| 摘要 |
PURPOSE:To obtain an encapsulated toner suitable especially for pressure fixation and superior in development stability, durability, etc. by precipitating the first outer shell uniformly coating all the core material by adjusting pH without using any solvent dissolving the second outer shell. CONSTITUTION:A polymer having pressure fixability, such as low mol.wt. PE, is used for a core material, a magnetic powder is added in the case of a magnetic toner, the core material particles are dispersed into a soln. contg. casein and NH4OH, an aq. soln. of HCl is dropped to neutralize said soln. to uniformly precipitate said casein on the surface of each particle and thus form the first shell. Said particles are, after drying, dispersed uniformly into a DMF soln. of a styrene-dimethylaminoethyl metacrylate resin, and then water is dropped to precipitate the resin on the surface of each particle and thus form the second outer shell. When a soln. of acrylic acid polymer is used to form the first outer shell, the polymer is pptd. with a soln. of NH4OH. The encapsulated toner thus obtained is prevented from peeling off the outer shells, elution of the core material, agglomeration of the particles with each other, and offset phenomenon of the toner. |
