Magnetic developer for electrophotography

摘要

A one-component magnetic developer for electrophotography comprises single component magnetic toner particles and at least one fine particulate additive selected from hydrophobic silica, hydrophilic silica and alumina, wherein the toner particles have a specific surface area of 1.4 to 2.0 m<2>/g and a sphericity degree (DS) of 70 to 90% as defined by formula (I) $wherein\; Cc\; is\; the\; outer\; circumference\; of\; a\; circle\; having\; the\; same\; area\; as\; the\; projected\; area\; of\; the\; toner,\; and\; CT\; is\; the\; actual\; outer\; circumference\; of\; the\; projected\; plane\; of\; the\; toner.\; The\; developer\; has\; excellent\; flowability\; and\; can\; provide\; a\; high\; density\; image.$