| 摘要 |
PROBLEM TO BE SOLVED: To suppress the chipping loss of toner images caused by top and bottom end blurring phenomena and to obtain an image of high quality by setting the difference in blurring tendency between the toner images formed with forward and backward rotating developer carriers, in a specific range. SOLUTION: The blurring tendency of the toner images of the respective developer carriers is represented by a value (x) defined by the equation: x= K.m.(V0-VB)}/ n0.G.(VB-VR)} and the difference (A-B) between the sum A of the value (x) in the forward rotating developer carrier 2 and the sum B of the value (x) in the backward rotating developer carrier 1 is prescribed to be within the range of -0.56-0.5. Where, K denotes the circumferential speed ratio of a corresponding developer carrier, (m) denotes the weight of developer passing through the developing region of the developer carrier and V0 denotes the non-image part potential of an electrostatic latent image. Then, VB denotes a developing bias applied to the corresponding developer carrier, VR denotes the image forming part potential of the electrostatic latent image and (n0) denotes the true density of carriers included in a two-component developer. Further, G denotes the interval between the developer carrier and an image carrier. |
