JPS5925849A - Recording liquid - Google Patents

Abstract

PURPOSE:To provide a fuchsine-colored recording liquid of high homogeneity and light resistance, highly stable for a long period, virtually free from clogging in delivery olifice, for use in ink-jet recording, comprising specific water-soluble dyes such as C.I. Acid Red 35 and 143. CONSTITUTION:The objective recording liquid comprising, as water-soluble dyes, (A) at least one sort of dye selected from C.I. Acid Red 35, C.I. Acid Red 50, C.I. Acid Red 49, C.I. Acid Red 106, C.I. Acid Red 289, C.I. Acid Red 303, C.I. Acid Red 318, and C.I. Acid Red 128, and (B) at least one sort of dye selected from C.I. Acid Red 143, C.I. Acid Red 186, C.I. Acid Red 57, C.I. Acid Red 82, C.I. Acid Red 261, C.I. Acid Red 1, and C.I. Direct Red 212.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording liquid, particularly a magenta color recording liquid, suitable for use in an inkjet system for recording by flying or a writing instrument.

Various types of inkjet recording methods are being actively researched because they generate less noise and can perform high-speed recording on plain paper without requiring special fixing. The recording liquid used in these inkjet recording methods must have physical properties such as viscosity and surface tension within appropriate ranges, must not clog the fine ejection openings (orifices), and must have a clear color tone and be sufficient. It is required to have certain characteristics such as providing a recorded image with a high density and not causing changes in physical properties or precipitation of solid content during storage.

Furthermore, in addition to these characteristics, recording can be performed without limiting the type of recording material such as paper, fast fixing speed to recording material, water resistance, solvent resistance (% alcohol resistance) It is also required to have properties such as excellent light resistance, abrasion resistance, and the ability to provide images with excellent resolution.

The recording liquid used in the inkjet recording method is basically composed of a dye as a recording agent and its solvent, so the characteristics of the recording liquid described above are largely influenced by the inherent properties of the dye. .

Therefore, selecting all the dyes so that the recording liquid has the above characteristics is an extremely important technique in this technical field.

In particular, the solubility of the recording liquid in the liquid medium is important, and having sufficient solubility in both water and wetting agents, which are generally soluble organic solvents, is essential for good clogging prevention. This is the basis for maintaining the properties and dissolution stability of the recording medium.

On the other hand, when obtaining a full-color recorded image using the inkjet recording method, recording liquids of the three primary colors of magenta, yellow, and cyan, or recording liquids of the four primary colors with black added thereto, are used, and the recorded image is created by subtractive mixing of these four primary colors. The color tone is determined. In this case, in order to obtain a recorded image with a desired tone, it is required that the hues of these recording liquids exhibit ideal primary colors of magenta, yellow, or cyan, respectively, and have high chroma. Therefore, it is an extremely important technique to select a dye in consideration of the color tone exhibited by the recording liquid.

However, with regard to conventionally known magenta recording liquids, there are almost none that fully satisfy the above characteristics, especially solubility, color tone, light resistance, etc., and it is difficult to develop a recording liquid that satisfies these characteristics. I was very hopeful.

It is an object of the present invention to provide a recording liquid that has high solubility in liquid medium components or long-term dissolution stability, and is unlikely to cause clogging of an ejection orifice. An object of the present invention is to provide a magenta recording liquid for full-color inkjet recording, which exhibits a bright magenta color and has excellent light resistance.

The above and other objects are achieved by the invention as follows.

That is, the present invention comprises a liquid composition containing a water-soluble dye as a recording agent, and the dye is (a) C, I.

(Color Index) Acid Red 3. S, C,
I.

Acid Red Sθ, C, 1, Acid Red '79,
C.I.

Ants Dred/θ Otsu, C, 1, Acid Red, 2g
7 or more selected from the group consisting of 9, C, 1, Acid Red 3θ3, C, 1, Acid Red 3/g and C, 1, Acid Red/, 2 g (hereinafter abbreviated as group (a)),
C.I.

Acid Red/'13. C, 1, Acid Red Fug B, C, 1, Acid S7, C, I. Acid Red G Ku C, I.

Acid Red 3 Otsu/, C0 ■, Acid Red/ and C, T, Direct Red, 2/,! The group consisting of (
This is a recording liquid characterized by the combination of seven or more types selected from group (b) hereinafter).

According to the present invention, the viscosity, surface tension, etc. are within appropriate ranges,
It does not clog the fine orifice, provides recorded images with sufficiently high density, does not cause changes in physical properties or precipitation of solids during storage, and can record on various materials without limiting the type of recording material. A recording liquid can be obtained which can provide images with a high fixing speed, excellent water resistance, light resistance, abrasion resistance, and resolution.

The group (a) dyes used as recording agents in the recording liquid of the present invention are all excellent in the above-mentioned important properties as recording agents, such as solubility and color tone as a magenta primary color, but they have poor light resistance. There are some drawbacks on the surface, and these dyes alone are problematic as recording agents for recording liquids. On the other hand, group (b) dyes are all excellent in important properties such as solubility and light resistance, but they have some drawbacks in terms of tone as a magenta primary color, and these dyes alone cannot be used as recording materials. It's very appropriate. Therefore, in the present invention, by using two types of dyes in group (a) together with one or more dyes in group (b), the weak points of the dyes in each group can be reinforced and the recording material can be used as a recording material. The aptitude has been obtained.

The content of these color components in the recording liquid, that is, the total dye content of groups (a) and (b), is determined depending on the type of liquid medium components, the characteristics required of the recording liquid, etc. Generally, θj−! with respect to the total amount of recording liquid! θ weight crack, preferably 65
~7.5% by weight, more preferably /~/θ weight ratio.

In this case, the blending ratio of the 7 or more dyes selected from group (a) and the 7 or more dyes selected from group (b) is determined by the individual dyes selected from each group, Especially (b)
Although the optimum range differs depending on the group of dyes, by blending the dyes in a ratio usually in the range of 5:/ to /:3, an excellent recording liquid can be obtained that compensates for the weaknesses of each dye.

Although the recording liquid of the present invention has water as its main liquid medium component, not only a level but also a mixture of water and various water-soluble organic solvents is preferably used.

Examples of water-soluble organic solvents include methyl alcohol,
Ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n7' ethyl alcohol, see~
Fly/~da alkyl alcohols such as butyl alcohol, tert-methyl alcohol, and imbutyl alcohol Amides such as dimethylformamide and dimethylacetamide Ketone or keto alcohols such as acetone and diacetone alcohol: Tetrahydrofuran, dioxane, etc. Ethers: Polyalkylene glycols such as polyethylene glycol and polypropylene glycol: Ethylene glycol, fluoropylene gelicol,
Pethylene glycol, triethylene glycol, 2. ．．
2. Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol: Glycerin: Ethylene glycol methyl ether, diethylene glycol methyl (also ethyl )ether,
l) Lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether.

Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethyl glycol monomethyl (or ethyl) ether are preferred. Polyhydric alcohols are particularly preferred because they are highly effective as wetting agents that prevent nozzle clogging caused by evaporation of water in the recording liquid and precipitation of the recording agent.

The content of the water-soluble organic solvent in the recording liquid is generally in the range of 5 to 95% by weight based on the total weight of the recording liquid, preferably in the range of /θ to 0%, more preferably in the range of 2θ to jo%. be done.

The water content at this time is determined within a wide range depending on the type of solvent component, its composition, and the desired properties of the recording liquid, but it is generally determined within a range of /θ to nθ with respect to the total weight of the recording liquid. preferably /θ to 7θ, more preferably 20 to γθ
It is considered to be within the range of 弼.

A solubilizer can also be added to the recording liquid of the present invention. Typical solubilizing agents are nitrogen-containing heterocyclic ketones, and their intended action is to dramatically improve the solubility of recording agents in liquid media. For example, N-methyl-3
-pyroIJ)', /3dimethyl-3-imidazolidinone, etc. are preferably used.

The recording liquid of the present invention prepared from such components has excellent recording properties (signal response, stability of droplet formation, ejection stability, long-term continuous recording, and long-term recording cessation). Discharge stability) Storage stability, fixation to recording materials, light resistance, weather resistance, water resistance of recorded images, etc. are all well-balanced and excellent0, and these characteristics are further improved. For this purpose, various conventionally known additives may be further added and contained.

flJ Eva, polyvinyl alcohol, cellulose,
Examples include viscosity modifiers for water-soluble resins, etc.: various cationic, anionic or nonionic surfactants, surface tension modifiers such as jetanolamine and triethanolamine, and PH modifiers using buffer solutions.

Further, in order to prepare a recording liquid used in an inkjet recording method of the type in which the recording liquid is charged, a resistivity adjuster such as inorganic salts such as lithium chloride, ammonium chloride, and sodium chloride is added.

Note that when applied to an inkjet system in which recording liquid is ejected by the action of thermal energy, thermal physical property values (eg, specific heat, coefficient of thermal expansion, thermal conductivity, etc.) may be adjusted.

The recording liquid of the present invention has particularly excellent properties as a recording liquid for inkjet recording, but it can also be used for recording on recording materials such as paper, and for conventional writing instruments such as felt-tip pens. It can also be used as a recording liquid.

The invention will be explained in more detail in the following examples.

Example/ A magenta primary color recording liquid for inkjet recording was prepared according to the following formulation.

C, 1, Acid Red 33 10 Weight Section C,
1, Acid Red g, 2/θ 〃Diethylene glycol 3θθ 〃N-Methyl-2-pyrrolidone
/jθ 〃Ion-exchanged water Remaining amount The above ingredients are stirred in a container, mixed and dissolved uniformly, and then filtered through a fluoropore filter with a pore size of θ and jμ, and further degassed to form a recording liquid. did.

This recording liquid is ejected by an on-demand inkjet recording head using a piezo vibrator (discharge orifice diameter jθμ, piezo vibrator drive voltage OθV, frequency KHz).
), the ejection stability was investigated using a recording device having the following. As a result, room temperature (27℃), 5℃, θ℃
Good ejection stability was maintained in both continuous ejection for 1 g hours and intermittent ejection for 2y hours in an atmosphere of , O θ° C. (humidity 30%).

On the other hand, the long-term storage stability of the recording liquid was investigated at θ℃, 3θc,
The test was carried out at 1.0° C. for a year each, but no problems such as recording agent precipitation or discoloration occurred.

The color tone of the printed matter was a clear and bright ideal magenta color, and even after a 59-hour irradiation test using a xenon fade meter, the printed matter was sufficiently legible and had good light resistance.

Example! A magenta primary color recording liquid was prepared in the same manner as in Example 1 based on the following formulation.

C, 1, acid red Sθ /θ weight ratio c
, r, Assidredokotsu/, 2.0 〃Diethylene glycol /jθ 〃/, 3-dimethyl-2-
Imidazolidinone/3θ〃Polyethylene glycol (3θθ)/3θ〃Ion-exchanged water Residue On the other hand, a yellow primary color recording liquid, a cyan primary color recording liquid, and a black recording liquid were prepared in the same manner as above.

However, if yellow primary color recording liquid is used instead of C,1, Acid Red jθ and C,1, Acid Red 26/, C,
1, Acid Yellow, and 23 were blended into C, 1, and Direct Blue for the cyan primary color recording liquid, and 3 parts by weight each of C, 1, and Direct Black/9f for the black recording liquid.

These recording 'e' are performed using an on-demand type multi-head (discharge orifice diameter 35μ, heating resistor resistance value/SθΩ, drive voltage 3θ■1 frequency, 2K
A color printing test was conducted by supplying the sample to a recording device having a high frequency (Hz). Regarding the ejection stability, stable ejection was maintained in all cases under the same conditions as in Examples. In addition, the obtained image is also a full-color image in which a predetermined color tone has been found,
It was evaluated that each recording liquid was excellent as a primary color liquid for subtractive color mixing.Furthermore, the prints were legible even after the same light fastness test as in Example.

Examples 3-2/Magenta was produced in the same manner as in Example/, except that C,1, Acid Red 3S and C,1, Acid Red g,2 were replaced with the dyes shown in Table -/ and the amounts thereof. A primary color recording liquid was prepared. These recording liquids were evaluated for ejection stability, long-term storage stability, color tone of printed matter, and light resistance in the same manner as in Examples, and all of them were good, making them acceptable as recording liquids for magenta primary color. It turned out that

Table/Note) A-R means C, T, 7'/Red, and DR means C, 1, Direct Red.

1/S- 351-

Claims (1)

[Claims] / Consists of a liquid composition containing a water-soluble dye as a recording agent, wherein the dye includes (a) C, I Acid Red 3j, C,
1, Acid Red jθ, C, L Acid Red &?
, C,1, acid red/θ6. C,1, Acid Red Noke, C,1, Acid Red 303, C,1,
Acid Red 37g and C, 1, Acid Red 7.
7 or more species selected from the group consisting of 2g, (b) c,
r, Acid Red/G 3, C, 1, Acid Red Fg B, C, I. Acid Red 37, C, 1, Acid Red 2, C
, 1, Acid Red 2 Otsu/, C, 1, Acid Red/, and C, 1, Direct Red, 2/, 2.