| 摘要 |
PURPOSE:To enhance storage stability, fixability, charging characteristics against humidity change using a small amount of silica, by polymerizing a monomer in the presence of hydrophobic silica up to 10wt% of the monomer by suspension or block polymerization, and pulverizing the polymer to prepare a toner containing the silica. CONSTITUTION:A monomer, such as styrene or a mixture of monomer with 0.01- 5wt% hydrophobic silica, such as ''Aerosil R-972 '' made by Nippon Aerosil K.K. added is mixed with additives, such as 0.1-5wt% monomer for cross-linking, a colorant, e.g., carbon black, a magnetic powder, a polymerization initiator, etc., when necessary, and suspension-polymerized to give grains, or block-polymerized and pulverized to form a silica-containing toner. Not only a monomer having a polymerizable unsaturated group but also a monomer for preparing a condensation polymer, such as polyamide or polyester may be used and silica is added to this condensation polymer. The polymer is prepared so as to have 100-170 deg.C softening point and 40-110 deg.C glass transition point, permitting a toner to have high offset preventing performance. |
