US2351231A

US2351231A - Automatic facsimile telegraph system

Info

Publication number: US2351231A
Application number: US449548A
Authority: US
Inventors: Garvice H Ridings
Original assignee: Western Union Telegraph Co
Current assignee: Western Union Telegraph Co
Priority date: 1942-07-03
Filing date: 1942-07-03
Publication date: 1944-06-13
Anticipated expiration: 1961-06-13

Description

June 13, 1944. e. H. mamas AUTOMATIC FACSIMILE TELEGRAPH SYSTEM Filed July 3, 1942 2 Sheets-Sheet 1 MESSAGE DEPOSIT BEING MESSAGE MESSAGE TRANSMITTED ACCEPTED AMPLIFIER INVENTOR G. H. RIDI NGS EAT%RNIY 7 FIG. 3

0 2 I I 6 9 E ll 6 AMI .1 N W. M um T A PN MI E MV R A l 0(I G w I T I [S E SE I l I EL L SR I E 3 l. I L T M I I m I I I 1 2 2 e N Y 1. e O! 5 w m m 3 a ab t 2 a m n w G, A 2 m a, T s Y s m m m sum w Gm m NE ITS mEv. RLl .1 .MJ R HI E 5d .08 W nu F C M T. A u o w A 9 1 3 1 m A m c R A M Patented June 13, 1944 AUTOMATIC FACSIMILE TELEGRAPH SYSTEM Garvice H. Ridings, Summit, N. 3., assignor to The Western Union Telegraph Company, New York, N. Y., a corporation of New York Application July 3, 1942, Serial No. 449,548

7 Claims. (Cl. 1786.6)

The present invention relates to facsimile telegraph systems, and more particularly to a message sheet operated control system for terminal equipment.

In Patent No. 2,262,715, granted to R. J. Wise et al. on November 11, 1941, entitled System and apparatus for automatic facsimile telegraphy," there is disclosed and claimed a facsimile machine suitable for use as a transmitter. A conveying chute is provided for guiding the message blank so that it may be positioned in the machine for scanning. The facsimile signals which are generated by the scanning operation are transmitted to a central station where they are employed to reproduce the subject matter on a recording machine. In this patent the various functions of the transmitter are remotely controlled by an attendant at the central station. This transmitting apparatus is provided with means for gripping and wrapping the message blank around a, rotating cylinder. After the scanning operation, the attendant at the central station manipulates a control switch which actuatss mechanism at the transmitter for removing the message blank from the rotating cylinder and depositing it in a storage bin.

In another patent to R. J. Wise et al., No. 2,255,868, granted September 16, 1941, and entitled System and apparatus for facsimile telegraphy, there is disclosed a facsimile machine which is provided with facilities for automatic operation. The recording blanks are mounted upon cylindrical copyholders which are adapted to-be inserted in the recording apparatus one at disclosed in Patent No. 2,262,715 and a recorder of the type disclosed in Patent No. 2,255,868.

It is an object of the instant invention to provide novel interconnections between an automatic facsimile transmitter of the slot loading type and an automatic facsimile recorder of the drum changing type whereby certain of the functions of each facsimile machine may be automatically controlled by a special signal generated at the other machine.

Another object of the invention is to provide in a novel manner for conditioning an automatic facsimile transmitter to receive a sheet bearing subject matter to be transmitted only when the recording apparatus is in operative condition to receive and record facsimile signals.

A further object of the invention is to provide in a novel manner for operating the sheet removing mechanism at the transmitter under the control of the recording apparatus.

Still another object of the invention is to provide a novel arrangement for generating and utilizing an end-of-message signal whereby a more economical use of the line time may be made.

The means for attaining the aforementioned objects, together with more specific objects, will become apparent from the following description a time. A copyholder supporting and recording sheet is rotated and scanned in a direction parallel to the axis thereof by a stylus member which bears upon the recording sheet and has impressed thereon electrical potentials representative of the picture elements. The machine disclosed in this patent is provided with a mechanism for removing a copyholder from an operative position in the machine and for replacing it with another copyholder supporting a blank recording sheet. Means are also provided for storing a plurality ofcopyholders, supporting recording sheets, in a magazine from which they may be fed in succession to the facsimile machine. The apparatus disclosed in Patent No. 2,255,868 is suitable for use either as a transmitter or as a recorder, but 0 for the purposes of the instant application, only the recording element will be considered.

The facsimile system which forms the novel subject matter of the present application is emof an illustrative embodiment of the invention making reference to the accompanying drawings in which:

Fig. 1 is a schematic representation of an automatic facsimile transmitter of the slot loading type, together with the control apparatus and electrical circuits therefor;

Fig. 2 is a schematic representation of an automatic facsimile recorder of the drum changing type, together with the control apparatus and elecrical circuits therefor;

Fig. 3 is an illustration of a typical message blank to be used in conjunction with the endof-message control apparatus shown in Figs. 1 and 2; and

Fig. 4 shows a conventional printing stamp having printing means for stamping an end-ofmessage marking.

The end-of-message feature of the present invention is illustrated and described in connection with a facsimile system designed to be installed between a central telegraph office and a remote branch ofiice or agency which has suflicient business with the central station to warrant the installation of an exclusive circuit. A system of this type is disclosed and claimed in a copending application of .G. H. Ridings et al., Serial No.

ployed to interconnect a transmitter of the type 370,748, filed December 19, 1940.

The automatic transmitter located at the which may be selectively illuminated to give an indication of the performance of the machine. The machine is housed in a casing provided with a slot which is in communication with a chute leading to the scanning mechanism. The chute may be opened or closed at various times during the operation of the machine so as either to permit the insertion of'a message blank or to prevent such an operation. At the branch office the desired message is written on a specially prepared blank which is inserted in the conveying chute at the proper time and is seized by the transmitting mechanism and placed in position for scanning, which operation follows immediately. The facsimile signals which are generated by the scanning operation are transmitted to the central station, at which place they are applied to a recorder which, preferably, is at all times preparedto' operate. The operation of the recorder is also automatic and the attendant at that station has only to keep the machine supplied with copyholders bearing blank recording sheets and to remove the sheets upon which recordings have been made from the copyholders which are automatically discharged from the recorder.

Referring to the drawings, the transmitting apparatus illustrated in Fig. 1 comprises a cylindrical copyholder Ii which is mounted for rotation in suitable bearings. Adjacent one end of the cylinder ii is a plurality of teeth i2 arranged circumferentially and extending outwardly from its surface. A pressure roller I3 is suitably journaled and bears against the surface of-the cylinder II. The roller I3 is provided with a groove i4 which is of suitable dimensions to accommodate the gripping teeth l2. A chute or guideway i5 is located so that its lower opening is adjacent to the surface of the cylinder II at the point where it is contacted by the roller i3. The upper end of the chute i5 is flared to form a lip i 6 which facilitates the insertion Of a flexible message sheet. An angular slide i1 is disposed at the mouth of the chute ii in such a manner that it normally blocks the chute, thereby preventing the insertion of a message sheet. The'positlon of the blocking slide I1 is controlled by an electromagnet or solenoid It, the armature of which is connected to the slide. When the solenoid I 8 is deenergized. a compression spring l9 mounted upon the armature forces the slide ll into the closed position. but upon energization of the solenoid the armature is drawn against the action of the spring i9, thereby moving the slide ll from its blocking position. A message sheet 20 may be inserted in the chute l5 by which it is conveyed by gravity to a point where it is stripped between the roller l3 and the cylinder [I which is continuouslv rotated. The message sheet 23 is pierced by the teeth I! and is drawn downward from the chute and wrapped around the cylinder i l in a position to be scanned.

An optical scanning system is prov ded which ncludes an exciter lamn 2 i. the l ght from which is condensed by a lens 22 so that a. small spot of light imp n es on the message sheet 20 and is reflected from it in an amount dependent upon the tonal density of the elemental area. scanned. The reflected li ht is a ain condensed by another lens 23 into a noint wh ch lies n the plane of a light chopper 24. which may be in the form of a perforated disc o as illustrated. a disc having notches such as 25 formed in the periphery thereof. The disc is mounted upon a shaft which is rotated at the desired speed by means of a suitable electric motor (not shown) whereby the light reflected from the message sheet 23 is alternatel transmitted and interrupted at a rate dependent upon the speed of rotation of the light chopper disc 24 and the number of openings provided therein. The light pulsations which are transmitted through the chopper disc 24 impinge upon a photocell 23 and thereby generate alternating current signals which are modulated in amplitude in accordance with the tone values of the elemental areas of the message sheet 23.

The entire optical scanning mechanism is mounted in a carriage 21 which is suitabl arranged for sliding movement, in a direction parallel to the axis of rotation of the cylinder Ii, upon a rail system such as 23, or in any other suitable manner. The carriage is normally urged toward the left hand end of the machine by means of a spring 23. When a scanning movement of the carriage 21 is desired. a half-nut II is moved into engagement with a continuously rotating feed screw 32 by means of an electromagnet 33. The feed screw 32 and the cylinder ii may be rotated at their respective rates by means of a single driving motor (not shown) coupled thereto through appropriate reduction gearing. s The cylinder II is also p figided with a groove 34 which extends cirdiimfeiientially thereof and which, when there is .no message sheet in position upon the copyholder, is adapted to receive the end of a small rod 35 which is secured to a rock shaft 38. A torsion spring 21 is connected to the rock shaft 36 and to any convenient supporting member such asa bearing bracket 33 and tends to rotate the shaft 33 in such a manner as to force the rod 35 into groove 34. The rock shaft 36 also carries the movable contact of a transmitting blank controlled switch 39. When there is no message sheet on the copyholder and the rod 35 is in the groove 34, the switch contacts 39 are closed. However, as soon as a message sheet 20 is secured on the copyholder II, the rod 35 is raised from the groove 34. and the contacts 39 are opened for a purpose which will be described later.

The transmitting apparatus is provided with a mechanism for removing the message sheet 20 from the cylinder ll. shorter than the circumference of the cylinder II by an amount sufllcient to leave a small gap between its ed es when it is wrapped around the cylinder. A pivoted blank stripping member 4| is provided with a sharp end and is so located that. when it is pivoted under the influence of an electromagnet 42. the sharp end is placed in position to slip under the leading edge of the messa e sheet as it is rotated, thereby progressively ulling the sheet away from the cylinder and disenga ing the perforated section from the teeth i2. The message sheet thus detached from the cylinder II is permitted to drop into a bin or ther convenient compartment.-

The recording apparatus installed at the central office is shown diagrammatically in Fig. 2 and in detail in the aforementioned Patent No. 2.255368. The recording machine comprises a convholding drum 43 which is cylindrical in form and is provided with two axially extendin arbors 44 and 45. Centering

spindles

46 and 41 are arranged to cooperate with the drum arbors to support the drum for rotation. An arm 43 is pivoted on the spindle 46 and extends in the direction of the drum to engage a pin The message sheet is.

anism is a friction clutch as which permits the spindle 40 to stop while the motor is running. A disc 50 having a notch formed in the periphery thereof is secured to the spindle 44. A stop arm or latch 51 is arranged to engage the peripheral notch of the disc when acted upon solely by a retractile spring 80. Upon energization of an electromagnet 00, which is referred to hereinafter as the framing magnet, the latch 51 is lifted and disengaged from the notch in the disc 50 to thereby permit rotation of the spindle 40.

A recording sheet 0| is wrapped around the drum 4: and is secured thereto by one or more circular elastic members such as 02. The sheet [I is mounted on the drum so that the lap 03 formed therein invariably bears a definite relation to the notch formed in the disc 50. Such an arrangement is for the purpose of securing the proper phasing or framing between the recorder and the branch oflice transmitter and will be subsequently described in greater detail.

A carriage 04 is arranged to slide on a pair of rails 05 disposed parallel to the axis of rotation of the drum 43. An electromagnet II is mounted on the carriage and. when energized, serves to pivot a lever 01 into the retracted position shown in the drawings. A recording stylus I0 is attached to one extremi y of the lever l1 and, as illustrated, is held out of engagement with the recording sheet 0| during idle periods. A half-nut 09 is also attached to the lever 01 and is adapted to engage a threaded feed screw II which is rotated at a suitable speed by the driving motor 53 acting through its associated reduction gearing 54. When the electromagnet 00 is deenergized, the lever 01 is moved by means of a spring 12 in such a manner that the hall'- nut 09 engages the feed screw II and the stylus 00 is brought into contact with the surface of the recording sheet 8|. The engagement of the half-nut with the feed screw resul s in movement oi the carriage 04 toward the right, as viewed in this figure, against the restraining action of a retractile spring 13. Obviously, at the end of a scanning operation, when the lever 01 is pivoted to disengage the half-nut from the feed screw, the carriage is returned by means of the retractile spring to the extreme left hand position shown.

The recording machine illustrated is provided with facilities for automatically discharging a drum after a recording operation and for feeding another drum into the machine. The machine is normally provided with a copious supply of drums, each bearing an unmarked recording sheet GI one of which, 14, is shown fragmentarily in dot and dash outline. A rack or magazine is used to store the drums and comprises two rail members 15 and 10 mounted on a pair of supporting brackets 11 and I0, respectively, and spaced apart slightly more than the length of a drum 43. A pair of resilient upright members 19 and 8| are secured to the rail members l5 and 10, respectively, and cooperate with an auxiliary pair of spaced rails 02 and 03. respectively, to guide the stored drums toward the scanning device. The drum 14 awaiting positioning in the facsimile recorder is held in readiness by having its arbors, one of which, 04, is shown in Fig. 2, supported by the upper end of a pair of detents, one of which, 05, is shown. Each of the detents 05 is pivoted adjacent its lower end on the respective rail members and is normally held in this drum restraining position by means of a pair of resilient members such as the spring 00 attached thereto and also to the rail member II.

Upoh completion of a scanning operation, a drum changing motor 0! is started and drives a worm gear 00, which in turn drives a cooperating pinion gear 09. The pinion gear is keyed to a shaft 9| upon which is also secured a pair of cams 02 and 03. A bell crank 94 is pivoted on any convenient stationary member such as the bracket 90- and is provided with a forked portion 04 adjacent the extremity of one arm thereof and also with a rod or cam follower 01 adjacent the extremity of the other arm. Rotation of the shaft 0| brings the raised portion of the cam 92 into engagement with the rod 01, thereby pivoting the bell crank 94 and bringing the bifurcated portion 96 into engagement with a pair of pins attached to the spindle 41. Further movement of the bell crank 04, caused by the continued rotation of the cam 92, moves the spindle 41 toward the left, as viewed in the drawings, against the action of a spring 00, one end of which is attached to a pin |0I extending from the spindle and the other end of which is secured to a stationary bracket I 02.

The withdrawal of the centering spindle 41 asdescribed permits the drum 48 to drop so that its arbors 44 and 45 rest in a cradle formed by notches in a pair of members I00 and I04. These members are secured adjacent their lower extremities to a rock shaft I05 which is suitably Journaled in bearings mounted in any convenient fixed brackets. Also secured to the rock shaft I 05 is an arm I00 carrying at its outer extremity a cam follower in the form of a roller I 01. This roller is adapted to cooperate with the cam 03 so that, when the shaft 0| is rotated by means of the mechanism driven by the motor 81, the engagement of the roller I01 with the raised portion of the cam 93 results in a clockwise movement of the arm I08, as viewed from the left hand end of the facsimile machine, thereby imparting a rocking movement to the spaced members I03 and I04.

As the rock shaft I05 is rotated as described, the cradle members I03 and I04 are moved forward until a position is reached whereby the drum 43 is permitted to roll from the notches formed in these members into any suitable receptacle or conveyor. A continuation of the rocking movement brings the upwardly extending arms I00 and I09, respectively, of the cradle members I00 and I04 into engagement with the respective detents such as 85. These detents are thus moved out of the downward path of the arbors such as 84 of the drum 14, thereby permitting this drum to drop so that its arbors rest upon the upper ends of the arms I08 and I00. When, by continued rotation of the cam 93, the rock shaft I05 is permitted to return the cradle members I 03 and I04 to their upright position under the influence of the spring III attached to one of the members and to any convenient stationary member, the upper ends of the arm I 00 and I0! are withdrawn from under the arbors 44 and 45 of the drum 14, thereby allowing these arbors to roll into the notches formed in the cradle members. The new drum 14 is thus carried into a position such that, when the cradle .mexnbers have been fully restored to their upright positions, the indentations formed in the ends of the arbors may be engaged by the conical centering points formed

onsthe spindles

46 and 41. Prior to this engagement, the axis of the drum which rests in the notches of the cradle members lies slightly below the center of rotation provided by the centering

spindles

46 and 41. However, because of the conical configuration of the ends of these spindles, the subsequent movement of the shaft 41 toward the drum is instrumental in lifting the drum slightly so that it may rotate freely.

The initiation of the drum changing cycle just described is effected by applying power to the motor 81 subsequent to a scanning operation, or at any other desired time, by a means which will be described more fully in the following portion oi the specification. A cam II 2 is mounted on the cam shaft 9I for cooperation with the movable contact of a pair of contacts H3. The cam I I2 is oriented with respect to the cams 92 and 93 so that at the completion of a drum changing cycle the contacts II3 are opened momentarily. It will be seen from the following portion of this specification that the momentary opening of these contacts causes power to be disconnected from the motor 81. However, the mechanism-is so designed that before the motor can be brought to a stop by means of a braking system the cam II2 becomes disengaged from the contact members, thereby permitting the reclosure of the contacts II3.

-The circuit interconnecting the transmitter of Fig. l and the recorder of Fig. 2 comprises a pair of conductors LI and L2 which are used simultaneously for the transmission of the alternating current facsimile signals and the direct current control signals, by means of which the operation of the transmitting and recording apparatus is controlled. The facsimile signals originate at the photoelectric cell 26 which is connected to an amplifier H4, the output circuit of which is connected through a pair of blocking condensers H5 to the conductors LI and L2. The purpose of the condensers H5 is to isolate the alternating current facsimile signals from the direct current control signals. At the recording station of Fig. 2 the line conductors LI and L2 are connected through another pair of blocking condensers I I6 and through an adjustable pad II1 to an amplifier H8. The output of this amplifier is connected to a signal inverter N9, the output circuit of which is arranged to be connected between ground and the recording stylus 68. The polarity of the direct current potentials which are applied to the conductor LI is controlled by the apparatus at the recording station for the purpose of operating a polar relay I2I connected to this conductor at the transmitting station. Similarly, the polarity of the direct current potentials which are applied to the conductor L2 is controlled by the apparatus of the recording station forthe purpose of operating a polar relay I22 connected to this conductor at the transmitting station. Both of these polar relays are of the three-position type whereby the armatures thereof are moved to one extreme contact in response to one polarity of potential, to the other extreme contact in response to the opposite polarity of, potential, and to a mid-position disengaged from both of the extreme contacts in response to a no-current condition. These polar relays HI and I22 are non-responsive to the altemating current signalsgenerated in the photocell 26.

The operation of the foregoing facsimile apparatus will be described in conjunction with Figs. 1 and 2 taken together. Prior to the start of a series of operations, it is assumed that power is supplied to the transmitting apparatus by the movement of a switch I23 to it left hand contacts, thereby connecting a source of alternating current potential I24 to the bus bars A and B. The driving motor for the cylinder II and the feed screw 32, and the motor for the light chopper disc 24, indicated diagrammatically at I25 and I26, respectively, onFig. 1, are thus energized to rotate the equipment coupled thereto. Also, the exciter lamp 2| is illuminated, thereby providing for the generation of alternating current in conjunction with the photocell 26 and the light chopper 24 by reflection from the surface of the cylinder II. Similarly, power suitably rectifled where necessary is applied to the amplifier H4 in any conventional manner (not shown).

At the recording station, power is supplied from a source of direct current potential I21, which in this case is of positive polarity. Negative direct current potential is also supplied from a source I28, as specified hereinafter. The driving motor 53 is supplied with alternating current energy which is synchronous with the transmitter alternating current power supply.

A relay I29, adjusted for margina1 response to current values higher than the current values normally produced to effect operation of the polar relay I2I, is included in circuit in the conductor LI at the receiving station. The relay I29 is also of the type which is slow to release. A resistor I3I is also included in circuit with the polar relay I2I in the conductor LI at the transmitting station to control the magnitude of the current of the marginal relay I29. A relay I32 at the transmitting station is energized from the bus bars A and B by way of the recording blank controlled switch contacts 39 when the cylinder I I is not supporting a sheet 20. With a sheet 20 on the cylinder as shown in Fig. l, and even with the switch I 23 closed, the relay I 32 is deenergized to short-circuit the resistor I3I upon closure of its make contact I33 and thereby raise the current flowing in the conductor LI to the higher .value. The marginal relay I29 responds by opening its break contact I34. Before the message sheet 20 is mounted on the cylinder II, the contact I34 is closed, as shown, to apply ground to the left hand winding I36 of a phasing or framing relay I31. A tongue and make contact I38 of this relay applies ground to energize a relay I39 to connect ground through its make contact Hi to energize the electromagnet 66 to move the half-nut 69 and the stylus 68 into their disengaged positions. This is the idle condition of the receiving apparatus, which it-will also assume when the switch I23 at the transmitter is opened.

At least a part of the plate current for the amplifier H8 is supplied from the source I21 through the winding of a relay MI. The signals which are generated at the transmitter by the photocell 26 under the described idle condition are of maximum amplitude whereby the amplifier II8 draws a current sufficient to energize the relay I4I to maintain its make contacts I42 and I43 in circuit closing position. The contact I42 energizes the right hand winding of the relay I31 in preparation for the phasing operation to be described.

It is assumed that the recording apparatus is not provided with a drum 43 in operative position for-recording. The spindle 41 is thus permitted to move farther to the right than its normal position when it engages the arbor of a drum and in doing so effects the engagement of a pin I43 carried thereby with a set of overthrow contacts I44. The closure of the contacts I44 connects ground to the operating winding of a relay I48, thereby preventing the connection of the negative battery I28 to the line conductor LI at its break contact I41. Consequently, at the transmitting station the polar relay I2I will be maintained in its neutral or mid-position.

In order initially to place the facsimile apparatus at the recording station in condition for operation, the attendant will place a number of drums 43 equipped with blank record sheets in the magazine 01' the recorder. The first of such a series of copyholders is inserted in the recorder by momentarily operating a push button I48, which closes a contact I48 to place a ground on one terminal of the left hand winding of a relay II. The other terminal of this winding is connected through the closed recorder cam contacts I I3 to the source of positive potential I21, thereby causing this relay to operate. Operation of the push button I48 also energizes a relay I52, which in normal automatic operation of the drum changing equipment is energized from a make contact I53 of the relay I5I. The relay I5I is looked through its make contact I53 so that the push button I48 may be released. The operation of the relay I52 connects an additional ground to the stylus magnet 88 through its make contact I54, thereby insuring that the stylus will always be raised when the cycling mechanism for changing the drums 43 is in operations The other make contact I55 of this relay completes a circuit to energize the drum changing motor 81. This motor drives the previously described drum changing mechanism through a cycle of operations resulting in the placing of a drum in operative recording position in the machine. At the completion of this cycle, the cam contact H3 is momentarily opened, thereby interrupting the locking circuit of the relay I5I, permitting this relay to be released and thereby releasing the relay I 52. Thus, power is disconnected from the copyholder changing motor 81 and one of the grounds removed from the winding of stylus mag- 'net 65.

With a drum in position in the recorder, the spindle 41 is withdrawn sufficiently to permit opening of the overthrow contacts I44, thereby deenergizing the relay I48 and connecting the source of negative signaling potential I28 to the conductor LI at its break contact I41. This circuit extends from the source I28 through the make contact I43 of the relay I, through the break contact I41 of the relay I48, through abreak contact I58 of the relay I5I and through the winding of the marginal relay I28. The re lay I is energized at this stage of the operation, since the transmitter scanning apparatus is generating an alternating current, as stated above, and the relay. I5I which serves as an endof-message relay under control of a relay I51 in a manner to be described is deenergized.

The negative potential of conductor LI operates the polar relay I2I at the transmitting station to effect the engagement of its armature with its spacing contact S. A connection is then established from the bus bar A through the spacing contact S of the relay I2 I, through the winding of the solenoid I8 and a make contact I58 of the relay I32 to the bus bar B. Connected in shunt with the solenoid I8 is a lamp I58 which is lighted to illuminate a sign reading Deposit message. Simultaneously therewith the energization of the solenoid I8 withdraws the slide I1, thereby opening the chute I5.

Facilities are provided at the central oflice for controlling the transmitting and receiving apparatus in such a manner that the scanning operation is continued only as long as is necessary to completely scan the subject matter. The message to be transmitted is inscribed on a blank sheet 28 provided for the purpose and in accordance with the invention is to be marked by the attendant at the branch oflice so that the end-ofmessage feature will function at the proper time.

The sheet 28 of Figs. 1 and 3 is shown as having an end-of-message marking I8I in the form of a series of bars. The marking I8I may be conveniently applied with a rubber stamp I82 of the conventional type, shown in Fig. 4 of the drawings. The printing face of the stamp is provided with type markings I83 in relief which may be inked to' produce the marking IBI on the message sheet 28. It will be understood that the marking I8I may be of any desired pattern or type, as will appear in the description hereinafter given of the end-of-message feature of the invention.

The sheet containing the message, after being marked as with the stamp I82, is then inserted in a chute I5 by means of which it is carried to the scanning apparatus where it is engaged and placed in position for scanning as previously described. The wrapping of the message hearing sheet 28 on the cylinder II disengages the arm 35 from the groove 34, thereby opening the contacts 38. This operation results in the release of the relay I32, which extinguishes the Deposit message lamp I58 and deenergizes the solenoid I8, thereby closing the chute I5. The release of the. relay I32 closes its break contact I33, thereby to short-circuit the resistor I3I and cause an increase in the value of the signal current flowing in the line LI.

This current value increase causes the relay I28 at the recording station to break the circuit through the winding I38 of the relay I31 at its break contact I34. However, this relay is maintained operative by means of its right hand winding, which is energized at this time by way of the make contact I42 of the relay I. When a black spot I88, which appears on the sheet 28, is scanned, a facsimile signal having the maximum amplitude is generated and transmitted to the recording station. This event usually occurs during the completion of the first revolution of the cylinder II following the placing thereon of the message sheet 28, since the carriage 21 in its left hand position permits light to be focused on the cylinder II at the point normally covered by the spot I88 when the blank is in position. The response by the amplifier II8 to such a signal reduces the plate current sufficiently to permit the release of the relay I4I, thereby opening its make contact I42 and completely ,deenergizing the relayI31 and effecting its release. The opening of the contact I38 of this relay deenergizes the relay I38, which, through the opening of its make contact I48, deenergizes the electromagnet 88, thereby permitting the engagement of the half-nut 88 with the feed screw H and the engagement of the stylus 88 with the recording sheet 8|. The closure of a break contact "I of the relay I88 energizes the framing magnet 59 to withdraw the latch 51 and permit rotation of the drum 43. The incoming facsimile signals properly amplified and inverted are applied by means of the stylus to the recording sheet 6|. A break contact I12 of the relay I31 places a positive potential on the conductor L2 which causes the tongue of the polar relay I22 to move to its M contact, thereby energizing the half-nut magnet 33 at the transmitter. The "Message being transmitted lamp I13 is illuminated toshow that the recordin process is being carried out.

When the entire subject matter inscribed on the sheet 20 has been transmitted, the light spot scans the series oi marks IBI to thereby modulate the alternating current generated by the photocell 26 in conjunction with the light chopper 24, the frequency of the modulated current depending upon the width of the marks and their spacing and the peripheral speed of the cylinder II. A modulated side band is selected at the receiving station by a tuner I14 which is detected and amplified to energize the relay I51, which is of the type which is slow to operate. The make contact I16 of this relay energizes the right hand winding oi. the relay II through a condenser I18 shunted by a high resistance I19. The slow to operate feature of the relay I51 prevents the relay I5I from responding tomomentary modulation products produced when the subject matter on the sheet 20 is being scanned. The condenser-resistor circuit prevents any false operation of the drum changer in the manner set forth in Patent No. 2,255,868, above referred to. When the right handwinding of the relay I5I is energized, its left hand locking winding is energized by way of the make contact I53 and the cycling contacts H3. The relay I55 is also energized to start the drum changing motor 81. The stylus 68 and the halfnut 69 are positively raised at this time, since the make contact I54 oi the relay applies ground to the electromagnet 66,'as explained above. The drum 43 continues to run, since the relay I39 remains energized until the sheet 20 is removed from the cylinder II of the transmitter. Simultaneously with the drum changing operation, which is initiated by energization of the relay I5I, positive potential is applied to the conductor LI at a make contact IBI of the relay I5I. The slow release relay I29 does not respond to the interruption of signaling current.

At the transmitting station the tongue of the polar relay I2I moves to its contact M, thereby energizing the operating solenoid 42 for the peeling member H which removes the sheet 20 from the cylinder II. A lamp I32 illuminates the Message accepted" sign at this time.

When the sheet 20 is removed, contacts 39 reclose 'to reenergize the relay I32 which reinserts the resistor I3I in the conductor LI by reason of the opening of its break contact I33.

At the recorder, the relay I29 is released to close its break contact I34 and energize the left hand winding I36 of the relay I31. This energizes the relay I33 which stops the dnun 43 and raises the stylus 63 and the half-nut 69. This also removes the positive signal potentialfrom the conductor L2 applied at the break contact I12. At the transmitter, the tongue of the polar relay I22 is centered, which deenergizes the half-nut magnet and allows the carriage 21 to return to its starting position. At the end of drum changing cycle, initiated by the end-ofmessage signal, the negative signaling potential is restored to conductor LI, causing the tongue of the polar relay I2I to move to its contact 8, thus energizing the solenoid I8 to open the chute I5 and light the Deposit message lamp III. This indicates to the attendant at the transmitter station that the next message may be transmitted at once. if desired.

While the invention has been explained in connection with an illustrative embodiment thereof, it is to be understood that the invention maybe embodied in other forms, and therefore the invention is not limited except as indicated by the terms and scope of the appended claims.

What is claimed is:

1. In a facsimile telegraph system, an automatic transmitter, an automatic recorder, means in said transmitter for receiving a message bearing sheet and automatically transmitting signals representative of the message on said sheet to said recorder, means responsive to the receipt of said sheet by said means for preparing said recorder for operation, said signal transmitting means being responsive to a marking on said message sheet for generating a control signal following the transmission of said message representative signals, and control means at said recorder responsive to said control signal for restoring said system to an idle condition in readiness for the delivery of a subsequent message bearing sheet to said sheet receiving means in said transmitter, said control means being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

2. In a facsimile telegraph system, a transmitting device having a scanner, means for automatically presenting a message bearing sheet to said scanner, a chute to convey said sheet to said sheet presenting means, a closure for said chute, a recorder, a signaling circuit interconnecting said transmitter and said recorder, a relay connected to said circuit responsive to a signal generated by an end-of-message marking on said record sheet, and means including said relay andcircuits controlled thereby to withdraw said closure from said chute, thereby preparing said transmitter for immediate use for the transmission of a succeeding message, said relay being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

3. In a facsimile telegraph system, a transmitter having a scanner, conveying means operable to deliver a message bearing sheet to said scanner, means responsive to a marking on said message sheet for modulating alternating current signals generated at said transmitter by a predetermined frequency substantially at the time of completion of a scanning operation, a recorder having a cylindrical drum carrying a record sheet, control means at said receiver responsive to said predetermined modulated frequency for removing a drum carrying a recording from said recorder and placing another drum bearing a blank record sheet in said recorder, and means responsive to the completion of said drum changing operation at said recorder for operatively conditioning said conveying means for reception of a message bearing sheet, said control means being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

4. In a facsimile system, a transmitter, a recorder, means in said transmitter for receiving a message bearing sheet and automatically transmitting signals representative of the message on said sheet to said recorder, means in said transmitter for discharging said sheet from said transmitter, said signal transmitting means being responsive to a marking on said message sheet for generating a control signal following the transmission of said message representative signals, and control means at said recorder respon- -sive to said control signal to control the operation of said sheet discharging means, said control means being responsive to continuous control signals of a predetermined duration and being nonresponsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

5. In a facsimile telegraph system, a transmitter having a copyholder and a scanning device, means to produce relative movement between said copyholder and said scanning device, conveying means operable to deliver a message bearing sheet to said copyholder, a recorder having a copyholder adapted to carry a record sheet, means responsive to a marking on said message sheet for generating a control signal at the end of a scanning operation at said transmitter, control means responsive to said control signal for removing a copyholder from said recorder and placing another copyholder in said recorder, and means responsive to the completion of said copyholder changing operation at said recorder for controlling said means for producing relative movement between said copyholder and said scanning device, said control means being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

6. In a facsimile system, a transmitter, a recorder, ,said transmitter embodying means for receiving a message bearing sheet, means for automatically transmitting signals representative of the message on said sheet to said recorder,

means for discharging said sheet from said transmitter, and said signal transmitting means being responsive to a marking on said message sheet for generating a control signal following the transmission of said message representative signals, control means at said recorder responsive to said control signal to control the operation of said sheet discharging means at the transmitter, and additional signaling means at said transmitter for generating a signal upon discharge of said message bearing sheet, and means at said recorder for restoring the latter to an idle condition in response to a signal from said signaling means, said control means being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

7. In a facsimile telegraph system, an automatic transmitter, an automatic recorder, said recorder being normally in an idle condition awaiting reception of a message, means in said transmitter for receiving a message bearing sheet and automatically transmitting signals representative of the message on said sheet to said recorder, means responsive to the receipt of said sheet by said means for preparing said recorder for operation, means at said recorder for starting said recorder in phase with said transmitter, means in said transmitter for discharging said sheet from said transmitter, said signal transmitting means being responsive to a marking on said message sheet for generating a control signal following transmission of said message representative signals. control means at said recorder responsive to said control signal to control the operation of said sheet discharging means at the transmitter, and means operable upon discharge of said message bearing sheet for restoring said recorder to its idle condition, said control means being responsive to continuous control signals of a predetermined duration and being non-responsive to similar signals of a shorter duration fortuitously occurring in message representative signals.

GARVICE H. RIDINGS.