US Patent 7438754 Cobalt-containing black pigment particulates

Disclosed is a black pigment having adequate degree of blackness and high electrical resistance at the same time. Specifically disclosed is a granular black pigment containing cobalt which is characterized in that it is composed of an oxide containing at least cobalt and the divalent cobalt content accounts for 40-70% of the total cobalt content. It is preferable that the total cobalt content in a whole particle is 60-80% by mass, and the divalent cobalt content in a whole particle is 20-50% by mass. It is also preferable that the primary particle diameter is 0.02-0.6 μm.