Electrophotographic toner containing metal complex charge control agent

摘要

A compound having the formula: <IMAGE> (I) wherein each of R1, R2, R3 and R4 is a hydrogen atom, an alkyl group having from 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having from 6 to 20 carbon atoms and an aralkyl group having from 7 to 20 carbon atoms, and A(-) is a molybdic acid anion, a tungstic acid anion or a heteropolyacid anion containing molybdenum or tungsten atoms.