| 摘要 |
PURPOSE:To reproduce a picture without generating a ground fog by deriving exactly a peak level density of a low density side, and a histogram density width by quantizing them minutely. CONSTITUTION:When an original 1 is being fed, a picture of the original 1 is discriminated by a photoelectric converting element 16 and a signal processing part 17. That is to say, first of all, a light quantity signal is converted to an electric picture signal Se by the photoelectric converting element 16, sampled by a sampling circuit 171, and brought to digital conversion by an A/D converter 172. As for this digitized picture signal Se, in a CPU173, a preparation of a density histogram and a picture discrimination are executed by the aid of memories 174, 175, and a picture discriminating signal Sb is inputted to a process control part 18. The process control part 18 gives an electrostatic charge current based on a result of discrimination, and from a light source 12a, a light of a prescribed intensity is irradiated to the original. In this regard, the electrostatic charge condition and the developing condition are set by an electrostatic charge current value, and a change of a developing bias voltage value, respectively. |
