Dry electrostatographic developer composition.

摘要

A negatively-chargeable dry electrostatographic developer is disclosed containing fluorinated inorganic microparticles, and toner particles comprising an acidic binder resin having an acid value between 10 and 30 mg KOH/g and not comprising (a) charge-controlling agent(s). The developers according to this invention show excellent fluidity and have improved negative chargeability. According to a preferred mode, fluorinated silica-type microparticles are added to the developer as free flowing additive in an amount of 0.1 to 5% by weight with respect to the toner, which preferably comprises an acidic carbon black.