| 摘要 |
PROBLEM TO BE SOLVED: To provide an output image of the desired gradation by selecting a comparative dot image of the desired area ratio, and controlling the image forming condition based on the area ratio of the selected comparative dot image and the reference dot image by a sensor. SOLUTION: A solid reference image is formed on a photosensitive body 1 at the reference surface potential and the reference developing bias potential, and the toner adhesion is detected to set the developing bias potential of the desired adhesion. The comparative dot image of the specified area ratio is formed on the photosensitive body 1 through an operation panel 20 in the set developing bias potential and the standard surface potential, and the area ratio is detected based on the output of an image sensor 10. Then, the reference dot image is formed to detect the area ratio. Difference in the area ratio between the comparative dot image and the reference dot image is obtained, a look-up table which is stored in a memory 14 in advance is referred to, and the surface potential is set based on the difference in the area ratio so that the area ratio of the comparative dot image is same as that of the reference dot image. |
