| 摘要 |
PURPOSE: To accurately control the density and color tone of a formed image by surely returning or retracting a developer from a developing sleeve to a supplying sleeve. CONSTITUTION: Magnetic poles N4 and S4 are formed on the magnet 42 of a developing roller 36 and the magnet of a supplying roller 46 which face a returning region D2 where the developer is returned from the developing sleeve 43 of a developing unit to the supplying sleeve 48, respectively and the magnetic force of the magnetic pole N4 is made small not to form a magnetic field with a magnetic pole except the magnetic pole S4 formed on the magnet 47 of the supplying roller 46. |
