PURPOSE: To obtain a toner having superior characteristics, by adding a fatty acid- modified nigrosine to a copolymer obtained by aqueous-suspension polymerizing butyl methacrylate and styrene in presence of specified inorganic and organic dispersion stahilizers and a neutral water-soluble inorganic salt.
CONSTITUTION: One pt.wt. butyl methacrylate and 1W4pts.wt. styrene are aqueous-suspension polymerized in presence of basic tricalcium phosphate powder bt 0.1W0.5pt.wt. per 100pts.wt monomer mixture and sodium dodecylbenzenesulfonate by 0.01W0.035pt.wt. per said 1pt.wt. calcium salt for stabilizing the suspension, and a water-soluble neutral salt, such as NaCl by 0.02W0.1pt.wt. per 100pts.wt. monomer mixture for preventing deterioration of transparency and electric characteristics of the polymer particles. Five pts. wt. fatty acid-modified nigrosine dye is added to 85pts.wt. copolymer particles thus obtained, together with carbon black etc., mixed by fusing, and after cooling, classified to obtain a 5W30μ toner.
MORIBE ISAMU
HIGASHIDA OSAMU
