TONER AND IMAGE FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a toner excellent in efficiency of transfer of a toner image, ensuring little untransferred residue of the toner, not causing fusion to the top of an image carrier and giving a high grade image even by printing repeated many times. SOLUTION: This toner contains toner particles contg. a colorant dispersed in a bonding resin and inorg. fine powder. The shape factory SF-1 of this toner measured with an image analyzing device is >110 to 180, the shape factory SF-2 is >110 to 140 and the ratio B/A of value B given by subtracting 100 from the SF-2 to value A given by subtracting 100 from the SF-1 is <=1.0. The relation between the specific surface area Sb(m<2> /cm<3> ) of this toner per unit volume measured by the BET method and the specific surface area St(m<2> /cm<3> ) per unit volume calculated from the weight average particle diameter of this toner assumed to be spheres satisfies the conditions 3.0<=Sb/St<=7.0 and Sb>=St×1.5+1.5.