Patent GB-784823-A (GB)
Title: Facsimile transmitter
IPC: H04N1/00
Filed: 1956-02-03
Abstract: 784,823. Copying-telegraph transmitters. CREED & CO., Ltd. Feb. 3, 1956 [Feb. 4, 1955], No. 3465/56. Class 40 (3). In a facsimile transmitter in which the subject-matter on a message sheet is scanned by a light beam which is oscillated back and forth across the sheet at a scanning line position, the sheet-feeding mechanism comprises means automatically operative to advance the sheet at a rapid rate until the beginning of the message reaches the scanning position, means automatically operative to reduce the rate of advance until the scanning of the message is complete when further means operates automatically for again advancing the sheet at the predetermined rapid rate. Sheet-feeding arrangements. The message sheet S is inserted so that it is engaged at the initial line or portion to be scanned by rollers 22 and 104, the former being mounted on lever arms and being raised by a handle 24 to facilitate the positioning of the sheet. The transmitter cannot be started when the handle is in the raised position as a switch 46 in the operating circuit is not closed until the handle 24 is lowered. The duration of the slow feeding-operation for the scanning of the subject-matter is set by a carriage member 47 connected to a chain 54 passing over sprockets 58, 58<SP>1</SP>, the movement to the position corresponding to the end of the message rotating anti-clockwise a wheel 56 carrying a pin 62 which engages an arm 64 operating a switch 66 when the final portion of the subject-matter has passed the scanning position in the aperture 44<SP>1</SP>. For the scanning of a number of messages or of a long message, the carriage is moved back to a final position against a stop 49 in which a pin 74 engages the arm 72 of a switch 70 which nullifies the operation of the switch 66 in the subsequent control operation. The feeding of the sheet S is effected by pairs of rollers comprising feed rollers 102, 104, 112 cooperating with pressure rollers 122, 22, 124 respectively. The rapid and slow feeding rates for the feed-out and scanning operations are obtained by driving the feed roller 102 from two trains of gears (94, 96, 98 and 142, 144, 146) of different ratios driven through two overrunning clutches 100, 166 from a motor 90 which can be reversed so that for one direction of rotation one of the clutches is operative, whilst for the reversed rotation by the motor the other clutch is operative to drive its associated gear train and the feed roller at the different rate. When the sheet has been inserted and the handle 24 lowered, a switch 84 is operated so that the scanning motor 210, Fig. 12, and a motor 212 driving a chopper wheel 214 are energized. After a short interval, the motor 90 operates to produce the rapid rate of feeding. A disc 152 driven by sprockets 136, 138, 140 and clutch 154 from the operative gear train, connected by clutch 100, has a pin 150 which is brought into engagement with a pin 148 on a disc 132 carrying a spring-biased arm 130 which is arranged to operate a switch 126 when the first line or portion of the message has reached the scanning position. The operation of the switch 126 reverses the motor 90 which through the other clutch 166 and associated gear train advances the sheet S at the scanning rate. A timer motor operated at the same time drives the sprocket 58 and the chain 54 to move the carriage 47 towards its stop position 68 and also via gear 60 rotates the wheel 56 so that the pin 62 operates the switch 66 which effects the reversal of the motor 90 and the change to the rapid feed rate, which continues until the paper has been fed past contacts 80 normally held open by the message sheet. The switch 126 operated during such revolution of the disc 132 is without effect until switches 82, 180 have been operated by the passage of paper into the bin 187 and its subsequent operation immediately arrests the motor 90 so that the discs 132,152 are in a predetermined position for the initiation of the next transmission. Scanning arrangement and optical system. The scanning arrangement including a beam oscillated by a spherical mirror is generally similar to that described in Specification 778,985, the mirror 236 being oscillated by a spiral track cam 241 on a shaft 222 driven by a motor 210, and which carries cams 246, 250 operating contacts 248, 252 for the control respectively of phasing and of blanking by the arrangements described in either of the Specifications 729,783 and 739,594. If the scanning beam passes beyond the lateral edges of the sheet being scanned a cylindrical mirror 188, Fig. 5 (not shown) disposed behind the scanning aperture 44<SP>1</SP> reflects the beam to a blanking photo-cell 270 which is effective to suppress transmission. The beam reflected from the sheet S is reflected by a cylindrical mirror 260 to two elongated photo-cells 268, one only of which is shown in Fig. 14. Light from the sheet S which would normally pass through to the lateral openings between the mirror and the sheet is reflected by side mirrors 292, 294 to the photo-cells 268. Circuit arrangements, Fig. 13. To initiate operation, a switch 300 is closed and with the message sheet inserted and the handle 24 lowered the switch 46 is closed. When the end-of-message carriage has been moved away from its position against stop 68 and has been adjusted to its appropriate position, the switch 66 is closed and the operation of the push button 84 connects the power supply to connector 310 and the line equipment. After a few seconds a relay arrangement in the line equipment completes a circuit over contacts 66 and through relay 322 which causes operation of relay 328 which locks up over normally closed contacts of switch 126. Over armature 389 and contacts 390 a circuit is completed for the motor 90 which rotates to provide the rapid paper feed. When the first line reaches the scanning position in the aperture 44<SP>1</SP>, the switch 126 closes contacts 356 and operates relay 346 which reverses the connection to the motor 90 and at contacts 366 removes the short circuit of the outgoing line connected to the control apparatus by connections 372, 374. Simultaneously, with the energization of relay 346, the timer motor 170 is operated, and at the end of the message, contacts 66 open causing the release of relays 322, 346 de-energizing the timer motor 170 reapplying the short circuit to the line and effecting the reversal of the motor 90 to provide the fast feed. During this operation the contacts 338 of switch 126 are opened for each revolution of the disc 152 but contacts 180 are closed until the message sheet has passed to the bin. The next operation of switch 126 after contacts 180 have opened results in the release of relay 328 which disconnects the A.C. supply from the motor 90 which receives a pulse from capacitor 348 and resistor 359 to bring it to rest. In the case of a long message, the rearward setting movement of the carriage 47 closes contact member 70 energizing relay 380 which at contacts 378, 379 transfers the function of contacts 66 to contacts 82 held closed by the paper until its end has passed the actuator arm 80. The carriage 47 opens contacts 70 at the end of its travel but relay 380 remains operated over its contact 381. When the end of the message sheet passes the actuator 80, the switch 82 opens and initiates the fast feed-out operation which continues until the contacts 180 are opened, as previously described. To terminate the transmission prior to the operation of the end-ofmessage device, the operation of a reject button 400 opens contacts 403 which through relay means in the line equipment opens the return operating circuit of relay 322 which releases with consequent release of relay 346 and the reversal of the motor 90 to effect the fast-feed operation. If the reject button is operated at or near the start of a transmission, the switch 126 may be operated before the message sheet has reached the actuator for the contacts 180 so that relay 328 is released to stop the feed. The feed-operation can be resumed by operating the button 400 to close contacts 405 and reenergize relay 328 which through contacts 390 re-operates the motor, the operation being repeated until the contacts 180 are closed after which the fast-feed operation will continue until the message sheet has been ejected from the machine.