JPH0513310B

PURPOSE:To prepare a positively chargeable electrostatic image developing toner having a narrow particle diameter distribution and a proper particle diameter, by dispersing a toner material contg. a synthetic resin monomer and a polymn. initiator into a dispersion medium contg. a hydrophilic positively chargeable fine silica powder and having little compatibility with said monomer, and carrying out suspension polymn. of said monomer. CONSTITUTION:As the synthetic resin monomer, styrene or its derivs., ethylenically unsatd. monoolefins, vinyl halides, vinyl esters, etc. are usable. As the polymn. initiator, azobisisobutyronitrile (AIBN), benzoyl peroxide, lauroyl peroxide, etc. are used to polymerize the monomer. As the dispersion medium, a combination of water and a small amt. of acid, alkali, alcohol, and a dispersion stabilizer may be used. The hydrophilic positively chargeable fine silica powder may be processed with a general surface treating agent, such as a compd. represented by the general formula XmSiYn in which X is alkoxy or chlorine; m is 1, 2, or 3; Y is a hydrocarbon group having a primary, secondary, or tertiary amino group; and n is 3, 2, or 1.