| 摘要 |
Conductive hard magnetic carrier particles are disclosed which are useful for development of electrostatic latent images. The carrier particles comprise a core of a hard magnetic material, preferably a hard magnetic ferrite such as strontium ferrite, which has a metal oxide composition disposed on the outer surface of the core. The metal oxide composition comprises a layer of an oxide of at least one metal, and in some embodiments, the metal oxide composition may be represented by the formula MOn/2 where M is at least one multi-valent metal represented by Mn+ where n is an integer of at least 4. Also disclosed are carrier particles having the foregoing structure wherein the outer surface of the core further defines a transition zone which extends into the core of hard magnetic ferrite, wherein the ferrite crystal structure within the transition zone is doped with multi-valent metal ions of the formula Mn+, where n is an integer of at least 4. The carrier particles may be used in making single- and two-component developers for use development of electrostatic latent image patterns in an electrographic process. Also disclosed are methods for using such carrier particles in an electrographic process such that the speed and imaging of the process is improved.
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