JPH08310116A - Formation of color image - Google Patents

Abstract

PURPOSE: To obtain a color image of excellent quality by using inks containing paints of which the free acid forms are respectively represented by specific formulae as yellow, magenta, cyan and black inks. CONSTITUTION: In a method forming a color image by emitting aq. inks of yellow, magenta, cyan and black, ink containing one or more kind of paint represented by formula I is used as yellow ink and ink containing one or more kind of paint represented by formula II is used as magenta ink. One or more kind of paint represented by formula III is added as cyan ink and ink containing a mixture of paints of which the free acid forms are represented by formula IV is used as black ink. In the formulae I-TV, X, Y, Z and W are a hydrogen atom, a methoxy group or an ethoxy group, R is a -C2 H4 OSO3 H group, a -C2 H4 OH group or a -CH=CH group, Cu-Pc is a copper phthalocyanine residue, l is an integer of 0-3 and m is an integer of 1-4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a color image, and more particularly to a method for forming a full color image using a combination of yellow, magenta, cyan and black aqueous inks by an ink jet system.

[0002]

2. Description of the Related Art The ink jet system is one in which a small amount of ink is ejected from an orifice by various systems and adhered to a recording material to form an image. The ink used in such an ink jet system is as follows. Performance is required. (1) A good image can be obtained on non-coated paper such as electrophotographic paper, fan-hold paper, bond paper, art paper or coated paper that is commonly used in the office as a recording material. (2) To give an image excellent in water resistance and light resistance. (3) The dissolution stability or storage stability with respect to the liquid medium component is high, and the discharge orifice is unlikely to be clogged. (4) To provide an image with high optical density, clear color tone and good reproducibility.

In order to satisfy such strict requirements, for example, JP-A-54-89811 and JP-A-55-5436.
7, JP-A-57-76071, JP-A-57-164
170, JP-A-57-195775, JP-A-57-
197191, JP-A-58-12786, JP-A-5
8-101171, JP-A-59-75964, JP-A-59-106989, JP-A-62-1974466.
JP-A-62-199665, JP-A-62-199.
666, JP-A-62-199667, JP-A-63-
28690, JP-A-2-131983, JP-A-2-
233773, JP-A-3-122171, JP-A-3
-203970, JP-A-4-168166, JP-A-5-155004, JP-A-5-155005, JP-A-5-155006, JP-A-5-1948989, JP-A-5-214259, JP-A-6- 99656, JP-A-6-100811, JP-A-6-106735,
Although many patents have been filed such as JP-A-6-136309, JP-A-6-143794 and JP-A-6-152899, a satisfactory one has not been obtained yet.

[0004]

The present invention is based on the above (1).
It is intended to provide an inkjet recording method which gives an excellent color image by using an ink which satisfies all of the requirements (4) to (4) in good balance.

[0005]

The inventors of the present invention have found that the characteristics (1) to (4) required for ink are greatly influenced by the characteristics of the water-soluble dye contained in the ink, and By combining a specific dye, the above (1)-
The inventors have found that an ink suitable for a color image forming method that satisfies all the characteristics of (4) can be obtained, and completed the present invention.

That is, the present invention is a method for forming a color image by ejecting yellow, magenta, cyan and black aqueous inks by an ink jet system, wherein the yellow ink is represented by the following general formula [I] or general formula [I]. II], and the magenta ink contains one or more dyes represented by the following general formula [III] or [IV], and the cyan ink contains the following general formula [III]: V], and the black ink contains a mixture of the dyes represented by the following general formulas [VI] and [VII]. It is a summary.

[0007]

Embedded image

(In the formula, X, Y, Z and W each independently represent a hydrogen atom, a methyl group, a methoxy group or an ethoxy group, and R is -C ₂ H ₄ OSO ₃ H group, -C ₂ H ₄ OH. Represents a group or a —CH═CH ₂ group.)

[0009]

[Chemical 9]

(In the formula, R has the same meaning as in the above general formula [I].)

[0011]

[Chemical 10]

(In the formula, R has the same meaning as in the above general formula [I].)

[0013]

[Chemical 11]

(In the formula, V represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R represents the same meaning as in the general formula [I].)

[0015]

[Chemical 12]

(Wherein Cu-Pc represents a copper phthalocyanine residue, l represents an integer of 0 to 3, m represents an integer of 1 to 4, and l + m represents an integer of 2 to 4; Represents the same meaning as in the general formula [I].)

[0017]

[Chemical 13]

(In the formula, R has the same meaning as in the above general formula [I].)

[0019]

Embedded image

(In the formula, U represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R represents the same meaning as in the general formula [I].) Next, the present invention will be described in more detail. To do. A variety of performances are required as dyes for water-based inks used in the inkjet method, and especially in the case of forming a color image, in addition to general performances, yellow, magenta, cyan, and black dyes have light resistance. It is important that the properties such as water resistance and water resistance are well balanced, and the color rendering relationship is good, and it is extremely difficult to find a combination of four color dyes having such characteristics. That was,
According to the present invention, it has been possible to successfully form a color image by an excellent inkjet method by combining a group of specific dyes as described below.

The dye used in the present invention may be in the form of the free acid represented by the above general formulas [I] to [VII], or may be in the form of a salt. In addition, some acid groups in one molecule of the dye may be in the form of a salt, and a salt form dye and a free acid form dye may be used in combination. Examples of such salts include salt forms of alkali metals such as sodium, lithium and potassium, ammonium salts which may be substituted with an alkyl group or a hydroxyalkyl group, and salts of organic amines. Examples of this organic amine include a lower alkylamine, a hydroxy-substituted lower alkylamine, a carboxy-substituted lower alkylamine, and an alkyleneimine unit having 2 to 4 carbon atoms.
Examples include polyamines having 10 or the like. In the case of the above salt form, the type of salt is not limited to one type, and a plurality of types may be mixed.

The above-mentioned general formula [I] used in the method of the present invention:
Examples of the dye represented by [VII] include the above general formulas [I] to
The dye is not particularly limited as long as it is included in [VII], and any dye may be used, but preferred examples thereof include the following free acid forms.

[0023]

[Chemical 15]

[0024]

Embedded image

[0025]

[Chemical 17]

[0026]

Embedded image

[0027]

[Chemical 19]

[0028]

Embedded image

[0029]

[Chemical 21]

[0030]

[Chemical formula 22]

The water-based ink used in the present invention comprises four colors of yellow, magenta, cyan and black prepared by using the dyes represented by the above formulas [I] to [VII]. Although the ink is an ink, any method for preparing the water-based ink of each of these colors may follow the conventional technique. The content of the above-mentioned specific dye in each ink is 0.1 to 8% by weight, preferably 0.5 to 5%, in the total weight of the ink. In the black ink, the general formula [V
The mixing ratio of the dyes of I] and [VII] is usually [VI] / [VII] = 5/95 to 40/60, preferably 10/90 to 30/70 by weight. The solvent used in the ink of the present invention is water and a water-soluble organic solvent, and examples thereof include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, 1 to 4 carbon atoms such as isobutyl alcohol
Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and 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 the like, alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms; glycerin; ethylene Glycol methyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (also Lower alkyl ethers of polyhydric alcohols ethyl) ether; N- methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone. 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 5 to 40% by weight based on the total weight of the ink.
It is preferably in the range of 10 to 30% by weight. On the other hand, water is used in the range of 45 to 95% by weight, preferably 65 to 85% by weight, based on the total weight of the ink. 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, light resistance of a recorded image, weather resistance, water resistance, etc. are all well balanced and excellent. And 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 cation, anion or nonionic surface active agents, surface tension adjusting agents such as diethanolamine and triethanolamine, and pH adjusting agents using a buffer solution. , Antifungal agents and the like.
In particular, an alkali metal salt of acetic acid, citric acid or phosphoric acid is contained in an amount of 0.1 to 5% by weight, preferably 0.1% by weight, based on the total weight of the ink.
Addition of 5 to 3% by weight to the ink improves the storage stability of the ink.

[0034]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Examples. In the text, parts and% are based on weight unless otherwise specified. Reference Example 1 (Preparation of Ink) The following components were mixed, and then pressure-filtered with a Teflon filter having an average pore size of 0.45 μm,
After degassing, yellow, magenta, cyan, and black aqueous inks used in Examples 1 and 2, respectively, were prepared. In the following inks, each dye is N
a Used in the form of salt.

Yellow ink (1) Exemplified dye Y-1 2 parts Water 83 parts Diethylene glycol 10 parts Polyethylene glycol # 200 5 parts Magenta ink (1) Exemplified dye M-1 2 parts Water 83 parts Diethylene glycol 7 parts Polyethylene glycol # 200 8 Cyan ink (1) Exemplified dye C-1 2 parts Water 83 parts Diethylene glycol 10 parts Polyethylene glycol # 200 5 parts Black ink (1) Exemplified dye BK-1 3 parts Exemplified dye BK-7 0.6 parts Water 81.4 Part Diethylene glycol 10 parts Polyethylene glycol # 200 5 parts

Yellow ink (2) Exemplified dye Y-5 3 parts Sodium citrate 0.5 part Water 84.5 parts N-methylpyrrolidone 5 parts Glycerin 7 parts Magenta ink (2) Exemplified dye M-4 3 parts Citric acid Soda 0.5 parts Water 84.5 parts N-methylpyrrolidone 5 parts Glycerin 7 parts Cyan ink (2) Exemplified dye C-2 3 parts Sodium acetate 0.5 parts Water 82.5 parts 2-Pyrrolidone 7 parts Glycerin 7 parts Black ink (2) Exemplified dye BK-3 2.5 parts Exemplified dye BK-8 0.5 part Sodium phosphate 0.5 parts Water 84.5 parts N-methylpyrrolidone 5 parts Glycerin 7 parts

Yellow ink (3) Exemplified dye Y-2 2 parts Water 78 parts Diethylene glycol monobutyl ether 3 parts Polyethylene glycol # 300 17 parts Magenta ink (3) Exemplified dye M-5 2 parts Exemplified dye M-2 1 part Water 77 Part Diethylene glycol monobutyl ether 3 parts Polyethylene glycol # 300 17 parts Cyan ink (3) Exemplified dye C-4 3 parts Water 77 parts Diethylene glycol monobutyl ether 3 parts Polyethylene glycol # 300 17 parts Black ink (3) Exemplified dye BK-2 3 parts Exemplified dye BK-7 0.9 part Water 76.1 parts Diethylene glycol monobutyl ether 3 parts Polyethylene glycol # 300 17 parts

Example 1 One set of four colors of yellow ink (1), magenta ink (1), cyan ink (1) and black ink (1) obtained in Reference Example 1 and yellow ink (3) and magenta ink An inkjet printer (manufactured by MJ-700 U-2-C Epson Co., Ltd.) using each set of recording liquids of four colors (3), cyan ink (3) and black ink (3). Recording was performed, and the quick-drying property and the print quality were evaluated according to the following methods (a) and (b).

(A) Quick-drying property: Electrophotographic paper (product of Xerox Co., Ltd.), bond paper and stock form paper (manufactured by Lion Office Equipment Co., Ltd.) were printed, and after 60 seconds, the printing portion was rubbed with a finger to prevent misalignment of the image. The presence or absence was judged. All of them showed no deviation and showed excellent fixability. (B) Print quality: Each dot printed on the above recording paper was observed with a microscope, and the presence or absence of feathering (whisker-like bleeding) around the dot and the sharpness of the contour were visually evaluated. Both have no feathering,
The contour was also sharp. In addition, the following (c) to (f)
Inkjet recording was evaluated according to the method described in 1.

(C) Long-term storability of recording liquid: The recording liquid was sealed in a glass container and stored at 0 ° C. and 50 ° C. for 1 month. There was no change. (D) Discharge stability: Continuous discharge was performed for 24 hours in each of the atmospheres at room temperature, 5 ° C., and 40 ° C., and stable high-quality recording could be performed from beginning to end under all conditions.

(E) Discharge responsiveness: intermittent discharge every 2 seconds and 2
The discharge after leaving for one month was examined, and in each case, the orifice tip was not clogged, and stable and uniform recording was performed. (F) Quality of recorded image: The recorded image was high in density and clear. The rate of decrease in concentration after exposure to room light for 3 months is 1% or less, and when immersed in water for 1 minute,
Image bleeding was very slight.

Example 2 The yellow ink (2), magenta ink (2), cyan ink (2) and black ink (2) of Reference Example 1
Recording was performed on the color BJ paper LC-101 (manufactured by Canon Inc.) in the same manner as in Example 1 using the above ink.
As a result of evaluating (a) to (f), good results were obtained.

[0043]

According to the present invention, the dyes used in the four color water-based inks of yellow, magenta, cyan and black used in the present invention are all dissolved at the same level in a liquid medium. Due to its excellent stability and storage stability, it is suitable as a general inkjet type water-based ink, and in particular has excellent light resistance, water resistance, vividness, and mutual color rendering in which all dyes are well balanced. Therefore, a color image of excellent quality can be provided.

Claims (1)

[Claims] 1. A method of forming a color image by using an aqueous ink of yellow, magenta, cyan and black by an inkjet method, wherein the free acid form of yellow ink is represented by the following general formula [I] or [II]. An ink containing at least one dye is used and the free acid form of magenta ink is represented by the following general formula [III] or [IV].
An ink containing at least one dye represented by the following formula is used, and the cyan acid ink has a free acid form represented by the following general formula [V].
An ink containing at least one dye represented by the formula
A method for forming a color image, which comprises using an ink containing at least one of the dyes represented by I] and [VII]. Embedded image (In the formula, X, Y, Z and W each independently represent a hydrogen atom, a methyl group, a methoxy group or an ethoxy group, and R is -C ₂
H ₄ OSO ₃ H group, -C ₂ H ₄ OH group or a -CH = CH
Represents ₂ units. ) (In the formula, R has the same meaning as in the above-mentioned general formula [I].) (In the formula, R has the same meaning as in the above-mentioned general formula [I].) (In the formula, V represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R represents the same meaning as in the above general formula [I].) (In the formula, Cu-Pc represents a copper phthalocyanine residue,
l represents an integer of 0 to 3, m represents an integer of 1 to 4, and l + m is an integer of 2 to 4, and R represents the same meaning as in the above general formula [I]. ) [Chemical 6] (In the formula, R has the same meaning as in the above-mentioned general formula [I].) (In the formula, U represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and R represents the same meaning as in the general formula [I].)