Patent ID: 8021813

Claim:
An electrostatic-image-developing toner, which is obtained by: adding a phosphonic acid based sequestering agent in a particle dispersion, and then being subject to aggregation, wherein the phosphonic acid based sequestering agent comprises at least one of a compound represented by the following formula (1) and a compound represented by the following formula (2): wherein each of R 1 and R 2 represents —OM, wherein M represents a hydrogen atom, an alkali metal or a quaternary ammonium; each of R 3 , R 4 and R 5 independently represents a hydroxyl group, a carboxyl group, an alkyl or alkenyl group optionally having a hydroxyl or carboxyl group at the terminal thereof, or NR 12 R 13 , wherein each of R 12 and R 13 independently represents a hydrogen atom, an alkyl group, an alkenyl group or an acyl group, and R 12 and R 13 may be bonded together to form a ring; and R 1 and R 2 may be the same as or different from each other, wherein each of R 6 , R 7 , R 10 and R 11 represents —OM, wherein M represents a hydrogen atom, an alkali metal or a quaternary ammonium; each of R 8 and R 9 independently represents a hydrogen atom, a hydroxyl group, an alkyl group, an alkenyl group or NR 12 R 13 , wherein each of R 12 and R 13 independently represents a hydrogen atom, an alkyl group, an alkenyl group or an acyl group, and R 12 and R 13 may be bonded together to form a ring; and R 6 , R 7 , R 10 and R 11 may be the same as or different from each other, and wherein the following requirements are satisfied: 0.05≦A≦0.5 0.40 ≦B/A ≦0.75 wherein A represents a ratio of an intensity of phosphorus element to a total intensity of all elements detected in the toner by the fluorescent X-ray analysis, and B represents a ratio of an intensity of phosphorus element to a total intensity of all elements detected in a toner having been dispersed in an alcoholic solvent and followed by drying, by the fluorescent X-ray analysis.