| 摘要 |
PURPOSE:To obtain a toner preventing offset phenomenon, and having superior resolution and sharpness, by adding a mixture of specified resins high and low in molecular weight. CONSTITUTION:An alpha,beta-unsaturated ethylenical monomer is polymerized in an aqueous medium to give a higher polymer having >=150,000 weight average molecular weight and 30-70 deg.C glass transition point. Then, a polymerization composition consisting of an alpha,beta-unsaturated ethylenical monomer, said polymer, a colorant, a charge controller, a polymerization initiator, etc. is dispersed into water, suspended at a high agitation speed of 3,000-10,000 rotational frequency in presence of a dispersion stabilizer, and polymerized in the conditions of low agitation of 100-800rpm rotational frequency and 45-85 deg.C, thus obtaining spherical polymer particles for use in the entitled toner having a ratio of longer diameter (a)/shorter diameter (b) as follows: 1.00<=a/b<=1.05, and 1-30mum diameter, containing the particles within main particle diameter + or -3mum by >=70wt%, and being a uniform mixture of resins higher and lower in molecular weight at >=3.5 weight average molecular weight/number average molecular weight ratio. |
