US3102472A - Rotary printing press for apertured continuous metal strip - Google Patents

Description

p 3, 1963 R. J. KIECKHEFER, JR 3,102,472

ROTARY PRINTING PRESS FOR APERTURED CONTINOUS METAL STRIP Filed May 22, 1961 I 3 Sheets-Sheet 1 w m a g z 2% a m o g o 5' E I (Q K1 n' Q a E 0 6 E1 N E -Q- m N N COOLER mJAw-rfpqj V 51% IKz'eckhafsmJiz REWIND fig? p 3, 1953 R. J. KIECKHEFER, JR 3,102,472

ROTARY PRINTING PRESS FOR APERTURED CONTINOUS METAL STRIP 3 Sheets-Sheet Filed May 22, 1961 mdp-vh d aberZ IK'I hgfar, J5.

Sept- 3, 1963 R. J. KIECKHEFER, JR 3,102,472

ROTARY PRINTING PRESS FOR APERTURED CONTINOUS METAL STRIP Filed May 22, 1961 3 Sheets-Sheet 3 a I Swmiv.

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Y Jfieakh ezgJin A? [W N I 17% United States Patent 3,102,472 ROTARY PRINTING PRESS FOR APERTURED CONTINUOUS WTAL STRW Robert J. Kieckheter, Jr., Barrington, Ill., assignor to Litho-Strip Corporation, a corporation of Illinois Filed May 22,1961, Ser. No. 111,784,

8 Claims. (Cl. 101-228) This invention relates to apparatus for printing and decorating metal and similar substantially stiff material in continuous strip form, and refers more particularly to means for so controlling the rotation of the impression roller or rollers in such apparatus that the successive impressions made thereby are all in register with apertures in the material located at regularly spaced intervals along its length.

Printing and lithographing metal and similar substantially stiff materials in continuous strip for-m presents serious problems not encountered in the web printing of relatively supple materials such as paper, metal foil and fabric. A major problem is the synchronization of the rotation of the impression roller, carrying the image to be reproduced, with the lengthwise motion of the strip, so that the successive impressions made by the impression roller are at uniformly spaced predetermined intervals along the strip.

While the term register is usually employed inthe graphic arts to denote the correct relationship to one another of two or more successively made impressions that occupy a single imprint area on a web or sheet being imprinted, it will be seen that the term is applicable also, at least in an analogous sense, to designate the correct relationship to one another of two or more impressions occupying different but adjacent imprint areas along the length or across the width of a strip or web, and the term register is sometimes used herein in that sense. More specifically, the present invention is concerned with the problem of obtaining register (in the specialized meaning thereof) lengthwise along the strip or web.

Since a strip which is printed or decorated with length wise adjacent impressions that are in register with one another is usually intended to be cut and formed into containers or other articles of manufacture after the printing or decorating operation is performed thereon,

the attainment of such register to a high degree of perfection is of the utmost importance in order to insure that the impressions appear in exactly the desired locations on the finished articles when the same are formed from the strip by automatic machinery.

Patent No. 2,890,653, issued June 16, 1959 to F. J. Kinzelman, discusses the problems encountered in obtaining lengthwise register in the printing of metal and similar stiifmaterial in continuous strip form and discloses a a method and means for achieving such register. the apparatus of the Kinzelman patent has proven to be generally successful, it is not capable of satisfactorily accomplishing one form of register printing which is of substantial commercial importance. In many cases printed, decorated or lithographed metal containers and other articles of various types are provided with an aperture of some sort, and the impression on the finished article must be in register with this aperture. While it is possible to form the aperture :by a punching operation accomplished during formation of the article, using the printed impressions on the strip as a guide to indexing the material through the forming machine, the present While invention contemplates that a more efficient and expediapertures in the strip during the article forming operation, as a means of indexing the strip through the forming machine. With the apparatus of the Kinzelman patent it was possible to print successive impressions along the length of the strip in a desired relationship to one another, but it was at best very difiicult to imprint them in register with preformed apertures in the strip.

Thus it is a general object of the present invention to provide apparatus for printing and decorating metal and similar substantially stiff material in strip for-m, wherein the rotation of the impression roller or rollers is so controlled that the impressions made thereby are in length- Wise register with apertures located at regularly spaced intervals lengthwise along the strip.

More specifically, it is an object of this invention to provide apparatus of the character described, having an impression roller by which successive impressions are imprinted along the length of a continuous strip of metal or similar material and which is mounted at a fixed location along a defined path of lengthwise strip travel for rotation in engagement with the strip, and having means whereby the impression roller is in effect geared to the strip to insure that the successive impressions which it makes will he in lengthwise register with apertures spaced at regular intervals along the length of the strip, and wherein edge portions of the strip around the apertures are utilized as an element of such gearing.

Another specific object of this invention is to provide, in apparatus for printing and decorating metal in con tinuous strip form having apertures at regular interval along its length, a monitor roller havingspur or cog members that are adapted to meshingly engage in the apertures in the strip, and having a geared or similar transmission means drivingly connecting the monitor roller with an impression roller by which impressions are made on the strip, which transmission means constrains the impression roller to rotate in synchronism with the monitor roller and at a circumferential speed substantially equal to that of the monitor roller, to assure that each impression printed on the strip will be in lengthwise register with an aperture therein.

Another object of this invention is to provide means (for reducing to a negligible value the load forces which the strip and the spurs or cog members on the monitor roller present to one another to thus prevent any possibility of the cog members deforming the strip at the edge portions of theapertures therein, and to insure that the monitor roller will at all times have smooth meshing engagement with the strip.

In the apparatus of the aforesaid Kinzehnan patent the backup roller was used as a monitor roller for synchronizing the circumferential speed of the impression roller With the local linear speed ofthat portion of the strip lacing engaged by the impression roller. With the objective of preventing slippage between the strip and the backup roller, the strip was wrapped partway around the circumference of the backup roller so as to undergo a change of direction in its path of travel at the backup roller. .In spite of the wrap of the strip about the backup roller, slippage could and did occur from time to time. A more serious disadvantage arose from the fact that the backup roller engaged the inner radius of the wrapped portion of the strip while the impression roller engaged its outer radius, so that the circumferential speeds of said rollers had to ditfer slightly, by an amount pro portional to the thickness of the strip material, if register was to be accurately maintained. To correct for possible variations in strip thickness and other effects, the apparatus of the Kinzelman patent included a long term register control which effected changes in the speed relationship between the backup and impression rollers.

It will be apparent from what has been said above that the present invention overcomes the disadvantages in the apparatus of the Kinzelman patent and has, as another of its objects, the provision in apparatus of the character described, of means affording a positive driving connection between the strip and the monitor roller whereby slippage between them is prevented.

It will also be apparent that it is a further object of this invention to eliminate the necessity for long term register control means in apparatus of the character described, by providing means for printing impressions which are in register with apertures that are spaced at regular intervals lengthwise along the strip, and which utilize the apertures for maintaining such register.

While the foregoing discussion has made reference only to the synchronization of a single impression roller with a strip or web to be imprinted, the principles of this invention are of course applicable to multi-color printing, and it is thus another object of this invention to control the rotation of a plurality of impression rollers, each printing a different color, so that the successive impressions which the rollers make in a single imprint area are all in register with an aperture in the strip and hence with one another.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come Within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and inwhich:

FIGURE 1 is a more or less diagrammatic side elev-ational view of printing apparatus intended (for imprinting metal and similar substantially stiff material in continuous strip form, embodying the principles of this invention;

FIGURE 2 is a fragmentary view in oblique projection of the printing station of the apparatus shown in FIGURE 1; and

FIGURE 3 is a top elevational View of the printing station shown in FIGURE 2.

Referring now to the accompanying drawings, the numeral 5 designates a strip of metal or similar stiff material having very substantial length and which is to be imprinted or decorated by means of the apparatus of this invention, designated generally by 6. In the machine 6 the strip follows a defined path which carries it from a source, such as a supply reel (not shown) successively through hold back rolls '7, a printing station 8, an oven 9, a cooler 10 and pull through rolls 11, and finally to a rewind stand '12 at which the strip is wound into a compact coil. Those skilled in the art will appreciate that certain stations along the path of strip travel (e.g., the oven or cooler) might be omitted under certain conditions, and that others (such as a coating or lacquering station) might be incorporated into the machine, along the path of strip travel, without departing from the principles of the prevent invention.

Regardless of the number and nature of the stations along the path of strip travel, the strip is drawn through the machine by the pull through rolls 11, which are drivingly connected, through suitable transmission means 13, with an electric motor 14 or other power drive means. The pull through rolls tend to move the strip lengthwise at a substantially uniform speed, but for a number of reasons, explained at length in the aforesaid Kinzelman patent, the local linear speed of the strip at any given station in the machine (and notably at the printing station 8 with which this invention is primarily concerned) may vary more or less substantially from the nominal driving speed of the pull through rolls.

To maintain the strip under some degree of tension as it moves through the machine, and thus constrain it to follow accurately along the path defined by the several rollers that it traverses, the hold back rolls 7 are provided with suitable rotation inhibiting means (not shown) by which they are caused to resist forward movement of the strip Without, however, actually preventing its advance through the machine. Alternatively the hold back rolls could be power driven at a constant speed while the transmission means 13 through which the pull through rolls are driven could include a clutch or similar constant torque drive means whereby the pull through rolls would have a tendency to draw the strip through the machine faster than the hold back rolls would allow it to progress.

The rewind reel 12 is suitably driven in a manner well known to those skilled in the art so as to wind the strip material into a coil at the same rate that it emerges from the machine.

The strip material upon which the apparatus of this invention is adapted to operate is provided with apertures 16 at regularly spaced intervals along its length. The specific shape and arrangement of these apertures is 'of course dependent upon the containers or other articles to be formed up from the strip material after it is imprinted, but it is also within the spirit of the invention to provide the strip with apertures along a marginal edge portion thereof, possibly in the form of notches, which would be utilized only for purposes of maintaining register in accordance with the principles of this invention, such edge portion being subsequently out off of the strip and discarded. It will be apparent as the description proceeds that the term apertures is used herein to refer not only to actual holes in the strip, but also to dimples, embostures and similar regularly spaced local deformations of the material that define the desired abutment means on the strip.

The punch or other means (not shown) for forming the apertures 16 can comprise one of the stations along the path of lengthwise strip travel through the machine or can be entirely apart from the machine. Obviously the incorporation of the punch into the path of strip travel through the printing machine is preferable from the standpoint of efficiency and expediency.

At the printing station 8 the strip passes around an idler roller 17 by which its direction of travel is changed from substantially horizontal to substantially vertically upwardly, and the strip thence passes through one or more printing couples 18, two printing :couples being shown by way of illustration in the present case. Each printing couple comprises an impression roller 19 and a backup roller 20. In this case each impression roller 19 is shown as comprising a blanket or transfer roller oooperable with a plate roller 21, as in offset printing, but it will be understood that it could also be a roller of the direct impression type.

After passing through the printing couples the strip curves around a monitor roller 23 to undergo a change of direction from vertical back to horizontal. The monitor roller 23 and impression rollers 20, like all of the other rollers hereinbefore mentioned, are of course rotatable on axes which are fixed along the defined path of strip travel, being supported for such rotation on suitable frame means 30.

The function of the monitor roller 23 is to maintain penfect synchronism between the circumferential speed of the impression rollers and the linear speed of that portion of the strip with which they are engaged, and to thus insure that any given point on the impression surface (of each impression roller will recurrently engage points on the strip which bear a predetermined relationship lengthwise of the strip to the apertures 16 therein. To this end the monitor roller comprises a part of what is in efiect a geared connection between the strip and each impression roller, and which connection consists of cog-like radial projections or spur members 24 on the monitor roller that are mesllingly engageable in the apertures 16 in the strip, and rotation transmission means 25 which drivingly connects the monitor roller with each impression roller in a manner constraining all of said rollers to rotate in synchronism, at speeds which bear a predetermined relationship to one another. t

Each of the cogs or spurs 24 has a size and shape to fit substantially closely in the apertures 16 in the strip so that the connection between the strip and the monitor roller is substantially without play or backlash. Thus the front and rear edge portions of each aperture in the strip provide iabutment cooperable with the opposing abutments provided by the circumferentially facing surfaces on the cogs to afford a load transmitting connection between the strip and the monitor roller.

Obviously the spacing of the spurs both axially and circumferentially on the monitor roller should be so related to the spacing of the apertures 16 across the width and along the length of the strip as to provide smooth meshing engagement between the spurs and the strip. Smooth engagement of the cogs or spur members with the strip can be further promoted by tapering the cogs radially outwardly as shown. Moreover, the path of strip travel should carry it around a suflicient portion of the monitor roller periphery to insure that at least one cog, or rank of cogs, is at all times fully engaged in the strip. To obtain this relationship it will usually be necessary for the monitor roller to have a circumference which is an integral multiple of the circumference of the impression roller (with the qualification hereinafter noted concerning the thickness of the strip material), and the transmission means 25 by which the rotation of the rollers is synchronized will have to provide a corresponding rotational speed ratio between the monitor and impression rollers.

It will be understood that where the strip is provided with lugs, embossures or similar male abutment means instead of holes, the gear connection of the monitor roller to the strip will be provided by suitable wells or sockets in the monitor roller, opening to its cylindrical surface and closely fitting the male abutment means on the strip.

The rotation transmission means 25 which drivingly connects the monitor roller with the impression roller or rollers comprises a train of gears of the type that are substantially free from backlash, and which establish the required rotational speed ratio between the monitor and impression rollers. It should be mentioned that the relative diameters of the monitor and impression rollers should be so chosen as to make due allowance for the thickness of the strip material and its flexing as it passes around the monitor roller, bearing in mind that the monitor roller periphery engages the rear surface of the strip on an inside radius while the impression rollers engage its front surface. The rotational speed of each impression roller, however, will normally be an integral multiple of that of the monitor roller, without regard to thickness of the strip, and consequently the impressions made by the impression rollers will always be in register with the apertures in the strip, regardless of any variations in the thickness of the strip. In most cases the rotational speed ratio between the monitor and impression rollers is so chosen that the circumferential speed of the impression roller is exactly equal to the local linear speed of that portion of the strip which it engages; but in some special circumstances the gear "train 25 might be so arranged as to provide the impression roller with a circumferential speed which is in some other predetermined ratio to strip speed than the normal one-to-one.

Desirably the monitor roller is located as close as possible to the printing couples along the path of lengthwise strip travel, to insure that the local speed of the strip at the monitor roller will at all times be equal to that at the impression rollers.

From what has been said above it can be seen that the synchronism of the impression rollers with the strip is maintained by the gearing of the monitor roller to the strip, but it will also be apparent that if the strip were called upon to drive the monitor and impression rollers and the gear train 25 connecting them, the cogs or spur members 24 would present substantially large load forces to the strip that could result in deformation of the strip at the edge portions of the apertures. To avoid this undesirable possibility there is provided a constant torque drive means 27 which is idrivingly connected to the rollers 19 and 23 and which supplies enough torque to said rollers to turn them at a circumferential speed which approximates the linear speed of the strip; and the nec essary corrective torque to bring the circumferential speed of said rollers to exactly the local linear speed of the strip is derived from the small load which is presented to the strip by means of the spur members. Because the monitor and impression rollers are gear connected, the constant torque drive means can have its output shaft 28 directly coaxially connected to either of them, or even to one of the gears of the transmission 25, but in this case it is illustrated as having a direct driving connection to the monitor roller 23.

To impart to the rollers 19 and 23 a torque force which has a constant value, regardless of the rotational speed of the rollers, the constant torquedrive means comprises a constant speed motor 31 which is coupled to the roller train through a slip clutch 32 and a speed reducer 33. The speed reducer may be a conventional gear box transmission and is provided for the purpose of matching the motor speed to the required speed of the monitor roller.

The slip clutch 32, which assures the imposition of a constant torque force upon the rollers, regardless of their rotational speed, is preferably of the eddy current or hysteresis type, to avoid the necessity for periodic adjustment to compensate for frictional wear on mechanical clutch surfaces.

By adjustment of the coupling value of the clutch and proper selection and/or adjustment of the gear ratio of the speed reducer 33, the rollers 19 and 23 are driven, in the absence of the strip, at a circumferential speed which is equal to the nominal forward speed of the strip through the machine. Hence if the local speed of the strip through the printing couples increases or decreases to values above or below that nominal speed, light load forces will be imposed upon the spur members 24 by which the monitor and impression rollers will be accelerated or decelerated to maintain their circumferential speeds at all times exactly equal to the local linear speed of the strip, it being understood that the circumferential speed of the monitor roller is equated to the linear speed of the smaller radius rear face of the strip in contact therewith.

The provision of the constant torque drive means not only prevents deformationof the strip by the spur members but also insures smooth meshing engagement between the strip and the spur members, due to the small loads which the strip and spur members present to one another, and thus further insures that the successive impressions made by each impression roller will be accurately in lengthwise register with the apertures in the strip.

From the foregoing description taken together with the accompanying drawings, it will be apparent that this invention provides means for so controlling the rotation of an impression roller in apparatus for printing metal and similar stiff material in continuous strip form that the successive impressions made by the impression roller will all be in accurate register with apertures in the strip located at regularly spaced intervals along its length.

What is claimed as my invention is:

1. In apparatus for printing impressions upon a con- 7 tinuous strip of metal or the like that has apertures at regularly spaced intervals along its length, and wherein an impression roller by which such impressions are printed is mounted at a fixed location along a defined path of lengthwise strip travel for rotation in engagement with the strip, means for controlling the rotation of the impression roller to continuously maintain its circumferential speed in a predetermined ratio to the local linear speed of the strip portion engaged thereby and to recurrently engage a point on the roller with points on the strip which bear a predetermined relationship lengthwise of the strip to the apertures therein, so that the impressions made by the impression roller are unsmeared and are accurately in register with the apertures, said means comprising: strip drive means for drawing a strip lengthwise along said defined path; a monitor roller mounted to rotate about a fixed axis along said defined path and to be engaged by the strip, said monitor roller having cog-like projections which are adapted to closely fit said apertures and which are circumferentially spaced apart by distances so related to the spacing of the apertures lengthwise along the strip that said projections are adapted to mesh with apertures in the strip, to gear the monitor roller to the strip; transmission means providing apositive rotation transmitting connection between the monitor roller and the impression roller which constrains said rollers to rotate in synchronism at a predetermined ratio of circumzferential speeds; and constant torque drive means drivingly connected with said rollers to drive them at a 7 speed which is independent of the speed of the strip drive means and to impart to them a torque of a value which tends to rotate them at a speed such that the circumferential speed of the monitor roller approximates the linear speed of the strip, so that the torque forces necessary to make the circumferential speed of said impression roller at all times bear saidpredetermined ratio to the local linear speed of the strip are derived from the strip itself, through the gearing of the monitor roller thereto, and so that said forces are light enough to prevent deformation of the strip around the edges of its apertures as a result of the meshing engagement of the radial projections therewith.

2. The apparatus of claim 1, wherein said transmission means comprises a gear connection between said rollers.

'3. The apparatus of claim 1, wherein said constant torque drive means connected with said rollers comprises a constant speed motor; and wherein said motor is drivingly connected with one of said rollers through transmission means that comprises means permitting variations in the relative speeds of the motor and said one roller without disruption of the torque transmitting relation therebetween.

4. The apparatus of claim 1, wherein the monitor roller has a circumference which is substantially a multiple of the circumference of the impression roller; and wherein the defined path of strip travel disposes the strip partway around the monitor roller, with at least one of said coglike radial projections on the monitor roller at all times engaged in an aperture in the strip.

5. The apparatus of claim 1, further characterized by: a backup roller mounted adjacent to the impression roller, at the face of the strip opposite to that engaged by the impression'roller, cooperable with the impression roller to define a portion of the path of strip travel and by which the strip is held engaged with the impression roller, said backup roller being freely rotatable so as to be driven by the strip itself.

6. The apparatus of claim 1, further characterized by: a second impression roller mounted for rotation about a fixed axis at another location along the path of strip travel; and second transmission means providing a positive driving connection between the second impression roller and the first mentioned rollers and constraining the second impression roller to rotate in synchronism with the first designated impression roller so that impressions made upon the strip by said impression rollers are in register with one another as well as with the apertures in the strip.

7. In apparatus for printing impressions upon a continuous strip of metal or the like that has apertures at regularly spaced intervals along its length, and wherein an impression roller by which such impressions are printed is mounted at a fixed location along a defined path of lengthwise strip travel for rotation in engagement with the strip, means for controlling the rotation of the impression roller to continuously maintain its circumferential speed in a predetermined ratio to the local linear speed of the portion of the strip engaged thereby and to recurrently engage a point on the printing surface of the impression roller with points on the strip which bear a predetermined relationship lengthwise of the strip to the apertures therein, so that the impressions made by the impression roller are unsmeared and are accurately in register with the apertures, said means comprising: strip drive means for drawing a strip lengthwise along said defined path; means providing a positive driving connection between the strip and the impression roller, said means comprising cog-like elements which are constrained to orbital movement and which mesh with the apertures in the strip, and means constraining the impression roller to rotate at a speed which is in a predetermined ratio to orbital speed of the cog-like elements; and constant torque drive means connected with the impression roller for driving the same independently of the strip drive means and for supplying torque thereto of a constant value which tends to rotate the impression roller at a circumferential speed that approximates a predetermined ratio to the linear speed of the portion of the strip engaged therewith, the meshing of the spur members with the strip maintaining the circumferential speed of the impression roller in exactly said ratio to the local linear speed of the strip portion engaged therewith regardless of variations in the speed of strip travel, the torque supplied by said constant torque drive means assuring that the load presented to the strip by the spur members is at all times a light one, incapable of effecting deformation of the strip around the edge portons of the apertures therein.

8. In apparatus for printing impressions upon a continuous strip of metal or the like that has abutment means formed thereon at regularly spaced intervals along its length, and wherein an impression roller by which such impressions are printed is mounted at a fixed location along a defined path of lengthwise strip travel for rotation in engagement with the strip, means for controlling the rotation of the impression roller to continuously maintain its circumferential speed in a predetermined ratio to the local linear speed of the strip portion engaged thereby and to recurrently engage a point on the roller with points on the strip which bear a predetermined relationship lengthwise of the strip to the abutment means thereon, so that the impressions made by the impression roller are unsnreared and are accurately in register with the abutment means, said means comprising: strip drive means for drawing a strip lengthwise along said defined path; means cooperable with the abutment means on the strip to provide a geared connection between the strip and the impression roller, said means comprising abutment elements carried for motion in an orbit fixed with respect to said defined path; and constant torque drive means drivingly connected to the impression roller to drive the same independently of the strip drive means and to impart to the impression roller a torque of a value to rotate the same at a circumferential speed that approximates a predetermined ratio to the linear speed of the strip, the geared connection between the strip and the impression roller insuring that the circumferential speed of the impression roller exactly equals said ratio of the local linear speed of the strip portion engaged therewith, despite variations in strip speed, and the torque supplied to the impression roller by said constant torque drive means insuring that forces exerted upon the strip by said abutment elements will at all times be small enough to prevent deformation of the strip.

References Citetl in the file of this patent 10 Nardone Oct. 21, 1947 Fulk Dec. 11, 1956 Kinzelman June 16, 1959 Stobb Aug. 11, 1959 Bcrch-Madsen Jan, 31, 1961

Claims (1)

1. IN APPARATUS FOR PRINTING IMPRESSIONS UPON A CONTINUOUS STRIP OF METAL OR THE LIKE THAT HAS APERTURES AT REGULARLY SPACED INTERVALS ALONG ITS LENGTH, AND WHEREIN AN IMPRESSION ROLLER BY WHICH SUCH IMPRESSIONS ARE PRINTED IS MOUNTED AT A FIXED LOCATION ALONG A DEFINED PATH OF LENGTHWISE STRIP TRAVEL FOR ROTATION IN ENGAGEMENT WITH THE STRIP, MEANS FOR CONTROLLING THE ROTATION OF THE IMPRESSION ROLLER TO CONTINUOUSLY MAINTAIN ITS CIRCUMFERENTIAL SPEED IN A PREDETERMINED RATIO TO THE LOCAL LINEAR SPEED OF THE STRIP PORTION ENGAGED THEREBY AND TO RECURRENTLY ENGAGE A POINT ON THE ROLLER WITH POINTS ON THE STRIP WHICH BEAR A PREDETERMINED RELATIONSHIP LENGTHWISE OF THE STRIP TO THE APERTURES THEREIN, SO THAT THE IMPRESSIONS MADE BY THE IMPRESSION ROLLER ARE UNSMEARED AND ARE ACCURATELY IN REGISTER WITH THE APERTURES, SAID MEANS COMPRISING: STRIP DRIVE MEANS FOR DRAWING A STRIP LENGTHWISE ALONG SAID DEFINED PATH; A MONITOR ROLLER MOUNTED TO ROTATE ABOUT A FIXED AXIS ALONG SAID DEFINED PATH AND TO BE ENGAGED BY THE STRIP, SAID MONITOR ROLLER HAVING COG-LIKE PROJECTIONS WHICH ARE ADAPTED TO CLOSELY FIT SAID APERTURES AND WHICH ARE CIRCUMFERENTIALLY SPACED APART BY DISTANCES SO RELATED TO THE SPACING OF THE APERTURES LENGTHWISE ALONG THE STRIP THAT SAID PROJECTIONS ARE ADAPTED TO MESH WITH APERTURES IN THE STRIP, TO GEAR THE MONITOR ROLLER TO THE STRIP; TRANSMISSION MEANS PROVIDING A POSITIVE ROTATION TRANSMITTING CONNECTION BETWEEN THE MONITOR ROLLER AND THE IMPRESSION ROLLER WHICH CONSTRAINS SAID ROLLERS TO ROTATE IN SYNCHRONISM AT A PREDETERMINED RATIO OF CIRCUMFERENTIAL SPEEDS; AND CONSTANT TORQUE DRIVE MEANS DRIVINGLY CONNECTED WITH SAID ROLLERS TO DRIVE THEM AT A SPEED WHICH IS INDEPENDENT OF THE SPEED OF THE STRIP DRIVE MEANS AND TO IMPART TO THEM A TORQUE OF A VALUE WHICH TENDS TO ROTATE THEM AT A SPEED SUCH THAT THE CIRCUMFERENTIAL SPEED OF THE MONITOR ROLLER APPROXIMATES THE LINEAR SPEED OF THE STRIP, SO THAT THE TORQUE FORCES NECESSARY TO MAKE THE CIRCUMFERENTIAL SPEED OF SAID IMPRESSION ROLLER AT ALL TIMES BEAR SAID PREDETERMINED RATIO TO THE LOCAL LINEAR SPEED OF THE STRIP ARE DERIVED FROM THE STRIP ITSELF, THROUGH THE GEARING OF THE MONITOR ROLLER THERETO, AND SO THAT SAID FORCES ARE LIGHT ENOUGH TO PREVENT DEFORMATION OF THE STRIP AROUND THE EDGES OF ITS APERTURES AS A RESULT OF THE MESHING ENGAGEMENT OF THE RADIAL PROJECTIONS THEREWITH.

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