| 摘要 |
PROBLEM TO BE SOLVED: To produce a developing device easily and inexpensively by forming a cylindrical developing roll by means of mutually connecting both ends of a stainless steel plate of uniform thickness together. SOLUTION: A developing roll 20 is formed of an electric resistance welded pipe 31 made by rounding a stainless steel made band plate 30 in its width direction and welding them together. In other words, the electric resistance welded pipe 31 is formed by rounding the band plate 30, which is coiled in a reel shape, in its width direction as it is drawn out and connecting both side ends facing each other by welding after which the same welded pipe 31 is cut a specific length. In rounding the band plate 30, a die body, through which the band plate 30 is inserted, is used and the band plate 30 drawn out from the die body in a cylindrical shape is immediately welded so that the electric resistance welded pipe 31 is formed in the complete roundness. The developing roll 20 cut from seam welded pipe 31 is ground on its outside circumferential surface by a centerless grinder and the outside circumferential surface is finished to a specific roughness. |
