| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain magnetic particles having a high frictional electric charge, a narrow particle diameter distribution and a necessary particle shape and useful for producing toners, printing inks or inks for ink jet printers, and to provide a method for producing the magnetite particles. SOLUTION: This magnetic iron oxide has a Fe content of 45-73wt.%, a brightness (L*) of 45.0 to 65.0 CIELAB units, a color cast (a*) of -0.5 to 1.5 CIELAB units, and a color cast (b*) of -1.0 to -7.0 CIELAB units, and contains one or more kinds of auxiliary compounds selected from the group consisting of the oxides, hydroxides, hydrated oxides and salts of lithium, sodium, potassium, magnesium, calcium, strontium, barium, manganese and zinc metals, organic zirconium (IV) compounds, organic cerium (IV) compounds, and organic tin (IV) compounds in such an amount of 0.1-5wt.% as increasing the frictional electric charge of the raw materials (not including an additive) by at least 30%.</p> |
