HYDROPHOBIC SPHERICAL SILICA FINE PARTICLE, METHOD FOR PRODUCING THE SAME AND TONER EXTERNAL ADDITIVE FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT USING THE SAME

摘要

PPROBLEM TO BE SOLVED: To provide a hydrophobic spherical silica fine particle useful as a toner external additive and capable of improving the environmental stability of electrostatic charge of a toner. PSOLUTION: The hydrophobic spherical silica fine particle is obtained by a hydrophobic treatment comprising: introducing an RSP4/SPSiOSB3/2/SBunit (wherein RSP4/SPis a 1-20C monovalent hydrocarbon group) into a surface of a hydrophilic spherical silica fine particle comprising an SiOSB2/SBunit obtained by hydrolyzing and condensing at least one compound selected from the group consisting of tetrahydrocarbyloxysilane compounds represented by the general formula (1): Si(ORSP1/SP)SB4/SB(1) (wherein RSP1/SPs are the same or different and each is a 1-6C monovalent hydrocarbon group) and partial hydrolysis/condensation products thereof; and further introducing an RSP6/SPSB3/SBSiOSB1/2/SBunit (wherein RSP6/SPs are the same or different and each is a 1-20C monovalent hydrocarbon group). The hydrophobic spherical silica fine particle has a carbon content of 2-5 mass%, a hydrocarbyloxy group content of 0.3-5 mass% and a particle diameter of 0.01-5 μm. PCOPYRIGHT: (C)2011,JPO&INPIT