Production of ferrite electrostatographic carrier materials having improved properties
US4075391A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1975 |
| Grant date | Feb 21, 1978 |
| Priority date | — |
| Expiry date | Oct 29, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for preparing humidity-insensitive electrostatographic ferrite carrier materials comprising dry-blending ferrite-forming metal oxides, calcining the blended oxides to provide them with a saturation magnetic moment of about 6 to 30 electromagnetic units per gram, milling the calcined oxides in a slurry to reduce their particle size to about 0.8 to 1.6 microns while adding manganese oxide, copper oxide, and a sodium-free deflocculant to the slurry, pumping the milled slurry to holding/feeding tanks and adding a binder material to the slurry, spray-drying the slurry to form substantially spherical beads, screening the spray-dried beads, firing the screened beads in an ambient atmosphere at a temperature of up to about 2500.degree. F. for up to about 8 hours, deagglomerating the fired beads, and screening the beads to obtain ferrite carrier particles having controlled surface species and physical properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.