| 摘要 |
PURPOSE:To keep high picture quality stably at all times by preventing the degradation of the picture quality caused by the change in environment (temperature and humidity), deterioration in a density detection sensor and surface deterioration of a photosensitive body, etc., in the digital recorder of the electrophotographic system such as a laser printer. CONSTITUTION:The recorder has a feedback system to a picture signal density processing system, high density processing data and low density processing data as a test pattern given from a control circuit 30 are emitted from a laser unit 1 alternately onto the photosensing body 2 to form an electrostatic latent image. The electrostatic latent image is visualized by toner of a developer 3 and the density on the photosensitive body 2 to be visualized is detected by sensor sections 4, 5. Then a maximum value circuit 7 and mean value circuits 8, 9 are used to obtain a (maximum value)/b(mean value) (or b/a) based on the maximum value (a) and the mean value (b) of the level detected and amplified by an amplifier 6 and the control circuit 30 modulates the density of the picture data being a processing object through, e.g. an LUT (lookup table) 12. |
