JPH07138511A - Ink for ink-jet recording - Google Patents

Abstract

PURPOSE:To obtain the blue ink which is excellent in water resistance, light resistance, color tone, delivery stability, storage stability, and quick-drying property and gives high-quality prints with no ink running by incorporating a specific water-soluble dye, a wetting agent, and a surfactant. CONSTITUTION:This ink contains a water-soluble dye, one or more wetting agents (e.g. diethylene glycol), and one or more surfactants [e.g., CH3(CH2)12O(C2 H4O)3CH2CO0Na]. The dye comprises two or more compounds which are selected from ones represented by formulae I, II, and III (wherein CuPc is the copper phthalocyanine ring represented by formula IV and M is a counter ion selected from an alkali metal, quaternary ammonium, quaternary phosphonium, and an alkanolamine) and in which the ratio of the number of sulfonamide groups to the number of sulfo groups is 1:1 to 5:1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for ink jet recording, and more specifically, it has excellent water resistance, light resistance and color tone, ejection stability and storage stability, and is quick-drying and has no bleeding. The present invention relates to an aqueous blue ink composition showing high print quality.

[0002]

2. Description of the Related Art In an ink jet recording system, an aqueous ink composition to be used must satisfy the following conditions in order to perform good print recording for a long period of time. (1) The ink ejection characteristics are excellent. For that purpose, the viscosity, the surface tension, the specific conductivity and the density of the ink should be included in an appropriate range as the ink characteristics according to the droplet generation method and the droplet flight control method. (2) It has excellent storability. For that purpose, the ink composition may be deposited due to a chemical change during long-term storage, continuous use, or recording pause, and the nozzles may not be clogged, or the physical properties of the ink may not change. (3) The printed and recorded image has a sufficiently high contrast and is a clear image without bleeding. (4) The printed recorded image should dry quickly. (5) The printed and recorded image should be well preserved in terms of water resistance, light resistance, etc., and should be excellent in abrasion resistance.

In order to satisfy these requirements, many proposals have been made so far as inks used for ink jet recording and the like. However, an ink sufficiently satisfying all the above conditions has not yet been obtained. The current situation.
This is mainly due to the dye in the composition of the ink. For example, a higher dye concentration can provide a clear printed image with a higher contrast, but in order to increase the dye concentration, it is necessary that the dye has high dissolution stability. However, it is known that the dissolution stability of the dye greatly affects the storage stability and the ejection stability of the ink.

The usual ink composition is basically a dye,
It is composed of a polyhydric alcohol or ether called a wetting agent and water. As dyes, there are acid dyes, direct dyes, basic dyes, etc., but basic dyes have drawbacks in terms of safety and storage stability, and are not often used as inkjet recording inks. , Acid dyes are used. For example, in the case of blue ink, C.I. I Direct Blue 1,8,71,76,86,108,200,201,
202, 236 and the like, C.I. I Acid Blue 1, 7, 9, 15, 175, 249 and the like are used. However, when an ink containing such a dye is used for ink jet recording, the direct dye has poor solubility, so there is a problem such as nozzle clogging during continuous recording or restart of recording. However, the water resistance and light resistance of the image are poor, and there is a problem in the storability of the image. In particular, copper phthalocyanine dyes have problems in dissolution stability, weather resistance, and particularly water resistance, and many attempts have been made in the past. According to JP-A-3-200883, by keeping the ratio of the number of sulfonamide groups and the number of sulfonic acid groups of copper phthalocyanine within a specific range, the ink weather resistance, storage stability, and ejection stability can be improved. Although it is said that the improvement can be achieved, it is hard to say that sufficient characteristics are obtained in terms of water resistance and drying property, and satisfactory characteristics of bleeding of a printed image are not obtained.

Further, the surfactant has a great influence on the drying property of the printed image. The role of the surfactant is to lower the surface tension of the ink, thereby increasing the penetrability of the ink into the paper, and thereby increasing the drying speed. In Japanese Patent Laid-Open No. 55-29546, the apparent drying property is improved by utilizing the property that a surfactant penetrates into paper or the like, but this formulation has a drawback that it remarkably bleeds depending on the paper type. Japanese Patent Laid-Open No. 58-6752 discloses that
By using an ethylene oxide adduct having an acetylene bond as a surfactant, a quick-drying ink having improved penetrability and less bleeding is disclosed, but this surfactant may interact depending on the dye used at the same time. There is a problem that the drying property is not improved. Further, according to JP-A-60-23793, when dialkylsulfosuccinic acid is added as a surfactant, the drying property is improved and the image quality is less deteriorated. However, sodium dioctylsulfosuccinate or sodium dihexylsulfosuccinate is used depending on paper. There are problems that the pixel diameters are remarkably different and that the activator decomposes on the alkaline side and the activation effect deteriorates during storage.

[0006]

DISCLOSURE OF THE INVENTION The object of the present invention is to solve the problems of the prior art by using an aqueous ink composition, particularly for stable ink jet recording which is excellent in water resistance, quick-drying, and has little color tone change or bleeding depending on the paper type. An aqueous blue ink composition is provided.

[0007]

The ink jet recording ink of the present invention is an ink jet recording ink containing a water-soluble dye, at least one wetting agent, and at least one surfactant. A mixture comprising at least two compounds selected from the compounds represented by the following general formulas (I), (II) and (III) is included, and the number of sulfonamide groups and sulfonic acid groups in the mixture is 1: 1 to 5: It is characterized by using a material having a ratio of 1: 1.

[Chemical 1] (In the formula, CuPc is a copper phthalocyanine ring of the following formula (IV).

[Chemical 2] And M is a counterion representing an alkali metal, quaternary ammonium, quaternary phosphonium or alkanolamine. )

In the ink jet recording ink of the present invention, the counter ion M of the compound of the general formula (I) or (II) is sodium, lithium and / or a quaternary ammonium represented by the following general formula (V). , Quaternary phosphonium or alkanolamine ions.

[Chemical 3] (In the formula, X represents nitrogen or phosphorus, and R ¹ , R ² , R ³ or R ⁴ represents an alkyl group having 1 to ⁴ carbon atoms, a hydroxyl group or a halogenated alkyl group.)

In the ink jet recording ink of the present invention, the surfactant is a polyoxyethylene alkyl ether acetate represented by the following general formula (VI) or a dialkylsulfosuccinate represented by the following general formula (VII). Is desirable. (In the formula, R ⁵ is a linear or branched alkyl group having 13 to 14 carbon atoms, R ⁶ and R ⁷ are linear or branched alkyl groups having 5 to ⁷ carbon atoms, M ′ is a counterion and an alkali metal, It represents quaternary ammonium, quaternary phosphonium or alkanolamine, and n is an integer of 3 to 12.)

Furthermore, in the ink jet recording ink of the present invention, the above formula (VI) or formula (VI) is used.
The counterion M ′ of the carboxylic acid group or sulfonic acid group of the surfactant represented by I) is preferably sodium, lithium and / or quaternary ammonium, quaternary phosphonium or alkanolamine ion.

That is, the present invention relates to a water-based blue ink composition for ink jet recording, particularly to a water-based blue ink composition which is excellent in ejection stability and storage stability and shows high printing quality. By mixing a blue dye, a water-based ink composition having excellent weather resistance, particularly water resistance, quick-drying and high-quality image quality without color tone change and bleeding depending on paper type is presented. Compounds for obtaining ejection stability and storage stability (general formulas (I) and (II))
And (compound represented by (III)), and thirdly, in an aqueous ink composition using the dye, the recording speed of a recorded image is further increased by increasing the penetrability into paper.
In addition, the structure of the surfactant added to obtain high-quality image with less bleeding compared to plain paper in general is presented.
Shows the mode of a surfactant that enhances the permeability of the ink composition and can obtain an image with little deterioration in image quality.

The present invention will be described in more detail below.
The present invention provides a compound represented by the above general formulas (I), (II) and (III) as an ink water-soluble dye containing a water-soluble dye, one or more kinds of polyhydric alcohols and a surfactant. At least two of them are contained at the same time, and the number of sulfonamide groups and the number of sulfonic acid groups in the mixture are set to a ratio of 1: 1 to 5: 1, which is excellent in water resistance and weather resistance,
It is possible to obtain a water-based ink composition that has little color tone change and bleeding depending on the paper type and is excellent in drying property.

The compound represented by the general formula (III) is
Although it is superior to the compound represented by the general formula (I) in properties such as weather resistance, it has a property that long-term storage stability of the ink is deteriorated due to poor solubility. On the contrary, the compound represented by the general formula (I) has high solubility but is inferior in water resistance, weather resistance and color tone. The compound represented by the general formula (II) exhibits properties intermediate between those of the compounds represented by the general formula (I) and the general formula (III). Therefore, by mixing at least two kinds of compounds from the three kinds of compounds and adjusting the ratio of the number of sulfonamide groups and sulfonic acid groups of the mixture to 1: 1 to 5: 1, It has become possible to provide a water-based ink composition which is excellent in weather resistance, particularly water resistance, has little color tone change and bleeding depending on paper type, is quick-drying, and has excellent storage stability. When the ratio of the number of sulfonamide groups to the sulfonic acid groups is larger than 5: 1, the solubility of the dye is lowered and the storage stability of the ink is deteriorated. If it is too small, the weather resistance and color tone will be poor. According to the composition of the present invention, it is possible to provide a water-based ink having excellent weather resistance, particularly water resistance, less color tone change and bleeding depending on paper type, and excellent drying property.

Further, in the present invention, by devising the counterion of the dye or adding a polyhydric alcohol as a wetting agent, an ink having further improved storage stability and ejection stability can be obtained. can get. Further, in order to further improve the drying property of the printed image and to obtain a high-quality image quality without bleeding, it is possible to obtain an ink having sufficient characteristics by specifying the surfactant to be added. In the above dye compound, the counter ion M for obtaining excellent dissolution stability, ejection stability and good printed image is sodium, lithium and / or quaternary ammonium or quaternary ammonium represented by the general formula (V). A phosphonium or alkanolamine ion.

Next, the polyoxyethylene alkyl ether acetate and the dialkyl sulfosuccinate used as the surfactant can be prepared by using the above general formula (VI) or (VI).
Although represented by I), at this time, R ⁵ preferably has 13 carbon atoms. Further, n = 3 is most preferable. R ⁶ and R ⁷ preferably have 5 or 7 carbon atoms. The counter ion M of the carboxylic acid group of the polyoxyethylene alkyl ether acetate or the dialkyl sulfonic acid group is sodium, lithium and / or the following formula (VII
When it is the quaternary ammonium, quaternary phosphonium or alkanolamine ion represented by I), excellent dissolution stability, ejection stability and good printed image can be obtained.

[Chemical 4] (In the formula, X is nitrogen or phosphorus, R ⁸ , R ⁹ , R ¹⁰ and R ¹¹
Represents an alkyl group having 1 to 4 carbon atoms, a hydroxylalkyl group, a halogenated alkyl group or hydrogen. ) The polyoxyethylene alkyl ether acetate or dialkyl sulfosuccinate reduces the surface tension of the ink,
It is added in order to accelerate the drying property of the printed image by increasing the penetrability of the ink into the paper. The addition amount is adjusted so that the surface tension of the ink is usually 50 mN / m or less. 0.0 with respect to the total amount of the ink composition
1 to 3.0% by weight is preferable. If the amount of the surfactant added is less than 0.01% by weight, the dynamic surface tension is high, resulting in poor drying properties. Conversely, if the amount added is more than 3.0% by weight, precipitation of the surfactant during storage, etc. Occurs. Further, the dialkyl sulfosuccinate has a problem that it decomposes when left on the alkaline side, and therefore it is usually used by adjusting the pH. The polyoxyethylene alkyl ether acetate is specifically available as the Nikkor ECT series (manufactured by Nippon Surfactant Co.). The dialkyl sulfosuccinate is available as Aerosol OB-70 (manufactured by Toho Kagaku KK), Aerosol MA-80, AY-100 (manufactured by Mitsui Cyanamid) and the like.

To convert the sulfone group or carboxylic acid group of the dye and surfactant used in the present invention into an alkali salt,
This can be easily performed by adding an alkali hydroxide containing a desired alkali ion when dissolving these in water at the time of preparing the ink. For example, in the case of a lithium salt, it can be carried out by adding lithium hydroxide, and regarding the quaternary ammonium, phosphonium and alkanolamine cations of the formula (V) or (VII), the water specifically shown in Table 1 below is used. This is done by adding an oxide.

[0017]

[Table 1]

In the present invention, the counter ions of the dye or surfactant are all sodium, lithium and / or
Alternatively, the compound does not have to be the compound represented by the above formula (V) or (VII), and can be mixed with other alkali ions. Other preferred counterions are triethanolamine and the like. Sodium, lithium and /
Alternatively, the amount of ions formed by the compound of the general formula (V) or (VII) is 30% or more, more preferably 60%, based on the number of unit moles of the dye or the surfactant.
It is preferable to add it so as to be not less than%.

Tables 2- (1) to 2- (3) show specific examples of the dyes used in the present invention and Table 3 the surfactants used in the present invention, but the present invention is not limited thereto. is not.

[0020]

[Table 2- (1)]

[0021]

[Table 2- (2)]

[0022]

[Table 2- (3)]

[0023]

[Table 3]

The ink of the present invention uses water as a liquid medium, but in order to make the ink have desired physical properties or prevent the ink from drying, and to stabilize the dissolution of the compound used in the present invention. Examples of the penetrant added for the purpose of improving the property include the following.
Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, glycerol, 1,5-pentanediol, 1,6-hexanediol, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1 ，
Polyhydric alcohols such as 2,3-butanetriol and petriol: ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether,
Polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether: Polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether: N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , 1,3-Dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone and other nitrogen-containing heterocyclic compounds: formamide, N-methylformamide, formamide, N, N-dimethylformamide and other amides: monoethanolamine, diethanolamine , Amines such as triethanolamine, monoethylamine, diethylamine and triethylamine: Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane and thiodiethanol: propylene carbonate: Examples include ethylene carbonate. These solvents are used alone or in combination with water.

Of these, particularly preferred are diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4.
-Butanetriol, petriol, N-hydroxyethyl-2-pyrrolidone, and by using these, excellent solubility is obtained for the compound according to the present invention and an excellent effect is obtained for preventing defective injection characteristics due to water evaporation. .

As the penetrant added in addition to the surfactant used in the present invention for the purpose of adjusting the surface tension, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol are used. Alkyl and aryl ethers of polyhydric alcohols such as monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl ether, fluorine-based surfactants, acetylene-based surfactants, ethanol,
Lower alcohols such as 2-propanol can be mentioned, but diethylene glycol monobutyl ether is particularly preferable.

The ink of the present invention contains the above-mentioned coloring agent, solvent,
In addition to the surfactant and the like, conventionally known additives can be added. For example, as antiseptic / antifungal agents, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol and the like can be used in the present invention. Examples of the rust preventive agent include acidic sulfite,
There are sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like. Other water-soluble UV absorbers depending on the purpose,
A water-soluble infrared absorber can be added.

[0028]

EXAMPLES Next, the present invention will be described more concretely with reference to Examples and Comparative Examples.

Examples 1 to 18 and Comparative Examples 1 to 10 Ink compositions formulated with the compositions shown in Tables 4- (1) to 4- (4) were dissolved by stirring at room temperature, and the ink compositions were dissolved. Cyan ink types 1 to 28 were prepared by filtering with a Teflon filter of 0.22 μm and deaeration for about 30 minutes. All the numerical values of the addition amount in the table are% by weight.

[0030]

[Table 4- (1)]

[0031]

[Table 4- (2)]

[0032]

[Table 4- (3)]

[0033]

[Table 4- (4)]

Subsequently, the following tests were carried out on these Examples 1-18 and Comparative Examples 1-10. (1) Image sharpness 300 dp of the thermal inkjet system shown in FIG.
An inkjet printer having an i nozzle, and the laminated PZT shown in FIG.
Printing was performed with an inkjet printer having pi nozzles, and image bleeding, color tone, and density were visually comprehensively judged. As the printing paper, commercially available recycled paper, high-quality paper and bond paper were used. (2) Water Resistance of Image The printed image sample was immersed in water at 30 ° C. for 1 minute, the change in image density before and after the immersion was measured with a Macbeth densitometer, and the water fade resistance rate was calculated by the following formula. (3) Lightfastness of image The printed image sample is irradiated with light by a carbon arc type fade meter at 63 ° C. for 3 hours, and the change in image density before and after light irradiation is measured by a Macbeth densitometer. The fading rate was calculated. (4) Image Drying Property The paper was pressed against the printed image under certain conditions, and the time until the ink was not transferred to the paper was measured. When any of the papers was dried within 10 seconds, it was judged as good (∘) and x was bad. (5) Storage stability Each ink was placed in a polyethylene container, at -20 ° C, 5 ° C,
It was stored under each condition of 20 ° C. and 70 ° C. for 3 months, and the surface tension after storage, the viscosity and the presence or absence of precipitate precipitation were examined. Good even if the physical properties do not change under any conditions (○),
(X) was determined to be defective. (6) Reliability when printing is stopped During operation of the printer having the head shown in FIG. 2, how much time (seconds) can be restored even if printing is stopped without cap and cleaning is checked. The reliability was evaluated based on whether the ejection direction was shifted or the weight of the ejected droplets was changed. The above evaluation results are shown in Table 5- (1) and Table 5.
-Shown in (2).

[0035]

[Table 5- (1)]

[0036]

[Table 5- (2)]

[0037]

According to the first aspect of the present invention, by mixing a specific dye in a specific range, it is excellent in weather resistance, particularly water resistance, and has little color tone change and bleeding depending on paper type, and also has excellent drying property. An excellent water-based ink can be provided. According to the invention of claim 2, it is possible to provide an ink for ink jet recording having excellent ejection stability and storage stability. According to the invention of claim 3, by adding the surfactant having the specified structure, it is possible to enhance the permeability of the ink, thereby suppressing the deterioration of the image quality and preventing the bleeding of plain paper in general. It is possible to provide an aqueous blue ink which gives an image quality and is more dry. According to the present invention of claim 4, excellent solubility stability in water can be improved by selecting a specific dye and a counter ion of a surfactant. An aqueous ink having excellent storage stability and jetting stability can be provided.

[0038]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermal inkjet printer having a 300 dpi ink ejection nozzle.

FIG. 2 is a recording liquid jet printer having a 300 dpi ink ejection nozzle and employing a piezoelectric conversion element.

[Explanation of symbols]

1 ... Ink discharge nozzle, 2 ... Heating element, 3 ... Substrate, 4 ... Nozzle plate, 5 ... Ink liquid chamber, 6 ... Ink supply pipe, 7 ... Liquid chamber flow path, 8 ... Road plate, 9 ... Common liquid chamber, 10 ... Layered PZT (Layered pressure conversion element)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Kaneko 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (4)

[Claims] 1. An inkjet recording ink comprising a water-soluble dye, at least one wetting agent and at least one surfactant, wherein the water-soluble dye is represented by the following general formulas (I), (II) and (III). ) A mixture of at least two compounds among the compounds represented by the formula (1) is used, and the mixture has a ratio of sulfonamide groups and sulfonic acid groups of 1: 1 to 5: 1. Inkjet recording ink. [Chemical 1] (In the formula, CuPc is a copper phthalocyanine ring of the following formula (IV): And M is a counterion representing an alkali metal, quaternary ammonium, quaternary phosphonium or alkanolamine. ) 2. A counter ion M of the compound represented by the general formula (I) or (II) is sodium, lithium and / or a quaternary ammonium, quaternary phosphonium or alkanol represented by the following general formula (V). The inkjet recording ink according to claim 1, which is an amine ion. [Chemical 3] (In the formula, X represents nitrogen or phosphorus, R ¹ , R ² , R ³ and R ⁴ represent an alkyl group having 1 to ⁴ carbon atoms, a hydroxyl group or a halogenated alkyl group.) 3. The ink jet recording according to claim 1, wherein the surfactant is a polyoxyethylene alkyl ether acetate represented by the following general formula (VI) or a dialkylsulfosuccinate represented by the following general formula (VII). Ink. (In the formula, R ⁵ is a linear or branched alkyl group having 13 to 14 carbon atoms, R ⁶ and R ⁷ are linear or branched alkyl groups having 5 to ⁷ carbon atoms, M ′ is a counterion and an alkali metal, It represents quaternary ammonium, quaternary phosphonium or alkanolamine, and n is an integer of 3 to 12.) 4. The counter ion M ′ of the carboxylic acid group or sulfonic acid group of the surfactant represented by the general formula (VI) or (VII) is sodium, lithium and / or quaternary ammonium or quaternary phosphonium. The ink for inkjet recording according to claim 1, which is an alkanolamine ion.