JP2618365B2 - Ink jet recording liquid and ink jet recording method - Google Patents

Description

The present invention relates to an ink jet recording liquid (hereinafter referred to as ink).
More particularly, the present invention relates to an ink jet ink and an ink jet recording method capable of stably forming an image on a recording material such as paper or a resin film.

(Prior Art) The ink jet recording method is a method in which droplets of ink are formed by various ink ejection methods, and a part or all of the droplets are attached to a recording material such as paper to perform recording. .

As an ink jet used in such an ink jet recording method, a recording agent (a dye or a pigment is used)
And a liquid medium for dissolving or dispersing the same (water or various organic solvents or a mixture thereof) is used as a basic component, and those containing various additives as necessary are known and used. I have.

(Problems to be Solved by the Invention) It is natural that various performances are required in the conventional inks as described above, and among them, ink inks for inkjet recording performed by applying thermal energy are most required. The performance, when recording using ink,
The liquid stability is such that there is no deposition of foreign matter on the surface of the heating head due to a temperature change. However, in the case of the conventional ink, if the ejection is performed for a long time, there is a problem in that a foreign substance deposits on the surface of the heating head and the ejection of the ink stops.

It is considered that the deposition of foreign matter may be caused by the presence of various inorganic impurities contained in the ink. However, it is difficult to completely suppress the deposition of the foreign matter even by performing various purification means. Was.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide an ink jet recording method and an ink jet recording method capable of performing stable ejection without depositing foreign matter on the surface of a heating head during ink jet recording. is there.

The above and other objects of the present invention are achieved by the following present invention.

(Means for Solving the Problems) That is, the present invention relates to an ink-jet ink containing at least a water-soluble dye, a water-soluble organic solvent and water, containing a polyphosphonic acid represented by the following general formula (I) or a salt thereof. An ink-jet ink and a method for ink-jet recording using the ink.

(Where M represents a hydrogen, sodium, lithium, potassium or ammonium compound, R ₁ represents an alkyl group having 4 or less carbon atoms, and R ₂ represents an amino group or a hydroxyl group.) (Action) Details of the present inventors According to various studies, the biggest cause of foreign matter deposition on the surface of the heating head during inkjet recording is
Recognizes the presence of divalent or higher metal ions contained in the ink, and increases the dissolution stability by reacting with such metal ions, and further increases the thermal stability on the exothermic heater. It has been found that long-term ink-jet recording becomes possible by incorporating a small amount of polyphosphonic acid or a salt thereof as an agent into the ink.

Means for preventing metal deposition on the exothermic heater with such a small amount of additives has not been known so far, and the present invention solves the problems of the prior art very simply and effectively.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The ink of the present invention corresponds to a conventionally known inkjet ink to which polyphosphonic acid or a salt thereof is added, and the water-soluble dye used in the ink of the present invention includes, for example, a direct dye, an acid dye, a basic dye, and a reactive dye. A water-soluble dye represented by a coloring dye, an edible dye, and the like, which is particularly suitable as an ink of an ink jet recording method, and which satisfies the required performance of sharpness, water solubility, stability, light resistance, and the like includes, for example, , CI Direct Black 17, 19, 32, 51, 71, 108, 14
6; CI Direct Blue 6, 22, 25, 71, 86, 90, 106, 1
99; CI Direct Red 1, 4, 17, 28, 83; CI Direct Yellow 12, 24, 26, 86, 98, 142; CI Direct Orange 34, 39, 44, 46, 60; CI Direct Violet 47, 48; Direct dyes such as CI Direct Brown 109 and CI Direct Green 59, CI Acid Black 2, 7, 24, 26, 51, 52, 63, 11
2, 118; CI Acid Blue 9, 22, 40, 59, 93, 102, 104, 11
3, 117, 120, 167, 229, 234; CI Acid Red 1, 6, 32, 35, 37, 51, 52, 80,
85, 87, 92, 94, 115, 180, 256, 317, 315; CI Acid Yellow 11, 17, 23, 25, 29, 42, 61, 7
1; Acid dyes such as CI Acid Orange 7, 19 and CI Acid Violet 49 are preferred, and CI Basic Black 2; CI Basic Blue 1, 3, 5, 7, 9, 24, 25, 2
6, 28, 29; CI Basic Red 1, 2, 9, 12, 13, 14, 37; CI Basic Violet 7, 14, 27 and CI Food Black 1, 2, etc. can also be used.

The examples of the above dyes are particularly preferable for the ink of the present invention, and the dyes used in the ink of the present invention are not limited to these dyes.

Such a water-soluble dye is generally used in a ratio of about 0.5 to 15% by weight in a conventional ink, and the same may be used in the present invention.

The solvent used in the ink of the present invention is a mixed solvent solution of water and a water-soluble organic solvent, and particularly preferably contains a polyhydric alcohol having a drying prevention effect of the ink as a water-soluble organic solvent. .

As the water, it is preferable to use deionized water instead of general water containing various ions.

Examples of the water-soluble organic solvent used by mixing with water include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol. Alkyl alcohols having 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylenes such as polyethylene glycol and polypropylene glycol Glycols: ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol,
Alkylene glycol acids whose alkylene group contains 2 to 6 carbon atoms, such as hexylene glycol and diethylene glycol; glycene; ethylene glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ) Lower alkyl ethers of polyhydric alcohols such as ethers; N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like.

Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferred.

The content of the water-soluble organic solvent in the ink is generally preferably in the range of 10 to 80% by weight, more preferably 20 to 50% by weight, based on the total weight of the ink.

The content of water at this time is determined in a wide range depending on the kind of the solvent component, its composition, or desired characteristics of the ink, but is generally 10 to 90 with respect to the total weight of the ink.
% By weight, preferably 10 to 70% by weight, more preferably 20% by weight.
To 70% by weight.

Specific examples of the polyphosphonic acid or a salt thereof used in the present invention and mainly characterizing the present invention include the following, but the present invention is not limited to these substances as long as it is included in the general formula. .

Specific examples of compounds of general formula (I) The polyphosphonic acid or salt thereof as described above is preferably 0.01 to 100 parts by weight of the ink of the present invention.
When used in an amount of from 3 to 3 parts by weight, the thermal stability of divalent or higher valent metal ions in the ink is improved, and the problem of foreign matter deposition on the heating head during ink jet recording is sufficiently solved. I can do it.

In addition, the ink of the present invention may further include conventionally known dispersants, surfactants, viscosity modifiers, surface tension modifiers, and the like, if necessary, in addition to the above components. Further, thermal properties (for example, specific heat, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.

The ink jet recording method of the present invention is an ink jet recording method characterized by using the ink of the present invention, and a large number of ink jet recording methods are conventionally known. Can be used. A particularly preferable method in the present invention is a method in which ink is ejected by thermal energy, and even if this method is used, it is possible to stably eject ink without depositing foreign matter on the heating head.

The recording material to be used may be any of ordinary paper, coated paper, synthetic paper, various plastic films, etc., and is not particularly limited.

(Effects of the Invention) The ink of the present invention obtained as described above sufficiently solves the problems of the prior art, and the recording characteristics (signal responsiveness, stability of droplet formation, and the like) of the ink jet system as they are are obtained. Ejection stability, long-time continuous recording, ink ejection stability after long-time operation suspension), storage stability, fixing to recording material, light resistance of recorded images, weather resistance, etc. It is particularly excellent as an ink of an ink jet recording system using thermal energy which is least likely to generate deposits on a heating heater, and an image of excellent quality can be stably obtained.

(Examples) Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the description, parts and% are based on weight unless otherwise specified.

Example 1 Ion-exchanged water (hereinafter abbreviated as water) 56.9 parts Diethylene glycol 20 parts Thiodiglycol 20 parts CI acid red 35 3 parts Compound of the above-mentioned specific example A-1 0.1 part The above components were thoroughly mixed and dissolved in a container. 0.45μm pore size
After filtration under pressure with a Teflon filter described above, the ink of the present invention was obtained by deaeration using a vacuum pump. In the following Examples 2 to 5 and Comparative Examples 1 to 5, inks of the present invention and Comparative Examples were prepared in the same manner.

Example 2 69.7 parts of water 18 parts of ethylene glycol 8 parts of glycerin 8 parts of CI direct red 9 2 parts 0.3 parts of the compound of the specific example A-2 Example 3 60.5 parts of water polyethylene glycol (average molecular weight 300) 20 parts 227 4 parts 0.5 parts of the compound of Specific Example A-3 Example 4 54.8 parts of water 18 parts of N-methyl-2-pyrrolidone 18 parts of polyethylene glycol (average molecular weight 300) 22 parts 5 parts of CI Acid Red 131 5 parts of the specific example A-4 Compound 0.2 part Example 5 Water 66.5 parts Glycene 5 parts Ethylene glycol 25 parts CI Direct Yellow 142 3 parts Compound of the above-mentioned specific example A-5 0.5 part Comparative Example 1 Water 57 parts Diethylene glycol 20 parts Thiodiglycol 20 parts CI Acid Red 35 3 parts Comparative Example 2 Water 70 parts Ethylene glycol 18 parts Glucerin 10 parts CI Direct Red 9 2 parts Comparative Example 3 Water 61 parts Po Ethylene glycol (average molecular weight 300) 30 parts Glycerin 5 parts CI Direct Red 227 4 parts Comparative Example 4 Water 55 parts N-methyl-2-pyrrolidone 18 parts Polyethylene glycol (average molecular weight 300) 22 parts CI Acid Red 131 5 parts Comparative Example 5 Water 67 parts Glycerin 5 parts Ethylene glycol 25 parts CI Direct Yellow 142 3 parts Evaluation items and evaluation methods The inks of Examples 1 to 5 and Comparative Examples 1 to 5 were used, and the ink ejection energy was used as an ink jet recording apparatus. Using an inkjet printer (Canon BJ80) using a heating element as a source, 20 to 20 respectively
A continuous discharge (frequency 2 KHZ) for 0 hours was performed, and the following examination was performed (the evaluation results are shown in Table 1 below).

Test 1 Evaluation of print quality Changes in print quality before and after continuous ejection were visually observed.

：: No change.

Δ: Character distortion is slightly observed.

×: Printing was severely disturbed and characters could not be distinguished.

Test 2 Discharge Response Discharge response (frequency characteristics) before and after continuous discharge was observed.

：: No change.

Δ: Irregularity of ink ejection response.

X: The ink ejection response becomes extremely irregular, and in the worst case, the ink ejection stops.

Test 3 Deposits on the exothermic heater The recording head was disassembled, and the deposit of foreign substances on the exothermic heater was observed using a microscope.

：: No deposit on the heater.

Δ: A small amount of deposit was generated on the heater.

X: A large amount of deposits were generated on the heater.

Claims (4)

(57) [Claims] 1. An ink jet recording liquid containing at least a water-soluble dye, a water-soluble organic solvent and water, comprising a polyphosphonic acid represented by the following general formula (I) or a salt thereof. (Where M represents a hydrogen, sodium, lithium, potassium or ammonium compound, R ₁ represents an alkyl group having 4 or less carbon atoms, and R ₂ represents an amino acid or a hydroxyl group.) (2) Polysulfonic acid or a salt thereof is used in an amount of 0.1% in the recording liquid.
2. The ink jet recording liquid according to claim 1, which accounts for 01 to 3.0% by weight. 3. An ink jet recording method for discharging a recording liquid to perform recording on a recording material, wherein the recording liquid comprises at least a water-soluble dye, a water-soluble organic solvent, water and a polyphosphonic acid represented by the following general formula (I). Or a recording liquid containing a salt thereof. (Where M represents a hydrogen, sodium, lithium, potassium or ammonium compound, R ₁ represents an alkyl group having 4 or less carbon atoms, and R ₂ represents an amino group or a hydroxyl group.) 4. The ink jet recording method according to claim 3, wherein the ink jet recording method is a method in which a recording liquid is discharged by using heat energy.