Claims
- 1. A carrier, for an electrostatographic developer, comprising particles of a hard magnetic ferrite material as the core and having a coating of a polymer resin, said resin in turn having a coating of an organic conductive material.
- 2. The carrier according to claim 1 wherein said organic conductive material is a conductive charge control agent.
- 3. The carrier according to claim 2 wherein said conductive charge control agent is is a quaternary ammonium salt of the formula:
5
- 4. The carrier according to claim 2 wherein said conductive charge control agent is a quaternary ammonium salt of the formula:
6
- 5. The carrier according to claim 2 wherein said conductive charge control agent is an alkyl pyridinium compound or its hydrate of the formula:
7
- 6. The carrier of claim 2 wherein the charge agent is selected from the group consisting of lauramidopropyl trimethylammonium methylsulfate, cetyl pyridinium chloride and dioctadecyl dimethyl ammonium chloride.
- 7. The carrier according to claim 1 wherein the amount of organic conductive material ranges from about 50 to 500 ppm by weight of the combined hard magnetic ferrite material and polymer resin coating.
- 8. The carrier according to claim 4 wherein the amount of charge control agent is between 200 ppm and 350 ppm by weight of organic conductive material.
- 9. The carrier of claim 1 wherein the hard magnetic ferrite material has crystalline structure that exhibits a coercivity of at least 300 Oersteds when magnetically saturated and an induced magnetic moment of at least 20 EMU/g when in an applied magnetic field of 1000 Oersteds and having a number average particle diameter of from 10.0 to 38.0 micrometers.
- 10. The carrier of claim 1 wherein said polymer resin coating is poly(vinylidinefluoride), poly(methylmethacrylate) or mixtures of these two polymers.
- 11. An electrostatographic two-component dry developer composition for use in the development of electrostatic latent images which comprises a mixture of charged toner particles and oppositely charged carrier particles according to claim 1.
- 12. The electrostatographic developer of claim 11 comprising from about 75 to about 99 weight percent of the carrier and from about 1 to about 25 weight per cent of the toner.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application of Ser. No. 08/649,384 filed May 17, 1996, entitled “Hard Carrier Particles Coated With a Polymer Resin and a Conductive Material”.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
08649384 |
May 1996 |
US |
Child |
09096985 |
Jun 1998 |
US |