| 摘要 |
PURPOSE:To obtain a high-definition image by providing a spring plate material, and a chip part provided on this spring plate material so as to abut on the surface of a developing roller at least over an effective developing width, on a developer thin layer forming means. CONSTITUTION:A blade 16 as the developer thin layer forming means for forming a toner thin layer on the surface of the developing roller 12 is always energized by plural compressing springs 22 through the use of a rotary shaft 21 as a fulcrum, so as to press the surface of the developing roller 12 with proper force by the top end part (chip 162) of the blade 16. The spring constant of these compressing springs 22 is lower than that of the blade 16 (a thin plate spring material 161), so that even if the chip 162 of the blade 16 is worn, its pressurizing force has hardly influence. Thus, an uniform developer thin layer can be formed on the developing roller, and simultaneously, the wear of the chip part can be minimized, as well. Therefore, the degradation of image quality such as density irregularities, reduction in a density, the increasing of fogging on a sheet can be prevented, and the high-definition image is obtained. |
