JP2015225318A5 - - Google Patents

Claims (8)

A magnetic toner containing magnetic toner particles containing a binder resin and a magnetic material, and inorganic fine particles,
The magnetic toner has a thermal conductivity of 0.230 W / (m · K) or more and 0.270 W / (m · K) or less,
The inorganic fine particles contain silica fine particles having a number average particle diameter (D1) of primary particles of 30 nm to 200 nm,
The magnetic toner contains 0.1 to 3.0 parts by mass of the silica fine particles with respect to 100 parts by mass of the magnetic toner particles;
The ratio of the total energy (mJ) of the magnetic toner and the true density (g / ml) of the magnetic toner, measured by a powder flowability measuring device, is 200 mJ / (g / ml). ) A magnetic toner, wherein the magnetic toner is 400 mJ / (g / ml) or less. The magnetic toner according to claim 1, wherein the magnetic toner has a dielectric loss tangent tan δ of 1.0 × 10 ⁻² or more and 2.0 × 10 ⁻² or less.   The magnetic toner according to claim 1 or 2, wherein the magnetic toner has an average circularity of 0.960 or more.   The magnetic toner according to claim 1, wherein the magnetic material is a treated magnetic material obtained by surface-treating magnetic iron oxide with a silane compound.   The magnetic iron oxide has a silicon element on the surface, and the amount of silicon eluted when the magnetic iron oxide is dissolved until the dissolution rate of the iron element reaches 5.00% by mass, the magnetic iron oxide The magnetic toner according to claim 4, wherein the toner is 0.05% by mass or more and 0.50% by mass or less as a reference.   5. The residual carbon amount derived from the silane compound after washing the treated magnetic material with styrene is 0.40% by mass or more and 1.20% by mass or less based on magnetic iron oxide. Or 5. Magnetic toner according to 5.   The magnetic toner according to any one of claims 4 to 6, wherein the silane compound is a silane compound obtained by subjecting alkoxysilane to hydrolysis until the hydrolysis rate becomes 50% or more. 8. The magnetic toner according to claim 1, wherein a volume specific heat of the silica fine particles at 50 ° C. is 5000 J / (cm ³ · K) or more and 10000 J / (cm ³ · K) or less. .