Patent ID: 6156469
Filing Date: 2000-12-05
Classification: G03G

Abstract:
A developing agent, comprising:a toner containing at least a binder resin, a coloring agent and a 2:1 metal complex salt compound represented by general formula (1): ##STR13## where X represents --CONHPh group, Y represents --SO.sub.2 C.sub.2 H.sub.5 group, M represents a cobalt atom, and A represents an alkaline metal or an ammonium ion, wherein said toner contains first hydrophobic silica fine particles having a first particle diameter and having a surface treated with a first hydrophobic treating agent, and second hydrophobic silica fine particles having a second particle diameter differing from said first particle diameter and having a surface treated with a second hydrophobic treating agent differing from said first hydrophobic treating agent, wherein said first hydrophobic silica fine particles have a primary particle diameter of 7 nm or less and are made hydrophobic by a treatment with a compound having a trimethyl silyl group, and said second hydrophobic silica fine particles have a primary particle diameter of 12 nm or more and treated with octyl silane, anda carrier consisting of particles of a material represented by general formula (2) and covered with a silicone resin:(MO).sub.X (Fe.sub.2 O.sub.3).sub.y ( 2)where M represents at least one metal selected from the group consisting of Mg, Mn, Fe(II), Co, Ni, Cu, Zn, Cd, Sr, and Ba, and a molar ratio of X to Y is 1.0 or less.