| 摘要 |
PURPOSE:To disuse a large scale memory, to compensate the influence of a toner image and to realize proper exposure by correcting the influence on exposure by a toner image with the specified correction of a specified color as reference and in accordance with the gradation data on all the images exposed till a prestage. CONSTITUTION:A signal is inputted in an arithmetic part 106 from a reference light quantity setting part 116 to which a CPU 114 is connected. Information on the electrostatic charge characteristic of a photoreceptor drum 72 is inputted from the CPU 114 to set the exposure being the reference. A reference light quantity is outputted to the arithmetic part 106 synchronizing with a signal from an A/D converter 120, that is, the start of the exposure based on the gradation data. After considering an exposure correction value in the arithmetic part 106, a current value is controlled by a current control unit 112 through a D/A converter 110. As for the characteristic chart to obtain the exposure correction value for the gradation data, only the chart of a color Y is stored in such a case and those of other colors are approximately arithmetically obtained by an easy linear expression based on the characteristic chart of the color Y, thereby reducing the memory. |
