Ink compositions

Patent metadata

Field	Value
Publication number	US-10072167-B2
Application number	US-201715834803-A
Country	US
Kind code	B2
Filing date	Dec 7, 2017
Priority date	May 13, 2016
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

An ink composition includes a fluid and a plurality of microcapsules suspended in the fluid. The fluid includes a first chemical compound that exhibits a first color characteristic in a first pH range and exhibits a second color characteristic in a second pH range, where the first color characteristic is visually distinct from the second color characteristic. A second chemical compound is contained within the microcapsules, such that rupturing at least a subset of the plurality of microcapsules releases the second chemical compound. Releasing the second chemical compound shifts a pH of the fluid from a first pH in the first pH range to a second pH in the second pH range.

First claim

The invention claimed is:

1. An ink composition comprising:
a fluid including a first chemical compound that exhibits a first color characteristic in a first pH range and exhibits a second color characteristic in a second pH range, the first color characteristic visually distinct from the second color characteristic;
a plurality of microcapsules suspended in the fluid and configured to rupture upon application of energy to the microcapsules; and
a second chemical compound contained within the microcapsules, wherein rupturing at least a subset of the plurality of microcapsules to release the second chemical compound shifts a pH of the fluid from a first pH in the first pH range to a second pH in the second pH range.

2. The ink composition of claim 1 , wherein the first chemical compound is colored when exhibiting the first color characteristic and is substantially colorless when exhibiting the second color characteristic.

3. The ink composition of claim 1 , wherein the first chemical compound includes phenolphthalein.

4. The ink composition of claim 1 , wherein the first chemical compound includes cresolphthalein.

5. The ink composition of claim 1 , wherein the first chemical compound includes thymolphthalein.

6. The ink composition of claim 1 , wherein the fluid includes a solvent and a pH buffer compound selected to cause the fluid to have the first pH while the microcapsules are intact.

7. The ink composition of claim 1 , wherein the second chemical compound is an acid.

8. The ink composition of claim 1 , wherein the second chemical compound is a base.

9. The ink composition of claim 1 , wherein the microcapsules are configured to rupture when abraded.

10. The ink composition of claim 1 , wherein each microcapsule includes a polymer shell encapsulating a portion of the second chemical compound.

11. The ink composition of claim 1 , wherein the plurality of microcapsules have a mean characteristic dimension of less than 10 μm.

12. A marking implement comprising:
a tip;
a fluid reservoir coupled to the tip; and
an ink composition within the fluid reservoir, the ink composition comprising:
a fluid including a first chemical compound that exhibits a first color characteristic in a first pH range and exhibits a second color characteristic in a second pH range, the first color characteristic visually distinct from the second color characteristic;
a plurality of microcapsules suspended in the fluid and configured to rupture upon application of energy to the microcapsules; and
a second chemical compound contained within the microcapsules, wherein rupturing at least a subset of the plurality of microcapsules to release the second chemical compound shifts a pH of the fluid from a first pH in the first pH range to a second pH in the second pH range.

13. The marking implement of claim 12 , wherein the first chemical compound is colored when exhibiting the first color characteristic and is substantially colorless when exhibiting the second color characteristic.

14. The marking implement of claim 12 , wherein the fluid includes a solvent and a pH buffer compound selected to cause the fluid to have the first pH while the microcapsules are intact.

15. The marking implement of claim 12 , wherein the microcapsules are configured to rupture when abraded.

16. The marking implement of claim 12 , wherein the plurality of microcapsules have a mean characteristic dimension of less than 10 μm.

17. A method of changing a color characteristic of an ink composition, the method comprising, after an ink composition has been applied to a surface, the ink composition comprising:
a fluid including a first chemical compound that exhibits a first color characteristic in a first pH range and exhibits a second color characteristic in a second pH range, the first color characteristic visually distinct from the second color characteristic; and
a plurality of microcapsules suspended in the fluid; and
a second chemical compound contained within the microcapsules:
by applying energy to the surface, rupturing at least a subset of microcapsules of the plurality of microcapsules to release the second chemical compound, wherein the second chemical compound, when released, shifts the pH of the fluid from a first pH in the first pH range to a second pH in the second pH range.

18. The method of claim 17 , wherein rupturing at least the subset of microcapsules comprises abrading the surface.

19. The method of claim 17 , wherein shifting the pH of the fluid causes the ink composition to change from a first color to a second color.

20. The method of claim 17 , wherein shifting the pH of the fluid causes the ink composition to change from colored to substantially colorless.

Assignees

• IBM

Inventors

• Kuczynski Joseph
• Misgen Marvin M
• Neuman-Horn Debra A
• Prisco Joseph F
• Przybylski Kevin J

Classifications

• B43K29/05

  with applicators for eradicating- or correcting-liquid · CPC title

• C09D11/17 Primary

  characterised by colouring agents · CPC title

• B41M2205/24

  Reactive compound reacting in image receiving layer other than leuco dyes or mordants · CPC title

• B41M5/287

  using microcapsules or microspheres only · CPC title

• C09D11/54

  Inks based on two liquids, one liquid being the ink, the other liquid being a reaction solution, a fixer or a treatment solution for the ink · CPC title