Heat treatment apparatus and method of obtaining toner

A heat treatment apparatus for heat-treating powder particles each containing a binder resin and a colorant, the heat treatment apparatus comprising:

• (1) a treatment chamber having a cylindrical shape, in which the powder particles are heat-treated;
• (2) a powder particle supply unit for supplying the powder particles to the treatment chamber;
• (3) a hot air supply unit for heat-treating the supplied powder particles;
• (4) a cold air supply unit for cooling the heat-treated powder particles;
• (5) a regulating unit for regulating a flow of the supplied powder particles, the unit being provided in the treatment chamber;
• and
• (6) a collection unit for collecting the heat-treated powder particles from a discharge port provided on a lower end part side of the treatment chamber,
• wherein:
• the regulating unit comprises a columnar member having a substantially circular cross-section, the member being placed on a center pole of the treatment chamber to protrude from a lower end part to an upper end part of the treatment chamber;
• the hot air supply unit is provided so that the hot air to be supplied is rotated along an inner wall of the treatment chamber;
• the discharge port of the collection unit is provided in an outer circumferential portion of the treatment chamber to keep a rotation direction of the powder particles;
• at least one protrusion with a height of 2 mm or more and 50 mm or less is provided in a region on a downstream side of the powder particle supply unit and on an upstream side of the cold air supply unit in at least one of an inner wall surface of the treatment chamber and an outer wall surface of the regulating unit;
• and
• the heat treatment apparatus has a cross-section plane,
• the cross-section plane
• being perpendicular to a center axis of the treatment chamber, and situated at the region where said protrusion is provided, and Dmin and Dmax satisfy the following relation
• 0.50≦Dmin/Dmax<1.0
• where,
• Dmin represents a minimum value of the distance of a gap between the treatment chamber and the columnar member measured in the cross-section plane, and
• Dmax represents a maximum value of the distance of a gap between the treatment chamber and the columnar member measured in the cross-section plane.