| 摘要 |
PURPOSE:To obtain toner for low temp. fixation having durability which causes no toner deterioration such as contamination of a printing paper by depositing externally resin particles of high melting point at least on the surface of toner cores of low melting point, treating the cores with a solvent in which a charge controlling agent and fluidity improving agent are dispersed in order 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 cores 9. Then resin particles 3 are added 10 externally to the core surface by deposition to obtain the toner core 11 with deposition of resin particles. The particles 3 are resin having higher melting point than the binder component 1 of the inner core 9. The charge controlling agent 5 and fluidity improving agent 6 are dispersed 12 in the solvent with a homogenizer, colloid mill, etc. The coating treatment 12 is done by dispersing the toner core 11 having deposition of resin particles in a solvent when the resin particle- solvent system has slow dissolution rate, and then the dispersion is filtered and dried or spray-dried. For the system of high dissolution rate, the toner core 9 is treated with a solvent mist or by mixing a dispersion liquid dissolving the particles 3 and the dispersion liquid of the toner cores having deposition of resin particles in a solvent which does not dissolve the resin particles 3 nor the inner core 9 just before the nozzle and then formed into a dry film by spray drying. |
