Abstract: A method for producing a barium titanate-based powder, the method including: step a of spraying a raw material including a barium titanate-based compound into a high-temperature field heated to a temperature equal to or higher than a melting point of the compound to form barium titanate-based particles; and step b of heating a powder including the barium titanate-based particles formed in step a at 700 to 1300° C.

Abstract: A method for producing a barium titanate-based powder, the method including: step a of spraying a raw material including a barium titanate-based compound into a high-temperature field heated to a temperature equal to or higher than a melting point of the compound to form barium titanate-based particles; step b of calcining a powder including the barium titanate-based particles formed in step a; and step c of washing a calcination product obtained in step b with a water-based washing liquid.

Abstract: Provided is an external additive for toner, which is suitable for producing a toner having excellent storage stability and chargeability. A silica fine powder suitable for being added to the external additive for toner is also provided. The silica fine powder has a specific surface area of 15 m2/g or more and 90 m2/g or less, a loose bulk density of 0.09 g/cm3 or more and 0.18 g/cm3 or less, a carbon content of 0.25 wt % or more and 0.90 wt % or less, and a hydrophobicity of 60% or more and 75% or less. It is preferable that a ratio (A)/(B) of the loose bulk density of the silica fine powder after surface treatment (A) to a loose bulk density of the silica fine powder before the surface treatment (B) be 1.05 or more and 1.60 or less.

Abstract: Provided is an external additive for toner, which is suitable for producing a toner having excellent storage stability and chargeability. A silica fine powder suitable for being added to the external additive for toner is also provided. The silica fine powder has a specific surface area of 15 m2/g or more and 90 m2/g or less, a loose bulk density of 0.09 g/cm3 or more and 0.18 g/cm3 or less, a carbon content of 0.25 wt % or more and 0.90 wt % or less, and a hydrophobicity of 60% or more and 75% or less. It is preferable that a ratio (A)/(B) of the loose bulk density of the silica fine powder after surface treatment (A) to a loose bulk density of the silica fine powder before the surface treatment (B) be 1.05 or more and 1.60 or less.

Abstract: Provided is a suitable toner external additive which has an excellent spacer effect, without causing image defects in repeated image formation and which is suitable in preparing a toner with stable printing properties and to provide a fine spherical silica powder suitable for adding to the toner additive. A fine spherical silica power having an average particle size measured by a laser diffraction/scattering distribution measuring apparatus of 0.090 ?m or more and 0.140 ?m or less, a particle content ratio of 5.0% by mass or more and 25.0% by mass or less when the particle diameter is 0.150 ?m or more, and a particle content ratio of 1.0% by mass or less when the particle diameter is 0.300 ?m or more.

Abstract: To provide an alumina powder having an improved flowability, a process for its production, and a resin composition employing it. An alumina powder which has an ?-phase content of at most 40% as measured by the following method, an average circularity of at least 0.