US3126826A

US3126826A - Transfer cylinder for rotary multi-color printing presses

Info

Publication number: US3126826A
Authority: US
Publication date: 1964-03-31
Anticipated expiration: 1981-03-31

Description

H. FISCHER March 31, 1964 TRANSFER CYLINDER FOR ROTARY MULTI-COLOR PRINTING PRESSES Filed Dec. 12, 1960 2 Sheets-Sheet 1 TNUENTUR...

H- FlSCHER March 31, 1964 TRANSFER CYLINDER FOR ROTARY MULTI-COLOR PRINTING PRESSES Filed Dec. 12, 1960 2 Sheets-Sheet 2 5 I am 3 A n" United States Patent 3,126,826 TRANSFER CYLINDER FOR ROTARY MULTI- COLOR PRINTING PRESSES Herman Fischer, Augsburg, Germany, assignor to Maschinenfabrik Augshurg-Nnrnberg, A.G., a corporation of Germany Filed Dec. 12, 1960, Ser. No. 75,325 Claims priority, application Germany Dec. 28, 1959 9 Claims. (Cl. 101-424)) This invention relates to a transfer cylinder for transferring printed sheets from one printing station to the next in a multi-color printing press where the transfer means contacts or engages the printed surface of the sheet before the ink image thereon is set to a non-smearing condition, and, more particularly, to such transfer cylinders having an axially continuous outer working surface with spacer means adjustably positioned over the working surface of the cylinder for contacting the printed surface of the sheet only in non-inked areas thereof and/ or otherwise separating inked areas of the printed sheet from direct or smearing contact with the surface of the transfer cylinder during transfer of the printed sheet from one printing station to another.

As is well understood in the printing press art, sheets being printed on a multi-colored printing press are rapidly transferred from the printing station of one color to the printing station for the next color before the inked image printed at one station has had a chance to dry or set to a non-smearing condition, and such transfer is conventionally accomplished by means of a rotating cylinder having conventional sheet grippers thereon for gripping the leading edge of the sheet, with the remainder of the sheet being supported or carried in one way or another by the remainder of the transfer cylinder until the the sheet is delivered to the subsequent printing station. Conventionally, also, it is the newly inked surface of the sheet which contacts or engages the transfer mechanism, so that there is the danger that such contact will smear the wet ink on the newly printed image.

If it is attempted to minimize this difficulty with, for example, bands or strips of rubber or other material located on the transfer cylinder surface, ready adjustment and positioning thereof may be difificult and time consuming. Similarly, if it is attempted to position such bands around the transfer cylinder but axially spaced so as to contact the printed sheet only in negative or noninked areas of the printing thereon, the particular configuration of the image being printed may make this impossible so that, if the rubber or other material is wide enough to aiford the desired or necessary support or gripping pressure, some smearing may occur in Whatever areas of the inked images are actually contacted by the rubber strips. If, on the other hand, it is attempted to minimize surface contact while also providing sufficient support for the sheet by utilizing a plurality of thin discs or plates along the transfer cylinder with serrated or toothed outer edges, smearing of the ink may be adequately minimized but at the risk of imparting to the printed sheet a series of dents or perforations which not only mar the finished appearance but also may interject a further difficulty in stacking and registering the sheets upon completion of the printing operation.

According to this invention, by contrast, there is provided a transfer cylinder of relatively light and simple construction with a working surface of sheet metal around which surface and axially spaced therealong are a plurality of wire or wire spring spacers for preventing contact of the printed surface of the sheet directly with the surface of the transfer mechanism, and with the circular cross section of the spacers providing for only thin line contact with the sheet of such non-smearing nature that "ice a sufficient plurality of spaces can be provided axially along the transfer cylinder to give the desired transfer support to the sheet; and, as a further feature of this invention, means are provided for rapid and easy adjustment of the axial positioning of the spacers, which adjustment is readily accessible to the operator so that the spacers can be rapidly and easily positionedwith regard to the positioning of the inked area of the particular image being printed; and further provision is made for the non-smearing support of the sheet even in situations where optimum positioning of the spacers in accordance with the configuration of the image being printed might permit sagging of the printed sheet into ink-smearing contact with the surface of the cylinder.

With the above objects in View, the invention will now be more particularly described, and other objects and advantages of this invention will be apparent from the following description, the accompanying drawings, and the appended claims.

In the drawing:

FIG. 1 is an end view of transfer cylinder mechanism embodying and for practicing this invention;

FIG. 2 is a partial top view of the mechanism shown in FIG. 1;

FIG. 3 is a somewhat diagrammatic view of a printed sheet with an inked image thereon; and

FIG. 4 is a somewhat diagrammatic view indicating additional means for supporting printed sheet of FIG. 3 on transfer cylinder mechanism embodying and for practicing this invention.

Referring to the drawings, in which like reference characters refer to like parts throughout the several views thereof, transfer cylinder mechanism in accordance herewith is indicated as having a shaft 10 along which are affixed rings 11 with which a plurality of supporting discs 12 are mounted along shaft 10. Over the outer circumferential edges of supporting discs 12 is fastened a sheet metal cover 14 forming the continuous working surface of the cylinder. Within the area not covered by cover 14 (indicated at the top of FIG. 1) are mounted, in known manner, conventional sheet grippers 26, as by gripper supports 21 mounted on shaft 10 at opposite ends thereof for carrying therebetween gripper shaft 22, on which are mounted the plurality of grippers 29 in known manner, so that the grippers 20 may be opened and closed to grip a printed sheet, as under the operation of a lever 23 operated by a cam (not shown), in association with a gripper bar 24, all in known manner.

On each of the two outer supporting discs 12 at opposite ends of cylinder are mounted plates 2% and 26, between each pair of which are mounted U-shaped channels 27 extending longitudinally through the cylinder for slidably receiving therein nipples St? on the ends of wire or spring spacers 31, a plurality of which are spaced along the length of the cylinder and run around the outside surface of cover 14. By virtue of being held in place by nipples 3t interlocked but slidably adjustable in channels 27, the exact axial positioning and adjustment of spacers 31 is readily and rapidly obtained, with the spacers 31 maintaining the axial position in which each is set by virtue of being formed of a helical spring having some inherent tension in a circumferential direction, and also with each of the spacers 31 having a circular cross section as indicated in FIG. 2 for providing minimal contact with a printed sheet carried thereon.

Also mounted or supported on

plates

25 and 26 are longitudinally extending

rotatable shafts

35 and 36 forming spindles or platens around which may be wound opposite axially extending edges of a paper or other cloth or fabric covering or padding for overlying the outer surface of sheet metal cover 14 of the transfer cylinder for the purposes and circumstances described below. At least one end of shafts or

spindles

35 and 36 is provided with some means for maintaining each shaft in a desired angular position, such means being illustrated in the drawings here as comprising

ratchet wheels

39 and 40 with which

pawls

41 and 42 engage, respectively, under the action of

springs

43 and 44. Thus, with the provision of a key-receiving portion (not shown) at the ends of

shafts

35 and 36, rotation of these shafts may be achieved (in opposite directions of rotation) for winding engagement with opposite edges of a fabric or paper covering over the outside of cover 14 (and, as will be understood, beneath the plurality of spacers 31) for tightening such cover over the surface of the cylinder, with

pawls

41 and 42 maintaining

shafts

35 and 36 in a desired angular position. Manual retraction of

springs

43 and 44 and

pawls

41 and 42, then, will permit loosening or unwinding

shafts

35 and 36 for removal of any paper or fabric padding or covering wound thereon.

As noted above, it is optimumly desired to space the various wire spring spacers 31 axially along the cylinder so that, if possible, they contact the printed sheet only in negative or non-inked areas of the printed image thereon. When the printed image on the sheet includes matter arranged in columns, for example, this objective might readily be accomplished merely by moving the spacers along the cylinder without even having to loosen or/ tighten a set screw or other arrangement to aid mate rially in the ease and economy of time necessary for the adjustment.

In many cases, however, the configuration of the inked image on the printed sheet may not be so conveniently arranged, in which case the spacers 31 are positioned axially on the cylinder so as to contact inked areas as little as possible. In such a case, the design of the inked image may be such as to suggest spacing the wire springs 31 axially so far from each other that the paper sheet may sag in areas between spacers 31 sufficiently to touch the surface of cover 14 of the cylinder. As illustrative of such a situation, the diagram of FIG. 3 is noted as indicating a printed sheet 50 on which there is an inked image indicated by the cross-hatched areas 51. If it were decided that the spacers 31 on the transfer cylinder to handle this particular printed sheet should be axially positioned so as to contact the sheet only along the dot-dash lines 31', there might be a tendency for the sheet 50 to sag against the surface 14 of the cylinder in the central area between the lines 31, and particularly might this occur when the printed sheet comprises particularly smooth or thin paper.

In such a situation, it may be desired to cover the entire working surface 14 of the cylinder with an ink-repellent or smear-resisting cover or blanket so that smearing of the inked image is avoided or minimized even if the sheet should sag between spacers 31 sufficiently to come into actual contact with the surface 14 of the cylinder. Such a covering is readily applied, as aforesaid, by being wound on or held between the spindles or

platens

35, 36. One such ink-resistant covering or blanket with which satisfactory results have been achieved in accordance herewith comprises a paper or fabric base having thereon a coating of rubber or like material in which are embedded tiny spherical glass beads. Because of the nature of these glass beads, they do not readily pick up ink from the inked image on the sheet and, because of their size and spheric shape, there is virtually only point contact with the ink. One satisfactory, commercially available form of such a covering fabric is sold by Minnesota Mining and Manufacturing Co., St. Paul, Minnesota, under the designation Spherekote blankets.

In a situation as depicted in FIG. 3, however, an additional amount of non-smearing support for the surface of the printed sheet may be desired to engage the sheet over a greater extent of its total surface area and/ or to prevent, for other reasons than smearing, sagging of central portions of the printed sheet between spaces 31. In such a situation, a negative template of the entire inked image 51 may be cut out of felt or cardboard or other padding and placed around the surface 14 of the cylinder to be held in place by winding opposite axial edges of the template on

spindles

35 and 36, or individual strips forming such negative template may be directly affixed, as by an adhesive, to the surface 14 ofthe cylinder, as indicated in FIG. 4 by the strips 52, so that a substantial area of contact of the printed sheet 50 is provided, but only in non-inked portions of the image thereon.

As will be apparent from the foregoing, then, this invention provides a transfer cylinder of the character described having readily adjustable spacing means axially along the surface thereof to engage the printed surface of the sheet at a desired plurality of positions, each of which is readily and quickly selected with respect to noninked areas of that particular printed image. Additionally, there is also disclosed in connection herewith additional expedients for providing a desired support and avoidance of smearing or marring the printed image even in situations where the configuration of the image is such as to preclude the adjustment of circumferential spacers to contact the sheet only in non-inked areas thereof; and all without altering the mechanical construction of the transfer cylinder from one job to another and yet without contacting the sheet with perforating or other marring transfer elements.

While the forms of apparatus herein described constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What I claim is:

1. In a transfer cylinder for a multi-color rotary printing press for transferring a printed sheet of paper from a printing station without marring the printed surface of said sheet, the combination which comprises a substantially smooth working surface on said cylinder and extending around a major portion of the circumferences thereof, sheet gripping means on said cylinder for engaging a leading edge of said sheet and drawing it around said cylinder with said printed surface of said sheet facing said working surface of said cylinder, and a plurality of helical wire springs extending circumferentially around said cylinder forming discontinuous but relatively smooth spacing means for separating said printed surface of said sheet from contact with said working surface of said cylinder, said springs being spaced apart axially along said cylinder for contacting said printed surface of said sheet only in selected areas thereof and without embossing or marking said sheets.

2. A transfer cylinder as recited in claim 1 in which said smooth working surface of said cylinder comprises a thin metal shell.

3. A transfer cylinder as recited in claim 1 for use where said printed sheet has a discontinuous printed image thereon having inked and non-inked areas, and on which cylinder said helical springs are adjustable to contact said printed sheet in only said non-inked areas thereof said helical springs having the ends thereof connected to slidable fastenings in the surface of said cylinder for adjustment of said helical springs axially along said smooth working surface of said cylinder.

4. A transfer cylinder as recited in claim 1 in which portions of said working surface of said cylinder between said separate spacing means thereon are covered with an ink repellent covering for avoiding marring of any portion of said printed surface of said sheet which contacts said covering.

5. In a transfer cylinder for a multi-color rotary printing press for transferring a printed sheet of paper from a printing station without marring the printed surface of said sheet, the combination which comprises a thin metal shell as a substantially smooth working surface on said cylinder and extending around a major portion of the circumference thereof and substantially continuously axially therealong, opposite axial edges of said shell defining therebetween an open slot axially of said cylinder, sheet gripping means in said slot for engaging a leading edge of said sheet and drawing it around said cylinder with said printed surface of said sheet facing said working surface of said cylinder, and a plurality of helically wound wire springs extending circumferentially around said cylinder and adjustably slidable thereover for separating therefrom said printed surface of said sheet, and means in said slot for engaging opposite ends of said helical springs forming substantially the sole fastening of said springs to said cylinder, said springs being relatively smooth and positioned on said working surface for contacting said printed surface of said sheet only along discontinuous lines and in the absence of embossing or making thereof.

6. A transfer cylinder as recited in claim 5 in which said means for engaging opposite ends of said springs comprises axial guide channels in said slot in said cylinder and means on said opposite ends of said springs for axially slidable engagement in said channels.

7. A transfer cylinder as recited in claim 5 in which means are provided in said slot and adjacent each opposite axial edge thereof for engaging opposite axial edges of an ink repellent covering sheet for said working surface of said cylinder to maintain said covering over said working surface.

8. A transfer cylinder as recited in claim 7 having 6 accessible at the ends thereof means for operating said means for engaging said sheet covering.

9. In a transfer cylinder for a multi-color rotary printing press for transferring a printed sheet of paper from a printing station without marring the printed surface of said sheet, the combination which comprises a thin cylindrical shell having a smooth working surface on said cylinder and extending around the surface thereof, sheet gripping means on said cylinder for engaging a leading edge of said sheet and drawing it around said shell with said printed surface of said sheet facing said working surface of said shell, and spacing means on said working surface of said shell comprising substantially smooth and flat cut out pieces conforming to nonprinted areas of said sheet and aflixed to and positioned on said working surface of said shell for contacting said printed surface of said sheet only on selected nonprinted areas thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,106,067 Wood Aug. 4, 1914 1,223,023 Barber Apr. 17, 1917 1,872,421 Doyle Aug. 16, 1932 2,740,355 Wimpfheimer Apr. 3, 1956 FOREIGN PATENTS 355,372 Great Britain Dec. 14, 1925