| 摘要 |
PURPOSE:To reduce the environmental fluctuations of a triboelectrifying quantity by combining toner having the external addition of silica showing specific triboelectrified properties and a resin covering carrier incorporating quaternary ammonium salt. CONSTITUTION:This negatively electrified electrostatic charge developing two component developer has the toner having the externally added additive of silica powder processed with a silane coupling agent having the triboelectrifying properties of both the positive and the negative, and a carrier covered by insulating resin incorporating the quaternary ammonium salt having negative iron except halogen. As the silica showing excellent electrifying properties, one that the triboelectrifying quantity under low humidity (for instance, it is left for two days at 15 deg.C/10%), is within the range of -30-+100muC/g, is preferable. Thus, when the silica having great positive triboelectrifying properties is used, an image having a little much fogging is obtained. The quaternary ammonium salt used as a part of the covering agent of the carrier is expressed by the following equation. (A- shows the negative ion except the halogen ion. |
