Fine powder of hydrophobic metal oxide, method for producing it, and toner composition for electrophotography

摘要

The present invention is concerned with a method for producing a fine powder of a surface-modified metal oxide, which comprises surface treatment of fine powder of a metal oxide with a silane coupling agent having at least one epoxy group in the molecule, wherein ammonia is added to introduce an amino group into the epoxy groups in the surface of said fine metal oxide powder. The fine powder produced in accordance with the method of the invention has good dispersibility, flowability and electrification properties, and has good imaging properties. The present invention also relates to a method for producing a toner composition for electrophotography using the fine powder of a surface-modified metal oxide obtainable by the method of the invention.