Negatively charged electrophotographic developer

Abstract

Abstract PURPOSE:To enable uniform and intense electrostatic charge and to obtain a high quality image without causing fogging or scattering to the periphery of the edge by using fine silicic acid powder treated successively with a silane coupling agent and silicone oil. CONSTITUTION:Fine silicic acid powder is successively treated with a silane coupling agent and silicone oil. The amt. of the silicone oil used is A/25+ or -A/30 pts.wt. (A is the specific surface area of the fine silicic acid powder) per 100pts. wt. fine silicic acid powder treated with the silane coupling agent and the silicone oil has >=90% degree of hydrophobicity. Dimethyldichlorosilane, trimethylchlorosilane or allyldimethylchlorosilane may be used as the silane coupling agent. Dimethylsilicone oil, alkyl modified silicone oil or alpha- methylstyrene modified silicone oil may be used as the silicone oil. When a developer contg. the treated fine silicic acid powder is used, a high density and high quality picture image is obtd. even in an environment at high temp. and humidity or at low temp. and humidity.

Inventors

• 👤 Hitoshi Uchiide
• 👤 内出　仁志
• 👤 Tetsuya Kuribayashi
• 👤 栗林　哲哉
• 👤 Manabu Ono
• 👤 学 大野

Bibliographic Details