PURPOSE: To stably obtain adequate triboelectrification quantity and sufficient image density and to obtain a sharp image small in ground fog by reducing the average particle diameter of silica prepared by both of dry and wet processes and enhancing the hydrophobicnesses of both silicas.
CONSTITUTION: The additive agents comprise the dry process silica and the wet process silica, and the dry process silica has a hydrophobicness of 60 - 90% and the wet process silica has that of 50 - 80% and the average particle diameters of both silicas are 0.05 - 5μm, and contain no coarse silica particles of ≥10μm particle diameter, thus permitting the obtained toner to be enhanced in fluidity, to form a uniform and sharp image freed of partial dropout of transfer and poor transfer and small in ground fog, and to obtain an adequate triboelectrification quantity and stable sufficient image density.
NAKAYAMA NOBUHIRO
ASAHINA YASUO
CHIBA SHUNICHI
OKAMOTO YOSHINAO
