Magnetic toner, magnetic developer, apparatus unit, image forming apparatus and facsimile apparatus
US5424810A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1992 |
| Grant date | Jun 13, 1995 |
| Priority date | — |
| Expiry date | Sep 10, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/0834
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic toner for electrophotography is composed from a binder resin and a silicon-containing magnetic iron oxide. The magnetic toner has a weigh-average particle size o at most 13.5 .mu.m and has a particle size distribution such that it contains o more than 50 wt, % of magnetic toner particles having a particle size of at least 12.7 .mu.m. The magnetic toner is able to show high developing performances because of richness in fine particles and is also provided with an improved environmental stability because the magnetic iron oxide used therein contains 0.5-4 wt, % silicon (based on total iron content) and has a specific silicon distribution such that the magnetic iron oxide has a total silicon content (A), a silicon content (B) dissolved together with the magnetic iron oxide when the magnetic iron oxide is dissolved up to 20 wt, % dissolution of iron, and a superficial silicon content (C), satisfying relations of B/A=44-84% and C/A=10-55%. The performances are enhanced if the magnetic toner is blended with additives such as inorganic fine powder or resin fine particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.