PURPOSE:To eliminate damage due to mutual interference between mutually opposite light source light emission parts by providing a light shield means composed of a light shield plate and a control means which controls the driving of a light shield plate. CONSTITUTION:Mutually opposite light sources 1 and 1 are arranged while moved by the radius length of reflecting mirrors 2 and 2 so as to suppress the interference between the light sources 1 and 1. Sensors 9a and 9b of a control means monitor whether or not a material 6 to be exposed which is fitted to an exposure table where conveying means 5 and 5 are assembled and fed has an upper/lower overlap part in an exposure irradiation range at two systems of conveying means 5 and 5. When there is not the material 6 to be exposed between the sensors 9a and 9b and a blank is formed, detection signals of the sensors 9a and 9b are sent to the control means and rotary solenoids 8 and 8 coupled with shield plates 7 and 7, etc., are driven. Then, the light shield plates 7 and 7 which are normally positioned in parallel to irradiated light to transmit the light are rotated to positions perpendicular to the irradiated light to cut off the light, thereby preventing the upper and lower light sources 1 and 1 to interfere directly with each other.
展开▼
