| 摘要 |
PURPOSE:To improve the reproducibility of density and reproducibility of thin line by driving at the same time a developing device in the up stream, with a high packing ratio of developer, and a developing device in the down stream, with low packing ratio of developer, in a developing range, developing at least twice a same electrostatic latent image. CONSTITUTION:At least two developing devices 1 and 2, which contain developers consisting of two components, toner and carrier, are provided at the side part of an electrostatic latent image carrier 100. Then the developer packing ratios of the developing area where developing sleeves 10, contained in developing devices 1 and 2, faces in opposition to the electrostatic latent image carrier 100, are set so that the upper stream developing device 1, with priority in the developing sequence, is made higher than the down stream developing device 2, and developing devices 1 and 2 are driven at the same time carrying out the developing of the same electrostatic image at least two times. Thus sufficient density of letter image can be secured and thin lines can be reproduced as it is. |
