| 摘要 |
Electrographic carrier particles with improved conductivity and stability are prepared from magnetic stainless steel particles of at least 9 weight percent chromium content. The particles are passivated by reaction with nitric acid. This forms a chromium-rich, stable film on the particle surfaces. Before passivation the particles may also be treated, e.g., with hydrofluoric acid, to remove surface silicon. The passivated particles, preferably after thinly coating with a resin, e.g., poly(vinylidene fluoride), are mixed with toner powder for electrographic dry development. |
