JPH02233782A - Ink and recording method using same - Google Patents

Abstract

PURPOSE:To provide black ink capable giving printed images of little browning or greening, comprising each specific two kinds of water-soluble dye, water-soluble organic solvent and water. CONSTITUTION:The objective ink comprising (A) two kinds of water-soluble dye, i.e. a dye of formula I (e.g. a compound of formula II) and a second dye having structure of a formula III [X1 to X5 are each Li, Na, K or quaternary ammonium group; Q1 and Q2 are each (substituted) phenyl or naphthalene ring] (e.g. a compound of formula IV), (B) a water-soluble organic solvent (pref. glycerin) and (C) water.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an ink and a recording method using the ink, and more particularly to an aqueous ink that provides a black image with improved indoor discoloration properties and outdoor discoloration properties. This invention relates to inks and recording methods using the inks, particularly to inkjet recording methods. (Prior Art) Conventionally, water-based inks in which a water-soluble dye is dissolved in an aqueous medium have been used as inks for fountain pens, felt pens, etc., and inks for inkjet recording. A water-soluble organic solvent is generally added to prevent ink from clogging in ink discharge nozzles.

These conventional inks must provide an image with sufficient density, do not clog the pen tip or nozzle, dry well on the recording material, have little bleeding, and have storage stability. In particular, inkjet systems that utilize thermal energy are required to have excellent heat resistance, and images formed are also required to have sufficient light resistance, water resistance, etc. Also, inks of various hues are prepared from dyes of various hues, of which black ink is the most commonly used for both monochrome and full-color images! This is a necessary ink. Conventionally, dyes for these black inks have mainly been C.I. I. Food Black 2 has been used (Japanese Patent Application Laid-open Nos. 69-93766 and 59-
(See Publication No. 93768).

(Problems to be Solved by the Invention) Among the various required performances mentioned above, the light resistance of the formed image is particularly important.

Conventionally, the problem with the light resistance of images has been mainly fading due to direct sunlight and various types of illumination light, and these problems with fading have been solved by selecting dyes with excellent light resistance. 1. Food Black 2 is known as a dye with excellent light resistance, and as a further improvement on this, JP-A-6
No. 3-22874, No. 62-39676, No. 62-2
50063, No. 62-199667, and Japanese Patent Application No. 63-184743 (dyes represented by general formula (A)) have been proposed. However, recently these dyes have been proposed. In addition to fading, the problem of image discoloration has been brought into close focus.In other words, images made with conventional inks not only suffer from fading, but also discoloration, and this discoloration refers to a change in hue, although the density does not change much. Particularly in the case of black ink, which is used in the largest quantity, the problem of brown discoloration, in which the black color turns brown, is particularly important.Especially in the case of full-color images, this brown discoloration rapidly deteriorates the image quality. This problem of brown discoloration progresses even indoors where there is no direct sunlight, and discoloration is also accelerated depending on the type of recording material used to form the image. This brown problem was unavoidable.

In particular, in the case of so-called coated paper, in which an ink-receiving layer containing a pigment and a binder is formed on a base layer of paper, etc., in order to improve image quality such as color development, clarity, and resolution of the ink,
In the case of plain paper, even ink with little problem of discoloration causes significant brown discoloration, and this problem cannot be solved simply by selecting a dye with good light fastness.

For this reason, the method shown in the specification of Japanese Patent Application No. 184743/1983 has attempted to improve the brown discoloration, and it has become possible to improve the brown discoloration, but the printed matter obtained by the method according to the above specification However, when printed materials are posted outside where there is no direct sunlight, a phenomenon in which the black color fades to a dark edge color to pale green (green discoloration) may be observed. This was something that could not be resolved. Therefore, an object of the present invention is to provide an ink and a recording method that can satisfy the general performance requirements as described above, and can also provide images on coated paper that do not cause problems of brown discoloration or green discoloration. be.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides an ink containing a water-soluble dye, a water-soluble organic solvent, and water, in which the dye has at least a dye represented by the following general formula (A) and a structure represented by the following general formula (B). The present invention relates to an ink containing a dye and a recording method using the ink.

(In the above general formulas A and B, X1 to X5 represent one type or a mixture of lithium, sodium, potassium, and quaternary ammonium compounds, and Q or Q2 represents a phenyl ring or a naphthalene ring which may have a substituent. ) (Function) By selecting and using a dye with a specific molecular structure as the ink dye, there is little indoor discoloration, that is, brown discoloration, even on coated paper, and there is no exposure to direct sunlight. A black ink is provided that provides images with less outdoor discoloration, ie, greening.

Further, in the second aspect of the present invention, it is possible to provide a black image with less brown discoloration and edge discoloration on coated paper using the above-mentioned ink.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The dye used in the ink of the present invention has the general formula (A)
Dye represented by (hereinafter referred to as A dye) and general formula (B)
It is a mixture of dyes shown in (hereinafter referred to as B dye).

In dye A, the cations of x1 to x,, are lithium (Li)
It is a dye that is one or a mixture of two or more of sodium (Na), potassium (κ), or quaternary ammonium compounds, and exhibits a brownish black color tone.

On the other hand, in dye B, the cation is one or a mixture of two or more of lithium, sodium, potassium, or quaternary ammonium compounds, and dye B does not necessarily have to be a single compound, but one that satisfies general formula (B). If so, there is no problem even if it is a mixture of two or more types.

Dye A is a dye that has good water resistance and light resistance against direct sunlight. However, if recorded images printed on coated paper are left indoors, the prints will change from brownish black to bright red in about 4 to 90 days. It has the disadvantage that it turns brown.

In addition, if recorded images printed on coated paper or plain paper are not exposed to direct sunlight but are left outdoors with heavy traffic (presumably high in nitrogen oxides, sulfur oxides, etc.),
The disadvantage is that the printed characters fade to pale green in about 90 days.

On the other hand, B dye is a boriazo dye that is higher than disazo and contains a salt of 8-amino-1-naphthol disulfonic acid such as H acid or K acid in its molecular structure, and uB dye has a dark green to dark purple color depending on its structure. It is a dye, and generally its water resistance and light resistance to direct sunlight are at the same level or lower than A dye, but it is good enough that greening and browning are virtually no problems. It is.

The present invention is characterized by using A dye and B dye together, but if a desired color tone cannot be obtained by the combination of A dye and B dye, other toning dyes may be used in combination. However, there is no problem at all.

Specific examples of the dyes of general formulas (A) and (B) include the following dyes, but are not limited to these dyes.

[Specific examples of dyes of general formula (A)] (X-NH.) A-4 In A-3, X is a mixture of Na:Li=I:2 [Specific examples of dyes of general formula (B) (Specific examples of dyes of general formula (B)) (described in Kaisho 63-105079) (C.I.
Direct Black 19) (C.I. Direct Black 154) B-6 C.
I. Direct Black 166B-7 C. I. Acid Black IB-8 C. I. acid blue-29
B-9 C. I. Acid green 19B-IO
C. ! ．． Acid Green 20B-11 (:.I.
Mordant Green 15 The amounts of the above A dye and B dye used may be any amount as long as the purpose of the present invention is achieved, and are not particularly limited, but the preferable mixing ratio of A dye and B dye is 5: by weight. The ratio ranges from 1 to 1:5.

The total amount of dyes A and B used in the ink of the present invention is not particularly limited, but is generally 0.1 to 15% by weight, preferably 0.3% by weight of the total weight of the ink.
The aqueous medium which accounts for 10% to 10% by weight, more preferably 1.5% to 6% by weight, and is suitable for use in the ink of the present invention is water or a mixed solvent of water and a water-soluble organic solvent. A particularly preferred solvent is a mixed solvent of water and a water-soluble organic solvent, which contains a polyhydric alcohol having an effect of preventing ink from drying as the water-soluble organic solvent. Further, as water, it is preferable to use deionized water rather than ordinary water containing various ions.

Examples of the water-soluble organic solvent used in combination with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isobrobyl alcohol, n-butyl alcohol, see-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, Alkyl alcohols having 1 to 5 carbon atoms such as n-pentanol; Amides such as formamide, dimethylformamide, and dimethylacetamide; Ketones or keto alcohols such as acetone, 2-butanone, and diacetone alcohol; Tetrahydrofuran, dioxane Ethers such as polyethylene glycol, polypropylene glycol, etc.; Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms such as xylene glycol and diethylene glycol; glycerin; ethylene glycol monomethyl (or ethyl) ether;
Diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl)
Lower alkyl ethers of polyhydric alcohols such as ethers: Lower dialkyl ethers of polyhydric alcohols such as triethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether; sulfolane, N-methyl-2- Viloridone, 1.
Examples include 3-dimethyl-2-imidazolidinone.

An appropriate organic solvent is selected from the above organic solvents, but glycerin or polyethylene oxide with a degree of polymerization of 3 to 6 is particularly suitable for preventing ink clogging, and nitrogen-containing cyclic solvents are preferred from the viewpoint of image density and ejection stability. A compound or an ether compound of polyalkylene oxide may be used, and lower alcohols or surfactants are preferably used for frequency response. Therefore, a preferable solvent composition in the present invention is a composition containing the various components described above in addition to water.

The content of the water-soluble organic solvent in the ink generally ranges from 2 to 80% by weight, preferably from 3 to 50% by weight, more preferably from 4 to 40% by weight of the total weight of the ink.

In addition, the water used should account for 45% or more, preferably 60% or more by weight of the entire ink. If the amount of water is small, a large amount of low-volatile organic solvent will remain in the formed image, and the dye will This is not preferable because it causes problems such as migration of images and blurring of images.

In addition to the above-mentioned components, the ink of the present invention may optionally contain a pH adjuster, a viscosity adjuster, a surface tension adjuster, and the like. Examples of the pH adjuster used in the above ink include various organic amines such as diethanolamine and triethanolamine, alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide;
Examples include inorganic alkaline agents such as sodium borate, organic acid salts such as lithium acetate, organic acids, and mineral acids.

The ink of the present invention as described above has a viscosity of 1 at 25°C.
20 cP to 20 cP, preferably 1 to 10 cP, and a surface tension of 40 dyne/cm or more, preferably 50 dyne/cm.
It is preferable to have physical properties of ne/cm or more and a pH of about 4 to 10.

The recording method of the present invention is a recording method characterized by using the above-mentioned ink, and the recording method and recording material are not particularly limited, but in particular, the recording method is an inkjet method, and the recording material is coated paper. A method using the following is particularly effective.

The inkjet method may be any conventionally known method and is not particularly limited, but in the present invention, for example, the method described in Japanese Patent Application Laid-Open No. 54-59936 is used, in which the ink is rapidly heated by the action of thermal energy. Particularly useful is a method in which a volume change is caused, and ink is ejected from a nozzle by the force generated by this state change.

In other words, with this method, when using conventional ink, there was a risk that foreign matter would settle on the heat generating head inside the device, causing problems such as ink failure to eject, but the ink of the present invention is free from such foreign matter. Stable recording is possible because no deposits occur.

The recording material used in the present invention is general plain paper, -
Although any recording material such as F-quality paper, coated paper, and plastic film for OHP etc. can be used, remarkable effects are particularly achieved when coated paper is used.

These coated papers are made of paper such as plain paper or high-quality paper, and have an ink-receiving layer that serves as a pigment and binder on the surface to improve color development, clarity, dot shape, etc. with ink. That is.

In the case of these coated papers, those using fine pigments such as synthetic silica with a BET specific surface area of 35 to 650 rn'/g produce images with excellent color development and clarity, but conventional When ink is used, although the theoretical reason for this problem is unknown, the problem of discoloration over time is particularly noticeable with images made with black ink, and this is a major problem not only with black monochrome images but also with full color images. There is.

In addition, similar to these coated papers, recording materials in which a thin layer of pigment and binder is provided on the paper base, and the fibers of the base paper are mixed in this layer also cause similar problems. There is.

It has been found that even if a black monochrome image or a full color image is formed using the ink of the present invention on the coated paper as described above, the problem of brown discoloration as described above does not occur. Therefore, according to the method of the present invention, the BET specific surface area is 35 to 6.
Recorded images that do not cause discoloration indoors for a long period of time using not only coated paper using a pigment of 50 rn'/g, but also coated paper using a pigment with a BET specific surface area of less than that, plain paper, and any other recording material. can be provided.

Furthermore, C.I., which is conventionally known for coated paper and plain paper. I
．． After recording an image with Food Black 2 or an ink using only the dye represented by the general formula (A) of the present invention, the recorded image is not exposed to direct sunlight (therefore, conventional lightfastness evaluation cannot be performed). If posted outdoors with heavy traffic,
A phenomenon in which a black recorded image fades to dark green to light green after about 10 to 90 days (marginal discoloration) was observed, and this often became a problem especially in the case of full-color recorded images.

However, it has been found that when monochrome recording or full color recording is performed using the ink of the present invention, the green discoloration described above does not occur even if the poster is displayed outdoors for about 90 days.

As is clear from the above, by using the ink and recording method of the present invention, brown discoloration and green discoloration of black images, which have been problems in the past, can be significantly improved.

Incidentally, the recording method using the inkjet method and the various recording materials described above are well known and have been proposed by the applicant, but these recording methods and recording materials may be used as they are in the present invention. I can do it.

(Examples) Next, the present invention will be explained in more detail by giving Examples, Comparative Examples, and Usage Examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

Example 1 (Ink-1) 2.0 parts of the dye of Specific Example A-3 0.5 parts of the dye of Specific Example B-1
Dye 0.5 part diethylene glycol
30.0 parts polyethylene glycol 400
5.0 parts N-methyl-2-pyrrolidone 5.
0 parts sodium hydroxide 0.1 parts water
57.0 parts The above ingredients were mixed and stirred while keeping the temperature at 30 to 35°C to sufficiently dissolve them, and then filtered under pressure using a fluororesin membrane filter with a pore size of 0.22 μm to obtain the present invention. Ink 1 was obtained.

Examples 2 to 5 Inks 2 to 5 comprising the following components were obtained in the same manner as in Example 1 above.

Ink-2 Dye of Specific Example A-2 O. S part Dye of the above specific example B-7 2.0 parts tetraethylene glycol 10, O part diethylene glycol
10.0 parts Tetra Grime
10.0 parts Urea 1.0
1! IIs1.2-penzisothiazolin-3-one (
Preservative) 0.01 part water
66, 5 parts A
Example 1 (Ink 3) 2.0 parts of the dye of Example A-1 0.4 parts of the dye of Example B-4 Ethanol
3.5 parts glycenol
5.0 parts diethylene glycol 1
0.0 part lithium carbonate 0.1 part permanent 79, O part Bunka Example A (Ink 4) Dye of the above specific example A-1 1.0 parts Dye of the above specific example A-2 1.0 parts above specific example B-9
Dye 0.5 part diethylene glycol
25.0 parts ethyl alcohol
2.5 parts lithium hydroxide (]Ot aqueous solution)
0.5 parts water 7
0.0 Part Length ▲ 1 (Ink 5) 1.5 parts of the dye of Specific Example A-4 1.5 parts of the dye of Specific Example B-5 1.5 parts Diethylene glycol 40.0 parts Glycerin
5.0 parts triethanolamine
2.0 parts water
50.0 parts of inks 6 to 1 O of comparative examples were obtained in the same manner as in Example 1.

1 (Ink-6) All the dyes in the ink of Example 1 were replaced with the dyes of Example A-3 and 3.
Exactly the same composition except that 0 part was substituted.

Lematsu Bessatsu (Ink 7) All the dyes in the ink of Example 2 were replaced with the dyes of Example B-7 2.
Exactly the same composition except that 5 parts were substituted.

Akira Agematsu (Ink 8) Exactly the same composition except that all the dyes in A-1 of the ink of Example 3 were replaced with 2.0 parts of I. Food Black 2.

Example A (Ink-9) 0.5 part of B-9 dye of the ink of Example 4 was added to Example A-4.
Exactly the same composition except that 0.5 part of the dye was substituted.

Example 1 (Ink 10) All the dyes in the ink of Example 5 were replaced with the dyes of Example A-4 and 3.
Exactly the same composition except that 0 part was substituted.

Usage Examples The inks of Examples 1 to 5 and Comparative Examples 1 to 5 were loaded into an inkjet printer and printed, and the resulting recorded images were evaluated. Printing conditions are shown in Usage Examples 1 to 5.

Also, the evaluation results are shown in Table 1.

Usage Example 1 A partially modified inkjet printer BJ-80A manufactured by Canon ■ is equipped with the inks (Ink-1 and Ink-6) shown in Example 1 and Comparative Example 1, and used as a recording material for BJ-80A. A test pattern was printed using inkjet printer paper (coated paper, manufactured by Canon ■), and evaluation was performed using the evaluation methods and evaluation criteria T to T4 described below.

Usage Example 2 A partially modified inkjet printer BJ80A manufactured by Canon ■ was equipped with the inks (Ink-2 and Ink-7) shown in Example 2 and Comparative Example 2, and inkjet coated paper NM was used as the recording material. (Product name: Made by Mitsubishi Paper Mills)
A test pattern was printed using the following, and evaluation was performed in the same manner as in Use Example 1.

Usage Example 3 A partially modified inkjet printer BJ-130 manufactured by Canon ■ is equipped with the inks (Ink 3 and Ink 8) shown in Example 3 and Comparative Example 3, and copy paper Xerox 40240P ( Trademark: US Xe
A test pattern was printed using non-coated paper (manufactured by Rox Corp.), and evaluation was performed in the same manner as in Use Example 1.

Usage Example 4 A Canon Color Bubble Jet Covia 1 (trade name), an inkjet copying machine manufactured by Canon ■, was partially modified, and the inks shown in Example 4 and Comparative Example 4 (Ink-4 and Ink-4) were used as black ink. 9), a test pattern was printed using special paper (coated paper) of Color Bubble Jet Cobia 1 as a recording material, and evaluation was performed in the same manner as in Use Example 1.

Usage Example 5 The black ink print cartridge of an inkjet printer Paintjet (trade name) manufactured by Hewlett-Buckard Company in the United States was partially modified, and the inks shown in Example 5 and Comparative Example 5 (Ink 5 and Ink 10) were used. A test pattern was printed using paper (coated paper) included in the paint jet as a recording material, and evaluation was performed in the same manner as in Use Example 1.

Evaluation method and evaluation criteria TI = Water resistance of printed matter A test piece with a 10 mm x 30 m long solid print is left indoors for about 12 hours, and the optical density (001) is measured. The test piece was immersed in still water (ion-exchanged water) for 5 minutes, then air-dried, and the optical density (002) of the test piece after immersion was measured, and the OD residual rate (=(002/
00 + ) x 1 00 (9&) ) was calculated and evaluated.

a: OD residual rate ≧90 (%) b: 70≦OD residual rate <90 (J;) c: 5
0≦OD residual rate<7 0 (*)d: OD residual rate<
5 0 (*) T2: Light resistance of printed matter to direct light A test piece with a solid print of about 10 ma +
01) is measured. The test piece is irradiated with Canon light for 50±3 hours using an Atlas Canon Fade Tester (Ci35: trade name), and the optical density (002) of the test piece after irradiation with Canon light is measured. OD residual rate (
= (002/00,) x 100 (t) ') and evaluated based on the following criteria.

a: OD residual rate ≧ 9 0 (*) b: 70 ≦ OD residual rate < 9 0 (!k) c: 50 ≦
OD residual rate < 7 0 ('!) d: OD residual rate < 5
0 (!k) T3: Discoloration (brown discoloration) of printed matter due to being left indoors TI. T
To accelerate brown discoloration, a test piece similar to 2 was left in a light-shielded tank where the ozone concentration was always maintained within the range of 0.1±0.05% by volume for 30 minutes before and after the test. The color difference ΔECIE (L〒b'') of the printed matter was measured.

a: ΔECIE (L”a”b”) <5b=5≦ΔEc
+E(L″a*1,*)≦10C:ΔE(,,(L″a
``b'') > I OT4 2 Discoloration (green discoloration) of printed material due to being left outside T, , A test piece similar to T2 was left outside facing a busy road out of direct sunlight and rain for 90 days. , color difference ΔEc+ of printed matter before and after the test
F. (L'a″b″) was measured.

a: ΔEc+g(L”a”b”) < 5b: 5≦ΔE
c+. :(L”a”b”)≦10c 2 ΔEc+E
(L'a"b") > 1 0 (hereinafter margin) is now possible.

Monitoring T,: Water resistance of printed matter T2: Light resistance of printed matter T: Discoloration due to being left indoors T4: Discoloration due to being left outdoors One disaster, one action, one action abaaa aaaaa aaaaa aaaaa

Claims (4)

[Claims] (1) In an ink containing a water-soluble dye, a water-soluble organic solvent, and water, the dye contains at least a dye represented by the following general formula (A) and a dye having a structure represented by the following general formula (B). An ink characterized by containing: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(B) (In the above general formulas A and B, X_1 to X_5 are lithium, sodium, potassium, and quaternary ammonium compounds. One type or a mixture is shown, and Q_1 or Q_2 represents a phenyl ring or a naphthalene ring that may have a substituent.) (2) In a recording method performed by applying ink to a recording material, the ink contains a water-soluble dye, a water-soluble organic solvent, and water, and the dye is at least a dye represented by the following general formula (A). A recording method characterized by using an ink containing a dye having a structure represented by the following general formula (B). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(B) (In the above general formulas A and B, X_1 to X_5 are lithium, sodium, potassium, and quaternary ammonium compounds. One type or a mixture is shown, and Q_1 or Q_2 represents a phenyl ring or a naphthalene ring that may have a substituent.) (3) The recording method according to claim 2, wherein recording is performed using an inkjet method. (4) The recording method according to claim 2, wherein the recording material has an ink-receiving layer made of a pigment and a binder on its surface.