| 摘要 |
PURPOSE:To extend a life of a ferrite carrier for electrostatic development by forming a film of conductive tin oxide on the surface of the ferrite and then a film of a specified thickness made of a tough fluororesin or epoxy resin high in electrical resistance and humidity resistance on the surface of a spinel type ferrite carrier of a specified particle diameter. CONSTITUTION:An electrostatic developing ferrite carrier is obtained by forming a tin oxide film on the surface of a spinel type ferrite and then a 0.01-30mum thick film made of a fluororesin or epoxy resin having high electrical resistance and humidity resistance on the surface of a ferrite carrier of 10-1,000mum particle diameter. Triboelectrification of the magnetic carrier can be controlled by forming a single layer of the fluororesin alone or double layer films of the thin fluororesin stuck first and further the epoxy resin to optionally change electrical properties. Said film forms a tough film on the surface of the spinel type ferrite carrier and stripping of the film from the carrier during development and subsequent staining due to adhesion of the toner to the resin occur scarcely, and therefore, the obtained magnetic carrier is extended in life. |
