| 摘要 |
PURPOSE:To obtain an electrophotographic developing agent capable of providing stable charge characteristics without being influenced by environmental conditions such as temp., humidity, of external atmosphere, by incorporating silica gel expressed by the chemical formula: SiO2.nH2O into a resin for constituting a toner. CONSTITUTION:Silica gel expressed by the chemical formula; SiO2.nH2O is incorporated into a resin for constituting a toner. The water content in the silica gel is regulated by an equilibrium vapor pressure of steam under an optional environmental condition. (n) in the formula is different depending on environmental conditions and has a value, as a total water content, in equilibrium with the environmental conditions. Further, the water contained in the silica gel is adsorbed to particles in the inside of the silica gel and is not exposed locally out of the surface of the particles since the physical characteristic of the silica gel is porous and a specific surface area is about 500m<2>/g. Thus, the water is liberated easily. By this constitution, an electrophotographic developing agent having stable charge characteristic without being influenced by environmental conditions such as temp., humidity of external atmosphere, it is obtd. |
