US3190956A

US3190956A - Facsimile apparatus having a magnetically biased marking stylus

Info

Publication number: US3190956A
Application number: US838931A
Authority: US
Inventors: Vaccaro Angelo
Original assignee: Columbia Ribbon and Carbon Manufacturing Co Inc
Current assignee: Columbia Ribbon and Carbon Manufacturing Co Inc; International Business Machines Corp
Priority date: 1959-09-09
Filing date: 1959-09-09
Publication date: 1965-06-22
Anticipated expiration: 1982-06-22

Description

3,190,956 FACSIMILE APPARATUS HAVING A ncnnucALLY Busan mnu@ smus Filed spt. 9. 1959 June 22, `1965 A. vAccARa 4 shuts-sneer 1 mmYr 7// ////////////////////////////,Z www www .O Nh W n? NW mW VW I l l n N w wh Nw l n wm o M lllhi w um wh n.w\ -\J rf-,-m m\| uw I III l l o 5s Su Nm I. o 8mm QN @mm E@ l Inrnnw mM. mm m.. m, K um. -L hmmm n Mn mw .V f @u www T Il J II, f umm mw: Jmif um Q NN 4 l, l will l R IV l www.' I Jl .nl l hv. www. l mm. W .K U MMV hn \|.f| mm. a nu um mm nm I l M m w N@ @L S @LJ kga@ ATTORNEY June 22,` 1965 A. vAccAno `3,190,956

FACSIMILE APPARATUS HAVING A IASNETICALLY BIASED MARKING STYLUS A 'ITO RNEY June 22 196.5 A A. vAccARo 3,190,956

FACSIMILE APPARATUS HAVING' A MAGNETICALLY BIASED MARKING STYLUS Filed Sept. 9, 1959 4 Sheets-Sheet 3 AC. Ame

' 40 57 RECTIFIER] INVENTOR Wala Vacca/"0 BY l I Q i ATTORNEY( A. vAccufaoA June 22, 1965 FACSIMILE APPARATUS HAVING A MAGNETICALLY BIASED MARKING STYLUS Filed Sept. 9, 1959 4 Sheets-Sheet 4 IN VEN TOR.

Agde/0 Vacca/0 BY United States Patent() 3,190,956 FACSIMILE APPARATUS HAVING A MAGNETI- CALLY BIASED MARKING STYLUS Angelo Vaccaro, Port Washington, N.Y., assigner to 4Columbia Ribbon and Carbon Manufacturing Company, Inc., Glen Cove, N.Y., a corporation of New York Filed Sept. 9, 1959, Ser. No. 838,931 8 Claims. (Cl. 178-6.6)

The present invention relates to methods and apparatus for making facsimile copies of original subject matter such as pictures, drawings, photographs, typed and printed matter, etc., and more particularly to the making of a facsimile copy on a copy sheet by utilization of pressureresponsive transfer mediums such as carbon paper or like material and pressure-applying means such as a stylus.

According to the present invention, the apparatus employed involves suitable means for supporting in superposed position a copy sheet anda transfer sheet, Vsaid sheets being herein collectively called ycopy-producing material, and also means for supporting the stylus and operating mechanism therefor with means for providing relative movement between vthe respective supporting means so that the stylus may be progressively brought into operative relation with `the entire area of the ,copyproducing material by which thefacsimile is to be made.

The stylus and its operating mechanism to produce a facsimile copy are responsive to electrical variations derived from the subject matter of the original by photoelectrically scanning thelatter and converting the results of the scanning operation to electrical signals.

According to the broader aspects of this invention, the scanning of the original may be performed at a point remote from the facsimile-producing` apparatus and the signal maybe transmitted to the apparatus electrically.

When, as is preferable, the original is available at the facsimile-producing station, the` latter may be scanned on the same apparatus which` produces the facsimile copy.

To do this, ithas beenproposed heretofore to place the original sideby sidewith` the copy-producing material on a drum or cylinder so that `the original could be scanned by 'photoelectric rmeans and the copy-producing material separately traced or trackedby the stylus simultaneously while making a copy.

It has been discovered, however, that with the apparatus` of the present invention it is possible to superpose the original on the copy-producing material provided the original is not so thick or stiff as to prevent the marking `pressure applied by the stylus to be effective on the copy-producing material. By so superposing the original Patented June 22, 1965 the hectograph master sheet so that the image produced thereon will be in mirror reverse. If the copy-receiving sheet is to be used as a master sheet in a planographic duplicating machine of the olfset type or is merely to be used as a record, the transfer sheet is placed uppermost in the pile having its transfer surface adjacent the working surface face-down on the copy-receiving sheet. If the copy sheet is translucent, it may be placed above the face-up carbon sheet, in which case the subject matter may be read through the copy sheet.` If duplicate facsimile copies are required, several copy-receiving sheets and several transfer sheets are properly arranged in the pile.

One of the important features of the present invention is that the facsimile copies may be made by the methods and apparatus of this invention more rapidly than was heretofore possible. This has been accomplished by reducing to a minimum the `movements of the stylus between marking and nonmarking positions so that the stylus is instantly made effective to produce a mark upon receiving a signal requiring a mark to be made.

For this purpose, the present inventionprovides for maintaining the stylus in operative engagement with the copy-receiving sheet (and the original When the latter is superposed thereon) during the entire time that the stylus `is ,tracing the area of the copy sheet which is to receive the facsimile copy with a pressure which is insutiicient onthe copy-producing material the cost of the apparatus may be substantially reduced and the machine may be madersubstantially less Wide than when the original and the copy-producing material are supported side by side on a drum for instance. l

The superposing of the loriginal and the copy-producing material on a single support has the further advantage that When the facsimile copy is to be placed as an insert `on prepared material on the `copy sheet, the operation of locating the original with respect to the prepared material on the copy sheet is greatly facilitated both with regardY to time and effort, since the original may be applied to the` copy-receiving material as an applique.

It will be understood by those skilled in the art that the copy-receiving sheet `and the transfer medium may` to produce a mark on the copy sheet except `when a signal is received requiring a mark to be made at which time the pressure produced by the stylus on the copy-receiving material is increased to produce a mark. In this way the marking movement of the stylus is infinitesimal and instantaneous, permitting the rate of relative tracing movement between the stylus and the'copy-receiving material to be substantially increased over that which would be necessitated were the stylus taken out of contact with the copy-receiving material when no mark is to be` made during the making of a facsimile. `In addition to increasing the speed of the operation, the danger of chattering of the stylus incident to the impactwhich would be produced if the stylus Were taken olf and applied to the copy-receiving material during the making of a copy is obviated.

According to the present invention in its broader aspects, the stylus may be held in operative engagement with the copy-receiving material (and on the original if the latter is superposed on the copy-receiving material) by any suitable means so long as the pressure applied is insufficient to cause a mark to be made on the copy sheet when no mark is called for by the signal, but it has been found particularly advantageous and preferable `to cause the stylus to be held in such engagement magnetically when no mark is called for and by an increased magnetic force as a result of the electrical variations derived from the originalby increased pressure sufficient to cause a mark to be made on the copy sheet. In this Way it is possible and convenient tovary the pressure applied to the stylus according tothe Work at hand so that no mark is made on the copy sheet when no mark is called for and yet a mark of sufficient intensity is made When the electrical variations call for marks to be made.`

f in the broader aspects of this invention, the magnetic `force controlling the stylusmay be createdand controlled by any suitable means. For instance,` the stylus may under the influence of an electromagnet responsive to i the electrical Variations derived from the originalgto be be used as a hectograph master sheet for use in the spirit copied. However, it has been found `that substantially more faithful response of the stylus to such electrical variations results when the stylus itself` constitutes the :armature responsive to the magnetic force. This is particularly noticeable when, as pointed out above, the

3 stylus remains inoperative engagement with the copyproducing material during the entire time that the copy is being made because this arrangement avoids the necesysity .of using linkage means, spring biasing and damping means to operate and control the stylus.

In the form of this invention at present preferred, this is accomplished by making the stylus, or a substantial part thereof, magnetizable material, making the copylthe support for the copy-receiving material may be effected by holding the one stationary while the other travels, but, regardless of which one of -the supports travels across the other, the support for the stylus and a support for .the electromagnet are so interconnected that the pole lpiece of the electromagnet continuously remains oppositey the stylus.

In some forms of this invention, it is advantageous to arrange for the stylus and the electromagnet to be located on'the same side of Vthe copy-producing material and the support therefor. This may be done, While retaining most of the advantages of the arrangement described above where the electromagnet is on one `side ofthe support and the stylus is on the otherside, by arranging 'for the stylus and/or magnetic means inside the support for the copy-receiving material to be permanently magnetized so that the stylus is held in nonmarking engagement with the copy-receiving material by the force of the permanent magnet while the force to apply marking `pressure to the stylus is supplied by an electromagnet responsive to signal variations located adjacent the stylus and outside the copy-receiving support. Vln this aspect Aof the invention, a permanent magnet may be positioned under the support in position to attract the stylus.

, -`In another embodiment of this invention, the permanent magnet may be capable of applying sufficient torce to cause a mark to be made on the copy-receiving sheet by the stylus.

insuiiicient to make a mark and yet does not have the copy-producing material. Alternatively, the stylus may be permanently magnetized and the support for the copyreceiving material may be made of magnetizable material so that the 'stylus is held against the copy-producing material with a force insuiicient to make a mark. In this Vcase, the electromagnet, which is responsive to signal variations, has a pole piece having the same polarity as the permanent magnet of the stylus carrier so that when a mark is called for the repelling effect of the linx will force the stylus toward the copy-producing material with force suiiici'ent tomake aV mark, but'upon response to a non=marking -signal the repulsive action of the electromagnet would cease.

Other features and advantages will hereinafter appear.

In the drawings:

FIGURE 1 is a plan view of one embodiment of the apparatus of the present invention. 1

FIG. -2 is a front view thereof, partly in'section.v

FIG. 3 is a vertical section taken on the line 3--3 of FIG. 1.

FIG. 4 is an end view of the machine looking'in the y Adirection of the arrows 4 4 of FIG. 2.

AlFIGr. 5 is a` diagrammatic representation of the driving mechanism for driving the scanning means, stylus and stylus-operating means ofthe present invention.

ln this case, the electromagnet, whenA kenergized bya signal calling for no mark, Will counteract 4the force of the permanent magnet so that it is then FG. 6 is a diagrammatic representation of the interconnection of the various elements of the present invention.

FlG. 7 is a diagrammatic View of theY magnetic ux path of the embodiment of the present invention disclosed in FlGS. 1 6. v

FIG. 7a and FIG. 7b are diagrammatic representations of other methods according to the present invention of magnetically controlling the operation of the stylus.

PEG. 8 is a detail of a releasable locking mechanism for the means for feeding the scanner and marking stylus.

FIG. 9 is a diagrammatic view indicating the light path to and from the original, and also showing a plurality of copy and transfer sheets superposed on the supporting drum. Y

FG. lt) is a schematic diagram of the electrical ,system for converting the light reflected from an original to electrical variations for energizing the electromagnet which operates the stylus.

Referring to FiGS. l to l0 of the drawings, particularly FlG. 6 in which the apparatus of the present invention is illustrated schematically, a piece of sheet material, herein called the original 3d from which a facsimile copy is to berrnade, and which has subject matter such as a picture, diagram, etc. which may consistof or include Written, typewritten or printed matter, is mounted on a suitable support such as a rotatable drum 3l. p

Means for scanning the original comprises a lens 32, a restricted aperture 33, Vand a photocell 34. As the drum 3l rotates, the photocell 34, traveling laterally along the drum by means hereinafter described, scans the original on the drum along a helical line whose'width is such that the entire surfaceV of the original to be copied is sensed. The varying amount of retiected light, from the lighter background and the darker image-portions of the original, received by the photocell causes electrical variations to be derived from the original through the response of the photocell to the light. Light of substantially constant intensity is caused to impinge upon the original 30 `from a lamp 35 in a concentrated beam directed by alens 36 to the spot on'the original being scannedby the photocell.

The signal from the. photocell having electrical variations is fed to an ampliiier' which, in the form of the Vinvention herein disclosed, is a band 'pass A.C. amplier.

Because the signal from the photocell is DC. and hence is Vnot as readily amplified as an AC. signal, the present invention provides for converting the signal to A C. While .this may be done by using an A.C. carrier frequency with the DC. signal .superposed thereon, the present invention employs a motor 3S and a toothed wheel chopper 39 rotated thereby interposed in the light beam between the-photocell and the original to cause the normal D.C. signal to have a selected frequency depending on the characteristics of the chopper 39. The signal `from the/LQ amplier is fed through a rectifier 49 (preferably full-wave) 'and then fed to a DC. amplier 41. The signal current from the amplilier 4l varies the amount of magnetic lluX emitted from a stylus-operating electromagnet i2 by reason of being fed into a coil 43 thereof.

Mounted adjacent the periphery of the drum is a stylus d@ having a small point i5 and a lever. 46 which is .pivoted at one endas at 47 for movement toward and away from the drum. 1

According tovthe present invention, the facsimile is produced by pressure applied to copy-producing material so that the original is uppermost and the copy-producing material 4S is beneath it, thereby permitting the length of 'the drum to be virtually reduced by half. The original and the copy-producing material are offset either laterally along the drum or around the drum a slight amount so as to avoid the stylus interfering with the light reflected from the original passing to the photocell.

According to the present invention, the sylus 44 itself forms the `armature of theelectromagnet 42, and for this purpose the `stylus lever 46, or at least a suiicient portion of it, is made` of magnetizable material, suchas soft iron, and the electromagnet 42 is placed in such position relative yto the` stylus that when the electromagnet is `energized the stylus point 45 will be forced toward the drum and against the original and the copy-producing material carried thereby, the pressure applied by the stylus depending upon the degree of excitation of the electromagnet.

The elements in circuitry controlling the electromagnet 42 are adjustable` so that when the photocell 34 senses the background area on the original, the stylus point 45 is pressed against the original and copy-producing material so lightly that no mark is` transferred from the transfer sheet 5G to the copy sheetg49, but when an image portion of the original is sensed the stylus is attracted toward the drum with a force sufficient to cause a mark to be made on the copy sheet by the` transfer sheet. By having the stylus normally engage with the original and copy-producing material, the movement required of the stylus to make a mark is virtually imperceptible and instantaneous upon the receipt` of a signal calling for a mounted at opposite ends on ball bearings S1 secured in stationary hubstSZ. The hubs are secured on vertical side plates 53 mounted on a base 54. In order to rotate the drum, a gear 55 fastened 'thereto meshes with a gear 56 which is fast on a shaft57 having `a pulley 58 driven by a belt 59. As diagrammatically illustrated in FlG. 5 the belt 59 may be driven by a `variable speed device such stant speed motor and a variable speed transmission.

Extending between the vertical side plates 53 and rotatably mounted therein is a feed screw 60 which is rotated (FlG. 5) by a gear train 61 having gears 61a, 61h 61e and 6M with the gear 61a being fast on the shaft `57 and the gear 6M beingfast on the feed screw 6d.

The feed screw causes axial movement of a carriage 62 on which'the photocell` 34 and stylus 44 are mounted, by means of a split feed nut 63 secured to the support 62 and engaging the feed screw. The carriage 62 is supported for traveling movement on a rod 64 connected between the two side plates fili-which passes through a bearing sleeve 65 connected to the carriage 62 and also by a wheel or roller 66 secured to a depending plate 67 of the carriage 62 riding on a rail 68 fastened between the side plates 53.

The carriage 62 includes a bracket 69,`such as shown in FIGS.` 2 and 3, on which is mounted the light bulb and a light tube 7@ having the lens 36 therein to throw a bright spot of light on the drum. Also mounted on the bracket 69 is a light tube 71 having a lens 32 therein, and the small aperture 33 (which may be on the order of one-thousandth of an inch in diameter) formed in a cover 72. Positioned above the tube `71 in alignment with thelight passing through the aperture 33 is the photocell 34. A box '73 substantially encloses the photocell to prevent stray light from affecting it. i

Mounted in back of the vertical plate 69 is the motor 3d which carries and drives the light chopping wheel 39 withthe peripheral toothed portion of the wheel being positioned to interrupt the light through the aperture 33.

While the stylus 44 may be mounted to hang vertically `as a variable speed motor 59a or alternatively by a coni 5 if desired as indicated in FIGS. 7a and 7b, in the specific embodiment of the invention shown in FIGS. 1 to 6, it is mounted to extend horizontally on the carriage 62 to operate adjacent the point on the original being scanned. The stylus is pivotally mounted at 47 on an arm 74 secured by screws 75 to the verticalplate 69 and projecting outwardly therefrom. At its other end the arm 74 has a downwardly depending ear 76 to which is piv- `otally connected as at 47, a lever 46 of the stylus 44.

The lever 46 is formed in whole or in part of magnetizable material, such as soft iron, so that it will be attracted by the electromagnet 42.

It will thus be understood that as the drum revolves, the `carriage 62 with the photocell 34 and the stylus 44 move transversely thereof to scan and trace the original and copy-producing material respectively in a helical line. The pitch of the helical line is determined by the pitch of the threads of the feed screw 60 and its speed relative to the drum. Thus, for example, if the feed screw has 100 threads per inch, and rotates at one-quarter the speed of the drum the spacing between turns theoretically would be one-hundredth of an inch. However, by having the beam of light reflected to the photocell original from an area one-hundredth of an inch Wide and the point 45 of the stylus of asize which produces a mark on the facsimile copy sheet of approximately one-hundredth of an inch, substantially the entire surface of the original and copy-producing material will be scanned and traced respectively. t

In this embodiment of the invention, the electromagnet 42 which actuates the stylus 44 is positioned within the drum 31 so as to have magnetic flux lines generated thereby pass through the drum 31, the copy-producing material and the original. While it is contemplated that the electromagnet could extend for a full length of the drumand hence be stationary, the embodiment disclosed enables the use of a smaller electromagnet by moving it in the drum transversely thereof synchronously with the carriage 62 and stylus 44. The electromagnet 42 includes a magnetic core 77 about which is wrapped the coil 43, which when energized magnetizes the core 77 to attract the stylus 44. The electromagnet 42 is fastened on theinverted U-shaped member forming a carriage ,78 having bushings 79 through which pass guide rods 80 secured to and extending between the hubs 52, thereby supporting the electromagnet 42 for transverse, sliding movement. Y

To correlate movement of the stylus 44 and the electromagnet 42, there is connected at one end of the stylus carriage 62 a length 81 of flexible wire as by a clamping screw 82. The wire extends over pulleys 83a, 83]), 83o and 83a.' through the drum 31 (see FIG. 5) and has `its'other end connected to the electromagnet carriage 78.

For movement in the reverse direction, a second length S4 of flexible wire is clamped to the carriage 62 by screws 85 and is trained over pulleys 86a, S611, 86e and 86d through the drum 31 and has its other end connected to the carriage 78. The

wires

81 and 84 pass through apertures 87 in the hubs 52 `to `reach the carriage 78. It will thus be appreciated that movement of the `stylus car- Iriage 62 will cause similar movement of the electromagnet carriage 78. i i

In order to facilitate positioning of the carriage 62 on the feed screw 6), the feed nut 63 as shown has two separable half sections 88a and 88h slidable in a slotted guide plate S9 mounted on the carriage 62 and movable to engage and disengage thefeed screw. `Each half 88a and 88bkhas a cam pin 90 engaging a cam slot 91 in a disk 92 (see FIG. 8) secured to a shaft 93 which rotates within a bushing 94 that is fast` on the` depending plate 67. The other yend of the shaft 93 has a handle 95 secured thereto to rotate the circular plate 92 and cause the pins to separate the two feed nut selections 58a and 88b to release the threaded engagement thereof with the feed screw 60 or bring them together on the feed screw after .the carriage :62 has been adjusted Ato the desiredposition.

As shown .in FIG. 9, if it is desired toproduce 'directly more than 'one facsimile copy at a time, the copy-produc ing material 48 may `consist of one or more additional interleaved carbon sheets`98 and copy sheets`99 on which the reproductions are iproduced. -It will 'be appreciated that vthe number .of facsimile Vcopies which can Abe made .simultaneouslydepends upon the force fof the attraction -between the electromagnet 42 andthe stylus 44 that `presses -the stylus Vagainst the reproduction sheet, `the thickness of the copy-producing material, vand 'the character of the ,transferable carbon coating on thel carbon paper sheets.

FIG. 9 `a'lso'shows schematically the Vrays 196 from 'the light source limpinging on an Yincrement of the original adjacent the stylus ibut transversely spaced therefrom to ,permit the light reflected 'rays97 from the increment -topass bythe stylus 44 to the photocell.

Shown in FIG. 10 is a schematicelectrical diagram of the scanning means and the inscribing means including the photocell 34, the A.'C. amplitier37, the rectifier 40 andthe DC. amplifier 41. The photocell 34 is connected between the positive side of a D.C. supply 1% and ground so that there is conduction therethrough when the photocell `is Vsensing white or background color, while a darker color, such as black ink, renders the photocell substan- 'tially non-conducting. Thetoo'thed chopper wheel 39 causes vthe photocell to produce a'pulsating signal which is fed through a condenser 101 (having low resistance to the'pulsating frequency) to a gri'd1tl2 of the iirst stage of a double stage amplifying electron tube V103. The signal is amplified from the first stage of tube 103 to the grid 104 of the second stage of tube 193and successively amplified* and lpassed through condenser 165 to the grid 106 of tube 1117, then through condenser 10S to the iirst stage grid 109 of a ldouble stage tube 11i). The components vof the AgC. .amplier are considered to be well known and the sole function thereof is to amplify the pulsating DC. signal `from the photocell 34.

The amplified .signal from the plate 111 o'f thefirst stage of tube 110 is Jconductedto'a primary winding 112 of an isolated .transformer 113 in the rectifier 40. This latter includes a 'secondarywinding 1-14 which is center tapped as at 115 while the winding ends are connected 'through rectifiers 1,16 Vto an inductive Vcapacitive lter circuit, `generally `indicated lby vthe reference numeral 117, to produce a voltage of approximately volts between thelpoint 1.18 and ground. This voltage may be adjusted by a variable Yresistance `119 connected between the rst stage plate and second stage grid 104 of tube 103 in the second stage ofthe tube.

Connectedbetween the vpoint 118 and the grid 120 of `the second stage of tube 110 -is a line containing a resistlance 121 and a variable resistance 122 connected to the negative side of the DC. supply. This line supplies a voltage at the junction 118 which is positive with respect to the voltage at the junction 118 and its value is less than 240 volts so that even when it is subtracted from the 20 volts, there Vis suiiicient plus voltage remaining Vto cause ythe second stage of tube to be fully conducting whenyever the vsignal 'has a value of 20 volts. When tli photocell senses black, i.e. an image portion of the original, there is no plus voltage at junction `118 while the voltage on the grid 120 is relatively negative, derived solely from p, the negative LDC. supply through the resistors 121 and122 the second stage of tube 110 to render it conducting, there is a relatively large voltage drop across the resistance 124 by reason of the current flow through the tube, while when the tube is non-conductive (as when the photocell senses black) there is a smaller voltage drop across the resistance 124. Thus when the photocell senses black the positive voltage to ground in the lead V125 is higher than when the photocell senses white The voltage in line 125 is impressed (after passing through resistance 126) on the control grids 127 and 128 of the tubes 129 and 130. With the higher voltage in lead 125, the tubes 129 and 130 are rendered conducting causing current ow through the electromagnet 42 which causes the stylusvto be attracted against the copy-producing material with sulicient force to impress a mark on the copy sheet. When the voltage in the lead 125 is at its lower value, as when the photocell senses white, and the second stage of tube 110 is conducting, there is insufiicient positive voltage on the control grids of tubes 129 and 130 so that they do not conduct suflicient current to render the electromagnet '42 effective to produce a mark on the copy.

it will accordingly be understood that when the photocell senses a black increment, its signal is amplied by the A.C. amplifier, rectified in the rectier 40 and causes a high positive voltage in the lead 125, by reason of the second stage of tube 110 being non-conducting. This voltage when impressed on the control grids of the tubes 129 and 13@ causes conduction therethrough and since their output is connected to the positive D.C. supply through the electromagnet 42, suiiicient current passes in the electromagnet to cause 'the stylus to be attracted with a force suiiicient t-o cause a mark on the facsimile copy. When the photocell senses a white increment, the signal from the photocell is amplified causing the second stage of tube 110 to be conducting which decreases the positive voltage in the lead 125 and hence on the grids of tubes 129 and 130 to a value which shuts off the current through the electromagnet 42.

It has been found, in carrying out the present invention, that although the residual magnetism of -the electromagnet '42 and/ or the weight of the stylus may under `most favorable conditions be sutiicientto maintain the stylus against the copy-,producing material at all times, particularly whenthe photocell is sensing background or white increments, more `satisfactory results can be obtained by applying a greater force yet one which is insufficient to produce a mark. To do this, the present invention, in its form at present preferred, provides for employing the stylus-operating electromagnet 42. It has been found that by passing a minimum positive value of current through the electromagnet 42 the value of the current canV be adjusted to maintain the stylus forced against the copy-producing material with a pressure which is insuiiicient to produce a mark on the facsimile copy, yet which is firm enough to hold the stylus from vibrating or chattering.

This is accomplished in the -form shown by impressing on the control grids of the tubes 129'and 130 a bias voltage which has la value that renders the'tubes conducting for only the adjusted value of current at all times, it being, of course, effective when the photocell senses a background or white increment. Thus there is provided a connection to the control 'grids 127 and 128 by a lead 131 through a resistance 132 and a variable resistance 133 to the negative side of the D.C. supply tothe control grid. It will be appreciated that by -adjusting this resistance 133 with relation to the Voltage when the photocell Vis sens- -ing white at the connection, the minimum constant value of current through the electromagnet 42 may be applied and this can determine the amount of force with which the stylus is pressed Vagainst the copy-producing material and yet not mark the `facsimile copy.

In FIG. 7 is shown the lines of flux from the electromagnet 42 which pass through the rods 80, the hub 52, the side plates 53, the rods 64, the carriage 62, the stylus lever 46, through the original and the copy-producing material 48 and the drum 31 to complete its path. All parts in the path except the original 30, .and the copyproducing material 48 are formed of magnetizahle material.

To carry the current to the electromagnet 42 and yet permit Ithe latter to ltravel back and forth relative to the drum, .the present invention provides a half-round rod 140 having a pair lof contact strips 141 thereon located under the electromagnet carriage 78 to `be engaged by a pair of contact pins 142 connected by wires -to the energized coil 43.

In FIG. 7a, the magnetic means for controlling the stylus @to cause marks to be made on the copy-receiving sheet in response .to Variations in the signal may be a permanent Amagnet 42alocated within the drum 31 opposite the stylus and traversing the drum with the stylus, a-s in FG. 7. The stylus 46 is made of magnetizable material and is attracted with suiiicient force 'to the permanent magnet 42a so as to be capable of making a mark. However, an electromagnet 142 travelingr with the stylus 46 is positioned to con-trol the stylus so as to normally, that is when no mark is to be made, counteract the force of the permanent magnet 42a and reduce the pressure of the stylus on nthe copy-receiving material without removing the stylus therefrom. When the flux in the -electromagnet is reduced in response to a varia-tion in the signal calling for a mark to be made, the permanent magnet pulls the stylus toward the copy-receiving material with sufcient force `to make a mark.

As stated above, the stylus carrier may be permanently magne-tized so as to be attracted to the drum 31a of magnetizable material with suicient force to hold the stylus against the copy-receiving material but with insufficient force to cause a mark to be ymade on Ithe copy sheet. This arrangement is illustrated in FIG. 7b in which the stylus carrier 46a is a permanent magnet having one pole piece located at the endat which the stylus 45 is mounted in position to engage the drum. 'For purposes of explanation, it its assumed .that the stylus carrier 46a has a north pole adjacent the stylus and a south pole adjacent its pivot point. The meansto control the marking or non-marking of the copy sheet comprises an electromagnet V242 which has its `pole piece located adjacent .the pole of the stylus carrier at which the stylus is mounted. The electromagnet 242 is so wound that it presen-ts a north pole adjacent the north pole of the stylus carrier 46a. When the electromagnet 242 is energized in response to a variation in the signal calling for a mark to be made, it being confronted with a permanent magnet of like polarity on the stylus carrier 46a, the ux from the electromagnet 242 causes the stylus carrier `to be forced away from the eiectromagnet toward the drum, and thus cau-ses marking pressure 4to be applied to the copy-producing material. When no marking signal is received by the eiectromagnet 242, the permanent magnet stylus carrier 42a holds the stylus against the copyreceiving material with` insufficient pressure lto make a mark.

Variations and modifications may be made within the scope of the claims and portions of `the improvements maybe used without others.

I claim:

1. Apparatus for producing a facsimile copy of an original from variations in electrical signals derived from areas of different light reflective values in the original, comprising non-magnetizable means for supporting copyproducing material including a copy sheet; a stylus for producing marks on said copy sheet; means for relatively moving the stylus and the support-to scan said copy-producingmaterial; Iand electromagnetic means for continuously pressing the stylus again-st said copy-producing material on the support with either a positive marking pressure or a positive non-marking pressure depending on the variations in said signals.

2. Apparatus for producing a facsimile copy of an original from varia-tions in electrical signals derived from areas of dilerent light reflective values in .the original, comprising non-magnetizable means for lsupporting copyproducing material including a copy sheet; a stylus for producing marks on said copy sheet and having at least a portion of magnetizable material mounted for movement toward the support; means for relatively moving the stylus and the support to scan said copy-producing material; and electromagnetic means positioned behind the support and in close proximity thereto for transforming the electr-ical signals into magnetic ux lines of suflicient density to cause the stylus to be attracted against the support through the copy-producing material with suiicient force .to mark the copy sheet when the original has a predetermined value range, and means for supplying :a constant ux to lcause the stylus to be continuously attracted against the Asupport through the copy-producing material with insutiicient force to mark the copy sheet when the signal has a lower predetermined value range.

3. Apparatus for producing a facsimile copy of an original from variations in electrical signals derived from areas yof difierent light reilective values in the original, comprising non-magnetizable means for supporting copyproducing material including a 4copy sheet; a stylus for producing marks on said copy sheet and having at least a portion of magnetizable material mounted for movement ltoward the support; means for relatively moving the stylus and the support to scan said copy-producing material; and electromagnetic means compri-sing a coil wound about a magnetizable pole loca-ted adjacent and positioned behind the support for transforming the electrical signals into magnetic uX lines of sufticient density to cause the stylus to he electromagnetically attracted tow-ard the support and against the copy-producing material `with sufficient force to mark the copy sheet when the signal has a predetermined value range and to be electromagnetically attracted with insuflicient force to mark the copy sheet when the signal has a lower predetermined value range.

4. Apparatus for producing a facsimile copy of an original from variations in electrical signals derived from areas of different light reflective values in the original, comprising non-magnetizable means for supporting copyproducing material including a copy sheet; a stylus for producing marks on said copy -sheet and having at least a portion of magnetizable material mounted for movement toward the support; stylus operating means positioned behind the support for .transforming the electrical signals into magnetic flux lines of sutlcient density to cau-se the stylus to be :attracted toward the support and against the copy-producing material with sufiicient force to `mark the copy sheet when the original has a predetermined value range, and means for supplying a constant flux t-o cause the stylus to be continuously attracted against the lsupport through-the copy-producing material with insuiiicient force to mark the copy sheet when the signal has a lower predetermined value range;.and means for causing traveling movement between the support and the stylus and stylus operating means as a uni-t whereby the stylus .scans the copy-producing material.

5. Apparatus for producing a facsimile copy of an original from variations in electrical signals derived from areas of different light reflective values in the original, comprising nori-magnetizable means for supporting the original and copy-producing material including a copy sheet in superposed position with the original exposed; a stylus for producing marks on said copy sheet and having at least a portion of magnetizable material mounted for movement toward the support; a photoceil in fron-t of the support to scan the original; means for causing relative movement between the support and the sylus and photocell to scan the original and said copy-producing material; and electromagnetic means comprising a coil Wound about a magnetizable pole being located adjacent and positioned 'behind the support for transforming the electrical signals into magnetic iiux lines of suiiicient density to cause the stylus -to be attracted toward the support and against 'the copy-producing material With sufficient force to mark the copy A'sheet when the signal has a predetermined value, and means for supplying a constan-t flux to cause the stylus to be continuously attracted against the support through the copy-producing material with insufficient 'force to mark the copy sheet when the lsignal has a lower predetermined value, said coil and magnetic pole being mounted in xed position relative to the position of the stylus and pho'tocell.

6. An apparatus for producing :a facsimile copy of an original comprising a support for the original, a fphotocell; means yincluding the photocell for producing la signal indicative of the amount of light reflected from a small `increment of lthe original; means for relatively moving the support and the pliotocell to cause the photocell to traverse the original to scan it; a marking stylus adapted to mark pressure sensitive copy-producing material; means for lrelatively moving the stylus and the material; electromagnetic means controlled by the signal for magnetically holding the stylus against the copyproducing material as it traverses the same with insuiificient pressure to mark the sheet'when the signal is of one value and for increasing the pressure -suilieiently to mark the sheet when the signal is of a different value; and means in the signal means for adjusting the value of the signal with respect to the light retlective value of the original whereby the diterent value signal which causes marking may be adjusted relative tothe amount of light rellected as scannedby the photocell.

7. An apparatus for producing a facsimile copy of an original comprising a support for Vthe original, la photocell; means including thephotocellV for producing a signal indicative of the amount of light reflected from a small increment of the original; `means Vfor relatively moving the support and the photocell to cause 'the `photocell to traverse the original to sean it; a ymarking stylus adapted to mark pressure sensitive copy-producing material; means for relatively moving the stylus and the material; electromagnetic means controlled by the signal for magnetically holding the stylus against the copy- Vproducing material as it traverses the same with insuicient pressure to Amark the sheet when the signal is of one value and for increasing the pressure sufficiently to mark the sheet when the signal is of a different value; and means in the signal means for adjusting the pressure with which the stylus is held against the copy-producing .material in .non-marking engagement thereto.

8. lAn apparatus for :producing a facsimile copy of Van original comprising a support for 'the original, a photocell; means including the .photocell for producing a signal indicative of the amount :of light reected from a small increment of the original; means for relatively moving the support and the photocell to cause the photocell to traverse :the original to scan i't; a marking stylus adapted to mark` pressure sensitive copy-producing material; means for relatively moving Ithe stylus and the material; electromagnetic .means controlled by the signal for magnetically vholding the ystylus against the copy-producing material as it traverses the same with insufficient pressure to mark the sheet when the -signaltis or" one value and for increasing ythe pressure sufficiently to mark the sheet when the signal Vis of Ia different value; means in the signal means for adjusting the pressure with which the stylus is held against the copy-.producing material in non-marking engagement thereto; and means in the signal means for adjusting the value of the signal with respect yto the light reflective value of the original whereby the different value signal which causes marking may -be adjusted lrela- -tive to :the amount of light reilected as scanned by the photocell. t

References Cited Vby the Examiner UNITED STATES PATENTS .DAVD ,G' REDNBAUGH,Y Primary Examiner.

NEWTON -L. LOVEWELL, E. JAMES SAX, ROY

LAKE, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,190,956 June 22, 1965 Angelo Vaccaro It is hereby certified that error appears in the above numbered patent reqiiring correction and that the said Letters Patent should read as oorrectedbelow.

Column 1,

lines

59 and 60 for "prepared", each occurrence read preprepared column 2, line 57, for "applied to" read applied by column 3, line 8, before "magnetizable" insert of line 15, for "electromagnetic" read electromagnet line 50, for "have" read leave column 5, line 6, for "sylus" read stylus column 6, line 43, for "the" read an Signed and sealed this 30th day of November 1965.

(SEAL) Auest:

ERNEST W. SWIDER EDWARD J. BRENNER Allcsting Ufficer Commissioner of Patents

Claims

1. APPARATUS FOR PRODUCING A FACSIMILE COPY OF AN ORIGINAL FROM VARIATIONS IN ELECTRICAL SIGNAL DERIVED FROM AREAS OF DIFFERENT LIGHT REFLECTIVE VALUES IN THE ORIGINAL, COMPRISING NON-MAGNETIZABLE MEANS FOR SUPPORTING COPYPRODUCING MATERIAL INCLUDING A COPY SHEET; A STYLUS FOR PRODUCING MARKS ON SAID COPY SHEET; MEANS FOR RELATIVELY MOVING THE STYLUS AND THE SUPPORT TO SCAN SAID COPY-PRODUCING MATERIAL; AND ELECTROMAGNETIC MEANS FOR CONTINUOUSLY PRESSING THE STYLUS AGAINST SAID COPY-PRODUCING MATERIAL ON THE SUPPORT WITH EITHER A POSITIVE MARKING PRESSURE OR A POSITIVE NON-MARKING PRESSURE DEPENDING ON THE VARIATIONS IN SAID SIGNALS.