JPS62192474A - Recording fluid - Google Patents

Abstract

PURPOSE:To obtain a magenta ink which gives a printed image having excellent resistance to water and light without using any specialty paper or carrying out an after-treatment, by using a specified dye as a recording agent for an ink. CONSTITUTION:This recording fluid contains at least one water-soluble dye of formula I or II. In the formulas, R1, R2, R3 and R4 are each H, -NHCONH2 or (CxH2xO)m(CyH2yO)nH (wherein x is 1-4, y is 1-4, m is 1-5 and n is 0-4); R1 and R2 may form a morpholino group when combined together with a nitrogen atom; R5 is halogen; R6 is H or a 1-2C alkyl group; and R7 is H or COOM (wherein M is an alkali metal, ammonium or an org. amine). The dye is particularly suitable for use as a recording agent of a recording fluid used in an ink jet recording system which is carried out by the action of thermal energy.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a recording liquid (hereinafter referred to as ink) for recording on a recording material such as a sheet of paper or a resin film using an inkjet method or a writing instrument such as a fountain pen or a felt-tip pen. (referred to as ).

(Prior Art) The inkjet recording method forms ink droplets using various ink ejection methods, and performs recording by attaching some or all of them to a recording material such as paper. Inks used in such inkjet recording methods include those in which various water-soluble dyes or pigments are dissolved or dispersed in water or a liquid medium consisting of water and a water-soluble organic solvent. has been done.

Further, inks similar to those described above are also used as inks for writing instruments such as fountain pens, felt pens, and ballpoint pens.

(Problem to be solved by the invention) It is natural that conventional inks such as those mentioned above are required to have various performances, but the stability of recorded images, especially water resistance and light resistance, are particularly important. It's about performance. However, water-soluble dyes that are generally used in inkjet inks, especially inkjet inks that utilize thermal energy, especially magenta water-soluble dyes, have thermal stability as an ink. Since it is listed as one of the first performance, it is not possible to fully satisfy the image stability such as water resistance and light resistance.Therefore, in order to obtain such water resistance and light resistance, various additives are added to the liquid medium side. In some cases, after recording, a post-processing process is performed in which a film is laminated on the surface of the image. However, such measures require the use of specially designated paper for coaters, or increase running costs, which is one of the reasons that prevents the spread of inkjet methods.

(Problems to be Solved by the Invention) Therefore, the main purpose of water-soluble dyes is to solve the above-mentioned drawbacks of the conventional technology,
To provide a magenta ink capable of producing recorded images with excellent water resistance and light resistance without post-treatment of special paper.

These objects of the present invention were achieved by the inventor's extensive studies and the discovery of a dye suitable for the ink used for this purpose.

(Disclosure of the Invention) That is, the present invention is a recording liquid containing a water-soluble dye, which is characterized by containing at least one kind of water-soluble dye represented by the following general formula (A) or (B). This is a recording liquid.

However, R1, R2, R3, R4 in the above formula are hydrogen atoms, -NHCONH2 or CCx H2!0)ta (Cy H2yO)n H
(!= 1-4, y=1-4, m=1-5, n=0-4
), R1 and R2 may together form a morpholino group with a nitrogen atom, R5 represents a halogen atom, R6 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R
7 is a hydrogen atom or C00M (M is an alkali metal,
represents ammonium or organic amines).

Next, to explain the present invention in more detail, in order to achieve the above-mentioned object of the present invention, the inventor of the present invention conducted detailed research on dyes, which are recording agent components of ink, and discovered that certain dyes were found in ink. It is suitable as a recording agent, especially for ink used in an inkjet method that uses thermal energy to fly droplets, and by adopting such a specific dye as an ink recording agent, it can be used in an inkjet method. Ink that satisfies the liquid physical properties that match the ejection conditions, long-term storage stability, ink fixability to recording materials, image clarity, high-density images, image light resistance, water resistance, and other required properties. This is what we found out that it can be obtained.

The dye represented by the above general formula (A) or (B) that is used in the present invention and mainly characterizes the present invention may be any dye as long as it is included in the above general formula (A) or (B). However, particularly preferred specific examples include the following.

Specific example 1 Specific example 2 Specific example 4 Specific example 5 Specific example 6 By using the specific dye represented by the general formula (A) or (B) as an ink recording agent, the viscosity and surface Physical properties such as tension are within appropriate ranges, do not clog the fine discharge orifice, provide recorded images with sufficiently high density, and do not cause changes in physical properties or precipitation of solids during storage. It is possible to obtain an ink that can perform recording on various recording materials without limiting the type of material, has a high fixing speed, and provides images with particularly excellent water resistance, light resistance, and resolution.

The content of the above-mentioned dye is determined depending on the type of liquid medium component, the properties required of the ink, etc., but generally it is 0.1 to 20% by weight based on the total weight of the ink.
Preferably 0.5-15%, more preferably 1-10%
The range of

Of course, the dyes can be used alone or in combination of two or more,
Alternatively, the dye may be used as an essential component and various dyes such as other direct dyes and acid dyes may be used in combination.

A suitable solvent for use in the ink of the present invention is water or a mixed solvent of water and a water-soluble organic solvent, and particularly preferred is a mixed solvent of water and a water-soluble organic solvent, which is a water-soluble organic solvent. It contains polyhydric alcohol, which has the effect of preventing ink from drying, as a solvent. Further, as water, it is preferable to use deionized water rather than ordinary water containing various ions. Examples of water-soluble organic solvents used in combination with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol. Alkyl alcohols with 1 to 4 carbon atoms; amides such as dimethylformamide and dimethylacetamide; ketone or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol Class: Alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1゜2.6-hexandriol, thiodiglycol, hexylene glycol, diethylene glycol, etc. Glycerin; Lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) nityl, triethylene glycol monomethyl (or ethyl) ether; N-methyl-2-pyrrolidone, 1 , 3-dimethyl-2-imidazolidinone and the like. 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.

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

The water content at this time is determined within a wide range depending on the type of solvent component, its composition, and the desired characteristics of the ink, but it generally accounts for io to 90% of the total weight of the ink.
, preferably 10-70%2, more preferably 20-70%
%.

The ink of the present invention, which is formulated from such components, has excellent recording properties (signal response, stability of droplet formation, ejection stability, long-term continuous recording, ejection after a long recording pause). Stability) Storage stability, fixability to recording materials, light resistance, weather resistance, water resistance, etc. of recorded images are all well-balanced and excellent. In order to further improve such properties, various conventionally known additives may be further added and contained.

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; and pH adjustment using buffer solutions.
Examples include antifungal agents, antifungal agents, and the like.

In addition, in order to prepare ink used for inkjet methods that charge the ink, lithium chloride,
A resistivity adjuster such as inorganic salts such as ammonium chloride and sodium chloride is added.

Note that when applied to an inkjet system in which ink 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 ink of the present invention as described above is useful as a recording ink for various writing instruments, recording instruments, etc., and is useful as an ink for inkjet use, particularly for inkjet systems in which droplets are ejected using thermal energy.

To explain the inkjet method as an example,
The inkjet method may be any method as long as it can effectively remove the ink from the nozzle and apply the ink to the recording material, which is a projectile. Typical examples of these methods include, for example: IEEE Trans actions on Industry Applications
on Ir+dustry Applic
ations) VoljA-13, No. 1 (1
February/March 977 issue), Nikkei Electronics 197
April 19, 1973 issue, January 29, 1973 issue, 1974
Published in the May 8, 1985 issue and the February 11, 1985 issue. The methods described above are suitable for use with the ink of the present invention.To explain some of them, there is an electrostatic suction method.In this method, a nozzle and an accelerated There is a method in which a strong electric field is applied between the ink particles and the nozzle, and the ink is drawn out one after another from the nozzle, and an information signal is given to the deflection electrodes while the drawn ink flies between the deflection electrodes to record the ink particles. There is a method of ejecting ink droplets in response to an information signal without deflection, and either method is effective for the ink of the present invention.

The second method is to forcibly eject minute ink particles by applying high pressure to the ink with a small pump and mechanically vibrating the nozzle with a crystal oscillator. At the same time as the injection, it is charged according to the information signal. When the charged ink particles pass between the deflection electrode plates, they are deflected according to the amount of charge. Another method using this method is called the microdot inkjet method. In this method, ink pressure and excitation conditions are kept within a certain range of appropriate values, and two types of ink droplets, large and small, are ejected from the nozzle tip. Only small and medium-sized droplets are generated and used for recording. The feature of this method is that it is possible to obtain a group of minute droplets even with a conventionally large nozzle diameter.

A third method is a piezo element method, in which a piezo element is used as a pressure means for applying pressure to the ink, rather than a mechanical means such as a pump as in other methods. This method applies an electric signal to a piezo element to cause mechanical displacement, thereby applying pressure to the ink and ejecting it from a nozzle.

In particular, the ink of the present invention is produced by a method described in Japanese Patent Application Laid-Open No. 54-51837, in which the ink undergoes a rapid volume change when subjected to the action of thermal energy, and the acting force caused by this change in state causes the ink to be drawn into the nozzle. It can be effectively used in an inkjet method in which the ink is ejected from the inkjet method.

Since the ink of the present invention as described above employs a specific dye as its recording agent, it has excellent long-term storage stability and ejection stability, not only as an ink for general recording, but also as an ink for use in inkjet systems in particular. , by having recording characteristics such as ejection responsiveness and being applied to the recording material.

It exhibits excellent ink fixing properties and provides recorded images particularly excellent in light fastness, water resistance, sharpness, resolution, etc.

Next, the present invention will be explained in more detail with reference to Examples. In the text, parts and percentages are based on weight unless otherwise specified.

Example 1 Dye of specific example (1) 4 parts diethylene glycol 25 parts ion exchange water
71 parts The above composition was thoroughly mixed and dissolved in a container, filtered under pressure through a Teflon filter with a pore size of 0.45 gm, and then degassed using a vacuum pump to obtain the ink of the present invention. Using the obtained ink, energy is given to the ink in the recording head to generate droplets to perform recording.On-demand type multi-head (discharge orifice diameter 35gm, heating resistor resistance value 150Ω, drive voltage 3
When the following (TI) to (T5) were investigated using a recording device having a voltage of 0V and a frequency of 2K)1z), good results were obtained in all cases.

(T1) Long-term storage stability of ink: Even after sealing the ink in a plastic film bag and storing it at -30°C and 60°C for 6 months, no precipitation of insoluble matter was observed, and there was no change in the physical properties or color tone of the liquid. There was no.

(T2) Ejection stability: Continuous ejection was performed for 24 hours in an atmosphere of room temperature, 5° C., and 40° C. Under all conditions, stable high-quality recording was possible from beginning to end.

(T3) Ejection response: Intermittent ejection every 2 seconds and ejection after being left for 2 months were investigated, and in both cases, there was no clogging at the orifice tip, and stable and uniform recording was achieved.

(T4) Quality of recorded images: The images recorded on the recording materials shown in the table below had high density and were clear. After being exposed to indoor light for 6 months, the density reduction rate was less than 1%, and when immersed in water for 1 minute, there was very little blurring of the image. (T5) Fixation on various recording materials Quality: After printing on the recording materials shown in the table below, the printed area was rubbed with a finger after 15 seconds, and the presence or absence of image shift and bleeding was determined. All of them have excellent fixing properties with no image shifting or bleeding, and are made of silver-plated high-quality paper.
Yamaba Kokusaku Pulp ■Seven Star Paper Hokuetsu Paper ■White Botanchu Pawn Paper Honshu Paper ■Toyo Roshi No. 4 Non-size Paper Toyo Roki Paper■Example 2 Dye of Example (2) 2 parts diethylene glycol 21 parts N-methyl -2-pyrrolidone 15 parts water
62 copies The ink of the present invention having the above composition was prepared in the same manner as in Example 1, and an on-demand type multi-head (discharge orifice diameter 35
In the same manner as in Example 1, (TI) to (T5) were investigated using a recording device with a heating resistor resistance of 150 Ω, a driving voltage of 30 V, and a frequency of 2 KHz. We obtained the following results.

Example 3 Specific example (4) Dye 5 parts ethylene glycol 20 parts 1,3-dimethyl-
2-imidazolidinone 30 parts water 45
The ink of the present invention having the above composition was prepared in the same manner as in Example 1, and an on-demand type multi-head (discharge orifice diameter: 35 g) that performs recording by applying thermal energy to the ink in the recording head to generate droplets. (T1) to (T5) in the same manner as in Example 1 using a recording device having a heating resistor resistance value of 150 Ω, a driving voltage of 30 V, and a frequency of 2 KHz.
We conducted a study on this, and obtained excellent results in all the study experiments.

Example 4 Specific example (6) Dye 3 parts diethylene glycol 7 parts methyl ether 30 parts Water 67
The ink of the present invention having the above composition was prepared in the same manner as in Example 1, and an on-demand type multi-head (with an ejection orifice diameter of 35 (T1) to (T5) in the same manner as in Example 1 using a recording device having a heating resistor resistance of 150 Ω, a driving voltage of 30 V, and a frequency of 2 KHz).
We conducted a study on this, and obtained excellent results in all the study experiments.

As explained above, by using the ink of the present invention.

(1) The liquid has good long-term storage stability, especially thermal stability,
Less likely to cause clogging of the discharge port.

(2) Stable discharge of 70°C against fluctuations in temperature and driving conditions
- Once is wide.

(3) Fixation on the recording material is fast and the image is clear.

(4) The printed matter has good water resistance and light resistance.

(5) The ink is highly safe and does not attack surrounding materials (container sealing materials, etc.).

There are advantages such as

Claims (2)

[Claims] (1) A recording liquid containing a water-soluble dye, which is characterized by containing at least one type of water-soluble dye represented by the following general formula (A) or (B). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(B) (However, R1, R2, R3, R4 in the above formula are hydrogen atoms, -NHCONH2 or (C_xH2_xO )_m(C_yH2_yO)_nH
(x=1-4, y=1-4, m=1-5, n=0-4)
, R1 and R2 may together form a morpholino group with a nitrogen atom, R5 represents a halogen atom, R6 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R7
represents a hydrogen atom or COOM (M represents an alkali metal, ammonium or organic amine). ) (2) The recording liquid according to claim (1), which is used in an inkjet recording method in which thermal energy is applied.