| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the scraping of a developing material by a developing roll on the downstream side in the rotating direction of a photoreceptor and to obtain an image of good quality having no image deficient by setting the image formation conditions of a developing bias, etc., on the basis of the development partial charge rate of developing rolls. SOLUTION: The photoreceptor 1 is rotated to charge its surface electrostatically and an exposure device is driven to form a 1st reference surface. In the developing device 21, only the first developing roll 53 is made ready for development. The first reference image on the photoreceptor 1 is developed only by the first developing roll 53 to obtain a first visible image, a sensor read its image density, and a control unit finds the first toner sticking amount and drives the exposure device to form first and second reference images. A second visible image is formed by developing the second reference latent image by using first and second developing rolls 53 and 55, and the sensor reads the image density to find the second toner sticking amount. The development partial charge rate of the first and second developing rolls 53 and 55 is found from the difference between the first and second toner sticking amounts to change the image formation conditions. |
