Black magnetic iron oxide particles for magnetic toner and process for producing the same
US6383637B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 2000 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Apr 13, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2998
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Black magnetic iron oxide particles of the present invention having an average particle diameter of 0.1 to 0.3 &mgr;m, comprise:black spinel iron oxide particles as core particles; anda surface coat formed on the surface of each core particle, comprising fine spinel iron oxide particles,the content of FeO in a surface layer having a thickness of from a surface of each black magnetic iron oxide particle to about 3.5% per a radius of each black magnetic iron oxide particle, being 8 to 14% by weight based on the weight of Fe contained in said surface layer.Such black magnetic iron oxide particles not only have a sufficient blackness and excellent electrical properties, flowability and electrification property (charging property), but also exhibit a good compatibility with binder resins such as aromatic vinyl-based resins, acrylic-based resins and copolymer resins thereof, and a good dispersibility in these resins for a magnetic toner.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.