Sheet-fed printing press

Abstract

Sheet-fed printing press, with a feeder (11) for feeding sheets to be printed into the sheet-fed printing press, with at least one printing unit (12; 23) and / or coating unit (13; 24) for printing the sheets with a static print image identical for all sheets, with a delivery unit (14) for ejecting printed sheets from the sheet-fed printing press, and with at least one printing formless printing device (17, 18; 29) integrated into the sheet-fed printing press for printing the sheets with a variable print image, wherein the or each printing formless printing device (17, 18; 29) is integrated into the sheet-fed printing machine in the area of ​​the feeder (11), and wherein the or each printing formless printing device (17, 18; 29) prints the printing sheets from above in the area of ​​the feeder (11), characterized by that the investor (11) is trained as a single-sheet investor, that the or each printing formless printing device (18) is integrated into the sheet-fed printing machine (10) above a feed table (19) of the single-sheet feeder, in the area of ​​which the printed sheets are guided on an underside of the same by at least one suction belt, wherein a sensor system is provided for detecting the front edge and side edge of each printed sheet, and that the variable print image is applied inline to the printing of the sheets with the static print image, whereby the variable print image is applied before the printing of the sheets, wherein at least one characteristic curve is stored in a control device of the printing formless printing device (17, 18; 29) which depends on substrate characteristics such as the grammage and / or the fiber direction and / or the stiffness of the printing sheets, wherein the printing formless printing device (17, 18; 29) can be controlled on the basis of these characteristic curves when the transport speed of the printed sheets changes during the feeding of the printed sheets into the sheet-fed printing machine via the pre-grabber (21).

Description

[0001] The invention relates to a sheet-fed printing press according to the preamble of claim 1.

[0002] Sheet-fed offset printing presses increasingly utilize formless printing units, primarily for customizing offset-printed products with barcodes, numbering, or other markings. These formless printing units are also known as non-impact printing (NIP) units and can be inkjet printers equipped with at least one inkjet printhead. Each printhead can operate on a continuous inkjet, drop-on-demand, thermal, or other inkjet principle. Formless or NIP printing units can also be laser printers.

[0003] From DE 197 04 003 A1, a sheet-fed printing press is known in which a formless printing unit, designed as an inkjet or laser printing unit, is integrated into an offset printing unit of the sheet-fed printing press. The formless printing unit is located opposite a sheet-guiding impression cylinder in the area after the sheets have passed through a printing gap formed by the impression cylinder and a rubber cylinder. With this printing press, printing on sheets with high stiffness in the area of ​​the inkjet or laser printing unit is particularly problematic.

[0004] This is because such printed sheets tend to spring upwards in the area of ​​the sheet's trailing edge after leaving the printing gap, and thus the distance between the printing unit without a printing form and the printed sheet can change abruptly, which is why the printed sheets can hit the printing unit without a printing form without appropriate guide elements and therefore the printed sheets in the area of ​​the sheet's trailing edge cannot be printed with the same quality as in the area of ​​a sheet's leading edge and / or the sheet's center.

[0005] To fix the printed sheets to the surface of the impression cylinder, DE 197 04 003 A1 proposes sheet guide rollers. However, these rollers cover portions of the printed sheets, which means that the printing sheets in the printing press according to DE 197 04 003 A1 cannot be printed across the entire format width by the formless printing unit. Furthermore, the arrangement of the formless printing unit in the area of ​​the printing gap implies that the formless printing unit will make indentations in freshly printed sheets. This creates the risk that the sheet guide rollers will leave marks on the surface of the printed sheets, thus impairing the achievable print quality.

[0006] Another sheet-fed printing machine with an integrated, formless printing unit is known from DE 195 14 259 A1, wherein, according to this prior art, the formless printing unit is integrated into the sheet-fed printing machine behind the last offset printing unit and in front of a delivery arm in the transport direction of the sheets.

[0007] A sheet-fed printing press is known from EP 0 769 376 A1. The printing cylinder, which forms the printing gap with the image-printing cylinder, interacts with two transfer cylinders that feed and remove the sheets. The transfer cylinder has a substantially closed cylindrical circumferential surface into which a suction bar is embedded at the beginning of each printing segment to draw in the leading edge of a sheet. The two transfer cylinders are also equipped with suction bars that are aligned with the suction bars of the printing cylinder and additionally have plungers that lie in gaps in the plungers. The sheet transfer to and from the printing cylinder is effected by alternately switching the suction air on and off at the respective suction bars.When passing through the pressure gap, the immersion grippers of the transfer cylinders assume their submerged position, while outside the pressure gap they assume their raised position to hold the sheets during the shutdown of the suction air of the respective suction bar.

[0008] From DE 100 46 466 A1, a modular printing press system for printing sheets is known. It consists of a first printing press designed in a satellite configuration with a central first impression cylinder and at least four printing units associated with it, a second printing press with a second impression cylinder, and a coupling device for connecting the printing presses to each other for inline operation. The printing press system is characterized by the fact that at least one adjusting device for register correction is assigned to each of the feeding devices used for transferring the sheets to the second impression cylinder – in particular, a feeding drum.

[0009] German patent DE 10 2005 021 185 A1 discloses a method and device for applying opaque white and effect layers to a substrate. The application is carried out using one or more inkjet printheads. The opaque white or effect layer can be applied directly to the substrate or indirectly via a printing plate. Possible installation locations for such an inkjet device are above a roller conveyor of a roll-to-sheet feeder or above the feeder of a sheetfed offset printing press. A characteristic feature of the opaque white or effect layers is that they are dried or cured after application and then at least partially printed using offset printing.

[0010] Starting from this premise, the present invention addresses the problem of creating a novel sheet-fed printing machine.

[0011] This problem is solved by a sheet-fed printing machine according to claim 1.

[0012] According to the invention, the or each printing formless printing device is integrated into the sheet-fed printing machine in the area of ​​a feeder, wherein the feeder is configured as a single-sheet feeder.

[0013] In accordance with the present invention, it is proposed to integrate the or each printing formless printing device into the feeder area of ​​the sheet-fed printing press. Accordingly, in accordance with the present invention, the printing of sheets using the or each printing formless printing device takes place at a point in time prior to the printing of the sheets in the printing units of the sheet-fed printing press, which are preferably designed as offset printing units. Since the sheets to be printed are flat in the feeder area and not curved as in the printing units of the sheet-fed printing press, the printing process is not necessarily limited by the fact that the printing process is not limited by the fact that the printing units of the sheet-fed printing press are not curved.If the printing plates are aligned, the printing devices without printing plates can be arranged at a small distance from the printing sheets without the need for sheet guide rollers rolling on the side of the printing sheets to be printed, which on the one hand impair the print quality and on the other hand limit the width of the printing sheets that can be printed in the area of ​​the or each printing plate without printing plate.

[0014] Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1: a sheet-fed printing press according to a first embodiment of the invention; Fig. 2: a sheet-fed printing press according to a second embodiment of the invention; and Fig. 3: a section of a sheet-fed printing press according to a third embodiment of the invention.

[0015] The invention presented here will now be described with reference to Fig. 1, Fig. 2 to Fig. 3 described in greater detail.

[0016] Fig. Figure 1 shows a schematic representation of a sheet-fed printing press 10 according to the invention, wherein the sheet-fed printing press 10 comprises a feeder 11, several printing units 12 designed as offset printing units, a coating unit 13 downstream of the printing units 12, and a delivery unit 14 downstream of the coating unit 13. The feeder 11 serves to introduce sheets to be printed into the sheet-fed printing press 10, wherein the sheets are moved through the printing units 12 and the coating unit 13 and printed with a static image that is the same for all sheets. In the area of ​​the delivery unit 14, printed sheets are ejected from the sheet-fed printing press, forming a delivery stack 15. In the illustrated embodiment of the Fig. 1 The sheet-fed printing press 10 according to the invention is designed as a so-called perfecting press, which serves for printing on both sides of printed sheets in so-called perfecting. A transfer cylinder arranged between the two first printing units 12 is designed for this purpose as a perfecting cylinder 16.

[0017] The sheet-fed printing press 10 according to the invention incorporates at least one printing unit without a printing plate, which preferably serves to print the sheets with a dynamic or variable print image. According to the present invention, the printing unit or units without a printing plate are integrated into the sheet-fed printing press 10 in the area of ​​the feeder 11, wherein in Fig. One possible installation position, 17 and 18, for the or each formless printing device is shown schematically. In both installation positions 17 and 18, the printing sheets are printed from above in the area of ​​the feeder 11 via the or each formless printing device.

[0018] In the case where the feeder 11 is designed as a so-called single-sheet feeder, the preferred installation position 18 for each printing unit without a printing plate is above a feed table 19, over which printed sheets lifted from a feeder stack 20 are fed to the first printing unit 12 of the printing press. In the area of ​​the feed table 19, the printed sheets are guided on their underside by at least one suction belt, so that the printed sheets can be printed on one side by the printing unit(s) without a printing plate, namely across their entire width and length. During transport of the printed sheets along the feed table 19, the printed sheets are aligned flat. A small distance can be maintained between the printing unit(s) without a printing plate and the printed sheet, thus ensuring high print quality.

[0019] If a printing formless printing unit is integrated into a single-sheet feeder 11 in installation position 18 above a feed table 19, the installation position along the feed table 19 is freely selectable. To control the printing formless printing unit, at least one leading edge and one side edge of the printed sheets must be detected and evaluated in order to print the sheets in the desired zones. The sensors required for detecting the leading and side edges can be infrared, ultrasonic, or capacitive sensors.

[0020] In the case where the feeder 11 is designed as a so-called shingle feeder, the installation position 17 is preferred for the or any printing formless printing device, namely above a in Fig. 1. The feeder plate (not shown) of the shingle feeder, in the area of ​​the feeder plate, separates the printed sheets and grips them by a so-called pre-gripper 21 and feeds them to the first printing unit 12 of the sheet-fed printing press 10. In this case, too, the printed sheets can be printed with a dynamic or variable print image by the or any printing formless printing unit across the entire format width and length.

[0021] If a die-free printing unit is integrated into a feeder 11 designed as a shingle feeder in installation position 17 adjacent to the pre-gripper 21, then at least one leading edge of the printed sheets must be detected and evaluated to control the die-free printing unit and print the sheets in the desired zones. The sensors required for detecting the leading edge can be infrared, ultrasonic, or capacitive sensors. A sheet guide is preferably positioned between the die-free printing unit 17 and the pre-gripper 21, which can be moved into areas or zones of the printed sheets that are not to be printed by the die-free printing unit.

[0022] If the transport speed of the printed sheets changes when they are fed into the sheet-fed printing press via the pre-gripper 21, then preferably at least one characteristic curve is stored in a control unit of the formless printing unit. This curve depends on substrate properties such as the basis weight and / or the fiber direction and / or the stiffness of the printed sheets. The formless printing unit is then controlled based on one of these characteristic curves. The characteristic curves are determined in advance for printed sheets made of different substrates.

[0023] The or each printing formless printing device integrated into the sheet-fed printing machine 10 is preferably designed as an inkjet printing device or laser printing device, wherein such printing devices have several inkjet printheads or laser printheads arranged next to each other when viewed transversely to the transport direction of the printed sheets, and several inkjet printheads or laser printheads arranged one behind the other when viewed in the transport direction of the printed sheets, which are arranged in an array-like or matrix-like manner and are preferably interconnected on the control side.

[0024] The number of printheads required perpendicular to the printing direction is primarily defined by the desired total print width in relation to the given print width of the printhead used.

[0025] The required number of printheads in the transport direction of the printed sheets is determined by the fact that the desired printing speed is greater than the given printing speed of a single printhead, and by the fact that multiple inks are to be applied to the printed sheets using the formless printing unit. Furthermore, the number of printheads in the transport direction is defined by the desired print resolution in relation to the given print resolution of the printhead used.

[0026] As already mentioned above, the printing units 12 and the coating unit 13 of the sheet-fed printing machine 10 according to the invention of the exemplary embodiment of the Fig. 1. The printing of the sheets with a static print image that is identical for all sheets. The printing formless device integrated into the sheet-fed printing press 10 in the feeder area 11, on the other hand, serves to print the sheets with a dynamic or variable print image, whereby the printing with the dynamic or variable print image takes place inline with the printing of the sheets with the static print image, and specifically before the printing of the sheets in the printing units 12 and the coating unit 13.

[0027] The invention is not limited to use in the Fig. The invention is not limited to the configuration of a sheet-fed printing press shown in Figure 1; rather, it can be used in any sheet-fed printing press. For example, Figure 1 shows... Fig. 2 the application of the invention to a sheet-fed printing press 22, in which, viewed in the transport direction of the printed sheet, a printing unit 23 designed as a flexographic printing unit is arranged after the feeder 11 and, viewed in the transport direction of the printed sheet, a coating unit 24 is arranged in front of the delivery 14, and wherein two drying devices 25 are positioned between the flexographic printing unit 23 and the coating unit 24.

[0028] Even in the exemplary embodiment of the Fig. 2. At least one printing formless printing device is integrated into the sheet-fed printing machine 22 in the area of ​​the feeder 11, namely either in the area of ​​installation position 17 or in the area of ​​installation position 18, so that the descriptions of the exemplary embodiment of the Fig. 1 can be referenced. As already mentioned in connection with the exemplary embodiment of the Fig. As mentioned in point 1, installation position 17 is preferred for a feeder designed as a shed feeder and installation position 18 is preferred for a feeder designed as a single-bow feeder.

[0029] Fig. Figure 3 shows a section of another sheet-fed printing press 26 according to the invention, in which the feeder 11 is designed as a roll-to-sheet feeder, and in which, viewed in the transport direction of the printed sheets, two printing units 12 designed as offset printing units are arranged downstream of the roll-to-sheet feeder 11. The roll-to-sheet feeder 11 comprises a sheet-to-roll cutter 27, which is also referred to as an inline sheeter. In the area of ​​the sheet-to-roll cutter 27, printed sheets are cut from a roll-shaped substrate 28, which are then fed via a feed table 19 to the first printing unit 12 of the sheet-fed printing press 26. In the case in which the feeder 11 is designed as a roll-to-sheet feeder, the or each printing unit without a printing form is preferably located on the Fig.The installation position 29 shown schematically in Figure 3 is integrated into the feeder 11 of the sheet-fed printing press 26 according to the invention. In this case, too, the printed sheets can then be printed from above with a variable or changeable print image across the entire format width and length.

[0030] According to an advantageous further development of the present invention, the or each printing formless printing device can be disassembled from the sheet-fed printing machine in such a way that the or each printing formless printing device can be used on another sheet-fed printing machine or within the same sheet-fed printing machine at different installation positions.

[0031] For this purpose, each formless printing device has a supply-side interface, namely mechanical or ink-side, and a control-side interface, namely electrical or electronic, via which each formless printing device can be connected to an ink supply system or to a control unit of the respective printing machine.

[0032] If printing units without printing plates are integrated into a sheet-fed printing press at several installation positions, the electrical and mechanical interfaces for these printing units can be centralized. Supply lines leading to each printing unit without printing plates, whether electrical, mechanical, or ink-related, can either be permanently installed on the sheet-fed printing press according to the invention or routed to the sheet-fed printing press via mobile units. The ability to remove each printing unit without printing plates from the sheet-fed printing press according to the invention allows maintenance and cleaning work to be carried out on the printing units outside the area of ​​the sheet-fed printing press.

[0033] Viewed in the transport direction of the printed sheets, a drying device or curing device and / or an extraction device is preferably arranged downstream of the printing formless printing device, wherein the drying device serves to dry the printing ink applied via the printing formless printing device and the extraction device serves to extract solvent vapors from the printing ink applied via the printing formless printing device.

[0034] The formless printing unit is pivotably arranged in the area of ​​the feeder 11, preferably on a pivot arm that engages a side frame of the feeder or the first printing unit. This allows free access to the feeder 11 for setup work. Reference symbol list 10 sheet-fed printing press 11 investors 12 printed matter 13 Lacquer Works 14 outriggers 15 stacks of booms 16 reversing cylinders 17. Formless printing device / Installation position 18. Formless printing device / Installation position 19 Investment table 20 investor stacks 21 Preemptors 22 sheet-fed printing press 23 printed matter 24 Lacquer Works 25 drying equipment 26 sheet-fed printing press 27 Sheet-roll cutting device 28 rolls 29. Formless printing device / Installation position

Claims

Sheet-fed printing press, with a feeder (11) for feeding sheets to be printed into the sheet-fed printing press, with at least one printing unit (12; 23) and / or coating unit (13; 24) for printing the sheets with a static print image identical for all sheets, with a delivery unit (14) for ejecting printed sheets from the sheet-fed printing press, and with at least one formless printing unit (17, 18; 29) integrated into the sheet-fed printing press for printing the sheets with a variable print image, wherein the formless printing unit or units (17, 18; 29) is integrated into the sheet-fed printing press in the area of ​​the feeder (11), and wherein the formless printing unit or units (17, 18;29) the printed sheets in the area of ​​the feeder (11) are printed from above, characterized in that the feeder (11) is designed as a single-sheet feeder, that the or each printing formless printing device (18) is integrated into the sheet-fed printing machine (10) above a feed table (19) of the single-sheet feeder, in the area of ​​which the printed sheets are guided on an underside of the same by at least one suction belt, wherein a sensor is provided for detecting the leading edge and side edge of each printed sheet, and that the variable print image is applied inline to the printing of the printed sheets with the static print image, wherein the variable print image is applied before the printing of the printed sheets, wherein in a control device of the printing formless printing device (17, 18;29) at least one characteristic curve is stored which depends on substrate characteristics such as the basis weight and / or the fiber direction and / or the stiffness of the printed sheets, wherein the printing formless printing unit (17, 18; 29) can be controlled on the basis of these characteristic curves when the transport speed of the printed sheets changes during the feeding of the printed sheets into the sheet-fed printing press via the pre-gripper (21). Sheet-fed printing machine according to claim 1, characterized in that the feeder (11) is designed as a roll-sheet feeder (27, 28). Sheet-fed printing machine according to claim 2, characterized in that the or each printing formless printing device (29) is integrated into the sheet-fed printing machine (10) in the area of ​​a sheet-roll cutting device (27) of the roll-sheet feeder (27, 28) in such a way that the printed sheets can be printed on a top side of the printing formless printing device (17, 18, 29). Sheet-fed printing machine according to one or more of claims 1 to 3, characterized in that the or each printing formless printing device (17, 18, 29) is designed as an inkjet printing device or laser printing device, wherein the printed sheets can be printed over the entire format width and / or format length by the or each printing formless printing device (17, 18, 29). Sheet-fed printing press according to claim 4, characterized in that the or each printing formless printing device (17, 18, 29) has several inkjet printheads or laser printheads arranged side by side in the direction of transport of the printed sheets and / or several inkjet printheads or laser printheads arranged one behind the other in the direction of transport of the printed sheets, which are interconnected on the control side. Sheet-fed printing press according to one or more of claims 1 to 5, characterized in that printing formless printing devices (17, 29) print the printed sheets individually before the static printing of the same in the printing unit or each printing unit and / or in the coating unit or each coating unit. Sheet-fed printing press according to one or more of claims 1 to 6, characterized in that the or each printing formless printing device (17, 18, 29) can be removed from the sheet-fed printing press in such a way that the or each printing formless printing device (17, 18, 29) can be used on another sheet-fed printing press or within the same sheet-fed printing press at different installation positions. Sheet-fed printing machine according to one or more of claims 1 to 7, characterized in that a drying device and / or a suction device is arranged downstream of the or each printing formless printing device (17, 18, 29) in the transport direction of the printed sheets. Sheet-fed printing machine according to one or more of claims 1 to 8, characterized in that the or each printing formless printing device (17, 18, 29) is pivotably arranged in the area of ​​the feeder (11).

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