| 摘要 |
PURPOSE:To clean a sensor, which detects the density of a picture on an image carrier, and to enable exact picture density control without disturbing the picture on the image carrier with an air current by necessarily controlling the amount of air to be blown through an air pump driving means to the sensor. CONSTITUTION:A picture density detection sensor 15 is cleaned so as to detect the density of the picture of a photosensitive body 6 as the image carrier to be cleaned by the air current caused by an air pump 20. A pump room 20a to be freely stretched in the driving means of this pump 20 is controlled by a cam member 21 to be synchronously turned integrally with a timing roller 11a for paper feeding. Thus, during a period excepting for passing the picture of the photosensitive body 6 through the sensor 15, the sensor is satisfactorily cleaned by the strong air current. As a result, the picture density detection sensor is satisfactorily cleaned and the exact picture density control can be executed without disturbing the picture on the photosensitive body by the air current. |
