Developer includes toner formed of base particles containing at least a binder resin. The base particles have surfaces coated with an additive agent, and the toner has a volume average particle size between 3.9 .mu.m and 6.1 .mu.m. The developer further includes agglomerates in an amount between 0.01 wt % and 0.10 wt %. The agglomerates have a volume average particle size between 75 .mu.m and 100 .mu.m.