Optisches Abtastsystem fuer Faksimilegeraete

摘要

809,483. Copying-telegraph transmitters. CREED & CO. Ltd. June 15, 1956 [June 20, 1955], No. 18663/56. Class 40 (3). In a facsimile transmitting apparatus in which the matter to be transmitted is on the inside surface of a blank wrapped in cylindrical shape and is scanned by a rotating mirror mounted within a casing forming a light shield for the mirror, the shield is provided with an opening through which the scanning beam passes to the inner surface of the blank and through which the diffusely reflected light from the blank passes to the mirror and along a path including that of the incoming or incident scanning beam to a short focus collector lens which concentrates on to the light-sensitive element of a photo-electric device, the diffusely reflected light impinging on and reflected by the rotating mirror. The beam b from a tungsten light source 40 passes via lens 48, stop 49, aperture 50 and a further lens 52 to a mirror 60 from which it is reflected to a mirror 28 mounted in a shielding housing 24 which is formed with a flange 25 and the scanning aperture 30, and is carried by a shaft 26 rotated at scanning speed. The blank t is mounted on a transparent cylinder 10, preferably of Lucite, with a wrapper 18 which may pass around a tensioning roller 20. Each end of the cylinder 10 has a groove 10a associated with supporting rollers 12 which, together with the roller 20 are mounted in end arms 141 of a frame 14 which slides on a shaft 17 and which, during the scanning operation, is traversed to the right against a spring 16 operating to return the carriage 14 to its normal left-hand position at the end of the message. The mirror 28 is set at an angle less than 45 degrees, e.g. 34 degrees, to the direction of the incident beam, and the aperture 30 is sufficiently large to pass the cone b1 of reflected light delimited by the opening at the end of the shield 24. The reflected cone b1, which embraces the incident beam b, is focused by the double Fresnel lens 62 on to the photo-sensitive cathode 64 of a multipler cell 66. The mirror reflection from the surface of the blank is diverted to the left of the opening 30, and the reflections from the inner surface of the transparent drum 10 are deflected by the mirror shield together with its flange 25 towards the left, i.e. in the direction opposite to that of the diffusely reflected cone b1.