Two phase ferroelectric-ferromagnetic composite carrier
US5190842A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1991 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Dec 19, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/11
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is an interdispersed two-phase ferrite composite which comprises, as a ferromagnetic phase, a magnetically hard ferrite material having a hexagonal crystalline structure of the general formula MO.6Fe.sub.2 O.sub.3 in which M is selected from the group consisting of strontium, barium, lead and mixtures thereof exhibiting 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, as a ferroelectric phase, a ferroelectric material comprised of at least one of the double oxides of titanium, zirconium, tin, hafnium or germanium and either an alkaline earth or lead or cadmium, in which the mole ratio of the ferromagnetic phase to the ferroelectric phase is from about 1:1 to about 1:4. Also disclosed are carrier particles formed from magnetized particles of the composite which optionally can be polymerically coated, an electrostatic two-component dry developer composition comprising electrically insulative charged toner particles mixed with oppositely charged carrier particles formed from magnetized, and optionally polymerically coated, particles of the composite su…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.