| 摘要 |
PROBLEM TO BE SOLVED: To provide magnetic carrier configured to prevent leakage, and to improve resistance to white-spot failure and image roughness of an image, while preventing reduction in developing performance.SOLUTION: In magnetic carrier formed by coating a surface layer of a porous ferrite core material with resin, the porous ferrite core material has i) a magnetic intensity (&sgr;n) of 55 to 70Am/kg when an external magnetic field of 5000/4&pgr;(kA/m) is applied, ii) a pore volume of 60 to 120 mm/g, iii) a peak pore size of 0.40 to 0.90 μm, and iv) a particle size distribution (D50) of 25 to 60 μm. In powder x-ray diffraction measurement, the maximum peak intensity in 20deg≤2&thetas;≤40deg satisfies the following formula 1: 1.00≥P/P≥(2&sgr;n-65)/75, where Pis a maximum peak value in x-ray diffraction of the porous ferrite core material, and Pis a maximum peak value in x-ray diffraction with the same formulation as the porous ferrite core material, in a particle having a magnetic intensity of 70Am/kg when an external magnetic field of 5000/4&pgr;(kA/m) is applied. |
