Process for producing toner for developing electrostatic images and apparatus therefor
AssigneeCanon Kabushiki Kaisha
InventorsHitoshi Kanda, Masayoshi Kato
Life of this patent
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Abstract
A toner for producing electrostatic latent images is produced by classifying a pulverized feed material into a coarse powder and a fine powder in a first classifying means, pulverizing and recycling the coarse powder to the first classifying means, introducing the fine powder into a multi-division classifying chamber divided into at least three sections where the fine powder is classified into at least a coarse powder fraction, a medium powder fraction and a fine powder fraction. The medium powder fraction is recovered to provide a toner. The coarse powder fraction is recycled to the first classifying means.
Claims24
A process of producing toner particles for developing electrostatic latent images, comprising:
- melt-kneading a composition comprising at least a binder resin and a colorant, cooling and solidifying the kneaded product and pulverizing the solidified product to prepare a pulverized feed material;
- introducing the pulverized feed material to a first classifying means to classify the feed material into a coarse powder and a fine powder;
- introducing the classified coarse powder into a pulverization step and recycling the resultant pulverized product to the first classification means;
- introducing the classified fine powder through a supply nozzle into a multi-division classifying chamber divided into at least three sections by partitioning means so that the particles of the fine powder fall along curved lines due to the Coanda effect, wherein a coarse powder fraction comprising primarily particles having a particle size above a prescribed range is collected in a first divided section, a medium powder fraction comprising primarily particles having a particle size within the prescribed range is collected in a second divided section, and a fine powder fraction comprising primarily particles having a particle size below the prescribed range is collected in a third divided section, wherein the first divided section is located farther than the second divided section and the second divided section is located farther than the third divided section, respectively, with respect to the supply nozzle;
- and
- introducing the collected coarse powder fraction into the first classifying means together with the pulverized feed material.
An apparatus for producing a toner for developing electrostatic latent images, comprising:
- metering feeder means for metering and feeding a pulverized feed material for a toner, first classifying means for classifying the pulverized feed material into a fine powder and a coarse powder, pulverizing means for pulverizing the coarse powder classified in the first classifying means, introduction means for introducing the pulverized powder from the pulverizing means through a supply nozzle into the first classifying means, multi-division classifying means having a Coanada block for classifying the fine powder from the first classifying means into at least a coarse powder fraction, a medium powder fraction and a fine powder fraction through the Coanda effect so that the coarse powder fraction is collected in a first divided section, the medium powder fraction is collected in a second divided section and the fined powder fraction is collected in a third divided section wherein the first divided section is located farther than the second divided section and the second divided section is located farther than the third divided section, respectively, with respect to the supply nozzle, and introduction means for introducing the coarse powder fraction from the multi-division classifying means to the metering feeder means.
Dependencies are inferred from the claim text.