US2693992A - Facsimile apparatus - Google Patents

Description

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OHARLSJ al R065 OLDE/V United States PatentA Oce 2,693,992 Patented Nov. 9, 1954 i FACSIMILE ABPARATUS Charles J. Young and RogenG..Oldeu1rinceton, N. J.,

assignors to, Radio Corporation-,d A-merica, a corporationof Delaware 4iflpplieation July 7,'"1948," Serial No. 37,3.84 9 ClaimS.- (Cl. 346-10.1.)

simultaneously to produce marks. ona recordingl medium contacted by the electrodesof the couple.y The invention is also concerned with andrelates to novel forms of electrode mountings.

in thedisclosed forms, the inventionk isparticularly adapted to that form of facsimile recording,apparatus wherein the reproduced message isbuilt up in a point by point manner on arecording paper or strip by reason of current flowing through the strip or paper upon which the message is to be produced. Such forms of systems are usually those where the recording on ther-record strip takes place by reasonof a current flowing directly through the medium upon which the record is to be produced, and, accordingly, such systems are generally known irl-the art as recorders of the so-called electrolytic type,,although it is to be understood that in some instances the recordings may develop as a result ofV heat. or'the like produced by current flowingbetween two suitable `electrodes with the recording material interposed therebetween.l

ln apparatus of this general type, it has been customary, as known in the art, to provide a record drum -uponwhich is suitably arranged a helical stripvwhich lextendsusually fromone end of the drum tothe other and covers substantially 360 of the drum.

The drum may have several helices whichcooperate with an electrodel known variously as :a printer bar or apresser bar. The helix and the printerbar ,together provide what may be regarded as Va recording or printing couple. lf a plurality of helices are used; orV ifthc printerv bar cooperatesvwith a single helixvatmorexthan one point, it will thenibe- .obvious :thatla plurality of printing couples are present. ing recordingsby the methods discussedr above, a certain amount of pressure is applied to squeezetherecording medium,A such as paper, between the `printen bar Vand helix, or helices, so thatthe electrical resistance through the paper from one to the other shall.be relatively low.

This pressure, if it is too high, will shear or damage `the sheet. If both the printer bar and the helix yare rigidly mounted, itis impractical to maintain theirarrangement with such precision thatthepaper squeeze is constant. Also, there is a tendency to tear the paper at the side where the advancing helix pushes. under the end of the printer bar. Heretoforc, in-theI prior art; it has been customary to make the printer bar in the form of'a -strip mounted in a plane through the axisiofthey helix, and to support itin a hinged frame, or in a slot, Vand then ,to apply adequate pressure by springs. At modernhigh recording speeds in the vicinity of 1200 R. P. M. to 2000 R. P. M. for the helix drum, the printer bar is easily shocked into oscillation; and because of its considerable mass, it can only be restrained from-oscillation byincreasing the spring pressure to a .point where vthe paper may be damaged.

Thev diiculty .of maintainingv a uniform. and. nonoscillating contact pressure in the recording c ouple has been heretofore one ofthe major limitations in building electrolytic facsimileY recorders for-very high speed 0peration.

In accordance with the invention, therefore, a printer bar of novel constructionis lprovided/which is ilexible radially of the helix but whichz'is. stiff laterally of the printer bar structure and tangentially, of the helix.Vv In For thel purposefofr obtainnormal use of the recording or printing couple comprisinga printer bar and helix, the recording medium is-in general tangential to the helix, or follows-the surface of the helix. Moreover, the printer bar of this invention has the further advantages of being easily adjustable, self-insulating, and relatively quiet in operation in a high-speed recorder. In accordance with the invention, the total mass of thev printer bar is much less and its vertical stiffness is lgreatly reduced without sacrificing the lateral rigidity which insures a straight recorded line across the sheet. Consequently, the effective mass reacting against the helix at any point is only a fraction of the total for the bar. Added to this is the damping effect of f the novel mounting arrangement disclosed herein. As a result, ktherevis practically no tendency for the printer bar of this invention to vibrate even at high drum speeds, and a uniform contact pressure can be maintained along its length. Uniform contact pressure along the length ofthe yprinter bar, when the bar serves to provide one element of one or more recording couples traversing the bar simultaneously and at a very high speed linearly of the bar, is maintained with a bar constructed in accordance with this invention. It will be understood that while a helix or helices are described herein by way of example, the cooperating electrode or electrodes may have another form and provide a moving point or points of contact with the bar of suitable elemental image areas.

Inits application to the so-called electrolytic type of recording, as is illustrated in one form, for instance, by Young Patent No. 2,215,806, a recording sheet or strip is arranged to be impregnated with a chemical solution which issuitably changed when picture modulated signal current ows through it in the reproduction of the picture image, so thatmarking effects are obtained upon the material.. of the. recording sheet. The impregnated paper issuitably advanced relative to the recording drum and the printer bar so as to bring new'sections of the re cording strip. continuously beneath the printer bar. Sig nal energy, as it is received from the communication channel after being suitably amplified, is caused to initiate the ilowcf current between the printer baron the one hand, serving as one, electrode of the system, and the recording helix on the helix drum, serving as the other electrode, on the other hand. The density of the marking in the recordingy strip is, generally speaking, proportional tothe intensity of the current owing.

The principalobject of the present invention, therefore, is to provide a printer bar of novel 'construction which is flexible in a plane normal to the surface of the recording medium upon which the bar rests but is rela tively rigid in Va plane parallel to the recording surface of the recording medium.

A further object of the invention is to provide a novel printer bar which is generally T-shaped in cross-section.

A still further object of the invention is to provide a novel printer bar mounting which permits full advantage tol be taken of the flexibility characteristics of the bar of thepresent invention.

Still another object of the invention is to provide a novel adjustable mounting for the printer bar.

Other objects and advantages of the present invention will,--of course, become apparent and immediately suggest themselves to those skilled in the art to which the in lentionis directed from a reading of the following specicationin connection with the accompanying draw ing in-which:

Fig.` l isa view in` frontelevation of the printer bar and printer bar mounting of this invention in conjunction with a recordingl or helix carrying drum;

Fig-2 is a bottom plan View of` the printer barand printer bar mounting of Fig. l with the drum omitted for thesake of convenience of illustration;

Fig. 3 is a View in cross-section on line 3 3 of Fig. l;

Fig,f,4 is a view of front elevation of another embodiment of the printer bar mounting of this-invention;

Fig. 5 is a View in cross-section on line 5-5 of Fig. 4;

Fig. 6 is a View in front elevation of a further embodiment of the printer bar mounting of the invention; and

Fig. 7 is a view in cross-section taken on line 7 3/ of Fig. .6;

Referring` forthe present to Fig. l of the drawing,

there is shown fragmentarily, and by way of example, a recorder which is suitable for producing marks in accordance with facsimile signals. This recorder may be, generally of the character described in U. S. Patent No. 2,215,806 granted to Charles I. Young on September 24, 1940. By reason of the invention disclosed herein, a considerable improvement in the method of obtaining the nal record and in the` apparatus which embodies features for carrying out the improved method is presented over the general disclosure of the above noted Patent No. 2,215,806 and other patents showing prior art electrical recording arrangements.

In the form shown, the recorder comprises a recording drum 12, provided with a radially projecting helical electrode 14 mounted on its periphery which cooperates with a second electrode in the form of a printer bar 16. The drum 12 may have additional helices thereon, for example, another helix 17. This printer bar member is carried by novel means of the present invention indicated generally by the reference character 18. The means 18 are secured on any convenient stationary portions 19 and 20 of the apparatus in a manner to be described.

Reference character 23 designates a signal or facsimile receiver of any known type, radio or wire line, which is in communication with a signal input source 24.

The incoming signal may be composed of a number of carriers, two for example, each having image or other intelligence modulated thereon for recording. The nature of this intelligence is not of importance in connection with the description of the present invention. Each carrier may, for example, be modulated with signals derived as a result of scanning subject copy by a color separation method. Several of these methods are known to the prior art. The carriers are separated in a channel separator 26 and demodulators 27 and 28 derive signals suitable for recording. These latter signals are applied to the helices 14 and 17 over conductors 31 and 32 which are connected to brushes 34 and 36. The helices 14 and 17 are connected to slip rings 38 and 39 upon which the brushes 34 and 36 bear. It will be understood that the helices will be insulated from the drum 12, or the latter may be made of insulating material. In the illustrative arrangement, the printer bar 16 is connected to a common circuit point, such as ground, for example. However, for a single helix, one of the connections 41 from the receiver 23 which may then incorporate a suitabledemodulator, may be in communication with a brush which bears on the drum shaft 43, or the frame of the apparatus (not shown) and the other terminal or connection 41 from the receiver 23 may be connected to the printer bar 1.

16 to complete the connection to the recording electrodes. 1t will be understood that the single helix will then be conductively connected to the drum shaft and the printer bar 16 will be insulated.

The record sheet or paper web 46 which is threaded between the printer bar 16 and the helical electrode or electrodes is drawn through the recording zone by suitable means (not shown). The drum and paper feed means may be driven in a coordinated manner by suitable means (not shown). Patent Number 2,215,806 referred to above shows such means as well as paper drive means. synchronizing and phasing signals may be generated and transmitted as described in U. S. Patent 2,326,740 granted to Maurice Artzt on August 17, 1943, when desirable or necessary.

Since the elements so far described are well known, per se, and generally of themselves do not form the particular basis of this invention, they are illustrated herein more or less diagramically. Further details of the helical recorder with respect to the paper feeding means and other conventional features are to be found in U. S. Patent Re. 20,152 granted to the present inventor on October 27, 1936. TheA recorder in this last named patent, however, relies on a transfer of marking material to produce markings by Vibrating the printer bar rather than on electrical or other processes which depend upon a direct application of electrical effects to the record sheet. Other details of a facsimile recorder employing an electrolytic process for producing marks are shown in U. S. Patent 2,391,765 granted to Maurice Artzt on December 26, 1945. A suitable recording solution is disclosed and claimed in the copending application of Myer Solomon, Serial No. 469,960, led December 23, 1942. This Solomon application is a division of the application now Patent No. 2,306,471 granted December 29, 1942.

The printer bar 16 together with the printer bar carrier means 18, both of this invention, will be now described in detail. The printer bar 16 of the invention is or may be in effect a composite structure comprising a resilient strip 52 to which is secured metallic strip 53. The strip 53 may be formed by flattening a wire. The strip 52 is preferably of metal. The ilattened wire is or may be joined to the strip by a series of spaced spot welds, or the T-shaped section may be formed from one piece. It will be noted that the entire electrode 16 is resilient in a direction normal to the plane of the strip 52 but by reason of its structure it is relatively rigid in a direction parallel to the strip 52. These are desirable characteristics for a recording electrode. The material of both the strip 52 and the flattened wire 53 is preferably selected with regard to physical properties such as resilience, and, with respect to the flattened wire, it must resist local heating and corrosion at the recording points. Suggested material for this purpose is a nickel-chromium alloy. Other embodiments of the invention to be discussed hereinafter include showings of a unitary or integral printer bar 16 having the genral physical shape of the printer bar of Fig. l.

The support for the printer bar 16 is, in accordance with the invention, a yielding membrane 56 upon which the strip 52 is cemented or otherwise secured in intimate contact therewith. This membrane is preferably free and unsupported over a portion of its area on its side opposite from the electrode. One way of achieving this result is indicated in Fig. 1 of the drawings wherein the membrane 56 is cemented or otherwise secured to the face of a supporting member 58 which is slotted as indicated by reference character 59, this slot being centered with respect to the flattened wire 53. While a slot 59 has been shown, it will be understood that the member 5S may merely be grooved or otherwise formed to provide relief in the supporting surface opposite to the printer bar 16.

In View of the resilient nature of the electrode 16 and the damping elect of the membrane 56 it is unnecessary, with the printer bar of this invention, as has been pointed out above, to mount the bar in any sort of hinged or springy mounting. In fact, such a mounting is not only unnecessary but is undesirable inasmuch as it may be set into vibration if the drum 12 operates at modern high recording speeds in the neighborhood of 1600 to 2000 R. P. M. In the illustrative example the member 58 is more or less rigidly secured to the previously mentioned machine parts 19 and 20 by suitable fastening means such as screws 61. Adjustment of the position of the electrode 16 with respect to the helix or helices and with respect to the drum 12 is provided by adjusting screws 62 the latter being engaged in tapped holes in the member 58.

The printer bar 16 is insulated from the supporting member 58 where the membrane 56 is formed of natural rubber or a synthetic product such as neoprene. An insulated terminal connection for the bar 16 is conveniently provided by a post 64 which is mounted within a bushing or collar 66 of insulating material. One end of the electrode 16 or a separate metallic piece 67 connected to it is fastened by suitable means such as a screw 68 to the post 64. Where the printer bar may be grounded in operation, an additional metallic piece 71 is secured as by a screw 72 to the'supporting member 58 and is in contact with the end of the electrode 16. In this latter case, the terminal post is not needed.

Fig. 3 of the drawings, which shows the electrode 16 and the membrane 56 in cross-section, indicates the space between the edge of the slot 59 and the strip 52 and in this region the membrane is in shear. This construction takes full advantage of the damping character of the membrane in shear. For example, the membrane may be selected so that a reading of to 60 is obtained on a Shore durometer when the material is tested.

Stated in other words, the relation of the width of the relief groove to the width of the strip 52 is important. The membrane 56 of rubber has its best damping effect in shearand this occurs between the edge of 52 and the edge of the groove. At present we use for 52 1A" and for the groove 3%". The ratio groove width 52 Width 1 and 2 ment of the invention in which the tension of the membrane in a direction parallel to the plane of the part of the printer bar corresponding to the strip `52 is adjustable. The printer bar 76 corresponds in physical characteristics to tlie printer bar 16 of Fig. 1, but is of unitary or integral construction comprising a flat portion 78 and a ridge 79 which serves to Contact the recording medium or paper 46. This printer bar 76 is cemented or otherwise intimately secured to a membrane 81 of natural rubber, neoprene or the like. This membrane is drawn around a supporting channel 82 and its ends are clamped in position against the top of the channel by a rigid strip 84 held in place by suitable fastening means such as screws 86. The channel 82 slidably receives a stretching member 88 within its groove, the position of the stretching member being made adjustable by suitable means such as adjusting screws 91.

The stretching member 88 is grooved as indicated at 93, this groove corresponding in function to the slot 59 shown in Fig. 1 of the drawings. As the screws 91 are turned down, the membrane 81 may be placed under increasing tension. With the arrangement of Fig. 4 the tension in the membrane may be increased by turning the adjusting screws 91. This latter eifect increases the effective stiness of the resilient support for the printer bar which is provided by the material in shear between the edgs of the flat portion 78 and the boundary of the groove 93.

The channel 82 may be supported as shown by Fig. 1 of the drawings in which case the pressure of the printer bar on the paper can be independent of the setting of the membrane tension adjusting screws 91. The bar 76 and channel 82 may be moved bodily with respect to the drum and the helix or helices thereon.

Figs. 6 and 7 of the drawings show a further embodiment of the invention involving another arrangement for adjusting the tension in the electrode supporting membrane. In this embodiment, the supporting member 101 is in the form of an elongated block having saw cuts 103 and 104 extending from opposite ends of the block in an overlapping relationship. While saw cuts have been referred to for the sake of convenience of description, it will be understood that the resulting slots may be produced in any known manner. The membrane 106 is or may be in the form of a hose or tube 108 which lits around the supporting member 101. The printer bar 109 is cemented as before or otherwise suitably secured to the membrane 106 and the block 101 is grooved as indicated at 111 to provide relief for the back surface of the membrane at and adjacent the printer bar. An f adjusting screw 114 is engaged in a tapped hole 116 in the bar 101 and extends into contact with one face of saw cut 103. By turning this screw so that it enters the block it will be seen that the saw cut 103 will be spread, thereby expanding the block and placing the tubular membrane 108 under tension. Another adjusting screw 118 is provided which is threadedly engaged in a tapped hole 119. A hole 121 freely accommodates the shank of this screw. It will be seen from the drawing that when the adjusting screw 118 is tightened the saw cut 104 will be expanded. But suitably setting the screws 114 and 118 a uniform tension may be provided in the tubular membrane 108.

As indicated above in connection with the supporting member 81, the block 101 may be secured in a recorder as shown in Fig. 1 of the drawings.

Having now described the invention, what is claimed and desired to be secured by the Letters Patent is the following:

1. In combination in facsimile apparatus, a rotary drum having a helical member supported thereon, an elongated printer bar arranged to be positioned in cooperative relationship to the drum and helical member so as continuously to bring said elements to bear upon each other, a recessed support element for said printer bar, a resilient strip spanning the recess in the support element for positioning the printer bar on the support element, the thickness of said strip being small compared with its width transversely of the bar, said resilient strip overlapping and being effectively supported by the support element at each side of the recess, the base of the printer bar being secured against the resilient strip, said printer bar being of a width less than the width of the recess so that a portion of said resilient strip is in shear, means to feet a record receiving strip between the drum and the printer bar, and means to hold the recessed support element in position to maintain contact between the printer bar and the helix.

2. The combination of claim 2 wherein said last named means provides for adjustment of the position of the recessed support element.

l 3 A printer bar and printer bar support for a facsimile recorder comprising an elongated flexible printer bar having a fiat body portion and a projecting recording edge, the width of said printer bar body portion being relatively great with respect to its depth whereby said bar is flexible in a plane normal to its width, a support for said bar comprising an elongated member having an elongated recess therein, a exible strip secured to said elongated member to cover said recess, and said printer bar being secured to said flexible strip 1n alignment with and substantially centered with respect to said recess.

4. The printer bar and printer bar supporting means of claim 3 wherein the width of said bar is substantially less than the width of said recess whereby a damping eifect is provided by the ilexible member between each edge of said bar and each edge of said recess.

5. In combination an elongated printer bar having a flat body portion and a projecting recording edge, the width of said printer bar body portion being relatively great with respect to its depth whereby said bar is 'flexible in a plane normal to its width, a support for said printer bai comprising a resilient elongated membrane, said bar being secured to said membrane, an elongated member havinga recess therein, said bar being positioned opposite said recess, and means slidably receiving said recessed member, said last named means having means for moving said recessed member outwardly whereby to tension said resilient supporting member.

6. combined printer bar and printer bar holder comprising a resilient member, a support for said member comprising an elongated block having a recess therein, an elongated printer bar carried by said resilient member opposite said recess, and means associated with said block to tension said resilient member, said printer bar having a at body portion and a projecting recording edge, the width of said body portion being relatively great with respect to its depth whereby said bar is flexible in a plane normal to its width.

7. -combined printer bar and printer bar holder comprising a tubular resilient member, a support for said tubular member comprising an elongated block having a recess therein, said tubular member surrounding. said block, an elongated printer bar carried by said resilient member opposite said recess, said printer bar having a ilat body portion and a projecting recording edge, the width of said body portion being relatively greatwith respect to its depth whereby said bar is ilexible 1n a plane normal to its width, and means in said block to tension said resilient member.

8. The combined printer bar and printer bar holder of claim 7, said recessed block having slots therein eX- tending substantially the length of said block, and means for expanding said block whereby to alter the tension in said resilient member.

9. A printer bar for a facsimile recorder comprising an elongated flexible bar having a at body portion and a projection ending in a recording edge thereon, the body portion of said bar being relatively wide, said projection being centered on said at body portion, the sui'n of the thickness of the body portion of said bar and said projecting being small as compared with the width o f said bar whereby said bar is relatively flexible in a direction parallel to the plane of said projection and is relatively rigid in a plane at right angles to the plane of said projection.

References Cited in the tile of this patent UNITED STATES PATENTS Number

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