JPH10101975A - Ink jet recording ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording ink which can give dots reduced in the dispersion of their diameters and which is reduced in temperature dependency. SOLUTION: This ink essentially consists of a colorant, a water-soluble organic solvent, water, 0.01-5.0wt.%, based on the total weight of the ink, acetylene glycol/alkylene oxide adduct represented by the formula (wherein R1 to R4 are each a lower alkyl; l is an integer of 2 or 3; and m and n are each an integer of 1 or greater), and 0.01-2.0wt.%, based on the total weight of the ink, mixture of NaOH with at least either NaHCO3 or Na2 B4 O7 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink used in an ink jet recording type printer.

[0002]

2. Description of the Related Art In general, inks used in ink jet recording type printers are known in which various coloring materials are dissolved or dispersed in water or a medium comprising water and various organic solvents. In order to reproduce a color image, inks of each color of yellow, cyan, magenta, and black have been put to practical use.

[0003] Ink jet recording inks are required to be excellent in defoaming properties, because bubbles are generated in the ink flow path in the recording head, resulting in missing dots in the recorded image. In order to provide an ink having excellent defoaming properties, for example, JP-A-6-256696 proposes to use an acetylene glycol-based surfactant.

[0004] However, the ink described in the above publication is
It does not satisfy the high storage stability required for ink jet recording inks, especially the storage stability against sudden temperature changes. Further, it cannot be said that the characteristics required for the ink are sufficiently achieved, for example, the surface tension and the viscosity change depending on the temperature, and the dot diameter varies at the time of printing.

[0005]

SUMMARY OF THE INVENTION The present invention provides an ink jet recording ink which has high storage stability and small variation in dot diameter at the time of printing, and has a small temperature dependency at an actual use temperature. The purpose is to do.

[0006]

According to the present invention, at least a coloring material, a water-soluble organic solvent, water and the total weight of the ink are represented by the formula (A):

[0007]

Embedded image

Wherein R _{1 to} R ₄ are lower alkyl groups, l is an integer of 2 or 3, and m and n are integers of 1 or more.
0.01 to 5.0% by weight of an acetylene glycol alkylene oxide adduct represented by the formula: NaOH and NaHC
O ₃ and Na ₂ B ₄ mixture of O ₇ of at least one compound selected from the group consisting of the containing 0.01 to 5.0 wt%, an inkjet recording ink.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Coloring materials used in the ink of the present invention include acid dyes, direct dyes, basic dyes, reactive dyes, and the like.
Food dyes, disperse dyes, oil-soluble dyes, vat dyes, various pigments and the like can be used, and among them, water-soluble dyes are preferable. The content of the colorant in the ink composition is determined by the type of the colorant and the ink medium component, the characteristics required for the ink, and the like, but is generally 0.5 to 10% by weight, preferably 2 to 6% by weight in the ink. It is contained in the range of weight%.

The ink for ink jet recording needs to adjust the surface tension of the ink to a certain range in order to suppress the bleeding of the ink and to stabilize the nozzle dischargeability of the ink jet recording apparatus. Usually, a surfactant is added to the ink. In the present invention, the surface tension of the ink is reduced by adding the alkylene oxide adduct of acetylene glycol represented by the above formula (A) as a surfactant to the ink. 30 to 50 dyn / cm (25
℃). Since the surfactant of the formula (A) hardly changes due to the temperature of the compound itself, the use of the surfactant improves the stability of the surface tension and the viscosity with respect to the temperature change of the ink.

In the formula (A), R ₁ and R ₂ are the same lower alkyl group having 1 to 5 carbon atoms, preferably 2 carbon atoms.
And 4 lower alkyl groups, particularly preferably an isobutyl group. R ₃ and R ₄ are the same lower alkyl group having 1 to 5 carbon atoms, preferably a methyl group. As the alkylene oxide to be added, ethylene oxide and propylene oxide are preferable. Particularly preferred is ethylene oxide. m and n may be the same or different, and m + n is 2 to 60, preferably 2 to 30, and more preferably 6 to 20.

As the alkylene oxide adduct of acetylene glycol, a commercially available product of formula (A) wherein R ₁ = R ₂ = isobutyl, R ₃ = R ₄ = methyl and l = 2, Olfin E1004 (m + n = 3.5) ) (Manufactured by Nissin Chemical Industry Co., Ltd.), Olfin E1010 (m + n = 10) (manufactured by Nissin Chemical Industry Co., Ltd.) and Surfynol 485 (m + n = 3)
0) (manufactured by AIR PRODUCTS, USA) are known, and any of them is suitably used for the ink of the present invention.

The ink of the present invention contains 0.01 to 5% by weight of an alkylene oxide adduct of acetylene glycol,
Preferably from 0.1 to 5% by weight, more preferably from 0.1 to 2% by weight.
It is contained in the range of weight%. If it is less than 0.01%, the effect of enhancing the stability by the addition becomes insufficient, and 5%
If the amount is larger, the stability of the ink against a change in temperature is lowered, which is not preferable.

The ink of the present invention comprises NaOH and NaHCO
₃ and Na ₂ B ₄ O _{7 in} a mixture with at least one compound selected from the group consisting of
The content is 0.01 to 2% by weight, preferably 0.05 to 1% by weight. The weight ratio of NaOH to NaHCO ₃ or the like in the mixture is preferably adjusted to 1: 2 to 1:50, preferably 1: 5 to 1:30. By adding these mixtures, high storage stability against a sudden temperature change and stability against a temperature change within an actual use temperature, which cannot be achieved by the prior art, are achieved, and nozzle clogging is also eliminated. . Further, variation in dot diameter, which is a problem in the related art, is suppressed.

The water-soluble organic solvent used in the ink of the present invention is preferably a polyhydric alcohol having 3 hydroxyl groups, wherein OH (CxH _2x O) _y H (where x and y are 2 ≦ x and 2 ≦ x (Indicating an integer satisfying × y ≦ 6), a (mono, di, tri) alkylene glycol, a lower alkyl ether of the (mono, di, tri) alkylene glycol and a mixture thereof. Including. Glycerin is illustrated as a polyhydric alcohol having 3 hydroxyl groups.

As the (mono, di, tri) alkylene glycol, ethylene glycol, propylene glycol,
Monoalkylene glycols such as butylene glycol and hexylene glycol, dialkylene glycols such as diethylene glycol and dipropylene glycol, and trialkylene glycols such as triethylene glycol are exemplified. When a polyhydric alcohol is used as the water-soluble organic solvent, it is preferably added in an amount of 1 to 20% by weight, preferably 6 to 14% by weight, based on the total amount of the ink.
When a (mono, di, tri) alkylene glycol is used, it is preferably added in an amount of 1 to 30% by weight, preferably 6 to 14% by weight, based on the total weight of the ink.

Examples of the lower alkyl ether of (mono, di, tri) alkylene glycol include ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, triethylene glycol butyl ether and the like. When a lower alkyl ether of (mono, di, tri) alkylene glycol is contained, the content is preferably 1 to 30% by weight, especially 4 to 10% by weight based on the total weight of the ink.

The water-soluble organic solvent used in the ink of the present invention preferably contains a polyalkylene glycol having a molecular weight of 150 or more. As the polyalkylene glycol having a molecular weight of 150 or more, polyethylene glycol, polypropylene glycol and a copolymer of ethylene oxide and propylene oxide are preferably used. In particular, polyethylene glycol having a molecular weight of 150 to 600 is preferably used. The content of the polyalkylene glycol is preferably 2 to 8% by weight based on the total weight of the ink.

By adding the above-mentioned polyhydric alcohol, (mono, di, tri) alkylene glycol, lower alkyl ether of (mono, di, tri) alkylene glycol and polyalkylene glycol, the moisturizing property of the ink is improved. It is also useful for stabilizing viscosity and surface tension. The total amount of the polyhydric alcohol, the (mono, di, tri) alkylene glycol, the lower alkyl ether of the (mono, di, tri) alkylene glycol and the polyalkylene glycol is from 10 to the total weight of the ink.
It is added in an amount of 30% by weight, preferably 13 to 25% by weight. If the addition amount is less than 10% by weight, the above effect cannot be achieved. If the addition amount exceeds 30% by weight, the viscosity of the ink becomes too high, the ink flying response and the replenishing property decrease, and the fixing speed also decreases. It is not preferable because it becomes slow.

The ink of the present invention preferably contains an aliphatic alcohol. As the aliphatic alcohol, an alkyl alcohol having 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, and isopropyl alcohol, is used. Aliphatic alcohol accounts for 0.1 to 15 of the total weight of the ink.
% By weight, more preferably 1 to 6% by weight. The addition of the aliphatic alcohol improves the drying property of the ink and improves the fixing property of the ink. However, this effect cannot be obtained if the addition amount is small, and if the addition amount exceeds 15% by weight, clogging of the nozzle and the like may occur. This is not preferable because inconvenience is likely to occur.

The ink of the present invention preferably contains an amphiphile. Examples of the amphiphilic substance include urea, amide, cyclic amide, and alkanolamine, and alkanolamine such as triethanolamine is particularly preferable. The amphiphile is used in an amount of 0.01 to 0.01% based on the total weight of the ink.
The content is 5% by weight, preferably 0.1 to 2% by weight. By adding an amphiphilic substance to the ink, the precipitation of crystals with the lapse of time is prevented and the stability of the ink is increased. However, if the amount is less than 0.01% by weight, the effect cannot be obtained. % Is not preferable because bleeding increases.

The ink of the present invention preferably contains an alkali metal salt of ethylenediaminetetraacetic acid.
Examples of the alkali metal salt of ethylenediaminetetraacetic acid include a disodium salt, a trisodium salt, and a tetrasodium salt, and a tetrasodium salt is particularly preferable. The addition of ethylenediaminetetraacetate prevents clogging of the nozzle discharge port, and improves the stability of the ink against environmental changes such as temperature and humidity. Ethylenediaminetetraacetate is 0.0 with respect to the total weight of the ink.
The content is 1 to 2% by weight, preferably 0.05 to 1% by weight. If it is less than 0.01% by weight, the effect of the addition cannot be obtained, and if it exceeds 2% by weight, the stability of the ink is adversely affected, which is not preferable.

The ink of the present invention may contain known additives as necessary in addition to the above-mentioned components. Examples of the additive include an antifungal agent, a preservative, a pH regulator, a chelating agent, an oxygen absorber, a rust inhibitor, a quencher and the like. The ink of the present invention contains 60 to 90% by weight of water, more preferably 70 to 9% by weight.
It contains 0% by weight.

The ink for ink-jet recording of the present invention comprises:
Any type of ink jet recording type printer can be applied. Since the ink of the present invention has a very low temperature dependency of viscosity and surface tension, it is particularly suitable for an ink jet recording apparatus using a piezo method in which a flying voltage is changed to change a diameter of an ink to be ejected to reproduce gradation. It can be suitably used.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples.

EXAMPLES The components of the following Examples and Comparative Examples were mixed and dissolved with sufficient stirring. After the obtained mixture was filtered, the mixture was allowed to stand for 1 hour in a vacuum state to remove bubbles, thereby preparing an ink. The olphin used in the following Examples
E1010 (manufactured by Nissin Chemical Industry Co., Ltd.)
₁ = R ₂ = isobutyl, R ₃ = R ₄ = methyl, l = 2, m +
It is a compound where n = 10.

Example 1 Composition Composition ratio (% by weight) Water 80.8 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.3 C.I. I. 27755 (black dye) 4.5 Orfin-E1010 (Nissin Chemical Industry Co., Ltd.) 0.7 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 EDTA4Na 0.2 1 , 2-Benzoisothiazolin-3-one (fungicide) 0.1 Ethyl alcohol 2.0

Example 2 Composition Composition ratio (% by weight) Water 83.9 Triethylene glycol butyl ether 6.5 Polyethylene glycol (# 300) 4.5 CI 27755 (black dye) 4.3 Olfin-E1010 (JP) 0.1 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 EDTA4Na 0.2 1,2-benzoisothiazolin-3-one 0.1

Example 3 Composition Composition ratio (% by weight) Water 71.0 Diethylene glycol 12.2 Polyethylene glycol (# 400) 4.0 CI27755 (black dye) 5.5 Orfin-E1010 (Nissin Chemical Industry) _{) 4.5 N (CH 2 CH 2} OH) 3 0.9 Na 2 B 4 O 7 / NaOH (19: 1) 0.6 EDTA4Na 1.2 1,2- benzisothiazolin-3-one 0.1

Example 4 Composition Composition ratio (% by weight) Water 65.1 Diethylene glycol 14.0 Triethylene glycol polyethylene ether 7.0 Polyethylene glycol (# 400) 4.5 CI 19140 (Yellow dye) 2.6 Orphin -E1010 (Nissin Chemical Industry) 2.8 N (CH ₂ CH ₂ OH) ₃ 1.8 NaHCO ₃ / NaOH (19: 1) 0.8 EDTA4Na 1.3 1,2-Benzoisothiazolin-3-one 0 .1

Example 5 Composition Composition ratio (% by weight) Water 80.8 Diethylene glycol 6.2 Polyethylene glycol (# 300) 4.3 CI.45100 (Magenta dye) 2.5 Orfin-E1010 (Nissin Chemical Industry) 1.2) N (CH ₂ CH ₂ OH) ₃ 2.2 NaHCO ₃ / NaOH (19: 1) 0.4 EDTA4Na 1.5 1,2-Benzoisothiazolin-3-one 0.1 Isopropyl alcohol 0.8

Example 6 Composition Composition ratio (% by weight) Water 84.8 Triethylene glycol methyl ether 6.5 Polyethylene glycol (# 200) 4.2 CI 74180 (cyan dye) 3.0 Olfin-E1010 (day) Shin-Kagaku Kogyo) 0.8 N (CH ₂ CH ₂ OH) ₃ 0.2 Na ₂ B ₄ O ₇ / NaOH (19: 1) 0.2 EDTA4Na 0.2 1,2-benzoisothiazolin-3-one 0.1

Example 7 Composition Composition ratio (% by weight) Water 80.5 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (black dye) 4.5 Orfin-E1010 (Nissin Chemical Industry) 0.8 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl alcohol 2.0

Comparative Example 1 Composition Composition ratio (% by weight) Water 81.3 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (black dye) 4.5 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl alcohol 2.0

Comparative Example 2 Composition Composition ratio (% by weight) Water 75.8 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (black dye) 4.5 Orfin-E1010 (Nissin Chemical Industry) 5.5 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl alcohol 2.0

Comparative Example 3 Composition Composition ratio (% by weight) Water 80.5 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (Black dye) 4.5 Polyether Modified silicone oil TSF4452 (Toshiba Silicone) 0.8 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 0.2 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl Alcohol 2.0

Comparative Example 4 Composition Composition ratio (% by weight) Water 80.7 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (black dye) 4.5 Orfin-E1010 (Nissin Chemical Industry) 0.8 N (CH ₂ CH ₂ OH) ₃ 0.2 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl alcohol 2.0

Comparative Example 5 Composition Composition ratio (% by weight) Water 77.7 Diethylene glycol 7.0 Polyethylene glycol (# 400) 4.5 CI 27755 (black dye) 4.5 Orfin-E1010 (Nissin Chemical Industry) 0.8 N (CH ₂ CH ₂ OH) ₃ 0.2 NaHCO ₃ / NaOH (19: 1) 3.0 Sodium gluconate 0.2 1,2-Benzoisothiazolin-3-one 0.1 Ethyl alcohol 2.0

25 of the inks of the obtained Examples and Comparative Examples
The surface tension at ℃, viscosity and pH, storage stability against thermal shock, and temperature dependence of surface tension and viscosity were examined. In addition, when the obtained ink was used for printing on an actual machine, variations in dot diameter and nozzle clogging were measured. The measuring method is as follows:

1) Storage property against thermal shock The ink stored at 25 ° C. in a polyethylene bottle is kept at -20 ° C. and 50 ° C. for 1 hour, respectively. Given repeatedly for a week. Before and after that, the viscosity (25 ° C.) was measured, and the rate of change was ranked as follows. Δ: Change rate 5% or less, Δ: Change rate 10% or less (no problem in practical use), ×: Change rate 10% or more (cannot be used)

2) Temperature Dependence The rate of change in surface tension and viscosity at ink temperatures of 10 ° C. and 35 ° C. was measured. Change rate 1)
It was ranked the same as.

3) Test of actual machine Inkjet printer (MJ-500) manufactured by Epson Corporation
Was used.

Variation in dot diameter: The ink was filled in the head of the printer, and the variation in the diameter of each dot when 100 dots were printed was measured. The measurement was performed under the conditions of 25 ° C. and 65% RH using SF paper manufactured by Epson Corporation.

Nozzle clogging test: high temperature, high humidity (35
Color chart (20% coverage test chart, A) at 100 ° C., 85% RH)
4) was printed on SF paper manufactured by Epson Corporation. The nozzle clogging after printing was observed with a microscope. In addition, the nozzles were cleaned with a cleaning rubber blade provided on the MJ-500 when foreign matter was attached. Evaluation was performed as follows: 〇: No foreign matter adhered around the nozzle, and good use was possible. Δ: Foreign matter adhered around the nozzle, but foreign matter was removed by cleaning. There is no substantial problem in printing performance. X: Foreign matter was adhered around the nozzle, and the dots were thinned and fuzzy. Some nozzles are not recovered by cleaning, and cannot be used. In each of the above tests, "△" was set to "no problem in practical use" based on the evaluation in binary printing used in Examples. Therefore, even when the evaluation of △ is obtained, it is considered that there is a practical disadvantage when the dot diameter is reduced or when the dot diameter is changed to perform gradation printing.
Table 1 shows the results.

[0044]

[Table 1]

[0045]

As described above, the ink of the present invention has good storage stability against a sudden change in temperature, and has achieved printing with a small variation in dot diameter which could not be achieved conventionally. Further, there is no clogging of the nozzles due to the use of the ink, and the physical properties hardly change between 10 ° C. and 35 ° C., which is the temperature at which the ink is usually used, so that extremely stable and high quality printing is possible.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masami Asano 2-313 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Hideo Hotomi Azuchi-cho, Chuo-ku, Osaka-shi, Osaka 2-3-13 Osaka International Building Minolta Co., Ltd.

Claims (6)

[Claims] At least a coloring material, a water-soluble organic solvent, water,
And the formula (A) with respect to the total weight of the ink: (Wherein, R _{1 to} R ₄ are lower alkyl groups, l is an integer of 2 or 3, m and n are each an integer of 1 or more), and the alkylene oxide adduct of acetylene glycol represented by 0.01 to 5.0. 0 wt%, a mixture of at least one compound selected from the group consisting of NaOH and NaHCO ₃ and Na ₂ B ₄ O ₇ containing 0.01 to 2.0 wt%,
Ink for inkjet recording. 2. The water-soluble organic solvent is a polyhydric alcohol having 3 hydroxyl groups, a formula: HO (C _x H _2x O) _y H (where x and y are 2 ≦ x and 2 ≦ x × y ≦ 6) Wherein the compound is selected from the group consisting of (mono, di, tri) alkylene glycols, lower alkyl ethers of the (mono, di, tri) alkylene glycols, and mixtures thereof. 2. The ink jet recording ink according to 1. 3. A water-soluble organic solvent containing a polyalkylene glycol having a molecular weight of 150 or more in an amount of 2 to 2 parts by weight based on the total weight of the ink.
3. The ink jet recording ink according to claim 1, comprising 8% by weight. 4. The total content of the polyhydric alcohol, the (mono, di, tri) alkylene glycol, the (mono, di, tri) alkylene glycol lower alkyl ether and the polyalkylene glycol is 10 to 3 with respect to the total weight of the ink.
The ink for inkjet recording according to claim 3, which is 0% by weight. 5. The ink jet recording ink according to claim 1, further comprising an aliphatic alcohol having 1 to 5 carbon atoms in an amount of 0.1 to 15% by weight based on the total weight of the ink. 6. The ink for inkjet recording according to claim 1, further comprising 0.01 to 5% by weight of an alkanolamine based on the total weight of the ink.