| 摘要 |
PURPOSE:To execute a black erasing exposure corresponding to a continuous variable power copying by only one light source by fixing an image forming lens and a black erasing exposing light source so as to be operated in one body, and also varying continuously its light irradiating range. CONSTITUTION:A black erasning exposing light source 10 is fixed to an optional part except a lens surface of an image forming lens 2, so as to be operated in one body with the lens 2. A projecting part 12 is provided on one edge of a light shielding member 11 so that a light irradiating direction from the light source 10 is limited to a photosensitive drum side. A grooved part 13 is formed by deriving a locus along which the projecting part 12 moves. The projecting part 12 is attached to the groove part 13 so as to be slidable. Also, a black erasing exposure control part 14 for controlling an advancing direction of an edge part L of a light from the light source 10 is formed on the light shielding member 11 so as to be positioned between the light source 10 and the photosensitive body surface. In case when the lens 2 moves in accordance with the copying magnification, and an exposure range of an original image on the photosensitive body is narrowed, a relative position of the lens 2 and the light source 10 is not varied, but the projecting part 12 moves along the grooved part 13, therefore, the light shielding member 11 and the control part 14 also move following it, and in the end, the black erasing exposure range is expanded and the black erasion is executed to a desired area. |
