A developer includes black toner particles and carrier particles, the
black toner particles including at least one binder, at least one black
colorant and one or more external additives, wherein the toner particles
comprise from about 7 to about 15 pph of the developer, and wherein the
toner particles exhibit a triboelectric charge of from about -25 to about
-50 .mu.C/g at toner particle concentrations of about 7 to about 15 pph
of the developer. The developer is ideally suited for use in a high speed
(greater than 100 prints per minute) semiconductive magnetic brush
development apparatus. Preferably, the black toner particles include a
styrene acrylate binder, and the external additives include from about
1.3 to about 2.1% by weight of the toner particles of a first silica
having an average particle size of from about 35 to about 45 nm, from
about 0.5 to about 1.0% by weight of the toner particles of a second
silica having an average particle size of from about 135 to about 160 nm,
and from about 0.2 to about 0.5% by weight of the toner particles of a
titania having an average particle size of from about 35 to about 45 nm,
with an external additive toner surface area coverage of from about 25 to
about 45%.