Patent GB-347250-A (GB)
Title: Improvements in or relating to electric recorders
IPC: H04L15/30
Filed: 1930-01-20
Abstract: 347,250. Electrostatic meters. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Marconi House, Strand, London.- (Assignees of Hansell, C. W. ; Port Jefferson, Long Island, New York, U.S.A.) Jan. 20, 1930, No. 2016. Convention date, Jan. 19, 1929. [Class 37.] A recorder for high-speed telegraphy or general oscillograph work comprises a fine fluid jet impinging upon a record sheet and deflected electrostatically by the signal energy, means being provided for causing a potential difference between the stream and record sheet to prevent splashing. The jet may comprise ink to which soap or wax has been added, or it may comprise a hot conductive gas or vapour stream, or a jet of flame. The record may be a continuous wavy one or it may be broken into dots and dashes &c. In order to dry the record quickly when ink is used the platen is warmed. The speed of recording may be varied by superposing an auxiliary current supply upon the signal current. To prevent smudging of the record should the tape stop, baffling devices for the jet are provided. These baffles also permit removal and replacement of the glass nozzle, means being provided for draining the liquid. Jet-baffling means may be automatically positioned on stoppage of the tape or record sheet. As shown, Fig. 1, a jet 4 impinges on the record tape 30 behind which a platen 32 is connected to earth or to the low potential side of the anode source 36, recording potentials being received on line 8 through a pushpull amplifier 20. The jet nozzle and anode source are connected to the mid-point of output impedances 22, 24 and control bias is effected through lead 26 so that one or other of the electrodes 6, 16 is excited. Several stages of amplification may be provided. The valves can be biased to cut off anode current when signal current is not flowing. Constructionally, Fig. 2, the electrodes 6, 16 are adjustably mounted, and the jet 4 flows from a nozzle 54 having a universal mounting 58 connected with a reservoir 82 under pressure up to 150 pounds. The jet passes through an opening 64 in a draining trough 62, the opening being closed by a baffle-plate 66 when the apparatus is not energized. The baffle-plate 66, Fig. 5, is adjustably secured to an armature 72 of an electromagnet 74 in the mains circuit 114, and is slotted at 104 to coincide with the trough opening 64. In the position shown, dots and dashes are recorded on the tape 301, but when the baffle portion 102 is clear of the opening 64, a wavy record is made as shown on tape 30. The upward movement of the baffle-plate is regulated by the adjustment 128. When the end of the tape occurs, the tape reel 34 and contact spring 110 short-circuit the electromagnet 74. The platen heater coil 124 is energized from the mains through a variable resistance 122. In order to slow up the working speed, an auxiliary source of alternating current 130, Fig. 10, having a frequency much higher than the frequency of the signalling current is superposed thereon, the amplitude of the superposed current being regulated by resistances 138. High resistances 140 are inserted in the nozzle circuit to prevent shocks to the operator. Specification 337,937, [Class 37, Electricity, Measuring &c.], is referred to.