Claims
- 1. A development system for magnetic toner comprising:
a supply of dry developer mixture comprising magnetic toner particles and hard magnetic carrier particles; a non-magnetic, cylindrical shell for transporting the developer from said supply to a development zone, wherein said shell is rotatable or stationary; a rotating magnetic core of a pre-selected magnetic field strength; means for rotating at least said magnetic core to provide for the transport of said toner particles from said shell to an electrostatic image.
- 2. The development system of claim 1, wherein said magnetic toner particles have a spacing agent on the surface of said magnetic toner particles.
- 3. The development system of claim 2, wherein said spacing agent comprises silica.
- 4. The development system of claim 2, wherein said spacing agent comprises at least one metal oxide.
- 5. The development system of claim 2, wherein said spacing agent comprises at least one inorganic oxide.
- 6. The development system of claim 2, wherein said spacing agent comprises at least one polymeric material.
- 7. The development system of claim 2, wherein said spacing agent comprises acrylic polymer, silicone-based polymer, styrenic polymer, fluoropolymer, or mixtures thereof.
- 8. The development system of claim 2, wherein said spacing agent is present in an amount of from about 0.05 to about 1.5 wt %, based on the weight of the toner.
- 9. The development system of claim 2, wherein said spacing agent is present in an amount of from about 0.1 to about 1.0 wt %, based on the weight of the toner.
- 10. The development system of claim 2, wherein said spacing agent is present in an amount of from about 0.2 to about 0.6 wt %, based on the weight of the toner.
- 11. The development system of claim 1, wherein said rotating magnetic core operates at a speed of at least about 100 rpm.
- 12. The development system of claim 1, wherein said rotating magnetic core operates at a speed of at least about 500 rpm.
- 13. The development system of claim 1, wherein said rotating magnetic core operates at a speed of at least about 1,000 rpm.
- 14. The development system of claim 1, wherein said rotating magnetic core operates at a speed of at least about 2,000 rpm.
- 15. The development system of claim 1, wherein said rotating magnetic core operates at a speed of from about 500 to about 2,500 rpm.
- 16. The development system of claim 1, wherein said development zone has a transfer potential such that the electrostatic forces associated with a charge image are sufficient to strip said magnetic toner particles away from said carrier particles.
- 17. The development system of claim 16, wherein said transfer potential is at least about 800 volts.
- 18. The development system of claim 16, wherein said transfer potential is from about 1,000 volts to about 2,500 volts.
- 19. A method for developing an electrostatic image with a magnetic toner comprising developing an electrostatic image member bearing an electrostatic image pattern by moving the image member through a development zone and transporting developer through the development zone in developing relation with the charge pattern of the moving imaging member by rotating an alternating-pole magnetic core of a pre-selected magnetic field strength within an outer non-magnetic shell, which is rotating or stationary, and controlling the directions and speeds of the core and optionally the shell rotations so that developer flows through the development zone in a direction co-current with the image member movement, wherein said developer comprises charged magnetic toner particles and oppositely charged hard magnetic carrier particles.
- 20. The method of claim 19, wherein said method has a developer flow, and said moving imaging member and said developer flow are moving at substantially the same speed.
- 21. The method of claim 19, wherein said carrier particles comprise hard magnetic material exhibiting a coercivity of at least about 300 gauss when magnetically saturated and also exhibit an induced magnetic moment of at least about 20 EMU/gm when in an externally applied field of 1,000 gauss.
- 22. The method of claim 19, wherein said magnetic toner particles comprise a spacing agent on the surface of said magnetic toner particles.
- 23. The method of claim 22, wherein said spacing agent comprises silica.
- 24. The method of claim 22, wherein said spacing agent comprises at least one metal oxides.
- 25. The method of claim 22, wherein said spacing agent comprises at least one inorganic oxide.
- 26. The method of claim 22, wherein said spacing agent comprises at least one polymeric material.
- 27. The method of claim 22, wherein said spacing agent comprises acrylic polymer, silicone-based polymer, styrenic polymer, fluoropolymer, or mixtures thereof.
- 28. The method of claim 22, wherein said spacing agent is present in an amount of from about 0.05 to about 1.5 wt %, based on the weight of the toner.
- 29. The method of claim 22, wherein said spacing agent is present in an amount of from about 0.1 to about 1.0 wt %, based on the weight of the toner.
- 30. The method of claim 22, wherein said spacing agent is present in an amount of from about 0.2 to about 0.6 wt %, based on the weight of the toner.
- 31. A developer comprising carrier particles and toner, wherein the toner is present in an amount of from about 8 wt % to about 45 wt %, based on the total weight of the developer.
- 32. The developer of claim 31, wherein said toner is present in an amount of from about 15 wt % to about 25 wt %, based on the total weight of the developer.
- 33. The developer of claim 31, wherein said toner is present in an amount of from about 17 wt % to about 20 wt %, based on the total weight of the developer.
- 34. The developer of claim 31, wherein said carrier particles are hard magnetic carrier particles.
- 35. The developer of claim 31, wherein said toner comprises magnetic toner particles.
- 36. The developer of claim 31, wherein said toner particles have a spacing agent on the surface of said toner particles.
- 37. The developer of claim 31, wherein said toner comprises magnetic toner particles and said carrier particles are hard magnetic carrier particles
- 38. The developer of claim 37, wherein said magnetic toner particles have a spacing agent on the surface of said magnetic toner particles.
- 39. The developer of claim 38, wherein said spacing agent comprises silica.
- 40. The developer of claim 38, wherein said spacing agent comprises at least one metal oxide.
- 41. The developer of claim 38, wherein said spacing agent comprises at least one inorganic oxide.
- 42. The developer of claim 38, wherein said spacing agent comprises at least one polymeric material.
- 43. The developer of claim 38, wherein said spacing agent comprises acrylic polymer, silicone-based polymer, styrenic polymer, fluoropolymer, or mixtures thereof.
- 44. The developer of claim 38, wherein said spacing agent is present in an amount of from about 0.05 to about 1.5 wt %, based on the weight of the toner.
- 45. The developer of claim 38, wherein said spacing agent is present in an amount of from about 0.1 to about 1.0 wt %, based on the weight of the toner.
- 46. The developer of claim 38, wherein said spacing agent is present in an amount of from about 0.2 to about 0.6 wt %, based on the weight of the toner.
- 47. A MICR developer comprising magnetic toner particles having a magnetic loading of less than 28% by weight, based on the weight of the toner and hard magnetic carrier particles.
- 48. The developer of claim 47, wherein said magnetic loading is less than 24% by weight.
- 49. The developer of claim 47, wherein said magnetic loading is from about 10% to about 24% by weight.
- 50. The developer of claim 47, wherein said magnetic loading is from about 16% to about 22% by weight.
- 51. A MICR developer comprising hard magnetic carrier particles and magnetic toner particles comprising at least one magnetic additive, at least one resin, at least one charge agent, and optionally, at least one colorant, wherein said magnetic toner particles have a spacing agent located on the surface of said magnetic toner particles.
- 52. The MICR developer of claim 51, wherein said spacing agent comprises silica.
- 53. The MICR developer of claim 51, wherein said spacing agent comprises at least one metal oxide.
- 54. The MICR developer of claim 51, wherein said spacing agent comprises at least one inorganic oxide.
- 55. The MICR developer of claim 51, wherein said spacing agent comprises at least one polymeric material.
- 56. The MICR developer of claim 51, wherein said spacing agent comprises acrylic polymer, silicone-based polymer, styrenic polymer, fluoropolymer, or mixtures thereof.
- 57. The MICR developer of claim 51, wherein said spacing agent is present in an amount of from about 0.05 to about 1.5 wt %, based on the weight of the toner.
- 58. The MICR developer of claim 51, wherein said spacing agent is present in an amount of from about 0.1 to about 1.0 wt %, based on the weight of the toner.
- 59. The MICR developer of claim 51, wherein said spacing agent is present in an amount of from about 0.2 to about 0.6 wt %, based on the weight of the toner.
- 60. The MICR developer of claim 51, further comprising at least one wax.
- 61. The MICR developer of claim 60, wherein said wax comprises polyolefin wax.
- 62. The development system of claim 1, wherein a AC bias is present in superposition with a DC bias of the development system.
- 63. The development system of claim 62, wherein said AC bias has a waveform having a frequency of from about 300 Hz to about 3000 Hz and a peak-to-peak amplitude of from about 0.2 kV to about 5 kV.
Parent Case Info
[0001] This application is a divisional of U.S. patent application Ser. No. 09/747,764, filed Dec. 26, 2000, which is incorporated herein in its entirety by reference.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09747764 |
Dec 2000 |
US |
Child |
10403539 |
Mar 2003 |
US |