Fluorescent liquid toner and method of printing using same

1. Charged toner particles for use in electrostatic imaging, comprising:

a toner polymer; and

at least one particulate fluorescent material,

wherein the toner particles are formed with fibrous extensions.

2. A liquid toner, comprising:

a carrier liquid; and

charged toner particles dispersed in the carrier liquid, said charged particles comprising:

a toner polymer; and

at least one particulate fluorescent material,

wherein the toner particles are formed with fibrous extensions.

3. A liquid toner according to claim 2 wherein the carrier liquid is substantially non-conducting.

4. A liquid toner according to claim 2 , including a charge director for aiding in the charging of the toner particles.

5. A printing method, comprising:

providing an electrostatic image;

developing the image with a toner according to claim 2 .

6. A method according to claim 5 and including:

transferring the developed image to a final substrate.

7. A method according to claim 6 wherein transferring the developed image to a final substrate comprises:

transferring the developed image to an intermediate transfer member; and

subsequently transferring the developed image to the final substrate.

8. A liquid toner according to claim 2 wherein the charged toner particles comprise a pigment additional to the at least one particulate fluorescent material.

9. A liquid toner according to claim 8 wherein the additional pigment is fluorescent.

10. A liquid toner according to claim 8 wherein the additional pigment is not fluorescent.

11. A liquid toner according to claim 8 wherein the fluorescent color of the at least one particulate fluorescent material is different from that of the additional pigment.

12. A liquid toner according to claim 8 wherein the at least one particulate fluorescent material and the additional pigment is greater than about 30% by weight of the total dry solids of the toner particle.

13. A liquid toner according to claim 8 wherein the at least one particulate fluorescent material and the additional pigment is greater than about 40% by weight of the total dry solids of the toner particle.

14. A liquid toner according to claim 2 wherein the particulate fluorescent material comprises an encapsulated dye material.

15. A liquid toner according to claim 14 wherein the dye material is encapsulated in an encapsulating polymer.

16. A liquid toner according to claim 15 wherein the encapsulating polymer is a thermoplastic polymer.

17. A liquid toner according to claim 15 wherein the encapsulating polymer is a thermosetting polymer.

18. A liquid toner according to claim 2 wherein the particulate fluorescent particulate material is in the form of pigment particles having a size greater than about 2 micrometers.

19. A liquid toner according to claim 2 wherein the particulate fluorescent particulate material is in the form of pigment particles having a size greater than about 3 micrometers.

20. A liquid toner according to claim 2 wherein the particulate fluorescent particulate material is in the form of pigment particles having a size of 4 micrometers or more.

21. A liquid toner according to claim 2 wherein the toner particle size is greater than about 3 micrometer.

22. A liquid toner according to claim 2 wherein the toner particle size is greater than about 5 micrometers.

23. A liquid toner according to claim 2 wherein the toner particle size is smaller than about 10 micrometers.

24. A liquid toner according to claim 2 wherein the toner particle size is smaller than about 9 micrometers.

25. A liquid toner according to claim 2 wherein the particulate fluorescent material comprises more than 40% of the non-volatile solids portion of the particle.

26. A liquid toner according to claim 25 wherein the particulate fluorescent material comprises more than 50% of the non-volatile solids portion of the particle.

27. A liquid toner according to claim 2 wherein the toner polymer comprises an ethylene methacrylic acid copolymer.

28. A method of producing a liquid toner comprising:

mixing a toner polymer, a carrier liquid and particulate fluorescent material; and

grinding the mixture until toner particles are produced, including choosing the conditions of grinding and the toner polymer such that the toner particles are formed with fiberous extensions.

29. A method according to claim 28 wherein mixing comprises mixing a pigment additional to the at least one particulate fluorescent material with the other materials.

30. A method according to claim 29 wherein the additional pigment is fluorescent.

31. A method according to claim 29 wherein the additional pigment is not fluorescent.

32. A method according to claim 29 wherein the fluorescent color of the at least one particulate fluorescent material is different from that of the additional pigment.

33. A method according to claim 29 wherein the at least one particulate fluorescent material and the additional pigment is greater than about 30% by weight of the total dry solids of the mixture.

34. A method according to claim 33 wherein the at least one particulate fluorescent material and the additional pigment is greater than about 45% by weight of the total dry solids of the toner particle.

35. A method according to claim 28 wherein the particulate fluorescent material comprises an encapsulated dye material.

36. A method according to claim 35 wherein the dye material is encapsulated in an encapsulating polymer.

37. A method according to claim 36 wherein the encapsulating polymer is a thermoplastic polymer.

38. A method according to claim 36 wherein the encapsulating polymer is a thermosetting polymer.

39. A method according to claim 28 wherein the particulate fluorescent particulate material is in the form of pigment particles having a size greater than about 2 micrometers.

40. A method according to claim 28 wherein the grinding is continued until the toner particle size is smaller than about 10 micrometers.

41. A method according to claim 28 wherein the grinding is interrupted while the particle size is greater than about 3 micrometers.

42. A method according to claim 28 wherein the grinding is interrupted while the particle size is greater than about 5 micrometers.

43. A method according to claim 28 wherein the particulate fluorescent particulate material is in the form of pigment particles having a size greater than about 3 micrometers.

44. A method according to claim 28 wherein the toner particle size is smaller than about 5 micrometer.

45. A method according to claim 28 wherein the particulate fluorescent material comprises more than 40% of the non-volatile solids portion of the mixture.

46. A method according to claim 45 wherein the particulate fluorescent material comprises more than 50% of the non-volatile solids portion of the mixture.

47. A method according to claim 28 wherein the toner polymer comprises an ethylene methacrylic acid copolymer.

48. A method according to claim 28 wherein mixing comprises:

first plasticizing the toner polymer with the carrier liquid; and

subsequently adding additional carrier liquid and particulate fluorescent material.