Toner is attracted to the electrostatic latent image on the EP (image) drum surface to convert it into a visible toner image. Developing takes place at the contact
between the EP (image) drum and the developing roller.
(1) As the toner supply roller rotates while rubbing on the developing roller, a friction charge is generated between the developing roller and the toner, allowing the
toner to be attracted to the developing roller. (The developing
roller surface is charges positive and the toner, negative.)
(2) The toner attracted to the developing roller is scraped off by the doctor blade, forming a thin coating of toner on the developing roller surface.
(3) Toner is attracted to the exposed part (low-potential part) of the EP (image) drum at the contact between the EP (image) drum and the developing roller,