JP2014012765A - Compound, ink, ink cartridge and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel xanthene-based compound that is useful as a color material of an ink and excellent in optical density and light resistance, and has preferable hue in a magenta region to a red region.SOLUTION: A compound represented by the following general formula (1) (wherein R,R,Rand Reach independently represent an alkyl group; Rand Reach independently represent an alkyl group and the like; R,,R,,Rand Reach independently represent a hydrogen atom and the like; M represents a hydrogen atom and the like; any one of Rto Rrepresents a hydroxy group and the others represent a hydrogen atom) is provided.

Description

  The present invention relates to a novel compound having a xanthene skeleton, an ink containing the compound, an ink cartridge using the ink, and an ink jet recording method.

  A compound having a xanthene skeleton is generally excellent in optical density and light resistance, and has been widely used for dyeing, paints and inks for a long time. In addition, a compound having a xanthene skeleton has excellent production suitability because the number of steps in the synthesis is small as compared with a coloring material having another skeleton. In recent years, the use of color materials has been diversified, and it is desired not only to have excellent image characteristics such as optical density and light resistance, but also to have a preferable hue in the magenta to red region.

  Representative examples of compounds having a xanthene skeleton (coloring material) include C.I. I. Acid Red 289. Patent Document 1 discloses C.I. I. A compound having a structure similar to Acid Red 289 and having good optical density and light resistance is disclosed.

JP 2011-148773 A

  We have described C.I. I. It was confirmed that by using Acid Red 289 and the compound described in Patent Document 1, an image having good optical density and light resistance can be recorded. However, even when these compounds are used, an image having a preferable hue in the magenta to red region cannot be recorded.

  Accordingly, an object of the present invention is to provide a novel xanthene-based compound that is useful as an ink coloring material, has excellent optical density and light resistance, and has a preferable hue in the magenta to red range.

  The above object is achieved by the present invention described below. That is, according to the present invention, a compound represented by the following general formula (1) is provided.

（前記一般式（１）中、Ｒ₁、Ｒ₅、Ｒ₆及びＲ₁₀はそれぞれ独立に、アルキル基を表す。Ｒ₃及びＲ₈はそれぞれ独立に、水素原子、アルキル基、アルコキシ基、又はアリールオキシ基を表す。Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉はそれぞれ独立に、水素原子又は下記一般式（２）で表されるアシルアミノ基を表し、Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉の少なくともひとつは下記一般式（２）で表されるアシルアミノ基である。Ｍは水素原子、アルカリ金属、アンモニウム、又は有機アンモニウムを表す。Ｒ₁₂乃至Ｒ₂₁は、いずれかひとつがヒドロキシ基を表し、残りは水素原子を表す）

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or R ₂ , R ₄ , R ₇ and R ₉ each independently represents a hydrogen atom or an acylamino group represented by the following general formula (2), R ₂ , R ₄ , R ₇ and R _At least one of ₉ is an acylamino group represented by the following general formula (2): M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and any one of R _{12 to} R ₂₁ represents a hydroxy group. And the rest represent hydrogen atoms)

（前記一般式（２）中、Ｒ₁₁はアルキル基、シクロアルキル基、アリール基、アリールアルキル基、アルケニル基、又はヘテロ環基を表し、＊は前記一般式（１）における芳香環との結合部位を表す。）

(In the general formula (2), R ₁₁ represents an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an alkenyl group, or a heterocyclic group, and * represents a bond to an aromatic ring in the general formula (1). Represents the site.)

  According to the present invention, it is possible to provide a novel xanthene-based compound that is useful as an ink coloring material, has excellent optical density and light resistance, and has a preferable hue in the magenta to red region. In addition, according to the present invention, it is possible to provide an ink containing this compound, which is excellent in optical density and light resistance and capable of recording an image having a preferable hue in the magenta to red region. Furthermore, according to the present invention, an ink cartridge using this ink and an ink jet recording method can be provided.

It is sectional drawing which shows typically one Embodiment of the ink cartridge of this invention. FIG. 2 is a diagram schematically illustrating an example of an ink jet recording apparatus used in the ink jet recording method of the present invention, in which (a) is a perspective view of a main part of the ink jet recording apparatus, and (b) is a perspective view of a head cartridge.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. In the present invention, when the compound is a salt, the salt is dissociated into ions in the ink, but is expressed as “contains a salt” for convenience.

<Compound represented by the general formula (1)>
As a result of investigation, the present inventors have determined that C.I. As a compound having an optical density and light resistance equivalent to those of I. Acid Red 289 and having a preferable hue in the red region from magenta, a compound represented by the following general formula (1) was found. The compound represented by the following general formula (1) is a compound having a xanthene skeleton having a hydroxy group introduced therein. The compound of the present invention can be used alone or as a mixture of isomers having different hydroxy group bonding positions. In the present invention, the preferable hue in the magenta to red region means that the hue angle (H °) is 15 or more and 35 or less.

（前記一般式（１）中、Ｒ₁、Ｒ₅、Ｒ₆及びＲ₁₀はそれぞれ独立に、アルキル基を表す。Ｒ₃及びＲ₈はそれぞれ独立に、水素原子、アルキル基、アルコキシ基、又はアリールオキシ基を表す。Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉はそれぞれ独立に、水素原子又は下記一般式（２）で表されるアシルアミノ基を表し、Ｒ₂、Ｒ₄、Ｒ₇及びＲ₉の少なくともひとつは下記一般式（２）で表されるアシルアミノ基である。Ｍは水素原子、アルカリ金属、アンモニウム、又は有機アンモニウムを表す。Ｒ₁₂乃至Ｒ₂₁は、いずれかひとつがヒドロキシ基を表し、残りは水素原子を表す）

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or R ₂ , R ₄ , R ₇ and R ₉ each independently represents a hydrogen atom or an acylamino group represented by the following general formula (2), R ₂ , R ₄ , R ₇ and R _At least one of ₉ is an acylamino group represented by the following general formula (2): M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and any one of R _{12 to} R ₂₁ represents a hydroxy group. And the rest represent hydrogen atoms)

（前記一般式（２）中、Ｒ₁₁はアルキル基、シクロアルキル基、アリール基、アリールアルキル基、アルケニル基、又はヘテロ環基を表し、＊は前記一般式（１）における芳香環との結合部位を表す。）

(In the general formula (2), R ₁₁ represents an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an alkenyl group, or a heterocyclic group, and * represents a bond to an aromatic ring in the general formula (1). Represents the site.)

R ₁ , R ₅ , R ₆ and R ₁₀ in the general formula (1) each independently represent an alkyl group. Examples of the alkyl group include straight-chain and branched-chain alkyl, which may have a substituent. More specifically, straight chain alkyl groups such as methyl, ethyl, n-propyl, and n-butyl groups; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, and tert-butyl groups Can be mentioned. Of these, alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group are preferable from the viewpoint of synthesis. As the substituent, for example, a hydroxy group, an alkoxy group, a cyano group, and a halogen atom are preferable from the viewpoint of synthesis. Examples of the alkyl group having a substituent include a hydroxyethyl group, a methoxyethyl group, a cyanoethyl group, and a trifluoromethyl group. When R ₁ , R ₅ , R ₆ and R ₁₀ have a substituent, it is preferable that all the substituents are the same from the viewpoints of spectral reflection characteristics, hue, and synthesis.

In general formula (1), R ₃ and R ₈ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryloxy group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, and trifluoro. A methyl group, 3-sulfopropyl group, 4-sulfobutyl group, etc. can be mentioned. Examples of the alkoxy group include methoxy group, ethoxy group, isopropoxy group, methoxyethoxy group, hydroxyethoxy group, and 3-carboxypropoxy group. Examples of the aryloxy group include a phenoxy group, a p-methoxyphenoxy group, an o-methoxyphenoxy group, a tolyloxy group, a xylyloxy group, and a naphthoxy group. Any of these alkyl groups, alkoxy groups, and aryloxy groups may have a substituent. Examples of the substituent include an alkyl group, aryl group, arylalkyl group, hydroxy group, carbamoyl group, sulfamoyl group, alkoxy group, cyano group, halogen atom, and ionic group. Examples of the ionic group include cationic groups such as triethylammonium group and trimethylammonium group; anionic groups such as carboxy group, sulfonic acid group, and phosphoric acid group. In the present invention, from the viewpoint of light resistance, it is preferable that R ₃ and R ₈ are each independently a methyl group, an ethyl group, or a propyl group. From the viewpoint of synthesis, when R ₃ and R ₈ have a substituent, it is preferable that all the substituents are the same.

In general formula (1), R ₂ , R ₄ , R ₇ and R ₉ each independently represent a hydrogen atom or an acylamino group represented by general formula (2). Furthermore, at least one of R ₂ , R ₄ , R ₇ and R ₉ is an acylamino group represented by the general formula (2). C. I. As in Acid Red 289, in order for the compound represented by the general formula (1) to have high optical density and high light resistance, at least one of R ₂ , R ₄ , R ₇ and R ₉ is represented by the general formula (2 It is necessary to be an acylamino group represented by In the present invention, from the viewpoint of optical density and light resistance, the number of acylamino groups represented by the general formula (2) in the general formula (1) is preferably 2 to 4. Moreover, when the number of the acylamino groups represented by the general formula (2) in the general formula (1) is plural, it is preferable that all the acylamino groups are the same from the viewpoint of synthesis. Furthermore, from the viewpoint of synthesis, in the general formula (1), combinations of R ₁ and R ₆ , R ₂ and R ₇ , R ₃ and R ₈ , R ₄ and R ₉ , and R ₅ and R ₁₀ are respectively It is preferable that they are the same.

In General Formula (2), R ₁₁ represents an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an alkenyl group, or a heterocyclic group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, and trifluoro. A methyl group, 3-sulfopropyl group, 4-sulfobutyl group, etc. can be mentioned. Examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. Examples of the aryl group include a phenyl group, a p-tolyl group, a p-methoxyphenyl group, an o-chlorophenyl group, and an m- (3-sulfopropylamino) phenyl group. Examples of the arylalkyl group include a benzyl group and a 2-phenethyl group. Examples of the alkenyl group include a vinyl group, 1-propenyl group, 2-propenyl group, 1-methylethenyl group, 1-butenyl group, 2-butenyl group, and 3-butenyl group. Heterocyclic groups include imidazolyl, benzoimidazolyl, pyrazolyl, benzopyrazolyl, triazolyl, thiazolyl, benzothiazolyl, isothiazolyl, benzisothiazolyl, oxazolyl, benzoxazolyl, thiadiazolyl, pyrrolyl Group, benzopyrrolyl group, indolyl group, isoxazolyl group, benzoisoxazolyl group, thienyl group, benzothienyl group, furyl group, benzofuryl group, pyridyl group, quinolyl group, isoquinolyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, cinnolinyl Group, phthalazinyl group, quinazolinyl group, quinoxalinyl group, triazinyl group and the like.

R ₁₁ in the general formula (2) may have a substituent. Examples of the substituent include alkyl group, aryl group, arylalkyl group, alkenyl group, alkoxy group, cyano group, alkylamino group, sulfoalkyl group, carbamoyl group, sulfamoyl group, sulfonylamino group, halogen atom, ionic group, etc. Can be mentioned. Examples of the ionic group include cationic groups such as triethylammonium group and trimethylammonium group; anionic groups such as carboxy group, sulfonic acid group, and phosphoric acid group. In the present invention, R ₁₁ is preferably an alkyl group, a cycloalkyl group, an aryl group, or an arylalkyl group from the viewpoint of optical density. From the viewpoint of synthesis, R ₁₁ is preferably an alkyl group or an aryl group. R ₁₁ is preferably a linear alkyl group or an aryl group substituted with an ionic group in that particularly excellent light resistance can be obtained.

In general formula (1), M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium. Examples of the alkali metal include lithium, sodium, and potassium. As organic ammonium, methyl ammonium, dimethyl ammonium, trimethyl ammonium, tetramethyl ammonium, ethyl ammonium, diethyl ammonium, triethyl ammonium, tetraethyl ammonium, n-propyl ammonium, isopropyl ammonium, diisopropyl ammonium, n-butyl ammonium, tetra n-butyl Ammonium, isobutylammonium, monoethanolammonium, diethanolammonium, triethanolammonium, etc. can be mentioned. In addition, although at least a part of the SO ₃ M group is ion-dissociated in the ink, even if no ion dissociation occurs, it is of course included in the compound of the present invention.

In general formula (1), any one of R _{12 to} R ₂₁ represents a hydroxy group, and the remainder represents a hydrogen atom. Although depending on the synthesis method, the position of the hydrogen atom can be controlled by changing the raw materials used for the synthesis.

  Specific preferred examples of the compound represented by the general formula (1) include exemplified compounds 1 to 19 (free acid type) shown in Table 1. Of course, the compound of the present invention is not limited to the following exemplified compound as long as it is included in the structure of the general formula (1) and its definition. In the present invention, among the exemplary compounds shown in Table 1, exemplary compounds 2 to 4 are preferable, and exemplary compound 4 is more preferable. In Table 1, Me represents methyl, Et represents ethyl, n-Pr represents n-propyl, and i-Pr represents i-propyl.

The compound represented by the general formula (1) can be synthesized by appropriately combining known synthesis methods. An example of a synthesis scheme of the compound represented by the general formula (1) is shown below. In the synthesis scheme shown below, any one of Z _{1 to} Z ₁₀ in the compounds (3) to (6) is a hydroxy group, and the remainder is a hydrogen atom. In the compound (7), any one of Y _{1 to} Y ₁₀ is a chlorine atom, and the remaining is a hydrogen atom. Compound (8) to (10) R ₁ to R ₂₁ in is synonymous with R ₁ through R ₂₁ in general formula (1).

  In the above synthesis scheme, the first condensation step and chlorination step shown in the first stage, the second condensation step shown in the second stage, and the third condensation step shown in the third stage A compound represented by the formula (1) is synthesized.

  In the first condensation step, compound (3), compound (4), and compound (5) are condensed by heating in the presence of concentrated sulfuric acid or the like to obtain compound (6). Furthermore, a compound (7) is obtained by chlorinating a compound (6) using a chlorinating agent. Next, in the second condensation step, compound (7) and compound (8) are heated and condensed in the presence of an organic solvent or a condensing agent to obtain compound (9). Further, in the third condensation step, the compound represented by the general formula (1) can be obtained by heating and condensing the compound (9) and the compound (10).

  The organic solvent used in each condensation step of the above synthesis scheme will be described. In the first condensation step, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol and the like are preferably used alone or in combination. In the second and third condensation steps, for example, ethylene glycol, N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, chlorobenzene, dichlorobenzene, trichlorobenzene, nitrobenzene, etc. It is preferable to use alone or in combination.

The reaction temperature in the first condensation step is preferably 60 ° C. or higher and 100 ° C. or lower, and more preferably 70 ° C. or higher and 90 ° C. or lower. The reaction temperature in the second and third condensation steps is preferably 120 ° C. or higher and 220 ° C. or lower, and more preferably 180 ° C. or lower. When synthesizing a compound in which R _{1 to} R ₅ and R _{6 to} R _{10 in the} general formula (1) are the same group, the compound (8) and the compound (10) in the above synthesis scheme are the same. What is necessary is just to use. Therefore, in this case, the compound represented by the general formula (1) can be obtained by performing a one-step condensation process from the compound (7). The reaction temperature at that time is preferably 120 ° C. or higher and 220 ° C. or lower, and more preferably 180 ° C. or lower. As the condensing agent, for example, magnesium oxide, zinc chloride, aluminum chloride or the like is preferably used.

  The compound (dye) represented by the general formula (1), which is the final product obtained by the above synthesis scheme, is purified after being processed in accordance with a post-treatment method of a normal organic synthesis reaction, whereby an ink coloring material is obtained. It can be used for such applications.

<Ink>
(Color material)
The ink of the present invention is an ink suitable for inkjet use containing a coloring material containing the compound of the present invention represented by the general formula (1) described above. By using the ink of the present invention, an image having excellent optical density and light resistance and having a preferable hue in the magenta to red region can be recorded.

(Other compounds having xanthene skeleton)
The color material contained in the ink of the present invention contains a compound having a xanthene skeleton (excluding the compound represented by the general formula (1)) in addition to the compound represented by the general formula (1). It is preferable to do. That is, it is preferable to use a compound represented by the general formula (1) and a compound having a xanthene skeleton, which is different from the compound represented by the general formula (1), as the coloring material of the ink. The present inventors have found that the light resistance of the recorded image is further improved by using the compound represented by the general formula (1) in combination with another compound having a xanthene skeleton. The present inventors presume the mechanism of improving the light resistance of an image by using a compound represented by the general formula (1) in combination with another compound having a xanthene skeleton as follows. The compound represented by the general formula (1) has higher cohesiveness and excellent light resistance than other compounds having a xanthene skeleton. Further, the compound represented by the general formula (1) tends to exist on the surface of the recording medium or in the vicinity thereof. For this reason, when an ink containing a colorant containing a compound represented by the general formula (1) and another compound having a xanthene skeleton is applied to the recording medium, the distribution of both is the surface of the recording medium or It is not uniform in the vicinity. As a result, the compound represented by the general formula (1) present at a position closer to the surface of the recording medium can be compared with other compounds having a xanthene skeleton present at a position where the compound penetrates deeply in the thickness direction of the recording medium. It is considered that the light resistance of the image is improved.

  Examples of other compounds having a xanthene skeleton include C.I. As a dye having an I number, C.I. I. Acid red 52 and 289 can be mentioned. In addition, a compound in which the substituent containing a phenyl group bonded to the xanthene mother skeleton through an amino group is the same as the compound represented by the general formula (1) is preferable because the optical density of the image is further improved. Specific examples of such a compound include the dye compound (11) described in Patent Document 1.

  In addition, as long as the effects of the present invention are not impaired, a colorant (other colorant) other than the compound represented by the general formula (1) and other compounds having a xanthene skeleton may be used in combination. In particular, it is preferable to use a compound having an azo skeleton or an anthrapyridone skeleton, which is a color material in the magenta to red region.

(Coloring material content)
The content (% by mass) of the compound represented by the general formula (1) in the ink is preferably 2.0% by mass or less based on the total mass of the ink. When the content is more than 2.0% by mass, the filterability at the time of preparing the ink may be easily lowered. The content (% by mass) of the compound represented by the general formula (1) in the ink is preferably 0.01% by mass or more based on the total mass of the ink.

  In addition to the compound represented by the general formula (1) as the coloring material, when using another compound having a xanthene skeleton, the following is preferable. The content (% by mass) of the other compound having a xanthene skeleton in the ink is preferably 0.01% by mass or more and 10.0% by mass or less based on the total mass of the ink. Further, the (total) content (mass%) of the coloring material in the ink is not particularly limited as long as it satisfies the reliability as an ink jet ink such as ejection characteristics, but is 0 based on the total mass of the ink. It is preferable that it is 0.01 mass% or more and 10.0 mass% or less.

(Color material verification method)
In order to verify whether or not the color material used in the present invention is contained in each ink, the following verification methods (1) to (3) using high performance liquid chromatography (HPLC) can be applied. .
(1) Peak retention time (2) Maximum absorption wavelength for peak of (1) (3) M / Z (posi), M / Z (negative) of mass spectrum for peak of (1)

The analysis conditions by high performance liquid chromatography are as follows. A liquid (ink) diluted about 1,000 times with pure water was used as a measurement sample. Then, an analysis by high performance liquid chromatography is performed under the following conditions, and a peak retention time and a peak maximum absorption wavelength are measured.
Column: SunFire C18 (Nippon Waters) 2.1mm x 150mm
-Column temperature: 40 ° C
・ Flow rate: 0.2 mL / min
PDA: 200 nm to 700 nm
-Mobile phase and gradient conditions: Table 2

The analysis conditions of the mass spectrum are as shown below. The mass spectrum of the obtained peak is measured under the following conditions, and the most strongly detected M / Z is measured for each of posi and negative.
・ Ionization method: ESI
・ Capillary voltage: 3.5 kV
-Desolvent gas: 300 ° C
-Ion source temperature: 120 ° C
·Detector:
posi; 40V 200-1500amu / 0.9sec
nega; 40V 200-1500amu / 0.9sec

  Under the above-described method and conditions, the measurement was performed on the exemplified compound 4 which is a specific example of the compound represented by the general formula (1). As a result, the obtained retention time, maximum absorption wavelength, M / Z (posi), and M / Z (negative) values are shown in Table 3. About an unknown ink, it measures by the method and conditions similar to the above, and when the obtained measured value corresponds to the value shown in Table 3, it can be judged that it contains the compound of this invention.

(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. It is preferable to use deionized water (ion exchange water) as the water. The content (% by mass) of water in the ink is preferably 10.0% by mass or more and 90.0% 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 alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. The content (% by mass) of the water-soluble organic solvent in the ink is 5.0% by mass or more and 90.0% by mass or less, and further 10.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. It is preferable that When the content of the water-soluble organic solvent is less than the above range, reliability such as ejection stability may not be obtained when the ink is used in an ink jet recording apparatus. Further, if the content of the water-soluble organic solvent is larger than the above range, the viscosity of the ink is increased and ink supply failure may occur.

(Additive)
In addition to the components described above, the ink of the present invention is a water-soluble organic substance that is solid at room temperature, such as polyhydric alcohols such as trimethylolpropane and trimethylolethane, and urea derivatives such as urea and ethyleneurea, if necessary. A compound may be contained. Furthermore, the ink of the present invention contains a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, an evaporation accelerator, a chelating agent, and a water-soluble agent as necessary. Various additives such as a functional polymer may be contained. In particular, compounds such as trisodium citrate and the trade name “Proxel GXL” (manufactured by Avicia) can be used particularly suitably for imparting properties such as long-term reliability stability to the ink.

(Ink pH)
The ink of the present invention preferably has a pH at 25 ° C. of 7.0 or more and 10.0 or less. When the pH of the ink exceeds 10.0, the following problems may occur depending on the type of material constituting the member that contacts the ink of the ink cartridge or the inkjet recording apparatus. That is, impurities may elute into the ink and the ink performance may be reduced. Moreover, the material which comprises the member which contacts ink may deteriorate. Further, when recording is performed continuously for a long period of time, deterioration (dissolution) of the liquid contact surface of the heat generating portion of the recording head or disconnection of the wiring may occur. On the other hand, when the pH of the ink is less than 7.0, the solubility of the compound represented by the general formula (1) is lowered, so that the storage stability of the ink may be lowered.

<Ink cartridge>
The ink cartridge of the present invention includes ink and an ink storage unit that stores the ink. And the ink accommodated in this ink accommodating part is the ink of this invention demonstrated above. FIG. 1 is a cross-sectional view schematically showing an embodiment of the ink cartridge of the present invention. As shown in FIG. 1, an ink supply port 12 for supplying ink to the recording head is provided on the bottom surface of the ink cartridge. The inside of the ink cartridge is an ink storage portion for storing ink. The ink storage portion is composed of an ink storage chamber 14 and an absorber storage chamber 16, which communicate with each other via a communication port 18. The absorber housing chamber 16 communicates with the ink supply port 12. Liquid ink 20 is stored in the ink storage chamber 14, and absorbers 22 and 24 that hold the ink in an impregnated state are stored in the absorber storage chamber 16. The ink storage unit may have a form in which the entire amount of ink stored is held by an absorber without having an ink storage chamber for storing liquid ink. Further, the ink storage portion may have a form that does not have an absorber and stores the entire amount of ink in a liquid state. Further, the ink cartridge may be configured to have an ink storage portion and a recording head.

<Inkjet recording method>
The ink jet recording method of the present invention is a method of recording an image on a recording medium by discharging the ink of the present invention described above from an ink jet recording head. Examples of the method for ejecting ink include a method for imparting mechanical energy to the ink and a method for imparting thermal energy to the ink. In the present invention, it is particularly preferable to employ a method in which thermal energy is applied to the ink and the ink is ejected. Other than using the ink of the present invention, the steps of the ink jet recording method may be known.

  2A and 2B are diagrams schematically showing an example of an ink jet recording apparatus used in the ink jet recording method of the present invention. FIG. 2A is a perspective view of a main part of the ink jet recording apparatus, and FIG. 2B is a perspective view of a head cartridge. It is. The ink jet recording apparatus is provided with a conveying means (not shown) for conveying the recording medium 32 and a carriage shaft 34. A head cartridge 36 can be mounted on the carriage shaft 34. The head cartridge 36 includes recording heads 38 and 40, and is configured such that an ink cartridge 42 is set. While the head cartridge 36 is conveyed along the carriage shaft 34 in the main scanning direction, ink (not shown) is ejected from the recording heads 38 and 40 toward the recording medium 32. Then, the recording medium 32 is conveyed in the sub-scanning direction by a conveying unit (not shown), whereby an image is recorded on the recording medium 32.

  EXAMPLES Hereinafter, although an Example, a comparative example, and a reference example are given and this invention is demonstrated further in detail, this invention is not limited at all by the following Example, unless the summary is exceeded. In addition, what is described as “parts” and “%” with respect to the component amounts is based on mass unless otherwise specified.

<Synthesis of coloring materials>
(Exemplary Compound 4)
Resorcinol (2.3 g), 1,3,4-trihydroxybenzene (2.3 g), saccharin (3.6 g) and concentrated sulfuric acid (7.8 g) were reacted by heating at 150 ° C. for 8 hours. Got. The obtained solution was cooled and cold water (50 g) was added, and then the pH of the solution was adjusted to 9 using 25.0% aqueous sodium hydroxide solution. Thereafter, the pH of the solution was adjusted to 1.1 using 35% hydrochloric acid, and the precipitated substance was filtered and dried to obtain a compound (6). Phosphorus oxychloride (30.0 g) was added to 5.7 g of the obtained compound (6), and the mixture was heated to reflux at 110 ° C. for 8 hours. Water (100.0 g) and ice (100.0 g) were added so as to keep the internal temperature at 10 ° C. or lower. The precipitated substance was filtered and dried to obtain 5.0 g of Compound (7).

  3-Isobutyrylamino-2,4,6-trimethylaniline (8.4 g) and compound (7) (5.0 g) in the presence of zinc chloride (2.7 g) in sulfolane (15 mL). The solution was obtained by heating at 150 ° C. for 3 hours for reaction. The obtained solution was cooled and then poured into 50 mL of 2 mol / L hydrochloric acid, and the precipitated crystals were separated by filtration. The obtained crystal was washed with water and dried to obtain 5.1 g of Exemplified Compound 4 (Na salt type).

(Compound A)
Compound A having the following structure was synthesized according to the method described in “Synthesis Example 2” of Patent Document 1 (Japanese Patent Application Laid-Open No. 2011-148873).

<Preparation of ink>
Each component (unit:%) shown in Table 4 was mixed and sufficiently stirred, and then pressure-filtered with a filter having a pore size of 1.2 μm to prepare each ink. “Acetylenol E100” in Table 4 is a trade name of a nonionic surfactant (manufactured by Kawaken Fine Chemicals). Polyethylene glycol having a number average molecular weight of 1,000 was used.

  Each ink of Examples 1 to 3 obtained above is filled in an ink cartridge and mounted on an ink jet recording apparatus (trade name “PIXUS iP8600”, manufactured by Canon) that ejects ink from the recording head by the action of thermal energy. Images were recorded. As a result, an image could be recorded normally.

  Ink of Example 4 was prepared in the same manner as Example 1 except that the content of Exemplified Compound 4 (Na salt) was changed to 2.5% and the water content was changed to 67.5%. As a result, the time required for pressure filtration became longer compared to other inks.

<Evaluation>
The inks of Examples 1 to 3, Comparative Example 1 and Reference Example 1 obtained above were dropped on a recording medium (trade name “Canon Photo Paper / Glossy Pro [Platinum Grade] PT101”, manufactured by Canon Inc.) by 50 μm to form an image. Was recorded to obtain a recorded matter. The obtained recorded matter was dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%. Next, using a spectrophotometer (trade name “Spectorolino”, manufactured by Gretag Macbeth), the color of the image of the recorded material was measured under the conditions of a light source: D50 and a visual field: 2 °. In the present invention, according to the evaluation criteria of the following items, A and B are acceptable levels, and C is an unacceptable level. The evaluation results are shown in Table 5.

(Hue)
L, a, and b were measured for the image portion of the recorded matter obtained above. Note that L, a, and b are L ^* , a ^* , and b ^* in the L ^* a ^* b ^* display system defined by the CIE (International Commission on Illumination). The hue angle (H °) was determined from the obtained values a and b based on the following formula, and the hue was evaluated according to the following evaluation criteria.
When a ^* ≧ 0 and b ^* ≧ 0 (first quadrant), H ° = tan ⁻¹ (b ^* / a ^* )
When a ^* ≦ 0 and b ^* ≧ 0 (second quadrant), H ° = 180 + tan ⁻¹ (b ^* / a ^* )
For a ^* ≦ 0 and b ^* ≦ 0 (third quadrant), H ° = 180 + tan ⁻¹ (b ^* / a ^* )
When a ^* ≧ 0 and b ^* ≦ 0 (fourth quadrant), H ° = 360 + tan ⁻¹ (b ^* / a ^* )
A: H ° was in the first quadrant, and H ° was 15 or more and 35 or less.
B: H ° is not in the first quadrant, or H ° is less than 15 or more than 35.

(Optical density)
The optical density of the image portion of the recorded matter obtained above was measured, and the optical density was evaluated according to the evaluation criteria shown below.
A: The optical density was 2.3 or more.
B: The optical density was 1.9 or more and less than 2.3.
C: The optical density was less than 1.9.

(Light resistance)
The optical density of the image portion of the recorded matter obtained above was measured (referred to as “optical density before test”). Thereafter, the recorded matter was placed in a xenon test apparatus (trade name “Xenon Weather Meter SX-75”, manufactured by Suga Test Instruments Co., Ltd.), and the temperature was 50 ° C., the relative humidity was 60%, and the illuminance was 100 klx. The image was irradiated with xenon light for a time. Next, the optical density of the image portion of the recorded matter was measured (referred to as “optical density after test”). The residual ratio of optical density (%) = (optical density after test / optical density before test) × 100 was calculated, and light resistance was evaluated according to the evaluation criteria shown below.
A: The residual ratio of the optical density was 90% or more.
B: The residual ratio of the optical density was 84% or more and less than 90%.
C: The residual ratio of optical density was less than 84%.

Claims (6)

A compound represented by the following general formula (1):

(In the general formula (1), R ₁ , R ₅ , R ₆ and R ₁₀ each independently represents an alkyl group. R ₃ and R ₈ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or R ₂ , R ₄ , R ₇ and R ₉ each independently represents a hydrogen atom or an acylamino group represented by the following general formula (2), R ₂ , R ₄ , R ₇ and R _At least one of ₉ is an acylamino group represented by the following general formula (2): M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and any one of R _{12 to} R ₂₁ represents a hydroxy group. And the rest represent hydrogen atoms)

(In the general formula (2), R ₁₁ represents an alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, an alkenyl group, or a heterocyclic group, and * represents a bond to an aromatic ring in the general formula (1). (Represents part) An ink containing a coloring material,
An ink, wherein the color material contains the compound according to claim 1.   The ink according to claim 2, wherein the colorant further contains a compound having a xanthene skeleton (excluding the compound represented by the general formula (1)).   The ink according to claim 2 or 3, which is for inkjet. An ink cartridge comprising ink and an ink containing portion for containing the ink,
An ink cartridge, wherein the ink is the ink according to any one of claims 2 to 4. An ink jet recording method for recording an image on a recording medium by discharging ink from an ink jet recording head,
An ink jet recording method, wherein the ink is the ink according to any one of claims 2 to 4.

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