| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a carrier which is not crushed by the stress in an actual machine, which prevents carrier deposition, which is suitable for obtaining a high-quality image, or which keeps characteristics for an extremely long period of time with little change over time. <P>SOLUTION: The carrier for an electrophotographic developer comprises a manganese ferrite core material and at least a coating layer applied on the surface of the core and satisfies the following conditions. (1) After the carrier is magnetically held on a cylindrical sleeve and detached under specified conditions, the elemental analysis results in that the average M of M2/(M1+M2), wherein M1 (mol%) is the proportion of an iron element in one carrier particle and M2 (mol%) is the proportion of a manganese element, ranges 0.10 to 0.45, and that particles having a size as smaller than 0.6 time of the average M are included by ≤10 % in number. (2) The carrier has 25 to 65 μm weight average particle size (D4) and contains particles of ≤12 μm by ≤0.3 wt.%. (3) The ratio D4/D1 of the weight average particle size to the number average particle size (D1) ranges 1 to 1.3. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
