RESIN-FILLED FERRITE CARRIER CORE MATERIAL FOR ELECTROPHOTOGRAPHIC DEVELOPER, FERRITE CARRIER AND ELECTROPHOTOGRAPHIC DEVELOPER USING THE FERRITE CARRIER

摘要

Disclosed are a resin-filled ferrite carrier core material for an electrophotographic developer, including a porous ferrite particle, wherein the composition of the porous ferrite particle is represented by the following formula (1), and part of (MgO) and/or (Fe₂O₃) in the following formula (1) is replaced with SrO; a ferrite carrier obtained by filling a resin in the voids of the ferrite carrier core material; and an electrophotographic developer using the ferrite carrier:; $$ \begin{array}{cc}\left(\mathrm{MgO}\right)\times \left({\mathrm{Fe}}_2O_3\right)y\left(\begin{array}{c}x=10\mathrm{mol}\%\mathrm{or}\mathrm{more}\mathrm{and}\mathrm{less}\mathrm{than}25\mathrm{mol}\%\\ y=\mathrm{exceeding}75\mathrm{mol}\%\mathrm{and}90\mathrm{mol}\%\mathrm{or}\mathrm{less}\\ x+y=100\mathrm{mol}\%\end{array}\right)& \left(1\right)\end{array}$$