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EP-4739505-A1 - METHOD FOR INSTALLING A PRINTING PLATE ON A SLEEVE, THE SLEEVE AND ASSEMBLIES FOR PRINTING WITH THE PRINTING PLATE

EP4739505A1EP 4739505 A1EP4739505 A1EP 4739505A1EP-4739505-A1

Abstract

The disclosure relates to a method for installing a printing plate on an outer surface of a sleeve, wherein the outer surface of the sleeve is provided with one or more grooves for allowing a gas, such as air or CO2, to escape from between the printing plate and the sleeve; the method comprising: installing the printing plate, preferably with a double-sided tape, on the sleeve over the one or more grooves and such that gas between the printing plate and the sleeve is allowed to escape via the one or more grooves.

Inventors

  • MULLER, UWE
  • MONSTERS, Andreas
  • TANIC, Ayhan
  • SCHMIDT, MARKUS

Assignees

  • XSYS Germany GmbH

Dates

Publication Date
20260513
Application Date
20240703

Claims (20)

  1. 1. A method for installing a printing plate (100) on an outer surface (210) of a sleeve (200), wherein the outer surface (210) of the sleeve is provided with one or more grooves (250) for allowing a gas to escape from between the printing plate and the sleeve; the method comprising: installing the printing plate (100), preferably with an adhesive double-sided tape (150), on the sleeve (200) over the one or more grooves (250) and such that gas between the printing plate (100) and the sleeve (200) is allowed to escape via the one or more grooves.
  2. 2. The method according to the previous claim, further comprising: mounting the sleeve (200) with the printing plate (100) being installed thereon on an outer surface (310) of an adapter (300) or directly on an outer surface (410) of the mandrel (400) while providing a gas cushion, such as an air cushion, between an inner surface (220) of the sleeve (200) and an outer surface (310) of the adapter (300) or an outer surface (410) the mandrel (400); and wherein the gas in the gas cushion is kept separate from gas in the one or more grooves (250) of the sleeve (200).
  3. 3. The method according to the previous claim, further comprising: installing the mandrel (400) on which the sleeve is mounted, optionally while the adapter is arranged between the sleeve and the mandrel, in a printing apparatus.
  4. 4. The method according to any of the previous method claims, further comprising: cleaning the sleeve (200) before the printing plate (100) is installed thereon.
  5. 5. The method according to any of the previous method claims, wherein installing the printing plate comprises applying the adhesive double-sided tape at least partially over the one or more grooves and adhering the printing plate on a top side of the adhesive double-sided taped, wherein preferably the printing plate has a bottom side having a surface area which corresponds to the surface area of the top side of the adhesive double-sided tape.
  6. 6. A sleeve (200) with an outer surface (210) for holding a printing plate (100), wherein the sleeve has an inner surface (220) configured to be mounted on an adapter (300) or directly on a printing mandrel (400) by aid of a gas cushion supplied between the inner surface (220) of the sleeve (200) and an outer surface (310) of the adapter (300) or an outer surface (410) of the mandrel (400); wherein the outer surface of the sleeve is provided with one or more grooves (250) for allowing gas to escape from between the printing plate and the sleeve.
  7. 7. The sleeve according to the previous claim, wherein the outer surface (210) has a total circumferential surface area At, wherein at least 50 %, preferably at least 65%, more preferably at least 75%, even more preferably at least 85 % of the total circumferential surface area At of the outer surface of the sleeve (200) is even such that, when printing, a uniform supporting pressure is given by the outer surface (210) of the sleeve (200) to the printing plate (100).
  8. 8. The sleeve according to the previous claim, wherein the one or more grooves (250) extend over a total grooved area Ag, wherein said total grooved area is at most 50% of the total circumferential surface area surface At of the outer surface of the sleeve (200) and preferably between 0,3 - 50 % of the total surface area surface At, more preferably between 1 - 35 %, even more preferably between 2 - 25 %.
  9. 9. The sleeve according to any of the previous sleeve claims, wherein the grooves (250) include a plurality of grooves distributed over the outer surface (210) of the sleeve (200), preferably equally distributed.
  10. 10. The sleeve according to the previous claim, wherein individual grooves within the plurality of grooves intersect or do not intersect with each other.
  11. 11. The sleeve according to any of the previous two claims, wherein the plurality of grooves are distributed over the outer surface (210) of the sleeve (200) such that at least 0,1 to 10 distinct grooves are present per square centimeter of the outer surface area (210) of the sleeve (200).
  12. 12. The sleeve according to any of the previous sleeve claims, wherein the one or more grooves (250) are isolated from the inner surface (220) of the sleeve, such that any gas transfer between the gas within the one or more grooves (250) and the gas of the gas cushion is prevented.
  13. 13. The sleeve according to any of the previous sleeve claims, wherein the inner surface (220) of the sleeve (200) is configured to slide over the outer surface (310) of the adapter (300) or the outer surface (410) of the mandrel (400).
  14. 14.The sleeve according to any of the previous sleeve claims, wherein the outer surface (210) of the sleeve (200) has a rough texture having a roughness Ra value in the range of 10 pm - 300 pm.
  15. 15. The sleeve according to any of the previous sleeve claims, wherein the sleeve has a wall thickness Tw as measured between the outer surface (210) and inner surface (220), said thickness having a value from 0.5 mm to 150 mm, more preferably 0.5 mm to 135 mm.
  16. 16. The sleeve according to the previous claim, wherein the one or more grooves (250) have a depth in the range of 0,01 to 2 mm, preferably in the range of 0,05 to 1 mm, more preferably in the range of 0,1 to 0,3 mm.
  17. 17. The sleeve according to any of the previous claims, wherein as seen from a cross section, the one or more grooves (250) have a cross-sectional shape chosen from: a triangle, a square, a rectangle, a trapezoid, a partial circle, a partial ellipse, a regular or irregular shape with multiple edges, or combinations thereof.
  18. 18. The sleeve according to any of the previous sleeve claims, wherein the outer surface of the sleeve has a hardness in the range of 30 Shore A and 99 Shore D.
  19. 19.The sleeve according to any of the previous sleeve claims, wherein the sleeve has a total length Ls as measured between a first free edge (201) and second free edge (202) of the sleeve (200); and wherein at least one groove (250) has a longitudinal length Lg which is over at least 30 %, preferably at least 50 %, more preferably at least 75% of the total length Ls of the sleeve (200).
  20. 20. The sleeve according to any of the previous sleeve claims, wherein the sleeve (200) is a layered sleeve structure comprising an outer layer (211) for holding the printing plate (100); and an inner layer (212) for sliding over the mandrel or over the adapter.

Description

METHOD FOR INSTALLING A PRINTING PLATE ON A SLEEVE, THE SLEEVE AND ASSEMBLIES FOR PRINTING WITH THE PRINTING PLATE The present invention relates to the technical field of installing a printing plate on an outer surface of a sleeve, said sleeve and the use thereof. The invention further relates to assemblies for printing with a printing plate, preferably for flexographic printing. BACKGROUND Printing with printing forms or printing plates has long been a conventional practice in the industry. This process involves the transfer of ink by pressing the printing plate onto a substrate to be printed on. Conventional printing plates typically comprise a photopolymer layer that undergoes selective curing, often utilizing UV radiation. The cured portions create a desired relief pattern for printing, while the uncured areas are removed, e.g. washed away in a washer or removed in a thermal development unit. Alternatively, depending on the layer's composition, the opposite effect may be achieved. Before initiating the printing, the printing plate is taken to a mounting station where it is carefully affixed to a sleeve. Subsequently, the sleeve, together with the printing plate, is installed on a mandrel within a printing apparatus. Ink is then applied to the relief pattern of the printing plate. By rotating the mandrel and pressuring on the inked relief pattern against a substrate, an image can be printed on the substrate. Achieving, good and consistent printing results has been forming a challenge within the industry. More so, printing deficiencies may still occur, for example due to improper mounting of the printing plate. Therefore, there is still a need to improve existing techniques of installing a printing plate on a sleeve so that high quality prints can be achieved with the printing plate. SUMMARY OF THE INVENTION An object of embodiments of the present invention is to provide a method allowing an improved arrangement of a printing plate. Thereto, according to a first aspect, there is provided a method for installing a printing plate on an outer surface of a sleeve, wherein the outer surface of the sleeve is provided with one or more grooves for allowing a gas, such as air or CO2 to escape from between the printing plate and the sleeve. The method comprises installing the printing plate, preferably with an adhesive double-sided tape, on the sleeve over the one or more grooves and such that gas between the printing plate and the sleeve is allowed to escape via one or more grooves. Embodiments of the present invention are based on the insight that bubble formation between the printing plate and the sleeve may cause printing deficiencies and impair high quality printing results. Testing and simulations have shown that such bubble formation may be caused by improper mounting and/or caused by gas formation resulting from material outgassing or vapor formation as a result of cleaning agents used to clean the sleeve. By providing the sleeve with one or more grooves, such bubble formation can be avoided as the gas formed under the printing plate can escape via the grooves. As a result, the printing plate can be better adhered to the sleeve and high-quality prints can be achieved with the printing plate. Additionally, the high-quality prints can be achieved more consistently and such consistency results in less waste. Namely, by improving the consistency, scrap works and/or bad prints which are otherwise to be dispensed with are reduced. As a result, there is less waste. Moreover, the inventors have also found that the printing plate can be affixed to a sleeve faster and/or more easily. Namely, in conventional techniques the printing plate has to be carefully affixed to the sleeve and bubble had to be avoided. By having the one or more grooves, the plate can be affixed more rapidly, preferably via a double-sided tape although it is also possible that the plate itself and/or the sleeve itself are provided with adhesive properties and/or that other fixation means are used. According to an embodiment, the method further includes mounting the sleeve with the printing plate being installed thereon on an outer surface of an adapter or directly on an outer surface of a mandrel while providing a gas cushion, such as an air cushion, between an inner surface of the sleeve and an outer surface of the adapter or an outer surface the mandrel. Using the gas cushion facilitates the installing of the sleeve. The gas in the gas cushion is kept separate from gas in the one or more grooves of the sleeve. By keeping the separation of the gas from the gas cushion and the gas in the grooves, one can facilitate the installment of the sleeve by using the gas cushion whilst ensuring that no bubbles are formed as a result of using the gas cushion. According to an embodiment, the method further includes installing the mandrel on which the sleeve is mounted, optionally with the adapter arranged between the sleeve and the mandrel, in a printing a