| 摘要 |
PURPOSE:To detect the toner density of a toner image exactly even when unevenness in development occurs, by providing a detector with a smoothing circuit for smoothing development output of the detector for receiving and detecting the light reflected from the toner image. CONSTITUTION:A detector 10 for detecting the density of the toner image of a reference target 3 formed on a photoreceptor 6 is installed above a developing device 7. The detector 10 is a reflective sensor consisting of a light emitting element 10a, such as a light emitting diode, and a photodetector 10b, such as a phototransistor, and it is arranged in the position corresponding to the toner image A of a reference target 3, and it can detect the density of the toner image. The output detected with the photodetector 10b enters a smoothing circuit 30 consisting of a capacitor circuit, the output detected is freed from a fluctuating component and becomes almost constant even if any unevenness occurs in development, resulting in exactly detecting the image density, thus permitting the toner density to be exactly detected even if any uneven development takes place. |
