| 摘要 |
PURPOSE:To arbitrarily select and set the installed position of a density sensor, and to improve the degree of freedom of a layout of the whole device, by constituting and placing the density sensor so as to go into and out of the development density detecting area of a density pattern latent image in accordance with the ratio of a variable power. CONSTITUTION:A density sensor is installed so that it goes into the development density detecting area of a density pattern latent image in the enlargement side variable power of an image magnification (m) or above, and also, does not go into the development density detecting area in the reduction side variable power of the image magnification (m) or below. Accordingly, the density sensor is installed so as to be provided opposingly to a dark potential part being a non-exposure area, and the potential of the dark potential part is detected by the density sensor thereby. That is to say, in case of the former, the development density of the density pattern latent image is detected by the density sensor, and in case of the latter, the potential of the dark potential part is detected by the density sensor. In such a manner, it is prevented that the set position of the density sensor is limited to a specific position. |
