| 摘要 |
PROBLEM TO BE SOLVED: To form the uniform developer layer on a developing roll surface, while to reducing deterioration of the developer in such a manner, and to stably obtain an excellent image being free from the image defect, in the case of making an electrostatic latent image on the image carrier possible to be visualized, with use of the two component developer containing toner and carriers. SOLUTION: This device is allowed to arrange the developing roll 12 provided with a magnetic recording layer 12b and the conductive layer 12a so as to closely oppose the image carrier 1, and to magnetically stick N poles and S poles on this magnetic recording layer 12b with a fine clearance. The device is allowed to equip the layer forming roll 13 forming the developer layer on the developing roll 12, on the upstream side of a position opposite to the image carrier 1 in the rotary direction of the developing roll 12. The layer forming roll 13, provided with the magnetic roll 13b, is rotary driven while alternately furnished with respective N pole and S pole along the periphery, while the revolutions W (rps) of this magnetic roll 13b and the number of poles P, and the surface traveling linear velocity Vd (mm/s) of the developing roll 12 are in the relation that satisfies the next numerical formula, Vd/(P.W)<=2. |
