| 摘要 |
<p>The present invention pertains to a black magnetic iron oxide particle powder comprising a magnetite particle powder which is octahedral in shape, has silicon evenly distributed throughout the particle interior, and exhibits excellent blackness even when the applied coat thereof is thin. When producing a magnetic toner by using the black magnetic iron oxide particle powder in the present invention, it is possible to obtain a magnetic toner which exhibits excellent blackness. The black magnetic iron oxide particle powder is characterized by: being octahedral in shape; containing silicon in the amount of 0.19-1.90 at% calculated on a silicon element basis in relation to iron; and the silicon element solubility (Y), when the iron element solubility (X) is in the ranges of 20<X20-40≤40%, 40<X40-60≤60% and 60<X60-80≤80%, satisfying a specific relational expression comprising the iron element solubility (X) and the silicon element solubility (a) when the iron element solubility is 10%.</p> |
