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

• Main Authors: MUROTA; MASAMICHI, SHIRONO; HIROKUNI, KOMAI; EIJI, ISHIBASHI; NARUYASU
• Format: Patent
• Language: English
• Published: 20.06.2000
• Edition: 7
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

A fine powder of a hydrophobic metal oxide is provided which is produced through surface treatment of fine powder of a metal oxide with an epoxy compound and an alkylsilazane or ammonia thereby ring-opening the epoxy groups in the surface of the fine powder followed by introducing an amino group and an alkylsilyl group, or an amino group into the ring-opened epoxy groups. The fine hydrophobic metal oxide powder has good dispersability, flowability and electrification properties, and has good time-dependent stability. A toner composition for electrophotography that contains the fine hydrophobic metal oxide powder has stable and good imaging capabilities for a long period of time. Also provided is a method for modifying the surface of the fine metal oxide powder with a surface modifier, in which ammonia is introduced into the reaction system prior to the treatment of the fine powder with the surface modifier.