Solvent-based inkjet inks comprising surface-modified pigments
View Patent ↗A solvent-based ink composition for a thermal inkjet printhead comprises a surface-modified pigment. The ink composition comprises: (a) 10-80 wt. % of a compound of formula (A); wherein: R 1 is C 1-6 alkyl; and each of R 2 , R 3 and R 4 is independently selected from H, C 1-6 alkyl, halogen, OH, and C 1-6 alkoxy; (b) 10-80 wt. % of a C 1-6 alcohol; and (c) 0.01-25 wt. % of the surface-modified pigment.
1. A solvent-based ink composition for a thermal inkjet printhead comprising:
(a) 10-80 wt. % of a compound of formula (A);
wherein:
R 1 is C 1-6 alkyl; and
each of R 2 , R 3 and R 4 is independently selected from the group consisting of: H, C 1-6 alkyl, halogen, OH, and C 1-6 alkoxy;
(b) 10-80 wt. % of a C 1-6 alcohol; and
(c) 0.01-25 wt. % of a surface-modified pigment.
2. The ink composition of claim 1 , wherein:
R 1 is C 1-6 alkyl; and
each of R 2 , R 3 and R 4 is H.
3. The ink composition of claim 1 , wherein said compound of formula (A) is N-methyl-2-pyrrolidinone or N-ethyl-2-pyrollidinone.
4. The ink composition of claim 1 , wherein said C 1-6 alcohol is ethanol.
5. The ink composition of claim 1 , wherein said pigment has a surface modified with an anionic or a cationic group.
6. The ink composition of claim 1 , wherein said surface is modified with a carboxylate group or a sulfonate group.
7. The ink composition of claim 1 , comprising 0.001-10 wt. % of a surfactant or dispersant.
8. The ink composition of claim 7 , wherein said surfactant or dispersant is nonionic.
9. The ink composition of claim 1 , wherein said composition does not comprise an acrylate polymer or copolymer.
10. The ink composition of claim 1 , wherein said composition does not comprise any polymers.
11. The ink composition of claim 1 , consisting essentially of said compound of formula (A), said C 1-6 alcohol and said colorant.
12. The ink composition of claim 1 , consisting only of said compound of formula (A), said C 1-6 alcohol and said surface-modified pigment.
13. The ink composition of claim 1 , consisting only of said compound of formula (A), said C 1-6 alcohol, said surface-modified pigment and 0.01-10 wt. % of a surfactant.
14. An ink cartridge for a thermal inkjet printhead, said ink cartridge containing the solvent-based ink composition according to claim 1 .
15. A printhead cartridge comprising thermal inkjet printhead integrated therewith and an ink reservoir containing the ink composition according to claim 1 .
16. A substrate having an ink composition according to claim 1 disposed thereon.
17. The substrate of claim 16 , which is a semi-porous or non-porous substrate.
18. The substrate of claim 16 , which is a vinyl substrate.
19. A method of ejecting ink from a thermal inkjet printhead, said method comprising the steps of:
(i) supplying an ink to at least one nozzle chamber of the printhead; and
(ii) actuating a heater element in the nozzle chamber so as to heat a portion of the ink to a temperature sufficient to form a bubble therein, thereby causing a droplet of ink to be ejected from a nozzle opening associated with the nozzle chamber,
wherein the ink is the solvent-based ink composition according to claim 1 .