| 摘要 |
PROBLEM TO BE SOLVED: To make an image property so as possible to be satisfactorily stabilized, even when lowering of the developing property of a developer is occurring in some degree by making the image passing time over a groove part and one cycle of an AC electric field possible to specify a specific relation. SOLUTION: This device is allowed to form the groove part 5a on a surface of a developing roller 5 along the shaft direction thereof. Then, a great number of these groove parts 5a are formed over the peripheral direction of the developing roller 5. Moreover, a sectional plane of the groove part 5a on the developing roller 5 is formed in a V-shape, or the sectional plane in the recessed shape. At this time, assuming traveling speed of the surface on the image carrier as Vp, the traveling speed of developer feeding means as Vs, the width of the groove part 5a as L, the time for image to pass through groove part 5a as T1=L/(Vs-Vp), and one cycle of AC electric field as T2, the next relational expression is satisfied, 2<=T1/T2<=20. Thus, by adopting the developing roller 5 that the groove part 5a is formed thereon, even when the developer property is lowered in some degree as a result of outputting the number of image sheets, the developer feeding quantity on the developing roller 5 is stabilized without the change. |
