| 摘要 |
PURPOSE:To execute maintenance at a correct timing and to prolong life, by detecting the period for maintenance, announcing the same and changing either of an image part and a nonimage part substantially from the normal density. CONSTITUTION:A controller 18 controls the electrification potential of a photosensitive belt 1 by controlling an electrifying device 5. Upon attaining of the period for maintenance, the controller decreases the electrification potential from a normal value to make the image density of the record considerably lower than the normal density to force the operator to recognize the same; therefore, the operator is able to make maintenance at the correct period. The critical state of the device and the decreased life thereof are thus prevented. |
