| 摘要 |
PURPOSE:To obtain an image forming device capable of arbitrarily changing the control of image density b providing a density control means which arbitrarily changes relations between an original density detection signal and an image forming condition. CONSTITUTION:A luminous flux 31 from a lamp 18 is reflected on an original 28 and is received by a photodetector 33 through an optical fiber 32. The photodetector 33 is connected to a peak holding circuit 45, and a photocurrent corresponding to the quantity of light transmitted to the photodetector 33 is converted to a voltage by the peak holding circuit 45, and the peak is held to detect the ground density of the original. A CPU 46 controls a developing bias power source 47 in accordance with an output voltage VDE of the peak holding circuit 45 and applies a developing bias voltage VB corresponding to this output voltage to a developing sleeve 14. Thus, the control of image density is arbitrarily changed to obtain desired copies. |
