Electrophotographing dry-type toner and production method therefor

A dry toner for electrophotography comprising colored resin particles with releasing agent particles dispersed in a binder resin, and encapsulating resin particles fixedly fused to the surface of each colored resin particle to form a resin coating layer thereon, characterized in that the releasing agent particles dispersed in each colored resin particle have a particle diameter distribution such that the particle diameter of releasing agent particles dispersed in the vicinity of the surface of each colored resin particle is larger than the particle diameter of releasing agent particles at a central site of the colored resin particle.

A dry toner for electrophotography comprising colored resin particles with releasing agent particles dispersed in a binder resin, and encapsulating resin particles fixedly fused to the surface of each colored resin particle to form a resin coating layer thereon, wherein each colored particle is coated with a resin coating layer with a releasing agent layer interleaved therebetween.

A process for producing an electrophotographic dry toner, which comprises the steps of adding 0.5 parts by weight to 10 parts by weight of a releasing agent non-compatible with a binder resin to 100 parts by weight of the binder resin and dispersing the releasing agent therein with a coloring agent added thereto, then grinding the resultant dispersion by fine grinding means into colored resin particles, and finally treating the colored resin particles in a hot-air stream for their re-dispersion so that the releasing agent particles dispersed in each colored resin particle have a particle diameter distribution such that the particle diameter of releasing agent particles dispersed in the vicinity of the surface of each colored resin particle is larger than the particle diameter of releasing agent particles at a central site of the colored resin particle.

A for producing an electrophotographic dry toner, which comprises the steps of adding 0.5 parts by weight to 10 parts by weight of a releasing agent non-compatible with A binder resin to 100 parts by weight of the binder resin and dispersing the releasing agent therein with a coloring agent added thereto, then grinding the resultant dispersion by fine grinding means into colored resin particles, then uniformly fixing encapsulating resin particles onto the surface of the colored resin particles by mechanical impact or a dry mechanochemical method and finally treating the colored resin particles in a hot-air stream so that the encapsulating resin particles are fused onto the surface of the colored resin particles to form a resin coating layer thereon, and the releasing agent particles dispersed in each colored resin particle have a particle diameter distribution such that the particle diameter of releasing agent particles dispersed in the vicinity of the surface of each colored resin particle is larger than the particle diameter of releasing agent particles at a central site of the colored resin particle.

A process for producing an electrophotographic dry toner, which comprises the steps of adding 0.5 parts by weight to 10 parts by weight of a releasing agent non-compatible with the binder resin to 100 parts by weight of the binder resin and dispersing the releasing agent therein with a coloring agent added thereto, then grinding the resultant dispersion by fine grinding means into colored resin particles, then uniformly fixing encapsulating resin particles onto the surface of the colored resin particles by mechanical impact or a dry mechanochemical method and finally treating the colored resin particles in a hot-air stream so that the encapsulating resin particles are fused onto the surface of the colored resin particles to form a resin coating layer thereon, and the colored resin particles are coated with the resin coating layer with a releasing agent layer interleaved therebetween.

A process for producing an electrophotographic dry toner, which comprises the steps of adding 0.5 parts by weight to 10 parts by weight of a releasing agent non-compatible with a binder resin to 100 parts by weight of the binder resin and dispersing the releasing agent therein with a coloring agent added thereto, then grinding the resultant dispersion by fine grinding means into colored resin particles, then heating the colored resin particles in a hot-air stream at a temperature higher than the melting point of the releasing agent to form a releasing agent layer on their surfaces, and finally uniformly fixing encapsulating resin particles onto the surface of the colored resin particles by mechanical impact or a dry mechanochemical method.