JP2008222825A - Ink composition, recording method and recorded matter - Google Patents

Abstract

Disclosed is a black ink composition having excellent color developability on matte paper.
The present invention provides an ink composition containing a dye represented by the following formula (1) as a black color material and having a pH of 11 or more, and a recording method and a recorded matter using the same.
A ₁ -N = NA ₂ -N = NA ₃ (1)
(In the formula (1), A ₁ is a substituent represented by the formula (Bk-2) or (Bk-3) shown in the claims, and A ₂ is a formula (B Bk-4) or a substituent represented by (Bk-5), and A ₃ is a substituent represented by the formula (Bk-6) shown in claims.
[Selection figure] None

Description

  The present invention relates to a black ink composition having excellent color developability on specific paper.

  Conventionally, various ink compositions have been proposed for the purpose of improving the color developability of recorded images.

For example, in Japanese Patent Laid-Open No. 9-255906, for the purpose of providing an ink composition having characteristics such as compatibility between a high-quality image and a water-resistant image, a dye having a specific structure is used as a basis. An ink composition obtained by combining dyes has been proposed (Patent Document 1).
However, the prior art is an invention for a specific color material, and the effect on the color material used in the present invention has not been confirmed. The color material used in the present invention is particularly desired to improve color development on matte paper, and a new color development improvement technique is required.
JP-A-9-255906

  Accordingly, an object of the present invention is to provide an ink composition having excellent color developability on mat paper.

（式（１）中、Ａ₁は下記式（Bｋ-２）又は（Bｋ-３）で表される置換基であり、Ａ₂は下記式（Bｋ-４）又は（Bｋ-５）で表される置換基であり、Ａ₃は下記式（Bｋ-６）で表される置換基である。） The present inventor has achieved the above object by providing the following invention.
1. An ink composition comprising a dye represented by the following formula (1) as a black color material and having a pH of 11 or more.

(In formula (1), A ₁ is a substituent represented by the following formula (Bk-2) or (Bk-3), and A ₂ is represented by the following formula (Bk-4) or (Bk-5). A ₃ is a substituent represented by the following formula (Bk-6).)

（式（Bｋ-２）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-2), M represents Li or Na.)

（式（Bｋ-３）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-3), M represents Li or Na.)

（式（Bｋ-６）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-6), M represents Li or Na.)

2. 2. The ink composition according to 1 above, which contains an inorganic alkali and / or an organic alkali as a pH adjuster.

3. The ink composition according to 2 above, wherein the inorganic alkali is lithium hydroxide and the organic alkali is piperidine.

4). The ink composition according to any one of 1 to 3, further comprising a nonionic surfactant.

5. 5. The ink composition according to 4 above, wherein the nonionic surfactant is an acetylene glycol surfactant.

6). 6. The ink composition according to 4 or 5 above, containing 0.1 to 5% by weight of the nonionic surfactant.

7. The ink composition according to any one of 1 to 6, further comprising a penetration enhancer.

8). 8. The ink composition according to 7 above, wherein the penetration enhancer is a glycol ether.

9. An ink cartridge comprising the ink composition according to any one of 1 to 8 above.

10. An ink jet recording method comprising recording using the ink composition according to any one of 1 to 8 above.

11. A recorded matter recorded using the ink composition according to any one of 1 to 8 above.

  According to the present invention, it is possible to provide an ink composition having excellent color developability on matte paper. Further, a recorded matter having excellent color developability can be obtained by the recording method using the ink composition of the present invention.

  Hereinafter, the ink composition according to the present invention will be described based on preferred embodiments thereof.

  The ink composition of the present invention contains a dye represented by the following formula (1) as a black color material, and has a pH of 11 or more.

（式（１）中、Ａ₁は下記式（Bｋ-２）又は（Bｋ-３）で表される置換基であり、Ａ₂は下記式（Bｋ-４）又は（Bｋ-５）で表される置換基であり、Ａ₃は下記式（Bｋ-６）で表される置換基である。）

(In formula (1), A ₁ is a substituent represented by the following formula (Bk-2) or (Bk-3), and A ₂ is represented by the following formula (Bk-4) or (Bk-5). A ₃ is a substituent represented by the following formula (Bk-6).)

（式（Bｋ-２）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-2), M represents Li or Na.)

（式（Bｋ-３）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-3), M represents Li or Na.)

（式（Bｋ-６）中、ＭはＬｉ又はＮａを表す。）

(In the formula (Bk-6), M represents Li or Na.)

  The ink composition of the present invention has such a configuration, and can form an image excellent in color developability on mat paper.

  First, the dye represented by the formula (1) as the black color material used in the present invention will be described.

As the dye represented by the formula (1), specifically, the formula (1):
The A ₁ to A ₃ in _{A 1 -N = N-A 2} -N = N-A 3 combined as shown in Table 1, the following formula (Bk-1-1), the formula (Bk-1-2) , (Bk-1-3), and a colorant as shown in Formula (Bk-1-4). These colorants may be used alone or in combination of two or more.

表１中、ＭはＬｉ又はＮａを示す。

In Table 1, M represents Li or Na.

  As described above, the pH of the ink composition of the present invention is 11.0 or higher (at 20 ° C.), and particularly preferably 12 or higher. By setting the pH of the ink composition at 20 ° C. to 11.0 or higher, the color development on the matte paper, which is the effect of the present invention, can be sufficiently enhanced, and by setting it to 12 or higher, further effects can be achieved. .

The ink composition of the present invention preferably contains an inorganic alkali and / or an organic alkali as a pH adjuster in order to obtain a desired pH value of 11 or more.
Examples of the inorganic alkali include metal hydroxides such as potassium hydroxide, sodium hydroxide and lithium hydroxide, ammonium salts such as ammonium hydroxide and quaternary ammonium hydroxide (tetramethylammonium etc.), potassium carbonate, sodium carbonate, Examples of the organic alkali include, but are not limited to, amines such as piperidine, diethanolamine, triethanolamine, propanolamine, and morpholine, and modified products thereof. .
Especially, it is preferable at the point of the improvement effect with respect to the black color material used by this invention that the said inorganic alkali is lithium hydroxide and the said organic alkali is piperidine.

  The ink composition of the present invention preferably contains 5 to 8% by weight of the black color material, and preferably contains 1 to 5% by weight of the inorganic alkali and / or organic alkali.

Hereinafter, other components contained in each ink composition will be described.
The ink composition in the present invention can be obtained by dissolving the above-described black color material and, if necessary, an inorganic alkali and / or an organic alkali in an appropriate solvent. As the solvent for dissolving these components in the ink composition of the present invention, it is preferable to use water or a mixed liquid of water and a water-soluble organic solvent as a main solvent. As water, ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or the like can be used. From the viewpoint of long-term storage, it is preferable to use water that has been subjected to various chemical sterilization treatments such as ultraviolet irradiation and addition of hydrogen peroxide. The water content in the ink composition of the present invention is preferably 40 to 90% by weight of the ink composition, and more preferably 50 to 80% by weight.

  As described above, the ink composition in the present invention can use a water-soluble organic solvent as a solvent together with water. As the water-soluble organic solvent, those having the ability to dissolve the dye are preferable, and those having a vapor pressure smaller than that of pure water are preferable.

  Examples of the water-soluble organic solvent that can be used in the present invention include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, 2-butene-1,4-diol, and 2-methyl-2,4-pentane. Diol, glycerin, 1,2,6-hexanetriol, polyhydric alcohols such as diethylene glycol, triethylene glycol and dipropylene glycol, ketones such as acetonyl acetone, esters such as γ-butyrolactone and triethyl phosphate, Furyl alcohol, tetrahydrofurfuryl alcohol, thiodiglycol and the like are preferable, but are not limited thereto. By using a water-soluble organic solvent together with water as the solvent of the ink composition, the ejection stability of the ink composition from the ink head can be improved, and the viscosity of the ink composition can be increased with almost no other changes. Etc. can be easily adjusted.

  In addition, at least one humectant selected from saccharides can be contained in the ink composition of the present invention. By including a moisturizing agent in the ink composition, when the ink composition is used in the ink jet recording method, it is possible to suppress moisture evaporation from the ink and moisturize the ink. As the saccharide used in the present invention, maltitol, sorbitol, gluconolactone, maltose and the like are preferable. In addition, the water-soluble organic solvent mentioned above may work as a moisturizer.

  The water-soluble organic solvent and / or humectant can be contained in the ink composition in a total amount of 5 to 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 5 to 20% by weight. By making these contents 5% by weight or more, good ink moisture retention can be obtained, and by making it 50% by weight or less, the viscosity of the ink composition is adjusted to a preferred viscosity for use in the ink jet recording method. can do.

Other preferable additives to be added to the ink composition of the present invention will be described below.
The ink composition of the present invention preferably contains a nonionic surfactant. By adding a nonionic surfactant, the penetrability of the ink composition into the recording medium is improved, and the ink composition can be quickly fixed on the recording medium during printing. Further, it is preferable that one dot recorded by the ink composition on the recording medium is as close to a perfect circle as possible. However, by containing a nonionic surfactant in the ink composition, an image formed by one dot It is possible to increase the roundness and improve the image quality of the obtained image.

  As a nonionic surfactant that can be used in the present invention, for example, an acetylene glycol-based surfactant is preferable, but is not limited thereto. As the acetylene glycol surfactant used in the ink composition of the invention, in particular, the following formula (a-1):

（式（ａ-１）中、Ｒ¹、Ｒ²、Ｒ³、及びＲ⁴はそれぞれ独立して、Ｃ１〜Ｃ６の直鎖、環式又は分枝アルキル鎖を表し、さらにＡ¹Ｏ及びＡ²Ｏはそれぞれ独立してＣ２〜Ｃ３のオキシアルキレン鎖、例えばオキシエチレン若しくはオキシプロピレン、又はＣ２〜Ｃ３のアルキレンオキサイドが重合又は共重合して得られるポリオキシアルキレン鎖、例えばポリオキシエチレン鎖、ポリオキシプロピレン鎖、若しくはポリオキシエチレンプロピレン鎖を表す。また式中、ｎ及びｍはＡ¹Ｏ又はＡ²Ｏ単位、すなわちオキシアルキレンの繰り返し数を表し、０≦ｎ＜３０、０≦ｍ＜３０、及び０≦ｎ＋ｍ＜５０を満たす数である。）
で表される化合物を用いることが好ましい。このアセチレングリコール系界面活性剤としては、例えば、サーフィノール４６５（商標）、サーフィノール１０４（商標）（以上商品名、Air Products and Chemicals Inc.製）、オルフィンＰＤ００１（商標）、オルフィンＥ１０１０（商標）（以上商品名、日信化学工業株式会社製）を例示することができ、これらから選ばれる少なくとも一種を本発明のインク組成物に添加することが好ましい。

(In Formula (a-1), R ¹ , R ² , R ³ , and R ⁴ each independently represent a C1-C6 straight chain, cyclic, or branched alkyl chain, and A ¹ O and A ² O is each independently a C2-C3 oxyalkylene chain, such as oxyethylene or oxypropylene, or a polyoxyalkylene chain obtained by polymerization or copolymerization of C2-C3 alkylene oxide, such as a polyoxyethylene chain, a polyoxyethylene chain, Represents an oxypropylene chain or a polyoxyethylenepropylene chain, wherein n and m represent A ¹ O or A ² O units, that is, the number of repeating oxyalkylenes, and 0 ≦ n <30, 0 ≦ m <30 And 0 ≦ n + m <50.)
It is preferable to use the compound represented by these. Examples of the acetylene glycol-based surfactant include Surfynol 465 (trademark), Surfynol 104 (trademark) (trade name, manufactured by Air Products and Chemicals Inc.), Olfine PD001 (trademark), Olfine E1010 (trademark). (The above trade name, manufactured by Nissin Chemical Industry Co., Ltd.) can be exemplified, and it is preferable to add at least one selected from these to the ink composition of the present invention.

  In the present invention, the nonionic surfactant is contained in the ink composition so that the nonionic surfactant is preferably contained in the ink composition in an amount of 0.1 to 5% by weight, more preferably 0.5 to 2% by weight. An agent should be added. By including 0.1% by weight or more of a nonionic surfactant in the ink composition, the penetrability of each ink composition with respect to the recording medium can be increased. Further, by making the content of the nonionic surfactant in the ink composition 5% by weight or less, an effect that an image formed with the ink composition on the recording medium is difficult to blur can be obtained.

  Furthermore, in addition to nonionic surfactants, the addition of glycol ethers as penetration enhancers to the ink composition improves the penetrability of the ink composition with respect to the recording medium, and when color printing is performed. At the boundary between adjacent color inks, ink bleeding (bleeding) is reduced, and a very clear image can be obtained. Therefore, it is preferable to add a penetration enhancer to the ink composition of the present invention.

  Examples of the glycol ethers that can be used in the present invention as a penetration enhancer include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and propylene glycol monobutyl ether. , Dipropylene glycol monobutyl ether, triethylene glycol monobutyl ether and the like are preferable, but are not limited thereto. These glycol ethers are preferably contained in the ink composition in an amount of 3 to 30% by weight, more preferably 5 to 15% by weight. By making the addition amount of glycol ethers 3% by weight or more, bleeding between adjacent inks during color printing can be effectively prevented, and by making this addition amount 30% by weight or less, image It becomes easy to prevent the occurrence of bleeding, and the storage stability of the ink can be improved.

  Further, the ink composition of the present invention includes a water-soluble polymer such as sodium alginate, a water-soluble resin, a fluorosurfactant, an antiseptic, a fungicide, a rust inhibitor, a dissolution aid, an antioxidant, and an ultraviolet ray. A material selected from an absorbent and the like can be added as desired. These components can be used alone or in combination of two or more. Moreover, it is not necessary to add, if it is not necessary to add. Those skilled in the art can use the preferable additive selected in a preferable amount as long as the effects of the present invention are not impaired. The dissolution aid is an additive for dissolving the insoluble matter and keeping the ink composition in a uniform solution when the insoluble matter is precipitated from the ink composition.

  Examples of the solubilizer include pyrrolidones such as N-methyl-2-pyrrolidone and 2-pyrrolidone, ureas such as urea, thiourea and tetramethylurea, allophanates such as allohanate and methyl allophanate, biuret and dimethylbiuret. And biurets such as tetramethylbiuret can be mentioned, but the invention is not limited to these. Moreover, as an example of the said antioxidant, although L-ascorbic acid and its salt etc. can be illustrated, it is not limited to these.

  Examples of the antiseptic or antifungal agent include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzisothiazoline-3. -On (Arch Chemicals) Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN (trade name) and the like can be exemplified, but are not limited thereto.

  The ink composition of the present invention is prepared by including components appropriately selected from the components described above, and the viscosity of the obtained ink composition is preferably less than 10 mPa · s at 20 ° C. Furthermore, in the present invention, the surface tension of the ink composition is preferably 45 mN / m or less at 20 ° C., and particularly preferably in the range of 25 to 45 mN / m. By adjusting the viscosity and the surface tension in this way, an ink composition having desirable characteristics for use in the ink jet recording method can be obtained. The adjustment of the viscosity and the surface tension can be performed by appropriately adjusting and selecting the addition amount of the solvent and various additives to be contained in the ink composition, the kind thereof, and the like.

  As a method for preparing the ink composition in the present invention, for example, various components contained in the ink composition are sufficiently mixed and dissolved as uniformly as possible, followed by pressure filtration with a membrane filter having a pore size of 0.8 μm, and further. Although the method of preparing the obtained solution by deaeration using a vacuum pump can be illustrated, it is not limited to this.

  Next, the ink composition described above can be used as one or two or more ink sets as an ink cartridge housed integrally or independently, and is preferable from the viewpoint of convenient handling. Ink cartridges comprising an ink composition are known in the art, and can be made into ink cartridges by appropriately using known methods.

  The ink cartridge using the ink composition of the present invention can be used for general writing instruments, recorders, pen plotters, and the like, but is particularly preferably used for an ink jet recording method. The ink jet recording method in which the ink cartridge can be used includes any recording method in which the ink composition is ejected as droplets from a thin nozzle and the droplets are attached to a recording medium. Specific examples of the ink jet recording method in which the ink composition of the present invention can be used will be described below.

  The first method is a method called an electrostatic attraction method. In the electrostatic suction method, a strong electric field is applied between the nozzle and the acceleration electrode arranged in front of the nozzle, and droplet-like ink is continuously ejected from the nozzle, and the ink droplet passes between the deflection electrodes. In the meantime, by supplying a printing information signal to the deflection electrode, the ink droplets are blown toward the recording medium and the ink is fixed on the recording medium, or the image is recorded, or the ink droplets are not deflected, In this method, an image is fixed on a recording medium by ejecting ink droplets from a nozzle onto the recording medium in accordance with a print information signal. The ink composition of the present invention is preferably used in a recording method using this electrostatic suction method.

  The second method is a method for forcibly ejecting ink droplets from the nozzles by applying pressure to the ink liquid with a small pump and mechanically vibrating the ink jet nozzles with a quartz vibrator or the like. The ink droplet ejected from the nozzle is charged at the same time as it is ejected, and while the ink droplet passes between the deflection electrodes, a print information signal is given to the deflection electrode to fly the ink droplet toward the recording medium, This is a method for recording an image on a recording medium. The ink composition of the present invention is preferably used in this recording method.

  The third method is a method in which an image is recorded on a recording medium by simultaneously applying a pressure and a printing information signal to the ink liquid by a piezoelectric element, and ejecting ink droplets from a nozzle toward the recording medium. The ink set or ink cartridge of the present invention is preferably used for this recording method.

  In the fourth method, the ink liquid is heated and foamed using microelectrodes according to the print signal information, and the bubbles are expanded to eject the ink liquid from the nozzle toward the recording medium, thereby forming an image on the recording medium. It is a method of recording. The ink composition of the present invention is preferably used in this recording method.

  The ink composition of the present invention is particularly preferred as an ink composition used when an image is recorded on a recording medium, preferably on matte paper, using an image recording method based on an ink jet recording method including the four methods described above. The recorded matter recorded using the ink composition of the present invention has excellent image quality, particularly color developability.

〔Example〕
Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

  Ink compositions shown in Table 2 were prepared according to a conventional method.

  In the table, Bk1: Black dye 1 is an example of the compound represented by the formula (1), and the following formula (H):

And A _{1 to} A ₃ in Black Dye 1 are groups shown below.

で表される化合物であるY1：Yellow（イエロー） 染料１を用いた。 Further, as a dye for color tone adjustment in the black ink composition, the following formula (J):

Y1: Yellow (yellow) dye 1 which is a compound represented by the formula:

Evaluation test <Color development>
Using the above-described cartridge filled with black ink, the ink-jet recording medium “Photomat Paper: Model No. KA450PM (manufactured by Seiko Epson Corporation)” has a printing amount of 1.5 to 2.2 mg per centimeter square meter. Solid printing was performed with the monochrome print setting specified on the printer driver.
The OD value of each printed matter was measured using a densitometer (Spectroino: manufactured by Gretag).

The criteria for color development were determined as follows.
A: OD value 1.65 or more B: OD value 1.60 or more and less than 1.65 C: OD value less than 1.60

The evaluation results are shown in the following table.

  INDUSTRIAL APPLICABILITY The present invention has industrial applicability as an ink composition having excellent color developability on matte paper, a recording method using the ink composition, and a recorded matter.

Claims (11)

An ink composition comprising a dye represented by the following formula (1) as a black color material and having a pH of 11 or more.

(In formula (1), A ₁ is a substituent represented by the following formula (Bk-2) or (Bk-3), and A ₂ is represented by the following formula (Bk-4) or (Bk-5). A ₃ is a substituent represented by the following formula (Bk-6).)

(In the formula (Bk-2), M represents Li or Na.)

(In the formula (Bk-3), M represents Li or Na.)

(In the formula (Bk-6), M represents Li or Na.)   The ink composition according to claim 1, comprising an inorganic alkali and / or an organic alkali as a pH adjuster.   The ink composition according to claim 2, wherein the inorganic alkali is lithium hydroxide and the organic alkali is piperidine.   The ink composition according to any one of claims 1 to 3, further comprising a nonionic surfactant.   The ink composition according to claim 4, wherein the nonionic surfactant is an acetylene glycol surfactant.   The ink composition according to claim 4, comprising 0.1 to 5% by weight of the nonionic surfactant.   Furthermore, the ink composition as described in any one of Claims 1-6 containing a penetration enhancer.   The ink composition according to claim 7, wherein the penetration enhancer is a glycol ether.   An ink cartridge comprising the ink composition according to any one of claims 1 to 8.   An ink jet recording method comprising recording using the ink composition according to any one of claims 1 to 8.   A recorded matter recorded using the ink composition according to claim 1.