| 摘要 |
PURPOSE:To reduce unnecessary stress applied to a magnetic developer in a developer conveyance area and prolong the life of the developer by arranging a magnetic plate fixedly in the space part formed between a nonmagnetic sleeve and a magnet roller. CONSTITUTION:The developing device is so constituted that an iron plate having, for example, a 1mm. thickness is made into a magnetic plate and arranged in the space part between the nonmagnetic sleeve 22 and magnet roller 23 which correspond to the position where the surface of the nonmagnetic sleeve 22 contacts a scraper 5. In this constitution, about 800 gauss magnetic force is measured at a part I on the outer circumferential surface of the nonmagnetic sleeve 22 where said magnetic plate 24 exerts no influence, but 250 gauss is obtained when the nonmagnetic sleeve 22 is in the area and reduced to about one third. Thus, the unnecessary stress is reduced, and the life of the developer is prolonged. |
