Suspension polymerization process for producing electrophotographic toners

A process for producing toners for use in electrophotography which comprises:

• stirring a mixture of a radical polymerizable liquid monomer and carbon black in the presence of a peroxide polymerization initiator, thereby to disperse the carbon black uniformly and minutely in the monomer;
• adding a charge controlling agent powder to the monomer composition and stirring the mixture;
• adding an azobisnitrile plymerization initiator to the monomer composition;
• suspension polymerizing the monomer in an aqueous medium;
• and recovering and drying the resultant spherical polymer particles.

A process for producing toners for use in electrophotography which comprises:

• forming a mixture of a radical polymerizable monomer and carbon black dispersed therein;
• suspension polymerizing the monomer in an aqueous medium which contains polyvinyl alcohol as a suspending agent;
• saponifying the polyvinyl alcohol remaining on the resultant spherical polymer particles;
• and recovering and drying the spherical polymer particles.

A process for producing toners for use in electrophography which comprises:

• (a) a step of stirring a mixture of a radical polymerizable liquid monomer and carbon black in the presence of a peroxide polymerization initiator, thereby to disperse the carbon black minutely and uniformly in the monomer;
• (b) a step of mixing the resultant mixture with a charge controlling agent powder and stirring the mixture, thereby to disperse the powder minutely and uniformly in the monomer;
• (c) adding an azobisnitrile polymerization initiator to the resultant monomer composition, suspending the monomer composition in an aqueous medium which contains polyvinyl alcohol as a suspending agent, and polymerizing the monomer;
• (d) saponifying the polyvinyl alcohol remaining on the resultant spherical polymer particles;
• and
• (e) recovering the particles and drying the same.

A process for producing toners for use in developing electrostatic latent images which comprises:

• forming a mixture of a radical polymerizable monomer and carbon black;
• suspension polymerizing the monomer in an aqueous medium which contains polyvinyl alcohol as a suspending agent;
• suspension polymerizing the monomer in an aqueous medium which contains polyvinyl alcohol as a suspending agent;
• nitrating the polyvinyl alcohol remaining on the resultant spherical polymer particles;
• and recovering and drying the spherical polymer particles.

A process for producing toners for use in developing electrostatic latent images which comprises:

• (a) a step of stirring a mixture of a radial polymerizable liquid monomer and carbon black in the presence of a peroxide polymerization initiator, thereby to disperse the carbon black minutely and uniformly in the monomer;
• (b) a step of mixing the resultant mixture with a charge controlling agent powder and stirring the mixture, thereby to disperse the powder minutely and uniformly in the monomer;
• (c) adding an azobisnitrile polymerization initiator to the resultant monomer composition, suspending the composition in aqueous medium which contains polyvinyl alcohol as a suspending agent, and polymerizing the monomer;
• (d) nitrating the polyvinyl alcohol remaining on the resultant spherical polymer particles with an aqueous nitrating agent;
• and
• (e) recovering the particles and drying the same.