Method of producing magnetic carrier and magnetic carrier that uses this production method

A method of producing a magnetic carrier, a surface of which is coated with a resin composition, comprising a coating process step in which a surface of a magnetic carrier core is coated with particles of the resin composition by a mechanical impact force,

• wherein:
• the coating process step comprises;
• a first coating process step of mixing, dispersing, and fixing the particles of the resin composition on the surface of the magnetic carrier core;
• and
• a second coating process step, which is performed after the first coating process step, of carrying out a film-forming coating process in which the particles of the resin composition fixed on the magnetic carrier core are spread on the surface of the magnetic carrier core,
• wherein:
• the first coating process step and the second coating process step are carried out by using an apparatus provided with a rotating member having a plurality of stirring members on the surface thereof, a drive member that rotates the rotating member, and a main casing disposed so as to have a gap between an inner circumferential surface of the main casing and the stirring members,
• in the first coating process step and the second coating process step, the magnetic carrier core and the particles of the resin composition are transported by a part of the stirring members in a direction of the drive member that is one direction along an axial direction of the rotating member while being transported into the gap by a centrifugal force generated accompanying the rotation of the rotating member and are transported by another part of the stirring members in a counterdirection to the drive member that is an opposite direction to the one direction along the axial direction of the rotating member, and the coating of the surface of the magnetic carrier core with the particles of the resin composition is performed while repeating the transport in the direction of the drive member and the transport in the counterdirection to the drive member,
• wherein:
• when,
• KT (second) represents a coating process time in the first coating process step,
• KF (° C.) represents a product temperature at the finish of the coating process, and
• Tg represents a glass-transition temperature of the resin component present in the resin composition,
• the peripheral velocity of the outermost end of the stirring members during the coating process time in the first coating process step is at least 3 m/sec and not more than 7 m/sec,
• KT is at least 60 seconds and not more than 1800 seconds,
• KF satisfies KF≦Tg−40° C., and
• the peripheral velocity of the outermost end of the stirring members in the second coating process step is at least 8 m/sec and not more than 20 m/sec,
• and wherein:
• when,
• HF (° C.) represents a product temperature at the finish of the film-forming coating process in the second coating process step, and
• Tg represents a glass-transition temperature of the resin component present in the resin composition,
• HF satisfies Tg−20° C.≦HF≦Tg+20° C.