US3416444A - Web registry for flexographic presses - Google Patents

Description

Dec. 17, 1968 L. .1. CAHN WEB REGISTRY FOR FLEXOGRAPHIC PRESSES Original Filed Oct. 16, 1962 e She ts-Sheet 1 INVENTOR.

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L EON J. CAHN ATTO RN EYS.

Dec. 17, 1968 J. CAHN, 3,416,444

' WEB REGISTRY FOR'FLEXOGRAPHIC PRESSES' 6 Sheets- Sheet 4 Original Filed Oct. 16, 1962 INVENTOR. LEON .1. CAHN ATTORN EYS L. J. CAHN WEB REGISTRY FOR FLEXOGRAPHIC PRESSES Original Filed Oct. 16, 1962 Dec. 17, 1968 6 Sheets-Sheet 5 N H @A mc V J N o E ATTORNEYS Dec. 17, 1968 J. cAHN I WEB REGISTRY FOR FLEXOGRAPHIC PRESSES Original Filed Oct. 16, 1962 6 Sheets-Sheet 6 FIC5.II

Faaus INVENTOR. LEON J. CAH N ATTORN EYS United States Patent 3,416,444 WEB REGISTRY FOR FLEXOGRAPHIC PRESSES Leon J. Cahn, Long Islands City, N.Y., assignor to Lee .Machinery Corporation, New York, NY. Original application Oct. 16, 1962, Ser. No. 230,953, now Patent No. 3,233,539, dated Feb. 8, 1966. Divided and this application Sept. 16, 1965, Ser. No. 487,823

4 Claims. (Cl. 101181) ABSTRACT OF THE DISCLOSURE A web registry means for a flexographic press having multiple printing stations whereby rollers are employed intermediate a. pair of printing stations and are caused to enter into greater or lesser contact with the non-indicia bearing surface of the web passing through said printing stations to obtain the proper registry of the printed indicia on the web.

This is a divison of application Ser. No. 230,953, filed Oct. 16, 1962, now US. Patent 3,233,539.

The present invention relates to printing presses and, more particularly, to presses generally known as flexographic presses.

Flexography or aniline printing is a specialized form of relief printing for printing on materials; such as, cellophane, polyethylene, which have surfaces not capable of being handled by ordinary letter press methods of printing. In flexographic presses the printing is accomplished generally by flexible rubber plates carried by the printing cylinders of web-fed rotary presses. The rubber plates are generally inked by a single inking roller and the material to be printed is fed between the press plate cylinder and its associated impression cylinder.

Generally, these flexographic presses print multiple colors with a plate cylinder and coacting impression cylinder, each associated with a particular color to be printed. It will be understood that in multiple ink work, proper registration of the web between successive printing stations in the press is critical. Heretofore, however, the press generally had to be stopped to reregister the web, which is time-consuming and costly.

The present invention is characterized by the provision of means for ensuring proper registration between successive printing stations while the press is running. Between successive printing stations there is provided a compensator roller mounted for movement toward and away from the web and against the surface thereof not being printed. The compensator roller momentarily increases or decerases the tension in the web between printing stations, thereby effecting a retarding or speeding up of the web between successive printing stations. Thus, the operator can control the running web to maintain proper registry an essential feature for multiple color printing and not heretofore available in flexographic printing.

Likewise, in flexographic presses for multiple color (generally, four colors), it may be desirable to print only two colors or it may be desirable to deactivate all printing stations during web replacement. Accordingly, means are provided in the present invention for deactuating by means of a single lever the four printing stations. A linkage arrangement is provided whereby a single lever movement effects lateral movement of the four printing cylinders away from their related impression cylinders. Means is also provided for moving the printing cylinders on each side of the press away from their associated inking rollers. An actuator handle and link arrangement effects intermovement of these printing cylinders toward and away from their associated inking rollers when only two color printing is desired. Thus, the arrangements permit the "ice ink fountain rollers :and/or plate cylinders to continue to rotate, agitating the ink, while the printing is temporarily interrupted, thus preventing ink from accumulating on the plate cylinders and/or ink fountain rollers.

To provide for ready access to the ink fountains for maintenance and other reasons, each ink fountain is removably supported on spaced cams. In their upward position the cams locate the ink fountains adjacent to the ink fountain roller. In their downward position, the ink fountains are spaced from their fountain rollers. This simple arrangement provides for ready access to the press ink fountains Without the unbolting required heretofore.

Generally, fiexographic presses are run roll-to-roll with the printing web being rewound. To insure proper tension and web rewind, there is provided automatic control means responsive to web slack for increasing or decreasing the speed of the rewind motor. This control means includes a counter-weighted dancer roller, electrically associated with a variable speed motor in turn driving the web rewind shaft. As the dancer roller position changes in accordance with the web tension, the rewind motor is driven faster or slower in response thereto to maintain the proper tension in the web and proper web rewind feed.

Likewise, to facilitate tearing of the imprinted web when such tearing is desired, the press of the present invention includes a scoring mechanism operative, after the web has been completely imprinted, to provide longitudinal score lines in the printed web as it travels toward the press rewind section.

Objects It is therefore the object of the present invention to provide a novel flexographic printing press.

It is also an object of the invention to provide in a fiexographic printing press, novel means for maintaining registry of the running web between successive printing stations.

A further object of this invention is to provide in a flexographic printing press, novel means for maintaining registry of the running web between successive printing stations, including web tension control means for effecting the web travel rate between successive printing stations.

Another object of the invention is to provide in a flex-ographic printing press novel means for supporting and simultaneously moving the press printing cylinders laterally toward and away from their associated impression cylinders, including a single lever actuator and related linkages.

It is an added object of the present invention to provide in a flexographic printing press having a plurality of printing stations with at least one on each side of said press, novel linkage means mounting and supporting the ink fountain rollers on each side of said press for simultaneous movement toward and away from their associated inking rollers by the single movement of a linkage actuator.

Another object of the present invention is to provide a novel web rewind mechanism response to web tension for increasing or decreasing the rate of web rewind whereby proper web tension is maintained during rewind.

A further object of the invention is to provide in a flexographic printing press, means for selectively controlling the rate of web rewind in accordance with web tension, including a counter-weighted dancer roller electrically associated with the web rewind means.

An additional object of the invention is to provide rotatable cam supports for the ink fountains of a fiexographic printing press whereby said fountains are readily movable from their operative inking position for desired access thereto.

It is likewise an object of the present invention to provide in a flexographic press novel score means for cutting longitudinal score lines in the web running through said press.

Other objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be leaned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic view of the web path through the press.

FIGS. 2, .3 and 4 are schematic views illustrating the several positions of the printing cylinders, ink fountain rollers, ink fountains and web registration tension control rollers.

FIG. 5 is a schematic view of the rewind section of the press.

FIG. 5A is a sectional view taken along line 5A--5A, FIG. 5.

FIG. 6 is a side elevation of the press embodying the present invention and illustrating one ink fountain in nonoperative position.

FIG. 7 is a detailed side elevation of the ink fountain and printing cylinder control mechanisms.

FIG. 8 is a perspective view partly broken away of the printing cylinder control mechanism.

FIG. 9 is a front view of the printing cylinder control actuating rods.

FIG. 10 is a perspective view partly broken away of the printing cylinder and ink fountain supports.

FIG. 11 is a side elevation partly in section of the ink fountain and associated elements in operative position.

FIG. 12 is a view taken along line 1212, FIG. 11.

FIG. 13 is a side elevation partly in section of the ink fountain and associated elements in nonoperative position.

FIG. 14 is a front view of the web registration control roller actuating mechanism.

General description Referring specifically to FIGS. 1 and 6, the material to be printed, preferably cellophane or polyethylene, is fed from a supply roll R rotatably carried on shaft 11 by the main frame F of the four-color flexographic press 10. In normal operation, the material web W is fed under inside idler roller 12 and thence around draw roller 14, preferably of rubber or similar material. From draw roller 14, web W passes under the lower impression cylinder 16 and between impression cylinder 16 and the first printing plate cylinder 18 at printing station 1. Web W is then fed successively (a) between upper impression cylinder 20 and the second printing plate cylinder 22 at printing station II, (b) over top compensator roller 24, (c) between upper impression cylinder 20 and the third plate printing cylinder 26 at printing station III, ((1) between lower impression cylinder 16 and the fourth printing plate cylinder 28 at printing station IV.

From station IV, printed web W is trained around idler rollers 30, 32, 34, 36 and 38, as it travels from press 10 through heated drying tunnel T. It will be understood that in drying tunnel T the ink on web W is dried and set. From tunnel T web W enters the press rewind section, designated generally S.

In section S, web W is first fed around spaced idler rollers 40 and 42. Web W is then brought over the dancer roller 44 and thence around another idler roller 46 and onto reel 49 on rewind shaft 48.

In normal operation, web W is traveled successively through printing stations I, II, III and IV, and at each printing station a separate color is imprinted on web W by printing plate cylinders 18, 22, 26 and 28. Usually, heat means (not shown) are disposed between successive printing stations and in drying tunnel T for hastening the final drying and setting of the ink deposited on web W. Web W is drawn from roll R by the coaction of impression cylinder 16 and draw roller 14 which are driven by a suitable conventional power source (not shown) which may include a variable speed motor and a belt and pulley system. The web W is also urged through press 10 by the rotation of rewind shaft 48 as described more fully hereinafter.

Printing cylinders and associated mechanisms Printing plate cylinder 18 is mounted on a shaft 50 supported at each end transversely in press 10 by upright extension 52 of printing plate cylinder frame 54. (See FIGS. 7, 8 andlO). Frame 54, in turn, is slidably mounted on a support plate 55 seated in a suitable keyway 56 formed in cross-arm 58 of the press frame F. The ink fountain roller 60 associated with plate cylinder 18 is mounted on a shaft 62 and disposed parallel to cylinder 18. Shaft 62 is carried at each end in a link arm 64 pivotally connected to an extension 66 of the ink fountain carriage 68. Carriage 68 in turn is slidably supported on a plate 69 mounted in a suitable keyway 70 formed in printing cylinder frame 54 (see FIG. 10).

Plate cylinder frame 54 is adapted for travel along its associated support plate 55 by means of threaded shaft 57 carried by bracket 59 fixed to the end of plate 55 remote from cylinder 18. The turning of handle 59 located on shaft 57 is operative to move frame 54 back and forth along plate 55. This arrangement enables printing cylinder 18 to be moved into contact with its associated printing cylinder 16 at the start of printing operations and gives press 10 great flexibility in the length printed therewith.

Likewise carriage 68 is adapted to travel along its associated support plate 69 by means of threaded shaft 71 carried by bracket 73 fixed to the end of plate 69 remote from roller 60. The turning of handle 75 on shaft 71 is operative to move carriage 68 back and forth along plate 69 as desired.

It is understood that plate cylinder 18 is provided with the same support elements at each side of the press 10. However, for brevitys sake, only the elements on the side of the press shown have been described in detail. It will likewise be understood that each printing plate cylinder 18, 22, 26 and 28 has the same support elements associted therewith and in the interests of brevity a detailed description of the elements of cylinder 18 and station I only is given.

Printing cylinder actuating mechanism Means is provided for simultaneously moving printing cylinders 18, 22, 26 and 28 into and out of operative position. FIG. 6 shows printing cylinders 18, 22, 26 and 28 in operative printing position adjacent their associated impression cylinders 16 and 20, while FIG. 7 shows the printing cylinders in non-operative position and spaced from the impression cylinders.

To accomplish this, each printing cylinder frame support plate 55 is pivotally attached to one end of a crank arm 72, as best shown in FIG. 8. The other end of crank arm 72 is fixed to and rotatable with an eccentric 74. In turn, eccentrics 74 are secured to central shaft 76 for printing stations I and IV, and to shaft 78 for printing stations II and III. Shafts 76 and 78 are supported at each end of the press frame F.

Shafts 76 and 78 are also furnished at one side of the press with actuating bars 80 and 82, respectively, Actu ating bars 80 and 82 are interconnected by a generally vertical link member 84. Bars 80 and 82 are rotatable with their associated shafts 76 and 78 and upper shaft 78 includes an actuating handle 86 for effecting rotation of its associated shafts 78.

In operation, to move printing cylinders 18, 22, 26 and 28 from the operative printing position shown in FIG. 6 to the non-operative position shown in FIG. 7, handle 86 is rotated in the direction of arrow A, FIG. 6, to its position shown in FIG. 7. This, in turn, rotates shafts 76 and 78 through the action of bars 80 and 82, and link member 84. Rotation of shafts 76 and 78 moves the high point 75 of eccentrics 74 toward their associated printing cylinder frames 54, effecting sliding travel of printing cylinder frames support plates 55 in their associated keyways 56, moving the printing cylinder frames 54 locked to plates 55 by shaft 57 away from the associated impression cylinders. To move the printing cylinders 18, 22, 26 and 28 into operative position adjacent their associated impres sion cylinders, the position of handle 86 is reversed, in turn reversing the direction of travel of the associated linkage arrangement to move the printing cylinder frames toward their associated impression cylinders.

Ink fountain roll actuating mechanism Means is provided for simultaneously moving the ink fountain rollers at stations I and II and at stations III and IV simultaneously away from their associated printing cylinders. To accomplish this, the ink fountain carriages support plates 69 at stations I and II are each pivotally connected to one end of an associated crank arm 88. The other end of arm 88 is mounted on an eccentric 90 secured to a stud shaft 92, carried by printing cylinder frame 54. Stud shafts 92 at station I are fixed to one end of an actuating bar 94. The other end of bar 94 is pivotally connected to one end of a generally vertically disposed link member 96. The other end of link member 96 is pivotally attached to one end of an actuating lever 98. Lever 98 adjacent its midpoint, is fixed to and rotatable with stud shaft 92 while its free end includes an actuating knob 100.

To move ink fountains at stations I and II from the nonoperative position shown in FIG. 7 to their operative positions shown in FIG. 6, handle 98 is rotated in the direction of arrow B, FIG. 7. This, in turn, will effect a rotation of both stud shafts 92 by the above described linkage system. Rotation of shafts 92 by this movement of actuating lever 98 urges the high point 89 of eccentrics 90 toward impression cylinders 16 and 20 travelling the ink fountain carriage support plate 69 and the carriage 68 thereon toward their associated printing cylinders,

It will be understood that the mechanism for moving the ink fountains at stations III and IV are identical to the described elements for rrioving the ink fountains at stations I and II, and the detailed description thereof is omitted is the interest of brevity.

Web registry control mechanism As web W travels between printing stations I, II, HI and IV, the speed thereof may vary slightly due to press web or variation in web rewind speed. Such variation between printing stations, however, throws the web 01f registry resulting in successive printed images on the web that do not register.

To correct this situation, means is provided for correcting registration of the web between successive printing stations by increasing or decreasing the web speed between stations by means of a decrease or increase of the web tension. To accomplish this, a pivot rod 102 is transversely supported at each end in suitable bearings in upright 104 of press frame F. Rotatably mounted in rod 102 at each end thereof are worm gears 106 and 108, coacting with worms 110 and 112, respectively, carried at one end of their associated worm rods 114 and 116. Activating knobs 118 and 120 are mounted on worm rods 114 and 116 remote from their respective worms 110 and 112, while worm rods 114 and 116 are carried by brackets 11 5 and 117 on uprights 104 Each worm gear 106 and 108 is associated with a compensator roller 122 and 124 disposed parallel to pivot rod 102 as shown in FIGS. 7 and 14. Roller 122 is freely supported at each end in a pair of spaced link arms 126 and 128 rotatably carried by rod 102. Arm 126 is fixed to and rotatable with worm gear 106 such that suitable rotation of knob 118 pivots roller 122 about rod 102 in the direction of arrows C, FIG. 7.

Roller 124, in turn, is freely supported at each end in a pair of spaced link arms 130 and 132 rotatably carried by rod 102. Arm 130 is fixed to and rotatable with worm gear 108 such that suitable rotation of knob 120 pivots roller 124 about rod 102 in the direction of arrows D, FIG. 7.

In operation, when web W is out of registry between stations I and H, and it is desired to retard the web travel therebetween, knob 120 is activated to pivot roller 124 toward web W, slightly stretching the web between stations I and II. This momentarily increases the tension in the web, retarding its travel and thereby bringing web W into registry at station II. Conversely, if it is desired to increase the rate of travel of web W between stations I and II to bring web W into registry, knob 120 is activated to pivot roller 124 away from web W, relieving the tension in web W momentarily and thereby bringing web W into registry at station II.

In like manner, roller 122 is pivoted toward and away from web W by suitable movement of knob 118 to bring web W into registry between stations III and IV. It will be understood that since both rollers 122 and 124 bear against the face of web W remote from the printed surface, rollers 122 and 124 in no way interfere with the successive printing operations.

Likewise, upper compensator roller 24 is provided with means for moving laterally to momentarily increase or decrease tension in web W between stations II and III to maintain web registry. Roller 24 is rotatably mounted in spaced arms 134 and 136 fixed to a cross-shaft rotatably supported by brackets 138, 139 on uprights 104.

At one end of shaft 135, there is provided a worm gear 140 coacting with a suitable worm 142 and adapted for travel therealong. Worm 142 in turn is carried at one end of a worm rod 144 rotatably supported in bracket 139 on upright 104. Knob 148 is adapted for activation of worm 142 to travel worm gear 140 therealong to pivot roller 124 against or away from web W as desired to speed up or retard the web travel between stations II and III to ensure web registry therebetween.

Thus, means are provided for ensuring web registry between successive printing stations in the press embodying the present invention.

Ink fountain supports Each ink fountain roller 60 has associated therewith an inking roller 150 mounted on shaft 152 rotatably carried by ink fountain carriage 68. Each inking roller 150 is adapted for rotation into the ink supply carried by an associated ink fountain 154 at each printing station. Fountains 154 each include a trough 156 resting on a support plate 158 and having an end bracket 160 (only one shown) on each side thereof with an opening 161 for accommodating alignment studs 163. Plate 158 has fixed thereto at each'end a block member 162 slidably mounted in vertical channel brackets 164 fixed to carriages '68.

Means is provided for traveling trough 156 into and out of operative association with its inking roller 150. Plate 158 rests on a pair of spaced actuating cams 166, only one of which is shown in FIGS. 11-13. Cams 166 are fixed to and rotatable with cam shaft 168 rotatably supported in stop blocks 170 at the lowermost ends of brackets 164. Shaft 168 likewise is provided with suitable cam shaft actuating handles 172, disposed between cams 166.

In operation, plate 158 is supported at all times on a surface of cams 166 only. When trough 156 is in operative position, plate 158 rests on the flat high point 174 of cams 166 (see FIG. 11). When it is desired to remove fountain 154 from its operative position for maintenance or an ink change, handles 172 are rotated in the direction of arrow B, FIG. 11. This causes plate 158, now on curved face 174 of cams 166, to travel downwardly in brackets 164 to its lowermost nonoperative position shown in FIG. 13. At this nonoperative position, plate 158 rests on the flat low point 178 of cams 166 and trough 156 can be readily removed therefrom by simply lifting it off its seat on plate 158.

To return fountain 154 to its operative position adjacent its associated roller 150, movement of handles 172 is reversed, moving plate 158 and its associated trough 156 upwardly toward roller 150. This arrangement greatly simplifies removal and replacement of ink and maintenance of the ink fountain and rollers which heretofore required unbolting of the trough for each removal operation.

It will be understood that each inking roller at each printing station has associated fountain mechanisms of similar construction and operation, as described hereinabove. Further, the fountain support mechanism on each side of the press is the same. Repetition of duplicate parts on each side of the press and at each printing station has been omitted in the interests of clarity and brevity.

Web rewind mechanism After web W has been completely imprinted and the web W travelled through the drying tunnel, web W is trained over idler rollers 40 and 42 at the rewind section of the press. From idler 42, Web W passes over dancer roller 44, around idler 46 and onto rewind shaft 48. Rollers 40, 42, 46 and 48 are carried in side plates 180* and 182 of the press frame F.

Dancer roller 44, however, is mounted on a shaft 45 carried at each end in bearing blocks 184 and 186 slidably mounted on an associated vertical slide rod 188 and 190 fixed to the top of its side plates 180 and 182. Also fixed to shaft 45 between the ends of roller 44 and blocks 184 and 186 are anchors 192 and 194 to which are attached the ends of a link chain 196 and 198, respectively. Each chain 196 and 198 in turn is trained around an associated sprocket 200 and 202 on shaft 204 rotatably carried at the upper ends of rods 188 and 190. The other end of chains 196 and 198 are each fixed to an associated lever member 206 and 208 pivotally attached, as at 210 and 212, respectively, to side plates 180 and 182. Each lever 206 and 208 accommodates an associated counterweight 214 and 216 and levers 206 and 208 are tied together for coaction by tie rod 218.

Pivotally connected to block 184 is one end of arm 220 of a suitable electro-mechanical rotary transducer 222. Transducer 222 is preferably of synchro-transformer having a primary energized by alternating current and a secondary which is rotated by movement of arm 220 to produce a voltage output as a function of the dancer position. Transducer 222 is fixed to a bracket 224 on side plate 184 and is electrically connected through a suitable control panel 226 and rectifier unit 228 to the rewind motor 230, which is preferably a direct-current, variable speed motor, such as, a servo-speed motor. The output shaft 232 of motor 230 is provided with a drive pulley 234. Pulley 234 has trained thereabout an endless pulley belt 236, the other end of which passes around pulley 238 on rewind shaft 48.

The proper tension on web W produces the best results in rewinding. To provide the proper web tension, dancer roller 44 is maintained at a selected position on rods 188 and 190 for any given material. To accomplish this, counterweights 214 and 216 are provided to counterbalance the selected tension force to be exerted on dancer 44 by web W. For example, it has been found that for polyethylene and like material, a tension force of 6 lbs. for a 20" wide roll of 1.5 mils thickness is desirable, while for cellophane 17.6 lbs. is best for a roll 22" wide.

Other materials likewise have preferred web rewind tensions.

When tension in web W exceeds the effect of counterweights 214 and 216, dancer 44 moves downwardly, slowing motor 230. When tension in web W is less than the effect of counterweights 214 and 216, dancer 44 moves upwardly along rods 188 and speeding up motor 230.

At the start of automatic rewind, the speed of motor 230 is adjusted to the desired rate of web rewind, normally 300-400 feet per minute, but occasionally up to 600-700 feet per minute. As the rewound web increases, the speed of motor 230 is adjusted by dancer 44 to maintain constant tension of web W. As a safety, when dancer 44 has moved upwardly or downwardly to the extreme top or bottom of rods 188 and 190, transducer voltage output is zero, stopping motor 230.

Scorer mechanism To provide score lines in web W, there is provided a suitable scorer mechanism 240, coacting with idler roller 30 to cut longitudinal scorer lines in web W as it leaves printing station IV and before it enters drying tunnel T. It will be understood that web W is disposed between roller 30 and scorer 240 during the scoring operation.

Scorer 240 includes a scorer drum 242 having annular cutters 244 thereon. Drum 242 is mounted on bushing 246, mounted on rod 248 adjustably carried in brackets 250 and 252 on shaft 31 of idler roller 30-.

To adjust the location of the score lines on the web W, bushing 246 is disposed between arms 254 and 256 slidably mounted on rod 248 and tied together by plate 258. The other end of arm 256 is provided with a threaded recess 260 and thus adapted for travel along screw member 262 rotatably carried by screw support arms 264 and 266 on rod 248. Handle 268 on screw 262 is provided for actuating screw 262 to travel arm 256 therealong, moving scorer 240 laterally relative to web W on roller 30 to the desired location for the longitudinal score lines in web W.

I claim:

1. In a flexographic press for printing multiple impressions on a traveling web at a plurality of spaced printing stations, said press having a plurality of impression cylinders, means rotatably mounting spaced printing plate cylinders adjacent said impression cylinders with the axes of said printing plate cylinders parallel and generally coplanar with the axes of said associated impression cylinders, each printing plate cylinder together with an associated impression cylinder constituting a printing station, means for continuously traveling said web between the printing plate cylinder and the associated impression cylinder at each station, said printing plate and impression cylinders being arranged such that said web in passing successively from station to station loops back on itself with different portions of the unprinted surface of the web facing each other and with each of said different portions extending between a pair of said stations, whereby said printing plate cylinders and said associated impression cylinders are constructed and arranged to place printed indicia on the same face of said web at each of said printing stations, and means for maintaining registry of said printed indicia as said web travels through successive printing stations comprising a common shaft positioned between said different portions of said web, a pair of rollers, each roller being separately mounted on arms which extend from said common shaft; means for individually rotating the arms of each of said rollers about said common shaft to bring each roller into greater or lesser contact with said web whereby the registry of said web is maintained between different pairs of spaced printing stations.

2. The fiexographic press of claim 1 wherein said means for individually rotating each of said rollers on a common shaft includes a pair of arms rotatably mounting each of said rollers to said common shaft, each pair of said arms having a worm gear fixed thereto and means to operate said worm gear including a gear, an operating shaft extending from said gear and an operating handle aflixed to said shaft.

3. In a flexographic press for printing multiple impressions on a traveling web at four spaced printing stations, said press having upper and lower impression cylinders with their respective axes substantially parallel and disposed in a generally relationship, means rotatably mounting a pair of spaced printing plate cylinders on opposite sides of and adjacent each of said upper and lower impression cylinders and having the axes of each of said pair of printing plate cylinders parallel and generally coplanar with the axes of associated impression cylinders, means for continuously traveling said web between said printing plate cylinders and said upper and lower impression cylinders thereby forming a generally inverted U-shaped web con-figuration through said printing stations whereby said printing plate cylinders and said associated impression cylinders are constructed and arranged to place printed indicia on the same face of said web at each of said printing stations and means for maintaining registry of said printed indicia as said web travels through successive printing stations comprising a pair of rollers, a pair of arms for independently rotatably mounting each of said rollers on a common shaft to contact the nonindicia bearing surface of said web at opposite sides of said inverted .U-shaped configuration, and between a pair of spaced printing stations, the axis of said common shaft being positioned parallel to and between said impression cylinders, said mounting means for each roller including a pair of arms one end of each of which is rotatably mounted about said common shaft and the other end rotatably supporting said roller and means for individually rotating each of said rollers about said common shaft and into greater or lesser contact with said web whereby the registry of said Web is maintained between said pair of spaced printing stations.

4. The flexographic press of claim 3 wherein said means for individually rotating each of said rollers on a common shaft includes a pair of arms rotatably mounting each of said rollers to said common shaft, each pair of said arms having a worm gear fixed thereto and means to operate said worm gear including a gear, an operating shaft extending from said gear and an operating handle affixed to said shaft.

References Cited UNITED STATES PATENTS 1,643,324 9/1927 Waller 101152 1,855,525 4/1932 MacArthur 101181 X 1,959,436 5/ 1934 Marston et al. 101181 2,542,229 2/ 1951 Bojanower et al 101-182 2,570,045 10/1951 Bojanower et al. 101181 2,764.087 9/1956 Stobb 101-181 ROBERT E. PULFREY, Primary Examiner.

J. R. FISHER, Assistant Examiner.

US. Cl. X.R. 101228

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