A toner having a negative triboelectric chargeability is constituted by at least a binder resin, a colorant, a wax and an organic metal compound. The toner is characterized in that: (a) the toner has an acid value of 5 - 35 mgKOH/g, (b) the binder resin comprises a vinyl polymer, (c) the binder resin in the toner contains a chloroform-insoluble content in an amount of 3 - 50 wt. %, (d) the toner contains a THF (tetrahydrofuran)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight range of 5,000 - 30,000 and at least one subpeak and/or shoulder in a molecular weight range of 2x10<5> - 15x10<5> and including 15 - 70 % of a component having molecular weights of 1x10<4> - 10x10<4>, and (e) the organic metal compound is an organic zirconium compound comprising a coordination or/and a bonding of zirconium and an aromatic compound as a ligand or/and an acid source selected from the group consisting of aromatic diols, aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids, and aromatic polycarboxylic acids.
Toner having negative triboelectric chargeability and image forming method