EP0954443B1 - Method and device for printing on a carrier material using a structured ice layer - Google Patents

Description

The invention relates to a method for generating a Print image on a substrate, in which on a Surface of a print carrier ink-accepting and ink-repellent Areas according to the structure of the print Print image are generated, the ink repelling areas provided with a layer of an ink-repellent medium paint is applied to the surface, the adheres to the ink-attracting areas and those from the ink-repellent areas Areas is not accepted and where the Color distributed on the surface on the carrier material is printed.

The invention further relates to a device for generating a printed image on a carrier material.

In a known offset printing process that works without water the non-printing areas are fat-repellent - they do not accept ink. The printing areas are against it fat-attracting and can absorb fatty paint. The ink-attracting and ink-repellent areas are open a printing plate so distributed that it is to be printed Play the printed image. The printing plate can be used for a variety of transfer printing processes can be used. For every print image must a new printing plate with ink-attracting and ink-repellent Areas are created.

In the well-known DIREKT-IMAGING process from Heidelberger Printing machines is in the printing system on a silicone-coated Film by partially burning away the silicone layer created a print template. The silicone-free Places form the color-attracting areas and can be used during of the printing process.

Another offset method using water are hydrophobic and hydrophilic areas on the print carrier generated according to the structure of the printed image to be printed. Before applying color to the print substrate by using application rollers or spray devices first a thin film of moisture on the print carrier applied, which wets the hydrophilic area of the print medium. Then paint is applied using a paint roller applied to the surface of the print carrier, but only that were not covered with a film of moisture Areas wetted. After inking the print medium finally the colored print image on the carrier material transfer.

Furthermore, one from Océ Printing Systems GmbH developed method known in the hydrophobic and hydrophilic Areas formed on the surface of the print carrier become. The hydrophilic areas are wetted so that there is no color attached to them. The surface is used for wetting of the pressure medium with water vapor. The application with steam can also be done so that hydrophilic Areas according to the structures of the print Print image arise. The ink is only from the areas recorded, which are not provided with a moisture film have been. The above methods have the problem that the ink-water balance is very closely tolerated must be in order to achieve a high print quality.

GB-A-1208731 is a method or a device for generating a print image on a carrier material known. There is a on a surface of a carrier material Solid phase substance applied. This stuff is sensitive to heat and can be exposed to heat structure according to given picture elements, this one solid fabric is removed. The exposed surface of the Print carrier can be brought into a hydrophilic state. Stick when coloring with water-based paint particles these on the hydrophilic areas, while the hydrophobic ones Areas of the solid phase substance these Reject paint particles.

A method and a device is known from ÜS-A-3,741,118 known for printing an image using a technique that is approximately the usual lithography technique corresponds. On a plate is made using electronic Scanning technology selectively applied printing ink or selectively an existing layer removed. The ink on the plate is then transferred to paper. After that the Plate cleaned and can be used to take up ink again be prepared.

It is an object of the invention, a method and a device for generating a print image on a carrier material specify which print images with high resolution generated and largely compatible with previous printing processes or printing devices.

This object is solved by the features of claim 1.

The use of a solid material as an ink-repellent medium has the advantage that there is a sharp boundary between color-accepting and ink repellent areas, which creates the Resolution of the printed image is enlarged. Furthermore results dry running when using a substance in the solid phase and there are no water flags like this conventional printing process is possible. The one from offset printing Known procedure for inking the print carrier and can be retained for transfer printing onto a carrier material become.

An ice layer is preferred as the ink-repellent medium used by condensation of water vapor in the environment of the print medium by spraying on a thin film of water or by applying a water film with roller and subsequent ice formation is deposited on the surface thereof becomes. This layer of ice has a defined shape and a defined volume and sets when exposed to external Forces of a shape or volume change a relatively large one Resistance to, since the water molecules in the solid aggregate state through electromagnetic interactions be tied to specific places. So leave create color-repellent areas with a fine structure, which lead to a high-resolution printed image. By the Addition of a surface tension reducing agent of water, preferably surfactants or alcohol, becomes the ice layer very even and thin. The additives are directly in the water and / or on the print carrier Spray on or apply with a roller. As Another color-repellent medium can be solid release agents such as waxes, fats, resins or fatty acid amides that in the liquid state by spraying or applying with a or several rollers are applied to the print carrier. On the below the solidification temperature of the respective Material cooled printing plate, the medium is in its go over solid phase.

In a preferred embodiment of the invention the print-active surface of the print carrier is initially complete with an ice layer or a release agent layer Wax, fat, resin or fatty acid amides. In one subsequent structuring processes are called color-attracting Creates areas that are free of said solid layer, e.g. the ice layer or release agent layer. In this way, color-attracting areas can be made accordingly the structure of the print image to be printed.

In this embodiment, the surface of the print carrier not according to the structure of the print Pretreated print image, for example by etching. Rather, the pressure-active surface is in its initial state uniform and smooth. The structuring process includes only the generation of solid-free or ice-free Areas according to the structure of the printed image to be printed. Accordingly, on the surface of the print medium a large number of printed images are generated, each for Print image of the initial state of the surface of the print carrier is to be produced. This way you can exchange without generated different print images of the print carrier and inked and re-printed one or more times. When a new print image is applied to the print carrier If so, the print carrier is the one with the solid layer or ice layer as well as areas with paint residues to clean the surface again with a solid layer or ice layer and it takes place new structuring process.

For the selective creation of solid-free or ice-free areas The radiation energy can be found on the surface of the print carrier a laser beam or an LED can be used. Another option is to remove the solids Areas selectively by using heating elements produce.

According to another aspect of the invention, a device specified for performing the described method.

Figur 1

schematisch den Aufbau einer Einrichtung zum Offset-Druck, wobei auf dem Plattenzylinder eine Eisschicht erzeugt wird, und

Figur 2

eine Einrichtung zum Drucken, bei der auf dem Druckträger selektiv Bereiche mit einer Eisschicht erzeugt werden.

Embodiments of the invention are explained below with reference to the drawing. It shows:

Figure 1

schematically the structure of a device for offset printing, wherein an ice layer is generated on the plate cylinder, and

Figure 2

a device for printing, in which areas with an ice layer are selectively produced on the printing medium.

Figure 1 shows schematically the structure of a device for Offset printing. It contains an inking unit 10 with three rollers 12, 14, 16, by the color from an ink reservoir 18 the surface of a plate cylinder 20 formed Print medium is transferred. The colored surface of the Plate cylinder 20 transfers ink to a blanket cylinder 22. From there the ink reaches a paper web 24, by an impression cylinder 26 against the blanket cylinder 22 is pressed. The arrows drawn in Figure 1 indicate the respective transport direction.

The plate cylinder 20 contains tubes for a cooling line system 28 through which coolant is pumped. To the cooling pipe system 28 is a cooling system 34 via hoses 30, 32 connected which coolant with the required Temperature. In the feed line 32 is one Pump P switched on. In operation condenses on the hydrophilic Areas of the surface of the plate cylinder 20 a layer of ice. This layer of ice repels the paint, so that consequently, no color is deposited on the ice layer.

On hydrophobic areas of the surface of the plate cylinder 20 ink is transferred from the roller 16 to the blanket cylinder 22. The hydrophilic and hydrophobic areas on the The surface of the plate cylinder is previously chemical-physical Process applied. Usually is on the outer surface of the plate cylinder 20 as Offset plate serving as a print carrier. To change the This offset plate is to be replaced.

Figure 2 shows schematically a printing device in which different print images on the same surface of the print carrier can be generated. The print medium is here Endless belt 40, around a deflection roller 42, a transfer roller 44 and a cleaning roller 47 is guided around. The surface of the endless belt 40 is by means of a cooling device 46 to a temperature below the solidification point cooled by water. In the case of a normal environment the temperature lies with average humidity the surface of the endless belt 40 below 0 ° C. The in water vapor contained in the ambient air is reflected as a result Condensation on the endless belt 40 as a layer of ice. Through the optional application of a surfactant with the roller ensures a uniformly thin layer of ice. The roller can e.g. close to the type of arrangement of the elements 12, 14, 18 the transfer roller 44 may be provided on the deflection roller 42. Another option is to use a thin film of water to be applied with a thickness in the µm range. By cooling an ice layer then forms. To apply the water film a spray process can be used, or the Application takes place with the help of rollers. The pressure-active surface the endless belt is thus completely covered with a layer of ice Mistake. Then the ice layer is through Energy supply selectively removed, for example by exposure with a laser beam 48, as indicated in Figure 2 is. As an alternative to the ice layer, a release agent layer can also be used made of wax, fat, resin or fatty acid amide be in the liquid state by spraying or Apply to the print carrier with one or more rollers is applied. On the below the solidification temperature of the respective substance cooled printing plate becomes the medium to go into its solid phase.

The exposure is preferably carried out in rows in a grid-like manner, wherein the water of the ice sheet is in the vapor state transforms. Other methods of creating ice-free areas use e.g. the radiation from a laser diode or LED. When arranging an LED array in line form, you can use the entire width of the endless belt 40 at the same time Energy is supplied so that ice-free pixels with high Speed are generated. It is also proposed create ice-free areas using heating elements, which are preferably arranged in a row.

The surface of the endless belt 40 is colored using the rollers 12, 14, which color from the ink reservoir 18 transferred. The color is deposited on areas without ice layer. The areas bearing an ice layer are color-repellent as mentioned and do not absorb any color.

The transfer roller 44 transfers that distributed on the endless belt 40 Paint onto a carrier material fed from the right in FIG. 2 24. The counter-pressure roller 26 presses the carrier material 24, generally paper, against the transfer roller 44.

Two operating modes are possible: With a first operating mode becomes the printed image on the endless belt 40 dyed several times and reprinted. To maintain the structured ice layer on the endless belt 40 are more Cooling devices 50, 52 are provided which cover the layer of ice keep below their solidification temperature.

In a second operating mode, the endless belt 40 is turned on new print image applied. Previously, the previous one is structured Remove ice layer as well as the paint residue and a Defined initial state for the surface of the endless belt 40 manufacture. For this purpose, the cleaning roller 47 a cleaning device 54 is activated. she includes a wiper lip 56 and a brush 58, which with the Surface of the endless belt 40 are brought into contact and remove the structured ice layer. To activate and Deactivating the cleaning station 54 can move this towards arrow 60 are moved. The additional cooling devices 50, 52 are switched off in the second operating mode.

The cooling devices 46, 50, 52 can be of the type shown in FIG 1 cooling device shown. Another possibility consists in the use of an electrothermal Cooling principles, for example by using Peltier elements. It should also be mentioned that the surface of the endless belt 40 made of metals, e.g. made of stainless steel, nickel, copper, Chrome or plastics, e.g. Polyimide, PE, Teflon, or metallized plastics, which one the color binds well in the ice-free areas and thus helps to achieve high print quality.

Reference list

10th

Inking unit

12, 14, 16

roller

18th

Ink reservoir

20th

Plate cylinder

22

Blanket cylinder

24th

Paper web

26

Impression cylinder

28

Cooling pipe system

30, 32

Hoses

34

Cooling system

40

Endless belt

42

Deflection roller

44

Transfer roller

46

Cooling device

47

Cleaning roller

48

laser beam

50, 52

Cooling devices

54

Cleaning device

56

Wiper lip

58

brush

60

arrow

P

pump

Claims (32)

1. Method of producing a printing image on a substrate material,

   in which ink-attracting and ink-repelling areas corresponding to the structure of the printing image to be printed are produced on a surface of a printing substrate (20, 40),

   the ink-repelling areas being provided with a layer of an ink-repelling medium,

   ink being applied to the surface, adhering to the ink-attracting areas and not being picked up by the ink-repelling areas,

   and in which the ink distributed on the surface is printed onto the substrate material (24),

   the ink-repelling medium used being a substance which is found in the solid phase, characterized in that a cooling apparatus (34, 46) is provided which acts on the surface of the printing substrate (20, 40), the solid phase of the substance being produced on the surface of the printing substrate (20, 40) by cooling down the surface of the latter.
2. Method according to Claim 1, characterized in that in order to produce the solid phase of the substance, preferably water, the printing substrate (20, 40) is cooled down, at least on its surface, to a temperature below the solidification temperature of the substance.
3. Method according to one of the preceding claims, characterized in that the active printing surface of the printing substrate (40) is initially completely provided with a layer of a solid element, preferably an ice layer, and in that, in a structuring process, areas free of solid element or ice-free areas are produced as ink-attracting areas corresponding to the structure of the printing image to be printed.
4. Method according to one of the preceding Claims 1 to 3, characterized in that in order to cool down the printing substrate (20, 40), a cooling-liquid system (34) is used.
5. Method according to one of the preceding Claims 1 to 4, characterized in that the printing substrate (20, 40) is cooled down electrothermally, preferably by using Peltier elements.
6. Method according to one of the preceding claims, characterized in that in order to build up the ice-free areas, the ice layer is acted on by radiation (48).
7. Method according to Claim 6, characterized in that the radiation used is the radiation from a laser, a laser diode, an LED or an LED array.
8. Method according to one of the preceding claims, characterized in that the ice-free areas are produced by using heating elements.
9. Method according to one of the preceding claims, characterized in that the surface of the printing substrate (20, 40) is inked with ink by means of a roll system (12, 14, 16), the ink being deposited on the ice-free areas.
10. Method according to one of the preceding claims, characterized in that the inked printing substrate (20, 40) is transfer-printed directly onto the substrate material (24).
11. Method according to one of the preceding claims, characterized in that after being applied to the surface of the printing substrate (20), the ink is initially transferred to an intermediate substrate (22) and is transfer-printed from there onto the substrate material (24).
12. Method according to one of the preceding claims, characterized in that the printing substrate (20, 40) is inked more than once.
13. Method according to one of the preceding claims, characterized in that the surface of the printing substrate consists of metal.
14. Method according to Claim 13, characterized in that the surface of the printing substrate consists of stainless steel, chromium or nickel.
15. Method according to one of the preceding Claims 1 to 12, characterized in that the surface of the printing substrate consists of plastic, in particular of high-temperature resistant plastic.
16. Method according to Claim 15, characterized in that the surface of the printing substrate consists of polyimide or Teflon.
17. Method according to one of the preceding claims, characterized in that the printing substrate consists of metallized plastic.
18. Method according to one of the preceding claims, characterized in that on the surface, a thin liquid film is built up, preferably a water film, liquid being sprayed on or applied by means of rolls in order to produce the liquid film.
19. Method according to one of the preceding claims, characterized in that an additive is provided in order to achieve a uniformly thin ice layer, and in that the additive is applied by being sprayed on or applied by rolls.
20. Method according to one of the preceding claims, characterized in that the substance in solid phase is ice.
21. Method according to one of the preceding claims, characterized in that the substance in solid phase is a release agent.
22. Method according to Claim 21, characterized in that the release agent is wax, grease, resin or fatty acid amide.
23. Method according to one of the preceding claims, characterized in that the substance in solid phase, preferably ice, is deposited by means of condensation.
24. Device for producing a printing image on a substrate material, ink-attracting and ink-repelling areas corresponding to the structure of the printing image to be printed being provided on a surface of a printing substrate (20, 40),

    the ink-repelling areas being provided with a layer of an ink-repelling medium,

    it being possible for ink to be applied to the surface, adhering to the ink-attracting areas and not being picked up by the ink-repelling areas,

    and in which the ink distributed on the surface is printed onto the substrate material (24),

    the ink-repelling medium provided being a substance which is found in the solid phase, characterized in that a cooling apparatus (34, 46) is provided, which acts on the surface of the printing substrate (20, 40), it being possible for the solid phase of the substance to be produced on the said printing substrate (20, 40) by cooling down the surface of the latter.
25. Device according to Claim 24, characterized in that in order to produce the solid phase of the substance, preferably water, the printing substrate (20, 40) is cooled down, at least on its surface, to a temperature below the solidification temperature of the substance by means of a cooling apparatus (28, 30, 32, 34; 46).
26. Device according to one of the preceding claims, characterized in that the active printing surface of the printing substrate (40) is initially completely provided with a layer of a solid element, preferably an ice layer, by employing the cooling apparatus (46), and in that, in a structuring process, areas free of solid element or ice-free areas are produced as ink-attracting areas corresponding to the structure of the printing image to be printed.
27. Device according to one of the preceding claims, characterized in that the printing substrate (20, 40) is cooled down electrothermally, preferably by using Peltier elements.
28. Device according to one of the preceding claims, characterized in that in order to build up the ice-free areas, the ice layer is acted on by radiation (48), the radiation used being the radiation from a laser, a laser diode, an LED or an LED array.
29. Device according to one of the preceding claims, characterized in that the ice-free areas are produced by using heating elements.
30. Device according to one of the preceding claims, characterized in that the surface of the printing substrate (20, 40) can be inked with ink by means of a roll system (12, 14, 16).
31. Device according to one of the preceding claims, characterized in that the inked printing substrate (20, 40) can be transfer-printed directly onto the substrate material (24).
32. Device according to one of the preceding claims, characterized in that after being applied to the surface of the printing substrate (20), the ink can initially be transferred to an intermediate substrate (22) and transfer-printed from there onto the substrate material (24).

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