| 摘要 |
PURPOSE:To prevent a developer from scattering and falling even if a casing is deformed owing to a temperature rise by making the gap between a developing sleeve and the casing of the developing device wider at the center part than at the vicinity of both plates of the casing. CONSTITUTION:A projection part 11C is provided on the internal wall bottom part of the casing 11 of a developing device main body and the gap l4 of the center part is set as the distance between the tip of the projection and developing roller 13 to a distance wider than the gaps l3 in the vicinity of both side plate parts 11B of the casing 11. For example, the gap l3 of an internal wall part 11D is 1.6-2.0 mm and the gap l4 of the inner wall 11E in the vicinity of the center part is 2.4-2.8 mm. Consequently, even if the temperature in the casing 11 rises up to the room temperature plus 55 deg.C, i.e. maximum 80 deg.C and the casing 11 is lent, the gap does not become narrow because the gap l4 is set wide, so that the developer can be prevented from leaking and falling from the machine. |
