JPH0768475B2 - Inkjet recording liquid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel recording liquid (hereinafter referred to as an ink), and more particularly to an ink suitable for an inkjet recording system that records by using thermal energy.

(Prior art and its problems) A writing instrument (fountain pen,
For example, a felt pen or the like is used as an ink in which various dyes are dissolved in water or other organic solvent.

Further, in the so-called ink jet system in which the ink in the recording head is ejected from the ejection orifice by utilizing the electrostatic attraction or the thermal energy due to the vibration by the piezoelectric vibrator or the high voltage application, various dyes are Ink dissolved in an organic solvent or the like is used. However, in comparison with general fountain pens and stationery inks such as felt pens, inkjet inks have many characteristics and require stricter conditions.

For example, the physical properties such as viscosity and surface tension are within the proper range, the dissolution stability of the recording agent is high, the fine ejection orifices are not clogged, the recorded image of sufficiently high density is given, and the image is stored. In addition, various properties such as changes in physical properties and precipitation of solids are not required. Particularly in the recording system using heat energy, stability against thermal action is also required.

However, conventional inks, especially water-based recorded images, tend to cause bleeding, blurring or fading due to water adhesion or light irradiation, and inks in which these drawbacks have been improved are strongly desired.

From this point of view, many proposals have been made regarding inks, but practical inks that satisfy all the above conditions have not been obtained.

In particular, with regard to red ink, almost no dye is known that has both clear color tone and excellent water resistance and light resistance. That is, a dye having a clear color tone such as a xanthene-based dye has extremely low light fastness, while a dye having a good light fastness such as a metal-containing azo dye has a drawback of lacking a sharp tone.

Therefore, it is an object of the present invention to provide a red ink that satisfies all the above conditions. That is, the purpose of the present invention is to provide an ink having excellent recording properties, ejection stability, ejection response, etc. without causing clogging of the ejection orifice, deterioration of the ejection orifice or generation of precipitate during storage.

Another object of the present invention is to provide an ink having excellent color tone and contrast of a recorded image.

Still another object of the present invention is to provide an ink in which a recorded image is excellent in water resistance, alcohol resistance, light resistance and fixing property.

(Means for Solving Problems) The above object is achieved by the present invention described below.

That is, the present invention is an ink containing a recording material and a solvent, which is characterized by containing the following magenta component and yellow component as the recording material.

(Magenta component) Dye represented by the following general formula (A) and CI Direct Red 227 (However, R ₁ and R ₂ in the above formula represent any substituents, and X
Is a residue of an organic acid, and M represents one kind of base selected from alkali metals, ammonium and organic amines. ) (Yellow component) CI Direct Yellow 86 and / or CI Direct Yellow 142 (Function) In order to achieve the above-mentioned object of the present invention, the present inventor has used a dye as a recording material component of ink, particularly a dye constituting red. As a result of a detailed study of the dyes, a specific combination of dyes is suitable as a recording material for inks, particularly as a recording material for inks used in an inkjet method utilizing heat energy. It was found that an ink which gives a recorded image having extremely clear color tone, water resistance, light resistance, high quality, alcohol resistance, and other required performance can be obtained by using it as a recording agent of No. 1.

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

The dye represented by the above general formula (A) used in the present invention may be any dye as long as it is included in the above general formula (A), and a particularly preferable specific example thereof is, for example, The following are listed. Although sodium salt is mentioned as an example, it is not limited to sodium salt and may be formed with any base such as lithium salt, potassium salt, ammonium salt, organic amine salt and the like.

Exemplified compound-1 Exemplified compound-2 Exemplified compound-3 Exemplified compound-4 Exemplified compound-5 Exemplified compound-6 Exemplified compound-7 Exemplified compound-8 Exemplified compound-9 Exemplified compound-10 Exemplified compound-11 Exemplified compound-12 A magenta component composed of the above dye (A) and CI Direct Red 227, CI Direct Yellow 86 and C.
The main feature of the present invention is to use a yellow component composed of either one or both of I. Direct Yellow 142, and an ink obtained by such a specific combination is more advantageous than a conventional ink of the same color. It provides a recorded image having excellent color tone clarity, light fastness and water fastness.

The total content of the above-mentioned dyes is determined depending on the kind of the solvent component, the properties required for the ink, etc., but generally 0.1 to 2 in weight percent with respect to the total weight of the ink.
0%, preferably 0.5 to 15%, more preferably 1 to 10
The range is%.

Regarding the amount of these dyes used, the total amount of the dye (A) is 10 to 90% by weight, preferably 20 to 70% by weight, and CI Direct Red 227 is 20% by weight.
The effects of the present invention are most remarkably achieved when the composition is used in an amount of 60 to 60% by weight. Of course, in addition to these specific dyes, various other dyes such as direct dyes and acid dyes can be used in combination.

A solvent suitable for use in the ink of the present invention is water or a mixed solvent of water and a water-soluble organic solvent, and a particularly preferable solvent is a mixed solvent of water and a water-soluble organic solvent.

As water, not ordinary water containing various ions,
It is preferred to use deionized water. Examples of the water-soluble organic solvent used by mixing with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-
Butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and other alkyl alcohols having 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketones and ketone alcohols such as acetone and diacetone alcohol; tetrahydrofuran, dioxane, and the like Ethers; Polyalkylene glycols such as polyethylene glycol and polypropylene glycol;
The alkylene group such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol or diethylene glycol has 2 to 6 alkylene groups.
Alkylene glycols containing 1 carbon atom; glycerin; ureas such as urea, thiourea, ethylene urea; ethylene glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether Lower alkyl ethers of polyhydric alcohols such as N-methyl-
2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

Among these many water-soluble organic solvents, polyhydric alcohols such as ethylene glycol, thiodiglycol, and glycerin are used as main solvents, and alkyl alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and n-butyl alcohol are used. It is preferable to use them together, considering that the recording material is plain paper.

The content of the water-soluble organic solvent in the ink is generally 1 to 50% by weight, preferably 5 to 30% by weight based on the total weight of the ink. The content of water at this time is
Although it is determined in a wide range depending on the kind of the solvent component, its composition or desired properties of the ink, it is generally in the range of 10 to 95%, preferably 70% or more in the total weight of the ink. .

The ink of the present invention prepared from such components has recording characteristics (signal responsiveness, droplet formation stability, ejection stability, long-term continuous recording ability, ejection after a long recording pause) by itself. Stability), storage stability, fixability to a recording material, color tone clarity of a recorded image, light resistance, weather resistance, water resistance, alcohol resistance, etc. are well balanced and excellent. In order to further improve such characteristics, various conventionally known additives may be further added and contained.

For example, viscosity adjusting agents such as polyvinyl alcohol, celluloses and water-soluble resins; various surface active agents such as cationic, anionic or nonionic surfactants, diethanolamine, triethanolamine, etc .; pH adjusting agents with buffer solutions, antifungal agents. Agents and the like can be mentioned.

When the ink of the present invention as described above is used in an ink jet recording system utilizing heat energy, various problems of the prior art are solved, and in particular, the dye used in the present invention is stable against heat drop action. Therefore, even if the ink is continuously ejected for a long period of time, foreign matters such as impurities and altered substances will not be accumulated on the surface of the heater in the recording head to disturb the ejection. Of course, the ink of the present invention is also useful for other types of inkjet recording systems.

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

Example 1 Exemplified Compound-9 0.8 parts CI Direct Red 227 0.8 parts CI Direct Yellow 86 0.4 parts Glycerin 3 parts Thiodiglycol 7 parts Isopropyl alcohol 3 parts Ion-exchanged water 85 parts After sufficiently stirring with the above composition, The ink of the present invention was obtained by pressure filtration with a fluorobore filter having a pore size of 0.45 μm (trade name of a filter manufactured by Sumitomo Electric Industries, Ltd.).

Examples 2 to 5 and Comparative Examples 1 to 5 In the same manner as in Example 1, the following components were used, and the other components were in Example 1.
The inks of the present invention and comparative examples were obtained in the same manner as in.

Example 2 Exemplified compound-4 1.0 part CI Direct Red 227 1.0 part CI Direct Yellow 142 0.5 part Urea 5 parts Ethyl alcohol 5 parts Ion-exchanged water 87.5 parts Example 3 Exemplified Compound-9 0.9 part CI Direct Red 227 0.8 part CI Direct Yellow 86 0.3 parts CI Direct Yellow 142 0.1 parts Glycerin 10 parts Ethyl alcohol 2 parts Ion-exchanged water 85.9 parts Example 4 Exemplified compound-6 1.2 parts CI Direct Red 227 1.0 parts CI Direct Yellow 86 0.5 parts Glycerin 6 parts Thiodiglycol 14 Parts Ethyl alcohol 5 parts Ion-exchanged water 72.3 parts Example 5 Exemplified compound-10 1.3 parts CI Direct Red 227 0.7 parts CI Direct Yellow 142 0.3 parts Diethylene glycol 10 parts Ethylene glycol 5 parts Ion-exchanged water 82.7 parts Comparative Example 1 In Example 1 Exemplified Compound-9 was used in place of all the dyes, and the same as in Example 1 except for the above. One composition.

Comparative Example 2 Instead of all the dyes in Example 2, only Exemplified Compound-4 was used, and the other compositions were the same as in Example 2.

Comparative Example 3 Only CI Direct Red 227 was used in place of all the dyes in Example 3, and the same composition as in Example 3 except for the above.

Comparative Example 4 The same composition as in Example 4 except that 2.2 parts of CI Direct Red 9 and 0.5 part of CI Acid Yellow 23 were used in place of all the dyes in Example 4.

Comparative Example 5 The same composition as in Example 5 except that 2 parts of CI Acid Red 131 and 0.3 part of CI Acid Yellow 23 were used in place of all the dyes in Example 5.

Example of use The ink of each of Examples 1 to 5 and Comparative Examples 1 to 5 is an on-demand type multi-head (orifice size: 50 x 40 μm, drive voltage 30V, frequency 4KHz)
Recording was performed on Xerox 4024DP paper, and after naturally drying in a room for 24 hours, water resistance, light resistance and color tone were evaluated. The results are shown in Table 1 below. The evaluation items and conditions are as follows.

Water resistance was evaluated by OD residual rate (%) after soaking in still water for 5 minutes, and 75 to 100% was ○, 60 to 74% was △, and 60
Less than% was defined as x.

The light resistance was evaluated by ΔE (CIEL ^* a ^* b ^* ) after 20 hours of irradiation with an Atlas kissenon fade meter, and 0 to 10 were evaluated as o, 20 to 11 were evaluated as Δ, and 20 or more was evaluated as x.

The color tone was visually evaluated, and a clear red color was evaluated as ◯, a slightly dull red color was evaluated as Δ, and a color which deviated from the red color tone was evaluated as x.

(Effects of the Invention) The ink of the present invention as described above is excellent as an ink in an inkjet recording system, particularly in an inkjet system utilizing heat energy, by using a compounding dye in a specific combination as the recording agent. It has recording characteristics such as long-term storage stability, ejection stability, and ejection responsiveness, and when applied to a recording material, it exhibits excellent ink fixability, especially color tone sharpness, light resistance, water resistance, and alcohol resistance. It is possible to provide a recorded image having excellent properties and high-quality image quality.

Claims (1)

[Claims] 1. A recording liquid containing a recording agent and a solvent, which contains the following magenta component and yellow component as the recording agent. (Magenta component) Dye represented by the following general formula (A) and CI Direct Red 227 (However, R ₁ and R ₂ in the above formula represent any substituents, and X
Is a residue of an organic acid, and M represents one kind of base selected from alkali metals, ammonium and organic amines. ) (Yellow component) CI Direct Yellow 86 and / or CI Direct Yellow 142