US3049996A - Rotary printing press - Google Patents

Description

Aug. 21, 1962 R. H. DOWNIE 3,049,996

ROTARY PRINTING PRESS Filed April 25, 1958 INVENTOR. ROBERT H. DOWN/E A To NEY Mac a AGENT United States Patent 3,049,996 ROTARY PRINTING PRESS Robert H. Downie, Menasha, Wis., assignor, by mesnc assignments, to Harris-Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed Apr. 25, 1958, Ser. No. 730,959 6 Claims. (Cl. 101-217) This invention relates to relief or typographic printing in which raised surfaces of the plates or other members making up the printing form are inked and thereafter placed in contact with print receiving material to transfer an imprint to the material in the form of an inked image.

In the customary practice of relief printing, the printing form is made up of What may be called image portions and non-image portions, i.e. printing areas and non-printing areas, respectively. The image portions comprise all those areas which are type high, that is, which are in the image plane relative to the support member carrying the form, whether the support member be a fiat bed as in flat bed presses or a cylinder as in rotary presses. The nonimage portions of such a form comprise all those areas which are below type-high, and these areas may be between letters, the areas between dots of a half-tone plate, or merely areas between plates or other members comprising the overall form.

When such a form is inked in the customary manner, ink is applied by a series of friction-driven rollers of relatively small diameter which pass over the entire form and contact only the areas thereof which are in the image plane, placing a deposit of ink on all such areas, all non-image areas having been cut away to a depth very substantially below the image plane. Then when print-receiving material is pressed against the inked form, the material receives an imprint from all the image or type-high areas, which are only those areas intended to reproduce an image on the material.

Since the small diameter inking rollers are frictiondriven and run on a relief surface of the plate which normally presents irregularly spaced image producing areas of varying size, the contact between the plate and the inking rollers is irregular and of uneven pressure. The combination of irregular contact, uneven pressure and frictiondriven rollers tends to force ink down the sides of some or all of the relief areas, resulting in a slurred or blurry image and in incomplete replenishment of ink. Furthermore, the uneven pressure tends to deposit too thin a film of ink on certain of the relief areas, even while applying so much ink to other areas that the excess is squeezed over the edges and down the sides of the relief areas.

In order to prevent these small, friction-driven inking rollers from applying ink to the non-image areas of the plate, the degree of relief must be very substantial, between 0.035 in. to 0.065 in. being customary. This degree of relief is obtained either by mechanicallyv routing the non-image areas, or by an extra deep etch bath in the shoulderless etching processes. It is obvious that both of these expedients are expensive in labor and/ or etching chemicals and, in addition, require that the original plate be of a very substantial thickness in order that the nonimage areas of the finished plate remain of 'sufficient thickmess to give strength to the plate after the relief depth requirements have been met. As a result, thick, bulky plates requiring an excessive amount of material are necessary. The plates, which after formation of the image portions thereon are curved to conform to the curvature of the plate-bearing cylinder upon which they are to be mounted, must be fairly limited in area in order to avoid excessive distortion of the image portion when the plates are curved.

The present invention provides for a substantial improvement in the direct typographic printing art by providing a method for obtaining cleaner, sharper printed images 3,049,996 Patented Aug. 21, 1962 ice free of slurring and spotting and by permitting economies realized through the use of thin, wraparound printing plates of essentially unlimited area having a very shallow etch.

These and other benefits which will be later described are obtained by a unique inking system in a preferred embodiment of which there is interposed between the ink distributing rollers and the plate cylinder an inking cylinder which is maintained in precise relationship to the plate cylinder by bearers on the ends of the inking cylinder which contact similar bearers on the ends of the plate cylinder. The precise setting of these cylinders is accom-' plished by precision grinding of the cylinders and bearers and, once mounted in position in the press, the subsequent contact between the inking cylinder and the relief surface of the printing plate borne on the plate cylinder is controlled by the bearer relationship between the inking cylinder bearers and the plate cylinder bearers and. remains constant for the life of the inking cylinder. The inking cylinder is preferably power driven at a peripheral speed equal to that of the plate cylinder to further reduce slurring.

l have found that the advantages described above may be realized with inking cylinders of various diameters, and have determined that additional advantages ensue when the inking cylinder and the plate cylinder are commensurate in diameter so that each spot on the plate cylinder is inked by the same spot on the commensurate inking cylinder at each impression revolution of theplate cylinder.

My invention may be most readily understood by reading the following descriptive specification in connection with the accompanying drawings in which FIGURE 1 is a schematic side view representation, partially in cross-section, of the inking and printing portions of a one-color rotary press, showing the arrangement of l the rollers and cylinders involved in the present invention,

FIGURE 2 is a schematic view from the end of the press, showing the plate and inking cylinders and bearers and, in cross-section, portions of the printing plate and inking blanket,

FIGURE 3 is a schematic view from the side of the press of a portion of the press showing the adjusting mechanism for bringing the inking and plate cylinders into proper impression relationship, the press being on impression at this stage, and v FIGURE 4 is a view similar to FIGURE 3 except that the press is illustrated in the oif-impression state.

FIGURE 1 illustrates the preferred form of relief printing machine, suitable for imprinting of a single color upon a print receiving material, adapted to incorporate the present invention. For the imprinting of additional colors, duplicates of pertinent parts of the equipment are conventionally grouped together with the single color equipment illustrated. The machine in p the preferred embodiment includes a series of conventional inking rollers 10, particularly adapted to receive the ink from'an ink fountain (not shown), distribute the ink evenly across the length of the rolls and apply it'to the inking cylinder, generally indicated by the number 11. The inking cylinder of this invention comprises a conventional base cylinder 12 with bearers 13 (more clearly shown in FIG- URE 2). About the base cylinder 12. is wrapped a replaceable blanket 14 of a resilient rubber or rubber-like material. The ends of the inking blanket are gripped by conventional elements 15 aflixed to the base cylinder 12. The ink fro-m rolls 10 is transferred to the exterior surface of the resilient blanket as will be described in detail later herein.

Blanket 14 transfers the ink to a plate cylinder generally indicated by 16, which includes a base cylinder 17 and a printing plate 18 which is fastened to cylinder 17 by conventional gripping elements 19. The printing plate 18 bears on its surface raised images of the work to be reproduced upon a print-receiving material. The plate cylinder is also equipped with bearer 20 (more clearly shown in FIGURE 2). In the preferred embodiment of my invention'illustrated in the. figures, inking and plate cylinders 11 and 16 are of the same diameter and are concomitantly driven so that they run in a one-to-one relationship and are positioned and maintained in a precise relationship to each other by the bearers 13 and 20 on each end of the inking and plate cylinders, respectively. a The inking and plate cylinders are journalled in a suitable press frame (not shown) and the journals of at least one of these cylinders should be adjustable so that the cylinders may be brought into the initial precise adjustment which is subsequently maintained by the bearer relationship. Referring toFIGURES 3 and 4, a typical embodiment is shown in which the main shaft 23 of the plate cylinder 16 is carried in an eccentric bearing 24 secured 'in a yoke 26 pivotally attached to a connecting rod 28. The connecting rod 28 is adjustable in its effective length by a conventional threaded arrangement for obtaining the fine adjustment desired in the relationship between the inking and plate cylinders. The connecting rod 28, at its end remote from the yoke 26, is attached to and is actuated by any suitable pressure applying means (not shown) such as a mechanical linkage, an air cylinder, a solenoid or the like, which may shift the various elements from the on-impression position of FIGURE 3 to the off-impression position of FIGURE 4 and vice versa.

The pressure applied in the on-impression position should be sufficient to maintain positive bearer contact under all normal press operating conditions but safety features are normally incorporated for release of such pressure in case of accidental ball-up so that press damage may be avoided. The bearers 13 and 20 are so dimensioned that when the inking and plate cylinders are brought into bearer contact by the aforementioned applied pressure, the resilient inking blanket is held under very slight compression at the line of contact with the printing plates. The plate and/or inking cylinder may be constructed to accommodate whatever packing may be necessary to compensate for irregularities in plate thickness or cylinder diameter, although such packing is generally unnecessary if the thin, shallow-etched wraparound printing plates hereinafter described are utilized and if the bearer relationship is precisely maintained.

The bearers are preferably mounted as close as possible to the printing area without actually encroaching thereon. In a suitable embodiment, the bearers comprise hardened steel collars sweated on the ends of the inking and plate cylinders, precision ground and adjusted so that when pressure is applied to attain and maintain bearer contact, the resilient inking blanket 14 is compressed by no more than a few thousandths of an inch at the time of contact with the printing plate. That is, the blanket 14, under no compression load, presents a surface very slightly higher than the inking cylinder bearers 13, as shown in FIGURE 2 at point A. Under impression, with bearer contact, the blanket surface is compressed to be flush with bearers 13. In the printing .press herein described, the amount of compression is nor- .mally about 0.001 inch to 0.002 inch, and preferably should not exceed 0.003 inch to 0.005 inch if the thin, shallow-etched, wraparound printing plates previously mentioned are employed.

, The image is reproduced by passing a sheet such as indicated at 30 between the nip of cylinder 16 and impression or back-up cylinder 31. The sheet material may be conventionally fed in timed relationship from a stack 32 thereof by such as feeding rolls 33, which carry the sheets individually from the stack onto a conveyor support 34, from which they are grasped by conventional gripping fingers 35 mounted on impression cylinder 31. The sheets are then carried through the nip of counterrotating cylinders 16 and 31, at which point they receive the ink impression from the image on plate 18. As the sheets pass through this nip, they are conventionally fed to a conveyor such as indicated at 36, by which they may be carried through a drying zone and/or for stacking or further disposition. As previously suggested, additional banks of printing equipment may be supplied in duplication of that just described, through which the sheets may be consecutively passed to receive further ink impressions.

It is to be understood that my invention is not to be limited to the preferred embodiment illustrated in the accompanying drawings, since various modifications thereof may be made without departing from the spirit of my invention. For example, the major advantages of my invention may be realized with inking cylinders or rollers of various diameters maintained in precise relationship to the plate cylinder by bearers such as those previously described. The only limitation on inking cylinder size is that it be sufficiently large to have the necessary strength and rigidity to maintain the precise bearerestahlished relationship along the entire line of contact between the inking cylinder and the printing plate Without bowing or distortion under operating conditions. If inking cylinder diameter is appreciably smaller than the plate cylinder diameter, a series of two or more bearerequipped cylinders may be used rather than a single inking cylinder as illustrated. If more than one inking cylinder is used, each such cylinder must be maintained in precise relationship to the plate cylinder by bearers, as previously described.

If the diameter of the inking cylinder is such that it does not revolve commensurate with the plate cylinder, the resilient surface of the inking cylinder should be continuous rather than in the form of a removable blanket as previously described.

Since the contact between the inking cylinder and the plate cylinder is very precisely adjusted and maintained in perfect adjustment by the bearer relationship, the pressure of contact between these cylinders is constant throughout the life of the inking cylinder. No individual adjustments are necessary to compensate for different printing plates and plates may therefore be changed with no necessity for individual press cylinder adjustments. The precise control of contact and contact pressure also permit the use of plates having an extremely shallow relief, an etch depth of from 0.002 inch to 0.010 inch being quite satisfactory, and the term extremely shallow relief as used herein is to be understood as referring to relief of the order of this range. Such shallow etchings are possible because my invention results in such excellent rebalancing of ink on the inking cylinder and such precise control of ink placement that the pressure on the inking cylinder need not be so great as to force ink down the sides of even such a shallow relief as 0.002 inch. Even with such a very shallow relief, there is no slurring or spotting due to ink being forced down into non-image areas of the plate. Printing is therefore cleaner and sharper.

Since by the use of my invention, a very shallow etch may be used, the plates may be made much thinner than those conventionally in use, with proportionately reduced expense. The shallow-etched plates require no mechanical routing or chemical deepening, thus effecting further economies. Plate thicknesses ranging from 0.010 inch to 0.025 inch are quite satisfactory and due to their lightness, flexibility and low image distortion on bending, such plates may be made of an area sufiiciently large to cover the largest commercially available printing press roller. These large, light, thin, one piece, wraparound, shallowetched printing plates are very rapidly mounted and exchanged and, of course, perfect relative register is maintained between the various printing areas since the plate is an integral unit with no possible movement between the relative sections of the plate. This integral register of various portions of the plate further reduces makeready time and labor.

The combination of large, thin, shallow-etched plates having perfect integral register together with the freedom from the individual inking roller pressure adjustments previously necessary to compensate for individual plate variations are made possible only by the precise inking cylinder to plate cylinder contact maintained by the bearer relationship previously discussed. These characteristics resulting from the practice of my invention result in sharp, clean printing with less plate Wear since the plate is held under constant, optimum, even pressure and is not subject to the wear resulting from the conventional friction-driven inking rollers. They also give to typographic or relief printing the historically rapid makeready of the offset press.

Recovering of the single inking cylinder is more practical and economical than with the orthodox multiplicity of friction-driven inking rollers.

I have found that the above advantages are obtained through a range of bearer-equipped inking cylinder diameters. However, a commensurate relationship between the plate cylinder diameter and the inking cylinder diameter has been found to offer certain additional advantages.

The use of an inking cylinder equal in diameter to the plate cylinder eliminates ghosting. Ghosting results from incomplete replenishment of ink on an inking roller and subsequent placement of the incompletely replenished area design on another portion of the design. Ghosting is impossible with the commensurate inking system as shown in the preferred embodiment of my invention since each spot on the plate cylinder is always inked by the same spot on the inking cylinder. The synchronous nature of commensurate inking also assists in the elimination of slurn'ng normally experienced by orthodox friction-driven inking rollers, resulting in a cleaner impression.

Diiferential inking, as described in my co-pending application, Serial No. 700,877 filed December 5, 1957, of which the present application is a continuation in part, is possible using the commensurate inking system of the present invention. Specific spot inking is also made practicable by a commensurate inking system.

In view of the many other variations possible without departing from the spirit of my invention, it is to be understood that no limitations thereon are intended except as specifically set forth in the following claims.

I claim:

1. A rotary relief type printing press comprising the combination of a rigid inking cylinder having a relatively thin resilient inking member extending over at least a predetermined fraction of the total surface of said cylinder, means operative to apply a coat of printing ink to the surface of said inking member, a plate cylinder extending parallel to and adjacent said inking cylinder, means on said plate cylinder for mounting an extremely shallow relief printing plate on a predetermined portion of the surface thereof, said plate cylinder and said inking cylinder being of such related diameters and said inking member and said plate mounting means being so dimensionally related that the same areas of the plate are always linked by the same areas of said inking member, bearers on the ends of each said cylinders adapted to run in contact under pressure during normal printing operation of said press to c ntrol the contact pressure between said inking member and the plate, said inking cylinder and plate cylinder each having sufficient strength and rigidity to maintain their positional relationship as determined by said bearers along the entire line of contact between said inking member and the plate maintaining compression of said inking member within a maximum of approximately 0.005 inch and thus sutficiently less than the relief of the plate in larger non-image areas thereof to prevent transfer of ink to such relieved non-image areas, means operative to drive each of said cylinders in counter-rotation to the other and at essentially equal peripheral speeds preventing relative movement between contacting portions of said inking member and the plate, and means including an impression member operable to bring print receiving material into contact with the inked plate to transfer an ink image directly from the plate to the material.

2. A printing press comprising the combination of an inking cylinder having a resilient inking member extending over at least a predetermined fraction of the total surface of said cylinder, means operative to apply printing ink to said inking member, a plate cylinder extending parallel to and adjacent said inking cylinder, means. on said plate cylinder for mounting a relief printing plate, a flexible shallow-relief printing plate of material essentially incompressible relative to said inking member mounted on said plate :cylinder and maintained in position thereon by said mounting means, bearers on the ends of each of said cylinders aligned to run in continuous contact under pressure during normal printing operation of said press to control the contact pressure between said inking member and said plate, said plate and/or said inking member being so mounted that its surface extends outwardly beyond the periphery of the bearers on its associated cylinder causing a predetermined interference of said plate and said inking member and causing compression said inking member against said plate within -a maximum of approximately 0.005 inch, said inking cylinder and plate cylinder each having sufficient strength and rigidity to maintain their positional relationship as determined by said bearers along the entire line of contact between said inking member and said plate, means operative to drive each of said cylinders in counter-rotation to the other and at essentially equal peripheral speeds preventing relative movement between the surface of said inking member and said plate at the instantaneous line of contact therebetween, said plate and said inking member being of such related peripheral dimensions that the same areas of said plate and said inking member always meet at said line of contact, and impression means arranged to transfer an ink image directly from said plate to print receiving material.

3. A printing press as defined in claim 2 wherein said resilient inking member is a removable resilient blanket, and means on said inking cylinder providing for mounting of said blanket thereon.

4. A rotary relieftype printing press comprising the combination of a rigid inking cylinder having a relatively thin resilient inking member extending over at least a predetermined fraction of the total surface of said cylinder, means operative to apply a coating of printing ink over substantially the entire said inking surface, a plate cylinder extending parallel toand adjacent said inking cylinder and having means for mounting a flexible shallowrelief printing plate on a predetermined portion of the surface thereof, said cylinders being of essentially the same diameter, bearers on the ends of each of said cylinders adapted to run in continuous contact under pressure during normal printing operation of said press to control the contact pressure between said inking member and the plate, said inking cylinder and plate cylinder each having sufiicient strength and rigidity to maintain the precise relationship along the entire line of contact between said inking member and the plate as established by said bearers maintaining compression of said inking member within a maximum of approximately 0.005 inch, means operative to drive each of said cylinders in counterrotation to the other and at essentially equal peripheral speeds preventing relative movement between said inking member and the plate at the instantaneous line of contact thereb-etween, an impression cylinder mounted to extend adjacent said plate cylinder and adapted to define therewith a nip through which print receiving mate- 'Y rial is carriedvon said impression cylinder in contacting and ink transferring relation to the inked plate, and means driving said impression cylinder at a peripheral speed essentially equal to the peripheral speed of said plate cylinder.

5. A rotary printing press adapted particularly for print ing from relief printing surfaces upon sheets of print receiving material, comprising the combination of three cylinders mounted in adjacent relation with their respective axes of rotation parallel, drive means for each of said cylinders cooperating to rotate said cylinders in counterrotation with respect tothe adjacent cylinder and at essentially equal peripheral speeds, a relatively thin resilient inking member on the surface of the first of said cylinders providing a compressible inking surface, means operative to apply a coating of printing ink to the entire surface of said inking member, means on the second of said cylinders for mounting a flexible essentially incompressible shallow-relief printing plate on at least a portion of the surface thereof, bearer means maintaining the cooperating surfaces of said first and second cylinders in precisely spaced and parallel relation during normal printing operation of said press, said first cylinder and said second cylinder each having sufiicient strength and rigidity to control the compression of said inking member uniformly along the entire line of contact thereof with the plate as established by said bearer means within a of approximately 0.005 inch, means on said third cylinder for carrying sheets of print receiving materi-al through a printing nip between said second and third cylinders to press the material into contact with the inked surface of a plate mounted on said second cylinder to transfer an ink image directly from the plate to the material, said first and second cylinders being of such relative diameters and said plate mounting means being so dimensionally related With respect to said inking member that the same areas of said inking member always come into contact with the same corresponding areas of the plate, means for feeding sheets of print receiving material into contact with said sheet carrying means at a fixed location about the periphery of said third cylinder, and delivery means adapted to receive the printed material from said third cylinder .and to carry said printed material to a delivery station.

6. A printing press adapted for letterpress printing from plates having shallow relief, comprising a printing member having means for mounting thereon a shallow relief printing plate, impression means cooperating with said printing member to bring print receiving material into contact with a plate mounted on said printing member for transfer of an inked image directly from the plate to such material, a rigid inking cylinder mounted adjacent said printing member and having a relatively thin resilient inking member extending over at least a predetermined fraction of the total surface of said cylinder corresponding to the maximum size plate mountable on said printing member, said inking cylinder being of such diameter with respect to such maximum size plate that the same areas of the plate are always inked by the same areas of said inking member, means operative to apply a coating of printing ink to the surface of said inking member for transfer to the plate, bearer means on said inking cylinder and said printing member cooperating to run in contact under pressure during normal printing operation of said press controlling the contact pressure between said inking member and the plate, said inking cylinder having sufiicient strength and rigidity to maintain a relatively slight compression of said inking member at the instantaneous line of contact between the plate and said inking member within a maximum of approximately 0.005 inch for transfer of ink only to the non-relieved image areas of the plate, and means operative to drive said printing member and said inking cylinder at essentially equal surface speeds preventing relative movement between contacting portions of said inking member and the plate at the instantaneous line of contact therebetween.

References Cited in the file of this patent UNITED STATES PATENTS 160,947 Palmer et a1 Mar. 16, 1875 654,268 Millison July 24, 1900 935,907 Harris Oct. 5, 1909 978,839 Bremer et al Dec. 20, 1910 1,095,833 Fenner May 5, 1914 2,294,879 Affelder Sept. 8, 1942 2,362,069 Huck Nov. 7, 1944 2,447,991 Stempel Aug. 24, 1948 2,778,305 Gottscho et al Jan. 22, 1957' 2,853,003 Kaldschmidt et al Sept. 23, 1958 FOREIGN PATENTS 305,216 Great Britain Apr. 24, 1930 720,964 Germany Mar. 20, 1942 OTHER REFERENCES Commercial Engraving and Printing (Hackleman), published by Commercial Engraving Publishing Co. (Indianapolis, 192, page 338 relied on. (Copy to be found in Div. 17.)

Thiokol Facts, volume 1, Number 2, published by Thiokol Corp, Aug. 8, 1936, copy to be found in Div. 17.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 049396 August 21 1962 Robert H. Downie It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3 line 2, for "bearer" read bearers line 55 for time" read line 3 column 5, line 17, for "Recovering" read Re-covering line 64 for "linked" read inked column 6 line 29 after "compression" insert of column 8, line 48, for "192" read 1921 Signed and sealed this 11th day of December 19629 (SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents

Images