| 摘要 |
PROBLEM TO BE SOLVED: To obtain a good image having satisfactory image density, in the case of carrying developer including toner and carrier by a developer carrier into a developing area facing an image carrier and developing an image. SOLUTION: As for the developing device which is constituted by fixing a magnet member 11a with plural magnetic poles inside the developer carrier 11 for carrying the developer 2 including the toner and the carrier into the developing area facing the image carrier 1, the volumetric packing ratio of the developer is controlled to be 5 to 40% in the developing area, and also, as for the peak value Gp of the vertical magnetic force by the magnetic pole N1 arranged on the magnet member so as to face the image carrier in the developing area and the means value GL of each minimum vertical magnetic force on both sides of the peak vertical magnetic force in the developing area, the following condition is satisfied; GL/GP>=0.5. |
