| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of always forming an image having desired density corresponding to the secular change of toner density on a photoreceptor drum and transfer density to recording paper. SOLUTION: A toner density value at the surface part of the photoreceptor drum in an initial state is stored, and a toner density value by nonelectrified toner adhering to the surface of the photoreceptor drum which does not contribute to transferring to the recording paper is detected from a difference between the toner density value at the surface part at the time of maintenance and that in the initial state. Then, the toner density component by the non-electrified toner is subtracted from the toner density at each part of a gradation pattern developed on the photoreceptor drum detected at the time of maintenance so as to obtain the effective toner density value. Appropriate gradation correction characteristic in accordance with output characteristic at the time of maintenance is set based on the obtained effective toner density value. |
