Black water-based ink composition

• US 20050126435A1
• Filed: 11/22/2004
• Published: 06/16/2005
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kitamura, Kazuhiko, Hanmura, Masahiro, Aoyama, Tetsuya
• Granted Patent: US 7,094,279 B2
• Time in Patent Office: Days
• US Class Current: 106/31.460
• CPC Class Codes: C09D 11/328 characterised by dyes
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

The present invention provides a black water-based ink composition that has excellent resistance to light and ozone, has an excellent hue as a black ink, and also has excellent storage stability. A black water-based ink composition is prepared by combining at least one type of black dye selected from the group consisting of compounds expressed by the following formula (1) and salts thereof:

and at least one type of dye other than a black dye, and the hue is adjusted by adding the dye other than a black dye. It is preferable if the dye other than the black dye is a compound that has at least one type of group selected from the group consisting of an —SO₃H group, —COOH group, —SO₃M group, and —COOM group (where M in these groups is an alkali metal atom), and is not an ammonium salt or a salt with an organic cation. It is also preferable for the dye other than the black dye to be a dye selected from the group consisting of yellow dyes and magenta dyes.

Claims

1. A black water-based ink composition, containing:

at least one type of black dye selected from the group consisting of compounds expressed by the following formula (1) and salts thereof;

(in the formula (1), R¹ is a phenyl group having a substituent or a naphthyl group having a substituent, R² is a phenylene group having a substituent or a naphthylene group having a substituent, R³ is a 5- to 7-member heterocyclic group having a substituent and at least one double bond, and the substituents in R¹ to R³ are independently selected from the group consisting of OH, SO₃H, PO₃H₂, CO₂H, NO₂, C₁ to C₄ alkyl groups, alkyl groups having a substituent, C₁ to C₄ alkoxy groups, alkoxy groups having a substituent, amino groups having a substituent, and phenyl groups having a substituent),

and at least one type of dye other than said black dye,

wherein the hue is adjusted by adding the dye other than the black dye.

2. The black water-based ink composition according to claim 1, wherein the compound expressed by the formula (1) is a compound expressed by the following formula (2)

3. The black water-based ink composition according to claim 1, wherein the dye other than the black dye is a compound that has at least one type of group selected from the group consisting of an —

SO₃H group, —

COOH group, —

SO₃M group, and —

COOM group (where M in these groups is an alkali metal atom), has no primary amino group, and is not an ammonium salt or a salt with an organic cation.

4. The black water-based ink composition according to claim 3, wherein the at least one type of dye other than the black dye is a dye selected from the group consisting of yellow dyes and magenta dyes.

5. The black water-based ink composition according to claim 3, wherein at least a yellow dye and a magenta dye are included as the dye other than the black dye.

6. The black water-based ink composition according to claim 4, wherein the yellow dye is at least one type selected from the group consisting of compounds expressed by the following formula (3):

7. The black water-based ink composition according to claim 4, wherein the magenta dye is at least one type selected from the group consisting of compounds expressed by the following formula (5) and alkali metal salts thereof:

8. The black water-based ink composition according to claim 7, wherein the compounds expressed by the formula (5) and alkali metal salts thereof are compounds expressed by the following formula (6) and alkali metal salts thereof:

9. The black water-based ink composition according to claim 5, wherein the yellow dye is at least one type selected from the group consisting of compounds expressed by the formula (3) and compounds expressed by the formula (4), and the magenta dye is at least one type selected from the group consisting of compounds expressed by the formula (5) and alkali metal salts thereof, compounds expressed by the formula (6) and alkali metal salts thereof, and C.I. Direct Red 227.

10. The black water-based ink composition according to claim 1, wherein the black dye is contained in an amount of 0.5 to 12.0 wt % with respect to the total weight of the black water-based ink composition.

11. The black water-based ink composition according to claim 4, wherein the black dye is contained in an amount of 0.5 to 12.0 wt % with respect to the total weight of the black water-based ink composition.

12. The black water-based ink composition according to claim 4, wherein the yellow dye is contained in an amount of 0.03 to 3.0 wt % with respect to the total weight of the black water-based ink composition.

13. The black water-based ink composition according to claim 4, wherein the magenta dye is contained in an amount of 0.02 to 3.0 wt % with respect to the total weight of the black water-based ink composition.

14. The black water-based ink composition according to claim 6, wherein the black dye and the yellow dye are contained in a weight ratio between 15:

1 and 10;

3.

15. The black water-based ink composition according to claim 7, wherein the black dye and the magenta dye are contained in a weight ratio between 25:

1 and 10;

3.

16. An inkjet recording method, wherein the black water-based ink composition according to claim 1 is discharged in the form of droplets from a narrow nozzle, and these droplets are made to adhere to a recording medium.

17. Recorded material, which has been printed by the inkjet recording method according to claim 16.