| 摘要 |
PURPOSE:To obtain a proper image even with variable power by providing a setting means which sets the density of a formed image during image formation on the basis of data on the density and magnification of an original in a specified area. CONSTITUTION:Coordinate data and variable power data are inputted and a prescan for AE value setting is made; and original density is read by a CCD line sensor 2 and an analog signal is converted by a A/D converting circuit 3 into a digital signal with a level corresponding to the density. Then, histograms are formed on the basis of the brightest value and darkest value among digital data on original density of respective lines of an input specified area and an exposure voltage is determined with a coefficient value based upon the maximum value of the histogram of the brightest value and the variable magnification data. Then, counter values for determining on-off states of blank counters n1-n3 and blank lamps L0-Ln are set according to the specified area and a counter value is determined on the basis of the specified area data and variable power data. Thus, an invariably proper image is obtained even with the power variation of the specified area. |
