Patent ID: 7910280
Filing Date: 2011-03-22
Classification: G03G

Abstract:
1. A method of producing a polymerized toner comprising: a step obtaining an aqueous dispersion of a colored resin particle by forming the colored resin particle by polymerization method; a separation and washing step obtaining a redispersion of the colored resin particle by separation and washing of the colored resin particle in the aqueous dispersion of the colored resin particle, followed by redispersing the colored resin particle into an ion-exchange water; a by-product microparticle removing step removing a by-product microparticle from the redispersion of the colored resin particle; a dewatering step obtaining a wet colored resin particle by dewatering the redispersion of the colored resin particle; and a drying step drying the wet colored resin particle, wherein, in the above-mentioned separation and washing step, a belt filter is used as a device conducting separation and washing, and the separation and washing is carried out to enhance a degree of washing of the colored resin particle until an electric conductivity of filtrate becomes 500 μS/cm or less provided that the electric conductivity is determined with respect to the filtrate obtained by such manner that the colored resin particle obtained by separation and washing with the use of the belt filter is redispersed into the ion-exchange water to prepare the redispersion of the colored resin particle with 20 weight % of solid content concentration and filtrate it, and then the colored resin particle is redispersed again into the ion-exchange water to obtain the redispersion of the colored resin particle with the predetermined solid content concentration; wherein, in the by-product microparticle removing step, pH of the redispersion of the colored resin particle with the predetermined solid content concentration is adjusted to 9-12, the by-product microparticle is removed from the redispersion of the pH adjusted colored resin particle, followed by redispersing the colored resin particle into the ion-exchange water to obtain the redispersion of the colored resin particle with the predetermined solid content concentration; wherein, in the dewatering step, an acid and/or a cationic polymer flocculant as a flocculant is added into the redispersion of the colored resin particle with the predetermined solid content concentration to aggregate the colored resin particle, followed by dewatering to obtain the wet colored resin particle.