GB1072260A - Improvements in or relating to page recording methods for hell characters, and apparatus therefor - Google Patents

Abstract

1,072,260. Selective printing. R. HELL. Aug. 4, 1964 [July 20, 1963], No. 30602/64. Heading B6F. [Also in Division G4] Wire element printers; electrical signal input arrangements; inkless and electrographic printing.-In a telegraph receiver the characters received in the form of telegraphy pulse frequencies are continuously and successively recorded in the form of latent images on a circulating endless tape 6 serving as an intermediate recording carrier and are stored for at least a length of one line, the individual stored lines, each in its entirety, being subsequently transferred one below another on to a continuously advanced paper 12 by a transport roller 10 co-operating with an idler roller 11. After a line has been transferred the recorded latent images are erased from the tape by a rotary brush 39. In operation, pulse frequency signals are received from a transmitter (not shown) which makes use of a perforated tape carrying the characters in a six-bit code, said tape being scanned by photo-electric means and converted by an electronic converter into said pulse frequencies. Before commencement of recording the transmitter sends a starting signal of 1 second's duration which is received in a line 54, amplified in an amplifier 55 and demodulated in a rectifier 56. The signal then charges a capacitor 57 and brings up relay E and the slow-release relay F. The former energizes electromagnets 47, 53 . . . The latter operates R which locks and energizes motors 1, 27, 23, 41 and an inframed heater 32. Motors 1 and 23 rotate their respective shafts, whereby the projections 46, 52 are arrested by pawls 43, 49 so that shafts 34 and 24 may be synchronized for line length and correct alignment of the first recorded character on the line respectively. For line length alignment the wheel 3 has a circumference corresponding to a line and the shaft 34 associated therewith is provided with a cam 35, provided with a permanent magnet 36 and co-operating with a pickup 37 to operate a gate 30 by induction of a voltage pulse, when the first recorded latent image arrives in appropriate first character position opposite the paper 12. When the starting signal terminates the relay E releases, but F remains held by the telegraphy pulses and holds R so that the received telegraph signals open gate 14 to apply high voltage pulses from source 15 through connector switch 19 to seven electrodes 16 of an electrode assembly 17, to form latent images of characters on the continuously rotated tape 6, which has a layer of synthetic plastic facing the electrodes, the opposite side of the tape having a metallic line to earth, the tape via guide roller 4 and friction contact 8. The latent images are dusted by a xerographic dust by a magnetic brush 28 co-operating with an alignment roller 26. The dust may consist of fine iron filings and synthetic resin. When a complete line of latent and dusted images arrives opposite the paper 12 the previously synchronized cam 35 actuates the pick-up 37 opening the gate 30 which sends a pulse of high voltage to the transport roller, whereby the entire line of latent images is transferred simultaneously to the paper the transferred latent images being subsequently fused by the heat generated by the infra-red heater 32. The recorded latent images are then removed by a brush 39 earthed via a friction contact 40. The receiver is switched off when no telegraphy pulse frequencies are received for half-a-minute. Paper, web-feeding arrangements.-The paper 12 on supply roll 13 is advanced by the transport roller 10 and idler roller 11 continuously and in synchronism with the wheel 3 so that one rotation of the wheel 3 which corresponds to a line length corresponds to a paper feed of two line spaces. The transport roller 10 is driven by the motor 9 via a reduction gear (not shown).