JPS58176265A - Recording liquid - Google Patents

Abstract

PURPOSE:To provide a recording liq. giving a recording head prolonged service life, excellent in recording stability over a long term, and well suited for writing utensils and ink jet recording, by incorporating a particular compd. CONSTITUTION:In a liq. medium component comprising water alone or together with 5-95wt% water-sol. org. solvent (e.g., diethylene glycol), 0.5-20wt% compd. of the formula (wherein Q1, Q2 are phenyl or naphthyl optionally substd. by an arbitrary substituent; rings A, B may be substd. by an arbitrary substituent wherein at least either one of them is substd. by one or more of substituents selected from the group consisting of OH, SO3M, COOM, and NRR'; M is a base selected from alkali metal, ammonium, and amines; R, R' are H, optionally substd. alkyl or phenyl) and, if necessary, additives such as a viscosity modifier, surface tension adjustor, pH adjustor, specific resistance adjustor, water retention improver, etc. are dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a recording liquid suitable for use in an inkjet method that performs recording by flying droplets from an orifice of a writing instrument or a recording head, and an inkjet method that uses thermal energy in the back. O Regarding writing instruments (fountain silver, felt-tip pens, etc.) that record on recording materials such as paper, ink made by dissolving various dyes in water or other solvents has traditionally been used. 〇Also, in the inkjet method, various dyes are mixed with water or organic solvents, where recording is performed by discharging the liquid in the recording head due to vibrations caused by piezoelectric vibrators or electrostatic attraction caused by high voltage application bottles. It is known to use ink dissolved in water, etc.＠However, compared to ink for general stationery, inkjet ink requires more stringent conditions in terms of many characteristics.◎ Inkjet recording method It generates little noise and can perform high-speed recording or color recording without requiring special fixing treatment for one plain paper, and various types are being actively researched. .

In this type of recording method, the characteristics of the ink used are that the physical properties such as viscosity and surface tension are within appropriate ranges, and that the melting stability of the dissolved material is high and that it does not clog the fine orifice. , it is required to provide a recording image of sufficiently high density, and that physical property values do not change or solid content precipitates during storage. In addition to the above characteristics, there are no restrictions on the type of recording material. high fixing speed, water resistance, solvent resistance (%
It is also required to have properties such as being excellent in alcohol resistance, light resistance, abrasion resistance, and providing an image with an excellent 1% image resolution.

Among the inkjet recording methods, for example, JP-A-54-5
The method disclosed in No. 1837 is different from other methods in that the driving force for ejecting droplets is obtained by applying thermal energy. Thermal energy is generated in the recording head in response to the recording signal number, and bubbles are generated in the recording liquid that is affected by the thermal energy.

Growth and disappearance occur instantaneously, and the accompanying change in the pressure energy of the recording liquid causes droplets to fly from the orifice at the tip of the recording head to perform recording. In addition to the fact that this recording method is extremely effective for so-called on-demand recording, the recording head section is made with high-density multi-orifices, and P-ray line type recording operation can be easily realized, resulting in high resolution. It has the advantage of being able to quickly obtain paintings.

However, in this recording method, thermal energy is directly applied to the recording liquid volume, and the temperature instantaneously reaches over 250 DEG C., especially in the bubble generating area. Therefore, in addition to the above-mentioned general inkjet ink properties, recording liquid properties that satisfy continuous recording performance over a long period of time or ejection stability after a long period of recording stoppage are required, especially thermal dissolution stability. Other characteristics such as not clogging the orifice and not thermally changing the color tone of the ink are also required. However, a recording liquid that satisfies all of these characteristics has not been known so far.

An object of the present invention is to provide a recording liquid for writing instruments such as felt-tip pens and for inkjet recording.

Another object of the present invention is to provide a recording liquid for inkjet recording that utilizes thermal energy, which extends the life of a recording head and has high recording stability over a long period of time.

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

That is, the present invention is a recording liquid characterized by containing a compound represented by the following general formula.

However, in the formula, Ql and O2 each represent a phenol or naphthyl group substituted with or unsubstituted with any substituent, and benzene IJA and naphthalene ring B may be substituted with any substituent, but at least one of them is O.
Represents a benzene ring or naphthalene term substituted with at least one substituent of H group, 803M group, C00M group and NRR' group, where M represents a base selected from alkali gold, ammonium and amines, and R and R' each independently represent hydrogen or an optionally substituted alkyl or phenyl group.

Among the compounds represented by the above general formula, preferred compounds have at least one OH group, 503M group, C0
It has 0M group or NF2 group. Also Q,
And as O2, halogen atom, OH group, 503M
group, Co0M group, NF2 group, NHCO (alkyl) group, NO□ group, phenyl or naphthyl group substituted or unsubstituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms is preferred. Preferred substituents for benzene iA and naphthalene 1B (7) include halogen atom, OH group, 803M group, Co0M
group, NRR' group, NO2 group, alkyl group having 1 to 4 carbon atoms, and alkoxy group having 1 to 4 carbon atoms.

A more preferred compound is one in which the naphthalene ring B has an OH group at the 1st position, an 803M group at the 3rd position, and a Q2 group at the 6th or 7th position via an amide bond.

The compound (dye) of the general formula contained in the recording liquid of the present invention generally has a solubility of 10% by weight or more in the recording liquid medium, and is stable at low temperatures (about -30°C). There is an azo bond (-N=
N-), so even if the recording liquid is momentarily exposed to high temperatures exceeding 250°C in the heat-acting part of the recording head and the compound decomposes, the cleavage will occur mainly at this azo bond. Presumed. Even if decomposition occurs, the q) decomposition products themselves from the compound are relatively stable, and many of them have highly hydrophilic groups such as 803M groups or OH groups; It has high solubility in recording liquid. Therefore, even during continuous recording over a long period of time, stable recording is possible without forming deposits inside the recording head. Of course, the other properties required for writing instruments or inkjet ink dyes, such as weather resistance, ozone resistance, water resistance of printed materials, alcohol resistance, and toxicity, are also sufficient. Specific examples of the compound of the general formula contained in the recording liquid of the invention include dyes having the following chemical structures.

15! Da 5! Da D
Lotto
ω5! Da 5!
Da. : 5! The base that binds with the sulfonic acid group of these compounds to form a sulfonate is - More specifically, N1% to %L1
, Cm, quaternary ammonium cations such as +NI(4-NH(CIH40H)8), and amines such as N(CmH*)m. However, it is usually 0.5 to 20% by weight, preferably 0.5 to 1% by weight based on the amount of recording liquid.
It is used at a concentration of 5 wt.wt., more preferably 1-10 wt.wt. Of course, the dyes can be used alone or in combination of two or more, or in combination with various dyes such as other direct dyes and acid dyes. The liquid medium components for composing the recording liquid are as follows:
Various kinds of water or water-soluble are available! Mixtures with solvents are used as 0 water-soluble organic solvents f! , N, /f
alcohol, ethyl alcohol, u-7'' propyl alcohol, inpropyl alcohol, +a-fetreal alcohol, Hatake/c-butyl alcohol start
- Alkyl alcohols having 1 to 4 carbon atoms such as butyl alcohol and isobutyl alcohol; Amides such as dimethylformamide and dimethylacetamide; Ketones or ketone alcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane
: Nitrogen-containing heterocyclic ketones such as N-methyl-2-pyrrolidone and l,3-dimethyl-2-imidazolidinone;
Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol,
10 Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as pyrene glycol, butylene glycol, triethylene glycol, 1,2,6-hexandriol, thiodiglycol, hexylene glycol 1 diethylene glycol; Glycerin; ethylene glycol methyl ether, diethylene glycol methyl (
or lower alkyl ethers of polyhydric alcohols such as ethyl) ether and triethylene glycol monomethyl (or ethyl) ether.

Among these many water-soluble organic solvents, diethylene glycol, which is a polyhydric alcohol, and triethylene glycol monomethyl (or ethyl) ether, which is a lower alkyl ether of a polyhydric alcohol, are preferred.

The content of the water-soluble organic solvent in the recording liquid is generally in the range of 5 to 95% by weight, preferably 10 to 80%, more preferably 20 to 50% based on the total weight of the recording liquid. Ru.

The recording liquid of the present invention prepared from such components is also described below.
As a recording liquid for inkjet recording or so-called inkjet recording, it has excellent recording properties ((No. 11 response, droplet formation stability, ejection stability, long-term continuous recording, long-term recording suspension). Post-discharge stability) Excellent, well-balanced storage stability, recording agent dissolution stability, fixation to recording material, original durability of recorded images, weather resistance, water resistance, alcohol resistance, etc. In order to further improve these characteristics, it is possible to add one or more of the various additives known in the past.

Such additives include, for example, viscosity modifiers such as polyvinyl alcohol, cellulose, and water-soluble resins; cationic, anionic, or nonionic ellipsoidal surfactants; surface tension modifiers such as jetanolamine and triethanolamine. Agents: Examples include PR adjusting agents using adjuvants.

In order to prepare a recording liquid used in a type of recording method in which the recording liquid is charged, a resistivity adjuster such as inorganic salts such as lithium chloride, ammonium chloride, and sodium chloride is used. In addition, urea and thiourea are preferably used as water-retaining agents at the tip of the ejection orifice.In addition, in the case of a type that ejects the recording liquid by the action of thermal energy, thermal physical properties (e.g., specific heat, (thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.

When using the recording liquid of the present invention as a recording liquid for recording devices, it is necessary to adjust the physical property values in consideration of heat, viscosity, compatibility with recording members made of various materials, etc. The invention will be explained in more detail in the following examples.

Example 1 A recording head for inkjet recording in which ink is ejected by the action of thermal energy was prepared as follows. First, 5IOJ (lower layer) was formed on an alumina substrate to a thickness of 5 μm by sputtering, and then a heating resistor layer of HfB 1000 A was laminated to a thickness of aoooX as an electrode, and then a layer of 50 pm was formed by selective etching. A heating resistor pattern of 200 μm was formed. Next 810. After laminating the layer as a protective layer (upper layer) on 3500A rhinoceros by sputtering and forming an electric/thermal converter on the substrate, a width of 50 μm x depth of 50
A glass plate with micrometer grooves cut into it was bonded so that the grooves and the heating resistor met. Subsequently, the orifice end vr1 was polished so that the distance between the tip of the heating resistor and the orifice was 250 μm, thereby producing a recording head.

On the other hand, 1 recording liquid was prepared according to the following formulation using ml of the dye having the above chemical structural formula: 〇 Dye with structure 2 3 parts by weight diethylene glycol 25 1N-methyl-2-pyrrolidone 2oI water
521 The above-mentioned ingredients were thoroughly mixed and dissolved in a container, filtered under pressure through a Teflon filter with a pore size of lμ, and then degassed using a vacuum pump to obtain a recording liquid.

This recording liquid was supplied to the recording head described above, and a continuous printing test was conducted. A rectangular voltage pulse print signal of 10 .mu.cm-40 V was continuously applied to the recording head at a period of 500 .mu.a@c. This cough recording solution (which was sufficiently durable for 1150 hours of continuous recording) Using these recording liquids, a 150-hour continuous printing test similar to '4 Example 1 was carried out.However, the printing eccentricity was determined at a cycle of 350 μ-・C. Table 1 shows the durability time.The durability time is defined as the time when the ink flight becomes unstable and it becomes impossible to record according to the pulse signal.Table 1

Claims (1)

[Claims] A recording liquid characterized by containing a compound represented by the following. However, in the formula, Q and Q2 each represent a phenyl or naphthyl group substituted with or unsubstituted with any substituent; benzene ring A and naphthalene ring B may be substituted with any substituent, but at least one of them is OH
represents a benzene ring or naphthalene ring substituted with at least one substituent of a group, a 503M group, a C00M group, and an NRR' group, where M represents a base selected from alkali metals, ammonium, and amines, and R and R
' each independently represents hydrogen or an optionally substituted alkyl or phenyl group 0