JPS5925844A - Recording liquid - Google Patents

Abstract

PURPOSE:To provide a fuchsine-colored recording liquid of high homogeneity, highly stable for a long period, free from clogging in delivery olifice, suitable for ink-jet system and writing utensils, containing specific water-soluble dye(s) such as C.I.Acid Red 257. CONSTITUTION:The objective recording liquid comprising (A) pref. 1-10wt% of at least one sort of water-soluble dye selected from C.I.Acid Red 257, C.I.Acid Red 143, C.I.Acid Red 186, C.I.Acid Red 57, and C.I.Direct Red 212, (B) 20- 50wt% of a water-soluble organic solvent (pref. diethylene glycol), and (C) water, and, pref., also, (D) a solubilizing agent such as N-methyl-2-pyrrolidone. EFFECT:Having high setting potential, and giving excellent light and water resistance and weatherability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording liquid, particularly a magenta color recording liquid, which is suitable for use in an inkjet system or a writing instrument in which recording is performed by ejecting droplets from an orifice of a recording head.

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 ports (orifices), and must have a clear color tone that is 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.

In addition to these properties, recording can be performed without any restrictions on the type of recording material such as paper, high fixing speed to the recording material, water resistance, solvent resistance (especially 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 inkjet recording is basically composed of a dye as a recording agent and its solvent, so the above recording liquid characteristics are largely influenced by the unique properties of the dye. . Therefore, selecting a dye 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 water and in wetting agents, which are generally organic solvents, is essential for good clogging prevention. and the basics of maintaining the dissolution stability of the recording medium.

On the other hand, when obtaining a full-color recorded image using the inkjet recording method, magenta and yellow are used.

Recording liquids of the three primary colors of cyan or recording liquids of the four primary colors including black are used, and the color tone of the recorded image is determined by subtractive color mixing. In this case, in order to obtain a recorded image with a desired tone, the hue of each of these recording liquids is ideal magenta.

It is required to exhibit a primary color of yellow or cyan 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, the conventionally known magenta recording liquid has the above-mentioned characteristics, especially its solubility.

There are almost no recording liquids that fully satisfy color tone, light resistance, etc., and there has been a strong desire to develop a recording liquid that satisfies these characteristics.

The object of the present invention is to improve solubility in liquid medium components or (
The object of the present invention is to provide a recording liquid that has high long-term dissolution stability and is less likely to cause clogging of an ejection orifice.

Another object of the present invention is to provide a magenta recording liquid for full-color inkjet recording that exhibits an ideal 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 C, I. (Color Index) Acid Red, 257, C01, Acid Red 3, C0 ■. Acid Red Fug Otsu, C0I, Acid Red S7 and C0I, Direct Red, 2/
This is a recording liquid characterized by containing seven or more types selected from the group consisting of , and 2.

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.

Dye as a recording agent of the recording liquid of the present invention, i.e., C,1
, Acid Red, 2. ! i-7, C01, Acid Red Puffer 3, C8■, Acid Red Ig Otsu, C,1,
Acid Red S7 and C0■, Direct Red, 2
/ and 2 are excellent in the above-mentioned important properties as a recording material, such as solubility, color tone as a magenta primary color, and light resistance, and each can be used alone.

Therefore, naturally, more than one of these types can also be used in combination.

The content of these color components, that is, dyes, in the recording liquid is determined depending on the type of liquid medium components, the characteristics required of the recording liquid, etc., but in general, it is determined by θ5-20 based on the total weight of the recording liquid.
The weight ratio is preferably in the range of 0 to 13 weight ratios, more preferably /-IQ weight ratio.

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

Examples of water-soluble organic solvents include methyl alcohol,
Ethyl alcohol, n-7'pyl alcohol, isopropyl alcohol, n-butyl alcohol, 5fllC
- Alkyl alcohols with a carbon number of -4 such as butyl alcohol, tert-butyl alcohol, and isobutyl alcohol Amides such as dimethylformamide and dimethylacetamide Ketones 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 glycol, butylene glycol, triethylene glycol, /, u,
- Alkylene glycols in which the alkylene group contains 1 to 2 carbon atoms, such as hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol:
Glycerin: ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, 1-
Examples include lower argyl 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 triethylene glycol monomethyl (or ethyl) ether are preferred. Polyhydric alcohols are particularly preferred because they are highly effective as wetting agents to 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 S to 9% by weight based on the total weight of the recording liquid, preferably 10 to gθ, and more preferably 20 to 0. The range of

The water content at this time is determined within a wide range depending on the type of the solvent component, its composition, and the desired properties of the recording liquid, but is generally 10 to 9θ relative to the total weight of the recording liquid. Preferably between 10 and 70, more preferably between 20 and 7.
It is considered to be within the range of 0.

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-pyrrolidone, /.

3-dimethyl-niimidazolidinone and the like are preferably used.

The recording liquid of the present invention prepared from such components has excellent recording properties (signal response, stability of single droplet formation, ejection stability, long-term continuous recording, and long-term recording cessation). Ejection stability) Storage stability, fixation to recording material, or light resistance and weather resistance of recorded images.

It has excellent water resistance and is well-balanced. In order to further improve such properties, various conventionally known additives may be added.

Examples: Viscosity modifiers such as EVA, hollyhinyl alcohol, celluloses, and water-soluble resins; Various cationic, anionic, or nonionic surfactants; Surface tension modifiers such as jetanolamine and triethanolamine; H
Adjusting agents and the like can be mentioned.

However, a resistivity adjuster such as an inorganic salt such as lithium chloride, ammonium chloride, or sodium chloride is added to the preparation of a recording liquid used in an inkjet recording method in which the recording liquid is charged.

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 with conventional writing instruments such as fountain pens and felt-tip pens that record on recording materials such as paper. It can also be used as a liquid.

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

Example 1 A magenta primary color recording liquid for inkjet recording was prepared according to the following formulation.

C0■, acid red 2 left 7. 2.5 weight ratio diethylene glycol 300 N-methylnypyrrolidone /3. Q rr ion exchange water
Remaining amount The above-mentioned ingredients are stirred in a container to uniformly mix and dissolve, and then the pore size is 0. l! , &μ fluoropore filter, and was further degassed to obtain a recording liquid.

This recording liquid is ejected by an on-demand inkjet recording head using a piezo vibrator (discharge orifice diameter SOμ, piezo vibrator drive voltage 60■, frequency 11K).
Using a recording device having I(Z), the ejection stability was investigated. As a result, each qg was measured at room temperature (2/'O) and in an atmosphere of 30% humidity.
Good ejection stability was maintained in both continuous ejection for an hour and intermittent ejection for 2 hours.

On the other hand, the long-term storage stability of the recording liquid was investigated using 0C13θ0z.
IrO'a was used for each year, but no problems such as precipitation of the recording material or discoloration occurred.

Furthermore, the color tone of the printed matter was a clear and bright ideal magenta color, and the printed matter was sufficiently legible even after the SO hour irradiation test using a xenon fade meter, and its light resistance was also good.

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

CJ, Acid Red /'13 3.0 Weight coefficient diethylene glycol / 0 〃z3-dimethyl-imidazolidinone / left 0 〃Polyethylene glycol (300) 130 〃Ion exchange water Remaining amount On the other hand, yellow primary color recording liquid,
A cyan primary color recording liquid and a black recording liquid were prepared in the same manner as in Section 2.

However, instead of 'I C01, Acid Red Puffer 3,
For yellow primary color recording liquid, C1■, acid yellow, 2
For the cyan primary color recording liquid, 3 parts by weight of each of C0■ and Direct Blue g B were mixed, and for the black recording liquid, 3 parts by weight of CJ and Direct Black/9 were mixed.

On-demand type multi-head (discharge orifice diameter 3 Sμ, heating resistor resistance value/SOΩ, drive voltage 30μ) that prints by applying thermal energy to the recording liquid in the recording head to generate droplets. , frequency, 21(I
-Tz), and a color printing test was conducted. Regarding the discharge stability, stable discharge was maintained in all cases under the same conditions as in Example. The images obtained were also full-color images with the desired color tone, and each recording liquid was evaluated to be excellent as a primary color liquid for subtractive color mixing. Furthermore, the prints were legible even after the light test, which was the same as in Example.

Examples 3 to 7 Magenta primary color recording liquids were prepared in the same manner as in Example 1, except that the beam side and the amount shown in Table 1 were used instead of C0■, acid red, and tsq. 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 Example 1, and all were good, making them excellent as recording liquids for magenta primary color. It has been found.

Table -l

Claims (1)

[Claims] 1 Consists of a liquid composition containing a water-soluble dye as a recording agent,
The dye is C8■, acid red,! 7, C0I
, Acid Red/113, C0■, Acid Red/
A recording liquid characterized by being one or more selected from the group consisting of G, C0, Acid Red Tough, CJ, Direct Red, and 212.