Patent ID: 6010811
Filing Date: 2000-01-04
Classification: G03G

Abstract:
A two-component developer for developing an electrostatic image, comprising: at least a toner and a magnetic carrier; whereinthe toner has a weight-average particle size D4 of at most 10 .mu.m and a number-average particle size D1 satisfying D4/D1.ltoreq.1.5; andthe magnetic carrier has an electrical resistivity of at least 1.times.10.sup.12 ohm.cm at an electric field intensity of 5.times.10.sup.4 volts/meter, and comprises composite particles comprising a mixture of magnetic iron compound particles, non-magnetic metal oxide particles, and a binder comprising a phenolic resin; the composite particles containing the magnetic iron compound and the non-magnetic metal oxide in a total proportion of 80-99 wt. %; the magnetic iron compound particles having a number-average particle size r.sub.a, the non-magnetic metal oxide particles having (i) a number-average particle size r.sub.b satisfying r.sub.b /r.sub.a >1.0 and (ii) a higher resistivity than the magnetic iron compound particles, each of the composite particles containing the non-magnetic metal oxide particles and the magnetic iron compound particles at and below the surface of the composite particle.