JPH1017804A - Water-base magenta recording ink and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-base magenta recording ink having a good hue as magenta and improved liquid stability, delivery stability and clarity by dissolving Color Index Number Acid Red 52 in a mixed solvent comprising water and 2-pyrrolidinone. SOLUTION: 0.1-5wt.% Color Index Number Acid Red 52 and optionally a dispersant, a surfactant, a viscosity modifier, a surface tension modifier, a pH modifier, etc., are dissolved in a mixed solvent comprising 10-95wt.% deionized water and 5-50wt.% 2-pyrrolidinone as a water-soluble organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous recording magenta ink and an ink jet recording method.

[0002]

2. Description of the Related Art Ink jet recording methods include, for example, an electrostatic suction method, a method of applying mechanical vibration or displacement to ink using a piezoelectric element, and generating bubbles by heating the ink. Ink droplets are formed by various ink ejection methods such as a method of utilizing the ink droplets, and a part or all of the ink droplets are attached to a recording material such as paper to perform recording.

Conventionally, as ink compositions used in such an ink jet recording method, an ink composition using a dye as a colorant and an ink composition using a pigment have been developed.

[0004] Ink jet recording ink compositions include:
The clogging should not occur at the head of the recording device or in the ink flow path, no change in physical properties or precipitation of solids should occur during storage, and a sufficiently high-density recorded image should be provided with a clear color tone. Recording can be performed without limiting the type of recording material, fast fixing speed to the recording material, excellent water resistance, weather resistance, solvent resistance, abrasion resistance, and images with excellent resolution It is required to provide performances such as giving properties, physical properties such as viscosity and surface tension within an appropriate range.

[0005] Pigments are often used in the field of coatings and the like because they have better water resistance and weather resistance than dyes. However, since pigments are not dissolved but dispersed in an ink medium, they are used in liquids. Inferior in stability, and when stored for a long period of time, dispersion of the pigment becomes unstable and aggregation occurs. For this reason, compared with the dye ink composition, the pigment ink composition is more likely to cause clogging at the tip of the head of the ink jet printer or in the ink flow path. For this reason, there are few examples that are commercialized for inkjet printers, and many are still in the development stage.

[0006] On the other hand, although dyes are inferior in water resistance and weather resistance to pigments, they are completely dissolved in the ink medium, so that the dye ink composition can be used at the tip of an ink jet printer head or in the ink flow path. It is hardly clogged and has much better liquid stability than the pigment ink composition.
Therefore, many dye ink compositions have been commercialized for inkjet printers. Among such dye ink compositions, an aqueous dye ink composition in which a dye is dissolved in water is dominant. Such aqueous dye ink compositions dissolve water-soluble dyes having various chemical structures in water and / or a mixed solvent of water-soluble organic solvents, and currently various additives are added as necessary. It is mainly used and commercialized.

[0007]

When a full-color recorded image is reproduced using an aqueous dye ink, four primary color inks obtained by adding black ink to three primary color inks of yellow ink, magenta ink and cyan ink are used. And the color tone of the recorded image is determined by mixing these decolored colors. These inks have one of the performances of the ink described above.
In order to provide a recorded image with a clear color tone, ideal yellow (Y), magenta (M), cyan (C), and black (B
It is also required to exhibit the primary color of k).

However, even the aqueous dye ink composition thus produced is not sufficient in terms of the color balance of each color of yellow (Y), magenta (M), and cyan (C) and the sharpness of the printed matter. Various improvements are being considered, but not enough. In particular, magenta often has a color close to red (R).

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides an aqueous magenta ink for recording which is excellent in liquid stability, has a good color tone as magenta of recorded matter, and is vivid. It is an object of the present invention to provide an ink jet recording method which is excellent in liquid stability, has a good color tone as magenta of a recorded matter, can perform vivid printing, and does not cause non-discharge and the like.

[0010]

In order to achieve this object, an aqueous magenta ink for recording according to claim 1 is obtained by dissolving a magenta dye in a mixed solvent of water and a water-soluble organic solvent. By using Color Index Number Acid Red 52 as a magenta dye and further containing 2-pyrrolidinone, excellent liquid stability, good color tone as a magenta of a recorded matter, and a vivid recording aqueous magenta ink can be obtained. Can be

Further, the aqueous magenta ink for recording according to claim 2 has excellent liquid stability by setting the content of 2-pyrrolidinone to 5 to 50% by weight based on the total amount of the aqueous magenta ink for recording. Further, it is possible to obtain a recording aqueous magenta ink which has a good color tone as magenta of a recorded matter, enables vivid printing, and has a high fixing speed to a recording material.

Further, in the aqueous magenta ink for recording according to the third aspect, the content of the color index number acid red 52 as a magenta dye is 0.1 to 5% by weight based on the total amount of the aqueous magenta ink for recording. And
Generally, the aqueous dye is used in an amount of 0.1 to 0.5% based on the total amount of the ink composition.
Although the content is 1 to 10% by weight, in the present invention, even when the content of the dye is within the above range, the image recorded on the recording material can obtain a sufficient density and a vivid hue. .

An ink jet recording method for performing recording using the recording aqueous magenta ink according to claim 4 is as follows.
By using the above-mentioned aqueous magenta ink for recording as a magenta ink, an ink jet recording method which is excellent in liquid stability, has a good color tone as magenta of recorded matter, enables vivid printing, and does not cause non-discharge, etc. is achieved. Is done.

[0014]

Embodiments of the present invention will be described below.

The dyes used in the present invention include:
The color index number Acid Red 52, which is a water-soluble acid dye, is essential. This dye has a more vivid color than other acid dyes and direct dyes, and has a good color tone as magenta. Generally, a water-soluble dye is used in a ratio of about 0.1 to 10% by weight in a conventional ink composition, but in the present invention, about 0.1 to 10% by weight is used.
Even with 1 to 5% by weight, sufficient color depth and vividness of the recorded matter can be obtained. Further, other magenta dyes may be added as necessary.

The solvent used in the present invention is a mixed solvent of water and a water-soluble organic solvent. The water-soluble organic solvent mainly has an effect of preventing drying of the ink. Generally, polyhydric alcohols are often used as such an organic solvent, but the water-soluble organic solvent used in the present invention essentially includes 2-pyrrolidinone. The content of the 2-pyrrolidinone in the ink composition is limited to the range of 5 to 50% by weight based on the total weight of the ink. 5
If the amount is less than 50% by weight, the effect of preventing the ink from drying is not exhibited. If the amount is more than 50% by weight, the ink penetrates into the recording paper at a low speed, and often causes a problem in the drying time on the recording paper. Further, the viscosity of the ink composition becomes unnecessarily high, and adverse effects such as difficulty in jetting from the ink jet head occur. Further, other water-soluble organic solvents may be added as necessary.

As the water, it is desirable to use deionized water instead of general water containing various ions.
The content of water in the ink composition depends on the type of the solvent component,
It is determined in a wide range depending on its composition or desired properties of the ink, but is generally 10 to 95% by weight, preferably 10 to 70% by weight, more preferably 20 to 70% by weight based on the total weight of the ink. % By weight.

The basic composition of the ink composition according to the present invention is as described above. Other conventionally known various additives, such as a dispersant, a surfactant, a viscosity adjuster, a surface tension adjuster, a pH adjuster, a protective agent, and the like. Fungicides and the like can be added as needed. For example, polyvinyl alcohol, celluloses, viscosity modifiers such as water-soluble resins, cations, anions,
Nonionic surfactants, pH adjusters such as diethanolamine and triethanolamine. When preparing an ink composition used in an ink jet recording method of charging a recording liquid, a specific resistance adjusting agent such as an inorganic salt such as ammonium chloride is added.

Next, examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1 Color Index Number Acid Red 52 (2 parts by weight) and 2-pyrrolidinone (5 parts by weight) were added to pure water (93 parts by weight), and the mixture was stirred for 30 minutes, and then the mixture was stirred for 30 minutes.
The solution was filtered through a 7 μm membrane filter to obtain a magenta ink composition.

The following (1) to (1) are used for this ink composition.
As a result of the examination of (4), good results were obtained in each case.

(1) Liquid stability: Even after the ink composition was sealed in a heat-resistant glass bottle and stored at -30 ° C. and 60 ° C. for 6 months, no precipitation of insoluble components was observed, and the physical properties and color tone of the liquid were hardly observed. There was no change.

(2) Discharge stability: JP-A-2-15035
Using a shear mode type ink jet head disclosed in Japanese Patent Application Publication No. 5 (1993) -105, continuous ejection was performed for 24 hours at each of the ambient temperatures of 5 ° C., 20 ° C., and 40 ° C. The quality was recorded.

(3) Discharge response;
The intermittent ejection for one minute and the ejection after standing for two months were examined using a shear mode type ink jet head disclosed in Japanese Patent Application Publication No. 5 (1993) -105, and in each case, the tip of the head of the ink jet printer and the ink flow path were examined. The recording was stable and uniform without clogging.

(4) Quality of recorded image: The image recorded on the recording material shown below was high in density, sharp, and a magenta color having a good color tone was obtained.

[0027] Recording material; high-quality paper "Xerox 4024" manufactured by Xerox Co., Ltd. Fine paper "Seven Star" manufactured by Hokuetsu Paper Co., Ltd. Medium-sized paper "Shiro Botan" manufactured by Honshu Paper Co., Ltd. "Toyo filter paper No4".

Example 2 A magenta ink composition was prepared in the same manner as in Example 1 except that the amount of 2-pyrrolidinone added was 50% by weight, and the same experiment was carried out. In each case, excellent results were obtained as in Example 1. .

Comparative Example 1 In Example 1, a magenta ink composition was prepared without using 2-pyrrolidinone, and the same experiment was carried out. As a result, non-discharge of the ink often occurred during the one-minute intermittent discharge of (2) and (3). Was seen. Further, in (3), after leaving for 2 months, clogging occurred at the tip of the head of the ink jet printer, and discharge became impossible. When the surface of the head of the inkjet printer was observed with an optical microscope, it was found that a red substance had adhered.

Comparative Example 2 A magenta ink composition was prepared in the same manner as in Example 1 except that 2-pyrrolidinone was used in an amount of 2 parts by weight, and the same experiment was carried out. Non-discharge was observed. In (3), 2
After standing for a month, clogging occurred at the tip of the head of the ink jet printer, and discharge became impossible. When the surface of the head of the inkjet printer was observed with an optical microscope, it was found that a red substance had adhered.

Comparative Example 3 A magenta ink composition was prepared in the same manner as in Example 1 except that 2-pyrrolidinone was used in an amount of 55 parts by weight, and the same experiment was carried out. Could not be obtained.

Comparative Example 4 In Example 1, a magenta ink composition was prepared using ethylene glycol monomethyl ether instead of 2-pyrrolidinone, and the same experiment was carried out.
In (3), good results were obtained, but in all of the images obtained in (4), the color tone was pinkish and good magenta color was not obtained.

The ink compositions of Examples 1 and 2, which had good ejection stability and ejection responsiveness and good liquid stability, clarity, and color tone, were all used as magenta dyes as Color Index Number Acid Red. Using 52,
Further, it contained 5 to 50% by weight of 2-pyrrolidinone.

On the other hand, Comparative Example 1 in which the ejection stability and ejection response were poor and the liquid stability, sharpness and color tone were poor.
In Nos. To 4, none of the above conditions was satisfied.

[0034]

As is apparent from the above description, the aqueous magenta ink for recording according to claim 1 uses Color Index Number Acid Red 52 as a magenta dye, and 2-pyrrolidinone as a water-soluble organic solvent. By containing, a liquid magenta ink having excellent liquid stability, good color tone as a magenta of a recorded matter, and vivid recording can be obtained.

The aqueous magenta ink for recording according to claim 2 has excellent liquid stability by setting the content of 2-pyrrolidinone to 5 to 50% by weight based on the total amount of the aqueous magenta ink for recording. Further, it is possible to obtain a recording aqueous magenta ink which has a good color tone as magenta of a recorded matter, enables vivid printing, and has a high fixing speed to a recording material.

Further, in the aqueous magenta ink for recording according to the third aspect, the content of the color index number acid red 52 as a magenta dye is 0.1 to 5% by weight based on the total amount of the aqueous magenta ink for recording. And
Generally, the aqueous dye is used in an amount of 0.
Although the content is 1 to 10% by weight, in the present invention, even when the content of the dye is within the above range, the image recorded on the recording material can obtain a sufficient density and a vivid hue. .

An ink jet recording method for performing recording using the recording aqueous magenta ink according to claim 4 is as follows.
By using the recording aqueous magenta ink,
An ink jet recording method which is excellent in liquid stability, has good color tone as a magenta of a recorded matter, enables vivid printing, and does not cause non-discharge or the like is achieved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahito Kato 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi Inside (72) Inventor Shunichi Higashiyama 15-1 Naoshiro-cho, Mizuho-ku, Nagoya-city Inside the corporation

Claims (4)

[Claims] 1. A recording aqueous magenta ink comprising a magenta dye dissolved in a mixed solvent of water and a water-soluble organic solvent, wherein a color index number acid red 52 is used as the magenta dye, and further a water-soluble organic solvent is used. 2
-An aqueous magenta ink for recording characterized by containing pyrrolidinone. 2. The aqueous magenta ink for recording according to claim 1, wherein the content of 2-pyrrolidinone is 5 to 50% by weight based on the total amount of the aqueous magenta ink for recording. 3. The aqueous magenta ink for recording according to claim 1, wherein the content of the magenta dye is 0.1 to 5% by weight based on the total amount of the aqueous magenta ink for recording. 4. An ink jet recording method for recording on a recording material by discharging ink droplets from a discharge port in accordance with a recording signal, wherein the ink is a recording medium according to any one of claims 1 to 3. An ink jet recording method, which is a magenta ink.