MAGNETIC TONER Russian patent published in 2015 - IPC G03G9/83 G03G9/87 

FIELD: chemistry.

SUBSTANCE: magnetic toner contains magnetic toner particles which contain resin binder and a magnetic base and inorganic fine particles present on the surface of the magnetic toner particles. The inorganic fine particles present on the surface of the magnetic toner particles comprise metal oxide fine particles, the metal oxide fine particles comprising silicon dioxide fine particles and optionally titanium oxide fine particles and aluminium oxide fine particles. Content of the silicon dioxide fine particles is at least 85 wt % relative to the total weight of the silicon dioxide fine particles, titanium oxide fine particles and aluminium oxide fine particles. A coverage ratio A (%) is a ratio of the coverage of the surface of the magnetic toner particles by the inorganic fine particles and a coverage ratio B (%) is ratio of coverage of the surface of the magnetic toner particles by the inorganic fine particles which are fixed to the surface of the magnetic toner particles. The magnetic toner has a coverage ratio A, a coefficient of variation of coverage ratio A, a ratio of the coverage ratio B to coverage ratio A and a compression ratio in a specific range.

EFFECT: obtaining toner which is capable of yielding a high density image without tinting.

4 cl, 4 tbl, 9 dwg, 63 ex