Image forming apparatus comprising developing means provided with a black toner with specific sphericity , use of this black toner in an imaging process and toner kit

摘要

An image forming apparatus has an electrostatic latent image bearing member (1), a developing means (4) for forming a toner image on the electrostatic latent image bearing member (1), an intermediate transfer member (5) for holding the toner image, and a transfer means (7) for transferring the toner image to a transfer medium (6). The developing means (4) uses a toner. The toner is a black toner having at least i) black toner particles formed of a binder resin with a colorant dispersed therein and ii) an inorganic fine powder. The black toner has the value of shape factor SF-1 of 110 < SF-1 ≤ 180, the value of shape factor SF-2 of 110 < SF-2 ≤ 140, and the value of ratio B/A of 1.0 or less which is the ratio of a value B obtained by subtracting 100 from the value of SF-2 to a value A obtained by subtracting 100 from the value of SF-1.