MAGNETIC TONER

摘要

The magnetic toner includes magnetic toner particles comprising a binder resin and a magnetic body and inorganic fine particles present on the surface of the magnetic toner particles, wherein;the inorganic fine particles present on the surface of the magnetic toner particles comprise metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein;

when a coverage ratio A (%) is a coverage ratio of the magnetic toner particle's surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particle' surface by the inorganic fine particles that are fixed to the magnetic toner particle's surface, the magnetic toner has a coverage ratio A, a coefficient of variation on the coverage ratio A, a ratio of the coverage ratio B to the coverage ratio A, and a compression ratio in a specific range.

主权项

1. A magnetic toner comprising
magnetic toner particles comprising a binder resin and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein; the inorganic fine particles present on the surface of the magnetic toner particles comprise metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein; when a coverage ratio A (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles that are fixed to the magnetic toner particles' surface, the magnetic toner has: i) a coverage ratio A of at least 45.0% and not more than 70.0% and a coefficient of variation on the coverage ratio A of less than 10.0%, ii) a ratio [coverage ratio B/coverage ratio A] of the coverage ratio B to the coverage ratio A of from at least 0.50 to not more than 0.85, and iii) a compression ratio obtained by the following formula (1) of from at least 38% to not more than 42%:
compression ratio(%)={1−(bulk density/packed bulk density)}×100.  formula (1):