| 摘要 |
<p>PURPOSE: To accomplish a high quality image by using a toner in which an external additive consisting of a negatively charged hydrophobic silica particulates whose surface is treated by a specific way is added. CONSTITUTION: In a toner consisting of at least a binding resin, a coloring agent particulates, and an external additive, the external additive is constructed of at least the first inorganic particulates, which is provided with an average particulate diameter of 0.05-1.0μm and is formed by means of a hydrothermal synthesis method or an oxalic acid method, the second inorganic particulates, which is provided with an average particulate diameter of 1.0-5.0μm and is formed by means of a solid phase method, and a hydrophobic silica particulates, in which a BET specific surface area based on nitrogen adsorption is 50-350m<2> /g and the surface is treated by means of silicone oil. In addition, a sphericity of the first inorganic particulates is 1.0-3.0, while that of the second inorganic particulates is 3.0-6.0. The first and the second inorganic particulates are individually made of a titanate particulates or a zirconate particulates.</p> |
