Ink formulations, print systems, and methods thereof

• US 20060207473A1
• Filed: 03/17/2005
• Published: 09/21/2006
• Est. Priority Date: 03/17/2005
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Vasudevan, Sundar
• Granted Patent: US 7,300,506 B2
• Time in Patent Office: Days
• US Class Current: 106/31.600
• CPC Class Codes: C08K 3/38 Boron-containing compounds
• CPC Class Codes: C08K 5/17 Amines; Quaternary ammonium compounds
• CPC Class Codes: C08K 5/19 Quaternary ammonium compounds
• CPC Class Codes: C09D 11/38 characterised by non-macromolecular additives other than solvents, pigments or dyes
• CPC Class Codes: C09D 11/40 Ink-sets specially adapted for multi-colour inkjet printing

Abstract

Ink formulations, ink jet sets, methods of stabilizing an ink formulation, printer systems, and methods thereof, are disclosed. One exemplary ink formulation, among others, includes a pigment and a borate buffer. The ink formulation has an ink stability characteristic of a pH drift of less than 1.0 pH over a one year time period. The ink formulation has a size stability characteristic of a diameter of the pigment increasing less than 20% over a one year time period.

Claims

1. An ink formulation, comprising:

a pigment; and

a borate buffer, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one year time period.

2. The ink formulation of claim 1, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 0.5 pH over a one year time period.

3. The ink formulation of claim 1, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 0.2 pH over a one year time period.

4. An ink formulation, comprising:

a pigment; and

a borate buffer, wherein the ink formulation has a size stability characteristic such that a diameter of the pigment increases less than 20% over a one year time period when stored at 23 C.

5. The ink formulation of claim 4, wherein the borate buffer is selected from at least one of:

sodium borate, potassium borate, lithium borate, ammonium borate, tetramethylammonium borate, triethanolamine borate, diethanolamine borate, ethanolamine borate, and combinations thereof.

6. The ink formulation of claim 4, wherein the borate buffer is selected from sodium borate, potassium borate, lithium borate, ammonium borate, and combinations thereof.

7. The ink formulation of claim 4, wherein the borate buffer is selected from triethanolamine borate, diethanolamine borate, ethanolamine borate, and combinations thereof.

8. The ink formulation of claim 4, wherein the borate buffer has an empty frontier orbital energy of about 1.0 eV to −

5 eV.

9. The ink formulation of claim 4, wherein the borate buffer has a pK_a of about 7.5 to about 9.5.

10. The ink formulation of claim 6, wherein the borate buffer has an empty frontier orbital energy of about 1.0 eV to −

5 eV.

11. The ink formulation of claim 4, wherein the pigment is in an amount from about 0.1 to 10 weight percent of the pigment ink formulation;

and

the buffer in an amount from about 0.05 to 8 weight percent of the pigment ink formulation.

12. An ink formulation, comprising:

a pigment; and

a borate buffer, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one year time period, and wherein the ink formulation has a size stability characteristic such that a diameter of the pigment increases less than 20% over a one year time period.

13. The ink formulation of claim 12, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 0.5 pH over a one year time period.

14. The ink formulation of claim 12, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 0.2 pH over a one year time period.

15. The ink formulation of claim 12, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one and a half year time period, and wherein the size stability characteristic has the diameter of the pigment increasing less than 20% over a one and a half year time period.

16. The ink formulation of claim 12, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a two year time period, and wherein the size stability characteristic has the diameter of the pigment increasing less than 20% over a two year time period.

17. An ink-jet ink set, comprising:

a pigment; and

a borate buffer, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one year time period, and wherein the ink formulation has a size stability characteristic such that a diameter of the pigment increasing less than 20% over a one year time period.

18. A method of stabilizing an ink formulation, comprising:

mixing a pigment with a buffer, wherein the buffer causes the ink formulation to have an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one year time period, and wherein the buffer causes the ink formulation to have a size stability characteristic such that a diameter of the pigment increasing less than 20% over a one year time period.

19. A printer system, comprising:

a dispensing system including at least one printhead, wherein the printhead includes an ink formulation, the ink formulation comprising;

a pigment; and

a borate buffer, wherein the ink formulation has an ink stability characteristic such that pH of the ink drifts less than 1.0 pH over a one year time period, and wherein the ink formulation has a size stability characteristic such that a diameter of the pigment increasing less than 20% over a one year time period.