Ferrite carrier for electrophotographic developer and developer using said carrier
US5518849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1994 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Dec 9, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/1075
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention provides a ferrite carrier for an electrophotographic developer characterized in that a core material is ferrite particle composed of 17.0 to 29.0 mol % of Li.sub.2 O and 71.0 to 83.0 mol % of Fe.sub.2 O.sub.3, exhibits a resistance of 2.5.times.10.sup.8 to 2.5.times.10.sup.9 .OMEGA. when a voltage of 250 V is applied, satisfies the relationship: a.sub.1 -a.sub.2 .ltoreq.1.5 when the resistance (R.sub.1) of the ferrite particle exhibited when a voltage of 250 V is applied thereto is taken as a.sub.1 .times.10.sup.b .OMEGA. and the resistance (R.sub.2) thereof exhibited when a voltage of 1000 V is applied thereto is taken as a.sub.2 .times.10.sup.b .OMEGA. (with the proviso that 1.0.ltoreq.a.sub.1 <10, 0.1.ltoreq.a.sub.2, and b is an integer of 6 to 9), and the carrier prepared by coating the ferrite particle with a resin exhibits a resistance of 1.0.times.10.sup.9 to 1.0.times.10.sup.15 .OMEGA. when a voltage 250 V is applied thereto, and has a true specific gravity of 4.70 or below.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.