JPH03122171A - Formation of color image - Google Patents

Abstract

PURPOSE:To obtain a color image excellent in quality by recording with specific yellow, magenta, cyan and black aqueous inks by ink jet printing. CONSTITUTION:An image is recorded by ink jet printing with an aqueous ink prepared by adjusting (A) a yellow ink containing one kind or more of dyes of formula I, (B) a magenta ink containing one kind or more of dyes of formulas II and III, (C) a cyan ink containing one kind or more of dyes of formula IV and (D) a black ink of dyes of formulas V, VI and VII to provide a color image excellent in water resistance and light resistance, high in optical concentration and bright in color tone, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method of forming a color image by an inkjet method using a combination of yellow, magenta, cyan, and black aqueous inks.

(b) Conventional technology The inkjet method uses various ink ejection methods (for example, an electrostatic suction method, a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, a method that heats the ink to foam it, and applies pressure at that time). Ink droplets (d
roplCt), and a part or all of it is attached to a recording material such as paper to perform recording.

It is known that in this method, a color image is formed by using a plurality of nozzles and using ink of a plurality of different hues in which various dyes are dissolved in water or an organic solvent. (JP-A-57-5771, JP-A-59
-96967, JP-A-62-1.92475. Tokukai Showa 6
2-199666) (c) Problems to be Solved by the Invention The ink used in such an inkjet system is required to have the following performance.

(I) It is possible to perform good recording on recording paper with high versatility and high size as a recording material.

(2) To provide images with excellent water resistance, light resistance, etc.

(3) Excellent resolution or color tone reproducibility in color 1iIiii imaging.

(4) High dissolution stability or storage stability with respect to liquid medium components, and less clogging of the discharge orifice! 1(
.

(5) Providing an image with high optical density and clear color tone.

(6) Good hue, water resistance, and light resistance when mixing colors (7)
The ink must have a negative Ames test result.

However, there has been no known method for forming a color image using an ink that satisfies all of the properties (I) to (7).

(d) Means for Solving the Problems The present inventors have discovered that the properties (I) to (7) required of the ink are largely influenced by the properties of the water-soluble dye contained in the ink. As a result of continuing research on dyes, a specific group of dye combinations were found to
) The inventors have discovered that this is a dye suitable for color image forming methods that satisfies all the characteristics, leading to the present invention.

That is, the present invention provides a method for forming a color image by an inkjet method using yellow, magenta, cyan, and black water-based inks, which includes one or more dyes represented by the following general formula (I) as the yellow ink dye. The magenta ink contains one or more dyes represented by the following general formula (II) or (II+), and the cyan ink contains one or more dyes represented by the following general formula (IV).
Contains one or more types of dyes represented by the following general formula (V) or (VI) or (VU
) A method for forming a color image, characterized by containing one or more types of dyes represented by:

(However, in the formula, the former represents a hydrogen atom, an alkali metal, ammonia 11, or an organic amine salt.) However, R3, 1 and 2 are never hydrogen atoms at the same time. N is the same as above. ) (However, the formula middle person is C11, -CH, -0-3O, M or Bankado C1 (= CI + 2. A is the same as above.) (Ill) (However, X in the formula is C1, NIICH ,CH,OH or N
(CH, CIl, oH) represents z, - is the same as above. ) (However, in the formula, CuPc represents a copper phthalocyanine skeleton, A is the same as above, ■ represents 0.1 to 0.95, m
represents 1 to 3. ) (However, in formula 1, R1 and R2 are hydrogen atoms, hydroxyl groups, amino (
However, in the formula, R1 and R4 represent a hydrogen atom, So, or M, and R1 and R1 are not the same. R6 and R5 represent a hydroxyl group or an amino group, and R5 and R6 are not the same. Old±same as above. ) (However, in the formula, R7,1 represents a hydrogen atom or 503M, and R9, R represents a hydroxyl group or an amino group. Same as above.) Next, the present invention will be explained in more detail. As a dye for water-based ink in the inkjet method.

The characteristics of water-based ink required in general inkjet systems, that is, the characteristics (I) to (7) above, are required, but all four colors (i.e., yellow, magenta, cyan, and black) are required. It was extremely difficult for all dyes to have the same level of properties (I) to (7), but through detailed research by the present inventors, it was possible to achieve this by combining a group of specific dyes as described below. Formation of color images using the most excellent inkjet method has been realized.

The dyes represented by the above general formulas (I) to (■) used in the present invention and which mainly characterize the present invention may be any dye as long as it is contained in the above general formulas (I) to (■). However, particularly preferred specific examples include the following. Further, although the sulfonic acid group and the carboxyl group are shown as alkali metal salts or free acids, they may also be other ammonium salts, amine salts, etc.

Yellow 廿-1 SO, Na 5o, Na -2 So, Li o31j -3 -1 CH,,=C11-O□S o3Na So, Na -2 M-3 -4 CH2Cl, 011 -5 K-3 B K -4 o3Na So, Na K-5 SO, Na 0JNa K-6 K-7 03Na So, Na Cyan dye y-1 y-2 K-1 K-2 K-8 K-9 K-10 Used in the present invention The water-based ink has the general formula (I
) to (■) are used to prepare water-based inks of four colors, yellow, magenta, cyan, and black, respectively, but the methods for preparing water-based inks of these colors are all based on conventional technology. It is good to follow. Furthermore, the water-based ink of each color used in the present invention needs to contain one of the dyes (I) to (VII) above or a plurality of dyes of the same color. Other dyes not included in formulas (I) to (■) are not included.2 The content of each of the above-mentioned specific dyes in the ink depends on the type of liquid medium component, the properties required of the ink, etc. However, it is generally 0.1 to 20% by weight, preferably 0.5% by weight, based on the total weight of the ink.
The content ranges from 1 to 15%, more preferably from 1 to 10%.

Of course, these dyes can be used alone or in combination of two or more. If other direct dyes or acid dyes are used in combination, the balance of properties (I) to (■) will be disrupted, so they should not be used.

A suitable solvent for use in the ink of the present invention is a mixed solvent of water and an organic solvent, preferably one containing a polyhydric alcohol having an effect of preventing drying of the ink as the organic solvent. Also, the water is not ordinary water that contains various ions.

Preferably, deionized water is used. Examples of organic solvents used in combination with water include 1, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,4 butylene gelicol, 2,
3-butylene gelicol, glycerin, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol isopropyl ether, propylene glycol-n-butyl ether , dipropylene glycol monoethyl ether, dipropylene glycol-〇-butyl ether, dipropylene glycol isopropyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol-n-butyl ether, glycerin-α, γ- Examples include dimethyl ether and glycerin α-mono-butyl ether, and one or more of these may be appropriately selected and used.

The amount added is generally 4 to 50%. Further, the viscosity of the ink is generally 1.2 to 7. Ocps, surface tension is adjusted to 30-60 dyne/cm, and ptl is adjusted to 4-11. Furthermore, the ink according to the present invention contains monoethanolamine and jetanolamine to an extent that does not impair its properties.

Alkanolamines such as triethanolamine and di-1so-propaturamine; methanol.

Ethanol, n-propertool, 1so-propertool, n-butanol, 1so-butanol.

5ee-butanol, tert-butanol, n-amyl alcohol, 1so-amyl alcohol.

2-methyl-1-butanol, 2-pentanol.

3-pentanol, 2-methyl-2-butanol.

Alcohols such as amyl carbinol, methyl isobutyl carbinol, amyl carbinol, and ethyl butyl alcohol; sodium dehydroacetate, 4-chloro-3-
Antifungal agents such as ethylphenol and hexahydro-1,3.5-)-lis(2-hydroxyethyl)-1,3.5-)-riazine can be used.

The ink of the present invention prepared from such components has recording characteristics (signal response, stability of droplet formation, ejection stability, long-term continuous recording, long-term recording pause of 1?tl) by itself. Post-discharge stability) The storage stability, fixing property to the recording medium, and the light resistance, weather resistance, and water resistance of the recorded image are all well-balanced and excellent.

Further, in order to prepare ink used in an inkjet system that charges the ink, 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 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 present invention uses four colors of ink as described above.

A color image is formed by an inkjet method, and any conventionally known method can be used as the inkjet method.

Recording materials that can be used in the method of the present invention include various inkjet recording papers and O
Even if you use a plastic sheet for HP, it is possible to record valuable records, and other paper that is widely used for office purposes such as copy paper, report paper, bond paper, slip paper, continuous slip paper, and computer paper. Any embossing paper or the like can be used, and these papers can be either low-size paper or high-size paper.

According to the present invention as described below, the dyes used in the four color aqueous inks used in the present invention are as follows.

All of them have the same level of dissolution stability and storage stability in liquid media, so they are suitable as water-based inks for general inkjet methods, and they do not cause precipitates or changes in the color tone of the dye. Excellent discharge stability,
It is possible to maintain ejection responsiveness and the like. Since the dyes of the aqueous ink of any color have excellent light fastness, water resistance, sharpness, etc., it is possible to provide color images of excellent quality.

Some water-based inks used in conventional inkjet systems are known to have excellent inkjet suitability for any color, but they are not suitable for all four colors (yellow, magenta, cyan, and black) and mixed colors. Since no water-based ink was known that had the same level of suitability for various types of ink, it was not possible to provide a color image that was balanced in all respects. However, in the present invention, a specific group of dyes is used By using four color aqueous inks in selection and combination, it has been achieved to provide color images of superior quality to a degree not possible with the prior art.

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

Reference Example 1 Yellow, magenta, cyan, and black aqueous inks used in Example 1 were prepared by mixing the following components and then filtering under pressure using a Teflon filter with an average pore size of 0.45 μI.

Yellow ink (I) Exemplary dye Y-13 parts water
86 parts polyethylene glycol Zoo L
1 part Magenta ink (I) Exemplary dye M-1 Water diethylene glycol glycerin Cyan ink (I) Exemplary dye cy-1 Water ethylene glycol Polyethylene glycol 300 3 parts 85 parts 10 parts 2 parts 4 parts 81 parts 5 parts 10 parts Black ink 1 Exemplary dye Bk-1 Exemplary dye Bk-2 Water triethylene glycol yellow ink (2) Exemplary dye Y-2 Water tetraethylene glycol magenta ink (2) Exemplary dye M-2 Water diethylene glycol glycerin cyan ink 2) Exemplary dye cy-2 Water Ethylene Glycol Polyethylene Glycol 200 3 parts 2 parts 80 parts 15 parts 4 parts 86 parts 10 parts 3 parts 77 parts 13 parts 7 parts 4 parts 81 parts 10 parts 5 parts Black ink 2L Exemplary dye nk-6 3 parts Exemplary dye Bk-72 Department water
85 parts triethylene glycol 10 parts Reference Example 2 In the same manner as in Reference Example 1, four color aqueous inks of yellow, magenta, cyan and black used in a comparative example having the following composition were prepared.

Yellow Ink Acid Yellow 23 3 parts water
82 parts Tetraethylene glycol 15 parts Magenta Ink Acid Red 92 3 parts Water
83 parts diethylene glycol 7 parts glycerin
7 parts Cyan Ink Acid Blue 9 Water Polyethylene Glycol 200 Black Ink Direct Black 19 Water Triethylene Glycol 3 parts 87 parts 10 parts 5 parts 80 parts 15 parts Example I Using each ink obtained in Reference Example 1 in L. By Sharp inkjet ■0720.

When images of each color were formed and the following studies (T1) to (T6) were conducted, good results were obtained in all cases as shown in Table 1 below.

(T1) Long-term storage stability of ink: After sealing the ink in a glass container and storing it at -20℃ and 60℃ for 6 months, the precipitation of insoluble matter, changes in liquid physical properties, and changes in color tone are evaluated.
:11? ;Evaluated by SL.

(T2) Ejection stability: Continuous ejection was performed for 24 hours in 'R atmosphere at room temperature, 5° C., and 40° C., and the quality of the formed image was evaluated.

('r'3) Ejection responsiveness: Intermittent ejection every 2 seconds and ejection after being left for 2 months were evaluated based on the presence or absence of clogging at the tip of the control orifice.

(T4) Light resistance of recorded images 41 of images recorded on two papers
The concentration was set at 41, and the concentration was evaluated based on the rate of decrease in concentration (%) after being exposed to indoor light for one month.

(T5) Hue of W color: The hue of Y+M, M+C, and C+Y was evaluated.

(T6) Ames test: TA98°TAL by the method of “Environmental Mutagen Experimental Methods” edited by Yatabe Tajima et al. (FJ Dansha)
An Ames test of the ink was carried out using two strains of A. oo. If the number of revertant colonies was twice or more the number of colonies in the target test, it was determined to be positive, and if it was less than twice the number of colonies in the target test, it was determined to be negative.

Comparative Example 1 An image was formed using each ink of Reference Example 2 in the same manner as in Example 1, and evaluated in the same manner, and the results are shown in Table 1 below.

Example 2 Yellow ink (I), magenta ink (I) of Reference Example [
), cyan ink (I), and black ink (I), respectively, and a multicolor image was reproduced by the apparatus of Example 1. The resulting image had extremely clear colors and good color reproduction.

Example 3 Yellow ink (2) and magenta ink (2) of Reference Example 1
), cyan ink (2), and black ink (2), respectively, and a multicolor image was reproduced by the apparatus of Example 1. The resulting image had extremely clear colors and good color reproduction.

Example 4 Comparative Example 2 A multicolor image was reproduced in the same manner as in Example 1 using the four color inks of yellow, magenta, cyan, and black from Reference Example 2, respectively. The resulting images had insufficient color reproducibility and were significantly inferior in clarity and light fastness compared to the examples.

Table 1 Example [Fishing□su]αヱ``River - Good Good Good [1 ode] Discharge stability Discharge response Record! The 11th nature of the image 3;, +115(I)41/1- Y(2) Good Good Good 90% Good M(2 Good Good Good 80% Good C(2 Good Good Good 90% Good Rk(2 Good Good Good 80% )’tsH@ ” E HigenjJ1- Discharge response EINIQi15 promotion -- “Retirement” 1 Missing color 1 ames test Good, non-discharge & failure occurrence After 2 months of neglect After 2 months of neglect Non-discharge Non-discharge 50% or less 50% or less inferior inferior Negative Negative Non-discharge & Raw non-discharge failure occurrence After 2 Rikizuki stones are released After 2 Rikizuki is left unattended Non-discharge Non-discharge 50% or less 80% inferior Negative VI)

Claims (1)

[Scope of Claims] A method for forming a color image by an inkjet method using yellow, magenta, cyan, and black water-based inks, containing one or more dyes represented by the following general formula (I) as the yellow ink dyes. The following general formula (II) or (III) is used as a dye for magenta ink.
Contains one or more dyes represented by the following general formula (IV) as a cyan ink dye, and contains one or more dyes represented by the following general formula (IV) as a black ink dye.
A method for forming a color image, comprising one or more dyes represented by V), (VI), or (VII). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (However, M in the formula represents a hydrogen atom, an alkali metal, ammonium, or an organic amine salt.) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (However, , where A is CH_2-CH_2-O-SO_3
M or CH=CH_2. H is the same as above. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (However, in the formula, X represents Cl, NHCH_2CH_2OH or N(CH_2CH_2OH)_2, and M is the same as above.) ▲There are mathematical formulas, chemical formulas, tables, etc. (IV) (However, in the formula, CuPc represents a copper phthalocyanine skeleton, M is the same as above, l represents 0.1 to 0.95, and m
represents 1 to 3. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(V) (However, in the formula, R_1 and R_2 represent a hydrogen atom, a hydroxyl group, and an amino group. However, R_1 and R_2 are never hydrogen atoms at the same time. M is Same as above.) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(VI) (However, in the formula, R_3 and R_4 are hydrogen atoms or SO_3
M, and R_3 and R_4 are not the same. R_5, R
_6 represents a hydroxyl group or an amino group, and R_5 and R_6 are not the same. M is the same as above. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(VII) (However, in the formula, R_7 and R_8 are hydrogen atoms or SO_3
M represents R_9 and R_1_0 represent a hydroxyl group or an amino group. M is the same as above. )