Patent ID: 7517631

Claim:
A method for manufacturing a polymerized toner comprising: (1) forming colored polymer particles including a step for polymerizing a monomer composition containing at least a colorant and a polymerizable monomer in an aqueous dispersion medium, (2) washing said colored polymer particles, and (3) recovering said colored polymer particles by filtering and drying, the colored polymer particles of step (2) being washed in a circulation washing manner using a continuous pressurizing filter for concentrating a dispersion, said filter provided with (A) a drum having an inlet for a dispersion and an outlet for the resulting dispersion concentrated by filtration, (B) stirring means comprising a plurality of stirring plates rotatably supported by a shaft of said drum, the shaft being driven and rotated by a motor along the axial direction, and said plates being fixed to the shaft at a predetermined interval, and (C) filtering means comprising a plurality of filter plates mounted on an internal wall of said drum so as to be arranged alternately with said stirring plates at a predetermined interval from each other in the axial direction, the filter plates having a hole through which the shaft is passed, and having channels through which a filtrate can pass, wherein a dispersion containing colored polymer particles in step (1) is supplied by pressure to the inlet of said continuous pressurizing filter from a slurry tank that stores said dispersion, said dispersion is filtered in said continuous pressurizing filter while stirring thereby forming a concentrated dispersion, the concentrated dispersion is fed back to said slurry tank from said outlet, a washing solution in a quantity equivalent to the quantity of the filtrate obtained by filtration is added to said slurry tank to dilute said concentrated dispersion, with the addition of the washing solution being controlled according to information from a liquid level gauge in the slurry tank, and the dispersion after being diluted by said washing solution is circulated in said continuous pressurizing filter.