| 摘要 |
PURPOSE:To obtain a toner for low temp. fixation having durability which causes no toner deterioration such as contamination on a paper by adding externally resin particles of high melting point, charge controlling agent and fluidity improving agent at least on the surface of the toner core of low melting point, treating the core with a solvent to form a resin coating layer of high melting point. CONSTITUTION:The binder component 1 and colorant 2 are kneaded 7 and pulverized 8 into particles as the toner core 9. The binder component 1 is low-melting point resin, wax, etc. The charge controlling agent 4 is Nigrosine, metal lake pigment, etc., and the fluidity improving agent 5 is a fine powder of titanium oxide, zinc oxide, etc. The coating treatment 12 is done by dispersing the toner cores on which the resin particles are deposited externally in a solvent if the resin particle-solvent system has slow dissolution rate, and by subecting the dispersion to filtering and drying or to spray drying. For the system of high dissolution rate, the toner cores are treated with solvent vapor or solvent mist, or a dispersion liquid of the toner cores on which resin particles are deposited externally in a solvent which does not dissolve the core 9 nor resin particles 3 is mixed with a solvent 6 which dissolves the resin particles 3 just before the nozzle and then spray-dried to form a dry film. |
