Patent ID: 8563206

Claim:
A negatively chargeable developer, comprising: negatively chargeable toner mother particles including at least binding resin and colorant; a first external additive having positive chargeability that is externally added to a surface of the toner mother particles, the first external additive including polymethyl methacrylate added in a range from approximately 0.4 parts by weight to approximately 0.8 parts by weight inclusive per 100 parts by weight of the toner mother particles; and a second external additive that is externally added to the surface of the toner mother particles, the second external additive being a member selected from the group consisting of silica, oxidized titanium and mixtures thereof and being added in a range from approximately 2.2 parts by weight to approximately 5.0 parts by weight inclusive per 100 parts by weight of the toner mother particles.