Patent ID: 7022449
Filing Date: 2006-04-04
Classification: G03G

Abstract:
1. A black toner comprising toner particles containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particle has weight-average particle diameter of 3.5 to 8.0 μm; total value of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 μm or more is 0.915 to 0.960; loss tangent tan δ (10  where the loss tangent tan δ is represented by ∈″/∈′ where ∈″ denotes dielectric loss factor and ∈′ denotes dielectric constant, and tan δ (10 a ratio of tan δ (10  where tan δ (10 wherein the toner has molecular weight distribution whose main peak is in a range of 3,000 to 40,000 in gel permeation chromatography (GPC) of tetrahydrofuran (THF) extraction, and has Mw/Mn of 70 or more where Mw denotes weight-average molecular weight and Mn denotes number-average molecular weight.