Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/01—Means for holding or positioning work
  • B26D7/02—Means for holding or positioning work with clamping means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/18—Means for removing cut-out material or waste
  • B26D7/1845—Means for removing cut-out material or waste by non mechanical means
  • B26D7/1863—Means for removing cut-out material or waste by non mechanical means by suction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
  • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
  • B26F1/38—Cutting-out; Stamping-out
  • B26F1/384—Cutting-out; Stamping-out using rotating drums
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41G—APPARATUS FOR BRONZE PRINTING, LINE PRINTING, OR FOR BORDERING OR EDGING SHEETS OR LIKE ARTICLES; AUXILIARY FOR PERFORATING IN CONJUNCTION WITH PRINTING
  • B41G7/00—Auxiliary perforating apparatus associated with printing devices

Definitions

• the invention relates to a method for inline punching in sheetfed offset printing according to the preamble of claims 1, 8 and 10.
• the invention further relates to a sheetfed offset press suitable for inline punching according to the preamble of claims 12, 19 and 20 and a punching plate for clamping a cylinder of a printing unit or coating unit of a sheet-fed offset printing press according to the preamble of claim 21.
• a method of the type mentioned is already known in which sheets printed in a sheet-fed offset printing press in the last printing unit of the printing press pass through the gap between the blanket cylinder provided with a clamped sheet metal and the impression cylinder provided with a protector plate are punched out.
• the known printing machine has a suction device with a suction funnel, which is connected to an un can be acted upon and has a suction opening facing the impression cylinder for the punching waste.
• the negative pressure applied to the suction funnel not only causes the punching waste to be suctioned off, but also exerts a suction effect on the sheets transported under the suction opening. Since the sheets are only held at their front edge by gripper systems of the impression cylinder and otherwise lie loosely on its outer surface or the outer surface of the protector plate, the suction effect can cause the sheets to lift off.
• stamping arrangement with a suction device for a sheet-fed offset printing press in which the punching arrangement arranged behind the last printing unit of the printing press comprises two cylinders and is used for punching out printed sheets in a gap between the two cylinders, one of which transports the sheets on its circumference and the other other is provided with clamped sheet metal on its circumference.
• the suction device there has two suction funnels arranged side by side in the axial direction of the cylinders, next to each of which several blow air nozzles are arranged. Compressed air is blown onto the sheets from the blown air nozzles in order to press them against the lateral surface of the transport cylinder and thereby avoid destabilization or fluttering of the sheets as a result of the negative pressure in the suction funnel.
• the arrangement has the disadvantage that a relatively large effort is required to convert the printing press if the size, number and / or position of the cutouts to be punched out in the sheet in the axial direction of the cylinders changes.
• the object of the invention is to improve a method and a sheet-fed offset printing press of the type mentioned at the outset in such a way that the sheets are prevented from being lifted off from the impression cylinder using simpler means.
• the punched sheet is provided with protruding pressure strips in order to press the sheets against the impression cylinder in the area of the gap and thus to shift the sheets with respect to one another to the surface of the impression cylinder as a result of the negative pressure exerted on the sheets during suction.
• the invention is based on the idea of preventing the sheets from lifting off the surface of the impression cylinder or a protector plate mounted thereon, in that the sheet during its passage under the suction opening of the suction device not only at its front edge from the gripper systems against the surface of the impression cylinder is held tight, but additionally also in the gap arranged behind the suction opening in the direction of movement, so that both register differences and contact with the edge of the suction opening are reliably prevented.
• the pressure strips are preferably arranged on the stamping plate in such a way that they over unprinted surfaces or in
• the suction is interrupted according to a further preferred embodiment of the invention until the rear edge of the sheet has moved at least partially and preferably entirely under the suction opening of the suction device.
• the print image is expediently arranged on the sheet so that its rear edge is free of punched-out cutouts.
• adjustable hold-down devices or rollers can be arranged in the area of the suction opening of the " suction device, which suction the rear Prevent the edge of the arch
• the suction is preferably in synchronization with the rotation of the impression cylinder or
• Blanket cylinder interrupted, expediently by an interrupter element rotatable synchronously with the counter-pressure cylinder, which keeps an opening in a suction channel of the suction device closed whenever the rear edge of an arc leaves the gap and moves under the suction opening of the suction device.
• the suction opening of the suction device extends over the entire width of the sheet, so that when changing the size, number or position of the cutouts on the sheet, no retrofitting measures are required other than clamping a new punching sheet are.
• Suction opening are entrained in, sees a further preferred embodiment of the invention and at the same time independent variant of the invention, based on the patent, proposes that the counter-pressure cylinder or the protector plate attached thereon has elastically deformable pads on its outer surface below the cutouts to be punched out. These pads are compressed as they pass through the gap and, after exiting the gap, due to their expansion exert a force directed away from the surface of the impression cylinder on the waste pieces punched out of the cutouts, so that these are pressed out of the cutouts and into the suction opening be sucked.
• the cushions are preferably somewhat smaller than the cutouts and are expediently glued onto the impression cylinder or the protector plate below the cutouts of the sheet as required.
• the stamping plate is preferred according to yet another
• a suitable liquid is, for example, silicone oil, which is already used in offset printing for similar purposes and is expediently applied here in the form of a fine spray mist to the outer surface of the punching sheet every time the blanket cylinder rotates.
• Spraying the stamping sheet with a liquid that prevents ink from adhering also basically allows the pressure strips to be arranged, if necessary, instead of over unprinted areas or intermediate cut areas over the printed areas of the sheet, since the liquid prevents the ink from adhering to the top of the pressure strips ,
• the invention is described in more detail below with reference to an exemplary embodiment shown in the drawing. Show it:
• Fig. 1 a schematic partially sectioned side view of a sheet-fed offset printing machine
• FIG. 2 shows a schematic, partially sectioned side view of an enlarged section of the last printing unit of the sheet-fed offset printing press from FIG. 1;
• FIG. 4 a perspective view of a part of the stamping plate from FIG. 3;
• Fig. 5 is a sectional view of the punch plate along the line V-V of Fig. 4;
• FIG. 7 a view corresponding to FIG. 6, but with a modified impression cylinder
• sheets 1 made of a printing material, in particular paper are successively by means of an automated sheet feed 4 from a sheet stack 8 arranged in a sheet feeder 6 of the printing press 2 to a feed drum 10 of a first printing unit 12, then printed in this and other printing units (not shown) on one or both sides in one or more colors, before in the last printing unit (or alternatively in a downstream coating unit) 14
• Printing machine 2 cutouts 3 are punched out of the sheet 1.
• the printing or coating unit 14 of the printing press 2 used for punching out the sheets 1 has a structure corresponding to that of the other printing units 12, so that it can be used either for printing or coating or for punching.
• the printing or coating unit 14 essentially comprises an inking unit 16 and a dampening unit 18 and a, respectively
• Coating unit a plate cylinder 20, a blanket or lacquer cylinder 22, and an impression cylinder 24, from which the printed and die-cut sheets 1 are transferred via a delivery drum 26 to a chain delivery 28 of a sheet delivery 30 of the printing press 2 and from there for storage on a sheet stack 32 can be transported through the display 30.
• the cutouts 3 are punched out of the sheets 1 in a gap
• the printing unit 14 has a suction device 40 with which the
• Stamped wastes 38 are suctioned off immediately after they emerge from the gap 34.
• the punching plate 36 in the embodiment shown in the drawing is provided with three rows of punching tools 42 which run circumferentially around the cylinder 22 and are arranged next to one another in the axial direction thereof, with which the cutouts 3 in FIG Gap 34 between the cylinder 22 and the impression cylinder 24 are punched out of printed areas of the sheet 1.
• the punched-out sections 3 have a rectangular shape there and are arranged at a distance from the edges of the sheet 1, but any other shape can be punched out at any point on the sheet.
• each of the punching tools 42 consists of a punching ridge 44 which protrudes along the outline of the section 3 to be punched out over the outer surface 46 of the punching plate 36 facing away from the cylinder 22.
• the punching burr 44 which is machined out of the material of the punching sheet 36 by etching and subsequent mechanical processing of its surface, has a cross-sectional shape which is customary for punching burrs, with two oblique flanks 48 which taper to a sharp cutting edge 50 on its upper edge.
• the height of the punch burrs 44 in relation to the surface 46 of the punch plate 36 depends on the thickness of the sheet 1 to be punched out. When punching sheet 1 from paper with a customary basis weight of 80 g / m 2 and a thickness of about 80 ⁇ m, the height is
• the suction device 40 essentially consists of a suction funnel 56 arranged inside the printing unit 14 with a suction opening 58 facing the impression cylinder 24, and one from the top end of the suction funnel 56 from the printing press 2 to the outside leading and communicating there with a vacuum source (not shown) suction channel 60, and a device 62 arranged outside the printing machine 2 along the suction channel 60 for intermittent interruption of the suction during the rotation of the impression cylinder 24.
• the suction funnel 56 is height-adjustable in the radial direction of the counter-pressure cylinder 24, so that the suction opening 58 can be positioned at a radial distance of 10 to 50 mm above the outer surface 54 of the protector plate 56, depending on the material thickness and rigidity of the sheet 1 to detect the punching waste 38 separated from the sheet 1 in the gap 34 along its outer edge immediately after it emerges from the gap 34 by the negative pressure generated by the negative pressure source and to suck it into the suction opening 58 of the suction funnel 56, as schematically shown by the arrow U in FIG 6 and 7 are shown.
• the pads 64 are made Expediently made of an elastomer material which can be reversibly deformed under pressure, such as foamed polyurethane or foam, and in the undeformed state have a thickness of 0.5 to 5 mm. Their dimensions in the circumferential direction or in the longitudinal direction of the impression cylinder 24 are preferably somewhat smaller than those of the cutouts 3, as shown in FIG. 7.
• an air curtain 55 is provided in the direction of rotation of the counter-pressure cylinder 24 behind the suction funnel 56 of the suction device 40 and preferably extends over the entire width of the counter-pressure cylinder 24.
• air curtain 55 air is blown behind the suction funnel 56 from a nozzle bar 57 radially, or preferably at an acute angle, against the peripheral surface 54 of the counter-pressure cylinder 24.
• the air curtain 55 ensures that the punching waste 38 whirls up in the rear part of the suction opening 58 facing away from the gap 34 and thus detaches itself from the pads 64 at the latest, thereby preventing individual punching waste 38 from passing under a rear edge of the suction opening 58.
• Sheet grippers 66 (Fig. 1) held and otherwise loosely lying on the surface 54 of the protector plate 52 sheet 1 are sucked due to the vacuum generated by the suction device 40 to the suction opening 58 of the suction funnel 56, the punching plate 36 is in the axial direction between adjacent rows of Punching tools 42 and on each of their side edges are provided with a protruding pressure bar 68, which presses the sheet 1 in the gap 34 against the surface 54 of the protector plate 52.
• the sheets 1 are prevented from shifting in relation to the protector sheet, which leads to register differences when punching would.
• a plurality of rollers 59 are also arranged side by side within the suction funnel 56 in the axial direction of the cylinders 22, 24, which roll on the sheet 1 moving under the suction opening 58 and these at a distance from the front and rear edge of the suction opening 58 hold.
• the rollers 59 are resiliently mounted so that they are elastically flexible under the rollers 59 when the sheet grippers 66 of the impression cylinder 24 pass through.
• the rollers 59 can be moved in the axial direction along their axis of rotation, so that they can be adjusted before punching in such a way that they rest on the unprinted areas of the sheets 1, i.e. roll along the sheet edges and / or along the gaps between adjacent printed areas of sheets 1.
• the pressure strips 68 running in the circumferential direction of the blanket cylinder 22 are lower than the stamping ridges 44 and have a flattened top side 70 with a width of a few
• the height of the pressure strips 68 above the surface of the stamping plate 36 is preferably selected such that the pressure strips 68 do not leave any permanent deformation in the surface of the printing material emerging from the gap 34. In the case of a sheet of paper with a customary basis weight of 80 g / m and a thickness of approximately 80 ⁇ m, this is achieved if the pressure strips 68 at the narrowest point of the gap 34 do not exceed 30 ⁇ m and preferably do not exceed 20 ⁇ m penetrate the punched sheet 36 facing printed surface of the sheet 1. This means that with such Printing material, the height of the pressure strips 68 must be approximately 100 ⁇ m lower than the height of the cutting edges 50 of the stamping burrs 44 and is thus between approximately 20 and 40 ⁇ m starting from the surface 46.
• the pressure strips 68 are etched out of the punched sheet 36 and reworked mechanically.
• the arrangement of the pressure strips 68 on the punching plate 36 and the arrangement of the printed images on the sheet 1 are selected such that the pressure strips 68 are in the unprinted ones Areas of sheet 1, ie run along the sheet edges and / or along the gaps between adjacent printed areas of sheets 1.
• the stamping plate 36 preferably has between two and eight pressure strips 68 across the width of the blanket cylinder 22, but their number can also be greater. As long as it is ensured that the sheet 1 is held there as it passes through the gap 34, not all pressure strips 68 need to run over the entire punched sheet 36, but can also have interruptions.
• the lower end of the suction funnel 56 which extends over the entire width of the counter-pressure cylinder 24, can be partially closed by thin sheets (not shown), so that only above of
• the suction funnel 56 has a curvature which is adapted to the curvature of the protector plate 54 and is fastened in the region of the suction opening 58 in such a way that it extends in the circumferential direction of the counter-pressure cylinder 24 beyond the opening 58.
• the spaces between these sheets are slightly larger than the width of the cutouts 3, which are expediently arranged in one or more aligned rows in the circumferential direction of the blanket cylinder 22, as in FIG. 3 shown.
• the suction of the punching waste 38 is interrupted synchronously with the rotation of the impression cylinder 24 as soon as the rear edge of each sheet 1 passes through the gap 34 the blanket cylinder 22 and the impression cylinder 24 moved through.
• the device 62 which is arranged outside the printing press 2 in the suction channel 60, is provided which enables an intermittent interruption of the suction air flow. As best shown in FIGS.
• the device 62 essentially consists of an interrupter element 74 which is fastened within a cylindrical section 76 of the suction channel, which section is closed at the rear end, on a shaft 78 which is rotatably mounted about the longitudinal axis of section 76.
• the interrupter element 74 has two diametrically opposed cylinder segments 80 with closed outer circumferential surfaces for mass compensation, which move along the inner wall of the suction channel 60 at a small distance and close a lateral air outlet 82 of the suction channel 60 twice with each full rotation of the interrupter element 74.
• the shaft 78 is connected via a gear (not shown) to an output shaft of the printing press 2 and is synchronized with it by the rotation of the impression cylinder 24 driven so that the circumferential surfaces of the cylinder segments 80 close the air outlet 82 whenever the rear edge of a sheet 1 carried by the impression cylinder 24 emerges from the gap 34 and keep the air outlet 82 closed essentially as long as the sheet 1 is underneath of the suction opening 58.
• the interrupter element 74 can also be formed by a hollow cylinder, the wall of which is provided with a pair of diametrically opposed axial slot openings, one of which overlaps with the inlet opening of the side air outlet 82, as long as the rear edge of the sheet is still in the gap 34 is located.
• the air outlet 82 is then closed by a jacket section of the cylinder arranged between the slot openings until the rear edge of the sheet 1 has essentially moved under the suction opening 58 of the suction funnel 56.
• a spray device 86 is further provided, which makes it possible to cover the surface 46 of the punching sheet 36 with silicone oil or another, to spray ink adhering liquid.
• the spray device 86 can comprise a series of flat jet nozzles 88, which are preferably arranged next to one another in the direction of movement of the cylinder 22 in front of the gap 34 at a radial distance from the surface 46 of the punch plate 36 such that their spray jets at least spray the dies 42 with a fine spray of the liquid.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Inking, Control Or Cleaning Of Printing Machines (AREA)
• Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Manufacture Of Motors, Generators (AREA)
• Screen Printers (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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Family Cites Families (8)

• 2003
  • 2003-08-21 DE DE10338352A patent/DE10338352A1/de not_active Withdrawn
• 2004
  • 2004-08-18 AT AT04764238T patent/ATE385897T1/de not_active IP Right Cessation
  • 2004-08-18 WO PCT/EP2004/009252 patent/WO2005021265A2/fr not_active Ceased
  • 2004-08-18 DK DK04764238T patent/DK1656259T3/da active
  • 2004-08-18 EP EP04764238A patent/EP1656259B1/fr not_active Expired - Lifetime
  • 2004-08-18 DE DE502004006202T patent/DE502004006202D1/de not_active Expired - Lifetime

Non-Patent Citations (1)

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