Polymer particles and toner for electrophotography using the polymer particles

A toner comprising polymer particles which are substantially spherical and have protrusions on the surface thereof, with such a particle size distribution that the volume mean diameter dv thereof is 1.gtoreq.dv.gtoreq.15 (.mu.m), and the ratio of said volume mean diameter dv to the number mean diameter dn thereof, that is, dv/dn, is 1.gtoreq.dv/dn.gtoreq.1.2, and are uniformly dyed to the inside thereof.

Polymer particles which are substantially spherical and have protrusions on the surface thereof, with such a particle size distribution that the volume mean diameter dv thereof is 1.gtoreq.dv.gtoreq.15 (.mu.m), and the ratio of said volume mean diameter dv to the number mean diameter dn thereof, that is, dv/dn, is 1.gtoreq.dv/dn.gtoreq.1.2, said polymer particles being produced by a polymerization method comprising the steps of:

• polymerizating a vinyl monomer in the presence of a polymeric dispersing agent in a hydrophilic organic liquid in which said vinyl monomer is soluble, but in which a polymer formed from said vinyl monomer swells or is substantially insoluble, optionally in the presence of a cross-linking agent and a chain transfer agent, thereby preparing first polymer particles;
• and
• continuing the polymerization with the addition thereto of a vinyl monomer which, when polymerized, provides a polymer with a glass transition point higher than that of said first polymer particles, and an anionic monomer or a cationic monomer, thereby producing polymer particles which are substantially spherical and have protrusions on the surface of each polymer particle, with a narrow particle size distribution.

A toner comprising polymer particles which are substantially spherical and have protrusions on the surface thereof, with such a particle size distribution that the volume mean diameter dv thereof is 1.gtoreq.dv.gtoreq.15 (.mu.m), and the ratio of said volume mean diameter dv to the number mean diameter dn thereof, that is, dv/dn, is 1.gtoreq.dv.gtoreq.1.2, and are uniformly dyed to the inside thereof, said polymer particles being produced by a polymerization method comprising the steps of:

• polymerizing a vinyl monomer in the presence of a polymeric dispersing agent in a hydrophilic organic liquid in which said vinyl monomer is soluble, but in which a polymer formed from said vinyl monomer swells or is substantially insoluble, optionally in the presence of a cross-linking agent and a chain transfer agent, thereby preparing first polymer particles;
• and
• continuing the polymerization with the addition thereto of a vinyl monomer which, when polymerized, provides a polymer with a glass transition point higher than that of said first polymer particles, and an anionic monomer or a cationic monomer, thereby producing polymer particles which are substantially spherical and have protrusion on the surface of each polymer particle, with a narrow particle size distribution.