JP2001288392A - Ink set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink sets that can realize the printed images of excellent resistance to light and excellent color reproducibility. SOLUTION: The objective ink set comprises a yellow ink composition, two kinds of magenta ink compositions including the inks having different color darkness and two kinds of cyan ink compositions including inks having different color darkness. In this case, the yellow ink composition includes a compound of general formula I or II as a colorant, the dark magenta ink composition includes a compound of general formula III as a colorant and the light magenta ink composition includes a compound of general formula V as a colorant, and the dark cyan ink composition and the light cyan ink composition include a compound of general formula IV as a colorant, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink set having excellent color reproducibility and light fastness.

2. Description of the Related Art Generally, when an image formed by an ink composition is exposed for a long time to a light beam inside or outside the room or the outside air, it is affected by ultraviolet rays, visible light or various gases in the atmosphere. In many cases, the image deteriorates. In particular, in the case of a color image formed of a plurality of ink compositions, if even one color has poor light resistance, the hue of the image changes and the quality of the color image is extremely deteriorated. For this reason, there is a demand for an ink composition that hardly causes image deterioration even when stored for a long period of time and that can form an image having excellent weather resistance.

[0003] In recent years, an ink jet recording method has attracted attention. The ink jet recording method is a printing method in which small droplets of an ink composition fly and adhere to a recording medium such as paper to perform printing. This method has a feature that high-resolution and high-quality images can be printed at a high speed with a relatively inexpensive device. An ink jet recording apparatus using this method has been widely accepted commercially due to its print quality, low cost, relatively quiet operation, and graphic forming ability. Among them, thermal (bubble jet) and piezoelectric drop-on-demand printers have been particularly successful in the market and have been widely used as printers for personal computers in offices and homes.

Recently, it has been practiced to prepare a plurality of color ink compositions and form a color image by inkjet recording. Generally, the formation of a color image
This is performed by using three colors of a yellow ink composition, a magenta ink composition, and a cyan ink composition, and further, in some cases, four colors including a black ink composition. Further, in some cases, a color image is formed with six colors obtained by adding a light cyan ink composition and a light magenta ink composition to these four colors. The ink composition used to form such a color image, in addition to itself having good color-forming properties, is capable of producing a good intermediate color when combined with a plurality of ink compositions. Is required.

In addition, the ink composition of the ink set used in such an ink jet recording method has, for example, appropriate physical properties such as viscosity and surface tension, a high optical density, and a clear color tone and image. To provide images with excellent robustness such as water resistance, light resistance, etc., to be excellent in storage stability, to be unlikely to cause nozzle clogging, and to further provide safety in terms of odor and fire hazard. Performance is required. To satisfy many of these properties, an aqueous ink in which a water-soluble dye is dissolved in water or a mixture of water and a water-soluble organic solvent is used. At this time,
Different hue ink compositions are prepared from different hue dyes.

Various image characteristics such as color tone, light fastness, and water fastness largely depend on the performance of a colorant in an ink composition, and various dyes have been conventionally studied.

[0007]

SUMMARY OF THE INVENTION The present inventors have now found that an ink set combining a specific dye-based color ink composition can realize an image having extremely excellent color reproducibility and excellent light fastness. Obtained. The present invention is based on such findings. Therefore, an object of the present invention is to provide an ink set capable of realizing an image having excellent color reproducibility.

Accordingly, the ink set of the present invention is an ink set comprising a yellow ink composition, two magenta ink compositions having different color densities, and two cyan ink compositions having different color densities. ,

The yellow ink composition has the following formula (I) or (II) as a coloring agent:

Embedded image

Embedded image Wherein R ₁ , R ₁ ′, R ₂ , and R ₂ ′ independently represent CH ₃ or OCH ₃ , and A and A ′ are

Embedded image Wherein M is H, Li,
It represents Na, K, ammonium or organic amines, and n is an integer of 1 or 2. A compound represented by the formula:

The magenta ink composition having a higher concentration is used as a coloring agent in the following formula (III):

Embedded image [Wherein B and B ′ independently represent H or a group represented by the following formula;

Embedded image(Where B and B 'are not H at the same time)¹Is
C₁~ C₄An alkyl group or an alkoxy group, or
OH, SO ₃M or COOH;²Is O
H, COOM, or NHR⁵And R³Is H
Or C substituted with OH or COOH₁~ C₄No
Represents a alkyl group;⁴Is OH, OCH₃, OC
₂H₅, SO₃M or C substituted with COOM₁~
C₄Represents an alkyl group or a phenyl group;⁵Is
SO₃C substituted with M or COOH₁~ C₄Al
M represents H, Li, Na, K, ammonium
Represents a compound or an organic amine)]].
And

The magenta ink composition having a lower concentration is used as a coloring agent in the following (V):

Embedded image Wherein X represents an anilino group substituted with at least one SO ₃ M, Y represents an OH, Cl, or morpholino group, and M represents H, Li, Na, K, ammonium or an organic amine. Represents a class. A compound represented by the formula:

The cyan ink composition having a higher concentration and the cyan ink composition having a lower concentration are each used as a coloring agent in the following formula (IV):

Embedded image [Wherein, R ⁶ represents OH or COOM;
m and n are each 0 to 4, and (l + m
+ N) = 4].

The ink set according to the present invention can significantly improve the color reproducibility of an image formed by containing a specific compound as a coloring agent of each ink composition, and can improve the color reproducibility of the image. The light resistance can be improved.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Ink Set The ink set according to the present invention is used in a recording system using an ink composition. Examples of the recording method using the ink composition include an ink jet recording method, a recording method using a writing instrument such as a pen, and various other printing methods. The ink composition according to the present invention is preferably used for an ink jet recording method.

The ink set according to the present invention basically includes:
It comprises a yellow ink composition, two types of magenta ink compositions having different color densities, and two types of cyan ink compositions having different color densities. Here, the two types of ink compositions having different color densities can be classified into those having a high density and those having a low density.

Yellow Ink Composition The yellow ink composition used in the present invention comprises a compound represented by the above formula (I) or (II) as a colorant. In the present invention, as a coloring agent,
The compounds represented by the formulas (I) and (II) may be used alone or in combination of two or more.

Specific examples of the compound represented by the formula (I) or (II) include the following.

[0018]

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[0019]

Embedded image

The concentration of the colorant in the yellow ink composition can be appropriately selected, and usually, the ink composition contains the compound represented by the formula (I) or (II) in an amount of 1.5 to 6.
It is preferable to contain 0 wt%. It is preferable that the density is in such a range from the viewpoint of balance with the magenta ink and the cyan ink. Further, since the yellow OD value is preferably in the range of 1.0 to 1.5 when solid printing (solid printing with 100% duty) on so-called plain paper, the yellow ink composition is represented by the formula (I) or ( More preferably, the compound represented by II) is contained in an amount of 1.5 to 4.0% by weight.

Magenta ink composition The two magenta ink compositions having different color densities used in the ink set according to the present invention are referred to as a magenta ink composition having a higher density (hereinafter also referred to as a dark magenta ink as necessary). And a magenta ink composition having a lower concentration (hereinafter, also referred to as a light magenta ink as necessary). By performing inkjet recording using the dark and light magenta ink in this manner, a recorded image having high clarity and excellent light resistance can be obtained.

The darker magenta ink composition used in the present invention comprises the compound represented by the above formula (III) as a colorant. An ink composition containing this compound is excellent in sharpness and light resistance in a single color.

Specific examples of the compound represented by the formula (III) include the following.

[0024]

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[0025]

Embedded image

[0026]

Embedded image

In the present invention, the compound represented by the formula (III) may be used alone or in combination of two or more. The dark magenta ink preferably contains the compound represented by the formula (III) in an amount of 0.5 to 4.0% by weight. When solid printing is performed on so-called plain paper (solid printing with 100% duty), the magenta OD value is in the range of 1.0 to 1.5.

In the present invention, the colorant used in the lower concentration magenta ink composition is a compound represented by the formula (V).

Specific examples of the compound represented by the formula (V) include the following.

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

In the present invention, the compound represented by the formula (V) may be used alone, or two or more kinds may be used in combination.

The concentration of the colorant in the lighter magenta ink composition can be appropriately selected according to the color balance when the above-mentioned dark magenta ink is combined. It is preferable to contain 1 to 3% by weight of the compound represented by (V). By being in such a concentration range, the balance when combined with a dark magenta ink containing the compound represented by the formula (III) is improved.

Cyan Ink Composition The two kinds of cyan ink compositions having different color densities used in the ink set according to the present invention are referred to as a cyan ink composition having a higher density (hereinafter also referred to as a dark cyan ink as necessary). And a cyan ink composition having a lower concentration (hereinafter also referred to as a light cyan ink if necessary).

The dark cyan ink composition and the light cyan ink composition used in the present invention each contain a compound represented by the above formula (IV) as a colorant.

The difference in color density between ink compositions having different color densities may be caused by the magnitude of the dye concentration, or may be caused by appropriately selecting the type of colorant used.

Specific examples of the compound represented by the above formula (IV) include the following.

[0040]

Embedded image

[0041]

Embedded image

In the present invention, as the colorant used in each of the dark cyan ink composition and the light cyan ink composition, the compound represented by the formula (IV) may be used alone, or a plurality of kinds may be mixed and used. May be used.

The concentration of the colorant in the dark cyan ink composition can be appropriately selected, but usually the ink composition contains 2.0 to 6.0% by weight of the compound represented by the formula (IV). Is preferred. Also, when solid printing (so-called 100% Duty solid printing) is performed on so-called plain paper, cyan OD
Since the value is preferably in the range of 1.0 to 1.5,
It is more preferable that the cyan ink composition having a higher concentration contains 2.5 to 4.5% by weight of the compound represented by the formula (IV).

The concentration of the colorant in the light cyan ink composition is appropriately selected according to the color balance when the compound represented by the formula (IV) used as the colorant and the dark cyan ink are combined. In general, the ink composition can be prepared by adding the compound represented by the formula (IV) to 0.4.
It is preferred that the content be 1.5 to 1.5% by weight. By being in such a density range, the balance when combined with the dark cyan ink is improved.

Black Ink Composition In the present invention, an ink set comprising a yellow ink composition, two magenta ink compositions having different color densities, and two cyan ink compositions having different color densities is further provided. A black ink composition can be included.

As the colorant contained in the black ink composition usable in the present invention, any dye or pigment capable of printing black can be used. For example, direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, reactive disperse dyes, etc., are usually ink compositions, especially various dyes used for inkjet recording. Can be used. Further, as such a pigment, a black pigment such as carbon black can be used.

The black ink composition used in the present invention is preferably an aqueous ink from the viewpoint of safety and the like. In the present invention, the dyes contained in the black ink composition can be used alone or in combination of two or more.

Water, water-soluble organic solvents, and other optional
In the ink composition used in the present invention, the main solvent is preferably water or a mixture of water and a water-soluble organic solvent. As the water, pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, or distilled water, or ultrapure water can be used. In addition, it is preferable to use water sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like, since the generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time.

In the ink composition used in the present invention, the content of water when used as a main solvent is preferably from 50 to 90% by weight based on the ink composition, and from 60 to 80% by weight. More preferably, it is% by weight.

According to a preferred embodiment of the present invention, the solvent of the ink composition used in the present invention is a mixture of water and a water-soluble organic solvent, and further comprises a wetting agent comprising a high-boiling organic solvent. Is preferred. Preferred examples of the high-boiling organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, Polyhydric alcohols such as trimethylolethane and trimethylolpropane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n -Butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether,
Triethylene glycol mono-n-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n- Propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl Alkyl ethers of polyhydric alcohols of ether, dipropylene glycol mono-iso-propyl ether Le acids; urea; 2-pyrrolidone,
N-methyl-2-pyrrolidone; 1,3-dimethyl-2-
Examples thereof include imidazolidinone, formamide, acetamide, dimethyl sulfoxide, sorbit, sorbitan, acetin, diacetin, triacetin, and sulfolane, and these can be used alone or in a mixture of two or more.

Preferred specific examples of the acetylene glycol-based surfactant used in the present invention include a compound represented by the following formula (a).

[0052]

Embedded image [In the above formula, 0 ≦ m + n ≦ 50, R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group (preferably having 1 to carbon atoms)
6)

Among the compounds represented by the above formula (a), 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-4-octyne are particularly preferred. -3,6-diol, 3,5-dimethyl-1-hexyn-3-ol and the like. As the acetylene glycol-based surfactant represented by the above formula (a), a commercially available product can also be used, and specific examples thereof include Surfynol 82, 104, 440, 465, 485, and TG (all of which are shown below). Air Products and Chemicals. Inc.
Olfin STG, Olfin E10
10 (trade name) (all manufactured by Nissin Chemical Co., Ltd.).

The addition amount of the surfactant is preferably in the range of about 0.1 to 3% by weight, more preferably in the range of about 0.5 to 2% by weight, based on the ink composition. The surface tension of the ink composition used in the present invention is 45 mN / m.
Or less, and preferably about 25 to 40 mN / m.

The ink composition used in the present invention further comprises a nozzle clogging inhibitor, a preservative or fungicide, an antioxidant, a conductivity adjuster, a pH adjuster, a dissolution aid, a viscosity adjuster, An accelerator, a surface tension adjuster, an oxygen absorber and the like can be added as needed.

Examples of preservatives or fungicides include sodium benzoate, sodium pentachlorophenol,
Sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2
-Dibenzisothiazolin-3-one (Proxel CRL, Proxel BDN, Proxel GX from Zeneca)
L, Proxel XL-2, Proxel TN) and the like.

Further, examples of the pH adjuster, dissolution aid or antioxidant include amines such as diethanolamine, triethanolamine, propanolamine and morpholine, and modified products thereof, potassium hydroxide, sodium hydroxide, Inorganic salts such as lithium hydroxide, ammonium hydroxide, quaternary ammonium hydroxide (such as tetramethylammonium), carbonates such as potassium carbonate, sodium carbonate and lithium carbonate, and other phosphates, and N-methyl-2-pyrrolidone , Urea, thiourea,
Examples thereof include L-ascorbic acid and salts thereof, such as ureas such as tetramethyl urea, allohanates such as allohanate and methyl allohanate, and biurets such as biuret, dimethyl biuret and tetramethyl biuret.

In the present invention, the above-mentioned other optional components can be used alone or as a mixture of a plurality of types in each group and between each group.

In the present invention, the amount of all the components of the ink composition is such that the viscosity of the ink composition is 10 mP at 20 ° C.
Preferably, it is selected to be less than a · s.

Recording Method The ink set according to the present invention is used in a recording system for printing on a recording medium by adhering an ink composition.

According to another aspect of the present invention, there is provided an ink jet recording method for performing printing by discharging droplets of the ink composition contained in the ink set according to the present invention and attaching the droplets to a recording medium. Further, according to the present invention, a recorded matter recorded by these recording methods is also provided.

[0062]

EXAMPLES The present invention will be described below in more detail with reference to examples, but these examples do not limit the scope of the present invention.

[0063] The ink compositions having the compositions represented in the following Table Preparation of Ink set was prepared and create ink set 1-6. In addition, each component amount of the ink shown in the table indicates wt% of each component with respect to the total weight of the ink, and the remaining amount is ion-exchanged water. In addition, dyes Y-1 to Y
-8, M-1 to M-10, LM-1 to LM-12, and C-1 to C-6 mean dyes having the specific structures described above.

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

[Table 3]

[0067]

[Table 4]

[0068]

[Table 5]

[0069]

[Table 6]

Evaluation Test of Ink Set The following ink sets were evaluated for the following tests 1 to 3 using the following recording media (1) to (4). (1) is a so-called plain paper, and (2) to
(4) is a recording medium dedicated to an ink jet printer. (Recording media) (1) Xerox 4024 (manufactured by Xerox Co., USA) (2) EPSON Super Fine Paper (manufactured by Epson Sales Co., Ltd.) (3) EPSON exclusive photo glossy paper (manufactured by Epson Sales Co., Ltd.) (4) EPSON Dedicated glossy film (Epson Sales Co., Ltd.)

In the evaluation test, an ink jet printer PM-770C (manufactured by Seiko Epson Corporation) was used. Further, in the light resistance test, evaluation was performed using a xenon fezaometer Ci35W (manufactured by Atlas Electric Devices Co., Ltd.) as a light resistance acceleration tester.

Test 1 : Light fastness Ink cartridge for PM-770C (Model: IC5C)
L02 manufactured by Seiko Epson Corporation) were filled with the ink sets of Examples and Comparative Examples, and solid printing was performed on the recording media (1) to (4) with red, blue, and green, and a 70% concentration of a combo black. Was. 70% density red is composed of dark magenta, light magenta, and yellow inks, 70% density blue is composed of dark magenta, light magenta, dark cyan, and light cyan inks, and 70% density green is yellow. , Dark cyan, light cyan ink, and 70% density composite black is dark magenta, light magenta, dark cyan, light cyan, yellow,
The printing method was adjusted to be composed of black ink. The black ink used was an original ink for PM-770C.

For the print sample, a xenon featherometer Ci35W (Atlas Electric Co., Ltd.) was used.
(Manufactured by Device Co., Ltd.), a light fastness test for 60 hours was performed, and a color difference (ΔE * ab) before and after the test was obtained from the formula (i), and was determined according to the following criteria. ΔE * ab = [(ΔL *) ² + (Δa *) ² + (Δb *) ² ] ^1/2 (i)

Evaluation A: Color difference ΔE * ab is 5 or less Evaluation B: Color difference ΔE * ab is more than 5 and 10 or less Evaluation C: Color difference ΔE * ab is more than 10 and 20 or less Evaluation D: Color difference ΔE * ab Over 20

The results were as shown in Table 7.

[0076]

[Table 7]

Test 2 : Color reproduction range Each of the ink sets described above was filled in an ink cartridge for PM-770C, and yellow, magenta, cyan, red,
A patch pattern of 100 gradations of each color of blue and green was printed. The brightness of each of the obtained patches (L
*) And hue (a *, b *) are measured, a * is on the X axis, b *, Z is on the Y axis.
By plotting L * on the axis, the three-dimensional space (color reproduction range) of the color was obtained. The color gamut of the original ink set of PM-770C was set to 100%, and was compared with the color gamut of each ink set.

Test 3 : Recovering from clogging Each of the ink sets was filled in a print head of PM-770C, left for 1 month in an environment of 40 ° C. without caps, and after all the nozzles were discharged normally. The number of cleaning operations required until cleaning was performed. The evaluation was made according to the following criteria. Evaluation A: Return within 2 times Evaluation B: Return after 3 to 5 times Evaluation C: Return after 6 to 10 times Evaluation D: No return after 10 operations

The evaluation results of Tests 2 and 3 are as shown in Table 8.

[0080]

[Table 8]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA11 EA13 ED07 EE08 FC02 2H086 BA02 BA53 BA55 BA59 BA62 4J039 BA04 BA29 BC05 BC07 BC09 BC12 BC17 BC19 BC29 BC33 BC36 BC40 BC41 BC52 BC53 BC54 BC60 BC65 BC69 BC73 BC74 BC75 BC77 BC79 BE79 BE02 BE03 BE04 BE05 BE08 BE22 EA15 EA16 EA17 EA19 EA35 GA24

Claims (10)

[Claims] 1. A yellow ink composition having two different color densities.
Magenta ink compositions and two different color densities
An ink set comprising the cyan ink composition of
The yellow ink composition has the following formula (I) or
(II):Embedded image[Where R₁, R₁’, R₂, And R₂’Is independently CH₃
Or OCH₃A and A 'represent the following:Wherein M is H, Li, Na, K, ammonium or an organic
It represents a min and n is an integer of 1 or 2. ]
Magenta ink composition having a higher concentration as a coloring agent.
Formula (III):Wherein B and B ′ are independently H or a group represented by the following formula:
Represents:(However, B and B 'are not H at the same time)¹Is C₁~ C₄Alkyl or alkoxy of
Group, or OH, SO ₃M or COOH;²Is OH, COOM, or NHR⁵Represents R³Is substituted with H, or OH or COOH
C₁~ C₄Represents an alkyl group of⁴Is OH, OCH₃, OC₂H₅, SO₃M or
C substituted with COOM₁~ C₄An alkyl group or
Represents a phenyl group;⁵Is SO₃C substituted with M or COOH₁~ C
₄M represents H, Li, Na, K, ammonium or an organic
Which represents a compound represented by the formula:
Yes, the lighter magenta ink composition is used as a colorant
Note (V):Wherein X is at least one SO₃Anilino substituted with M
Y represents an OH, Cl, or morpholino group; M represents H, Li, Na, K, ammonium or an organic group;
Represents mins. And a compound represented by the formula
Yes, higher density cyan ink composition and lower density
Of the following formula (I)
V):[Where R⁶Represents OH or COOM; l, m, and n are each 0 to 4;
+ M + n) = 4].
What is an ink set. 2. The method according to claim 1, wherein the yellow ink composition has the formula (I) or (I)
The ink set according to claim 1, comprising 1.5 to 4% by weight of the compound represented by (I). (3) a magenta ink composition having a higher concentration,
The magenta ink composition containing the compound represented by the formula (III) in an amount of 0.5 to 4% by weight and having a low concentration is represented by the formula
3. The ink set according to claim 1, comprising 1 to 3% by weight of the compound represented by (V). 4. A method according to claim 1, wherein the cyan ink composition having a higher concentration is represented by the formula:
The cyan ink composition containing 2.5 to 4.5% by weight of the compound represented by the formula (IV) and having a lower concentration is represented by the formula (IV)
Comprising 0.4 to 1.5% by weight of a compound represented by the formula:
The ink set according to claim 1. 5. The composition according to claim 1, further comprising a black ink composition.
The ink set according to claim 1. 6. The ink set according to claim 1, wherein the ink composition further comprises a surfactant. 7. The ink set according to claim 1, which is used in an ink jet recording method. 8. A recording method for printing on a recording medium by adhering an ink composition, wherein the ink composition is used as an ink composition.
A method using the ink composition of the ink set according to any one of claims 1 to 7. 9. An ink jet recording method for performing printing by discharging droplets of an ink composition and attaching the droplets to a recording medium,
An ink jet recording method using the ink composition of the ink set according to any one of claims 1 to 7 as an ink composition. 10. A recorded matter recorded by the method according to claim 8 or 9.