| 摘要 |
PURPOSE:To make a good copy excellent in the reproduction of half tone, even in a widespread contract change on an original by controlling the density of a high density component (HD component) based on the output of an automatic exposure (AD) sensor finished to read the distributions of various densities on the original. CONSTITUTION:The AE sensor 103 scans the original 101 to read its, contrast distribution. An HD density calculating circuit 10 inputting the output of the AE sensor 103 separates an input signal to a low area component and a high area component, the low and high area components are integrated respectively after an absolute value is taken, and the integrated value of the low area component is subtracted from the integrated value of the high area component and outputted. A high voltage control circuit 106 is controlled by the output of the HD density calculating circuit 105, obtained in this way and the electrostatic charging voltage of a photosensitive body is made high on a high contrast original and made low on a low contrast original, so that the density of the HD component corresponding to the distributions of various densities on an input original can be obtained. |
