| 摘要 |
PURPOSE:To stably form an image reproducing the original gradation with fidelity by providing the title device with an image carrier and respective means for electrostatically charging, forming a latent image, developing, detecting image density, and controlling potential difference. CONSTITUTION:A developing device 3 is disposed above a photosensitive body 1 revolving in the direction of an arrow, to be positioned in the downstream and at a right angle with respect to an electrostatical charger 2, and an image is exposed midway between between the charger 2 and the device 3, with laser beams. An image density detecting latent image formed on the photosensitive body 1 is developed by the developing device 3, and becomes a visible image, whose image density is detected by an image density detector 12 in the downstream. Based on the result of the detection, a mainbody controller TC adjusts controllers GSC and VBC to control the potential difference between the electrostatically charged potential of the photosensitive body 1 and the developing bias potential of the developing device 2. Thus, even when the carrier's electrostatically charged potential through the same electrostatically charging operation fluctuates, due to the repeated use of the image carrier 1 and environmental changes is temperature, etc., the potential difference is always retained at a specific value, therefore, the gradation of the image is always maintained favorably and desirably. |
