JPS61101571A - Water based ink - Google Patents

Abstract

PURPOSE:To provide a water based ink useful for ink jet recordings, excellent in clarity and drying properties of images, storage stability, ejection stability, and ejection response, by incorporating a water-soluble dye of a particular formula, a wetting agent, and other additives. CONSTITUTION:The desired water based ink is yielded by incorporating a water soluble dye of the formula (wherein R1, R2 are H, alkyl, alkoxy, halogen, carboxyl, sulfonic group; l is 1, 2; R3, R4 are hydroxyl or optionally substd. amino group; m is 0, 1; M is H, Na, K, Li, cation of org. amines, etc.; n is 1, 2, 3), a wetting agent, and other additives.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates to improved aqueous inks for inkjet recording.

In conventional inkjet recording, in order to perform good recording over a long period of time, the ink used must satisfy the following conditions.

1) Ink physical properties such as ink viscosity, surface tension, specific conductivity, and density must be within appropriate ranges depending on droplet generation method and droplet flight direction control method; 2) Long-term storage, long-term use, or 3) The recorded image must have sufficiently high contrast and clarity; 4) The printed image should dry quickly. thing.

In order to meet the above requirements, it is required that the molecular extinction coefficient of the dye used in the ink is sufficiently high, and that the solubility of the dye in water and a wetting agent is sufficiently high.

Furthermore, the ink used in full-color printers, etc. must 5) exhibit color tone with excellent purity, and 6) the recorded image must be smudge-free with excellent water resistance, light resistance, and wear resistance. Must be a clear image.

The above requirements are satisfied! To date, many proposals have been made for inkjet recording inks, but at present no ink has yet been obtained that fully satisfies all of the above conditions.

The properties required above are particularly influenced by the dyes among the materials used in the ink, and the development of new dyes has been awaited in order to satisfy these requirements.

OBJECTS The present invention aims to provide an ink that satisfies the various conditions required for the above-mentioned conventional inkjet recording inks, and consists in developing a dye particularly suitable for magenta ink.

In order to achieve the above object, the present invention provides an aqueous ink containing a water-soluble dye, a wetting agent, and other additives. Carboxyl group, sulfonic acid group, β=1 or 2 R3, R4: hydroxyl group, unsubstituted or substituted amino group, 1=0 or 1 M; represents a cation such as hydrogen, sodium, potassium, lithium, or organic amine.

It is characterized by using at least one kind of water-soluble dye represented by rv-1, rv-2 or rv-3.

Representative examples of water-soluble dyes used in the present invention are listed below.

These dyes can be easily synthesized by conventional methods. For example, the dye shown in Example 1) can be obtained by tetrazotizing 4,4-diaminodiphenylmethane by a conventional method and then coupling it with N-penzoyl monoacid in an alkaline state.

The ink of the present invention uses water as a solvent component, and water is used for purposes such as adjusting the physical properties of the ink to desired values, preventing drying of the ink, and improving the solubility of dyes. As a wetting agent, the following water-soluble organic solvents and water may be mixed and used.

Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polyhydric alcohols such as glycerin, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol Alkyl ethers of polyhydric alcohols such as monomethyl ether and triethylene glycol monoethyl ether, as well as N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, dimethylformamide, triethanolamine, etc. be.

Among these, particularly preferred are diethylene glycol, polyethylene glycol 200~eoo, triethylene glycol, ethylene glycol, glycerin, N
-Methyl-2- and lolidone, and by using these, it is possible to increase the solubility of the dye and the effect of preventing clogging by preventing moisture evaporation.

The water-soluble organic solvent contained in the ink can be used in an amount of 5 to 80% based on the total weight of the ink, but it is preferably used in an amount of 10 to 40% in view of viscosity, drying properties, etc.

In addition to the dyes and solvents described above, conventionally known dyes and additives can be added to the ink of the present invention.

As preservatives and fungicides, sodium dehydroacetate, sodium rupine acid, ? - Sodium pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, etc. can be used in the present invention.

As the pl-1 regulator, any substance can be used as long as it can control the pH of the ink within the range of 9.0 to 11.0 without adversely affecting the ink being prepared. .

Examples include amines such as jetanolamine and triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, and potassium hydroxide;
Examples include alkali metal v2 salts such as ammonium hydroxide, lithium carbonate, sodium rAate, and potassium carbonate.

Specific electrical conductivity regulators include, for example, potassium chloride,
Examples include inorganic salts such as ammonium chloride, sodium VIJI acid, and sodium carbonate, and water-soluble amines such as triethanolamine.

Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uramildiacetate.

Examples of rust preventives include acidic sulfites, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate,
Examples include dicyclohexylammonium nitrite.

In addition, depending on the purpose, water-soluble ultraviolet absorbers, water-soluble infrared absorbers, water-soluble polymer compounds, dye solubilizers, surfactants, etc. can be added.

Examples and comparative examples of the present invention are shown below, and all percentages are percentages.

Example 1 After heating and stirring the following composition to about 50°C and dissolving it, the pore size was 0.
．． The ink was prepared by filtration through a 22 μm Teflon filter. The physical properties of the ink are as shown in the table.

Dye of specific example (1) 3.0% diethylene glycol 15.0% glycerin
5.0% sodium dehydroacetate 0.1% water 76.
Inks of Examples 2 to 5 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1 except that materials having the following composition were used. The physical properties of these inks are also shown in the table.

Example 2 Taitai 1911 (2) dye 231 3.0% diethylene glycol 15.0% glycerin
5.0% Sodium dehydroacetate
0.1% water
76.9% Example 3 Dye of specific example (3) 3.0% diethylene glycol 15.0% glycerin
5.0% sodium dehydroacetate 0.1% water
16.
9% Example 4 Dye of Specific Example (9) 3.0% Triethylene glycol to,o% 2.2--Thiogetanol 10.0% Sodium benzoate 0.2%
water 76
．． 9% Example 5 Dye of Specific Example (1o) 3.0% Polyethylene Glycol 200 5.0% Triethylene Glycol Monomethyl Ether 15.0% Sodium Benzoate 0.2% Water
16.8% Comparative Example 1 C,1, Acid Red 35 3.0% diethylene glycol 15.0% glycerin
5.0% Sodium dehydroacetate 0.1%
water 76
．． 9% Comparative Example 2 C,1, Acid Red 17 3.0% diethylene glycol 15.0% glycerin
5.0% Sodium dehydroacetate 0.1%
water 76
．． 9% Comparative Example 3 C, 1, Direct Red 37 3.0% diethylene glycol 15.0% glycerin
5.0% Sodium dehydroacetate 0.1%
water 7
Physical properties of 6.9% ink 1 The ink was diluted with pure water to a dye concentration of 1 wt%, applied to high-quality paper with a doctor blade, and air-dried for one day to prepare a sample. After immersing this sample in water at 30°C for 1 minute, the concentration was measured using a Macbeth a meter, and the lIr value before immersion was measured.
compared with l.

A sample prepared in the same manner as Mine 21 was subjected to a fade meter (carbon arc lamp, 63'C) for 3 hours, and the fading rate was determined in the same manner as in 1.

Effects (I) Evaluation tests were conducted on the ink composition of Example 1 on four items. The results are shown below.

1) Image clarity and image dryness: Particle frequency 100 KHz from a nozzle with an inner diameter of 30 μm
When the ink was jet-recorded on commercially available high-quality paper under the following conditions, a clear image without bleeding was obtained. The drying time of the recorded matter was within 10 seconds at room temperature and humidity.

2) Storage: Seal the ink in a glass container and store at -20°C for 1 month, 4
1 month at ℃, 1 year at 20℃, and 1 week at 90℃.
Although both were stored, no precipitation was observed. Further, there were no significant changes in the physical properties or color tone of the ink.

3) Jetting stability: The jet recording described in 1) above was performed continuously for 1000 [times], and stable recording was achieved without clogging the nozzle or changing the jetting direction.

4) Jetting response: After jet recording was performed according to 1) above, the jet was left at room temperature and humidity for one month and at 40°C and 30% RH for one week, and then jet recording was performed again according to 1). As in 3) above, stable recording was possible.

(IF) When the inks of Examples 2 to 5 were tested for jetting response in the same manner as in Example 1, good results were obtained as in Example 1. On the other hand, in the case of Comparative Examples 1 to 3 in (), the temperature was 13+1 at normal temperature and humidity, and 40°C 30%R)
When the ink was left for three days, each nozzle became partially clogged, and the direction of ink jetting became extremely unstable, making jet recording impossible.

Patent Applicant Ricoh Co., Ltd. - Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi Proceedings (spontaneous) December 25, 1980 Commissioner of the Japan Patent Office Manabu Shiga 1, Indication of the case Showa 1959 Patent Application No. 2212
No. 78 No. 2, Title of the invention Water-based ink 3, Relationship with the amended person's case Name of patent applicant (674) Ricoh Co., Ltd. -5,
Date of amendment order (voluntary) 6. Subject of amendment Detailed description of the invention in the specification.

7. Contents of the amendment: As shown in the attached sheet.

/Zurupa,\111 example; 59.12.25 (Attachment) 1. The structural formula of Compound 6 on page 6, line 3 is corrected as follows.

2. Change “Water 16.9%” in the 12th line of the 13th member to “Water
Corrected to 76.8%J.

Claims (1)

[Scope of Claims] A water-based ink characterized by containing a dye of the following general formula, a wetting agent, and other additives. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ R_1, R_2; Hydrogen, alkyl group, alkoxy group, halogen, carboxyl group, sulfonic acid group, l=1 or 2 R_3, R_4; Hydroxyl group, unsubstituted or substituted amino group, m =0 or 1 M; indicates a cation such as hydrogen, sodium, potassium, lithium, or organic amine. n=1, 2 or 3