METHOD AND APPARATUS FOR LIQUID ELECTROSTATIC PRINTING

• US 20090226839A1
• Filed: 07/27/2005
• Published: 09/10/2009
• Est. Priority Date: 07/27/2005
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Katz, Gregory, Iraqi, Muhammad, Teishev, Albert
• Granted Patent: US 8,158,321 B2
• Time in Patent Office: Days
• US Class Current: 430/115
• CPC Class Codes: G03G 2215/0629 liquid at room temperature
• CPC Class Codes: G03G 2215/0658 Liquid developer devices
• CPC Class Codes: G03G 9/125 characterised by the liquid
• CPC Class Codes: G03G 9/13 characterised by polymer components
• CPC Class Codes: G03G 9/131 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: G03G 9/132 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: G03G 9/133 Graft-or block polymers
• CPC Class Codes: G03G 9/135 characterised by stabiliser or charge-controlling agents
• CPC Class Codes: G03G 9/1355 Ionic, organic compounds

Abstract

Novel UV-curable liquid toner compositions, methods for preparing same and imaging processes and apparatus utilizing same are provided. The UV-curable liquid toner compositions include a dispersion of toner particles in a hydrocarbon based liquid carrier and one or more UV-curable component(s) which form a part of the carrier.

Claims

1. A UV-curable liquid toner composition for use in liquid electrostatic printing comprising:

a dispersion of toner particles suspended in a hydrocarbon-based liquid carrier; and

at least one UV-curable component;

wherein;

a concentration of the toner particles is about 2 percent by weight of a total weight of the composition;

a concentration of the at least one UV-curable component ranges from about 0.5 to about 5 percent by weight of the total weight of the composition; and

a concentration of the hydrocarbon-based liquid carrier ranges from 90 to 97.5 percent by weight of the total weight of the composition.

2. A process of preparing the UV-curable liquid toner composition of claim 1, the process comprising:

providing said at least one UV-curable component;

providing said dispersion of toner particles suspended in said hydrocarbon-based liquid carrier; and

dissolving said at least one UV-curable component in said hydrocarbon-based liquid carrier, thereby providing the UV-curable liquid toner composition.

3. A method of forming an image on a substrate, the method comprising:

providing the UV-curable liquid toner composition of claim 1;

forming an electrostatic image on an imaging surface;

developing said electrostatic image using said UV curable liquid toner composition, to thereby form a toner image containing said UV-curable composition;

transferring said toner image to the substrate; and

UV-irradiating the substrate, to thereby cure the image on the substrate.

4. The method of claim 3, wherein said forming said electrostatic image on said imaging surface comprises uniformly charging said imaging surface.

5. The method of claim 4, wherein said forming said electrostatic image on said imaging surface further comprises emitting light constituting an image on said imaging surface, so as to selectively discharge predetermined regions on said imaging surface.

6. The method of claim 3, wherein said developing said electrostatic image comprises charging said UV curable liquid toner composition and applying said UV curable liquid toner composition onto said imaging surface.

7. The method of claim 3, wherein said application of said UV curable liquid toner composition onto said imaging surface is by a sprayer.

8. The method of claim 3, wherein said application of said UV curable liquid toner composition onto said imaging surface is by a developing roller.

9. The method of claim 3, further comprising transferring said toner image to an intermediate transfer member, prior to said transfer of said toner image to the substrate.

10. The method of claim 3, further comprising squeezing said toner image prior to said transfer of said toner image to the substrate.

11. A liquid electrostatic printing apparatus, comprising:

an imaging assembly being capable of forming and transferring an image to a substrate, said imaging assembly having a chamber containing the UV-curable liquid toner composition of claim 1; and

at least one UV irradiation source for curing said image onto said substrate.

12. The apparatus of claim 11, wherein said imaging assembly comprises a movable imaging surface capable of carrying a latent image thereon, an exposing unit capable of emitting light on said imaging surface so as to form said latent image thereon;

and a developing unit being in fluid communication with said chamber, for applying said UV-curable liquid toner composition onto said imaging surface, thereby to provide a developed image.

13. The apparatus of claim 12, wherein said imaging surface is embodied on a rotating drum.

14. The apparatus of claim 12, wherein said imaging assembly further comprises a charging unit, for uniformly charging said imaging surface.

15. The apparatus of claim 12, wherein said developing unit is comprises at least one electrode operable to apply said UV-curable liquid toner composition on said imaging.

16. The apparatus of claim 12, wherein said imaging assembly further comprises a squeegee being in contact with said imaging surface, for squeezing said UV-curable liquid toner composition on said imaging surface.

17. The apparatus of claim 12, wherein said imaging assembly further comprises an intermediate transfer member, oppositely moving relative to said imaging surface and configured to receive said developed image from said imaging surface, and to transfer said developed image to a substrate.

18. The apparatus of claim 12, wherein said developing unit is designed and constructed to apply different colors of said UV-curable liquid toner composition on said imaging surface.

19. The apparatus of claim 18, wherein said developing unit comprises a development roller being spaced apart from said imaging surface, thereby forming a gap between said development roller and said imaging surface.

20. The apparatus of claim 18, wherein said developing unit further comprises a multicolor liquid toner sprayer, designed and constructed to spray said UV-curable liquid toner composition onto a portion of said development roller, a portion of said imaging surface and/or a development region formed between said imaging surface and said development roller.

21. The apparatus of claim 12, wherein said developing unit comprises a development roller, a main electrode and a back electrode, said main electrode and a back electrode said having a gap therebetween and configured such that said UV-curable liquid toner composition is forced through said gap to at least partially plate said development roller.

22. The UV-curable composition of claim 1, wherein said UV-curable component forms a part of said liquid carrier.

23. The UV-curable composition of claim 1, wherein a concentration of said at least one UV-curable component ranges from about 1 weight percentages to about 3 weight percentages of the total weight of the composition.

24. The UV-curable composition of claim 1, wherein said UV-curable component comprises at least one UV-polymerizable compound.

25. The UV-curable composition of claim 24, wherein said at least one UV-polymerizable compound comprises at least one acrylate.

26. The UV-curable composition of claim 25, wherein said at least one acrylate is selected from the group consisting of a monoacrylate, a diacrylate and a mixture thereof.

27. The UV-curable composition of claim 26, wherein said monoacrylate is selected from the group consisting of isodecyl acrylate and isobornyl acrylate.

28. The UV-curable composition of claim 26, wherein said diacrylate is dipropylene glycol diacrylate.

29. The UV-curable composition of claim 1, wherein a concentration of said UV-polymerizable compound ranges from about 75 weight percentages to about 95 weight percentages of the total weight of said UV-curable component.

30. The UV-curable composition of claim 1, wherein said UV-curable component further comprises at least one photoinitiator.

31. The UV-curable composition of claim 1, wherein said UV-curable component further comprises at least one stabilizer.

32. The UV-curable composition of claim 1, wherein said at least one UV-curable component comprises:

about 75-95 weight percentages of at least one UV-polymerizable compound selected from the group consisting of a monoacrylate and a diacrylate;

about 5-10 weight percentages of at least one photoinitiator; and

about 0.1-0.5 weight percentages of at least one stabilizer.

33. The process of claim 2, wherein providing said at least one UV-curable component comprises:

dissolving said at least one photoinitiator and said at least one stabilizer in said at least one UV-polymerizable compound.