Patent GB-1169915-A (GB)
Title: Facsimile System
IPC: H04N1/32
Filed: 1966-09-27
Abstract: 1,169,915. Copying telegraphy. XEROX CORP. 27 Sept., 1966 [1 Oct., 1965], No. 43081/66. Heading H4F. The Specification describes a facsimile system of the type using the public telephone system as the medium carrying the video and control signals from the transmitting station to the receiving station and provided with means detecting a malfunction at either station and sending a corresponding alarm signal to both stations. The equipment at each station comprises, Fig. 1, a closable cabinet 127, for holding the telephone handset and a unit 120 comprising means 124/126 for holding a document to be scanned for reproduction, and drum means 122 for supporting a paper on which the facsimile is to be produced. Transmitting system, Fig. 8.-The document to be scanned is placed face down on a moving platen over a scanning slot 303. The document is illuminated by lamps 181 and is moved in line width steps by a stepped motor 178 driving platen wheels 177. A mirror 184 is oscillated by galvanometer 183 such that with the stepped movement of the document, the light reflected from the document by the mirror on to a photo-multiplier 186 performs a raster scan of the document. The correct positioning of telephone handset in cabinet 127 is detected by closure of switch 308 which applies - 6V to one end of relay coils K1 and K2. The energization of relays K1 and K2 is completed by the closure of switches 306 and 307 on respectively detecting the presence of the document and the pressure of the document leading edge at the scanning slot 303. Actuation of relays K1 and K2 produces a transmit (T) signal at the output of amplifier 313 via contact K1a and causes the locking on of relay K1 via contact K2a for the duration of the document's presence. At other times a receive (R) signal is present at the output of amplifier 323. Motor 178 is also actuated via contacts K1b and Klc Means, not shown, determines when subject matter, e.g. print is being scanned, as against blank sheet, and actuates relay K6 such that a fast scan rate from means 319 is changed to a normal slower scan rate from means 320. The T signal actuates relay K4 and so connects a two-tone modulator 314 modulated by the amplified output of photo-multiplier 186, plus control signals, to a loud-speaker 309 in proximity with the telephone microphone. Absence of the T signal applies the low tone output of an alarm oscillator 315 to the loudspeaker. Signals received by the telephone are detected by inductive pick-up coil 311 and are passed to demodulator 316 which extracts the facsimile information and the control signals, and to alarm demodulator 318 which detects an alarm signal (the foregoing only applies when the apparatus operates in a receiver mode). Receiving system. Fig. 12.-The reproducing system comprises a drum 122 rotated by motor 150 in synchronism with the output of means 320, Fig. 8, in the remote transmitting system and carrying the copying medium, e.g. pressuresensitive paper, xerographic paper &c. A pen 154 is carried on a screw 159 which is rotated in the forward direction by stepped motor 160 and is rotated rapidly in the reverse direction by motor 161. The forward stepped motor of pen 154 is in synchronism with the stepped motion of the document. Complex synchronization means are described to bring about the required synchronization. When the pen 154 reaches its upper limit or finish position a switch 613 is closed during the actuation of relay K3. This causes the locking of relay K3 via switch 612 and contact K3a and the switch over of power via contacts K3d, K3e from forward motor 160 to reverse motor 161. Pen 154 thus rapidly returns to the start position, opening switch 612 and de-energizing relay K3. Three bi-stable circuits 620, 621, 622 detect various malfunctions in the system and causes the energization of relay K5. This causes the actuation of loud-speaker 624 by alarm oscillator 315 via contact K5b and the locking of relay K5 via contact K5a and alarm reset button 130. Actuation of button 130 to stop alarm energizes relay K3 and pen 154 returns to start position to produce a non-faulty facsimile. When the illustrated arrangement is operating in the transmitting mode, circuit 622 detects an alarm at the remote-receiverstation. Circuit 621 detects loss of transmit (T) signal and circuit 620 detects loss of receiver synchronization or unavailability of further recording capacity, i.e. actuation of switch 613.