Flash lamp fixing device

摘要

A flash lamp fixing with a simple structure, capable of obtaining an even distribution of high-level luminous energy over a large area on the surface of a paper sheet illuminated by a flash lamp. In the flash lamp fixing device, the half breadth L1 of the aperture of the reflector is set so as to satisfy the equation V/T>/=L1>/=V/T-L2/2, where V is the conveying speed of a paper sheet; T is the flash cycle of the flash lamp; L1 is the half breadth of the aperture of the reflector; and L2 is the length of an area in which fixing can be done by one flash of the flash lamp. Where theta 1 represents the included angle between a tangent which passes through one of aperture edges, being tangent to the flash lamp on the side of the aperture and the plane of the aperture; and theta 2 represents the included angle between a tangent which passes through the aperture edge, being tangent to a safety distance critical circle centered on the center of the flash lamp and a plane normal to the aperture plane, the tilt angles of the respective inclined face parts in relation to the plane normal to the aperture plane are set to be not less than theta 1 and not more than theta 2.