| 摘要 |
PURPOSE:To obtain a titled toner preventing offset phenomenon, having superior resolution and sharpness, and restraining fog, by adding a resin consisting of components having high and low specified molecular weights. CONSTITUTION:An alpha,beta-unsaturated ethylenical monomer is polymerized in an aqueous medium to give a higher polymer of >=150,000mol.wt. A polymerization composition consisting of an alpha,beta-unsaturated ethylenical monomer, said higher polymer, a colorant, a charge controller, a polymerization initiator, etc. is suspended by stirring the mixture at a speed as high as 3,000-10,000 rotational frequency in presence of a dispersion stabilizer, the agitation speed is lowered to 100-800 rotational frequency to polymerize it at 40-85 deg.C, resulting in forming a polymer composed of spherical particles having a ratio of longer diameter (a)/shorter diameter (b) as follows: 1.00<=a/b<=1.05, and 1-30mum diameter, and containing particles within main particle diameter + or -3mum by >=70wt%, and consisting of 5-50wt% higher molecular weight polymer component and 95-5wt% lower molecular weight polymer component having <=150,000 weight average molecular weight. A ratio of weight average molecular weight/number average molecular weight of this main resin is >=3.5. This resin is used for the toner in the title. |
