Abstract: A pulverization/classification apparatus including a cylindrical vessel having an inner wall, on a surface of which a layer including a release agent is located; a pulverizer configured to pulverize a material such as toner raw materials in the cylindrical vessel using a compressed air to prepare a particulate material; and a classifier configured to classify the particulate toner material to prepare a powder of the material. Alternatively, the inner wall of the cylindrical vessel has a circumferentially projected portion. A method for manufacturing a powder such as toners using the pulverization/classification apparatus is also provided.

Abstract: A two-step process for the production of a toner for developing electrostatic images, including a first pulverizing step wherein a toner composition containing a binder and a coloring agent is pulverized to obtain preliminarily pulverized particles having a weight average particle diameter of 20-100 &mgr;m and containing no more than 50% by weight of particles having roundness of 0.90 or less, and a second pulverizing step wherein the preliminarily pulverized particles are finely pulverized to obtain finely pulverized particles having a weight average particle diameter of 5-13 &mgr;m and containing no more than 30% by weight of particles having roundness of 0.90 or less and no more than 15%, based on the total number of particles of the finely pulverized particles, of particles having a particle diameter of 5 &mgr;m or less.

Abstract: A method of producing a toner for developing latent electrostatic images includes the steps of preliminarily grinding a toner composition having at least a binder resin and a coloring agent to prepare a preliminarily ground product, and finely pulverizing the preliminarily ground product using a pulverizer to produce toner particles, wherein the preliminarily ground product satisfies conditions (1) and (2): Dv≧D10  (1) D50<3D10  (2) wherein Dv is a weight mean diameter of the preliminarily ground product, D10 is a weight mean diameter when the cumulative number of particles reaches 10% at measurement of a cumulative particle distribution, and D50 is a weight mean diameter when the cumulative number of particles reaches 50% at measurement of the cumulative particle distribution.

Abstract: A method of producing a toner for developing latent electrostatic images includes the steps of preliminarily grinding a toner composition having at least a binder resin and a coloring agent to prepare a preliminarily ground product, and finely pulverizing the preliminarily ground product using a pulverizer to produce toner particles, wherein the preliminarily ground product satisfies conditions (1) and (2):

Abstract: A two-step process for the production of a toner for developing electrostatic images, including a first pulverizing step wherein a toner composition containing a binder and a coloring agent is pulverized to obtain preliminarily pulverized particles having a weight average particle diameter of 20-100 &mgr;m and containing no more than 50% by weight of particles having roundness of 0.90 or less, and a second pulverizing step wherein the preliminarily pulverized particles are finely pulverized to obtain finely pulverized particles having a weight average particle diameter of 5-13 &mgr;m and containing no more than 30% by weight of particles having roundness of 0.90 or less and no more than 15%, based on the total number of particles of the finely pulverized particles, of particles having a particle diameter of 5 &mgr;m or less.

Abstract: A classifying device including an upper, dispersing chamber for dispersing solid particles supplied thereto together with a carrier gas, and a lower, classifying chamber directly connected to a lower end of the dispersing chamber for centrifugally classifying the solid particles, supplied from the dispersing chamber to the classifying chamber, into relatively fine particles and relatively coarse particles. The dispersing chamber is provided with a rotor for swirling the solid particles in the dispersing chamber.

Abstract: A supersonic jet crusher of a collisional type has an injecting nozzle for injecting a jet stream into a crushing chamber; a jet stream path for supplying a crushing material into the jet stream; a collisional plate disposed in a position opposite to the injecting nozzle; a detachable jig disposed in said crushing chamber; and a secondary collisional plate detachably arranged in the detachable jig such that the crushing material collides with the collisional plate and further collides with the secondary collisional plate. Another supersonic jet crusher of a collisional type has an injecting nozzle for injecting a jet stream into a crushing chamber; a supplying port for supplying a crushing material into the jet stream; and a collisional member opposed to the injecting nozzle and having a crushing face on which the crushing material directly collides against to finely crush the crushing material.