Patent GB-427136-A (GB)
Title: Improved device for the reproduction of documents and the like
IPC: H04N1/032
Filed: 1934-02-20
Abstract: 427,136. Electric signalling systems. BRULIN, C. L. E., 20, Avenue Gabrielle, Montmorency, Seme-et-Oise, France. Feb. 20, 1934, No. 5614. Convention date, Jan. 25. [Class 40 (i)] A device for the reproduction of pictures, documents, &c., comprises a rotating plate on which is supported a disc carrying a track corresponding to the document to be reproduced, obtained by any suitable means such as by scanning with a light beam which subsequently falls on a photo-electric cell whereby current impulses in accordance with the variations of light and shade in the document are obtained and caused to produce mechanical vibrations which are recorded on the disc, in combination with a rotating cylinder supporting the sheet adapted to receive the reproduction, a pen which can be moved parallel to the axis of the cylinder and which is secured to an oscillating armature located in a magnetic field which is modulated according to the record found on the disc, and driving means for synchronously moving the rotating plate and the cylinder. The disc 35, which carries a track representing the picture &c., to be reproduced in the form of a wave track of constant frequency but variable amplitude according to the light and dark parts of the picture, is mounted on a rotatable plate 1 and is traversed by a pick-up of the type commonly used with gramophones, which therefore transmits a current of constant frequency but variable amplitude to the electromagnet 14. The armature of this electromagnet is mounted on a pivot 17 and carries at one end a recording pen 21, which is normally adapted to rest on the paper sheet carried by the drum 24 which is to receive the reproduction. The electromagnet and the recording device are carried by an adjustable pivoted arm 11 which has an extension 10 and a half nut 9 engaging a screw-threaded shaft 8, so that as the latter is rotated the recording-apparatus is carried longitudinally of the cylinder 24. The shaft 8 is rotated by an external handle and carries a gear 6 which drives the shaft carrying the plate 1 and a gear 30 which drives a gear 29 attached to the shaft carrying the cylinder 24, whereby synchronism of the disc 35 and of the cylinder 24 is ensured. In operation the pen traces out a helical path on the cylinder 24 and marks a waved line, the amplitude of the waves depending on the intensity of the current resulting in the pick-up from the track on the disc 35. A line of variable width is thus obtained, the wide parts corresponding to a dark part of the original picture and the thin parts to a light part. When not in use, the arm 11 is supported in the dotted line position, the pen being received in a cap 33 carried by a spring 34. Other means of driving the plate 1 and cylinder 24 may be used, when a device is provided for observing whether or not the parts are in synchronism ; this may comprise a fixed wire stretched parallel to the axis of the cylinder 24, which should remain parallel to the corresponding edge of the picture or to any line parallel thereto ; alternatively, a line may be drawn on the paper parallel to this axis. The speed of the plate 1 may be determined stroboscopically by dividing its edge into equal black and white alternate parts which are illuminated by a lamp supplied with alternating current.