Patent ID: 7862974
Filing Date: 2011-01-04
Classification: G03G

Abstract:
1. A production method of a toner comprising toner particles, each of which comprises an inner layer and an outer layer covering the inner layer, the method comprising the steps of: preparing a dispersion of core particles as the inner layer and, forming the outer layer by dividing an outer layer forming resinous particle dispersion into 2 to 8 portions and adding each of the portions discontinuously into the dispersion of core particles as the inner layer, wherein the toner satisfies a), b), c), d), and e): a) a cross-sectional area ratio of the outer layer to the inner layer ranges from 0.05 to 0.46, b) the thickness of the outer layer is non-uniform, c) the average thickness (t) taken at 5 positions of the outer layer ranges from 0.2 to 1.0 μm, and is calculated according to the formula t=(t d) a glass transition point Tg of the inner layer ranges from 2 to 45° C. lower than a glass transition point Tg of the outer layer, e) the toner exhibits an average value of circularity ranging from 0.954 to 0.992, which is calculated by averaging the circularity of at least 2000 toner particles having a particle diameter of at least 1 μm, wherein the circularity of a toner particle=(peripheral length of equivalent circle)/(peripheral length of projected image of toner particle)=2π×(projected area of particlerr)