Magnetic toner for electrophotography
US4137188A · kind A · utility
Inventors
Key dates
| Filing date | Feb 1, 1978 |
| Grant date | Jan 30, 1979 |
| Priority date | — |
| Expiry date | Feb 1, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/104
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An insulating magnetic toner useful as a one component developer for electro-photography consisting essentially of a ferro-magnetic material, a resin and a charge controlling agent. The preferred toner mixture has an average particle size in the range from about 7 to about 30 .mu.m and is substantially free of particles having a size smaller than 1 .mu.m. The toner is preferably prepared by mixing a ferromagnetic material, a resin and a charge controlling agent, heat kneading, cooling and then granulating the mixture to form fine particles, contacting the pacticles with a hot gas of a temperature higher than the toner softening point and lower than 500.degree. C to fuse particles smaller than about 1 .mu.m to larger particles, cooling and selecting the particles of an average particle size of about 7 to about 30 .mu.m.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.