GB549426A - Reciprocating facsimile apparatus - Google Patents

Abstract

549,426. Facsimile telegraphy. CREED & CO., Ltd. Sept. 19, 1941, No. 12061. Convention date, Nov. 15, 1940. [Class 40 (iii)] In a facsimile telegraph recorder in which a stylus reciprocates over a recording surface transversely of the movement of the surface, the stylus is arranged to be raised away from the surface during the return non-recording stroke. As shown, a continuous sheet of sensitized recording paper 11 travels from a roll 12 to a metallic platen 13 and then between feed rolls 14, 15 having intermeshing gears 17, 18 driven through worm gears 21, 22 and 24, 25 by a motor 26. While the sheet is being fed, a stylus 37 on a carriage 34 is moved across the sheet along guide rails 35 to record a line by means of a cord 32 which is wound up on a drum 30 driven through a friction cluch 29 by the shaft 23 of the gears 22, 24. The drum makes one rotation for every line of recording. At the end of each line, a deflecting arm 31 rotating with the drum 30 slips the cord 32 off the drum, and a cord 39 connected to a spring 43 causes the stylus carriage to fly back to the left in readiness for the recording of the next line. The stylus 37 is arranged to be lifted off the paper during the fly back of the carriage 34. For this purpose, the carriage 34 is hinged on a pivot 36 guided by the groove between the rails 45, and the cords 32, 39 are attached to lugs 33, 38 of the carrier 34 in such a position that the pull of the cord 32 during the recording traverse urges the stylus against the sheet 11, whereas the pull of the cord 39 during the fly back lifts the stylus off the sheet. The stylus is attached to the carriage by a leaf spring. Synchronizing is on the start stop principle. In one arrangement, Fig. 3, at about the same time as the cord 32 is slipped from the drum 30, a lug 48 on the drum is stopped by a latch 49 and a switch 67 is opened by a pin 71 on the drum. Then when a synchronizing signal is received a relay 68 is energized and closes the circuit of an electromagnet 51 which withdraws the latch 49 to start the line scanning operation. During this operation, the pin 71 leaves the switch 67 in the closed position short circuiting the relay 68. The relay 68 is connected to the mid-point of the output transformer 65 which supplies the stylus with recording signals from a class C pushpull amplifier 63, 63 connected by a transformer 62 to a signal inverter 61 receiving the signals from a line L. In a modification, a higher speed shaft, e.g. the shaft of the motor 26, from which both the drum 30 and the sheet feeding rolls are driven, is stopped by a marking signal causing an electromagnet to attract a latch, the latch is released by a non-marking signal causing deenergization of the latch magnet. The pivot of the latch is carried by a plate resiliently mounted between rubber pads.