| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a carrier which does not induce carrier sticking, which is suitable for forming a high-quality image, which shows little change with time and which keeps the characteristics for an extremely long time. <P>SOLUTION: The electrophotographic carrier having a coating layer on the surface of a magnetic core material satisfies the following conditions. They are: the magnetization ratio σ1/σ2, wherein σ1 is the magnetization at 1,000 Oe of the carrier detaching through an aperture within 0 to 30 minutes under specified magnetic conditions and σ2 is the magnetization at 1,000 Oe of the carrier detaching through the aperture within 30 to 60 minutes, satisfies the relation of 0.95≤σ1/σ2<1.00; the magnetization σb of the carrier and the specific gravity of the carrier satisfy specified relation; the weight average diameter and the number average diameter of the carrier are specified values and in specified relation; and when a magnetic brush of the carrier having 40% space possession rate is formed between parallel planar electrodes and an AC voltage at 1,000 Hz frequency is applied in almost the same direction as the brush, the electric resistance is a specified value and in specified relation. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
