A toner, a method of and an apparatus for preparing a permanently-charged
electret toner, including discharging a solution or dispersion including
a resin and a colorant through a nozzle vibrating at a constant frequency
to form a droplet; applying a direct potential to an electrode facing the
nozzle to positively or negatively charge the droplet by an induction
phenomenon to form a charged droplet; and drying and solidifying the
charged droplet to be permanently charged.