Granted Patent B1

US 9,434,848 · App. 14/635,679 · Granted Sep 6, 2016

Abstract

Claims (39)

1. A process black ink composition for digital offset printing comprising:

a cyan colorant comprising a cyan pigment,

a magenta colorant comprising a magenta pigment and

a yellow colorant comprising a yellow pigment,

wherein the process black ink composition comprises a total amount of pigment of at least about 15 wt %,

a photo-initiator,

a dispersant, and

a curable ink vehicle component comprising at least one component selected from the group consisting of a curable monomer and a curable oligomer;

wherein the process black ink composition comprises a ratio of the cyan colorant to the yellow colorant of 0.70-0.80:1.0 and a ratio of the magenta colorant to the yellow colorant of 0.90-0.80:1.0, wherein the process black ink composition does not comprise carbon black, and wherein the process black ink further comprises a filler.

2. The process black ink composition of claim 1 , wherein the process black ink further comprises a stabilizer.

3. The process black ink composition of claim 1 , wherein the cyan colorant comprises Pigment Blue 15:3, the magenta colorant comprises Pigment Red 57:1 and the yellow colorant comprises a pigment selected from the group consisting of Pigment Yellow 14 and Pigment Yellow 13.

4. The process black ink composition of claim 3 , wherein the ratio of the cyan colorant comprising Pigment Blue 15:3 to the yellow colorant comprising the yellow pigment is 0.76:1 and wherein the ratio of the magenta colorant comprising the Pigment Red 57:1 to the yellow colorant comprising the yellow pigment is 0.80:1.0.

5. The process black ink composition of claim 1 , wherein the process black ink composition is transferable to a printable substrate from an imaging member at an efficiency of 90% or greater.

6. A method of preparing a process black ink composition, the method comprising:

a) providing a cyan colorant comprising a cyan pigment, a magenta colorant comprising a magenta pigment and a yellow colorant comprising a yellow pigment, wherein a ratio of the cyan colorant to the yellow colorant is 0.70-0.80:1.0 and a ratio of the magenta colorant to the yellow colorant is 0.90-0.80:1.0,

b) acoustically mixing the colorants;

c) acoustically mixing a photo-initiator; a dispersant and at least one curable ink vehicle component selected from the group consisting of a monomer and an oligomer with the acoustically mixed colorants to form a curable ink mixture,

d) milling the curable ink mixture formed in c) to obtain a process black ink composition, wherein the process black ink composition does not comprise carbon black.

7. The method of claim 6 , wherein the cyan colorant comprises Pigment Blue 15:3, the magenta colorant comprises Pigment Red 57:1 and the yellow colorant comprises a pigment selected from the group consisting of Pigment Yellow 14 and Pigment Yellow 13.

8. The method of claim 7 , wherein the ratio of the cyan colorant comprising Pigment Blue 15:3 to the yellow colorant comprising the yellow pigment is 0.76:1 and wherein the ratio of the magenta colorant comprising Pigment Red 57:1 to the yellow colorant comprising the yellow pigment is 0.80:1.0.

9. The process of claim 6 , further comprising heating and stirring the curable ink mixture formed in c) before milling.

10. The method of claim 6 , wherein the curable ink mixture formed in c) further comprises a stabilizer.

11. The method of claim 6 , wherein the curable ink mixture formed in c) further comprises a filler.

12. A method of halftone printing, the method comprising:

providing a cyan ink composition, a magenta ink composition and a yellow ink composition,

applying the cyan ink composition, the magenta ink composition and the yellow ink composition onto a re-imageable imaging member surface, wherein a ratio of the cyan ink composition to the yellow ink composition is 0.70-0.80:1.0 and a ratio of the magenta ink composition to the yellow ink composition is 0.90-0.80:1.0;

forming an ink image;

transferring the ink image from the re-imageable surface of the imaging member onto a printable substrate to form a halftone black image;

wherein the halftone black image does not comprise carbon black,

wherein the cyan ink composition comprises at least about 15% by weight of a cyan pigment, the magenta ink composition comprises at least about 15% by weight of a magenta pigment and the yellow ink composition comprises at least about 15% by weight of a yellow pigment,

and wherein said cyan ink composition, said magenta ink composition and said yellow ink composition each further comprises:

a photo-initiator,

a dispersant, and

a curable ink vehicle component comprising at least one component selected from the group consisting of a curable monomer and a curable oligomer.

13. The method of claim 12 , wherein the transferring of the ink image from the re-imageable surface of the imaging member onto a printable substrate is at an efficiency of 90% or greater.

14. The method of claim 12 , wherein the method further comprises partially curing the cyan, magenta and yellow ink compositions after applying the cyan, magenta and yellow ink compositions onto a re-imageable imaging member surface.

15. The method of claim 14 , wherein the transferring of the ink image from the re-imageable surface of the imaging member onto a printable substrate is at an efficiency of 98% or greater.

16. The method of claim 12 , wherein the cyan ink composition comprises Pigment Blue 15:3, the magenta ink composition comprises Pigment Red 57:1 and the yellow ink composition comprises a yellow pigment selected from the group consisting of Pigment Yellow 14 and Pigment Yellow 13.

17. The method of claim 16 , wherein the ratio of the cyan ink composition comprising the Pigment Blue 15:3 to the yellow ink composition comprising the yellow pigment is 0.76:1 and wherein the ratio of the magenta ink composition comprising the Pigment Red 57:1 to the yellow composition comprising the yellow pigment is 0.80:1.0.

Assignments (10)