US2902771A - Method of and apparatus for preregistering printing plates - Google Patents

Description

Sept. 8, 1959 w. H. STlCI (NEY 2,902,771

METHOD OF AND APPARATUS FOR PREREGISTERING PRINTING PLATES Filed Aug. 7, 1957 INVENTOR LOCALS ATTORNEY United States Patent O METHOD OF AND APPARATUS FOR PRE- REGISTERING PRINTlN G PLATES Wendell H. Stickney, Wilbraham, Mass., assignor to Diamond Gardner Corporation, a corporation of Delaware Application August 7, 1957, Serial No. 676,897

12 Claims. (Cl. 33--184.5)

This invention relates to methods of and apparatus for preregistering printing plates, particularly with regard to multicolor printing plates.

In conventional multicolor printing operations, wherein a composite impression is made by successively imprinting in exactly the same place from a series of printing plates each of which carries ink of a different primary color, the principal problem encountered is obtaining accurate registration of the several printing plates in order to insure that their impressions will be made in exactly the same place. Generally, such registration is achieved by a preliminary aligning operation in which equidistant reference marks or holes are placed at corresponding points on each of the plates and are so located that they will be in exact registration when the successive impressions are made in the subsequent printing operations. Heretofore, the attainment and checking of preregistration has generally been a cumbersome, expensive and time-consuming operation. Many different systems and many difierent devices have been proposed for alleviating these difficulties, but none have been entirely satisfactory.

An object of the present invention is to provide new and improved methods of and apparatus for preregistering printing plates.

Another object of the invention is to provide new and improved methods of and apparatus for accurately and rapidly attaining and checking the preregistration of a series of multicolor printing plates.

Other objects and the nature and advantages of the instant invention will be apparent from the following description taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a side elevational view of apparatus embodying the invention; with portions thereof shown in section to reveal structural details;

Fig. 2 is a transverse vertical broken section taken along the line 2-2 of Fig. 1; and

Fig. 3 is a plan view of the apparatus embodying the invention.

The apparatus illustrated is designed especially for the preregistration of arcuate printing plates of the type employed in rotary printing machines. This apparatus includes a cylinder of the proper size to receive such arcuate printing plates on its periphery, where they are mounted temporarily for the preregistration operation, as is best shown in Fig. 2 by a plate 11 mounted thereon. During this operation the position of the cylinder 10 may be adjusted both axially and rotatably between predetermined limits.

In order to facilitate accurate adjustment of the position of the cylinder 10, it is secured to a tubular cylindrical shaft 12, which is journalled slidably at opposite ends thereof in a pair of aligned sleeve bearings 14 mounted in a frame 15. A second shaft 16 extends axially through and is slidably movable within the first shaft 12. Opposite ends of the shaft 16 protrude beyond the ends of the shaft 12 and beyond the sleeve bearings 14. In fact, in Fig. 1 the righthand end of the shaft 16 has been broken away merely to simplify the drawing, and actually this shaft projects a short distance farther in this direction. A disc 18 secured to the extreme left hand end of the shaft 16, as viewed in Fig. 1, serves as a stop against one of the sleeve bearings 14 when the shaft 16 is shifted axially to the right as far as it will go. Likewise, an annulus or collar 20 mounted slidably on the shaft 16 adjacent to the disc 18 and joined to said disc by a plurality of adjustment screws 22, functions as a stop abutting the tubular shaft 12 when the shaft 16 is at the limit of its movement in this direction. On the right hand end of the shaft 16 a disc 24 and an adjacent annulus or collar 26, corresponding in structure and in function to the disc 18 and the annulus 20, are both threaded onto the shaft 16, and they are connected to each other by a plurality of adjustment screws 28. Ordinarily, the disc 24 and the annulus 26 are kept in a fully tightened position, after having centered a pair of printing plates on the cylinder 10, by rotating said disc and annulus together along the threaded end of the shaft 16 until they have advanced as far as they can go to the left, as viewed in Fig-.1. However, the disc 24 and the annulus 26 may be shifted along the shaft 16, and they may be moved relative to each other by means of the adjustment screws 28, in order to adjust the position of the cylinder 10 axially. Likewise, the adjustment screws 22 regulate the relative position of the disc 18 and the annulus 20, for controlling the axial position of the cylinder 10 and any end play thereof.

Rotational limits for the movement of the cylinder 10 are set by means of a swingable bar 30 having an elongated longitudinal slot 32 formed at one end thereof and a generally square aperture 34 extending through the opposite end thereof. The bar 30 is mounted pivotally on a horizontal shaft 36 passing through the aperture 34 and extending between opposite sides of the frame 15. The shaft 36 is journalled within a block 38 which is mounted slidably in the aperture 34 and is shiftable longitudinally of the bar 30 by means of an adjustment screw 40. A pintle 42 having a retaining head 44 on the outer end thereof projects through the slot 32 and is secured to the cylinder 10 near its periphery at. a point generally opposite to that provided for securing printing plates thereon to be preregistered. During such preregistration the cylinder 10 may be rotated for fraction of a revolution alternately in opposite directions to an extent limited by the slotted bar 30. The. pintle 42 slides from one end to the other of the slot 32 as the bar 30 pivots on the shaft 36 during the rotary motion of the cylinder 10 in each direction. By means of the adjustment screw 40 the bar 30 may be shifted with respect to the shaft 36 to limit the travel of the pin tle 42 within the slot 32, thereby controlling the limits of the rotary movement of the cylinder 10.

It is necessary to provide adjustments for insuring that the extent of the rotary movement of the cylinder 10 will be the same in each direction. In other words, the rotary limits must be set to stop the cylinder 10 at equal distances on each side of the center point of printing plates being preregistered thereon. For this of the screws 48 the shaft 36 may be shifted laterally in very small increments. V

In preregistering a series of multicolor printing plates,

or the like, the plates are compared successively in pairs" The plates are compared by observation through a pair' of optical scope viewers 54 mounted on top of the frame 15 a fixed distance apart and directly over the cylinder 10. The viewers 50 are provided internally with the usual cross-hairs (not shown) for making an accurate comparison of corresponding points on the two printing plates.

' When the printing plates are provided with screw holes for use in subsequently fastening them to the cylinder of a rotary printing machine, such screw holes are drilled into the plates while they are secured on the cylinder 10, after they have been properly centered thereon. During such drilling, opposite ends of the printing plates, such as the plate 11 (Fig. 2-), are secured to the cylinder by means of a pair of clamps 52. These clamps are arranged to hold opposite ends of the printing plates in sliding engagement until they are properly positioned, and then they may be tightened into gripping engagement by means of a plurality of screws 54. Meanwhile, the cylinder 10 is positively prevented from moving axially and rotatably by securing the shaft 12 on which it is mounted by means of a pair of set screws 56 mounted on the sleeve bearings 14. A pair of drill bushings 58 located in the top of the frame 15 and spaced apart a distance equal to the distance between the viewers 50 serve as guides for drilling the reference holes on one edge of the printing plates secured on the cylinder 10. Similarly, a second pair of drill bushings 60 positioned in the top of the frame- 15 and spaced apart the same distance, serve as drill guides for the holes on the opposite edge of the printing plates. The cylinder 10 is provided with a plurality of holes 62 on its periphery corresponding to the positions of the bushings 58 and 60, for allowing the drill to penetrate entirely through the printing plates.

Before using the above-described apparatus for pre-.. registering a series of printing plates, the apparatus should be checked tobe sure that all the various. adjustment screws are properly set, and particularly to have the cylinder 10 properly centered. The, disc 24 and the. an.

nulus 26 are tightened, and adjustments are made to eliminate any end play of the shafts 12. and 16011 which till? cylinder 10 is mounted. The cross-hairs of the viewers 50 should appear coincident with a pair of center marks (not shown) formed at the midpoints of the two;

placements or positions provided onthe periphery of the cylinder 10 for the receptionof a pair of printing plates to be preregistered. Finally, the rotational limits of the cylinder 10 are checked to be certain that it is rotatable equal distances on opposite sides of the center marks.

Printing plates may be preregistered on this apparatus;- bya rapid, simple, substantially fool-proof method with superior accuracy. First, one printing plate is centered with respect to; one of the viewers 50. To do. so, the plate is placed on the cylinderltl and its ends are slidably engagedfby the pairof clamps 52. The disc 24 and the annulus or collar 26 are loosened and shifted to the right along the shaft 16 to allow the shaft 12. and the cylinder 10,carried thereon to move axially to the right a distance corresponding approximately to one-half the width. of the printing plate 11,untilone edge of the. plate 11 appears. in the field of vision of one of the viewers 50, then. the cylinder 1-0 is shifted axially in the opposite direction until. the opposite edge of the platel-lv is visible underthe sameviewer, and the cylinder-10 is moved. axially back and. forth while adjusting the position of'the stop, means at opposite ends thereof, such as the disc 2'4 andthe annulus. 26, to limit the axial, movement, of the shaft 12, and if; necessary. the printing plate is. shifted,

until it appears accurately centered. Now the disc 24.

and the annulus26 are tightened to prevent any further axial. movement of the shaft 12. ThQ Li-h? y nder 0 is rotated back and forth while viewing one edge of the printing plate 11 and adjustments are made to insure that this plate is not askew and to cause opposite ends of the printing plate to appear in the viewer 50 at the rotational limits of the cylinder 10. Having been thus properly centered, the printing plate is securely clamped to the cylinder 10 by tightening the screws 54 of the clamps 52.

In preparation for the drilling of reference holes in the printing plate, the cylinder 10 is,moved to bring the holes 62 therein which are not covered by this printing. plate on one side of the cylinder 10 into alignment with the bushings 58 and 60 which are located in the top of the frame 15. A dowel (not shown) may be used to align one of the bushings 58 or 60, as the case may be, with one of the holes 62 on one side of the cylinder 10, while the corresponding bushing on the other side is being used as a guide for drilling a hole through the printing plate. During this drilling. operation the set screws 56 are tightened to secure the shaft 12 and the cylinder 10 carried thereon against movement. In this manner holes may be drilled on both sides of the printing plate through the bushings 58 and 60;,

Next, a second printing plate (not shown) is mounted beside the drilled first plate on the other half of the cylinder 1%, and this plate is centered with respect to the other viewer 50 and clamped in the same manner as was done for-the first plate. It is important to have identically correspond-ing points on the two plates appear on the cross-hairs ofthe two viewers 50. Reference holes are their drilled in the second plate, using the bushings 58' and 60 as drilling guides, and usinga dowel to locate corresponding drilled holes in the first plate. These two drilled printing plates should: now be perfect duplicates, thereby being perfectly preregistered. The other plates of the'seri'es may theneach be paired successively with one of the previously drilled plates'for drilling in thesame manner, thus preregistering the whole series of printing plates.

It is evident that the above-described apparatus andmethod provide for the preregistration of printing plates with a'minimum of? time, expense, preparation and skill on the part 'of the operator. Yet, a. high standard. of accuracy exists, and any plate defects'can be readily deteetedj It is also possible to; check the cylinders of rotar y printing machines on this apparatus. Plate harndlingt i greatly minimized, and the operating procedure is quite simple. By minimizing the. number of operating stepsrequired in the whole, procedure, the sources of both human} and; machine errors are greatly reduced.

Although: the invention has been described and. illus-- trated with particular reference to the preregistration of curvedprinting plates: made for-use on rotary printing machines, it should be understood that the principles. of, the

invention may also be applied advantageously inthe: case of fiat printing plates. In; suchcase the flat plates may be shifted back and forth laterally and axially in the same horizontal. planebetween predetermined limits. While the inventon is especially useful for a series of color printing plates, other types of printing plates may be preregistered thereby withsimilar success. Furthermore, while it is preferred to; form-corresponding reference points. in. the plates by. drilling holes therethrough, it is contemplated. that such. reference points may be. formedby merely. punching or otherwise marking the plates.

Itwillbe obvious tothose skilled. in: the art that various changes. may be made without departing from the spirit of theinVenfiOn, and. therefore the invention is not limited. to what is shown in the drawings and described. in. the specification, but only as indicatedin the appended. claims.

What is claimedisz.

1. Apparatus for preregistering a series. of printing plates, comprising a cylindrical. support 'for receiving on. its periphery a pair of printing; plates in side-by-sidere; lation, clamping meansfor secur-ingthe plates tothe'support while permitting; adjustments of their positionthere:

on, a frame in which said support is mounted for normal plates, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, an axial shaft secured to the cylinder, a frame slidably supporting the shaft for normal movement axially and rotatably, stop means for limiting the axial movement of the shaft to limit such movement of the cylinder, means for stopping the rotary movement of the cylinder at predetermined maximum limits, a pair of optical viewers mounted a fixed distance apart on the frame above the positions where the printing plates are clamped, and a pair of guides located on the frame the same distance apart as the viewers for locating corresponding points of reference on the plates.

3. Apparatus for preregistering a series of printing plates, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, a shaft extending axially through said cylinder and secured thereto, a frame having a pair of bearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, stop means for limiting the axial movement of the shaft to limit such movement of the cylinder, means for stopping the rotary movement of the cylinder at predetermined maximum limits, a pair of optical viewers mounted a fixed distance apart on the frame above the positions where the printing plates are clamped, and a pair of guides located on the frame the same distance apart as the viewers for locating corresponding points of reference on the plates.

4. Apparatus for preregistering a series of printing plates, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, a shaft extending axially through said cylinder and secured thereto, a frame having a pair of hearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, a pair of adjustable stops mounted at opposite ends of the shaft for limiting its axial movement to limit such movement of the cylinder, stop means linking the cylinder to the frame for halting the rotary movement of the cylinder at predetermined maximum limits equally spaced in opposite directions from the center points of printing plates being preregistered thereon, a pair of optical viewers mounted a fixed distance apart on the frame above the positions where the printing plates are clamped, and a pair of guides located on the frame the same distance apart as the viewers for locating corresponding points of reference on the plates.

5. Apparatus for preregistering a series of printing plates, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means forsecuring the plates to the cylinder while permitting adjustments of their position thereon, a shaft extending axially through said cylinder and secured thereto, a frame having a pair of sleeve hearings in which said shaft is journalled for rotation and inwhich said shaft is axially slidable, a pair of adjustable stops mounted at opposite ends of the shaft for limiting its axial movement to limit such movement of the cylinder, a swingable arm pivotally linking the cylinder to the frame for halting the rotary movement of the cylinder at pre- G determined maximum limits equally spaced in opposite directions from the center points of printing plates being preregistered thereon, a pair of optical viewers mounted a fixed distance apart on the frame above the positions where the printing plates are clamped, and a pair of guides located on the frame the same distance apart as the viewers for locating corresponding points of reference on the plates.

6. Apparauts for preregistering a series of curved printing plates to prepare them for use on a rotary printing machine, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-byside relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, a shaft extending axially through said cylinder and secured thereto, a frame having a pair of sleeve bearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, a pair of adjustable stops mounted at opposite ends of the shaft for limiting its axial movement to limit such movement of the cyl inder, a swingable arm mounted pivotally with respect to the frame for linking the cylinder tlhereto to halt the rotary movement of the cylinder at predetermined maximum limits equally spaced in opposite directions from the center points of printing plates being preregistered thereon, said arm having a longitudinal slot in which a pintle secured to the cylinder is free to travel back and forth during alternate rotary movement of the cylinder, a pair of optical viewers mounted a fixed distance apart on the frame above the positions Where the printing plates are clamped, and a pair of guides located on the top "of the frame and mounted the same distance apart as the Viewers for locating corresponding points of ref erence on the plates.

7. Apparatus for preregistering a series of curved printing plates to prepare them for use on a rotary printing machine, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-byside relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, a shaft extending axially through said cylinder and secured thereto, a frame having a pair of sleeve hearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, a pair of adjustable stops mounted at opposite ends of the shaft for limiting its axial movement to limit such movement of the cylinder, a swingable arm mounted pivotally with respect to the frame for linking the cylinder thereto to halt the rotary movement of the cylinder at predetermined maximum lirnits, said arm having at one end there-' of an elongated longitudinal slot in which a pintle secured to the cylinder is free to travel back and forth during alternate rotary movement of the cylinder, the other end of said arm being mounted pivotally on a shaft car ried by theframe, means for adjusting the position of the arm on said last-mentioned shaft for controlling the rotary motion of the cylinder to set its rotational limits at equal distances in opposite directions from the center points of printing plates being preregistered thereon, a pair of optical viewers mounted a fixed distance apart on the frame above the positions where the printing plates are clamped, and a pair of guides located on the top of the frame and mounted the same distance apart as the viewers for locating corresponding points of reference on the plates. 7

8. Apparatus for preregistering a series of .curved printing plates to prepare them for use on a rotary printing machine, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon a Shaft on which said cylinder is secured for rotary movement, a frame having a pair of sleeve bearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, a pail.

of adjustable stops mountedv at opposite ends of the shaft for limiting its axial movement to limit such movement of the cylinder, at swingable arm. mounted pivotally' with respect to the frame for linking the cylinder thereto to halt the rotary movement of the cylinder at predetermined maximum limits. in opposite directions, said arm having at; one end thereof an elongated longitudinal slot in which a pintle secured to the cylinder is. free to. travel, back and forth during alternate rotary movement of the cylinder, the other end of said arm having an aperture in which a block is. slidable longitudinally of the-arm, a shaft journalled in the block and supported by the frame for pivotally mounting this end of the swingable arm, means for adjusting the position of the block within the aperture for controlling the extent of the rotary motion of the cylinder, means for adjusting the mounting of the last-mentioned shaft on the frame to set the rotational limits of the cylinder at equal distances in opposite directions from the center points of printing plates being preregistered thereon, a pair of optical viewers mounted a fixed distance apart on the top of the frame above the positions where the printing plates are clamped, and a pair of guides located on the top of the frame and mounted the same distance apart as the viewers for locating corresponding points of reference on the plates.

9. Apparatus for preregistering a series of curved printing plates to prepare them for use on a rotary printing machine, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in side-by-side relation, clamping means for securing the plates to the cylinder while permitting adjustments of their position thereon, a first shaft on which said cylinder is secured for rotary movement, a frame having a pair of sleeve bearings in which said shaft is journalled for rotation and in which said shaft is axially slidable, a second shaft extending axially through the center of the first shaft and protruding beyond the sleeve bearings, a pair of adjustable stops mounted at opposite ends of the second shaft for limiting its axial movement to limit such movement of the cylinder, a third shaft secured adjustably to the frame, a swingab-le arm linking the cylinder to the third shaft, said arm having at one end thereof an elongated longitudinal slot in which a pintle secured to the cylinder near the periphery thereof is free to travel between opposite ends of the slot during rotary movement of the cylinder alternately in opposite directions thereby halting its rotary movement at predetermined maximum limits, the other end of said arm having an aperture extending therethrough, a block journalled on the third shaft and mounted slidably in said aperture for movement longitudinally of the arm, an adjustment screw for regulating the position of the block within the aperture thereby to control the extent of the rotary movement of the cylinder, means for adjusting the position of the third shaft on the frame to set the rotational limits of the cylinder at equal distances in opposite directions from the center points of printing plates being preregistered thereon, a pair of optical viewers mounted a fixed distance apart on the top of the frame above the positions wherev the printing plates are clamped, and. a pair of guides located on the top of the frame and mounted the same distance apart. as the viewers for locating corresponding points of reference on the. plates.

10. Apparatus for preregistering a series of curved printing plates to prepare them for use on a rotary printing machine, comprising a supporting cylinder for receiving on its periphery a pair of printing plates in sideby-side, relation, a plurality of clamps for securing the plates to the cylinder at their edges while permitting adjustments of their position thereon, a first shaft on which said cylinder is secured for rotary movement, a frame having a pair of sleeve hearings in which said shaft is secured at opposite ends thereof to the frame and having eccentricbushings formed in said ends,,a swingable-arm' linking the cylinder to they third shaft, said arm having: an elongated longitudinal. slot: formed. in one. end thereof and. having an aperture. extending through its other end,

a pintlesecured. to the cylinder near the periphery thereof and mounted in the slot for slidable movement between; opposite ends thereof during rotary. movement; of the. cylinder alternately inopposite directions thereby halting: itstrotary movement at predetermined maximum limits, a; block journalled on the third shaft and mounted slidablyr in said aperture for movement longitudinally of the arm, means. for regulating the position of the block Within the. aperture thereby to control the. extent. of the rotary movementof the cylinder, a. pair of adjustment screws mounted in the eccentric bushings at opposite ends ofthe third shaft 'for adjusting its position on the frame to set the rotational limits. of the cylinder at equal distances in. opposite directions from the center points of printing plates; being preregistered thereon, a pair of optical viewers: mounted a fixed distance apart-on the top of the frameabove. the positions where the printing plates are clamped, a plurality of pairs of marking guides located. on the. top of the frameand. mounted the. same distance apart; as the. viewers for locating corresponding Points, of reference on the plates, and means for securing the cylinder againstmovement while the plates thereon are being marked.v

11. A method of preregistering a series of printing: plates,.comprising. the steps of centering one of. said plates with respect to. one of a plurality of marking guides spaced a fixed distance apart, marking said plate with a set of reference marks spaced apart said fixed distance, centering a second one of said plates. with. respect to a second one. of said guides which is spaced said fixed distance fromthe first-mentioned guide, marking said second plate with a set of reference marks corresponding to and guided by the marks. on the first plate, and successively pairing,

each of. the remaining plates with one of the previouslymarked. plates to locate sets of reference marks at corresponding positions thereon.

12. A'method. of preregistering a series of printingplates, comprising the steps of placinga first one of said plates; upon an adjustable support having a plurality of marking guides spaced at fixed distance apart, centering said plate with respect to one of said guides, marking said plate with a. set of reference marks spaced apart said. fixed distance, placing a second one of said plates on said support adjacent to the first-mentioned plate, centering said second plate with respect to a second one of said guides which is spaced said fixed distance from the firstmentioned guide, marking said second plate with a set of reference marks corresponding to and guided by the marks on. the first plate, and successively pairing each of the remaining plates with one of the previously marked plates to locate sets of reference marks at corresponding positions thereon.

References Cited in the file of this patent UNITED STATES PATENTS.

1,800,209 Christopherson Apr. 14, 1931 2,680,405 Faeber et a1. June 8, 1954 2,688,803. 7 .Huck Sept. 14, 1954 2,689,411 Huck Sept. 21, 1954

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