Phase change inks containing colorant compounds

1. A phase change ink composition comprising a phase change ink carrier and a colorant compound of the formula

wherein R 1 , R 2 , R 3 , and R 4 each, independently of the others, is (i) a hydrogen atom, (ii) an alkyl group, (iii) an aryl group, (iv) an arylalkyl group, or (v) an alkylaryl group, wherein R 1 and R 2 can be joined together to form a ring, wherein R3 and R 4 can be joined together to form a ring, and wherein R 1 , R 2 , R 3 , and R 4 can each be joined to a phenyl ring in the central structure;

wherein a and b each, independently of the others, is an integer which is 0, 1, 2, or 3,

wherein R 5 and R 6 are hydrogen or alkyl;

wherein A is an anion;

wherein CA is either a hydrogen atom or a cation;

wherein R is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, (iv) an alkylaryl group, (v) an alkoxy group, (vi) an acetate group, or (vii) a co-polymer of maleic anhydride;

wherein n is an integer which is about 1 to about 1,000; and

wherein m is an integer which is about 1 to about 1,000.

2. A phase change ink composition according to claim 1 , wherein the phase change ink carrier comprises a monoamide, a tetra-amide, or a mixture thereof.

3. A phase change ink composition according to claim 1 , wherein the phase change ink carrier comprises (a) stearyl stearamide, (b) a dimer acid based tetra-amide that is the reaction product of dimer acid, ethylene diamine, and stearic acid, or (c) mixtures thereof.

4. A phase change ink composition according to claim 1 , wherein the phase change ink carrier comprises an isocyanate-derived material, a urethane isocyanate-derived material, a urea isocyanate-derived material, a urethane/urea isocyanate-derived material, or mixtures thereof.

5. A phase change ink composition according to claim 1 , wherein the phase change ink carrier comprises a mixture of one or more amides and one or more isocyanate-derived materials.

6. A phase change ink composition according to claim 1 , wherein the phase change ink carrier comprises one or more materials selected from paraffins, microcrystalline waxes, polyethylene waxes, ester waxes, amide waxes, fatty acids, fatty alcohols, fatty amides, sulfonamide materials, tall oil rosins, rosin esters, ethylene/vinyl acetate copolymers, ethylene/acrylic acid copolymers, ethylene/vinyl acetate/acrylic acid copolymers, copolymers of acrylic acid with polyamides, ionomers, and mixtures thereof.

7. A phase change ink composition according to claim 1 , wherein the phase change ink carrier is present in the ink in an amount of at least about 0.1 percent by weight of the ink and wherein the phase change ink carrier is present in the ink in an amount of no more than about 99 percent by weight of the ink.

8. A phase change ink composition according to claim 1 , wherein the ink further contains an antioxidant.

9. A phase change ink composition according to claim 8 , wherein the antioxidant is present in the ink in an amount of at least about 0.01 percent by weight of the ink, and wherein the antioxidant is present in the ink in an amount of no more than about 20 percent by weight of the ink.

10. A phase change ink composition according to claim 1 , wherein the ink further contains a viscosity modifier.

11. A phase change ink composition according to claim 10 , wherein the viscosity modifier is present in the ink in an amount of at least about 0.1 percent by weight of the ink and wherein the viscosity modifier is present in the ink in an amount of no more than about 99 percent by weight of the ink.

12. A phase change ink composition according to claim 1 , wherein the colorant is present in the ink in an amount of at least about 0.1 percent by weight of the ink.

13. A phase change ink composition according to claim 1 , wherein the colorant is present in the ink in an amount of no more than about 20 percent by weight of the ink.

14. A phase change ink composition according to claim 1 , wherein the ink has a melting point of no lower than about 50° C. and wherein the ink has a melting point of no higher than about 160° C.

15. A phase change ink composition according to claim 1 , wherein the ink has a melt viscosity at a temperature of about 140° C. of no more than about 30 centipoise.

16. A phase change ink composition according to claim 1 , wherein the ink has a melt viscosity at a temperature of about 140° C. of no less than about 1 centipoise.

17. A phase change ink composition according to claim 1 , wherein a and b are each zero.

18. A phase change ink composition according to claim 1 , wherein A- is an organic dianion of the formula A1-R11-A2 wherein A1 and A2 each, independently of the other, are anions and wherein R11 is (i) an alkylene group, (ii) an arylene group, (iii) an arylalkylene group, or (iv) an alkylarylene group.

19. A phase change ink composition according to claim 1 , wherein at least one of R 1 , R 2 , R 3 , and R 4 is an alkyl group.

20. A phase change ink composition according to claim 19 , wherein the alkyl group is a linear alkyl group.

21. A phase change ink composition according to claim 19 , wherein the alkyl group is a branched alkyl group.

22. A phase change ink composition according to claim 19 , wherein the alkyl group is a saturated alkyl group.

23. A phase change ink composition according to claim 19 , wherein the alkyl group is an unsaturated alkyl group.

24. A phase change ink composition according to claim 19 , wherein the alkyl group is a cyclic alkyl group.

25. A phase change ink composition according to claim 19 , wherein the alkyl group is a substituted alkyl group.

26. A phase change ink composition according to claim 19 , wherein the alkyl group is an unsubstituted alkyl group.

27. A phase change ink composition according to claim 1 , wherein at least one of R 1 , R 2 , R 3 , and R 4 is an aryl group.

28. A phase change ink composition according to claim 27 , wherein the aryl group is a substituted aryl group.

29. A phase change ink composition according to claim 27 , wherein the aryl group is an unsubstituted aryl group.

30. A phase change ink composition according to claim 1 , wherein R 1 and R 2 are joined together to form a ring.

31. A phase change ink composition according to claim 1 , wherein R 1 and R 2 are joined together to form a ring and wherein R 3 and R 4 are joined together to form a ring.

32. A phase change ink composition according to claim 1 , wherein at least one of R 1 , R 2 , R 3 , and R 4 is joined to a phenyl ring in the central structure.

33. A phase change ink composition according to claim 1 , wherein R is an alkyl group.

34. A phase change ink composition according to claim 1 , wherein R is an aryl group.

35. A phase change ink composition according to claim 1 , wherein R is an alkylaryl group.

36. A phase change ink composition according to claim 1 , wherein R is an arylalkyl group.

37. A phase change ink composition according to claim 1 , wherein R has from about 1 to about 100 carbon atoms.

38. A phase change ink composition according to claim 1 , wherein R has from about 18 to about 33 carbon atoms.

39. A phase change ink composition according to claim 1 , wherein R is C 6 H 5 .

40. A phase change ink composition according to claim 1 , wherein R is CH 2 CH 2 .

41. A phase change ink composition according to claim 1 , wherein the colorant is of the formula

wherein n is about 1 to about 1,000 and wherein m is about 1 to about 1,000.

42. A phase change ink composition according to claim 1 , wherein the colorant is of the formula

wherein n is about 1 to about 1,000 and wherein m is about 1 to about 1,000.

43. A process which comprises (1) incorporating into an ink jet printing apparatus a phase change ink composition comprising a phase change ink carrier and a colorant compound of the formula of claim 1

wherein R 1 , R 2 , R 3 , and R 4 each, independently of the others, is (i) a hydrogen atom, (ii) an alkyl group, (iii) an aryl group, (iv) an arylalkyl group, or (v) an alkylaryl group, wherein R˜ and R2 can be joined together to form a ring, wherein R3 and

R4 can be joined together to form a ring, and wherein R˜, R2, R3, and R4 can each be joined to a phenyl ring in the central structure;

wherein a and b each, independently of the others, is an integer which is 0, 1, 2, or 3,

wherein R 5 and R 6 are hydrogen or alkyl;

wherein A is an anion;

wherein CA is either a hydrogen atom or a cation;

wherein R is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, (iv) an alkylaryl group, (v) an alkoxy group, (vi) an acetate group, or (vii) a co-polymer of maleic anhydride;

wherein n is an integer which is about 1 to about 1,000; and

wherein m is an integer which is about 1 to about 1,000;

(2) melting the ink; and (3) causing droplets of the melted ink to be ejected in an imagewise pattern onto a substrate.

44. A process according to claim 43 , wherein the printing apparatus employs a piezoelectric printing process wherein droplets of the ink are caused to be ejected in imagewise pattern by oscillations of piezoelectric vibrating elements.

45. A process according to claim 43 , wherein the substrate is a final recording sheet and droplets of the melted ink are ejected in an imagewise pattern directly onto the final recording sheet.

46. A process according to claim 43 , wherein the substrate is an intermediate transfer member and droplets of the melted ink are ejected in an imagewise pattern onto the intermediate transfer member followed by transfer of the imagewise pattern from the intermediate transfer member to a final recording sheet.

47. A process according to claim 46 , wherein the intermediate transfer member is heated to a temperature above that of the final recording sheet and below that of the melted ink in the printing apparatus.