.8 cal ^0.5 / cm ^1.5 or less, The scratch resistance of the image is further improved. Here, the hydrophobic monomer in the present invention is a monomer having a solubility in water of 5 g or less per 100 g of water. If the said conditions are satisfy | filled, any thing can be used for a hydrophobic monomer without a restriction | limiting in particular.

However, since the resin B has a hydrogen bond term (δh) value calculated from the solubility parameter of the monomer constituting the resin of 1.0 cal ^0.5 / cm ^1.5 or more and 3.2 cal ^0.5 / cm ^1.5 or less, The hydrophobic monomers constituting B are preferably as follows. As the hydrophobic monomer constituting the resin B, a monomer having a hydrogen bond term of the monomer calculated from the solubility parameter of the monomer within a range of 3.2 cal ^0.5 / cm ^1.5 or less is preferably used. Further, it is more preferable to use a hydrophobic monomer having a hydrogen bond term of the monomer calculated from the solubility parameter of the monomer of 2.8 cal ^0.5 / cm ^1.5 or less. Further, it is preferable to use a hydrophobic monomer having a hydrogen bond term of the monomer calculated from the solubility parameter of 0.0 cal ^0.5 / cm ^1.5 or more. Examples of the hydrophobic monomer suitable for the present invention in which the hydrogen bond term of the hydrophobic monomer calculated from the solubility parameter is 0.0 cal ^0.5 / cm ^1.5 or more and 3.2 cal ^0.5 / cm ^1.5 or less include the following. . For example, styrene, α-methylstyrene, ethyl acrylate, n-butyl acrylate, n-hexyl acrylate, benzyl methacrylate and the like. When the monomers constituting the hydrophobic portion of the resin is 2 or more, the weighted average of the hydrogen bond of each monomer is 3.2cal ^0.5 / cm ^1.5 or less, and more preferably 2.8cal ^0.5 / cm ^1.5 or less What is necessary is just to select and use.

  Examples of the monomer other than the hydrophobic monomer that can be used as a constituent component of the resin B include an acrylic monomer having an anionic group. Specifically, the following monomers can be used. Monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, ethacrylic acid, propylacrylic acid, isopropylacrylic acid, itaconic acid and fumaric acid. Monomers having a sulfonic acid group such as styrene sulfonic acid, sulfonic acid-2-propylacrylamide, acrylic acid-2-ethyl sulfonate, methacrylic acid-2-ethyl sulfonate, and butylacrylamide sulfonic acid. A monomer having a phosphonic acid group such as ethyl methacrylic acid-2-phosphonate or ethyl acrylate-2-phosphonate can be used.

  In the present invention, for example, an acrylic resin can be used as the resin B. This acrylic resin contains, for example, an acrylic monomer and a radical polymerization initiator as described above in an organic solvent such as xylene. It can be obtained by polymerization. As the polymerization initiator in this case, an azo initiator, a peroxide initiator, or the like can be used.

  According to the study by the present inventors, when the monomer constituting the resin B used in the ink of the present invention contains at least n-butyl acrylate, the compatibility between the resin B and the resin A is increased, and the ink is stored. It is preferable because stability and image scratch resistance can be further improved. Furthermore, by using a copolymer in which the hydrophobic portion of the resin B has both n-butyl acrylate and styrene, a more excellent ink can be obtained particularly in improving the scratch resistance of the image. At this time, it is preferable to use the following resin B for the copolymerization ratio of styrene and n-butyl acrylate. That is, among the monomers constituting the resin B, the mass ratio of n-butyl acrylate based on styrene (n-butyl acrylate / styrene) is preferably in the range of 0.10 to 0.50. Furthermore, it is particularly preferable that the mass ratio of n-butyl acrylate based on styrene (n-butyl acrylate / styrene) is larger than 0.25 and smaller than 0.35.

  The weight average molecular weight of the resin B used in the present invention is preferably larger than the weight average molecular weight of the resin A. If the weight average molecular weight of the resin B is the same as or smaller than the weight average molecular weight of the resin A, the scratch resistance of the image may not be sufficiently obtained. Similar to the behavior of the resin when the hydrogen bond term of the resin calculated from the solubility parameter of the monomer constituting the resin is large as described in the explanation of FIG. 2, the resin B penetrates into the recording medium. This is because the amount of the resin B remaining on the recording medium may be small. At this time, the weight average molecular weight of the resin B is preferably 5,000 or more. This is because if the weight average molecular weight is less than 5,000, the cohesiveness between the resins tends to be small, and the image scratch resistance may not be sufficiently obtained for the same reason as described above.

  Furthermore, the weight average molecular weight of the resin B used in the present invention is more preferably 5,000 or more and 15,000 or less, and further preferably 6,000 or more and 9,000 or less. If the weight average molecular weight is less than 5,000, as described above, sufficient scratch resistance may not be obtained. On the other hand, if the weight average molecular weight exceeds 15,000, the viscosity of the ink becomes high when used as an ink for ink jetting, so that the discharge stability may be lowered, which is not preferable. As described above, the weight average molecular weight of the resin B is preferably larger than the weight average molecular weight of the resin A used in combination.

  The structure of the resin B is preferably a random copolymer. Block copolymers and graft copolymers that can be applied to water-based inks generally have a hydrophobic portion and a hydrophilic portion localized in the structure, and the surface of a water-insoluble colorant such as a pigment is hydrophobic. It is sex. Therefore, if the resin structure is a graft copolymer or block copolymer, the surface of the water-insoluble colorant and the hydrophobic portion of the resin are likely to cause a hydrophobic-hydrophobic interaction. It is considered that the resin having the copolymer structure is easily adsorbed to the water-insoluble colorant. For this reason, if the structure of the resin B is a block copolymer or a graft copolymer, the resin B is more likely to be adsorbed to the water-insoluble colorant in preference to the resin A that contributes to the dispersion of the water-insoluble colorant. Become. The resin A that originally contributed to the dispersion of the water-insoluble colorant is in a free state in the ink. However, since the resin A has high hydrophilicity and low cohesion, the effect of developing the cohesion by the resin B is exhibited. In some cases, the image does not have sufficient scratch resistance. For this reason, it is more preferable that the resin B is a random copolymer.

  The content (% by mass) of the resin B in the ink is 0.5% by mass or more and 5.0% by mass or less, and further 1.0% by mass or more and 4.0% by mass or less based on the total mass of the ink. It is preferable. By making the content of the resin B in the above range, an amount that can satisfy the storage stability of the ink containing the water-insoluble colorant and can sufficiently exhibit the effect of improving the scratch resistance of the image formed with the ink. This resin can be left on the recording medium. Furthermore, since the wetting phenomenon of the discharge port by the resin can be suppressed, it is difficult to be affected by the deterioration of the discharge characteristics such as the flying bend of the ink droplet even though the ink contains the resin.

  In the composition of the ink of the present invention, the content (% by mass) of the resin B based on the total mass of the ink (based on the total mass of the ink) relative to the content (% by mass) of the water-insoluble colorant based on the total mass of the ink. (Content / content of water-insoluble colorant) is preferably 1.20 times or more. In particular, when the content of the water-insoluble colorant is 1.2% by mass or less, the content of the resin B with respect to the content of the water-insoluble colorant is preferably 3.00 times or more. As described above, the inventors presume the reason why the content of the resin B is preferably 3.00 times or more when the content of the water-insoluble colorant in the ink is small. doing.

  FIG. 6 is a schematic diagram showing a cross section of an image formed with an ink having a small content of the water-insoluble colorant E. FIG. 7 is a schematic diagram showing a cross section of an image formed with ink having a high content of the water-insoluble colorant E. As shown in FIGS. 6 and 7, an image formed with an ink having a small content of the water-insoluble colorant E has a higher water content relative to the resin than an image formed with an ink having a high content of the water-insoluble colorant E. The amount of insoluble colorant E is small. Therefore, it is considered that the effect of the water-insoluble colorant E as a filler agent is reduced and the strength of the film F made of resin is reduced. Therefore, when the content of the water-insoluble color material E is small, more resin B having the function of forming the film F is required.

  In the ink of the present invention, the content (% by mass) of the resin B based on the total mass of the ink is as follows with respect to the content (% by mass) of the water-insoluble colorant based on the total mass of the ink. It is preferable to be within the range. That is, the content (% by mass) of the resin B based on the total mass of the ink is (resin B / water-insoluble colorant) with respect to the content (% by mass) of the water-insoluble colorant based on the total mass of the ink. It is preferably 1.00 times or more and 5.00 times or less, more preferably 1.20 times or more and 5.00 times or less. In particular, when the content of the water-insoluble color material is 1.2% by mass or less, the content of the resin B is 3.00 times or more and 5.00 times or less with respect to the content of the water-insoluble color material. It is preferable that In the present invention, if at least these ranges are satisfied, it is considered that the strength of the film can be further increased by the above mechanism.

  Furthermore, the ink of the present invention is a water-insoluble colorant in which the sum of the content of resin A (% by mass) and the content of resin B (% by mass) based on the total mass of the ink is based on the total mass of the ink. It is preferable to be within the following range with respect to the content (% by mass). That is, the sum of the content (mass%) of the resin A based on the total mass of the ink and the content (mass%) of the resin B is the content (mass%) of the water-insoluble colorant based on the total mass of the ink. On the other hand, [(resin A + resin B) / water-insoluble colorant] is preferably 1.20 times or more. When the sum of the content (mass%) of the resin A and the content (mass%) of the resin B is within such a range, the resin component sufficiently includes an aggregate of water-insoluble colorants existing on the recording medium. Therefore, it is possible to obtain an ink that can further improve the scratch resistance of an image. However, since the discharge property tends to decrease when the content of the resin component in the ink becomes too large, the ratio [(resin A + resin B) / water-insoluble colorant] is 5.00 times or less. Preferably there is.

  Furthermore, the total of the content (% by mass) of the resin A and the content (% by mass) of the resin B based on the total mass of the ink is preferably 1.5% by mass or more. However, if the content of the resin component in the ink is excessively increased, the ejectability tends to decrease. Therefore, the resin A content (% by mass) and the resin B content (based on the total mass of the ink) ( The total of (mass%) is preferably 5.0 mass% or less.

  Furthermore, in order to obtain sufficient image scratch resistance, the ratio of the content of the resin A and the content of the resin B in the ink is preferably as follows. That is, the content (% by mass) of the resin B based on the total mass of the ink is (resin B / resin A), 1.0 with respect to the content (% by mass) of the resin A based on the total mass of the ink. It is preferably at least twice, and more preferably at least 1.2 times. However, in order to make the storage stability of the ink better, the content (mass%) of the resin B is (resin B / resin A) with respect to the content (mass%) of the resin A, 25 It is preferable that it is 0.0 times or less.

<Aqueous medium>
In the ink of the present invention, water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent can be used. The content (% by mass) of the water-soluble organic solvent in the ink is preferably 3.0% by mass or more and 50.0% by mass or less based on the total mass of the ink.

  The water-soluble organic solvent is not particularly limited as long as it is water-soluble, and those listed below can be used alone or in combination of two or more. Specifically, for example, the following water-soluble organic solvents can be used. C1-C4 alkyl alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol. Amides such as dimethylformamide and dimethylacetamide. Ketones or ketoalcohols such as acetone and diacetone alcohol. Ethers such as tetrahydrofuran and dioxane. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol. Alkylene glycols having 2 to 6 carbon atoms of an alkylene group such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol and the like. Alkyl ether acetates such as polyethylene glycol monomethyl ether acetate. Glycerin. Alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether. N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like.

  It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 50.0% by mass or more and 95.0% by mass or less based on the total mass of the ink.

<Water-insoluble colorant>
As the water-insoluble colorant contained in the ink of the present invention, a water-insoluble colorant that can be dispersed using a dispersant can be used. Specifically, for example, inorganic pigments such as calcium carbonate and titanium oxide, organic pigments such as phthalocyanine and quinacdrine, and carbon black can be used. The content (% by mass) of the water-insoluble colorant in the ink is from 0.1% by mass to 15.0% by mass and more preferably from 0.2% by mass to 10.0% by mass based on the total mass of the ink. Preferably there is.

For black ink, it is preferable to use carbon black such as furnace black, lamp black, acetylene black and channel black as a water-insoluble colorant. Specifically, for example, the following commercially available products can be used.
Ray Van: 1170, 1190 ULTRA-II, 1200, 1250, 1255, 1500, 2000, 3500, 5000 ULTRA, 5250, 5750, 7000 (above, made in Colombia). Black Pearls L, Legal: 330R, 400R, 660R, Mogul L, Monak: 700, 800, 880, 900, 1000, 1100, 1300, 1400, 2000, Vulcan XC-72R (above, manufactured by Cabot). Color Black: FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex: 35, U, V, 140U, 140V, Special Black: 6, 5, 4A, 4 (above, manufactured by Degussa). No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (above, manufactured by Mitsubishi Chemical).

  Also, newly prepared carbon black can be used. Of course, the present invention is not limited to these, and any conventional carbon black can be used. Further, the material is not limited to carbon black, and magnetic fine particles such as magnetite and ferrite, titanium black, and the like may be used as the water-insoluble colorant.

In the color ink, it is preferable to use an organic pigment as a water-insoluble colorant. Specifically, for example, the following can be used.
Water-insoluble azo pigments such as Toluidine Red, Toluidine Maroon, Hansa Yellow, Benzidine Yellow, and Pyrazolone Red. Water-soluble azo pigments such as Ritolol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B. Derivatives from vat dyes such as alizarin, indanthrone and thioindigo maroon. Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green. Quinacridone pigments such as quinacridone red and quinacridone magenta. Perylene pigments such as perylene red and perylene scarlet. Isoindolinone pigments such as isoindolinone yellow and isoindolinone orange. Imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange, and benzimidazolone red. Pilanthrone pigments such as pyranthrone red and pyranthrone orange. Indigo pigments, condensed azo pigments, thioindigo pigments, diketopyrrolopyrrole pigments. Flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet, etc. Of course, the present invention is not limited to these.

  Moreover, when an organic pigment is shown by a color index (CI) number, the following can be used, for example. C. I. Pigment Yellow: 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 97, 109, 110, 117, 120, 125, 128, and the like. 137, 138, 147, 148, 150, 151, 153, 154, 166, 168, 180, 185, etc. C. I. Pigment Orange: 16, 36, 43, 51, 55, 59, 61, 71, etc. C. I. Pigment Red: 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175 and the like. 176, 177, 180, 192, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 272, etc. C. I. Pigment violet: 19, 23, 29, 30, 37, 40, 50, and the like. C. I. Pigment Blue: 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, and the like. C. I. Pigment Green 7, 36, etc. C. I. Pigment brown 23, 25, 26, and the like. Of course, the present invention is not limited to these.

<Dispersant>
A resin dispersant is used as a dispersant for dispersing the water-insoluble colorant in an aqueous medium. In the present invention, the resin A described above is used as the resin dispersant. However, a resin other than the resin A may be used as a dispersant as long as the effects obtained by using these are obtained and the effects of the present invention are not impaired. When a resin other than the resin A described above is used as a dispersant, the weight average molecular weight of the dispersant other than the resin A is 1,000 or more and 30,000 or less, and further 3,000 or more and 7,000 or less. Is preferred. Specific examples of the monomer constituting the dispersant other than the resin A include the following, and examples thereof include a resin composed of at least two monomers. At this time, it is preferable that at least one of the monomers is a hydrophilic monomer. Monomers include styrene, vinyl naphthalene, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acid, acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl acetate, vinyl pyrrolidone, acrylamide, or derivatives thereof. Is mentioned. Examples of the form of the resin include a block copolymer, a random copolymer, a graft copolymer, or a salt thereof. Furthermore, natural resins such as rosin, shellac and starch may be used. These resins are soluble in an aqueous solution in which a base is dissolved, and are alkali-soluble resins.

<Other ingredients>
In addition to the above components, the ink of the present invention may contain a moisturizing solid content such as urea, urea derivatives, trimethylolpropane, trimethylolethane and the like. The content (% by mass) of the moisturizing solid content in the ink is 0.1% by mass or more and 20.0% by mass or less, and further 3.0% by mass or more and 10.0% by mass or less based on the total mass of the ink. It is preferable that

  Furthermore, when preparing the ink of the present invention, a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an oxidation agent are used as necessary to obtain an ink having a desired physical property value. Various additives such as an inhibitor and a reduction inhibitor may be contained. In particular, surfactants such as anionic surfactants, nonionic surfactants, and amphoteric surfactants can be used as the surfactant. Specifically, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenols, acetylene glycol compounds, acetylene glycol ethylene oxide adducts, and the like can be used. In the present invention, it is particularly preferable to use polyoxyethylene alkyl ethers and acetylene glycol ethylene oxide adducts as the surfactant.

[Inkjet recording method]
The ink of the present invention is particularly preferably applied to an ink jet recording method in which ink is ejected by an ink jet method to perform recording on a recording medium. Ink jet recording methods include a recording method in which ink is ejected by applying mechanical energy to ink, and a recording method in which ink is ejected by applying thermal energy to ink. In particular, the ink of the present invention can be particularly preferably applied to an ink jet recording method using thermal energy.

[ink cartridge]
An ink cartridge according to the present invention includes an ink storage portion that stores ink, and the ink stored in the ink storage portion is the ink of the present invention.

[Recording unit]
The recording unit of the present invention is a recording unit comprising an ink storage portion that stores ink and a recording head that discharges ink, and the ink stored in the ink storage portion is the ink of the present invention. It is characterized by being. In particular, the recording head is more preferably a recording unit that ejects ink by applying thermal energy to the ink.

[Inkjet recording apparatus]
The ink jet recording apparatus of the present invention is an ink jet recording apparatus comprising an ink storage portion for storing ink and a recording head for discharging ink, wherein the ink stored in the ink storage portion is the above-described aspect of the present invention. It is characterized by being the ink of this. In particular, the recording head is more preferably an ink jet recording apparatus that ejects ink by applying thermal energy to the ink.

  An example of an ink jet recording apparatus that can use the ink of the present invention will be described below, but the ink of the present invention can be applied to any type of ink jet recording method. First, an ink jet recording apparatus of an ink jet recording method using thermal energy will be described. An example of the configuration of the recording head, which is the main part of the apparatus, is shown in FIGS. 8 is a cross-sectional view of the recording head 13 along the ink flow path, and FIG. 9 is a cross-sectional view taken along the line AB of FIG. The recording head 13 includes a member having an ink flow path (nozzle) 14 and a heating element substrate 15. The heating element substrate 15 includes a protective layer 16, electrodes 17-1 and 17-2, a heating resistor layer 18, a heat storage layer 19, and a substrate 20.

  When pulsed electric signals are applied to the electrodes 17-1 and 17-2 of the recording head 13, the region indicated by n of the heating element substrate 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact with the surface. Will occur. Then, the meniscus 23 protrudes due to the pressure of the bubbles, and the ink 21 is ejected as an ink droplet 24 from the ejection port 22 of the nozzle 14 toward the recording medium 25.

  FIG. 10 is an external view of an example of a multi-head in which a large number of recording heads shown in FIG. 8 are arranged. The multi-head includes a glass plate 27 having multi-nozzles 26 and a recording head 28 similar to that shown in FIG.

  FIG. 11 is a perspective view showing an example of an ink jet recording apparatus incorporating the recording head as described above. The blade 61 is a wiping member, one end of which is held by a blade holding member, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head 65 and is held in a form protruding in the moving path of the recording head 65.

  Reference numeral 62 denotes a cap on the ejection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, abuts on the ink ejection port surface, and performs capping. The structure to perform is provided. An ink absorber 63 provided adjacent to the blade 61 is held in a form protruding in the moving path of the recording head 65, similarly to the blade 61. The ejection recovery unit 64 includes a blade 61, a cap 62, and an ink absorber 63. The blade 61 and the ink absorber 63 remove moisture, dust, and the like from the discharge port surface.

  Reference numeral 65 denotes a recording head which has discharge energy generating means and performs recording by discharging ink onto a recording medium facing the discharge port surface where the discharge port is arranged. Reference numeral 66 denotes a movement of the recording head 65 by mounting the recording head 65. It is a carriage for performing. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 (not shown) driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and the area adjacent thereto can be moved.

  Reference numeral 51 denotes a paper feeding unit for inserting a recording medium, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, the recording medium is fed to a position facing the ejection port surface of the recording head 65 and discharged to a paper discharge unit having a paper discharge roller 53 as recording progresses. When recording by the recording head 65 is completed and the recording head returns to the home position, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 protrudes into the movement path. . In this way, the ejection port of the recording head 65 is wiped.

  When the cap 62 is in contact with the ejection port surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head. When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as in wiping. As a result, the ejection port surface of the recording head 65 is wiped even during this movement. The recording head moves to the home position adjacent to the recording area at a predetermined interval not only when the recording is completed or when the ejection is recovered, but also while the recording head moves the recording area for recording. However, wiping is also performed with this movement.

  FIG. 12 is a diagram illustrating an example of an ink cartridge 45 that stores ink supplied to the recording head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, in which supply ink is stored, and a rubber plug 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the recording head. An ink absorber 44 receives waste ink.

  The ink of the present invention is not limited to one in which the recording head and the ink cartridge are separated, and as shown in FIG. 13, it can also be suitably used for an ink jet recording apparatus in which they are integrated. In FIG. 13, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the recording head portion in which the ink in the ink absorber has a plurality of ejection openings. 71 is ejected as ink droplets. Alternatively, a structure in which the ink container is an ink bag with a spring or the like inside without using an ink absorber may be used. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 11, and is detachable from the carriage 66.

  The ink of the present invention can be preferably used not only in the ink jet recording type recording apparatus described above but also in an ink jet recording apparatus having a recording head using mechanical energy for ink ejection. Next, an ink jet recording apparatus using mechanical energy will be described. The apparatus includes a nozzle forming substrate having a plurality of nozzles, a pressure generating element composed of a piezoelectric material and a conductive material, ink filling the periphery of the pressure generating element, and displacing the pressure generating element by an applied voltage to drop ink droplets. It is characterized by having a recording head that discharges from the discharge port. FIG. 14 is a schematic diagram illustrating an example of the configuration of the recording head. The recording head includes an ink flow path 80 communicating with an ink chamber, an orifice plate 81, a vibration plate 82 that applies pressure to ink, a piezoelectric element 83 that is bonded to the vibration plate 82 and is displaced by an electric signal, the orifice plate 81, and the vibration plate. It is comprised with the board | substrate 84 which supports and fixes 82 etc. In this recording method, the distortion stress generated by applying a pulsed voltage to the piezoelectric element 83 deforms the vibration plate joined to the piezoelectric element 83 and pressurizes the ink in the ink flow path 80, so that the orifice Ink droplets are ejected from the ejection port 85 of the plate 81. Such a recording head can be used by being incorporated in an ink jet recording apparatus in the same manner as the recording head shown in FIG.

[image]
The image of the present invention is an image formed on a recording medium by ejecting ink by an ink jet method, and the ink is the ink of the present invention described above.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Reference Examples. The present invention is not limited in any way by the following examples as long as the gist thereof is not exceeded. In the following description, unless otherwise specified, “part” or “%” is based on mass, the unit of hydrogen bond term (δh) is “cal ^0.5 / cm ^1.5 ”, and the acid value The unit of “mgKOH / g”. Moreover, all numerical values of the copolymerization ratio of the resin are mass ratios. The resin hydrogen bond term (δh) calculated from the solubility parameter of the monomer constituting the resin is “resin δh”, and the hydrophobic monomer hydrogen bond term (δh) calculated from the solubility parameter is “hydrophobic”. Δh of the functional monomer ”.

<Preparation of ink>
The inks of Examples, Comparative Examples, and Reference Examples were prepared by the following procedure. The carbon black used for preparing the ink has an average particle diameter of 95 nm. Further, acetylenol EH is a surfactant manufactured by Kawaken Fine Chemical Co., Ltd., and its specific structure is an acetylene glycol ethylene oxide adduct. BC20 is a polyoxyethylene alkyl ether surfactant manufactured by Nippon Surfactant Kogyo. In the following description, “solid content” refers to the content of the resin when the resin is in a salt form. In the preparation of the ink, the resin used for the constituents of the pigment dispersions 1 to 14 is Resin A, the resin used for the constituents of the aqueous resin solutions 1 to 24 is Resin B, and the main characteristics of these resins are shown. 2-9 are shown collectively. Here, all the block copolymers used as the resin A are block copolymers having an ethylene oxide group as a nonionic group, and the ratio based on the total mass of the resin A of the ethylene oxide group constituting the resin A Was described as “ratio of EO groups”. Further, when the resin B contains styrene and n-butyl acrylate as monomers, among the monomers constituting the resin B, the mass ratio of n-butyl acrylate based on styrene is “mass ratio of n-BA / St”. It was described.

[Example 1]
A pigment dispersion 1 in which carbon black was dispersed as described below was obtained. First, 37.5 mass% of a 20.0 mass% resin aqueous solution obtained by neutralizing the block copolymer 1 with 1 equivalent of potassium hydroxide, 15.0 mass% of carbon black, and 47.5 mass% of water were mixed. Next, this mixture was thoroughly dispersed with a paint shaker using glass beads to obtain pigment dispersion 1 (pigment content 15.0 mass%, resin A content 7.5 mass%).
The block copolymer 1 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.398 / 0.422 / 0.180, an acid value of 140, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 1 is 24 mass%.

Moreover, the resin aqueous solution 1 was obtained as follows. 15.0% by mass of resin 1 composed of styrene, ethyl acrylate, and acrylic acid, 1 equivalent of potassium hydroxide is added to the carboxylic acid constituting the acrylic acid, and the balance is made 100.0% by mass with water. After the adjustment, the resin 1 was dissolved by stirring at 80 ° C. Then, it adjusted with water so that content of solid content (resin B) might be 15.0 mass%, and the resin aqueous solution 1 was obtained.
Resin 1 used in this example was styrene / ethyl acrylate / acrylic acid = 0.234 / 0.650 / 0.116, acid value 90, weight average molecular weight 7,000, resin δh = 3.2, hydrophobic It is a thing of (delta) h = 2.9 of a property monomer.

The following components including Pigment Dispersion Liquid 1 and Resin Aqueous Solution 1 obtained above were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 1 16.7% by mass
-Resin aqueous solution 1 16.7% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 50.6% by mass

  The following tests were conducted on the ink obtained above. The ink was centrifuged (20,000 rpm, 2 hours) to separate the color material, the sediment was collected, and the sediment was redispersed in water to obtain a dispersion containing the pigment. To the dispersion, an aqueous hydrochloric acid solution was added until the pH became 2 or less, and aggregates were collected. The aggregate was subjected to Soxhlet extraction with tetrahydrofuran (THF), and THF was distilled off to obtain a resin component. The obtained resin component was subjected to NMR measurement. As a result, more styrene-acrylic acid block copolymers having ethylene oxide groups as nonionic groups were detected as compared with resins containing ethyl acrylate and acrylic acid. Therefore, the ink contains two types of resins, but the styrene-acrylic acid block copolymer (resin A) having an ethylene oxide group used as a constituent of the pigment dispersion is mainly used as the pigment. It was confirmed that it was in an adsorbed state.

  The block copolymer 1 contained in the pigment dispersion 1 used in Example 1 was synthesized by the living radical polymerization method as follows. First, methanol is sufficiently degassed to remove moisture, and then cooled with liquid nitrogen. To this, styrene and sodium are added in this order, and then methoxytriethylene glycol methacrylate and acrylic acid are added in that order to block. Copolymer 1 was obtained.

  Further, the resin 1 contained in the aqueous resin solution 1 used in Example 1 was prepared by dropping a mixed solution of styrene / ethyl acrylate / acrylic acid / polymerization initiator (azobisbutyronitrile) into toluene and refluxing temperature. Was synthesized by polymerization.

[Example 2]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 2 containing the resin 2 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 2 used in this example was styrene / benzyl methacrylate / acrylic acid = 0.114 / 0.770 / 0.116, acid value 90, weight average molecular weight 7,000, resin δh = 3.1, hydrophobic Δh of the functional monomer is 2.8.

[Example 3]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 3 containing the resin 3 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 3 used in this example is styrene / ethyl acrylate / acrylic acid = 0.279 / 0.528 / 0.193, acid value 150, weight average molecular weight 7,000, resin δh = 3.2, hydrophobic It is a thing of (delta) h = 2.6 of a property monomer.

[Example 4]
Instead of the block copolymer 1 contained in the pigment dispersion 1 used in Example 1, instead of using the pigment dispersion 2 containing the block copolymer 2, the same as in Example 1, An ink was prepared.
The block copolymer 2 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.347 / 0.422 / 0.231, an acid value of 180, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 2 is 24 mass%.

[Example 5]
Instead of the block copolymer 1 contained in the pigment dispersion 1 used in Example 1, a pigment dispersion 3 containing a block copolymer 3 was used in the same manner as in Example 1, An ink was prepared.
The block copolymer 3 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.424 / 0.422 / 0.154, an acid value of 120, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 3 is 24 mass%.

[Example 6]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 4 containing the resin 4 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 4 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.160 / 0.710 / 0.130, acid value 101, weight average molecular weight 7,000, resin δh = 3.2. The hydrophobic monomer δh = 2.8. In addition, the n-BA / St mass ratio in Polymer 4 is 4.44.

[Example 7]
Instead of the block copolymer 1 contained in the pigment dispersion 1 used in Example 1, a pigment dispersion 4 containing a block copolymer 4 was used.
The block copolymer 4 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.645 / 0.175 / 0.180, an acid value of 140, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 4 is 10 mass%.

Moreover, it replaced with the resin 1 contained in the resin aqueous solution 1 used in Example 1, and used the resin aqueous solution 5 containing the resin 5. FIG.
Resin 5 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.655 / 0.184 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.6. The hydrophobic monomer δh = 0.8. In addition, the n-BA / St mass ratio in Polymer 5 is 0.28.

  Then, an ink was prepared in the same manner as in Example 1 except that the pigment dispersion 4 and the resin aqueous solution 5 obtained above were used.

[Example 8]
Example except that the pigment dispersion 5 containing the block copolymer 5 was used instead of the pigment dispersion 4 containing the block copolymer 4 used for the preparation of the ink of Example 7. Ink was prepared in the same manner as in Example 7.
The block copolymer 5 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.120 / 0.700 / 0.180, an acid value of 140, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 5 is 40 mass%.

[Example 9]
Example except that the pigment dispersion liquid 6 containing the block copolymer 6 was used instead of the pigment dispersion liquid 4 containing the block copolymer 4 used for the preparation of the ink of Example 7. Ink was prepared in the same manner as in Example 7.
The block copolymer 6 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.680 / 0.140 / 0.180, an acid value of 140, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 6 is 8 mass%.

[Example 10]
Example except that the pigment dispersion liquid 7 containing the block copolymer 7 was used instead of the pigment dispersion liquid 4 containing the block copolymer 4 used for the preparation of the ink of Example 7. Ink was prepared in the same manner as in Example 7.
The block copolymer 7 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.032 / 0.788 / 0.180, an acid value of 140, and a weight average molecular weight of 4,000. . Moreover, the ratio of EO group in the block copolymer 7 is 45 mass%.

[Example 11]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 5 containing the resin 5 used in Example 7 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1. Was prepared.

[Example 12]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 6 containing the resin 6 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 6 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.630 / 0.177 / 0.193, acid value 150, weight average molecular weight 6,000, resin δh = 1.7. The hydrophobic monomer δh = 0.8. In addition, the n-BA / St mass ratio in Polymer 6 is 0.28.

[Example 13]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 7 containing the resin 7 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 7 used in this example was styrene / n-butyl acrylate / acrylic acid = 0.661 / 0.193 / 0.116, acid value 90, weight average molecular weight 7,000, resin δh = 1.3. The hydrophobic monomer δh = 0.8. In addition, the n-BA / St mass ratio in Polymer 7 is 0.28.

[Example 14]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 8 containing the resin 8 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 8 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.630 / 0.177 / 0.193, acid value 150, weight average molecular weight 9,000, resin δh = 1.7. The hydrophobic monomer δh = 0.8. In addition, the n-BA / St mass ratio in Polymer 8 is 0.28.

[Example 15]
A pigment dispersion 1-2 in which carbon black was dispersed as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 51.0% by mass of a 20.0% by mass resin aqueous solution, 15.0% by mass carbon black, and 34.0 water. The mass% was mixed. Next, using glass beads, the mixture was well dispersed with a paint shaker to obtain pigment dispersion 1-2 (pigment content 15.0 mass%, resin A content 10.2 mass%). It was.

The following components including the pigment dispersion 1-2 obtained above and the resin aqueous solution 5 used in Example 7 were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 1-2 1-2% by mass
・ Resin aqueous solution 5 13.7% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 53.6% by mass

[Example 16]
A pigment dispersion 1-3 in which carbon black was dispersed as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 45.0% by mass of a 20.0% by mass resin aqueous solution, 15.0% by mass carbon black, and 40.0% water. The mass% was mixed. Next, this mixture is well dispersed with a paint shaker using glass beads to obtain pigment dispersion 1-3 (pigment content 15.0 mass%, resin A content 9.0 mass%). It was.

The following components including the pigment dispersion 1-3 obtained above and the resin aqueous solution 5 used in Example 7 were mixed well, and then further filtered to prepare an ink.
-Pigment dispersion 1-3 16.7% by mass
-Resin aqueous solution 5 15.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 52.3 mass%

[Example 17]
A pigment dispersion 1-4 obtained by dispersing carbon black as described below was obtained. First, 56.1% by mass of a 20.0% by mass aqueous resin solution obtained by neutralizing the block copolymer 1 used in Example 1 with 1 equivalent of potassium hydroxide, 15.0% by mass of carbon black, and 28. 9% by mass was mixed. Next, using glass beads, the mixture was well dispersed with a paint shaker to obtain a pigment dispersion 1-4 (pigment content 15.0 mass%, resin A content 11.2 mass%). It was.

The following components including the pigment dispersion 1-4 obtained above and the aqueous resin solution 5 used in Example 7 were mixed well, and then further filtered to prepare an ink.
-Pigment dispersion 1-4 16.7% by mass
-Resin aqueous solution 5 12.4% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 54.9% by mass

[Example 18]
A pigment dispersion 1-5 obtained by dispersing carbon black as described below was obtained. First, 50.0% by mass of a 20.0% by mass resin aqueous solution obtained by neutralizing the block copolymer 1 used in Example 1 with 1 equivalent of potassium hydroxide, 15.0% by mass of carbon black, and 25.9% of water. The mass% was mixed. Next, using glass beads, this mixture is well dispersed with a paint shaker to obtain pigment dispersion 1-5 (pigment content 15.0 mass%, resin A content 11.8 mass%). It was.

The following components including the pigment dispersion 1-5 obtained above and the aqueous resin solution 5 used in Example 7 were mixed well, and then further filtered to prepare an ink.
Pigment dispersion 1-5 16.7% by mass
-Resin aqueous solution 5 11.9% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 55.4% by mass

[Example 19]
A pigment dispersion 1-6 obtained by dispersing carbon black as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 30.0% by mass of a 20.0% by mass resin aqueous solution, 15.0% by mass carbon black, and 49.0% water. The mass% was mixed. Next, using glass beads, the mixture was well dispersed with a paint shaker to obtain a pigment dispersion 1-6 (pigment content 15.0 mass%, resin A content 7.2 mass%). It was.

The following components including the pigment dispersion 1-6 obtained above and the resin aqueous solution 5 used in Example 7 were mixed well, and then further filtered to prepare an ink.
Pigment dispersion 1-6 16.7% by mass
-Resin aqueous solution 5 12.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 55.3 mass%

[Example 20]
A pigment dispersion 1-7 obtained by dispersing carbon black as described below was obtained. First, 33.0% by mass of a 20.0% by mass aqueous resin solution obtained by neutralizing the block copolymer 1 used in Example 1 with 1 equivalent of potassium hydroxide, 15.0% by mass of carbon black, and 52.0% of water. The mass% was mixed. Next, using glass beads, this mixture is well dispersed with a paint shaker to obtain pigment dispersion 1-7 (pigment content 15.0 mass%, resin A content 6.6 mass%). It was.

The following components including Pigment Dispersion Liquid 1-7 obtained above and Resin Aqueous Solution 5 used in Example 7 were mixed well and then filtered to prepare an ink.
Pigment dispersion 1-7 16.7% by mass
-Resin aqueous solution 5 11.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 56.3 mass%

[Example 21]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 9 containing the resin 9 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 9 used in this example was styrene / n-butyl acrylate / acrylic acid = 0.630 / 0.177 / 0.193, acid value 150, weight average molecular weight 5,000, and resin δh = 1.7. The hydrophobic monomer δh = 0.8. In addition, the n-BA / St mass ratio in Resin 9 is 0.28.

[Example 22]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 10 containing the resin 10 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 10 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.630 / 0.177 / 0.193, acid value 150, weight average molecular weight 10,000, resin δh = 1.7. The hydrophobic monomer δh = 0.8. Moreover, the mass ratio of n-BA / St in the resin 10 is 0.28.

[Example 23]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 11 containing the resin 11 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 11 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.663 / 0.076 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.2. The hydrophobic monomer δh = 0.3. Further, the mass ratio of n-BA / St in the resin 11 is 0.10.

[Example 24]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 12 containing the resin 12 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 12 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.559 / 0.280 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.9. The hydrophobic monomer δh = 1.1. Moreover, the mass ratio of n-BA / St in the resin 12 is 0.50.

[Example 25]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 13 containing the resin 13 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 13 used in this example was styrene / n-butyl acrylate / acrylic acid = 0.671 / 0.168 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.5. The hydrophobic monomer δh = 0.7. Moreover, the mass ratio of n-BA / St in the resin 13 is 0.25.

[Example 26]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 14 containing the resin 14 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 14 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.622 / 0.217 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.7. The hydrophobic monomer δh = 0.9. Moreover, the mass ratio of n-BA / St in the resin 14 is 0.35.

[Example 27]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 15 containing the resin 15 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 15 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.777 / 0.062 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.1. The hydrophobic monomer δh = 0.3. Moreover, the mass ratio of n-BA / St in the resin 15 is 0.08.

[Example 28]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 16 containing the resin 16 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 16 used in this example was styrene / n-butyl acrylate / acrylic acid = 0.546 / 0.293 / 0.161, acid value 125, weight average molecular weight 7,000, resin δh = 1.9. The hydrophobic monomer δh = 1.2. Further, the mass ratio of n-BA / St in the resin 16 is 0.54.

[Example 29]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 17 containing the resin 17 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 17 used in this example has styrene / acrylic acid = 0.825 / 0.175, acid value 136, weight average molecular weight 7,000, resin δh = 1.0, hydrophobic monomer δh = 0. 0.

[Example 30]
The following components including the pigment dispersion 1 used in Example 1 and the aqueous resin solution 12 used in Example 24 were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 1 8.0% by mass
-Resin aqueous solution 12 20.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 56.0% by mass

[Example 31]
A pigment dispersion 1-8 obtained by dispersing carbon black as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 15.0% by mass of a 20.0% by mass resin aqueous solution, 15.0% by mass carbon black, and 70.0% water. The mass% was mixed. Next, this mixture is well dispersed with a paint shaker using glass beads to obtain a pigment dispersion 1-8 (pigment content 15.0 mass%, resin A content 3.0 mass%). It was.

The following components including the pigment dispersion 1-8 obtained above and the aqueous resin solution 12 used in Example 24 were mixed well, and then filtered to prepare an ink.
Pigment dispersion 1-8 8.0% by mass
-Resin aqueous solution 12 20.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 56.0% by mass

[Example 32]
A pigment dispersion 1-9 obtained by dispersing carbon black as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 50.0% by mass of a 20.0% by mass aqueous resin solution, 5.0% by mass of carbon black, and 45.0% of water. The mass% was mixed. Next, using glass beads, the mixture is well dispersed with a paint shaker to obtain pigment dispersion 1-9 (pigment content 5.0 mass%, resin A content 10.0 mass%). It was.

The following components including the pigment dispersion 1-9 obtained above and the aqueous resin solution 12 used in Example 24 were mixed well, and then filtered to prepare an ink.
Pigment dispersion 1-9 24.0% by mass
-Resin aqueous solution 12 20.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 40.0% by mass

[Example 33]
A pigment dispersion 1-10 obtained by dispersing carbon black as described below was obtained. First, 13.8% by mass of a 20.0% by mass aqueous resin solution obtained by neutralizing the block copolymer 1 used in Example 1 with 1 equivalent of potassium hydroxide, 15.0% by mass of carbon black, and 71.2% of water. The mass% was mixed. Next, using glass beads, this mixture is well dispersed with a paint shaker to obtain pigment dispersion 1-10 (pigment content 15.0 mass%, resin A content 2.8 mass%). It was.

The following components including the pigment dispersion 1-10 obtained above and the aqueous resin solution 12 used in Example 24 were mixed well, and then filtered to prepare an ink.
Pigment dispersion 1-10 8.0% by mass
-Resin aqueous solution 12 20.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 56.0% by mass

[Example 34]
A pigment dispersion 1-11 obtained by dispersing carbon black as described below was obtained. First, the block copolymer 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 54.2% by mass of a 20.0% by mass resin aqueous solution, 5.0% by mass carbon black, and 40.8% water. The mass% was mixed. Next, using glass beads, the mixture was well dispersed with a paint shaker to obtain pigment dispersion 1-11 (pigment content 5.0 mass%, resin A content 10.8 mass%). It was.

The following components including the pigment dispersion 1-11 obtained above and the resin aqueous solution 12 used in Example 24 were thoroughly mixed, and then further filtered to prepare an ink.
Pigment dispersion 1-11 24.0% by mass
-Resin aqueous solution 12 20.0% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 40.0% by mass

[Example 35]
Resin aqueous solution 12 used in Example 24 was changed from 20.0% by mass to 26.7% by mass, and water was changed from 56.0% by mass to 49.3% by mass in the same manner as in Example 30. Ink was prepared.

[Example 36]
Resin aqueous solution 12 used in Example 24 was changed from 20.0% by mass to 33.3% by mass, and water was changed from 56.0% by mass to 42.7% by mass in the same manner as in Example 30. Ink was prepared.

[Example 37]
Resin aqueous solution 12 used in Example 24 was changed from 20.0% by mass to 19.3% by mass, and water was changed from 56.0% by mass to 56.7% by mass in the same manner as in Example 30. Ink was prepared.

[Example 38]
Resin aqueous solution 12 used in Example 24 was changed from 20.0% by mass to 40.0% by mass, and water was changed from 56.0% by mass to 36.0% by mass in the same manner as in Example 30. Ink was prepared.

[Example 39]
Except that the aqueous resin solution 12 used in Example 24 was changed from 20.0% by mass to 32.0% by mass and from 56.0% by mass to 44.0% by mass, in the same manner as in Example 31. Ink was prepared.

[Example 40]
Except that the aqueous resin solution 12 used in Example 24 was changed from 20.0% by mass to 33.3% by mass and water was changed from 56.0% by mass to 42.7% by mass, in the same manner as in Example 31. Ink was prepared.

[Example 41]
A pigment dispersion 8 obtained by dispersing carbon black as described below was obtained. First, 37.5% by mass of a 20.0% by mass resin aqueous solution obtained by neutralizing the block copolymer 8 with 1 equivalent of potassium hydroxide, 15.0% by mass of carbon black, and 47.5% by mass of water were mixed. Next, this mixture was thoroughly dispersed with a paint shaker using glass beads to obtain a pigment dispersion 8 (pigment content 15.0 mass%, resin A content 7.5 mass%).
The block copolymer 8 used in this example has a styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.398 / 0.422 / 0.180, an acid value of 140, and a weight average molecular weight of 3,000. . Moreover, the ratio of the EO group in the block copolymer 8 is 24 mass%.

The following components including the pigment dispersion 8 obtained above and the resin aqueous solution 5 used in Example 7 were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 8 16.7% by mass
-Resin aqueous solution 5 16.7% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 50.6% by mass

[Example 42]
Instead of the block copolymer 8 contained in the pigment dispersion 8 used in Example 41, the same procedure as in Example 41 was used except that the pigment dispersion 9 containing the block copolymer 9 was used. An ink was prepared.
The block copolymer 9 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.398 / 0.422 / 0.180, an acid value of 140, and a weight average molecular weight of 6,000. . Moreover, the ratio of the EO group in the block copolymer 9 is 24 mass%.

[Example 43]
Instead of the block copolymer 8 contained in the pigment dispersion 8 used in Example 41, the same procedure as in Example 41 was used except that the pigment dispersion 10 containing the block copolymer 10 was used. An ink was prepared.
The block copolymer 10 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.398 / 0.422 / 0.180, an acid value of 140, and a weight average molecular weight of 2,000. . Moreover, the ratio of the EO group in the block copolymer 10 is 24 mass%.

[Example 44]
Instead of the block copolymer 8 contained in the pigment dispersion 8 used in Example 41, the same procedure as in Example 41 was used except that the pigment dispersion 11 containing the block copolymer 11 was used. An ink was prepared.
The block copolymer 11 used in this example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.398 / 0.422 / 0.180, an acid value of 140, and a weight average molecular weight of 7,000. . Moreover, the ratio of the EO group in the block copolymer 11 is 24 mass%.

[Example 45]
An ink was prepared in the same manner as in Example 44 except that the resin aqueous solution 18 containing the resin 18 was used instead of the resin 5 contained in the resin aqueous solution 5 used in Example 44.
Resin 18 used in this example is styrene / n-butyl acrylate / acrylic acid = 0.655 / 0.184 / 0.161, acid value 125, weight average molecular weight 6,000, resin δh = 1.6. The hydrophobic monomer δh = 0.8. Moreover, the mass ratio of n-BA / St in the resin 18 is 0.28.

[ Reference Example 46]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 19 containing the resin 19 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 19 used in this example was styrene / n-butyl acrylate / acrylic acid = 0.
687 / 0.200 / 0.113, acid number 88, weight average molecular weight 7,000, resin δh =
1.3, δh = 0.8 of the hydrophobic monomer. In addition, n-BA in resin 19
The mass ratio of / St is 0.29.

[Comparative Example 1]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 20 containing the resin 20 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 20 used in this comparative example is styrene / ethyl acrylate / acrylic acid = 0.220 / 0.640 / 0.140, acid value 109, weight average molecular weight 7,000, resin δh = 3.3, hydrophobic It is a thing of (delta) h = 2.9 of a property monomer.

[Comparative Example 2]
Instead of the block copolymer 1 contained in the pigment dispersion 1 used in Example 1, instead of using the pigment dispersion 12 containing the block copolymer 12, the same as in Example 1, An ink was prepared.
The block copolymer 12 used in this comparative example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.430 / 0.422 / 0.148, an acid value of 115, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 12 is 24 mass%.

[Comparative Example 3]
Instead of the block copolymer 1 contained in the pigment dispersion 1 used in Example 1, a pigment dispersion 13 containing a block copolymer 13 was used in the same manner as in Example 1, An ink was prepared.
The block copolymer 13 used in this comparative example has styrene / methoxytriethylene glycol methacrylate / acrylic acid = 0.340 / 0.422 / 0.238, an acid value of 185, and a weight average molecular weight of 4,000. . Moreover, the ratio of the EO group in the block copolymer 13 is 24 mass%.

[Comparative Example 4]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 21 containing the resin 21 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 21 used in this comparative example is styrene / ethyl acrylate / acrylic acid = 0.833 / 0.050 / 0.116, acid value 90, weight average molecular weight 7,000, resin δh = 0.9, hydrophobic Of the reactive monomer, δh = 0.2.

[Comparative Example 5]
A pigment dispersion 14 obtained by dispersing carbon black as described below was obtained. First, the resin 1 used in Example 1 was neutralized with 1 equivalent of potassium hydroxide, 37.5 mass% of a 20.0 mass% resin aqueous solution, 15.0 mass% of carbon black, and 47.5 mass% of water. Mixed. Next, using glass beads, this mixture was well dispersed with a paint shaker to obtain a pigment dispersion 14 (pigment content 15.0 mass%, resin content 7.5 mass%).

  Moreover, the resin aqueous solution 1-2 was obtained as follows. The resin 1 used in Example 1 was 20.0% by mass, 1 equivalent of potassium hydroxide was added to the carboxylic acid contained in the resin 1, and the remainder was adjusted to 100.0% by mass with water. And the resin 1 was dissolved. Then, it adjusted with water so that content of solid content (resin B) might be 20.0 mass%, and resin aqueous solution 1-2 was obtained.

The following components including the pigment dispersion 14 obtained above and the resin aqueous solution 1-2 obtained above were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 14 16.7% by mass
-Resin aqueous solution 1-2 12.5% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 54.8% by mass

[Comparative Example 6]
A resin aqueous solution 22 was obtained as follows. 20.0% by mass of the block copolymer 1 used in Example 1, 1 equivalent of potassium hydroxide is added to the carboxylic acid contained in the block copolymer 1, and the remainder is made 100.0% by mass with water. After the adjustment, the block copolymer 1 was dissolved by stirring at 80 ° C. Then, it adjusted with water so that content of solid content (resin) might be 20.0 mass%, and resin aqueous solution 22 was obtained.

The following components including Pigment Dispersion Liquid 1 and Resin Aqueous Solution 22 used in Example 1 were mixed well, and further filtered to prepare an ink.
-Pigment dispersion 1 16.7% by mass
・ Resin aqueous solution 22 12.5% by mass
・ Glycerin 5.0% by mass
・ 9.0% by mass of ethylene urea
・ BC20 1.5% by mass
・ Acetylenol EH 0.5% by mass
・ Water 54.8% by mass

[Reference Example 1]
An ink was prepared in the same manner as in Example 1, except that the resin aqueous solution 23 containing the resin 23 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 23 used in this reference example is styrene / benzyl methacrylate / acrylic acid = 0.166 / 0.635 / 0.199, acid value 155, weight average molecular weight 7,000, resin δh = 3.2, hydrophobic Of the reactive monomer is δh = 2.5.

[Reference Example 2]
An ink was prepared in the same manner as in Example 1 except that the resin aqueous solution 24 containing the resin 24 was used instead of the resin 1 contained in the resin aqueous solution 1 used in Example 1.
Resin 24 used in this reference example is styrene / ethyl acrylate / acrylic acid = 0.235 / 0.652 / 0.113, acid value 88, weight average molecular weight 7,000, resin δh = 3.2, hydrophobic It is a thing of (delta) h = 2.9 of a property monomer.

<Hydrogen bond term (δh) of resin calculated from solubility parameter of monomer constituting resin>
The hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin was determined as follows. First, the hydrogen bond term (δh) of each monomer constituting the resin is calculated from the solubility parameter specific to each monomer constituting the resin. Then, a value obtained by multiplying the hydrogen bond term (δh) of each monomer constituting the resin by the composition (mass) ratio (composition ratio with the sum being 1) of each monomer constituting the resin is obtained. Next, by adding these values, the hydrogen bond term of the resin calculated from the solubility parameter of the monomer constituting the resin can be obtained. Table 1 shows the value of the hydrogen bond term (δh) of the monomer calculated from the solubility parameter specific to the monomer constituting the resin for each resin used in the preparation of the pigment dispersion.

Below, how to obtain | require the hydrogen bond term of resin calculated from the solubility parameter of the monomer which comprises resin obtained using the value of Table 1 is shown concretely. Here, resin 1 which is a copolymer of styrene-ethyl acrylate-acrylic acid (composition (mass) ratio = 0.234: 0.650: 0.116) used in Example 1 will be described as an example. . From Table 1 below, the hydrogen bond term (unit: cal ^0.5 / cm ^1.5 ) of the monomer calculated from the solubility parameter of styrene, ethyl acrylate, and acrylic acid, which are monomers constituting the resin 1, is 0.00. 3.90 and 5.81. Therefore, the hydrogen bond term (δh) of the resin 1 calculated from the solubility parameter of the monomer constituting the resin 1 can be obtained from the monomer composition as follows.
Resin hydrogen bond term (δh) calculated from solubility parameter of monomer constituting resin 1
= 0.00 × 0.234 + 3.90 × 0.650 + 5.81 × 0.116
= 3.2 (cal ^0.5 / cm ^1.5 )

<Summary of physical properties of resin used in each ink and characteristics of each ink>
Tables 2 to 11 show values of physical properties of Resin A and Resin B, pigments in the ink, contents of Resin A and Resin B, and the like used in Examples, Comparative Examples, and Reference Examples.

（*1）樹脂を構成するモノマーの溶解度パラメーターより算出される樹脂の水素結合項（δｈ）［ｃａｌ^0.5／ｃｍ^1.5］
（*2）疎水性モノマーの水素結合項（δｈ）［ｃａｌ^0.5／ｃｍ^1.5］
（*3）樹脂における、スチレンを基準としたｎ−ブチルアクリレートの質量比率

(* 1) Resin hydrogen bond term (δh) [cal ^0.5 / cm ^1.5 ] calculated from the solubility parameter of the monomer constituting the resin
(* 2) Hydrogen bond term of hydrophobic monomer (δh) [cal ^0.5 / cm ^1.5 ]
(* 3) Mass ratio of n-butyl acrylate based on styrene in the resin

（*1）樹脂を構成するモノマーの溶解度パラメーターより算出される樹脂の水素結合項（δｈ）［ｃａｌ^0.5／ｃｍ^1.5］
（*2）疎水性モノマーの水素結合項（δｈ）［ｃａｌ^0.5／ｃｍ^1.5］
（*3）樹脂における、スチレンを基準としたｎ−ブチルアクリレートの質量比率

(* 1) Resin hydrogen bond term (δh) [cal ^0.5 / cm ^1.5 ] calculated from the solubility parameter of the monomer constituting the resin
(* 2) Hydrogen bond term of hydrophobic monomer (δh) [cal ^0.5 / cm ^1.5 ]
(* 3) Mass ratio of n-butyl acrylate based on styrene in the resin

<Evaluation>
(Abrasion resistance)
Each ink obtained above was mounted on an ink jet recording apparatus (trade name: BJF900; manufactured by Canon Inc.) to form a 100% duty image on UF120 (manufactured by Canon Inc.). The obtained recorded matter was allowed to stand at room temperature for 1 day, and then the image was scratched with a nail so that the non-recorded portion of the recording medium was not damaged. The recorded matter was visually confirmed to evaluate scratch resistance. The evaluation criteria for scratch resistance are as follows. The results are summarized in Table 12 and Table 13.
5: The white part of the ground was not recognized.
4: Slight white background was observed.
3: About half of the scratched part became white.
2: The scratched part was almost white.
1: The scratched part was all white.

(Storage stability)
Each ink obtained above was put in a Teflon (registered trademark) container and stored at a temperature of 60 ° C. for one month. The particle size of the ink before and after storage was measured with a particle size measuring device UPA (manufactured by Microtrac), and storage stability was evaluated. The evaluation criteria for storage stability are as follows. The results are summarized in Table 12 and Table 13.
5: The increase rate of the particle size after storage was less than 5% compared to the particle size before storage.
4: The increase rate of the particle size after storage was 5% or more and less than 10% compared to the particle size before storage.
3: The increase rate of the particle size after storage was 10% or more and less than 15% compared to the particle size before storage.
2: The increase rate of the particle size after storage was 15% or more and less than 20% compared to the particle size before storage.
1: The increase rate of the particle size after storage was 20% or more as compared with the particle size before storage, or aggregates were observed after storage.

Resins hydrogen bond of the resin obtained by the solubility parameters of monomers constituting the polymer is more than 3.2cal ^0.5 / cm ^1.5 is a schematic view showing a state dissolved in the aqueous medium. 4 is a schematic diagram showing how a resin having a hydrogen bond term of more than 3.2 cal ^0.5 / cm ^1.5 calculated from the solubility parameter of the monomer constituting the resin penetrates into the recording medium D. FIG. Resin hydrogen bond of the resin obtained by the solubility parameters of monomers constituting the polymer is 3.2cal ^0.5 / cm ^1.5 or less is a schematic view showing a state dissolved in the aqueous medium. 4 is a schematic diagram showing a state in which a resin having a hydrogen bond term of 3.2 cal ^0.5 / cm ^1.5 or less calculated from a solubility parameter of monomers constituting the resin aggregates on a recording medium D. FIG. It is a schematic diagram which shows the dispersion state of a water-insoluble color material (pigment). It is a schematic diagram which shows the cross section of the image formed with the ink with small content of a water-insoluble coloring material. It is a schematic diagram which shows the cross section of the image formed with the ink with large content of a water-insoluble coloring material. FIG. 2 is a longitudinal sectional view of a recording head. It is a vertical and horizontal view of a recording head. FIG. 9 is a perspective view of a recording head in which the recording head shown in FIG. It is a perspective view which shows an example of an inkjet recording device. It is a longitudinal cross-sectional view of an ink cartridge. It is a perspective view which shows an example of a recording unit. FIG. 3 is a schematic diagram illustrating an example of a configuration of a recording head.

Explanation of symbols

A: Water molecule B: Hydrophilic part C: Hydrophobic part D: Recording medium E: Water-insoluble colorant (pigment)
F: resin film 13: recording head 14: nozzle 15: heating element substrate 16: protective layer 17-1, 17-2: electrode 18: heating resistor layer 19: heat storage layer 20: substrate 21: ink 22: discharge port 23: meniscus 24: ink droplet 25: recording medium 26: multi-nozzle 27: glass plate 28: recording head 40: ink bag (ink container)
42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Ejection recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Recording head 72: Atmospheric communication port 80: Ink channel 81: Orifice plate 82: Vibration plate 83: Piezoelectric element 84: Substrate 85: Ejection port

Claims (14)

An aqueous inkjet ink containing at least a water-insoluble colorant and a plurality of resins,
The plurality of resins include a resin A and a resin B,
More resin A is detected than resin B in the sediment when the aqueous ink is centrifuged at 20,000 rpm for 2 hours,
The resin A is a block copolymer having an acid value of 120 mgKOH / g or more and 180 mgKOH / g or less and having an ethylene oxide group as a nonionic group,
The resin B has an acid value of 90 mgKOH / g or more and 150 mgKOH / g or less, and the hydrogen bond term (δh) of the resin calculated from the solubility parameter of the monomer constituting the resin is 1.0 cal ^0.5 / cm ^1.5 or more. A water-based ink characterized in that it is 3.2 cal ^0.5 / cm ^1.5 or less. Wherein and hydrophobic monomer are used as a component of the resin B, the solubility hydrogen bond hydrophobic monomer calculated from the parameter (.delta.h) is according to claim 1 is 2.8cal ^0.5 / cm ^1.5 or less Water based ink. 3. The water-based ink according to claim 1, wherein the weight average molecular weight of the resin B is larger than the weight average molecular weight of the resin A, and the weight average molecular weight of the resin B is 5,000 or more. The total content of the resin A based on the total mass of the ink (mass%) and the content of the resin B (mass%) is the content of the water-insoluble colorant based on the total mass of the ink ( The water-based ink according to any one of claims 1 to 3 , wherein the water-based ink is 1.20 times or more of (% by mass). The ethylene oxide group constituting the polymer A, the ratio relative to the resin A total mass, the aqueous ink according to any one of claims 1 to 4 or less 10 wt% to 40 wt%. Monomers constituting the resin B is an aqueous ink according to any one of claims 1 to 5 including a n- butyl acrylate. The aqueous ink according to claim 6 , wherein the monomer constituting the resin B further contains styrene. 8. The water-based ink according to claim 7 , wherein among the monomers constituting the resin B, a mass ratio of n-butyl acrylate based on styrene is 0.10 or more and 0.50 or less. The content (% by mass) of the resin B based on the total mass of the ink is 1.0 times or more with respect to the content (% by mass) of the resin A based on the total mass of the ink. 9. The water-based ink according to any one of items 8 to 8 . An ink jet recording method for recording on a recording medium by discharging ink by an ink jet method,
An ink jet recording method, wherein the ink is the water-based ink according to any one of claims 1 to 9 . An ink cartridge comprising an ink containing portion for containing ink,
The ink accommodated in the said ink accommodating part is the water-based ink of any one of Claim 1 thru | or 9 , The ink cartridge characterized by the above-mentioned. A recording unit comprising an ink storage portion for storing ink and a recording head for discharging ink,
Recording units ink contained in the ink receiving portion, characterized in that it is a water-based ink according to any one of claims 1 to 9. An ink jet recording apparatus comprising an ink containing portion for containing ink and a recording head for discharging ink,
The ink accommodated in the said ink accommodating part is the water-based ink of any one of Claim 1 thru | or 9 , The inkjet recording device characterized by the above-mentioned. An image formed on a recording medium by ejecting ink by an inkjet method,
An image, wherein the ink is the water-based ink according to any one of claims 1 to 9 .

Images