JPH0778190B2 - Recording liquid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel recording liquid (hereinafter referred to as ink), and in particular, a liquid is ejected from a fine ejection port (ejection orifice) provided in a recording head. The present invention relates to an ink suitable for a method of recording by ejecting as droplets.

(Prior Art) A writing instrument (fountain pen, etc.) for recording on a recording material such as paper from the past.
For example, a felt pen or the like is used as an ink in which various dyes are dissolved in water or other organic solvent.

Further, in a so-called ink jet system in which ink is ejected from an ejection orifice from an ejection orifice to perform recording by vibrating a piezoelectric vibrator or electrostatic attraction by applying a high voltage, various dyes are dissolved in water or an organic solvent. Ink is being used. However, in comparison with general fountain pens and stationery inks such as felt pens, inkjet inks have many characteristics and require stricter conditions.

The ink jet system is a type that produces little noise and can perform high-speed recording or color recording on plain paper without a special fixing process, and various types have been actively studied.

There are various methods of this kind, but in any case, the ink used has a physical property value such as viscosity and surface tension within an appropriate range, and the recording agent has high dissolution stability and a fine ejection orifice. It is required to have various properties such as not causing clogging, providing a recorded image with a sufficiently high density, and preventing changes in physical properties or precipitation of solid contents during storage.

In addition to the above characteristics, recording can be performed without limiting the type of recording member, high fixing speed, water resistance, solvent resistance (especially alcohol resistance), light resistance, abrasion resistance and resolution. Properties such as providing excellent recorded images are also required.

However, a recorded image using a conventional ink, particularly a water-based ink, tends to cause bleeding, blurring, or fading due to water adhesion or light irradiation. This tendency is remarkable especially in magenta recording, and an ink in which these defects are improved is strongly desired.

From this point of view, many proposals have been made regarding inks, but practical inks that satisfy all the above conditions have not been obtained.

Particularly with respect to magenta, almost no known dye has both clear color tone and high light resistance. That is, a dye having a clear color tone such as a xanthate type dye has extremely low light resistance, and a dye having a good light resistance such as a metal-containing azo dye has a defect that the color tone is not sharp.

Therefore, it is an object of the present invention to provide a magenta color ink that satisfies all the above conditions. That is, the purpose of the present invention is to provide an ink having excellent recording properties, ejection stability, and ejection responsiveness without causing clogging of the ejection orifices, deterioration of the ejection orifices or generation of precipitates during storage.

Another object of the present invention is to provide an ink having excellent color tone and contrast of a recorded image. Still another object of the present invention is to provide an ink having a recorded image which is excellent in water resistance, alcohol resistance, light resistance and resolution and which is excellent in fixability.

(Means for Solving Problems) The above object is achieved by the present invention described below.

That is, the present invention provides a dye represented by the following general formula (A) as a recording agent in a recording liquid containing a recording agent which is a component for forming a recorded image and a liquid medium for dissolving or dispersing this recording agent. And at least one kind of dye selected from the group consisting of CI Acid Red 131, CI Acid Red 274, CI Direct Red 227, and CI Direct Red 9.

(However, R ₁ and R ₂ in the above formula represent any substituents, and X
Is a residue of an organic acid, and M represents one kind of base selected from alkali metals, ammonium and organic amines. (Function) In order to achieve the above-mentioned object of the present invention, the present inventor has conducted a detailed study on a dye, which is a recording agent component of ink, particularly a magenta dye. It is suitable as a recording agent, particularly as a recording agent for an ink used in an inkjet method, and by adopting such a specific combination of dyes as a recording agent for an ink, the color tone is extremely clear when used in an inkjet method. It was found that an ink which gives a recorded image satisfying the required performances such as water resistance, light resistance, resolution, alcohol resistance and the like can be obtained.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The dye represented by the above general formula (A) used in the present invention may be any dye as long as it is included in the above general formula (A), and particularly preferable specific examples thereof include the followings. There are things. Although sodium salt is mentioned as an example, it is not limited to sodium salt and may be formed with any base such as lithium salt, potassium salt, ammonium salt, organic amine salt and the like.

Dye (A) as above and CI Acid Red 131, CI
The main feature of the present invention is to use in combination with at least one dye selected from the group consisting of Acid Red 274, CI Acid Red 227 and CI Acid Red 9, and the ink obtained by such a specific combination is It provides a recorded image having excellent color tone sharpness, light resistance, water resistance and the like, which are remarkably excellent as compared with conventional inks of the same color.

The total content of the above dyes is the type of liquid medium component,
It is determined depending on the properties required for the ink, etc., but is generally in the range of 0.1 to 20% by weight, preferably 0.5 to 15%, and more preferably 1 to 10%, relative to the total weight of the ink. To be done. Regarding the amount of these dyes used, the effect of the present invention is most remarkable when the dye (A) is used in a proportion of 20 to 80% by weight, preferably 30 to 70% by weight of the total weight of the dye. To be achieved. Of course, in addition to these specific dyes, various other dyes such as direct dyes and acid dyes can be used in combination.

The solvent suitable 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 preferable is a mixed solvent of water, a water-soluble organic solvent and a water-soluble organic solvent. As a solvent, a polyhydric alcohol having an effect of preventing ink drying is contained. Further, as the water, it is preferable to use deionized water instead of general water containing various ions. Examples of the water-soluble organic solvent used by mixing with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, t
ert-C1 to C4 alkyl alcohols such as butyl alcohol and isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; acetone,
Ketones or keto alcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane;
Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol,
Propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol and other alkylene groups containing 2 to 6 carbon atoms; glycerin; ethylene Lower alkyl ethers of polyhydric alcohols such as glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether and triethylene glycol monomethyl (or ethyl) ether; N-methyl-2-pyrrolidone, 1,3-dimethyl- 2-imidazolidinone etc. are mentioned. 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 preferable.

The content of the water-soluble organic solvent in the ink is generally 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. is there.

The water content at this time is determined in a wide range depending on the kind of the solvent component, its composition or desired properties of the ink, but generally 10 to 95%, preferably 70% by weight of the total ink. % Or more, more preferably 80% or more.

The ink of the present invention prepared from such components has recording characteristics (signal responsiveness, droplet formation stability, ejection stability, long-term continuous recording ability, ejection after a long recording pause) by itself. (Stability) Storage stability, fixability on a recording material, color tone clarity of a recorded image, light resistance, weather resistance, water resistance, alcohol resistance, etc. are well balanced and excellent.
In order to further improve such characteristics, various conventionally known additives may be further added and contained.

For example, viscosity adjusting agents such as polyvinyl alcohol, celluloses and water-soluble resins; various surface-active agents such as chaotic, anionic or nonionic surfactants, diethanolamine and triethanolamine; pH adjusting agents with buffer solutions, antifungal agents. Examples thereof include agents.

Further, in order to prepare an ink used for an ink jet type of charging the ink, a specific resistance adjusting agent such as an inorganic salt such as lithium chloride, ammonium chloride or sodium chloride is added.

When applied to an inkjet system of a type that ejects ink by the action of thermal energy, thermal physical property values (for example, 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 and the like, and is particularly useful as an inkjet ink. The ink jet method may be any method as long as it can effectively separate the ink from the nozzle and apply the ink to the recording material that is a range.

(Effects) The ink of the present invention as described above has excellent long-term storage as an ink for general recording as well as an ink for use in an ink jet system by adopting a combination dye of a specific combination as a recording agent. Has excellent recording properties such as ink resistance, ejection stability, and ejection response, and when applied to a recording material, it exhibits excellent ink fixability, and particularly exhibits color tone description, light resistance, water resistance, alcohol resistance, resolution. And the like, which gives an excellent recorded image.

(Examples) The present invention will be described more specifically with reference to the following examples, comparative examples and usage examples. In the text, parts and% are based on weight unless otherwise specified.

Example 1 Exemplified Dye (4) 0.4 part CI Acid Red 131 1.6 parts Diethylene glycol 13 parts Ethylene glycol 5 parts Ion-exchanged water 80 parts The above components are thoroughly mixed and dissolved in a container, and pressure filtration is carried out with a Teflon filter having a pore size of 1 μm. After that, the ink of the present invention was degassed using a vacuum pump.

Examples 2 to 4 Inks of the present invention were obtained in the same manner as in Example 1 except that the following dyes were used as the dyes in Example 1.

Example 2 Exemplified Dye (6) 0.8 part CI Acid Red 274 1.2 parts Example 3 Exemplified Dye (9) 0.8 part CI Direct Red 227 1.2 parts Example 4 Exemplified Dye (10) 1.1 parts CI Direct Red 9 0.9 parts Comparative Example 1 to 8 An ink of Comparative Example was obtained in the same manner as in Example 1 except that the following dye was used as the dye in Example 1.

Comparative Example 1 Exemplified Dye (4) 2 parts Comparative Example 2 Exemplified Dye (6) 2 parts Comparative Example 3 Exemplified Dye (9) 2 parts Comparative Example 4 Exemplified Dye (10) 2 parts Comparative Example 5 CI Acid Red 131 2 parts Comparative Example 6 CI Acid Red 274 2 parts Comparative Example 7 CI Direct Red 227 2 parts Comparative Example 8 CI Direct Red 9 2 parts Use Example 1 Using the inks of the examples and comparative examples obtained above, an ink was applied using a piezo oscillator. Xerox 4024 paper recording was performed with a recording apparatus having an on-demand type recording head (discharge orifice diameter 50 μm, piezo vibrator driving voltage 80 V, frequency 3 KHz) for discharging the above, and the results shown in Table 1 below were obtained. Table 1 Ink Lightfastness Water resistance Example 1 ○ ○ Example 2 ○ ○ Example 3 ○ ○ Example 4 ○ ○ Comparative example 1 × ○ Comparative example 2 × ○ Comparative example 3 × ○ Comparative example 4 × ○ Comparative example 5 ○ × Comparative Example 6 ○ × Comparative Example 7 ○ × Comparative Example 8 ○ × In addition, the light resistance is 20 with an Atlas Kisenon fade meter.
Evaluated by ΔE (CIEL ^* a ^* b ^* ) after irradiation for a period of time, 0 to
10 was marked as O, 20 to 11 was marked as Δ, and 20 or more was marked as x.

Water resistance was evaluated by OD residual rate (%) after immersion in still water for 5 minutes, and 80 to 100% was ○, 65 to 79% was △, and 65
Less than% was defined as x.

All of the colors were vivid magenta.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Tochihara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-59-78273 (JP, A) JP-A-58 -222165 (JP, A)

Claims (1)

[Claims] 1. A recording liquid comprising a recording agent which is a component for forming a recorded image and a liquid medium for dissolving or dispersing the recording agent, and a dye represented by the following general formula (A) as a recording agent: , CI Acid Red 131, CI Acid Red 27
4. A recording liquid containing at least one dye selected from the group consisting of 4, CI Direct Red 227 and CI Direct Red 9. (However, R ₁ and R ₂ in the above formula represent any substituents, and X
Is a residue of an organic acid, and M represents one kind of base selected from alkali metals, ammonium and organic amines. )