Electrophotographic magnetic dry developer containing cerium oxide and hydrophobic silica
US4824752A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1988 |
| Grant date | Apr 25, 1989 |
| Priority date | — |
| Expiry date | Sep 12, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/104
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic dry developer, comprising negatively chargeable insulating magnetic toner particles containing, at least, a binder resin, a magnetic substance, and an organo-chromium or -zinc complex; cerium oxide particles containing CeO.sub.2 as a predominant component and having a volume average particle size of 1.0 to 4.0 microns, a heating loss of 0.5 wt. % or less on heating up to 100.degree. C. and a BET specific surface area of 15 m.sup.2 /g or less as measured by the nitrogen adsorption method; and hydrophobicity-imparted negatively chargeable silicon oxide particulates. The cerium oxide particles have a function of disintegrating particularly the hydrophobicity-imparted silicon oxide particulates and enhance the attachment thereof to the toner particles, whereby the developing characteristics including the magnetic triboelectric chargeability are stabilized from the initial stage of electrophotographic copying operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.