EP2055478A2 - System for creating tactile structures on printed products - Google Patents

Abstract

The press has print units arranged one behind the other, and lacquer units arranged upstream, downstream, or between the print units. Print layers expandable by radiation are applied on print sheets (33) before a printing process or in the print units and/or the lacquer units. Laser marking devices (14) are arranged, and impact on the print sheets guided by a conveying system in such a manner that tactile samples are created on the print sheets. The print sheets are stored in a sheet delivery unit on a delivery stack.

Description

The invention relates to a marking device for a printing machine, in particular a laser marking device, for the individual marking of printed sheets or individual uses on the signatures according to the preamble of claim 1.

Equipment for marking printed sheets or individual printing benefits within sheetfed presses have long been known.

In the EP 0737 572 B1 It is proposed, for individual printing of the individual sheets, for example with a barcode, laser or inkjet printer assign a sheet guiding drum, which is arranged in front of the first printing unit, between two printing units or after the last printing unit. The sheet is fixed with elaborate holding means, for example by suction, which detect the sheet end on the drum. This solution found requires a high technical effort and retrofitting existing machine configurations is very difficult.

In the DE 197 04 003 A1 It is proposed to arrange laser printing devices after the printing nip of a printing unit, wherein the sheet is provided with individual identifications as directly as possible after the passage of the printing nip, which is formed by the rubber and impression cylinder, by the sheet mounted on laser printing devices, the distance to the impression cylinder are to be passed. The disadvantage of this solution found that the freshly printed sheet must be fixed at rigid materials on the impression cylinder to prevent lifting of the sheet end and striking the laser printing device. Such sheet guiding devices are expensive and can not always avoid smearing. In addition, they can the bow end in a rigidly arranged sheet guiding solution not completely fix on the impression cylinder, as a collision between the grippers of the sheet leading impression cylinder, which protrude beyond the lateral surface of the impression cylinder, must be avoided. However, a slight lifting leads to a shift of the focal plane, which can cause a broadening of the laser marking. For this purpose, bow guide rollers are proposed, which are provided with a color-repellent coating. However, these can also collide with the grippers and thus swing. Alternatively, they would have to be dug. Both solutions are not practical, since even a slight relative movement, even with a color-repellent surface of the sheet guide roller, can lead to smearing of the fresh color layer.

Another technical and economic counter-argument to that in the previously cited patent and published patent applications is that the lasers must be arranged relatively close to the sheet-guiding cylinder so that the operating space of the machine is not restricted. Therefore, several laser printing units are necessary around the entire width of the sheet in order to be able to provide the entire sheet with individual codes. This requires a higher control and set-up time, since depending on the distance between laser and printed sheet, the laser must even be moved to a dedicated work position. The cited prior art proposes for the positioning of the laser printing devices, a manual adjustment of the position of the laser printer, a procedure that is no longer accepted by the market in the age of highly automated set-up operations.

In the DE 203 03 574 U1 It is described that, in connection with an image processing system, incorrectly recognized signatures or printing benefits are marked or inscribed by a printing device. Mention should also be made here of a laser printing device, which may also be associated with the boom of a sheet-fed press.

The object of the invention is a fast and cost-optimal laser marking device to create for printed sheets, which requires no additional setup effort for the laser unit or the laser units.

This object is achieved in a device having the features according to claim 1.

Meaningful developments of the invention will become apparent from the dependent claims.

According to the invention, it is proposed to arrange one or more laser devices in the area of sheet conveying or above the installation space of a sheet delivery of a sheet-fed printing press. Preferably, a sheet-fed offset printing machine is used as the carrier for the application.

Advantageously, the task setting is fulfilled by a coordinate-controlled, programmable system, in particular a scanner system in conjunction with a laser beam source. By a pulsed behavior of the beam source, it is preferably possible to generate individual points or lines in any desired arrangement on the sheet. The palpable structures are in this case achieved by an applied to the substrate flatulent paint or paint or other material that has been applied to the substrate before the printing process. This material expands at points exactly where it comes into contact with the beam emitted by the system according to the invention, in particular laser radiation.

The invention is explained in more detail below with reference to drawings.

Figur 1

eine Anordnung in einem Bogenausleger,

Figur 2

Anordnungen in einer Bogenoffsetdruckmaschine und

Figur 3

die Anordnung einer Lasermarkierungseinrichtung.

Show in it

FIG. 1

an arrangement in a sheet delivery,

FIG. 2

Arrangements in a sheet-fed offset printing press and

FIG. 3

the arrangement of a laser marking device.

In FIG. 1 a sheet delivery 1 is shown, which adjoins a sheet-fed printing machine for forming a sheet stack of printed sheet 33 in a display 4. In the working space of the sheet delivery 1 (space limitation 3) a laser marking device 14 not shown here is provided. This is located inside a funnel-shaped foreclosure 2, which ensures that the laser beam can not endanger the health of the staff. In addition, a working distance for the deflection of the laser marking device 14 is created, whereby the laser beam and the laser beams can be deflected over the entire sheet width to require as few individual laser units.

In FIG. 2 is a sheetfed offset printing machine with a feeder 5 for sheet feeding, printing units 6 and 7 for printing inks on the sheet 33 and a coating unit 8 between the printing units 6, 7 for coating the sheet 33 and the boom 1 for stacking the sheet 33 shown. The printed sheets 33 are guided in the sheet-fed offset printing press on counter-pressure cylinder 20, sheet transport drums 21 and a chain conveyor system 22 to grippers through all stations of the processing and finally stored on the delivery pile. This illustration shows a minimal configuration of a sheet-fed press. This can contain more than two printing units and more than one coating unit, which can also be arranged in different order.

In the area of the path of sheet conveying with gripper systems revolving on cylinders within the sheet-fed offset printing press so illustrated, laser devices 9 to 13 can now also be assigned in different alternative arrangements directly leading cylinders (impression cylinder 20) or drums (sheet transport drum 21) or gripper carriage systems (chain conveyor 22) , Here, the laser marking devices 9 to 13 for labeling can be directed in a well-focused manner to the previously printed in printing units 6, 7 and / or coating units 8 printed sheet 33, since the cylinders and drums usually solid surfaces or the bow guide serving mating surfaces, which allow a good positioning of the sheets 33. In the sheet delivery 1, the assignment can be done by means of suction for the free-flying there held on the chain conveyor 22 sheet 33.

The arrangement of the laser marking devices 9 to 13 can be selected such that a plurality of laser units are arranged across the width of the cylinders or drums. Then, the distance to the respective required for the marking support surface of the sheet 33 can be selected low, so that a small size can be achieved.
However, the arrangement of the laser marking devices 9 to 13 can also be selected such that only one or two laser units are arranged across the width of the cylinders or drums. Then, the distance to the respective required for the marking support surface of the sheet 33 can be chosen so large that a safe sweeping the entire sheet width in the marking can be achieved.

This is in FIG. 3 the Einstrahlprinzig a laser marking device on an impression cylinder 20 shown. The laser marking device consists of a laser unit 30, which is optically connected to a scanner 31. The scanner 31 is an optical device for arbitrarily controllable, possibly periodic deflection of a laser beam 32 acts on an imaging area of a printing sheet 33. In this case, the focusing of the laser beam 32 to the respective substrate (sheet 33) is constantly adjusted depending on the distance. From the laser unit 30 laser light is transmitted to the scanner 31 and radiated from there as a controlled and optionally on the signature 33 oscillating laser beam 32.
The scanner 31 is arranged for this purpose in a sufficiently large possibly adjustable distance above the counter-pressure cylinder 33 carrying the printing sheet 20. Thus, the maximum necessary pendulum angle of the laser beam 32 with respect to the maximum possible width of the sheet 33 is not too large, so that the control is limited to the movement to acceptable speeds and the adjustment control can run optimally for focusing.
As a result of the movement of the laser beam 32, the latter can cover the full width of the printed sheet 33 as required and writes or processes the desired pattern in the corresponding surface areas on the surface as a result of its pulsed irradiation.
If a plurality of laser marking units are arranged next to one another at a station for marking or processing the surface of the printed sheet 33, corresponding relationships result, wherein the distance of the scanner 31 from the printed sheet 33 can then be selected correspondingly smaller.

The printed sheets 33 are thereby exposed to one or more laser marking devices 9 to 13 for processing. The laser marking devices 9, 11 and 12 are associated with counter-pressure cylinders 20 on which the printed sheets 33 are securely guided. The laser marking device 10 is associated with a sheet transport drum 21 and irradiates the printing sheet 33 from the inside thereof, wherein the sheet 33 is optionally pneumatically guided on a sheet guiding surface (sheet guide path) opposite the sheet transport drum 21. Finally, the laser marking device 13 is still associated with a chain conveyor 22 to the sheet delivery 1 out. Each of the mentioned laser marking devices 9 to 13 can consist of one or more laser units 31 and can be arranged variably and adjustably on the respective element guiding a sheet. Thus, each point of the printing sheet 33 can be irradiated during its transport through the printing press by means of a laser beam 32. Here, the sheet movement and speed in the movement of the laser beam 32 is included for the processing.

In another application, one or more inlet openings may be provided on the sheet delivery 1 in the upper Verschutzung through which the laser beam or the laser beams enter the space of the sheet delivery 1 and guided there by the display gripper systems sheet 33 for the purpose of labeling or marking Sheet 33 can hit or can.

Preferably, the surface of the printing sheet 33 is scanned for the purpose of labeling or marking only by one or two laser beams.

The assembly of the laser marking device 14 above the installation space of a boom of a sheet-fed press accordingly FIG. 1 allows a deflection of the laser beam over the entire width or portions of the sheet 33 with only small adjustment movements of the deflection optics or deflection optics (scanner) of the laser. These small paths can be done much faster than the relatively large adjustment paths that would be required if the laser were placed within the space of the cantilever. Due to the fast, small movements of the deflection optics writing and marking work on the entire sheet 33 with one or only a few laser units in the laser marking device 14 can be performed. An arrangement that would be chosen closer to the sheet 33 requires higher adjustment paths and times, so that in a complex marking the writing speed according to the current state of the art is not sufficient and therefore the number of laser units would have to be increased within the Laserermarkierunsgeinrichtung 14. For the marking or labeling of the sheet 33, only a relatively small time window can be used, which lies between the leading and the returning gripper system of the boom. In addition, a strong trailing or leading the laser beam relative to vertical incidence position would generate an angle of incidence, which leads to a deterioration in the quality of the writing image. The laser beam is widened and the line width thus wider. It is therefore also necessary for quality reasons to sweep the entire sheet width in a relatively small time window. The proposed solution according to the invention makes this possible in the best way.

The assignment of a laser marking arrangement 13, 14 to the sheet delivery 1 of a sheet-fed printing press further has the advantage that the printing sheet 33 in the straight part of the sheet guide tracks is guided flat and can be fixed by the pneumatic working sheet guiding devices on this by negative pressure. Elaborate setup work and additional sheet guiding elements are not required in the inventive solution.

Additional set-up times are not incurred since neither sheet guiding devices nor laser marking devices 9 to 14 need to be equipped and cumbersomely adjusted. The laser marking devices 9 to 14 are mounted in a fixed position and the desired marking location is controlled by the movement of the laser optics for deflecting the laser beams. In the event that should not be marked, the laser beam (s) are switched off and turned on for marking or the laser beam is deflected so that it does not hit the printing sheet 33 and is directed onto the printing sheet 33 when a marking is to be made.

The laser (s) could theoretically also be mounted on a carriage or a linear drive or a plurality of linear drives which move the laser (s) over the machine width or, if appropriate, also in the X, Y direction over the printed sheet 33. However, these drives require special protection against dust and powder, as it often occurs in the area of the sheet delivery 1. In the FIG. 1 shown fixed position high above the space of the sheet delivery 1 but ensures a low tendency to fouling. The lack of moving parts that are exposed also increases the robustness of the overall system.

A further advantage of a position of the laser marking device 14 far above the installation space 3 of the sheet delivery device 1 is that contamination of the laser optics by dust and powder, which inevitably occurs in the sheet delivery device 1 of a sheet-fed machine, can be further reduced in which in the hopper, A small overpressure prevails, which closes off the beam area of the laser and directs the air out of the funnel towards the interior of the laser Cantilever stream. This largely avoids the penetration of dust and powder. The overpressure can be generated in a known manner by fans or fans, which blows air into the hopper building space. This advantage also applies to the corresponding arrangement of the laser marking devices 9 to 13 on the printing or coating units 8.

The arrangement above the boom 1 requires as well as in the printing 7 or Lackwerken 8 for safety considerations shielding the beam range of the laser relative to the environment to avoid leakage and eventual deflection of the laser beam and contact of a machine operator with the laser beam. Any contact with powerful laser units can cause serious physical damage, which must be avoided at all costs.

Such shielding may be accomplished by shielding the beam region of the laser by a metallic or polycarbonate cladding or other type of protective device suitable for laser absorption. Here, the type of shielding on the type of laser and the radiated wavelength from him suitably match.
The Ummantelung of the beam area must be designed so safety that a disassembly or opening leads to the immediate shutdown of the laser or the laser. An access or access or opening a protection of the boom installation space (as well as the installation space on a printing or coating unit 8 8 as in FIG. 2 ) must also lead to a shutdown of the laser. In this case, the protective devices must be protected against opening, which were previously secured only by screws. This can be done by special screws or electrical contacts that interrogate the presence of the protection.

The laser beam (s) may interact with an IR-reactive or a UV-reactive material previously applied to the substrate (print sheet 33). Such a material may be an IR-reactive or a UV-reactive printing ink or a varnish in which a volume change by the laser beam is brought about. The material may also be a printing ink or a varnish which has elements which are swellable under the action of heat and which leads to haptically sensible structures and / or color changes in the region which is swept by the laser beam.

This can be in the devices after FIG. 1 or FIG. 2 In particular, a Braille font embossment are generated. As a coordinate-controlled, programmable system, the laser beam is capable of writing any desired patterns on the printed sheets 33 to be processed. Here, a kind of scanner system is provided. By pulsing the laser beam, a dotted pattern can be generated. The puncture may then be applied to a signature 33 in any manner, as well as a line pattern.

Such a structure may be provided with a protective layer, such as a lacquer layer, prior to formation in further leading printing units or coats 8, so that it is protected beneath this layer and thus becomes more resistant.

Such a structure produced by means of the laser beams on the printed sheet 33 can also, after being produced in further downstream printing or coating units 8, be provided with a protective layer, e.g. a lacquer layer are provided, so that the structure is effectively protected.

The laser itself can be a CO2 laser, a diode laser, an excimer laser or a YAG laser. Also suitable are fiber or disk lasers. In principle, however, any type of laser is suitable, which allows to work with suitable controls an inflatable layer (irradiate) without destroying them.
The treatment by irradiation can trigger physical or chemical reactions in the corresponding layer.
The processing takes place, for example, in IR-reactive systems by the action of heat, which leads to the swelling of the irradiated layer elements.

On the other hand, the processing takes place in UV-reactive systems by triggering a chemical reaction, which leads to selective polymerization and thus to the puffing of the irradiated layer elements.

The proposed solution is suitable for creating tactile structures in the production of printed products for the graphic arts industry. Braille in particular (braille on pharmaceutical packaging). By integration into the printing process, the creation of the structures that can be sensed can take place during the printing process.

According to the previously known state of the art, only embossing methods with die and male are known, but they must be regarded as inflexible and profitable only after a high circulation of printed products. Furthermore, the embossing is produced in a work step downstream of the actual printing process.

The great advantage of the system is its high flexibility, since the structures are generated by a coordinate-controlled, programmable system. In addition, it is an inline method, which eliminates the downstream step of embossing and the necessary embossing plant.

It is thus a coordinate-controlled, programmable system, in particular a scanner system in conjunction with a laser beam source, provided. By pulsed driving the radiation source individual points or lines can be easily generated in any order on the sheet 33. The desired tactile structures are produced by means of the inflatable paint applied to the substrate or a corresponding lacquer or other suitable material which may have been applied to the printing sheet 33 before the printing process. The respective coating expands at points exactly where it is contacted by a laser marking device 9 to 14 emitted laser radiation.

The system according to the invention of the laser marking devices 9 to 14 can be installed completely flexibly depending on the available space before, in or after a printing or coating unit 8 of a printing press or in conjunction with a delivery 1 of the printing machine, in particular a sheet-fed offset printing press. There is the possibility of applying a protective film to the structure produced by the system by means of a subsequently applied paint or lacquer layer or to produce the structure in or below a previously applied coating of paint or lacquer.

LIST OF REFERENCE NUMBERS

1

Boom of a sheetfed press

2

Funnel-shaped foreclosure of the laser beam

3

Space limitation of the boom

4

Delivery (stacking area) of the jib

5

investor

6

printing unit

7

printing unit

8th

coating unit

9

Laser marking device

10

Laser marking device

11

Laser marking device

12

Laser marking device

13

Laser marking device

14

Laser marking device

20

Impression cylinder

21

Sheet guide drum

22

conveyor system

30

laser unit

31

scanner

32

laser beam

33

sheet

Claims (18)

Sheet-fed printing machine with one or more successively arranged printing units, with one or more the printing units before, between or downstream coating units and with a delivery pile having sheet delivery, wherein the sheets within the sheet-fed press in the course of the work process by means of conveyor systems on rotating gripper systems in the gripper closed by the printing units, coating units and the sheet delivery are conveyed and deposited in the sheet delivery on the delivery pile, characterized by
in that prior to a printing process or in one or more printing units (7) and / or coating units (8) of the sheet-fed printing press radiation-expandable printing layers are applied to the printing sheet (33) and that one or more laser marking devices (9 to 14) are arranged on the printed sheet (33) conveyed by the conveying system (s) (20, 21, 22) acts or acts such that tactile patterns can be generated on the printing sheet (33). Sheet-fed printing machine according to claim 1, characterized in that the conveyor system consists of corresponding to the number of printing units arranged impression cylinders (20) and sheet transport drums (21) and that the laser marking devices (9 to 12) one or more impression cylinders (20) or sheet transport drums (21) before -, or are subordinate to. Sheet-fed printing machine according to claim 1, characterized in that the conveyor system consists of connected to the sheet delivery (1), the sheet (33) carrying rotating gripper systems (22) by means of which the sheets (33) can be stored in the gripper closure on a delivery pile, wherein the Sheet delivery (1) has an upwardly closed space (2), which encloses the area of the conveyor system (22) and that the laser marking devices (13, 14) are arranged in connection with the sheet delivery (1). Sheet-fed printing machine according to claim 2 or 3, characterized in that the laser marking devices (9 to 14) of a conveyor (20, 21, 22) are assigned such that they for conveying the printing sheet (33) in a defined position relative to the respective laser marking device (9 to 14) is equipped. Sheet-fed printing machine according to claim 2 to 4, characterized in that the conveyor is a counter-pressure cylinder (20) or a full-surface sheet transport drum (21) or a sheet guide track or a Bogenstraffeinrichtung. Sheet-fed printing machine according to claim 1 to 5, characterized in that a sheet-fed press according to the principle of offset printing or flexographic printing or gravure printing or screen printing is used. Sheet-fed printing machine according to claim 1 to 6, characterized in that each laser marking device (9 to 14) one or more laser units (30) as CO2 laser and / or excimer laser and / or YAG laser and / or diode laser and / or a Laser of other types, which is suitable for the selective irradiation of an intumescent layer. Sheet-fed printing machine according to claim 7, characterized in that each laser marking device (9 to 14) has one or more scanners (31), by means of which a laser beam (32) generated by the laser unit (30) with respect to a printed sheet (33) to be irradiated. including the sheet movement at any point on the surface of the sheet (33) is controllable and focusable. Sheet-fed printing machine according to claim 1 to 8, characterized in that the marking on the printing sheet (33) takes place by a local flattening of inflation elements contained in the printing ink or lacquer layer is carried out by the laser. Sheet-fed printing machine according to claim 9, characterized in that the marking on the printing sheet (33) takes place in that by the laser embossing of the surface by local flattening of inflation elements contained in the printing ink or lacquer layer. Sheet-fed printing machine according to claim 8 to 10, characterized in that the flatulence takes place by an action on physical way. Sheet-fed printing machine according to claim 11, characterized in that the flatulence takes place by the action of heat. Sheet-fed printing machine according to claim 11 or 12, characterized in that the flatulence is carried out by irradiation of an IR-reactive layer by means of a laser with a high IR light component. Sheet-fed printing machine according to claim 8 to 10, characterized in that the flatulence takes place by an action by chemical means. Sheet-fed printing machine according to claim 14, characterized in that the blowing is carried out by polymerization. Sheet-fed printing machine according to claim 14 or 15, characterized in that the flatulence is effected by irradiation of a UV-reactive layer by means of a laser with a high proportion of UV light. Sheet-fed printing machine according to claim 1 to 16, characterized in that the marked surface is sealed or coated. Sheet-fed printing machine according to claim 1 to 16, characterized in that the markings in a coating below a sealing or protective coating forming surface of the printing sheet (33).

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