JPS5925845A - 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 122. 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 122, C.I.Acid Red 161, C.I.Acid Red 249, C.I.Acid Red 254, C.I.Acid Red 265, and C.I.Acid Red 276, (B) 20-50wt% of a water-soluble organic solvent (pref. diethylene glycol), and (C) water, and, pref., also, (D) a solubilizing agent. EFFECT:Having continuous recording ability over a long time and 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 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, and in particular, a recording liquid of a dark magenta color.

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. Various properties are required, such as providing a recorded image with high density and not causing changes in physical properties or precipitation of solid content during storage.

In addition to these characteristics, recording can be performed without limiting the type of recording material represented by paper, high fixing speed to recording material, water resistance, 4 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.

Since the recording liquid used in the inkjet recording method is basically composed of a dye as a recording agent and its solvent, the above-mentioned characteristics of the recording liquid are largely influenced by the inherent 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 both water and a wetting agent, which is generally an organic solvent, 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, 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 also 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 following 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.

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

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 has a color index of C0, (color index) Acid Red L-/, 2.2, C, T, Acid Red L-/, C4. , Acid Red, 2g9, C0
1, Acid Red, 2311, C0I. This recording liquid is characterized by containing seven or more types selected from the group consisting of Acid Reds Otsushio, C0I, Acid Red, and 27 Otsu.

According to the present invention, the viscosity, surface tension, etc. are within appropriate ranges,
It provides recorded images with sufficiently high density without clogging the fine orifice, and allows recording on various materials without restricting the type of recording material without causing changes in physical properties or precipitation of solids during storage. It is possible to obtain a recording liquid that provides images with fast fixing speed, excellent water resistance, light resistance, abrasion resistance, and resolution.

The dye as a recording agent of the recording liquid of the present invention, that is, C0
1,7 SITSU RESOD/, 22, C, I, Acid Red L Otsu/, C, 1, Acid Red, 24t9, C, I,
Acid Red, 2. t&, C0I, Acid Red Uoto and C0■, Acid Red, 27Otsu are all excellent in the important properties mentioned above as recording agents, such as solubility, color tone as a magenta primary color, and light resistance. 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 and drop 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 0% based on the total weight of the recording liquid. ．． ,t
-,20 weight range, preferably 0~/3g weight range, more preferably 1~10 weight range.

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

Examples of water-soluble organic solvents include methyl alcohol,
Ethyl alcohol, n-7' alcohol, isopropyl alcohol, n-jf alcohol, 5eC-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and other alkyl alcohols with a carbon number of ~5, dimethylpolamide, dimethylacetamide Amides such as: Ketones such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; Polyalkylene glycols such as polyethylene glycol and polypropylene glycol:
Algylene glycols in which the alkylene group contains one to two carbon atoms, such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol odiglycol, hexylene glycol, and diethylene glycol: Glycerin: Ethylene glycol methyl ether, diethylene glycol methyl ( Also, examples thereof include lower alkyl ethers of polyhydric alcohols, such as triethylene glycol monomethyl (or ethyl) ether, and triethylene 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 that prevent nozzle clogging caused by evaporation of water in the recording liquid and precipitation of the recording agent.

The content of the above-mentioned water-soluble organic solvent in the recording liquid is generally in the range of 9 to 9% by weight, preferably 10 to 9%, more preferably 20 to 20% by weight, based on the total weight of the recording liquid. It is said that

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 10 to 70, more preferably 2.0 to 70
It is considered to be within the range of 70.

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-neepyrrolidone, l.

3-dimethyl-Ω-imidazolidinone and the like are preferably used.

The recording liquid of the present invention prepared from these various components has recording characteristics (signal response, droplet formation stability, ejection stability, long-term continuous recording performance, ejection after a long recording stop) by itself. Stability) Storage stability, fixability to recording material, light resistance of recorded images, i1 weatherability.

Water resistance etc. are all well-balanced and excellent.

In order to further improve such properties, various conventionally known additives may be added.

For example, viscosity modifiers such as polyvinyl alcohol, celluloses, and water-soluble resins; various cationic, anionic, or nonionic surfactants; surface tension modifiers such as jetanolamine and triethanolamine; PH modifiers using buffer solutions, etc. can be mentioned.

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 as a recording liquid for 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

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.

C, 1, Acid Red/, 2.2 3. ,! ; Heavy weight resin ethylene glycol 300 〃N-methyl-pyrrolidone / 0 〃Ion exchange water
Remaining Amount The above-mentioned ingredients were stirred in a container to be uniformly mixed and dissolved, filtered through a Fluorobor filter with a pore size of 0 g, and further deaerated to obtain a recording liquid.

This recording liquid is ejected by an on-demand inkjet recording head using a piezo vibrator (discharge orifice diameter is 0 μ, piezo vibrator drive voltage is 60 V, frequency is 11 K).
Using a recording device having I(z), the ejection stability was investigated. As a result, room temperature (,2IC), s'c
, tio'o, Otsu Under an atmosphere of 0° C. (humidity 30%), good ejection stability was maintained in both continuous ejection for <tg waiting time and intermittent ejection for 2q hours.

On the other hand, the long-term storage stability of the recording liquid was investigated using 0C130C1.
Testing was carried out at 0C for each Ω year, but no problems such as recording agent precipitation or discoloration occurred.

The color tone of the printed material was a clear, bright, and ideal magenta color, and the printed material was fully legible even after the 0-hour irradiation test using a Gisenon fade meter, and the light resistance was also good. .

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

C, 1, A/D/B/ 3.0 weight ratio diethylene glycol /3. Q //Z3
-Dimethyl-niimidazolidinone /S0 Polyethylene glycol (300) y3.0 Ion-exchanged water Remaining amount 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, instead of C,1, Acid Red/Otsu/, in the yellow primary color recording liquid, C0I, Acid Yellow 23,
CJ for cyan primary color recording liquid. Direct Blue G Otsu,
For the blank recording liquid, 3 parts by weight of each of C0■ and Direct Black/9 were blended.

On-demand type multi-head (discharge orifice diameter 35 μ, heating resistor resistance value/30 Ω, drive voltage 30 ■、Frequency u l4(z
), and a color printing test was conducted. Regarding the ejection stability, stable ejection was maintained in all cases under the same conditions as in Example. Furthermore, the obtained images were also full-color images in which predetermined color tones were expressed, and it was evaluated that each recording liquid was excellent as a primary color liquid for subtractive color mixing. Furthermore, the prints could be read even after the same flash light test as in Example.

Examples 3 to g A magenta primary color recording liquid was prepared in the same manner as in Example 1, except that the dyes shown in Table 1 and their amounts were used in place of C, I, Acid Red/2.2. 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 −/

Claims (1)

[Claims] 1 Consists of a liquid composition containing a water-soluble dye as a recording agent,
The dyes are C, Acid Red/2-2, C0*, Abradred L/, XC, 1, Acid Red, 2 Gua, C0*, Acid Red, 2sti, c. ■. A recording liquid characterized in that it is one or more selected from the group consisting of Acid Red Yu S and C01, and Acid Red Yu 27 O.