Patent ID: 6387580
Filing Date: 2002-05-14
Classification: G03G

Abstract:
A full-color image-forming method comprising the steps of:forming toner images of black toner on a recording medium; and superposing respective toner images of yellow toner, magenta toner and cyan toner on the back toner-images so that the black toner-images are positioned as a lowest under-part on the recording medium, wherein the black toner comprises black toner particles comprising at least a binder resin and a black colorant and having a standard deviation of degree of roundness of not more than 0.045; the yellow toner comprises yellow toner particles comprising at least a binder resin and a yellow colorant and having a standard deviation of degree of roundness of not more than 0.045 and an average degree of roundness larger than that of the black toner particles, the magenta toner comprises magenta toner particles comprising at least a binder resin and a magenta colorant and having a standard deviation of degree of roundness of not more than 0.045 and an average degree of roundness larger than that of the black toner particles, the cyan toner comprises cyan toner particles comprising at least a binder resin and a cyan colorant and having a standard deviation of degree of roundness of not more than 0.045 and an average degree of roundness larger than that of the black toner particles, and wherein the binder resin contained respectively in the yellow toner particles, the magenta toner particles and the cyan toner particles has a glass transition point ranging from 55 to 75Â° C., a softening point ranging from 95 to 120Â° C., a number-average molecular weight ranging from 2,500 to 6,000 and a ratio of weight-average molecular weight/number-average molecular weight of 2 to 8.