| 摘要 |
<p>PURPOSE:To detect a photographic density of an image after a development with a high accuracy by providing a shutter mechanism on the way of an optical path of a projection to a sensitive body and an electric charge extinguishing operation inhibiting means with respect to a sensitive section corresponding to a cut-off position to form a reference latent image. CONSTITUTION:On the way to an optical path of a projection to a sensitive drum 5 by an image forming device, a shutter 11 capable of freely changing a position and fixing in positions cutting off and not cutting off a projecting light B is disposed. When the shutter 11 is operated and the projecting light B is cut off, an electric charge on a drum 5 of a part corresponding to the operating position of the shutter 11 is not extinguished and remains, and a latent image LI' corresponding to the form of the shutter 11 is formed. The latent image LI' is disposed between the images passes through an eraser section 10 between the images composed of LEDs 10a and 10b, the LED 10b corresponding to the latent image LI' is put out and an electric charge putting out operation is inhibited. In this manner, a reference latent image LI is formed and an image density after a development can be detected with high accuracy.</p> |
