Conductive developer compositions and processes thereof

Abstract

A developer composition with a conductivity of from about 10 -6 to about 10 -12 (ohm-cm) -1 over a toner concentration of from about 1 to about 6 weight percent, which developer is comprised of a toner containing resin particles, pigment particles and a metal salt of a fatty acid; and carrier particles with rough surfaces thereon.

What is claimed is: 
     
       1. A developer composition with a conductivity of from about 10 -6  to about 10 -12  (ohm-cm) -1  over a toner concentration of from about 1 to about 6 weight percent, which developer is comprised of a toner containing resin particles, pigment particles and a metal salt of a fatty acid; and carrier particles with rough surfaces thereon. 
     
     
       2. A developer composition in accordance with claim 1 wherein the conductivity is from about 10 -9  to about 10 -10  (ohm-cm) -1 . 
     
     
       3. A developer composition in accordance with claim 1 wherein the conductivity is from about 6×10 -10  to about 3×10 -10  (ohm-cm) -1 . 
     
     
       4. A developer composition in accordance with claim 1 wherein the carrier particles are comprised of a ferrite. 
     
     
       5. A developer composition in accordance with claim 4 wherein the carrier particles are comprised of a copper zinc ferrite. 
     
     
       6. A developer composition in accordance with claim 1 wherein the carrier particles are comprised of steel. 
     
     
       7. A developer composition in accordance with claim 1 wherein the metal salt is present in an amount of from about 0.1 to about 1 percent by weight. 
     
     
       8. A developer composition in accordance with claim 1 wherein the metal salt is zinc stearate. 
     
     
       9. A developer composition in accordance with claim 1 wherein the salt is present as an external additive. 
     
     
       10. A developer composition in accordance with claim 1 containing colloidal silica additive particles. 
     
     
       11. A developer composition in accordance with claim 10 wherein the particles are present in an amount of from about 0.1 to about 1 percent by weight. 
     
     
       12. A developer composition in accordance with claim 1 containing a charge enhancing additive. 
     
     
       13. A developer composition in accordance with claim 12 wherein the charge enhancing additive is selected from the group consisting of alkyl pyridinium halides, and distearyl dimethyl ammomium methyl sulfate. 
     
     
       14. A developer composition in accordance with claim 12 wherein the charge enhancing additive is present in an amount of from about 0. 1 to about 5 weight percent. 
     
     
       15. A developer composition in accordance with claim 1 wherein the resin particles are selected from the group consisting of styrene acrylates, styrene methacrylates, polyesters, and styrene butadienes. 
     
     
       16. A developer composition in accordance with claim 1 wherein the pigment particles are selected from the group consisting of carbon black, cyan, magenta, yellow, red, blue, green, brown, and mixtures thereof. 
     
     
       17. A developer composition in accordance with claim 1 wherein the carrier particles contain a polymeric coating. 
     
     
       18. A developer composition with a conductivity of from about 10 -10  to about 10 -12  (ohm-cm) -1  over a toner concentration of from about 1 to about 6 weight percent, which developer is comprised of a toner composition, and a metal salt of a fatty acid; and a carrier with rough surfaces thereon. 
     
     
       19. A developer composition in accordance with claim 18 wherein the salt is present as an external additive. 
     
     
       20. A developer composition in accordance with claim 18 wherein the carrier is a ferrite or steel. 
     
     
       21. A developer composition in accordance with claim 18 wherein the carrier contains thereover a polymeric coating. 
     
     
       22. A developer composition in accordance with claim 21 wherein the polymeric coating is comprised of a fluoropolymer, polymethylmethacrylate, or a terpolymer of styrene, methylmethacrylate, and an organosilane. 
     
     
       23. A developer composition in accordance with claim 21 wherein the polymeric coating contains conductive particles therein. 
     
     
       24. A developer composition in accordance with claim 18 wherein the toner is comprised of resin and pigment. 
     
     
       25. A developer composition in accordance with claim 24 wherein the resin is a styrene acrylate, a styrene methacrylate, a styrene butadiene, a polyester, or mixtures thereof. 
     
     
       26. A developer composition in accordance with claim 24 wherein the pigment is carbon black, magnetite, cyan, magneta, yellow, red, blue, green, or brown. 
     
     
       27. A developer composition in accordance with claim 18 wherein the toner contains charge enhancing additives. 
     
     
       28. A process for the preparation of stable developer compositions with a conductivity of from about 10 -10  to about 10 -12  (ohm-cm) -1  over a toner concentration of from about 1 to about 6 weight percent, which comprises admixing a toner composition comprised of resin particles, pigment particles, optional charge enhancing additives, containing on the surface thereof colloidal silicas, metal salts, metal salts of fatty acids, or mixtures thereof, with carrier particles with rough surfaces thereon. 
     
     
       29. A process for the preparation of stable developer compositions with a conductivity of from about 10 -10  to about 10 -12  (ohm-cm) -1  over a toner concentration of from about 1 to about 6 weight percent, which comprises admixing a toner composition comprised of resin particles, pigment particles, optional charge enhancing additives, and on the surface thereof colloidal silicas, metal salts, metal salts of fatty acids, or mixtures thereof, with ferrite carrier particles containing rough surfaces thereon. 
     
     
       30. A process in accordance with claim 28 wherein the conductivity sensitivity is about 0.1. 
     
     
       31. A process in accordance with claim 28 wherein the rough carrier surfaces are obtained by the disintegration of fired carrier particles. 
     
     
       32. A process in accordance with claim 28 wherein there is added to the carrier a polymeric coating. 
     
     
       33. A process in accordance with claim 28 wherein the resin particles for the toner are selected from the group consisting of polyesters, styrene butadiene copolymers, styrene acrylate copolymers, and styrene methacrylate copolymers. 
     
     
       34. A process in accordance with claim 28 wherein the resin for the toner is a polyester results from the condensation reaction of dimethylterephthalate, 1,2-propanediol, 1,3-butanediol, and pentaerythritol; or wherein the polyester results from the condensation reaction of dimethylterephthalate, 1,2-propanediol, diethylene glycol, and pentaerythritol. 
     
     
       35. A developer in accordance with claim 18 wherein there is selected as the toner a styrene methylacrylate copolymer grafted with or containing a low molecular wax of polypropylene or polyethylene, and a second resin comprised of a styrene acrylate acrylonitrile terpolymer. 
     
     
       36. A developer in accordance with claim 18 wherein the toner is comprised of first resin particles, and second resin particles. 
     
     
       37. A developer in accordance with claim 1 wherein the carrier particles contain a partial or conductive coating thereover. 
     
     
       38. A developer composition with a conductivity of from about 10 -6  to about 10 -12  (ohm-cm) -1 , which developer is comprised of a toner containing resin particles, pigment particles and a metal salt of a fatty acid; and carrier particles with rough surfaces thereon. 
     
     
       39. A developer composition with a conductivity of from about 10 -10  to about 10 -12  (ohm-cm) -1 , which developer is comprised of a toner composition, and a metal salt of a fatty acid; and a carrier with rough surfaces thereon. 
     
     
       40. A process in accordance with claim 28 wherein the carrier particles with rough surfaces thereon are prepared by crushing or disintegrating carrier core materials. 
     
     
       41. A process in accordance with claim 28 wherein the rough surface carrier cores are prepared by crushing cores in the presence of hydrogen gas at a temperature of from about 300° to about 500° C.