| 摘要 |
PURPOSE:To evade color mixture even when recording is repeated and obtain excellent polychromatic print stably by making the toner surface of a preliminary developing means except a final developing stage rugged, and increasing sticking force to a photosensitive body. CONSTITUTION:An electrostatic charger, the 1st exposing part and developing part, a recharger, and the 2nd exposing part and developing part are arrayed successively at the outer periphery of the photosensitive body; and the same magnetic material is used for the carriers used in and the 1st and the 2nd developing parts the 1st and the 2nd toner particles 24b and 34b are made of nonmagnetic insulators having the same mean grain size, but the surface of the 1st toner 24b is made finely rugged. Therefore, electrostatic force, mechanical frictional force, etc., caused by an uneven microelectric field produced at the periphery of the toner 24b are applier intensely and the sticking force to the photosensitive body 1 becomes larger; and a toner image which is formed firstly is not separated from a photosensitive layer 11a and no different color toner enters the developing device, so excellent polychromatic recording is carried out without color mixture. |
