| 摘要 |
PURPOSE:To enable the easy and automatic calibration of a surface potential meter without using any special jigs, by generating a reference potential within an image region of a photosensitive body for the calibration of the surface potential meter. CONSTITUTION:A photosensitive drum 1 is charged by a corona charger 2 and then deelectrified by an image exposure light 3, and thereby a latent image is formed. Next, this latent image is transferred on recording paper 6 by a transfer charger 5 via a developer 4, while a toner remaining after transfer is collected by a cleaner 7. Meanwhile, a potential sensor 8 and a surface potential meter 9 read the dark and light potentials of the latent image and controls a variable high-voltage power source 11 and a development bias power source 12 so as to stabilize the quantity of a picture. On the other hand, a reference potential for calibrating the surface potential meter is formed on the photosensitive drum 1 by using an exposure light source 13 having a sufficient quantity of light for deelectrifying uniformly the surface of a photosensitive body on the photosensitive drum 1, and based on the reference potential, a false control of the surface potential meter 9 due to a drift is prevented. |
