| 摘要 |
PURPOSE:To satisfy the different requirements for the image quality of black and white copying and full-color copying and to obtain good images by increasing the electric resistance value of the carrier of a black developer larger than the electric resistance value of the carriers of respective color developers. CONSTITUTION:The electrostatic latent image formed on a photosensitive body in accordance with the image having a colored solid part 13a and a black line part 13b has the increased electric field intensity in the part corresponding to the edge part of the solid part 13a and the line part 13b. Toners of nearly uniform amt. stick to the respective parts of the electrostatic latent image as the counter electrode effect at the time of development is large, if the electrostatic latent image corresponding to the solid part 13a is developed in this state by the color developers having the electric resistance value of the carrier smaller than the electric resistance value of the black developer. The transferred image having no density unequalness is thus obtd. The toners of the sufficient amt. stock to the electrostatic latent image as the counter electrode effect at the time of development is small, if the electrostatic latent image corresponding to the line part 13b is developed by the black developer having the large electric resistance value of the carrier. The sharp image is thus obtd. |
