| 摘要 |
PURPOSE:To easily select desired image density by providing a switch for selecting a desired gamma curve from a group of gamma curves on an operational panel. CONSTITUTION:The density of an imaging pattern 10 is detected by a reflective optical sensor 13 which is composed of an emitting device 11 and a light receiving device 12, that are arranged in an opposed way, and which is arranged in the proximity of a photosensitive drum 1, and image density is controlled by the output. In this case, two kinds of gamma curve groups are determined, and a desired gamma curve is selected from respective gamma curve groups by an operation switch 14 which is provided on an operation panel, and which is composed of notch and switch and so on, and the image density is controlled according to a gamma curve characteristic thus selected. Namely, when toner concentration(T.C.) is to be changed, by changing developing potential of the imaging pattern 10 while output ratio of the optical sensor 13 is put on a good accuracy point, the T.C. is changed into an aimed level, in such a way that the toner adhesion on the pattern is unchanged while the aimed toner concentration is changed. |
