| 摘要 |
PURPOSE:To detect easily and accurately abnormaity of a photosensitive layer by deciding on abnormality of a measured potential at some point by comparing it with the mean value of measured values at several points right before it when scanning on the entire surface of a photosensitive body and measuring the surface potential. CONSTITUTION:A corona impressed voltage corresponding to a specific electrification potential is obtained before the primary measurement, and the high-voltage power source of an electrifier 2 is controlled automatically to make electrification constant. While the photosensitive body 1 is rotated, a probe 3 for potential detection is scanned from one end to the other to measure the surface potential. In this case, surface-potential data 5-10 at precedent points are stored invariably and their mean value is calculated and compared with the current measured value to obtain variation. When the difference between the mean value and measured value exceeds a specific reference value, a decision on a abnormal part is made. If the measured value at a point A is judged to be abnormal by this method, variation levels on (x) and (y) coordinates are recorded and the number of defects and their positions are displayed lastly. Thus, the abnormality detection is performed easily and accurately. |
