| 摘要 |
PURPOSE:To obtain prints of good quality by a simple device over a wide original density range by providing a manual and an automatic density adjusting means and setting at least two stages of manual density level when the manual density adjusting means is selected. CONSTITUTION:Reflected light from an original is inputted from an optical fiber 16 fitted to a copying machine which is not shown in a figure and converted by a photodiode 17 photoelectrically and the maximum value is detected from the texture of the original by a peak holding circuit 21, A/D- converted 22, and inputted to a circuit 18. When an automatic density adjustment mode is set with a key 23, a CPU 19 controls a developing bias power source 23 through an output interface 20 with the output of the A/D converter 22 to turn on a display board 5. Further, when a manual density adjusting key 1 or 2 is operated to 'thick' or 'thin', a developing bias is adjusted according to the number of times of the operation to make, for example, a seven-stage display on the display board 3. Thus, a copy of good quality is taken by the simple device corresponding to wide-range density. |
