Toner and toner binder
A toner comprising a toner binder and a colorant, composed of resin particles produced by causing an extension reaction and/or crosslinking reaction of a dispersion formed of a reactive group-containing prepolymer (α) contained in an aqueous medium with an extension agent and/or a crosslinking agent (β). The toner has a Wadell practical sphericity of 0.90 to 1.00 and is superior in fluidity, transferability, the storage stability under heat, low temperature fixing ability and hot offset resistance.