Patent ID: 7258960

Claim:
A method of producing toner for developing an electrostatic latent image by a centrifugal concentrating device in which a centrifugal force is caused from a central region to a peripheral region and which comprises an inlet section to feed a slurry to the central region, a precipitating plate extending from the central region to the peripheral region and an accommodating section to accommodate a predetermined amount of a slurry at the peripheral region, the method comprising the steps of: a feeding step of feeding a slurry containing toner particles, aqueous medium and impure fine particles having a specific gravity smaller than that of the toner particles to the inlet section; an applying step of applying centrifugal force of 5000 G to 15000 G to the slurry with the centrifugal concentrating device having the precipitating plate with which the toner particles are precipitated from the slurry toward the peripheral region of the centrifugal concentrating device so that the precipitated toner particles are accumulated as a concentrated slurry in the accommodating section of the centrifugal concentrating device; a delivering step of delivering impure fine particles and aqueous medium to the outside of the centrifugal concentrating device, and a discharging step of automatically discharging the concentrated slurry containing the accumulated toner particles from the accommodating section, wherein the number of toner particles holding free releasing agent particles attached to the surfaces of the toner particles is 3 or less per 100 discharged-toner particles.