| 摘要 |
PURPOSE:To prevent trouble of dispersion of an amt. of charge generated on the surfaces of toner particles even when a positive charge controlling dye is used, development fog, toner scattering, carrier staining, etc., and further, deterioration of efficiency of toner image transfer in high humidity, and to make durable for a long-term storage, by adding fine silica powder synthesized by a wet method, and synthesizing a magnetic material by the wet method. CONSTITUTION:Anhydrous silicon dioxide, and silicic acid compds. are all used for fine silica powder. Its particle diameter is in the range of 0.01-2mum as an average primary particle diameter. When it is added to developer by 0.1-3wt% of developer, it exhibits positive chargeability having superior stability. It is added in a state of 0.01-3wt% fine silica powder being attached onto the surfaces of the toner particles. This powder contg. >=85% silica is preferable, it has minute pores in the inside, and an amt. of water combined with the silanol groups of the surface of the silica by van der Waals force remains comparatively stable against change of the environment. |
