| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent decrease in the image density and resolution of a toner image and occurrence of fog and to increase the transfer efficiency. SOLUTION: The ferrite particles containing an ammonium salt-based charge controlling agent is prepared by mixing a salt containing iron, solvent and hydroxides of alkali metals to obtain a reaction mixture containing a ferrite and byproduct, extracting the ferrite from the mixture, mixing the ferrite with an aqueous solution of ammonium salt and one or more kinds of sulfonic acid compounds, metal acids, isopolyacids and heteropolyacids, and refining the obtained ferrite containing an ammonium salt-based charge controlling agent. Thereby, the ferrite particles (1) containing an ammonium salt-based charge controlling agent contain the high purity ferrite (2), and the charge controlling agent (3) is uniformly dispersed in the toner.</p> |
