PHOTOSENSITIVE CHARACTERISTIC MEASURING DEVICE FOR PHOTOSENSITIVE DRUM

PURPOSE:To accurately measure photosensitive characteristic in a short time by providing a potential sensor which measures the potential of the surface of a photosensitive drum in an axial direction on a downstream side in the rotating direction of the photosensitive drum as compared with an exposing position by a light source and a destaticizing means which destaticizes the surface of the photosensitive drum almost all over the area in the axial direction on the downstream side of the sensor. CONSTITUTION:In a state where a light source 32 is not actuated and an electrostatic charging device 31 and the destaticizing device 60 are actuated, the photosensitive drum 91 is rotated in a specified direction by a photosensitive drum rotating means 80. The sensor 26 measures the surface potential of the drum 91 which is electrostatically charged by the device 31 over one round of the drum 91. The surface of the drum 91 is destaticized by the device 60 after measuring the surface potential thereof. Next, the surface potential of the photosensitive drum at the specified position in the axial direction of the drum 91 is measured by the sensor 26 in a state where the light source 32 is actuated. Based on the measured results, the photosensitive characteristic of the drum 91 is decided. Thus, the photosensitive characteristic of the drum 91 is extremely accurately measured in a short time.