DE102008035484A1 - Plasma treatment during printing - Google Patents

Abstract

The invention relates to a sheet-fed printing press, having a sheet tray (10) for sheets to be printed, having at least one printing unit for printing the sheets, having a flange for discharging printed sheets, and having at least one unit (16, 22) for surface modification of a surface of the printed sheets in order to increase the surface tension and thus the wetting ability of the same using printing ink. According to the invention the, or each, surface modification unit (16, 22) is integrated into the sheet-fed printing press in the region of a plasma treatment module (29) connected downstream of the sheet feed.

Description

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

Sheetfed are used for printing sheet-shaped substrates, so-called printed sheets, wherein to be printed sheet in the area of an investor in a Printing process introduced and in the range of a boom from the printing process be discharged. Between the investor and the boom of Printing press are positioned several printing units, with each printing unit a partial print image in a special ink or a different type Coating be applied to the substrate.

The printed sheets can be made from a variety of different Be made of materials. Should be trained as plastic films or be printed with a plastic coating printed sheets, so it should be noted that in particular UV-curing printing inks or water-based inks only very badly on the sheet be liable. This is especially the case when printing sheet out hard-to-print substrates or corresponding coatings like polypropylene (PP, HDPP, LDPP) or polyethylene (PE, HDPE, LDPE) to be printed. So it is with these plastics to materials, which due to their production a low surface tension and / or have a low polarity. This results when printing with UV-curing inks or varnishes or poor wetting with water-based inks or varnishes Such sheet and / or poor adhesion of the ink respectively Paints on the sheet.

to Increasing the surface tension of substrates and thus to improve the wetting ability or Printability of the same, it is already known from the prior art known, the substrates to a so-called corona treatment undergo.

So revealed the DE 102 32 255 A1 a device for treating the surfaces of printing substrates in printing presses, wherein the printing substrate in the region of a corona electrode with discharging processes originating charge elements, such as. As electrons, is bombarded. Here, a metallic or conductive printing cylinder, on which the printing material is guided on passing the corona electrode, serves as the counterelectrode, so that an electrical discharge, which is carried out between the corona electrode and the printing cylinder serving as the counterelectrode, passes through the printing substrate through. In this case, a small distance of the corona electrode from the substrate in the order of 0.5 mm must be maintained, so that accessibility is severely limited. In addition, there is a risk that the printed sheets are damaged when touching the corona electrodes by marking strips, at least on their surface. Furthermore, for a good distribution of charge potentials on the substrate a high density of corona electrodes is necessary because the charges are scattered only weakly in this system.

The DE 20 2004 008 285 U1 discloses an atmospheric pressure plasma processing tool for wide workpieces in which electrical discharges occur between electrodes and counter electrodes formed as nozzles. In such a device, the electrodes and the counter electrodes formed as a nozzle are positioned on one side of a substrate to be treated so that the electrical discharge does not occur through the substrate. Rather, in such a device, a plasma generated during the electric corona discharge is conducted by means of a gas, namely with the aid of compressed air, onto the surface of the substrate to be treated. Instead of compressed air, other gases, for example nitrogen, can be used to transport the plasma in the direction of the substrate.

Of these, Based on the present invention, the problem is based to create a novel sheet-fed press.

This Problem is due to a sheet-fed printing machine according to claim 1 solved.

According to the invention the or each surface modification device of Substrate in the area of a module after the feeder in the sheet-fed press integrated.

The or any device arranged according to the invention for surface modification preferably produces a plasma on the one side of a printing material associated therewith. The printing material is therefore not between the electrodes, between which is an electrical charge for plasma formation, positioned. That's about electrical discharges from air or others Gases, such as nitrogen, generated plasma is using of overpressure on the respective surface of the Substrate passed. The integration of the device for surface modification in the area of the investor is particularly in terms of space requirements advantageously possible.

According to an advantageous embodiment of the invention, the investor is designed as a bulkhead feeder and has an investment table, on which the sheet as a scale flow to a Sheet system for alignment and separation of the sheets are transportable, wherein the means for surface modification in the area of a sheet following the sheet transport cylinder is integrated, in which the surface of the sheet to be modified is freely accessible.

preferred Further developments of the invention will become apparent from the dependent claims and the description below.

embodiments of the invention are, but are not limited to, explained in detail with reference to the drawing. Showing:

1 : a detail of a sheet-fed printing press from the area of its sheetfed,

2 : a first integrated device for surface modification in width view,

3 : a detail of the view according to 2 with a plasma generating device,

4 FIG. 2: a representation of a plasma generation plant for the device according to the invention according to a second design, FIG.

5 a first inventive arrangement within a sheet-processing printing machine and

6 a further arrangement according to the invention.

Hereinafter, the present invention will be described with reference to FIG 1 to 4 described in more detail.

1 shows a schematic section of a sheet-fed press in the area of a sheet plant 10 , In the field of sheetfed 10 printed sheets are provided, which are held in a sheet feeder in the form of a stack, separated and via a feed table 11 fed to a first printing unit of the sheet-fed press. In the illustrated embodiment, the sheet system 10 connected to a shed feeder, which means that in the area of the investment table 11 sheet 12 be transported as a scale flow with mutual overlap. 1 shows schematically two mutually partially overlapping sheets 12 a shingled stream. At the transport direction (arrow 13 ) the printed sheet 12 seen at the front end of the investment table 11 an alignment of the separated sheets takes place 12 not shown alignment marks and a sheet feed the sheet 12 with the help of a pre-gripper 14 , The pre-gripper 14 captures a previously aligned sheet 12 at its forward in the transport direction section, pulls it from the investment table 11 and hands it over to a first cylinder 15 the printing press. Usually this is the first cylinder 15 executed in the manner of a so-called investment drum.

In the 1 Configuration shown can also be performed within a so-called investor-investment module. In this case, then the upstream of a sheetfed press feeder (Schuppenanleger) with the devices for sheet feeding to the sheetfed press, as a sheetfed 10 have been carried out in a single unit. Within this unit, the arrangement according to the invention can also be used.

In the area of the bow plant 10 The sheet-fed press is a device 16 for surface modification of the printed sheets to be printed 12 integrated. To 1 is the device 16 for surface modification in the sheet system 10 in the area in front of the so-called pre-gripper 14 arranged where an orientation of the separated by a stack sheet 12 before being fed to the sheetfed press. There, the printed sheet to be processed is exposed so that its surface is completely accessible. So can the prints 12 be surface modified over their entire surface.

The device 16 for surface modification of the substrates 12 by means of a plasma is preferably as in 4 shown executed. So has the decor 16 of the 4 over several electrodes, in two consecutive rows 17 respectively. 18 are grouped. Inside each of these two rows 17 and 18 In the embodiment shown in each case four electrodes in a common housing 19 arranged, with nozzles 20 of the housing 19 Counterelectrodes for electrical discharge within the device 16 form. The number of rows and the associated number of electrodes per row are listed here purely by way of example. The device 16 is according to 1 on a crossbar 26 stored.

As 4 can be taken, are the nozzles 20 or the electrodes, not shown, of the two rows 17 and 18 aligned such that in the middle between two adjacent electrodes or nozzles 20 one row an electrode or nozzle 20 an adjacent row is positioned. This will produce an array of electrodes or nozzles 20 formed, with the help of which the substrates 12 can be uniformly subjected to surface modification in the area of their surface.

At the in 4 schematized Facility 16 For surface modification, the required for plasma formation electrical discharge takes place within the housing 19 , wherein the plasma formed in this case with the aid of a flowing out under pressure carrier gas, for. B. compressed air 21 , about the nozzles 20 in the direction of the printed sheets to be treated 12 is directed. To do this, grab the case 19 the two rows 17 and 18 Compressed air connections 21 to the compressed air 21 into the housing 19 initiate and so the plasma formed during the discharge together with overpressure through the nozzles 20 out of the case 19 lead out and towards the printed sheet 12 to promote.

The nozzles 20 are preferably designed as slotted nozzles and have seen in cross-section parallel to the conveying plane and transversely to the direction of movement of the sheet 12 over a larger dimension than in the direction of movement of the sheet to be treated 12 , This allows a particularly uniform treatment of the sheet 12 will be realized.

At the device 16 according to 1 takes place, as already mentioned, the electrical discharge completely within the housing 19 the two rows 17 and 18 , so that there is no danger of short circuit with the other components of the sheet-fed press. In this case, then at the other modules, eg. B. at the transfer gripper 14 , no changes are made, which is preferred for cost reasons.

Alternatively, it is also possible to use the device for surface modification as in 2 and 3 shown to execute. To show 2 and 3 An institution 22 for the surface modification of substrates, wherein electrical discharges between each two outer electrodes 23 (please refer 3 ) respectively. Between the electrodes 23 a plasma forms 24 out, with the supply of air under an overpressure as compressed air 25 on a surface of the printed sheet to be treated 12 can be directed. The compressed air 25 In doing so, it takes along the charge carriers desired for surface modification and distributes them over the surface of the printed sheet to be treated 12 ,

Since at the in 2 and 3 illustrated embodiment of the device 22 for surface modification the electrodes 23 open, assemblies of the printing press, which are in the field of equipment 22 coated to avoid the risk of short circuits due to discharge sparks leaking from the electrodes.

For improved handling it is envisaged that the facilities 16 respectively. 22 for surface modification of printed sheets by means of a holder (here about a traverse 26 ) are arranged in the contact area of the sheet-fed printing machine. At this point they can be pivoted into a working position on the bow path. For maintenance on the printing press, the facilities can 16 respectively. 22 also at the Traverse 26 or with the crossbar 26 be executed swiveled out of the investment area.

The units thus integrated in the contact area of the sheet-fed printing machine 16 . 22 for surface modification of printed sheets can finally still by a corresponding protection 27 be disguised. By means of the protection 27 can via a suction unit 31 the removal of the resulting hot process gases are made possible by means of a negative pressure. This avoids environmental pollution on site and undue heating of the units 16 respectively. 22 through the work process can be stopped.

In 1 is in the field of sheetfed 10 An institution 16 positioned for surface modification, by means of which the printed sheets 12 can be treated in the region of an upper side or surface with respect to the transport plane.

If the sheets are to be printed on both sides, it is also possible to have one set each 16 For surface modification, position on both sides of the substrate. So z. B. a second device for Oberflächenmo difikation in 1 below the alignment area of the bow system 10 or below the cylinder 15 be positioned and so take over the surface modification of the substrate in the range of the second side.

Likewise, the second surface modification device in the area of a sheet turning device can be integrated into the printing machine. In this case, the second device for surface modification is preferably arranged in the region after the application of the sheet where the printed sheet 12 turned upside down and thus its second side is upwards. Then the device can 16 be assigned to the surface modification above the transport plane of the sheet path.

additionally may be a third surface modification device be integrated in the sheet-fed press before a coating unit.

It is also possible to integrate the device for surface modification exclusively in the area of a sheet turn in the sheet-fed press. This is advantageous if one-sided coated printing sheets are used, the first of the uncoated side and after the sheet application of the coated side be to print works.

As well The device for surface modification can only be integrated in the sheet-fed press before a coating unit. This is then advantageous if the already printed surface the printed sheet for a final finishing treatment, z. B. by applying a shiny or protective Coating, to be modified.

In the facilities 16 . 22 For surface modification, units are used in which the electrical discharge does not occur through the substrate. Here are electrodes and counter electrodes, between which each electrical discharges take place, positioned on the same side of the sheet to be treated. The facilities 16 . 22 have a distance of between 5 mm and 10 mm from the respective surface of the printed sheets.

According to the invention the arrangement further features.

The device 16 respectively. 22 for modification of the surface of printed sheets is either provided in addition to the power supply with its own control or may be coupled to the machine control in such a way that it is adaptable in their behavior to the printing process. Thus, at least time or duration or time and duration of the plasma generation at the device 16 respectively. 22 be adjustable. The settings may also be tunable with respect to the power stroke of the sheetfed press.

The device 16 respectively. 22 For generating the plasma used in the modification of the sheet surface can thus be limited in an efficient manner to the time during the supply of a sheet in the sheet-fed press. This prevents uncontrolled loads from entering the press or the sheet feeder 10 be sprinkled into it.

Furthermore, the surface modification by means of the device 16 . 22 be done so that areas of the substrate surface are recessed both transversely and longitudinally to the feed direction. This is due to the described design of the device 16 from a series of discharge units.

Farther The power of plasma generation can be adjustable to the necessary in relation to the desired pressure conditions Amount of free radicals in a customizable plasma for z. B. different settings of surface tensions to achieve in the modification of the surface of the sheet. For this purpose, the power of the discharge units is variably controlled, so that the amount of reactive plasma gas can be specifically influenced can.

Essential is that the strength of the surface modification of printed sheet through the plasma on the respective substrate adjustable is. This results in differences between different substrates, Because these are different with the free radicals from the plasma react. This reaction can be for the same materials due to variable manufacturing processes, transport and storage conditions be equally variable. Therefore, the strength of surface modification becomes specifically influenced, with the main influence variable the strength of the plasma is. But continue to affect also the duration of the plasma action, the type of gas used and the Pressure of the blast air flow at the nozzles off.

After all can also be the strength by means of the controller the surface modification of the sheet to the transport speed adjust the sheet. This can be done during the printing process with increasing machine speed and thus shorter the duration of exposure of the plasma becomes the strength of the plasma be raised, so that even in a shorter time always the same amount of reactive plasma gas is available. As well can the overpressure to imprint the plasma gas be lifted onto the substrate.

According to 5 is a device according to the invention 16 for generating a plasma an impression cylinder 30 associated with a bow leading module, creating as a treatment module 29 trained device in combination with a sheet-fed press. The treatment module 29 is between the bow plant 10 and a first printing unit 40 arranged. Instead of the first printing unit 40 can also be provided a coating unit. The printsheet 12 are used to carry out further processing via the impression cylinder 30 of the treatment module 29 and sheet transport drums 28 through to the treatment module 29 following printing works 40 . 50 guided.

Such a treatment module 29 In addition, it can also be arranged in combination with a lacquer module or a differently configured unit for the treatment (such as embossing, creasing, cutting) of substrates in the inline method.

Alternatively, a treatment module 29 be preceded by a fully configured as a varnishing sheetfed press, in which case in conjunction with the treatment module 29 according to subordinate flexographic printing works are provided.

• – Drucken mit konventionellen oder Anilox-Druckwerken,
• – Lackieren bzw. Beschichten,
• – Folienapplikation,
• – Prägen, Stanzen, Schneiden,
• – Ink-jet-Beschriftung, usw.

Ebenso kann eine Prägestation auch dem Behandlungsmodul 29 vorgelagert sein.After a plasma pretreatment, further processing methods of a known type may follow inline. For this purpose are:

• - printing with conventional or anilox printing units,
• - painting or coating,
• - film application,
• - embossing, punching, cutting,
• - Ink-jet lettering, etc.

Likewise, an embossing station and the treatment module 29 be upstream.

After single feed from the bow plant 10 to the treatment module 29 lying the sheets 12 there on the printing cylinder 30 as a single sheet. Thus, a full-surface treatment of the sheet surface can be made while the press sheet 12 on the printing cylinder 30 kept and guided smoothly. The printing cylinder 30 itself is not provided here with a discharge generating counter electrode.

In comparison to known corona systems which have a counterelectrode, such as a counter-pressure cylinder, metal-coated or metal-coated substrates, as well as films made of plastic, can also be pretreated with the plasma system described here. The so designed facilities 16 . 22 for surface modification can therefore be used for substrates of all currently known types of substrates.

Especially So is the surface modification by means of a discharge on substrates made of substrates with metallic surfaces possible. These are film, paper or board substrates with metallic Lamination in question, such as laminated with aluminum Substrates.

By the configuration of the treatment module 29 there is sufficient space for energy supply and ozone extraction by means of a suction device 31 in front. Thus, the thermal load of the space environment compared to the arrangement in the sheet system 10 to 1 better controllable. The device 16 for surface modification can be moved up or down when not in use. This can be done by moving the entire unit or just the electrodes.

Furthermore, the treatment module 29 with a bow guide 35 above the treatment cylinder (impression cylinder 30 ) be provided.

The described device is used for inline method with Printing and / or varnishing in offset printing units and / or flexo varnishing units or modules. Preferably, the plasma process for surface modification in a first workstation with integrated sheetfed and upstream sheet feeder executed.

In 6 is a plasma treatment in a multifunction module 32 shown, which serves to use additional editing functions.

The sheet guide for the sheet can be touching and / or non-contact, as something air-assisted done. As guide elements rollers, cylinders, movable hold-down rod (about in the sheet inlet in the sheet-fed press) can be used. The guiding elements can also be inside the treatment module 29 or the multifunction module 32 ; before or after the device 16 . 22 be arranged. Alternatively, the device 16 . 22 movable clocking against the surface of the impression cylinder 30 guided print sheet 12 be arranged.

The energy supply and removal, as well as a suction device 31 for gases produced in the process can be used both in the treatment module 29 as well as in the multifunction module 32 be integrated. These are the modules 29 . 32 with protection 27 encapsulated and with in the suction devices 31 integrated filters, insulation, etc. provided.

The counter-cylinder 30 is preferably provided as a solid cylinder with a finished surface or exchangeable surfaces such as with ceramic-coated jackets (coated sheets) or finished sheets on a support such as a skeleton drum with sheet guide plates. In case of wear by thermal abrasion, so the metal jacket can be easily replaced. For this purpose are on the impression cylinder 30 integrated receiving and clamping systems provided.

In 6 is the unit for plasma treatment as a multifunctional module 32 executed. The multifunction module 32 is equipped with changing systems for the use of other additional processing functions. In the multifunction module 32 These are devices for moving or swiveling or removing the device 16 . 22 arranged for surface modification by plasma generation. Alternatively, a stamping cylinder 33 in the multifunction module 32 used or equipped with stamping tools. Furthermore, an ink-jet printing system can also be used 34 be used in the multifunction module. The additional facilities can work together in the multifunction module 32 taken and for common or alternative use against the effective surface of the impression cylinder 30 be arranged slidably.

The multifunction module 32 can also be used alternatively by means of changing equipment or for dual assembly with the said or other working devices for other tasks.

For the resulting functionalities become the existing ones Bow guide devices largely unchanged used.

In inline process with film application, both the substrate, as well as the film to be applied with a plasma process via an associated device according to the device 16 . 22 be treated for surface modification, both devices can cooperate or individual facilities can be used, the associated supply units can be summarized.

10

sheet feeder

11

feed table

12

sheet

13

Arrow / direction of transport

14

pregrippers

15

cylinder

16

Facility

17

line

18

line

19

casing

20

blow nozzle

21

Compressed air connection

22

Facility

23

electrode

24

plasma current

25

Blow air / blast air

26

traverse

27

Verschutzung

28

transfer drum

29

Plasma pre-treatment module

30

pressure cylinder

31

suction

32

Multifunction module

33

Forming / embossing cylinders

34

Ink-jet printing means

35

bowing

40

printing unit

50

printing unit

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10232255 A1 [0005]
• - DE 202004008285 U1 [0006]

Claims (15)

Sheet-fed press, with a feeder for printing sheet to be printed, with at least one printing unit for printing the sheet, with a boom for discharging printed sheet, and with at least one device for surface modification by means of electrical charges each surface of the sheet to a surface tension of the sheet and thus the wettability of the same with printing ink and / or the adhesion of printing ink to the printed sheet, characterized in that the device (s) ( 16 . 22 ) for surface modification of printed sheets of a freely accessible surface of a cylinder ( 30 ) in the sheet leading area associated with the sheet-fed press are integrated. Sheet-fed printing machine according to claim 1, characterized in that as device ( 16 . 22 ) for surface modification of printed sheets at least one device for plasma treatment of sheet surfaces in the region of at least one sheet feed ( 11 . 14 . 15 ) the sheet-fed printing machine downstream plasma treatment module ( 29 ) is integrated in the sheet-fed printing machine. Sheet-fed printing machine according to claim 1 to 2, characterized in that in the device ( 16 . 22 ) is used for the surface modification of printed sheet plasma generated by an electrical discharge between electrodes, which are located on the same side of the surface to be modified and / or on each side of the sheet to be treated. Sheet-fed printing machine according to claim 1 to 3, characterized in that the plasma used for the modification of the sheet surface only during the guidance of a sheet ( 12 ) on the cylinder ( 30 ) is produced in the sheet-fed printing machine and / or that the time and / or the duration of the generation of the plasma used for the modification of the sheet surface are adjustable. Sheet-fed printing machine according to claim 1 to 4, characterized characterized in that the strength of the generation of the for modification the sheet surface used plasma adjustable is and / or that the strength of the surface modification of printed sheets through the plasma on the type of each used Substrates is adjustable and / or that the strength of the Surface modification of printed sheets to the transport speed the print sheet is customizable. Sheet-fed printing machine according to claims 1 to 5, characterized in that by appropriate control of the unit (s) ( 16 . 22 ) for surface modification of printed sheet one or more areas of the substrate surface are recessed transversely and / or longitudinally to the feed direction. Sheet-fed printing machine according to Claim 1 or 2, characterized in that one of the sheet-fed installations ( 10 ) and the sheet feeder ( 11 . 14 . 15 ) downstream processing unit ( 29 ) with one or more facilities ( 16 ) for surface treatment and / or surface modification of printed sheets, the or each device ( 16 ) the area of the impression cylinder ( 30 ), in which the surface of a printed sheet ( 12 ) is freely accessible. Sheet-fed printing machine according to claim 7, characterized in that the processing unit as a plasma treatment module ( 29 ) is formed and that the processing unit has all or essential features of a sheet guiding module or paint module or embossing module. Sheet-fed printing machine according to claim 11, characterized in that the or each device ( 16 . 22 ) in the region of a printing cylinder ( 30 ) or the plasma treatment module ( 29 ) at least one suction device ( 31 ) is arranged in the sheet-fed printing machine, the devices ( 16 . 22 ) is covered by a protection, which has a suction unit for the extraction of the resulting warm process gases. Sheet-fed press according to one or more of the preceding claims, characterized in that the or each device ( 16 . 22 ) for surface modification of the respective surface of the printing sheet has a distance between 5 mm and 10 mm. Sheet-fed press according to one or more of the preceding claims, characterized in that the or each device ( 16 . 22 ) for surface modification of printed sheets has a plurality of electrodes, wherein the electrodes are an array of several rows ( 17 . 18 ) such that the electrodes of adjacent rows ( 17 . 18 ) are offset relative to one another such that at least approximately in the middle between two adjacent electrodes of a row ( 17 . 18 ) an electrode of an adjacent row ( 18 . 17 ) is positioned. Sheet-fed press according to one or more of preceding claims, characterized in that the surface modification preferably on surfaces of plastic printing sheets and / or on plastic coated or laminated and / or on metallic coated or laminated Substrates done. Sheet-fed press according to one or more of the preceding claims, characterized in that with the or each device ( 16 . 22 ) for surface modification by electrical discharges generated plasma can be conducted by a compressed air or gas stream to the surface of the printed sheet to be treated. Sheet-fed printing machine according to claim 13, characterized in that the nozzles ( 20 ) are designed as slit nozzles, which in the transport plane transversely to the direction of movement of the sheet ( 12 ) have a greater extent than in the direction of movement of the printed sheets ( 12 ). Sheet-fed press according to one of the preceding claims, characterized in that the device ( 16 . 22 ) is designed for the surface modification of printed sheet by means of a holder from the region of action on a surface of printed sheet swinging away.